blob: 709c836607de23636e6c567a38833cceff752b08 [file] [log] [blame]
David Brownell8ae12a02006-01-08 13:34:19 -08001/*
2 * spi.c - SPI init/core code
3 *
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>
David Brownell8ae12a02006-01-08 13:34:19 -080031
David Brownell8ae12a02006-01-08 13:34:19 -080032static void spidev_release(struct device *dev)
33{
Hans-Peter Nilsson0ffa0282007-02-12 00:52:45 -080034 struct spi_device *spi = to_spi_device(dev);
David Brownell8ae12a02006-01-08 13:34:19 -080035
36 /* spi masters may cleanup for released devices */
37 if (spi->master->cleanup)
38 spi->master->cleanup(spi);
39
David Brownell0c868462006-01-08 13:34:25 -080040 spi_master_put(spi->master);
Roman Tereshonkov07a389f2010-04-12 09:56:35 +000041 kfree(spi);
David Brownell8ae12a02006-01-08 13:34:19 -080042}
43
44static ssize_t
45modalias_show(struct device *dev, struct device_attribute *a, char *buf)
46{
47 const struct spi_device *spi = to_spi_device(dev);
48
Kay Sievers35f74fc2009-01-06 10:44:37 -080049 return sprintf(buf, "%s\n", spi->modalias);
David Brownell8ae12a02006-01-08 13:34:19 -080050}
51
52static struct device_attribute spi_dev_attrs[] = {
53 __ATTR_RO(modalias),
54 __ATTR_NULL,
55};
56
57/* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
58 * and the sysfs version makes coldplug work too.
59 */
60
Anton Vorontsov75368bf2009-09-22 16:46:04 -070061static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
62 const struct spi_device *sdev)
63{
64 while (id->name[0]) {
65 if (!strcmp(sdev->modalias, id->name))
66 return id;
67 id++;
68 }
69 return NULL;
70}
71
72const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
73{
74 const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
75
76 return spi_match_id(sdrv->id_table, sdev);
77}
78EXPORT_SYMBOL_GPL(spi_get_device_id);
79
David Brownell8ae12a02006-01-08 13:34:19 -080080static int spi_match_device(struct device *dev, struct device_driver *drv)
81{
82 const struct spi_device *spi = to_spi_device(dev);
Anton Vorontsov75368bf2009-09-22 16:46:04 -070083 const struct spi_driver *sdrv = to_spi_driver(drv);
84
Sinan Akman2b7a32f2010-10-02 21:28:29 -060085 /* Attempt an OF style match */
86 if (of_driver_match_device(dev, drv))
87 return 1;
88
Anton Vorontsov75368bf2009-09-22 16:46:04 -070089 if (sdrv->id_table)
90 return !!spi_match_id(sdrv->id_table, spi);
David Brownell8ae12a02006-01-08 13:34:19 -080091
Kay Sievers35f74fc2009-01-06 10:44:37 -080092 return strcmp(spi->modalias, drv->name) == 0;
David Brownell8ae12a02006-01-08 13:34:19 -080093}
94
Kay Sievers7eff2e72007-08-14 15:15:12 +020095static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
David Brownell8ae12a02006-01-08 13:34:19 -080096{
97 const struct spi_device *spi = to_spi_device(dev);
98
Anton Vorontsove0626e32009-09-22 16:46:08 -070099 add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
David Brownell8ae12a02006-01-08 13:34:19 -0800100 return 0;
101}
102
103#ifdef CONFIG_PM
104
David Brownell8ae12a02006-01-08 13:34:19 -0800105static int spi_suspend(struct device *dev, pm_message_t message)
106{
David Brownell3c724262008-02-06 01:38:10 -0800107 int value = 0;
David Brownellb8852442006-01-08 13:34:23 -0800108 struct spi_driver *drv = to_spi_driver(dev->driver);
David Brownell8ae12a02006-01-08 13:34:19 -0800109
David Brownell8ae12a02006-01-08 13:34:19 -0800110 /* suspend will stop irqs and dma; no more i/o */
David Brownell3c724262008-02-06 01:38:10 -0800111 if (drv) {
112 if (drv->suspend)
113 value = drv->suspend(to_spi_device(dev), message);
114 else
115 dev_dbg(dev, "... can't suspend\n");
116 }
David Brownell8ae12a02006-01-08 13:34:19 -0800117 return value;
118}
119
120static int spi_resume(struct device *dev)
121{
David Brownell3c724262008-02-06 01:38:10 -0800122 int value = 0;
David Brownellb8852442006-01-08 13:34:23 -0800123 struct spi_driver *drv = to_spi_driver(dev->driver);
David Brownell8ae12a02006-01-08 13:34:19 -0800124
David Brownell8ae12a02006-01-08 13:34:19 -0800125 /* resume may restart the i/o queue */
David Brownell3c724262008-02-06 01:38:10 -0800126 if (drv) {
127 if (drv->resume)
128 value = drv->resume(to_spi_device(dev));
129 else
130 dev_dbg(dev, "... can't resume\n");
131 }
David Brownell8ae12a02006-01-08 13:34:19 -0800132 return value;
133}
134
135#else
136#define spi_suspend NULL
137#define spi_resume NULL
138#endif
139
140struct bus_type spi_bus_type = {
141 .name = "spi",
142 .dev_attrs = spi_dev_attrs,
143 .match = spi_match_device,
144 .uevent = spi_uevent,
145 .suspend = spi_suspend,
146 .resume = spi_resume,
147};
148EXPORT_SYMBOL_GPL(spi_bus_type);
149
David Brownellb8852442006-01-08 13:34:23 -0800150
151static int spi_drv_probe(struct device *dev)
152{
153 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
154
155 return sdrv->probe(to_spi_device(dev));
156}
157
158static int spi_drv_remove(struct device *dev)
159{
160 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
161
162 return sdrv->remove(to_spi_device(dev));
163}
164
165static void spi_drv_shutdown(struct device *dev)
166{
167 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
168
169 sdrv->shutdown(to_spi_device(dev));
170}
171
David Brownell33e34dc2007-05-08 00:32:21 -0700172/**
173 * spi_register_driver - register a SPI driver
174 * @sdrv: the driver to register
175 * Context: can sleep
176 */
David Brownellb8852442006-01-08 13:34:23 -0800177int spi_register_driver(struct spi_driver *sdrv)
178{
179 sdrv->driver.bus = &spi_bus_type;
180 if (sdrv->probe)
181 sdrv->driver.probe = spi_drv_probe;
182 if (sdrv->remove)
183 sdrv->driver.remove = spi_drv_remove;
184 if (sdrv->shutdown)
185 sdrv->driver.shutdown = spi_drv_shutdown;
186 return driver_register(&sdrv->driver);
187}
188EXPORT_SYMBOL_GPL(spi_register_driver);
189
David Brownell8ae12a02006-01-08 13:34:19 -0800190/*-------------------------------------------------------------------------*/
191
192/* SPI devices should normally not be created by SPI device drivers; that
193 * would make them board-specific. Similarly with SPI master drivers.
194 * Device registration normally goes into like arch/.../mach.../board-YYY.c
195 * with other readonly (flashable) information about mainboard devices.
196 */
197
198struct boardinfo {
199 struct list_head list;
Feng Tang2b9603a2010-08-02 15:52:15 +0800200 struct spi_board_info board_info;
David Brownell8ae12a02006-01-08 13:34:19 -0800201};
202
203static LIST_HEAD(board_list);
Feng Tang2b9603a2010-08-02 15:52:15 +0800204static LIST_HEAD(spi_master_list);
205
206/*
207 * Used to protect add/del opertion for board_info list and
208 * spi_master list, and their matching process
209 */
Matthias Kaehlcke94040822007-07-17 04:04:16 -0700210static DEFINE_MUTEX(board_lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800211
Grant Likelydc87c982008-05-15 16:50:22 -0600212/**
213 * spi_alloc_device - Allocate a new SPI device
214 * @master: Controller to which device is connected
215 * Context: can sleep
216 *
217 * Allows a driver to allocate and initialize a spi_device without
218 * registering it immediately. This allows a driver to directly
219 * fill the spi_device with device parameters before calling
220 * spi_add_device() on it.
221 *
222 * Caller is responsible to call spi_add_device() on the returned
223 * spi_device structure to add it to the SPI master. If the caller
224 * needs to discard the spi_device without adding it, then it should
225 * call spi_dev_put() on it.
226 *
227 * Returns a pointer to the new device, or NULL.
228 */
229struct spi_device *spi_alloc_device(struct spi_master *master)
230{
231 struct spi_device *spi;
232 struct device *dev = master->dev.parent;
233
234 if (!spi_master_get(master))
235 return NULL;
236
237 spi = kzalloc(sizeof *spi, GFP_KERNEL);
238 if (!spi) {
239 dev_err(dev, "cannot alloc spi_device\n");
240 spi_master_put(master);
241 return NULL;
242 }
243
244 spi->master = master;
245 spi->dev.parent = dev;
246 spi->dev.bus = &spi_bus_type;
247 spi->dev.release = spidev_release;
248 device_initialize(&spi->dev);
249 return spi;
250}
251EXPORT_SYMBOL_GPL(spi_alloc_device);
252
253/**
254 * spi_add_device - Add spi_device allocated with spi_alloc_device
255 * @spi: spi_device to register
256 *
257 * Companion function to spi_alloc_device. Devices allocated with
258 * spi_alloc_device can be added onto the spi bus with this function.
259 *
David Brownelle48880e2008-08-15 00:40:44 -0700260 * Returns 0 on success; negative errno on failure
Grant Likelydc87c982008-05-15 16:50:22 -0600261 */
262int spi_add_device(struct spi_device *spi)
263{
David Brownelle48880e2008-08-15 00:40:44 -0700264 static DEFINE_MUTEX(spi_add_lock);
Grant Likelydc87c982008-05-15 16:50:22 -0600265 struct device *dev = spi->master->dev.parent;
Roman Tereshonkov8ec130a2010-04-16 09:52:59 +0000266 struct device *d;
Grant Likelydc87c982008-05-15 16:50:22 -0600267 int status;
268
269 /* Chipselects are numbered 0..max; validate. */
270 if (spi->chip_select >= spi->master->num_chipselect) {
271 dev_err(dev, "cs%d >= max %d\n",
272 spi->chip_select,
273 spi->master->num_chipselect);
274 return -EINVAL;
275 }
276
277 /* Set the bus ID string */
Kay Sievers35f74fc2009-01-06 10:44:37 -0800278 dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
Grant Likelydc87c982008-05-15 16:50:22 -0600279 spi->chip_select);
280
David Brownelle48880e2008-08-15 00:40:44 -0700281
282 /* We need to make sure there's no other device with this
283 * chipselect **BEFORE** we call setup(), else we'll trash
284 * its configuration. Lock against concurrent add() calls.
285 */
286 mutex_lock(&spi_add_lock);
287
Roman Tereshonkov8ec130a2010-04-16 09:52:59 +0000288 d = bus_find_device_by_name(&spi_bus_type, NULL, dev_name(&spi->dev));
289 if (d != NULL) {
David Brownelle48880e2008-08-15 00:40:44 -0700290 dev_err(dev, "chipselect %d already in use\n",
291 spi->chip_select);
Roman Tereshonkov8ec130a2010-04-16 09:52:59 +0000292 put_device(d);
David Brownelle48880e2008-08-15 00:40:44 -0700293 status = -EBUSY;
294 goto done;
295 }
296
297 /* Drivers may modify this initial i/o setup, but will
298 * normally rely on the device being setup. Devices
299 * using SPI_CS_HIGH can't coexist well otherwise...
300 */
David Brownell7d077192009-06-17 16:26:03 -0700301 status = spi_setup(spi);
Grant Likelydc87c982008-05-15 16:50:22 -0600302 if (status < 0) {
Linus Walleijeb288a12010-10-21 21:06:44 +0200303 dev_err(dev, "can't setup %s, status %d\n",
304 dev_name(&spi->dev), status);
David Brownelle48880e2008-08-15 00:40:44 -0700305 goto done;
Grant Likelydc87c982008-05-15 16:50:22 -0600306 }
307
David Brownelle48880e2008-08-15 00:40:44 -0700308 /* Device may be bound to an active driver when this returns */
Grant Likelydc87c982008-05-15 16:50:22 -0600309 status = device_add(&spi->dev);
David Brownelle48880e2008-08-15 00:40:44 -0700310 if (status < 0)
Linus Walleijeb288a12010-10-21 21:06:44 +0200311 dev_err(dev, "can't add %s, status %d\n",
312 dev_name(&spi->dev), status);
David Brownelle48880e2008-08-15 00:40:44 -0700313 else
Kay Sievers35f74fc2009-01-06 10:44:37 -0800314 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
Grant Likelydc87c982008-05-15 16:50:22 -0600315
David Brownelle48880e2008-08-15 00:40:44 -0700316done:
317 mutex_unlock(&spi_add_lock);
318 return status;
Grant Likelydc87c982008-05-15 16:50:22 -0600319}
320EXPORT_SYMBOL_GPL(spi_add_device);
David Brownell8ae12a02006-01-08 13:34:19 -0800321
David Brownell33e34dc2007-05-08 00:32:21 -0700322/**
323 * spi_new_device - instantiate one new SPI device
324 * @master: Controller to which device is connected
325 * @chip: Describes the SPI device
326 * Context: can sleep
327 *
328 * On typical mainboards, this is purely internal; and it's not needed
David Brownell8ae12a02006-01-08 13:34:19 -0800329 * after board init creates the hard-wired devices. Some development
330 * platforms may not be able to use spi_register_board_info though, and
331 * this is exported so that for example a USB or parport based adapter
332 * driver could add devices (which it would learn about out-of-band).
David Brownell082c8cb2007-07-31 00:39:45 -0700333 *
334 * Returns the new device, or NULL.
David Brownell8ae12a02006-01-08 13:34:19 -0800335 */
Adrian Bunke9d5a462007-03-26 21:32:23 -0800336struct spi_device *spi_new_device(struct spi_master *master,
337 struct spi_board_info *chip)
David Brownell8ae12a02006-01-08 13:34:19 -0800338{
339 struct spi_device *proxy;
David Brownell8ae12a02006-01-08 13:34:19 -0800340 int status;
341
David Brownell082c8cb2007-07-31 00:39:45 -0700342 /* NOTE: caller did any chip->bus_num checks necessary.
343 *
344 * Also, unless we change the return value convention to use
345 * error-or-pointer (not NULL-or-pointer), troubleshootability
346 * suggests syslogged diagnostics are best here (ugh).
347 */
348
Grant Likelydc87c982008-05-15 16:50:22 -0600349 proxy = spi_alloc_device(master);
350 if (!proxy)
David Brownell8ae12a02006-01-08 13:34:19 -0800351 return NULL;
352
Grant Likely102eb972008-07-23 21:29:55 -0700353 WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
354
David Brownell8ae12a02006-01-08 13:34:19 -0800355 proxy->chip_select = chip->chip_select;
356 proxy->max_speed_hz = chip->max_speed_hz;
David Brownell980a01c2006-06-28 07:47:15 -0700357 proxy->mode = chip->mode;
David Brownell8ae12a02006-01-08 13:34:19 -0800358 proxy->irq = chip->irq;
Grant Likely102eb972008-07-23 21:29:55 -0700359 strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
David Brownell8ae12a02006-01-08 13:34:19 -0800360 proxy->dev.platform_data = (void *) chip->platform_data;
361 proxy->controller_data = chip->controller_data;
362 proxy->controller_state = NULL;
David Brownell8ae12a02006-01-08 13:34:19 -0800363
Grant Likelydc87c982008-05-15 16:50:22 -0600364 status = spi_add_device(proxy);
David Brownell8ae12a02006-01-08 13:34:19 -0800365 if (status < 0) {
Grant Likelydc87c982008-05-15 16:50:22 -0600366 spi_dev_put(proxy);
367 return NULL;
David Brownell8ae12a02006-01-08 13:34:19 -0800368 }
369
David Brownell8ae12a02006-01-08 13:34:19 -0800370 return proxy;
371}
372EXPORT_SYMBOL_GPL(spi_new_device);
373
Feng Tang2b9603a2010-08-02 15:52:15 +0800374static void spi_match_master_to_boardinfo(struct spi_master *master,
375 struct spi_board_info *bi)
376{
377 struct spi_device *dev;
378
379 if (master->bus_num != bi->bus_num)
380 return;
381
382 dev = spi_new_device(master, bi);
383 if (!dev)
384 dev_err(master->dev.parent, "can't create new device for %s\n",
385 bi->modalias);
386}
387
David Brownell33e34dc2007-05-08 00:32:21 -0700388/**
389 * spi_register_board_info - register SPI devices for a given board
390 * @info: array of chip descriptors
391 * @n: how many descriptors are provided
392 * Context: can sleep
393 *
David Brownell8ae12a02006-01-08 13:34:19 -0800394 * Board-specific early init code calls this (probably during arch_initcall)
395 * with segments of the SPI device table. Any device nodes are created later,
396 * after the relevant parent SPI controller (bus_num) is defined. We keep
397 * this table of devices forever, so that reloading a controller driver will
398 * not make Linux forget about these hard-wired devices.
399 *
400 * Other code can also call this, e.g. a particular add-on board might provide
401 * SPI devices through its expansion connector, so code initializing that board
402 * would naturally declare its SPI devices.
403 *
404 * The board info passed can safely be __initdata ... but be careful of
405 * any embedded pointers (platform_data, etc), they're copied as-is.
406 */
407int __init
408spi_register_board_info(struct spi_board_info const *info, unsigned n)
409{
Feng Tang2b9603a2010-08-02 15:52:15 +0800410 struct boardinfo *bi;
411 int i;
David Brownell8ae12a02006-01-08 13:34:19 -0800412
Feng Tang2b9603a2010-08-02 15:52:15 +0800413 bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
David Brownell8ae12a02006-01-08 13:34:19 -0800414 if (!bi)
415 return -ENOMEM;
David Brownell8ae12a02006-01-08 13:34:19 -0800416
Feng Tang2b9603a2010-08-02 15:52:15 +0800417 for (i = 0; i < n; i++, bi++, info++) {
418 struct spi_master *master;
David Brownell8ae12a02006-01-08 13:34:19 -0800419
Feng Tang2b9603a2010-08-02 15:52:15 +0800420 memcpy(&bi->board_info, info, sizeof(*info));
421 mutex_lock(&board_lock);
422 list_add_tail(&bi->list, &board_list);
423 list_for_each_entry(master, &spi_master_list, list)
424 spi_match_master_to_boardinfo(master, &bi->board_info);
425 mutex_unlock(&board_lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800426 }
Feng Tang2b9603a2010-08-02 15:52:15 +0800427
428 return 0;
David Brownell8ae12a02006-01-08 13:34:19 -0800429}
430
431/*-------------------------------------------------------------------------*/
432
Tony Jones49dce682007-10-16 01:27:48 -0700433static void spi_master_release(struct device *dev)
David Brownell8ae12a02006-01-08 13:34:19 -0800434{
435 struct spi_master *master;
436
Tony Jones49dce682007-10-16 01:27:48 -0700437 master = container_of(dev, struct spi_master, dev);
David Brownell8ae12a02006-01-08 13:34:19 -0800438 kfree(master);
439}
440
441static struct class spi_master_class = {
442 .name = "spi_master",
443 .owner = THIS_MODULE,
Tony Jones49dce682007-10-16 01:27:48 -0700444 .dev_release = spi_master_release,
David Brownell8ae12a02006-01-08 13:34:19 -0800445};
446
447
448/**
449 * spi_alloc_master - allocate SPI master controller
450 * @dev: the controller, possibly using the platform_bus
David Brownell33e34dc2007-05-08 00:32:21 -0700451 * @size: how much zeroed driver-private data to allocate; the pointer to this
Tony Jones49dce682007-10-16 01:27:48 -0700452 * memory is in the driver_data field of the returned device,
David Brownell0c868462006-01-08 13:34:25 -0800453 * accessible with spi_master_get_devdata().
David Brownell33e34dc2007-05-08 00:32:21 -0700454 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800455 *
456 * This call is used only by SPI master controller drivers, which are the
457 * only ones directly touching chip registers. It's how they allocate
dmitry pervushinba1a0512006-05-20 15:00:14 -0700458 * an spi_master structure, prior to calling spi_register_master().
David Brownell8ae12a02006-01-08 13:34:19 -0800459 *
460 * This must be called from context that can sleep. It returns the SPI
461 * master structure on success, else NULL.
462 *
463 * The caller is responsible for assigning the bus number and initializing
dmitry pervushinba1a0512006-05-20 15:00:14 -0700464 * the master's methods before calling spi_register_master(); and (after errors
David Brownell0c868462006-01-08 13:34:25 -0800465 * adding the device) calling spi_master_put() to prevent a memory leak.
David Brownell8ae12a02006-01-08 13:34:19 -0800466 */
Adrian Bunke9d5a462007-03-26 21:32:23 -0800467struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
David Brownell8ae12a02006-01-08 13:34:19 -0800468{
469 struct spi_master *master;
470
David Brownell0c868462006-01-08 13:34:25 -0800471 if (!dev)
472 return NULL;
473
Christoph Lametere94b1762006-12-06 20:33:17 -0800474 master = kzalloc(size + sizeof *master, GFP_KERNEL);
David Brownell8ae12a02006-01-08 13:34:19 -0800475 if (!master)
476 return NULL;
477
Tony Jones49dce682007-10-16 01:27:48 -0700478 device_initialize(&master->dev);
479 master->dev.class = &spi_master_class;
480 master->dev.parent = get_device(dev);
David Brownell0c868462006-01-08 13:34:25 -0800481 spi_master_set_devdata(master, &master[1]);
David Brownell8ae12a02006-01-08 13:34:19 -0800482
483 return master;
484}
485EXPORT_SYMBOL_GPL(spi_alloc_master);
486
487/**
488 * spi_register_master - register SPI master controller
489 * @master: initialized master, originally from spi_alloc_master()
David Brownell33e34dc2007-05-08 00:32:21 -0700490 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800491 *
492 * SPI master controllers connect to their drivers using some non-SPI bus,
493 * such as the platform bus. The final stage of probe() in that code
494 * includes calling spi_register_master() to hook up to this SPI bus glue.
495 *
496 * SPI controllers use board specific (often SOC specific) bus numbers,
497 * and board-specific addressing for SPI devices combines those numbers
498 * with chip select numbers. Since SPI does not directly support dynamic
499 * device identification, boards need configuration tables telling which
500 * chip is at which address.
501 *
502 * This must be called from context that can sleep. It returns zero on
503 * success, else a negative error code (dropping the master's refcount).
David Brownell0c868462006-01-08 13:34:25 -0800504 * After a successful return, the caller is responsible for calling
505 * spi_unregister_master().
David Brownell8ae12a02006-01-08 13:34:19 -0800506 */
Adrian Bunke9d5a462007-03-26 21:32:23 -0800507int spi_register_master(struct spi_master *master)
David Brownell8ae12a02006-01-08 13:34:19 -0800508{
David Brownelle44a45a2007-06-03 13:50:40 -0700509 static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
Tony Jones49dce682007-10-16 01:27:48 -0700510 struct device *dev = master->dev.parent;
Feng Tang2b9603a2010-08-02 15:52:15 +0800511 struct boardinfo *bi;
David Brownell8ae12a02006-01-08 13:34:19 -0800512 int status = -ENODEV;
513 int dynamic = 0;
514
David Brownell0c868462006-01-08 13:34:25 -0800515 if (!dev)
516 return -ENODEV;
517
David Brownell082c8cb2007-07-31 00:39:45 -0700518 /* even if it's just one always-selected device, there must
519 * be at least one chipselect
520 */
521 if (master->num_chipselect == 0)
522 return -EINVAL;
523
David Brownell8ae12a02006-01-08 13:34:19 -0800524 /* convention: dynamically assigned bus IDs count down from the max */
David Brownella020ed72006-04-03 15:49:04 -0700525 if (master->bus_num < 0) {
David Brownell082c8cb2007-07-31 00:39:45 -0700526 /* FIXME switch to an IDR based scheme, something like
527 * I2C now uses, so we can't run out of "dynamic" IDs
528 */
David Brownell8ae12a02006-01-08 13:34:19 -0800529 master->bus_num = atomic_dec_return(&dyn_bus_id);
David Brownellb8852442006-01-08 13:34:23 -0800530 dynamic = 1;
David Brownell8ae12a02006-01-08 13:34:19 -0800531 }
532
Ernst Schwabcf32b712010-06-28 17:49:29 -0700533 spin_lock_init(&master->bus_lock_spinlock);
534 mutex_init(&master->bus_lock_mutex);
535 master->bus_lock_flag = 0;
536
David Brownell8ae12a02006-01-08 13:34:19 -0800537 /* register the device, then userspace will see it.
538 * registration fails if the bus ID is in use.
539 */
Kay Sievers35f74fc2009-01-06 10:44:37 -0800540 dev_set_name(&master->dev, "spi%u", master->bus_num);
Tony Jones49dce682007-10-16 01:27:48 -0700541 status = device_add(&master->dev);
David Brownellb8852442006-01-08 13:34:23 -0800542 if (status < 0)
David Brownell8ae12a02006-01-08 13:34:19 -0800543 goto done;
Kay Sievers35f74fc2009-01-06 10:44:37 -0800544 dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
David Brownell8ae12a02006-01-08 13:34:19 -0800545 dynamic ? " (dynamic)" : "");
546
Feng Tang2b9603a2010-08-02 15:52:15 +0800547 mutex_lock(&board_lock);
548 list_add_tail(&master->list, &spi_master_list);
549 list_for_each_entry(bi, &board_list, list)
550 spi_match_master_to_boardinfo(master, &bi->board_info);
551 mutex_unlock(&board_lock);
552
David Brownell8ae12a02006-01-08 13:34:19 -0800553 status = 0;
Anatolij Gustschin12b15e82010-07-27 22:35:58 +0200554
555 /* Register devices from the device tree */
556 of_register_spi_devices(master);
David Brownell8ae12a02006-01-08 13:34:19 -0800557done:
558 return status;
559}
560EXPORT_SYMBOL_GPL(spi_register_master);
561
562
David Lamparter34860082010-08-30 23:54:17 +0200563static int __unregister(struct device *dev, void *null)
David Brownell8ae12a02006-01-08 13:34:19 -0800564{
David Lamparter34860082010-08-30 23:54:17 +0200565 spi_unregister_device(to_spi_device(dev));
David Brownell8ae12a02006-01-08 13:34:19 -0800566 return 0;
567}
568
569/**
570 * spi_unregister_master - unregister SPI master controller
571 * @master: the master being unregistered
David Brownell33e34dc2007-05-08 00:32:21 -0700572 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800573 *
574 * This call is used only by SPI master controller drivers, which are the
575 * only ones directly touching chip registers.
576 *
577 * This must be called from context that can sleep.
578 */
579void spi_unregister_master(struct spi_master *master)
580{
Jeff Garzik89fc9a12006-12-06 20:35:35 -0800581 int dummy;
582
Feng Tang2b9603a2010-08-02 15:52:15 +0800583 mutex_lock(&board_lock);
584 list_del(&master->list);
585 mutex_unlock(&board_lock);
586
587 dummy = device_for_each_child(master->dev.parent, &master->dev,
588 __unregister);
Tony Jones49dce682007-10-16 01:27:48 -0700589 device_unregister(&master->dev);
David Brownell8ae12a02006-01-08 13:34:19 -0800590}
591EXPORT_SYMBOL_GPL(spi_unregister_master);
592
Dave Young5ed2c832008-01-22 15:14:18 +0800593static int __spi_master_match(struct device *dev, void *data)
594{
595 struct spi_master *m;
596 u16 *bus_num = data;
597
598 m = container_of(dev, struct spi_master, dev);
599 return m->bus_num == *bus_num;
600}
601
David Brownell8ae12a02006-01-08 13:34:19 -0800602/**
603 * spi_busnum_to_master - look up master associated with bus_num
604 * @bus_num: the master's bus number
David Brownell33e34dc2007-05-08 00:32:21 -0700605 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800606 *
607 * This call may be used with devices that are registered after
608 * arch init time. It returns a refcounted pointer to the relevant
609 * spi_master (which the caller must release), or NULL if there is
610 * no such master registered.
611 */
612struct spi_master *spi_busnum_to_master(u16 bus_num)
613{
Tony Jones49dce682007-10-16 01:27:48 -0700614 struct device *dev;
Atsushi Nemoto1e9a51d2007-01-26 00:56:54 -0800615 struct spi_master *master = NULL;
David Brownell8ae12a02006-01-08 13:34:19 -0800616
Greg Kroah-Hartman695794a2008-05-22 17:21:08 -0400617 dev = class_find_device(&spi_master_class, NULL, &bus_num,
Dave Young5ed2c832008-01-22 15:14:18 +0800618 __spi_master_match);
619 if (dev)
620 master = container_of(dev, struct spi_master, dev);
621 /* reference got in class_find_device */
Atsushi Nemoto1e9a51d2007-01-26 00:56:54 -0800622 return master;
David Brownell8ae12a02006-01-08 13:34:19 -0800623}
624EXPORT_SYMBOL_GPL(spi_busnum_to_master);
625
626
627/*-------------------------------------------------------------------------*/
628
David Brownell7d077192009-06-17 16:26:03 -0700629/* Core methods for SPI master protocol drivers. Some of the
630 * other core methods are currently defined as inline functions.
631 */
632
633/**
634 * spi_setup - setup SPI mode and clock rate
635 * @spi: the device whose settings are being modified
636 * Context: can sleep, and no requests are queued to the device
637 *
638 * SPI protocol drivers may need to update the transfer mode if the
639 * device doesn't work with its default. They may likewise need
640 * to update clock rates or word sizes from initial values. This function
641 * changes those settings, and must be called from a context that can sleep.
642 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
643 * effect the next time the device is selected and data is transferred to
644 * or from it. When this function returns, the spi device is deselected.
645 *
646 * Note that this call will fail if the protocol driver specifies an option
647 * that the underlying controller or its driver does not support. For
648 * example, not all hardware supports wire transfers using nine bit words,
649 * LSB-first wire encoding, or active-high chipselects.
650 */
651int spi_setup(struct spi_device *spi)
652{
David Brownelle7db06b2009-06-17 16:26:04 -0700653 unsigned bad_bits;
David Brownell7d077192009-06-17 16:26:03 -0700654 int status;
655
David Brownelle7db06b2009-06-17 16:26:04 -0700656 /* help drivers fail *cleanly* when they need options
657 * that aren't supported with their current master
658 */
659 bad_bits = spi->mode & ~spi->master->mode_bits;
660 if (bad_bits) {
Linus Walleijeb288a12010-10-21 21:06:44 +0200661 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
David Brownelle7db06b2009-06-17 16:26:04 -0700662 bad_bits);
663 return -EINVAL;
664 }
665
David Brownell7d077192009-06-17 16:26:03 -0700666 if (!spi->bits_per_word)
667 spi->bits_per_word = 8;
668
669 status = spi->master->setup(spi);
670
671 dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s"
672 "%u bits/w, %u Hz max --> %d\n",
673 (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
674 (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
675 (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
676 (spi->mode & SPI_3WIRE) ? "3wire, " : "",
677 (spi->mode & SPI_LOOP) ? "loopback, " : "",
678 spi->bits_per_word, spi->max_speed_hz,
679 status);
680
681 return status;
682}
683EXPORT_SYMBOL_GPL(spi_setup);
684
Ernst Schwabcf32b712010-06-28 17:49:29 -0700685static int __spi_async(struct spi_device *spi, struct spi_message *message)
686{
687 struct spi_master *master = spi->master;
688
689 /* Half-duplex links include original MicroWire, and ones with
690 * only one data pin like SPI_3WIRE (switches direction) or where
691 * either MOSI or MISO is missing. They can also be caused by
692 * software limitations.
693 */
694 if ((master->flags & SPI_MASTER_HALF_DUPLEX)
695 || (spi->mode & SPI_3WIRE)) {
696 struct spi_transfer *xfer;
697 unsigned flags = master->flags;
698
699 list_for_each_entry(xfer, &message->transfers, transfer_list) {
700 if (xfer->rx_buf && xfer->tx_buf)
701 return -EINVAL;
702 if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
703 return -EINVAL;
704 if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
705 return -EINVAL;
706 }
707 }
708
709 message->spi = spi;
710 message->status = -EINPROGRESS;
711 return master->transfer(spi, message);
712}
713
David Brownell568d0692009-09-22 16:46:18 -0700714/**
715 * spi_async - asynchronous SPI transfer
716 * @spi: device with which data will be exchanged
717 * @message: describes the data transfers, including completion callback
718 * Context: any (irqs may be blocked, etc)
719 *
720 * This call may be used in_irq and other contexts which can't sleep,
721 * as well as from task contexts which can sleep.
722 *
723 * The completion callback is invoked in a context which can't sleep.
724 * Before that invocation, the value of message->status is undefined.
725 * When the callback is issued, message->status holds either zero (to
726 * indicate complete success) or a negative error code. After that
727 * callback returns, the driver which issued the transfer request may
728 * deallocate the associated memory; it's no longer in use by any SPI
729 * core or controller driver code.
730 *
731 * Note that although all messages to a spi_device are handled in
732 * FIFO order, messages may go to different devices in other orders.
733 * Some device might be higher priority, or have various "hard" access
734 * time requirements, for example.
735 *
736 * On detection of any fault during the transfer, processing of
737 * the entire message is aborted, and the device is deselected.
738 * Until returning from the associated message completion callback,
739 * no other spi_message queued to that device will be processed.
740 * (This rule applies equally to all the synchronous transfer calls,
741 * which are wrappers around this core asynchronous primitive.)
742 */
743int spi_async(struct spi_device *spi, struct spi_message *message)
744{
745 struct spi_master *master = spi->master;
Ernst Schwabcf32b712010-06-28 17:49:29 -0700746 int ret;
747 unsigned long flags;
David Brownell568d0692009-09-22 16:46:18 -0700748
Ernst Schwabcf32b712010-06-28 17:49:29 -0700749 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
David Brownell568d0692009-09-22 16:46:18 -0700750
Ernst Schwabcf32b712010-06-28 17:49:29 -0700751 if (master->bus_lock_flag)
752 ret = -EBUSY;
753 else
754 ret = __spi_async(spi, message);
David Brownell568d0692009-09-22 16:46:18 -0700755
Ernst Schwabcf32b712010-06-28 17:49:29 -0700756 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
757
758 return ret;
David Brownell568d0692009-09-22 16:46:18 -0700759}
760EXPORT_SYMBOL_GPL(spi_async);
761
Ernst Schwabcf32b712010-06-28 17:49:29 -0700762/**
763 * spi_async_locked - version of spi_async with exclusive bus usage
764 * @spi: device with which data will be exchanged
765 * @message: describes the data transfers, including completion callback
766 * Context: any (irqs may be blocked, etc)
767 *
768 * This call may be used in_irq and other contexts which can't sleep,
769 * as well as from task contexts which can sleep.
770 *
771 * The completion callback is invoked in a context which can't sleep.
772 * Before that invocation, the value of message->status is undefined.
773 * When the callback is issued, message->status holds either zero (to
774 * indicate complete success) or a negative error code. After that
775 * callback returns, the driver which issued the transfer request may
776 * deallocate the associated memory; it's no longer in use by any SPI
777 * core or controller driver code.
778 *
779 * Note that although all messages to a spi_device are handled in
780 * FIFO order, messages may go to different devices in other orders.
781 * Some device might be higher priority, or have various "hard" access
782 * time requirements, for example.
783 *
784 * On detection of any fault during the transfer, processing of
785 * the entire message is aborted, and the device is deselected.
786 * Until returning from the associated message completion callback,
787 * no other spi_message queued to that device will be processed.
788 * (This rule applies equally to all the synchronous transfer calls,
789 * which are wrappers around this core asynchronous primitive.)
790 */
791int spi_async_locked(struct spi_device *spi, struct spi_message *message)
792{
793 struct spi_master *master = spi->master;
794 int ret;
795 unsigned long flags;
796
797 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
798
799 ret = __spi_async(spi, message);
800
801 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
802
803 return ret;
804
805}
806EXPORT_SYMBOL_GPL(spi_async_locked);
807
David Brownell7d077192009-06-17 16:26:03 -0700808
809/*-------------------------------------------------------------------------*/
810
811/* Utility methods for SPI master protocol drivers, layered on
812 * top of the core. Some other utility methods are defined as
813 * inline functions.
814 */
815
Andrew Morton5d870c82006-01-11 11:23:49 -0800816static void spi_complete(void *arg)
817{
818 complete(arg);
819}
820
Ernst Schwabcf32b712010-06-28 17:49:29 -0700821static int __spi_sync(struct spi_device *spi, struct spi_message *message,
822 int bus_locked)
823{
824 DECLARE_COMPLETION_ONSTACK(done);
825 int status;
826 struct spi_master *master = spi->master;
827
828 message->complete = spi_complete;
829 message->context = &done;
830
831 if (!bus_locked)
832 mutex_lock(&master->bus_lock_mutex);
833
834 status = spi_async_locked(spi, message);
835
836 if (!bus_locked)
837 mutex_unlock(&master->bus_lock_mutex);
838
839 if (status == 0) {
840 wait_for_completion(&done);
841 status = message->status;
842 }
843 message->context = NULL;
844 return status;
845}
846
David Brownell8ae12a02006-01-08 13:34:19 -0800847/**
848 * spi_sync - blocking/synchronous SPI data transfers
849 * @spi: device with which data will be exchanged
850 * @message: describes the data transfers
David Brownell33e34dc2007-05-08 00:32:21 -0700851 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800852 *
853 * This call may only be used from a context that may sleep. The sleep
854 * is non-interruptible, and has no timeout. Low-overhead controller
855 * drivers may DMA directly into and out of the message buffers.
856 *
857 * Note that the SPI device's chip select is active during the message,
858 * and then is normally disabled between messages. Drivers for some
859 * frequently-used devices may want to minimize costs of selecting a chip,
860 * by leaving it selected in anticipation that the next message will go
861 * to the same chip. (That may increase power usage.)
862 *
David Brownell0c868462006-01-08 13:34:25 -0800863 * Also, the caller is guaranteeing that the memory associated with the
864 * message will not be freed before this call returns.
865 *
Marc Pignat9b938b72007-12-04 23:45:10 -0800866 * It returns zero on success, else a negative error code.
David Brownell8ae12a02006-01-08 13:34:19 -0800867 */
868int spi_sync(struct spi_device *spi, struct spi_message *message)
869{
Ernst Schwabcf32b712010-06-28 17:49:29 -0700870 return __spi_sync(spi, message, 0);
David Brownell8ae12a02006-01-08 13:34:19 -0800871}
872EXPORT_SYMBOL_GPL(spi_sync);
873
Ernst Schwabcf32b712010-06-28 17:49:29 -0700874/**
875 * spi_sync_locked - version of spi_sync with exclusive bus usage
876 * @spi: device with which data will be exchanged
877 * @message: describes the data transfers
878 * Context: can sleep
879 *
880 * This call may only be used from a context that may sleep. The sleep
881 * is non-interruptible, and has no timeout. Low-overhead controller
882 * drivers may DMA directly into and out of the message buffers.
883 *
884 * This call should be used by drivers that require exclusive access to the
885 * SPI bus. It has to be preceeded by a spi_bus_lock call. The SPI bus must
886 * be released by a spi_bus_unlock call when the exclusive access is over.
887 *
888 * It returns zero on success, else a negative error code.
889 */
890int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
891{
892 return __spi_sync(spi, message, 1);
893}
894EXPORT_SYMBOL_GPL(spi_sync_locked);
895
896/**
897 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
898 * @master: SPI bus master that should be locked for exclusive bus access
899 * Context: can sleep
900 *
901 * This call may only be used from a context that may sleep. The sleep
902 * is non-interruptible, and has no timeout.
903 *
904 * This call should be used by drivers that require exclusive access to the
905 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
906 * exclusive access is over. Data transfer must be done by spi_sync_locked
907 * and spi_async_locked calls when the SPI bus lock is held.
908 *
909 * It returns zero on success, else a negative error code.
910 */
911int spi_bus_lock(struct spi_master *master)
912{
913 unsigned long flags;
914
915 mutex_lock(&master->bus_lock_mutex);
916
917 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
918 master->bus_lock_flag = 1;
919 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
920
921 /* mutex remains locked until spi_bus_unlock is called */
922
923 return 0;
924}
925EXPORT_SYMBOL_GPL(spi_bus_lock);
926
927/**
928 * spi_bus_unlock - release the lock for exclusive SPI bus usage
929 * @master: SPI bus master that was locked for exclusive bus access
930 * Context: can sleep
931 *
932 * This call may only be used from a context that may sleep. The sleep
933 * is non-interruptible, and has no timeout.
934 *
935 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
936 * call.
937 *
938 * It returns zero on success, else a negative error code.
939 */
940int spi_bus_unlock(struct spi_master *master)
941{
942 master->bus_lock_flag = 0;
943
944 mutex_unlock(&master->bus_lock_mutex);
945
946 return 0;
947}
948EXPORT_SYMBOL_GPL(spi_bus_unlock);
949
David Brownella9948b62006-04-02 10:37:40 -0800950/* portable code must never pass more than 32 bytes */
951#define SPI_BUFSIZ max(32,SMP_CACHE_BYTES)
David Brownell8ae12a02006-01-08 13:34:19 -0800952
953static u8 *buf;
954
955/**
956 * spi_write_then_read - SPI synchronous write followed by read
957 * @spi: device with which data will be exchanged
958 * @txbuf: data to be written (need not be dma-safe)
959 * @n_tx: size of txbuf, in bytes
Jiri Pirko27570492009-06-17 16:26:06 -0700960 * @rxbuf: buffer into which data will be read (need not be dma-safe)
961 * @n_rx: size of rxbuf, in bytes
David Brownell33e34dc2007-05-08 00:32:21 -0700962 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800963 *
964 * This performs a half duplex MicroWire style transaction with the
965 * device, sending txbuf and then reading rxbuf. The return value
966 * is zero for success, else a negative errno status code.
David Brownellb8852442006-01-08 13:34:23 -0800967 * This call may only be used from a context that may sleep.
David Brownell8ae12a02006-01-08 13:34:19 -0800968 *
David Brownell0c868462006-01-08 13:34:25 -0800969 * Parameters to this routine are always copied using a small buffer;
David Brownell33e34dc2007-05-08 00:32:21 -0700970 * portable code should never use this for more than 32 bytes.
971 * Performance-sensitive or bulk transfer code should instead use
David Brownell0c868462006-01-08 13:34:25 -0800972 * spi_{async,sync}() calls with dma-safe buffers.
David Brownell8ae12a02006-01-08 13:34:19 -0800973 */
974int spi_write_then_read(struct spi_device *spi,
975 const u8 *txbuf, unsigned n_tx,
976 u8 *rxbuf, unsigned n_rx)
977{
David Brownell068f4072007-12-04 23:45:09 -0800978 static DEFINE_MUTEX(lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800979
980 int status;
981 struct spi_message message;
David Brownellbdff5492009-04-13 14:39:57 -0700982 struct spi_transfer x[2];
David Brownell8ae12a02006-01-08 13:34:19 -0800983 u8 *local_buf;
984
985 /* Use preallocated DMA-safe buffer. We can't avoid copying here,
986 * (as a pure convenience thing), but we can keep heap costs
987 * out of the hot path ...
988 */
989 if ((n_tx + n_rx) > SPI_BUFSIZ)
990 return -EINVAL;
991
Vitaly Wool8275c642006-01-08 13:34:28 -0800992 spi_message_init(&message);
David Brownellbdff5492009-04-13 14:39:57 -0700993 memset(x, 0, sizeof x);
994 if (n_tx) {
995 x[0].len = n_tx;
996 spi_message_add_tail(&x[0], &message);
997 }
998 if (n_rx) {
999 x[1].len = n_rx;
1000 spi_message_add_tail(&x[1], &message);
1001 }
Vitaly Wool8275c642006-01-08 13:34:28 -08001002
David Brownell8ae12a02006-01-08 13:34:19 -08001003 /* ... unless someone else is using the pre-allocated buffer */
David Brownell068f4072007-12-04 23:45:09 -08001004 if (!mutex_trylock(&lock)) {
David Brownell8ae12a02006-01-08 13:34:19 -08001005 local_buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
1006 if (!local_buf)
1007 return -ENOMEM;
1008 } else
1009 local_buf = buf;
1010
David Brownell8ae12a02006-01-08 13:34:19 -08001011 memcpy(local_buf, txbuf, n_tx);
David Brownellbdff5492009-04-13 14:39:57 -07001012 x[0].tx_buf = local_buf;
1013 x[1].rx_buf = local_buf + n_tx;
David Brownell8ae12a02006-01-08 13:34:19 -08001014
1015 /* do the i/o */
David Brownell8ae12a02006-01-08 13:34:19 -08001016 status = spi_sync(spi, &message);
Marc Pignat9b938b72007-12-04 23:45:10 -08001017 if (status == 0)
David Brownellbdff5492009-04-13 14:39:57 -07001018 memcpy(rxbuf, x[1].rx_buf, n_rx);
David Brownell8ae12a02006-01-08 13:34:19 -08001019
David Brownellbdff5492009-04-13 14:39:57 -07001020 if (x[0].tx_buf == buf)
David Brownell068f4072007-12-04 23:45:09 -08001021 mutex_unlock(&lock);
David Brownell8ae12a02006-01-08 13:34:19 -08001022 else
1023 kfree(local_buf);
1024
1025 return status;
1026}
1027EXPORT_SYMBOL_GPL(spi_write_then_read);
1028
1029/*-------------------------------------------------------------------------*/
1030
1031static int __init spi_init(void)
1032{
David Brownellb8852442006-01-08 13:34:23 -08001033 int status;
David Brownell8ae12a02006-01-08 13:34:19 -08001034
Christoph Lametere94b1762006-12-06 20:33:17 -08001035 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
David Brownellb8852442006-01-08 13:34:23 -08001036 if (!buf) {
1037 status = -ENOMEM;
1038 goto err0;
1039 }
1040
1041 status = bus_register(&spi_bus_type);
1042 if (status < 0)
1043 goto err1;
1044
1045 status = class_register(&spi_master_class);
1046 if (status < 0)
1047 goto err2;
David Brownell8ae12a02006-01-08 13:34:19 -08001048 return 0;
David Brownellb8852442006-01-08 13:34:23 -08001049
1050err2:
1051 bus_unregister(&spi_bus_type);
1052err1:
1053 kfree(buf);
1054 buf = NULL;
1055err0:
1056 return status;
David Brownell8ae12a02006-01-08 13:34:19 -08001057}
David Brownellb8852442006-01-08 13:34:23 -08001058
David Brownell8ae12a02006-01-08 13:34:19 -08001059/* board_info is normally registered in arch_initcall(),
1060 * but even essential drivers wait till later
David Brownellb8852442006-01-08 13:34:23 -08001061 *
1062 * REVISIT only boardinfo really needs static linking. the rest (device and
1063 * driver registration) _could_ be dynamically linked (modular) ... costs
1064 * include needing to have boardinfo data structures be much more public.
David Brownell8ae12a02006-01-08 13:34:19 -08001065 */
David Brownell673c0c02008-10-15 22:02:46 -07001066postcore_initcall(spi_init);
David Brownell8ae12a02006-01-08 13:34:19 -08001067