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8ae12a0d DB |
1 | /* |
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 | ||
8ae12a0d DB |
21 | #include <linux/kernel.h> |
22 | #include <linux/device.h> | |
23 | #include <linux/init.h> | |
24 | #include <linux/cache.h> | |
94040828 | 25 | #include <linux/mutex.h> |
5a0e3ad6 | 26 | #include <linux/slab.h> |
e0626e38 | 27 | #include <linux/mod_devicetable.h> |
8ae12a0d DB |
28 | #include <linux/spi/spi.h> |
29 | ||
30 | ||
b885244e DB |
31 | /* SPI bustype and spi_master class are registered after board init code |
32 | * provides the SPI device tables, ensuring that both are present by the | |
33 | * time controller driver registration causes spi_devices to "enumerate". | |
8ae12a0d DB |
34 | */ |
35 | static void spidev_release(struct device *dev) | |
36 | { | |
0ffa0285 | 37 | struct spi_device *spi = to_spi_device(dev); |
8ae12a0d DB |
38 | |
39 | /* spi masters may cleanup for released devices */ | |
40 | if (spi->master->cleanup) | |
41 | spi->master->cleanup(spi); | |
42 | ||
0c868461 | 43 | spi_master_put(spi->master); |
8ae12a0d DB |
44 | kfree(dev); |
45 | } | |
46 | ||
47 | static ssize_t | |
48 | modalias_show(struct device *dev, struct device_attribute *a, char *buf) | |
49 | { | |
50 | const struct spi_device *spi = to_spi_device(dev); | |
51 | ||
35f74fca | 52 | return sprintf(buf, "%s\n", spi->modalias); |
8ae12a0d DB |
53 | } |
54 | ||
55 | static struct device_attribute spi_dev_attrs[] = { | |
56 | __ATTR_RO(modalias), | |
57 | __ATTR_NULL, | |
58 | }; | |
59 | ||
60 | /* modalias support makes "modprobe $MODALIAS" new-style hotplug work, | |
61 | * and the sysfs version makes coldplug work too. | |
62 | */ | |
63 | ||
75368bf6 AV |
64 | static const struct spi_device_id *spi_match_id(const struct spi_device_id *id, |
65 | const struct spi_device *sdev) | |
66 | { | |
67 | while (id->name[0]) { | |
68 | if (!strcmp(sdev->modalias, id->name)) | |
69 | return id; | |
70 | id++; | |
71 | } | |
72 | return NULL; | |
73 | } | |
74 | ||
75 | const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev) | |
76 | { | |
77 | const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver); | |
78 | ||
79 | return spi_match_id(sdrv->id_table, sdev); | |
80 | } | |
81 | EXPORT_SYMBOL_GPL(spi_get_device_id); | |
82 | ||
8ae12a0d DB |
83 | static int spi_match_device(struct device *dev, struct device_driver *drv) |
84 | { | |
85 | const struct spi_device *spi = to_spi_device(dev); | |
75368bf6 AV |
86 | const struct spi_driver *sdrv = to_spi_driver(drv); |
87 | ||
88 | if (sdrv->id_table) | |
89 | return !!spi_match_id(sdrv->id_table, spi); | |
8ae12a0d | 90 | |
35f74fca | 91 | return strcmp(spi->modalias, drv->name) == 0; |
8ae12a0d DB |
92 | } |
93 | ||
7eff2e7a | 94 | static int spi_uevent(struct device *dev, struct kobj_uevent_env *env) |
8ae12a0d DB |
95 | { |
96 | const struct spi_device *spi = to_spi_device(dev); | |
97 | ||
e0626e38 | 98 | add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias); |
8ae12a0d DB |
99 | return 0; |
100 | } | |
101 | ||
102 | #ifdef CONFIG_PM | |
103 | ||
8ae12a0d DB |
104 | static int spi_suspend(struct device *dev, pm_message_t message) |
105 | { | |
3c72426f | 106 | int value = 0; |
b885244e | 107 | struct spi_driver *drv = to_spi_driver(dev->driver); |
8ae12a0d | 108 | |
8ae12a0d | 109 | /* suspend will stop irqs and dma; no more i/o */ |
3c72426f DB |
110 | if (drv) { |
111 | if (drv->suspend) | |
112 | value = drv->suspend(to_spi_device(dev), message); | |
113 | else | |
114 | dev_dbg(dev, "... can't suspend\n"); | |
115 | } | |
8ae12a0d DB |
116 | return value; |
117 | } | |
118 | ||
119 | static int spi_resume(struct device *dev) | |
120 | { | |
3c72426f | 121 | int value = 0; |
b885244e | 122 | struct spi_driver *drv = to_spi_driver(dev->driver); |
8ae12a0d | 123 | |
8ae12a0d | 124 | /* resume may restart the i/o queue */ |
3c72426f DB |
125 | if (drv) { |
126 | if (drv->resume) | |
127 | value = drv->resume(to_spi_device(dev)); | |
128 | else | |
129 | dev_dbg(dev, "... can't resume\n"); | |
130 | } | |
8ae12a0d DB |
131 | return value; |
132 | } | |
133 | ||
134 | #else | |
135 | #define spi_suspend NULL | |
136 | #define spi_resume NULL | |
137 | #endif | |
138 | ||
139 | struct bus_type spi_bus_type = { | |
140 | .name = "spi", | |
141 | .dev_attrs = spi_dev_attrs, | |
142 | .match = spi_match_device, | |
143 | .uevent = spi_uevent, | |
144 | .suspend = spi_suspend, | |
145 | .resume = spi_resume, | |
146 | }; | |
147 | EXPORT_SYMBOL_GPL(spi_bus_type); | |
148 | ||
b885244e DB |
149 | |
150 | static int spi_drv_probe(struct device *dev) | |
151 | { | |
152 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); | |
153 | ||
154 | return sdrv->probe(to_spi_device(dev)); | |
155 | } | |
156 | ||
157 | static int spi_drv_remove(struct device *dev) | |
158 | { | |
159 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); | |
160 | ||
161 | return sdrv->remove(to_spi_device(dev)); | |
162 | } | |
163 | ||
164 | static void spi_drv_shutdown(struct device *dev) | |
165 | { | |
166 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); | |
167 | ||
168 | sdrv->shutdown(to_spi_device(dev)); | |
169 | } | |
170 | ||
33e34dc6 DB |
171 | /** |
172 | * spi_register_driver - register a SPI driver | |
173 | * @sdrv: the driver to register | |
174 | * Context: can sleep | |
175 | */ | |
b885244e DB |
176 | int spi_register_driver(struct spi_driver *sdrv) |
177 | { | |
178 | sdrv->driver.bus = &spi_bus_type; | |
179 | if (sdrv->probe) | |
180 | sdrv->driver.probe = spi_drv_probe; | |
181 | if (sdrv->remove) | |
182 | sdrv->driver.remove = spi_drv_remove; | |
183 | if (sdrv->shutdown) | |
184 | sdrv->driver.shutdown = spi_drv_shutdown; | |
185 | return driver_register(&sdrv->driver); | |
186 | } | |
187 | EXPORT_SYMBOL_GPL(spi_register_driver); | |
188 | ||
8ae12a0d DB |
189 | /*-------------------------------------------------------------------------*/ |
190 | ||
191 | /* SPI devices should normally not be created by SPI device drivers; that | |
192 | * would make them board-specific. Similarly with SPI master drivers. | |
193 | * Device registration normally goes into like arch/.../mach.../board-YYY.c | |
194 | * with other readonly (flashable) information about mainboard devices. | |
195 | */ | |
196 | ||
197 | struct boardinfo { | |
198 | struct list_head list; | |
199 | unsigned n_board_info; | |
200 | struct spi_board_info board_info[0]; | |
201 | }; | |
202 | ||
203 | static LIST_HEAD(board_list); | |
94040828 | 204 | static DEFINE_MUTEX(board_lock); |
8ae12a0d | 205 | |
dc87c98e GL |
206 | /** |
207 | * spi_alloc_device - Allocate a new SPI device | |
208 | * @master: Controller to which device is connected | |
209 | * Context: can sleep | |
210 | * | |
211 | * Allows a driver to allocate and initialize a spi_device without | |
212 | * registering it immediately. This allows a driver to directly | |
213 | * fill the spi_device with device parameters before calling | |
214 | * spi_add_device() on it. | |
215 | * | |
216 | * Caller is responsible to call spi_add_device() on the returned | |
217 | * spi_device structure to add it to the SPI master. If the caller | |
218 | * needs to discard the spi_device without adding it, then it should | |
219 | * call spi_dev_put() on it. | |
220 | * | |
221 | * Returns a pointer to the new device, or NULL. | |
222 | */ | |
223 | struct spi_device *spi_alloc_device(struct spi_master *master) | |
224 | { | |
225 | struct spi_device *spi; | |
226 | struct device *dev = master->dev.parent; | |
227 | ||
228 | if (!spi_master_get(master)) | |
229 | return NULL; | |
230 | ||
231 | spi = kzalloc(sizeof *spi, GFP_KERNEL); | |
232 | if (!spi) { | |
233 | dev_err(dev, "cannot alloc spi_device\n"); | |
234 | spi_master_put(master); | |
235 | return NULL; | |
236 | } | |
237 | ||
238 | spi->master = master; | |
239 | spi->dev.parent = dev; | |
240 | spi->dev.bus = &spi_bus_type; | |
241 | spi->dev.release = spidev_release; | |
242 | device_initialize(&spi->dev); | |
243 | return spi; | |
244 | } | |
245 | EXPORT_SYMBOL_GPL(spi_alloc_device); | |
246 | ||
247 | /** | |
248 | * spi_add_device - Add spi_device allocated with spi_alloc_device | |
249 | * @spi: spi_device to register | |
250 | * | |
251 | * Companion function to spi_alloc_device. Devices allocated with | |
252 | * spi_alloc_device can be added onto the spi bus with this function. | |
253 | * | |
e48880e0 | 254 | * Returns 0 on success; negative errno on failure |
dc87c98e GL |
255 | */ |
256 | int spi_add_device(struct spi_device *spi) | |
257 | { | |
e48880e0 | 258 | static DEFINE_MUTEX(spi_add_lock); |
dc87c98e | 259 | struct device *dev = spi->master->dev.parent; |
8ec130a0 | 260 | struct device *d; |
dc87c98e GL |
261 | int status; |
262 | ||
263 | /* Chipselects are numbered 0..max; validate. */ | |
264 | if (spi->chip_select >= spi->master->num_chipselect) { | |
265 | dev_err(dev, "cs%d >= max %d\n", | |
266 | spi->chip_select, | |
267 | spi->master->num_chipselect); | |
268 | return -EINVAL; | |
269 | } | |
270 | ||
271 | /* Set the bus ID string */ | |
35f74fca | 272 | dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev), |
dc87c98e GL |
273 | spi->chip_select); |
274 | ||
e48880e0 DB |
275 | |
276 | /* We need to make sure there's no other device with this | |
277 | * chipselect **BEFORE** we call setup(), else we'll trash | |
278 | * its configuration. Lock against concurrent add() calls. | |
279 | */ | |
280 | mutex_lock(&spi_add_lock); | |
281 | ||
8ec130a0 RT |
282 | d = bus_find_device_by_name(&spi_bus_type, NULL, dev_name(&spi->dev)); |
283 | if (d != NULL) { | |
e48880e0 DB |
284 | dev_err(dev, "chipselect %d already in use\n", |
285 | spi->chip_select); | |
8ec130a0 | 286 | put_device(d); |
e48880e0 DB |
287 | status = -EBUSY; |
288 | goto done; | |
289 | } | |
290 | ||
291 | /* Drivers may modify this initial i/o setup, but will | |
292 | * normally rely on the device being setup. Devices | |
293 | * using SPI_CS_HIGH can't coexist well otherwise... | |
294 | */ | |
7d077197 | 295 | status = spi_setup(spi); |
dc87c98e GL |
296 | if (status < 0) { |
297 | dev_err(dev, "can't %s %s, status %d\n", | |
35f74fca | 298 | "setup", dev_name(&spi->dev), status); |
e48880e0 | 299 | goto done; |
dc87c98e GL |
300 | } |
301 | ||
e48880e0 | 302 | /* Device may be bound to an active driver when this returns */ |
dc87c98e | 303 | status = device_add(&spi->dev); |
e48880e0 | 304 | if (status < 0) |
dc87c98e | 305 | dev_err(dev, "can't %s %s, status %d\n", |
35f74fca | 306 | "add", dev_name(&spi->dev), status); |
e48880e0 | 307 | else |
35f74fca | 308 | dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev)); |
dc87c98e | 309 | |
e48880e0 DB |
310 | done: |
311 | mutex_unlock(&spi_add_lock); | |
312 | return status; | |
dc87c98e GL |
313 | } |
314 | EXPORT_SYMBOL_GPL(spi_add_device); | |
8ae12a0d | 315 | |
33e34dc6 DB |
316 | /** |
317 | * spi_new_device - instantiate one new SPI device | |
318 | * @master: Controller to which device is connected | |
319 | * @chip: Describes the SPI device | |
320 | * Context: can sleep | |
321 | * | |
322 | * On typical mainboards, this is purely internal; and it's not needed | |
8ae12a0d DB |
323 | * after board init creates the hard-wired devices. Some development |
324 | * platforms may not be able to use spi_register_board_info though, and | |
325 | * this is exported so that for example a USB or parport based adapter | |
326 | * driver could add devices (which it would learn about out-of-band). | |
082c8cb4 DB |
327 | * |
328 | * Returns the new device, or NULL. | |
8ae12a0d | 329 | */ |
e9d5a461 AB |
330 | struct spi_device *spi_new_device(struct spi_master *master, |
331 | struct spi_board_info *chip) | |
8ae12a0d DB |
332 | { |
333 | struct spi_device *proxy; | |
8ae12a0d DB |
334 | int status; |
335 | ||
082c8cb4 DB |
336 | /* NOTE: caller did any chip->bus_num checks necessary. |
337 | * | |
338 | * Also, unless we change the return value convention to use | |
339 | * error-or-pointer (not NULL-or-pointer), troubleshootability | |
340 | * suggests syslogged diagnostics are best here (ugh). | |
341 | */ | |
342 | ||
dc87c98e GL |
343 | proxy = spi_alloc_device(master); |
344 | if (!proxy) | |
8ae12a0d DB |
345 | return NULL; |
346 | ||
102eb975 GL |
347 | WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias)); |
348 | ||
8ae12a0d DB |
349 | proxy->chip_select = chip->chip_select; |
350 | proxy->max_speed_hz = chip->max_speed_hz; | |
980a01c9 | 351 | proxy->mode = chip->mode; |
8ae12a0d | 352 | proxy->irq = chip->irq; |
102eb975 | 353 | strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias)); |
8ae12a0d DB |
354 | proxy->dev.platform_data = (void *) chip->platform_data; |
355 | proxy->controller_data = chip->controller_data; | |
356 | proxy->controller_state = NULL; | |
8ae12a0d | 357 | |
dc87c98e | 358 | status = spi_add_device(proxy); |
8ae12a0d | 359 | if (status < 0) { |
dc87c98e GL |
360 | spi_dev_put(proxy); |
361 | return NULL; | |
8ae12a0d DB |
362 | } |
363 | ||
8ae12a0d DB |
364 | return proxy; |
365 | } | |
366 | EXPORT_SYMBOL_GPL(spi_new_device); | |
367 | ||
33e34dc6 DB |
368 | /** |
369 | * spi_register_board_info - register SPI devices for a given board | |
370 | * @info: array of chip descriptors | |
371 | * @n: how many descriptors are provided | |
372 | * Context: can sleep | |
373 | * | |
8ae12a0d DB |
374 | * Board-specific early init code calls this (probably during arch_initcall) |
375 | * with segments of the SPI device table. Any device nodes are created later, | |
376 | * after the relevant parent SPI controller (bus_num) is defined. We keep | |
377 | * this table of devices forever, so that reloading a controller driver will | |
378 | * not make Linux forget about these hard-wired devices. | |
379 | * | |
380 | * Other code can also call this, e.g. a particular add-on board might provide | |
381 | * SPI devices through its expansion connector, so code initializing that board | |
382 | * would naturally declare its SPI devices. | |
383 | * | |
384 | * The board info passed can safely be __initdata ... but be careful of | |
385 | * any embedded pointers (platform_data, etc), they're copied as-is. | |
386 | */ | |
387 | int __init | |
388 | spi_register_board_info(struct spi_board_info const *info, unsigned n) | |
389 | { | |
390 | struct boardinfo *bi; | |
391 | ||
b885244e | 392 | bi = kmalloc(sizeof(*bi) + n * sizeof *info, GFP_KERNEL); |
8ae12a0d DB |
393 | if (!bi) |
394 | return -ENOMEM; | |
395 | bi->n_board_info = n; | |
b885244e | 396 | memcpy(bi->board_info, info, n * sizeof *info); |
8ae12a0d | 397 | |
94040828 | 398 | mutex_lock(&board_lock); |
8ae12a0d | 399 | list_add_tail(&bi->list, &board_list); |
94040828 | 400 | mutex_unlock(&board_lock); |
8ae12a0d DB |
401 | return 0; |
402 | } | |
8ae12a0d DB |
403 | |
404 | /* FIXME someone should add support for a __setup("spi", ...) that | |
405 | * creates board info from kernel command lines | |
406 | */ | |
407 | ||
149a6501 | 408 | static void scan_boardinfo(struct spi_master *master) |
8ae12a0d DB |
409 | { |
410 | struct boardinfo *bi; | |
8ae12a0d | 411 | |
94040828 | 412 | mutex_lock(&board_lock); |
8ae12a0d DB |
413 | list_for_each_entry(bi, &board_list, list) { |
414 | struct spi_board_info *chip = bi->board_info; | |
415 | unsigned n; | |
416 | ||
417 | for (n = bi->n_board_info; n > 0; n--, chip++) { | |
418 | if (chip->bus_num != master->bus_num) | |
419 | continue; | |
082c8cb4 DB |
420 | /* NOTE: this relies on spi_new_device to |
421 | * issue diagnostics when given bogus inputs | |
8ae12a0d | 422 | */ |
8ae12a0d DB |
423 | (void) spi_new_device(master, chip); |
424 | } | |
425 | } | |
94040828 | 426 | mutex_unlock(&board_lock); |
8ae12a0d DB |
427 | } |
428 | ||
429 | /*-------------------------------------------------------------------------*/ | |
430 | ||
49dce689 | 431 | static void spi_master_release(struct device *dev) |
8ae12a0d DB |
432 | { |
433 | struct spi_master *master; | |
434 | ||
49dce689 | 435 | master = container_of(dev, struct spi_master, dev); |
8ae12a0d DB |
436 | kfree(master); |
437 | } | |
438 | ||
439 | static struct class spi_master_class = { | |
440 | .name = "spi_master", | |
441 | .owner = THIS_MODULE, | |
49dce689 | 442 | .dev_release = spi_master_release, |
8ae12a0d DB |
443 | }; |
444 | ||
445 | ||
446 | /** | |
447 | * spi_alloc_master - allocate SPI master controller | |
448 | * @dev: the controller, possibly using the platform_bus | |
33e34dc6 | 449 | * @size: how much zeroed driver-private data to allocate; the pointer to this |
49dce689 | 450 | * memory is in the driver_data field of the returned device, |
0c868461 | 451 | * accessible with spi_master_get_devdata(). |
33e34dc6 | 452 | * Context: can sleep |
8ae12a0d DB |
453 | * |
454 | * This call is used only by SPI master controller drivers, which are the | |
455 | * only ones directly touching chip registers. It's how they allocate | |
ba1a0513 | 456 | * an spi_master structure, prior to calling spi_register_master(). |
8ae12a0d DB |
457 | * |
458 | * This must be called from context that can sleep. It returns the SPI | |
459 | * master structure on success, else NULL. | |
460 | * | |
461 | * The caller is responsible for assigning the bus number and initializing | |
ba1a0513 | 462 | * the master's methods before calling spi_register_master(); and (after errors |
0c868461 | 463 | * adding the device) calling spi_master_put() to prevent a memory leak. |
8ae12a0d | 464 | */ |
e9d5a461 | 465 | struct spi_master *spi_alloc_master(struct device *dev, unsigned size) |
8ae12a0d DB |
466 | { |
467 | struct spi_master *master; | |
468 | ||
0c868461 DB |
469 | if (!dev) |
470 | return NULL; | |
471 | ||
e94b1766 | 472 | master = kzalloc(size + sizeof *master, GFP_KERNEL); |
8ae12a0d DB |
473 | if (!master) |
474 | return NULL; | |
475 | ||
49dce689 TJ |
476 | device_initialize(&master->dev); |
477 | master->dev.class = &spi_master_class; | |
478 | master->dev.parent = get_device(dev); | |
0c868461 | 479 | spi_master_set_devdata(master, &master[1]); |
8ae12a0d DB |
480 | |
481 | return master; | |
482 | } | |
483 | EXPORT_SYMBOL_GPL(spi_alloc_master); | |
484 | ||
485 | /** | |
486 | * spi_register_master - register SPI master controller | |
487 | * @master: initialized master, originally from spi_alloc_master() | |
33e34dc6 | 488 | * Context: can sleep |
8ae12a0d DB |
489 | * |
490 | * SPI master controllers connect to their drivers using some non-SPI bus, | |
491 | * such as the platform bus. The final stage of probe() in that code | |
492 | * includes calling spi_register_master() to hook up to this SPI bus glue. | |
493 | * | |
494 | * SPI controllers use board specific (often SOC specific) bus numbers, | |
495 | * and board-specific addressing for SPI devices combines those numbers | |
496 | * with chip select numbers. Since SPI does not directly support dynamic | |
497 | * device identification, boards need configuration tables telling which | |
498 | * chip is at which address. | |
499 | * | |
500 | * This must be called from context that can sleep. It returns zero on | |
501 | * success, else a negative error code (dropping the master's refcount). | |
0c868461 DB |
502 | * After a successful return, the caller is responsible for calling |
503 | * spi_unregister_master(). | |
8ae12a0d | 504 | */ |
e9d5a461 | 505 | int spi_register_master(struct spi_master *master) |
8ae12a0d | 506 | { |
e44a45ae | 507 | static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1); |
49dce689 | 508 | struct device *dev = master->dev.parent; |
8ae12a0d DB |
509 | int status = -ENODEV; |
510 | int dynamic = 0; | |
511 | ||
0c868461 DB |
512 | if (!dev) |
513 | return -ENODEV; | |
514 | ||
082c8cb4 DB |
515 | /* even if it's just one always-selected device, there must |
516 | * be at least one chipselect | |
517 | */ | |
518 | if (master->num_chipselect == 0) | |
519 | return -EINVAL; | |
520 | ||
8ae12a0d | 521 | /* convention: dynamically assigned bus IDs count down from the max */ |
a020ed75 | 522 | if (master->bus_num < 0) { |
082c8cb4 DB |
523 | /* FIXME switch to an IDR based scheme, something like |
524 | * I2C now uses, so we can't run out of "dynamic" IDs | |
525 | */ | |
8ae12a0d | 526 | master->bus_num = atomic_dec_return(&dyn_bus_id); |
b885244e | 527 | dynamic = 1; |
8ae12a0d DB |
528 | } |
529 | ||
530 | /* register the device, then userspace will see it. | |
531 | * registration fails if the bus ID is in use. | |
532 | */ | |
35f74fca | 533 | dev_set_name(&master->dev, "spi%u", master->bus_num); |
49dce689 | 534 | status = device_add(&master->dev); |
b885244e | 535 | if (status < 0) |
8ae12a0d | 536 | goto done; |
35f74fca | 537 | dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev), |
8ae12a0d DB |
538 | dynamic ? " (dynamic)" : ""); |
539 | ||
540 | /* populate children from any spi device tables */ | |
541 | scan_boardinfo(master); | |
542 | status = 0; | |
543 | done: | |
544 | return status; | |
545 | } | |
546 | EXPORT_SYMBOL_GPL(spi_register_master); | |
547 | ||
548 | ||
350d0076 | 549 | static int __unregister(struct device *dev, void *master_dev) |
8ae12a0d DB |
550 | { |
551 | /* note: before about 2.6.14-rc1 this would corrupt memory: */ | |
350d0076 AN |
552 | if (dev != master_dev) |
553 | spi_unregister_device(to_spi_device(dev)); | |
8ae12a0d DB |
554 | return 0; |
555 | } | |
556 | ||
557 | /** | |
558 | * spi_unregister_master - unregister SPI master controller | |
559 | * @master: the master being unregistered | |
33e34dc6 | 560 | * Context: can sleep |
8ae12a0d DB |
561 | * |
562 | * This call is used only by SPI master controller drivers, which are the | |
563 | * only ones directly touching chip registers. | |
564 | * | |
565 | * This must be called from context that can sleep. | |
566 | */ | |
567 | void spi_unregister_master(struct spi_master *master) | |
568 | { | |
89fc9a1a JG |
569 | int dummy; |
570 | ||
350d0076 AN |
571 | dummy = device_for_each_child(master->dev.parent, &master->dev, |
572 | __unregister); | |
49dce689 | 573 | device_unregister(&master->dev); |
8ae12a0d DB |
574 | } |
575 | EXPORT_SYMBOL_GPL(spi_unregister_master); | |
576 | ||
5ed2c832 DY |
577 | static int __spi_master_match(struct device *dev, void *data) |
578 | { | |
579 | struct spi_master *m; | |
580 | u16 *bus_num = data; | |
581 | ||
582 | m = container_of(dev, struct spi_master, dev); | |
583 | return m->bus_num == *bus_num; | |
584 | } | |
585 | ||
8ae12a0d DB |
586 | /** |
587 | * spi_busnum_to_master - look up master associated with bus_num | |
588 | * @bus_num: the master's bus number | |
33e34dc6 | 589 | * Context: can sleep |
8ae12a0d DB |
590 | * |
591 | * This call may be used with devices that are registered after | |
592 | * arch init time. It returns a refcounted pointer to the relevant | |
593 | * spi_master (which the caller must release), or NULL if there is | |
594 | * no such master registered. | |
595 | */ | |
596 | struct spi_master *spi_busnum_to_master(u16 bus_num) | |
597 | { | |
49dce689 | 598 | struct device *dev; |
1e9a51dc | 599 | struct spi_master *master = NULL; |
5ed2c832 | 600 | |
695794ae | 601 | dev = class_find_device(&spi_master_class, NULL, &bus_num, |
5ed2c832 DY |
602 | __spi_master_match); |
603 | if (dev) | |
604 | master = container_of(dev, struct spi_master, dev); | |
605 | /* reference got in class_find_device */ | |
1e9a51dc | 606 | return master; |
8ae12a0d DB |
607 | } |
608 | EXPORT_SYMBOL_GPL(spi_busnum_to_master); | |
609 | ||
610 | ||
611 | /*-------------------------------------------------------------------------*/ | |
612 | ||
7d077197 DB |
613 | /* Core methods for SPI master protocol drivers. Some of the |
614 | * other core methods are currently defined as inline functions. | |
615 | */ | |
616 | ||
617 | /** | |
618 | * spi_setup - setup SPI mode and clock rate | |
619 | * @spi: the device whose settings are being modified | |
620 | * Context: can sleep, and no requests are queued to the device | |
621 | * | |
622 | * SPI protocol drivers may need to update the transfer mode if the | |
623 | * device doesn't work with its default. They may likewise need | |
624 | * to update clock rates or word sizes from initial values. This function | |
625 | * changes those settings, and must be called from a context that can sleep. | |
626 | * Except for SPI_CS_HIGH, which takes effect immediately, the changes take | |
627 | * effect the next time the device is selected and data is transferred to | |
628 | * or from it. When this function returns, the spi device is deselected. | |
629 | * | |
630 | * Note that this call will fail if the protocol driver specifies an option | |
631 | * that the underlying controller or its driver does not support. For | |
632 | * example, not all hardware supports wire transfers using nine bit words, | |
633 | * LSB-first wire encoding, or active-high chipselects. | |
634 | */ | |
635 | int spi_setup(struct spi_device *spi) | |
636 | { | |
e7db06b5 | 637 | unsigned bad_bits; |
7d077197 DB |
638 | int status; |
639 | ||
e7db06b5 DB |
640 | /* help drivers fail *cleanly* when they need options |
641 | * that aren't supported with their current master | |
642 | */ | |
643 | bad_bits = spi->mode & ~spi->master->mode_bits; | |
644 | if (bad_bits) { | |
645 | dev_dbg(&spi->dev, "setup: unsupported mode bits %x\n", | |
646 | bad_bits); | |
647 | return -EINVAL; | |
648 | } | |
649 | ||
7d077197 DB |
650 | if (!spi->bits_per_word) |
651 | spi->bits_per_word = 8; | |
652 | ||
653 | status = spi->master->setup(spi); | |
654 | ||
655 | dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s" | |
656 | "%u bits/w, %u Hz max --> %d\n", | |
657 | (int) (spi->mode & (SPI_CPOL | SPI_CPHA)), | |
658 | (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "", | |
659 | (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "", | |
660 | (spi->mode & SPI_3WIRE) ? "3wire, " : "", | |
661 | (spi->mode & SPI_LOOP) ? "loopback, " : "", | |
662 | spi->bits_per_word, spi->max_speed_hz, | |
663 | status); | |
664 | ||
665 | return status; | |
666 | } | |
667 | EXPORT_SYMBOL_GPL(spi_setup); | |
668 | ||
568d0697 DB |
669 | /** |
670 | * spi_async - asynchronous SPI transfer | |
671 | * @spi: device with which data will be exchanged | |
672 | * @message: describes the data transfers, including completion callback | |
673 | * Context: any (irqs may be blocked, etc) | |
674 | * | |
675 | * This call may be used in_irq and other contexts which can't sleep, | |
676 | * as well as from task contexts which can sleep. | |
677 | * | |
678 | * The completion callback is invoked in a context which can't sleep. | |
679 | * Before that invocation, the value of message->status is undefined. | |
680 | * When the callback is issued, message->status holds either zero (to | |
681 | * indicate complete success) or a negative error code. After that | |
682 | * callback returns, the driver which issued the transfer request may | |
683 | * deallocate the associated memory; it's no longer in use by any SPI | |
684 | * core or controller driver code. | |
685 | * | |
686 | * Note that although all messages to a spi_device are handled in | |
687 | * FIFO order, messages may go to different devices in other orders. | |
688 | * Some device might be higher priority, or have various "hard" access | |
689 | * time requirements, for example. | |
690 | * | |
691 | * On detection of any fault during the transfer, processing of | |
692 | * the entire message is aborted, and the device is deselected. | |
693 | * Until returning from the associated message completion callback, | |
694 | * no other spi_message queued to that device will be processed. | |
695 | * (This rule applies equally to all the synchronous transfer calls, | |
696 | * which are wrappers around this core asynchronous primitive.) | |
697 | */ | |
698 | int spi_async(struct spi_device *spi, struct spi_message *message) | |
699 | { | |
700 | struct spi_master *master = spi->master; | |
701 | ||
702 | /* Half-duplex links include original MicroWire, and ones with | |
703 | * only one data pin like SPI_3WIRE (switches direction) or where | |
704 | * either MOSI or MISO is missing. They can also be caused by | |
705 | * software limitations. | |
706 | */ | |
707 | if ((master->flags & SPI_MASTER_HALF_DUPLEX) | |
708 | || (spi->mode & SPI_3WIRE)) { | |
709 | struct spi_transfer *xfer; | |
710 | unsigned flags = master->flags; | |
711 | ||
712 | list_for_each_entry(xfer, &message->transfers, transfer_list) { | |
713 | if (xfer->rx_buf && xfer->tx_buf) | |
714 | return -EINVAL; | |
715 | if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf) | |
716 | return -EINVAL; | |
717 | if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf) | |
718 | return -EINVAL; | |
719 | } | |
720 | } | |
721 | ||
722 | message->spi = spi; | |
723 | message->status = -EINPROGRESS; | |
724 | return master->transfer(spi, message); | |
725 | } | |
726 | EXPORT_SYMBOL_GPL(spi_async); | |
727 | ||
7d077197 DB |
728 | |
729 | /*-------------------------------------------------------------------------*/ | |
730 | ||
731 | /* Utility methods for SPI master protocol drivers, layered on | |
732 | * top of the core. Some other utility methods are defined as | |
733 | * inline functions. | |
734 | */ | |
735 | ||
5d870c8e AM |
736 | static void spi_complete(void *arg) |
737 | { | |
738 | complete(arg); | |
739 | } | |
740 | ||
8ae12a0d DB |
741 | /** |
742 | * spi_sync - blocking/synchronous SPI data transfers | |
743 | * @spi: device with which data will be exchanged | |
744 | * @message: describes the data transfers | |
33e34dc6 | 745 | * Context: can sleep |
8ae12a0d DB |
746 | * |
747 | * This call may only be used from a context that may sleep. The sleep | |
748 | * is non-interruptible, and has no timeout. Low-overhead controller | |
749 | * drivers may DMA directly into and out of the message buffers. | |
750 | * | |
751 | * Note that the SPI device's chip select is active during the message, | |
752 | * and then is normally disabled between messages. Drivers for some | |
753 | * frequently-used devices may want to minimize costs of selecting a chip, | |
754 | * by leaving it selected in anticipation that the next message will go | |
755 | * to the same chip. (That may increase power usage.) | |
756 | * | |
0c868461 DB |
757 | * Also, the caller is guaranteeing that the memory associated with the |
758 | * message will not be freed before this call returns. | |
759 | * | |
9b938b74 | 760 | * It returns zero on success, else a negative error code. |
8ae12a0d DB |
761 | */ |
762 | int spi_sync(struct spi_device *spi, struct spi_message *message) | |
763 | { | |
60be6b9a | 764 | DECLARE_COMPLETION_ONSTACK(done); |
8ae12a0d DB |
765 | int status; |
766 | ||
5d870c8e | 767 | message->complete = spi_complete; |
8ae12a0d DB |
768 | message->context = &done; |
769 | status = spi_async(spi, message); | |
9b938b74 | 770 | if (status == 0) { |
8ae12a0d | 771 | wait_for_completion(&done); |
9b938b74 MP |
772 | status = message->status; |
773 | } | |
8ae12a0d DB |
774 | message->context = NULL; |
775 | return status; | |
776 | } | |
777 | EXPORT_SYMBOL_GPL(spi_sync); | |
778 | ||
a9948b61 DB |
779 | /* portable code must never pass more than 32 bytes */ |
780 | #define SPI_BUFSIZ max(32,SMP_CACHE_BYTES) | |
8ae12a0d DB |
781 | |
782 | static u8 *buf; | |
783 | ||
784 | /** | |
785 | * spi_write_then_read - SPI synchronous write followed by read | |
786 | * @spi: device with which data will be exchanged | |
787 | * @txbuf: data to be written (need not be dma-safe) | |
788 | * @n_tx: size of txbuf, in bytes | |
27570497 JP |
789 | * @rxbuf: buffer into which data will be read (need not be dma-safe) |
790 | * @n_rx: size of rxbuf, in bytes | |
33e34dc6 | 791 | * Context: can sleep |
8ae12a0d DB |
792 | * |
793 | * This performs a half duplex MicroWire style transaction with the | |
794 | * device, sending txbuf and then reading rxbuf. The return value | |
795 | * is zero for success, else a negative errno status code. | |
b885244e | 796 | * This call may only be used from a context that may sleep. |
8ae12a0d | 797 | * |
0c868461 | 798 | * Parameters to this routine are always copied using a small buffer; |
33e34dc6 DB |
799 | * portable code should never use this for more than 32 bytes. |
800 | * Performance-sensitive or bulk transfer code should instead use | |
0c868461 | 801 | * spi_{async,sync}() calls with dma-safe buffers. |
8ae12a0d DB |
802 | */ |
803 | int spi_write_then_read(struct spi_device *spi, | |
804 | const u8 *txbuf, unsigned n_tx, | |
805 | u8 *rxbuf, unsigned n_rx) | |
806 | { | |
068f4070 | 807 | static DEFINE_MUTEX(lock); |
8ae12a0d DB |
808 | |
809 | int status; | |
810 | struct spi_message message; | |
bdff549e | 811 | struct spi_transfer x[2]; |
8ae12a0d DB |
812 | u8 *local_buf; |
813 | ||
814 | /* Use preallocated DMA-safe buffer. We can't avoid copying here, | |
815 | * (as a pure convenience thing), but we can keep heap costs | |
816 | * out of the hot path ... | |
817 | */ | |
818 | if ((n_tx + n_rx) > SPI_BUFSIZ) | |
819 | return -EINVAL; | |
820 | ||
8275c642 | 821 | spi_message_init(&message); |
bdff549e DB |
822 | memset(x, 0, sizeof x); |
823 | if (n_tx) { | |
824 | x[0].len = n_tx; | |
825 | spi_message_add_tail(&x[0], &message); | |
826 | } | |
827 | if (n_rx) { | |
828 | x[1].len = n_rx; | |
829 | spi_message_add_tail(&x[1], &message); | |
830 | } | |
8275c642 | 831 | |
8ae12a0d | 832 | /* ... unless someone else is using the pre-allocated buffer */ |
068f4070 | 833 | if (!mutex_trylock(&lock)) { |
8ae12a0d DB |
834 | local_buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL); |
835 | if (!local_buf) | |
836 | return -ENOMEM; | |
837 | } else | |
838 | local_buf = buf; | |
839 | ||
8ae12a0d | 840 | memcpy(local_buf, txbuf, n_tx); |
bdff549e DB |
841 | x[0].tx_buf = local_buf; |
842 | x[1].rx_buf = local_buf + n_tx; | |
8ae12a0d DB |
843 | |
844 | /* do the i/o */ | |
8ae12a0d | 845 | status = spi_sync(spi, &message); |
9b938b74 | 846 | if (status == 0) |
bdff549e | 847 | memcpy(rxbuf, x[1].rx_buf, n_rx); |
8ae12a0d | 848 | |
bdff549e | 849 | if (x[0].tx_buf == buf) |
068f4070 | 850 | mutex_unlock(&lock); |
8ae12a0d DB |
851 | else |
852 | kfree(local_buf); | |
853 | ||
854 | return status; | |
855 | } | |
856 | EXPORT_SYMBOL_GPL(spi_write_then_read); | |
857 | ||
858 | /*-------------------------------------------------------------------------*/ | |
859 | ||
860 | static int __init spi_init(void) | |
861 | { | |
b885244e DB |
862 | int status; |
863 | ||
e94b1766 | 864 | buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL); |
b885244e DB |
865 | if (!buf) { |
866 | status = -ENOMEM; | |
867 | goto err0; | |
868 | } | |
869 | ||
870 | status = bus_register(&spi_bus_type); | |
871 | if (status < 0) | |
872 | goto err1; | |
8ae12a0d | 873 | |
b885244e DB |
874 | status = class_register(&spi_master_class); |
875 | if (status < 0) | |
876 | goto err2; | |
8ae12a0d | 877 | return 0; |
b885244e DB |
878 | |
879 | err2: | |
880 | bus_unregister(&spi_bus_type); | |
881 | err1: | |
882 | kfree(buf); | |
883 | buf = NULL; | |
884 | err0: | |
885 | return status; | |
8ae12a0d | 886 | } |
b885244e | 887 | |
8ae12a0d DB |
888 | /* board_info is normally registered in arch_initcall(), |
889 | * but even essential drivers wait till later | |
b885244e DB |
890 | * |
891 | * REVISIT only boardinfo really needs static linking. the rest (device and | |
892 | * driver registration) _could_ be dynamically linked (modular) ... costs | |
893 | * include needing to have boardinfo data structures be much more public. | |
8ae12a0d | 894 | */ |
673c0c00 | 895 | postcore_initcall(spi_init); |
8ae12a0d | 896 |