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