blob: 8eba98c8ed1e0727bb200f58be39d3831ab30b26 [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
Kay Sievers35f74fc2009-01-06 10:44:37 -080050 return sprintf(buf, "%s\n", spi->modalias);
David Brownell8ae12a02006-01-08 13:34:19 -080051}
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
Kay Sievers35f74fc2009-01-06 10:44:37 -080066 return strcmp(spi->modalias, drv->name) == 0;
David Brownell8ae12a02006-01-08 13:34:19 -080067}
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 */
Kay Sievers35f74fc2009-01-06 10:44:37 -0800246 dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
Grant Likelydc87c982008-05-15 16:50:22 -0600247 spi->chip_select);
248
David Brownelle48880e2008-08-15 00:40:44 -0700249
250 /* We need to make sure there's no other device with this
251 * chipselect **BEFORE** we call setup(), else we'll trash
252 * its configuration. Lock against concurrent add() calls.
253 */
254 mutex_lock(&spi_add_lock);
255
Kay Sievers35f74fc2009-01-06 10:44:37 -0800256 if (bus_find_device_by_name(&spi_bus_type, NULL, dev_name(&spi->dev))
David Brownelle48880e2008-08-15 00:40:44 -0700257 != NULL) {
258 dev_err(dev, "chipselect %d already in use\n",
259 spi->chip_select);
260 status = -EBUSY;
261 goto done;
262 }
263
264 /* Drivers may modify this initial i/o setup, but will
265 * normally rely on the device being setup. Devices
266 * using SPI_CS_HIGH can't coexist well otherwise...
267 */
Grant Likelydc87c982008-05-15 16:50:22 -0600268 status = spi->master->setup(spi);
269 if (status < 0) {
270 dev_err(dev, "can't %s %s, status %d\n",
Kay Sievers35f74fc2009-01-06 10:44:37 -0800271 "setup", dev_name(&spi->dev), status);
David Brownelle48880e2008-08-15 00:40:44 -0700272 goto done;
Grant Likelydc87c982008-05-15 16:50:22 -0600273 }
274
David Brownelle48880e2008-08-15 00:40:44 -0700275 /* Device may be bound to an active driver when this returns */
Grant Likelydc87c982008-05-15 16:50:22 -0600276 status = device_add(&spi->dev);
David Brownelle48880e2008-08-15 00:40:44 -0700277 if (status < 0)
Grant Likelydc87c982008-05-15 16:50:22 -0600278 dev_err(dev, "can't %s %s, status %d\n",
Kay Sievers35f74fc2009-01-06 10:44:37 -0800279 "add", dev_name(&spi->dev), status);
David Brownelle48880e2008-08-15 00:40:44 -0700280 else
Kay Sievers35f74fc2009-01-06 10:44:37 -0800281 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
Grant Likelydc87c982008-05-15 16:50:22 -0600282
David Brownelle48880e2008-08-15 00:40:44 -0700283done:
284 mutex_unlock(&spi_add_lock);
285 return status;
Grant Likelydc87c982008-05-15 16:50:22 -0600286}
287EXPORT_SYMBOL_GPL(spi_add_device);
David Brownell8ae12a02006-01-08 13:34:19 -0800288
David Brownell33e34dc2007-05-08 00:32:21 -0700289/**
290 * spi_new_device - instantiate one new SPI device
291 * @master: Controller to which device is connected
292 * @chip: Describes the SPI device
293 * Context: can sleep
294 *
295 * On typical mainboards, this is purely internal; and it's not needed
David Brownell8ae12a02006-01-08 13:34:19 -0800296 * after board init creates the hard-wired devices. Some development
297 * platforms may not be able to use spi_register_board_info though, and
298 * this is exported so that for example a USB or parport based adapter
299 * driver could add devices (which it would learn about out-of-band).
David Brownell082c8cb2007-07-31 00:39:45 -0700300 *
301 * Returns the new device, or NULL.
David Brownell8ae12a02006-01-08 13:34:19 -0800302 */
Adrian Bunke9d5a462007-03-26 21:32:23 -0800303struct spi_device *spi_new_device(struct spi_master *master,
304 struct spi_board_info *chip)
David Brownell8ae12a02006-01-08 13:34:19 -0800305{
306 struct spi_device *proxy;
David Brownell8ae12a02006-01-08 13:34:19 -0800307 int status;
308
David Brownell082c8cb2007-07-31 00:39:45 -0700309 /* NOTE: caller did any chip->bus_num checks necessary.
310 *
311 * Also, unless we change the return value convention to use
312 * error-or-pointer (not NULL-or-pointer), troubleshootability
313 * suggests syslogged diagnostics are best here (ugh).
314 */
315
Grant Likelydc87c982008-05-15 16:50:22 -0600316 proxy = spi_alloc_device(master);
317 if (!proxy)
David Brownell8ae12a02006-01-08 13:34:19 -0800318 return NULL;
319
Grant Likely102eb972008-07-23 21:29:55 -0700320 WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
321
David Brownell8ae12a02006-01-08 13:34:19 -0800322 proxy->chip_select = chip->chip_select;
323 proxy->max_speed_hz = chip->max_speed_hz;
David Brownell980a01c2006-06-28 07:47:15 -0700324 proxy->mode = chip->mode;
David Brownell8ae12a02006-01-08 13:34:19 -0800325 proxy->irq = chip->irq;
Grant Likely102eb972008-07-23 21:29:55 -0700326 strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
David Brownell8ae12a02006-01-08 13:34:19 -0800327 proxy->dev.platform_data = (void *) chip->platform_data;
328 proxy->controller_data = chip->controller_data;
329 proxy->controller_state = NULL;
David Brownell8ae12a02006-01-08 13:34:19 -0800330
Grant Likelydc87c982008-05-15 16:50:22 -0600331 status = spi_add_device(proxy);
David Brownell8ae12a02006-01-08 13:34:19 -0800332 if (status < 0) {
Grant Likelydc87c982008-05-15 16:50:22 -0600333 spi_dev_put(proxy);
334 return NULL;
David Brownell8ae12a02006-01-08 13:34:19 -0800335 }
336
David Brownell8ae12a02006-01-08 13:34:19 -0800337 return proxy;
338}
339EXPORT_SYMBOL_GPL(spi_new_device);
340
David Brownell33e34dc2007-05-08 00:32:21 -0700341/**
342 * spi_register_board_info - register SPI devices for a given board
343 * @info: array of chip descriptors
344 * @n: how many descriptors are provided
345 * Context: can sleep
346 *
David Brownell8ae12a02006-01-08 13:34:19 -0800347 * Board-specific early init code calls this (probably during arch_initcall)
348 * with segments of the SPI device table. Any device nodes are created later,
349 * after the relevant parent SPI controller (bus_num) is defined. We keep
350 * this table of devices forever, so that reloading a controller driver will
351 * not make Linux forget about these hard-wired devices.
352 *
353 * Other code can also call this, e.g. a particular add-on board might provide
354 * SPI devices through its expansion connector, so code initializing that board
355 * would naturally declare its SPI devices.
356 *
357 * The board info passed can safely be __initdata ... but be careful of
358 * any embedded pointers (platform_data, etc), they're copied as-is.
359 */
360int __init
361spi_register_board_info(struct spi_board_info const *info, unsigned n)
362{
363 struct boardinfo *bi;
364
David Brownellb8852442006-01-08 13:34:23 -0800365 bi = kmalloc(sizeof(*bi) + n * sizeof *info, GFP_KERNEL);
David Brownell8ae12a02006-01-08 13:34:19 -0800366 if (!bi)
367 return -ENOMEM;
368 bi->n_board_info = n;
David Brownellb8852442006-01-08 13:34:23 -0800369 memcpy(bi->board_info, info, n * sizeof *info);
David Brownell8ae12a02006-01-08 13:34:19 -0800370
Matthias Kaehlcke94040822007-07-17 04:04:16 -0700371 mutex_lock(&board_lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800372 list_add_tail(&bi->list, &board_list);
Matthias Kaehlcke94040822007-07-17 04:04:16 -0700373 mutex_unlock(&board_lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800374 return 0;
375}
David Brownell8ae12a02006-01-08 13:34:19 -0800376
377/* FIXME someone should add support for a __setup("spi", ...) that
378 * creates board info from kernel command lines
379 */
380
Adrian Bunk149a6502007-07-21 04:37:52 -0700381static void scan_boardinfo(struct spi_master *master)
David Brownell8ae12a02006-01-08 13:34:19 -0800382{
383 struct boardinfo *bi;
David Brownell8ae12a02006-01-08 13:34:19 -0800384
Matthias Kaehlcke94040822007-07-17 04:04:16 -0700385 mutex_lock(&board_lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800386 list_for_each_entry(bi, &board_list, list) {
387 struct spi_board_info *chip = bi->board_info;
388 unsigned n;
389
390 for (n = bi->n_board_info; n > 0; n--, chip++) {
391 if (chip->bus_num != master->bus_num)
392 continue;
David Brownell082c8cb2007-07-31 00:39:45 -0700393 /* NOTE: this relies on spi_new_device to
394 * issue diagnostics when given bogus inputs
David Brownell8ae12a02006-01-08 13:34:19 -0800395 */
David Brownell8ae12a02006-01-08 13:34:19 -0800396 (void) spi_new_device(master, chip);
397 }
398 }
Matthias Kaehlcke94040822007-07-17 04:04:16 -0700399 mutex_unlock(&board_lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800400}
401
402/*-------------------------------------------------------------------------*/
403
Tony Jones49dce682007-10-16 01:27:48 -0700404static void spi_master_release(struct device *dev)
David Brownell8ae12a02006-01-08 13:34:19 -0800405{
406 struct spi_master *master;
407
Tony Jones49dce682007-10-16 01:27:48 -0700408 master = container_of(dev, struct spi_master, dev);
David Brownell8ae12a02006-01-08 13:34:19 -0800409 kfree(master);
410}
411
412static struct class spi_master_class = {
413 .name = "spi_master",
414 .owner = THIS_MODULE,
Tony Jones49dce682007-10-16 01:27:48 -0700415 .dev_release = spi_master_release,
David Brownell8ae12a02006-01-08 13:34:19 -0800416};
417
418
419/**
420 * spi_alloc_master - allocate SPI master controller
421 * @dev: the controller, possibly using the platform_bus
David Brownell33e34dc2007-05-08 00:32:21 -0700422 * @size: how much zeroed driver-private data to allocate; the pointer to this
Tony Jones49dce682007-10-16 01:27:48 -0700423 * memory is in the driver_data field of the returned device,
David Brownell0c868462006-01-08 13:34:25 -0800424 * accessible with spi_master_get_devdata().
David Brownell33e34dc2007-05-08 00:32:21 -0700425 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800426 *
427 * This call is used only by SPI master controller drivers, which are the
428 * only ones directly touching chip registers. It's how they allocate
dmitry pervushinba1a0512006-05-20 15:00:14 -0700429 * an spi_master structure, prior to calling spi_register_master().
David Brownell8ae12a02006-01-08 13:34:19 -0800430 *
431 * This must be called from context that can sleep. It returns the SPI
432 * master structure on success, else NULL.
433 *
434 * The caller is responsible for assigning the bus number and initializing
dmitry pervushinba1a0512006-05-20 15:00:14 -0700435 * the master's methods before calling spi_register_master(); and (after errors
David Brownell0c868462006-01-08 13:34:25 -0800436 * adding the device) calling spi_master_put() to prevent a memory leak.
David Brownell8ae12a02006-01-08 13:34:19 -0800437 */
Adrian Bunke9d5a462007-03-26 21:32:23 -0800438struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
David Brownell8ae12a02006-01-08 13:34:19 -0800439{
440 struct spi_master *master;
441
David Brownell0c868462006-01-08 13:34:25 -0800442 if (!dev)
443 return NULL;
444
Christoph Lametere94b1762006-12-06 20:33:17 -0800445 master = kzalloc(size + sizeof *master, GFP_KERNEL);
David Brownell8ae12a02006-01-08 13:34:19 -0800446 if (!master)
447 return NULL;
448
Tony Jones49dce682007-10-16 01:27:48 -0700449 device_initialize(&master->dev);
450 master->dev.class = &spi_master_class;
451 master->dev.parent = get_device(dev);
David Brownell0c868462006-01-08 13:34:25 -0800452 spi_master_set_devdata(master, &master[1]);
David Brownell8ae12a02006-01-08 13:34:19 -0800453
454 return master;
455}
456EXPORT_SYMBOL_GPL(spi_alloc_master);
457
458/**
459 * spi_register_master - register SPI master controller
460 * @master: initialized master, originally from spi_alloc_master()
David Brownell33e34dc2007-05-08 00:32:21 -0700461 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800462 *
463 * SPI master controllers connect to their drivers using some non-SPI bus,
464 * such as the platform bus. The final stage of probe() in that code
465 * includes calling spi_register_master() to hook up to this SPI bus glue.
466 *
467 * SPI controllers use board specific (often SOC specific) bus numbers,
468 * and board-specific addressing for SPI devices combines those numbers
469 * with chip select numbers. Since SPI does not directly support dynamic
470 * device identification, boards need configuration tables telling which
471 * chip is at which address.
472 *
473 * This must be called from context that can sleep. It returns zero on
474 * success, else a negative error code (dropping the master's refcount).
David Brownell0c868462006-01-08 13:34:25 -0800475 * After a successful return, the caller is responsible for calling
476 * spi_unregister_master().
David Brownell8ae12a02006-01-08 13:34:19 -0800477 */
Adrian Bunke9d5a462007-03-26 21:32:23 -0800478int spi_register_master(struct spi_master *master)
David Brownell8ae12a02006-01-08 13:34:19 -0800479{
David Brownelle44a45a2007-06-03 13:50:40 -0700480 static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
Tony Jones49dce682007-10-16 01:27:48 -0700481 struct device *dev = master->dev.parent;
David Brownell8ae12a02006-01-08 13:34:19 -0800482 int status = -ENODEV;
483 int dynamic = 0;
484
David Brownell0c868462006-01-08 13:34:25 -0800485 if (!dev)
486 return -ENODEV;
487
David Brownell082c8cb2007-07-31 00:39:45 -0700488 /* even if it's just one always-selected device, there must
489 * be at least one chipselect
490 */
491 if (master->num_chipselect == 0)
492 return -EINVAL;
493
David Brownell8ae12a02006-01-08 13:34:19 -0800494 /* convention: dynamically assigned bus IDs count down from the max */
David Brownella020ed72006-04-03 15:49:04 -0700495 if (master->bus_num < 0) {
David Brownell082c8cb2007-07-31 00:39:45 -0700496 /* FIXME switch to an IDR based scheme, something like
497 * I2C now uses, so we can't run out of "dynamic" IDs
498 */
David Brownell8ae12a02006-01-08 13:34:19 -0800499 master->bus_num = atomic_dec_return(&dyn_bus_id);
David Brownellb8852442006-01-08 13:34:23 -0800500 dynamic = 1;
David Brownell8ae12a02006-01-08 13:34:19 -0800501 }
502
503 /* register the device, then userspace will see it.
504 * registration fails if the bus ID is in use.
505 */
Kay Sievers35f74fc2009-01-06 10:44:37 -0800506 dev_set_name(&master->dev, "spi%u", master->bus_num);
Tony Jones49dce682007-10-16 01:27:48 -0700507 status = device_add(&master->dev);
David Brownellb8852442006-01-08 13:34:23 -0800508 if (status < 0)
David Brownell8ae12a02006-01-08 13:34:19 -0800509 goto done;
Kay Sievers35f74fc2009-01-06 10:44:37 -0800510 dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
David Brownell8ae12a02006-01-08 13:34:19 -0800511 dynamic ? " (dynamic)" : "");
512
513 /* populate children from any spi device tables */
514 scan_boardinfo(master);
515 status = 0;
516done:
517 return status;
518}
519EXPORT_SYMBOL_GPL(spi_register_master);
520
521
Atsushi Nemoto350d0072007-11-14 16:59:22 -0800522static int __unregister(struct device *dev, void *master_dev)
David Brownell8ae12a02006-01-08 13:34:19 -0800523{
524 /* note: before about 2.6.14-rc1 this would corrupt memory: */
Atsushi Nemoto350d0072007-11-14 16:59:22 -0800525 if (dev != master_dev)
526 spi_unregister_device(to_spi_device(dev));
David Brownell8ae12a02006-01-08 13:34:19 -0800527 return 0;
528}
529
530/**
531 * spi_unregister_master - unregister SPI master controller
532 * @master: the master being unregistered
David Brownell33e34dc2007-05-08 00:32:21 -0700533 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800534 *
535 * This call is used only by SPI master controller drivers, which are the
536 * only ones directly touching chip registers.
537 *
538 * This must be called from context that can sleep.
539 */
540void spi_unregister_master(struct spi_master *master)
541{
Jeff Garzik89fc9a12006-12-06 20:35:35 -0800542 int dummy;
543
Atsushi Nemoto350d0072007-11-14 16:59:22 -0800544 dummy = device_for_each_child(master->dev.parent, &master->dev,
545 __unregister);
Tony Jones49dce682007-10-16 01:27:48 -0700546 device_unregister(&master->dev);
David Brownell8ae12a02006-01-08 13:34:19 -0800547}
548EXPORT_SYMBOL_GPL(spi_unregister_master);
549
Dave Young5ed2c832008-01-22 15:14:18 +0800550static int __spi_master_match(struct device *dev, void *data)
551{
552 struct spi_master *m;
553 u16 *bus_num = data;
554
555 m = container_of(dev, struct spi_master, dev);
556 return m->bus_num == *bus_num;
557}
558
David Brownell8ae12a02006-01-08 13:34:19 -0800559/**
560 * spi_busnum_to_master - look up master associated with bus_num
561 * @bus_num: the master's bus number
David Brownell33e34dc2007-05-08 00:32:21 -0700562 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800563 *
564 * This call may be used with devices that are registered after
565 * arch init time. It returns a refcounted pointer to the relevant
566 * spi_master (which the caller must release), or NULL if there is
567 * no such master registered.
568 */
569struct spi_master *spi_busnum_to_master(u16 bus_num)
570{
Tony Jones49dce682007-10-16 01:27:48 -0700571 struct device *dev;
Atsushi Nemoto1e9a51d2007-01-26 00:56:54 -0800572 struct spi_master *master = NULL;
David Brownell8ae12a02006-01-08 13:34:19 -0800573
Greg Kroah-Hartman695794a2008-05-22 17:21:08 -0400574 dev = class_find_device(&spi_master_class, NULL, &bus_num,
Dave Young5ed2c832008-01-22 15:14:18 +0800575 __spi_master_match);
576 if (dev)
577 master = container_of(dev, struct spi_master, dev);
578 /* reference got in class_find_device */
Atsushi Nemoto1e9a51d2007-01-26 00:56:54 -0800579 return master;
David Brownell8ae12a02006-01-08 13:34:19 -0800580}
581EXPORT_SYMBOL_GPL(spi_busnum_to_master);
582
583
584/*-------------------------------------------------------------------------*/
585
Andrew Morton5d870c82006-01-11 11:23:49 -0800586static void spi_complete(void *arg)
587{
588 complete(arg);
589}
590
David Brownell8ae12a02006-01-08 13:34:19 -0800591/**
592 * spi_sync - blocking/synchronous SPI data transfers
593 * @spi: device with which data will be exchanged
594 * @message: describes the data transfers
David Brownell33e34dc2007-05-08 00:32:21 -0700595 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800596 *
597 * This call may only be used from a context that may sleep. The sleep
598 * is non-interruptible, and has no timeout. Low-overhead controller
599 * drivers may DMA directly into and out of the message buffers.
600 *
601 * Note that the SPI device's chip select is active during the message,
602 * and then is normally disabled between messages. Drivers for some
603 * frequently-used devices may want to minimize costs of selecting a chip,
604 * by leaving it selected in anticipation that the next message will go
605 * to the same chip. (That may increase power usage.)
606 *
David Brownell0c868462006-01-08 13:34:25 -0800607 * Also, the caller is guaranteeing that the memory associated with the
608 * message will not be freed before this call returns.
609 *
Marc Pignat9b938b72007-12-04 23:45:10 -0800610 * It returns zero on success, else a negative error code.
David Brownell8ae12a02006-01-08 13:34:19 -0800611 */
612int spi_sync(struct spi_device *spi, struct spi_message *message)
613{
Ingo Molnar60be6b92006-07-03 00:25:26 -0700614 DECLARE_COMPLETION_ONSTACK(done);
David Brownell8ae12a02006-01-08 13:34:19 -0800615 int status;
616
Andrew Morton5d870c82006-01-11 11:23:49 -0800617 message->complete = spi_complete;
David Brownell8ae12a02006-01-08 13:34:19 -0800618 message->context = &done;
619 status = spi_async(spi, message);
Marc Pignat9b938b72007-12-04 23:45:10 -0800620 if (status == 0) {
David Brownell8ae12a02006-01-08 13:34:19 -0800621 wait_for_completion(&done);
Marc Pignat9b938b72007-12-04 23:45:10 -0800622 status = message->status;
623 }
David Brownell8ae12a02006-01-08 13:34:19 -0800624 message->context = NULL;
625 return status;
626}
627EXPORT_SYMBOL_GPL(spi_sync);
628
David Brownella9948b62006-04-02 10:37:40 -0800629/* portable code must never pass more than 32 bytes */
630#define SPI_BUFSIZ max(32,SMP_CACHE_BYTES)
David Brownell8ae12a02006-01-08 13:34:19 -0800631
632static u8 *buf;
633
634/**
635 * spi_write_then_read - SPI synchronous write followed by read
636 * @spi: device with which data will be exchanged
637 * @txbuf: data to be written (need not be dma-safe)
638 * @n_tx: size of txbuf, in bytes
639 * @rxbuf: buffer into which data will be read
640 * @n_rx: size of rxbuf, in bytes (need not be dma-safe)
David Brownell33e34dc2007-05-08 00:32:21 -0700641 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800642 *
643 * This performs a half duplex MicroWire style transaction with the
644 * device, sending txbuf and then reading rxbuf. The return value
645 * is zero for success, else a negative errno status code.
David Brownellb8852442006-01-08 13:34:23 -0800646 * This call may only be used from a context that may sleep.
David Brownell8ae12a02006-01-08 13:34:19 -0800647 *
David Brownell0c868462006-01-08 13:34:25 -0800648 * Parameters to this routine are always copied using a small buffer;
David Brownell33e34dc2007-05-08 00:32:21 -0700649 * portable code should never use this for more than 32 bytes.
650 * Performance-sensitive or bulk transfer code should instead use
David Brownell0c868462006-01-08 13:34:25 -0800651 * spi_{async,sync}() calls with dma-safe buffers.
David Brownell8ae12a02006-01-08 13:34:19 -0800652 */
653int spi_write_then_read(struct spi_device *spi,
654 const u8 *txbuf, unsigned n_tx,
655 u8 *rxbuf, unsigned n_rx)
656{
David Brownell068f4072007-12-04 23:45:09 -0800657 static DEFINE_MUTEX(lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800658
659 int status;
660 struct spi_message message;
David Brownellbdff5492009-04-13 14:39:57 -0700661 struct spi_transfer x[2];
David Brownell8ae12a02006-01-08 13:34:19 -0800662 u8 *local_buf;
663
664 /* Use preallocated DMA-safe buffer. We can't avoid copying here,
665 * (as a pure convenience thing), but we can keep heap costs
666 * out of the hot path ...
667 */
668 if ((n_tx + n_rx) > SPI_BUFSIZ)
669 return -EINVAL;
670
Vitaly Wool8275c642006-01-08 13:34:28 -0800671 spi_message_init(&message);
David Brownellbdff5492009-04-13 14:39:57 -0700672 memset(x, 0, sizeof x);
673 if (n_tx) {
674 x[0].len = n_tx;
675 spi_message_add_tail(&x[0], &message);
676 }
677 if (n_rx) {
678 x[1].len = n_rx;
679 spi_message_add_tail(&x[1], &message);
680 }
Vitaly Wool8275c642006-01-08 13:34:28 -0800681
David Brownell8ae12a02006-01-08 13:34:19 -0800682 /* ... unless someone else is using the pre-allocated buffer */
David Brownell068f4072007-12-04 23:45:09 -0800683 if (!mutex_trylock(&lock)) {
David Brownell8ae12a02006-01-08 13:34:19 -0800684 local_buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
685 if (!local_buf)
686 return -ENOMEM;
687 } else
688 local_buf = buf;
689
David Brownell8ae12a02006-01-08 13:34:19 -0800690 memcpy(local_buf, txbuf, n_tx);
David Brownellbdff5492009-04-13 14:39:57 -0700691 x[0].tx_buf = local_buf;
692 x[1].rx_buf = local_buf + n_tx;
David Brownell8ae12a02006-01-08 13:34:19 -0800693
694 /* do the i/o */
David Brownell8ae12a02006-01-08 13:34:19 -0800695 status = spi_sync(spi, &message);
Marc Pignat9b938b72007-12-04 23:45:10 -0800696 if (status == 0)
David Brownellbdff5492009-04-13 14:39:57 -0700697 memcpy(rxbuf, x[1].rx_buf, n_rx);
David Brownell8ae12a02006-01-08 13:34:19 -0800698
David Brownellbdff5492009-04-13 14:39:57 -0700699 if (x[0].tx_buf == buf)
David Brownell068f4072007-12-04 23:45:09 -0800700 mutex_unlock(&lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800701 else
702 kfree(local_buf);
703
704 return status;
705}
706EXPORT_SYMBOL_GPL(spi_write_then_read);
707
708/*-------------------------------------------------------------------------*/
709
710static int __init spi_init(void)
711{
David Brownellb8852442006-01-08 13:34:23 -0800712 int status;
David Brownell8ae12a02006-01-08 13:34:19 -0800713
Christoph Lametere94b1762006-12-06 20:33:17 -0800714 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
David Brownellb8852442006-01-08 13:34:23 -0800715 if (!buf) {
716 status = -ENOMEM;
717 goto err0;
718 }
719
720 status = bus_register(&spi_bus_type);
721 if (status < 0)
722 goto err1;
723
724 status = class_register(&spi_master_class);
725 if (status < 0)
726 goto err2;
David Brownell8ae12a02006-01-08 13:34:19 -0800727 return 0;
David Brownellb8852442006-01-08 13:34:23 -0800728
729err2:
730 bus_unregister(&spi_bus_type);
731err1:
732 kfree(buf);
733 buf = NULL;
734err0:
735 return status;
David Brownell8ae12a02006-01-08 13:34:19 -0800736}
David Brownellb8852442006-01-08 13:34:23 -0800737
David Brownell8ae12a02006-01-08 13:34:19 -0800738/* board_info is normally registered in arch_initcall(),
739 * but even essential drivers wait till later
David Brownellb8852442006-01-08 13:34:23 -0800740 *
741 * REVISIT only boardinfo really needs static linking. the rest (device and
742 * driver registration) _could_ be dynamically linked (modular) ... costs
743 * include needing to have boardinfo data structures be much more public.
David Brownell8ae12a02006-01-08 13:34:19 -0800744 */
David Brownell673c0c02008-10-15 22:02:46 -0700745postcore_initcall(spi_init);
David Brownell8ae12a02006-01-08 13:34:19 -0800746