blob: fdde7061ef586695891f956cfb929f5f5e08dfdd [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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090026#include <linux/slab.h>
Anton Vorontsove0626e32009-09-22 16:46:08 -070027#include <linux/mod_devicetable.h>
David Brownell8ae12a02006-01-08 13:34:19 -080028#include <linux/spi/spi.h>
29
30
David Brownellb8852442006-01-08 13:34:23 -080031/* SPI bustype and spi_master class are registered after board init code
32 * provides the SPI device tables, ensuring that both are present by the
33 * time controller driver registration causes spi_devices to "enumerate".
David Brownell8ae12a02006-01-08 13:34:19 -080034 */
35static void spidev_release(struct device *dev)
36{
Hans-Peter Nilsson0ffa0282007-02-12 00:52:45 -080037 struct spi_device *spi = to_spi_device(dev);
David Brownell8ae12a02006-01-08 13:34:19 -080038
39 /* spi masters may cleanup for released devices */
40 if (spi->master->cleanup)
41 spi->master->cleanup(spi);
42
David Brownell0c868462006-01-08 13:34:25 -080043 spi_master_put(spi->master);
Roman Tereshonkov07a389f2010-04-12 09:56:35 +000044 kfree(spi);
David Brownell8ae12a02006-01-08 13:34:19 -080045}
46
47static ssize_t
48modalias_show(struct device *dev, struct device_attribute *a, char *buf)
49{
50 const struct spi_device *spi = to_spi_device(dev);
51
Kay Sievers35f74fc2009-01-06 10:44:37 -080052 return sprintf(buf, "%s\n", spi->modalias);
David Brownell8ae12a02006-01-08 13:34:19 -080053}
54
55static struct device_attribute spi_dev_attrs[] = {
56 __ATTR_RO(modalias),
57 __ATTR_NULL,
58};
59
60/* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
61 * and the sysfs version makes coldplug work too.
62 */
63
Anton Vorontsov75368bf2009-09-22 16:46:04 -070064static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
65 const struct spi_device *sdev)
66{
67 while (id->name[0]) {
68 if (!strcmp(sdev->modalias, id->name))
69 return id;
70 id++;
71 }
72 return NULL;
73}
74
75const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
76{
77 const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
78
79 return spi_match_id(sdrv->id_table, sdev);
80}
81EXPORT_SYMBOL_GPL(spi_get_device_id);
82
David Brownell8ae12a02006-01-08 13:34:19 -080083static int spi_match_device(struct device *dev, struct device_driver *drv)
84{
85 const struct spi_device *spi = to_spi_device(dev);
Anton Vorontsov75368bf2009-09-22 16:46:04 -070086 const struct spi_driver *sdrv = to_spi_driver(drv);
87
88 if (sdrv->id_table)
89 return !!spi_match_id(sdrv->id_table, spi);
David Brownell8ae12a02006-01-08 13:34:19 -080090
Kay Sievers35f74fc2009-01-06 10:44:37 -080091 return strcmp(spi->modalias, drv->name) == 0;
David Brownell8ae12a02006-01-08 13:34:19 -080092}
93
Kay Sievers7eff2e72007-08-14 15:15:12 +020094static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
David Brownell8ae12a02006-01-08 13:34:19 -080095{
96 const struct spi_device *spi = to_spi_device(dev);
97
Anton Vorontsove0626e32009-09-22 16:46:08 -070098 add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
David Brownell8ae12a02006-01-08 13:34:19 -080099 return 0;
100}
101
102#ifdef CONFIG_PM
103
David Brownell8ae12a02006-01-08 13:34:19 -0800104static int spi_suspend(struct device *dev, pm_message_t message)
105{
David Brownell3c724262008-02-06 01:38:10 -0800106 int value = 0;
David Brownellb8852442006-01-08 13:34:23 -0800107 struct spi_driver *drv = to_spi_driver(dev->driver);
David Brownell8ae12a02006-01-08 13:34:19 -0800108
David Brownell8ae12a02006-01-08 13:34:19 -0800109 /* suspend will stop irqs and dma; no more i/o */
David Brownell3c724262008-02-06 01:38:10 -0800110 if (drv) {
111 if (drv->suspend)
112 value = drv->suspend(to_spi_device(dev), message);
113 else
114 dev_dbg(dev, "... can't suspend\n");
115 }
David Brownell8ae12a02006-01-08 13:34:19 -0800116 return value;
117}
118
119static int spi_resume(struct device *dev)
120{
David Brownell3c724262008-02-06 01:38:10 -0800121 int value = 0;
David Brownellb8852442006-01-08 13:34:23 -0800122 struct spi_driver *drv = to_spi_driver(dev->driver);
David Brownell8ae12a02006-01-08 13:34:19 -0800123
David Brownell8ae12a02006-01-08 13:34:19 -0800124 /* resume may restart the i/o queue */
David Brownell3c724262008-02-06 01:38:10 -0800125 if (drv) {
126 if (drv->resume)
127 value = drv->resume(to_spi_device(dev));
128 else
129 dev_dbg(dev, "... can't resume\n");
130 }
David Brownell8ae12a02006-01-08 13:34:19 -0800131 return value;
132}
133
134#else
135#define spi_suspend NULL
136#define spi_resume NULL
137#endif
138
139struct bus_type spi_bus_type = {
140 .name = "spi",
141 .dev_attrs = spi_dev_attrs,
142 .match = spi_match_device,
143 .uevent = spi_uevent,
144 .suspend = spi_suspend,
145 .resume = spi_resume,
146};
147EXPORT_SYMBOL_GPL(spi_bus_type);
148
David Brownellb8852442006-01-08 13:34:23 -0800149
150static int spi_drv_probe(struct device *dev)
151{
152 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
153
154 return sdrv->probe(to_spi_device(dev));
155}
156
157static int spi_drv_remove(struct device *dev)
158{
159 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
160
161 return sdrv->remove(to_spi_device(dev));
162}
163
164static void spi_drv_shutdown(struct device *dev)
165{
166 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
167
168 sdrv->shutdown(to_spi_device(dev));
169}
170
David Brownell33e34dc2007-05-08 00:32:21 -0700171/**
172 * spi_register_driver - register a SPI driver
173 * @sdrv: the driver to register
174 * Context: can sleep
175 */
David Brownellb8852442006-01-08 13:34:23 -0800176int spi_register_driver(struct spi_driver *sdrv)
177{
178 sdrv->driver.bus = &spi_bus_type;
179 if (sdrv->probe)
180 sdrv->driver.probe = spi_drv_probe;
181 if (sdrv->remove)
182 sdrv->driver.remove = spi_drv_remove;
183 if (sdrv->shutdown)
184 sdrv->driver.shutdown = spi_drv_shutdown;
185 return driver_register(&sdrv->driver);
186}
187EXPORT_SYMBOL_GPL(spi_register_driver);
188
David Brownell8ae12a02006-01-08 13:34:19 -0800189/*-------------------------------------------------------------------------*/
190
191/* SPI devices should normally not be created by SPI device drivers; that
192 * would make them board-specific. Similarly with SPI master drivers.
193 * Device registration normally goes into like arch/.../mach.../board-YYY.c
194 * with other readonly (flashable) information about mainboard devices.
195 */
196
197struct boardinfo {
198 struct list_head list;
199 unsigned n_board_info;
200 struct spi_board_info board_info[0];
201};
202
203static LIST_HEAD(board_list);
Matthias Kaehlcke94040822007-07-17 04:04:16 -0700204static DEFINE_MUTEX(board_lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800205
Grant Likelydc87c982008-05-15 16:50:22 -0600206/**
207 * spi_alloc_device - Allocate a new SPI device
208 * @master: Controller to which device is connected
209 * Context: can sleep
210 *
211 * Allows a driver to allocate and initialize a spi_device without
212 * registering it immediately. This allows a driver to directly
213 * fill the spi_device with device parameters before calling
214 * spi_add_device() on it.
215 *
216 * Caller is responsible to call spi_add_device() on the returned
217 * spi_device structure to add it to the SPI master. If the caller
218 * needs to discard the spi_device without adding it, then it should
219 * call spi_dev_put() on it.
220 *
221 * Returns a pointer to the new device, or NULL.
222 */
223struct spi_device *spi_alloc_device(struct spi_master *master)
224{
225 struct spi_device *spi;
226 struct device *dev = master->dev.parent;
227
228 if (!spi_master_get(master))
229 return NULL;
230
231 spi = kzalloc(sizeof *spi, GFP_KERNEL);
232 if (!spi) {
233 dev_err(dev, "cannot alloc spi_device\n");
234 spi_master_put(master);
235 return NULL;
236 }
237
238 spi->master = master;
239 spi->dev.parent = dev;
240 spi->dev.bus = &spi_bus_type;
241 spi->dev.release = spidev_release;
242 device_initialize(&spi->dev);
243 return spi;
244}
245EXPORT_SYMBOL_GPL(spi_alloc_device);
246
247/**
248 * spi_add_device - Add spi_device allocated with spi_alloc_device
249 * @spi: spi_device to register
250 *
251 * Companion function to spi_alloc_device. Devices allocated with
252 * spi_alloc_device can be added onto the spi bus with this function.
253 *
David Brownelle48880e2008-08-15 00:40:44 -0700254 * Returns 0 on success; negative errno on failure
Grant Likelydc87c982008-05-15 16:50:22 -0600255 */
256int spi_add_device(struct spi_device *spi)
257{
David Brownelle48880e2008-08-15 00:40:44 -0700258 static DEFINE_MUTEX(spi_add_lock);
Grant Likelydc87c982008-05-15 16:50:22 -0600259 struct device *dev = spi->master->dev.parent;
Roman Tereshonkov8ec130a2010-04-16 09:52:59 +0000260 struct device *d;
Grant Likelydc87c982008-05-15 16:50:22 -0600261 int status;
262
263 /* Chipselects are numbered 0..max; validate. */
264 if (spi->chip_select >= spi->master->num_chipselect) {
265 dev_err(dev, "cs%d >= max %d\n",
266 spi->chip_select,
267 spi->master->num_chipselect);
268 return -EINVAL;
269 }
270
271 /* Set the bus ID string */
Kay Sievers35f74fc2009-01-06 10:44:37 -0800272 dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
Grant Likelydc87c982008-05-15 16:50:22 -0600273 spi->chip_select);
274
David Brownelle48880e2008-08-15 00:40:44 -0700275
276 /* We need to make sure there's no other device with this
277 * chipselect **BEFORE** we call setup(), else we'll trash
278 * its configuration. Lock against concurrent add() calls.
279 */
280 mutex_lock(&spi_add_lock);
281
Roman Tereshonkov8ec130a2010-04-16 09:52:59 +0000282 d = bus_find_device_by_name(&spi_bus_type, NULL, dev_name(&spi->dev));
283 if (d != NULL) {
David Brownelle48880e2008-08-15 00:40:44 -0700284 dev_err(dev, "chipselect %d already in use\n",
285 spi->chip_select);
Roman Tereshonkov8ec130a2010-04-16 09:52:59 +0000286 put_device(d);
David Brownelle48880e2008-08-15 00:40:44 -0700287 status = -EBUSY;
288 goto done;
289 }
290
291 /* Drivers may modify this initial i/o setup, but will
292 * normally rely on the device being setup. Devices
293 * using SPI_CS_HIGH can't coexist well otherwise...
294 */
David Brownell7d077192009-06-17 16:26:03 -0700295 status = spi_setup(spi);
Grant Likelydc87c982008-05-15 16:50:22 -0600296 if (status < 0) {
297 dev_err(dev, "can't %s %s, status %d\n",
Kay Sievers35f74fc2009-01-06 10:44:37 -0800298 "setup", dev_name(&spi->dev), status);
David Brownelle48880e2008-08-15 00:40:44 -0700299 goto done;
Grant Likelydc87c982008-05-15 16:50:22 -0600300 }
301
David Brownelle48880e2008-08-15 00:40:44 -0700302 /* Device may be bound to an active driver when this returns */
Grant Likelydc87c982008-05-15 16:50:22 -0600303 status = device_add(&spi->dev);
David Brownelle48880e2008-08-15 00:40:44 -0700304 if (status < 0)
Grant Likelydc87c982008-05-15 16:50:22 -0600305 dev_err(dev, "can't %s %s, status %d\n",
Kay Sievers35f74fc2009-01-06 10:44:37 -0800306 "add", dev_name(&spi->dev), status);
David Brownelle48880e2008-08-15 00:40:44 -0700307 else
Kay Sievers35f74fc2009-01-06 10:44:37 -0800308 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
Grant Likelydc87c982008-05-15 16:50:22 -0600309
David Brownelle48880e2008-08-15 00:40:44 -0700310done:
311 mutex_unlock(&spi_add_lock);
312 return status;
Grant Likelydc87c982008-05-15 16:50:22 -0600313}
314EXPORT_SYMBOL_GPL(spi_add_device);
David Brownell8ae12a02006-01-08 13:34:19 -0800315
David Brownell33e34dc2007-05-08 00:32:21 -0700316/**
317 * spi_new_device - instantiate one new SPI device
318 * @master: Controller to which device is connected
319 * @chip: Describes the SPI device
320 * Context: can sleep
321 *
322 * On typical mainboards, this is purely internal; and it's not needed
David Brownell8ae12a02006-01-08 13:34:19 -0800323 * after board init creates the hard-wired devices. Some development
324 * platforms may not be able to use spi_register_board_info though, and
325 * this is exported so that for example a USB or parport based adapter
326 * driver could add devices (which it would learn about out-of-band).
David Brownell082c8cb2007-07-31 00:39:45 -0700327 *
328 * Returns the new device, or NULL.
David Brownell8ae12a02006-01-08 13:34:19 -0800329 */
Adrian Bunke9d5a462007-03-26 21:32:23 -0800330struct spi_device *spi_new_device(struct spi_master *master,
331 struct spi_board_info *chip)
David Brownell8ae12a02006-01-08 13:34:19 -0800332{
333 struct spi_device *proxy;
David Brownell8ae12a02006-01-08 13:34:19 -0800334 int status;
335
David Brownell082c8cb2007-07-31 00:39:45 -0700336 /* NOTE: caller did any chip->bus_num checks necessary.
337 *
338 * Also, unless we change the return value convention to use
339 * error-or-pointer (not NULL-or-pointer), troubleshootability
340 * suggests syslogged diagnostics are best here (ugh).
341 */
342
Grant Likelydc87c982008-05-15 16:50:22 -0600343 proxy = spi_alloc_device(master);
344 if (!proxy)
David Brownell8ae12a02006-01-08 13:34:19 -0800345 return NULL;
346
Grant Likely102eb972008-07-23 21:29:55 -0700347 WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
348
David Brownell8ae12a02006-01-08 13:34:19 -0800349 proxy->chip_select = chip->chip_select;
350 proxy->max_speed_hz = chip->max_speed_hz;
David Brownell980a01c2006-06-28 07:47:15 -0700351 proxy->mode = chip->mode;
David Brownell8ae12a02006-01-08 13:34:19 -0800352 proxy->irq = chip->irq;
Grant Likely102eb972008-07-23 21:29:55 -0700353 strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
David Brownell8ae12a02006-01-08 13:34:19 -0800354 proxy->dev.platform_data = (void *) chip->platform_data;
355 proxy->controller_data = chip->controller_data;
356 proxy->controller_state = NULL;
David Brownell8ae12a02006-01-08 13:34:19 -0800357
Grant Likelydc87c982008-05-15 16:50:22 -0600358 status = spi_add_device(proxy);
David Brownell8ae12a02006-01-08 13:34:19 -0800359 if (status < 0) {
Grant Likelydc87c982008-05-15 16:50:22 -0600360 spi_dev_put(proxy);
361 return NULL;
David Brownell8ae12a02006-01-08 13:34:19 -0800362 }
363
David Brownell8ae12a02006-01-08 13:34:19 -0800364 return proxy;
365}
366EXPORT_SYMBOL_GPL(spi_new_device);
367
David Brownell33e34dc2007-05-08 00:32:21 -0700368/**
369 * spi_register_board_info - register SPI devices for a given board
370 * @info: array of chip descriptors
371 * @n: how many descriptors are provided
372 * Context: can sleep
373 *
David Brownell8ae12a02006-01-08 13:34:19 -0800374 * Board-specific early init code calls this (probably during arch_initcall)
375 * with segments of the SPI device table. Any device nodes are created later,
376 * after the relevant parent SPI controller (bus_num) is defined. We keep
377 * this table of devices forever, so that reloading a controller driver will
378 * not make Linux forget about these hard-wired devices.
379 *
380 * Other code can also call this, e.g. a particular add-on board might provide
381 * SPI devices through its expansion connector, so code initializing that board
382 * would naturally declare its SPI devices.
383 *
384 * The board info passed can safely be __initdata ... but be careful of
385 * any embedded pointers (platform_data, etc), they're copied as-is.
386 */
387int __init
388spi_register_board_info(struct spi_board_info const *info, unsigned n)
389{
390 struct boardinfo *bi;
391
David Brownellb8852442006-01-08 13:34:23 -0800392 bi = kmalloc(sizeof(*bi) + n * sizeof *info, GFP_KERNEL);
David Brownell8ae12a02006-01-08 13:34:19 -0800393 if (!bi)
394 return -ENOMEM;
395 bi->n_board_info = n;
David Brownellb8852442006-01-08 13:34:23 -0800396 memcpy(bi->board_info, info, n * sizeof *info);
David Brownell8ae12a02006-01-08 13:34:19 -0800397
Matthias Kaehlcke94040822007-07-17 04:04:16 -0700398 mutex_lock(&board_lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800399 list_add_tail(&bi->list, &board_list);
Matthias Kaehlcke94040822007-07-17 04:04:16 -0700400 mutex_unlock(&board_lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800401 return 0;
402}
David Brownell8ae12a02006-01-08 13:34:19 -0800403
404/* FIXME someone should add support for a __setup("spi", ...) that
405 * creates board info from kernel command lines
406 */
407
Adrian Bunk149a6502007-07-21 04:37:52 -0700408static void scan_boardinfo(struct spi_master *master)
David Brownell8ae12a02006-01-08 13:34:19 -0800409{
410 struct boardinfo *bi;
David Brownell8ae12a02006-01-08 13:34:19 -0800411
Matthias Kaehlcke94040822007-07-17 04:04:16 -0700412 mutex_lock(&board_lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800413 list_for_each_entry(bi, &board_list, list) {
414 struct spi_board_info *chip = bi->board_info;
415 unsigned n;
416
417 for (n = bi->n_board_info; n > 0; n--, chip++) {
418 if (chip->bus_num != master->bus_num)
419 continue;
David Brownell082c8cb2007-07-31 00:39:45 -0700420 /* NOTE: this relies on spi_new_device to
421 * issue diagnostics when given bogus inputs
David Brownell8ae12a02006-01-08 13:34:19 -0800422 */
David Brownell8ae12a02006-01-08 13:34:19 -0800423 (void) spi_new_device(master, chip);
424 }
425 }
Matthias Kaehlcke94040822007-07-17 04:04:16 -0700426 mutex_unlock(&board_lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800427}
428
429/*-------------------------------------------------------------------------*/
430
Tony Jones49dce682007-10-16 01:27:48 -0700431static void spi_master_release(struct device *dev)
David Brownell8ae12a02006-01-08 13:34:19 -0800432{
433 struct spi_master *master;
434
Tony Jones49dce682007-10-16 01:27:48 -0700435 master = container_of(dev, struct spi_master, dev);
David Brownell8ae12a02006-01-08 13:34:19 -0800436 kfree(master);
437}
438
439static struct class spi_master_class = {
440 .name = "spi_master",
441 .owner = THIS_MODULE,
Tony Jones49dce682007-10-16 01:27:48 -0700442 .dev_release = spi_master_release,
David Brownell8ae12a02006-01-08 13:34:19 -0800443};
444
445
446/**
447 * spi_alloc_master - allocate SPI master controller
448 * @dev: the controller, possibly using the platform_bus
David Brownell33e34dc2007-05-08 00:32:21 -0700449 * @size: how much zeroed driver-private data to allocate; the pointer to this
Tony Jones49dce682007-10-16 01:27:48 -0700450 * memory is in the driver_data field of the returned device,
David Brownell0c868462006-01-08 13:34:25 -0800451 * accessible with spi_master_get_devdata().
David Brownell33e34dc2007-05-08 00:32:21 -0700452 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800453 *
454 * This call is used only by SPI master controller drivers, which are the
455 * only ones directly touching chip registers. It's how they allocate
dmitry pervushinba1a0512006-05-20 15:00:14 -0700456 * an spi_master structure, prior to calling spi_register_master().
David Brownell8ae12a02006-01-08 13:34:19 -0800457 *
458 * This must be called from context that can sleep. It returns the SPI
459 * master structure on success, else NULL.
460 *
461 * The caller is responsible for assigning the bus number and initializing
dmitry pervushinba1a0512006-05-20 15:00:14 -0700462 * the master's methods before calling spi_register_master(); and (after errors
David Brownell0c868462006-01-08 13:34:25 -0800463 * adding the device) calling spi_master_put() to prevent a memory leak.
David Brownell8ae12a02006-01-08 13:34:19 -0800464 */
Adrian Bunke9d5a462007-03-26 21:32:23 -0800465struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
David Brownell8ae12a02006-01-08 13:34:19 -0800466{
467 struct spi_master *master;
468
David Brownell0c868462006-01-08 13:34:25 -0800469 if (!dev)
470 return NULL;
471
Christoph Lametere94b1762006-12-06 20:33:17 -0800472 master = kzalloc(size + sizeof *master, GFP_KERNEL);
David Brownell8ae12a02006-01-08 13:34:19 -0800473 if (!master)
474 return NULL;
475
Tony Jones49dce682007-10-16 01:27:48 -0700476 device_initialize(&master->dev);
477 master->dev.class = &spi_master_class;
478 master->dev.parent = get_device(dev);
David Brownell0c868462006-01-08 13:34:25 -0800479 spi_master_set_devdata(master, &master[1]);
David Brownell8ae12a02006-01-08 13:34:19 -0800480
481 return master;
482}
483EXPORT_SYMBOL_GPL(spi_alloc_master);
484
485/**
486 * spi_register_master - register SPI master controller
487 * @master: initialized master, originally from spi_alloc_master()
David Brownell33e34dc2007-05-08 00:32:21 -0700488 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800489 *
490 * SPI master controllers connect to their drivers using some non-SPI bus,
491 * such as the platform bus. The final stage of probe() in that code
492 * includes calling spi_register_master() to hook up to this SPI bus glue.
493 *
494 * SPI controllers use board specific (often SOC specific) bus numbers,
495 * and board-specific addressing for SPI devices combines those numbers
496 * with chip select numbers. Since SPI does not directly support dynamic
497 * device identification, boards need configuration tables telling which
498 * chip is at which address.
499 *
500 * This must be called from context that can sleep. It returns zero on
501 * success, else a negative error code (dropping the master's refcount).
David Brownell0c868462006-01-08 13:34:25 -0800502 * After a successful return, the caller is responsible for calling
503 * spi_unregister_master().
David Brownell8ae12a02006-01-08 13:34:19 -0800504 */
Adrian Bunke9d5a462007-03-26 21:32:23 -0800505int spi_register_master(struct spi_master *master)
David Brownell8ae12a02006-01-08 13:34:19 -0800506{
David Brownelle44a45a2007-06-03 13:50:40 -0700507 static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
Tony Jones49dce682007-10-16 01:27:48 -0700508 struct device *dev = master->dev.parent;
David Brownell8ae12a02006-01-08 13:34:19 -0800509 int status = -ENODEV;
510 int dynamic = 0;
511
David Brownell0c868462006-01-08 13:34:25 -0800512 if (!dev)
513 return -ENODEV;
514
David Brownell082c8cb2007-07-31 00:39:45 -0700515 /* even if it's just one always-selected device, there must
516 * be at least one chipselect
517 */
518 if (master->num_chipselect == 0)
519 return -EINVAL;
520
David Brownell8ae12a02006-01-08 13:34:19 -0800521 /* convention: dynamically assigned bus IDs count down from the max */
David Brownella020ed72006-04-03 15:49:04 -0700522 if (master->bus_num < 0) {
David Brownell082c8cb2007-07-31 00:39:45 -0700523 /* FIXME switch to an IDR based scheme, something like
524 * I2C now uses, so we can't run out of "dynamic" IDs
525 */
David Brownell8ae12a02006-01-08 13:34:19 -0800526 master->bus_num = atomic_dec_return(&dyn_bus_id);
David Brownellb8852442006-01-08 13:34:23 -0800527 dynamic = 1;
David Brownell8ae12a02006-01-08 13:34:19 -0800528 }
529
Ernst Schwabcf32b712010-06-28 17:49:29 -0700530 spin_lock_init(&master->bus_lock_spinlock);
531 mutex_init(&master->bus_lock_mutex);
532 master->bus_lock_flag = 0;
533
David Brownell8ae12a02006-01-08 13:34:19 -0800534 /* register the device, then userspace will see it.
535 * registration fails if the bus ID is in use.
536 */
Kay Sievers35f74fc2009-01-06 10:44:37 -0800537 dev_set_name(&master->dev, "spi%u", master->bus_num);
Tony Jones49dce682007-10-16 01:27:48 -0700538 status = device_add(&master->dev);
David Brownellb8852442006-01-08 13:34:23 -0800539 if (status < 0)
David Brownell8ae12a02006-01-08 13:34:19 -0800540 goto done;
Kay Sievers35f74fc2009-01-06 10:44:37 -0800541 dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
David Brownell8ae12a02006-01-08 13:34:19 -0800542 dynamic ? " (dynamic)" : "");
543
544 /* populate children from any spi device tables */
545 scan_boardinfo(master);
546 status = 0;
547done:
548 return status;
549}
550EXPORT_SYMBOL_GPL(spi_register_master);
551
552
Atsushi Nemoto350d0072007-11-14 16:59:22 -0800553static int __unregister(struct device *dev, void *master_dev)
David Brownell8ae12a02006-01-08 13:34:19 -0800554{
555 /* note: before about 2.6.14-rc1 this would corrupt memory: */
Atsushi Nemoto350d0072007-11-14 16:59:22 -0800556 if (dev != master_dev)
557 spi_unregister_device(to_spi_device(dev));
David Brownell8ae12a02006-01-08 13:34:19 -0800558 return 0;
559}
560
561/**
562 * spi_unregister_master - unregister SPI master controller
563 * @master: the master being unregistered
David Brownell33e34dc2007-05-08 00:32:21 -0700564 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800565 *
566 * This call is used only by SPI master controller drivers, which are the
567 * only ones directly touching chip registers.
568 *
569 * This must be called from context that can sleep.
570 */
571void spi_unregister_master(struct spi_master *master)
572{
Jeff Garzik89fc9a12006-12-06 20:35:35 -0800573 int dummy;
574
Atsushi Nemoto350d0072007-11-14 16:59:22 -0800575 dummy = device_for_each_child(master->dev.parent, &master->dev,
576 __unregister);
Tony Jones49dce682007-10-16 01:27:48 -0700577 device_unregister(&master->dev);
David Brownell8ae12a02006-01-08 13:34:19 -0800578}
579EXPORT_SYMBOL_GPL(spi_unregister_master);
580
Dave Young5ed2c832008-01-22 15:14:18 +0800581static int __spi_master_match(struct device *dev, void *data)
582{
583 struct spi_master *m;
584 u16 *bus_num = data;
585
586 m = container_of(dev, struct spi_master, dev);
587 return m->bus_num == *bus_num;
588}
589
David Brownell8ae12a02006-01-08 13:34:19 -0800590/**
591 * spi_busnum_to_master - look up master associated with bus_num
592 * @bus_num: the master's bus number
David Brownell33e34dc2007-05-08 00:32:21 -0700593 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800594 *
595 * This call may be used with devices that are registered after
596 * arch init time. It returns a refcounted pointer to the relevant
597 * spi_master (which the caller must release), or NULL if there is
598 * no such master registered.
599 */
600struct spi_master *spi_busnum_to_master(u16 bus_num)
601{
Tony Jones49dce682007-10-16 01:27:48 -0700602 struct device *dev;
Atsushi Nemoto1e9a51d2007-01-26 00:56:54 -0800603 struct spi_master *master = NULL;
David Brownell8ae12a02006-01-08 13:34:19 -0800604
Greg Kroah-Hartman695794a2008-05-22 17:21:08 -0400605 dev = class_find_device(&spi_master_class, NULL, &bus_num,
Dave Young5ed2c832008-01-22 15:14:18 +0800606 __spi_master_match);
607 if (dev)
608 master = container_of(dev, struct spi_master, dev);
609 /* reference got in class_find_device */
Atsushi Nemoto1e9a51d2007-01-26 00:56:54 -0800610 return master;
David Brownell8ae12a02006-01-08 13:34:19 -0800611}
612EXPORT_SYMBOL_GPL(spi_busnum_to_master);
613
614
615/*-------------------------------------------------------------------------*/
616
David Brownell7d077192009-06-17 16:26:03 -0700617/* Core methods for SPI master protocol drivers. Some of the
618 * other core methods are currently defined as inline functions.
619 */
620
621/**
622 * spi_setup - setup SPI mode and clock rate
623 * @spi: the device whose settings are being modified
624 * Context: can sleep, and no requests are queued to the device
625 *
626 * SPI protocol drivers may need to update the transfer mode if the
627 * device doesn't work with its default. They may likewise need
628 * to update clock rates or word sizes from initial values. This function
629 * changes those settings, and must be called from a context that can sleep.
630 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
631 * effect the next time the device is selected and data is transferred to
632 * or from it. When this function returns, the spi device is deselected.
633 *
634 * Note that this call will fail if the protocol driver specifies an option
635 * that the underlying controller or its driver does not support. For
636 * example, not all hardware supports wire transfers using nine bit words,
637 * LSB-first wire encoding, or active-high chipselects.
638 */
639int spi_setup(struct spi_device *spi)
640{
David Brownelle7db06b2009-06-17 16:26:04 -0700641 unsigned bad_bits;
David Brownell7d077192009-06-17 16:26:03 -0700642 int status;
643
David Brownelle7db06b2009-06-17 16:26:04 -0700644 /* help drivers fail *cleanly* when they need options
645 * that aren't supported with their current master
646 */
647 bad_bits = spi->mode & ~spi->master->mode_bits;
648 if (bad_bits) {
649 dev_dbg(&spi->dev, "setup: unsupported mode bits %x\n",
650 bad_bits);
651 return -EINVAL;
652 }
653
David Brownell7d077192009-06-17 16:26:03 -0700654 if (!spi->bits_per_word)
655 spi->bits_per_word = 8;
656
657 status = spi->master->setup(spi);
658
659 dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s"
660 "%u bits/w, %u Hz max --> %d\n",
661 (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
662 (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
663 (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
664 (spi->mode & SPI_3WIRE) ? "3wire, " : "",
665 (spi->mode & SPI_LOOP) ? "loopback, " : "",
666 spi->bits_per_word, spi->max_speed_hz,
667 status);
668
669 return status;
670}
671EXPORT_SYMBOL_GPL(spi_setup);
672
Ernst Schwabcf32b712010-06-28 17:49:29 -0700673static int __spi_async(struct spi_device *spi, struct spi_message *message)
674{
675 struct spi_master *master = spi->master;
676
677 /* Half-duplex links include original MicroWire, and ones with
678 * only one data pin like SPI_3WIRE (switches direction) or where
679 * either MOSI or MISO is missing. They can also be caused by
680 * software limitations.
681 */
682 if ((master->flags & SPI_MASTER_HALF_DUPLEX)
683 || (spi->mode & SPI_3WIRE)) {
684 struct spi_transfer *xfer;
685 unsigned flags = master->flags;
686
687 list_for_each_entry(xfer, &message->transfers, transfer_list) {
688 if (xfer->rx_buf && xfer->tx_buf)
689 return -EINVAL;
690 if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
691 return -EINVAL;
692 if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
693 return -EINVAL;
694 }
695 }
696
697 message->spi = spi;
698 message->status = -EINPROGRESS;
699 return master->transfer(spi, message);
700}
701
David Brownell568d0692009-09-22 16:46:18 -0700702/**
703 * spi_async - asynchronous SPI transfer
704 * @spi: device with which data will be exchanged
705 * @message: describes the data transfers, including completion callback
706 * Context: any (irqs may be blocked, etc)
707 *
708 * This call may be used in_irq and other contexts which can't sleep,
709 * as well as from task contexts which can sleep.
710 *
711 * The completion callback is invoked in a context which can't sleep.
712 * Before that invocation, the value of message->status is undefined.
713 * When the callback is issued, message->status holds either zero (to
714 * indicate complete success) or a negative error code. After that
715 * callback returns, the driver which issued the transfer request may
716 * deallocate the associated memory; it's no longer in use by any SPI
717 * core or controller driver code.
718 *
719 * Note that although all messages to a spi_device are handled in
720 * FIFO order, messages may go to different devices in other orders.
721 * Some device might be higher priority, or have various "hard" access
722 * time requirements, for example.
723 *
724 * On detection of any fault during the transfer, processing of
725 * the entire message is aborted, and the device is deselected.
726 * Until returning from the associated message completion callback,
727 * no other spi_message queued to that device will be processed.
728 * (This rule applies equally to all the synchronous transfer calls,
729 * which are wrappers around this core asynchronous primitive.)
730 */
731int spi_async(struct spi_device *spi, struct spi_message *message)
732{
733 struct spi_master *master = spi->master;
Ernst Schwabcf32b712010-06-28 17:49:29 -0700734 int ret;
735 unsigned long flags;
David Brownell568d0692009-09-22 16:46:18 -0700736
Ernst Schwabcf32b712010-06-28 17:49:29 -0700737 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
David Brownell568d0692009-09-22 16:46:18 -0700738
Ernst Schwabcf32b712010-06-28 17:49:29 -0700739 if (master->bus_lock_flag)
740 ret = -EBUSY;
741 else
742 ret = __spi_async(spi, message);
David Brownell568d0692009-09-22 16:46:18 -0700743
Ernst Schwabcf32b712010-06-28 17:49:29 -0700744 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
745
746 return ret;
David Brownell568d0692009-09-22 16:46:18 -0700747}
748EXPORT_SYMBOL_GPL(spi_async);
749
Ernst Schwabcf32b712010-06-28 17:49:29 -0700750/**
751 * spi_async_locked - version of spi_async with exclusive bus usage
752 * @spi: device with which data will be exchanged
753 * @message: describes the data transfers, including completion callback
754 * Context: any (irqs may be blocked, etc)
755 *
756 * This call may be used in_irq and other contexts which can't sleep,
757 * as well as from task contexts which can sleep.
758 *
759 * The completion callback is invoked in a context which can't sleep.
760 * Before that invocation, the value of message->status is undefined.
761 * When the callback is issued, message->status holds either zero (to
762 * indicate complete success) or a negative error code. After that
763 * callback returns, the driver which issued the transfer request may
764 * deallocate the associated memory; it's no longer in use by any SPI
765 * core or controller driver code.
766 *
767 * Note that although all messages to a spi_device are handled in
768 * FIFO order, messages may go to different devices in other orders.
769 * Some device might be higher priority, or have various "hard" access
770 * time requirements, for example.
771 *
772 * On detection of any fault during the transfer, processing of
773 * the entire message is aborted, and the device is deselected.
774 * Until returning from the associated message completion callback,
775 * no other spi_message queued to that device will be processed.
776 * (This rule applies equally to all the synchronous transfer calls,
777 * which are wrappers around this core asynchronous primitive.)
778 */
779int spi_async_locked(struct spi_device *spi, struct spi_message *message)
780{
781 struct spi_master *master = spi->master;
782 int ret;
783 unsigned long flags;
784
785 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
786
787 ret = __spi_async(spi, message);
788
789 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
790
791 return ret;
792
793}
794EXPORT_SYMBOL_GPL(spi_async_locked);
795
David Brownell7d077192009-06-17 16:26:03 -0700796
797/*-------------------------------------------------------------------------*/
798
799/* Utility methods for SPI master protocol drivers, layered on
800 * top of the core. Some other utility methods are defined as
801 * inline functions.
802 */
803
Andrew Morton5d870c82006-01-11 11:23:49 -0800804static void spi_complete(void *arg)
805{
806 complete(arg);
807}
808
Ernst Schwabcf32b712010-06-28 17:49:29 -0700809static int __spi_sync(struct spi_device *spi, struct spi_message *message,
810 int bus_locked)
811{
812 DECLARE_COMPLETION_ONSTACK(done);
813 int status;
814 struct spi_master *master = spi->master;
815
816 message->complete = spi_complete;
817 message->context = &done;
818
819 if (!bus_locked)
820 mutex_lock(&master->bus_lock_mutex);
821
822 status = spi_async_locked(spi, message);
823
824 if (!bus_locked)
825 mutex_unlock(&master->bus_lock_mutex);
826
827 if (status == 0) {
828 wait_for_completion(&done);
829 status = message->status;
830 }
831 message->context = NULL;
832 return status;
833}
834
David Brownell8ae12a02006-01-08 13:34:19 -0800835/**
836 * spi_sync - blocking/synchronous SPI data transfers
837 * @spi: device with which data will be exchanged
838 * @message: describes the data transfers
David Brownell33e34dc2007-05-08 00:32:21 -0700839 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800840 *
841 * This call may only be used from a context that may sleep. The sleep
842 * is non-interruptible, and has no timeout. Low-overhead controller
843 * drivers may DMA directly into and out of the message buffers.
844 *
845 * Note that the SPI device's chip select is active during the message,
846 * and then is normally disabled between messages. Drivers for some
847 * frequently-used devices may want to minimize costs of selecting a chip,
848 * by leaving it selected in anticipation that the next message will go
849 * to the same chip. (That may increase power usage.)
850 *
David Brownell0c868462006-01-08 13:34:25 -0800851 * Also, the caller is guaranteeing that the memory associated with the
852 * message will not be freed before this call returns.
853 *
Marc Pignat9b938b72007-12-04 23:45:10 -0800854 * It returns zero on success, else a negative error code.
David Brownell8ae12a02006-01-08 13:34:19 -0800855 */
856int spi_sync(struct spi_device *spi, struct spi_message *message)
857{
Ernst Schwabcf32b712010-06-28 17:49:29 -0700858 return __spi_sync(spi, message, 0);
David Brownell8ae12a02006-01-08 13:34:19 -0800859}
860EXPORT_SYMBOL_GPL(spi_sync);
861
Ernst Schwabcf32b712010-06-28 17:49:29 -0700862/**
863 * spi_sync_locked - version of spi_sync with exclusive bus usage
864 * @spi: device with which data will be exchanged
865 * @message: describes the data transfers
866 * Context: can sleep
867 *
868 * This call may only be used from a context that may sleep. The sleep
869 * is non-interruptible, and has no timeout. Low-overhead controller
870 * drivers may DMA directly into and out of the message buffers.
871 *
872 * This call should be used by drivers that require exclusive access to the
873 * SPI bus. It has to be preceeded by a spi_bus_lock call. The SPI bus must
874 * be released by a spi_bus_unlock call when the exclusive access is over.
875 *
876 * It returns zero on success, else a negative error code.
877 */
878int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
879{
880 return __spi_sync(spi, message, 1);
881}
882EXPORT_SYMBOL_GPL(spi_sync_locked);
883
884/**
885 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
886 * @master: SPI bus master that should be locked for exclusive bus access
887 * Context: can sleep
888 *
889 * This call may only be used from a context that may sleep. The sleep
890 * is non-interruptible, and has no timeout.
891 *
892 * This call should be used by drivers that require exclusive access to the
893 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
894 * exclusive access is over. Data transfer must be done by spi_sync_locked
895 * and spi_async_locked calls when the SPI bus lock is held.
896 *
897 * It returns zero on success, else a negative error code.
898 */
899int spi_bus_lock(struct spi_master *master)
900{
901 unsigned long flags;
902
903 mutex_lock(&master->bus_lock_mutex);
904
905 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
906 master->bus_lock_flag = 1;
907 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
908
909 /* mutex remains locked until spi_bus_unlock is called */
910
911 return 0;
912}
913EXPORT_SYMBOL_GPL(spi_bus_lock);
914
915/**
916 * spi_bus_unlock - release the lock for exclusive SPI bus usage
917 * @master: SPI bus master that was locked for exclusive bus access
918 * Context: can sleep
919 *
920 * This call may only be used from a context that may sleep. The sleep
921 * is non-interruptible, and has no timeout.
922 *
923 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
924 * call.
925 *
926 * It returns zero on success, else a negative error code.
927 */
928int spi_bus_unlock(struct spi_master *master)
929{
930 master->bus_lock_flag = 0;
931
932 mutex_unlock(&master->bus_lock_mutex);
933
934 return 0;
935}
936EXPORT_SYMBOL_GPL(spi_bus_unlock);
937
David Brownella9948b62006-04-02 10:37:40 -0800938/* portable code must never pass more than 32 bytes */
939#define SPI_BUFSIZ max(32,SMP_CACHE_BYTES)
David Brownell8ae12a02006-01-08 13:34:19 -0800940
941static u8 *buf;
942
943/**
944 * spi_write_then_read - SPI synchronous write followed by read
945 * @spi: device with which data will be exchanged
946 * @txbuf: data to be written (need not be dma-safe)
947 * @n_tx: size of txbuf, in bytes
Jiri Pirko27570492009-06-17 16:26:06 -0700948 * @rxbuf: buffer into which data will be read (need not be dma-safe)
949 * @n_rx: size of rxbuf, in bytes
David Brownell33e34dc2007-05-08 00:32:21 -0700950 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800951 *
952 * This performs a half duplex MicroWire style transaction with the
953 * device, sending txbuf and then reading rxbuf. The return value
954 * is zero for success, else a negative errno status code.
David Brownellb8852442006-01-08 13:34:23 -0800955 * This call may only be used from a context that may sleep.
David Brownell8ae12a02006-01-08 13:34:19 -0800956 *
David Brownell0c868462006-01-08 13:34:25 -0800957 * Parameters to this routine are always copied using a small buffer;
David Brownell33e34dc2007-05-08 00:32:21 -0700958 * portable code should never use this for more than 32 bytes.
959 * Performance-sensitive or bulk transfer code should instead use
David Brownell0c868462006-01-08 13:34:25 -0800960 * spi_{async,sync}() calls with dma-safe buffers.
David Brownell8ae12a02006-01-08 13:34:19 -0800961 */
962int spi_write_then_read(struct spi_device *spi,
963 const u8 *txbuf, unsigned n_tx,
964 u8 *rxbuf, unsigned n_rx)
965{
David Brownell068f4072007-12-04 23:45:09 -0800966 static DEFINE_MUTEX(lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800967
968 int status;
969 struct spi_message message;
David Brownellbdff5492009-04-13 14:39:57 -0700970 struct spi_transfer x[2];
David Brownell8ae12a02006-01-08 13:34:19 -0800971 u8 *local_buf;
972
973 /* Use preallocated DMA-safe buffer. We can't avoid copying here,
974 * (as a pure convenience thing), but we can keep heap costs
975 * out of the hot path ...
976 */
977 if ((n_tx + n_rx) > SPI_BUFSIZ)
978 return -EINVAL;
979
Vitaly Wool8275c642006-01-08 13:34:28 -0800980 spi_message_init(&message);
David Brownellbdff5492009-04-13 14:39:57 -0700981 memset(x, 0, sizeof x);
982 if (n_tx) {
983 x[0].len = n_tx;
984 spi_message_add_tail(&x[0], &message);
985 }
986 if (n_rx) {
987 x[1].len = n_rx;
988 spi_message_add_tail(&x[1], &message);
989 }
Vitaly Wool8275c642006-01-08 13:34:28 -0800990
David Brownell8ae12a02006-01-08 13:34:19 -0800991 /* ... unless someone else is using the pre-allocated buffer */
David Brownell068f4072007-12-04 23:45:09 -0800992 if (!mutex_trylock(&lock)) {
David Brownell8ae12a02006-01-08 13:34:19 -0800993 local_buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
994 if (!local_buf)
995 return -ENOMEM;
996 } else
997 local_buf = buf;
998
David Brownell8ae12a02006-01-08 13:34:19 -0800999 memcpy(local_buf, txbuf, n_tx);
David Brownellbdff5492009-04-13 14:39:57 -07001000 x[0].tx_buf = local_buf;
1001 x[1].rx_buf = local_buf + n_tx;
David Brownell8ae12a02006-01-08 13:34:19 -08001002
1003 /* do the i/o */
David Brownell8ae12a02006-01-08 13:34:19 -08001004 status = spi_sync(spi, &message);
Marc Pignat9b938b72007-12-04 23:45:10 -08001005 if (status == 0)
David Brownellbdff5492009-04-13 14:39:57 -07001006 memcpy(rxbuf, x[1].rx_buf, n_rx);
David Brownell8ae12a02006-01-08 13:34:19 -08001007
David Brownellbdff5492009-04-13 14:39:57 -07001008 if (x[0].tx_buf == buf)
David Brownell068f4072007-12-04 23:45:09 -08001009 mutex_unlock(&lock);
David Brownell8ae12a02006-01-08 13:34:19 -08001010 else
1011 kfree(local_buf);
1012
1013 return status;
1014}
1015EXPORT_SYMBOL_GPL(spi_write_then_read);
1016
1017/*-------------------------------------------------------------------------*/
1018
1019static int __init spi_init(void)
1020{
David Brownellb8852442006-01-08 13:34:23 -08001021 int status;
David Brownell8ae12a02006-01-08 13:34:19 -08001022
Christoph Lametere94b1762006-12-06 20:33:17 -08001023 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
David Brownellb8852442006-01-08 13:34:23 -08001024 if (!buf) {
1025 status = -ENOMEM;
1026 goto err0;
1027 }
1028
1029 status = bus_register(&spi_bus_type);
1030 if (status < 0)
1031 goto err1;
1032
1033 status = class_register(&spi_master_class);
1034 if (status < 0)
1035 goto err2;
David Brownell8ae12a02006-01-08 13:34:19 -08001036 return 0;
David Brownellb8852442006-01-08 13:34:23 -08001037
1038err2:
1039 bus_unregister(&spi_bus_type);
1040err1:
1041 kfree(buf);
1042 buf = NULL;
1043err0:
1044 return status;
David Brownell8ae12a02006-01-08 13:34:19 -08001045}
David Brownellb8852442006-01-08 13:34:23 -08001046
David Brownell8ae12a02006-01-08 13:34:19 -08001047/* board_info is normally registered in arch_initcall(),
1048 * but even essential drivers wait till later
David Brownellb8852442006-01-08 13:34:23 -08001049 *
1050 * REVISIT only boardinfo really needs static linking. the rest (device and
1051 * driver registration) _could_ be dynamically linked (modular) ... costs
1052 * include needing to have boardinfo data structures be much more public.
David Brownell8ae12a02006-01-08 13:34:19 -08001053 */
David Brownell673c0c02008-10-15 22:02:46 -07001054postcore_initcall(spi_init);
David Brownell8ae12a02006-01-08 13:34:19 -08001055