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Commit | Line | Data |
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8ae12a0d | 1 | /* |
ca632f55 | 2 | * SPI init/core code |
8ae12a0d DB |
3 | * |
4 | * Copyright (C) 2005 David Brownell | |
d57a4282 | 5 | * Copyright (C) 2008 Secret Lab Technologies Ltd. |
8ae12a0d DB |
6 | * |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License as published by | |
9 | * the Free Software Foundation; either version 2 of the License, or | |
10 | * (at your option) any later version. | |
11 | * | |
12 | * This program is distributed in the hope that it will be useful, | |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | * GNU General Public License for more details. | |
16 | * | |
17 | * You should have received a copy of the GNU General Public License | |
18 | * along with this program; if not, write to the Free Software | |
19 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
20 | */ | |
21 | ||
8ae12a0d | 22 | #include <linux/kernel.h> |
d57a4282 | 23 | #include <linux/kmod.h> |
8ae12a0d DB |
24 | #include <linux/device.h> |
25 | #include <linux/init.h> | |
26 | #include <linux/cache.h> | |
94040828 | 27 | #include <linux/mutex.h> |
2b7a32f7 | 28 | #include <linux/of_device.h> |
d57a4282 | 29 | #include <linux/of_irq.h> |
5a0e3ad6 | 30 | #include <linux/slab.h> |
e0626e38 | 31 | #include <linux/mod_devicetable.h> |
8ae12a0d | 32 | #include <linux/spi/spi.h> |
3ae22e8c | 33 | #include <linux/pm_runtime.h> |
025ed130 | 34 | #include <linux/export.h> |
ffbbdd21 LW |
35 | #include <linux/sched.h> |
36 | #include <linux/delay.h> | |
37 | #include <linux/kthread.h> | |
8ae12a0d | 38 | |
8ae12a0d DB |
39 | static void spidev_release(struct device *dev) |
40 | { | |
0ffa0285 | 41 | struct spi_device *spi = to_spi_device(dev); |
8ae12a0d DB |
42 | |
43 | /* spi masters may cleanup for released devices */ | |
44 | if (spi->master->cleanup) | |
45 | spi->master->cleanup(spi); | |
46 | ||
0c868461 | 47 | spi_master_put(spi->master); |
07a389fe | 48 | kfree(spi); |
8ae12a0d DB |
49 | } |
50 | ||
51 | static ssize_t | |
52 | modalias_show(struct device *dev, struct device_attribute *a, char *buf) | |
53 | { | |
54 | const struct spi_device *spi = to_spi_device(dev); | |
55 | ||
d8e328b3 | 56 | return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias); |
8ae12a0d DB |
57 | } |
58 | ||
59 | static struct device_attribute spi_dev_attrs[] = { | |
60 | __ATTR_RO(modalias), | |
61 | __ATTR_NULL, | |
62 | }; | |
63 | ||
64 | /* modalias support makes "modprobe $MODALIAS" new-style hotplug work, | |
65 | * and the sysfs version makes coldplug work too. | |
66 | */ | |
67 | ||
75368bf6 AV |
68 | static const struct spi_device_id *spi_match_id(const struct spi_device_id *id, |
69 | const struct spi_device *sdev) | |
70 | { | |
71 | while (id->name[0]) { | |
72 | if (!strcmp(sdev->modalias, id->name)) | |
73 | return id; | |
74 | id++; | |
75 | } | |
76 | return NULL; | |
77 | } | |
78 | ||
79 | const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev) | |
80 | { | |
81 | const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver); | |
82 | ||
83 | return spi_match_id(sdrv->id_table, sdev); | |
84 | } | |
85 | EXPORT_SYMBOL_GPL(spi_get_device_id); | |
86 | ||
8ae12a0d DB |
87 | static int spi_match_device(struct device *dev, struct device_driver *drv) |
88 | { | |
89 | const struct spi_device *spi = to_spi_device(dev); | |
75368bf6 AV |
90 | const struct spi_driver *sdrv = to_spi_driver(drv); |
91 | ||
2b7a32f7 SA |
92 | /* Attempt an OF style match */ |
93 | if (of_driver_match_device(dev, drv)) | |
94 | return 1; | |
95 | ||
75368bf6 AV |
96 | if (sdrv->id_table) |
97 | return !!spi_match_id(sdrv->id_table, spi); | |
8ae12a0d | 98 | |
35f74fca | 99 | return strcmp(spi->modalias, drv->name) == 0; |
8ae12a0d DB |
100 | } |
101 | ||
7eff2e7a | 102 | static int spi_uevent(struct device *dev, struct kobj_uevent_env *env) |
8ae12a0d DB |
103 | { |
104 | const struct spi_device *spi = to_spi_device(dev); | |
105 | ||
e0626e38 | 106 | add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias); |
8ae12a0d DB |
107 | return 0; |
108 | } | |
109 | ||
3ae22e8c MB |
110 | #ifdef CONFIG_PM_SLEEP |
111 | static int spi_legacy_suspend(struct device *dev, pm_message_t message) | |
8ae12a0d | 112 | { |
3c72426f | 113 | int value = 0; |
b885244e | 114 | struct spi_driver *drv = to_spi_driver(dev->driver); |
8ae12a0d | 115 | |
8ae12a0d | 116 | /* suspend will stop irqs and dma; no more i/o */ |
3c72426f DB |
117 | if (drv) { |
118 | if (drv->suspend) | |
119 | value = drv->suspend(to_spi_device(dev), message); | |
120 | else | |
121 | dev_dbg(dev, "... can't suspend\n"); | |
122 | } | |
8ae12a0d DB |
123 | return value; |
124 | } | |
125 | ||
3ae22e8c | 126 | static int spi_legacy_resume(struct device *dev) |
8ae12a0d | 127 | { |
3c72426f | 128 | int value = 0; |
b885244e | 129 | struct spi_driver *drv = to_spi_driver(dev->driver); |
8ae12a0d | 130 | |
8ae12a0d | 131 | /* resume may restart the i/o queue */ |
3c72426f DB |
132 | if (drv) { |
133 | if (drv->resume) | |
134 | value = drv->resume(to_spi_device(dev)); | |
135 | else | |
136 | dev_dbg(dev, "... can't resume\n"); | |
137 | } | |
8ae12a0d DB |
138 | return value; |
139 | } | |
140 | ||
3ae22e8c MB |
141 | static int spi_pm_suspend(struct device *dev) |
142 | { | |
143 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
144 | ||
145 | if (pm) | |
146 | return pm_generic_suspend(dev); | |
147 | else | |
148 | return spi_legacy_suspend(dev, PMSG_SUSPEND); | |
149 | } | |
150 | ||
151 | static int spi_pm_resume(struct device *dev) | |
152 | { | |
153 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
154 | ||
155 | if (pm) | |
156 | return pm_generic_resume(dev); | |
157 | else | |
158 | return spi_legacy_resume(dev); | |
159 | } | |
160 | ||
161 | static int spi_pm_freeze(struct device *dev) | |
162 | { | |
163 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
164 | ||
165 | if (pm) | |
166 | return pm_generic_freeze(dev); | |
167 | else | |
168 | return spi_legacy_suspend(dev, PMSG_FREEZE); | |
169 | } | |
170 | ||
171 | static int spi_pm_thaw(struct device *dev) | |
172 | { | |
173 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
174 | ||
175 | if (pm) | |
176 | return pm_generic_thaw(dev); | |
177 | else | |
178 | return spi_legacy_resume(dev); | |
179 | } | |
180 | ||
181 | static int spi_pm_poweroff(struct device *dev) | |
182 | { | |
183 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
184 | ||
185 | if (pm) | |
186 | return pm_generic_poweroff(dev); | |
187 | else | |
188 | return spi_legacy_suspend(dev, PMSG_HIBERNATE); | |
189 | } | |
190 | ||
191 | static int spi_pm_restore(struct device *dev) | |
192 | { | |
193 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
194 | ||
195 | if (pm) | |
196 | return pm_generic_restore(dev); | |
197 | else | |
198 | return spi_legacy_resume(dev); | |
199 | } | |
8ae12a0d | 200 | #else |
3ae22e8c MB |
201 | #define spi_pm_suspend NULL |
202 | #define spi_pm_resume NULL | |
203 | #define spi_pm_freeze NULL | |
204 | #define spi_pm_thaw NULL | |
205 | #define spi_pm_poweroff NULL | |
206 | #define spi_pm_restore NULL | |
8ae12a0d DB |
207 | #endif |
208 | ||
3ae22e8c MB |
209 | static const struct dev_pm_ops spi_pm = { |
210 | .suspend = spi_pm_suspend, | |
211 | .resume = spi_pm_resume, | |
212 | .freeze = spi_pm_freeze, | |
213 | .thaw = spi_pm_thaw, | |
214 | .poweroff = spi_pm_poweroff, | |
215 | .restore = spi_pm_restore, | |
216 | SET_RUNTIME_PM_OPS( | |
217 | pm_generic_runtime_suspend, | |
218 | pm_generic_runtime_resume, | |
219 | pm_generic_runtime_idle | |
220 | ) | |
221 | }; | |
222 | ||
8ae12a0d DB |
223 | struct bus_type spi_bus_type = { |
224 | .name = "spi", | |
225 | .dev_attrs = spi_dev_attrs, | |
226 | .match = spi_match_device, | |
227 | .uevent = spi_uevent, | |
3ae22e8c | 228 | .pm = &spi_pm, |
8ae12a0d DB |
229 | }; |
230 | EXPORT_SYMBOL_GPL(spi_bus_type); | |
231 | ||
b885244e DB |
232 | |
233 | static int spi_drv_probe(struct device *dev) | |
234 | { | |
235 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); | |
236 | ||
237 | return sdrv->probe(to_spi_device(dev)); | |
238 | } | |
239 | ||
240 | static int spi_drv_remove(struct device *dev) | |
241 | { | |
242 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); | |
243 | ||
244 | return sdrv->remove(to_spi_device(dev)); | |
245 | } | |
246 | ||
247 | static void spi_drv_shutdown(struct device *dev) | |
248 | { | |
249 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); | |
250 | ||
251 | sdrv->shutdown(to_spi_device(dev)); | |
252 | } | |
253 | ||
33e34dc6 DB |
254 | /** |
255 | * spi_register_driver - register a SPI driver | |
256 | * @sdrv: the driver to register | |
257 | * Context: can sleep | |
258 | */ | |
b885244e DB |
259 | int spi_register_driver(struct spi_driver *sdrv) |
260 | { | |
261 | sdrv->driver.bus = &spi_bus_type; | |
262 | if (sdrv->probe) | |
263 | sdrv->driver.probe = spi_drv_probe; | |
264 | if (sdrv->remove) | |
265 | sdrv->driver.remove = spi_drv_remove; | |
266 | if (sdrv->shutdown) | |
267 | sdrv->driver.shutdown = spi_drv_shutdown; | |
268 | return driver_register(&sdrv->driver); | |
269 | } | |
270 | EXPORT_SYMBOL_GPL(spi_register_driver); | |
271 | ||
8ae12a0d DB |
272 | /*-------------------------------------------------------------------------*/ |
273 | ||
274 | /* SPI devices should normally not be created by SPI device drivers; that | |
275 | * would make them board-specific. Similarly with SPI master drivers. | |
276 | * Device registration normally goes into like arch/.../mach.../board-YYY.c | |
277 | * with other readonly (flashable) information about mainboard devices. | |
278 | */ | |
279 | ||
280 | struct boardinfo { | |
281 | struct list_head list; | |
2b9603a0 | 282 | struct spi_board_info board_info; |
8ae12a0d DB |
283 | }; |
284 | ||
285 | static LIST_HEAD(board_list); | |
2b9603a0 FT |
286 | static LIST_HEAD(spi_master_list); |
287 | ||
288 | /* | |
289 | * Used to protect add/del opertion for board_info list and | |
290 | * spi_master list, and their matching process | |
291 | */ | |
94040828 | 292 | static DEFINE_MUTEX(board_lock); |
8ae12a0d | 293 | |
dc87c98e GL |
294 | /** |
295 | * spi_alloc_device - Allocate a new SPI device | |
296 | * @master: Controller to which device is connected | |
297 | * Context: can sleep | |
298 | * | |
299 | * Allows a driver to allocate and initialize a spi_device without | |
300 | * registering it immediately. This allows a driver to directly | |
301 | * fill the spi_device with device parameters before calling | |
302 | * spi_add_device() on it. | |
303 | * | |
304 | * Caller is responsible to call spi_add_device() on the returned | |
305 | * spi_device structure to add it to the SPI master. If the caller | |
306 | * needs to discard the spi_device without adding it, then it should | |
307 | * call spi_dev_put() on it. | |
308 | * | |
309 | * Returns a pointer to the new device, or NULL. | |
310 | */ | |
311 | struct spi_device *spi_alloc_device(struct spi_master *master) | |
312 | { | |
313 | struct spi_device *spi; | |
314 | struct device *dev = master->dev.parent; | |
315 | ||
316 | if (!spi_master_get(master)) | |
317 | return NULL; | |
318 | ||
319 | spi = kzalloc(sizeof *spi, GFP_KERNEL); | |
320 | if (!spi) { | |
321 | dev_err(dev, "cannot alloc spi_device\n"); | |
322 | spi_master_put(master); | |
323 | return NULL; | |
324 | } | |
325 | ||
326 | spi->master = master; | |
178db7d3 | 327 | spi->dev.parent = &master->dev; |
dc87c98e GL |
328 | spi->dev.bus = &spi_bus_type; |
329 | spi->dev.release = spidev_release; | |
330 | device_initialize(&spi->dev); | |
331 | return spi; | |
332 | } | |
333 | EXPORT_SYMBOL_GPL(spi_alloc_device); | |
334 | ||
335 | /** | |
336 | * spi_add_device - Add spi_device allocated with spi_alloc_device | |
337 | * @spi: spi_device to register | |
338 | * | |
339 | * Companion function to spi_alloc_device. Devices allocated with | |
340 | * spi_alloc_device can be added onto the spi bus with this function. | |
341 | * | |
e48880e0 | 342 | * Returns 0 on success; negative errno on failure |
dc87c98e GL |
343 | */ |
344 | int spi_add_device(struct spi_device *spi) | |
345 | { | |
e48880e0 | 346 | static DEFINE_MUTEX(spi_add_lock); |
dc87c98e | 347 | struct device *dev = spi->master->dev.parent; |
8ec130a0 | 348 | struct device *d; |
dc87c98e GL |
349 | int status; |
350 | ||
351 | /* Chipselects are numbered 0..max; validate. */ | |
352 | if (spi->chip_select >= spi->master->num_chipselect) { | |
353 | dev_err(dev, "cs%d >= max %d\n", | |
354 | spi->chip_select, | |
355 | spi->master->num_chipselect); | |
356 | return -EINVAL; | |
357 | } | |
358 | ||
359 | /* Set the bus ID string */ | |
35f74fca | 360 | dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev), |
dc87c98e GL |
361 | spi->chip_select); |
362 | ||
e48880e0 DB |
363 | |
364 | /* We need to make sure there's no other device with this | |
365 | * chipselect **BEFORE** we call setup(), else we'll trash | |
366 | * its configuration. Lock against concurrent add() calls. | |
367 | */ | |
368 | mutex_lock(&spi_add_lock); | |
369 | ||
8ec130a0 RT |
370 | d = bus_find_device_by_name(&spi_bus_type, NULL, dev_name(&spi->dev)); |
371 | if (d != NULL) { | |
e48880e0 DB |
372 | dev_err(dev, "chipselect %d already in use\n", |
373 | spi->chip_select); | |
8ec130a0 | 374 | put_device(d); |
e48880e0 DB |
375 | status = -EBUSY; |
376 | goto done; | |
377 | } | |
378 | ||
379 | /* Drivers may modify this initial i/o setup, but will | |
380 | * normally rely on the device being setup. Devices | |
381 | * using SPI_CS_HIGH can't coexist well otherwise... | |
382 | */ | |
7d077197 | 383 | status = spi_setup(spi); |
dc87c98e | 384 | if (status < 0) { |
eb288a1f LW |
385 | dev_err(dev, "can't setup %s, status %d\n", |
386 | dev_name(&spi->dev), status); | |
e48880e0 | 387 | goto done; |
dc87c98e GL |
388 | } |
389 | ||
e48880e0 | 390 | /* Device may be bound to an active driver when this returns */ |
dc87c98e | 391 | status = device_add(&spi->dev); |
e48880e0 | 392 | if (status < 0) |
eb288a1f LW |
393 | dev_err(dev, "can't add %s, status %d\n", |
394 | dev_name(&spi->dev), status); | |
e48880e0 | 395 | else |
35f74fca | 396 | dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev)); |
dc87c98e | 397 | |
e48880e0 DB |
398 | done: |
399 | mutex_unlock(&spi_add_lock); | |
400 | return status; | |
dc87c98e GL |
401 | } |
402 | EXPORT_SYMBOL_GPL(spi_add_device); | |
8ae12a0d | 403 | |
33e34dc6 DB |
404 | /** |
405 | * spi_new_device - instantiate one new SPI device | |
406 | * @master: Controller to which device is connected | |
407 | * @chip: Describes the SPI device | |
408 | * Context: can sleep | |
409 | * | |
410 | * On typical mainboards, this is purely internal; and it's not needed | |
8ae12a0d DB |
411 | * after board init creates the hard-wired devices. Some development |
412 | * platforms may not be able to use spi_register_board_info though, and | |
413 | * this is exported so that for example a USB or parport based adapter | |
414 | * driver could add devices (which it would learn about out-of-band). | |
082c8cb4 DB |
415 | * |
416 | * Returns the new device, or NULL. | |
8ae12a0d | 417 | */ |
e9d5a461 AB |
418 | struct spi_device *spi_new_device(struct spi_master *master, |
419 | struct spi_board_info *chip) | |
8ae12a0d DB |
420 | { |
421 | struct spi_device *proxy; | |
8ae12a0d DB |
422 | int status; |
423 | ||
082c8cb4 DB |
424 | /* NOTE: caller did any chip->bus_num checks necessary. |
425 | * | |
426 | * Also, unless we change the return value convention to use | |
427 | * error-or-pointer (not NULL-or-pointer), troubleshootability | |
428 | * suggests syslogged diagnostics are best here (ugh). | |
429 | */ | |
430 | ||
dc87c98e GL |
431 | proxy = spi_alloc_device(master); |
432 | if (!proxy) | |
8ae12a0d DB |
433 | return NULL; |
434 | ||
102eb975 GL |
435 | WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias)); |
436 | ||
8ae12a0d DB |
437 | proxy->chip_select = chip->chip_select; |
438 | proxy->max_speed_hz = chip->max_speed_hz; | |
980a01c9 | 439 | proxy->mode = chip->mode; |
8ae12a0d | 440 | proxy->irq = chip->irq; |
102eb975 | 441 | strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias)); |
8ae12a0d DB |
442 | proxy->dev.platform_data = (void *) chip->platform_data; |
443 | proxy->controller_data = chip->controller_data; | |
444 | proxy->controller_state = NULL; | |
8ae12a0d | 445 | |
dc87c98e | 446 | status = spi_add_device(proxy); |
8ae12a0d | 447 | if (status < 0) { |
dc87c98e GL |
448 | spi_dev_put(proxy); |
449 | return NULL; | |
8ae12a0d DB |
450 | } |
451 | ||
8ae12a0d DB |
452 | return proxy; |
453 | } | |
454 | EXPORT_SYMBOL_GPL(spi_new_device); | |
455 | ||
2b9603a0 FT |
456 | static void spi_match_master_to_boardinfo(struct spi_master *master, |
457 | struct spi_board_info *bi) | |
458 | { | |
459 | struct spi_device *dev; | |
460 | ||
461 | if (master->bus_num != bi->bus_num) | |
462 | return; | |
463 | ||
464 | dev = spi_new_device(master, bi); | |
465 | if (!dev) | |
466 | dev_err(master->dev.parent, "can't create new device for %s\n", | |
467 | bi->modalias); | |
468 | } | |
469 | ||
33e34dc6 DB |
470 | /** |
471 | * spi_register_board_info - register SPI devices for a given board | |
472 | * @info: array of chip descriptors | |
473 | * @n: how many descriptors are provided | |
474 | * Context: can sleep | |
475 | * | |
8ae12a0d DB |
476 | * Board-specific early init code calls this (probably during arch_initcall) |
477 | * with segments of the SPI device table. Any device nodes are created later, | |
478 | * after the relevant parent SPI controller (bus_num) is defined. We keep | |
479 | * this table of devices forever, so that reloading a controller driver will | |
480 | * not make Linux forget about these hard-wired devices. | |
481 | * | |
482 | * Other code can also call this, e.g. a particular add-on board might provide | |
483 | * SPI devices through its expansion connector, so code initializing that board | |
484 | * would naturally declare its SPI devices. | |
485 | * | |
486 | * The board info passed can safely be __initdata ... but be careful of | |
487 | * any embedded pointers (platform_data, etc), they're copied as-is. | |
488 | */ | |
690fb11b | 489 | int __devinit |
8ae12a0d DB |
490 | spi_register_board_info(struct spi_board_info const *info, unsigned n) |
491 | { | |
2b9603a0 FT |
492 | struct boardinfo *bi; |
493 | int i; | |
8ae12a0d | 494 | |
2b9603a0 | 495 | bi = kzalloc(n * sizeof(*bi), GFP_KERNEL); |
8ae12a0d DB |
496 | if (!bi) |
497 | return -ENOMEM; | |
8ae12a0d | 498 | |
2b9603a0 FT |
499 | for (i = 0; i < n; i++, bi++, info++) { |
500 | struct spi_master *master; | |
8ae12a0d | 501 | |
2b9603a0 FT |
502 | memcpy(&bi->board_info, info, sizeof(*info)); |
503 | mutex_lock(&board_lock); | |
504 | list_add_tail(&bi->list, &board_list); | |
505 | list_for_each_entry(master, &spi_master_list, list) | |
506 | spi_match_master_to_boardinfo(master, &bi->board_info); | |
507 | mutex_unlock(&board_lock); | |
8ae12a0d | 508 | } |
2b9603a0 FT |
509 | |
510 | return 0; | |
8ae12a0d DB |
511 | } |
512 | ||
513 | /*-------------------------------------------------------------------------*/ | |
514 | ||
ffbbdd21 LW |
515 | /** |
516 | * spi_pump_messages - kthread work function which processes spi message queue | |
517 | * @work: pointer to kthread work struct contained in the master struct | |
518 | * | |
519 | * This function checks if there is any spi message in the queue that | |
520 | * needs processing and if so call out to the driver to initialize hardware | |
521 | * and transfer each message. | |
522 | * | |
523 | */ | |
524 | static void spi_pump_messages(struct kthread_work *work) | |
525 | { | |
526 | struct spi_master *master = | |
527 | container_of(work, struct spi_master, pump_messages); | |
528 | unsigned long flags; | |
529 | bool was_busy = false; | |
530 | int ret; | |
531 | ||
532 | /* Lock queue and check for queue work */ | |
533 | spin_lock_irqsave(&master->queue_lock, flags); | |
534 | if (list_empty(&master->queue) || !master->running) { | |
7dfd2bd7 | 535 | if (master->busy && master->unprepare_transfer_hardware) { |
ffbbdd21 LW |
536 | ret = master->unprepare_transfer_hardware(master); |
537 | if (ret) { | |
9af4acc0 | 538 | spin_unlock_irqrestore(&master->queue_lock, flags); |
ffbbdd21 LW |
539 | dev_err(&master->dev, |
540 | "failed to unprepare transfer hardware\n"); | |
541 | return; | |
542 | } | |
543 | } | |
544 | master->busy = false; | |
545 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
546 | return; | |
547 | } | |
548 | ||
549 | /* Make sure we are not already running a message */ | |
550 | if (master->cur_msg) { | |
551 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
552 | return; | |
553 | } | |
554 | /* Extract head of queue */ | |
555 | master->cur_msg = | |
556 | list_entry(master->queue.next, struct spi_message, queue); | |
557 | ||
558 | list_del_init(&master->cur_msg->queue); | |
559 | if (master->busy) | |
560 | was_busy = true; | |
561 | else | |
562 | master->busy = true; | |
563 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
564 | ||
7dfd2bd7 | 565 | if (!was_busy && master->prepare_transfer_hardware) { |
ffbbdd21 LW |
566 | ret = master->prepare_transfer_hardware(master); |
567 | if (ret) { | |
568 | dev_err(&master->dev, | |
569 | "failed to prepare transfer hardware\n"); | |
570 | return; | |
571 | } | |
572 | } | |
573 | ||
574 | ret = master->transfer_one_message(master, master->cur_msg); | |
575 | if (ret) { | |
576 | dev_err(&master->dev, | |
577 | "failed to transfer one message from queue\n"); | |
578 | return; | |
579 | } | |
580 | } | |
581 | ||
582 | static int spi_init_queue(struct spi_master *master) | |
583 | { | |
584 | struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 }; | |
585 | ||
586 | INIT_LIST_HEAD(&master->queue); | |
587 | spin_lock_init(&master->queue_lock); | |
588 | ||
589 | master->running = false; | |
590 | master->busy = false; | |
591 | ||
592 | init_kthread_worker(&master->kworker); | |
593 | master->kworker_task = kthread_run(kthread_worker_fn, | |
594 | &master->kworker, | |
595 | dev_name(&master->dev)); | |
596 | if (IS_ERR(master->kworker_task)) { | |
597 | dev_err(&master->dev, "failed to create message pump task\n"); | |
598 | return -ENOMEM; | |
599 | } | |
600 | init_kthread_work(&master->pump_messages, spi_pump_messages); | |
601 | ||
602 | /* | |
603 | * Master config will indicate if this controller should run the | |
604 | * message pump with high (realtime) priority to reduce the transfer | |
605 | * latency on the bus by minimising the delay between a transfer | |
606 | * request and the scheduling of the message pump thread. Without this | |
607 | * setting the message pump thread will remain at default priority. | |
608 | */ | |
609 | if (master->rt) { | |
610 | dev_info(&master->dev, | |
611 | "will run message pump with realtime priority\n"); | |
612 | sched_setscheduler(master->kworker_task, SCHED_FIFO, ¶m); | |
613 | } | |
614 | ||
615 | return 0; | |
616 | } | |
617 | ||
618 | /** | |
619 | * spi_get_next_queued_message() - called by driver to check for queued | |
620 | * messages | |
621 | * @master: the master to check for queued messages | |
622 | * | |
623 | * If there are more messages in the queue, the next message is returned from | |
624 | * this call. | |
625 | */ | |
626 | struct spi_message *spi_get_next_queued_message(struct spi_master *master) | |
627 | { | |
628 | struct spi_message *next; | |
629 | unsigned long flags; | |
630 | ||
631 | /* get a pointer to the next message, if any */ | |
632 | spin_lock_irqsave(&master->queue_lock, flags); | |
633 | if (list_empty(&master->queue)) | |
634 | next = NULL; | |
635 | else | |
636 | next = list_entry(master->queue.next, | |
637 | struct spi_message, queue); | |
638 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
639 | ||
640 | return next; | |
641 | } | |
642 | EXPORT_SYMBOL_GPL(spi_get_next_queued_message); | |
643 | ||
644 | /** | |
645 | * spi_finalize_current_message() - the current message is complete | |
646 | * @master: the master to return the message to | |
647 | * | |
648 | * Called by the driver to notify the core that the message in the front of the | |
649 | * queue is complete and can be removed from the queue. | |
650 | */ | |
651 | void spi_finalize_current_message(struct spi_master *master) | |
652 | { | |
653 | struct spi_message *mesg; | |
654 | unsigned long flags; | |
655 | ||
656 | spin_lock_irqsave(&master->queue_lock, flags); | |
657 | mesg = master->cur_msg; | |
658 | master->cur_msg = NULL; | |
659 | ||
660 | queue_kthread_work(&master->kworker, &master->pump_messages); | |
661 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
662 | ||
663 | mesg->state = NULL; | |
664 | if (mesg->complete) | |
665 | mesg->complete(mesg->context); | |
666 | } | |
667 | EXPORT_SYMBOL_GPL(spi_finalize_current_message); | |
668 | ||
669 | static int spi_start_queue(struct spi_master *master) | |
670 | { | |
671 | unsigned long flags; | |
672 | ||
673 | spin_lock_irqsave(&master->queue_lock, flags); | |
674 | ||
675 | if (master->running || master->busy) { | |
676 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
677 | return -EBUSY; | |
678 | } | |
679 | ||
680 | master->running = true; | |
681 | master->cur_msg = NULL; | |
682 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
683 | ||
684 | queue_kthread_work(&master->kworker, &master->pump_messages); | |
685 | ||
686 | return 0; | |
687 | } | |
688 | ||
689 | static int spi_stop_queue(struct spi_master *master) | |
690 | { | |
691 | unsigned long flags; | |
692 | unsigned limit = 500; | |
693 | int ret = 0; | |
694 | ||
695 | spin_lock_irqsave(&master->queue_lock, flags); | |
696 | ||
697 | /* | |
698 | * This is a bit lame, but is optimized for the common execution path. | |
699 | * A wait_queue on the master->busy could be used, but then the common | |
700 | * execution path (pump_messages) would be required to call wake_up or | |
701 | * friends on every SPI message. Do this instead. | |
702 | */ | |
703 | while ((!list_empty(&master->queue) || master->busy) && limit--) { | |
704 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
705 | msleep(10); | |
706 | spin_lock_irqsave(&master->queue_lock, flags); | |
707 | } | |
708 | ||
709 | if (!list_empty(&master->queue) || master->busy) | |
710 | ret = -EBUSY; | |
711 | else | |
712 | master->running = false; | |
713 | ||
714 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
715 | ||
716 | if (ret) { | |
717 | dev_warn(&master->dev, | |
718 | "could not stop message queue\n"); | |
719 | return ret; | |
720 | } | |
721 | return ret; | |
722 | } | |
723 | ||
724 | static int spi_destroy_queue(struct spi_master *master) | |
725 | { | |
726 | int ret; | |
727 | ||
728 | ret = spi_stop_queue(master); | |
729 | ||
730 | /* | |
731 | * flush_kthread_worker will block until all work is done. | |
732 | * If the reason that stop_queue timed out is that the work will never | |
733 | * finish, then it does no good to call flush/stop thread, so | |
734 | * return anyway. | |
735 | */ | |
736 | if (ret) { | |
737 | dev_err(&master->dev, "problem destroying queue\n"); | |
738 | return ret; | |
739 | } | |
740 | ||
741 | flush_kthread_worker(&master->kworker); | |
742 | kthread_stop(master->kworker_task); | |
743 | ||
744 | return 0; | |
745 | } | |
746 | ||
747 | /** | |
748 | * spi_queued_transfer - transfer function for queued transfers | |
749 | * @spi: spi device which is requesting transfer | |
750 | * @msg: spi message which is to handled is queued to driver queue | |
751 | */ | |
752 | static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg) | |
753 | { | |
754 | struct spi_master *master = spi->master; | |
755 | unsigned long flags; | |
756 | ||
757 | spin_lock_irqsave(&master->queue_lock, flags); | |
758 | ||
759 | if (!master->running) { | |
760 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
761 | return -ESHUTDOWN; | |
762 | } | |
763 | msg->actual_length = 0; | |
764 | msg->status = -EINPROGRESS; | |
765 | ||
766 | list_add_tail(&msg->queue, &master->queue); | |
767 | if (master->running && !master->busy) | |
768 | queue_kthread_work(&master->kworker, &master->pump_messages); | |
769 | ||
770 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
771 | return 0; | |
772 | } | |
773 | ||
774 | static int spi_master_initialize_queue(struct spi_master *master) | |
775 | { | |
776 | int ret; | |
777 | ||
778 | master->queued = true; | |
779 | master->transfer = spi_queued_transfer; | |
780 | ||
781 | /* Initialize and start queue */ | |
782 | ret = spi_init_queue(master); | |
783 | if (ret) { | |
784 | dev_err(&master->dev, "problem initializing queue\n"); | |
785 | goto err_init_queue; | |
786 | } | |
787 | ret = spi_start_queue(master); | |
788 | if (ret) { | |
789 | dev_err(&master->dev, "problem starting queue\n"); | |
790 | goto err_start_queue; | |
791 | } | |
792 | ||
793 | return 0; | |
794 | ||
795 | err_start_queue: | |
796 | err_init_queue: | |
797 | spi_destroy_queue(master); | |
798 | return ret; | |
799 | } | |
800 | ||
801 | /*-------------------------------------------------------------------------*/ | |
802 | ||
d57a4282 GL |
803 | #if defined(CONFIG_OF) && !defined(CONFIG_SPARC) |
804 | /** | |
805 | * of_register_spi_devices() - Register child devices onto the SPI bus | |
806 | * @master: Pointer to spi_master device | |
807 | * | |
808 | * Registers an spi_device for each child node of master node which has a 'reg' | |
809 | * property. | |
810 | */ | |
811 | static void of_register_spi_devices(struct spi_master *master) | |
812 | { | |
813 | struct spi_device *spi; | |
814 | struct device_node *nc; | |
815 | const __be32 *prop; | |
816 | int rc; | |
817 | int len; | |
818 | ||
819 | if (!master->dev.of_node) | |
820 | return; | |
821 | ||
822 | for_each_child_of_node(master->dev.of_node, nc) { | |
823 | /* Alloc an spi_device */ | |
824 | spi = spi_alloc_device(master); | |
825 | if (!spi) { | |
826 | dev_err(&master->dev, "spi_device alloc error for %s\n", | |
827 | nc->full_name); | |
828 | spi_dev_put(spi); | |
829 | continue; | |
830 | } | |
831 | ||
832 | /* Select device driver */ | |
833 | if (of_modalias_node(nc, spi->modalias, | |
834 | sizeof(spi->modalias)) < 0) { | |
835 | dev_err(&master->dev, "cannot find modalias for %s\n", | |
836 | nc->full_name); | |
837 | spi_dev_put(spi); | |
838 | continue; | |
839 | } | |
840 | ||
841 | /* Device address */ | |
842 | prop = of_get_property(nc, "reg", &len); | |
843 | if (!prop || len < sizeof(*prop)) { | |
844 | dev_err(&master->dev, "%s has no 'reg' property\n", | |
845 | nc->full_name); | |
846 | spi_dev_put(spi); | |
847 | continue; | |
848 | } | |
849 | spi->chip_select = be32_to_cpup(prop); | |
850 | ||
851 | /* Mode (clock phase/polarity/etc.) */ | |
852 | if (of_find_property(nc, "spi-cpha", NULL)) | |
853 | spi->mode |= SPI_CPHA; | |
854 | if (of_find_property(nc, "spi-cpol", NULL)) | |
855 | spi->mode |= SPI_CPOL; | |
856 | if (of_find_property(nc, "spi-cs-high", NULL)) | |
857 | spi->mode |= SPI_CS_HIGH; | |
858 | ||
859 | /* Device speed */ | |
860 | prop = of_get_property(nc, "spi-max-frequency", &len); | |
861 | if (!prop || len < sizeof(*prop)) { | |
862 | dev_err(&master->dev, "%s has no 'spi-max-frequency' property\n", | |
863 | nc->full_name); | |
864 | spi_dev_put(spi); | |
865 | continue; | |
866 | } | |
867 | spi->max_speed_hz = be32_to_cpup(prop); | |
868 | ||
869 | /* IRQ */ | |
870 | spi->irq = irq_of_parse_and_map(nc, 0); | |
871 | ||
872 | /* Store a pointer to the node in the device structure */ | |
873 | of_node_get(nc); | |
874 | spi->dev.of_node = nc; | |
875 | ||
876 | /* Register the new device */ | |
877 | request_module(spi->modalias); | |
878 | rc = spi_add_device(spi); | |
879 | if (rc) { | |
880 | dev_err(&master->dev, "spi_device register error %s\n", | |
881 | nc->full_name); | |
882 | spi_dev_put(spi); | |
883 | } | |
884 | ||
885 | } | |
886 | } | |
887 | #else | |
888 | static void of_register_spi_devices(struct spi_master *master) { } | |
889 | #endif | |
890 | ||
49dce689 | 891 | static void spi_master_release(struct device *dev) |
8ae12a0d DB |
892 | { |
893 | struct spi_master *master; | |
894 | ||
49dce689 | 895 | master = container_of(dev, struct spi_master, dev); |
8ae12a0d DB |
896 | kfree(master); |
897 | } | |
898 | ||
899 | static struct class spi_master_class = { | |
900 | .name = "spi_master", | |
901 | .owner = THIS_MODULE, | |
49dce689 | 902 | .dev_release = spi_master_release, |
8ae12a0d DB |
903 | }; |
904 | ||
905 | ||
ffbbdd21 | 906 | |
8ae12a0d DB |
907 | /** |
908 | * spi_alloc_master - allocate SPI master controller | |
909 | * @dev: the controller, possibly using the platform_bus | |
33e34dc6 | 910 | * @size: how much zeroed driver-private data to allocate; the pointer to this |
49dce689 | 911 | * memory is in the driver_data field of the returned device, |
0c868461 | 912 | * accessible with spi_master_get_devdata(). |
33e34dc6 | 913 | * Context: can sleep |
8ae12a0d DB |
914 | * |
915 | * This call is used only by SPI master controller drivers, which are the | |
916 | * only ones directly touching chip registers. It's how they allocate | |
ba1a0513 | 917 | * an spi_master structure, prior to calling spi_register_master(). |
8ae12a0d DB |
918 | * |
919 | * This must be called from context that can sleep. It returns the SPI | |
920 | * master structure on success, else NULL. | |
921 | * | |
922 | * The caller is responsible for assigning the bus number and initializing | |
ba1a0513 | 923 | * the master's methods before calling spi_register_master(); and (after errors |
eb4af0f5 UKK |
924 | * adding the device) calling spi_master_put() and kfree() to prevent a memory |
925 | * leak. | |
8ae12a0d | 926 | */ |
e9d5a461 | 927 | struct spi_master *spi_alloc_master(struct device *dev, unsigned size) |
8ae12a0d DB |
928 | { |
929 | struct spi_master *master; | |
930 | ||
0c868461 DB |
931 | if (!dev) |
932 | return NULL; | |
933 | ||
e94b1766 | 934 | master = kzalloc(size + sizeof *master, GFP_KERNEL); |
8ae12a0d DB |
935 | if (!master) |
936 | return NULL; | |
937 | ||
49dce689 | 938 | device_initialize(&master->dev); |
1e8a52e1 GL |
939 | master->bus_num = -1; |
940 | master->num_chipselect = 1; | |
49dce689 TJ |
941 | master->dev.class = &spi_master_class; |
942 | master->dev.parent = get_device(dev); | |
0c868461 | 943 | spi_master_set_devdata(master, &master[1]); |
8ae12a0d DB |
944 | |
945 | return master; | |
946 | } | |
947 | EXPORT_SYMBOL_GPL(spi_alloc_master); | |
948 | ||
949 | /** | |
950 | * spi_register_master - register SPI master controller | |
951 | * @master: initialized master, originally from spi_alloc_master() | |
33e34dc6 | 952 | * Context: can sleep |
8ae12a0d DB |
953 | * |
954 | * SPI master controllers connect to their drivers using some non-SPI bus, | |
955 | * such as the platform bus. The final stage of probe() in that code | |
956 | * includes calling spi_register_master() to hook up to this SPI bus glue. | |
957 | * | |
958 | * SPI controllers use board specific (often SOC specific) bus numbers, | |
959 | * and board-specific addressing for SPI devices combines those numbers | |
960 | * with chip select numbers. Since SPI does not directly support dynamic | |
961 | * device identification, boards need configuration tables telling which | |
962 | * chip is at which address. | |
963 | * | |
964 | * This must be called from context that can sleep. It returns zero on | |
965 | * success, else a negative error code (dropping the master's refcount). | |
0c868461 DB |
966 | * After a successful return, the caller is responsible for calling |
967 | * spi_unregister_master(). | |
8ae12a0d | 968 | */ |
e9d5a461 | 969 | int spi_register_master(struct spi_master *master) |
8ae12a0d | 970 | { |
e44a45ae | 971 | static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1); |
49dce689 | 972 | struct device *dev = master->dev.parent; |
2b9603a0 | 973 | struct boardinfo *bi; |
8ae12a0d DB |
974 | int status = -ENODEV; |
975 | int dynamic = 0; | |
976 | ||
0c868461 DB |
977 | if (!dev) |
978 | return -ENODEV; | |
979 | ||
082c8cb4 DB |
980 | /* even if it's just one always-selected device, there must |
981 | * be at least one chipselect | |
982 | */ | |
983 | if (master->num_chipselect == 0) | |
984 | return -EINVAL; | |
985 | ||
8ae12a0d | 986 | /* convention: dynamically assigned bus IDs count down from the max */ |
a020ed75 | 987 | if (master->bus_num < 0) { |
082c8cb4 DB |
988 | /* FIXME switch to an IDR based scheme, something like |
989 | * I2C now uses, so we can't run out of "dynamic" IDs | |
990 | */ | |
8ae12a0d | 991 | master->bus_num = atomic_dec_return(&dyn_bus_id); |
b885244e | 992 | dynamic = 1; |
8ae12a0d DB |
993 | } |
994 | ||
cf32b71e ES |
995 | spin_lock_init(&master->bus_lock_spinlock); |
996 | mutex_init(&master->bus_lock_mutex); | |
997 | master->bus_lock_flag = 0; | |
998 | ||
8ae12a0d DB |
999 | /* register the device, then userspace will see it. |
1000 | * registration fails if the bus ID is in use. | |
1001 | */ | |
35f74fca | 1002 | dev_set_name(&master->dev, "spi%u", master->bus_num); |
49dce689 | 1003 | status = device_add(&master->dev); |
b885244e | 1004 | if (status < 0) |
8ae12a0d | 1005 | goto done; |
35f74fca | 1006 | dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev), |
8ae12a0d DB |
1007 | dynamic ? " (dynamic)" : ""); |
1008 | ||
ffbbdd21 LW |
1009 | /* If we're using a queued driver, start the queue */ |
1010 | if (master->transfer) | |
1011 | dev_info(dev, "master is unqueued, this is deprecated\n"); | |
1012 | else { | |
1013 | status = spi_master_initialize_queue(master); | |
1014 | if (status) { | |
1015 | device_unregister(&master->dev); | |
1016 | goto done; | |
1017 | } | |
1018 | } | |
1019 | ||
2b9603a0 FT |
1020 | mutex_lock(&board_lock); |
1021 | list_add_tail(&master->list, &spi_master_list); | |
1022 | list_for_each_entry(bi, &board_list, list) | |
1023 | spi_match_master_to_boardinfo(master, &bi->board_info); | |
1024 | mutex_unlock(&board_lock); | |
1025 | ||
12b15e83 AG |
1026 | /* Register devices from the device tree */ |
1027 | of_register_spi_devices(master); | |
8ae12a0d DB |
1028 | done: |
1029 | return status; | |
1030 | } | |
1031 | EXPORT_SYMBOL_GPL(spi_register_master); | |
1032 | ||
34860089 | 1033 | static int __unregister(struct device *dev, void *null) |
8ae12a0d | 1034 | { |
34860089 | 1035 | spi_unregister_device(to_spi_device(dev)); |
8ae12a0d DB |
1036 | return 0; |
1037 | } | |
1038 | ||
1039 | /** | |
1040 | * spi_unregister_master - unregister SPI master controller | |
1041 | * @master: the master being unregistered | |
33e34dc6 | 1042 | * Context: can sleep |
8ae12a0d DB |
1043 | * |
1044 | * This call is used only by SPI master controller drivers, which are the | |
1045 | * only ones directly touching chip registers. | |
1046 | * | |
1047 | * This must be called from context that can sleep. | |
1048 | */ | |
1049 | void spi_unregister_master(struct spi_master *master) | |
1050 | { | |
89fc9a1a JG |
1051 | int dummy; |
1052 | ||
ffbbdd21 LW |
1053 | if (master->queued) { |
1054 | if (spi_destroy_queue(master)) | |
1055 | dev_err(&master->dev, "queue remove failed\n"); | |
1056 | } | |
1057 | ||
2b9603a0 FT |
1058 | mutex_lock(&board_lock); |
1059 | list_del(&master->list); | |
1060 | mutex_unlock(&board_lock); | |
1061 | ||
97dbf37d | 1062 | dummy = device_for_each_child(&master->dev, NULL, __unregister); |
49dce689 | 1063 | device_unregister(&master->dev); |
8ae12a0d DB |
1064 | } |
1065 | EXPORT_SYMBOL_GPL(spi_unregister_master); | |
1066 | ||
ffbbdd21 LW |
1067 | int spi_master_suspend(struct spi_master *master) |
1068 | { | |
1069 | int ret; | |
1070 | ||
1071 | /* Basically no-ops for non-queued masters */ | |
1072 | if (!master->queued) | |
1073 | return 0; | |
1074 | ||
1075 | ret = spi_stop_queue(master); | |
1076 | if (ret) | |
1077 | dev_err(&master->dev, "queue stop failed\n"); | |
1078 | ||
1079 | return ret; | |
1080 | } | |
1081 | EXPORT_SYMBOL_GPL(spi_master_suspend); | |
1082 | ||
1083 | int spi_master_resume(struct spi_master *master) | |
1084 | { | |
1085 | int ret; | |
1086 | ||
1087 | if (!master->queued) | |
1088 | return 0; | |
1089 | ||
1090 | ret = spi_start_queue(master); | |
1091 | if (ret) | |
1092 | dev_err(&master->dev, "queue restart failed\n"); | |
1093 | ||
1094 | return ret; | |
1095 | } | |
1096 | EXPORT_SYMBOL_GPL(spi_master_resume); | |
1097 | ||
5ed2c832 DY |
1098 | static int __spi_master_match(struct device *dev, void *data) |
1099 | { | |
1100 | struct spi_master *m; | |
1101 | u16 *bus_num = data; | |
1102 | ||
1103 | m = container_of(dev, struct spi_master, dev); | |
1104 | return m->bus_num == *bus_num; | |
1105 | } | |
1106 | ||
8ae12a0d DB |
1107 | /** |
1108 | * spi_busnum_to_master - look up master associated with bus_num | |
1109 | * @bus_num: the master's bus number | |
33e34dc6 | 1110 | * Context: can sleep |
8ae12a0d DB |
1111 | * |
1112 | * This call may be used with devices that are registered after | |
1113 | * arch init time. It returns a refcounted pointer to the relevant | |
1114 | * spi_master (which the caller must release), or NULL if there is | |
1115 | * no such master registered. | |
1116 | */ | |
1117 | struct spi_master *spi_busnum_to_master(u16 bus_num) | |
1118 | { | |
49dce689 | 1119 | struct device *dev; |
1e9a51dc | 1120 | struct spi_master *master = NULL; |
5ed2c832 | 1121 | |
695794ae | 1122 | dev = class_find_device(&spi_master_class, NULL, &bus_num, |
5ed2c832 DY |
1123 | __spi_master_match); |
1124 | if (dev) | |
1125 | master = container_of(dev, struct spi_master, dev); | |
1126 | /* reference got in class_find_device */ | |
1e9a51dc | 1127 | return master; |
8ae12a0d DB |
1128 | } |
1129 | EXPORT_SYMBOL_GPL(spi_busnum_to_master); | |
1130 | ||
1131 | ||
1132 | /*-------------------------------------------------------------------------*/ | |
1133 | ||
7d077197 DB |
1134 | /* Core methods for SPI master protocol drivers. Some of the |
1135 | * other core methods are currently defined as inline functions. | |
1136 | */ | |
1137 | ||
1138 | /** | |
1139 | * spi_setup - setup SPI mode and clock rate | |
1140 | * @spi: the device whose settings are being modified | |
1141 | * Context: can sleep, and no requests are queued to the device | |
1142 | * | |
1143 | * SPI protocol drivers may need to update the transfer mode if the | |
1144 | * device doesn't work with its default. They may likewise need | |
1145 | * to update clock rates or word sizes from initial values. This function | |
1146 | * changes those settings, and must be called from a context that can sleep. | |
1147 | * Except for SPI_CS_HIGH, which takes effect immediately, the changes take | |
1148 | * effect the next time the device is selected and data is transferred to | |
1149 | * or from it. When this function returns, the spi device is deselected. | |
1150 | * | |
1151 | * Note that this call will fail if the protocol driver specifies an option | |
1152 | * that the underlying controller or its driver does not support. For | |
1153 | * example, not all hardware supports wire transfers using nine bit words, | |
1154 | * LSB-first wire encoding, or active-high chipselects. | |
1155 | */ | |
1156 | int spi_setup(struct spi_device *spi) | |
1157 | { | |
e7db06b5 | 1158 | unsigned bad_bits; |
7d077197 DB |
1159 | int status; |
1160 | ||
e7db06b5 DB |
1161 | /* help drivers fail *cleanly* when they need options |
1162 | * that aren't supported with their current master | |
1163 | */ | |
1164 | bad_bits = spi->mode & ~spi->master->mode_bits; | |
1165 | if (bad_bits) { | |
eb288a1f | 1166 | dev_err(&spi->dev, "setup: unsupported mode bits %x\n", |
e7db06b5 DB |
1167 | bad_bits); |
1168 | return -EINVAL; | |
1169 | } | |
1170 | ||
7d077197 DB |
1171 | if (!spi->bits_per_word) |
1172 | spi->bits_per_word = 8; | |
1173 | ||
1174 | status = spi->master->setup(spi); | |
1175 | ||
1176 | dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s" | |
1177 | "%u bits/w, %u Hz max --> %d\n", | |
1178 | (int) (spi->mode & (SPI_CPOL | SPI_CPHA)), | |
1179 | (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "", | |
1180 | (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "", | |
1181 | (spi->mode & SPI_3WIRE) ? "3wire, " : "", | |
1182 | (spi->mode & SPI_LOOP) ? "loopback, " : "", | |
1183 | spi->bits_per_word, spi->max_speed_hz, | |
1184 | status); | |
1185 | ||
1186 | return status; | |
1187 | } | |
1188 | EXPORT_SYMBOL_GPL(spi_setup); | |
1189 | ||
cf32b71e ES |
1190 | static int __spi_async(struct spi_device *spi, struct spi_message *message) |
1191 | { | |
1192 | struct spi_master *master = spi->master; | |
1193 | ||
1194 | /* Half-duplex links include original MicroWire, and ones with | |
1195 | * only one data pin like SPI_3WIRE (switches direction) or where | |
1196 | * either MOSI or MISO is missing. They can also be caused by | |
1197 | * software limitations. | |
1198 | */ | |
1199 | if ((master->flags & SPI_MASTER_HALF_DUPLEX) | |
1200 | || (spi->mode & SPI_3WIRE)) { | |
1201 | struct spi_transfer *xfer; | |
1202 | unsigned flags = master->flags; | |
1203 | ||
1204 | list_for_each_entry(xfer, &message->transfers, transfer_list) { | |
1205 | if (xfer->rx_buf && xfer->tx_buf) | |
1206 | return -EINVAL; | |
1207 | if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf) | |
1208 | return -EINVAL; | |
1209 | if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf) | |
1210 | return -EINVAL; | |
1211 | } | |
1212 | } | |
1213 | ||
1214 | message->spi = spi; | |
1215 | message->status = -EINPROGRESS; | |
1216 | return master->transfer(spi, message); | |
1217 | } | |
1218 | ||
568d0697 DB |
1219 | /** |
1220 | * spi_async - asynchronous SPI transfer | |
1221 | * @spi: device with which data will be exchanged | |
1222 | * @message: describes the data transfers, including completion callback | |
1223 | * Context: any (irqs may be blocked, etc) | |
1224 | * | |
1225 | * This call may be used in_irq and other contexts which can't sleep, | |
1226 | * as well as from task contexts which can sleep. | |
1227 | * | |
1228 | * The completion callback is invoked in a context which can't sleep. | |
1229 | * Before that invocation, the value of message->status is undefined. | |
1230 | * When the callback is issued, message->status holds either zero (to | |
1231 | * indicate complete success) or a negative error code. After that | |
1232 | * callback returns, the driver which issued the transfer request may | |
1233 | * deallocate the associated memory; it's no longer in use by any SPI | |
1234 | * core or controller driver code. | |
1235 | * | |
1236 | * Note that although all messages to a spi_device are handled in | |
1237 | * FIFO order, messages may go to different devices in other orders. | |
1238 | * Some device might be higher priority, or have various "hard" access | |
1239 | * time requirements, for example. | |
1240 | * | |
1241 | * On detection of any fault during the transfer, processing of | |
1242 | * the entire message is aborted, and the device is deselected. | |
1243 | * Until returning from the associated message completion callback, | |
1244 | * no other spi_message queued to that device will be processed. | |
1245 | * (This rule applies equally to all the synchronous transfer calls, | |
1246 | * which are wrappers around this core asynchronous primitive.) | |
1247 | */ | |
1248 | int spi_async(struct spi_device *spi, struct spi_message *message) | |
1249 | { | |
1250 | struct spi_master *master = spi->master; | |
cf32b71e ES |
1251 | int ret; |
1252 | unsigned long flags; | |
568d0697 | 1253 | |
cf32b71e | 1254 | spin_lock_irqsave(&master->bus_lock_spinlock, flags); |
568d0697 | 1255 | |
cf32b71e ES |
1256 | if (master->bus_lock_flag) |
1257 | ret = -EBUSY; | |
1258 | else | |
1259 | ret = __spi_async(spi, message); | |
568d0697 | 1260 | |
cf32b71e ES |
1261 | spin_unlock_irqrestore(&master->bus_lock_spinlock, flags); |
1262 | ||
1263 | return ret; | |
568d0697 DB |
1264 | } |
1265 | EXPORT_SYMBOL_GPL(spi_async); | |
1266 | ||
cf32b71e ES |
1267 | /** |
1268 | * spi_async_locked - version of spi_async with exclusive bus usage | |
1269 | * @spi: device with which data will be exchanged | |
1270 | * @message: describes the data transfers, including completion callback | |
1271 | * Context: any (irqs may be blocked, etc) | |
1272 | * | |
1273 | * This call may be used in_irq and other contexts which can't sleep, | |
1274 | * as well as from task contexts which can sleep. | |
1275 | * | |
1276 | * The completion callback is invoked in a context which can't sleep. | |
1277 | * Before that invocation, the value of message->status is undefined. | |
1278 | * When the callback is issued, message->status holds either zero (to | |
1279 | * indicate complete success) or a negative error code. After that | |
1280 | * callback returns, the driver which issued the transfer request may | |
1281 | * deallocate the associated memory; it's no longer in use by any SPI | |
1282 | * core or controller driver code. | |
1283 | * | |
1284 | * Note that although all messages to a spi_device are handled in | |
1285 | * FIFO order, messages may go to different devices in other orders. | |
1286 | * Some device might be higher priority, or have various "hard" access | |
1287 | * time requirements, for example. | |
1288 | * | |
1289 | * On detection of any fault during the transfer, processing of | |
1290 | * the entire message is aborted, and the device is deselected. | |
1291 | * Until returning from the associated message completion callback, | |
1292 | * no other spi_message queued to that device will be processed. | |
1293 | * (This rule applies equally to all the synchronous transfer calls, | |
1294 | * which are wrappers around this core asynchronous primitive.) | |
1295 | */ | |
1296 | int spi_async_locked(struct spi_device *spi, struct spi_message *message) | |
1297 | { | |
1298 | struct spi_master *master = spi->master; | |
1299 | int ret; | |
1300 | unsigned long flags; | |
1301 | ||
1302 | spin_lock_irqsave(&master->bus_lock_spinlock, flags); | |
1303 | ||
1304 | ret = __spi_async(spi, message); | |
1305 | ||
1306 | spin_unlock_irqrestore(&master->bus_lock_spinlock, flags); | |
1307 | ||
1308 | return ret; | |
1309 | ||
1310 | } | |
1311 | EXPORT_SYMBOL_GPL(spi_async_locked); | |
1312 | ||
7d077197 DB |
1313 | |
1314 | /*-------------------------------------------------------------------------*/ | |
1315 | ||
1316 | /* Utility methods for SPI master protocol drivers, layered on | |
1317 | * top of the core. Some other utility methods are defined as | |
1318 | * inline functions. | |
1319 | */ | |
1320 | ||
5d870c8e AM |
1321 | static void spi_complete(void *arg) |
1322 | { | |
1323 | complete(arg); | |
1324 | } | |
1325 | ||
cf32b71e ES |
1326 | static int __spi_sync(struct spi_device *spi, struct spi_message *message, |
1327 | int bus_locked) | |
1328 | { | |
1329 | DECLARE_COMPLETION_ONSTACK(done); | |
1330 | int status; | |
1331 | struct spi_master *master = spi->master; | |
1332 | ||
1333 | message->complete = spi_complete; | |
1334 | message->context = &done; | |
1335 | ||
1336 | if (!bus_locked) | |
1337 | mutex_lock(&master->bus_lock_mutex); | |
1338 | ||
1339 | status = spi_async_locked(spi, message); | |
1340 | ||
1341 | if (!bus_locked) | |
1342 | mutex_unlock(&master->bus_lock_mutex); | |
1343 | ||
1344 | if (status == 0) { | |
1345 | wait_for_completion(&done); | |
1346 | status = message->status; | |
1347 | } | |
1348 | message->context = NULL; | |
1349 | return status; | |
1350 | } | |
1351 | ||
8ae12a0d DB |
1352 | /** |
1353 | * spi_sync - blocking/synchronous SPI data transfers | |
1354 | * @spi: device with which data will be exchanged | |
1355 | * @message: describes the data transfers | |
33e34dc6 | 1356 | * Context: can sleep |
8ae12a0d DB |
1357 | * |
1358 | * This call may only be used from a context that may sleep. The sleep | |
1359 | * is non-interruptible, and has no timeout. Low-overhead controller | |
1360 | * drivers may DMA directly into and out of the message buffers. | |
1361 | * | |
1362 | * Note that the SPI device's chip select is active during the message, | |
1363 | * and then is normally disabled between messages. Drivers for some | |
1364 | * frequently-used devices may want to minimize costs of selecting a chip, | |
1365 | * by leaving it selected in anticipation that the next message will go | |
1366 | * to the same chip. (That may increase power usage.) | |
1367 | * | |
0c868461 DB |
1368 | * Also, the caller is guaranteeing that the memory associated with the |
1369 | * message will not be freed before this call returns. | |
1370 | * | |
9b938b74 | 1371 | * It returns zero on success, else a negative error code. |
8ae12a0d DB |
1372 | */ |
1373 | int spi_sync(struct spi_device *spi, struct spi_message *message) | |
1374 | { | |
cf32b71e | 1375 | return __spi_sync(spi, message, 0); |
8ae12a0d DB |
1376 | } |
1377 | EXPORT_SYMBOL_GPL(spi_sync); | |
1378 | ||
cf32b71e ES |
1379 | /** |
1380 | * spi_sync_locked - version of spi_sync with exclusive bus usage | |
1381 | * @spi: device with which data will be exchanged | |
1382 | * @message: describes the data transfers | |
1383 | * Context: can sleep | |
1384 | * | |
1385 | * This call may only be used from a context that may sleep. The sleep | |
1386 | * is non-interruptible, and has no timeout. Low-overhead controller | |
1387 | * drivers may DMA directly into and out of the message buffers. | |
1388 | * | |
1389 | * This call should be used by drivers that require exclusive access to the | |
25985edc | 1390 | * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must |
cf32b71e ES |
1391 | * be released by a spi_bus_unlock call when the exclusive access is over. |
1392 | * | |
1393 | * It returns zero on success, else a negative error code. | |
1394 | */ | |
1395 | int spi_sync_locked(struct spi_device *spi, struct spi_message *message) | |
1396 | { | |
1397 | return __spi_sync(spi, message, 1); | |
1398 | } | |
1399 | EXPORT_SYMBOL_GPL(spi_sync_locked); | |
1400 | ||
1401 | /** | |
1402 | * spi_bus_lock - obtain a lock for exclusive SPI bus usage | |
1403 | * @master: SPI bus master that should be locked for exclusive bus access | |
1404 | * Context: can sleep | |
1405 | * | |
1406 | * This call may only be used from a context that may sleep. The sleep | |
1407 | * is non-interruptible, and has no timeout. | |
1408 | * | |
1409 | * This call should be used by drivers that require exclusive access to the | |
1410 | * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the | |
1411 | * exclusive access is over. Data transfer must be done by spi_sync_locked | |
1412 | * and spi_async_locked calls when the SPI bus lock is held. | |
1413 | * | |
1414 | * It returns zero on success, else a negative error code. | |
1415 | */ | |
1416 | int spi_bus_lock(struct spi_master *master) | |
1417 | { | |
1418 | unsigned long flags; | |
1419 | ||
1420 | mutex_lock(&master->bus_lock_mutex); | |
1421 | ||
1422 | spin_lock_irqsave(&master->bus_lock_spinlock, flags); | |
1423 | master->bus_lock_flag = 1; | |
1424 | spin_unlock_irqrestore(&master->bus_lock_spinlock, flags); | |
1425 | ||
1426 | /* mutex remains locked until spi_bus_unlock is called */ | |
1427 | ||
1428 | return 0; | |
1429 | } | |
1430 | EXPORT_SYMBOL_GPL(spi_bus_lock); | |
1431 | ||
1432 | /** | |
1433 | * spi_bus_unlock - release the lock for exclusive SPI bus usage | |
1434 | * @master: SPI bus master that was locked for exclusive bus access | |
1435 | * Context: can sleep | |
1436 | * | |
1437 | * This call may only be used from a context that may sleep. The sleep | |
1438 | * is non-interruptible, and has no timeout. | |
1439 | * | |
1440 | * This call releases an SPI bus lock previously obtained by an spi_bus_lock | |
1441 | * call. | |
1442 | * | |
1443 | * It returns zero on success, else a negative error code. | |
1444 | */ | |
1445 | int spi_bus_unlock(struct spi_master *master) | |
1446 | { | |
1447 | master->bus_lock_flag = 0; | |
1448 | ||
1449 | mutex_unlock(&master->bus_lock_mutex); | |
1450 | ||
1451 | return 0; | |
1452 | } | |
1453 | EXPORT_SYMBOL_GPL(spi_bus_unlock); | |
1454 | ||
a9948b61 DB |
1455 | /* portable code must never pass more than 32 bytes */ |
1456 | #define SPI_BUFSIZ max(32,SMP_CACHE_BYTES) | |
8ae12a0d DB |
1457 | |
1458 | static u8 *buf; | |
1459 | ||
1460 | /** | |
1461 | * spi_write_then_read - SPI synchronous write followed by read | |
1462 | * @spi: device with which data will be exchanged | |
1463 | * @txbuf: data to be written (need not be dma-safe) | |
1464 | * @n_tx: size of txbuf, in bytes | |
27570497 JP |
1465 | * @rxbuf: buffer into which data will be read (need not be dma-safe) |
1466 | * @n_rx: size of rxbuf, in bytes | |
33e34dc6 | 1467 | * Context: can sleep |
8ae12a0d DB |
1468 | * |
1469 | * This performs a half duplex MicroWire style transaction with the | |
1470 | * device, sending txbuf and then reading rxbuf. The return value | |
1471 | * is zero for success, else a negative errno status code. | |
b885244e | 1472 | * This call may only be used from a context that may sleep. |
8ae12a0d | 1473 | * |
0c868461 | 1474 | * Parameters to this routine are always copied using a small buffer; |
33e34dc6 DB |
1475 | * portable code should never use this for more than 32 bytes. |
1476 | * Performance-sensitive or bulk transfer code should instead use | |
0c868461 | 1477 | * spi_{async,sync}() calls with dma-safe buffers. |
8ae12a0d DB |
1478 | */ |
1479 | int spi_write_then_read(struct spi_device *spi, | |
0c4a1590 MB |
1480 | const void *txbuf, unsigned n_tx, |
1481 | void *rxbuf, unsigned n_rx) | |
8ae12a0d | 1482 | { |
068f4070 | 1483 | static DEFINE_MUTEX(lock); |
8ae12a0d DB |
1484 | |
1485 | int status; | |
1486 | struct spi_message message; | |
bdff549e | 1487 | struct spi_transfer x[2]; |
8ae12a0d DB |
1488 | u8 *local_buf; |
1489 | ||
1490 | /* Use preallocated DMA-safe buffer. We can't avoid copying here, | |
1491 | * (as a pure convenience thing), but we can keep heap costs | |
1492 | * out of the hot path ... | |
1493 | */ | |
1494 | if ((n_tx + n_rx) > SPI_BUFSIZ) | |
1495 | return -EINVAL; | |
1496 | ||
8275c642 | 1497 | spi_message_init(&message); |
bdff549e DB |
1498 | memset(x, 0, sizeof x); |
1499 | if (n_tx) { | |
1500 | x[0].len = n_tx; | |
1501 | spi_message_add_tail(&x[0], &message); | |
1502 | } | |
1503 | if (n_rx) { | |
1504 | x[1].len = n_rx; | |
1505 | spi_message_add_tail(&x[1], &message); | |
1506 | } | |
8275c642 | 1507 | |
8ae12a0d | 1508 | /* ... unless someone else is using the pre-allocated buffer */ |
068f4070 | 1509 | if (!mutex_trylock(&lock)) { |
8ae12a0d DB |
1510 | local_buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL); |
1511 | if (!local_buf) | |
1512 | return -ENOMEM; | |
1513 | } else | |
1514 | local_buf = buf; | |
1515 | ||
8ae12a0d | 1516 | memcpy(local_buf, txbuf, n_tx); |
bdff549e DB |
1517 | x[0].tx_buf = local_buf; |
1518 | x[1].rx_buf = local_buf + n_tx; | |
8ae12a0d DB |
1519 | |
1520 | /* do the i/o */ | |
8ae12a0d | 1521 | status = spi_sync(spi, &message); |
9b938b74 | 1522 | if (status == 0) |
bdff549e | 1523 | memcpy(rxbuf, x[1].rx_buf, n_rx); |
8ae12a0d | 1524 | |
bdff549e | 1525 | if (x[0].tx_buf == buf) |
068f4070 | 1526 | mutex_unlock(&lock); |
8ae12a0d DB |
1527 | else |
1528 | kfree(local_buf); | |
1529 | ||
1530 | return status; | |
1531 | } | |
1532 | EXPORT_SYMBOL_GPL(spi_write_then_read); | |
1533 | ||
1534 | /*-------------------------------------------------------------------------*/ | |
1535 | ||
1536 | static int __init spi_init(void) | |
1537 | { | |
b885244e DB |
1538 | int status; |
1539 | ||
e94b1766 | 1540 | buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL); |
b885244e DB |
1541 | if (!buf) { |
1542 | status = -ENOMEM; | |
1543 | goto err0; | |
1544 | } | |
1545 | ||
1546 | status = bus_register(&spi_bus_type); | |
1547 | if (status < 0) | |
1548 | goto err1; | |
8ae12a0d | 1549 | |
b885244e DB |
1550 | status = class_register(&spi_master_class); |
1551 | if (status < 0) | |
1552 | goto err2; | |
8ae12a0d | 1553 | return 0; |
b885244e DB |
1554 | |
1555 | err2: | |
1556 | bus_unregister(&spi_bus_type); | |
1557 | err1: | |
1558 | kfree(buf); | |
1559 | buf = NULL; | |
1560 | err0: | |
1561 | return status; | |
8ae12a0d | 1562 | } |
b885244e | 1563 | |
8ae12a0d DB |
1564 | /* board_info is normally registered in arch_initcall(), |
1565 | * but even essential drivers wait till later | |
b885244e DB |
1566 | * |
1567 | * REVISIT only boardinfo really needs static linking. the rest (device and | |
1568 | * driver registration) _could_ be dynamically linked (modular) ... costs | |
1569 | * include needing to have boardinfo data structures be much more public. | |
8ae12a0d | 1570 | */ |
673c0c00 | 1571 | postcore_initcall(spi_init); |
8ae12a0d | 1572 |