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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> |
2b7a32f7 | 26 | #include <linux/of_device.h> |
5a0e3ad6 | 27 | #include <linux/slab.h> |
e0626e38 | 28 | #include <linux/mod_devicetable.h> |
8ae12a0d | 29 | #include <linux/spi/spi.h> |
12b15e83 | 30 | #include <linux/of_spi.h> |
8ae12a0d DB |
31 | |
32 | ||
b885244e DB |
33 | /* SPI bustype and spi_master class are registered after board init code |
34 | * provides the SPI device tables, ensuring that both are present by the | |
35 | * time controller driver registration causes spi_devices to "enumerate". | |
8ae12a0d DB |
36 | */ |
37 | static void spidev_release(struct device *dev) | |
38 | { | |
0ffa0285 | 39 | struct spi_device *spi = to_spi_device(dev); |
8ae12a0d DB |
40 | |
41 | /* spi masters may cleanup for released devices */ | |
42 | if (spi->master->cleanup) | |
43 | spi->master->cleanup(spi); | |
44 | ||
0c868461 | 45 | spi_master_put(spi->master); |
07a389fe | 46 | kfree(spi); |
8ae12a0d DB |
47 | } |
48 | ||
49 | static ssize_t | |
50 | modalias_show(struct device *dev, struct device_attribute *a, char *buf) | |
51 | { | |
52 | const struct spi_device *spi = to_spi_device(dev); | |
53 | ||
35f74fca | 54 | return sprintf(buf, "%s\n", spi->modalias); |
8ae12a0d DB |
55 | } |
56 | ||
57 | static struct device_attribute spi_dev_attrs[] = { | |
58 | __ATTR_RO(modalias), | |
59 | __ATTR_NULL, | |
60 | }; | |
61 | ||
62 | /* modalias support makes "modprobe $MODALIAS" new-style hotplug work, | |
63 | * and the sysfs version makes coldplug work too. | |
64 | */ | |
65 | ||
75368bf6 AV |
66 | static const struct spi_device_id *spi_match_id(const struct spi_device_id *id, |
67 | const struct spi_device *sdev) | |
68 | { | |
69 | while (id->name[0]) { | |
70 | if (!strcmp(sdev->modalias, id->name)) | |
71 | return id; | |
72 | id++; | |
73 | } | |
74 | return NULL; | |
75 | } | |
76 | ||
77 | const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev) | |
78 | { | |
79 | const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver); | |
80 | ||
81 | return spi_match_id(sdrv->id_table, sdev); | |
82 | } | |
83 | EXPORT_SYMBOL_GPL(spi_get_device_id); | |
84 | ||
8ae12a0d DB |
85 | static int spi_match_device(struct device *dev, struct device_driver *drv) |
86 | { | |
87 | const struct spi_device *spi = to_spi_device(dev); | |
75368bf6 AV |
88 | const struct spi_driver *sdrv = to_spi_driver(drv); |
89 | ||
2b7a32f7 SA |
90 | /* Attempt an OF style match */ |
91 | if (of_driver_match_device(dev, drv)) | |
92 | return 1; | |
93 | ||
75368bf6 AV |
94 | if (sdrv->id_table) |
95 | return !!spi_match_id(sdrv->id_table, spi); | |
8ae12a0d | 96 | |
35f74fca | 97 | return strcmp(spi->modalias, drv->name) == 0; |
8ae12a0d DB |
98 | } |
99 | ||
7eff2e7a | 100 | static int spi_uevent(struct device *dev, struct kobj_uevent_env *env) |
8ae12a0d DB |
101 | { |
102 | const struct spi_device *spi = to_spi_device(dev); | |
103 | ||
e0626e38 | 104 | add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias); |
8ae12a0d DB |
105 | return 0; |
106 | } | |
107 | ||
108 | #ifdef CONFIG_PM | |
109 | ||
8ae12a0d DB |
110 | static int spi_suspend(struct device *dev, pm_message_t message) |
111 | { | |
3c72426f | 112 | int value = 0; |
b885244e | 113 | struct spi_driver *drv = to_spi_driver(dev->driver); |
8ae12a0d | 114 | |
8ae12a0d | 115 | /* suspend will stop irqs and dma; no more i/o */ |
3c72426f DB |
116 | if (drv) { |
117 | if (drv->suspend) | |
118 | value = drv->suspend(to_spi_device(dev), message); | |
119 | else | |
120 | dev_dbg(dev, "... can't suspend\n"); | |
121 | } | |
8ae12a0d DB |
122 | return value; |
123 | } | |
124 | ||
125 | static int spi_resume(struct device *dev) | |
126 | { | |
3c72426f | 127 | int value = 0; |
b885244e | 128 | struct spi_driver *drv = to_spi_driver(dev->driver); |
8ae12a0d | 129 | |
8ae12a0d | 130 | /* resume may restart the i/o queue */ |
3c72426f DB |
131 | if (drv) { |
132 | if (drv->resume) | |
133 | value = drv->resume(to_spi_device(dev)); | |
134 | else | |
135 | dev_dbg(dev, "... can't resume\n"); | |
136 | } | |
8ae12a0d DB |
137 | return value; |
138 | } | |
139 | ||
140 | #else | |
141 | #define spi_suspend NULL | |
142 | #define spi_resume NULL | |
143 | #endif | |
144 | ||
145 | struct bus_type spi_bus_type = { | |
146 | .name = "spi", | |
147 | .dev_attrs = spi_dev_attrs, | |
148 | .match = spi_match_device, | |
149 | .uevent = spi_uevent, | |
150 | .suspend = spi_suspend, | |
151 | .resume = spi_resume, | |
152 | }; | |
153 | EXPORT_SYMBOL_GPL(spi_bus_type); | |
154 | ||
b885244e DB |
155 | |
156 | static int spi_drv_probe(struct device *dev) | |
157 | { | |
158 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); | |
159 | ||
160 | return sdrv->probe(to_spi_device(dev)); | |
161 | } | |
162 | ||
163 | static int spi_drv_remove(struct device *dev) | |
164 | { | |
165 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); | |
166 | ||
167 | return sdrv->remove(to_spi_device(dev)); | |
168 | } | |
169 | ||
170 | static void spi_drv_shutdown(struct device *dev) | |
171 | { | |
172 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); | |
173 | ||
174 | sdrv->shutdown(to_spi_device(dev)); | |
175 | } | |
176 | ||
33e34dc6 DB |
177 | /** |
178 | * spi_register_driver - register a SPI driver | |
179 | * @sdrv: the driver to register | |
180 | * Context: can sleep | |
181 | */ | |
b885244e DB |
182 | int spi_register_driver(struct spi_driver *sdrv) |
183 | { | |
184 | sdrv->driver.bus = &spi_bus_type; | |
185 | if (sdrv->probe) | |
186 | sdrv->driver.probe = spi_drv_probe; | |
187 | if (sdrv->remove) | |
188 | sdrv->driver.remove = spi_drv_remove; | |
189 | if (sdrv->shutdown) | |
190 | sdrv->driver.shutdown = spi_drv_shutdown; | |
191 | return driver_register(&sdrv->driver); | |
192 | } | |
193 | EXPORT_SYMBOL_GPL(spi_register_driver); | |
194 | ||
8ae12a0d DB |
195 | /*-------------------------------------------------------------------------*/ |
196 | ||
197 | /* SPI devices should normally not be created by SPI device drivers; that | |
198 | * would make them board-specific. Similarly with SPI master drivers. | |
199 | * Device registration normally goes into like arch/.../mach.../board-YYY.c | |
200 | * with other readonly (flashable) information about mainboard devices. | |
201 | */ | |
202 | ||
203 | struct boardinfo { | |
204 | struct list_head list; | |
205 | unsigned n_board_info; | |
206 | struct spi_board_info board_info[0]; | |
207 | }; | |
208 | ||
209 | static LIST_HEAD(board_list); | |
94040828 | 210 | static DEFINE_MUTEX(board_lock); |
8ae12a0d | 211 | |
dc87c98e GL |
212 | /** |
213 | * spi_alloc_device - Allocate a new SPI device | |
214 | * @master: Controller to which device is connected | |
215 | * Context: can sleep | |
216 | * | |
217 | * Allows a driver to allocate and initialize a spi_device without | |
218 | * registering it immediately. This allows a driver to directly | |
219 | * fill the spi_device with device parameters before calling | |
220 | * spi_add_device() on it. | |
221 | * | |
222 | * Caller is responsible to call spi_add_device() on the returned | |
223 | * spi_device structure to add it to the SPI master. If the caller | |
224 | * needs to discard the spi_device without adding it, then it should | |
225 | * call spi_dev_put() on it. | |
226 | * | |
227 | * Returns a pointer to the new device, or NULL. | |
228 | */ | |
229 | struct spi_device *spi_alloc_device(struct spi_master *master) | |
230 | { | |
231 | struct spi_device *spi; | |
232 | struct device *dev = master->dev.parent; | |
233 | ||
234 | if (!spi_master_get(master)) | |
235 | return NULL; | |
236 | ||
237 | spi = kzalloc(sizeof *spi, GFP_KERNEL); | |
238 | if (!spi) { | |
239 | dev_err(dev, "cannot alloc spi_device\n"); | |
240 | spi_master_put(master); | |
241 | return NULL; | |
242 | } | |
243 | ||
244 | spi->master = master; | |
245 | spi->dev.parent = dev; | |
246 | spi->dev.bus = &spi_bus_type; | |
247 | spi->dev.release = spidev_release; | |
248 | device_initialize(&spi->dev); | |
249 | return spi; | |
250 | } | |
251 | EXPORT_SYMBOL_GPL(spi_alloc_device); | |
252 | ||
253 | /** | |
254 | * spi_add_device - Add spi_device allocated with spi_alloc_device | |
255 | * @spi: spi_device to register | |
256 | * | |
257 | * Companion function to spi_alloc_device. Devices allocated with | |
258 | * spi_alloc_device can be added onto the spi bus with this function. | |
259 | * | |
e48880e0 | 260 | * Returns 0 on success; negative errno on failure |
dc87c98e GL |
261 | */ |
262 | int spi_add_device(struct spi_device *spi) | |
263 | { | |
e48880e0 | 264 | static DEFINE_MUTEX(spi_add_lock); |
dc87c98e | 265 | struct device *dev = spi->master->dev.parent; |
8ec130a0 | 266 | struct device *d; |
dc87c98e GL |
267 | int status; |
268 | ||
269 | /* Chipselects are numbered 0..max; validate. */ | |
270 | if (spi->chip_select >= spi->master->num_chipselect) { | |
271 | dev_err(dev, "cs%d >= max %d\n", | |
272 | spi->chip_select, | |
273 | spi->master->num_chipselect); | |
274 | return -EINVAL; | |
275 | } | |
276 | ||
277 | /* Set the bus ID string */ | |
35f74fca | 278 | dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev), |
dc87c98e GL |
279 | spi->chip_select); |
280 | ||
e48880e0 DB |
281 | |
282 | /* We need to make sure there's no other device with this | |
283 | * chipselect **BEFORE** we call setup(), else we'll trash | |
284 | * its configuration. Lock against concurrent add() calls. | |
285 | */ | |
286 | mutex_lock(&spi_add_lock); | |
287 | ||
8ec130a0 RT |
288 | d = bus_find_device_by_name(&spi_bus_type, NULL, dev_name(&spi->dev)); |
289 | if (d != NULL) { | |
e48880e0 DB |
290 | dev_err(dev, "chipselect %d already in use\n", |
291 | spi->chip_select); | |
8ec130a0 | 292 | put_device(d); |
e48880e0 DB |
293 | status = -EBUSY; |
294 | goto done; | |
295 | } | |
296 | ||
297 | /* Drivers may modify this initial i/o setup, but will | |
298 | * normally rely on the device being setup. Devices | |
299 | * using SPI_CS_HIGH can't coexist well otherwise... | |
300 | */ | |
7d077197 | 301 | status = spi_setup(spi); |
dc87c98e GL |
302 | if (status < 0) { |
303 | dev_err(dev, "can't %s %s, status %d\n", | |
35f74fca | 304 | "setup", dev_name(&spi->dev), status); |
e48880e0 | 305 | goto done; |
dc87c98e GL |
306 | } |
307 | ||
e48880e0 | 308 | /* Device may be bound to an active driver when this returns */ |
dc87c98e | 309 | status = device_add(&spi->dev); |
e48880e0 | 310 | if (status < 0) |
dc87c98e | 311 | dev_err(dev, "can't %s %s, status %d\n", |
35f74fca | 312 | "add", dev_name(&spi->dev), status); |
e48880e0 | 313 | else |
35f74fca | 314 | dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev)); |
dc87c98e | 315 | |
e48880e0 DB |
316 | done: |
317 | mutex_unlock(&spi_add_lock); | |
318 | return status; | |
dc87c98e GL |
319 | } |
320 | EXPORT_SYMBOL_GPL(spi_add_device); | |
8ae12a0d | 321 | |
33e34dc6 DB |
322 | /** |
323 | * spi_new_device - instantiate one new SPI device | |
324 | * @master: Controller to which device is connected | |
325 | * @chip: Describes the SPI device | |
326 | * Context: can sleep | |
327 | * | |
328 | * On typical mainboards, this is purely internal; and it's not needed | |
8ae12a0d DB |
329 | * after board init creates the hard-wired devices. Some development |
330 | * platforms may not be able to use spi_register_board_info though, and | |
331 | * this is exported so that for example a USB or parport based adapter | |
332 | * driver could add devices (which it would learn about out-of-band). | |
082c8cb4 DB |
333 | * |
334 | * Returns the new device, or NULL. | |
8ae12a0d | 335 | */ |
e9d5a461 AB |
336 | struct spi_device *spi_new_device(struct spi_master *master, |
337 | struct spi_board_info *chip) | |
8ae12a0d DB |
338 | { |
339 | struct spi_device *proxy; | |
8ae12a0d DB |
340 | int status; |
341 | ||
082c8cb4 DB |
342 | /* NOTE: caller did any chip->bus_num checks necessary. |
343 | * | |
344 | * Also, unless we change the return value convention to use | |
345 | * error-or-pointer (not NULL-or-pointer), troubleshootability | |
346 | * suggests syslogged diagnostics are best here (ugh). | |
347 | */ | |
348 | ||
dc87c98e GL |
349 | proxy = spi_alloc_device(master); |
350 | if (!proxy) | |
8ae12a0d DB |
351 | return NULL; |
352 | ||
102eb975 GL |
353 | WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias)); |
354 | ||
8ae12a0d DB |
355 | proxy->chip_select = chip->chip_select; |
356 | proxy->max_speed_hz = chip->max_speed_hz; | |
980a01c9 | 357 | proxy->mode = chip->mode; |
8ae12a0d | 358 | proxy->irq = chip->irq; |
102eb975 | 359 | strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias)); |
8ae12a0d DB |
360 | proxy->dev.platform_data = (void *) chip->platform_data; |
361 | proxy->controller_data = chip->controller_data; | |
362 | proxy->controller_state = NULL; | |
8ae12a0d | 363 | |
dc87c98e | 364 | status = spi_add_device(proxy); |
8ae12a0d | 365 | if (status < 0) { |
dc87c98e GL |
366 | spi_dev_put(proxy); |
367 | return NULL; | |
8ae12a0d DB |
368 | } |
369 | ||
8ae12a0d DB |
370 | return proxy; |
371 | } | |
372 | EXPORT_SYMBOL_GPL(spi_new_device); | |
373 | ||
33e34dc6 DB |
374 | /** |
375 | * spi_register_board_info - register SPI devices for a given board | |
376 | * @info: array of chip descriptors | |
377 | * @n: how many descriptors are provided | |
378 | * Context: can sleep | |
379 | * | |
8ae12a0d DB |
380 | * Board-specific early init code calls this (probably during arch_initcall) |
381 | * with segments of the SPI device table. Any device nodes are created later, | |
382 | * after the relevant parent SPI controller (bus_num) is defined. We keep | |
383 | * this table of devices forever, so that reloading a controller driver will | |
384 | * not make Linux forget about these hard-wired devices. | |
385 | * | |
386 | * Other code can also call this, e.g. a particular add-on board might provide | |
387 | * SPI devices through its expansion connector, so code initializing that board | |
388 | * would naturally declare its SPI devices. | |
389 | * | |
390 | * The board info passed can safely be __initdata ... but be careful of | |
391 | * any embedded pointers (platform_data, etc), they're copied as-is. | |
392 | */ | |
393 | int __init | |
394 | spi_register_board_info(struct spi_board_info const *info, unsigned n) | |
395 | { | |
396 | struct boardinfo *bi; | |
397 | ||
b885244e | 398 | bi = kmalloc(sizeof(*bi) + n * sizeof *info, GFP_KERNEL); |
8ae12a0d DB |
399 | if (!bi) |
400 | return -ENOMEM; | |
401 | bi->n_board_info = n; | |
b885244e | 402 | memcpy(bi->board_info, info, n * sizeof *info); |
8ae12a0d | 403 | |
94040828 | 404 | mutex_lock(&board_lock); |
8ae12a0d | 405 | list_add_tail(&bi->list, &board_list); |
94040828 | 406 | mutex_unlock(&board_lock); |
8ae12a0d DB |
407 | return 0; |
408 | } | |
8ae12a0d DB |
409 | |
410 | /* FIXME someone should add support for a __setup("spi", ...) that | |
411 | * creates board info from kernel command lines | |
412 | */ | |
413 | ||
149a6501 | 414 | static void scan_boardinfo(struct spi_master *master) |
8ae12a0d DB |
415 | { |
416 | struct boardinfo *bi; | |
8ae12a0d | 417 | |
94040828 | 418 | mutex_lock(&board_lock); |
8ae12a0d DB |
419 | list_for_each_entry(bi, &board_list, list) { |
420 | struct spi_board_info *chip = bi->board_info; | |
421 | unsigned n; | |
422 | ||
423 | for (n = bi->n_board_info; n > 0; n--, chip++) { | |
424 | if (chip->bus_num != master->bus_num) | |
425 | continue; | |
082c8cb4 DB |
426 | /* NOTE: this relies on spi_new_device to |
427 | * issue diagnostics when given bogus inputs | |
8ae12a0d | 428 | */ |
8ae12a0d DB |
429 | (void) spi_new_device(master, chip); |
430 | } | |
431 | } | |
94040828 | 432 | mutex_unlock(&board_lock); |
8ae12a0d DB |
433 | } |
434 | ||
435 | /*-------------------------------------------------------------------------*/ | |
436 | ||
49dce689 | 437 | static void spi_master_release(struct device *dev) |
8ae12a0d DB |
438 | { |
439 | struct spi_master *master; | |
440 | ||
49dce689 | 441 | master = container_of(dev, struct spi_master, dev); |
8ae12a0d DB |
442 | kfree(master); |
443 | } | |
444 | ||
445 | static struct class spi_master_class = { | |
446 | .name = "spi_master", | |
447 | .owner = THIS_MODULE, | |
49dce689 | 448 | .dev_release = spi_master_release, |
8ae12a0d DB |
449 | }; |
450 | ||
451 | ||
452 | /** | |
453 | * spi_alloc_master - allocate SPI master controller | |
454 | * @dev: the controller, possibly using the platform_bus | |
33e34dc6 | 455 | * @size: how much zeroed driver-private data to allocate; the pointer to this |
49dce689 | 456 | * memory is in the driver_data field of the returned device, |
0c868461 | 457 | * accessible with spi_master_get_devdata(). |
33e34dc6 | 458 | * Context: can sleep |
8ae12a0d DB |
459 | * |
460 | * This call is used only by SPI master controller drivers, which are the | |
461 | * only ones directly touching chip registers. It's how they allocate | |
ba1a0513 | 462 | * an spi_master structure, prior to calling spi_register_master(). |
8ae12a0d DB |
463 | * |
464 | * This must be called from context that can sleep. It returns the SPI | |
465 | * master structure on success, else NULL. | |
466 | * | |
467 | * The caller is responsible for assigning the bus number and initializing | |
ba1a0513 | 468 | * the master's methods before calling spi_register_master(); and (after errors |
0c868461 | 469 | * adding the device) calling spi_master_put() to prevent a memory leak. |
8ae12a0d | 470 | */ |
e9d5a461 | 471 | struct spi_master *spi_alloc_master(struct device *dev, unsigned size) |
8ae12a0d DB |
472 | { |
473 | struct spi_master *master; | |
474 | ||
0c868461 DB |
475 | if (!dev) |
476 | return NULL; | |
477 | ||
e94b1766 | 478 | master = kzalloc(size + sizeof *master, GFP_KERNEL); |
8ae12a0d DB |
479 | if (!master) |
480 | return NULL; | |
481 | ||
49dce689 TJ |
482 | device_initialize(&master->dev); |
483 | master->dev.class = &spi_master_class; | |
484 | master->dev.parent = get_device(dev); | |
0c868461 | 485 | spi_master_set_devdata(master, &master[1]); |
8ae12a0d DB |
486 | |
487 | return master; | |
488 | } | |
489 | EXPORT_SYMBOL_GPL(spi_alloc_master); | |
490 | ||
491 | /** | |
492 | * spi_register_master - register SPI master controller | |
493 | * @master: initialized master, originally from spi_alloc_master() | |
33e34dc6 | 494 | * Context: can sleep |
8ae12a0d DB |
495 | * |
496 | * SPI master controllers connect to their drivers using some non-SPI bus, | |
497 | * such as the platform bus. The final stage of probe() in that code | |
498 | * includes calling spi_register_master() to hook up to this SPI bus glue. | |
499 | * | |
500 | * SPI controllers use board specific (often SOC specific) bus numbers, | |
501 | * and board-specific addressing for SPI devices combines those numbers | |
502 | * with chip select numbers. Since SPI does not directly support dynamic | |
503 | * device identification, boards need configuration tables telling which | |
504 | * chip is at which address. | |
505 | * | |
506 | * This must be called from context that can sleep. It returns zero on | |
507 | * success, else a negative error code (dropping the master's refcount). | |
0c868461 DB |
508 | * After a successful return, the caller is responsible for calling |
509 | * spi_unregister_master(). | |
8ae12a0d | 510 | */ |
e9d5a461 | 511 | int spi_register_master(struct spi_master *master) |
8ae12a0d | 512 | { |
e44a45ae | 513 | static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1); |
49dce689 | 514 | struct device *dev = master->dev.parent; |
8ae12a0d DB |
515 | int status = -ENODEV; |
516 | int dynamic = 0; | |
517 | ||
0c868461 DB |
518 | if (!dev) |
519 | return -ENODEV; | |
520 | ||
082c8cb4 DB |
521 | /* even if it's just one always-selected device, there must |
522 | * be at least one chipselect | |
523 | */ | |
524 | if (master->num_chipselect == 0) | |
525 | return -EINVAL; | |
526 | ||
8ae12a0d | 527 | /* convention: dynamically assigned bus IDs count down from the max */ |
a020ed75 | 528 | if (master->bus_num < 0) { |
082c8cb4 DB |
529 | /* FIXME switch to an IDR based scheme, something like |
530 | * I2C now uses, so we can't run out of "dynamic" IDs | |
531 | */ | |
8ae12a0d | 532 | master->bus_num = atomic_dec_return(&dyn_bus_id); |
b885244e | 533 | dynamic = 1; |
8ae12a0d DB |
534 | } |
535 | ||
cf32b71e ES |
536 | spin_lock_init(&master->bus_lock_spinlock); |
537 | mutex_init(&master->bus_lock_mutex); | |
538 | master->bus_lock_flag = 0; | |
539 | ||
8ae12a0d DB |
540 | /* register the device, then userspace will see it. |
541 | * registration fails if the bus ID is in use. | |
542 | */ | |
35f74fca | 543 | dev_set_name(&master->dev, "spi%u", master->bus_num); |
49dce689 | 544 | status = device_add(&master->dev); |
b885244e | 545 | if (status < 0) |
8ae12a0d | 546 | goto done; |
35f74fca | 547 | dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev), |
8ae12a0d DB |
548 | dynamic ? " (dynamic)" : ""); |
549 | ||
550 | /* populate children from any spi device tables */ | |
551 | scan_boardinfo(master); | |
552 | status = 0; | |
12b15e83 AG |
553 | |
554 | /* Register devices from the device tree */ | |
555 | of_register_spi_devices(master); | |
8ae12a0d DB |
556 | done: |
557 | return status; | |
558 | } | |
559 | EXPORT_SYMBOL_GPL(spi_register_master); | |
560 | ||
561 | ||
34860089 | 562 | static int __unregister(struct device *dev, void *null) |
8ae12a0d | 563 | { |
34860089 | 564 | spi_unregister_device(to_spi_device(dev)); |
8ae12a0d DB |
565 | return 0; |
566 | } | |
567 | ||
568 | /** | |
569 | * spi_unregister_master - unregister SPI master controller | |
570 | * @master: the master being unregistered | |
33e34dc6 | 571 | * Context: can sleep |
8ae12a0d DB |
572 | * |
573 | * This call is used only by SPI master controller drivers, which are the | |
574 | * only ones directly touching chip registers. | |
575 | * | |
576 | * This must be called from context that can sleep. | |
577 | */ | |
578 | void spi_unregister_master(struct spi_master *master) | |
579 | { | |
89fc9a1a JG |
580 | int dummy; |
581 | ||
34860089 | 582 | dummy = device_for_each_child(&master->dev, NULL, __unregister); |
49dce689 | 583 | device_unregister(&master->dev); |
8ae12a0d DB |
584 | } |
585 | EXPORT_SYMBOL_GPL(spi_unregister_master); | |
586 | ||
5ed2c832 DY |
587 | static int __spi_master_match(struct device *dev, void *data) |
588 | { | |
589 | struct spi_master *m; | |
590 | u16 *bus_num = data; | |
591 | ||
592 | m = container_of(dev, struct spi_master, dev); | |
593 | return m->bus_num == *bus_num; | |
594 | } | |
595 | ||
8ae12a0d DB |
596 | /** |
597 | * spi_busnum_to_master - look up master associated with bus_num | |
598 | * @bus_num: the master's bus number | |
33e34dc6 | 599 | * Context: can sleep |
8ae12a0d DB |
600 | * |
601 | * This call may be used with devices that are registered after | |
602 | * arch init time. It returns a refcounted pointer to the relevant | |
603 | * spi_master (which the caller must release), or NULL if there is | |
604 | * no such master registered. | |
605 | */ | |
606 | struct spi_master *spi_busnum_to_master(u16 bus_num) | |
607 | { | |
49dce689 | 608 | struct device *dev; |
1e9a51dc | 609 | struct spi_master *master = NULL; |
5ed2c832 | 610 | |
695794ae | 611 | dev = class_find_device(&spi_master_class, NULL, &bus_num, |
5ed2c832 DY |
612 | __spi_master_match); |
613 | if (dev) | |
614 | master = container_of(dev, struct spi_master, dev); | |
615 | /* reference got in class_find_device */ | |
1e9a51dc | 616 | return master; |
8ae12a0d DB |
617 | } |
618 | EXPORT_SYMBOL_GPL(spi_busnum_to_master); | |
619 | ||
620 | ||
621 | /*-------------------------------------------------------------------------*/ | |
622 | ||
7d077197 DB |
623 | /* Core methods for SPI master protocol drivers. Some of the |
624 | * other core methods are currently defined as inline functions. | |
625 | */ | |
626 | ||
627 | /** | |
628 | * spi_setup - setup SPI mode and clock rate | |
629 | * @spi: the device whose settings are being modified | |
630 | * Context: can sleep, and no requests are queued to the device | |
631 | * | |
632 | * SPI protocol drivers may need to update the transfer mode if the | |
633 | * device doesn't work with its default. They may likewise need | |
634 | * to update clock rates or word sizes from initial values. This function | |
635 | * changes those settings, and must be called from a context that can sleep. | |
636 | * Except for SPI_CS_HIGH, which takes effect immediately, the changes take | |
637 | * effect the next time the device is selected and data is transferred to | |
638 | * or from it. When this function returns, the spi device is deselected. | |
639 | * | |
640 | * Note that this call will fail if the protocol driver specifies an option | |
641 | * that the underlying controller or its driver does not support. For | |
642 | * example, not all hardware supports wire transfers using nine bit words, | |
643 | * LSB-first wire encoding, or active-high chipselects. | |
644 | */ | |
645 | int spi_setup(struct spi_device *spi) | |
646 | { | |
e7db06b5 | 647 | unsigned bad_bits; |
7d077197 DB |
648 | int status; |
649 | ||
e7db06b5 DB |
650 | /* help drivers fail *cleanly* when they need options |
651 | * that aren't supported with their current master | |
652 | */ | |
653 | bad_bits = spi->mode & ~spi->master->mode_bits; | |
654 | if (bad_bits) { | |
655 | dev_dbg(&spi->dev, "setup: unsupported mode bits %x\n", | |
656 | bad_bits); | |
657 | return -EINVAL; | |
658 | } | |
659 | ||
7d077197 DB |
660 | if (!spi->bits_per_word) |
661 | spi->bits_per_word = 8; | |
662 | ||
663 | status = spi->master->setup(spi); | |
664 | ||
665 | dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s" | |
666 | "%u bits/w, %u Hz max --> %d\n", | |
667 | (int) (spi->mode & (SPI_CPOL | SPI_CPHA)), | |
668 | (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "", | |
669 | (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "", | |
670 | (spi->mode & SPI_3WIRE) ? "3wire, " : "", | |
671 | (spi->mode & SPI_LOOP) ? "loopback, " : "", | |
672 | spi->bits_per_word, spi->max_speed_hz, | |
673 | status); | |
674 | ||
675 | return status; | |
676 | } | |
677 | EXPORT_SYMBOL_GPL(spi_setup); | |
678 | ||
cf32b71e ES |
679 | static int __spi_async(struct spi_device *spi, struct spi_message *message) |
680 | { | |
681 | struct spi_master *master = spi->master; | |
682 | ||
683 | /* Half-duplex links include original MicroWire, and ones with | |
684 | * only one data pin like SPI_3WIRE (switches direction) or where | |
685 | * either MOSI or MISO is missing. They can also be caused by | |
686 | * software limitations. | |
687 | */ | |
688 | if ((master->flags & SPI_MASTER_HALF_DUPLEX) | |
689 | || (spi->mode & SPI_3WIRE)) { | |
690 | struct spi_transfer *xfer; | |
691 | unsigned flags = master->flags; | |
692 | ||
693 | list_for_each_entry(xfer, &message->transfers, transfer_list) { | |
694 | if (xfer->rx_buf && xfer->tx_buf) | |
695 | return -EINVAL; | |
696 | if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf) | |
697 | return -EINVAL; | |
698 | if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf) | |
699 | return -EINVAL; | |
700 | } | |
701 | } | |
702 | ||
703 | message->spi = spi; | |
704 | message->status = -EINPROGRESS; | |
705 | return master->transfer(spi, message); | |
706 | } | |
707 | ||
568d0697 DB |
708 | /** |
709 | * spi_async - asynchronous SPI transfer | |
710 | * @spi: device with which data will be exchanged | |
711 | * @message: describes the data transfers, including completion callback | |
712 | * Context: any (irqs may be blocked, etc) | |
713 | * | |
714 | * This call may be used in_irq and other contexts which can't sleep, | |
715 | * as well as from task contexts which can sleep. | |
716 | * | |
717 | * The completion callback is invoked in a context which can't sleep. | |
718 | * Before that invocation, the value of message->status is undefined. | |
719 | * When the callback is issued, message->status holds either zero (to | |
720 | * indicate complete success) or a negative error code. After that | |
721 | * callback returns, the driver which issued the transfer request may | |
722 | * deallocate the associated memory; it's no longer in use by any SPI | |
723 | * core or controller driver code. | |
724 | * | |
725 | * Note that although all messages to a spi_device are handled in | |
726 | * FIFO order, messages may go to different devices in other orders. | |
727 | * Some device might be higher priority, or have various "hard" access | |
728 | * time requirements, for example. | |
729 | * | |
730 | * On detection of any fault during the transfer, processing of | |
731 | * the entire message is aborted, and the device is deselected. | |
732 | * Until returning from the associated message completion callback, | |
733 | * no other spi_message queued to that device will be processed. | |
734 | * (This rule applies equally to all the synchronous transfer calls, | |
735 | * which are wrappers around this core asynchronous primitive.) | |
736 | */ | |
737 | int spi_async(struct spi_device *spi, struct spi_message *message) | |
738 | { | |
739 | struct spi_master *master = spi->master; | |
cf32b71e ES |
740 | int ret; |
741 | unsigned long flags; | |
568d0697 | 742 | |
cf32b71e | 743 | spin_lock_irqsave(&master->bus_lock_spinlock, flags); |
568d0697 | 744 | |
cf32b71e ES |
745 | if (master->bus_lock_flag) |
746 | ret = -EBUSY; | |
747 | else | |
748 | ret = __spi_async(spi, message); | |
568d0697 | 749 | |
cf32b71e ES |
750 | spin_unlock_irqrestore(&master->bus_lock_spinlock, flags); |
751 | ||
752 | return ret; | |
568d0697 DB |
753 | } |
754 | EXPORT_SYMBOL_GPL(spi_async); | |
755 | ||
cf32b71e ES |
756 | /** |
757 | * spi_async_locked - version of spi_async with exclusive bus usage | |
758 | * @spi: device with which data will be exchanged | |
759 | * @message: describes the data transfers, including completion callback | |
760 | * Context: any (irqs may be blocked, etc) | |
761 | * | |
762 | * This call may be used in_irq and other contexts which can't sleep, | |
763 | * as well as from task contexts which can sleep. | |
764 | * | |
765 | * The completion callback is invoked in a context which can't sleep. | |
766 | * Before that invocation, the value of message->status is undefined. | |
767 | * When the callback is issued, message->status holds either zero (to | |
768 | * indicate complete success) or a negative error code. After that | |
769 | * callback returns, the driver which issued the transfer request may | |
770 | * deallocate the associated memory; it's no longer in use by any SPI | |
771 | * core or controller driver code. | |
772 | * | |
773 | * Note that although all messages to a spi_device are handled in | |
774 | * FIFO order, messages may go to different devices in other orders. | |
775 | * Some device might be higher priority, or have various "hard" access | |
776 | * time requirements, for example. | |
777 | * | |
778 | * On detection of any fault during the transfer, processing of | |
779 | * the entire message is aborted, and the device is deselected. | |
780 | * Until returning from the associated message completion callback, | |
781 | * no other spi_message queued to that device will be processed. | |
782 | * (This rule applies equally to all the synchronous transfer calls, | |
783 | * which are wrappers around this core asynchronous primitive.) | |
784 | */ | |
785 | int spi_async_locked(struct spi_device *spi, struct spi_message *message) | |
786 | { | |
787 | struct spi_master *master = spi->master; | |
788 | int ret; | |
789 | unsigned long flags; | |
790 | ||
791 | spin_lock_irqsave(&master->bus_lock_spinlock, flags); | |
792 | ||
793 | ret = __spi_async(spi, message); | |
794 | ||
795 | spin_unlock_irqrestore(&master->bus_lock_spinlock, flags); | |
796 | ||
797 | return ret; | |
798 | ||
799 | } | |
800 | EXPORT_SYMBOL_GPL(spi_async_locked); | |
801 | ||
7d077197 DB |
802 | |
803 | /*-------------------------------------------------------------------------*/ | |
804 | ||
805 | /* Utility methods for SPI master protocol drivers, layered on | |
806 | * top of the core. Some other utility methods are defined as | |
807 | * inline functions. | |
808 | */ | |
809 | ||
5d870c8e AM |
810 | static void spi_complete(void *arg) |
811 | { | |
812 | complete(arg); | |
813 | } | |
814 | ||
cf32b71e ES |
815 | static int __spi_sync(struct spi_device *spi, struct spi_message *message, |
816 | int bus_locked) | |
817 | { | |
818 | DECLARE_COMPLETION_ONSTACK(done); | |
819 | int status; | |
820 | struct spi_master *master = spi->master; | |
821 | ||
822 | message->complete = spi_complete; | |
823 | message->context = &done; | |
824 | ||
825 | if (!bus_locked) | |
826 | mutex_lock(&master->bus_lock_mutex); | |
827 | ||
828 | status = spi_async_locked(spi, message); | |
829 | ||
830 | if (!bus_locked) | |
831 | mutex_unlock(&master->bus_lock_mutex); | |
832 | ||
833 | if (status == 0) { | |
834 | wait_for_completion(&done); | |
835 | status = message->status; | |
836 | } | |
837 | message->context = NULL; | |
838 | return status; | |
839 | } | |
840 | ||
8ae12a0d DB |
841 | /** |
842 | * spi_sync - blocking/synchronous SPI data transfers | |
843 | * @spi: device with which data will be exchanged | |
844 | * @message: describes the data transfers | |
33e34dc6 | 845 | * Context: can sleep |
8ae12a0d DB |
846 | * |
847 | * This call may only be used from a context that may sleep. The sleep | |
848 | * is non-interruptible, and has no timeout. Low-overhead controller | |
849 | * drivers may DMA directly into and out of the message buffers. | |
850 | * | |
851 | * Note that the SPI device's chip select is active during the message, | |
852 | * and then is normally disabled between messages. Drivers for some | |
853 | * frequently-used devices may want to minimize costs of selecting a chip, | |
854 | * by leaving it selected in anticipation that the next message will go | |
855 | * to the same chip. (That may increase power usage.) | |
856 | * | |
0c868461 DB |
857 | * Also, the caller is guaranteeing that the memory associated with the |
858 | * message will not be freed before this call returns. | |
859 | * | |
9b938b74 | 860 | * It returns zero on success, else a negative error code. |
8ae12a0d DB |
861 | */ |
862 | int spi_sync(struct spi_device *spi, struct spi_message *message) | |
863 | { | |
cf32b71e | 864 | return __spi_sync(spi, message, 0); |
8ae12a0d DB |
865 | } |
866 | EXPORT_SYMBOL_GPL(spi_sync); | |
867 | ||
cf32b71e ES |
868 | /** |
869 | * spi_sync_locked - version of spi_sync with exclusive bus usage | |
870 | * @spi: device with which data will be exchanged | |
871 | * @message: describes the data transfers | |
872 | * Context: can sleep | |
873 | * | |
874 | * This call may only be used from a context that may sleep. The sleep | |
875 | * is non-interruptible, and has no timeout. Low-overhead controller | |
876 | * drivers may DMA directly into and out of the message buffers. | |
877 | * | |
878 | * This call should be used by drivers that require exclusive access to the | |
879 | * SPI bus. It has to be preceeded by a spi_bus_lock call. The SPI bus must | |
880 | * be released by a spi_bus_unlock call when the exclusive access is over. | |
881 | * | |
882 | * It returns zero on success, else a negative error code. | |
883 | */ | |
884 | int spi_sync_locked(struct spi_device *spi, struct spi_message *message) | |
885 | { | |
886 | return __spi_sync(spi, message, 1); | |
887 | } | |
888 | EXPORT_SYMBOL_GPL(spi_sync_locked); | |
889 | ||
890 | /** | |
891 | * spi_bus_lock - obtain a lock for exclusive SPI bus usage | |
892 | * @master: SPI bus master that should be locked for exclusive bus access | |
893 | * Context: can sleep | |
894 | * | |
895 | * This call may only be used from a context that may sleep. The sleep | |
896 | * is non-interruptible, and has no timeout. | |
897 | * | |
898 | * This call should be used by drivers that require exclusive access to the | |
899 | * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the | |
900 | * exclusive access is over. Data transfer must be done by spi_sync_locked | |
901 | * and spi_async_locked calls when the SPI bus lock is held. | |
902 | * | |
903 | * It returns zero on success, else a negative error code. | |
904 | */ | |
905 | int spi_bus_lock(struct spi_master *master) | |
906 | { | |
907 | unsigned long flags; | |
908 | ||
909 | mutex_lock(&master->bus_lock_mutex); | |
910 | ||
911 | spin_lock_irqsave(&master->bus_lock_spinlock, flags); | |
912 | master->bus_lock_flag = 1; | |
913 | spin_unlock_irqrestore(&master->bus_lock_spinlock, flags); | |
914 | ||
915 | /* mutex remains locked until spi_bus_unlock is called */ | |
916 | ||
917 | return 0; | |
918 | } | |
919 | EXPORT_SYMBOL_GPL(spi_bus_lock); | |
920 | ||
921 | /** | |
922 | * spi_bus_unlock - release the lock for exclusive SPI bus usage | |
923 | * @master: SPI bus master that was locked for exclusive bus access | |
924 | * Context: can sleep | |
925 | * | |
926 | * This call may only be used from a context that may sleep. The sleep | |
927 | * is non-interruptible, and has no timeout. | |
928 | * | |
929 | * This call releases an SPI bus lock previously obtained by an spi_bus_lock | |
930 | * call. | |
931 | * | |
932 | * It returns zero on success, else a negative error code. | |
933 | */ | |
934 | int spi_bus_unlock(struct spi_master *master) | |
935 | { | |
936 | master->bus_lock_flag = 0; | |
937 | ||
938 | mutex_unlock(&master->bus_lock_mutex); | |
939 | ||
940 | return 0; | |
941 | } | |
942 | EXPORT_SYMBOL_GPL(spi_bus_unlock); | |
943 | ||
a9948b61 DB |
944 | /* portable code must never pass more than 32 bytes */ |
945 | #define SPI_BUFSIZ max(32,SMP_CACHE_BYTES) | |
8ae12a0d DB |
946 | |
947 | static u8 *buf; | |
948 | ||
949 | /** | |
950 | * spi_write_then_read - SPI synchronous write followed by read | |
951 | * @spi: device with which data will be exchanged | |
952 | * @txbuf: data to be written (need not be dma-safe) | |
953 | * @n_tx: size of txbuf, in bytes | |
27570497 JP |
954 | * @rxbuf: buffer into which data will be read (need not be dma-safe) |
955 | * @n_rx: size of rxbuf, in bytes | |
33e34dc6 | 956 | * Context: can sleep |
8ae12a0d DB |
957 | * |
958 | * This performs a half duplex MicroWire style transaction with the | |
959 | * device, sending txbuf and then reading rxbuf. The return value | |
960 | * is zero for success, else a negative errno status code. | |
b885244e | 961 | * This call may only be used from a context that may sleep. |
8ae12a0d | 962 | * |
0c868461 | 963 | * Parameters to this routine are always copied using a small buffer; |
33e34dc6 DB |
964 | * portable code should never use this for more than 32 bytes. |
965 | * Performance-sensitive or bulk transfer code should instead use | |
0c868461 | 966 | * spi_{async,sync}() calls with dma-safe buffers. |
8ae12a0d DB |
967 | */ |
968 | int spi_write_then_read(struct spi_device *spi, | |
969 | const u8 *txbuf, unsigned n_tx, | |
970 | u8 *rxbuf, unsigned n_rx) | |
971 | { | |
068f4070 | 972 | static DEFINE_MUTEX(lock); |
8ae12a0d DB |
973 | |
974 | int status; | |
975 | struct spi_message message; | |
bdff549e | 976 | struct spi_transfer x[2]; |
8ae12a0d DB |
977 | u8 *local_buf; |
978 | ||
979 | /* Use preallocated DMA-safe buffer. We can't avoid copying here, | |
980 | * (as a pure convenience thing), but we can keep heap costs | |
981 | * out of the hot path ... | |
982 | */ | |
983 | if ((n_tx + n_rx) > SPI_BUFSIZ) | |
984 | return -EINVAL; | |
985 | ||
8275c642 | 986 | spi_message_init(&message); |
bdff549e DB |
987 | memset(x, 0, sizeof x); |
988 | if (n_tx) { | |
989 | x[0].len = n_tx; | |
990 | spi_message_add_tail(&x[0], &message); | |
991 | } | |
992 | if (n_rx) { | |
993 | x[1].len = n_rx; | |
994 | spi_message_add_tail(&x[1], &message); | |
995 | } | |
8275c642 | 996 | |
8ae12a0d | 997 | /* ... unless someone else is using the pre-allocated buffer */ |
068f4070 | 998 | if (!mutex_trylock(&lock)) { |
8ae12a0d DB |
999 | local_buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL); |
1000 | if (!local_buf) | |
1001 | return -ENOMEM; | |
1002 | } else | |
1003 | local_buf = buf; | |
1004 | ||
8ae12a0d | 1005 | memcpy(local_buf, txbuf, n_tx); |
bdff549e DB |
1006 | x[0].tx_buf = local_buf; |
1007 | x[1].rx_buf = local_buf + n_tx; | |
8ae12a0d DB |
1008 | |
1009 | /* do the i/o */ | |
8ae12a0d | 1010 | status = spi_sync(spi, &message); |
9b938b74 | 1011 | if (status == 0) |
bdff549e | 1012 | memcpy(rxbuf, x[1].rx_buf, n_rx); |
8ae12a0d | 1013 | |
bdff549e | 1014 | if (x[0].tx_buf == buf) |
068f4070 | 1015 | mutex_unlock(&lock); |
8ae12a0d DB |
1016 | else |
1017 | kfree(local_buf); | |
1018 | ||
1019 | return status; | |
1020 | } | |
1021 | EXPORT_SYMBOL_GPL(spi_write_then_read); | |
1022 | ||
1023 | /*-------------------------------------------------------------------------*/ | |
1024 | ||
1025 | static int __init spi_init(void) | |
1026 | { | |
b885244e DB |
1027 | int status; |
1028 | ||
e94b1766 | 1029 | buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL); |
b885244e DB |
1030 | if (!buf) { |
1031 | status = -ENOMEM; | |
1032 | goto err0; | |
1033 | } | |
1034 | ||
1035 | status = bus_register(&spi_bus_type); | |
1036 | if (status < 0) | |
1037 | goto err1; | |
8ae12a0d | 1038 | |
b885244e DB |
1039 | status = class_register(&spi_master_class); |
1040 | if (status < 0) | |
1041 | goto err2; | |
8ae12a0d | 1042 | return 0; |
b885244e DB |
1043 | |
1044 | err2: | |
1045 | bus_unregister(&spi_bus_type); | |
1046 | err1: | |
1047 | kfree(buf); | |
1048 | buf = NULL; | |
1049 | err0: | |
1050 | return status; | |
8ae12a0d | 1051 | } |
b885244e | 1052 | |
8ae12a0d DB |
1053 | /* board_info is normally registered in arch_initcall(), |
1054 | * but even essential drivers wait till later | |
b885244e DB |
1055 | * |
1056 | * REVISIT only boardinfo really needs static linking. the rest (device and | |
1057 | * driver registration) _could_ be dynamically linked (modular) ... costs | |
1058 | * include needing to have boardinfo data structures be much more public. | |
8ae12a0d | 1059 | */ |
673c0c00 | 1060 | postcore_initcall(spi_init); |
8ae12a0d | 1061 |