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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
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19 */
20
David Brownell8ae12a02006-01-08 13:34:19 -080021#include <linux/kernel.h>
22#include <linux/device.h>
23#include <linux/init.h>
24#include <linux/cache.h>
Matthias Kaehlcke94040822007-07-17 04:04:16 -070025#include <linux/mutex.h>
Sinan Akman2b7a32f2010-10-02 21:28:29 -060026#include <linux/of_device.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090027#include <linux/slab.h>
Anton Vorontsove0626e32009-09-22 16:46:08 -070028#include <linux/mod_devicetable.h>
David Brownell8ae12a02006-01-08 13:34:19 -080029#include <linux/spi/spi.h>
Anatolij Gustschin12b15e82010-07-27 22:35:58 +020030#include <linux/of_spi.h>
Mark Brown3ae22e82010-12-25 15:32:27 +010031#include <linux/pm_runtime.h>
Paul Gortmaker025ed132011-07-10 12:57:55 -040032#include <linux/export.h>
Linus Walleijffbbdd212012-02-22 10:05:38 +010033#include <linux/sched.h>
34#include <linux/delay.h>
35#include <linux/kthread.h>
David Brownell8ae12a02006-01-08 13:34:19 -080036
David Brownell8ae12a02006-01-08 13:34:19 -080037static void spidev_release(struct device *dev)
38{
Hans-Peter Nilsson0ffa0282007-02-12 00:52:45 -080039 struct spi_device *spi = to_spi_device(dev);
David Brownell8ae12a02006-01-08 13:34:19 -080040
41 /* spi masters may cleanup for released devices */
42 if (spi->master->cleanup)
43 spi->master->cleanup(spi);
44
David Brownell0c868462006-01-08 13:34:25 -080045 spi_master_put(spi->master);
Roman Tereshonkov07a389f2010-04-12 09:56:35 +000046 kfree(spi);
David Brownell8ae12a02006-01-08 13:34:19 -080047}
48
49static ssize_t
50modalias_show(struct device *dev, struct device_attribute *a, char *buf)
51{
52 const struct spi_device *spi = to_spi_device(dev);
53
Kay Sievers35f74fc2009-01-06 10:44:37 -080054 return sprintf(buf, "%s\n", spi->modalias);
David Brownell8ae12a02006-01-08 13:34:19 -080055}
56
57static struct device_attribute spi_dev_attrs[] = {
58 __ATTR_RO(modalias),
59 __ATTR_NULL,
60};
61
62/* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
63 * and the sysfs version makes coldplug work too.
64 */
65
Anton Vorontsov75368bf2009-09-22 16:46:04 -070066static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
67 const struct spi_device *sdev)
68{
69 while (id->name[0]) {
70 if (!strcmp(sdev->modalias, id->name))
71 return id;
72 id++;
73 }
74 return NULL;
75}
76
77const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
78{
79 const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
80
81 return spi_match_id(sdrv->id_table, sdev);
82}
83EXPORT_SYMBOL_GPL(spi_get_device_id);
84
David Brownell8ae12a02006-01-08 13:34:19 -080085static int spi_match_device(struct device *dev, struct device_driver *drv)
86{
87 const struct spi_device *spi = to_spi_device(dev);
Anton Vorontsov75368bf2009-09-22 16:46:04 -070088 const struct spi_driver *sdrv = to_spi_driver(drv);
89
Sinan Akman2b7a32f2010-10-02 21:28:29 -060090 /* Attempt an OF style match */
91 if (of_driver_match_device(dev, drv))
92 return 1;
93
Anton Vorontsov75368bf2009-09-22 16:46:04 -070094 if (sdrv->id_table)
95 return !!spi_match_id(sdrv->id_table, spi);
David Brownell8ae12a02006-01-08 13:34:19 -080096
Kay Sievers35f74fc2009-01-06 10:44:37 -080097 return strcmp(spi->modalias, drv->name) == 0;
David Brownell8ae12a02006-01-08 13:34:19 -080098}
99
Kay Sievers7eff2e72007-08-14 15:15:12 +0200100static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
David Brownell8ae12a02006-01-08 13:34:19 -0800101{
102 const struct spi_device *spi = to_spi_device(dev);
103
Anton Vorontsove0626e32009-09-22 16:46:08 -0700104 add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
David Brownell8ae12a02006-01-08 13:34:19 -0800105 return 0;
106}
107
Mark Brown3ae22e82010-12-25 15:32:27 +0100108#ifdef CONFIG_PM_SLEEP
109static int spi_legacy_suspend(struct device *dev, pm_message_t message)
David Brownell8ae12a02006-01-08 13:34:19 -0800110{
David Brownell3c724262008-02-06 01:38:10 -0800111 int value = 0;
David Brownellb8852442006-01-08 13:34:23 -0800112 struct spi_driver *drv = to_spi_driver(dev->driver);
David Brownell8ae12a02006-01-08 13:34:19 -0800113
David Brownell8ae12a02006-01-08 13:34:19 -0800114 /* suspend will stop irqs and dma; no more i/o */
David Brownell3c724262008-02-06 01:38:10 -0800115 if (drv) {
116 if (drv->suspend)
117 value = drv->suspend(to_spi_device(dev), message);
118 else
119 dev_dbg(dev, "... can't suspend\n");
120 }
David Brownell8ae12a02006-01-08 13:34:19 -0800121 return value;
122}
123
Mark Brown3ae22e82010-12-25 15:32:27 +0100124static int spi_legacy_resume(struct device *dev)
David Brownell8ae12a02006-01-08 13:34:19 -0800125{
David Brownell3c724262008-02-06 01:38:10 -0800126 int value = 0;
David Brownellb8852442006-01-08 13:34:23 -0800127 struct spi_driver *drv = to_spi_driver(dev->driver);
David Brownell8ae12a02006-01-08 13:34:19 -0800128
David Brownell8ae12a02006-01-08 13:34:19 -0800129 /* resume may restart the i/o queue */
David Brownell3c724262008-02-06 01:38:10 -0800130 if (drv) {
131 if (drv->resume)
132 value = drv->resume(to_spi_device(dev));
133 else
134 dev_dbg(dev, "... can't resume\n");
135 }
David Brownell8ae12a02006-01-08 13:34:19 -0800136 return value;
137}
138
Mark Brown3ae22e82010-12-25 15:32:27 +0100139static int spi_pm_suspend(struct device *dev)
140{
141 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
142
143 if (pm)
144 return pm_generic_suspend(dev);
145 else
146 return spi_legacy_suspend(dev, PMSG_SUSPEND);
147}
148
149static int spi_pm_resume(struct device *dev)
150{
151 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
152
153 if (pm)
154 return pm_generic_resume(dev);
155 else
156 return spi_legacy_resume(dev);
157}
158
159static int spi_pm_freeze(struct device *dev)
160{
161 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
162
163 if (pm)
164 return pm_generic_freeze(dev);
165 else
166 return spi_legacy_suspend(dev, PMSG_FREEZE);
167}
168
169static int spi_pm_thaw(struct device *dev)
170{
171 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
172
173 if (pm)
174 return pm_generic_thaw(dev);
175 else
176 return spi_legacy_resume(dev);
177}
178
179static int spi_pm_poweroff(struct device *dev)
180{
181 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
182
183 if (pm)
184 return pm_generic_poweroff(dev);
185 else
186 return spi_legacy_suspend(dev, PMSG_HIBERNATE);
187}
188
189static int spi_pm_restore(struct device *dev)
190{
191 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
192
193 if (pm)
194 return pm_generic_restore(dev);
195 else
196 return spi_legacy_resume(dev);
197}
David Brownell8ae12a02006-01-08 13:34:19 -0800198#else
Mark Brown3ae22e82010-12-25 15:32:27 +0100199#define spi_pm_suspend NULL
200#define spi_pm_resume NULL
201#define spi_pm_freeze NULL
202#define spi_pm_thaw NULL
203#define spi_pm_poweroff NULL
204#define spi_pm_restore NULL
David Brownell8ae12a02006-01-08 13:34:19 -0800205#endif
206
Mark Brown3ae22e82010-12-25 15:32:27 +0100207static const struct dev_pm_ops spi_pm = {
208 .suspend = spi_pm_suspend,
209 .resume = spi_pm_resume,
210 .freeze = spi_pm_freeze,
211 .thaw = spi_pm_thaw,
212 .poweroff = spi_pm_poweroff,
213 .restore = spi_pm_restore,
214 SET_RUNTIME_PM_OPS(
215 pm_generic_runtime_suspend,
216 pm_generic_runtime_resume,
217 pm_generic_runtime_idle
218 )
219};
220
David Brownell8ae12a02006-01-08 13:34:19 -0800221struct bus_type spi_bus_type = {
222 .name = "spi",
223 .dev_attrs = spi_dev_attrs,
224 .match = spi_match_device,
225 .uevent = spi_uevent,
Mark Brown3ae22e82010-12-25 15:32:27 +0100226 .pm = &spi_pm,
David Brownell8ae12a02006-01-08 13:34:19 -0800227};
228EXPORT_SYMBOL_GPL(spi_bus_type);
229
David Brownellb8852442006-01-08 13:34:23 -0800230
231static int spi_drv_probe(struct device *dev)
232{
233 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
234
235 return sdrv->probe(to_spi_device(dev));
236}
237
238static int spi_drv_remove(struct device *dev)
239{
240 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
241
242 return sdrv->remove(to_spi_device(dev));
243}
244
245static void spi_drv_shutdown(struct device *dev)
246{
247 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
248
249 sdrv->shutdown(to_spi_device(dev));
250}
251
David Brownell33e34dc2007-05-08 00:32:21 -0700252/**
253 * spi_register_driver - register a SPI driver
254 * @sdrv: the driver to register
255 * Context: can sleep
256 */
David Brownellb8852442006-01-08 13:34:23 -0800257int spi_register_driver(struct spi_driver *sdrv)
258{
259 sdrv->driver.bus = &spi_bus_type;
260 if (sdrv->probe)
261 sdrv->driver.probe = spi_drv_probe;
262 if (sdrv->remove)
263 sdrv->driver.remove = spi_drv_remove;
264 if (sdrv->shutdown)
265 sdrv->driver.shutdown = spi_drv_shutdown;
266 return driver_register(&sdrv->driver);
267}
268EXPORT_SYMBOL_GPL(spi_register_driver);
269
David Brownell8ae12a02006-01-08 13:34:19 -0800270/*-------------------------------------------------------------------------*/
271
272/* SPI devices should normally not be created by SPI device drivers; that
273 * would make them board-specific. Similarly with SPI master drivers.
274 * Device registration normally goes into like arch/.../mach.../board-YYY.c
275 * with other readonly (flashable) information about mainboard devices.
276 */
277
278struct boardinfo {
279 struct list_head list;
Feng Tang2b9603a2010-08-02 15:52:15 +0800280 struct spi_board_info board_info;
David Brownell8ae12a02006-01-08 13:34:19 -0800281};
282
283static LIST_HEAD(board_list);
Feng Tang2b9603a2010-08-02 15:52:15 +0800284static LIST_HEAD(spi_master_list);
285
286/*
287 * Used to protect add/del opertion for board_info list and
288 * spi_master list, and their matching process
289 */
Matthias Kaehlcke94040822007-07-17 04:04:16 -0700290static DEFINE_MUTEX(board_lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800291
Grant Likelydc87c982008-05-15 16:50:22 -0600292/**
293 * spi_alloc_device - Allocate a new SPI device
294 * @master: Controller to which device is connected
295 * Context: can sleep
296 *
297 * Allows a driver to allocate and initialize a spi_device without
298 * registering it immediately. This allows a driver to directly
299 * fill the spi_device with device parameters before calling
300 * spi_add_device() on it.
301 *
302 * Caller is responsible to call spi_add_device() on the returned
303 * spi_device structure to add it to the SPI master. If the caller
304 * needs to discard the spi_device without adding it, then it should
305 * call spi_dev_put() on it.
306 *
307 * Returns a pointer to the new device, or NULL.
308 */
309struct spi_device *spi_alloc_device(struct spi_master *master)
310{
311 struct spi_device *spi;
312 struct device *dev = master->dev.parent;
313
314 if (!spi_master_get(master))
315 return NULL;
316
317 spi = kzalloc(sizeof *spi, GFP_KERNEL);
318 if (!spi) {
319 dev_err(dev, "cannot alloc spi_device\n");
320 spi_master_put(master);
321 return NULL;
322 }
323
324 spi->master = master;
Laurent Pinchart178db7d2011-12-12 01:15:06 +0100325 spi->dev.parent = &master->dev;
Grant Likelydc87c982008-05-15 16:50:22 -0600326 spi->dev.bus = &spi_bus_type;
327 spi->dev.release = spidev_release;
328 device_initialize(&spi->dev);
329 return spi;
330}
331EXPORT_SYMBOL_GPL(spi_alloc_device);
332
333/**
334 * spi_add_device - Add spi_device allocated with spi_alloc_device
335 * @spi: spi_device to register
336 *
337 * Companion function to spi_alloc_device. Devices allocated with
338 * spi_alloc_device can be added onto the spi bus with this function.
339 *
David Brownelle48880e2008-08-15 00:40:44 -0700340 * Returns 0 on success; negative errno on failure
Grant Likelydc87c982008-05-15 16:50:22 -0600341 */
342int spi_add_device(struct spi_device *spi)
343{
David Brownelle48880e2008-08-15 00:40:44 -0700344 static DEFINE_MUTEX(spi_add_lock);
Grant Likelydc87c982008-05-15 16:50:22 -0600345 struct device *dev = spi->master->dev.parent;
Roman Tereshonkov8ec130a2010-04-16 09:52:59 +0000346 struct device *d;
Grant Likelydc87c982008-05-15 16:50:22 -0600347 int status;
348
349 /* Chipselects are numbered 0..max; validate. */
350 if (spi->chip_select >= spi->master->num_chipselect) {
351 dev_err(dev, "cs%d >= max %d\n",
352 spi->chip_select,
353 spi->master->num_chipselect);
354 return -EINVAL;
355 }
356
357 /* Set the bus ID string */
Kay Sievers35f74fc2009-01-06 10:44:37 -0800358 dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
Grant Likelydc87c982008-05-15 16:50:22 -0600359 spi->chip_select);
360
David Brownelle48880e2008-08-15 00:40:44 -0700361
362 /* We need to make sure there's no other device with this
363 * chipselect **BEFORE** we call setup(), else we'll trash
364 * its configuration. Lock against concurrent add() calls.
365 */
366 mutex_lock(&spi_add_lock);
367
Roman Tereshonkov8ec130a2010-04-16 09:52:59 +0000368 d = bus_find_device_by_name(&spi_bus_type, NULL, dev_name(&spi->dev));
369 if (d != NULL) {
David Brownelle48880e2008-08-15 00:40:44 -0700370 dev_err(dev, "chipselect %d already in use\n",
371 spi->chip_select);
Roman Tereshonkov8ec130a2010-04-16 09:52:59 +0000372 put_device(d);
David Brownelle48880e2008-08-15 00:40:44 -0700373 status = -EBUSY;
374 goto done;
375 }
376
377 /* Drivers may modify this initial i/o setup, but will
378 * normally rely on the device being setup. Devices
379 * using SPI_CS_HIGH can't coexist well otherwise...
380 */
David Brownell7d077192009-06-17 16:26:03 -0700381 status = spi_setup(spi);
Grant Likelydc87c982008-05-15 16:50:22 -0600382 if (status < 0) {
Linus Walleijeb288a12010-10-21 21:06:44 +0200383 dev_err(dev, "can't setup %s, status %d\n",
384 dev_name(&spi->dev), status);
David Brownelle48880e2008-08-15 00:40:44 -0700385 goto done;
Grant Likelydc87c982008-05-15 16:50:22 -0600386 }
387
David Brownelle48880e2008-08-15 00:40:44 -0700388 /* Device may be bound to an active driver when this returns */
Grant Likelydc87c982008-05-15 16:50:22 -0600389 status = device_add(&spi->dev);
David Brownelle48880e2008-08-15 00:40:44 -0700390 if (status < 0)
Linus Walleijeb288a12010-10-21 21:06:44 +0200391 dev_err(dev, "can't add %s, status %d\n",
392 dev_name(&spi->dev), status);
David Brownelle48880e2008-08-15 00:40:44 -0700393 else
Kay Sievers35f74fc2009-01-06 10:44:37 -0800394 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
Grant Likelydc87c982008-05-15 16:50:22 -0600395
David Brownelle48880e2008-08-15 00:40:44 -0700396done:
397 mutex_unlock(&spi_add_lock);
398 return status;
Grant Likelydc87c982008-05-15 16:50:22 -0600399}
400EXPORT_SYMBOL_GPL(spi_add_device);
David Brownell8ae12a02006-01-08 13:34:19 -0800401
David Brownell33e34dc2007-05-08 00:32:21 -0700402/**
403 * spi_new_device - instantiate one new SPI device
404 * @master: Controller to which device is connected
405 * @chip: Describes the SPI device
406 * Context: can sleep
407 *
408 * On typical mainboards, this is purely internal; and it's not needed
David Brownell8ae12a02006-01-08 13:34:19 -0800409 * after board init creates the hard-wired devices. Some development
410 * platforms may not be able to use spi_register_board_info though, and
411 * this is exported so that for example a USB or parport based adapter
412 * driver could add devices (which it would learn about out-of-band).
David Brownell082c8cb2007-07-31 00:39:45 -0700413 *
414 * Returns the new device, or NULL.
David Brownell8ae12a02006-01-08 13:34:19 -0800415 */
Adrian Bunke9d5a462007-03-26 21:32:23 -0800416struct spi_device *spi_new_device(struct spi_master *master,
417 struct spi_board_info *chip)
David Brownell8ae12a02006-01-08 13:34:19 -0800418{
419 struct spi_device *proxy;
David Brownell8ae12a02006-01-08 13:34:19 -0800420 int status;
421
David Brownell082c8cb2007-07-31 00:39:45 -0700422 /* NOTE: caller did any chip->bus_num checks necessary.
423 *
424 * Also, unless we change the return value convention to use
425 * error-or-pointer (not NULL-or-pointer), troubleshootability
426 * suggests syslogged diagnostics are best here (ugh).
427 */
428
Grant Likelydc87c982008-05-15 16:50:22 -0600429 proxy = spi_alloc_device(master);
430 if (!proxy)
David Brownell8ae12a02006-01-08 13:34:19 -0800431 return NULL;
432
Grant Likely102eb972008-07-23 21:29:55 -0700433 WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
434
David Brownell8ae12a02006-01-08 13:34:19 -0800435 proxy->chip_select = chip->chip_select;
436 proxy->max_speed_hz = chip->max_speed_hz;
David Brownell980a01c2006-06-28 07:47:15 -0700437 proxy->mode = chip->mode;
David Brownell8ae12a02006-01-08 13:34:19 -0800438 proxy->irq = chip->irq;
Grant Likely102eb972008-07-23 21:29:55 -0700439 strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
David Brownell8ae12a02006-01-08 13:34:19 -0800440 proxy->dev.platform_data = (void *) chip->platform_data;
441 proxy->controller_data = chip->controller_data;
442 proxy->controller_state = NULL;
David Brownell8ae12a02006-01-08 13:34:19 -0800443
Grant Likelydc87c982008-05-15 16:50:22 -0600444 status = spi_add_device(proxy);
David Brownell8ae12a02006-01-08 13:34:19 -0800445 if (status < 0) {
Grant Likelydc87c982008-05-15 16:50:22 -0600446 spi_dev_put(proxy);
447 return NULL;
David Brownell8ae12a02006-01-08 13:34:19 -0800448 }
449
David Brownell8ae12a02006-01-08 13:34:19 -0800450 return proxy;
451}
452EXPORT_SYMBOL_GPL(spi_new_device);
453
Feng Tang2b9603a2010-08-02 15:52:15 +0800454static void spi_match_master_to_boardinfo(struct spi_master *master,
455 struct spi_board_info *bi)
456{
457 struct spi_device *dev;
458
459 if (master->bus_num != bi->bus_num)
460 return;
461
462 dev = spi_new_device(master, bi);
463 if (!dev)
464 dev_err(master->dev.parent, "can't create new device for %s\n",
465 bi->modalias);
466}
467
David Brownell33e34dc2007-05-08 00:32:21 -0700468/**
469 * spi_register_board_info - register SPI devices for a given board
470 * @info: array of chip descriptors
471 * @n: how many descriptors are provided
472 * Context: can sleep
473 *
David Brownell8ae12a02006-01-08 13:34:19 -0800474 * Board-specific early init code calls this (probably during arch_initcall)
475 * with segments of the SPI device table. Any device nodes are created later,
476 * after the relevant parent SPI controller (bus_num) is defined. We keep
477 * this table of devices forever, so that reloading a controller driver will
478 * not make Linux forget about these hard-wired devices.
479 *
480 * Other code can also call this, e.g. a particular add-on board might provide
481 * SPI devices through its expansion connector, so code initializing that board
482 * would naturally declare its SPI devices.
483 *
484 * The board info passed can safely be __initdata ... but be careful of
485 * any embedded pointers (platform_data, etc), they're copied as-is.
486 */
Mark Brown690fb112012-02-17 16:23:29 -0800487int __devinit
David Brownell8ae12a02006-01-08 13:34:19 -0800488spi_register_board_info(struct spi_board_info const *info, unsigned n)
489{
Feng Tang2b9603a2010-08-02 15:52:15 +0800490 struct boardinfo *bi;
491 int i;
David Brownell8ae12a02006-01-08 13:34:19 -0800492
Feng Tang2b9603a2010-08-02 15:52:15 +0800493 bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
David Brownell8ae12a02006-01-08 13:34:19 -0800494 if (!bi)
495 return -ENOMEM;
David Brownell8ae12a02006-01-08 13:34:19 -0800496
Feng Tang2b9603a2010-08-02 15:52:15 +0800497 for (i = 0; i < n; i++, bi++, info++) {
498 struct spi_master *master;
David Brownell8ae12a02006-01-08 13:34:19 -0800499
Feng Tang2b9603a2010-08-02 15:52:15 +0800500 memcpy(&bi->board_info, info, sizeof(*info));
501 mutex_lock(&board_lock);
502 list_add_tail(&bi->list, &board_list);
503 list_for_each_entry(master, &spi_master_list, list)
504 spi_match_master_to_boardinfo(master, &bi->board_info);
505 mutex_unlock(&board_lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800506 }
Feng Tang2b9603a2010-08-02 15:52:15 +0800507
508 return 0;
David Brownell8ae12a02006-01-08 13:34:19 -0800509}
510
511/*-------------------------------------------------------------------------*/
512
Linus Walleijffbbdd212012-02-22 10:05:38 +0100513/**
514 * spi_pump_messages - kthread work function which processes spi message queue
515 * @work: pointer to kthread work struct contained in the master struct
516 *
517 * This function checks if there is any spi message in the queue that
518 * needs processing and if so call out to the driver to initialize hardware
519 * and transfer each message.
520 *
521 */
522static void spi_pump_messages(struct kthread_work *work)
523{
524 struct spi_master *master =
525 container_of(work, struct spi_master, pump_messages);
526 unsigned long flags;
527 bool was_busy = false;
528 int ret;
529
530 /* Lock queue and check for queue work */
531 spin_lock_irqsave(&master->queue_lock, flags);
532 if (list_empty(&master->queue) || !master->running) {
533 if (master->busy) {
534 ret = master->unprepare_transfer_hardware(master);
535 if (ret) {
Dan Carpenter9af4acc2012-03-10 11:57:29 +0300536 spin_unlock_irqrestore(&master->queue_lock, flags);
Linus Walleijffbbdd212012-02-22 10:05:38 +0100537 dev_err(&master->dev,
538 "failed to unprepare transfer hardware\n");
539 return;
540 }
541 }
542 master->busy = false;
543 spin_unlock_irqrestore(&master->queue_lock, flags);
544 return;
545 }
546
547 /* Make sure we are not already running a message */
548 if (master->cur_msg) {
549 spin_unlock_irqrestore(&master->queue_lock, flags);
550 return;
551 }
552 /* Extract head of queue */
553 master->cur_msg =
554 list_entry(master->queue.next, struct spi_message, queue);
555
556 list_del_init(&master->cur_msg->queue);
557 if (master->busy)
558 was_busy = true;
559 else
560 master->busy = true;
561 spin_unlock_irqrestore(&master->queue_lock, flags);
562
563 if (!was_busy) {
564 ret = master->prepare_transfer_hardware(master);
565 if (ret) {
566 dev_err(&master->dev,
567 "failed to prepare transfer hardware\n");
568 return;
569 }
570 }
571
572 ret = master->transfer_one_message(master, master->cur_msg);
573 if (ret) {
574 dev_err(&master->dev,
575 "failed to transfer one message from queue\n");
576 return;
577 }
578}
579
580static int spi_init_queue(struct spi_master *master)
581{
582 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
583
584 INIT_LIST_HEAD(&master->queue);
585 spin_lock_init(&master->queue_lock);
586
587 master->running = false;
588 master->busy = false;
589
590 init_kthread_worker(&master->kworker);
591 master->kworker_task = kthread_run(kthread_worker_fn,
592 &master->kworker,
593 dev_name(&master->dev));
594 if (IS_ERR(master->kworker_task)) {
595 dev_err(&master->dev, "failed to create message pump task\n");
596 return -ENOMEM;
597 }
598 init_kthread_work(&master->pump_messages, spi_pump_messages);
599
600 /*
601 * Master config will indicate if this controller should run the
602 * message pump with high (realtime) priority to reduce the transfer
603 * latency on the bus by minimising the delay between a transfer
604 * request and the scheduling of the message pump thread. Without this
605 * setting the message pump thread will remain at default priority.
606 */
607 if (master->rt) {
608 dev_info(&master->dev,
609 "will run message pump with realtime priority\n");
610 sched_setscheduler(master->kworker_task, SCHED_FIFO, &param);
611 }
612
613 return 0;
614}
615
616/**
617 * spi_get_next_queued_message() - called by driver to check for queued
618 * messages
619 * @master: the master to check for queued messages
620 *
621 * If there are more messages in the queue, the next message is returned from
622 * this call.
623 */
624struct spi_message *spi_get_next_queued_message(struct spi_master *master)
625{
626 struct spi_message *next;
627 unsigned long flags;
628
629 /* get a pointer to the next message, if any */
630 spin_lock_irqsave(&master->queue_lock, flags);
631 if (list_empty(&master->queue))
632 next = NULL;
633 else
634 next = list_entry(master->queue.next,
635 struct spi_message, queue);
636 spin_unlock_irqrestore(&master->queue_lock, flags);
637
638 return next;
639}
640EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
641
642/**
643 * spi_finalize_current_message() - the current message is complete
644 * @master: the master to return the message to
645 *
646 * Called by the driver to notify the core that the message in the front of the
647 * queue is complete and can be removed from the queue.
648 */
649void spi_finalize_current_message(struct spi_master *master)
650{
651 struct spi_message *mesg;
652 unsigned long flags;
653
654 spin_lock_irqsave(&master->queue_lock, flags);
655 mesg = master->cur_msg;
656 master->cur_msg = NULL;
657
658 queue_kthread_work(&master->kworker, &master->pump_messages);
659 spin_unlock_irqrestore(&master->queue_lock, flags);
660
661 mesg->state = NULL;
662 if (mesg->complete)
663 mesg->complete(mesg->context);
664}
665EXPORT_SYMBOL_GPL(spi_finalize_current_message);
666
667static int spi_start_queue(struct spi_master *master)
668{
669 unsigned long flags;
670
671 spin_lock_irqsave(&master->queue_lock, flags);
672
673 if (master->running || master->busy) {
674 spin_unlock_irqrestore(&master->queue_lock, flags);
675 return -EBUSY;
676 }
677
678 master->running = true;
679 master->cur_msg = NULL;
680 spin_unlock_irqrestore(&master->queue_lock, flags);
681
682 queue_kthread_work(&master->kworker, &master->pump_messages);
683
684 return 0;
685}
686
687static int spi_stop_queue(struct spi_master *master)
688{
689 unsigned long flags;
690 unsigned limit = 500;
691 int ret = 0;
692
693 spin_lock_irqsave(&master->queue_lock, flags);
694
695 /*
696 * This is a bit lame, but is optimized for the common execution path.
697 * A wait_queue on the master->busy could be used, but then the common
698 * execution path (pump_messages) would be required to call wake_up or
699 * friends on every SPI message. Do this instead.
700 */
701 while ((!list_empty(&master->queue) || master->busy) && limit--) {
702 spin_unlock_irqrestore(&master->queue_lock, flags);
703 msleep(10);
704 spin_lock_irqsave(&master->queue_lock, flags);
705 }
706
707 if (!list_empty(&master->queue) || master->busy)
708 ret = -EBUSY;
709 else
710 master->running = false;
711
712 spin_unlock_irqrestore(&master->queue_lock, flags);
713
714 if (ret) {
715 dev_warn(&master->dev,
716 "could not stop message queue\n");
717 return ret;
718 }
719 return ret;
720}
721
722static int spi_destroy_queue(struct spi_master *master)
723{
724 int ret;
725
726 ret = spi_stop_queue(master);
727
728 /*
729 * flush_kthread_worker will block until all work is done.
730 * If the reason that stop_queue timed out is that the work will never
731 * finish, then it does no good to call flush/stop thread, so
732 * return anyway.
733 */
734 if (ret) {
735 dev_err(&master->dev, "problem destroying queue\n");
736 return ret;
737 }
738
739 flush_kthread_worker(&master->kworker);
740 kthread_stop(master->kworker_task);
741
742 return 0;
743}
744
745/**
746 * spi_queued_transfer - transfer function for queued transfers
747 * @spi: spi device which is requesting transfer
748 * @msg: spi message which is to handled is queued to driver queue
749 */
750static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
751{
752 struct spi_master *master = spi->master;
753 unsigned long flags;
754
755 spin_lock_irqsave(&master->queue_lock, flags);
756
757 if (!master->running) {
758 spin_unlock_irqrestore(&master->queue_lock, flags);
759 return -ESHUTDOWN;
760 }
761 msg->actual_length = 0;
762 msg->status = -EINPROGRESS;
763
764 list_add_tail(&msg->queue, &master->queue);
765 if (master->running && !master->busy)
766 queue_kthread_work(&master->kworker, &master->pump_messages);
767
768 spin_unlock_irqrestore(&master->queue_lock, flags);
769 return 0;
770}
771
772static int spi_master_initialize_queue(struct spi_master *master)
773{
774 int ret;
775
776 master->queued = true;
777 master->transfer = spi_queued_transfer;
778
779 /* Initialize and start queue */
780 ret = spi_init_queue(master);
781 if (ret) {
782 dev_err(&master->dev, "problem initializing queue\n");
783 goto err_init_queue;
784 }
785 ret = spi_start_queue(master);
786 if (ret) {
787 dev_err(&master->dev, "problem starting queue\n");
788 goto err_start_queue;
789 }
790
791 return 0;
792
793err_start_queue:
794err_init_queue:
795 spi_destroy_queue(master);
796 return ret;
797}
798
799/*-------------------------------------------------------------------------*/
800
Tony Jones49dce682007-10-16 01:27:48 -0700801static void spi_master_release(struct device *dev)
David Brownell8ae12a02006-01-08 13:34:19 -0800802{
803 struct spi_master *master;
804
Tony Jones49dce682007-10-16 01:27:48 -0700805 master = container_of(dev, struct spi_master, dev);
David Brownell8ae12a02006-01-08 13:34:19 -0800806 kfree(master);
807}
808
809static struct class spi_master_class = {
810 .name = "spi_master",
811 .owner = THIS_MODULE,
Tony Jones49dce682007-10-16 01:27:48 -0700812 .dev_release = spi_master_release,
David Brownell8ae12a02006-01-08 13:34:19 -0800813};
814
815
Linus Walleijffbbdd212012-02-22 10:05:38 +0100816
David Brownell8ae12a02006-01-08 13:34:19 -0800817/**
818 * spi_alloc_master - allocate SPI master controller
819 * @dev: the controller, possibly using the platform_bus
David Brownell33e34dc2007-05-08 00:32:21 -0700820 * @size: how much zeroed driver-private data to allocate; the pointer to this
Tony Jones49dce682007-10-16 01:27:48 -0700821 * memory is in the driver_data field of the returned device,
David Brownell0c868462006-01-08 13:34:25 -0800822 * accessible with spi_master_get_devdata().
David Brownell33e34dc2007-05-08 00:32:21 -0700823 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800824 *
825 * This call is used only by SPI master controller drivers, which are the
826 * only ones directly touching chip registers. It's how they allocate
dmitry pervushinba1a0512006-05-20 15:00:14 -0700827 * an spi_master structure, prior to calling spi_register_master().
David Brownell8ae12a02006-01-08 13:34:19 -0800828 *
829 * This must be called from context that can sleep. It returns the SPI
830 * master structure on success, else NULL.
831 *
832 * The caller is responsible for assigning the bus number and initializing
dmitry pervushinba1a0512006-05-20 15:00:14 -0700833 * the master's methods before calling spi_register_master(); and (after errors
Uwe Kleine-Königeb4af0f2012-02-23 10:40:14 +0100834 * adding the device) calling spi_master_put() and kfree() to prevent a memory
835 * leak.
David Brownell8ae12a02006-01-08 13:34:19 -0800836 */
Adrian Bunke9d5a462007-03-26 21:32:23 -0800837struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
David Brownell8ae12a02006-01-08 13:34:19 -0800838{
839 struct spi_master *master;
840
David Brownell0c868462006-01-08 13:34:25 -0800841 if (!dev)
842 return NULL;
843
Christoph Lametere94b1762006-12-06 20:33:17 -0800844 master = kzalloc(size + sizeof *master, GFP_KERNEL);
David Brownell8ae12a02006-01-08 13:34:19 -0800845 if (!master)
846 return NULL;
847
Tony Jones49dce682007-10-16 01:27:48 -0700848 device_initialize(&master->dev);
849 master->dev.class = &spi_master_class;
850 master->dev.parent = get_device(dev);
David Brownell0c868462006-01-08 13:34:25 -0800851 spi_master_set_devdata(master, &master[1]);
David Brownell8ae12a02006-01-08 13:34:19 -0800852
853 return master;
854}
855EXPORT_SYMBOL_GPL(spi_alloc_master);
856
857/**
858 * spi_register_master - register SPI master controller
859 * @master: initialized master, originally from spi_alloc_master()
David Brownell33e34dc2007-05-08 00:32:21 -0700860 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800861 *
862 * SPI master controllers connect to their drivers using some non-SPI bus,
863 * such as the platform bus. The final stage of probe() in that code
864 * includes calling spi_register_master() to hook up to this SPI bus glue.
865 *
866 * SPI controllers use board specific (often SOC specific) bus numbers,
867 * and board-specific addressing for SPI devices combines those numbers
868 * with chip select numbers. Since SPI does not directly support dynamic
869 * device identification, boards need configuration tables telling which
870 * chip is at which address.
871 *
872 * This must be called from context that can sleep. It returns zero on
873 * success, else a negative error code (dropping the master's refcount).
David Brownell0c868462006-01-08 13:34:25 -0800874 * After a successful return, the caller is responsible for calling
875 * spi_unregister_master().
David Brownell8ae12a02006-01-08 13:34:19 -0800876 */
Adrian Bunke9d5a462007-03-26 21:32:23 -0800877int spi_register_master(struct spi_master *master)
David Brownell8ae12a02006-01-08 13:34:19 -0800878{
David Brownelle44a45a2007-06-03 13:50:40 -0700879 static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
Tony Jones49dce682007-10-16 01:27:48 -0700880 struct device *dev = master->dev.parent;
Feng Tang2b9603a2010-08-02 15:52:15 +0800881 struct boardinfo *bi;
David Brownell8ae12a02006-01-08 13:34:19 -0800882 int status = -ENODEV;
883 int dynamic = 0;
884
David Brownell0c868462006-01-08 13:34:25 -0800885 if (!dev)
886 return -ENODEV;
887
David Brownell082c8cb2007-07-31 00:39:45 -0700888 /* even if it's just one always-selected device, there must
889 * be at least one chipselect
890 */
891 if (master->num_chipselect == 0)
892 return -EINVAL;
893
David Brownell8ae12a02006-01-08 13:34:19 -0800894 /* convention: dynamically assigned bus IDs count down from the max */
David Brownella020ed72006-04-03 15:49:04 -0700895 if (master->bus_num < 0) {
David Brownell082c8cb2007-07-31 00:39:45 -0700896 /* FIXME switch to an IDR based scheme, something like
897 * I2C now uses, so we can't run out of "dynamic" IDs
898 */
David Brownell8ae12a02006-01-08 13:34:19 -0800899 master->bus_num = atomic_dec_return(&dyn_bus_id);
David Brownellb8852442006-01-08 13:34:23 -0800900 dynamic = 1;
David Brownell8ae12a02006-01-08 13:34:19 -0800901 }
902
Ernst Schwabcf32b712010-06-28 17:49:29 -0700903 spin_lock_init(&master->bus_lock_spinlock);
904 mutex_init(&master->bus_lock_mutex);
905 master->bus_lock_flag = 0;
906
David Brownell8ae12a02006-01-08 13:34:19 -0800907 /* register the device, then userspace will see it.
908 * registration fails if the bus ID is in use.
909 */
Kay Sievers35f74fc2009-01-06 10:44:37 -0800910 dev_set_name(&master->dev, "spi%u", master->bus_num);
Tony Jones49dce682007-10-16 01:27:48 -0700911 status = device_add(&master->dev);
David Brownellb8852442006-01-08 13:34:23 -0800912 if (status < 0)
David Brownell8ae12a02006-01-08 13:34:19 -0800913 goto done;
Kay Sievers35f74fc2009-01-06 10:44:37 -0800914 dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
David Brownell8ae12a02006-01-08 13:34:19 -0800915 dynamic ? " (dynamic)" : "");
916
Linus Walleijffbbdd212012-02-22 10:05:38 +0100917 /* If we're using a queued driver, start the queue */
918 if (master->transfer)
919 dev_info(dev, "master is unqueued, this is deprecated\n");
920 else {
921 status = spi_master_initialize_queue(master);
922 if (status) {
923 device_unregister(&master->dev);
924 goto done;
925 }
926 }
927
Feng Tang2b9603a2010-08-02 15:52:15 +0800928 mutex_lock(&board_lock);
929 list_add_tail(&master->list, &spi_master_list);
930 list_for_each_entry(bi, &board_list, list)
931 spi_match_master_to_boardinfo(master, &bi->board_info);
932 mutex_unlock(&board_lock);
933
Anatolij Gustschin12b15e82010-07-27 22:35:58 +0200934 /* Register devices from the device tree */
935 of_register_spi_devices(master);
David Brownell8ae12a02006-01-08 13:34:19 -0800936done:
937 return status;
938}
939EXPORT_SYMBOL_GPL(spi_register_master);
940
David Lamparter34860082010-08-30 23:54:17 +0200941static int __unregister(struct device *dev, void *null)
David Brownell8ae12a02006-01-08 13:34:19 -0800942{
David Lamparter34860082010-08-30 23:54:17 +0200943 spi_unregister_device(to_spi_device(dev));
David Brownell8ae12a02006-01-08 13:34:19 -0800944 return 0;
945}
946
947/**
948 * spi_unregister_master - unregister SPI master controller
949 * @master: the master being unregistered
David Brownell33e34dc2007-05-08 00:32:21 -0700950 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800951 *
952 * This call is used only by SPI master controller drivers, which are the
953 * only ones directly touching chip registers.
954 *
955 * This must be called from context that can sleep.
956 */
957void spi_unregister_master(struct spi_master *master)
958{
Jeff Garzik89fc9a12006-12-06 20:35:35 -0800959 int dummy;
960
Linus Walleijffbbdd212012-02-22 10:05:38 +0100961 if (master->queued) {
962 if (spi_destroy_queue(master))
963 dev_err(&master->dev, "queue remove failed\n");
964 }
965
Feng Tang2b9603a2010-08-02 15:52:15 +0800966 mutex_lock(&board_lock);
967 list_del(&master->list);
968 mutex_unlock(&board_lock);
969
Sebastian Andrzej Siewior97dbf372010-12-21 17:24:31 -0800970 dummy = device_for_each_child(&master->dev, NULL, __unregister);
Tony Jones49dce682007-10-16 01:27:48 -0700971 device_unregister(&master->dev);
David Brownell8ae12a02006-01-08 13:34:19 -0800972}
973EXPORT_SYMBOL_GPL(spi_unregister_master);
974
Linus Walleijffbbdd212012-02-22 10:05:38 +0100975int spi_master_suspend(struct spi_master *master)
976{
977 int ret;
978
979 /* Basically no-ops for non-queued masters */
980 if (!master->queued)
981 return 0;
982
983 ret = spi_stop_queue(master);
984 if (ret)
985 dev_err(&master->dev, "queue stop failed\n");
986
987 return ret;
988}
989EXPORT_SYMBOL_GPL(spi_master_suspend);
990
991int spi_master_resume(struct spi_master *master)
992{
993 int ret;
994
995 if (!master->queued)
996 return 0;
997
998 ret = spi_start_queue(master);
999 if (ret)
1000 dev_err(&master->dev, "queue restart failed\n");
1001
1002 return ret;
1003}
1004EXPORT_SYMBOL_GPL(spi_master_resume);
1005
Dave Young5ed2c832008-01-22 15:14:18 +08001006static int __spi_master_match(struct device *dev, void *data)
1007{
1008 struct spi_master *m;
1009 u16 *bus_num = data;
1010
1011 m = container_of(dev, struct spi_master, dev);
1012 return m->bus_num == *bus_num;
1013}
1014
David Brownell8ae12a02006-01-08 13:34:19 -08001015/**
1016 * spi_busnum_to_master - look up master associated with bus_num
1017 * @bus_num: the master's bus number
David Brownell33e34dc2007-05-08 00:32:21 -07001018 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -08001019 *
1020 * This call may be used with devices that are registered after
1021 * arch init time. It returns a refcounted pointer to the relevant
1022 * spi_master (which the caller must release), or NULL if there is
1023 * no such master registered.
1024 */
1025struct spi_master *spi_busnum_to_master(u16 bus_num)
1026{
Tony Jones49dce682007-10-16 01:27:48 -07001027 struct device *dev;
Atsushi Nemoto1e9a51d2007-01-26 00:56:54 -08001028 struct spi_master *master = NULL;
David Brownell8ae12a02006-01-08 13:34:19 -08001029
Greg Kroah-Hartman695794a2008-05-22 17:21:08 -04001030 dev = class_find_device(&spi_master_class, NULL, &bus_num,
Dave Young5ed2c832008-01-22 15:14:18 +08001031 __spi_master_match);
1032 if (dev)
1033 master = container_of(dev, struct spi_master, dev);
1034 /* reference got in class_find_device */
Atsushi Nemoto1e9a51d2007-01-26 00:56:54 -08001035 return master;
David Brownell8ae12a02006-01-08 13:34:19 -08001036}
1037EXPORT_SYMBOL_GPL(spi_busnum_to_master);
1038
1039
1040/*-------------------------------------------------------------------------*/
1041
David Brownell7d077192009-06-17 16:26:03 -07001042/* Core methods for SPI master protocol drivers. Some of the
1043 * other core methods are currently defined as inline functions.
1044 */
1045
1046/**
1047 * spi_setup - setup SPI mode and clock rate
1048 * @spi: the device whose settings are being modified
1049 * Context: can sleep, and no requests are queued to the device
1050 *
1051 * SPI protocol drivers may need to update the transfer mode if the
1052 * device doesn't work with its default. They may likewise need
1053 * to update clock rates or word sizes from initial values. This function
1054 * changes those settings, and must be called from a context that can sleep.
1055 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
1056 * effect the next time the device is selected and data is transferred to
1057 * or from it. When this function returns, the spi device is deselected.
1058 *
1059 * Note that this call will fail if the protocol driver specifies an option
1060 * that the underlying controller or its driver does not support. For
1061 * example, not all hardware supports wire transfers using nine bit words,
1062 * LSB-first wire encoding, or active-high chipselects.
1063 */
1064int spi_setup(struct spi_device *spi)
1065{
David Brownelle7db06b2009-06-17 16:26:04 -07001066 unsigned bad_bits;
David Brownell7d077192009-06-17 16:26:03 -07001067 int status;
1068
David Brownelle7db06b2009-06-17 16:26:04 -07001069 /* help drivers fail *cleanly* when they need options
1070 * that aren't supported with their current master
1071 */
1072 bad_bits = spi->mode & ~spi->master->mode_bits;
1073 if (bad_bits) {
Linus Walleijeb288a12010-10-21 21:06:44 +02001074 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
David Brownelle7db06b2009-06-17 16:26:04 -07001075 bad_bits);
1076 return -EINVAL;
1077 }
1078
David Brownell7d077192009-06-17 16:26:03 -07001079 if (!spi->bits_per_word)
1080 spi->bits_per_word = 8;
1081
1082 status = spi->master->setup(spi);
1083
1084 dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s"
1085 "%u bits/w, %u Hz max --> %d\n",
1086 (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
1087 (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
1088 (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
1089 (spi->mode & SPI_3WIRE) ? "3wire, " : "",
1090 (spi->mode & SPI_LOOP) ? "loopback, " : "",
1091 spi->bits_per_word, spi->max_speed_hz,
1092 status);
1093
1094 return status;
1095}
1096EXPORT_SYMBOL_GPL(spi_setup);
1097
Ernst Schwabcf32b712010-06-28 17:49:29 -07001098static int __spi_async(struct spi_device *spi, struct spi_message *message)
1099{
1100 struct spi_master *master = spi->master;
1101
1102 /* Half-duplex links include original MicroWire, and ones with
1103 * only one data pin like SPI_3WIRE (switches direction) or where
1104 * either MOSI or MISO is missing. They can also be caused by
1105 * software limitations.
1106 */
1107 if ((master->flags & SPI_MASTER_HALF_DUPLEX)
1108 || (spi->mode & SPI_3WIRE)) {
1109 struct spi_transfer *xfer;
1110 unsigned flags = master->flags;
1111
1112 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1113 if (xfer->rx_buf && xfer->tx_buf)
1114 return -EINVAL;
1115 if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
1116 return -EINVAL;
1117 if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
1118 return -EINVAL;
1119 }
1120 }
1121
1122 message->spi = spi;
1123 message->status = -EINPROGRESS;
1124 return master->transfer(spi, message);
1125}
1126
David Brownell568d0692009-09-22 16:46:18 -07001127/**
1128 * spi_async - asynchronous SPI transfer
1129 * @spi: device with which data will be exchanged
1130 * @message: describes the data transfers, including completion callback
1131 * Context: any (irqs may be blocked, etc)
1132 *
1133 * This call may be used in_irq and other contexts which can't sleep,
1134 * as well as from task contexts which can sleep.
1135 *
1136 * The completion callback is invoked in a context which can't sleep.
1137 * Before that invocation, the value of message->status is undefined.
1138 * When the callback is issued, message->status holds either zero (to
1139 * indicate complete success) or a negative error code. After that
1140 * callback returns, the driver which issued the transfer request may
1141 * deallocate the associated memory; it's no longer in use by any SPI
1142 * core or controller driver code.
1143 *
1144 * Note that although all messages to a spi_device are handled in
1145 * FIFO order, messages may go to different devices in other orders.
1146 * Some device might be higher priority, or have various "hard" access
1147 * time requirements, for example.
1148 *
1149 * On detection of any fault during the transfer, processing of
1150 * the entire message is aborted, and the device is deselected.
1151 * Until returning from the associated message completion callback,
1152 * no other spi_message queued to that device will be processed.
1153 * (This rule applies equally to all the synchronous transfer calls,
1154 * which are wrappers around this core asynchronous primitive.)
1155 */
1156int spi_async(struct spi_device *spi, struct spi_message *message)
1157{
1158 struct spi_master *master = spi->master;
Ernst Schwabcf32b712010-06-28 17:49:29 -07001159 int ret;
1160 unsigned long flags;
David Brownell568d0692009-09-22 16:46:18 -07001161
Ernst Schwabcf32b712010-06-28 17:49:29 -07001162 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
David Brownell568d0692009-09-22 16:46:18 -07001163
Ernst Schwabcf32b712010-06-28 17:49:29 -07001164 if (master->bus_lock_flag)
1165 ret = -EBUSY;
1166 else
1167 ret = __spi_async(spi, message);
David Brownell568d0692009-09-22 16:46:18 -07001168
Ernst Schwabcf32b712010-06-28 17:49:29 -07001169 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
1170
1171 return ret;
David Brownell568d0692009-09-22 16:46:18 -07001172}
1173EXPORT_SYMBOL_GPL(spi_async);
1174
Ernst Schwabcf32b712010-06-28 17:49:29 -07001175/**
1176 * spi_async_locked - version of spi_async with exclusive bus usage
1177 * @spi: device with which data will be exchanged
1178 * @message: describes the data transfers, including completion callback
1179 * Context: any (irqs may be blocked, etc)
1180 *
1181 * This call may be used in_irq and other contexts which can't sleep,
1182 * as well as from task contexts which can sleep.
1183 *
1184 * The completion callback is invoked in a context which can't sleep.
1185 * Before that invocation, the value of message->status is undefined.
1186 * When the callback is issued, message->status holds either zero (to
1187 * indicate complete success) or a negative error code. After that
1188 * callback returns, the driver which issued the transfer request may
1189 * deallocate the associated memory; it's no longer in use by any SPI
1190 * core or controller driver code.
1191 *
1192 * Note that although all messages to a spi_device are handled in
1193 * FIFO order, messages may go to different devices in other orders.
1194 * Some device might be higher priority, or have various "hard" access
1195 * time requirements, for example.
1196 *
1197 * On detection of any fault during the transfer, processing of
1198 * the entire message is aborted, and the device is deselected.
1199 * Until returning from the associated message completion callback,
1200 * no other spi_message queued to that device will be processed.
1201 * (This rule applies equally to all the synchronous transfer calls,
1202 * which are wrappers around this core asynchronous primitive.)
1203 */
1204int spi_async_locked(struct spi_device *spi, struct spi_message *message)
1205{
1206 struct spi_master *master = spi->master;
1207 int ret;
1208 unsigned long flags;
1209
1210 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
1211
1212 ret = __spi_async(spi, message);
1213
1214 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
1215
1216 return ret;
1217
1218}
1219EXPORT_SYMBOL_GPL(spi_async_locked);
1220
David Brownell7d077192009-06-17 16:26:03 -07001221
1222/*-------------------------------------------------------------------------*/
1223
1224/* Utility methods for SPI master protocol drivers, layered on
1225 * top of the core. Some other utility methods are defined as
1226 * inline functions.
1227 */
1228
Andrew Morton5d870c82006-01-11 11:23:49 -08001229static void spi_complete(void *arg)
1230{
1231 complete(arg);
1232}
1233
Ernst Schwabcf32b712010-06-28 17:49:29 -07001234static int __spi_sync(struct spi_device *spi, struct spi_message *message,
1235 int bus_locked)
1236{
1237 DECLARE_COMPLETION_ONSTACK(done);
1238 int status;
1239 struct spi_master *master = spi->master;
1240
1241 message->complete = spi_complete;
1242 message->context = &done;
1243
1244 if (!bus_locked)
1245 mutex_lock(&master->bus_lock_mutex);
1246
1247 status = spi_async_locked(spi, message);
1248
1249 if (!bus_locked)
1250 mutex_unlock(&master->bus_lock_mutex);
1251
1252 if (status == 0) {
1253 wait_for_completion(&done);
1254 status = message->status;
1255 }
1256 message->context = NULL;
1257 return status;
1258}
1259
David Brownell8ae12a02006-01-08 13:34:19 -08001260/**
1261 * spi_sync - blocking/synchronous SPI data transfers
1262 * @spi: device with which data will be exchanged
1263 * @message: describes the data transfers
David Brownell33e34dc2007-05-08 00:32:21 -07001264 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -08001265 *
1266 * This call may only be used from a context that may sleep. The sleep
1267 * is non-interruptible, and has no timeout. Low-overhead controller
1268 * drivers may DMA directly into and out of the message buffers.
1269 *
1270 * Note that the SPI device's chip select is active during the message,
1271 * and then is normally disabled between messages. Drivers for some
1272 * frequently-used devices may want to minimize costs of selecting a chip,
1273 * by leaving it selected in anticipation that the next message will go
1274 * to the same chip. (That may increase power usage.)
1275 *
David Brownell0c868462006-01-08 13:34:25 -08001276 * Also, the caller is guaranteeing that the memory associated with the
1277 * message will not be freed before this call returns.
1278 *
Marc Pignat9b938b72007-12-04 23:45:10 -08001279 * It returns zero on success, else a negative error code.
David Brownell8ae12a02006-01-08 13:34:19 -08001280 */
1281int spi_sync(struct spi_device *spi, struct spi_message *message)
1282{
Ernst Schwabcf32b712010-06-28 17:49:29 -07001283 return __spi_sync(spi, message, 0);
David Brownell8ae12a02006-01-08 13:34:19 -08001284}
1285EXPORT_SYMBOL_GPL(spi_sync);
1286
Ernst Schwabcf32b712010-06-28 17:49:29 -07001287/**
1288 * spi_sync_locked - version of spi_sync with exclusive bus usage
1289 * @spi: device with which data will be exchanged
1290 * @message: describes the data transfers
1291 * Context: can sleep
1292 *
1293 * This call may only be used from a context that may sleep. The sleep
1294 * is non-interruptible, and has no timeout. Low-overhead controller
1295 * drivers may DMA directly into and out of the message buffers.
1296 *
1297 * This call should be used by drivers that require exclusive access to the
Lucas De Marchi25985ed2011-03-30 22:57:33 -03001298 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
Ernst Schwabcf32b712010-06-28 17:49:29 -07001299 * be released by a spi_bus_unlock call when the exclusive access is over.
1300 *
1301 * It returns zero on success, else a negative error code.
1302 */
1303int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
1304{
1305 return __spi_sync(spi, message, 1);
1306}
1307EXPORT_SYMBOL_GPL(spi_sync_locked);
1308
1309/**
1310 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
1311 * @master: SPI bus master that should be locked for exclusive bus access
1312 * Context: can sleep
1313 *
1314 * This call may only be used from a context that may sleep. The sleep
1315 * is non-interruptible, and has no timeout.
1316 *
1317 * This call should be used by drivers that require exclusive access to the
1318 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
1319 * exclusive access is over. Data transfer must be done by spi_sync_locked
1320 * and spi_async_locked calls when the SPI bus lock is held.
1321 *
1322 * It returns zero on success, else a negative error code.
1323 */
1324int spi_bus_lock(struct spi_master *master)
1325{
1326 unsigned long flags;
1327
1328 mutex_lock(&master->bus_lock_mutex);
1329
1330 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
1331 master->bus_lock_flag = 1;
1332 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
1333
1334 /* mutex remains locked until spi_bus_unlock is called */
1335
1336 return 0;
1337}
1338EXPORT_SYMBOL_GPL(spi_bus_lock);
1339
1340/**
1341 * spi_bus_unlock - release the lock for exclusive SPI bus usage
1342 * @master: SPI bus master that was locked for exclusive bus access
1343 * Context: can sleep
1344 *
1345 * This call may only be used from a context that may sleep. The sleep
1346 * is non-interruptible, and has no timeout.
1347 *
1348 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
1349 * call.
1350 *
1351 * It returns zero on success, else a negative error code.
1352 */
1353int spi_bus_unlock(struct spi_master *master)
1354{
1355 master->bus_lock_flag = 0;
1356
1357 mutex_unlock(&master->bus_lock_mutex);
1358
1359 return 0;
1360}
1361EXPORT_SYMBOL_GPL(spi_bus_unlock);
1362
David Brownella9948b62006-04-02 10:37:40 -08001363/* portable code must never pass more than 32 bytes */
1364#define SPI_BUFSIZ max(32,SMP_CACHE_BYTES)
David Brownell8ae12a02006-01-08 13:34:19 -08001365
1366static u8 *buf;
1367
1368/**
1369 * spi_write_then_read - SPI synchronous write followed by read
1370 * @spi: device with which data will be exchanged
1371 * @txbuf: data to be written (need not be dma-safe)
1372 * @n_tx: size of txbuf, in bytes
Jiri Pirko27570492009-06-17 16:26:06 -07001373 * @rxbuf: buffer into which data will be read (need not be dma-safe)
1374 * @n_rx: size of rxbuf, in bytes
David Brownell33e34dc2007-05-08 00:32:21 -07001375 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -08001376 *
1377 * This performs a half duplex MicroWire style transaction with the
1378 * device, sending txbuf and then reading rxbuf. The return value
1379 * is zero for success, else a negative errno status code.
David Brownellb8852442006-01-08 13:34:23 -08001380 * This call may only be used from a context that may sleep.
David Brownell8ae12a02006-01-08 13:34:19 -08001381 *
David Brownell0c868462006-01-08 13:34:25 -08001382 * Parameters to this routine are always copied using a small buffer;
David Brownell33e34dc2007-05-08 00:32:21 -07001383 * portable code should never use this for more than 32 bytes.
1384 * Performance-sensitive or bulk transfer code should instead use
David Brownell0c868462006-01-08 13:34:25 -08001385 * spi_{async,sync}() calls with dma-safe buffers.
David Brownell8ae12a02006-01-08 13:34:19 -08001386 */
1387int spi_write_then_read(struct spi_device *spi,
Mark Brown0c4a1592011-05-11 00:09:30 +02001388 const void *txbuf, unsigned n_tx,
1389 void *rxbuf, unsigned n_rx)
David Brownell8ae12a02006-01-08 13:34:19 -08001390{
David Brownell068f4072007-12-04 23:45:09 -08001391 static DEFINE_MUTEX(lock);
David Brownell8ae12a02006-01-08 13:34:19 -08001392
1393 int status;
1394 struct spi_message message;
David Brownellbdff5492009-04-13 14:39:57 -07001395 struct spi_transfer x[2];
David Brownell8ae12a02006-01-08 13:34:19 -08001396 u8 *local_buf;
1397
1398 /* Use preallocated DMA-safe buffer. We can't avoid copying here,
1399 * (as a pure convenience thing), but we can keep heap costs
1400 * out of the hot path ...
1401 */
1402 if ((n_tx + n_rx) > SPI_BUFSIZ)
1403 return -EINVAL;
1404
Vitaly Wool8275c642006-01-08 13:34:28 -08001405 spi_message_init(&message);
David Brownellbdff5492009-04-13 14:39:57 -07001406 memset(x, 0, sizeof x);
1407 if (n_tx) {
1408 x[0].len = n_tx;
1409 spi_message_add_tail(&x[0], &message);
1410 }
1411 if (n_rx) {
1412 x[1].len = n_rx;
1413 spi_message_add_tail(&x[1], &message);
1414 }
Vitaly Wool8275c642006-01-08 13:34:28 -08001415
David Brownell8ae12a02006-01-08 13:34:19 -08001416 /* ... unless someone else is using the pre-allocated buffer */
David Brownell068f4072007-12-04 23:45:09 -08001417 if (!mutex_trylock(&lock)) {
David Brownell8ae12a02006-01-08 13:34:19 -08001418 local_buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
1419 if (!local_buf)
1420 return -ENOMEM;
1421 } else
1422 local_buf = buf;
1423
David Brownell8ae12a02006-01-08 13:34:19 -08001424 memcpy(local_buf, txbuf, n_tx);
David Brownellbdff5492009-04-13 14:39:57 -07001425 x[0].tx_buf = local_buf;
1426 x[1].rx_buf = local_buf + n_tx;
David Brownell8ae12a02006-01-08 13:34:19 -08001427
1428 /* do the i/o */
David Brownell8ae12a02006-01-08 13:34:19 -08001429 status = spi_sync(spi, &message);
Marc Pignat9b938b72007-12-04 23:45:10 -08001430 if (status == 0)
David Brownellbdff5492009-04-13 14:39:57 -07001431 memcpy(rxbuf, x[1].rx_buf, n_rx);
David Brownell8ae12a02006-01-08 13:34:19 -08001432
David Brownellbdff5492009-04-13 14:39:57 -07001433 if (x[0].tx_buf == buf)
David Brownell068f4072007-12-04 23:45:09 -08001434 mutex_unlock(&lock);
David Brownell8ae12a02006-01-08 13:34:19 -08001435 else
1436 kfree(local_buf);
1437
1438 return status;
1439}
1440EXPORT_SYMBOL_GPL(spi_write_then_read);
1441
1442/*-------------------------------------------------------------------------*/
1443
1444static int __init spi_init(void)
1445{
David Brownellb8852442006-01-08 13:34:23 -08001446 int status;
David Brownell8ae12a02006-01-08 13:34:19 -08001447
Christoph Lametere94b1762006-12-06 20:33:17 -08001448 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
David Brownellb8852442006-01-08 13:34:23 -08001449 if (!buf) {
1450 status = -ENOMEM;
1451 goto err0;
1452 }
1453
1454 status = bus_register(&spi_bus_type);
1455 if (status < 0)
1456 goto err1;
1457
1458 status = class_register(&spi_master_class);
1459 if (status < 0)
1460 goto err2;
David Brownell8ae12a02006-01-08 13:34:19 -08001461 return 0;
David Brownellb8852442006-01-08 13:34:23 -08001462
1463err2:
1464 bus_unregister(&spi_bus_type);
1465err1:
1466 kfree(buf);
1467 buf = NULL;
1468err0:
1469 return status;
David Brownell8ae12a02006-01-08 13:34:19 -08001470}
David Brownellb8852442006-01-08 13:34:23 -08001471
David Brownell8ae12a02006-01-08 13:34:19 -08001472/* board_info is normally registered in arch_initcall(),
1473 * but even essential drivers wait till later
David Brownellb8852442006-01-08 13:34:23 -08001474 *
1475 * REVISIT only boardinfo really needs static linking. the rest (device and
1476 * driver registration) _could_ be dynamically linked (modular) ... costs
1477 * include needing to have boardinfo data structures be much more public.
David Brownell8ae12a02006-01-08 13:34:19 -08001478 */
David Brownell673c0c02008-10-15 22:02:46 -07001479postcore_initcall(spi_init);
David Brownell8ae12a02006-01-08 13:34:19 -08001480