blob: 3734dc9708e12669070ab984cc2fe9f0fbee1b70 [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>
David Brownell8ae12a02006-01-08 13:34:19 -080026#include <linux/spi/spi.h>
27
28
David Brownellb8852442006-01-08 13:34:23 -080029/* SPI bustype and spi_master class are registered after board init code
30 * provides the SPI device tables, ensuring that both are present by the
31 * time controller driver registration causes spi_devices to "enumerate".
David Brownell8ae12a02006-01-08 13:34:19 -080032 */
33static void spidev_release(struct device *dev)
34{
Hans-Peter Nilsson0ffa0282007-02-12 00:52:45 -080035 struct spi_device *spi = to_spi_device(dev);
David Brownell8ae12a02006-01-08 13:34:19 -080036
37 /* spi masters may cleanup for released devices */
38 if (spi->master->cleanup)
39 spi->master->cleanup(spi);
40
David Brownell0c868462006-01-08 13:34:25 -080041 spi_master_put(spi->master);
David Brownell8ae12a02006-01-08 13:34:19 -080042 kfree(dev);
43}
44
45static ssize_t
46modalias_show(struct device *dev, struct device_attribute *a, char *buf)
47{
48 const struct spi_device *spi = to_spi_device(dev);
49
50 return snprintf(buf, BUS_ID_SIZE + 1, "%s\n", spi->modalias);
51}
52
53static struct device_attribute spi_dev_attrs[] = {
54 __ATTR_RO(modalias),
55 __ATTR_NULL,
56};
57
58/* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
59 * and the sysfs version makes coldplug work too.
60 */
61
62static int spi_match_device(struct device *dev, struct device_driver *drv)
63{
64 const struct spi_device *spi = to_spi_device(dev);
65
66 return strncmp(spi->modalias, drv->name, BUS_ID_SIZE) == 0;
67}
68
Kay Sievers7eff2e72007-08-14 15:15:12 +020069static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
David Brownell8ae12a02006-01-08 13:34:19 -080070{
71 const struct spi_device *spi = to_spi_device(dev);
72
Kay Sievers7eff2e72007-08-14 15:15:12 +020073 add_uevent_var(env, "MODALIAS=%s", spi->modalias);
David Brownell8ae12a02006-01-08 13:34:19 -080074 return 0;
75}
76
77#ifdef CONFIG_PM
78
David Brownell8ae12a02006-01-08 13:34:19 -080079static int spi_suspend(struct device *dev, pm_message_t message)
80{
David Brownell3c724262008-02-06 01:38:10 -080081 int value = 0;
David Brownellb8852442006-01-08 13:34:23 -080082 struct spi_driver *drv = to_spi_driver(dev->driver);
David Brownell8ae12a02006-01-08 13:34:19 -080083
David Brownell8ae12a02006-01-08 13:34:19 -080084 /* suspend will stop irqs and dma; no more i/o */
David Brownell3c724262008-02-06 01:38:10 -080085 if (drv) {
86 if (drv->suspend)
87 value = drv->suspend(to_spi_device(dev), message);
88 else
89 dev_dbg(dev, "... can't suspend\n");
90 }
David Brownell8ae12a02006-01-08 13:34:19 -080091 return value;
92}
93
94static int spi_resume(struct device *dev)
95{
David Brownell3c724262008-02-06 01:38:10 -080096 int value = 0;
David Brownellb8852442006-01-08 13:34:23 -080097 struct spi_driver *drv = to_spi_driver(dev->driver);
David Brownell8ae12a02006-01-08 13:34:19 -080098
David Brownell8ae12a02006-01-08 13:34:19 -080099 /* resume may restart the i/o queue */
David Brownell3c724262008-02-06 01:38:10 -0800100 if (drv) {
101 if (drv->resume)
102 value = drv->resume(to_spi_device(dev));
103 else
104 dev_dbg(dev, "... can't resume\n");
105 }
David Brownell8ae12a02006-01-08 13:34:19 -0800106 return value;
107}
108
109#else
110#define spi_suspend NULL
111#define spi_resume NULL
112#endif
113
114struct bus_type spi_bus_type = {
115 .name = "spi",
116 .dev_attrs = spi_dev_attrs,
117 .match = spi_match_device,
118 .uevent = spi_uevent,
119 .suspend = spi_suspend,
120 .resume = spi_resume,
121};
122EXPORT_SYMBOL_GPL(spi_bus_type);
123
David Brownellb8852442006-01-08 13:34:23 -0800124
125static int spi_drv_probe(struct device *dev)
126{
127 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
128
129 return sdrv->probe(to_spi_device(dev));
130}
131
132static int spi_drv_remove(struct device *dev)
133{
134 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
135
136 return sdrv->remove(to_spi_device(dev));
137}
138
139static void spi_drv_shutdown(struct device *dev)
140{
141 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
142
143 sdrv->shutdown(to_spi_device(dev));
144}
145
David Brownell33e34dc2007-05-08 00:32:21 -0700146/**
147 * spi_register_driver - register a SPI driver
148 * @sdrv: the driver to register
149 * Context: can sleep
150 */
David Brownellb8852442006-01-08 13:34:23 -0800151int spi_register_driver(struct spi_driver *sdrv)
152{
153 sdrv->driver.bus = &spi_bus_type;
154 if (sdrv->probe)
155 sdrv->driver.probe = spi_drv_probe;
156 if (sdrv->remove)
157 sdrv->driver.remove = spi_drv_remove;
158 if (sdrv->shutdown)
159 sdrv->driver.shutdown = spi_drv_shutdown;
160 return driver_register(&sdrv->driver);
161}
162EXPORT_SYMBOL_GPL(spi_register_driver);
163
David Brownell8ae12a02006-01-08 13:34:19 -0800164/*-------------------------------------------------------------------------*/
165
166/* SPI devices should normally not be created by SPI device drivers; that
167 * would make them board-specific. Similarly with SPI master drivers.
168 * Device registration normally goes into like arch/.../mach.../board-YYY.c
169 * with other readonly (flashable) information about mainboard devices.
170 */
171
172struct boardinfo {
173 struct list_head list;
174 unsigned n_board_info;
175 struct spi_board_info board_info[0];
176};
177
178static LIST_HEAD(board_list);
Matthias Kaehlcke94040822007-07-17 04:04:16 -0700179static DEFINE_MUTEX(board_lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800180
Grant Likelydc87c982008-05-15 16:50:22 -0600181/**
182 * spi_alloc_device - Allocate a new SPI device
183 * @master: Controller to which device is connected
184 * Context: can sleep
185 *
186 * Allows a driver to allocate and initialize a spi_device without
187 * registering it immediately. This allows a driver to directly
188 * fill the spi_device with device parameters before calling
189 * spi_add_device() on it.
190 *
191 * Caller is responsible to call spi_add_device() on the returned
192 * spi_device structure to add it to the SPI master. If the caller
193 * needs to discard the spi_device without adding it, then it should
194 * call spi_dev_put() on it.
195 *
196 * Returns a pointer to the new device, or NULL.
197 */
198struct spi_device *spi_alloc_device(struct spi_master *master)
199{
200 struct spi_device *spi;
201 struct device *dev = master->dev.parent;
202
203 if (!spi_master_get(master))
204 return NULL;
205
206 spi = kzalloc(sizeof *spi, GFP_KERNEL);
207 if (!spi) {
208 dev_err(dev, "cannot alloc spi_device\n");
209 spi_master_put(master);
210 return NULL;
211 }
212
213 spi->master = master;
214 spi->dev.parent = dev;
215 spi->dev.bus = &spi_bus_type;
216 spi->dev.release = spidev_release;
217 device_initialize(&spi->dev);
218 return spi;
219}
220EXPORT_SYMBOL_GPL(spi_alloc_device);
221
222/**
223 * spi_add_device - Add spi_device allocated with spi_alloc_device
224 * @spi: spi_device to register
225 *
226 * Companion function to spi_alloc_device. Devices allocated with
227 * spi_alloc_device can be added onto the spi bus with this function.
228 *
David Brownelle48880e2008-08-15 00:40:44 -0700229 * Returns 0 on success; negative errno on failure
Grant Likelydc87c982008-05-15 16:50:22 -0600230 */
231int spi_add_device(struct spi_device *spi)
232{
David Brownelle48880e2008-08-15 00:40:44 -0700233 static DEFINE_MUTEX(spi_add_lock);
Grant Likelydc87c982008-05-15 16:50:22 -0600234 struct device *dev = spi->master->dev.parent;
235 int status;
236
237 /* Chipselects are numbered 0..max; validate. */
238 if (spi->chip_select >= spi->master->num_chipselect) {
239 dev_err(dev, "cs%d >= max %d\n",
240 spi->chip_select,
241 spi->master->num_chipselect);
242 return -EINVAL;
243 }
244
245 /* Set the bus ID string */
246 snprintf(spi->dev.bus_id, sizeof spi->dev.bus_id,
247 "%s.%u", spi->master->dev.bus_id,
248 spi->chip_select);
249
David Brownelle48880e2008-08-15 00:40:44 -0700250
251 /* We need to make sure there's no other device with this
252 * chipselect **BEFORE** we call setup(), else we'll trash
253 * its configuration. Lock against concurrent add() calls.
254 */
255 mutex_lock(&spi_add_lock);
256
257 if (bus_find_device_by_name(&spi_bus_type, NULL, spi->dev.bus_id)
258 != NULL) {
259 dev_err(dev, "chipselect %d already in use\n",
260 spi->chip_select);
261 status = -EBUSY;
262 goto done;
263 }
264
265 /* Drivers may modify this initial i/o setup, but will
266 * normally rely on the device being setup. Devices
267 * using SPI_CS_HIGH can't coexist well otherwise...
268 */
Grant Likelydc87c982008-05-15 16:50:22 -0600269 status = spi->master->setup(spi);
270 if (status < 0) {
271 dev_err(dev, "can't %s %s, status %d\n",
272 "setup", spi->dev.bus_id, status);
David Brownelle48880e2008-08-15 00:40:44 -0700273 goto done;
Grant Likelydc87c982008-05-15 16:50:22 -0600274 }
275
David Brownelle48880e2008-08-15 00:40:44 -0700276 /* Device may be bound to an active driver when this returns */
Grant Likelydc87c982008-05-15 16:50:22 -0600277 status = device_add(&spi->dev);
David Brownelle48880e2008-08-15 00:40:44 -0700278 if (status < 0)
Grant Likelydc87c982008-05-15 16:50:22 -0600279 dev_err(dev, "can't %s %s, status %d\n",
280 "add", spi->dev.bus_id, status);
David Brownelle48880e2008-08-15 00:40:44 -0700281 else
282 dev_dbg(dev, "registered child %s\n", spi->dev.bus_id);
Grant Likelydc87c982008-05-15 16:50:22 -0600283
David Brownelle48880e2008-08-15 00:40:44 -0700284done:
285 mutex_unlock(&spi_add_lock);
286 return status;
Grant Likelydc87c982008-05-15 16:50:22 -0600287}
288EXPORT_SYMBOL_GPL(spi_add_device);
David Brownell8ae12a02006-01-08 13:34:19 -0800289
David Brownell33e34dc2007-05-08 00:32:21 -0700290/**
291 * spi_new_device - instantiate one new SPI device
292 * @master: Controller to which device is connected
293 * @chip: Describes the SPI device
294 * Context: can sleep
295 *
296 * On typical mainboards, this is purely internal; and it's not needed
David Brownell8ae12a02006-01-08 13:34:19 -0800297 * after board init creates the hard-wired devices. Some development
298 * platforms may not be able to use spi_register_board_info though, and
299 * this is exported so that for example a USB or parport based adapter
300 * driver could add devices (which it would learn about out-of-band).
David Brownell082c8cb2007-07-31 00:39:45 -0700301 *
302 * Returns the new device, or NULL.
David Brownell8ae12a02006-01-08 13:34:19 -0800303 */
Adrian Bunke9d5a462007-03-26 21:32:23 -0800304struct spi_device *spi_new_device(struct spi_master *master,
305 struct spi_board_info *chip)
David Brownell8ae12a02006-01-08 13:34:19 -0800306{
307 struct spi_device *proxy;
David Brownell8ae12a02006-01-08 13:34:19 -0800308 int status;
309
David Brownell082c8cb2007-07-31 00:39:45 -0700310 /* NOTE: caller did any chip->bus_num checks necessary.
311 *
312 * Also, unless we change the return value convention to use
313 * error-or-pointer (not NULL-or-pointer), troubleshootability
314 * suggests syslogged diagnostics are best here (ugh).
315 */
316
Grant Likelydc87c982008-05-15 16:50:22 -0600317 proxy = spi_alloc_device(master);
318 if (!proxy)
David Brownell8ae12a02006-01-08 13:34:19 -0800319 return NULL;
320
Grant Likely102eb972008-07-23 21:29:55 -0700321 WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
322
David Brownell8ae12a02006-01-08 13:34:19 -0800323 proxy->chip_select = chip->chip_select;
324 proxy->max_speed_hz = chip->max_speed_hz;
David Brownell980a01c2006-06-28 07:47:15 -0700325 proxy->mode = chip->mode;
David Brownell8ae12a02006-01-08 13:34:19 -0800326 proxy->irq = chip->irq;
Grant Likely102eb972008-07-23 21:29:55 -0700327 strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
David Brownell8ae12a02006-01-08 13:34:19 -0800328 proxy->dev.platform_data = (void *) chip->platform_data;
329 proxy->controller_data = chip->controller_data;
330 proxy->controller_state = NULL;
David Brownell8ae12a02006-01-08 13:34:19 -0800331
Grant Likelydc87c982008-05-15 16:50:22 -0600332 status = spi_add_device(proxy);
David Brownell8ae12a02006-01-08 13:34:19 -0800333 if (status < 0) {
Grant Likelydc87c982008-05-15 16:50:22 -0600334 spi_dev_put(proxy);
335 return NULL;
David Brownell8ae12a02006-01-08 13:34:19 -0800336 }
337
David Brownell8ae12a02006-01-08 13:34:19 -0800338 return proxy;
339}
340EXPORT_SYMBOL_GPL(spi_new_device);
341
David Brownell33e34dc2007-05-08 00:32:21 -0700342/**
343 * spi_register_board_info - register SPI devices for a given board
344 * @info: array of chip descriptors
345 * @n: how many descriptors are provided
346 * Context: can sleep
347 *
David Brownell8ae12a02006-01-08 13:34:19 -0800348 * Board-specific early init code calls this (probably during arch_initcall)
349 * with segments of the SPI device table. Any device nodes are created later,
350 * after the relevant parent SPI controller (bus_num) is defined. We keep
351 * this table of devices forever, so that reloading a controller driver will
352 * not make Linux forget about these hard-wired devices.
353 *
354 * Other code can also call this, e.g. a particular add-on board might provide
355 * SPI devices through its expansion connector, so code initializing that board
356 * would naturally declare its SPI devices.
357 *
358 * The board info passed can safely be __initdata ... but be careful of
359 * any embedded pointers (platform_data, etc), they're copied as-is.
360 */
361int __init
362spi_register_board_info(struct spi_board_info const *info, unsigned n)
363{
364 struct boardinfo *bi;
365
David Brownellb8852442006-01-08 13:34:23 -0800366 bi = kmalloc(sizeof(*bi) + n * sizeof *info, GFP_KERNEL);
David Brownell8ae12a02006-01-08 13:34:19 -0800367 if (!bi)
368 return -ENOMEM;
369 bi->n_board_info = n;
David Brownellb8852442006-01-08 13:34:23 -0800370 memcpy(bi->board_info, info, n * sizeof *info);
David Brownell8ae12a02006-01-08 13:34:19 -0800371
Matthias Kaehlcke94040822007-07-17 04:04:16 -0700372 mutex_lock(&board_lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800373 list_add_tail(&bi->list, &board_list);
Matthias Kaehlcke94040822007-07-17 04:04:16 -0700374 mutex_unlock(&board_lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800375 return 0;
376}
David Brownell8ae12a02006-01-08 13:34:19 -0800377
378/* FIXME someone should add support for a __setup("spi", ...) that
379 * creates board info from kernel command lines
380 */
381
Adrian Bunk149a6502007-07-21 04:37:52 -0700382static void scan_boardinfo(struct spi_master *master)
David Brownell8ae12a02006-01-08 13:34:19 -0800383{
384 struct boardinfo *bi;
David Brownell8ae12a02006-01-08 13:34:19 -0800385
Matthias Kaehlcke94040822007-07-17 04:04:16 -0700386 mutex_lock(&board_lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800387 list_for_each_entry(bi, &board_list, list) {
388 struct spi_board_info *chip = bi->board_info;
389 unsigned n;
390
391 for (n = bi->n_board_info; n > 0; n--, chip++) {
392 if (chip->bus_num != master->bus_num)
393 continue;
David Brownell082c8cb2007-07-31 00:39:45 -0700394 /* NOTE: this relies on spi_new_device to
395 * issue diagnostics when given bogus inputs
David Brownell8ae12a02006-01-08 13:34:19 -0800396 */
David Brownell8ae12a02006-01-08 13:34:19 -0800397 (void) spi_new_device(master, chip);
398 }
399 }
Matthias Kaehlcke94040822007-07-17 04:04:16 -0700400 mutex_unlock(&board_lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800401}
402
403/*-------------------------------------------------------------------------*/
404
Tony Jones49dce682007-10-16 01:27:48 -0700405static void spi_master_release(struct device *dev)
David Brownell8ae12a02006-01-08 13:34:19 -0800406{
407 struct spi_master *master;
408
Tony Jones49dce682007-10-16 01:27:48 -0700409 master = container_of(dev, struct spi_master, dev);
David Brownell8ae12a02006-01-08 13:34:19 -0800410 kfree(master);
411}
412
413static struct class spi_master_class = {
414 .name = "spi_master",
415 .owner = THIS_MODULE,
Tony Jones49dce682007-10-16 01:27:48 -0700416 .dev_release = spi_master_release,
David Brownell8ae12a02006-01-08 13:34:19 -0800417};
418
419
420/**
421 * spi_alloc_master - allocate SPI master controller
422 * @dev: the controller, possibly using the platform_bus
David Brownell33e34dc2007-05-08 00:32:21 -0700423 * @size: how much zeroed driver-private data to allocate; the pointer to this
Tony Jones49dce682007-10-16 01:27:48 -0700424 * memory is in the driver_data field of the returned device,
David Brownell0c868462006-01-08 13:34:25 -0800425 * accessible with spi_master_get_devdata().
David Brownell33e34dc2007-05-08 00:32:21 -0700426 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800427 *
428 * This call is used only by SPI master controller drivers, which are the
429 * only ones directly touching chip registers. It's how they allocate
dmitry pervushinba1a0512006-05-20 15:00:14 -0700430 * an spi_master structure, prior to calling spi_register_master().
David Brownell8ae12a02006-01-08 13:34:19 -0800431 *
432 * This must be called from context that can sleep. It returns the SPI
433 * master structure on success, else NULL.
434 *
435 * The caller is responsible for assigning the bus number and initializing
dmitry pervushinba1a0512006-05-20 15:00:14 -0700436 * the master's methods before calling spi_register_master(); and (after errors
David Brownell0c868462006-01-08 13:34:25 -0800437 * adding the device) calling spi_master_put() to prevent a memory leak.
David Brownell8ae12a02006-01-08 13:34:19 -0800438 */
Adrian Bunke9d5a462007-03-26 21:32:23 -0800439struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
David Brownell8ae12a02006-01-08 13:34:19 -0800440{
441 struct spi_master *master;
442
David Brownell0c868462006-01-08 13:34:25 -0800443 if (!dev)
444 return NULL;
445
Christoph Lametere94b1762006-12-06 20:33:17 -0800446 master = kzalloc(size + sizeof *master, GFP_KERNEL);
David Brownell8ae12a02006-01-08 13:34:19 -0800447 if (!master)
448 return NULL;
449
Tony Jones49dce682007-10-16 01:27:48 -0700450 device_initialize(&master->dev);
451 master->dev.class = &spi_master_class;
452 master->dev.parent = get_device(dev);
David Brownell0c868462006-01-08 13:34:25 -0800453 spi_master_set_devdata(master, &master[1]);
David Brownell8ae12a02006-01-08 13:34:19 -0800454
455 return master;
456}
457EXPORT_SYMBOL_GPL(spi_alloc_master);
458
459/**
460 * spi_register_master - register SPI master controller
461 * @master: initialized master, originally from spi_alloc_master()
David Brownell33e34dc2007-05-08 00:32:21 -0700462 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800463 *
464 * SPI master controllers connect to their drivers using some non-SPI bus,
465 * such as the platform bus. The final stage of probe() in that code
466 * includes calling spi_register_master() to hook up to this SPI bus glue.
467 *
468 * SPI controllers use board specific (often SOC specific) bus numbers,
469 * and board-specific addressing for SPI devices combines those numbers
470 * with chip select numbers. Since SPI does not directly support dynamic
471 * device identification, boards need configuration tables telling which
472 * chip is at which address.
473 *
474 * This must be called from context that can sleep. It returns zero on
475 * success, else a negative error code (dropping the master's refcount).
David Brownell0c868462006-01-08 13:34:25 -0800476 * After a successful return, the caller is responsible for calling
477 * spi_unregister_master().
David Brownell8ae12a02006-01-08 13:34:19 -0800478 */
Adrian Bunke9d5a462007-03-26 21:32:23 -0800479int spi_register_master(struct spi_master *master)
David Brownell8ae12a02006-01-08 13:34:19 -0800480{
David Brownelle44a45a2007-06-03 13:50:40 -0700481 static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
Tony Jones49dce682007-10-16 01:27:48 -0700482 struct device *dev = master->dev.parent;
David Brownell8ae12a02006-01-08 13:34:19 -0800483 int status = -ENODEV;
484 int dynamic = 0;
485
David Brownell0c868462006-01-08 13:34:25 -0800486 if (!dev)
487 return -ENODEV;
488
David Brownell082c8cb2007-07-31 00:39:45 -0700489 /* even if it's just one always-selected device, there must
490 * be at least one chipselect
491 */
492 if (master->num_chipselect == 0)
493 return -EINVAL;
494
David Brownell8ae12a02006-01-08 13:34:19 -0800495 /* convention: dynamically assigned bus IDs count down from the max */
David Brownella020ed72006-04-03 15:49:04 -0700496 if (master->bus_num < 0) {
David Brownell082c8cb2007-07-31 00:39:45 -0700497 /* FIXME switch to an IDR based scheme, something like
498 * I2C now uses, so we can't run out of "dynamic" IDs
499 */
David Brownell8ae12a02006-01-08 13:34:19 -0800500 master->bus_num = atomic_dec_return(&dyn_bus_id);
David Brownellb8852442006-01-08 13:34:23 -0800501 dynamic = 1;
David Brownell8ae12a02006-01-08 13:34:19 -0800502 }
503
504 /* register the device, then userspace will see it.
505 * registration fails if the bus ID is in use.
506 */
Tony Jones49dce682007-10-16 01:27:48 -0700507 snprintf(master->dev.bus_id, sizeof master->dev.bus_id,
David Brownell8ae12a02006-01-08 13:34:19 -0800508 "spi%u", master->bus_num);
Tony Jones49dce682007-10-16 01:27:48 -0700509 status = device_add(&master->dev);
David Brownellb8852442006-01-08 13:34:23 -0800510 if (status < 0)
David Brownell8ae12a02006-01-08 13:34:19 -0800511 goto done;
Tony Jones49dce682007-10-16 01:27:48 -0700512 dev_dbg(dev, "registered master %s%s\n", master->dev.bus_id,
David Brownell8ae12a02006-01-08 13:34:19 -0800513 dynamic ? " (dynamic)" : "");
514
515 /* populate children from any spi device tables */
516 scan_boardinfo(master);
517 status = 0;
518done:
519 return status;
520}
521EXPORT_SYMBOL_GPL(spi_register_master);
522
523
Atsushi Nemoto350d0072007-11-14 16:59:22 -0800524static int __unregister(struct device *dev, void *master_dev)
David Brownell8ae12a02006-01-08 13:34:19 -0800525{
526 /* note: before about 2.6.14-rc1 this would corrupt memory: */
Atsushi Nemoto350d0072007-11-14 16:59:22 -0800527 if (dev != master_dev)
528 spi_unregister_device(to_spi_device(dev));
David Brownell8ae12a02006-01-08 13:34:19 -0800529 return 0;
530}
531
532/**
533 * spi_unregister_master - unregister SPI master controller
534 * @master: the master being unregistered
David Brownell33e34dc2007-05-08 00:32:21 -0700535 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800536 *
537 * This call is used only by SPI master controller drivers, which are the
538 * only ones directly touching chip registers.
539 *
540 * This must be called from context that can sleep.
541 */
542void spi_unregister_master(struct spi_master *master)
543{
Jeff Garzik89fc9a12006-12-06 20:35:35 -0800544 int dummy;
545
Atsushi Nemoto350d0072007-11-14 16:59:22 -0800546 dummy = device_for_each_child(master->dev.parent, &master->dev,
547 __unregister);
Tony Jones49dce682007-10-16 01:27:48 -0700548 device_unregister(&master->dev);
David Brownell8ae12a02006-01-08 13:34:19 -0800549}
550EXPORT_SYMBOL_GPL(spi_unregister_master);
551
Dave Young5ed2c832008-01-22 15:14:18 +0800552static int __spi_master_match(struct device *dev, void *data)
553{
554 struct spi_master *m;
555 u16 *bus_num = data;
556
557 m = container_of(dev, struct spi_master, dev);
558 return m->bus_num == *bus_num;
559}
560
David Brownell8ae12a02006-01-08 13:34:19 -0800561/**
562 * spi_busnum_to_master - look up master associated with bus_num
563 * @bus_num: the master's bus number
David Brownell33e34dc2007-05-08 00:32:21 -0700564 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800565 *
566 * This call may be used with devices that are registered after
567 * arch init time. It returns a refcounted pointer to the relevant
568 * spi_master (which the caller must release), or NULL if there is
569 * no such master registered.
570 */
571struct spi_master *spi_busnum_to_master(u16 bus_num)
572{
Tony Jones49dce682007-10-16 01:27:48 -0700573 struct device *dev;
Atsushi Nemoto1e9a51d2007-01-26 00:56:54 -0800574 struct spi_master *master = NULL;
David Brownell8ae12a02006-01-08 13:34:19 -0800575
Greg Kroah-Hartman695794a2008-05-22 17:21:08 -0400576 dev = class_find_device(&spi_master_class, NULL, &bus_num,
Dave Young5ed2c832008-01-22 15:14:18 +0800577 __spi_master_match);
578 if (dev)
579 master = container_of(dev, struct spi_master, dev);
580 /* reference got in class_find_device */
Atsushi Nemoto1e9a51d2007-01-26 00:56:54 -0800581 return master;
David Brownell8ae12a02006-01-08 13:34:19 -0800582}
583EXPORT_SYMBOL_GPL(spi_busnum_to_master);
584
585
586/*-------------------------------------------------------------------------*/
587
Andrew Morton5d870c82006-01-11 11:23:49 -0800588static void spi_complete(void *arg)
589{
590 complete(arg);
591}
592
David Brownell8ae12a02006-01-08 13:34:19 -0800593/**
594 * spi_sync - blocking/synchronous SPI data transfers
595 * @spi: device with which data will be exchanged
596 * @message: describes the data transfers
David Brownell33e34dc2007-05-08 00:32:21 -0700597 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800598 *
599 * This call may only be used from a context that may sleep. The sleep
600 * is non-interruptible, and has no timeout. Low-overhead controller
601 * drivers may DMA directly into and out of the message buffers.
602 *
603 * Note that the SPI device's chip select is active during the message,
604 * and then is normally disabled between messages. Drivers for some
605 * frequently-used devices may want to minimize costs of selecting a chip,
606 * by leaving it selected in anticipation that the next message will go
607 * to the same chip. (That may increase power usage.)
608 *
David Brownell0c868462006-01-08 13:34:25 -0800609 * Also, the caller is guaranteeing that the memory associated with the
610 * message will not be freed before this call returns.
611 *
Marc Pignat9b938b72007-12-04 23:45:10 -0800612 * It returns zero on success, else a negative error code.
David Brownell8ae12a02006-01-08 13:34:19 -0800613 */
614int spi_sync(struct spi_device *spi, struct spi_message *message)
615{
Ingo Molnar60be6b92006-07-03 00:25:26 -0700616 DECLARE_COMPLETION_ONSTACK(done);
David Brownell8ae12a02006-01-08 13:34:19 -0800617 int status;
618
Andrew Morton5d870c82006-01-11 11:23:49 -0800619 message->complete = spi_complete;
David Brownell8ae12a02006-01-08 13:34:19 -0800620 message->context = &done;
621 status = spi_async(spi, message);
Marc Pignat9b938b72007-12-04 23:45:10 -0800622 if (status == 0) {
David Brownell8ae12a02006-01-08 13:34:19 -0800623 wait_for_completion(&done);
Marc Pignat9b938b72007-12-04 23:45:10 -0800624 status = message->status;
625 }
David Brownell8ae12a02006-01-08 13:34:19 -0800626 message->context = NULL;
627 return status;
628}
629EXPORT_SYMBOL_GPL(spi_sync);
630
David Brownella9948b62006-04-02 10:37:40 -0800631/* portable code must never pass more than 32 bytes */
632#define SPI_BUFSIZ max(32,SMP_CACHE_BYTES)
David Brownell8ae12a02006-01-08 13:34:19 -0800633
634static u8 *buf;
635
636/**
637 * spi_write_then_read - SPI synchronous write followed by read
638 * @spi: device with which data will be exchanged
639 * @txbuf: data to be written (need not be dma-safe)
640 * @n_tx: size of txbuf, in bytes
641 * @rxbuf: buffer into which data will be read
642 * @n_rx: size of rxbuf, in bytes (need not be dma-safe)
David Brownell33e34dc2007-05-08 00:32:21 -0700643 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800644 *
645 * This performs a half duplex MicroWire style transaction with the
646 * device, sending txbuf and then reading rxbuf. The return value
647 * is zero for success, else a negative errno status code.
David Brownellb8852442006-01-08 13:34:23 -0800648 * This call may only be used from a context that may sleep.
David Brownell8ae12a02006-01-08 13:34:19 -0800649 *
David Brownell0c868462006-01-08 13:34:25 -0800650 * Parameters to this routine are always copied using a small buffer;
David Brownell33e34dc2007-05-08 00:32:21 -0700651 * portable code should never use this for more than 32 bytes.
652 * Performance-sensitive or bulk transfer code should instead use
David Brownell0c868462006-01-08 13:34:25 -0800653 * spi_{async,sync}() calls with dma-safe buffers.
David Brownell8ae12a02006-01-08 13:34:19 -0800654 */
655int spi_write_then_read(struct spi_device *spi,
656 const u8 *txbuf, unsigned n_tx,
657 u8 *rxbuf, unsigned n_rx)
658{
David Brownell068f4072007-12-04 23:45:09 -0800659 static DEFINE_MUTEX(lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800660
661 int status;
662 struct spi_message message;
Vernon Sauderf9b90e32008-10-15 22:02:40 -0700663 struct spi_transfer x;
David Brownell8ae12a02006-01-08 13:34:19 -0800664 u8 *local_buf;
665
666 /* Use preallocated DMA-safe buffer. We can't avoid copying here,
667 * (as a pure convenience thing), but we can keep heap costs
668 * out of the hot path ...
669 */
670 if ((n_tx + n_rx) > SPI_BUFSIZ)
671 return -EINVAL;
672
Vitaly Wool8275c642006-01-08 13:34:28 -0800673 spi_message_init(&message);
Vernon Sauderf9b90e32008-10-15 22:02:40 -0700674 memset(&x, 0, sizeof x);
675 x.len = n_tx + n_rx;
676 spi_message_add_tail(&x, &message);
Vitaly Wool8275c642006-01-08 13:34:28 -0800677
David Brownell8ae12a02006-01-08 13:34:19 -0800678 /* ... unless someone else is using the pre-allocated buffer */
David Brownell068f4072007-12-04 23:45:09 -0800679 if (!mutex_trylock(&lock)) {
David Brownell8ae12a02006-01-08 13:34:19 -0800680 local_buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
681 if (!local_buf)
682 return -ENOMEM;
683 } else
684 local_buf = buf;
685
David Brownell8ae12a02006-01-08 13:34:19 -0800686 memcpy(local_buf, txbuf, n_tx);
Vernon Sauderf9b90e32008-10-15 22:02:40 -0700687 x.tx_buf = local_buf;
688 x.rx_buf = local_buf;
David Brownell8ae12a02006-01-08 13:34:19 -0800689
690 /* do the i/o */
David Brownell8ae12a02006-01-08 13:34:19 -0800691 status = spi_sync(spi, &message);
Marc Pignat9b938b72007-12-04 23:45:10 -0800692 if (status == 0)
Vernon Sauderf9b90e32008-10-15 22:02:40 -0700693 memcpy(rxbuf, x.rx_buf + n_tx, n_rx);
David Brownell8ae12a02006-01-08 13:34:19 -0800694
Vernon Sauderf9b90e32008-10-15 22:02:40 -0700695 if (x.tx_buf == buf)
David Brownell068f4072007-12-04 23:45:09 -0800696 mutex_unlock(&lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800697 else
698 kfree(local_buf);
699
700 return status;
701}
702EXPORT_SYMBOL_GPL(spi_write_then_read);
703
704/*-------------------------------------------------------------------------*/
705
706static int __init spi_init(void)
707{
David Brownellb8852442006-01-08 13:34:23 -0800708 int status;
David Brownell8ae12a02006-01-08 13:34:19 -0800709
Christoph Lametere94b1762006-12-06 20:33:17 -0800710 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
David Brownellb8852442006-01-08 13:34:23 -0800711 if (!buf) {
712 status = -ENOMEM;
713 goto err0;
714 }
715
716 status = bus_register(&spi_bus_type);
717 if (status < 0)
718 goto err1;
719
720 status = class_register(&spi_master_class);
721 if (status < 0)
722 goto err2;
David Brownell8ae12a02006-01-08 13:34:19 -0800723 return 0;
David Brownellb8852442006-01-08 13:34:23 -0800724
725err2:
726 bus_unregister(&spi_bus_type);
727err1:
728 kfree(buf);
729 buf = NULL;
730err0:
731 return status;
David Brownell8ae12a02006-01-08 13:34:19 -0800732}
David Brownellb8852442006-01-08 13:34:23 -0800733
David Brownell8ae12a02006-01-08 13:34:19 -0800734/* board_info is normally registered in arch_initcall(),
735 * but even essential drivers wait till later
David Brownellb8852442006-01-08 13:34:23 -0800736 *
737 * REVISIT only boardinfo really needs static linking. the rest (device and
738 * driver registration) _could_ be dynamically linked (modular) ... costs
739 * include needing to have boardinfo data structures be much more public.
David Brownell8ae12a02006-01-08 13:34:19 -0800740 */
David Brownell673c0c02008-10-15 22:02:46 -0700741postcore_initcall(spi_init);
David Brownell8ae12a02006-01-08 13:34:19 -0800742