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David Brownell8ae12a02006-01-08 13:34:19 -08001/*
Grant Likelyca632f52011-06-06 01:16:30 -06002 * SPI init/core code
David Brownell8ae12a02006-01-08 13:34:19 -08003 *
4 * Copyright (C) 2005 David Brownell
Grant Likelyd57a4282012-04-07 14:16:53 -06005 * Copyright (C) 2008 Secret Lab Technologies Ltd.
David Brownell8ae12a02006-01-08 13:34:19 -08006 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 */
21
David Brownell8ae12a02006-01-08 13:34:19 -080022#include <linux/kernel.h>
Grant Likelyd57a4282012-04-07 14:16:53 -060023#include <linux/kmod.h>
David Brownell8ae12a02006-01-08 13:34:19 -080024#include <linux/device.h>
25#include <linux/init.h>
26#include <linux/cache.h>
Mark Brown99adef32014-01-16 12:22:43 +000027#include <linux/dma-mapping.h>
28#include <linux/dmaengine.h>
Matthias Kaehlcke94040822007-07-17 04:04:16 -070029#include <linux/mutex.h>
Sinan Akman2b7a32f2010-10-02 21:28:29 -060030#include <linux/of_device.h>
Grant Likelyd57a4282012-04-07 14:16:53 -060031#include <linux/of_irq.h>
Sylwester Nawrocki86be4082014-06-18 17:29:32 +020032#include <linux/clk/clk-conf.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090033#include <linux/slab.h>
Anton Vorontsove0626e32009-09-22 16:46:08 -070034#include <linux/mod_devicetable.h>
David Brownell8ae12a02006-01-08 13:34:19 -080035#include <linux/spi/spi.h>
Jean-Christophe PLAGNIOL-VILLARD74317982012-11-15 20:19:57 +010036#include <linux/of_gpio.h>
Mark Brown3ae22e82010-12-25 15:32:27 +010037#include <linux/pm_runtime.h>
Ulf Hanssonf48c7672014-09-29 13:58:47 +020038#include <linux/pm_domain.h>
Paul Gortmaker025ed132011-07-10 12:57:55 -040039#include <linux/export.h>
Clark Williams8bd75c72013-02-07 09:47:07 -060040#include <linux/sched/rt.h>
Linus Walleijffbbdd212012-02-22 10:05:38 +010041#include <linux/delay.h>
42#include <linux/kthread.h>
Mika Westerberg64bee4d2012-11-30 12:37:53 +010043#include <linux/ioport.h>
44#include <linux/acpi.h>
David Brownell8ae12a02006-01-08 13:34:19 -080045
Mark Brown56ec1972013-10-07 19:33:53 +010046#define CREATE_TRACE_POINTS
47#include <trace/events/spi.h>
48
David Brownell8ae12a02006-01-08 13:34:19 -080049static void spidev_release(struct device *dev)
50{
Hans-Peter Nilsson0ffa0282007-02-12 00:52:45 -080051 struct spi_device *spi = to_spi_device(dev);
David Brownell8ae12a02006-01-08 13:34:19 -080052
53 /* spi masters may cleanup for released devices */
54 if (spi->master->cleanup)
55 spi->master->cleanup(spi);
56
David Brownell0c868462006-01-08 13:34:25 -080057 spi_master_put(spi->master);
Roman Tereshonkov07a389f2010-04-12 09:56:35 +000058 kfree(spi);
David Brownell8ae12a02006-01-08 13:34:19 -080059}
60
61static ssize_t
62modalias_show(struct device *dev, struct device_attribute *a, char *buf)
63{
64 const struct spi_device *spi = to_spi_device(dev);
Zhang Rui8c4ff6d2014-01-14 16:46:37 +080065 int len;
66
67 len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
68 if (len != -ENODEV)
69 return len;
David Brownell8ae12a02006-01-08 13:34:19 -080070
Grant Likelyd8e328b2012-05-20 00:08:13 -060071 return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
David Brownell8ae12a02006-01-08 13:34:19 -080072}
Greg Kroah-Hartmanaa7da562013-10-07 18:27:38 -070073static DEVICE_ATTR_RO(modalias);
David Brownell8ae12a02006-01-08 13:34:19 -080074
Greg Kroah-Hartmanaa7da562013-10-07 18:27:38 -070075static struct attribute *spi_dev_attrs[] = {
76 &dev_attr_modalias.attr,
77 NULL,
David Brownell8ae12a02006-01-08 13:34:19 -080078};
Greg Kroah-Hartmanaa7da562013-10-07 18:27:38 -070079ATTRIBUTE_GROUPS(spi_dev);
David Brownell8ae12a02006-01-08 13:34:19 -080080
81/* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
82 * and the sysfs version makes coldplug work too.
83 */
84
Anton Vorontsov75368bf2009-09-22 16:46:04 -070085static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
86 const struct spi_device *sdev)
87{
88 while (id->name[0]) {
89 if (!strcmp(sdev->modalias, id->name))
90 return id;
91 id++;
92 }
93 return NULL;
94}
95
96const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
97{
98 const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
99
100 return spi_match_id(sdrv->id_table, sdev);
101}
102EXPORT_SYMBOL_GPL(spi_get_device_id);
103
David Brownell8ae12a02006-01-08 13:34:19 -0800104static int spi_match_device(struct device *dev, struct device_driver *drv)
105{
106 const struct spi_device *spi = to_spi_device(dev);
Anton Vorontsov75368bf2009-09-22 16:46:04 -0700107 const struct spi_driver *sdrv = to_spi_driver(drv);
108
Sinan Akman2b7a32f2010-10-02 21:28:29 -0600109 /* Attempt an OF style match */
110 if (of_driver_match_device(dev, drv))
111 return 1;
112
Mika Westerberg64bee4d2012-11-30 12:37:53 +0100113 /* Then try ACPI */
114 if (acpi_driver_match_device(dev, drv))
115 return 1;
116
Anton Vorontsov75368bf2009-09-22 16:46:04 -0700117 if (sdrv->id_table)
118 return !!spi_match_id(sdrv->id_table, spi);
David Brownell8ae12a02006-01-08 13:34:19 -0800119
Kay Sievers35f74fc2009-01-06 10:44:37 -0800120 return strcmp(spi->modalias, drv->name) == 0;
David Brownell8ae12a02006-01-08 13:34:19 -0800121}
122
Kay Sievers7eff2e72007-08-14 15:15:12 +0200123static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
David Brownell8ae12a02006-01-08 13:34:19 -0800124{
125 const struct spi_device *spi = to_spi_device(dev);
Zhang Rui8c4ff6d2014-01-14 16:46:37 +0800126 int rc;
127
128 rc = acpi_device_uevent_modalias(dev, env);
129 if (rc != -ENODEV)
130 return rc;
David Brownell8ae12a02006-01-08 13:34:19 -0800131
Anton Vorontsove0626e32009-09-22 16:46:08 -0700132 add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
David Brownell8ae12a02006-01-08 13:34:19 -0800133 return 0;
134}
135
Mark Brown3ae22e82010-12-25 15:32:27 +0100136#ifdef CONFIG_PM_SLEEP
137static int spi_legacy_suspend(struct device *dev, pm_message_t message)
David Brownell8ae12a02006-01-08 13:34:19 -0800138{
David Brownell3c724262008-02-06 01:38:10 -0800139 int value = 0;
David Brownellb8852442006-01-08 13:34:23 -0800140 struct spi_driver *drv = to_spi_driver(dev->driver);
David Brownell8ae12a02006-01-08 13:34:19 -0800141
David Brownell8ae12a02006-01-08 13:34:19 -0800142 /* suspend will stop irqs and dma; no more i/o */
David Brownell3c724262008-02-06 01:38:10 -0800143 if (drv) {
144 if (drv->suspend)
145 value = drv->suspend(to_spi_device(dev), message);
146 else
147 dev_dbg(dev, "... can't suspend\n");
148 }
David Brownell8ae12a02006-01-08 13:34:19 -0800149 return value;
150}
151
Mark Brown3ae22e82010-12-25 15:32:27 +0100152static int spi_legacy_resume(struct device *dev)
David Brownell8ae12a02006-01-08 13:34:19 -0800153{
David Brownell3c724262008-02-06 01:38:10 -0800154 int value = 0;
David Brownellb8852442006-01-08 13:34:23 -0800155 struct spi_driver *drv = to_spi_driver(dev->driver);
David Brownell8ae12a02006-01-08 13:34:19 -0800156
David Brownell8ae12a02006-01-08 13:34:19 -0800157 /* resume may restart the i/o queue */
David Brownell3c724262008-02-06 01:38:10 -0800158 if (drv) {
159 if (drv->resume)
160 value = drv->resume(to_spi_device(dev));
161 else
162 dev_dbg(dev, "... can't resume\n");
163 }
David Brownell8ae12a02006-01-08 13:34:19 -0800164 return value;
165}
166
Mark Brown3ae22e82010-12-25 15:32:27 +0100167static int spi_pm_suspend(struct device *dev)
168{
169 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
170
171 if (pm)
172 return pm_generic_suspend(dev);
173 else
174 return spi_legacy_suspend(dev, PMSG_SUSPEND);
175}
176
177static int spi_pm_resume(struct device *dev)
178{
179 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
180
181 if (pm)
182 return pm_generic_resume(dev);
183 else
184 return spi_legacy_resume(dev);
185}
186
187static int spi_pm_freeze(struct device *dev)
188{
189 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
190
191 if (pm)
192 return pm_generic_freeze(dev);
193 else
194 return spi_legacy_suspend(dev, PMSG_FREEZE);
195}
196
197static int spi_pm_thaw(struct device *dev)
198{
199 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
200
201 if (pm)
202 return pm_generic_thaw(dev);
203 else
204 return spi_legacy_resume(dev);
205}
206
207static int spi_pm_poweroff(struct device *dev)
208{
209 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
210
211 if (pm)
212 return pm_generic_poweroff(dev);
213 else
214 return spi_legacy_suspend(dev, PMSG_HIBERNATE);
215}
216
217static int spi_pm_restore(struct device *dev)
218{
219 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
220
221 if (pm)
222 return pm_generic_restore(dev);
223 else
224 return spi_legacy_resume(dev);
225}
David Brownell8ae12a02006-01-08 13:34:19 -0800226#else
Mark Brown3ae22e82010-12-25 15:32:27 +0100227#define spi_pm_suspend NULL
228#define spi_pm_resume NULL
229#define spi_pm_freeze NULL
230#define spi_pm_thaw NULL
231#define spi_pm_poweroff NULL
232#define spi_pm_restore NULL
David Brownell8ae12a02006-01-08 13:34:19 -0800233#endif
234
Mark Brown3ae22e82010-12-25 15:32:27 +0100235static const struct dev_pm_ops spi_pm = {
236 .suspend = spi_pm_suspend,
237 .resume = spi_pm_resume,
238 .freeze = spi_pm_freeze,
239 .thaw = spi_pm_thaw,
240 .poweroff = spi_pm_poweroff,
241 .restore = spi_pm_restore,
242 SET_RUNTIME_PM_OPS(
243 pm_generic_runtime_suspend,
244 pm_generic_runtime_resume,
Rafael J. Wysocki45f0a852013-06-03 21:49:52 +0200245 NULL
Mark Brown3ae22e82010-12-25 15:32:27 +0100246 )
247};
248
David Brownell8ae12a02006-01-08 13:34:19 -0800249struct bus_type spi_bus_type = {
250 .name = "spi",
Greg Kroah-Hartmanaa7da562013-10-07 18:27:38 -0700251 .dev_groups = spi_dev_groups,
David Brownell8ae12a02006-01-08 13:34:19 -0800252 .match = spi_match_device,
253 .uevent = spi_uevent,
Mark Brown3ae22e82010-12-25 15:32:27 +0100254 .pm = &spi_pm,
David Brownell8ae12a02006-01-08 13:34:19 -0800255};
256EXPORT_SYMBOL_GPL(spi_bus_type);
257
David Brownellb8852442006-01-08 13:34:23 -0800258
259static int spi_drv_probe(struct device *dev)
260{
261 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
Mika Westerberg33cf00e2013-10-10 13:28:48 +0300262 int ret;
David Brownellb8852442006-01-08 13:34:23 -0800263
Sylwester Nawrocki86be4082014-06-18 17:29:32 +0200264 ret = of_clk_set_defaults(dev->of_node, false);
265 if (ret)
266 return ret;
267
Ulf Hansson676e7c22014-09-19 20:27:41 +0200268 ret = dev_pm_domain_attach(dev, true);
269 if (ret != -EPROBE_DEFER) {
270 ret = sdrv->probe(to_spi_device(dev));
271 if (ret)
272 dev_pm_domain_detach(dev, true);
273 }
Mika Westerberg33cf00e2013-10-10 13:28:48 +0300274
275 return ret;
David Brownellb8852442006-01-08 13:34:23 -0800276}
277
278static int spi_drv_remove(struct device *dev)
279{
280 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
Mika Westerberg33cf00e2013-10-10 13:28:48 +0300281 int ret;
David Brownellb8852442006-01-08 13:34:23 -0800282
Jean Delvareaec35f42014-02-13 15:28:41 +0100283 ret = sdrv->remove(to_spi_device(dev));
Ulf Hansson676e7c22014-09-19 20:27:41 +0200284 dev_pm_domain_detach(dev, true);
Mika Westerberg33cf00e2013-10-10 13:28:48 +0300285
286 return ret;
David Brownellb8852442006-01-08 13:34:23 -0800287}
288
289static void spi_drv_shutdown(struct device *dev)
290{
291 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
292
293 sdrv->shutdown(to_spi_device(dev));
294}
295
David Brownell33e34dc2007-05-08 00:32:21 -0700296/**
297 * spi_register_driver - register a SPI driver
298 * @sdrv: the driver to register
299 * Context: can sleep
300 */
David Brownellb8852442006-01-08 13:34:23 -0800301int spi_register_driver(struct spi_driver *sdrv)
302{
303 sdrv->driver.bus = &spi_bus_type;
304 if (sdrv->probe)
305 sdrv->driver.probe = spi_drv_probe;
306 if (sdrv->remove)
307 sdrv->driver.remove = spi_drv_remove;
308 if (sdrv->shutdown)
309 sdrv->driver.shutdown = spi_drv_shutdown;
310 return driver_register(&sdrv->driver);
311}
312EXPORT_SYMBOL_GPL(spi_register_driver);
313
David Brownell8ae12a02006-01-08 13:34:19 -0800314/*-------------------------------------------------------------------------*/
315
316/* SPI devices should normally not be created by SPI device drivers; that
317 * would make them board-specific. Similarly with SPI master drivers.
318 * Device registration normally goes into like arch/.../mach.../board-YYY.c
319 * with other readonly (flashable) information about mainboard devices.
320 */
321
322struct boardinfo {
323 struct list_head list;
Feng Tang2b9603a2010-08-02 15:52:15 +0800324 struct spi_board_info board_info;
David Brownell8ae12a02006-01-08 13:34:19 -0800325};
326
327static LIST_HEAD(board_list);
Feng Tang2b9603a2010-08-02 15:52:15 +0800328static LIST_HEAD(spi_master_list);
329
330/*
331 * Used to protect add/del opertion for board_info list and
332 * spi_master list, and their matching process
333 */
Matthias Kaehlcke94040822007-07-17 04:04:16 -0700334static DEFINE_MUTEX(board_lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800335
Grant Likelydc87c982008-05-15 16:50:22 -0600336/**
337 * spi_alloc_device - Allocate a new SPI device
338 * @master: Controller to which device is connected
339 * Context: can sleep
340 *
341 * Allows a driver to allocate and initialize a spi_device without
342 * registering it immediately. This allows a driver to directly
343 * fill the spi_device with device parameters before calling
344 * spi_add_device() on it.
345 *
346 * Caller is responsible to call spi_add_device() on the returned
347 * spi_device structure to add it to the SPI master. If the caller
348 * needs to discard the spi_device without adding it, then it should
349 * call spi_dev_put() on it.
350 *
351 * Returns a pointer to the new device, or NULL.
352 */
353struct spi_device *spi_alloc_device(struct spi_master *master)
354{
355 struct spi_device *spi;
Grant Likelydc87c982008-05-15 16:50:22 -0600356
357 if (!spi_master_get(master))
358 return NULL;
359
Jingoo Han5fe5f052013-10-14 10:31:51 +0900360 spi = kzalloc(sizeof(*spi), GFP_KERNEL);
Grant Likelydc87c982008-05-15 16:50:22 -0600361 if (!spi) {
Grant Likelydc87c982008-05-15 16:50:22 -0600362 spi_master_put(master);
363 return NULL;
364 }
365
366 spi->master = master;
Laurent Pinchart178db7d2011-12-12 01:15:06 +0100367 spi->dev.parent = &master->dev;
Grant Likelydc87c982008-05-15 16:50:22 -0600368 spi->dev.bus = &spi_bus_type;
369 spi->dev.release = spidev_release;
Andreas Larsson446411e2013-02-13 14:20:25 +0100370 spi->cs_gpio = -ENOENT;
Grant Likelydc87c982008-05-15 16:50:22 -0600371 device_initialize(&spi->dev);
372 return spi;
373}
374EXPORT_SYMBOL_GPL(spi_alloc_device);
375
Jarkko Nikulae13ac472013-11-14 14:03:53 +0200376static void spi_dev_set_name(struct spi_device *spi)
377{
378 struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
379
380 if (adev) {
381 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
382 return;
383 }
384
385 dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
386 spi->chip_select);
387}
388
Mika Westerbergb6fb8d32014-01-09 15:23:55 +0200389static int spi_dev_check(struct device *dev, void *data)
390{
391 struct spi_device *spi = to_spi_device(dev);
392 struct spi_device *new_spi = data;
393
394 if (spi->master == new_spi->master &&
395 spi->chip_select == new_spi->chip_select)
396 return -EBUSY;
397 return 0;
398}
399
Grant Likelydc87c982008-05-15 16:50:22 -0600400/**
401 * spi_add_device - Add spi_device allocated with spi_alloc_device
402 * @spi: spi_device to register
403 *
404 * Companion function to spi_alloc_device. Devices allocated with
405 * spi_alloc_device can be added onto the spi bus with this function.
406 *
David Brownelle48880e2008-08-15 00:40:44 -0700407 * Returns 0 on success; negative errno on failure
Grant Likelydc87c982008-05-15 16:50:22 -0600408 */
409int spi_add_device(struct spi_device *spi)
410{
David Brownelle48880e2008-08-15 00:40:44 -0700411 static DEFINE_MUTEX(spi_add_lock);
Jean-Christophe PLAGNIOL-VILLARD74317982012-11-15 20:19:57 +0100412 struct spi_master *master = spi->master;
413 struct device *dev = master->dev.parent;
Grant Likelydc87c982008-05-15 16:50:22 -0600414 int status;
415
416 /* Chipselects are numbered 0..max; validate. */
Jean-Christophe PLAGNIOL-VILLARD74317982012-11-15 20:19:57 +0100417 if (spi->chip_select >= master->num_chipselect) {
Grant Likelydc87c982008-05-15 16:50:22 -0600418 dev_err(dev, "cs%d >= max %d\n",
419 spi->chip_select,
Jean-Christophe PLAGNIOL-VILLARD74317982012-11-15 20:19:57 +0100420 master->num_chipselect);
Grant Likelydc87c982008-05-15 16:50:22 -0600421 return -EINVAL;
422 }
423
424 /* Set the bus ID string */
Jarkko Nikulae13ac472013-11-14 14:03:53 +0200425 spi_dev_set_name(spi);
David Brownelle48880e2008-08-15 00:40:44 -0700426
427 /* We need to make sure there's no other device with this
428 * chipselect **BEFORE** we call setup(), else we'll trash
429 * its configuration. Lock against concurrent add() calls.
430 */
431 mutex_lock(&spi_add_lock);
432
Mika Westerbergb6fb8d32014-01-09 15:23:55 +0200433 status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
434 if (status) {
David Brownelle48880e2008-08-15 00:40:44 -0700435 dev_err(dev, "chipselect %d already in use\n",
436 spi->chip_select);
David Brownelle48880e2008-08-15 00:40:44 -0700437 goto done;
438 }
439
Jean-Christophe PLAGNIOL-VILLARD74317982012-11-15 20:19:57 +0100440 if (master->cs_gpios)
441 spi->cs_gpio = master->cs_gpios[spi->chip_select];
442
David Brownelle48880e2008-08-15 00:40:44 -0700443 /* Drivers may modify this initial i/o setup, but will
444 * normally rely on the device being setup. Devices
445 * using SPI_CS_HIGH can't coexist well otherwise...
446 */
David Brownell7d077192009-06-17 16:26:03 -0700447 status = spi_setup(spi);
Grant Likelydc87c982008-05-15 16:50:22 -0600448 if (status < 0) {
Linus Walleijeb288a12010-10-21 21:06:44 +0200449 dev_err(dev, "can't setup %s, status %d\n",
450 dev_name(&spi->dev), status);
David Brownelle48880e2008-08-15 00:40:44 -0700451 goto done;
Grant Likelydc87c982008-05-15 16:50:22 -0600452 }
453
David Brownelle48880e2008-08-15 00:40:44 -0700454 /* Device may be bound to an active driver when this returns */
Grant Likelydc87c982008-05-15 16:50:22 -0600455 status = device_add(&spi->dev);
David Brownelle48880e2008-08-15 00:40:44 -0700456 if (status < 0)
Linus Walleijeb288a12010-10-21 21:06:44 +0200457 dev_err(dev, "can't add %s, status %d\n",
458 dev_name(&spi->dev), status);
David Brownelle48880e2008-08-15 00:40:44 -0700459 else
Kay Sievers35f74fc2009-01-06 10:44:37 -0800460 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
Grant Likelydc87c982008-05-15 16:50:22 -0600461
David Brownelle48880e2008-08-15 00:40:44 -0700462done:
463 mutex_unlock(&spi_add_lock);
464 return status;
Grant Likelydc87c982008-05-15 16:50:22 -0600465}
466EXPORT_SYMBOL_GPL(spi_add_device);
David Brownell8ae12a02006-01-08 13:34:19 -0800467
David Brownell33e34dc2007-05-08 00:32:21 -0700468/**
469 * spi_new_device - instantiate one new SPI device
470 * @master: Controller to which device is connected
471 * @chip: Describes the SPI device
472 * Context: can sleep
473 *
474 * On typical mainboards, this is purely internal; and it's not needed
David Brownell8ae12a02006-01-08 13:34:19 -0800475 * after board init creates the hard-wired devices. Some development
476 * platforms may not be able to use spi_register_board_info though, and
477 * this is exported so that for example a USB or parport based adapter
478 * driver could add devices (which it would learn about out-of-band).
David Brownell082c8cb2007-07-31 00:39:45 -0700479 *
480 * Returns the new device, or NULL.
David Brownell8ae12a02006-01-08 13:34:19 -0800481 */
Adrian Bunke9d5a462007-03-26 21:32:23 -0800482struct spi_device *spi_new_device(struct spi_master *master,
483 struct spi_board_info *chip)
David Brownell8ae12a02006-01-08 13:34:19 -0800484{
485 struct spi_device *proxy;
David Brownell8ae12a02006-01-08 13:34:19 -0800486 int status;
487
David Brownell082c8cb2007-07-31 00:39:45 -0700488 /* NOTE: caller did any chip->bus_num checks necessary.
489 *
490 * Also, unless we change the return value convention to use
491 * error-or-pointer (not NULL-or-pointer), troubleshootability
492 * suggests syslogged diagnostics are best here (ugh).
493 */
494
Grant Likelydc87c982008-05-15 16:50:22 -0600495 proxy = spi_alloc_device(master);
496 if (!proxy)
David Brownell8ae12a02006-01-08 13:34:19 -0800497 return NULL;
498
Grant Likely102eb972008-07-23 21:29:55 -0700499 WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
500
David Brownell8ae12a02006-01-08 13:34:19 -0800501 proxy->chip_select = chip->chip_select;
502 proxy->max_speed_hz = chip->max_speed_hz;
David Brownell980a01c2006-06-28 07:47:15 -0700503 proxy->mode = chip->mode;
David Brownell8ae12a02006-01-08 13:34:19 -0800504 proxy->irq = chip->irq;
Grant Likely102eb972008-07-23 21:29:55 -0700505 strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
David Brownell8ae12a02006-01-08 13:34:19 -0800506 proxy->dev.platform_data = (void *) chip->platform_data;
507 proxy->controller_data = chip->controller_data;
508 proxy->controller_state = NULL;
David Brownell8ae12a02006-01-08 13:34:19 -0800509
Grant Likelydc87c982008-05-15 16:50:22 -0600510 status = spi_add_device(proxy);
David Brownell8ae12a02006-01-08 13:34:19 -0800511 if (status < 0) {
Grant Likelydc87c982008-05-15 16:50:22 -0600512 spi_dev_put(proxy);
513 return NULL;
David Brownell8ae12a02006-01-08 13:34:19 -0800514 }
515
David Brownell8ae12a02006-01-08 13:34:19 -0800516 return proxy;
517}
518EXPORT_SYMBOL_GPL(spi_new_device);
519
Feng Tang2b9603a2010-08-02 15:52:15 +0800520static void spi_match_master_to_boardinfo(struct spi_master *master,
521 struct spi_board_info *bi)
522{
523 struct spi_device *dev;
524
525 if (master->bus_num != bi->bus_num)
526 return;
527
528 dev = spi_new_device(master, bi);
529 if (!dev)
530 dev_err(master->dev.parent, "can't create new device for %s\n",
531 bi->modalias);
532}
533
David Brownell33e34dc2007-05-08 00:32:21 -0700534/**
535 * spi_register_board_info - register SPI devices for a given board
536 * @info: array of chip descriptors
537 * @n: how many descriptors are provided
538 * Context: can sleep
539 *
David Brownell8ae12a02006-01-08 13:34:19 -0800540 * Board-specific early init code calls this (probably during arch_initcall)
541 * with segments of the SPI device table. Any device nodes are created later,
542 * after the relevant parent SPI controller (bus_num) is defined. We keep
543 * this table of devices forever, so that reloading a controller driver will
544 * not make Linux forget about these hard-wired devices.
545 *
546 * Other code can also call this, e.g. a particular add-on board might provide
547 * SPI devices through its expansion connector, so code initializing that board
548 * would naturally declare its SPI devices.
549 *
550 * The board info passed can safely be __initdata ... but be careful of
551 * any embedded pointers (platform_data, etc), they're copied as-is.
552 */
Grant Likelyfd4a3192012-12-07 16:57:14 +0000553int spi_register_board_info(struct spi_board_info const *info, unsigned n)
David Brownell8ae12a02006-01-08 13:34:19 -0800554{
Feng Tang2b9603a2010-08-02 15:52:15 +0800555 struct boardinfo *bi;
556 int i;
David Brownell8ae12a02006-01-08 13:34:19 -0800557
Xiubo Lic7908a32014-09-24 14:30:29 +0800558 if (!n)
559 return -EINVAL;
560
Feng Tang2b9603a2010-08-02 15:52:15 +0800561 bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
David Brownell8ae12a02006-01-08 13:34:19 -0800562 if (!bi)
563 return -ENOMEM;
David Brownell8ae12a02006-01-08 13:34:19 -0800564
Feng Tang2b9603a2010-08-02 15:52:15 +0800565 for (i = 0; i < n; i++, bi++, info++) {
566 struct spi_master *master;
David Brownell8ae12a02006-01-08 13:34:19 -0800567
Feng Tang2b9603a2010-08-02 15:52:15 +0800568 memcpy(&bi->board_info, info, sizeof(*info));
569 mutex_lock(&board_lock);
570 list_add_tail(&bi->list, &board_list);
571 list_for_each_entry(master, &spi_master_list, list)
572 spi_match_master_to_boardinfo(master, &bi->board_info);
573 mutex_unlock(&board_lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800574 }
Feng Tang2b9603a2010-08-02 15:52:15 +0800575
576 return 0;
David Brownell8ae12a02006-01-08 13:34:19 -0800577}
578
579/*-------------------------------------------------------------------------*/
580
Mark Brownb1589352013-10-05 11:50:40 +0100581static void spi_set_cs(struct spi_device *spi, bool enable)
582{
583 if (spi->mode & SPI_CS_HIGH)
584 enable = !enable;
585
586 if (spi->cs_gpio >= 0)
587 gpio_set_value(spi->cs_gpio, !enable);
588 else if (spi->master->set_cs)
589 spi->master->set_cs(spi, !enable);
590}
591
Geert Uytterhoeven2de440f2014-05-02 06:29:34 +0200592#ifdef CONFIG_HAS_DMA
Mark Brown6ad45a22014-02-02 13:47:47 +0000593static int spi_map_buf(struct spi_master *master, struct device *dev,
594 struct sg_table *sgt, void *buf, size_t len,
595 enum dma_data_direction dir)
596{
597 const bool vmalloced_buf = is_vmalloc_addr(buf);
598 const int desc_len = vmalloced_buf ? PAGE_SIZE : master->max_dma_len;
599 const int sgs = DIV_ROUND_UP(len, desc_len);
600 struct page *vm_page;
601 void *sg_buf;
602 size_t min;
603 int i, ret;
604
605 ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
606 if (ret != 0)
607 return ret;
608
609 for (i = 0; i < sgs; i++) {
610 min = min_t(size_t, len, desc_len);
611
612 if (vmalloced_buf) {
613 vm_page = vmalloc_to_page(buf);
614 if (!vm_page) {
615 sg_free_table(sgt);
616 return -ENOMEM;
617 }
618 sg_buf = page_address(vm_page) +
619 ((size_t)buf & ~PAGE_MASK);
620 } else {
621 sg_buf = buf;
622 }
623
624 sg_set_buf(&sgt->sgl[i], sg_buf, min);
625
626 buf += min;
627 len -= min;
628 }
629
630 ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
Geert Uytterhoeven89e4b662014-07-10 15:29:32 +0200631 if (!ret)
632 ret = -ENOMEM;
Mark Brown6ad45a22014-02-02 13:47:47 +0000633 if (ret < 0) {
634 sg_free_table(sgt);
635 return ret;
636 }
637
638 sgt->nents = ret;
639
640 return 0;
641}
642
643static void spi_unmap_buf(struct spi_master *master, struct device *dev,
644 struct sg_table *sgt, enum dma_data_direction dir)
645{
646 if (sgt->orig_nents) {
647 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
648 sg_free_table(sgt);
649 }
650}
651
Geert Uytterhoeven2de440f2014-05-02 06:29:34 +0200652static int __spi_map_msg(struct spi_master *master, struct spi_message *msg)
Mark Brown99adef32014-01-16 12:22:43 +0000653{
Mark Brown99adef32014-01-16 12:22:43 +0000654 struct device *tx_dev, *rx_dev;
655 struct spi_transfer *xfer;
Mark Brown6ad45a22014-02-02 13:47:47 +0000656 int ret;
Mark Brown3a2eba92014-01-28 20:17:03 +0000657
Mark Brown6ad45a22014-02-02 13:47:47 +0000658 if (!master->can_dma)
Mark Brown99adef32014-01-16 12:22:43 +0000659 return 0;
660
Geert Uytterhoeven3fc25422014-07-10 15:29:33 +0200661 tx_dev = master->dma_tx->device->dev;
662 rx_dev = master->dma_rx->device->dev;
Mark Brown99adef32014-01-16 12:22:43 +0000663
664 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
665 if (!master->can_dma(master, msg->spi, xfer))
666 continue;
667
668 if (xfer->tx_buf != NULL) {
Mark Brown6ad45a22014-02-02 13:47:47 +0000669 ret = spi_map_buf(master, tx_dev, &xfer->tx_sg,
670 (void *)xfer->tx_buf, xfer->len,
671 DMA_TO_DEVICE);
672 if (ret != 0)
673 return ret;
Mark Brown99adef32014-01-16 12:22:43 +0000674 }
675
676 if (xfer->rx_buf != NULL) {
Mark Brown6ad45a22014-02-02 13:47:47 +0000677 ret = spi_map_buf(master, rx_dev, &xfer->rx_sg,
678 xfer->rx_buf, xfer->len,
679 DMA_FROM_DEVICE);
680 if (ret != 0) {
681 spi_unmap_buf(master, tx_dev, &xfer->tx_sg,
682 DMA_TO_DEVICE);
683 return ret;
Mark Brown99adef32014-01-16 12:22:43 +0000684 }
685 }
686 }
687
688 master->cur_msg_mapped = true;
689
690 return 0;
691}
692
693static int spi_unmap_msg(struct spi_master *master, struct spi_message *msg)
694{
695 struct spi_transfer *xfer;
696 struct device *tx_dev, *rx_dev;
697
Mark Brown6ad45a22014-02-02 13:47:47 +0000698 if (!master->cur_msg_mapped || !master->can_dma)
Mark Brown99adef32014-01-16 12:22:43 +0000699 return 0;
700
Geert Uytterhoeven3fc25422014-07-10 15:29:33 +0200701 tx_dev = master->dma_tx->device->dev;
702 rx_dev = master->dma_rx->device->dev;
Mark Brown99adef32014-01-16 12:22:43 +0000703
704 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
705 if (!master->can_dma(master, msg->spi, xfer))
706 continue;
707
Mark Brown6ad45a22014-02-02 13:47:47 +0000708 spi_unmap_buf(master, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
709 spi_unmap_buf(master, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
Mark Brown99adef32014-01-16 12:22:43 +0000710 }
711
712 return 0;
713}
Geert Uytterhoeven2de440f2014-05-02 06:29:34 +0200714#else /* !CONFIG_HAS_DMA */
715static inline int __spi_map_msg(struct spi_master *master,
716 struct spi_message *msg)
717{
718 return 0;
719}
720
721static inline int spi_unmap_msg(struct spi_master *master,
722 struct spi_message *msg)
723{
724 return 0;
725}
726#endif /* !CONFIG_HAS_DMA */
727
728static int spi_map_msg(struct spi_master *master, struct spi_message *msg)
729{
730 struct spi_transfer *xfer;
731 void *tmp;
732 unsigned int max_tx, max_rx;
733
734 if (master->flags & (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX)) {
735 max_tx = 0;
736 max_rx = 0;
737
738 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
739 if ((master->flags & SPI_MASTER_MUST_TX) &&
740 !xfer->tx_buf)
741 max_tx = max(xfer->len, max_tx);
742 if ((master->flags & SPI_MASTER_MUST_RX) &&
743 !xfer->rx_buf)
744 max_rx = max(xfer->len, max_rx);
745 }
746
747 if (max_tx) {
748 tmp = krealloc(master->dummy_tx, max_tx,
749 GFP_KERNEL | GFP_DMA);
750 if (!tmp)
751 return -ENOMEM;
752 master->dummy_tx = tmp;
753 memset(tmp, 0, max_tx);
754 }
755
756 if (max_rx) {
757 tmp = krealloc(master->dummy_rx, max_rx,
758 GFP_KERNEL | GFP_DMA);
759 if (!tmp)
760 return -ENOMEM;
761 master->dummy_rx = tmp;
762 }
763
764 if (max_tx || max_rx) {
765 list_for_each_entry(xfer, &msg->transfers,
766 transfer_list) {
767 if (!xfer->tx_buf)
768 xfer->tx_buf = master->dummy_tx;
769 if (!xfer->rx_buf)
770 xfer->rx_buf = master->dummy_rx;
771 }
772 }
773 }
774
775 return __spi_map_msg(master, msg);
776}
Mark Brown99adef32014-01-16 12:22:43 +0000777
Mark Brownb1589352013-10-05 11:50:40 +0100778/*
779 * spi_transfer_one_message - Default implementation of transfer_one_message()
780 *
781 * This is a standard implementation of transfer_one_message() for
782 * drivers which impelment a transfer_one() operation. It provides
783 * standard handling of delays and chip select management.
784 */
785static int spi_transfer_one_message(struct spi_master *master,
786 struct spi_message *msg)
787{
788 struct spi_transfer *xfer;
Mark Brownb1589352013-10-05 11:50:40 +0100789 bool keep_cs = false;
790 int ret = 0;
Mark Brown16a0ce42014-01-30 22:16:41 +0000791 int ms = 1;
Mark Brownb1589352013-10-05 11:50:40 +0100792
793 spi_set_cs(msg->spi, true);
794
795 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
796 trace_spi_transfer_start(msg, xfer);
797
Mark Brown38ec10f2014-08-16 16:27:41 +0100798 if (xfer->tx_buf || xfer->rx_buf) {
799 reinit_completion(&master->xfer_completion);
Mark Brownb1589352013-10-05 11:50:40 +0100800
Mark Brown38ec10f2014-08-16 16:27:41 +0100801 ret = master->transfer_one(master, msg->spi, xfer);
802 if (ret < 0) {
803 dev_err(&msg->spi->dev,
804 "SPI transfer failed: %d\n", ret);
805 goto out;
806 }
Mark Brownb1589352013-10-05 11:50:40 +0100807
Mark Brown38ec10f2014-08-16 16:27:41 +0100808 if (ret > 0) {
809 ret = 0;
810 ms = xfer->len * 8 * 1000 / xfer->speed_hz;
811 ms += ms + 100; /* some tolerance */
Mark Brown16a0ce42014-01-30 22:16:41 +0000812
Mark Brown38ec10f2014-08-16 16:27:41 +0100813 ms = wait_for_completion_timeout(&master->xfer_completion,
814 msecs_to_jiffies(ms));
815 }
Mark Brown16a0ce42014-01-30 22:16:41 +0000816
Mark Brown38ec10f2014-08-16 16:27:41 +0100817 if (ms == 0) {
818 dev_err(&msg->spi->dev,
819 "SPI transfer timed out\n");
820 msg->status = -ETIMEDOUT;
821 }
822 } else {
823 if (xfer->len)
824 dev_err(&msg->spi->dev,
825 "Bufferless transfer has length %u\n",
826 xfer->len);
Axel Lin13a42792014-01-18 22:05:22 +0800827 }
Mark Brownb1589352013-10-05 11:50:40 +0100828
829 trace_spi_transfer_stop(msg, xfer);
830
831 if (msg->status != -EINPROGRESS)
832 goto out;
833
834 if (xfer->delay_usecs)
835 udelay(xfer->delay_usecs);
836
837 if (xfer->cs_change) {
838 if (list_is_last(&xfer->transfer_list,
839 &msg->transfers)) {
840 keep_cs = true;
841 } else {
Mark Brown0b73aa62014-03-29 23:48:07 +0000842 spi_set_cs(msg->spi, false);
843 udelay(10);
844 spi_set_cs(msg->spi, true);
Mark Brownb1589352013-10-05 11:50:40 +0100845 }
846 }
847
848 msg->actual_length += xfer->len;
849 }
850
851out:
852 if (ret != 0 || !keep_cs)
853 spi_set_cs(msg->spi, false);
854
855 if (msg->status == -EINPROGRESS)
856 msg->status = ret;
857
858 spi_finalize_current_message(master);
859
860 return ret;
861}
862
863/**
864 * spi_finalize_current_transfer - report completion of a transfer
Thierry Reding2c675682014-08-08 13:02:36 +0200865 * @master: the master reporting completion
Mark Brownb1589352013-10-05 11:50:40 +0100866 *
867 * Called by SPI drivers using the core transfer_one_message()
868 * implementation to notify it that the current interrupt driven
Geert Uytterhoeven9e8f4882014-01-21 16:10:05 +0100869 * transfer has finished and the next one may be scheduled.
Mark Brownb1589352013-10-05 11:50:40 +0100870 */
871void spi_finalize_current_transfer(struct spi_master *master)
872{
873 complete(&master->xfer_completion);
874}
875EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
876
Linus Walleijffbbdd212012-02-22 10:05:38 +0100877/**
878 * spi_pump_messages - kthread work function which processes spi message queue
879 * @work: pointer to kthread work struct contained in the master struct
880 *
881 * This function checks if there is any spi message in the queue that
882 * needs processing and if so call out to the driver to initialize hardware
883 * and transfer each message.
884 *
885 */
886static void spi_pump_messages(struct kthread_work *work)
887{
888 struct spi_master *master =
889 container_of(work, struct spi_master, pump_messages);
890 unsigned long flags;
891 bool was_busy = false;
892 int ret;
893
894 /* Lock queue and check for queue work */
895 spin_lock_irqsave(&master->queue_lock, flags);
896 if (list_empty(&master->queue) || !master->running) {
Bryan Freedb0b36b82013-03-13 11:17:40 -0700897 if (!master->busy) {
898 spin_unlock_irqrestore(&master->queue_lock, flags);
899 return;
Linus Walleijffbbdd212012-02-22 10:05:38 +0100900 }
901 master->busy = false;
902 spin_unlock_irqrestore(&master->queue_lock, flags);
Mark Brown3a2eba92014-01-28 20:17:03 +0000903 kfree(master->dummy_rx);
904 master->dummy_rx = NULL;
905 kfree(master->dummy_tx);
906 master->dummy_tx = NULL;
Bryan Freedb0b36b82013-03-13 11:17:40 -0700907 if (master->unprepare_transfer_hardware &&
908 master->unprepare_transfer_hardware(master))
909 dev_err(&master->dev,
910 "failed to unprepare transfer hardware\n");
Mark Brown49834de2013-07-28 14:47:02 +0100911 if (master->auto_runtime_pm) {
912 pm_runtime_mark_last_busy(master->dev.parent);
913 pm_runtime_put_autosuspend(master->dev.parent);
914 }
Mark Brown56ec1972013-10-07 19:33:53 +0100915 trace_spi_master_idle(master);
Linus Walleijffbbdd212012-02-22 10:05:38 +0100916 return;
917 }
918
919 /* Make sure we are not already running a message */
920 if (master->cur_msg) {
921 spin_unlock_irqrestore(&master->queue_lock, flags);
922 return;
923 }
924 /* Extract head of queue */
925 master->cur_msg =
Axel Lina89e2d22014-01-09 16:03:58 +0800926 list_first_entry(&master->queue, struct spi_message, queue);
Linus Walleijffbbdd212012-02-22 10:05:38 +0100927
928 list_del_init(&master->cur_msg->queue);
929 if (master->busy)
930 was_busy = true;
931 else
932 master->busy = true;
933 spin_unlock_irqrestore(&master->queue_lock, flags);
934
Mark Brown49834de2013-07-28 14:47:02 +0100935 if (!was_busy && master->auto_runtime_pm) {
936 ret = pm_runtime_get_sync(master->dev.parent);
937 if (ret < 0) {
938 dev_err(&master->dev, "Failed to power device: %d\n",
939 ret);
940 return;
941 }
942 }
943
Mark Brown56ec1972013-10-07 19:33:53 +0100944 if (!was_busy)
945 trace_spi_master_busy(master);
946
Shubhrajyoti D7dfd2bd2012-05-10 19:20:41 +0530947 if (!was_busy && master->prepare_transfer_hardware) {
Linus Walleijffbbdd212012-02-22 10:05:38 +0100948 ret = master->prepare_transfer_hardware(master);
949 if (ret) {
950 dev_err(&master->dev,
951 "failed to prepare transfer hardware\n");
Mark Brown49834de2013-07-28 14:47:02 +0100952
953 if (master->auto_runtime_pm)
954 pm_runtime_put(master->dev.parent);
Linus Walleijffbbdd212012-02-22 10:05:38 +0100955 return;
956 }
957 }
958
Mark Brown56ec1972013-10-07 19:33:53 +0100959 trace_spi_message_start(master->cur_msg);
960
Mark Brown2841a5f2013-10-05 00:23:12 +0100961 if (master->prepare_message) {
962 ret = master->prepare_message(master, master->cur_msg);
963 if (ret) {
964 dev_err(&master->dev,
965 "failed to prepare message: %d\n", ret);
966 master->cur_msg->status = ret;
967 spi_finalize_current_message(master);
968 return;
969 }
970 master->cur_msg_prepared = true;
971 }
972
Mark Brown99adef32014-01-16 12:22:43 +0000973 ret = spi_map_msg(master, master->cur_msg);
974 if (ret) {
975 master->cur_msg->status = ret;
976 spi_finalize_current_message(master);
977 return;
978 }
979
Linus Walleijffbbdd212012-02-22 10:05:38 +0100980 ret = master->transfer_one_message(master, master->cur_msg);
981 if (ret) {
982 dev_err(&master->dev,
Geert Uytterhoeven1f802f82014-01-28 10:33:03 +0100983 "failed to transfer one message from queue\n");
Linus Walleijffbbdd212012-02-22 10:05:38 +0100984 return;
985 }
986}
987
988static int spi_init_queue(struct spi_master *master)
989{
990 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
991
992 INIT_LIST_HEAD(&master->queue);
993 spin_lock_init(&master->queue_lock);
994
995 master->running = false;
996 master->busy = false;
997
998 init_kthread_worker(&master->kworker);
999 master->kworker_task = kthread_run(kthread_worker_fn,
Kees Cookf1701682013-07-03 15:04:58 -07001000 &master->kworker, "%s",
Linus Walleijffbbdd212012-02-22 10:05:38 +01001001 dev_name(&master->dev));
1002 if (IS_ERR(master->kworker_task)) {
1003 dev_err(&master->dev, "failed to create message pump task\n");
1004 return -ENOMEM;
1005 }
1006 init_kthread_work(&master->pump_messages, spi_pump_messages);
1007
1008 /*
1009 * Master config will indicate if this controller should run the
1010 * message pump with high (realtime) priority to reduce the transfer
1011 * latency on the bus by minimising the delay between a transfer
1012 * request and the scheduling of the message pump thread. Without this
1013 * setting the message pump thread will remain at default priority.
1014 */
1015 if (master->rt) {
1016 dev_info(&master->dev,
1017 "will run message pump with realtime priority\n");
1018 sched_setscheduler(master->kworker_task, SCHED_FIFO, &param);
1019 }
1020
1021 return 0;
1022}
1023
1024/**
1025 * spi_get_next_queued_message() - called by driver to check for queued
1026 * messages
1027 * @master: the master to check for queued messages
1028 *
1029 * If there are more messages in the queue, the next message is returned from
1030 * this call.
1031 */
1032struct spi_message *spi_get_next_queued_message(struct spi_master *master)
1033{
1034 struct spi_message *next;
1035 unsigned long flags;
1036
1037 /* get a pointer to the next message, if any */
1038 spin_lock_irqsave(&master->queue_lock, flags);
Axel Lin1cfd97f2014-01-02 15:16:40 +08001039 next = list_first_entry_or_null(&master->queue, struct spi_message,
1040 queue);
Linus Walleijffbbdd212012-02-22 10:05:38 +01001041 spin_unlock_irqrestore(&master->queue_lock, flags);
1042
1043 return next;
1044}
1045EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1046
1047/**
1048 * spi_finalize_current_message() - the current message is complete
1049 * @master: the master to return the message to
1050 *
1051 * Called by the driver to notify the core that the message in the front of the
1052 * queue is complete and can be removed from the queue.
1053 */
1054void spi_finalize_current_message(struct spi_master *master)
1055{
1056 struct spi_message *mesg;
1057 unsigned long flags;
Mark Brown2841a5f2013-10-05 00:23:12 +01001058 int ret;
Linus Walleijffbbdd212012-02-22 10:05:38 +01001059
1060 spin_lock_irqsave(&master->queue_lock, flags);
1061 mesg = master->cur_msg;
1062 master->cur_msg = NULL;
1063
1064 queue_kthread_work(&master->kworker, &master->pump_messages);
1065 spin_unlock_irqrestore(&master->queue_lock, flags);
1066
Mark Brown99adef32014-01-16 12:22:43 +00001067 spi_unmap_msg(master, mesg);
1068
Mark Brown2841a5f2013-10-05 00:23:12 +01001069 if (master->cur_msg_prepared && master->unprepare_message) {
1070 ret = master->unprepare_message(master, mesg);
1071 if (ret) {
1072 dev_err(&master->dev,
1073 "failed to unprepare message: %d\n", ret);
1074 }
1075 }
1076 master->cur_msg_prepared = false;
1077
Linus Walleijffbbdd212012-02-22 10:05:38 +01001078 mesg->state = NULL;
1079 if (mesg->complete)
1080 mesg->complete(mesg->context);
Mark Brown56ec1972013-10-07 19:33:53 +01001081
1082 trace_spi_message_done(mesg);
Linus Walleijffbbdd212012-02-22 10:05:38 +01001083}
1084EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1085
1086static int spi_start_queue(struct spi_master *master)
1087{
1088 unsigned long flags;
1089
1090 spin_lock_irqsave(&master->queue_lock, flags);
1091
1092 if (master->running || master->busy) {
1093 spin_unlock_irqrestore(&master->queue_lock, flags);
1094 return -EBUSY;
1095 }
1096
1097 master->running = true;
1098 master->cur_msg = NULL;
1099 spin_unlock_irqrestore(&master->queue_lock, flags);
1100
1101 queue_kthread_work(&master->kworker, &master->pump_messages);
1102
1103 return 0;
1104}
1105
1106static int spi_stop_queue(struct spi_master *master)
1107{
1108 unsigned long flags;
1109 unsigned limit = 500;
1110 int ret = 0;
1111
1112 spin_lock_irqsave(&master->queue_lock, flags);
1113
1114 /*
1115 * This is a bit lame, but is optimized for the common execution path.
1116 * A wait_queue on the master->busy could be used, but then the common
1117 * execution path (pump_messages) would be required to call wake_up or
1118 * friends on every SPI message. Do this instead.
1119 */
1120 while ((!list_empty(&master->queue) || master->busy) && limit--) {
1121 spin_unlock_irqrestore(&master->queue_lock, flags);
Axel Linf97b26b2014-02-21 09:15:18 +08001122 usleep_range(10000, 11000);
Linus Walleijffbbdd212012-02-22 10:05:38 +01001123 spin_lock_irqsave(&master->queue_lock, flags);
1124 }
1125
1126 if (!list_empty(&master->queue) || master->busy)
1127 ret = -EBUSY;
1128 else
1129 master->running = false;
1130
1131 spin_unlock_irqrestore(&master->queue_lock, flags);
1132
1133 if (ret) {
1134 dev_warn(&master->dev,
1135 "could not stop message queue\n");
1136 return ret;
1137 }
1138 return ret;
1139}
1140
1141static int spi_destroy_queue(struct spi_master *master)
1142{
1143 int ret;
1144
1145 ret = spi_stop_queue(master);
1146
1147 /*
1148 * flush_kthread_worker will block until all work is done.
1149 * If the reason that stop_queue timed out is that the work will never
1150 * finish, then it does no good to call flush/stop thread, so
1151 * return anyway.
1152 */
1153 if (ret) {
1154 dev_err(&master->dev, "problem destroying queue\n");
1155 return ret;
1156 }
1157
1158 flush_kthread_worker(&master->kworker);
1159 kthread_stop(master->kworker_task);
1160
1161 return 0;
1162}
1163
1164/**
1165 * spi_queued_transfer - transfer function for queued transfers
1166 * @spi: spi device which is requesting transfer
1167 * @msg: spi message which is to handled is queued to driver queue
1168 */
1169static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1170{
1171 struct spi_master *master = spi->master;
1172 unsigned long flags;
1173
1174 spin_lock_irqsave(&master->queue_lock, flags);
1175
1176 if (!master->running) {
1177 spin_unlock_irqrestore(&master->queue_lock, flags);
1178 return -ESHUTDOWN;
1179 }
1180 msg->actual_length = 0;
1181 msg->status = -EINPROGRESS;
1182
1183 list_add_tail(&msg->queue, &master->queue);
Axel Lin96b3eac2013-08-22 23:41:34 +08001184 if (!master->busy)
Linus Walleijffbbdd212012-02-22 10:05:38 +01001185 queue_kthread_work(&master->kworker, &master->pump_messages);
1186
1187 spin_unlock_irqrestore(&master->queue_lock, flags);
1188 return 0;
1189}
1190
1191static int spi_master_initialize_queue(struct spi_master *master)
1192{
1193 int ret;
1194
Linus Walleijffbbdd212012-02-22 10:05:38 +01001195 master->transfer = spi_queued_transfer;
Mark Brownb1589352013-10-05 11:50:40 +01001196 if (!master->transfer_one_message)
1197 master->transfer_one_message = spi_transfer_one_message;
Linus Walleijffbbdd212012-02-22 10:05:38 +01001198
1199 /* Initialize and start queue */
1200 ret = spi_init_queue(master);
1201 if (ret) {
1202 dev_err(&master->dev, "problem initializing queue\n");
1203 goto err_init_queue;
1204 }
Mark Brownc3676d52014-05-01 10:47:52 -07001205 master->queued = true;
Linus Walleijffbbdd212012-02-22 10:05:38 +01001206 ret = spi_start_queue(master);
1207 if (ret) {
1208 dev_err(&master->dev, "problem starting queue\n");
1209 goto err_start_queue;
1210 }
1211
1212 return 0;
1213
1214err_start_queue:
Linus Walleijffbbdd212012-02-22 10:05:38 +01001215 spi_destroy_queue(master);
Mark Brownc3676d52014-05-01 10:47:52 -07001216err_init_queue:
Linus Walleijffbbdd212012-02-22 10:05:38 +01001217 return ret;
1218}
1219
1220/*-------------------------------------------------------------------------*/
1221
Andreas Larsson7cb94362012-12-04 15:09:38 +01001222#if defined(CONFIG_OF)
Grant Likelyd57a4282012-04-07 14:16:53 -06001223/**
1224 * of_register_spi_devices() - Register child devices onto the SPI bus
1225 * @master: Pointer to spi_master device
1226 *
1227 * Registers an spi_device for each child node of master node which has a 'reg'
1228 * property.
1229 */
1230static void of_register_spi_devices(struct spi_master *master)
1231{
1232 struct spi_device *spi;
1233 struct device_node *nc;
Grant Likelyd57a4282012-04-07 14:16:53 -06001234 int rc;
Trent Piepho89da4292013-09-27 05:37:25 -07001235 u32 value;
Grant Likelyd57a4282012-04-07 14:16:53 -06001236
1237 if (!master->dev.of_node)
1238 return;
1239
Alexander Sverdlinf3b61592012-11-29 08:59:29 +01001240 for_each_available_child_of_node(master->dev.of_node, nc) {
Grant Likelyd57a4282012-04-07 14:16:53 -06001241 /* Alloc an spi_device */
1242 spi = spi_alloc_device(master);
1243 if (!spi) {
1244 dev_err(&master->dev, "spi_device alloc error for %s\n",
1245 nc->full_name);
1246 spi_dev_put(spi);
1247 continue;
1248 }
1249
1250 /* Select device driver */
1251 if (of_modalias_node(nc, spi->modalias,
1252 sizeof(spi->modalias)) < 0) {
1253 dev_err(&master->dev, "cannot find modalias for %s\n",
1254 nc->full_name);
1255 spi_dev_put(spi);
1256 continue;
1257 }
1258
1259 /* Device address */
Trent Piepho89da4292013-09-27 05:37:25 -07001260 rc = of_property_read_u32(nc, "reg", &value);
1261 if (rc) {
1262 dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
1263 nc->full_name, rc);
Grant Likelyd57a4282012-04-07 14:16:53 -06001264 spi_dev_put(spi);
1265 continue;
1266 }
Trent Piepho89da4292013-09-27 05:37:25 -07001267 spi->chip_select = value;
Grant Likelyd57a4282012-04-07 14:16:53 -06001268
1269 /* Mode (clock phase/polarity/etc.) */
1270 if (of_find_property(nc, "spi-cpha", NULL))
1271 spi->mode |= SPI_CPHA;
1272 if (of_find_property(nc, "spi-cpol", NULL))
1273 spi->mode |= SPI_CPOL;
1274 if (of_find_property(nc, "spi-cs-high", NULL))
1275 spi->mode |= SPI_CS_HIGH;
Lars-Peter Clausenc20151d2012-12-06 16:55:33 +01001276 if (of_find_property(nc, "spi-3wire", NULL))
1277 spi->mode |= SPI_3WIRE;
Zhao Qiangcd6339e2014-04-01 17:10:50 +08001278 if (of_find_property(nc, "spi-lsb-first", NULL))
1279 spi->mode |= SPI_LSB_FIRST;
Grant Likelyd57a4282012-04-07 14:16:53 -06001280
wangyuhangf477b7f2013-08-11 18:15:17 +08001281 /* Device DUAL/QUAD mode */
Trent Piepho89da4292013-09-27 05:37:25 -07001282 if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1283 switch (value) {
1284 case 1:
Mark Browna822e992013-08-30 23:19:40 +01001285 break;
Trent Piepho89da4292013-09-27 05:37:25 -07001286 case 2:
Mark Browna822e992013-08-30 23:19:40 +01001287 spi->mode |= SPI_TX_DUAL;
1288 break;
Trent Piepho89da4292013-09-27 05:37:25 -07001289 case 4:
Mark Browna822e992013-08-30 23:19:40 +01001290 spi->mode |= SPI_TX_QUAD;
1291 break;
1292 default:
Geert Uytterhoeven80874d82014-05-26 14:05:25 +02001293 dev_warn(&master->dev,
1294 "spi-tx-bus-width %d not supported\n",
1295 value);
1296 break;
Mark Browna822e992013-08-30 23:19:40 +01001297 }
wangyuhangf477b7f2013-08-11 18:15:17 +08001298 }
1299
Trent Piepho89da4292013-09-27 05:37:25 -07001300 if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1301 switch (value) {
1302 case 1:
Mark Browna822e992013-08-30 23:19:40 +01001303 break;
Trent Piepho89da4292013-09-27 05:37:25 -07001304 case 2:
Mark Browna822e992013-08-30 23:19:40 +01001305 spi->mode |= SPI_RX_DUAL;
1306 break;
Trent Piepho89da4292013-09-27 05:37:25 -07001307 case 4:
Mark Browna822e992013-08-30 23:19:40 +01001308 spi->mode |= SPI_RX_QUAD;
1309 break;
1310 default:
Geert Uytterhoeven80874d82014-05-26 14:05:25 +02001311 dev_warn(&master->dev,
1312 "spi-rx-bus-width %d not supported\n",
1313 value);
1314 break;
Mark Browna822e992013-08-30 23:19:40 +01001315 }
wangyuhangf477b7f2013-08-11 18:15:17 +08001316 }
1317
Grant Likelyd57a4282012-04-07 14:16:53 -06001318 /* Device speed */
Trent Piepho89da4292013-09-27 05:37:25 -07001319 rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1320 if (rc) {
1321 dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
1322 nc->full_name, rc);
Grant Likelyd57a4282012-04-07 14:16:53 -06001323 spi_dev_put(spi);
1324 continue;
1325 }
Trent Piepho89da4292013-09-27 05:37:25 -07001326 spi->max_speed_hz = value;
Grant Likelyd57a4282012-04-07 14:16:53 -06001327
1328 /* IRQ */
1329 spi->irq = irq_of_parse_and_map(nc, 0);
1330
1331 /* Store a pointer to the node in the device structure */
1332 of_node_get(nc);
1333 spi->dev.of_node = nc;
1334
1335 /* Register the new device */
Mathias Krause70fac172013-08-31 20:24:14 +02001336 request_module("%s%s", SPI_MODULE_PREFIX, spi->modalias);
Grant Likelyd57a4282012-04-07 14:16:53 -06001337 rc = spi_add_device(spi);
1338 if (rc) {
1339 dev_err(&master->dev, "spi_device register error %s\n",
1340 nc->full_name);
1341 spi_dev_put(spi);
1342 }
1343
1344 }
1345}
1346#else
1347static void of_register_spi_devices(struct spi_master *master) { }
1348#endif
1349
Mika Westerberg64bee4d2012-11-30 12:37:53 +01001350#ifdef CONFIG_ACPI
1351static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1352{
1353 struct spi_device *spi = data;
1354
1355 if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1356 struct acpi_resource_spi_serialbus *sb;
1357
1358 sb = &ares->data.spi_serial_bus;
1359 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1360 spi->chip_select = sb->device_selection;
1361 spi->max_speed_hz = sb->connection_speed;
1362
1363 if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1364 spi->mode |= SPI_CPHA;
1365 if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1366 spi->mode |= SPI_CPOL;
1367 if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1368 spi->mode |= SPI_CS_HIGH;
1369 }
1370 } else if (spi->irq < 0) {
1371 struct resource r;
1372
1373 if (acpi_dev_resource_interrupt(ares, 0, &r))
1374 spi->irq = r.start;
1375 }
1376
1377 /* Always tell the ACPI core to skip this resource */
1378 return 1;
1379}
1380
1381static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1382 void *data, void **return_value)
1383{
1384 struct spi_master *master = data;
1385 struct list_head resource_list;
1386 struct acpi_device *adev;
1387 struct spi_device *spi;
1388 int ret;
1389
1390 if (acpi_bus_get_device(handle, &adev))
1391 return AE_OK;
1392 if (acpi_bus_get_status(adev) || !adev->status.present)
1393 return AE_OK;
1394
1395 spi = spi_alloc_device(master);
1396 if (!spi) {
1397 dev_err(&master->dev, "failed to allocate SPI device for %s\n",
1398 dev_name(&adev->dev));
1399 return AE_NO_MEMORY;
1400 }
1401
Rafael J. Wysocki7b199812013-11-11 22:41:56 +01001402 ACPI_COMPANION_SET(&spi->dev, adev);
Mika Westerberg64bee4d2012-11-30 12:37:53 +01001403 spi->irq = -1;
1404
1405 INIT_LIST_HEAD(&resource_list);
1406 ret = acpi_dev_get_resources(adev, &resource_list,
1407 acpi_spi_add_resource, spi);
1408 acpi_dev_free_resource_list(&resource_list);
1409
1410 if (ret < 0 || !spi->max_speed_hz) {
1411 spi_dev_put(spi);
1412 return AE_OK;
1413 }
1414
Mika Westerberg33cf00e2013-10-10 13:28:48 +03001415 adev->power.flags.ignore_parent = true;
Jarkko Nikulacf9eb392013-10-10 17:19:17 +03001416 strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias));
Mika Westerberg64bee4d2012-11-30 12:37:53 +01001417 if (spi_add_device(spi)) {
Mika Westerberg33cf00e2013-10-10 13:28:48 +03001418 adev->power.flags.ignore_parent = false;
Mika Westerberg64bee4d2012-11-30 12:37:53 +01001419 dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
1420 dev_name(&adev->dev));
1421 spi_dev_put(spi);
1422 }
1423
1424 return AE_OK;
1425}
1426
1427static void acpi_register_spi_devices(struct spi_master *master)
1428{
1429 acpi_status status;
1430 acpi_handle handle;
1431
Rafael J. Wysocki29896172013-04-01 00:21:08 +00001432 handle = ACPI_HANDLE(master->dev.parent);
Mika Westerberg64bee4d2012-11-30 12:37:53 +01001433 if (!handle)
1434 return;
1435
1436 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1437 acpi_spi_add_device, NULL,
1438 master, NULL);
1439 if (ACPI_FAILURE(status))
1440 dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
1441}
1442#else
1443static inline void acpi_register_spi_devices(struct spi_master *master) {}
1444#endif /* CONFIG_ACPI */
1445
Tony Jones49dce682007-10-16 01:27:48 -07001446static void spi_master_release(struct device *dev)
David Brownell8ae12a02006-01-08 13:34:19 -08001447{
1448 struct spi_master *master;
1449
Tony Jones49dce682007-10-16 01:27:48 -07001450 master = container_of(dev, struct spi_master, dev);
David Brownell8ae12a02006-01-08 13:34:19 -08001451 kfree(master);
1452}
1453
1454static struct class spi_master_class = {
1455 .name = "spi_master",
1456 .owner = THIS_MODULE,
Tony Jones49dce682007-10-16 01:27:48 -07001457 .dev_release = spi_master_release,
David Brownell8ae12a02006-01-08 13:34:19 -08001458};
1459
1460
Linus Walleijffbbdd212012-02-22 10:05:38 +01001461
David Brownell8ae12a02006-01-08 13:34:19 -08001462/**
1463 * spi_alloc_master - allocate SPI master controller
1464 * @dev: the controller, possibly using the platform_bus
David Brownell33e34dc2007-05-08 00:32:21 -07001465 * @size: how much zeroed driver-private data to allocate; the pointer to this
Tony Jones49dce682007-10-16 01:27:48 -07001466 * memory is in the driver_data field of the returned device,
David Brownell0c868462006-01-08 13:34:25 -08001467 * accessible with spi_master_get_devdata().
David Brownell33e34dc2007-05-08 00:32:21 -07001468 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -08001469 *
1470 * This call is used only by SPI master controller drivers, which are the
1471 * only ones directly touching chip registers. It's how they allocate
dmitry pervushinba1a0512006-05-20 15:00:14 -07001472 * an spi_master structure, prior to calling spi_register_master().
David Brownell8ae12a02006-01-08 13:34:19 -08001473 *
1474 * This must be called from context that can sleep. It returns the SPI
1475 * master structure on success, else NULL.
1476 *
1477 * The caller is responsible for assigning the bus number and initializing
dmitry pervushinba1a0512006-05-20 15:00:14 -07001478 * the master's methods before calling spi_register_master(); and (after errors
Uwe Kleine-Königeb4af0f2012-02-23 10:40:14 +01001479 * adding the device) calling spi_master_put() and kfree() to prevent a memory
1480 * leak.
David Brownell8ae12a02006-01-08 13:34:19 -08001481 */
Adrian Bunke9d5a462007-03-26 21:32:23 -08001482struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
David Brownell8ae12a02006-01-08 13:34:19 -08001483{
1484 struct spi_master *master;
1485
David Brownell0c868462006-01-08 13:34:25 -08001486 if (!dev)
1487 return NULL;
1488
Jingoo Han5fe5f052013-10-14 10:31:51 +09001489 master = kzalloc(size + sizeof(*master), GFP_KERNEL);
David Brownell8ae12a02006-01-08 13:34:19 -08001490 if (!master)
1491 return NULL;
1492
Tony Jones49dce682007-10-16 01:27:48 -07001493 device_initialize(&master->dev);
Grant Likely1e8a52e2012-05-19 23:42:08 -06001494 master->bus_num = -1;
1495 master->num_chipselect = 1;
Tony Jones49dce682007-10-16 01:27:48 -07001496 master->dev.class = &spi_master_class;
1497 master->dev.parent = get_device(dev);
David Brownell0c868462006-01-08 13:34:25 -08001498 spi_master_set_devdata(master, &master[1]);
David Brownell8ae12a02006-01-08 13:34:19 -08001499
1500 return master;
1501}
1502EXPORT_SYMBOL_GPL(spi_alloc_master);
1503
Jean-Christophe PLAGNIOL-VILLARD74317982012-11-15 20:19:57 +01001504#ifdef CONFIG_OF
1505static int of_spi_register_master(struct spi_master *master)
1506{
Grant Likelye80beb22013-02-12 17:48:37 +00001507 int nb, i, *cs;
Jean-Christophe PLAGNIOL-VILLARD74317982012-11-15 20:19:57 +01001508 struct device_node *np = master->dev.of_node;
1509
1510 if (!np)
1511 return 0;
1512
1513 nb = of_gpio_named_count(np, "cs-gpios");
Jingoo Han5fe5f052013-10-14 10:31:51 +09001514 master->num_chipselect = max_t(int, nb, master->num_chipselect);
Jean-Christophe PLAGNIOL-VILLARD74317982012-11-15 20:19:57 +01001515
Andreas Larsson8ec5d842013-02-13 14:23:24 +01001516 /* Return error only for an incorrectly formed cs-gpios property */
1517 if (nb == 0 || nb == -ENOENT)
Jean-Christophe PLAGNIOL-VILLARD74317982012-11-15 20:19:57 +01001518 return 0;
Andreas Larsson8ec5d842013-02-13 14:23:24 +01001519 else if (nb < 0)
1520 return nb;
Jean-Christophe PLAGNIOL-VILLARD74317982012-11-15 20:19:57 +01001521
1522 cs = devm_kzalloc(&master->dev,
1523 sizeof(int) * master->num_chipselect,
1524 GFP_KERNEL);
1525 master->cs_gpios = cs;
1526
1527 if (!master->cs_gpios)
1528 return -ENOMEM;
1529
Andreas Larsson0da83bb2013-01-29 15:53:40 +01001530 for (i = 0; i < master->num_chipselect; i++)
Andreas Larsson446411e2013-02-13 14:20:25 +01001531 cs[i] = -ENOENT;
Jean-Christophe PLAGNIOL-VILLARD74317982012-11-15 20:19:57 +01001532
1533 for (i = 0; i < nb; i++)
1534 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
1535
1536 return 0;
1537}
1538#else
1539static int of_spi_register_master(struct spi_master *master)
1540{
1541 return 0;
1542}
1543#endif
1544
David Brownell8ae12a02006-01-08 13:34:19 -08001545/**
1546 * spi_register_master - register SPI master controller
1547 * @master: initialized master, originally from spi_alloc_master()
David Brownell33e34dc2007-05-08 00:32:21 -07001548 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -08001549 *
1550 * SPI master controllers connect to their drivers using some non-SPI bus,
1551 * such as the platform bus. The final stage of probe() in that code
1552 * includes calling spi_register_master() to hook up to this SPI bus glue.
1553 *
1554 * SPI controllers use board specific (often SOC specific) bus numbers,
1555 * and board-specific addressing for SPI devices combines those numbers
1556 * with chip select numbers. Since SPI does not directly support dynamic
1557 * device identification, boards need configuration tables telling which
1558 * chip is at which address.
1559 *
1560 * This must be called from context that can sleep. It returns zero on
1561 * success, else a negative error code (dropping the master's refcount).
David Brownell0c868462006-01-08 13:34:25 -08001562 * After a successful return, the caller is responsible for calling
1563 * spi_unregister_master().
David Brownell8ae12a02006-01-08 13:34:19 -08001564 */
Adrian Bunke9d5a462007-03-26 21:32:23 -08001565int spi_register_master(struct spi_master *master)
David Brownell8ae12a02006-01-08 13:34:19 -08001566{
David Brownelle44a45a2007-06-03 13:50:40 -07001567 static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
Tony Jones49dce682007-10-16 01:27:48 -07001568 struct device *dev = master->dev.parent;
Feng Tang2b9603a2010-08-02 15:52:15 +08001569 struct boardinfo *bi;
David Brownell8ae12a02006-01-08 13:34:19 -08001570 int status = -ENODEV;
1571 int dynamic = 0;
1572
David Brownell0c868462006-01-08 13:34:25 -08001573 if (!dev)
1574 return -ENODEV;
1575
Jean-Christophe PLAGNIOL-VILLARD74317982012-11-15 20:19:57 +01001576 status = of_spi_register_master(master);
1577 if (status)
1578 return status;
1579
David Brownell082c8cb2007-07-31 00:39:45 -07001580 /* even if it's just one always-selected device, there must
1581 * be at least one chipselect
1582 */
1583 if (master->num_chipselect == 0)
1584 return -EINVAL;
1585
Grant Likelybb297852012-12-21 19:32:09 +00001586 if ((master->bus_num < 0) && master->dev.of_node)
1587 master->bus_num = of_alias_get_id(master->dev.of_node, "spi");
1588
David Brownell8ae12a02006-01-08 13:34:19 -08001589 /* convention: dynamically assigned bus IDs count down from the max */
David Brownella020ed72006-04-03 15:49:04 -07001590 if (master->bus_num < 0) {
David Brownell082c8cb2007-07-31 00:39:45 -07001591 /* FIXME switch to an IDR based scheme, something like
1592 * I2C now uses, so we can't run out of "dynamic" IDs
1593 */
David Brownell8ae12a02006-01-08 13:34:19 -08001594 master->bus_num = atomic_dec_return(&dyn_bus_id);
David Brownellb8852442006-01-08 13:34:23 -08001595 dynamic = 1;
David Brownell8ae12a02006-01-08 13:34:19 -08001596 }
1597
Ernst Schwabcf32b712010-06-28 17:49:29 -07001598 spin_lock_init(&master->bus_lock_spinlock);
1599 mutex_init(&master->bus_lock_mutex);
1600 master->bus_lock_flag = 0;
Mark Brownb1589352013-10-05 11:50:40 +01001601 init_completion(&master->xfer_completion);
Mark Brown6ad45a22014-02-02 13:47:47 +00001602 if (!master->max_dma_len)
1603 master->max_dma_len = INT_MAX;
Ernst Schwabcf32b712010-06-28 17:49:29 -07001604
David Brownell8ae12a02006-01-08 13:34:19 -08001605 /* register the device, then userspace will see it.
1606 * registration fails if the bus ID is in use.
1607 */
Kay Sievers35f74fc2009-01-06 10:44:37 -08001608 dev_set_name(&master->dev, "spi%u", master->bus_num);
Tony Jones49dce682007-10-16 01:27:48 -07001609 status = device_add(&master->dev);
David Brownellb8852442006-01-08 13:34:23 -08001610 if (status < 0)
David Brownell8ae12a02006-01-08 13:34:19 -08001611 goto done;
Kay Sievers35f74fc2009-01-06 10:44:37 -08001612 dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
David Brownell8ae12a02006-01-08 13:34:19 -08001613 dynamic ? " (dynamic)" : "");
1614
Linus Walleijffbbdd212012-02-22 10:05:38 +01001615 /* If we're using a queued driver, start the queue */
1616 if (master->transfer)
1617 dev_info(dev, "master is unqueued, this is deprecated\n");
1618 else {
1619 status = spi_master_initialize_queue(master);
1620 if (status) {
Axel Line93b0722013-08-31 20:25:52 +08001621 device_del(&master->dev);
Linus Walleijffbbdd212012-02-22 10:05:38 +01001622 goto done;
1623 }
1624 }
1625
Feng Tang2b9603a2010-08-02 15:52:15 +08001626 mutex_lock(&board_lock);
1627 list_add_tail(&master->list, &spi_master_list);
1628 list_for_each_entry(bi, &board_list, list)
1629 spi_match_master_to_boardinfo(master, &bi->board_info);
1630 mutex_unlock(&board_lock);
1631
Mika Westerberg64bee4d2012-11-30 12:37:53 +01001632 /* Register devices from the device tree and ACPI */
Anatolij Gustschin12b15e82010-07-27 22:35:58 +02001633 of_register_spi_devices(master);
Mika Westerberg64bee4d2012-11-30 12:37:53 +01001634 acpi_register_spi_devices(master);
David Brownell8ae12a02006-01-08 13:34:19 -08001635done:
1636 return status;
1637}
1638EXPORT_SYMBOL_GPL(spi_register_master);
1639
Mark Brown666d5b42013-08-31 18:50:52 +01001640static void devm_spi_unregister(struct device *dev, void *res)
1641{
1642 spi_unregister_master(*(struct spi_master **)res);
1643}
1644
1645/**
1646 * dev_spi_register_master - register managed SPI master controller
1647 * @dev: device managing SPI master
1648 * @master: initialized master, originally from spi_alloc_master()
1649 * Context: can sleep
1650 *
1651 * Register a SPI device as with spi_register_master() which will
1652 * automatically be unregister
1653 */
1654int devm_spi_register_master(struct device *dev, struct spi_master *master)
1655{
1656 struct spi_master **ptr;
1657 int ret;
1658
1659 ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
1660 if (!ptr)
1661 return -ENOMEM;
1662
1663 ret = spi_register_master(master);
Stephen Warren4b928942013-11-21 16:11:15 -07001664 if (!ret) {
Mark Brown666d5b42013-08-31 18:50:52 +01001665 *ptr = master;
1666 devres_add(dev, ptr);
1667 } else {
1668 devres_free(ptr);
1669 }
1670
1671 return ret;
1672}
1673EXPORT_SYMBOL_GPL(devm_spi_register_master);
1674
David Lamparter34860082010-08-30 23:54:17 +02001675static int __unregister(struct device *dev, void *null)
David Brownell8ae12a02006-01-08 13:34:19 -08001676{
David Lamparter34860082010-08-30 23:54:17 +02001677 spi_unregister_device(to_spi_device(dev));
David Brownell8ae12a02006-01-08 13:34:19 -08001678 return 0;
1679}
1680
1681/**
1682 * spi_unregister_master - unregister SPI master controller
1683 * @master: the master being unregistered
David Brownell33e34dc2007-05-08 00:32:21 -07001684 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -08001685 *
1686 * This call is used only by SPI master controller drivers, which are the
1687 * only ones directly touching chip registers.
1688 *
1689 * This must be called from context that can sleep.
1690 */
1691void spi_unregister_master(struct spi_master *master)
1692{
Jeff Garzik89fc9a12006-12-06 20:35:35 -08001693 int dummy;
1694
Linus Walleijffbbdd212012-02-22 10:05:38 +01001695 if (master->queued) {
1696 if (spi_destroy_queue(master))
1697 dev_err(&master->dev, "queue remove failed\n");
1698 }
1699
Feng Tang2b9603a2010-08-02 15:52:15 +08001700 mutex_lock(&board_lock);
1701 list_del(&master->list);
1702 mutex_unlock(&board_lock);
1703
Sebastian Andrzej Siewior97dbf372010-12-21 17:24:31 -08001704 dummy = device_for_each_child(&master->dev, NULL, __unregister);
Tony Jones49dce682007-10-16 01:27:48 -07001705 device_unregister(&master->dev);
David Brownell8ae12a02006-01-08 13:34:19 -08001706}
1707EXPORT_SYMBOL_GPL(spi_unregister_master);
1708
Linus Walleijffbbdd212012-02-22 10:05:38 +01001709int spi_master_suspend(struct spi_master *master)
1710{
1711 int ret;
1712
1713 /* Basically no-ops for non-queued masters */
1714 if (!master->queued)
1715 return 0;
1716
1717 ret = spi_stop_queue(master);
1718 if (ret)
1719 dev_err(&master->dev, "queue stop failed\n");
1720
1721 return ret;
1722}
1723EXPORT_SYMBOL_GPL(spi_master_suspend);
1724
1725int spi_master_resume(struct spi_master *master)
1726{
1727 int ret;
1728
1729 if (!master->queued)
1730 return 0;
1731
1732 ret = spi_start_queue(master);
1733 if (ret)
1734 dev_err(&master->dev, "queue restart failed\n");
1735
1736 return ret;
1737}
1738EXPORT_SYMBOL_GPL(spi_master_resume);
1739
Michał Mirosław9f3b7952013-02-01 20:40:17 +01001740static int __spi_master_match(struct device *dev, const void *data)
Dave Young5ed2c832008-01-22 15:14:18 +08001741{
1742 struct spi_master *m;
Michał Mirosław9f3b7952013-02-01 20:40:17 +01001743 const u16 *bus_num = data;
Dave Young5ed2c832008-01-22 15:14:18 +08001744
1745 m = container_of(dev, struct spi_master, dev);
1746 return m->bus_num == *bus_num;
1747}
1748
David Brownell8ae12a02006-01-08 13:34:19 -08001749/**
1750 * spi_busnum_to_master - look up master associated with bus_num
1751 * @bus_num: the master's bus number
David Brownell33e34dc2007-05-08 00:32:21 -07001752 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -08001753 *
1754 * This call may be used with devices that are registered after
1755 * arch init time. It returns a refcounted pointer to the relevant
1756 * spi_master (which the caller must release), or NULL if there is
1757 * no such master registered.
1758 */
1759struct spi_master *spi_busnum_to_master(u16 bus_num)
1760{
Tony Jones49dce682007-10-16 01:27:48 -07001761 struct device *dev;
Atsushi Nemoto1e9a51d2007-01-26 00:56:54 -08001762 struct spi_master *master = NULL;
David Brownell8ae12a02006-01-08 13:34:19 -08001763
Greg Kroah-Hartman695794a2008-05-22 17:21:08 -04001764 dev = class_find_device(&spi_master_class, NULL, &bus_num,
Dave Young5ed2c832008-01-22 15:14:18 +08001765 __spi_master_match);
1766 if (dev)
1767 master = container_of(dev, struct spi_master, dev);
1768 /* reference got in class_find_device */
Atsushi Nemoto1e9a51d2007-01-26 00:56:54 -08001769 return master;
David Brownell8ae12a02006-01-08 13:34:19 -08001770}
1771EXPORT_SYMBOL_GPL(spi_busnum_to_master);
1772
1773
1774/*-------------------------------------------------------------------------*/
1775
David Brownell7d077192009-06-17 16:26:03 -07001776/* Core methods for SPI master protocol drivers. Some of the
1777 * other core methods are currently defined as inline functions.
1778 */
1779
1780/**
1781 * spi_setup - setup SPI mode and clock rate
1782 * @spi: the device whose settings are being modified
1783 * Context: can sleep, and no requests are queued to the device
1784 *
1785 * SPI protocol drivers may need to update the transfer mode if the
1786 * device doesn't work with its default. They may likewise need
1787 * to update clock rates or word sizes from initial values. This function
1788 * changes those settings, and must be called from a context that can sleep.
1789 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
1790 * effect the next time the device is selected and data is transferred to
1791 * or from it. When this function returns, the spi device is deselected.
1792 *
1793 * Note that this call will fail if the protocol driver specifies an option
1794 * that the underlying controller or its driver does not support. For
1795 * example, not all hardware supports wire transfers using nine bit words,
1796 * LSB-first wire encoding, or active-high chipselects.
1797 */
1798int spi_setup(struct spi_device *spi)
1799{
Geert Uytterhoeven83596fb2014-04-14 19:39:53 +02001800 unsigned bad_bits, ugly_bits;
Laxman Dewangancaae0702012-11-09 14:35:22 +05301801 int status = 0;
David Brownell7d077192009-06-17 16:26:03 -07001802
wangyuhangf477b7f2013-08-11 18:15:17 +08001803 /* check mode to prevent that DUAL and QUAD set at the same time
1804 */
1805 if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
1806 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
1807 dev_err(&spi->dev,
1808 "setup: can not select dual and quad at the same time\n");
1809 return -EINVAL;
1810 }
1811 /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
1812 */
1813 if ((spi->mode & SPI_3WIRE) && (spi->mode &
1814 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
1815 return -EINVAL;
David Brownelle7db06b2009-06-17 16:26:04 -07001816 /* help drivers fail *cleanly* when they need options
1817 * that aren't supported with their current master
1818 */
1819 bad_bits = spi->mode & ~spi->master->mode_bits;
Geert Uytterhoeven83596fb2014-04-14 19:39:53 +02001820 ugly_bits = bad_bits &
1821 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD);
1822 if (ugly_bits) {
1823 dev_warn(&spi->dev,
1824 "setup: ignoring unsupported mode bits %x\n",
1825 ugly_bits);
1826 spi->mode &= ~ugly_bits;
1827 bad_bits &= ~ugly_bits;
1828 }
David Brownelle7db06b2009-06-17 16:26:04 -07001829 if (bad_bits) {
Linus Walleijeb288a12010-10-21 21:06:44 +02001830 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
David Brownelle7db06b2009-06-17 16:26:04 -07001831 bad_bits);
1832 return -EINVAL;
1833 }
1834
David Brownell7d077192009-06-17 16:26:03 -07001835 if (!spi->bits_per_word)
1836 spi->bits_per_word = 8;
1837
Axel Lin052eb2d42014-02-10 00:08:05 +08001838 if (!spi->max_speed_hz)
1839 spi->max_speed_hz = spi->master->max_speed_hz;
1840
Laxman Dewangancaae0702012-11-09 14:35:22 +05301841 if (spi->master->setup)
1842 status = spi->master->setup(spi);
David Brownell7d077192009-06-17 16:26:03 -07001843
Jingoo Han5fe5f052013-10-14 10:31:51 +09001844 dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
David Brownell7d077192009-06-17 16:26:03 -07001845 (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
1846 (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
1847 (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
1848 (spi->mode & SPI_3WIRE) ? "3wire, " : "",
1849 (spi->mode & SPI_LOOP) ? "loopback, " : "",
1850 spi->bits_per_word, spi->max_speed_hz,
1851 status);
1852
1853 return status;
1854}
1855EXPORT_SYMBOL_GPL(spi_setup);
1856
Mark Brown90808732013-11-13 23:44:15 +00001857static int __spi_validate(struct spi_device *spi, struct spi_message *message)
Ernst Schwabcf32b712010-06-28 17:49:29 -07001858{
1859 struct spi_master *master = spi->master;
Laxman Dewangane6811d12012-11-09 14:36:45 +05301860 struct spi_transfer *xfer;
Atsushi Nemoto6ea31292014-02-28 23:03:16 +09001861 int w_size;
Ernst Schwabcf32b712010-06-28 17:49:29 -07001862
Mark Brown24a00132013-07-10 15:05:40 +01001863 if (list_empty(&message->transfers))
1864 return -EINVAL;
Mark Brown24a00132013-07-10 15:05:40 +01001865
Ernst Schwabcf32b712010-06-28 17:49:29 -07001866 /* Half-duplex links include original MicroWire, and ones with
1867 * only one data pin like SPI_3WIRE (switches direction) or where
1868 * either MOSI or MISO is missing. They can also be caused by
1869 * software limitations.
1870 */
1871 if ((master->flags & SPI_MASTER_HALF_DUPLEX)
1872 || (spi->mode & SPI_3WIRE)) {
Ernst Schwabcf32b712010-06-28 17:49:29 -07001873 unsigned flags = master->flags;
1874
1875 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1876 if (xfer->rx_buf && xfer->tx_buf)
1877 return -EINVAL;
1878 if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
1879 return -EINVAL;
1880 if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
1881 return -EINVAL;
1882 }
1883 }
1884
Laxman Dewangane6811d12012-11-09 14:36:45 +05301885 /**
Laxman Dewangan059b8ff2013-01-05 00:17:14 +05301886 * Set transfer bits_per_word and max speed as spi device default if
1887 * it is not set for this transfer.
wangyuhangf477b7f2013-08-11 18:15:17 +08001888 * Set transfer tx_nbits and rx_nbits as single transfer default
1889 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
Laxman Dewangane6811d12012-11-09 14:36:45 +05301890 */
1891 list_for_each_entry(xfer, &message->transfers, transfer_list) {
Sourav Poddar078726c2013-07-18 15:31:25 +05301892 message->frame_length += xfer->len;
Laxman Dewangane6811d12012-11-09 14:36:45 +05301893 if (!xfer->bits_per_word)
1894 xfer->bits_per_word = spi->bits_per_word;
Axel Lina6f87fa2014-03-17 10:08:12 +08001895
1896 if (!xfer->speed_hz)
Laxman Dewangan059b8ff2013-01-05 00:17:14 +05301897 xfer->speed_hz = spi->max_speed_hz;
Axel Lina6f87fa2014-03-17 10:08:12 +08001898
1899 if (master->max_speed_hz &&
1900 xfer->speed_hz > master->max_speed_hz)
1901 xfer->speed_hz = master->max_speed_hz;
Gabor Juhos56ede942013-08-14 10:25:28 +02001902
Stephen Warren543bb252013-03-26 20:37:57 -06001903 if (master->bits_per_word_mask) {
1904 /* Only 32 bits fit in the mask */
1905 if (xfer->bits_per_word > 32)
1906 return -EINVAL;
1907 if (!(master->bits_per_word_mask &
1908 BIT(xfer->bits_per_word - 1)))
1909 return -EINVAL;
1910 }
Mark Browna2fd4f92013-07-10 14:57:26 +01001911
Ivan T. Ivanov4d94bd22014-02-20 12:02:08 +02001912 /*
1913 * SPI transfer length should be multiple of SPI word size
1914 * where SPI word size should be power-of-two multiple
1915 */
1916 if (xfer->bits_per_word <= 8)
1917 w_size = 1;
1918 else if (xfer->bits_per_word <= 16)
1919 w_size = 2;
1920 else
1921 w_size = 4;
1922
Ivan T. Ivanov4d94bd22014-02-20 12:02:08 +02001923 /* No partial transfers accepted */
Atsushi Nemoto6ea31292014-02-28 23:03:16 +09001924 if (xfer->len % w_size)
Ivan T. Ivanov4d94bd22014-02-20 12:02:08 +02001925 return -EINVAL;
1926
Mark Browna2fd4f92013-07-10 14:57:26 +01001927 if (xfer->speed_hz && master->min_speed_hz &&
1928 xfer->speed_hz < master->min_speed_hz)
1929 return -EINVAL;
wangyuhangf477b7f2013-08-11 18:15:17 +08001930
1931 if (xfer->tx_buf && !xfer->tx_nbits)
1932 xfer->tx_nbits = SPI_NBITS_SINGLE;
1933 if (xfer->rx_buf && !xfer->rx_nbits)
1934 xfer->rx_nbits = SPI_NBITS_SINGLE;
1935 /* check transfer tx/rx_nbits:
Geert Uytterhoeven1afd9982014-01-12 14:00:29 +01001936 * 1. check the value matches one of single, dual and quad
1937 * 2. check tx/rx_nbits match the mode in spi_device
wangyuhangf477b7f2013-08-11 18:15:17 +08001938 */
Sourav Poddardb90a442013-08-22 21:20:48 +05301939 if (xfer->tx_buf) {
1940 if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
1941 xfer->tx_nbits != SPI_NBITS_DUAL &&
1942 xfer->tx_nbits != SPI_NBITS_QUAD)
1943 return -EINVAL;
1944 if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
1945 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
1946 return -EINVAL;
1947 if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
1948 !(spi->mode & SPI_TX_QUAD))
1949 return -EINVAL;
Sourav Poddardb90a442013-08-22 21:20:48 +05301950 }
wangyuhangf477b7f2013-08-11 18:15:17 +08001951 /* check transfer rx_nbits */
Sourav Poddardb90a442013-08-22 21:20:48 +05301952 if (xfer->rx_buf) {
1953 if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
1954 xfer->rx_nbits != SPI_NBITS_DUAL &&
1955 xfer->rx_nbits != SPI_NBITS_QUAD)
1956 return -EINVAL;
1957 if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
1958 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
1959 return -EINVAL;
1960 if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
1961 !(spi->mode & SPI_RX_QUAD))
1962 return -EINVAL;
Sourav Poddardb90a442013-08-22 21:20:48 +05301963 }
Laxman Dewangane6811d12012-11-09 14:36:45 +05301964 }
1965
Ernst Schwabcf32b712010-06-28 17:49:29 -07001966 message->status = -EINPROGRESS;
Mark Brown90808732013-11-13 23:44:15 +00001967
1968 return 0;
1969}
1970
1971static int __spi_async(struct spi_device *spi, struct spi_message *message)
1972{
1973 struct spi_master *master = spi->master;
1974
1975 message->spi = spi;
1976
1977 trace_spi_message_submit(message);
1978
Ernst Schwabcf32b712010-06-28 17:49:29 -07001979 return master->transfer(spi, message);
1980}
1981
David Brownell568d0692009-09-22 16:46:18 -07001982/**
1983 * spi_async - asynchronous SPI transfer
1984 * @spi: device with which data will be exchanged
1985 * @message: describes the data transfers, including completion callback
1986 * Context: any (irqs may be blocked, etc)
1987 *
1988 * This call may be used in_irq and other contexts which can't sleep,
1989 * as well as from task contexts which can sleep.
1990 *
1991 * The completion callback is invoked in a context which can't sleep.
1992 * Before that invocation, the value of message->status is undefined.
1993 * When the callback is issued, message->status holds either zero (to
1994 * indicate complete success) or a negative error code. After that
1995 * callback returns, the driver which issued the transfer request may
1996 * deallocate the associated memory; it's no longer in use by any SPI
1997 * core or controller driver code.
1998 *
1999 * Note that although all messages to a spi_device are handled in
2000 * FIFO order, messages may go to different devices in other orders.
2001 * Some device might be higher priority, or have various "hard" access
2002 * time requirements, for example.
2003 *
2004 * On detection of any fault during the transfer, processing of
2005 * the entire message is aborted, and the device is deselected.
2006 * Until returning from the associated message completion callback,
2007 * no other spi_message queued to that device will be processed.
2008 * (This rule applies equally to all the synchronous transfer calls,
2009 * which are wrappers around this core asynchronous primitive.)
2010 */
2011int spi_async(struct spi_device *spi, struct spi_message *message)
2012{
2013 struct spi_master *master = spi->master;
Ernst Schwabcf32b712010-06-28 17:49:29 -07002014 int ret;
2015 unsigned long flags;
David Brownell568d0692009-09-22 16:46:18 -07002016
Mark Brown90808732013-11-13 23:44:15 +00002017 ret = __spi_validate(spi, message);
2018 if (ret != 0)
2019 return ret;
2020
Ernst Schwabcf32b712010-06-28 17:49:29 -07002021 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
David Brownell568d0692009-09-22 16:46:18 -07002022
Ernst Schwabcf32b712010-06-28 17:49:29 -07002023 if (master->bus_lock_flag)
2024 ret = -EBUSY;
2025 else
2026 ret = __spi_async(spi, message);
David Brownell568d0692009-09-22 16:46:18 -07002027
Ernst Schwabcf32b712010-06-28 17:49:29 -07002028 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2029
2030 return ret;
David Brownell568d0692009-09-22 16:46:18 -07002031}
2032EXPORT_SYMBOL_GPL(spi_async);
2033
Ernst Schwabcf32b712010-06-28 17:49:29 -07002034/**
2035 * spi_async_locked - version of spi_async with exclusive bus usage
2036 * @spi: device with which data will be exchanged
2037 * @message: describes the data transfers, including completion callback
2038 * Context: any (irqs may be blocked, etc)
2039 *
2040 * This call may be used in_irq and other contexts which can't sleep,
2041 * as well as from task contexts which can sleep.
2042 *
2043 * The completion callback is invoked in a context which can't sleep.
2044 * Before that invocation, the value of message->status is undefined.
2045 * When the callback is issued, message->status holds either zero (to
2046 * indicate complete success) or a negative error code. After that
2047 * callback returns, the driver which issued the transfer request may
2048 * deallocate the associated memory; it's no longer in use by any SPI
2049 * core or controller driver code.
2050 *
2051 * Note that although all messages to a spi_device are handled in
2052 * FIFO order, messages may go to different devices in other orders.
2053 * Some device might be higher priority, or have various "hard" access
2054 * time requirements, for example.
2055 *
2056 * On detection of any fault during the transfer, processing of
2057 * the entire message is aborted, and the device is deselected.
2058 * Until returning from the associated message completion callback,
2059 * no other spi_message queued to that device will be processed.
2060 * (This rule applies equally to all the synchronous transfer calls,
2061 * which are wrappers around this core asynchronous primitive.)
2062 */
2063int spi_async_locked(struct spi_device *spi, struct spi_message *message)
2064{
2065 struct spi_master *master = spi->master;
2066 int ret;
2067 unsigned long flags;
2068
Mark Brown90808732013-11-13 23:44:15 +00002069 ret = __spi_validate(spi, message);
2070 if (ret != 0)
2071 return ret;
2072
Ernst Schwabcf32b712010-06-28 17:49:29 -07002073 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2074
2075 ret = __spi_async(spi, message);
2076
2077 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2078
2079 return ret;
2080
2081}
2082EXPORT_SYMBOL_GPL(spi_async_locked);
2083
David Brownell7d077192009-06-17 16:26:03 -07002084
2085/*-------------------------------------------------------------------------*/
2086
2087/* Utility methods for SPI master protocol drivers, layered on
2088 * top of the core. Some other utility methods are defined as
2089 * inline functions.
2090 */
2091
Andrew Morton5d870c82006-01-11 11:23:49 -08002092static void spi_complete(void *arg)
2093{
2094 complete(arg);
2095}
2096
Ernst Schwabcf32b712010-06-28 17:49:29 -07002097static int __spi_sync(struct spi_device *spi, struct spi_message *message,
2098 int bus_locked)
2099{
2100 DECLARE_COMPLETION_ONSTACK(done);
2101 int status;
2102 struct spi_master *master = spi->master;
2103
2104 message->complete = spi_complete;
2105 message->context = &done;
2106
2107 if (!bus_locked)
2108 mutex_lock(&master->bus_lock_mutex);
2109
2110 status = spi_async_locked(spi, message);
2111
2112 if (!bus_locked)
2113 mutex_unlock(&master->bus_lock_mutex);
2114
2115 if (status == 0) {
2116 wait_for_completion(&done);
2117 status = message->status;
2118 }
2119 message->context = NULL;
2120 return status;
2121}
2122
David Brownell8ae12a02006-01-08 13:34:19 -08002123/**
2124 * spi_sync - blocking/synchronous SPI data transfers
2125 * @spi: device with which data will be exchanged
2126 * @message: describes the data transfers
David Brownell33e34dc2007-05-08 00:32:21 -07002127 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -08002128 *
2129 * This call may only be used from a context that may sleep. The sleep
2130 * is non-interruptible, and has no timeout. Low-overhead controller
2131 * drivers may DMA directly into and out of the message buffers.
2132 *
2133 * Note that the SPI device's chip select is active during the message,
2134 * and then is normally disabled between messages. Drivers for some
2135 * frequently-used devices may want to minimize costs of selecting a chip,
2136 * by leaving it selected in anticipation that the next message will go
2137 * to the same chip. (That may increase power usage.)
2138 *
David Brownell0c868462006-01-08 13:34:25 -08002139 * Also, the caller is guaranteeing that the memory associated with the
2140 * message will not be freed before this call returns.
2141 *
Marc Pignat9b938b72007-12-04 23:45:10 -08002142 * It returns zero on success, else a negative error code.
David Brownell8ae12a02006-01-08 13:34:19 -08002143 */
2144int spi_sync(struct spi_device *spi, struct spi_message *message)
2145{
Ernst Schwabcf32b712010-06-28 17:49:29 -07002146 return __spi_sync(spi, message, 0);
David Brownell8ae12a02006-01-08 13:34:19 -08002147}
2148EXPORT_SYMBOL_GPL(spi_sync);
2149
Ernst Schwabcf32b712010-06-28 17:49:29 -07002150/**
2151 * spi_sync_locked - version of spi_sync with exclusive bus usage
2152 * @spi: device with which data will be exchanged
2153 * @message: describes the data transfers
2154 * Context: can sleep
2155 *
2156 * This call may only be used from a context that may sleep. The sleep
2157 * is non-interruptible, and has no timeout. Low-overhead controller
2158 * drivers may DMA directly into and out of the message buffers.
2159 *
2160 * This call should be used by drivers that require exclusive access to the
Lucas De Marchi25985ed2011-03-30 22:57:33 -03002161 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
Ernst Schwabcf32b712010-06-28 17:49:29 -07002162 * be released by a spi_bus_unlock call when the exclusive access is over.
2163 *
2164 * It returns zero on success, else a negative error code.
2165 */
2166int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
2167{
2168 return __spi_sync(spi, message, 1);
2169}
2170EXPORT_SYMBOL_GPL(spi_sync_locked);
2171
2172/**
2173 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
2174 * @master: SPI bus master that should be locked for exclusive bus access
2175 * Context: can sleep
2176 *
2177 * This call may only be used from a context that may sleep. The sleep
2178 * is non-interruptible, and has no timeout.
2179 *
2180 * This call should be used by drivers that require exclusive access to the
2181 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
2182 * exclusive access is over. Data transfer must be done by spi_sync_locked
2183 * and spi_async_locked calls when the SPI bus lock is held.
2184 *
2185 * It returns zero on success, else a negative error code.
2186 */
2187int spi_bus_lock(struct spi_master *master)
2188{
2189 unsigned long flags;
2190
2191 mutex_lock(&master->bus_lock_mutex);
2192
2193 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2194 master->bus_lock_flag = 1;
2195 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2196
2197 /* mutex remains locked until spi_bus_unlock is called */
2198
2199 return 0;
2200}
2201EXPORT_SYMBOL_GPL(spi_bus_lock);
2202
2203/**
2204 * spi_bus_unlock - release the lock for exclusive SPI bus usage
2205 * @master: SPI bus master that was locked for exclusive bus access
2206 * Context: can sleep
2207 *
2208 * This call may only be used from a context that may sleep. The sleep
2209 * is non-interruptible, and has no timeout.
2210 *
2211 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
2212 * call.
2213 *
2214 * It returns zero on success, else a negative error code.
2215 */
2216int spi_bus_unlock(struct spi_master *master)
2217{
2218 master->bus_lock_flag = 0;
2219
2220 mutex_unlock(&master->bus_lock_mutex);
2221
2222 return 0;
2223}
2224EXPORT_SYMBOL_GPL(spi_bus_unlock);
2225
David Brownella9948b62006-04-02 10:37:40 -08002226/* portable code must never pass more than 32 bytes */
Jingoo Han5fe5f052013-10-14 10:31:51 +09002227#define SPI_BUFSIZ max(32, SMP_CACHE_BYTES)
David Brownell8ae12a02006-01-08 13:34:19 -08002228
2229static u8 *buf;
2230
2231/**
2232 * spi_write_then_read - SPI synchronous write followed by read
2233 * @spi: device with which data will be exchanged
2234 * @txbuf: data to be written (need not be dma-safe)
2235 * @n_tx: size of txbuf, in bytes
Jiri Pirko27570492009-06-17 16:26:06 -07002236 * @rxbuf: buffer into which data will be read (need not be dma-safe)
2237 * @n_rx: size of rxbuf, in bytes
David Brownell33e34dc2007-05-08 00:32:21 -07002238 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -08002239 *
2240 * This performs a half duplex MicroWire style transaction with the
2241 * device, sending txbuf and then reading rxbuf. The return value
2242 * is zero for success, else a negative errno status code.
David Brownellb8852442006-01-08 13:34:23 -08002243 * This call may only be used from a context that may sleep.
David Brownell8ae12a02006-01-08 13:34:19 -08002244 *
David Brownell0c868462006-01-08 13:34:25 -08002245 * Parameters to this routine are always copied using a small buffer;
David Brownell33e34dc2007-05-08 00:32:21 -07002246 * portable code should never use this for more than 32 bytes.
2247 * Performance-sensitive or bulk transfer code should instead use
David Brownell0c868462006-01-08 13:34:25 -08002248 * spi_{async,sync}() calls with dma-safe buffers.
David Brownell8ae12a02006-01-08 13:34:19 -08002249 */
2250int spi_write_then_read(struct spi_device *spi,
Mark Brown0c4a1592011-05-11 00:09:30 +02002251 const void *txbuf, unsigned n_tx,
2252 void *rxbuf, unsigned n_rx)
David Brownell8ae12a02006-01-08 13:34:19 -08002253{
David Brownell068f4072007-12-04 23:45:09 -08002254 static DEFINE_MUTEX(lock);
David Brownell8ae12a02006-01-08 13:34:19 -08002255
2256 int status;
2257 struct spi_message message;
David Brownellbdff5492009-04-13 14:39:57 -07002258 struct spi_transfer x[2];
David Brownell8ae12a02006-01-08 13:34:19 -08002259 u8 *local_buf;
2260
Mark Brownb3a223e2012-12-02 12:54:25 +09002261 /* Use preallocated DMA-safe buffer if we can. We can't avoid
2262 * copying here, (as a pure convenience thing), but we can
2263 * keep heap costs out of the hot path unless someone else is
2264 * using the pre-allocated buffer or the transfer is too large.
David Brownell8ae12a02006-01-08 13:34:19 -08002265 */
Mark Brownb3a223e2012-12-02 12:54:25 +09002266 if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
Mark Brown2cd94c82013-01-27 14:35:04 +08002267 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
2268 GFP_KERNEL | GFP_DMA);
Mark Brownb3a223e2012-12-02 12:54:25 +09002269 if (!local_buf)
2270 return -ENOMEM;
2271 } else {
2272 local_buf = buf;
2273 }
David Brownell8ae12a02006-01-08 13:34:19 -08002274
Vitaly Wool8275c642006-01-08 13:34:28 -08002275 spi_message_init(&message);
Jingoo Han5fe5f052013-10-14 10:31:51 +09002276 memset(x, 0, sizeof(x));
David Brownellbdff5492009-04-13 14:39:57 -07002277 if (n_tx) {
2278 x[0].len = n_tx;
2279 spi_message_add_tail(&x[0], &message);
2280 }
2281 if (n_rx) {
2282 x[1].len = n_rx;
2283 spi_message_add_tail(&x[1], &message);
2284 }
Vitaly Wool8275c642006-01-08 13:34:28 -08002285
David Brownell8ae12a02006-01-08 13:34:19 -08002286 memcpy(local_buf, txbuf, n_tx);
David Brownellbdff5492009-04-13 14:39:57 -07002287 x[0].tx_buf = local_buf;
2288 x[1].rx_buf = local_buf + n_tx;
David Brownell8ae12a02006-01-08 13:34:19 -08002289
2290 /* do the i/o */
David Brownell8ae12a02006-01-08 13:34:19 -08002291 status = spi_sync(spi, &message);
Marc Pignat9b938b72007-12-04 23:45:10 -08002292 if (status == 0)
David Brownellbdff5492009-04-13 14:39:57 -07002293 memcpy(rxbuf, x[1].rx_buf, n_rx);
David Brownell8ae12a02006-01-08 13:34:19 -08002294
David Brownellbdff5492009-04-13 14:39:57 -07002295 if (x[0].tx_buf == buf)
David Brownell068f4072007-12-04 23:45:09 -08002296 mutex_unlock(&lock);
David Brownell8ae12a02006-01-08 13:34:19 -08002297 else
2298 kfree(local_buf);
2299
2300 return status;
2301}
2302EXPORT_SYMBOL_GPL(spi_write_then_read);
2303
2304/*-------------------------------------------------------------------------*/
2305
2306static int __init spi_init(void)
2307{
David Brownellb8852442006-01-08 13:34:23 -08002308 int status;
David Brownell8ae12a02006-01-08 13:34:19 -08002309
Christoph Lametere94b1762006-12-06 20:33:17 -08002310 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
David Brownellb8852442006-01-08 13:34:23 -08002311 if (!buf) {
2312 status = -ENOMEM;
2313 goto err0;
2314 }
2315
2316 status = bus_register(&spi_bus_type);
2317 if (status < 0)
2318 goto err1;
2319
2320 status = class_register(&spi_master_class);
2321 if (status < 0)
2322 goto err2;
David Brownell8ae12a02006-01-08 13:34:19 -08002323 return 0;
David Brownellb8852442006-01-08 13:34:23 -08002324
2325err2:
2326 bus_unregister(&spi_bus_type);
2327err1:
2328 kfree(buf);
2329 buf = NULL;
2330err0:
2331 return status;
David Brownell8ae12a02006-01-08 13:34:19 -08002332}
David Brownellb8852442006-01-08 13:34:23 -08002333
David Brownell8ae12a02006-01-08 13:34:19 -08002334/* board_info is normally registered in arch_initcall(),
2335 * but even essential drivers wait till later
David Brownellb8852442006-01-08 13:34:23 -08002336 *
2337 * REVISIT only boardinfo really needs static linking. the rest (device and
2338 * driver registration) _could_ be dynamically linked (modular) ... costs
2339 * include needing to have boardinfo data structures be much more public.
David Brownell8ae12a02006-01-08 13:34:19 -08002340 */
David Brownell673c0c02008-10-15 22:02:46 -07002341postcore_initcall(spi_init);
David Brownell8ae12a02006-01-08 13:34:19 -08002342