blob: 1ad12afc6ba0ace916c817c571b265dc49cc1398 [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
181
David Brownell33e34dc2007-05-08 00:32:21 -0700182/**
183 * spi_new_device - instantiate one new SPI device
184 * @master: Controller to which device is connected
185 * @chip: Describes the SPI device
186 * Context: can sleep
187 *
188 * On typical mainboards, this is purely internal; and it's not needed
David Brownell8ae12a02006-01-08 13:34:19 -0800189 * after board init creates the hard-wired devices. Some development
190 * platforms may not be able to use spi_register_board_info though, and
191 * this is exported so that for example a USB or parport based adapter
192 * driver could add devices (which it would learn about out-of-band).
David Brownell082c8cb2007-07-31 00:39:45 -0700193 *
194 * Returns the new device, or NULL.
David Brownell8ae12a02006-01-08 13:34:19 -0800195 */
Adrian Bunke9d5a462007-03-26 21:32:23 -0800196struct spi_device *spi_new_device(struct spi_master *master,
197 struct spi_board_info *chip)
David Brownell8ae12a02006-01-08 13:34:19 -0800198{
199 struct spi_device *proxy;
Tony Jones49dce682007-10-16 01:27:48 -0700200 struct device *dev = master->dev.parent;
David Brownell8ae12a02006-01-08 13:34:19 -0800201 int status;
202
David Brownell082c8cb2007-07-31 00:39:45 -0700203 /* NOTE: caller did any chip->bus_num checks necessary.
204 *
205 * Also, unless we change the return value convention to use
206 * error-or-pointer (not NULL-or-pointer), troubleshootability
207 * suggests syslogged diagnostics are best here (ugh).
208 */
209
210 /* Chipselects are numbered 0..max; validate. */
211 if (chip->chip_select >= master->num_chipselect) {
212 dev_err(dev, "cs%d > max %d\n",
213 chip->chip_select,
214 master->num_chipselect);
215 return NULL;
216 }
David Brownell8ae12a02006-01-08 13:34:19 -0800217
David Brownell0c868462006-01-08 13:34:25 -0800218 if (!spi_master_get(master))
David Brownell8ae12a02006-01-08 13:34:19 -0800219 return NULL;
220
221 proxy = kzalloc(sizeof *proxy, GFP_KERNEL);
222 if (!proxy) {
223 dev_err(dev, "can't alloc dev for cs%d\n",
224 chip->chip_select);
225 goto fail;
226 }
227 proxy->master = master;
228 proxy->chip_select = chip->chip_select;
229 proxy->max_speed_hz = chip->max_speed_hz;
David Brownell980a01c2006-06-28 07:47:15 -0700230 proxy->mode = chip->mode;
David Brownell8ae12a02006-01-08 13:34:19 -0800231 proxy->irq = chip->irq;
232 proxy->modalias = chip->modalias;
233
234 snprintf(proxy->dev.bus_id, sizeof proxy->dev.bus_id,
Tony Jones49dce682007-10-16 01:27:48 -0700235 "%s.%u", master->dev.bus_id,
David Brownell8ae12a02006-01-08 13:34:19 -0800236 chip->chip_select);
237 proxy->dev.parent = dev;
238 proxy->dev.bus = &spi_bus_type;
239 proxy->dev.platform_data = (void *) chip->platform_data;
240 proxy->controller_data = chip->controller_data;
241 proxy->controller_state = NULL;
242 proxy->dev.release = spidev_release;
243
David Brownell082c8cb2007-07-31 00:39:45 -0700244 /* drivers may modify this initial i/o setup */
David Brownell8ae12a02006-01-08 13:34:19 -0800245 status = master->setup(proxy);
246 if (status < 0) {
David Brownell082c8cb2007-07-31 00:39:45 -0700247 dev_err(dev, "can't %s %s, status %d\n",
David Brownell8ae12a02006-01-08 13:34:19 -0800248 "setup", proxy->dev.bus_id, status);
249 goto fail;
250 }
251
252 /* driver core catches callers that misbehave by defining
253 * devices that already exist.
254 */
255 status = device_register(&proxy->dev);
256 if (status < 0) {
David Brownell082c8cb2007-07-31 00:39:45 -0700257 dev_err(dev, "can't %s %s, status %d\n",
David Brownell8ae12a02006-01-08 13:34:19 -0800258 "add", proxy->dev.bus_id, status);
David Brownellb8852442006-01-08 13:34:23 -0800259 goto fail;
David Brownell8ae12a02006-01-08 13:34:19 -0800260 }
261 dev_dbg(dev, "registered child %s\n", proxy->dev.bus_id);
262 return proxy;
David Brownellb8852442006-01-08 13:34:23 -0800263
264fail:
David Brownell0c868462006-01-08 13:34:25 -0800265 spi_master_put(master);
David Brownellb8852442006-01-08 13:34:23 -0800266 kfree(proxy);
267 return NULL;
David Brownell8ae12a02006-01-08 13:34:19 -0800268}
269EXPORT_SYMBOL_GPL(spi_new_device);
270
David Brownell33e34dc2007-05-08 00:32:21 -0700271/**
272 * spi_register_board_info - register SPI devices for a given board
273 * @info: array of chip descriptors
274 * @n: how many descriptors are provided
275 * Context: can sleep
276 *
David Brownell8ae12a02006-01-08 13:34:19 -0800277 * Board-specific early init code calls this (probably during arch_initcall)
278 * with segments of the SPI device table. Any device nodes are created later,
279 * after the relevant parent SPI controller (bus_num) is defined. We keep
280 * this table of devices forever, so that reloading a controller driver will
281 * not make Linux forget about these hard-wired devices.
282 *
283 * Other code can also call this, e.g. a particular add-on board might provide
284 * SPI devices through its expansion connector, so code initializing that board
285 * would naturally declare its SPI devices.
286 *
287 * The board info passed can safely be __initdata ... but be careful of
288 * any embedded pointers (platform_data, etc), they're copied as-is.
289 */
290int __init
291spi_register_board_info(struct spi_board_info const *info, unsigned n)
292{
293 struct boardinfo *bi;
294
David Brownellb8852442006-01-08 13:34:23 -0800295 bi = kmalloc(sizeof(*bi) + n * sizeof *info, GFP_KERNEL);
David Brownell8ae12a02006-01-08 13:34:19 -0800296 if (!bi)
297 return -ENOMEM;
298 bi->n_board_info = n;
David Brownellb8852442006-01-08 13:34:23 -0800299 memcpy(bi->board_info, info, n * sizeof *info);
David Brownell8ae12a02006-01-08 13:34:19 -0800300
Matthias Kaehlcke94040822007-07-17 04:04:16 -0700301 mutex_lock(&board_lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800302 list_add_tail(&bi->list, &board_list);
Matthias Kaehlcke94040822007-07-17 04:04:16 -0700303 mutex_unlock(&board_lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800304 return 0;
305}
David Brownell8ae12a02006-01-08 13:34:19 -0800306
307/* FIXME someone should add support for a __setup("spi", ...) that
308 * creates board info from kernel command lines
309 */
310
Adrian Bunk149a6502007-07-21 04:37:52 -0700311static void scan_boardinfo(struct spi_master *master)
David Brownell8ae12a02006-01-08 13:34:19 -0800312{
313 struct boardinfo *bi;
David Brownell8ae12a02006-01-08 13:34:19 -0800314
Matthias Kaehlcke94040822007-07-17 04:04:16 -0700315 mutex_lock(&board_lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800316 list_for_each_entry(bi, &board_list, list) {
317 struct spi_board_info *chip = bi->board_info;
318 unsigned n;
319
320 for (n = bi->n_board_info; n > 0; n--, chip++) {
321 if (chip->bus_num != master->bus_num)
322 continue;
David Brownell082c8cb2007-07-31 00:39:45 -0700323 /* NOTE: this relies on spi_new_device to
324 * issue diagnostics when given bogus inputs
David Brownell8ae12a02006-01-08 13:34:19 -0800325 */
David Brownell8ae12a02006-01-08 13:34:19 -0800326 (void) spi_new_device(master, chip);
327 }
328 }
Matthias Kaehlcke94040822007-07-17 04:04:16 -0700329 mutex_unlock(&board_lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800330}
331
332/*-------------------------------------------------------------------------*/
333
Tony Jones49dce682007-10-16 01:27:48 -0700334static void spi_master_release(struct device *dev)
David Brownell8ae12a02006-01-08 13:34:19 -0800335{
336 struct spi_master *master;
337
Tony Jones49dce682007-10-16 01:27:48 -0700338 master = container_of(dev, struct spi_master, dev);
David Brownell8ae12a02006-01-08 13:34:19 -0800339 kfree(master);
340}
341
342static struct class spi_master_class = {
343 .name = "spi_master",
344 .owner = THIS_MODULE,
Tony Jones49dce682007-10-16 01:27:48 -0700345 .dev_release = spi_master_release,
David Brownell8ae12a02006-01-08 13:34:19 -0800346};
347
348
349/**
350 * spi_alloc_master - allocate SPI master controller
351 * @dev: the controller, possibly using the platform_bus
David Brownell33e34dc2007-05-08 00:32:21 -0700352 * @size: how much zeroed driver-private data to allocate; the pointer to this
Tony Jones49dce682007-10-16 01:27:48 -0700353 * memory is in the driver_data field of the returned device,
David Brownell0c868462006-01-08 13:34:25 -0800354 * accessible with spi_master_get_devdata().
David Brownell33e34dc2007-05-08 00:32:21 -0700355 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800356 *
357 * This call is used only by SPI master controller drivers, which are the
358 * only ones directly touching chip registers. It's how they allocate
dmitry pervushinba1a0512006-05-20 15:00:14 -0700359 * an spi_master structure, prior to calling spi_register_master().
David Brownell8ae12a02006-01-08 13:34:19 -0800360 *
361 * This must be called from context that can sleep. It returns the SPI
362 * master structure on success, else NULL.
363 *
364 * The caller is responsible for assigning the bus number and initializing
dmitry pervushinba1a0512006-05-20 15:00:14 -0700365 * the master's methods before calling spi_register_master(); and (after errors
David Brownell0c868462006-01-08 13:34:25 -0800366 * adding the device) calling spi_master_put() to prevent a memory leak.
David Brownell8ae12a02006-01-08 13:34:19 -0800367 */
Adrian Bunke9d5a462007-03-26 21:32:23 -0800368struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
David Brownell8ae12a02006-01-08 13:34:19 -0800369{
370 struct spi_master *master;
371
David Brownell0c868462006-01-08 13:34:25 -0800372 if (!dev)
373 return NULL;
374
Christoph Lametere94b1762006-12-06 20:33:17 -0800375 master = kzalloc(size + sizeof *master, GFP_KERNEL);
David Brownell8ae12a02006-01-08 13:34:19 -0800376 if (!master)
377 return NULL;
378
Tony Jones49dce682007-10-16 01:27:48 -0700379 device_initialize(&master->dev);
380 master->dev.class = &spi_master_class;
381 master->dev.parent = get_device(dev);
David Brownell0c868462006-01-08 13:34:25 -0800382 spi_master_set_devdata(master, &master[1]);
David Brownell8ae12a02006-01-08 13:34:19 -0800383
384 return master;
385}
386EXPORT_SYMBOL_GPL(spi_alloc_master);
387
388/**
389 * spi_register_master - register SPI master controller
390 * @master: initialized master, originally from spi_alloc_master()
David Brownell33e34dc2007-05-08 00:32:21 -0700391 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800392 *
393 * SPI master controllers connect to their drivers using some non-SPI bus,
394 * such as the platform bus. The final stage of probe() in that code
395 * includes calling spi_register_master() to hook up to this SPI bus glue.
396 *
397 * SPI controllers use board specific (often SOC specific) bus numbers,
398 * and board-specific addressing for SPI devices combines those numbers
399 * with chip select numbers. Since SPI does not directly support dynamic
400 * device identification, boards need configuration tables telling which
401 * chip is at which address.
402 *
403 * This must be called from context that can sleep. It returns zero on
404 * success, else a negative error code (dropping the master's refcount).
David Brownell0c868462006-01-08 13:34:25 -0800405 * After a successful return, the caller is responsible for calling
406 * spi_unregister_master().
David Brownell8ae12a02006-01-08 13:34:19 -0800407 */
Adrian Bunke9d5a462007-03-26 21:32:23 -0800408int spi_register_master(struct spi_master *master)
David Brownell8ae12a02006-01-08 13:34:19 -0800409{
David Brownelle44a45a2007-06-03 13:50:40 -0700410 static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
Tony Jones49dce682007-10-16 01:27:48 -0700411 struct device *dev = master->dev.parent;
David Brownell8ae12a02006-01-08 13:34:19 -0800412 int status = -ENODEV;
413 int dynamic = 0;
414
David Brownell0c868462006-01-08 13:34:25 -0800415 if (!dev)
416 return -ENODEV;
417
David Brownell082c8cb2007-07-31 00:39:45 -0700418 /* even if it's just one always-selected device, there must
419 * be at least one chipselect
420 */
421 if (master->num_chipselect == 0)
422 return -EINVAL;
423
David Brownell8ae12a02006-01-08 13:34:19 -0800424 /* convention: dynamically assigned bus IDs count down from the max */
David Brownella020ed72006-04-03 15:49:04 -0700425 if (master->bus_num < 0) {
David Brownell082c8cb2007-07-31 00:39:45 -0700426 /* FIXME switch to an IDR based scheme, something like
427 * I2C now uses, so we can't run out of "dynamic" IDs
428 */
David Brownell8ae12a02006-01-08 13:34:19 -0800429 master->bus_num = atomic_dec_return(&dyn_bus_id);
David Brownellb8852442006-01-08 13:34:23 -0800430 dynamic = 1;
David Brownell8ae12a02006-01-08 13:34:19 -0800431 }
432
433 /* register the device, then userspace will see it.
434 * registration fails if the bus ID is in use.
435 */
Tony Jones49dce682007-10-16 01:27:48 -0700436 snprintf(master->dev.bus_id, sizeof master->dev.bus_id,
David Brownell8ae12a02006-01-08 13:34:19 -0800437 "spi%u", master->bus_num);
Tony Jones49dce682007-10-16 01:27:48 -0700438 status = device_add(&master->dev);
David Brownellb8852442006-01-08 13:34:23 -0800439 if (status < 0)
David Brownell8ae12a02006-01-08 13:34:19 -0800440 goto done;
Tony Jones49dce682007-10-16 01:27:48 -0700441 dev_dbg(dev, "registered master %s%s\n", master->dev.bus_id,
David Brownell8ae12a02006-01-08 13:34:19 -0800442 dynamic ? " (dynamic)" : "");
443
444 /* populate children from any spi device tables */
445 scan_boardinfo(master);
446 status = 0;
447done:
448 return status;
449}
450EXPORT_SYMBOL_GPL(spi_register_master);
451
452
Atsushi Nemoto350d0072007-11-14 16:59:22 -0800453static int __unregister(struct device *dev, void *master_dev)
David Brownell8ae12a02006-01-08 13:34:19 -0800454{
455 /* note: before about 2.6.14-rc1 this would corrupt memory: */
Atsushi Nemoto350d0072007-11-14 16:59:22 -0800456 if (dev != master_dev)
457 spi_unregister_device(to_spi_device(dev));
David Brownell8ae12a02006-01-08 13:34:19 -0800458 return 0;
459}
460
461/**
462 * spi_unregister_master - unregister SPI master controller
463 * @master: the master being unregistered
David Brownell33e34dc2007-05-08 00:32:21 -0700464 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800465 *
466 * This call is used only by SPI master controller drivers, which are the
467 * only ones directly touching chip registers.
468 *
469 * This must be called from context that can sleep.
470 */
471void spi_unregister_master(struct spi_master *master)
472{
Jeff Garzik89fc9a12006-12-06 20:35:35 -0800473 int dummy;
474
Atsushi Nemoto350d0072007-11-14 16:59:22 -0800475 dummy = device_for_each_child(master->dev.parent, &master->dev,
476 __unregister);
Tony Jones49dce682007-10-16 01:27:48 -0700477 device_unregister(&master->dev);
David Brownell8ae12a02006-01-08 13:34:19 -0800478}
479EXPORT_SYMBOL_GPL(spi_unregister_master);
480
Dave Young5ed2c832008-01-22 15:14:18 +0800481static int __spi_master_match(struct device *dev, void *data)
482{
483 struct spi_master *m;
484 u16 *bus_num = data;
485
486 m = container_of(dev, struct spi_master, dev);
487 return m->bus_num == *bus_num;
488}
489
David Brownell8ae12a02006-01-08 13:34:19 -0800490/**
491 * spi_busnum_to_master - look up master associated with bus_num
492 * @bus_num: the master's bus number
David Brownell33e34dc2007-05-08 00:32:21 -0700493 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800494 *
495 * This call may be used with devices that are registered after
496 * arch init time. It returns a refcounted pointer to the relevant
497 * spi_master (which the caller must release), or NULL if there is
498 * no such master registered.
499 */
500struct spi_master *spi_busnum_to_master(u16 bus_num)
501{
Tony Jones49dce682007-10-16 01:27:48 -0700502 struct device *dev;
Atsushi Nemoto1e9a51d2007-01-26 00:56:54 -0800503 struct spi_master *master = NULL;
David Brownell8ae12a02006-01-08 13:34:19 -0800504
Dave Young5ed2c832008-01-22 15:14:18 +0800505 dev = class_find_device(&spi_master_class, &bus_num,
506 __spi_master_match);
507 if (dev)
508 master = container_of(dev, struct spi_master, dev);
509 /* reference got in class_find_device */
Atsushi Nemoto1e9a51d2007-01-26 00:56:54 -0800510 return master;
David Brownell8ae12a02006-01-08 13:34:19 -0800511}
512EXPORT_SYMBOL_GPL(spi_busnum_to_master);
513
514
515/*-------------------------------------------------------------------------*/
516
Andrew Morton5d870c82006-01-11 11:23:49 -0800517static void spi_complete(void *arg)
518{
519 complete(arg);
520}
521
David Brownell8ae12a02006-01-08 13:34:19 -0800522/**
523 * spi_sync - blocking/synchronous SPI data transfers
524 * @spi: device with which data will be exchanged
525 * @message: describes the data transfers
David Brownell33e34dc2007-05-08 00:32:21 -0700526 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800527 *
528 * This call may only be used from a context that may sleep. The sleep
529 * is non-interruptible, and has no timeout. Low-overhead controller
530 * drivers may DMA directly into and out of the message buffers.
531 *
532 * Note that the SPI device's chip select is active during the message,
533 * and then is normally disabled between messages. Drivers for some
534 * frequently-used devices may want to minimize costs of selecting a chip,
535 * by leaving it selected in anticipation that the next message will go
536 * to the same chip. (That may increase power usage.)
537 *
David Brownell0c868462006-01-08 13:34:25 -0800538 * Also, the caller is guaranteeing that the memory associated with the
539 * message will not be freed before this call returns.
540 *
Marc Pignat9b938b72007-12-04 23:45:10 -0800541 * It returns zero on success, else a negative error code.
David Brownell8ae12a02006-01-08 13:34:19 -0800542 */
543int spi_sync(struct spi_device *spi, struct spi_message *message)
544{
Ingo Molnar60be6b92006-07-03 00:25:26 -0700545 DECLARE_COMPLETION_ONSTACK(done);
David Brownell8ae12a02006-01-08 13:34:19 -0800546 int status;
547
Andrew Morton5d870c82006-01-11 11:23:49 -0800548 message->complete = spi_complete;
David Brownell8ae12a02006-01-08 13:34:19 -0800549 message->context = &done;
550 status = spi_async(spi, message);
Marc Pignat9b938b72007-12-04 23:45:10 -0800551 if (status == 0) {
David Brownell8ae12a02006-01-08 13:34:19 -0800552 wait_for_completion(&done);
Marc Pignat9b938b72007-12-04 23:45:10 -0800553 status = message->status;
554 }
David Brownell8ae12a02006-01-08 13:34:19 -0800555 message->context = NULL;
556 return status;
557}
558EXPORT_SYMBOL_GPL(spi_sync);
559
David Brownella9948b62006-04-02 10:37:40 -0800560/* portable code must never pass more than 32 bytes */
561#define SPI_BUFSIZ max(32,SMP_CACHE_BYTES)
David Brownell8ae12a02006-01-08 13:34:19 -0800562
563static u8 *buf;
564
565/**
566 * spi_write_then_read - SPI synchronous write followed by read
567 * @spi: device with which data will be exchanged
568 * @txbuf: data to be written (need not be dma-safe)
569 * @n_tx: size of txbuf, in bytes
570 * @rxbuf: buffer into which data will be read
571 * @n_rx: size of rxbuf, in bytes (need not be dma-safe)
David Brownell33e34dc2007-05-08 00:32:21 -0700572 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800573 *
574 * This performs a half duplex MicroWire style transaction with the
575 * device, sending txbuf and then reading rxbuf. The return value
576 * is zero for success, else a negative errno status code.
David Brownellb8852442006-01-08 13:34:23 -0800577 * This call may only be used from a context that may sleep.
David Brownell8ae12a02006-01-08 13:34:19 -0800578 *
David Brownell0c868462006-01-08 13:34:25 -0800579 * Parameters to this routine are always copied using a small buffer;
David Brownell33e34dc2007-05-08 00:32:21 -0700580 * portable code should never use this for more than 32 bytes.
581 * Performance-sensitive or bulk transfer code should instead use
David Brownell0c868462006-01-08 13:34:25 -0800582 * spi_{async,sync}() calls with dma-safe buffers.
David Brownell8ae12a02006-01-08 13:34:19 -0800583 */
584int spi_write_then_read(struct spi_device *spi,
585 const u8 *txbuf, unsigned n_tx,
586 u8 *rxbuf, unsigned n_rx)
587{
David Brownell068f4072007-12-04 23:45:09 -0800588 static DEFINE_MUTEX(lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800589
590 int status;
591 struct spi_message message;
592 struct spi_transfer x[2];
593 u8 *local_buf;
594
595 /* Use preallocated DMA-safe buffer. We can't avoid copying here,
596 * (as a pure convenience thing), but we can keep heap costs
597 * out of the hot path ...
598 */
599 if ((n_tx + n_rx) > SPI_BUFSIZ)
600 return -EINVAL;
601
Vitaly Wool8275c642006-01-08 13:34:28 -0800602 spi_message_init(&message);
603 memset(x, 0, sizeof x);
604 if (n_tx) {
605 x[0].len = n_tx;
606 spi_message_add_tail(&x[0], &message);
607 }
608 if (n_rx) {
609 x[1].len = n_rx;
610 spi_message_add_tail(&x[1], &message);
611 }
612
David Brownell8ae12a02006-01-08 13:34:19 -0800613 /* ... unless someone else is using the pre-allocated buffer */
David Brownell068f4072007-12-04 23:45:09 -0800614 if (!mutex_trylock(&lock)) {
David Brownell8ae12a02006-01-08 13:34:19 -0800615 local_buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
616 if (!local_buf)
617 return -ENOMEM;
618 } else
619 local_buf = buf;
620
David Brownell8ae12a02006-01-08 13:34:19 -0800621 memcpy(local_buf, txbuf, n_tx);
622 x[0].tx_buf = local_buf;
David Brownell8ae12a02006-01-08 13:34:19 -0800623 x[1].rx_buf = local_buf + n_tx;
David Brownell8ae12a02006-01-08 13:34:19 -0800624
625 /* do the i/o */
David Brownell8ae12a02006-01-08 13:34:19 -0800626 status = spi_sync(spi, &message);
Marc Pignat9b938b72007-12-04 23:45:10 -0800627 if (status == 0)
David Brownell8ae12a02006-01-08 13:34:19 -0800628 memcpy(rxbuf, x[1].rx_buf, n_rx);
David Brownell8ae12a02006-01-08 13:34:19 -0800629
630 if (x[0].tx_buf == buf)
David Brownell068f4072007-12-04 23:45:09 -0800631 mutex_unlock(&lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800632 else
633 kfree(local_buf);
634
635 return status;
636}
637EXPORT_SYMBOL_GPL(spi_write_then_read);
638
639/*-------------------------------------------------------------------------*/
640
641static int __init spi_init(void)
642{
David Brownellb8852442006-01-08 13:34:23 -0800643 int status;
David Brownell8ae12a02006-01-08 13:34:19 -0800644
Christoph Lametere94b1762006-12-06 20:33:17 -0800645 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
David Brownellb8852442006-01-08 13:34:23 -0800646 if (!buf) {
647 status = -ENOMEM;
648 goto err0;
649 }
650
651 status = bus_register(&spi_bus_type);
652 if (status < 0)
653 goto err1;
654
655 status = class_register(&spi_master_class);
656 if (status < 0)
657 goto err2;
David Brownell8ae12a02006-01-08 13:34:19 -0800658 return 0;
David Brownellb8852442006-01-08 13:34:23 -0800659
660err2:
661 bus_unregister(&spi_bus_type);
662err1:
663 kfree(buf);
664 buf = NULL;
665err0:
666 return status;
David Brownell8ae12a02006-01-08 13:34:19 -0800667}
David Brownellb8852442006-01-08 13:34:23 -0800668
David Brownell8ae12a02006-01-08 13:34:19 -0800669/* board_info is normally registered in arch_initcall(),
670 * but even essential drivers wait till later
David Brownellb8852442006-01-08 13:34:23 -0800671 *
672 * REVISIT only boardinfo really needs static linking. the rest (device and
673 * driver registration) _could_ be dynamically linked (modular) ... costs
674 * include needing to have boardinfo data structures be much more public.
David Brownell8ae12a02006-01-08 13:34:19 -0800675 */
676subsys_initcall(spi_init);
677