Commit | Line | Data |
---|---|---|
8ae12a0d | 1 | /* |
ca632f55 | 2 | * SPI init/core code |
8ae12a0d DB |
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> |
3ae22e8c | 31 | #include <linux/pm_runtime.h> |
025ed130 | 32 | #include <linux/export.h> |
ffbbdd21 LW |
33 | #include <linux/sched.h> |
34 | #include <linux/delay.h> | |
35 | #include <linux/kthread.h> | |
8ae12a0d | 36 | |
8ae12a0d DB |
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 | ||
3ae22e8c MB |
108 | #ifdef CONFIG_PM_SLEEP |
109 | static int spi_legacy_suspend(struct device *dev, pm_message_t message) | |
8ae12a0d | 110 | { |
3c72426f | 111 | int value = 0; |
b885244e | 112 | struct spi_driver *drv = to_spi_driver(dev->driver); |
8ae12a0d | 113 | |
8ae12a0d | 114 | /* suspend will stop irqs and dma; no more i/o */ |
3c72426f DB |
115 | if (drv) { |
116 | if (drv->suspend) | |
117 | value = drv->suspend(to_spi_device(dev), message); | |
118 | else | |
119 | dev_dbg(dev, "... can't suspend\n"); | |
120 | } | |
8ae12a0d DB |
121 | return value; |
122 | } | |
123 | ||
3ae22e8c | 124 | static int spi_legacy_resume(struct device *dev) |
8ae12a0d | 125 | { |
3c72426f | 126 | int value = 0; |
b885244e | 127 | struct spi_driver *drv = to_spi_driver(dev->driver); |
8ae12a0d | 128 | |
8ae12a0d | 129 | /* resume may restart the i/o queue */ |
3c72426f DB |
130 | if (drv) { |
131 | if (drv->resume) | |
132 | value = drv->resume(to_spi_device(dev)); | |
133 | else | |
134 | dev_dbg(dev, "... can't resume\n"); | |
135 | } | |
8ae12a0d DB |
136 | return value; |
137 | } | |
138 | ||
3ae22e8c MB |
139 | static int spi_pm_suspend(struct device *dev) |
140 | { | |
141 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
142 | ||
143 | if (pm) | |
144 | return pm_generic_suspend(dev); | |
145 | else | |
146 | return spi_legacy_suspend(dev, PMSG_SUSPEND); | |
147 | } | |
148 | ||
149 | static int spi_pm_resume(struct device *dev) | |
150 | { | |
151 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
152 | ||
153 | if (pm) | |
154 | return pm_generic_resume(dev); | |
155 | else | |
156 | return spi_legacy_resume(dev); | |
157 | } | |
158 | ||
159 | static int spi_pm_freeze(struct device *dev) | |
160 | { | |
161 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
162 | ||
163 | if (pm) | |
164 | return pm_generic_freeze(dev); | |
165 | else | |
166 | return spi_legacy_suspend(dev, PMSG_FREEZE); | |
167 | } | |
168 | ||
169 | static int spi_pm_thaw(struct device *dev) | |
170 | { | |
171 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
172 | ||
173 | if (pm) | |
174 | return pm_generic_thaw(dev); | |
175 | else | |
176 | return spi_legacy_resume(dev); | |
177 | } | |
178 | ||
179 | static int spi_pm_poweroff(struct device *dev) | |
180 | { | |
181 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
182 | ||
183 | if (pm) | |
184 | return pm_generic_poweroff(dev); | |
185 | else | |
186 | return spi_legacy_suspend(dev, PMSG_HIBERNATE); | |
187 | } | |
188 | ||
189 | static int spi_pm_restore(struct device *dev) | |
190 | { | |
191 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
192 | ||
193 | if (pm) | |
194 | return pm_generic_restore(dev); | |
195 | else | |
196 | return spi_legacy_resume(dev); | |
197 | } | |
8ae12a0d | 198 | #else |
3ae22e8c MB |
199 | #define spi_pm_suspend NULL |
200 | #define spi_pm_resume NULL | |
201 | #define spi_pm_freeze NULL | |
202 | #define spi_pm_thaw NULL | |
203 | #define spi_pm_poweroff NULL | |
204 | #define spi_pm_restore NULL | |
8ae12a0d DB |
205 | #endif |
206 | ||
3ae22e8c MB |
207 | static const struct dev_pm_ops spi_pm = { |
208 | .suspend = spi_pm_suspend, | |
209 | .resume = spi_pm_resume, | |
210 | .freeze = spi_pm_freeze, | |
211 | .thaw = spi_pm_thaw, | |
212 | .poweroff = spi_pm_poweroff, | |
213 | .restore = spi_pm_restore, | |
214 | SET_RUNTIME_PM_OPS( | |
215 | pm_generic_runtime_suspend, | |
216 | pm_generic_runtime_resume, | |
217 | pm_generic_runtime_idle | |
218 | ) | |
219 | }; | |
220 | ||
8ae12a0d DB |
221 | struct bus_type spi_bus_type = { |
222 | .name = "spi", | |
223 | .dev_attrs = spi_dev_attrs, | |
224 | .match = spi_match_device, | |
225 | .uevent = spi_uevent, | |
3ae22e8c | 226 | .pm = &spi_pm, |
8ae12a0d DB |
227 | }; |
228 | EXPORT_SYMBOL_GPL(spi_bus_type); | |
229 | ||
b885244e DB |
230 | |
231 | static int spi_drv_probe(struct device *dev) | |
232 | { | |
233 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); | |
234 | ||
235 | return sdrv->probe(to_spi_device(dev)); | |
236 | } | |
237 | ||
238 | static int spi_drv_remove(struct device *dev) | |
239 | { | |
240 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); | |
241 | ||
242 | return sdrv->remove(to_spi_device(dev)); | |
243 | } | |
244 | ||
245 | static void spi_drv_shutdown(struct device *dev) | |
246 | { | |
247 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); | |
248 | ||
249 | sdrv->shutdown(to_spi_device(dev)); | |
250 | } | |
251 | ||
33e34dc6 DB |
252 | /** |
253 | * spi_register_driver - register a SPI driver | |
254 | * @sdrv: the driver to register | |
255 | * Context: can sleep | |
256 | */ | |
b885244e DB |
257 | int spi_register_driver(struct spi_driver *sdrv) |
258 | { | |
259 | sdrv->driver.bus = &spi_bus_type; | |
260 | if (sdrv->probe) | |
261 | sdrv->driver.probe = spi_drv_probe; | |
262 | if (sdrv->remove) | |
263 | sdrv->driver.remove = spi_drv_remove; | |
264 | if (sdrv->shutdown) | |
265 | sdrv->driver.shutdown = spi_drv_shutdown; | |
266 | return driver_register(&sdrv->driver); | |
267 | } | |
268 | EXPORT_SYMBOL_GPL(spi_register_driver); | |
269 | ||
8ae12a0d DB |
270 | /*-------------------------------------------------------------------------*/ |
271 | ||
272 | /* SPI devices should normally not be created by SPI device drivers; that | |
273 | * would make them board-specific. Similarly with SPI master drivers. | |
274 | * Device registration normally goes into like arch/.../mach.../board-YYY.c | |
275 | * with other readonly (flashable) information about mainboard devices. | |
276 | */ | |
277 | ||
278 | struct boardinfo { | |
279 | struct list_head list; | |
2b9603a0 | 280 | struct spi_board_info board_info; |
8ae12a0d DB |
281 | }; |
282 | ||
283 | static LIST_HEAD(board_list); | |
2b9603a0 FT |
284 | static LIST_HEAD(spi_master_list); |
285 | ||
286 | /* | |
287 | * Used to protect add/del opertion for board_info list and | |
288 | * spi_master list, and their matching process | |
289 | */ | |
94040828 | 290 | static DEFINE_MUTEX(board_lock); |
8ae12a0d | 291 | |
dc87c98e GL |
292 | /** |
293 | * spi_alloc_device - Allocate a new SPI device | |
294 | * @master: Controller to which device is connected | |
295 | * Context: can sleep | |
296 | * | |
297 | * Allows a driver to allocate and initialize a spi_device without | |
298 | * registering it immediately. This allows a driver to directly | |
299 | * fill the spi_device with device parameters before calling | |
300 | * spi_add_device() on it. | |
301 | * | |
302 | * Caller is responsible to call spi_add_device() on the returned | |
303 | * spi_device structure to add it to the SPI master. If the caller | |
304 | * needs to discard the spi_device without adding it, then it should | |
305 | * call spi_dev_put() on it. | |
306 | * | |
307 | * Returns a pointer to the new device, or NULL. | |
308 | */ | |
309 | struct spi_device *spi_alloc_device(struct spi_master *master) | |
310 | { | |
311 | struct spi_device *spi; | |
312 | struct device *dev = master->dev.parent; | |
313 | ||
314 | if (!spi_master_get(master)) | |
315 | return NULL; | |
316 | ||
317 | spi = kzalloc(sizeof *spi, GFP_KERNEL); | |
318 | if (!spi) { | |
319 | dev_err(dev, "cannot alloc spi_device\n"); | |
320 | spi_master_put(master); | |
321 | return NULL; | |
322 | } | |
323 | ||
324 | spi->master = master; | |
178db7d3 | 325 | spi->dev.parent = &master->dev; |
dc87c98e GL |
326 | spi->dev.bus = &spi_bus_type; |
327 | spi->dev.release = spidev_release; | |
328 | device_initialize(&spi->dev); | |
329 | return spi; | |
330 | } | |
331 | EXPORT_SYMBOL_GPL(spi_alloc_device); | |
332 | ||
333 | /** | |
334 | * spi_add_device - Add spi_device allocated with spi_alloc_device | |
335 | * @spi: spi_device to register | |
336 | * | |
337 | * Companion function to spi_alloc_device. Devices allocated with | |
338 | * spi_alloc_device can be added onto the spi bus with this function. | |
339 | * | |
e48880e0 | 340 | * Returns 0 on success; negative errno on failure |
dc87c98e GL |
341 | */ |
342 | int spi_add_device(struct spi_device *spi) | |
343 | { | |
e48880e0 | 344 | static DEFINE_MUTEX(spi_add_lock); |
dc87c98e | 345 | struct device *dev = spi->master->dev.parent; |
8ec130a0 | 346 | struct device *d; |
dc87c98e GL |
347 | int status; |
348 | ||
349 | /* Chipselects are numbered 0..max; validate. */ | |
350 | if (spi->chip_select >= spi->master->num_chipselect) { | |
351 | dev_err(dev, "cs%d >= max %d\n", | |
352 | spi->chip_select, | |
353 | spi->master->num_chipselect); | |
354 | return -EINVAL; | |
355 | } | |
356 | ||
357 | /* Set the bus ID string */ | |
35f74fca | 358 | dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev), |
dc87c98e GL |
359 | spi->chip_select); |
360 | ||
e48880e0 DB |
361 | |
362 | /* We need to make sure there's no other device with this | |
363 | * chipselect **BEFORE** we call setup(), else we'll trash | |
364 | * its configuration. Lock against concurrent add() calls. | |
365 | */ | |
366 | mutex_lock(&spi_add_lock); | |
367 | ||
8ec130a0 RT |
368 | d = bus_find_device_by_name(&spi_bus_type, NULL, dev_name(&spi->dev)); |
369 | if (d != NULL) { | |
e48880e0 DB |
370 | dev_err(dev, "chipselect %d already in use\n", |
371 | spi->chip_select); | |
8ec130a0 | 372 | put_device(d); |
e48880e0 DB |
373 | status = -EBUSY; |
374 | goto done; | |
375 | } | |
376 | ||
377 | /* Drivers may modify this initial i/o setup, but will | |
378 | * normally rely on the device being setup. Devices | |
379 | * using SPI_CS_HIGH can't coexist well otherwise... | |
380 | */ | |
7d077197 | 381 | status = spi_setup(spi); |
dc87c98e | 382 | if (status < 0) { |
eb288a1f LW |
383 | dev_err(dev, "can't setup %s, status %d\n", |
384 | dev_name(&spi->dev), status); | |
e48880e0 | 385 | goto done; |
dc87c98e GL |
386 | } |
387 | ||
e48880e0 | 388 | /* Device may be bound to an active driver when this returns */ |
dc87c98e | 389 | status = device_add(&spi->dev); |
e48880e0 | 390 | if (status < 0) |
eb288a1f LW |
391 | dev_err(dev, "can't add %s, status %d\n", |
392 | dev_name(&spi->dev), status); | |
e48880e0 | 393 | else |
35f74fca | 394 | dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev)); |
dc87c98e | 395 | |
e48880e0 DB |
396 | done: |
397 | mutex_unlock(&spi_add_lock); | |
398 | return status; | |
dc87c98e GL |
399 | } |
400 | EXPORT_SYMBOL_GPL(spi_add_device); | |
8ae12a0d | 401 | |
33e34dc6 DB |
402 | /** |
403 | * spi_new_device - instantiate one new SPI device | |
404 | * @master: Controller to which device is connected | |
405 | * @chip: Describes the SPI device | |
406 | * Context: can sleep | |
407 | * | |
408 | * On typical mainboards, this is purely internal; and it's not needed | |
8ae12a0d DB |
409 | * after board init creates the hard-wired devices. Some development |
410 | * platforms may not be able to use spi_register_board_info though, and | |
411 | * this is exported so that for example a USB or parport based adapter | |
412 | * driver could add devices (which it would learn about out-of-band). | |
082c8cb4 DB |
413 | * |
414 | * Returns the new device, or NULL. | |
8ae12a0d | 415 | */ |
e9d5a461 AB |
416 | struct spi_device *spi_new_device(struct spi_master *master, |
417 | struct spi_board_info *chip) | |
8ae12a0d DB |
418 | { |
419 | struct spi_device *proxy; | |
8ae12a0d DB |
420 | int status; |
421 | ||
082c8cb4 DB |
422 | /* NOTE: caller did any chip->bus_num checks necessary. |
423 | * | |
424 | * Also, unless we change the return value convention to use | |
425 | * error-or-pointer (not NULL-or-pointer), troubleshootability | |
426 | * suggests syslogged diagnostics are best here (ugh). | |
427 | */ | |
428 | ||
dc87c98e GL |
429 | proxy = spi_alloc_device(master); |
430 | if (!proxy) | |
8ae12a0d DB |
431 | return NULL; |
432 | ||
102eb975 GL |
433 | WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias)); |
434 | ||
8ae12a0d DB |
435 | proxy->chip_select = chip->chip_select; |
436 | proxy->max_speed_hz = chip->max_speed_hz; | |
980a01c9 | 437 | proxy->mode = chip->mode; |
8ae12a0d | 438 | proxy->irq = chip->irq; |
102eb975 | 439 | strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias)); |
8ae12a0d DB |
440 | proxy->dev.platform_data = (void *) chip->platform_data; |
441 | proxy->controller_data = chip->controller_data; | |
442 | proxy->controller_state = NULL; | |
8ae12a0d | 443 | |
dc87c98e | 444 | status = spi_add_device(proxy); |
8ae12a0d | 445 | if (status < 0) { |
dc87c98e GL |
446 | spi_dev_put(proxy); |
447 | return NULL; | |
8ae12a0d DB |
448 | } |
449 | ||
8ae12a0d DB |
450 | return proxy; |
451 | } | |
452 | EXPORT_SYMBOL_GPL(spi_new_device); | |
453 | ||
2b9603a0 FT |
454 | static void spi_match_master_to_boardinfo(struct spi_master *master, |
455 | struct spi_board_info *bi) | |
456 | { | |
457 | struct spi_device *dev; | |
458 | ||
459 | if (master->bus_num != bi->bus_num) | |
460 | return; | |
461 | ||
462 | dev = spi_new_device(master, bi); | |
463 | if (!dev) | |
464 | dev_err(master->dev.parent, "can't create new device for %s\n", | |
465 | bi->modalias); | |
466 | } | |
467 | ||
33e34dc6 DB |
468 | /** |
469 | * spi_register_board_info - register SPI devices for a given board | |
470 | * @info: array of chip descriptors | |
471 | * @n: how many descriptors are provided | |
472 | * Context: can sleep | |
473 | * | |
8ae12a0d DB |
474 | * Board-specific early init code calls this (probably during arch_initcall) |
475 | * with segments of the SPI device table. Any device nodes are created later, | |
476 | * after the relevant parent SPI controller (bus_num) is defined. We keep | |
477 | * this table of devices forever, so that reloading a controller driver will | |
478 | * not make Linux forget about these hard-wired devices. | |
479 | * | |
480 | * Other code can also call this, e.g. a particular add-on board might provide | |
481 | * SPI devices through its expansion connector, so code initializing that board | |
482 | * would naturally declare its SPI devices. | |
483 | * | |
484 | * The board info passed can safely be __initdata ... but be careful of | |
485 | * any embedded pointers (platform_data, etc), they're copied as-is. | |
486 | */ | |
690fb11b | 487 | int __devinit |
8ae12a0d DB |
488 | spi_register_board_info(struct spi_board_info const *info, unsigned n) |
489 | { | |
2b9603a0 FT |
490 | struct boardinfo *bi; |
491 | int i; | |
8ae12a0d | 492 | |
2b9603a0 | 493 | bi = kzalloc(n * sizeof(*bi), GFP_KERNEL); |
8ae12a0d DB |
494 | if (!bi) |
495 | return -ENOMEM; | |
8ae12a0d | 496 | |
2b9603a0 FT |
497 | for (i = 0; i < n; i++, bi++, info++) { |
498 | struct spi_master *master; | |
8ae12a0d | 499 | |
2b9603a0 FT |
500 | memcpy(&bi->board_info, info, sizeof(*info)); |
501 | mutex_lock(&board_lock); | |
502 | list_add_tail(&bi->list, &board_list); | |
503 | list_for_each_entry(master, &spi_master_list, list) | |
504 | spi_match_master_to_boardinfo(master, &bi->board_info); | |
505 | mutex_unlock(&board_lock); | |
8ae12a0d | 506 | } |
2b9603a0 FT |
507 | |
508 | return 0; | |
8ae12a0d DB |
509 | } |
510 | ||
511 | /*-------------------------------------------------------------------------*/ | |
512 | ||
ffbbdd21 LW |
513 | /** |
514 | * spi_pump_messages - kthread work function which processes spi message queue | |
515 | * @work: pointer to kthread work struct contained in the master struct | |
516 | * | |
517 | * This function checks if there is any spi message in the queue that | |
518 | * needs processing and if so call out to the driver to initialize hardware | |
519 | * and transfer each message. | |
520 | * | |
521 | */ | |
522 | static void spi_pump_messages(struct kthread_work *work) | |
523 | { | |
524 | struct spi_master *master = | |
525 | container_of(work, struct spi_master, pump_messages); | |
526 | unsigned long flags; | |
527 | bool was_busy = false; | |
528 | int ret; | |
529 | ||
530 | /* Lock queue and check for queue work */ | |
531 | spin_lock_irqsave(&master->queue_lock, flags); | |
532 | if (list_empty(&master->queue) || !master->running) { | |
533 | if (master->busy) { | |
534 | ret = master->unprepare_transfer_hardware(master); | |
535 | if (ret) { | |
536 | dev_err(&master->dev, | |
537 | "failed to unprepare transfer hardware\n"); | |
538 | return; | |
539 | } | |
540 | } | |
541 | master->busy = false; | |
542 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
543 | return; | |
544 | } | |
545 | ||
546 | /* Make sure we are not already running a message */ | |
547 | if (master->cur_msg) { | |
548 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
549 | return; | |
550 | } | |
551 | /* Extract head of queue */ | |
552 | master->cur_msg = | |
553 | list_entry(master->queue.next, struct spi_message, queue); | |
554 | ||
555 | list_del_init(&master->cur_msg->queue); | |
556 | if (master->busy) | |
557 | was_busy = true; | |
558 | else | |
559 | master->busy = true; | |
560 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
561 | ||
562 | if (!was_busy) { | |
563 | ret = master->prepare_transfer_hardware(master); | |
564 | if (ret) { | |
565 | dev_err(&master->dev, | |
566 | "failed to prepare transfer hardware\n"); | |
567 | return; | |
568 | } | |
569 | } | |
570 | ||
571 | ret = master->transfer_one_message(master, master->cur_msg); | |
572 | if (ret) { | |
573 | dev_err(&master->dev, | |
574 | "failed to transfer one message from queue\n"); | |
575 | return; | |
576 | } | |
577 | } | |
578 | ||
579 | static int spi_init_queue(struct spi_master *master) | |
580 | { | |
581 | struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 }; | |
582 | ||
583 | INIT_LIST_HEAD(&master->queue); | |
584 | spin_lock_init(&master->queue_lock); | |
585 | ||
586 | master->running = false; | |
587 | master->busy = false; | |
588 | ||
589 | init_kthread_worker(&master->kworker); | |
590 | master->kworker_task = kthread_run(kthread_worker_fn, | |
591 | &master->kworker, | |
592 | dev_name(&master->dev)); | |
593 | if (IS_ERR(master->kworker_task)) { | |
594 | dev_err(&master->dev, "failed to create message pump task\n"); | |
595 | return -ENOMEM; | |
596 | } | |
597 | init_kthread_work(&master->pump_messages, spi_pump_messages); | |
598 | ||
599 | /* | |
600 | * Master config will indicate if this controller should run the | |
601 | * message pump with high (realtime) priority to reduce the transfer | |
602 | * latency on the bus by minimising the delay between a transfer | |
603 | * request and the scheduling of the message pump thread. Without this | |
604 | * setting the message pump thread will remain at default priority. | |
605 | */ | |
606 | if (master->rt) { | |
607 | dev_info(&master->dev, | |
608 | "will run message pump with realtime priority\n"); | |
609 | sched_setscheduler(master->kworker_task, SCHED_FIFO, ¶m); | |
610 | } | |
611 | ||
612 | return 0; | |
613 | } | |
614 | ||
615 | /** | |
616 | * spi_get_next_queued_message() - called by driver to check for queued | |
617 | * messages | |
618 | * @master: the master to check for queued messages | |
619 | * | |
620 | * If there are more messages in the queue, the next message is returned from | |
621 | * this call. | |
622 | */ | |
623 | struct spi_message *spi_get_next_queued_message(struct spi_master *master) | |
624 | { | |
625 | struct spi_message *next; | |
626 | unsigned long flags; | |
627 | ||
628 | /* get a pointer to the next message, if any */ | |
629 | spin_lock_irqsave(&master->queue_lock, flags); | |
630 | if (list_empty(&master->queue)) | |
631 | next = NULL; | |
632 | else | |
633 | next = list_entry(master->queue.next, | |
634 | struct spi_message, queue); | |
635 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
636 | ||
637 | return next; | |
638 | } | |
639 | EXPORT_SYMBOL_GPL(spi_get_next_queued_message); | |
640 | ||
641 | /** | |
642 | * spi_finalize_current_message() - the current message is complete | |
643 | * @master: the master to return the message to | |
644 | * | |
645 | * Called by the driver to notify the core that the message in the front of the | |
646 | * queue is complete and can be removed from the queue. | |
647 | */ | |
648 | void spi_finalize_current_message(struct spi_master *master) | |
649 | { | |
650 | struct spi_message *mesg; | |
651 | unsigned long flags; | |
652 | ||
653 | spin_lock_irqsave(&master->queue_lock, flags); | |
654 | mesg = master->cur_msg; | |
655 | master->cur_msg = NULL; | |
656 | ||
657 | queue_kthread_work(&master->kworker, &master->pump_messages); | |
658 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
659 | ||
660 | mesg->state = NULL; | |
661 | if (mesg->complete) | |
662 | mesg->complete(mesg->context); | |
663 | } | |
664 | EXPORT_SYMBOL_GPL(spi_finalize_current_message); | |
665 | ||
666 | static int spi_start_queue(struct spi_master *master) | |
667 | { | |
668 | unsigned long flags; | |
669 | ||
670 | spin_lock_irqsave(&master->queue_lock, flags); | |
671 | ||
672 | if (master->running || master->busy) { | |
673 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
674 | return -EBUSY; | |
675 | } | |
676 | ||
677 | master->running = true; | |
678 | master->cur_msg = NULL; | |
679 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
680 | ||
681 | queue_kthread_work(&master->kworker, &master->pump_messages); | |
682 | ||
683 | return 0; | |
684 | } | |
685 | ||
686 | static int spi_stop_queue(struct spi_master *master) | |
687 | { | |
688 | unsigned long flags; | |
689 | unsigned limit = 500; | |
690 | int ret = 0; | |
691 | ||
692 | spin_lock_irqsave(&master->queue_lock, flags); | |
693 | ||
694 | /* | |
695 | * This is a bit lame, but is optimized for the common execution path. | |
696 | * A wait_queue on the master->busy could be used, but then the common | |
697 | * execution path (pump_messages) would be required to call wake_up or | |
698 | * friends on every SPI message. Do this instead. | |
699 | */ | |
700 | while ((!list_empty(&master->queue) || master->busy) && limit--) { | |
701 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
702 | msleep(10); | |
703 | spin_lock_irqsave(&master->queue_lock, flags); | |
704 | } | |
705 | ||
706 | if (!list_empty(&master->queue) || master->busy) | |
707 | ret = -EBUSY; | |
708 | else | |
709 | master->running = false; | |
710 | ||
711 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
712 | ||
713 | if (ret) { | |
714 | dev_warn(&master->dev, | |
715 | "could not stop message queue\n"); | |
716 | return ret; | |
717 | } | |
718 | return ret; | |
719 | } | |
720 | ||
721 | static int spi_destroy_queue(struct spi_master *master) | |
722 | { | |
723 | int ret; | |
724 | ||
725 | ret = spi_stop_queue(master); | |
726 | ||
727 | /* | |
728 | * flush_kthread_worker will block until all work is done. | |
729 | * If the reason that stop_queue timed out is that the work will never | |
730 | * finish, then it does no good to call flush/stop thread, so | |
731 | * return anyway. | |
732 | */ | |
733 | if (ret) { | |
734 | dev_err(&master->dev, "problem destroying queue\n"); | |
735 | return ret; | |
736 | } | |
737 | ||
738 | flush_kthread_worker(&master->kworker); | |
739 | kthread_stop(master->kworker_task); | |
740 | ||
741 | return 0; | |
742 | } | |
743 | ||
744 | /** | |
745 | * spi_queued_transfer - transfer function for queued transfers | |
746 | * @spi: spi device which is requesting transfer | |
747 | * @msg: spi message which is to handled is queued to driver queue | |
748 | */ | |
749 | static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg) | |
750 | { | |
751 | struct spi_master *master = spi->master; | |
752 | unsigned long flags; | |
753 | ||
754 | spin_lock_irqsave(&master->queue_lock, flags); | |
755 | ||
756 | if (!master->running) { | |
757 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
758 | return -ESHUTDOWN; | |
759 | } | |
760 | msg->actual_length = 0; | |
761 | msg->status = -EINPROGRESS; | |
762 | ||
763 | list_add_tail(&msg->queue, &master->queue); | |
764 | if (master->running && !master->busy) | |
765 | queue_kthread_work(&master->kworker, &master->pump_messages); | |
766 | ||
767 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
768 | return 0; | |
769 | } | |
770 | ||
771 | static int spi_master_initialize_queue(struct spi_master *master) | |
772 | { | |
773 | int ret; | |
774 | ||
775 | master->queued = true; | |
776 | master->transfer = spi_queued_transfer; | |
777 | ||
778 | /* Initialize and start queue */ | |
779 | ret = spi_init_queue(master); | |
780 | if (ret) { | |
781 | dev_err(&master->dev, "problem initializing queue\n"); | |
782 | goto err_init_queue; | |
783 | } | |
784 | ret = spi_start_queue(master); | |
785 | if (ret) { | |
786 | dev_err(&master->dev, "problem starting queue\n"); | |
787 | goto err_start_queue; | |
788 | } | |
789 | ||
790 | return 0; | |
791 | ||
792 | err_start_queue: | |
793 | err_init_queue: | |
794 | spi_destroy_queue(master); | |
795 | return ret; | |
796 | } | |
797 | ||
798 | /*-------------------------------------------------------------------------*/ | |
799 | ||
49dce689 | 800 | static void spi_master_release(struct device *dev) |
8ae12a0d DB |
801 | { |
802 | struct spi_master *master; | |
803 | ||
49dce689 | 804 | master = container_of(dev, struct spi_master, dev); |
8ae12a0d DB |
805 | kfree(master); |
806 | } | |
807 | ||
808 | static struct class spi_master_class = { | |
809 | .name = "spi_master", | |
810 | .owner = THIS_MODULE, | |
49dce689 | 811 | .dev_release = spi_master_release, |
8ae12a0d DB |
812 | }; |
813 | ||
814 | ||
ffbbdd21 | 815 | |
8ae12a0d DB |
816 | /** |
817 | * spi_alloc_master - allocate SPI master controller | |
818 | * @dev: the controller, possibly using the platform_bus | |
33e34dc6 | 819 | * @size: how much zeroed driver-private data to allocate; the pointer to this |
49dce689 | 820 | * memory is in the driver_data field of the returned device, |
0c868461 | 821 | * accessible with spi_master_get_devdata(). |
33e34dc6 | 822 | * Context: can sleep |
8ae12a0d DB |
823 | * |
824 | * This call is used only by SPI master controller drivers, which are the | |
825 | * only ones directly touching chip registers. It's how they allocate | |
ba1a0513 | 826 | * an spi_master structure, prior to calling spi_register_master(). |
8ae12a0d DB |
827 | * |
828 | * This must be called from context that can sleep. It returns the SPI | |
829 | * master structure on success, else NULL. | |
830 | * | |
831 | * The caller is responsible for assigning the bus number and initializing | |
ba1a0513 | 832 | * the master's methods before calling spi_register_master(); and (after errors |
eb4af0f5 UKK |
833 | * adding the device) calling spi_master_put() and kfree() to prevent a memory |
834 | * leak. | |
8ae12a0d | 835 | */ |
e9d5a461 | 836 | struct spi_master *spi_alloc_master(struct device *dev, unsigned size) |
8ae12a0d DB |
837 | { |
838 | struct spi_master *master; | |
839 | ||
0c868461 DB |
840 | if (!dev) |
841 | return NULL; | |
842 | ||
e94b1766 | 843 | master = kzalloc(size + sizeof *master, GFP_KERNEL); |
8ae12a0d DB |
844 | if (!master) |
845 | return NULL; | |
846 | ||
49dce689 TJ |
847 | device_initialize(&master->dev); |
848 | master->dev.class = &spi_master_class; | |
849 | master->dev.parent = get_device(dev); | |
0c868461 | 850 | spi_master_set_devdata(master, &master[1]); |
8ae12a0d DB |
851 | |
852 | return master; | |
853 | } | |
854 | EXPORT_SYMBOL_GPL(spi_alloc_master); | |
855 | ||
856 | /** | |
857 | * spi_register_master - register SPI master controller | |
858 | * @master: initialized master, originally from spi_alloc_master() | |
33e34dc6 | 859 | * Context: can sleep |
8ae12a0d DB |
860 | * |
861 | * SPI master controllers connect to their drivers using some non-SPI bus, | |
862 | * such as the platform bus. The final stage of probe() in that code | |
863 | * includes calling spi_register_master() to hook up to this SPI bus glue. | |
864 | * | |
865 | * SPI controllers use board specific (often SOC specific) bus numbers, | |
866 | * and board-specific addressing for SPI devices combines those numbers | |
867 | * with chip select numbers. Since SPI does not directly support dynamic | |
868 | * device identification, boards need configuration tables telling which | |
869 | * chip is at which address. | |
870 | * | |
871 | * This must be called from context that can sleep. It returns zero on | |
872 | * success, else a negative error code (dropping the master's refcount). | |
0c868461 DB |
873 | * After a successful return, the caller is responsible for calling |
874 | * spi_unregister_master(). | |
8ae12a0d | 875 | */ |
e9d5a461 | 876 | int spi_register_master(struct spi_master *master) |
8ae12a0d | 877 | { |
e44a45ae | 878 | static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1); |
49dce689 | 879 | struct device *dev = master->dev.parent; |
2b9603a0 | 880 | struct boardinfo *bi; |
8ae12a0d DB |
881 | int status = -ENODEV; |
882 | int dynamic = 0; | |
883 | ||
0c868461 DB |
884 | if (!dev) |
885 | return -ENODEV; | |
886 | ||
082c8cb4 DB |
887 | /* even if it's just one always-selected device, there must |
888 | * be at least one chipselect | |
889 | */ | |
890 | if (master->num_chipselect == 0) | |
891 | return -EINVAL; | |
892 | ||
8ae12a0d | 893 | /* convention: dynamically assigned bus IDs count down from the max */ |
a020ed75 | 894 | if (master->bus_num < 0) { |
082c8cb4 DB |
895 | /* FIXME switch to an IDR based scheme, something like |
896 | * I2C now uses, so we can't run out of "dynamic" IDs | |
897 | */ | |
8ae12a0d | 898 | master->bus_num = atomic_dec_return(&dyn_bus_id); |
b885244e | 899 | dynamic = 1; |
8ae12a0d DB |
900 | } |
901 | ||
cf32b71e ES |
902 | spin_lock_init(&master->bus_lock_spinlock); |
903 | mutex_init(&master->bus_lock_mutex); | |
904 | master->bus_lock_flag = 0; | |
905 | ||
8ae12a0d DB |
906 | /* register the device, then userspace will see it. |
907 | * registration fails if the bus ID is in use. | |
908 | */ | |
35f74fca | 909 | dev_set_name(&master->dev, "spi%u", master->bus_num); |
49dce689 | 910 | status = device_add(&master->dev); |
b885244e | 911 | if (status < 0) |
8ae12a0d | 912 | goto done; |
35f74fca | 913 | dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev), |
8ae12a0d DB |
914 | dynamic ? " (dynamic)" : ""); |
915 | ||
ffbbdd21 LW |
916 | /* If we're using a queued driver, start the queue */ |
917 | if (master->transfer) | |
918 | dev_info(dev, "master is unqueued, this is deprecated\n"); | |
919 | else { | |
920 | status = spi_master_initialize_queue(master); | |
921 | if (status) { | |
922 | device_unregister(&master->dev); | |
923 | goto done; | |
924 | } | |
925 | } | |
926 | ||
2b9603a0 FT |
927 | mutex_lock(&board_lock); |
928 | list_add_tail(&master->list, &spi_master_list); | |
929 | list_for_each_entry(bi, &board_list, list) | |
930 | spi_match_master_to_boardinfo(master, &bi->board_info); | |
931 | mutex_unlock(&board_lock); | |
932 | ||
8ae12a0d | 933 | status = 0; |
12b15e83 AG |
934 | |
935 | /* Register devices from the device tree */ | |
936 | of_register_spi_devices(master); | |
8ae12a0d DB |
937 | done: |
938 | return status; | |
939 | } | |
940 | EXPORT_SYMBOL_GPL(spi_register_master); | |
941 | ||
34860089 | 942 | static int __unregister(struct device *dev, void *null) |
8ae12a0d | 943 | { |
34860089 | 944 | spi_unregister_device(to_spi_device(dev)); |
8ae12a0d DB |
945 | return 0; |
946 | } | |
947 | ||
948 | /** | |
949 | * spi_unregister_master - unregister SPI master controller | |
950 | * @master: the master being unregistered | |
33e34dc6 | 951 | * Context: can sleep |
8ae12a0d DB |
952 | * |
953 | * This call is used only by SPI master controller drivers, which are the | |
954 | * only ones directly touching chip registers. | |
955 | * | |
956 | * This must be called from context that can sleep. | |
957 | */ | |
958 | void spi_unregister_master(struct spi_master *master) | |
959 | { | |
89fc9a1a JG |
960 | int dummy; |
961 | ||
ffbbdd21 LW |
962 | if (master->queued) { |
963 | if (spi_destroy_queue(master)) | |
964 | dev_err(&master->dev, "queue remove failed\n"); | |
965 | } | |
966 | ||
2b9603a0 FT |
967 | mutex_lock(&board_lock); |
968 | list_del(&master->list); | |
969 | mutex_unlock(&board_lock); | |
970 | ||
97dbf37d | 971 | dummy = device_for_each_child(&master->dev, NULL, __unregister); |
49dce689 | 972 | device_unregister(&master->dev); |
8ae12a0d DB |
973 | } |
974 | EXPORT_SYMBOL_GPL(spi_unregister_master); | |
975 | ||
ffbbdd21 LW |
976 | int spi_master_suspend(struct spi_master *master) |
977 | { | |
978 | int ret; | |
979 | ||
980 | /* Basically no-ops for non-queued masters */ | |
981 | if (!master->queued) | |
982 | return 0; | |
983 | ||
984 | ret = spi_stop_queue(master); | |
985 | if (ret) | |
986 | dev_err(&master->dev, "queue stop failed\n"); | |
987 | ||
988 | return ret; | |
989 | } | |
990 | EXPORT_SYMBOL_GPL(spi_master_suspend); | |
991 | ||
992 | int spi_master_resume(struct spi_master *master) | |
993 | { | |
994 | int ret; | |
995 | ||
996 | if (!master->queued) | |
997 | return 0; | |
998 | ||
999 | ret = spi_start_queue(master); | |
1000 | if (ret) | |
1001 | dev_err(&master->dev, "queue restart failed\n"); | |
1002 | ||
1003 | return ret; | |
1004 | } | |
1005 | EXPORT_SYMBOL_GPL(spi_master_resume); | |
1006 | ||
5ed2c832 DY |
1007 | static int __spi_master_match(struct device *dev, void *data) |
1008 | { | |
1009 | struct spi_master *m; | |
1010 | u16 *bus_num = data; | |
1011 | ||
1012 | m = container_of(dev, struct spi_master, dev); | |
1013 | return m->bus_num == *bus_num; | |
1014 | } | |
1015 | ||
8ae12a0d DB |
1016 | /** |
1017 | * spi_busnum_to_master - look up master associated with bus_num | |
1018 | * @bus_num: the master's bus number | |
33e34dc6 | 1019 | * Context: can sleep |
8ae12a0d DB |
1020 | * |
1021 | * This call may be used with devices that are registered after | |
1022 | * arch init time. It returns a refcounted pointer to the relevant | |
1023 | * spi_master (which the caller must release), or NULL if there is | |
1024 | * no such master registered. | |
1025 | */ | |
1026 | struct spi_master *spi_busnum_to_master(u16 bus_num) | |
1027 | { | |
49dce689 | 1028 | struct device *dev; |
1e9a51dc | 1029 | struct spi_master *master = NULL; |
5ed2c832 | 1030 | |
695794ae | 1031 | dev = class_find_device(&spi_master_class, NULL, &bus_num, |
5ed2c832 DY |
1032 | __spi_master_match); |
1033 | if (dev) | |
1034 | master = container_of(dev, struct spi_master, dev); | |
1035 | /* reference got in class_find_device */ | |
1e9a51dc | 1036 | return master; |
8ae12a0d DB |
1037 | } |
1038 | EXPORT_SYMBOL_GPL(spi_busnum_to_master); | |
1039 | ||
1040 | ||
1041 | /*-------------------------------------------------------------------------*/ | |
1042 | ||
7d077197 DB |
1043 | /* Core methods for SPI master protocol drivers. Some of the |
1044 | * other core methods are currently defined as inline functions. | |
1045 | */ | |
1046 | ||
1047 | /** | |
1048 | * spi_setup - setup SPI mode and clock rate | |
1049 | * @spi: the device whose settings are being modified | |
1050 | * Context: can sleep, and no requests are queued to the device | |
1051 | * | |
1052 | * SPI protocol drivers may need to update the transfer mode if the | |
1053 | * device doesn't work with its default. They may likewise need | |
1054 | * to update clock rates or word sizes from initial values. This function | |
1055 | * changes those settings, and must be called from a context that can sleep. | |
1056 | * Except for SPI_CS_HIGH, which takes effect immediately, the changes take | |
1057 | * effect the next time the device is selected and data is transferred to | |
1058 | * or from it. When this function returns, the spi device is deselected. | |
1059 | * | |
1060 | * Note that this call will fail if the protocol driver specifies an option | |
1061 | * that the underlying controller or its driver does not support. For | |
1062 | * example, not all hardware supports wire transfers using nine bit words, | |
1063 | * LSB-first wire encoding, or active-high chipselects. | |
1064 | */ | |
1065 | int spi_setup(struct spi_device *spi) | |
1066 | { | |
e7db06b5 | 1067 | unsigned bad_bits; |
7d077197 DB |
1068 | int status; |
1069 | ||
e7db06b5 DB |
1070 | /* help drivers fail *cleanly* when they need options |
1071 | * that aren't supported with their current master | |
1072 | */ | |
1073 | bad_bits = spi->mode & ~spi->master->mode_bits; | |
1074 | if (bad_bits) { | |
eb288a1f | 1075 | dev_err(&spi->dev, "setup: unsupported mode bits %x\n", |
e7db06b5 DB |
1076 | bad_bits); |
1077 | return -EINVAL; | |
1078 | } | |
1079 | ||
7d077197 DB |
1080 | if (!spi->bits_per_word) |
1081 | spi->bits_per_word = 8; | |
1082 | ||
1083 | status = spi->master->setup(spi); | |
1084 | ||
1085 | dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s" | |
1086 | "%u bits/w, %u Hz max --> %d\n", | |
1087 | (int) (spi->mode & (SPI_CPOL | SPI_CPHA)), | |
1088 | (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "", | |
1089 | (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "", | |
1090 | (spi->mode & SPI_3WIRE) ? "3wire, " : "", | |
1091 | (spi->mode & SPI_LOOP) ? "loopback, " : "", | |
1092 | spi->bits_per_word, spi->max_speed_hz, | |
1093 | status); | |
1094 | ||
1095 | return status; | |
1096 | } | |
1097 | EXPORT_SYMBOL_GPL(spi_setup); | |
1098 | ||
cf32b71e ES |
1099 | static int __spi_async(struct spi_device *spi, struct spi_message *message) |
1100 | { | |
1101 | struct spi_master *master = spi->master; | |
1102 | ||
1103 | /* Half-duplex links include original MicroWire, and ones with | |
1104 | * only one data pin like SPI_3WIRE (switches direction) or where | |
1105 | * either MOSI or MISO is missing. They can also be caused by | |
1106 | * software limitations. | |
1107 | */ | |
1108 | if ((master->flags & SPI_MASTER_HALF_DUPLEX) | |
1109 | || (spi->mode & SPI_3WIRE)) { | |
1110 | struct spi_transfer *xfer; | |
1111 | unsigned flags = master->flags; | |
1112 | ||
1113 | list_for_each_entry(xfer, &message->transfers, transfer_list) { | |
1114 | if (xfer->rx_buf && xfer->tx_buf) | |
1115 | return -EINVAL; | |
1116 | if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf) | |
1117 | return -EINVAL; | |
1118 | if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf) | |
1119 | return -EINVAL; | |
1120 | } | |
1121 | } | |
1122 | ||
1123 | message->spi = spi; | |
1124 | message->status = -EINPROGRESS; | |
1125 | return master->transfer(spi, message); | |
1126 | } | |
1127 | ||
568d0697 DB |
1128 | /** |
1129 | * spi_async - asynchronous SPI transfer | |
1130 | * @spi: device with which data will be exchanged | |
1131 | * @message: describes the data transfers, including completion callback | |
1132 | * Context: any (irqs may be blocked, etc) | |
1133 | * | |
1134 | * This call may be used in_irq and other contexts which can't sleep, | |
1135 | * as well as from task contexts which can sleep. | |
1136 | * | |
1137 | * The completion callback is invoked in a context which can't sleep. | |
1138 | * Before that invocation, the value of message->status is undefined. | |
1139 | * When the callback is issued, message->status holds either zero (to | |
1140 | * indicate complete success) or a negative error code. After that | |
1141 | * callback returns, the driver which issued the transfer request may | |
1142 | * deallocate the associated memory; it's no longer in use by any SPI | |
1143 | * core or controller driver code. | |
1144 | * | |
1145 | * Note that although all messages to a spi_device are handled in | |
1146 | * FIFO order, messages may go to different devices in other orders. | |
1147 | * Some device might be higher priority, or have various "hard" access | |
1148 | * time requirements, for example. | |
1149 | * | |
1150 | * On detection of any fault during the transfer, processing of | |
1151 | * the entire message is aborted, and the device is deselected. | |
1152 | * Until returning from the associated message completion callback, | |
1153 | * no other spi_message queued to that device will be processed. | |
1154 | * (This rule applies equally to all the synchronous transfer calls, | |
1155 | * which are wrappers around this core asynchronous primitive.) | |
1156 | */ | |
1157 | int spi_async(struct spi_device *spi, struct spi_message *message) | |
1158 | { | |
1159 | struct spi_master *master = spi->master; | |
cf32b71e ES |
1160 | int ret; |
1161 | unsigned long flags; | |
568d0697 | 1162 | |
cf32b71e | 1163 | spin_lock_irqsave(&master->bus_lock_spinlock, flags); |
568d0697 | 1164 | |
cf32b71e ES |
1165 | if (master->bus_lock_flag) |
1166 | ret = -EBUSY; | |
1167 | else | |
1168 | ret = __spi_async(spi, message); | |
568d0697 | 1169 | |
cf32b71e ES |
1170 | spin_unlock_irqrestore(&master->bus_lock_spinlock, flags); |
1171 | ||
1172 | return ret; | |
568d0697 DB |
1173 | } |
1174 | EXPORT_SYMBOL_GPL(spi_async); | |
1175 | ||
cf32b71e ES |
1176 | /** |
1177 | * spi_async_locked - version of spi_async with exclusive bus usage | |
1178 | * @spi: device with which data will be exchanged | |
1179 | * @message: describes the data transfers, including completion callback | |
1180 | * Context: any (irqs may be blocked, etc) | |
1181 | * | |
1182 | * This call may be used in_irq and other contexts which can't sleep, | |
1183 | * as well as from task contexts which can sleep. | |
1184 | * | |
1185 | * The completion callback is invoked in a context which can't sleep. | |
1186 | * Before that invocation, the value of message->status is undefined. | |
1187 | * When the callback is issued, message->status holds either zero (to | |
1188 | * indicate complete success) or a negative error code. After that | |
1189 | * callback returns, the driver which issued the transfer request may | |
1190 | * deallocate the associated memory; it's no longer in use by any SPI | |
1191 | * core or controller driver code. | |
1192 | * | |
1193 | * Note that although all messages to a spi_device are handled in | |
1194 | * FIFO order, messages may go to different devices in other orders. | |
1195 | * Some device might be higher priority, or have various "hard" access | |
1196 | * time requirements, for example. | |
1197 | * | |
1198 | * On detection of any fault during the transfer, processing of | |
1199 | * the entire message is aborted, and the device is deselected. | |
1200 | * Until returning from the associated message completion callback, | |
1201 | * no other spi_message queued to that device will be processed. | |
1202 | * (This rule applies equally to all the synchronous transfer calls, | |
1203 | * which are wrappers around this core asynchronous primitive.) | |
1204 | */ | |
1205 | int spi_async_locked(struct spi_device *spi, struct spi_message *message) | |
1206 | { | |
1207 | struct spi_master *master = spi->master; | |
1208 | int ret; | |
1209 | unsigned long flags; | |
1210 | ||
1211 | spin_lock_irqsave(&master->bus_lock_spinlock, flags); | |
1212 | ||
1213 | ret = __spi_async(spi, message); | |
1214 | ||
1215 | spin_unlock_irqrestore(&master->bus_lock_spinlock, flags); | |
1216 | ||
1217 | return ret; | |
1218 | ||
1219 | } | |
1220 | EXPORT_SYMBOL_GPL(spi_async_locked); | |
1221 | ||
7d077197 DB |
1222 | |
1223 | /*-------------------------------------------------------------------------*/ | |
1224 | ||
1225 | /* Utility methods for SPI master protocol drivers, layered on | |
1226 | * top of the core. Some other utility methods are defined as | |
1227 | * inline functions. | |
1228 | */ | |
1229 | ||
5d870c8e AM |
1230 | static void spi_complete(void *arg) |
1231 | { | |
1232 | complete(arg); | |
1233 | } | |
1234 | ||
cf32b71e ES |
1235 | static int __spi_sync(struct spi_device *spi, struct spi_message *message, |
1236 | int bus_locked) | |
1237 | { | |
1238 | DECLARE_COMPLETION_ONSTACK(done); | |
1239 | int status; | |
1240 | struct spi_master *master = spi->master; | |
1241 | ||
1242 | message->complete = spi_complete; | |
1243 | message->context = &done; | |
1244 | ||
1245 | if (!bus_locked) | |
1246 | mutex_lock(&master->bus_lock_mutex); | |
1247 | ||
1248 | status = spi_async_locked(spi, message); | |
1249 | ||
1250 | if (!bus_locked) | |
1251 | mutex_unlock(&master->bus_lock_mutex); | |
1252 | ||
1253 | if (status == 0) { | |
1254 | wait_for_completion(&done); | |
1255 | status = message->status; | |
1256 | } | |
1257 | message->context = NULL; | |
1258 | return status; | |
1259 | } | |
1260 | ||
8ae12a0d DB |
1261 | /** |
1262 | * spi_sync - blocking/synchronous SPI data transfers | |
1263 | * @spi: device with which data will be exchanged | |
1264 | * @message: describes the data transfers | |
33e34dc6 | 1265 | * Context: can sleep |
8ae12a0d DB |
1266 | * |
1267 | * This call may only be used from a context that may sleep. The sleep | |
1268 | * is non-interruptible, and has no timeout. Low-overhead controller | |
1269 | * drivers may DMA directly into and out of the message buffers. | |
1270 | * | |
1271 | * Note that the SPI device's chip select is active during the message, | |
1272 | * and then is normally disabled between messages. Drivers for some | |
1273 | * frequently-used devices may want to minimize costs of selecting a chip, | |
1274 | * by leaving it selected in anticipation that the next message will go | |
1275 | * to the same chip. (That may increase power usage.) | |
1276 | * | |
0c868461 DB |
1277 | * Also, the caller is guaranteeing that the memory associated with the |
1278 | * message will not be freed before this call returns. | |
1279 | * | |
9b938b74 | 1280 | * It returns zero on success, else a negative error code. |
8ae12a0d DB |
1281 | */ |
1282 | int spi_sync(struct spi_device *spi, struct spi_message *message) | |
1283 | { | |
cf32b71e | 1284 | return __spi_sync(spi, message, 0); |
8ae12a0d DB |
1285 | } |
1286 | EXPORT_SYMBOL_GPL(spi_sync); | |
1287 | ||
cf32b71e ES |
1288 | /** |
1289 | * spi_sync_locked - version of spi_sync with exclusive bus usage | |
1290 | * @spi: device with which data will be exchanged | |
1291 | * @message: describes the data transfers | |
1292 | * Context: can sleep | |
1293 | * | |
1294 | * This call may only be used from a context that may sleep. The sleep | |
1295 | * is non-interruptible, and has no timeout. Low-overhead controller | |
1296 | * drivers may DMA directly into and out of the message buffers. | |
1297 | * | |
1298 | * This call should be used by drivers that require exclusive access to the | |
25985edc | 1299 | * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must |
cf32b71e ES |
1300 | * be released by a spi_bus_unlock call when the exclusive access is over. |
1301 | * | |
1302 | * It returns zero on success, else a negative error code. | |
1303 | */ | |
1304 | int spi_sync_locked(struct spi_device *spi, struct spi_message *message) | |
1305 | { | |
1306 | return __spi_sync(spi, message, 1); | |
1307 | } | |
1308 | EXPORT_SYMBOL_GPL(spi_sync_locked); | |
1309 | ||
1310 | /** | |
1311 | * spi_bus_lock - obtain a lock for exclusive SPI bus usage | |
1312 | * @master: SPI bus master that should be locked for exclusive bus access | |
1313 | * Context: can sleep | |
1314 | * | |
1315 | * This call may only be used from a context that may sleep. The sleep | |
1316 | * is non-interruptible, and has no timeout. | |
1317 | * | |
1318 | * This call should be used by drivers that require exclusive access to the | |
1319 | * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the | |
1320 | * exclusive access is over. Data transfer must be done by spi_sync_locked | |
1321 | * and spi_async_locked calls when the SPI bus lock is held. | |
1322 | * | |
1323 | * It returns zero on success, else a negative error code. | |
1324 | */ | |
1325 | int spi_bus_lock(struct spi_master *master) | |
1326 | { | |
1327 | unsigned long flags; | |
1328 | ||
1329 | mutex_lock(&master->bus_lock_mutex); | |
1330 | ||
1331 | spin_lock_irqsave(&master->bus_lock_spinlock, flags); | |
1332 | master->bus_lock_flag = 1; | |
1333 | spin_unlock_irqrestore(&master->bus_lock_spinlock, flags); | |
1334 | ||
1335 | /* mutex remains locked until spi_bus_unlock is called */ | |
1336 | ||
1337 | return 0; | |
1338 | } | |
1339 | EXPORT_SYMBOL_GPL(spi_bus_lock); | |
1340 | ||
1341 | /** | |
1342 | * spi_bus_unlock - release the lock for exclusive SPI bus usage | |
1343 | * @master: SPI bus master that was locked for exclusive bus access | |
1344 | * Context: can sleep | |
1345 | * | |
1346 | * This call may only be used from a context that may sleep. The sleep | |
1347 | * is non-interruptible, and has no timeout. | |
1348 | * | |
1349 | * This call releases an SPI bus lock previously obtained by an spi_bus_lock | |
1350 | * call. | |
1351 | * | |
1352 | * It returns zero on success, else a negative error code. | |
1353 | */ | |
1354 | int spi_bus_unlock(struct spi_master *master) | |
1355 | { | |
1356 | master->bus_lock_flag = 0; | |
1357 | ||
1358 | mutex_unlock(&master->bus_lock_mutex); | |
1359 | ||
1360 | return 0; | |
1361 | } | |
1362 | EXPORT_SYMBOL_GPL(spi_bus_unlock); | |
1363 | ||
a9948b61 DB |
1364 | /* portable code must never pass more than 32 bytes */ |
1365 | #define SPI_BUFSIZ max(32,SMP_CACHE_BYTES) | |
8ae12a0d DB |
1366 | |
1367 | static u8 *buf; | |
1368 | ||
1369 | /** | |
1370 | * spi_write_then_read - SPI synchronous write followed by read | |
1371 | * @spi: device with which data will be exchanged | |
1372 | * @txbuf: data to be written (need not be dma-safe) | |
1373 | * @n_tx: size of txbuf, in bytes | |
27570497 JP |
1374 | * @rxbuf: buffer into which data will be read (need not be dma-safe) |
1375 | * @n_rx: size of rxbuf, in bytes | |
33e34dc6 | 1376 | * Context: can sleep |
8ae12a0d DB |
1377 | * |
1378 | * This performs a half duplex MicroWire style transaction with the | |
1379 | * device, sending txbuf and then reading rxbuf. The return value | |
1380 | * is zero for success, else a negative errno status code. | |
b885244e | 1381 | * This call may only be used from a context that may sleep. |
8ae12a0d | 1382 | * |
0c868461 | 1383 | * Parameters to this routine are always copied using a small buffer; |
33e34dc6 DB |
1384 | * portable code should never use this for more than 32 bytes. |
1385 | * Performance-sensitive or bulk transfer code should instead use | |
0c868461 | 1386 | * spi_{async,sync}() calls with dma-safe buffers. |
8ae12a0d DB |
1387 | */ |
1388 | int spi_write_then_read(struct spi_device *spi, | |
0c4a1590 MB |
1389 | const void *txbuf, unsigned n_tx, |
1390 | void *rxbuf, unsigned n_rx) | |
8ae12a0d | 1391 | { |
068f4070 | 1392 | static DEFINE_MUTEX(lock); |
8ae12a0d DB |
1393 | |
1394 | int status; | |
1395 | struct spi_message message; | |
bdff549e | 1396 | struct spi_transfer x[2]; |
8ae12a0d DB |
1397 | u8 *local_buf; |
1398 | ||
1399 | /* Use preallocated DMA-safe buffer. We can't avoid copying here, | |
1400 | * (as a pure convenience thing), but we can keep heap costs | |
1401 | * out of the hot path ... | |
1402 | */ | |
1403 | if ((n_tx + n_rx) > SPI_BUFSIZ) | |
1404 | return -EINVAL; | |
1405 | ||
8275c642 | 1406 | spi_message_init(&message); |
bdff549e DB |
1407 | memset(x, 0, sizeof x); |
1408 | if (n_tx) { | |
1409 | x[0].len = n_tx; | |
1410 | spi_message_add_tail(&x[0], &message); | |
1411 | } | |
1412 | if (n_rx) { | |
1413 | x[1].len = n_rx; | |
1414 | spi_message_add_tail(&x[1], &message); | |
1415 | } | |
8275c642 | 1416 | |
8ae12a0d | 1417 | /* ... unless someone else is using the pre-allocated buffer */ |
068f4070 | 1418 | if (!mutex_trylock(&lock)) { |
8ae12a0d DB |
1419 | local_buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL); |
1420 | if (!local_buf) | |
1421 | return -ENOMEM; | |
1422 | } else | |
1423 | local_buf = buf; | |
1424 | ||
8ae12a0d | 1425 | memcpy(local_buf, txbuf, n_tx); |
bdff549e DB |
1426 | x[0].tx_buf = local_buf; |
1427 | x[1].rx_buf = local_buf + n_tx; | |
8ae12a0d DB |
1428 | |
1429 | /* do the i/o */ | |
8ae12a0d | 1430 | status = spi_sync(spi, &message); |
9b938b74 | 1431 | if (status == 0) |
bdff549e | 1432 | memcpy(rxbuf, x[1].rx_buf, n_rx); |
8ae12a0d | 1433 | |
bdff549e | 1434 | if (x[0].tx_buf == buf) |
068f4070 | 1435 | mutex_unlock(&lock); |
8ae12a0d DB |
1436 | else |
1437 | kfree(local_buf); | |
1438 | ||
1439 | return status; | |
1440 | } | |
1441 | EXPORT_SYMBOL_GPL(spi_write_then_read); | |
1442 | ||
1443 | /*-------------------------------------------------------------------------*/ | |
1444 | ||
1445 | static int __init spi_init(void) | |
1446 | { | |
b885244e DB |
1447 | int status; |
1448 | ||
e94b1766 | 1449 | buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL); |
b885244e DB |
1450 | if (!buf) { |
1451 | status = -ENOMEM; | |
1452 | goto err0; | |
1453 | } | |
1454 | ||
1455 | status = bus_register(&spi_bus_type); | |
1456 | if (status < 0) | |
1457 | goto err1; | |
8ae12a0d | 1458 | |
b885244e DB |
1459 | status = class_register(&spi_master_class); |
1460 | if (status < 0) | |
1461 | goto err2; | |
8ae12a0d | 1462 | return 0; |
b885244e DB |
1463 | |
1464 | err2: | |
1465 | bus_unregister(&spi_bus_type); | |
1466 | err1: | |
1467 | kfree(buf); | |
1468 | buf = NULL; | |
1469 | err0: | |
1470 | return status; | |
8ae12a0d | 1471 | } |
b885244e | 1472 | |
8ae12a0d DB |
1473 | /* board_info is normally registered in arch_initcall(), |
1474 | * but even essential drivers wait till later | |
b885244e DB |
1475 | * |
1476 | * REVISIT only boardinfo really needs static linking. the rest (device and | |
1477 | * driver registration) _could_ be dynamically linked (modular) ... costs | |
1478 | * include needing to have boardinfo data structures be much more public. | |
8ae12a0d | 1479 | */ |
673c0c00 | 1480 | postcore_initcall(spi_init); |
8ae12a0d | 1481 |