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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 | 28 | #include <linux/spi/spi.h> |
12b15e83 | 29 | #include <linux/of_spi.h> |
8ae12a0d DB |
30 | |
31 | ||
b885244e DB |
32 | /* SPI bustype and spi_master class are registered after board init code |
33 | * provides the SPI device tables, ensuring that both are present by the | |
34 | * time controller driver registration causes spi_devices to "enumerate". | |
8ae12a0d DB |
35 | */ |
36 | static void spidev_release(struct device *dev) | |
37 | { | |
0ffa0285 | 38 | struct spi_device *spi = to_spi_device(dev); |
8ae12a0d DB |
39 | |
40 | /* spi masters may cleanup for released devices */ | |
41 | if (spi->master->cleanup) | |
42 | spi->master->cleanup(spi); | |
43 | ||
0c868461 | 44 | spi_master_put(spi->master); |
07a389fe | 45 | kfree(spi); |
8ae12a0d DB |
46 | } |
47 | ||
48 | static ssize_t | |
49 | modalias_show(struct device *dev, struct device_attribute *a, char *buf) | |
50 | { | |
51 | const struct spi_device *spi = to_spi_device(dev); | |
52 | ||
35f74fca | 53 | return sprintf(buf, "%s\n", spi->modalias); |
8ae12a0d DB |
54 | } |
55 | ||
56 | static struct device_attribute spi_dev_attrs[] = { | |
57 | __ATTR_RO(modalias), | |
58 | __ATTR_NULL, | |
59 | }; | |
60 | ||
61 | /* modalias support makes "modprobe $MODALIAS" new-style hotplug work, | |
62 | * and the sysfs version makes coldplug work too. | |
63 | */ | |
64 | ||
75368bf6 AV |
65 | static const struct spi_device_id *spi_match_id(const struct spi_device_id *id, |
66 | const struct spi_device *sdev) | |
67 | { | |
68 | while (id->name[0]) { | |
69 | if (!strcmp(sdev->modalias, id->name)) | |
70 | return id; | |
71 | id++; | |
72 | } | |
73 | return NULL; | |
74 | } | |
75 | ||
76 | const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev) | |
77 | { | |
78 | const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver); | |
79 | ||
80 | return spi_match_id(sdrv->id_table, sdev); | |
81 | } | |
82 | EXPORT_SYMBOL_GPL(spi_get_device_id); | |
83 | ||
8ae12a0d DB |
84 | static int spi_match_device(struct device *dev, struct device_driver *drv) |
85 | { | |
86 | const struct spi_device *spi = to_spi_device(dev); | |
75368bf6 AV |
87 | const struct spi_driver *sdrv = to_spi_driver(drv); |
88 | ||
89 | if (sdrv->id_table) | |
90 | return !!spi_match_id(sdrv->id_table, spi); | |
8ae12a0d | 91 | |
35f74fca | 92 | return strcmp(spi->modalias, drv->name) == 0; |
8ae12a0d DB |
93 | } |
94 | ||
7eff2e7a | 95 | static int spi_uevent(struct device *dev, struct kobj_uevent_env *env) |
8ae12a0d DB |
96 | { |
97 | const struct spi_device *spi = to_spi_device(dev); | |
98 | ||
e0626e38 | 99 | add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias); |
8ae12a0d DB |
100 | return 0; |
101 | } | |
102 | ||
103 | #ifdef CONFIG_PM | |
104 | ||
8ae12a0d DB |
105 | static int spi_suspend(struct device *dev, pm_message_t message) |
106 | { | |
3c72426f | 107 | int value = 0; |
b885244e | 108 | struct spi_driver *drv = to_spi_driver(dev->driver); |
8ae12a0d | 109 | |
8ae12a0d | 110 | /* suspend will stop irqs and dma; no more i/o */ |
3c72426f DB |
111 | if (drv) { |
112 | if (drv->suspend) | |
113 | value = drv->suspend(to_spi_device(dev), message); | |
114 | else | |
115 | dev_dbg(dev, "... can't suspend\n"); | |
116 | } | |
8ae12a0d DB |
117 | return value; |
118 | } | |
119 | ||
120 | static int spi_resume(struct device *dev) | |
121 | { | |
3c72426f | 122 | int value = 0; |
b885244e | 123 | struct spi_driver *drv = to_spi_driver(dev->driver); |
8ae12a0d | 124 | |
8ae12a0d | 125 | /* resume may restart the i/o queue */ |
3c72426f DB |
126 | if (drv) { |
127 | if (drv->resume) | |
128 | value = drv->resume(to_spi_device(dev)); | |
129 | else | |
130 | dev_dbg(dev, "... can't resume\n"); | |
131 | } | |
8ae12a0d DB |
132 | return value; |
133 | } | |
134 | ||
135 | #else | |
136 | #define spi_suspend NULL | |
137 | #define spi_resume NULL | |
138 | #endif | |
139 | ||
140 | struct bus_type spi_bus_type = { | |
141 | .name = "spi", | |
142 | .dev_attrs = spi_dev_attrs, | |
143 | .match = spi_match_device, | |
144 | .uevent = spi_uevent, | |
145 | .suspend = spi_suspend, | |
146 | .resume = spi_resume, | |
147 | }; | |
148 | EXPORT_SYMBOL_GPL(spi_bus_type); | |
149 | ||
b885244e DB |
150 | |
151 | static int spi_drv_probe(struct device *dev) | |
152 | { | |
153 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); | |
154 | ||
155 | return sdrv->probe(to_spi_device(dev)); | |
156 | } | |
157 | ||
158 | static int spi_drv_remove(struct device *dev) | |
159 | { | |
160 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); | |
161 | ||
162 | return sdrv->remove(to_spi_device(dev)); | |
163 | } | |
164 | ||
165 | static void spi_drv_shutdown(struct device *dev) | |
166 | { | |
167 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); | |
168 | ||
169 | sdrv->shutdown(to_spi_device(dev)); | |
170 | } | |
171 | ||
33e34dc6 DB |
172 | /** |
173 | * spi_register_driver - register a SPI driver | |
174 | * @sdrv: the driver to register | |
175 | * Context: can sleep | |
176 | */ | |
b885244e DB |
177 | int spi_register_driver(struct spi_driver *sdrv) |
178 | { | |
179 | sdrv->driver.bus = &spi_bus_type; | |
180 | if (sdrv->probe) | |
181 | sdrv->driver.probe = spi_drv_probe; | |
182 | if (sdrv->remove) | |
183 | sdrv->driver.remove = spi_drv_remove; | |
184 | if (sdrv->shutdown) | |
185 | sdrv->driver.shutdown = spi_drv_shutdown; | |
186 | return driver_register(&sdrv->driver); | |
187 | } | |
188 | EXPORT_SYMBOL_GPL(spi_register_driver); | |
189 | ||
8ae12a0d DB |
190 | /*-------------------------------------------------------------------------*/ |
191 | ||
192 | /* SPI devices should normally not be created by SPI device drivers; that | |
193 | * would make them board-specific. Similarly with SPI master drivers. | |
194 | * Device registration normally goes into like arch/.../mach.../board-YYY.c | |
195 | * with other readonly (flashable) information about mainboard devices. | |
196 | */ | |
197 | ||
198 | struct boardinfo { | |
199 | struct list_head list; | |
200 | unsigned n_board_info; | |
201 | struct spi_board_info board_info[0]; | |
202 | }; | |
203 | ||
204 | static LIST_HEAD(board_list); | |
94040828 | 205 | static DEFINE_MUTEX(board_lock); |
8ae12a0d | 206 | |
dc87c98e GL |
207 | /** |
208 | * spi_alloc_device - Allocate a new SPI device | |
209 | * @master: Controller to which device is connected | |
210 | * Context: can sleep | |
211 | * | |
212 | * Allows a driver to allocate and initialize a spi_device without | |
213 | * registering it immediately. This allows a driver to directly | |
214 | * fill the spi_device with device parameters before calling | |
215 | * spi_add_device() on it. | |
216 | * | |
217 | * Caller is responsible to call spi_add_device() on the returned | |
218 | * spi_device structure to add it to the SPI master. If the caller | |
219 | * needs to discard the spi_device without adding it, then it should | |
220 | * call spi_dev_put() on it. | |
221 | * | |
222 | * Returns a pointer to the new device, or NULL. | |
223 | */ | |
224 | struct spi_device *spi_alloc_device(struct spi_master *master) | |
225 | { | |
226 | struct spi_device *spi; | |
227 | struct device *dev = master->dev.parent; | |
228 | ||
229 | if (!spi_master_get(master)) | |
230 | return NULL; | |
231 | ||
232 | spi = kzalloc(sizeof *spi, GFP_KERNEL); | |
233 | if (!spi) { | |
234 | dev_err(dev, "cannot alloc spi_device\n"); | |
235 | spi_master_put(master); | |
236 | return NULL; | |
237 | } | |
238 | ||
239 | spi->master = master; | |
240 | spi->dev.parent = dev; | |
241 | spi->dev.bus = &spi_bus_type; | |
242 | spi->dev.release = spidev_release; | |
243 | device_initialize(&spi->dev); | |
244 | return spi; | |
245 | } | |
246 | EXPORT_SYMBOL_GPL(spi_alloc_device); | |
247 | ||
248 | /** | |
249 | * spi_add_device - Add spi_device allocated with spi_alloc_device | |
250 | * @spi: spi_device to register | |
251 | * | |
252 | * Companion function to spi_alloc_device. Devices allocated with | |
253 | * spi_alloc_device can be added onto the spi bus with this function. | |
254 | * | |
e48880e0 | 255 | * Returns 0 on success; negative errno on failure |
dc87c98e GL |
256 | */ |
257 | int spi_add_device(struct spi_device *spi) | |
258 | { | |
e48880e0 | 259 | static DEFINE_MUTEX(spi_add_lock); |
dc87c98e | 260 | struct device *dev = spi->master->dev.parent; |
8ec130a0 | 261 | struct device *d; |
dc87c98e GL |
262 | int status; |
263 | ||
264 | /* Chipselects are numbered 0..max; validate. */ | |
265 | if (spi->chip_select >= spi->master->num_chipselect) { | |
266 | dev_err(dev, "cs%d >= max %d\n", | |
267 | spi->chip_select, | |
268 | spi->master->num_chipselect); | |
269 | return -EINVAL; | |
270 | } | |
271 | ||
272 | /* Set the bus ID string */ | |
35f74fca | 273 | dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev), |
dc87c98e GL |
274 | spi->chip_select); |
275 | ||
e48880e0 DB |
276 | |
277 | /* We need to make sure there's no other device with this | |
278 | * chipselect **BEFORE** we call setup(), else we'll trash | |
279 | * its configuration. Lock against concurrent add() calls. | |
280 | */ | |
281 | mutex_lock(&spi_add_lock); | |
282 | ||
8ec130a0 RT |
283 | d = bus_find_device_by_name(&spi_bus_type, NULL, dev_name(&spi->dev)); |
284 | if (d != NULL) { | |
e48880e0 DB |
285 | dev_err(dev, "chipselect %d already in use\n", |
286 | spi->chip_select); | |
8ec130a0 | 287 | put_device(d); |
e48880e0 DB |
288 | status = -EBUSY; |
289 | goto done; | |
290 | } | |
291 | ||
292 | /* Drivers may modify this initial i/o setup, but will | |
293 | * normally rely on the device being setup. Devices | |
294 | * using SPI_CS_HIGH can't coexist well otherwise... | |
295 | */ | |
7d077197 | 296 | status = spi_setup(spi); |
dc87c98e GL |
297 | if (status < 0) { |
298 | dev_err(dev, "can't %s %s, status %d\n", | |
35f74fca | 299 | "setup", dev_name(&spi->dev), status); |
e48880e0 | 300 | goto done; |
dc87c98e GL |
301 | } |
302 | ||
e48880e0 | 303 | /* Device may be bound to an active driver when this returns */ |
dc87c98e | 304 | status = device_add(&spi->dev); |
e48880e0 | 305 | if (status < 0) |
dc87c98e | 306 | dev_err(dev, "can't %s %s, status %d\n", |
35f74fca | 307 | "add", dev_name(&spi->dev), status); |
e48880e0 | 308 | else |
35f74fca | 309 | dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev)); |
dc87c98e | 310 | |
e48880e0 DB |
311 | done: |
312 | mutex_unlock(&spi_add_lock); | |
313 | return status; | |
dc87c98e GL |
314 | } |
315 | EXPORT_SYMBOL_GPL(spi_add_device); | |
8ae12a0d | 316 | |
33e34dc6 DB |
317 | /** |
318 | * spi_new_device - instantiate one new SPI device | |
319 | * @master: Controller to which device is connected | |
320 | * @chip: Describes the SPI device | |
321 | * Context: can sleep | |
322 | * | |
323 | * On typical mainboards, this is purely internal; and it's not needed | |
8ae12a0d DB |
324 | * after board init creates the hard-wired devices. Some development |
325 | * platforms may not be able to use spi_register_board_info though, and | |
326 | * this is exported so that for example a USB or parport based adapter | |
327 | * driver could add devices (which it would learn about out-of-band). | |
082c8cb4 DB |
328 | * |
329 | * Returns the new device, or NULL. | |
8ae12a0d | 330 | */ |
e9d5a461 AB |
331 | struct spi_device *spi_new_device(struct spi_master *master, |
332 | struct spi_board_info *chip) | |
8ae12a0d DB |
333 | { |
334 | struct spi_device *proxy; | |
8ae12a0d DB |
335 | int status; |
336 | ||
082c8cb4 DB |
337 | /* NOTE: caller did any chip->bus_num checks necessary. |
338 | * | |
339 | * Also, unless we change the return value convention to use | |
340 | * error-or-pointer (not NULL-or-pointer), troubleshootability | |
341 | * suggests syslogged diagnostics are best here (ugh). | |
342 | */ | |
343 | ||
dc87c98e GL |
344 | proxy = spi_alloc_device(master); |
345 | if (!proxy) | |
8ae12a0d DB |
346 | return NULL; |
347 | ||
102eb975 GL |
348 | WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias)); |
349 | ||
8ae12a0d DB |
350 | proxy->chip_select = chip->chip_select; |
351 | proxy->max_speed_hz = chip->max_speed_hz; | |
980a01c9 | 352 | proxy->mode = chip->mode; |
8ae12a0d | 353 | proxy->irq = chip->irq; |
102eb975 | 354 | strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias)); |
8ae12a0d DB |
355 | proxy->dev.platform_data = (void *) chip->platform_data; |
356 | proxy->controller_data = chip->controller_data; | |
357 | proxy->controller_state = NULL; | |
8ae12a0d | 358 | |
dc87c98e | 359 | status = spi_add_device(proxy); |
8ae12a0d | 360 | if (status < 0) { |
dc87c98e GL |
361 | spi_dev_put(proxy); |
362 | return NULL; | |
8ae12a0d DB |
363 | } |
364 | ||
8ae12a0d DB |
365 | return proxy; |
366 | } | |
367 | EXPORT_SYMBOL_GPL(spi_new_device); | |
368 | ||
33e34dc6 DB |
369 | /** |
370 | * spi_register_board_info - register SPI devices for a given board | |
371 | * @info: array of chip descriptors | |
372 | * @n: how many descriptors are provided | |
373 | * Context: can sleep | |
374 | * | |
8ae12a0d DB |
375 | * Board-specific early init code calls this (probably during arch_initcall) |
376 | * with segments of the SPI device table. Any device nodes are created later, | |
377 | * after the relevant parent SPI controller (bus_num) is defined. We keep | |
378 | * this table of devices forever, so that reloading a controller driver will | |
379 | * not make Linux forget about these hard-wired devices. | |
380 | * | |
381 | * Other code can also call this, e.g. a particular add-on board might provide | |
382 | * SPI devices through its expansion connector, so code initializing that board | |
383 | * would naturally declare its SPI devices. | |
384 | * | |
385 | * The board info passed can safely be __initdata ... but be careful of | |
386 | * any embedded pointers (platform_data, etc), they're copied as-is. | |
387 | */ | |
388 | int __init | |
389 | spi_register_board_info(struct spi_board_info const *info, unsigned n) | |
390 | { | |
391 | struct boardinfo *bi; | |
392 | ||
b885244e | 393 | bi = kmalloc(sizeof(*bi) + n * sizeof *info, GFP_KERNEL); |
8ae12a0d DB |
394 | if (!bi) |
395 | return -ENOMEM; | |
396 | bi->n_board_info = n; | |
b885244e | 397 | memcpy(bi->board_info, info, n * sizeof *info); |
8ae12a0d | 398 | |
94040828 | 399 | mutex_lock(&board_lock); |
8ae12a0d | 400 | list_add_tail(&bi->list, &board_list); |
94040828 | 401 | mutex_unlock(&board_lock); |
8ae12a0d DB |
402 | return 0; |
403 | } | |
8ae12a0d DB |
404 | |
405 | /* FIXME someone should add support for a __setup("spi", ...) that | |
406 | * creates board info from kernel command lines | |
407 | */ | |
408 | ||
149a6501 | 409 | static void scan_boardinfo(struct spi_master *master) |
8ae12a0d DB |
410 | { |
411 | struct boardinfo *bi; | |
8ae12a0d | 412 | |
94040828 | 413 | mutex_lock(&board_lock); |
8ae12a0d DB |
414 | list_for_each_entry(bi, &board_list, list) { |
415 | struct spi_board_info *chip = bi->board_info; | |
416 | unsigned n; | |
417 | ||
418 | for (n = bi->n_board_info; n > 0; n--, chip++) { | |
419 | if (chip->bus_num != master->bus_num) | |
420 | continue; | |
082c8cb4 DB |
421 | /* NOTE: this relies on spi_new_device to |
422 | * issue diagnostics when given bogus inputs | |
8ae12a0d | 423 | */ |
8ae12a0d DB |
424 | (void) spi_new_device(master, chip); |
425 | } | |
426 | } | |
94040828 | 427 | mutex_unlock(&board_lock); |
8ae12a0d DB |
428 | } |
429 | ||
430 | /*-------------------------------------------------------------------------*/ | |
431 | ||
49dce689 | 432 | static void spi_master_release(struct device *dev) |
8ae12a0d DB |
433 | { |
434 | struct spi_master *master; | |
435 | ||
49dce689 | 436 | master = container_of(dev, struct spi_master, dev); |
8ae12a0d DB |
437 | kfree(master); |
438 | } | |
439 | ||
440 | static struct class spi_master_class = { | |
441 | .name = "spi_master", | |
442 | .owner = THIS_MODULE, | |
49dce689 | 443 | .dev_release = spi_master_release, |
8ae12a0d DB |
444 | }; |
445 | ||
446 | ||
447 | /** | |
448 | * spi_alloc_master - allocate SPI master controller | |
449 | * @dev: the controller, possibly using the platform_bus | |
33e34dc6 | 450 | * @size: how much zeroed driver-private data to allocate; the pointer to this |
49dce689 | 451 | * memory is in the driver_data field of the returned device, |
0c868461 | 452 | * accessible with spi_master_get_devdata(). |
33e34dc6 | 453 | * Context: can sleep |
8ae12a0d DB |
454 | * |
455 | * This call is used only by SPI master controller drivers, which are the | |
456 | * only ones directly touching chip registers. It's how they allocate | |
ba1a0513 | 457 | * an spi_master structure, prior to calling spi_register_master(). |
8ae12a0d DB |
458 | * |
459 | * This must be called from context that can sleep. It returns the SPI | |
460 | * master structure on success, else NULL. | |
461 | * | |
462 | * The caller is responsible for assigning the bus number and initializing | |
ba1a0513 | 463 | * the master's methods before calling spi_register_master(); and (after errors |
0c868461 | 464 | * adding the device) calling spi_master_put() to prevent a memory leak. |
8ae12a0d | 465 | */ |
e9d5a461 | 466 | struct spi_master *spi_alloc_master(struct device *dev, unsigned size) |
8ae12a0d DB |
467 | { |
468 | struct spi_master *master; | |
469 | ||
0c868461 DB |
470 | if (!dev) |
471 | return NULL; | |
472 | ||
e94b1766 | 473 | master = kzalloc(size + sizeof *master, GFP_KERNEL); |
8ae12a0d DB |
474 | if (!master) |
475 | return NULL; | |
476 | ||
49dce689 TJ |
477 | device_initialize(&master->dev); |
478 | master->dev.class = &spi_master_class; | |
479 | master->dev.parent = get_device(dev); | |
0c868461 | 480 | spi_master_set_devdata(master, &master[1]); |
8ae12a0d DB |
481 | |
482 | return master; | |
483 | } | |
484 | EXPORT_SYMBOL_GPL(spi_alloc_master); | |
485 | ||
486 | /** | |
487 | * spi_register_master - register SPI master controller | |
488 | * @master: initialized master, originally from spi_alloc_master() | |
33e34dc6 | 489 | * Context: can sleep |
8ae12a0d DB |
490 | * |
491 | * SPI master controllers connect to their drivers using some non-SPI bus, | |
492 | * such as the platform bus. The final stage of probe() in that code | |
493 | * includes calling spi_register_master() to hook up to this SPI bus glue. | |
494 | * | |
495 | * SPI controllers use board specific (often SOC specific) bus numbers, | |
496 | * and board-specific addressing for SPI devices combines those numbers | |
497 | * with chip select numbers. Since SPI does not directly support dynamic | |
498 | * device identification, boards need configuration tables telling which | |
499 | * chip is at which address. | |
500 | * | |
501 | * This must be called from context that can sleep. It returns zero on | |
502 | * success, else a negative error code (dropping the master's refcount). | |
0c868461 DB |
503 | * After a successful return, the caller is responsible for calling |
504 | * spi_unregister_master(). | |
8ae12a0d | 505 | */ |
e9d5a461 | 506 | int spi_register_master(struct spi_master *master) |
8ae12a0d | 507 | { |
e44a45ae | 508 | static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1); |
49dce689 | 509 | struct device *dev = master->dev.parent; |
8ae12a0d DB |
510 | int status = -ENODEV; |
511 | int dynamic = 0; | |
512 | ||
0c868461 DB |
513 | if (!dev) |
514 | return -ENODEV; | |
515 | ||
082c8cb4 DB |
516 | /* even if it's just one always-selected device, there must |
517 | * be at least one chipselect | |
518 | */ | |
519 | if (master->num_chipselect == 0) | |
520 | return -EINVAL; | |
521 | ||
8ae12a0d | 522 | /* convention: dynamically assigned bus IDs count down from the max */ |
a020ed75 | 523 | if (master->bus_num < 0) { |
082c8cb4 DB |
524 | /* FIXME switch to an IDR based scheme, something like |
525 | * I2C now uses, so we can't run out of "dynamic" IDs | |
526 | */ | |
8ae12a0d | 527 | master->bus_num = atomic_dec_return(&dyn_bus_id); |
b885244e | 528 | dynamic = 1; |
8ae12a0d DB |
529 | } |
530 | ||
cf32b71e ES |
531 | spin_lock_init(&master->bus_lock_spinlock); |
532 | mutex_init(&master->bus_lock_mutex); | |
533 | master->bus_lock_flag = 0; | |
534 | ||
8ae12a0d DB |
535 | /* register the device, then userspace will see it. |
536 | * registration fails if the bus ID is in use. | |
537 | */ | |
35f74fca | 538 | dev_set_name(&master->dev, "spi%u", master->bus_num); |
49dce689 | 539 | status = device_add(&master->dev); |
b885244e | 540 | if (status < 0) |
8ae12a0d | 541 | goto done; |
35f74fca | 542 | dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev), |
8ae12a0d DB |
543 | dynamic ? " (dynamic)" : ""); |
544 | ||
545 | /* populate children from any spi device tables */ | |
546 | scan_boardinfo(master); | |
547 | status = 0; | |
12b15e83 AG |
548 | |
549 | /* Register devices from the device tree */ | |
550 | of_register_spi_devices(master); | |
8ae12a0d DB |
551 | done: |
552 | return status; | |
553 | } | |
554 | EXPORT_SYMBOL_GPL(spi_register_master); | |
555 | ||
556 | ||
350d0076 | 557 | static int __unregister(struct device *dev, void *master_dev) |
8ae12a0d DB |
558 | { |
559 | /* note: before about 2.6.14-rc1 this would corrupt memory: */ | |
350d0076 AN |
560 | if (dev != master_dev) |
561 | spi_unregister_device(to_spi_device(dev)); | |
8ae12a0d DB |
562 | return 0; |
563 | } | |
564 | ||
565 | /** | |
566 | * spi_unregister_master - unregister SPI master controller | |
567 | * @master: the master being unregistered | |
33e34dc6 | 568 | * Context: can sleep |
8ae12a0d DB |
569 | * |
570 | * This call is used only by SPI master controller drivers, which are the | |
571 | * only ones directly touching chip registers. | |
572 | * | |
573 | * This must be called from context that can sleep. | |
574 | */ | |
575 | void spi_unregister_master(struct spi_master *master) | |
576 | { | |
89fc9a1a JG |
577 | int dummy; |
578 | ||
350d0076 AN |
579 | dummy = device_for_each_child(master->dev.parent, &master->dev, |
580 | __unregister); | |
49dce689 | 581 | device_unregister(&master->dev); |
8ae12a0d DB |
582 | } |
583 | EXPORT_SYMBOL_GPL(spi_unregister_master); | |
584 | ||
5ed2c832 DY |
585 | static int __spi_master_match(struct device *dev, void *data) |
586 | { | |
587 | struct spi_master *m; | |
588 | u16 *bus_num = data; | |
589 | ||
590 | m = container_of(dev, struct spi_master, dev); | |
591 | return m->bus_num == *bus_num; | |
592 | } | |
593 | ||
8ae12a0d DB |
594 | /** |
595 | * spi_busnum_to_master - look up master associated with bus_num | |
596 | * @bus_num: the master's bus number | |
33e34dc6 | 597 | * Context: can sleep |
8ae12a0d DB |
598 | * |
599 | * This call may be used with devices that are registered after | |
600 | * arch init time. It returns a refcounted pointer to the relevant | |
601 | * spi_master (which the caller must release), or NULL if there is | |
602 | * no such master registered. | |
603 | */ | |
604 | struct spi_master *spi_busnum_to_master(u16 bus_num) | |
605 | { | |
49dce689 | 606 | struct device *dev; |
1e9a51dc | 607 | struct spi_master *master = NULL; |
5ed2c832 | 608 | |
695794ae | 609 | dev = class_find_device(&spi_master_class, NULL, &bus_num, |
5ed2c832 DY |
610 | __spi_master_match); |
611 | if (dev) | |
612 | master = container_of(dev, struct spi_master, dev); | |
613 | /* reference got in class_find_device */ | |
1e9a51dc | 614 | return master; |
8ae12a0d DB |
615 | } |
616 | EXPORT_SYMBOL_GPL(spi_busnum_to_master); | |
617 | ||
618 | ||
619 | /*-------------------------------------------------------------------------*/ | |
620 | ||
7d077197 DB |
621 | /* Core methods for SPI master protocol drivers. Some of the |
622 | * other core methods are currently defined as inline functions. | |
623 | */ | |
624 | ||
625 | /** | |
626 | * spi_setup - setup SPI mode and clock rate | |
627 | * @spi: the device whose settings are being modified | |
628 | * Context: can sleep, and no requests are queued to the device | |
629 | * | |
630 | * SPI protocol drivers may need to update the transfer mode if the | |
631 | * device doesn't work with its default. They may likewise need | |
632 | * to update clock rates or word sizes from initial values. This function | |
633 | * changes those settings, and must be called from a context that can sleep. | |
634 | * Except for SPI_CS_HIGH, which takes effect immediately, the changes take | |
635 | * effect the next time the device is selected and data is transferred to | |
636 | * or from it. When this function returns, the spi device is deselected. | |
637 | * | |
638 | * Note that this call will fail if the protocol driver specifies an option | |
639 | * that the underlying controller or its driver does not support. For | |
640 | * example, not all hardware supports wire transfers using nine bit words, | |
641 | * LSB-first wire encoding, or active-high chipselects. | |
642 | */ | |
643 | int spi_setup(struct spi_device *spi) | |
644 | { | |
e7db06b5 | 645 | unsigned bad_bits; |
7d077197 DB |
646 | int status; |
647 | ||
e7db06b5 DB |
648 | /* help drivers fail *cleanly* when they need options |
649 | * that aren't supported with their current master | |
650 | */ | |
651 | bad_bits = spi->mode & ~spi->master->mode_bits; | |
652 | if (bad_bits) { | |
653 | dev_dbg(&spi->dev, "setup: unsupported mode bits %x\n", | |
654 | bad_bits); | |
655 | return -EINVAL; | |
656 | } | |
657 | ||
7d077197 DB |
658 | if (!spi->bits_per_word) |
659 | spi->bits_per_word = 8; | |
660 | ||
661 | status = spi->master->setup(spi); | |
662 | ||
663 | dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s" | |
664 | "%u bits/w, %u Hz max --> %d\n", | |
665 | (int) (spi->mode & (SPI_CPOL | SPI_CPHA)), | |
666 | (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "", | |
667 | (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "", | |
668 | (spi->mode & SPI_3WIRE) ? "3wire, " : "", | |
669 | (spi->mode & SPI_LOOP) ? "loopback, " : "", | |
670 | spi->bits_per_word, spi->max_speed_hz, | |
671 | status); | |
672 | ||
673 | return status; | |
674 | } | |
675 | EXPORT_SYMBOL_GPL(spi_setup); | |
676 | ||
cf32b71e ES |
677 | static int __spi_async(struct spi_device *spi, struct spi_message *message) |
678 | { | |
679 | struct spi_master *master = spi->master; | |
680 | ||
681 | /* Half-duplex links include original MicroWire, and ones with | |
682 | * only one data pin like SPI_3WIRE (switches direction) or where | |
683 | * either MOSI or MISO is missing. They can also be caused by | |
684 | * software limitations. | |
685 | */ | |
686 | if ((master->flags & SPI_MASTER_HALF_DUPLEX) | |
687 | || (spi->mode & SPI_3WIRE)) { | |
688 | struct spi_transfer *xfer; | |
689 | unsigned flags = master->flags; | |
690 | ||
691 | list_for_each_entry(xfer, &message->transfers, transfer_list) { | |
692 | if (xfer->rx_buf && xfer->tx_buf) | |
693 | return -EINVAL; | |
694 | if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf) | |
695 | return -EINVAL; | |
696 | if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf) | |
697 | return -EINVAL; | |
698 | } | |
699 | } | |
700 | ||
701 | message->spi = spi; | |
702 | message->status = -EINPROGRESS; | |
703 | return master->transfer(spi, message); | |
704 | } | |
705 | ||
568d0697 DB |
706 | /** |
707 | * spi_async - asynchronous SPI transfer | |
708 | * @spi: device with which data will be exchanged | |
709 | * @message: describes the data transfers, including completion callback | |
710 | * Context: any (irqs may be blocked, etc) | |
711 | * | |
712 | * This call may be used in_irq and other contexts which can't sleep, | |
713 | * as well as from task contexts which can sleep. | |
714 | * | |
715 | * The completion callback is invoked in a context which can't sleep. | |
716 | * Before that invocation, the value of message->status is undefined. | |
717 | * When the callback is issued, message->status holds either zero (to | |
718 | * indicate complete success) or a negative error code. After that | |
719 | * callback returns, the driver which issued the transfer request may | |
720 | * deallocate the associated memory; it's no longer in use by any SPI | |
721 | * core or controller driver code. | |
722 | * | |
723 | * Note that although all messages to a spi_device are handled in | |
724 | * FIFO order, messages may go to different devices in other orders. | |
725 | * Some device might be higher priority, or have various "hard" access | |
726 | * time requirements, for example. | |
727 | * | |
728 | * On detection of any fault during the transfer, processing of | |
729 | * the entire message is aborted, and the device is deselected. | |
730 | * Until returning from the associated message completion callback, | |
731 | * no other spi_message queued to that device will be processed. | |
732 | * (This rule applies equally to all the synchronous transfer calls, | |
733 | * which are wrappers around this core asynchronous primitive.) | |
734 | */ | |
735 | int spi_async(struct spi_device *spi, struct spi_message *message) | |
736 | { | |
737 | struct spi_master *master = spi->master; | |
cf32b71e ES |
738 | int ret; |
739 | unsigned long flags; | |
568d0697 | 740 | |
cf32b71e | 741 | spin_lock_irqsave(&master->bus_lock_spinlock, flags); |
568d0697 | 742 | |
cf32b71e ES |
743 | if (master->bus_lock_flag) |
744 | ret = -EBUSY; | |
745 | else | |
746 | ret = __spi_async(spi, message); | |
568d0697 | 747 | |
cf32b71e ES |
748 | spin_unlock_irqrestore(&master->bus_lock_spinlock, flags); |
749 | ||
750 | return ret; | |
568d0697 DB |
751 | } |
752 | EXPORT_SYMBOL_GPL(spi_async); | |
753 | ||
cf32b71e ES |
754 | /** |
755 | * spi_async_locked - version of spi_async with exclusive bus usage | |
756 | * @spi: device with which data will be exchanged | |
757 | * @message: describes the data transfers, including completion callback | |
758 | * Context: any (irqs may be blocked, etc) | |
759 | * | |
760 | * This call may be used in_irq and other contexts which can't sleep, | |
761 | * as well as from task contexts which can sleep. | |
762 | * | |
763 | * The completion callback is invoked in a context which can't sleep. | |
764 | * Before that invocation, the value of message->status is undefined. | |
765 | * When the callback is issued, message->status holds either zero (to | |
766 | * indicate complete success) or a negative error code. After that | |
767 | * callback returns, the driver which issued the transfer request may | |
768 | * deallocate the associated memory; it's no longer in use by any SPI | |
769 | * core or controller driver code. | |
770 | * | |
771 | * Note that although all messages to a spi_device are handled in | |
772 | * FIFO order, messages may go to different devices in other orders. | |
773 | * Some device might be higher priority, or have various "hard" access | |
774 | * time requirements, for example. | |
775 | * | |
776 | * On detection of any fault during the transfer, processing of | |
777 | * the entire message is aborted, and the device is deselected. | |
778 | * Until returning from the associated message completion callback, | |
779 | * no other spi_message queued to that device will be processed. | |
780 | * (This rule applies equally to all the synchronous transfer calls, | |
781 | * which are wrappers around this core asynchronous primitive.) | |
782 | */ | |
783 | int spi_async_locked(struct spi_device *spi, struct spi_message *message) | |
784 | { | |
785 | struct spi_master *master = spi->master; | |
786 | int ret; | |
787 | unsigned long flags; | |
788 | ||
789 | spin_lock_irqsave(&master->bus_lock_spinlock, flags); | |
790 | ||
791 | ret = __spi_async(spi, message); | |
792 | ||
793 | spin_unlock_irqrestore(&master->bus_lock_spinlock, flags); | |
794 | ||
795 | return ret; | |
796 | ||
797 | } | |
798 | EXPORT_SYMBOL_GPL(spi_async_locked); | |
799 | ||
7d077197 DB |
800 | |
801 | /*-------------------------------------------------------------------------*/ | |
802 | ||
803 | /* Utility methods for SPI master protocol drivers, layered on | |
804 | * top of the core. Some other utility methods are defined as | |
805 | * inline functions. | |
806 | */ | |
807 | ||
5d870c8e AM |
808 | static void spi_complete(void *arg) |
809 | { | |
810 | complete(arg); | |
811 | } | |
812 | ||
cf32b71e ES |
813 | static int __spi_sync(struct spi_device *spi, struct spi_message *message, |
814 | int bus_locked) | |
815 | { | |
816 | DECLARE_COMPLETION_ONSTACK(done); | |
817 | int status; | |
818 | struct spi_master *master = spi->master; | |
819 | ||
820 | message->complete = spi_complete; | |
821 | message->context = &done; | |
822 | ||
823 | if (!bus_locked) | |
824 | mutex_lock(&master->bus_lock_mutex); | |
825 | ||
826 | status = spi_async_locked(spi, message); | |
827 | ||
828 | if (!bus_locked) | |
829 | mutex_unlock(&master->bus_lock_mutex); | |
830 | ||
831 | if (status == 0) { | |
832 | wait_for_completion(&done); | |
833 | status = message->status; | |
834 | } | |
835 | message->context = NULL; | |
836 | return status; | |
837 | } | |
838 | ||
8ae12a0d DB |
839 | /** |
840 | * spi_sync - blocking/synchronous SPI data transfers | |
841 | * @spi: device with which data will be exchanged | |
842 | * @message: describes the data transfers | |
33e34dc6 | 843 | * Context: can sleep |
8ae12a0d DB |
844 | * |
845 | * This call may only be used from a context that may sleep. The sleep | |
846 | * is non-interruptible, and has no timeout. Low-overhead controller | |
847 | * drivers may DMA directly into and out of the message buffers. | |
848 | * | |
849 | * Note that the SPI device's chip select is active during the message, | |
850 | * and then is normally disabled between messages. Drivers for some | |
851 | * frequently-used devices may want to minimize costs of selecting a chip, | |
852 | * by leaving it selected in anticipation that the next message will go | |
853 | * to the same chip. (That may increase power usage.) | |
854 | * | |
0c868461 DB |
855 | * Also, the caller is guaranteeing that the memory associated with the |
856 | * message will not be freed before this call returns. | |
857 | * | |
9b938b74 | 858 | * It returns zero on success, else a negative error code. |
8ae12a0d DB |
859 | */ |
860 | int spi_sync(struct spi_device *spi, struct spi_message *message) | |
861 | { | |
cf32b71e | 862 | return __spi_sync(spi, message, 0); |
8ae12a0d DB |
863 | } |
864 | EXPORT_SYMBOL_GPL(spi_sync); | |
865 | ||
cf32b71e ES |
866 | /** |
867 | * spi_sync_locked - version of spi_sync with exclusive bus usage | |
868 | * @spi: device with which data will be exchanged | |
869 | * @message: describes the data transfers | |
870 | * Context: can sleep | |
871 | * | |
872 | * This call may only be used from a context that may sleep. The sleep | |
873 | * is non-interruptible, and has no timeout. Low-overhead controller | |
874 | * drivers may DMA directly into and out of the message buffers. | |
875 | * | |
876 | * This call should be used by drivers that require exclusive access to the | |
877 | * SPI bus. It has to be preceeded by a spi_bus_lock call. The SPI bus must | |
878 | * be released by a spi_bus_unlock call when the exclusive access is over. | |
879 | * | |
880 | * It returns zero on success, else a negative error code. | |
881 | */ | |
882 | int spi_sync_locked(struct spi_device *spi, struct spi_message *message) | |
883 | { | |
884 | return __spi_sync(spi, message, 1); | |
885 | } | |
886 | EXPORT_SYMBOL_GPL(spi_sync_locked); | |
887 | ||
888 | /** | |
889 | * spi_bus_lock - obtain a lock for exclusive SPI bus usage | |
890 | * @master: SPI bus master that should be locked for exclusive bus access | |
891 | * Context: can sleep | |
892 | * | |
893 | * This call may only be used from a context that may sleep. The sleep | |
894 | * is non-interruptible, and has no timeout. | |
895 | * | |
896 | * This call should be used by drivers that require exclusive access to the | |
897 | * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the | |
898 | * exclusive access is over. Data transfer must be done by spi_sync_locked | |
899 | * and spi_async_locked calls when the SPI bus lock is held. | |
900 | * | |
901 | * It returns zero on success, else a negative error code. | |
902 | */ | |
903 | int spi_bus_lock(struct spi_master *master) | |
904 | { | |
905 | unsigned long flags; | |
906 | ||
907 | mutex_lock(&master->bus_lock_mutex); | |
908 | ||
909 | spin_lock_irqsave(&master->bus_lock_spinlock, flags); | |
910 | master->bus_lock_flag = 1; | |
911 | spin_unlock_irqrestore(&master->bus_lock_spinlock, flags); | |
912 | ||
913 | /* mutex remains locked until spi_bus_unlock is called */ | |
914 | ||
915 | return 0; | |
916 | } | |
917 | EXPORT_SYMBOL_GPL(spi_bus_lock); | |
918 | ||
919 | /** | |
920 | * spi_bus_unlock - release the lock for exclusive SPI bus usage | |
921 | * @master: SPI bus master that was locked for exclusive bus access | |
922 | * Context: can sleep | |
923 | * | |
924 | * This call may only be used from a context that may sleep. The sleep | |
925 | * is non-interruptible, and has no timeout. | |
926 | * | |
927 | * This call releases an SPI bus lock previously obtained by an spi_bus_lock | |
928 | * call. | |
929 | * | |
930 | * It returns zero on success, else a negative error code. | |
931 | */ | |
932 | int spi_bus_unlock(struct spi_master *master) | |
933 | { | |
934 | master->bus_lock_flag = 0; | |
935 | ||
936 | mutex_unlock(&master->bus_lock_mutex); | |
937 | ||
938 | return 0; | |
939 | } | |
940 | EXPORT_SYMBOL_GPL(spi_bus_unlock); | |
941 | ||
a9948b61 DB |
942 | /* portable code must never pass more than 32 bytes */ |
943 | #define SPI_BUFSIZ max(32,SMP_CACHE_BYTES) | |
8ae12a0d DB |
944 | |
945 | static u8 *buf; | |
946 | ||
947 | /** | |
948 | * spi_write_then_read - SPI synchronous write followed by read | |
949 | * @spi: device with which data will be exchanged | |
950 | * @txbuf: data to be written (need not be dma-safe) | |
951 | * @n_tx: size of txbuf, in bytes | |
27570497 JP |
952 | * @rxbuf: buffer into which data will be read (need not be dma-safe) |
953 | * @n_rx: size of rxbuf, in bytes | |
33e34dc6 | 954 | * Context: can sleep |
8ae12a0d DB |
955 | * |
956 | * This performs a half duplex MicroWire style transaction with the | |
957 | * device, sending txbuf and then reading rxbuf. The return value | |
958 | * is zero for success, else a negative errno status code. | |
b885244e | 959 | * This call may only be used from a context that may sleep. |
8ae12a0d | 960 | * |
0c868461 | 961 | * Parameters to this routine are always copied using a small buffer; |
33e34dc6 DB |
962 | * portable code should never use this for more than 32 bytes. |
963 | * Performance-sensitive or bulk transfer code should instead use | |
0c868461 | 964 | * spi_{async,sync}() calls with dma-safe buffers. |
8ae12a0d DB |
965 | */ |
966 | int spi_write_then_read(struct spi_device *spi, | |
967 | const u8 *txbuf, unsigned n_tx, | |
968 | u8 *rxbuf, unsigned n_rx) | |
969 | { | |
068f4070 | 970 | static DEFINE_MUTEX(lock); |
8ae12a0d DB |
971 | |
972 | int status; | |
973 | struct spi_message message; | |
bdff549e | 974 | struct spi_transfer x[2]; |
8ae12a0d DB |
975 | u8 *local_buf; |
976 | ||
977 | /* Use preallocated DMA-safe buffer. We can't avoid copying here, | |
978 | * (as a pure convenience thing), but we can keep heap costs | |
979 | * out of the hot path ... | |
980 | */ | |
981 | if ((n_tx + n_rx) > SPI_BUFSIZ) | |
982 | return -EINVAL; | |
983 | ||
8275c642 | 984 | spi_message_init(&message); |
bdff549e DB |
985 | memset(x, 0, sizeof x); |
986 | if (n_tx) { | |
987 | x[0].len = n_tx; | |
988 | spi_message_add_tail(&x[0], &message); | |
989 | } | |
990 | if (n_rx) { | |
991 | x[1].len = n_rx; | |
992 | spi_message_add_tail(&x[1], &message); | |
993 | } | |
8275c642 | 994 | |
8ae12a0d | 995 | /* ... unless someone else is using the pre-allocated buffer */ |
068f4070 | 996 | if (!mutex_trylock(&lock)) { |
8ae12a0d DB |
997 | local_buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL); |
998 | if (!local_buf) | |
999 | return -ENOMEM; | |
1000 | } else | |
1001 | local_buf = buf; | |
1002 | ||
8ae12a0d | 1003 | memcpy(local_buf, txbuf, n_tx); |
bdff549e DB |
1004 | x[0].tx_buf = local_buf; |
1005 | x[1].rx_buf = local_buf + n_tx; | |
8ae12a0d DB |
1006 | |
1007 | /* do the i/o */ | |
8ae12a0d | 1008 | status = spi_sync(spi, &message); |
9b938b74 | 1009 | if (status == 0) |
bdff549e | 1010 | memcpy(rxbuf, x[1].rx_buf, n_rx); |
8ae12a0d | 1011 | |
bdff549e | 1012 | if (x[0].tx_buf == buf) |
068f4070 | 1013 | mutex_unlock(&lock); |
8ae12a0d DB |
1014 | else |
1015 | kfree(local_buf); | |
1016 | ||
1017 | return status; | |
1018 | } | |
1019 | EXPORT_SYMBOL_GPL(spi_write_then_read); | |
1020 | ||
1021 | /*-------------------------------------------------------------------------*/ | |
1022 | ||
1023 | static int __init spi_init(void) | |
1024 | { | |
b885244e DB |
1025 | int status; |
1026 | ||
e94b1766 | 1027 | buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL); |
b885244e DB |
1028 | if (!buf) { |
1029 | status = -ENOMEM; | |
1030 | goto err0; | |
1031 | } | |
1032 | ||
1033 | status = bus_register(&spi_bus_type); | |
1034 | if (status < 0) | |
1035 | goto err1; | |
8ae12a0d | 1036 | |
b885244e DB |
1037 | status = class_register(&spi_master_class); |
1038 | if (status < 0) | |
1039 | goto err2; | |
8ae12a0d | 1040 | return 0; |
b885244e DB |
1041 | |
1042 | err2: | |
1043 | bus_unregister(&spi_bus_type); | |
1044 | err1: | |
1045 | kfree(buf); | |
1046 | buf = NULL; | |
1047 | err0: | |
1048 | return status; | |
8ae12a0d | 1049 | } |
b885244e | 1050 | |
8ae12a0d DB |
1051 | /* board_info is normally registered in arch_initcall(), |
1052 | * but even essential drivers wait till later | |
b885244e DB |
1053 | * |
1054 | * REVISIT only boardinfo really needs static linking. the rest (device and | |
1055 | * driver registration) _could_ be dynamically linked (modular) ... costs | |
1056 | * include needing to have boardinfo data structures be much more public. | |
8ae12a0d | 1057 | */ |
673c0c00 | 1058 | postcore_initcall(spi_init); |
8ae12a0d | 1059 |