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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>
Matthias Kaehlcke94040822007-07-17 04:04:16 -070027#include <linux/mutex.h>
Sinan Akman2b7a32f2010-10-02 21:28:29 -060028#include <linux/of_device.h>
Grant Likelyd57a4282012-04-07 14:16:53 -060029#include <linux/of_irq.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090030#include <linux/slab.h>
Anton Vorontsove0626e32009-09-22 16:46:08 -070031#include <linux/mod_devicetable.h>
David Brownell8ae12a02006-01-08 13:34:19 -080032#include <linux/spi/spi.h>
Mark Brown3ae22e82010-12-25 15:32:27 +010033#include <linux/pm_runtime.h>
Paul Gortmaker025ed132011-07-10 12:57:55 -040034#include <linux/export.h>
Linus Walleijffbbdd212012-02-22 10:05:38 +010035#include <linux/sched.h>
36#include <linux/delay.h>
37#include <linux/kthread.h>
David Brownell8ae12a02006-01-08 13:34:19 -080038
David Brownell8ae12a02006-01-08 13:34:19 -080039static void spidev_release(struct device *dev)
40{
Hans-Peter Nilsson0ffa0282007-02-12 00:52:45 -080041 struct spi_device *spi = to_spi_device(dev);
David Brownell8ae12a02006-01-08 13:34:19 -080042
43 /* spi masters may cleanup for released devices */
44 if (spi->master->cleanup)
45 spi->master->cleanup(spi);
46
David Brownell0c868462006-01-08 13:34:25 -080047 spi_master_put(spi->master);
Roman Tereshonkov07a389f2010-04-12 09:56:35 +000048 kfree(spi);
David Brownell8ae12a02006-01-08 13:34:19 -080049}
50
51static ssize_t
52modalias_show(struct device *dev, struct device_attribute *a, char *buf)
53{
54 const struct spi_device *spi = to_spi_device(dev);
55
Grant Likelyd8e328b2012-05-20 00:08:13 -060056 return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
David Brownell8ae12a02006-01-08 13:34:19 -080057}
58
59static struct device_attribute spi_dev_attrs[] = {
60 __ATTR_RO(modalias),
61 __ATTR_NULL,
62};
63
64/* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
65 * and the sysfs version makes coldplug work too.
66 */
67
Anton Vorontsov75368bf2009-09-22 16:46:04 -070068static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
69 const struct spi_device *sdev)
70{
71 while (id->name[0]) {
72 if (!strcmp(sdev->modalias, id->name))
73 return id;
74 id++;
75 }
76 return NULL;
77}
78
79const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
80{
81 const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
82
83 return spi_match_id(sdrv->id_table, sdev);
84}
85EXPORT_SYMBOL_GPL(spi_get_device_id);
86
David Brownell8ae12a02006-01-08 13:34:19 -080087static int spi_match_device(struct device *dev, struct device_driver *drv)
88{
89 const struct spi_device *spi = to_spi_device(dev);
Anton Vorontsov75368bf2009-09-22 16:46:04 -070090 const struct spi_driver *sdrv = to_spi_driver(drv);
91
Sinan Akman2b7a32f2010-10-02 21:28:29 -060092 /* Attempt an OF style match */
93 if (of_driver_match_device(dev, drv))
94 return 1;
95
Anton Vorontsov75368bf2009-09-22 16:46:04 -070096 if (sdrv->id_table)
97 return !!spi_match_id(sdrv->id_table, spi);
David Brownell8ae12a02006-01-08 13:34:19 -080098
Kay Sievers35f74fc2009-01-06 10:44:37 -080099 return strcmp(spi->modalias, drv->name) == 0;
David Brownell8ae12a02006-01-08 13:34:19 -0800100}
101
Kay Sievers7eff2e72007-08-14 15:15:12 +0200102static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
David Brownell8ae12a02006-01-08 13:34:19 -0800103{
104 const struct spi_device *spi = to_spi_device(dev);
105
Anton Vorontsove0626e32009-09-22 16:46:08 -0700106 add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
David Brownell8ae12a02006-01-08 13:34:19 -0800107 return 0;
108}
109
Mark Brown3ae22e82010-12-25 15:32:27 +0100110#ifdef CONFIG_PM_SLEEP
111static int spi_legacy_suspend(struct device *dev, pm_message_t message)
David Brownell8ae12a02006-01-08 13:34:19 -0800112{
David Brownell3c724262008-02-06 01:38:10 -0800113 int value = 0;
David Brownellb8852442006-01-08 13:34:23 -0800114 struct spi_driver *drv = to_spi_driver(dev->driver);
David Brownell8ae12a02006-01-08 13:34:19 -0800115
David Brownell8ae12a02006-01-08 13:34:19 -0800116 /* suspend will stop irqs and dma; no more i/o */
David Brownell3c724262008-02-06 01:38:10 -0800117 if (drv) {
118 if (drv->suspend)
119 value = drv->suspend(to_spi_device(dev), message);
120 else
121 dev_dbg(dev, "... can't suspend\n");
122 }
David Brownell8ae12a02006-01-08 13:34:19 -0800123 return value;
124}
125
Mark Brown3ae22e82010-12-25 15:32:27 +0100126static int spi_legacy_resume(struct device *dev)
David Brownell8ae12a02006-01-08 13:34:19 -0800127{
David Brownell3c724262008-02-06 01:38:10 -0800128 int value = 0;
David Brownellb8852442006-01-08 13:34:23 -0800129 struct spi_driver *drv = to_spi_driver(dev->driver);
David Brownell8ae12a02006-01-08 13:34:19 -0800130
David Brownell8ae12a02006-01-08 13:34:19 -0800131 /* resume may restart the i/o queue */
David Brownell3c724262008-02-06 01:38:10 -0800132 if (drv) {
133 if (drv->resume)
134 value = drv->resume(to_spi_device(dev));
135 else
136 dev_dbg(dev, "... can't resume\n");
137 }
David Brownell8ae12a02006-01-08 13:34:19 -0800138 return value;
139}
140
Mark Brown3ae22e82010-12-25 15:32:27 +0100141static int spi_pm_suspend(struct device *dev)
142{
143 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
144
145 if (pm)
146 return pm_generic_suspend(dev);
147 else
148 return spi_legacy_suspend(dev, PMSG_SUSPEND);
149}
150
151static int spi_pm_resume(struct device *dev)
152{
153 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
154
155 if (pm)
156 return pm_generic_resume(dev);
157 else
158 return spi_legacy_resume(dev);
159}
160
161static int spi_pm_freeze(struct device *dev)
162{
163 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
164
165 if (pm)
166 return pm_generic_freeze(dev);
167 else
168 return spi_legacy_suspend(dev, PMSG_FREEZE);
169}
170
171static int spi_pm_thaw(struct device *dev)
172{
173 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
174
175 if (pm)
176 return pm_generic_thaw(dev);
177 else
178 return spi_legacy_resume(dev);
179}
180
181static int spi_pm_poweroff(struct device *dev)
182{
183 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
184
185 if (pm)
186 return pm_generic_poweroff(dev);
187 else
188 return spi_legacy_suspend(dev, PMSG_HIBERNATE);
189}
190
191static int spi_pm_restore(struct device *dev)
192{
193 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
194
195 if (pm)
196 return pm_generic_restore(dev);
197 else
198 return spi_legacy_resume(dev);
199}
David Brownell8ae12a02006-01-08 13:34:19 -0800200#else
Mark Brown3ae22e82010-12-25 15:32:27 +0100201#define spi_pm_suspend NULL
202#define spi_pm_resume NULL
203#define spi_pm_freeze NULL
204#define spi_pm_thaw NULL
205#define spi_pm_poweroff NULL
206#define spi_pm_restore NULL
David Brownell8ae12a02006-01-08 13:34:19 -0800207#endif
208
Mark Brown3ae22e82010-12-25 15:32:27 +0100209static const struct dev_pm_ops spi_pm = {
210 .suspend = spi_pm_suspend,
211 .resume = spi_pm_resume,
212 .freeze = spi_pm_freeze,
213 .thaw = spi_pm_thaw,
214 .poweroff = spi_pm_poweroff,
215 .restore = spi_pm_restore,
216 SET_RUNTIME_PM_OPS(
217 pm_generic_runtime_suspend,
218 pm_generic_runtime_resume,
219 pm_generic_runtime_idle
220 )
221};
222
David Brownell8ae12a02006-01-08 13:34:19 -0800223struct bus_type spi_bus_type = {
224 .name = "spi",
225 .dev_attrs = spi_dev_attrs,
226 .match = spi_match_device,
227 .uevent = spi_uevent,
Mark Brown3ae22e82010-12-25 15:32:27 +0100228 .pm = &spi_pm,
David Brownell8ae12a02006-01-08 13:34:19 -0800229};
230EXPORT_SYMBOL_GPL(spi_bus_type);
231
David Brownellb8852442006-01-08 13:34:23 -0800232
233static int spi_drv_probe(struct device *dev)
234{
235 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
236
237 return sdrv->probe(to_spi_device(dev));
238}
239
240static int spi_drv_remove(struct device *dev)
241{
242 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
243
244 return sdrv->remove(to_spi_device(dev));
245}
246
247static void spi_drv_shutdown(struct device *dev)
248{
249 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
250
251 sdrv->shutdown(to_spi_device(dev));
252}
253
David Brownell33e34dc2007-05-08 00:32:21 -0700254/**
255 * spi_register_driver - register a SPI driver
256 * @sdrv: the driver to register
257 * Context: can sleep
258 */
David Brownellb8852442006-01-08 13:34:23 -0800259int spi_register_driver(struct spi_driver *sdrv)
260{
261 sdrv->driver.bus = &spi_bus_type;
262 if (sdrv->probe)
263 sdrv->driver.probe = spi_drv_probe;
264 if (sdrv->remove)
265 sdrv->driver.remove = spi_drv_remove;
266 if (sdrv->shutdown)
267 sdrv->driver.shutdown = spi_drv_shutdown;
268 return driver_register(&sdrv->driver);
269}
270EXPORT_SYMBOL_GPL(spi_register_driver);
271
David Brownell8ae12a02006-01-08 13:34:19 -0800272/*-------------------------------------------------------------------------*/
273
274/* SPI devices should normally not be created by SPI device drivers; that
275 * would make them board-specific. Similarly with SPI master drivers.
276 * Device registration normally goes into like arch/.../mach.../board-YYY.c
277 * with other readonly (flashable) information about mainboard devices.
278 */
279
280struct boardinfo {
281 struct list_head list;
Feng Tang2b9603a2010-08-02 15:52:15 +0800282 struct spi_board_info board_info;
David Brownell8ae12a02006-01-08 13:34:19 -0800283};
284
285static LIST_HEAD(board_list);
Feng Tang2b9603a2010-08-02 15:52:15 +0800286static LIST_HEAD(spi_master_list);
287
288/*
289 * Used to protect add/del opertion for board_info list and
290 * spi_master list, and their matching process
291 */
Matthias Kaehlcke94040822007-07-17 04:04:16 -0700292static DEFINE_MUTEX(board_lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800293
Grant Likelydc87c982008-05-15 16:50:22 -0600294/**
295 * spi_alloc_device - Allocate a new SPI device
296 * @master: Controller to which device is connected
297 * Context: can sleep
298 *
299 * Allows a driver to allocate and initialize a spi_device without
300 * registering it immediately. This allows a driver to directly
301 * fill the spi_device with device parameters before calling
302 * spi_add_device() on it.
303 *
304 * Caller is responsible to call spi_add_device() on the returned
305 * spi_device structure to add it to the SPI master. If the caller
306 * needs to discard the spi_device without adding it, then it should
307 * call spi_dev_put() on it.
308 *
309 * Returns a pointer to the new device, or NULL.
310 */
311struct spi_device *spi_alloc_device(struct spi_master *master)
312{
313 struct spi_device *spi;
314 struct device *dev = master->dev.parent;
315
316 if (!spi_master_get(master))
317 return NULL;
318
319 spi = kzalloc(sizeof *spi, GFP_KERNEL);
320 if (!spi) {
321 dev_err(dev, "cannot alloc spi_device\n");
322 spi_master_put(master);
323 return NULL;
324 }
325
326 spi->master = master;
Laurent Pinchart178db7d2011-12-12 01:15:06 +0100327 spi->dev.parent = &master->dev;
Grant Likelydc87c982008-05-15 16:50:22 -0600328 spi->dev.bus = &spi_bus_type;
329 spi->dev.release = spidev_release;
330 device_initialize(&spi->dev);
331 return spi;
332}
333EXPORT_SYMBOL_GPL(spi_alloc_device);
334
335/**
336 * spi_add_device - Add spi_device allocated with spi_alloc_device
337 * @spi: spi_device to register
338 *
339 * Companion function to spi_alloc_device. Devices allocated with
340 * spi_alloc_device can be added onto the spi bus with this function.
341 *
David Brownelle48880e2008-08-15 00:40:44 -0700342 * Returns 0 on success; negative errno on failure
Grant Likelydc87c982008-05-15 16:50:22 -0600343 */
344int spi_add_device(struct spi_device *spi)
345{
David Brownelle48880e2008-08-15 00:40:44 -0700346 static DEFINE_MUTEX(spi_add_lock);
Grant Likelydc87c982008-05-15 16:50:22 -0600347 struct device *dev = spi->master->dev.parent;
Roman Tereshonkov8ec130a2010-04-16 09:52:59 +0000348 struct device *d;
Grant Likelydc87c982008-05-15 16:50:22 -0600349 int status;
350
351 /* Chipselects are numbered 0..max; validate. */
352 if (spi->chip_select >= spi->master->num_chipselect) {
353 dev_err(dev, "cs%d >= max %d\n",
354 spi->chip_select,
355 spi->master->num_chipselect);
356 return -EINVAL;
357 }
358
359 /* Set the bus ID string */
Kay Sievers35f74fc2009-01-06 10:44:37 -0800360 dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
Grant Likelydc87c982008-05-15 16:50:22 -0600361 spi->chip_select);
362
David Brownelle48880e2008-08-15 00:40:44 -0700363
364 /* We need to make sure there's no other device with this
365 * chipselect **BEFORE** we call setup(), else we'll trash
366 * its configuration. Lock against concurrent add() calls.
367 */
368 mutex_lock(&spi_add_lock);
369
Roman Tereshonkov8ec130a2010-04-16 09:52:59 +0000370 d = bus_find_device_by_name(&spi_bus_type, NULL, dev_name(&spi->dev));
371 if (d != NULL) {
David Brownelle48880e2008-08-15 00:40:44 -0700372 dev_err(dev, "chipselect %d already in use\n",
373 spi->chip_select);
Roman Tereshonkov8ec130a2010-04-16 09:52:59 +0000374 put_device(d);
David Brownelle48880e2008-08-15 00:40:44 -0700375 status = -EBUSY;
376 goto done;
377 }
378
379 /* Drivers may modify this initial i/o setup, but will
380 * normally rely on the device being setup. Devices
381 * using SPI_CS_HIGH can't coexist well otherwise...
382 */
David Brownell7d077192009-06-17 16:26:03 -0700383 status = spi_setup(spi);
Grant Likelydc87c982008-05-15 16:50:22 -0600384 if (status < 0) {
Linus Walleijeb288a12010-10-21 21:06:44 +0200385 dev_err(dev, "can't setup %s, status %d\n",
386 dev_name(&spi->dev), status);
David Brownelle48880e2008-08-15 00:40:44 -0700387 goto done;
Grant Likelydc87c982008-05-15 16:50:22 -0600388 }
389
David Brownelle48880e2008-08-15 00:40:44 -0700390 /* Device may be bound to an active driver when this returns */
Grant Likelydc87c982008-05-15 16:50:22 -0600391 status = device_add(&spi->dev);
David Brownelle48880e2008-08-15 00:40:44 -0700392 if (status < 0)
Linus Walleijeb288a12010-10-21 21:06:44 +0200393 dev_err(dev, "can't add %s, status %d\n",
394 dev_name(&spi->dev), status);
David Brownelle48880e2008-08-15 00:40:44 -0700395 else
Kay Sievers35f74fc2009-01-06 10:44:37 -0800396 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
Grant Likelydc87c982008-05-15 16:50:22 -0600397
David Brownelle48880e2008-08-15 00:40:44 -0700398done:
399 mutex_unlock(&spi_add_lock);
400 return status;
Grant Likelydc87c982008-05-15 16:50:22 -0600401}
402EXPORT_SYMBOL_GPL(spi_add_device);
David Brownell8ae12a02006-01-08 13:34:19 -0800403
David Brownell33e34dc2007-05-08 00:32:21 -0700404/**
405 * spi_new_device - instantiate one new SPI device
406 * @master: Controller to which device is connected
407 * @chip: Describes the SPI device
408 * Context: can sleep
409 *
410 * On typical mainboards, this is purely internal; and it's not needed
David Brownell8ae12a02006-01-08 13:34:19 -0800411 * after board init creates the hard-wired devices. Some development
412 * platforms may not be able to use spi_register_board_info though, and
413 * this is exported so that for example a USB or parport based adapter
414 * driver could add devices (which it would learn about out-of-band).
David Brownell082c8cb2007-07-31 00:39:45 -0700415 *
416 * Returns the new device, or NULL.
David Brownell8ae12a02006-01-08 13:34:19 -0800417 */
Adrian Bunke9d5a462007-03-26 21:32:23 -0800418struct spi_device *spi_new_device(struct spi_master *master,
419 struct spi_board_info *chip)
David Brownell8ae12a02006-01-08 13:34:19 -0800420{
421 struct spi_device *proxy;
David Brownell8ae12a02006-01-08 13:34:19 -0800422 int status;
423
David Brownell082c8cb2007-07-31 00:39:45 -0700424 /* NOTE: caller did any chip->bus_num checks necessary.
425 *
426 * Also, unless we change the return value convention to use
427 * error-or-pointer (not NULL-or-pointer), troubleshootability
428 * suggests syslogged diagnostics are best here (ugh).
429 */
430
Grant Likelydc87c982008-05-15 16:50:22 -0600431 proxy = spi_alloc_device(master);
432 if (!proxy)
David Brownell8ae12a02006-01-08 13:34:19 -0800433 return NULL;
434
Grant Likely102eb972008-07-23 21:29:55 -0700435 WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
436
David Brownell8ae12a02006-01-08 13:34:19 -0800437 proxy->chip_select = chip->chip_select;
438 proxy->max_speed_hz = chip->max_speed_hz;
David Brownell980a01c2006-06-28 07:47:15 -0700439 proxy->mode = chip->mode;
David Brownell8ae12a02006-01-08 13:34:19 -0800440 proxy->irq = chip->irq;
Grant Likely102eb972008-07-23 21:29:55 -0700441 strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
David Brownell8ae12a02006-01-08 13:34:19 -0800442 proxy->dev.platform_data = (void *) chip->platform_data;
443 proxy->controller_data = chip->controller_data;
444 proxy->controller_state = NULL;
David Brownell8ae12a02006-01-08 13:34:19 -0800445
Grant Likelydc87c982008-05-15 16:50:22 -0600446 status = spi_add_device(proxy);
David Brownell8ae12a02006-01-08 13:34:19 -0800447 if (status < 0) {
Grant Likelydc87c982008-05-15 16:50:22 -0600448 spi_dev_put(proxy);
449 return NULL;
David Brownell8ae12a02006-01-08 13:34:19 -0800450 }
451
David Brownell8ae12a02006-01-08 13:34:19 -0800452 return proxy;
453}
454EXPORT_SYMBOL_GPL(spi_new_device);
455
Feng Tang2b9603a2010-08-02 15:52:15 +0800456static void spi_match_master_to_boardinfo(struct spi_master *master,
457 struct spi_board_info *bi)
458{
459 struct spi_device *dev;
460
461 if (master->bus_num != bi->bus_num)
462 return;
463
464 dev = spi_new_device(master, bi);
465 if (!dev)
466 dev_err(master->dev.parent, "can't create new device for %s\n",
467 bi->modalias);
468}
469
David Brownell33e34dc2007-05-08 00:32:21 -0700470/**
471 * spi_register_board_info - register SPI devices for a given board
472 * @info: array of chip descriptors
473 * @n: how many descriptors are provided
474 * Context: can sleep
475 *
David Brownell8ae12a02006-01-08 13:34:19 -0800476 * Board-specific early init code calls this (probably during arch_initcall)
477 * with segments of the SPI device table. Any device nodes are created later,
478 * after the relevant parent SPI controller (bus_num) is defined. We keep
479 * this table of devices forever, so that reloading a controller driver will
480 * not make Linux forget about these hard-wired devices.
481 *
482 * Other code can also call this, e.g. a particular add-on board might provide
483 * SPI devices through its expansion connector, so code initializing that board
484 * would naturally declare its SPI devices.
485 *
486 * The board info passed can safely be __initdata ... but be careful of
487 * any embedded pointers (platform_data, etc), they're copied as-is.
488 */
Mark Brown690fb112012-02-17 16:23:29 -0800489int __devinit
David Brownell8ae12a02006-01-08 13:34:19 -0800490spi_register_board_info(struct spi_board_info const *info, unsigned n)
491{
Feng Tang2b9603a2010-08-02 15:52:15 +0800492 struct boardinfo *bi;
493 int i;
David Brownell8ae12a02006-01-08 13:34:19 -0800494
Feng Tang2b9603a2010-08-02 15:52:15 +0800495 bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
David Brownell8ae12a02006-01-08 13:34:19 -0800496 if (!bi)
497 return -ENOMEM;
David Brownell8ae12a02006-01-08 13:34:19 -0800498
Feng Tang2b9603a2010-08-02 15:52:15 +0800499 for (i = 0; i < n; i++, bi++, info++) {
500 struct spi_master *master;
David Brownell8ae12a02006-01-08 13:34:19 -0800501
Feng Tang2b9603a2010-08-02 15:52:15 +0800502 memcpy(&bi->board_info, info, sizeof(*info));
503 mutex_lock(&board_lock);
504 list_add_tail(&bi->list, &board_list);
505 list_for_each_entry(master, &spi_master_list, list)
506 spi_match_master_to_boardinfo(master, &bi->board_info);
507 mutex_unlock(&board_lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800508 }
Feng Tang2b9603a2010-08-02 15:52:15 +0800509
510 return 0;
David Brownell8ae12a02006-01-08 13:34:19 -0800511}
512
513/*-------------------------------------------------------------------------*/
514
Linus Walleijffbbdd212012-02-22 10:05:38 +0100515/**
516 * spi_pump_messages - kthread work function which processes spi message queue
517 * @work: pointer to kthread work struct contained in the master struct
518 *
519 * This function checks if there is any spi message in the queue that
520 * needs processing and if so call out to the driver to initialize hardware
521 * and transfer each message.
522 *
523 */
524static void spi_pump_messages(struct kthread_work *work)
525{
526 struct spi_master *master =
527 container_of(work, struct spi_master, pump_messages);
528 unsigned long flags;
529 bool was_busy = false;
530 int ret;
531
532 /* Lock queue and check for queue work */
533 spin_lock_irqsave(&master->queue_lock, flags);
534 if (list_empty(&master->queue) || !master->running) {
Shubhrajyoti D7dfd2bd2012-05-10 19:20:41 +0530535 if (master->busy && master->unprepare_transfer_hardware) {
Linus Walleijffbbdd212012-02-22 10:05:38 +0100536 ret = master->unprepare_transfer_hardware(master);
537 if (ret) {
Dan Carpenter9af4acc2012-03-10 11:57:29 +0300538 spin_unlock_irqrestore(&master->queue_lock, flags);
Linus Walleijffbbdd212012-02-22 10:05:38 +0100539 dev_err(&master->dev,
540 "failed to unprepare transfer hardware\n");
541 return;
542 }
543 }
544 master->busy = false;
545 spin_unlock_irqrestore(&master->queue_lock, flags);
546 return;
547 }
548
549 /* Make sure we are not already running a message */
550 if (master->cur_msg) {
551 spin_unlock_irqrestore(&master->queue_lock, flags);
552 return;
553 }
554 /* Extract head of queue */
555 master->cur_msg =
556 list_entry(master->queue.next, struct spi_message, queue);
557
558 list_del_init(&master->cur_msg->queue);
559 if (master->busy)
560 was_busy = true;
561 else
562 master->busy = true;
563 spin_unlock_irqrestore(&master->queue_lock, flags);
564
Shubhrajyoti D7dfd2bd2012-05-10 19:20:41 +0530565 if (!was_busy && master->prepare_transfer_hardware) {
Linus Walleijffbbdd212012-02-22 10:05:38 +0100566 ret = master->prepare_transfer_hardware(master);
567 if (ret) {
568 dev_err(&master->dev,
569 "failed to prepare transfer hardware\n");
570 return;
571 }
572 }
573
574 ret = master->transfer_one_message(master, master->cur_msg);
575 if (ret) {
576 dev_err(&master->dev,
577 "failed to transfer one message from queue\n");
578 return;
579 }
580}
581
582static int spi_init_queue(struct spi_master *master)
583{
584 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
585
586 INIT_LIST_HEAD(&master->queue);
587 spin_lock_init(&master->queue_lock);
588
589 master->running = false;
590 master->busy = false;
591
592 init_kthread_worker(&master->kworker);
593 master->kworker_task = kthread_run(kthread_worker_fn,
594 &master->kworker,
595 dev_name(&master->dev));
596 if (IS_ERR(master->kworker_task)) {
597 dev_err(&master->dev, "failed to create message pump task\n");
598 return -ENOMEM;
599 }
600 init_kthread_work(&master->pump_messages, spi_pump_messages);
601
602 /*
603 * Master config will indicate if this controller should run the
604 * message pump with high (realtime) priority to reduce the transfer
605 * latency on the bus by minimising the delay between a transfer
606 * request and the scheduling of the message pump thread. Without this
607 * setting the message pump thread will remain at default priority.
608 */
609 if (master->rt) {
610 dev_info(&master->dev,
611 "will run message pump with realtime priority\n");
612 sched_setscheduler(master->kworker_task, SCHED_FIFO, &param);
613 }
614
615 return 0;
616}
617
618/**
619 * spi_get_next_queued_message() - called by driver to check for queued
620 * messages
621 * @master: the master to check for queued messages
622 *
623 * If there are more messages in the queue, the next message is returned from
624 * this call.
625 */
626struct spi_message *spi_get_next_queued_message(struct spi_master *master)
627{
628 struct spi_message *next;
629 unsigned long flags;
630
631 /* get a pointer to the next message, if any */
632 spin_lock_irqsave(&master->queue_lock, flags);
633 if (list_empty(&master->queue))
634 next = NULL;
635 else
636 next = list_entry(master->queue.next,
637 struct spi_message, queue);
638 spin_unlock_irqrestore(&master->queue_lock, flags);
639
640 return next;
641}
642EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
643
644/**
645 * spi_finalize_current_message() - the current message is complete
646 * @master: the master to return the message to
647 *
648 * Called by the driver to notify the core that the message in the front of the
649 * queue is complete and can be removed from the queue.
650 */
651void spi_finalize_current_message(struct spi_master *master)
652{
653 struct spi_message *mesg;
654 unsigned long flags;
655
656 spin_lock_irqsave(&master->queue_lock, flags);
657 mesg = master->cur_msg;
658 master->cur_msg = NULL;
659
660 queue_kthread_work(&master->kworker, &master->pump_messages);
661 spin_unlock_irqrestore(&master->queue_lock, flags);
662
663 mesg->state = NULL;
664 if (mesg->complete)
665 mesg->complete(mesg->context);
666}
667EXPORT_SYMBOL_GPL(spi_finalize_current_message);
668
669static int spi_start_queue(struct spi_master *master)
670{
671 unsigned long flags;
672
673 spin_lock_irqsave(&master->queue_lock, flags);
674
675 if (master->running || master->busy) {
676 spin_unlock_irqrestore(&master->queue_lock, flags);
677 return -EBUSY;
678 }
679
680 master->running = true;
681 master->cur_msg = NULL;
682 spin_unlock_irqrestore(&master->queue_lock, flags);
683
684 queue_kthread_work(&master->kworker, &master->pump_messages);
685
686 return 0;
687}
688
689static int spi_stop_queue(struct spi_master *master)
690{
691 unsigned long flags;
692 unsigned limit = 500;
693 int ret = 0;
694
695 spin_lock_irqsave(&master->queue_lock, flags);
696
697 /*
698 * This is a bit lame, but is optimized for the common execution path.
699 * A wait_queue on the master->busy could be used, but then the common
700 * execution path (pump_messages) would be required to call wake_up or
701 * friends on every SPI message. Do this instead.
702 */
703 while ((!list_empty(&master->queue) || master->busy) && limit--) {
704 spin_unlock_irqrestore(&master->queue_lock, flags);
705 msleep(10);
706 spin_lock_irqsave(&master->queue_lock, flags);
707 }
708
709 if (!list_empty(&master->queue) || master->busy)
710 ret = -EBUSY;
711 else
712 master->running = false;
713
714 spin_unlock_irqrestore(&master->queue_lock, flags);
715
716 if (ret) {
717 dev_warn(&master->dev,
718 "could not stop message queue\n");
719 return ret;
720 }
721 return ret;
722}
723
724static int spi_destroy_queue(struct spi_master *master)
725{
726 int ret;
727
728 ret = spi_stop_queue(master);
729
730 /*
731 * flush_kthread_worker will block until all work is done.
732 * If the reason that stop_queue timed out is that the work will never
733 * finish, then it does no good to call flush/stop thread, so
734 * return anyway.
735 */
736 if (ret) {
737 dev_err(&master->dev, "problem destroying queue\n");
738 return ret;
739 }
740
741 flush_kthread_worker(&master->kworker);
742 kthread_stop(master->kworker_task);
743
744 return 0;
745}
746
747/**
748 * spi_queued_transfer - transfer function for queued transfers
749 * @spi: spi device which is requesting transfer
750 * @msg: spi message which is to handled is queued to driver queue
751 */
752static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
753{
754 struct spi_master *master = spi->master;
755 unsigned long flags;
756
757 spin_lock_irqsave(&master->queue_lock, flags);
758
759 if (!master->running) {
760 spin_unlock_irqrestore(&master->queue_lock, flags);
761 return -ESHUTDOWN;
762 }
763 msg->actual_length = 0;
764 msg->status = -EINPROGRESS;
765
766 list_add_tail(&msg->queue, &master->queue);
767 if (master->running && !master->busy)
768 queue_kthread_work(&master->kworker, &master->pump_messages);
769
770 spin_unlock_irqrestore(&master->queue_lock, flags);
771 return 0;
772}
773
774static int spi_master_initialize_queue(struct spi_master *master)
775{
776 int ret;
777
778 master->queued = true;
779 master->transfer = spi_queued_transfer;
780
781 /* Initialize and start queue */
782 ret = spi_init_queue(master);
783 if (ret) {
784 dev_err(&master->dev, "problem initializing queue\n");
785 goto err_init_queue;
786 }
787 ret = spi_start_queue(master);
788 if (ret) {
789 dev_err(&master->dev, "problem starting queue\n");
790 goto err_start_queue;
791 }
792
793 return 0;
794
795err_start_queue:
796err_init_queue:
797 spi_destroy_queue(master);
798 return ret;
799}
800
801/*-------------------------------------------------------------------------*/
802
Grant Likelyd57a4282012-04-07 14:16:53 -0600803#if defined(CONFIG_OF) && !defined(CONFIG_SPARC)
804/**
805 * of_register_spi_devices() - Register child devices onto the SPI bus
806 * @master: Pointer to spi_master device
807 *
808 * Registers an spi_device for each child node of master node which has a 'reg'
809 * property.
810 */
811static void of_register_spi_devices(struct spi_master *master)
812{
813 struct spi_device *spi;
814 struct device_node *nc;
815 const __be32 *prop;
816 int rc;
817 int len;
818
819 if (!master->dev.of_node)
820 return;
821
822 for_each_child_of_node(master->dev.of_node, nc) {
823 /* Alloc an spi_device */
824 spi = spi_alloc_device(master);
825 if (!spi) {
826 dev_err(&master->dev, "spi_device alloc error for %s\n",
827 nc->full_name);
828 spi_dev_put(spi);
829 continue;
830 }
831
832 /* Select device driver */
833 if (of_modalias_node(nc, spi->modalias,
834 sizeof(spi->modalias)) < 0) {
835 dev_err(&master->dev, "cannot find modalias for %s\n",
836 nc->full_name);
837 spi_dev_put(spi);
838 continue;
839 }
840
841 /* Device address */
842 prop = of_get_property(nc, "reg", &len);
843 if (!prop || len < sizeof(*prop)) {
844 dev_err(&master->dev, "%s has no 'reg' property\n",
845 nc->full_name);
846 spi_dev_put(spi);
847 continue;
848 }
849 spi->chip_select = be32_to_cpup(prop);
850
851 /* Mode (clock phase/polarity/etc.) */
852 if (of_find_property(nc, "spi-cpha", NULL))
853 spi->mode |= SPI_CPHA;
854 if (of_find_property(nc, "spi-cpol", NULL))
855 spi->mode |= SPI_CPOL;
856 if (of_find_property(nc, "spi-cs-high", NULL))
857 spi->mode |= SPI_CS_HIGH;
858
859 /* Device speed */
860 prop = of_get_property(nc, "spi-max-frequency", &len);
861 if (!prop || len < sizeof(*prop)) {
862 dev_err(&master->dev, "%s has no 'spi-max-frequency' property\n",
863 nc->full_name);
864 spi_dev_put(spi);
865 continue;
866 }
867 spi->max_speed_hz = be32_to_cpup(prop);
868
869 /* IRQ */
870 spi->irq = irq_of_parse_and_map(nc, 0);
871
872 /* Store a pointer to the node in the device structure */
873 of_node_get(nc);
874 spi->dev.of_node = nc;
875
876 /* Register the new device */
877 request_module(spi->modalias);
878 rc = spi_add_device(spi);
879 if (rc) {
880 dev_err(&master->dev, "spi_device register error %s\n",
881 nc->full_name);
882 spi_dev_put(spi);
883 }
884
885 }
886}
887#else
888static void of_register_spi_devices(struct spi_master *master) { }
889#endif
890
Tony Jones49dce682007-10-16 01:27:48 -0700891static void spi_master_release(struct device *dev)
David Brownell8ae12a02006-01-08 13:34:19 -0800892{
893 struct spi_master *master;
894
Tony Jones49dce682007-10-16 01:27:48 -0700895 master = container_of(dev, struct spi_master, dev);
David Brownell8ae12a02006-01-08 13:34:19 -0800896 kfree(master);
897}
898
899static struct class spi_master_class = {
900 .name = "spi_master",
901 .owner = THIS_MODULE,
Tony Jones49dce682007-10-16 01:27:48 -0700902 .dev_release = spi_master_release,
David Brownell8ae12a02006-01-08 13:34:19 -0800903};
904
905
Linus Walleijffbbdd212012-02-22 10:05:38 +0100906
David Brownell8ae12a02006-01-08 13:34:19 -0800907/**
908 * spi_alloc_master - allocate SPI master controller
909 * @dev: the controller, possibly using the platform_bus
David Brownell33e34dc2007-05-08 00:32:21 -0700910 * @size: how much zeroed driver-private data to allocate; the pointer to this
Tony Jones49dce682007-10-16 01:27:48 -0700911 * memory is in the driver_data field of the returned device,
David Brownell0c868462006-01-08 13:34:25 -0800912 * accessible with spi_master_get_devdata().
David Brownell33e34dc2007-05-08 00:32:21 -0700913 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800914 *
915 * This call is used only by SPI master controller drivers, which are the
916 * only ones directly touching chip registers. It's how they allocate
dmitry pervushinba1a0512006-05-20 15:00:14 -0700917 * an spi_master structure, prior to calling spi_register_master().
David Brownell8ae12a02006-01-08 13:34:19 -0800918 *
919 * This must be called from context that can sleep. It returns the SPI
920 * master structure on success, else NULL.
921 *
922 * The caller is responsible for assigning the bus number and initializing
dmitry pervushinba1a0512006-05-20 15:00:14 -0700923 * the master's methods before calling spi_register_master(); and (after errors
Uwe Kleine-Königeb4af0f2012-02-23 10:40:14 +0100924 * adding the device) calling spi_master_put() and kfree() to prevent a memory
925 * leak.
David Brownell8ae12a02006-01-08 13:34:19 -0800926 */
Adrian Bunke9d5a462007-03-26 21:32:23 -0800927struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
David Brownell8ae12a02006-01-08 13:34:19 -0800928{
929 struct spi_master *master;
930
David Brownell0c868462006-01-08 13:34:25 -0800931 if (!dev)
932 return NULL;
933
Christoph Lametere94b1762006-12-06 20:33:17 -0800934 master = kzalloc(size + sizeof *master, GFP_KERNEL);
David Brownell8ae12a02006-01-08 13:34:19 -0800935 if (!master)
936 return NULL;
937
Tony Jones49dce682007-10-16 01:27:48 -0700938 device_initialize(&master->dev);
Grant Likely1e8a52e2012-05-19 23:42:08 -0600939 master->bus_num = -1;
940 master->num_chipselect = 1;
Tony Jones49dce682007-10-16 01:27:48 -0700941 master->dev.class = &spi_master_class;
942 master->dev.parent = get_device(dev);
David Brownell0c868462006-01-08 13:34:25 -0800943 spi_master_set_devdata(master, &master[1]);
David Brownell8ae12a02006-01-08 13:34:19 -0800944
945 return master;
946}
947EXPORT_SYMBOL_GPL(spi_alloc_master);
948
949/**
950 * spi_register_master - register SPI master controller
951 * @master: initialized master, originally from spi_alloc_master()
David Brownell33e34dc2007-05-08 00:32:21 -0700952 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800953 *
954 * SPI master controllers connect to their drivers using some non-SPI bus,
955 * such as the platform bus. The final stage of probe() in that code
956 * includes calling spi_register_master() to hook up to this SPI bus glue.
957 *
958 * SPI controllers use board specific (often SOC specific) bus numbers,
959 * and board-specific addressing for SPI devices combines those numbers
960 * with chip select numbers. Since SPI does not directly support dynamic
961 * device identification, boards need configuration tables telling which
962 * chip is at which address.
963 *
964 * This must be called from context that can sleep. It returns zero on
965 * success, else a negative error code (dropping the master's refcount).
David Brownell0c868462006-01-08 13:34:25 -0800966 * After a successful return, the caller is responsible for calling
967 * spi_unregister_master().
David Brownell8ae12a02006-01-08 13:34:19 -0800968 */
Adrian Bunke9d5a462007-03-26 21:32:23 -0800969int spi_register_master(struct spi_master *master)
David Brownell8ae12a02006-01-08 13:34:19 -0800970{
David Brownelle44a45a2007-06-03 13:50:40 -0700971 static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
Tony Jones49dce682007-10-16 01:27:48 -0700972 struct device *dev = master->dev.parent;
Feng Tang2b9603a2010-08-02 15:52:15 +0800973 struct boardinfo *bi;
David Brownell8ae12a02006-01-08 13:34:19 -0800974 int status = -ENODEV;
975 int dynamic = 0;
976
David Brownell0c868462006-01-08 13:34:25 -0800977 if (!dev)
978 return -ENODEV;
979
David Brownell082c8cb2007-07-31 00:39:45 -0700980 /* even if it's just one always-selected device, there must
981 * be at least one chipselect
982 */
983 if (master->num_chipselect == 0)
984 return -EINVAL;
985
David Brownell8ae12a02006-01-08 13:34:19 -0800986 /* convention: dynamically assigned bus IDs count down from the max */
David Brownella020ed72006-04-03 15:49:04 -0700987 if (master->bus_num < 0) {
David Brownell082c8cb2007-07-31 00:39:45 -0700988 /* FIXME switch to an IDR based scheme, something like
989 * I2C now uses, so we can't run out of "dynamic" IDs
990 */
David Brownell8ae12a02006-01-08 13:34:19 -0800991 master->bus_num = atomic_dec_return(&dyn_bus_id);
David Brownellb8852442006-01-08 13:34:23 -0800992 dynamic = 1;
David Brownell8ae12a02006-01-08 13:34:19 -0800993 }
994
Ernst Schwabcf32b712010-06-28 17:49:29 -0700995 spin_lock_init(&master->bus_lock_spinlock);
996 mutex_init(&master->bus_lock_mutex);
997 master->bus_lock_flag = 0;
998
David Brownell8ae12a02006-01-08 13:34:19 -0800999 /* register the device, then userspace will see it.
1000 * registration fails if the bus ID is in use.
1001 */
Kay Sievers35f74fc2009-01-06 10:44:37 -08001002 dev_set_name(&master->dev, "spi%u", master->bus_num);
Tony Jones49dce682007-10-16 01:27:48 -07001003 status = device_add(&master->dev);
David Brownellb8852442006-01-08 13:34:23 -08001004 if (status < 0)
David Brownell8ae12a02006-01-08 13:34:19 -08001005 goto done;
Kay Sievers35f74fc2009-01-06 10:44:37 -08001006 dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
David Brownell8ae12a02006-01-08 13:34:19 -08001007 dynamic ? " (dynamic)" : "");
1008
Linus Walleijffbbdd212012-02-22 10:05:38 +01001009 /* If we're using a queued driver, start the queue */
1010 if (master->transfer)
1011 dev_info(dev, "master is unqueued, this is deprecated\n");
1012 else {
1013 status = spi_master_initialize_queue(master);
1014 if (status) {
1015 device_unregister(&master->dev);
1016 goto done;
1017 }
1018 }
1019
Feng Tang2b9603a2010-08-02 15:52:15 +08001020 mutex_lock(&board_lock);
1021 list_add_tail(&master->list, &spi_master_list);
1022 list_for_each_entry(bi, &board_list, list)
1023 spi_match_master_to_boardinfo(master, &bi->board_info);
1024 mutex_unlock(&board_lock);
1025
Anatolij Gustschin12b15e82010-07-27 22:35:58 +02001026 /* Register devices from the device tree */
1027 of_register_spi_devices(master);
David Brownell8ae12a02006-01-08 13:34:19 -08001028done:
1029 return status;
1030}
1031EXPORT_SYMBOL_GPL(spi_register_master);
1032
David Lamparter34860082010-08-30 23:54:17 +02001033static int __unregister(struct device *dev, void *null)
David Brownell8ae12a02006-01-08 13:34:19 -08001034{
David Lamparter34860082010-08-30 23:54:17 +02001035 spi_unregister_device(to_spi_device(dev));
David Brownell8ae12a02006-01-08 13:34:19 -08001036 return 0;
1037}
1038
1039/**
1040 * spi_unregister_master - unregister SPI master controller
1041 * @master: the master being unregistered
David Brownell33e34dc2007-05-08 00:32:21 -07001042 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -08001043 *
1044 * This call is used only by SPI master controller drivers, which are the
1045 * only ones directly touching chip registers.
1046 *
1047 * This must be called from context that can sleep.
1048 */
1049void spi_unregister_master(struct spi_master *master)
1050{
Jeff Garzik89fc9a12006-12-06 20:35:35 -08001051 int dummy;
1052
Linus Walleijffbbdd212012-02-22 10:05:38 +01001053 if (master->queued) {
1054 if (spi_destroy_queue(master))
1055 dev_err(&master->dev, "queue remove failed\n");
1056 }
1057
Feng Tang2b9603a2010-08-02 15:52:15 +08001058 mutex_lock(&board_lock);
1059 list_del(&master->list);
1060 mutex_unlock(&board_lock);
1061
Sebastian Andrzej Siewior97dbf372010-12-21 17:24:31 -08001062 dummy = device_for_each_child(&master->dev, NULL, __unregister);
Tony Jones49dce682007-10-16 01:27:48 -07001063 device_unregister(&master->dev);
David Brownell8ae12a02006-01-08 13:34:19 -08001064}
1065EXPORT_SYMBOL_GPL(spi_unregister_master);
1066
Linus Walleijffbbdd212012-02-22 10:05:38 +01001067int spi_master_suspend(struct spi_master *master)
1068{
1069 int ret;
1070
1071 /* Basically no-ops for non-queued masters */
1072 if (!master->queued)
1073 return 0;
1074
1075 ret = spi_stop_queue(master);
1076 if (ret)
1077 dev_err(&master->dev, "queue stop failed\n");
1078
1079 return ret;
1080}
1081EXPORT_SYMBOL_GPL(spi_master_suspend);
1082
1083int spi_master_resume(struct spi_master *master)
1084{
1085 int ret;
1086
1087 if (!master->queued)
1088 return 0;
1089
1090 ret = spi_start_queue(master);
1091 if (ret)
1092 dev_err(&master->dev, "queue restart failed\n");
1093
1094 return ret;
1095}
1096EXPORT_SYMBOL_GPL(spi_master_resume);
1097
Dave Young5ed2c832008-01-22 15:14:18 +08001098static int __spi_master_match(struct device *dev, void *data)
1099{
1100 struct spi_master *m;
1101 u16 *bus_num = data;
1102
1103 m = container_of(dev, struct spi_master, dev);
1104 return m->bus_num == *bus_num;
1105}
1106
David Brownell8ae12a02006-01-08 13:34:19 -08001107/**
1108 * spi_busnum_to_master - look up master associated with bus_num
1109 * @bus_num: the master's bus number
David Brownell33e34dc2007-05-08 00:32:21 -07001110 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -08001111 *
1112 * This call may be used with devices that are registered after
1113 * arch init time. It returns a refcounted pointer to the relevant
1114 * spi_master (which the caller must release), or NULL if there is
1115 * no such master registered.
1116 */
1117struct spi_master *spi_busnum_to_master(u16 bus_num)
1118{
Tony Jones49dce682007-10-16 01:27:48 -07001119 struct device *dev;
Atsushi Nemoto1e9a51d2007-01-26 00:56:54 -08001120 struct spi_master *master = NULL;
David Brownell8ae12a02006-01-08 13:34:19 -08001121
Greg Kroah-Hartman695794a2008-05-22 17:21:08 -04001122 dev = class_find_device(&spi_master_class, NULL, &bus_num,
Dave Young5ed2c832008-01-22 15:14:18 +08001123 __spi_master_match);
1124 if (dev)
1125 master = container_of(dev, struct spi_master, dev);
1126 /* reference got in class_find_device */
Atsushi Nemoto1e9a51d2007-01-26 00:56:54 -08001127 return master;
David Brownell8ae12a02006-01-08 13:34:19 -08001128}
1129EXPORT_SYMBOL_GPL(spi_busnum_to_master);
1130
1131
1132/*-------------------------------------------------------------------------*/
1133
David Brownell7d077192009-06-17 16:26:03 -07001134/* Core methods for SPI master protocol drivers. Some of the
1135 * other core methods are currently defined as inline functions.
1136 */
1137
1138/**
1139 * spi_setup - setup SPI mode and clock rate
1140 * @spi: the device whose settings are being modified
1141 * Context: can sleep, and no requests are queued to the device
1142 *
1143 * SPI protocol drivers may need to update the transfer mode if the
1144 * device doesn't work with its default. They may likewise need
1145 * to update clock rates or word sizes from initial values. This function
1146 * changes those settings, and must be called from a context that can sleep.
1147 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
1148 * effect the next time the device is selected and data is transferred to
1149 * or from it. When this function returns, the spi device is deselected.
1150 *
1151 * Note that this call will fail if the protocol driver specifies an option
1152 * that the underlying controller or its driver does not support. For
1153 * example, not all hardware supports wire transfers using nine bit words,
1154 * LSB-first wire encoding, or active-high chipselects.
1155 */
1156int spi_setup(struct spi_device *spi)
1157{
David Brownelle7db06b2009-06-17 16:26:04 -07001158 unsigned bad_bits;
David Brownell7d077192009-06-17 16:26:03 -07001159 int status;
1160
David Brownelle7db06b2009-06-17 16:26:04 -07001161 /* help drivers fail *cleanly* when they need options
1162 * that aren't supported with their current master
1163 */
1164 bad_bits = spi->mode & ~spi->master->mode_bits;
1165 if (bad_bits) {
Linus Walleijeb288a12010-10-21 21:06:44 +02001166 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
David Brownelle7db06b2009-06-17 16:26:04 -07001167 bad_bits);
1168 return -EINVAL;
1169 }
1170
David Brownell7d077192009-06-17 16:26:03 -07001171 if (!spi->bits_per_word)
1172 spi->bits_per_word = 8;
1173
1174 status = spi->master->setup(spi);
1175
1176 dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s"
1177 "%u bits/w, %u Hz max --> %d\n",
1178 (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
1179 (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
1180 (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
1181 (spi->mode & SPI_3WIRE) ? "3wire, " : "",
1182 (spi->mode & SPI_LOOP) ? "loopback, " : "",
1183 spi->bits_per_word, spi->max_speed_hz,
1184 status);
1185
1186 return status;
1187}
1188EXPORT_SYMBOL_GPL(spi_setup);
1189
Ernst Schwabcf32b712010-06-28 17:49:29 -07001190static int __spi_async(struct spi_device *spi, struct spi_message *message)
1191{
1192 struct spi_master *master = spi->master;
1193
1194 /* Half-duplex links include original MicroWire, and ones with
1195 * only one data pin like SPI_3WIRE (switches direction) or where
1196 * either MOSI or MISO is missing. They can also be caused by
1197 * software limitations.
1198 */
1199 if ((master->flags & SPI_MASTER_HALF_DUPLEX)
1200 || (spi->mode & SPI_3WIRE)) {
1201 struct spi_transfer *xfer;
1202 unsigned flags = master->flags;
1203
1204 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1205 if (xfer->rx_buf && xfer->tx_buf)
1206 return -EINVAL;
1207 if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
1208 return -EINVAL;
1209 if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
1210 return -EINVAL;
1211 }
1212 }
1213
1214 message->spi = spi;
1215 message->status = -EINPROGRESS;
1216 return master->transfer(spi, message);
1217}
1218
David Brownell568d0692009-09-22 16:46:18 -07001219/**
1220 * spi_async - asynchronous SPI transfer
1221 * @spi: device with which data will be exchanged
1222 * @message: describes the data transfers, including completion callback
1223 * Context: any (irqs may be blocked, etc)
1224 *
1225 * This call may be used in_irq and other contexts which can't sleep,
1226 * as well as from task contexts which can sleep.
1227 *
1228 * The completion callback is invoked in a context which can't sleep.
1229 * Before that invocation, the value of message->status is undefined.
1230 * When the callback is issued, message->status holds either zero (to
1231 * indicate complete success) or a negative error code. After that
1232 * callback returns, the driver which issued the transfer request may
1233 * deallocate the associated memory; it's no longer in use by any SPI
1234 * core or controller driver code.
1235 *
1236 * Note that although all messages to a spi_device are handled in
1237 * FIFO order, messages may go to different devices in other orders.
1238 * Some device might be higher priority, or have various "hard" access
1239 * time requirements, for example.
1240 *
1241 * On detection of any fault during the transfer, processing of
1242 * the entire message is aborted, and the device is deselected.
1243 * Until returning from the associated message completion callback,
1244 * no other spi_message queued to that device will be processed.
1245 * (This rule applies equally to all the synchronous transfer calls,
1246 * which are wrappers around this core asynchronous primitive.)
1247 */
1248int spi_async(struct spi_device *spi, struct spi_message *message)
1249{
1250 struct spi_master *master = spi->master;
Ernst Schwabcf32b712010-06-28 17:49:29 -07001251 int ret;
1252 unsigned long flags;
David Brownell568d0692009-09-22 16:46:18 -07001253
Ernst Schwabcf32b712010-06-28 17:49:29 -07001254 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
David Brownell568d0692009-09-22 16:46:18 -07001255
Ernst Schwabcf32b712010-06-28 17:49:29 -07001256 if (master->bus_lock_flag)
1257 ret = -EBUSY;
1258 else
1259 ret = __spi_async(spi, message);
David Brownell568d0692009-09-22 16:46:18 -07001260
Ernst Schwabcf32b712010-06-28 17:49:29 -07001261 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
1262
1263 return ret;
David Brownell568d0692009-09-22 16:46:18 -07001264}
1265EXPORT_SYMBOL_GPL(spi_async);
1266
Ernst Schwabcf32b712010-06-28 17:49:29 -07001267/**
1268 * spi_async_locked - version of spi_async with exclusive bus usage
1269 * @spi: device with which data will be exchanged
1270 * @message: describes the data transfers, including completion callback
1271 * Context: any (irqs may be blocked, etc)
1272 *
1273 * This call may be used in_irq and other contexts which can't sleep,
1274 * as well as from task contexts which can sleep.
1275 *
1276 * The completion callback is invoked in a context which can't sleep.
1277 * Before that invocation, the value of message->status is undefined.
1278 * When the callback is issued, message->status holds either zero (to
1279 * indicate complete success) or a negative error code. After that
1280 * callback returns, the driver which issued the transfer request may
1281 * deallocate the associated memory; it's no longer in use by any SPI
1282 * core or controller driver code.
1283 *
1284 * Note that although all messages to a spi_device are handled in
1285 * FIFO order, messages may go to different devices in other orders.
1286 * Some device might be higher priority, or have various "hard" access
1287 * time requirements, for example.
1288 *
1289 * On detection of any fault during the transfer, processing of
1290 * the entire message is aborted, and the device is deselected.
1291 * Until returning from the associated message completion callback,
1292 * no other spi_message queued to that device will be processed.
1293 * (This rule applies equally to all the synchronous transfer calls,
1294 * which are wrappers around this core asynchronous primitive.)
1295 */
1296int spi_async_locked(struct spi_device *spi, struct spi_message *message)
1297{
1298 struct spi_master *master = spi->master;
1299 int ret;
1300 unsigned long flags;
1301
1302 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
1303
1304 ret = __spi_async(spi, message);
1305
1306 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
1307
1308 return ret;
1309
1310}
1311EXPORT_SYMBOL_GPL(spi_async_locked);
1312
David Brownell7d077192009-06-17 16:26:03 -07001313
1314/*-------------------------------------------------------------------------*/
1315
1316/* Utility methods for SPI master protocol drivers, layered on
1317 * top of the core. Some other utility methods are defined as
1318 * inline functions.
1319 */
1320
Andrew Morton5d870c82006-01-11 11:23:49 -08001321static void spi_complete(void *arg)
1322{
1323 complete(arg);
1324}
1325
Ernst Schwabcf32b712010-06-28 17:49:29 -07001326static int __spi_sync(struct spi_device *spi, struct spi_message *message,
1327 int bus_locked)
1328{
1329 DECLARE_COMPLETION_ONSTACK(done);
1330 int status;
1331 struct spi_master *master = spi->master;
1332
1333 message->complete = spi_complete;
1334 message->context = &done;
1335
1336 if (!bus_locked)
1337 mutex_lock(&master->bus_lock_mutex);
1338
1339 status = spi_async_locked(spi, message);
1340
1341 if (!bus_locked)
1342 mutex_unlock(&master->bus_lock_mutex);
1343
1344 if (status == 0) {
1345 wait_for_completion(&done);
1346 status = message->status;
1347 }
1348 message->context = NULL;
1349 return status;
1350}
1351
David Brownell8ae12a02006-01-08 13:34:19 -08001352/**
1353 * spi_sync - blocking/synchronous SPI data transfers
1354 * @spi: device with which data will be exchanged
1355 * @message: describes the data transfers
David Brownell33e34dc2007-05-08 00:32:21 -07001356 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -08001357 *
1358 * This call may only be used from a context that may sleep. The sleep
1359 * is non-interruptible, and has no timeout. Low-overhead controller
1360 * drivers may DMA directly into and out of the message buffers.
1361 *
1362 * Note that the SPI device's chip select is active during the message,
1363 * and then is normally disabled between messages. Drivers for some
1364 * frequently-used devices may want to minimize costs of selecting a chip,
1365 * by leaving it selected in anticipation that the next message will go
1366 * to the same chip. (That may increase power usage.)
1367 *
David Brownell0c868462006-01-08 13:34:25 -08001368 * Also, the caller is guaranteeing that the memory associated with the
1369 * message will not be freed before this call returns.
1370 *
Marc Pignat9b938b72007-12-04 23:45:10 -08001371 * It returns zero on success, else a negative error code.
David Brownell8ae12a02006-01-08 13:34:19 -08001372 */
1373int spi_sync(struct spi_device *spi, struct spi_message *message)
1374{
Ernst Schwabcf32b712010-06-28 17:49:29 -07001375 return __spi_sync(spi, message, 0);
David Brownell8ae12a02006-01-08 13:34:19 -08001376}
1377EXPORT_SYMBOL_GPL(spi_sync);
1378
Ernst Schwabcf32b712010-06-28 17:49:29 -07001379/**
1380 * spi_sync_locked - version of spi_sync with exclusive bus usage
1381 * @spi: device with which data will be exchanged
1382 * @message: describes the data transfers
1383 * Context: can sleep
1384 *
1385 * This call may only be used from a context that may sleep. The sleep
1386 * is non-interruptible, and has no timeout. Low-overhead controller
1387 * drivers may DMA directly into and out of the message buffers.
1388 *
1389 * This call should be used by drivers that require exclusive access to the
Lucas De Marchi25985ed2011-03-30 22:57:33 -03001390 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
Ernst Schwabcf32b712010-06-28 17:49:29 -07001391 * be released by a spi_bus_unlock call when the exclusive access is over.
1392 *
1393 * It returns zero on success, else a negative error code.
1394 */
1395int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
1396{
1397 return __spi_sync(spi, message, 1);
1398}
1399EXPORT_SYMBOL_GPL(spi_sync_locked);
1400
1401/**
1402 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
1403 * @master: SPI bus master that should be locked for exclusive bus access
1404 * Context: can sleep
1405 *
1406 * This call may only be used from a context that may sleep. The sleep
1407 * is non-interruptible, and has no timeout.
1408 *
1409 * This call should be used by drivers that require exclusive access to the
1410 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
1411 * exclusive access is over. Data transfer must be done by spi_sync_locked
1412 * and spi_async_locked calls when the SPI bus lock is held.
1413 *
1414 * It returns zero on success, else a negative error code.
1415 */
1416int spi_bus_lock(struct spi_master *master)
1417{
1418 unsigned long flags;
1419
1420 mutex_lock(&master->bus_lock_mutex);
1421
1422 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
1423 master->bus_lock_flag = 1;
1424 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
1425
1426 /* mutex remains locked until spi_bus_unlock is called */
1427
1428 return 0;
1429}
1430EXPORT_SYMBOL_GPL(spi_bus_lock);
1431
1432/**
1433 * spi_bus_unlock - release the lock for exclusive SPI bus usage
1434 * @master: SPI bus master that was locked for exclusive bus access
1435 * Context: can sleep
1436 *
1437 * This call may only be used from a context that may sleep. The sleep
1438 * is non-interruptible, and has no timeout.
1439 *
1440 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
1441 * call.
1442 *
1443 * It returns zero on success, else a negative error code.
1444 */
1445int spi_bus_unlock(struct spi_master *master)
1446{
1447 master->bus_lock_flag = 0;
1448
1449 mutex_unlock(&master->bus_lock_mutex);
1450
1451 return 0;
1452}
1453EXPORT_SYMBOL_GPL(spi_bus_unlock);
1454
David Brownella9948b62006-04-02 10:37:40 -08001455/* portable code must never pass more than 32 bytes */
1456#define SPI_BUFSIZ max(32,SMP_CACHE_BYTES)
David Brownell8ae12a02006-01-08 13:34:19 -08001457
1458static u8 *buf;
1459
1460/**
1461 * spi_write_then_read - SPI synchronous write followed by read
1462 * @spi: device with which data will be exchanged
1463 * @txbuf: data to be written (need not be dma-safe)
1464 * @n_tx: size of txbuf, in bytes
Jiri Pirko27570492009-06-17 16:26:06 -07001465 * @rxbuf: buffer into which data will be read (need not be dma-safe)
1466 * @n_rx: size of rxbuf, in bytes
David Brownell33e34dc2007-05-08 00:32:21 -07001467 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -08001468 *
1469 * This performs a half duplex MicroWire style transaction with the
1470 * device, sending txbuf and then reading rxbuf. The return value
1471 * is zero for success, else a negative errno status code.
David Brownellb8852442006-01-08 13:34:23 -08001472 * This call may only be used from a context that may sleep.
David Brownell8ae12a02006-01-08 13:34:19 -08001473 *
David Brownell0c868462006-01-08 13:34:25 -08001474 * Parameters to this routine are always copied using a small buffer;
David Brownell33e34dc2007-05-08 00:32:21 -07001475 * portable code should never use this for more than 32 bytes.
1476 * Performance-sensitive or bulk transfer code should instead use
David Brownell0c868462006-01-08 13:34:25 -08001477 * spi_{async,sync}() calls with dma-safe buffers.
David Brownell8ae12a02006-01-08 13:34:19 -08001478 */
1479int spi_write_then_read(struct spi_device *spi,
Mark Brown0c4a1592011-05-11 00:09:30 +02001480 const void *txbuf, unsigned n_tx,
1481 void *rxbuf, unsigned n_rx)
David Brownell8ae12a02006-01-08 13:34:19 -08001482{
David Brownell068f4072007-12-04 23:45:09 -08001483 static DEFINE_MUTEX(lock);
David Brownell8ae12a02006-01-08 13:34:19 -08001484
1485 int status;
1486 struct spi_message message;
David Brownellbdff5492009-04-13 14:39:57 -07001487 struct spi_transfer x[2];
David Brownell8ae12a02006-01-08 13:34:19 -08001488 u8 *local_buf;
1489
1490 /* Use preallocated DMA-safe buffer. We can't avoid copying here,
1491 * (as a pure convenience thing), but we can keep heap costs
1492 * out of the hot path ...
1493 */
1494 if ((n_tx + n_rx) > SPI_BUFSIZ)
1495 return -EINVAL;
1496
Vitaly Wool8275c642006-01-08 13:34:28 -08001497 spi_message_init(&message);
David Brownellbdff5492009-04-13 14:39:57 -07001498 memset(x, 0, sizeof x);
1499 if (n_tx) {
1500 x[0].len = n_tx;
1501 spi_message_add_tail(&x[0], &message);
1502 }
1503 if (n_rx) {
1504 x[1].len = n_rx;
1505 spi_message_add_tail(&x[1], &message);
1506 }
Vitaly Wool8275c642006-01-08 13:34:28 -08001507
David Brownell8ae12a02006-01-08 13:34:19 -08001508 /* ... unless someone else is using the pre-allocated buffer */
David Brownell068f4072007-12-04 23:45:09 -08001509 if (!mutex_trylock(&lock)) {
David Brownell8ae12a02006-01-08 13:34:19 -08001510 local_buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
1511 if (!local_buf)
1512 return -ENOMEM;
1513 } else
1514 local_buf = buf;
1515
David Brownell8ae12a02006-01-08 13:34:19 -08001516 memcpy(local_buf, txbuf, n_tx);
David Brownellbdff5492009-04-13 14:39:57 -07001517 x[0].tx_buf = local_buf;
1518 x[1].rx_buf = local_buf + n_tx;
David Brownell8ae12a02006-01-08 13:34:19 -08001519
1520 /* do the i/o */
David Brownell8ae12a02006-01-08 13:34:19 -08001521 status = spi_sync(spi, &message);
Marc Pignat9b938b72007-12-04 23:45:10 -08001522 if (status == 0)
David Brownellbdff5492009-04-13 14:39:57 -07001523 memcpy(rxbuf, x[1].rx_buf, n_rx);
David Brownell8ae12a02006-01-08 13:34:19 -08001524
David Brownellbdff5492009-04-13 14:39:57 -07001525 if (x[0].tx_buf == buf)
David Brownell068f4072007-12-04 23:45:09 -08001526 mutex_unlock(&lock);
David Brownell8ae12a02006-01-08 13:34:19 -08001527 else
1528 kfree(local_buf);
1529
1530 return status;
1531}
1532EXPORT_SYMBOL_GPL(spi_write_then_read);
1533
1534/*-------------------------------------------------------------------------*/
1535
1536static int __init spi_init(void)
1537{
David Brownellb8852442006-01-08 13:34:23 -08001538 int status;
David Brownell8ae12a02006-01-08 13:34:19 -08001539
Christoph Lametere94b1762006-12-06 20:33:17 -08001540 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
David Brownellb8852442006-01-08 13:34:23 -08001541 if (!buf) {
1542 status = -ENOMEM;
1543 goto err0;
1544 }
1545
1546 status = bus_register(&spi_bus_type);
1547 if (status < 0)
1548 goto err1;
1549
1550 status = class_register(&spi_master_class);
1551 if (status < 0)
1552 goto err2;
David Brownell8ae12a02006-01-08 13:34:19 -08001553 return 0;
David Brownellb8852442006-01-08 13:34:23 -08001554
1555err2:
1556 bus_unregister(&spi_bus_type);
1557err1:
1558 kfree(buf);
1559 buf = NULL;
1560err0:
1561 return status;
David Brownell8ae12a02006-01-08 13:34:19 -08001562}
David Brownellb8852442006-01-08 13:34:23 -08001563
David Brownell8ae12a02006-01-08 13:34:19 -08001564/* board_info is normally registered in arch_initcall(),
1565 * but even essential drivers wait till later
David Brownellb8852442006-01-08 13:34:23 -08001566 *
1567 * REVISIT only boardinfo really needs static linking. the rest (device and
1568 * driver registration) _could_ be dynamically linked (modular) ... costs
1569 * include needing to have boardinfo data structures be much more public.
David Brownell8ae12a02006-01-08 13:34:19 -08001570 */
David Brownell673c0c02008-10-15 22:02:46 -07001571postcore_initcall(spi_init);
David Brownell8ae12a02006-01-08 13:34:19 -08001572