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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> |
74317984 | 33 | #include <linux/of_gpio.h> |
3ae22e8c | 34 | #include <linux/pm_runtime.h> |
025ed130 | 35 | #include <linux/export.h> |
ffbbdd21 LW |
36 | #include <linux/sched.h> |
37 | #include <linux/delay.h> | |
38 | #include <linux/kthread.h> | |
8ae12a0d | 39 | |
8ae12a0d DB |
40 | static void spidev_release(struct device *dev) |
41 | { | |
0ffa0285 | 42 | struct spi_device *spi = to_spi_device(dev); |
8ae12a0d DB |
43 | |
44 | /* spi masters may cleanup for released devices */ | |
45 | if (spi->master->cleanup) | |
46 | spi->master->cleanup(spi); | |
47 | ||
0c868461 | 48 | spi_master_put(spi->master); |
07a389fe | 49 | kfree(spi); |
8ae12a0d DB |
50 | } |
51 | ||
52 | static ssize_t | |
53 | modalias_show(struct device *dev, struct device_attribute *a, char *buf) | |
54 | { | |
55 | const struct spi_device *spi = to_spi_device(dev); | |
56 | ||
d8e328b3 | 57 | return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias); |
8ae12a0d DB |
58 | } |
59 | ||
60 | static struct device_attribute spi_dev_attrs[] = { | |
61 | __ATTR_RO(modalias), | |
62 | __ATTR_NULL, | |
63 | }; | |
64 | ||
65 | /* modalias support makes "modprobe $MODALIAS" new-style hotplug work, | |
66 | * and the sysfs version makes coldplug work too. | |
67 | */ | |
68 | ||
75368bf6 AV |
69 | static const struct spi_device_id *spi_match_id(const struct spi_device_id *id, |
70 | const struct spi_device *sdev) | |
71 | { | |
72 | while (id->name[0]) { | |
73 | if (!strcmp(sdev->modalias, id->name)) | |
74 | return id; | |
75 | id++; | |
76 | } | |
77 | return NULL; | |
78 | } | |
79 | ||
80 | const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev) | |
81 | { | |
82 | const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver); | |
83 | ||
84 | return spi_match_id(sdrv->id_table, sdev); | |
85 | } | |
86 | EXPORT_SYMBOL_GPL(spi_get_device_id); | |
87 | ||
8ae12a0d DB |
88 | static int spi_match_device(struct device *dev, struct device_driver *drv) |
89 | { | |
90 | const struct spi_device *spi = to_spi_device(dev); | |
75368bf6 AV |
91 | const struct spi_driver *sdrv = to_spi_driver(drv); |
92 | ||
2b7a32f7 SA |
93 | /* Attempt an OF style match */ |
94 | if (of_driver_match_device(dev, drv)) | |
95 | return 1; | |
96 | ||
75368bf6 AV |
97 | if (sdrv->id_table) |
98 | return !!spi_match_id(sdrv->id_table, spi); | |
8ae12a0d | 99 | |
35f74fca | 100 | return strcmp(spi->modalias, drv->name) == 0; |
8ae12a0d DB |
101 | } |
102 | ||
7eff2e7a | 103 | static int spi_uevent(struct device *dev, struct kobj_uevent_env *env) |
8ae12a0d DB |
104 | { |
105 | const struct spi_device *spi = to_spi_device(dev); | |
106 | ||
e0626e38 | 107 | add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias); |
8ae12a0d DB |
108 | return 0; |
109 | } | |
110 | ||
3ae22e8c MB |
111 | #ifdef CONFIG_PM_SLEEP |
112 | static int spi_legacy_suspend(struct device *dev, pm_message_t message) | |
8ae12a0d | 113 | { |
3c72426f | 114 | int value = 0; |
b885244e | 115 | struct spi_driver *drv = to_spi_driver(dev->driver); |
8ae12a0d | 116 | |
8ae12a0d | 117 | /* suspend will stop irqs and dma; no more i/o */ |
3c72426f DB |
118 | if (drv) { |
119 | if (drv->suspend) | |
120 | value = drv->suspend(to_spi_device(dev), message); | |
121 | else | |
122 | dev_dbg(dev, "... can't suspend\n"); | |
123 | } | |
8ae12a0d DB |
124 | return value; |
125 | } | |
126 | ||
3ae22e8c | 127 | static int spi_legacy_resume(struct device *dev) |
8ae12a0d | 128 | { |
3c72426f | 129 | int value = 0; |
b885244e | 130 | struct spi_driver *drv = to_spi_driver(dev->driver); |
8ae12a0d | 131 | |
8ae12a0d | 132 | /* resume may restart the i/o queue */ |
3c72426f DB |
133 | if (drv) { |
134 | if (drv->resume) | |
135 | value = drv->resume(to_spi_device(dev)); | |
136 | else | |
137 | dev_dbg(dev, "... can't resume\n"); | |
138 | } | |
8ae12a0d DB |
139 | return value; |
140 | } | |
141 | ||
3ae22e8c MB |
142 | static int spi_pm_suspend(struct device *dev) |
143 | { | |
144 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
145 | ||
146 | if (pm) | |
147 | return pm_generic_suspend(dev); | |
148 | else | |
149 | return spi_legacy_suspend(dev, PMSG_SUSPEND); | |
150 | } | |
151 | ||
152 | static int spi_pm_resume(struct device *dev) | |
153 | { | |
154 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
155 | ||
156 | if (pm) | |
157 | return pm_generic_resume(dev); | |
158 | else | |
159 | return spi_legacy_resume(dev); | |
160 | } | |
161 | ||
162 | static int spi_pm_freeze(struct device *dev) | |
163 | { | |
164 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
165 | ||
166 | if (pm) | |
167 | return pm_generic_freeze(dev); | |
168 | else | |
169 | return spi_legacy_suspend(dev, PMSG_FREEZE); | |
170 | } | |
171 | ||
172 | static int spi_pm_thaw(struct device *dev) | |
173 | { | |
174 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
175 | ||
176 | if (pm) | |
177 | return pm_generic_thaw(dev); | |
178 | else | |
179 | return spi_legacy_resume(dev); | |
180 | } | |
181 | ||
182 | static int spi_pm_poweroff(struct device *dev) | |
183 | { | |
184 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
185 | ||
186 | if (pm) | |
187 | return pm_generic_poweroff(dev); | |
188 | else | |
189 | return spi_legacy_suspend(dev, PMSG_HIBERNATE); | |
190 | } | |
191 | ||
192 | static int spi_pm_restore(struct device *dev) | |
193 | { | |
194 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
195 | ||
196 | if (pm) | |
197 | return pm_generic_restore(dev); | |
198 | else | |
199 | return spi_legacy_resume(dev); | |
200 | } | |
8ae12a0d | 201 | #else |
3ae22e8c MB |
202 | #define spi_pm_suspend NULL |
203 | #define spi_pm_resume NULL | |
204 | #define spi_pm_freeze NULL | |
205 | #define spi_pm_thaw NULL | |
206 | #define spi_pm_poweroff NULL | |
207 | #define spi_pm_restore NULL | |
8ae12a0d DB |
208 | #endif |
209 | ||
3ae22e8c MB |
210 | static const struct dev_pm_ops spi_pm = { |
211 | .suspend = spi_pm_suspend, | |
212 | .resume = spi_pm_resume, | |
213 | .freeze = spi_pm_freeze, | |
214 | .thaw = spi_pm_thaw, | |
215 | .poweroff = spi_pm_poweroff, | |
216 | .restore = spi_pm_restore, | |
217 | SET_RUNTIME_PM_OPS( | |
218 | pm_generic_runtime_suspend, | |
219 | pm_generic_runtime_resume, | |
220 | pm_generic_runtime_idle | |
221 | ) | |
222 | }; | |
223 | ||
8ae12a0d DB |
224 | struct bus_type spi_bus_type = { |
225 | .name = "spi", | |
226 | .dev_attrs = spi_dev_attrs, | |
227 | .match = spi_match_device, | |
228 | .uevent = spi_uevent, | |
3ae22e8c | 229 | .pm = &spi_pm, |
8ae12a0d DB |
230 | }; |
231 | EXPORT_SYMBOL_GPL(spi_bus_type); | |
232 | ||
b885244e DB |
233 | |
234 | static int spi_drv_probe(struct device *dev) | |
235 | { | |
236 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); | |
237 | ||
238 | return sdrv->probe(to_spi_device(dev)); | |
239 | } | |
240 | ||
241 | static int spi_drv_remove(struct device *dev) | |
242 | { | |
243 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); | |
244 | ||
245 | return sdrv->remove(to_spi_device(dev)); | |
246 | } | |
247 | ||
248 | static void spi_drv_shutdown(struct device *dev) | |
249 | { | |
250 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); | |
251 | ||
252 | sdrv->shutdown(to_spi_device(dev)); | |
253 | } | |
254 | ||
33e34dc6 DB |
255 | /** |
256 | * spi_register_driver - register a SPI driver | |
257 | * @sdrv: the driver to register | |
258 | * Context: can sleep | |
259 | */ | |
b885244e DB |
260 | int spi_register_driver(struct spi_driver *sdrv) |
261 | { | |
262 | sdrv->driver.bus = &spi_bus_type; | |
263 | if (sdrv->probe) | |
264 | sdrv->driver.probe = spi_drv_probe; | |
265 | if (sdrv->remove) | |
266 | sdrv->driver.remove = spi_drv_remove; | |
267 | if (sdrv->shutdown) | |
268 | sdrv->driver.shutdown = spi_drv_shutdown; | |
269 | return driver_register(&sdrv->driver); | |
270 | } | |
271 | EXPORT_SYMBOL_GPL(spi_register_driver); | |
272 | ||
8ae12a0d DB |
273 | /*-------------------------------------------------------------------------*/ |
274 | ||
275 | /* SPI devices should normally not be created by SPI device drivers; that | |
276 | * would make them board-specific. Similarly with SPI master drivers. | |
277 | * Device registration normally goes into like arch/.../mach.../board-YYY.c | |
278 | * with other readonly (flashable) information about mainboard devices. | |
279 | */ | |
280 | ||
281 | struct boardinfo { | |
282 | struct list_head list; | |
2b9603a0 | 283 | struct spi_board_info board_info; |
8ae12a0d DB |
284 | }; |
285 | ||
286 | static LIST_HEAD(board_list); | |
2b9603a0 FT |
287 | static LIST_HEAD(spi_master_list); |
288 | ||
289 | /* | |
290 | * Used to protect add/del opertion for board_info list and | |
291 | * spi_master list, and their matching process | |
292 | */ | |
94040828 | 293 | static DEFINE_MUTEX(board_lock); |
8ae12a0d | 294 | |
dc87c98e GL |
295 | /** |
296 | * spi_alloc_device - Allocate a new SPI device | |
297 | * @master: Controller to which device is connected | |
298 | * Context: can sleep | |
299 | * | |
300 | * Allows a driver to allocate and initialize a spi_device without | |
301 | * registering it immediately. This allows a driver to directly | |
302 | * fill the spi_device with device parameters before calling | |
303 | * spi_add_device() on it. | |
304 | * | |
305 | * Caller is responsible to call spi_add_device() on the returned | |
306 | * spi_device structure to add it to the SPI master. If the caller | |
307 | * needs to discard the spi_device without adding it, then it should | |
308 | * call spi_dev_put() on it. | |
309 | * | |
310 | * Returns a pointer to the new device, or NULL. | |
311 | */ | |
312 | struct spi_device *spi_alloc_device(struct spi_master *master) | |
313 | { | |
314 | struct spi_device *spi; | |
315 | struct device *dev = master->dev.parent; | |
316 | ||
317 | if (!spi_master_get(master)) | |
318 | return NULL; | |
319 | ||
320 | spi = kzalloc(sizeof *spi, GFP_KERNEL); | |
321 | if (!spi) { | |
322 | dev_err(dev, "cannot alloc spi_device\n"); | |
323 | spi_master_put(master); | |
324 | return NULL; | |
325 | } | |
326 | ||
327 | spi->master = master; | |
178db7d3 | 328 | spi->dev.parent = &master->dev; |
dc87c98e GL |
329 | spi->dev.bus = &spi_bus_type; |
330 | spi->dev.release = spidev_release; | |
74317984 | 331 | spi->cs_gpio = -EINVAL; |
dc87c98e GL |
332 | device_initialize(&spi->dev); |
333 | return spi; | |
334 | } | |
335 | EXPORT_SYMBOL_GPL(spi_alloc_device); | |
336 | ||
337 | /** | |
338 | * spi_add_device - Add spi_device allocated with spi_alloc_device | |
339 | * @spi: spi_device to register | |
340 | * | |
341 | * Companion function to spi_alloc_device. Devices allocated with | |
342 | * spi_alloc_device can be added onto the spi bus with this function. | |
343 | * | |
e48880e0 | 344 | * Returns 0 on success; negative errno on failure |
dc87c98e GL |
345 | */ |
346 | int spi_add_device(struct spi_device *spi) | |
347 | { | |
e48880e0 | 348 | static DEFINE_MUTEX(spi_add_lock); |
74317984 JCPV |
349 | struct spi_master *master = spi->master; |
350 | struct device *dev = master->dev.parent; | |
8ec130a0 | 351 | struct device *d; |
dc87c98e GL |
352 | int status; |
353 | ||
354 | /* Chipselects are numbered 0..max; validate. */ | |
74317984 | 355 | if (spi->chip_select >= master->num_chipselect) { |
dc87c98e GL |
356 | dev_err(dev, "cs%d >= max %d\n", |
357 | spi->chip_select, | |
74317984 | 358 | master->num_chipselect); |
dc87c98e GL |
359 | return -EINVAL; |
360 | } | |
361 | ||
362 | /* Set the bus ID string */ | |
35f74fca | 363 | dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev), |
dc87c98e GL |
364 | spi->chip_select); |
365 | ||
e48880e0 DB |
366 | |
367 | /* We need to make sure there's no other device with this | |
368 | * chipselect **BEFORE** we call setup(), else we'll trash | |
369 | * its configuration. Lock against concurrent add() calls. | |
370 | */ | |
371 | mutex_lock(&spi_add_lock); | |
372 | ||
8ec130a0 RT |
373 | d = bus_find_device_by_name(&spi_bus_type, NULL, dev_name(&spi->dev)); |
374 | if (d != NULL) { | |
e48880e0 DB |
375 | dev_err(dev, "chipselect %d already in use\n", |
376 | spi->chip_select); | |
8ec130a0 | 377 | put_device(d); |
e48880e0 DB |
378 | status = -EBUSY; |
379 | goto done; | |
380 | } | |
381 | ||
74317984 JCPV |
382 | if (master->cs_gpios) |
383 | spi->cs_gpio = master->cs_gpios[spi->chip_select]; | |
384 | ||
e48880e0 DB |
385 | /* Drivers may modify this initial i/o setup, but will |
386 | * normally rely on the device being setup. Devices | |
387 | * using SPI_CS_HIGH can't coexist well otherwise... | |
388 | */ | |
7d077197 | 389 | status = spi_setup(spi); |
dc87c98e | 390 | if (status < 0) { |
eb288a1f LW |
391 | dev_err(dev, "can't setup %s, status %d\n", |
392 | dev_name(&spi->dev), status); | |
e48880e0 | 393 | goto done; |
dc87c98e GL |
394 | } |
395 | ||
e48880e0 | 396 | /* Device may be bound to an active driver when this returns */ |
dc87c98e | 397 | status = device_add(&spi->dev); |
e48880e0 | 398 | if (status < 0) |
eb288a1f LW |
399 | dev_err(dev, "can't add %s, status %d\n", |
400 | dev_name(&spi->dev), status); | |
e48880e0 | 401 | else |
35f74fca | 402 | dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev)); |
dc87c98e | 403 | |
e48880e0 DB |
404 | done: |
405 | mutex_unlock(&spi_add_lock); | |
406 | return status; | |
dc87c98e GL |
407 | } |
408 | EXPORT_SYMBOL_GPL(spi_add_device); | |
8ae12a0d | 409 | |
33e34dc6 DB |
410 | /** |
411 | * spi_new_device - instantiate one new SPI device | |
412 | * @master: Controller to which device is connected | |
413 | * @chip: Describes the SPI device | |
414 | * Context: can sleep | |
415 | * | |
416 | * On typical mainboards, this is purely internal; and it's not needed | |
8ae12a0d DB |
417 | * after board init creates the hard-wired devices. Some development |
418 | * platforms may not be able to use spi_register_board_info though, and | |
419 | * this is exported so that for example a USB or parport based adapter | |
420 | * driver could add devices (which it would learn about out-of-band). | |
082c8cb4 DB |
421 | * |
422 | * Returns the new device, or NULL. | |
8ae12a0d | 423 | */ |
e9d5a461 AB |
424 | struct spi_device *spi_new_device(struct spi_master *master, |
425 | struct spi_board_info *chip) | |
8ae12a0d DB |
426 | { |
427 | struct spi_device *proxy; | |
8ae12a0d DB |
428 | int status; |
429 | ||
082c8cb4 DB |
430 | /* NOTE: caller did any chip->bus_num checks necessary. |
431 | * | |
432 | * Also, unless we change the return value convention to use | |
433 | * error-or-pointer (not NULL-or-pointer), troubleshootability | |
434 | * suggests syslogged diagnostics are best here (ugh). | |
435 | */ | |
436 | ||
dc87c98e GL |
437 | proxy = spi_alloc_device(master); |
438 | if (!proxy) | |
8ae12a0d DB |
439 | return NULL; |
440 | ||
102eb975 GL |
441 | WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias)); |
442 | ||
8ae12a0d DB |
443 | proxy->chip_select = chip->chip_select; |
444 | proxy->max_speed_hz = chip->max_speed_hz; | |
980a01c9 | 445 | proxy->mode = chip->mode; |
8ae12a0d | 446 | proxy->irq = chip->irq; |
102eb975 | 447 | strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias)); |
8ae12a0d DB |
448 | proxy->dev.platform_data = (void *) chip->platform_data; |
449 | proxy->controller_data = chip->controller_data; | |
450 | proxy->controller_state = NULL; | |
8ae12a0d | 451 | |
dc87c98e | 452 | status = spi_add_device(proxy); |
8ae12a0d | 453 | if (status < 0) { |
dc87c98e GL |
454 | spi_dev_put(proxy); |
455 | return NULL; | |
8ae12a0d DB |
456 | } |
457 | ||
8ae12a0d DB |
458 | return proxy; |
459 | } | |
460 | EXPORT_SYMBOL_GPL(spi_new_device); | |
461 | ||
2b9603a0 FT |
462 | static void spi_match_master_to_boardinfo(struct spi_master *master, |
463 | struct spi_board_info *bi) | |
464 | { | |
465 | struct spi_device *dev; | |
466 | ||
467 | if (master->bus_num != bi->bus_num) | |
468 | return; | |
469 | ||
470 | dev = spi_new_device(master, bi); | |
471 | if (!dev) | |
472 | dev_err(master->dev.parent, "can't create new device for %s\n", | |
473 | bi->modalias); | |
474 | } | |
475 | ||
33e34dc6 DB |
476 | /** |
477 | * spi_register_board_info - register SPI devices for a given board | |
478 | * @info: array of chip descriptors | |
479 | * @n: how many descriptors are provided | |
480 | * Context: can sleep | |
481 | * | |
8ae12a0d DB |
482 | * Board-specific early init code calls this (probably during arch_initcall) |
483 | * with segments of the SPI device table. Any device nodes are created later, | |
484 | * after the relevant parent SPI controller (bus_num) is defined. We keep | |
485 | * this table of devices forever, so that reloading a controller driver will | |
486 | * not make Linux forget about these hard-wired devices. | |
487 | * | |
488 | * Other code can also call this, e.g. a particular add-on board might provide | |
489 | * SPI devices through its expansion connector, so code initializing that board | |
490 | * would naturally declare its SPI devices. | |
491 | * | |
492 | * The board info passed can safely be __initdata ... but be careful of | |
493 | * any embedded pointers (platform_data, etc), they're copied as-is. | |
494 | */ | |
690fb11b | 495 | int __devinit |
8ae12a0d DB |
496 | spi_register_board_info(struct spi_board_info const *info, unsigned n) |
497 | { | |
2b9603a0 FT |
498 | struct boardinfo *bi; |
499 | int i; | |
8ae12a0d | 500 | |
2b9603a0 | 501 | bi = kzalloc(n * sizeof(*bi), GFP_KERNEL); |
8ae12a0d DB |
502 | if (!bi) |
503 | return -ENOMEM; | |
8ae12a0d | 504 | |
2b9603a0 FT |
505 | for (i = 0; i < n; i++, bi++, info++) { |
506 | struct spi_master *master; | |
8ae12a0d | 507 | |
2b9603a0 FT |
508 | memcpy(&bi->board_info, info, sizeof(*info)); |
509 | mutex_lock(&board_lock); | |
510 | list_add_tail(&bi->list, &board_list); | |
511 | list_for_each_entry(master, &spi_master_list, list) | |
512 | spi_match_master_to_boardinfo(master, &bi->board_info); | |
513 | mutex_unlock(&board_lock); | |
8ae12a0d | 514 | } |
2b9603a0 FT |
515 | |
516 | return 0; | |
8ae12a0d DB |
517 | } |
518 | ||
519 | /*-------------------------------------------------------------------------*/ | |
520 | ||
ffbbdd21 LW |
521 | /** |
522 | * spi_pump_messages - kthread work function which processes spi message queue | |
523 | * @work: pointer to kthread work struct contained in the master struct | |
524 | * | |
525 | * This function checks if there is any spi message in the queue that | |
526 | * needs processing and if so call out to the driver to initialize hardware | |
527 | * and transfer each message. | |
528 | * | |
529 | */ | |
530 | static void spi_pump_messages(struct kthread_work *work) | |
531 | { | |
532 | struct spi_master *master = | |
533 | container_of(work, struct spi_master, pump_messages); | |
534 | unsigned long flags; | |
535 | bool was_busy = false; | |
536 | int ret; | |
537 | ||
538 | /* Lock queue and check for queue work */ | |
539 | spin_lock_irqsave(&master->queue_lock, flags); | |
540 | if (list_empty(&master->queue) || !master->running) { | |
7dfd2bd7 | 541 | if (master->busy && master->unprepare_transfer_hardware) { |
ffbbdd21 LW |
542 | ret = master->unprepare_transfer_hardware(master); |
543 | if (ret) { | |
9af4acc0 | 544 | spin_unlock_irqrestore(&master->queue_lock, flags); |
ffbbdd21 LW |
545 | dev_err(&master->dev, |
546 | "failed to unprepare transfer hardware\n"); | |
547 | return; | |
548 | } | |
549 | } | |
550 | master->busy = false; | |
551 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
552 | return; | |
553 | } | |
554 | ||
555 | /* Make sure we are not already running a message */ | |
556 | if (master->cur_msg) { | |
557 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
558 | return; | |
559 | } | |
560 | /* Extract head of queue */ | |
561 | master->cur_msg = | |
562 | list_entry(master->queue.next, struct spi_message, queue); | |
563 | ||
564 | list_del_init(&master->cur_msg->queue); | |
565 | if (master->busy) | |
566 | was_busy = true; | |
567 | else | |
568 | master->busy = true; | |
569 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
570 | ||
7dfd2bd7 | 571 | if (!was_busy && master->prepare_transfer_hardware) { |
ffbbdd21 LW |
572 | ret = master->prepare_transfer_hardware(master); |
573 | if (ret) { | |
574 | dev_err(&master->dev, | |
575 | "failed to prepare transfer hardware\n"); | |
576 | return; | |
577 | } | |
578 | } | |
579 | ||
580 | ret = master->transfer_one_message(master, master->cur_msg); | |
581 | if (ret) { | |
582 | dev_err(&master->dev, | |
583 | "failed to transfer one message from queue\n"); | |
584 | return; | |
585 | } | |
586 | } | |
587 | ||
588 | static int spi_init_queue(struct spi_master *master) | |
589 | { | |
590 | struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 }; | |
591 | ||
592 | INIT_LIST_HEAD(&master->queue); | |
593 | spin_lock_init(&master->queue_lock); | |
594 | ||
595 | master->running = false; | |
596 | master->busy = false; | |
597 | ||
598 | init_kthread_worker(&master->kworker); | |
599 | master->kworker_task = kthread_run(kthread_worker_fn, | |
600 | &master->kworker, | |
601 | dev_name(&master->dev)); | |
602 | if (IS_ERR(master->kworker_task)) { | |
603 | dev_err(&master->dev, "failed to create message pump task\n"); | |
604 | return -ENOMEM; | |
605 | } | |
606 | init_kthread_work(&master->pump_messages, spi_pump_messages); | |
607 | ||
608 | /* | |
609 | * Master config will indicate if this controller should run the | |
610 | * message pump with high (realtime) priority to reduce the transfer | |
611 | * latency on the bus by minimising the delay between a transfer | |
612 | * request and the scheduling of the message pump thread. Without this | |
613 | * setting the message pump thread will remain at default priority. | |
614 | */ | |
615 | if (master->rt) { | |
616 | dev_info(&master->dev, | |
617 | "will run message pump with realtime priority\n"); | |
618 | sched_setscheduler(master->kworker_task, SCHED_FIFO, ¶m); | |
619 | } | |
620 | ||
621 | return 0; | |
622 | } | |
623 | ||
624 | /** | |
625 | * spi_get_next_queued_message() - called by driver to check for queued | |
626 | * messages | |
627 | * @master: the master to check for queued messages | |
628 | * | |
629 | * If there are more messages in the queue, the next message is returned from | |
630 | * this call. | |
631 | */ | |
632 | struct spi_message *spi_get_next_queued_message(struct spi_master *master) | |
633 | { | |
634 | struct spi_message *next; | |
635 | unsigned long flags; | |
636 | ||
637 | /* get a pointer to the next message, if any */ | |
638 | spin_lock_irqsave(&master->queue_lock, flags); | |
639 | if (list_empty(&master->queue)) | |
640 | next = NULL; | |
641 | else | |
642 | next = list_entry(master->queue.next, | |
643 | struct spi_message, queue); | |
644 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
645 | ||
646 | return next; | |
647 | } | |
648 | EXPORT_SYMBOL_GPL(spi_get_next_queued_message); | |
649 | ||
650 | /** | |
651 | * spi_finalize_current_message() - the current message is complete | |
652 | * @master: the master to return the message to | |
653 | * | |
654 | * Called by the driver to notify the core that the message in the front of the | |
655 | * queue is complete and can be removed from the queue. | |
656 | */ | |
657 | void spi_finalize_current_message(struct spi_master *master) | |
658 | { | |
659 | struct spi_message *mesg; | |
660 | unsigned long flags; | |
661 | ||
662 | spin_lock_irqsave(&master->queue_lock, flags); | |
663 | mesg = master->cur_msg; | |
664 | master->cur_msg = NULL; | |
665 | ||
666 | queue_kthread_work(&master->kworker, &master->pump_messages); | |
667 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
668 | ||
669 | mesg->state = NULL; | |
670 | if (mesg->complete) | |
671 | mesg->complete(mesg->context); | |
672 | } | |
673 | EXPORT_SYMBOL_GPL(spi_finalize_current_message); | |
674 | ||
675 | static int spi_start_queue(struct spi_master *master) | |
676 | { | |
677 | unsigned long flags; | |
678 | ||
679 | spin_lock_irqsave(&master->queue_lock, flags); | |
680 | ||
681 | if (master->running || master->busy) { | |
682 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
683 | return -EBUSY; | |
684 | } | |
685 | ||
686 | master->running = true; | |
687 | master->cur_msg = NULL; | |
688 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
689 | ||
690 | queue_kthread_work(&master->kworker, &master->pump_messages); | |
691 | ||
692 | return 0; | |
693 | } | |
694 | ||
695 | static int spi_stop_queue(struct spi_master *master) | |
696 | { | |
697 | unsigned long flags; | |
698 | unsigned limit = 500; | |
699 | int ret = 0; | |
700 | ||
701 | spin_lock_irqsave(&master->queue_lock, flags); | |
702 | ||
703 | /* | |
704 | * This is a bit lame, but is optimized for the common execution path. | |
705 | * A wait_queue on the master->busy could be used, but then the common | |
706 | * execution path (pump_messages) would be required to call wake_up or | |
707 | * friends on every SPI message. Do this instead. | |
708 | */ | |
709 | while ((!list_empty(&master->queue) || master->busy) && limit--) { | |
710 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
711 | msleep(10); | |
712 | spin_lock_irqsave(&master->queue_lock, flags); | |
713 | } | |
714 | ||
715 | if (!list_empty(&master->queue) || master->busy) | |
716 | ret = -EBUSY; | |
717 | else | |
718 | master->running = false; | |
719 | ||
720 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
721 | ||
722 | if (ret) { | |
723 | dev_warn(&master->dev, | |
724 | "could not stop message queue\n"); | |
725 | return ret; | |
726 | } | |
727 | return ret; | |
728 | } | |
729 | ||
730 | static int spi_destroy_queue(struct spi_master *master) | |
731 | { | |
732 | int ret; | |
733 | ||
734 | ret = spi_stop_queue(master); | |
735 | ||
736 | /* | |
737 | * flush_kthread_worker will block until all work is done. | |
738 | * If the reason that stop_queue timed out is that the work will never | |
739 | * finish, then it does no good to call flush/stop thread, so | |
740 | * return anyway. | |
741 | */ | |
742 | if (ret) { | |
743 | dev_err(&master->dev, "problem destroying queue\n"); | |
744 | return ret; | |
745 | } | |
746 | ||
747 | flush_kthread_worker(&master->kworker); | |
748 | kthread_stop(master->kworker_task); | |
749 | ||
750 | return 0; | |
751 | } | |
752 | ||
753 | /** | |
754 | * spi_queued_transfer - transfer function for queued transfers | |
755 | * @spi: spi device which is requesting transfer | |
756 | * @msg: spi message which is to handled is queued to driver queue | |
757 | */ | |
758 | static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg) | |
759 | { | |
760 | struct spi_master *master = spi->master; | |
761 | unsigned long flags; | |
762 | ||
763 | spin_lock_irqsave(&master->queue_lock, flags); | |
764 | ||
765 | if (!master->running) { | |
766 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
767 | return -ESHUTDOWN; | |
768 | } | |
769 | msg->actual_length = 0; | |
770 | msg->status = -EINPROGRESS; | |
771 | ||
772 | list_add_tail(&msg->queue, &master->queue); | |
773 | if (master->running && !master->busy) | |
774 | queue_kthread_work(&master->kworker, &master->pump_messages); | |
775 | ||
776 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
777 | return 0; | |
778 | } | |
779 | ||
780 | static int spi_master_initialize_queue(struct spi_master *master) | |
781 | { | |
782 | int ret; | |
783 | ||
784 | master->queued = true; | |
785 | master->transfer = spi_queued_transfer; | |
786 | ||
787 | /* Initialize and start queue */ | |
788 | ret = spi_init_queue(master); | |
789 | if (ret) { | |
790 | dev_err(&master->dev, "problem initializing queue\n"); | |
791 | goto err_init_queue; | |
792 | } | |
793 | ret = spi_start_queue(master); | |
794 | if (ret) { | |
795 | dev_err(&master->dev, "problem starting queue\n"); | |
796 | goto err_start_queue; | |
797 | } | |
798 | ||
799 | return 0; | |
800 | ||
801 | err_start_queue: | |
802 | err_init_queue: | |
803 | spi_destroy_queue(master); | |
804 | return ret; | |
805 | } | |
806 | ||
807 | /*-------------------------------------------------------------------------*/ | |
808 | ||
d57a4282 GL |
809 | #if defined(CONFIG_OF) && !defined(CONFIG_SPARC) |
810 | /** | |
811 | * of_register_spi_devices() - Register child devices onto the SPI bus | |
812 | * @master: Pointer to spi_master device | |
813 | * | |
814 | * Registers an spi_device for each child node of master node which has a 'reg' | |
815 | * property. | |
816 | */ | |
817 | static void of_register_spi_devices(struct spi_master *master) | |
818 | { | |
819 | struct spi_device *spi; | |
820 | struct device_node *nc; | |
821 | const __be32 *prop; | |
822 | int rc; | |
823 | int len; | |
824 | ||
825 | if (!master->dev.of_node) | |
826 | return; | |
827 | ||
828 | for_each_child_of_node(master->dev.of_node, nc) { | |
829 | /* Alloc an spi_device */ | |
830 | spi = spi_alloc_device(master); | |
831 | if (!spi) { | |
832 | dev_err(&master->dev, "spi_device alloc error for %s\n", | |
833 | nc->full_name); | |
834 | spi_dev_put(spi); | |
835 | continue; | |
836 | } | |
837 | ||
838 | /* Select device driver */ | |
839 | if (of_modalias_node(nc, spi->modalias, | |
840 | sizeof(spi->modalias)) < 0) { | |
841 | dev_err(&master->dev, "cannot find modalias for %s\n", | |
842 | nc->full_name); | |
843 | spi_dev_put(spi); | |
844 | continue; | |
845 | } | |
846 | ||
847 | /* Device address */ | |
848 | prop = of_get_property(nc, "reg", &len); | |
849 | if (!prop || len < sizeof(*prop)) { | |
850 | dev_err(&master->dev, "%s has no 'reg' property\n", | |
851 | nc->full_name); | |
852 | spi_dev_put(spi); | |
853 | continue; | |
854 | } | |
855 | spi->chip_select = be32_to_cpup(prop); | |
856 | ||
857 | /* Mode (clock phase/polarity/etc.) */ | |
858 | if (of_find_property(nc, "spi-cpha", NULL)) | |
859 | spi->mode |= SPI_CPHA; | |
860 | if (of_find_property(nc, "spi-cpol", NULL)) | |
861 | spi->mode |= SPI_CPOL; | |
862 | if (of_find_property(nc, "spi-cs-high", NULL)) | |
863 | spi->mode |= SPI_CS_HIGH; | |
864 | ||
865 | /* Device speed */ | |
866 | prop = of_get_property(nc, "spi-max-frequency", &len); | |
867 | if (!prop || len < sizeof(*prop)) { | |
868 | dev_err(&master->dev, "%s has no 'spi-max-frequency' property\n", | |
869 | nc->full_name); | |
870 | spi_dev_put(spi); | |
871 | continue; | |
872 | } | |
873 | spi->max_speed_hz = be32_to_cpup(prop); | |
874 | ||
875 | /* IRQ */ | |
876 | spi->irq = irq_of_parse_and_map(nc, 0); | |
877 | ||
878 | /* Store a pointer to the node in the device structure */ | |
879 | of_node_get(nc); | |
880 | spi->dev.of_node = nc; | |
881 | ||
882 | /* Register the new device */ | |
883 | request_module(spi->modalias); | |
884 | rc = spi_add_device(spi); | |
885 | if (rc) { | |
886 | dev_err(&master->dev, "spi_device register error %s\n", | |
887 | nc->full_name); | |
888 | spi_dev_put(spi); | |
889 | } | |
890 | ||
891 | } | |
892 | } | |
893 | #else | |
894 | static void of_register_spi_devices(struct spi_master *master) { } | |
895 | #endif | |
896 | ||
49dce689 | 897 | static void spi_master_release(struct device *dev) |
8ae12a0d DB |
898 | { |
899 | struct spi_master *master; | |
900 | ||
49dce689 | 901 | master = container_of(dev, struct spi_master, dev); |
8ae12a0d DB |
902 | kfree(master); |
903 | } | |
904 | ||
905 | static struct class spi_master_class = { | |
906 | .name = "spi_master", | |
907 | .owner = THIS_MODULE, | |
49dce689 | 908 | .dev_release = spi_master_release, |
8ae12a0d DB |
909 | }; |
910 | ||
911 | ||
ffbbdd21 | 912 | |
8ae12a0d DB |
913 | /** |
914 | * spi_alloc_master - allocate SPI master controller | |
915 | * @dev: the controller, possibly using the platform_bus | |
33e34dc6 | 916 | * @size: how much zeroed driver-private data to allocate; the pointer to this |
49dce689 | 917 | * memory is in the driver_data field of the returned device, |
0c868461 | 918 | * accessible with spi_master_get_devdata(). |
33e34dc6 | 919 | * Context: can sleep |
8ae12a0d DB |
920 | * |
921 | * This call is used only by SPI master controller drivers, which are the | |
922 | * only ones directly touching chip registers. It's how they allocate | |
ba1a0513 | 923 | * an spi_master structure, prior to calling spi_register_master(). |
8ae12a0d DB |
924 | * |
925 | * This must be called from context that can sleep. It returns the SPI | |
926 | * master structure on success, else NULL. | |
927 | * | |
928 | * The caller is responsible for assigning the bus number and initializing | |
ba1a0513 | 929 | * the master's methods before calling spi_register_master(); and (after errors |
eb4af0f5 UKK |
930 | * adding the device) calling spi_master_put() and kfree() to prevent a memory |
931 | * leak. | |
8ae12a0d | 932 | */ |
e9d5a461 | 933 | struct spi_master *spi_alloc_master(struct device *dev, unsigned size) |
8ae12a0d DB |
934 | { |
935 | struct spi_master *master; | |
936 | ||
0c868461 DB |
937 | if (!dev) |
938 | return NULL; | |
939 | ||
e94b1766 | 940 | master = kzalloc(size + sizeof *master, GFP_KERNEL); |
8ae12a0d DB |
941 | if (!master) |
942 | return NULL; | |
943 | ||
49dce689 | 944 | device_initialize(&master->dev); |
1e8a52e1 GL |
945 | master->bus_num = -1; |
946 | master->num_chipselect = 1; | |
49dce689 TJ |
947 | master->dev.class = &spi_master_class; |
948 | master->dev.parent = get_device(dev); | |
0c868461 | 949 | spi_master_set_devdata(master, &master[1]); |
8ae12a0d DB |
950 | |
951 | return master; | |
952 | } | |
953 | EXPORT_SYMBOL_GPL(spi_alloc_master); | |
954 | ||
74317984 JCPV |
955 | #ifdef CONFIG_OF |
956 | static int of_spi_register_master(struct spi_master *master) | |
957 | { | |
958 | u16 nb; | |
959 | int i, *cs; | |
960 | struct device_node *np = master->dev.of_node; | |
961 | ||
962 | if (!np) | |
963 | return 0; | |
964 | ||
965 | nb = of_gpio_named_count(np, "cs-gpios"); | |
966 | master->num_chipselect = max(nb, master->num_chipselect); | |
967 | ||
968 | if (nb < 1) | |
969 | return 0; | |
970 | ||
971 | cs = devm_kzalloc(&master->dev, | |
972 | sizeof(int) * master->num_chipselect, | |
973 | GFP_KERNEL); | |
974 | master->cs_gpios = cs; | |
975 | ||
976 | if (!master->cs_gpios) | |
977 | return -ENOMEM; | |
978 | ||
979 | memset(cs, -EINVAL, master->num_chipselect); | |
980 | ||
981 | for (i = 0; i < nb; i++) | |
982 | cs[i] = of_get_named_gpio(np, "cs-gpios", i); | |
983 | ||
984 | return 0; | |
985 | } | |
986 | #else | |
987 | static int of_spi_register_master(struct spi_master *master) | |
988 | { | |
989 | return 0; | |
990 | } | |
991 | #endif | |
992 | ||
8ae12a0d DB |
993 | /** |
994 | * spi_register_master - register SPI master controller | |
995 | * @master: initialized master, originally from spi_alloc_master() | |
33e34dc6 | 996 | * Context: can sleep |
8ae12a0d DB |
997 | * |
998 | * SPI master controllers connect to their drivers using some non-SPI bus, | |
999 | * such as the platform bus. The final stage of probe() in that code | |
1000 | * includes calling spi_register_master() to hook up to this SPI bus glue. | |
1001 | * | |
1002 | * SPI controllers use board specific (often SOC specific) bus numbers, | |
1003 | * and board-specific addressing for SPI devices combines those numbers | |
1004 | * with chip select numbers. Since SPI does not directly support dynamic | |
1005 | * device identification, boards need configuration tables telling which | |
1006 | * chip is at which address. | |
1007 | * | |
1008 | * This must be called from context that can sleep. It returns zero on | |
1009 | * success, else a negative error code (dropping the master's refcount). | |
0c868461 DB |
1010 | * After a successful return, the caller is responsible for calling |
1011 | * spi_unregister_master(). | |
8ae12a0d | 1012 | */ |
e9d5a461 | 1013 | int spi_register_master(struct spi_master *master) |
8ae12a0d | 1014 | { |
e44a45ae | 1015 | static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1); |
49dce689 | 1016 | struct device *dev = master->dev.parent; |
2b9603a0 | 1017 | struct boardinfo *bi; |
8ae12a0d DB |
1018 | int status = -ENODEV; |
1019 | int dynamic = 0; | |
1020 | ||
0c868461 DB |
1021 | if (!dev) |
1022 | return -ENODEV; | |
1023 | ||
74317984 JCPV |
1024 | status = of_spi_register_master(master); |
1025 | if (status) | |
1026 | return status; | |
1027 | ||
082c8cb4 DB |
1028 | /* even if it's just one always-selected device, there must |
1029 | * be at least one chipselect | |
1030 | */ | |
1031 | if (master->num_chipselect == 0) | |
1032 | return -EINVAL; | |
1033 | ||
8ae12a0d | 1034 | /* convention: dynamically assigned bus IDs count down from the max */ |
a020ed75 | 1035 | if (master->bus_num < 0) { |
082c8cb4 DB |
1036 | /* FIXME switch to an IDR based scheme, something like |
1037 | * I2C now uses, so we can't run out of "dynamic" IDs | |
1038 | */ | |
8ae12a0d | 1039 | master->bus_num = atomic_dec_return(&dyn_bus_id); |
b885244e | 1040 | dynamic = 1; |
8ae12a0d DB |
1041 | } |
1042 | ||
cf32b71e ES |
1043 | spin_lock_init(&master->bus_lock_spinlock); |
1044 | mutex_init(&master->bus_lock_mutex); | |
1045 | master->bus_lock_flag = 0; | |
1046 | ||
8ae12a0d DB |
1047 | /* register the device, then userspace will see it. |
1048 | * registration fails if the bus ID is in use. | |
1049 | */ | |
35f74fca | 1050 | dev_set_name(&master->dev, "spi%u", master->bus_num); |
49dce689 | 1051 | status = device_add(&master->dev); |
b885244e | 1052 | if (status < 0) |
8ae12a0d | 1053 | goto done; |
35f74fca | 1054 | dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev), |
8ae12a0d DB |
1055 | dynamic ? " (dynamic)" : ""); |
1056 | ||
ffbbdd21 LW |
1057 | /* If we're using a queued driver, start the queue */ |
1058 | if (master->transfer) | |
1059 | dev_info(dev, "master is unqueued, this is deprecated\n"); | |
1060 | else { | |
1061 | status = spi_master_initialize_queue(master); | |
1062 | if (status) { | |
1063 | device_unregister(&master->dev); | |
1064 | goto done; | |
1065 | } | |
1066 | } | |
1067 | ||
2b9603a0 FT |
1068 | mutex_lock(&board_lock); |
1069 | list_add_tail(&master->list, &spi_master_list); | |
1070 | list_for_each_entry(bi, &board_list, list) | |
1071 | spi_match_master_to_boardinfo(master, &bi->board_info); | |
1072 | mutex_unlock(&board_lock); | |
1073 | ||
12b15e83 AG |
1074 | /* Register devices from the device tree */ |
1075 | of_register_spi_devices(master); | |
8ae12a0d DB |
1076 | done: |
1077 | return status; | |
1078 | } | |
1079 | EXPORT_SYMBOL_GPL(spi_register_master); | |
1080 | ||
34860089 | 1081 | static int __unregister(struct device *dev, void *null) |
8ae12a0d | 1082 | { |
34860089 | 1083 | spi_unregister_device(to_spi_device(dev)); |
8ae12a0d DB |
1084 | return 0; |
1085 | } | |
1086 | ||
1087 | /** | |
1088 | * spi_unregister_master - unregister SPI master controller | |
1089 | * @master: the master being unregistered | |
33e34dc6 | 1090 | * Context: can sleep |
8ae12a0d DB |
1091 | * |
1092 | * This call is used only by SPI master controller drivers, which are the | |
1093 | * only ones directly touching chip registers. | |
1094 | * | |
1095 | * This must be called from context that can sleep. | |
1096 | */ | |
1097 | void spi_unregister_master(struct spi_master *master) | |
1098 | { | |
89fc9a1a JG |
1099 | int dummy; |
1100 | ||
ffbbdd21 LW |
1101 | if (master->queued) { |
1102 | if (spi_destroy_queue(master)) | |
1103 | dev_err(&master->dev, "queue remove failed\n"); | |
1104 | } | |
1105 | ||
2b9603a0 FT |
1106 | mutex_lock(&board_lock); |
1107 | list_del(&master->list); | |
1108 | mutex_unlock(&board_lock); | |
1109 | ||
97dbf37d | 1110 | dummy = device_for_each_child(&master->dev, NULL, __unregister); |
49dce689 | 1111 | device_unregister(&master->dev); |
8ae12a0d DB |
1112 | } |
1113 | EXPORT_SYMBOL_GPL(spi_unregister_master); | |
1114 | ||
ffbbdd21 LW |
1115 | int spi_master_suspend(struct spi_master *master) |
1116 | { | |
1117 | int ret; | |
1118 | ||
1119 | /* Basically no-ops for non-queued masters */ | |
1120 | if (!master->queued) | |
1121 | return 0; | |
1122 | ||
1123 | ret = spi_stop_queue(master); | |
1124 | if (ret) | |
1125 | dev_err(&master->dev, "queue stop failed\n"); | |
1126 | ||
1127 | return ret; | |
1128 | } | |
1129 | EXPORT_SYMBOL_GPL(spi_master_suspend); | |
1130 | ||
1131 | int spi_master_resume(struct spi_master *master) | |
1132 | { | |
1133 | int ret; | |
1134 | ||
1135 | if (!master->queued) | |
1136 | return 0; | |
1137 | ||
1138 | ret = spi_start_queue(master); | |
1139 | if (ret) | |
1140 | dev_err(&master->dev, "queue restart failed\n"); | |
1141 | ||
1142 | return ret; | |
1143 | } | |
1144 | EXPORT_SYMBOL_GPL(spi_master_resume); | |
1145 | ||
5ed2c832 DY |
1146 | static int __spi_master_match(struct device *dev, void *data) |
1147 | { | |
1148 | struct spi_master *m; | |
1149 | u16 *bus_num = data; | |
1150 | ||
1151 | m = container_of(dev, struct spi_master, dev); | |
1152 | return m->bus_num == *bus_num; | |
1153 | } | |
1154 | ||
8ae12a0d DB |
1155 | /** |
1156 | * spi_busnum_to_master - look up master associated with bus_num | |
1157 | * @bus_num: the master's bus number | |
33e34dc6 | 1158 | * Context: can sleep |
8ae12a0d DB |
1159 | * |
1160 | * This call may be used with devices that are registered after | |
1161 | * arch init time. It returns a refcounted pointer to the relevant | |
1162 | * spi_master (which the caller must release), or NULL if there is | |
1163 | * no such master registered. | |
1164 | */ | |
1165 | struct spi_master *spi_busnum_to_master(u16 bus_num) | |
1166 | { | |
49dce689 | 1167 | struct device *dev; |
1e9a51dc | 1168 | struct spi_master *master = NULL; |
5ed2c832 | 1169 | |
695794ae | 1170 | dev = class_find_device(&spi_master_class, NULL, &bus_num, |
5ed2c832 DY |
1171 | __spi_master_match); |
1172 | if (dev) | |
1173 | master = container_of(dev, struct spi_master, dev); | |
1174 | /* reference got in class_find_device */ | |
1e9a51dc | 1175 | return master; |
8ae12a0d DB |
1176 | } |
1177 | EXPORT_SYMBOL_GPL(spi_busnum_to_master); | |
1178 | ||
1179 | ||
1180 | /*-------------------------------------------------------------------------*/ | |
1181 | ||
7d077197 DB |
1182 | /* Core methods for SPI master protocol drivers. Some of the |
1183 | * other core methods are currently defined as inline functions. | |
1184 | */ | |
1185 | ||
1186 | /** | |
1187 | * spi_setup - setup SPI mode and clock rate | |
1188 | * @spi: the device whose settings are being modified | |
1189 | * Context: can sleep, and no requests are queued to the device | |
1190 | * | |
1191 | * SPI protocol drivers may need to update the transfer mode if the | |
1192 | * device doesn't work with its default. They may likewise need | |
1193 | * to update clock rates or word sizes from initial values. This function | |
1194 | * changes those settings, and must be called from a context that can sleep. | |
1195 | * Except for SPI_CS_HIGH, which takes effect immediately, the changes take | |
1196 | * effect the next time the device is selected and data is transferred to | |
1197 | * or from it. When this function returns, the spi device is deselected. | |
1198 | * | |
1199 | * Note that this call will fail if the protocol driver specifies an option | |
1200 | * that the underlying controller or its driver does not support. For | |
1201 | * example, not all hardware supports wire transfers using nine bit words, | |
1202 | * LSB-first wire encoding, or active-high chipselects. | |
1203 | */ | |
1204 | int spi_setup(struct spi_device *spi) | |
1205 | { | |
e7db06b5 | 1206 | unsigned bad_bits; |
caae070c | 1207 | int status = 0; |
7d077197 | 1208 | |
e7db06b5 DB |
1209 | /* help drivers fail *cleanly* when they need options |
1210 | * that aren't supported with their current master | |
1211 | */ | |
1212 | bad_bits = spi->mode & ~spi->master->mode_bits; | |
1213 | if (bad_bits) { | |
eb288a1f | 1214 | dev_err(&spi->dev, "setup: unsupported mode bits %x\n", |
e7db06b5 DB |
1215 | bad_bits); |
1216 | return -EINVAL; | |
1217 | } | |
1218 | ||
7d077197 DB |
1219 | if (!spi->bits_per_word) |
1220 | spi->bits_per_word = 8; | |
1221 | ||
caae070c LD |
1222 | if (spi->master->setup) |
1223 | status = spi->master->setup(spi); | |
7d077197 DB |
1224 | |
1225 | dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s" | |
1226 | "%u bits/w, %u Hz max --> %d\n", | |
1227 | (int) (spi->mode & (SPI_CPOL | SPI_CPHA)), | |
1228 | (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "", | |
1229 | (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "", | |
1230 | (spi->mode & SPI_3WIRE) ? "3wire, " : "", | |
1231 | (spi->mode & SPI_LOOP) ? "loopback, " : "", | |
1232 | spi->bits_per_word, spi->max_speed_hz, | |
1233 | status); | |
1234 | ||
1235 | return status; | |
1236 | } | |
1237 | EXPORT_SYMBOL_GPL(spi_setup); | |
1238 | ||
cf32b71e ES |
1239 | static int __spi_async(struct spi_device *spi, struct spi_message *message) |
1240 | { | |
1241 | struct spi_master *master = spi->master; | |
e6811d1d | 1242 | struct spi_transfer *xfer; |
cf32b71e ES |
1243 | |
1244 | /* Half-duplex links include original MicroWire, and ones with | |
1245 | * only one data pin like SPI_3WIRE (switches direction) or where | |
1246 | * either MOSI or MISO is missing. They can also be caused by | |
1247 | * software limitations. | |
1248 | */ | |
1249 | if ((master->flags & SPI_MASTER_HALF_DUPLEX) | |
1250 | || (spi->mode & SPI_3WIRE)) { | |
cf32b71e ES |
1251 | unsigned flags = master->flags; |
1252 | ||
1253 | list_for_each_entry(xfer, &message->transfers, transfer_list) { | |
1254 | if (xfer->rx_buf && xfer->tx_buf) | |
1255 | return -EINVAL; | |
1256 | if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf) | |
1257 | return -EINVAL; | |
1258 | if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf) | |
1259 | return -EINVAL; | |
1260 | } | |
1261 | } | |
1262 | ||
e6811d1d LD |
1263 | /** |
1264 | * Set transfer bits_per_word as spi device default if it is not | |
1265 | * set for this transfer. | |
1266 | */ | |
1267 | list_for_each_entry(xfer, &message->transfers, transfer_list) { | |
1268 | if (!xfer->bits_per_word) | |
1269 | xfer->bits_per_word = spi->bits_per_word; | |
1270 | } | |
1271 | ||
cf32b71e ES |
1272 | message->spi = spi; |
1273 | message->status = -EINPROGRESS; | |
1274 | return master->transfer(spi, message); | |
1275 | } | |
1276 | ||
568d0697 DB |
1277 | /** |
1278 | * spi_async - asynchronous SPI transfer | |
1279 | * @spi: device with which data will be exchanged | |
1280 | * @message: describes the data transfers, including completion callback | |
1281 | * Context: any (irqs may be blocked, etc) | |
1282 | * | |
1283 | * This call may be used in_irq and other contexts which can't sleep, | |
1284 | * as well as from task contexts which can sleep. | |
1285 | * | |
1286 | * The completion callback is invoked in a context which can't sleep. | |
1287 | * Before that invocation, the value of message->status is undefined. | |
1288 | * When the callback is issued, message->status holds either zero (to | |
1289 | * indicate complete success) or a negative error code. After that | |
1290 | * callback returns, the driver which issued the transfer request may | |
1291 | * deallocate the associated memory; it's no longer in use by any SPI | |
1292 | * core or controller driver code. | |
1293 | * | |
1294 | * Note that although all messages to a spi_device are handled in | |
1295 | * FIFO order, messages may go to different devices in other orders. | |
1296 | * Some device might be higher priority, or have various "hard" access | |
1297 | * time requirements, for example. | |
1298 | * | |
1299 | * On detection of any fault during the transfer, processing of | |
1300 | * the entire message is aborted, and the device is deselected. | |
1301 | * Until returning from the associated message completion callback, | |
1302 | * no other spi_message queued to that device will be processed. | |
1303 | * (This rule applies equally to all the synchronous transfer calls, | |
1304 | * which are wrappers around this core asynchronous primitive.) | |
1305 | */ | |
1306 | int spi_async(struct spi_device *spi, struct spi_message *message) | |
1307 | { | |
1308 | struct spi_master *master = spi->master; | |
cf32b71e ES |
1309 | int ret; |
1310 | unsigned long flags; | |
568d0697 | 1311 | |
cf32b71e | 1312 | spin_lock_irqsave(&master->bus_lock_spinlock, flags); |
568d0697 | 1313 | |
cf32b71e ES |
1314 | if (master->bus_lock_flag) |
1315 | ret = -EBUSY; | |
1316 | else | |
1317 | ret = __spi_async(spi, message); | |
568d0697 | 1318 | |
cf32b71e ES |
1319 | spin_unlock_irqrestore(&master->bus_lock_spinlock, flags); |
1320 | ||
1321 | return ret; | |
568d0697 DB |
1322 | } |
1323 | EXPORT_SYMBOL_GPL(spi_async); | |
1324 | ||
cf32b71e ES |
1325 | /** |
1326 | * spi_async_locked - version of spi_async with exclusive bus usage | |
1327 | * @spi: device with which data will be exchanged | |
1328 | * @message: describes the data transfers, including completion callback | |
1329 | * Context: any (irqs may be blocked, etc) | |
1330 | * | |
1331 | * This call may be used in_irq and other contexts which can't sleep, | |
1332 | * as well as from task contexts which can sleep. | |
1333 | * | |
1334 | * The completion callback is invoked in a context which can't sleep. | |
1335 | * Before that invocation, the value of message->status is undefined. | |
1336 | * When the callback is issued, message->status holds either zero (to | |
1337 | * indicate complete success) or a negative error code. After that | |
1338 | * callback returns, the driver which issued the transfer request may | |
1339 | * deallocate the associated memory; it's no longer in use by any SPI | |
1340 | * core or controller driver code. | |
1341 | * | |
1342 | * Note that although all messages to a spi_device are handled in | |
1343 | * FIFO order, messages may go to different devices in other orders. | |
1344 | * Some device might be higher priority, or have various "hard" access | |
1345 | * time requirements, for example. | |
1346 | * | |
1347 | * On detection of any fault during the transfer, processing of | |
1348 | * the entire message is aborted, and the device is deselected. | |
1349 | * Until returning from the associated message completion callback, | |
1350 | * no other spi_message queued to that device will be processed. | |
1351 | * (This rule applies equally to all the synchronous transfer calls, | |
1352 | * which are wrappers around this core asynchronous primitive.) | |
1353 | */ | |
1354 | int spi_async_locked(struct spi_device *spi, struct spi_message *message) | |
1355 | { | |
1356 | struct spi_master *master = spi->master; | |
1357 | int ret; | |
1358 | unsigned long flags; | |
1359 | ||
1360 | spin_lock_irqsave(&master->bus_lock_spinlock, flags); | |
1361 | ||
1362 | ret = __spi_async(spi, message); | |
1363 | ||
1364 | spin_unlock_irqrestore(&master->bus_lock_spinlock, flags); | |
1365 | ||
1366 | return ret; | |
1367 | ||
1368 | } | |
1369 | EXPORT_SYMBOL_GPL(spi_async_locked); | |
1370 | ||
7d077197 DB |
1371 | |
1372 | /*-------------------------------------------------------------------------*/ | |
1373 | ||
1374 | /* Utility methods for SPI master protocol drivers, layered on | |
1375 | * top of the core. Some other utility methods are defined as | |
1376 | * inline functions. | |
1377 | */ | |
1378 | ||
5d870c8e AM |
1379 | static void spi_complete(void *arg) |
1380 | { | |
1381 | complete(arg); | |
1382 | } | |
1383 | ||
cf32b71e ES |
1384 | static int __spi_sync(struct spi_device *spi, struct spi_message *message, |
1385 | int bus_locked) | |
1386 | { | |
1387 | DECLARE_COMPLETION_ONSTACK(done); | |
1388 | int status; | |
1389 | struct spi_master *master = spi->master; | |
1390 | ||
1391 | message->complete = spi_complete; | |
1392 | message->context = &done; | |
1393 | ||
1394 | if (!bus_locked) | |
1395 | mutex_lock(&master->bus_lock_mutex); | |
1396 | ||
1397 | status = spi_async_locked(spi, message); | |
1398 | ||
1399 | if (!bus_locked) | |
1400 | mutex_unlock(&master->bus_lock_mutex); | |
1401 | ||
1402 | if (status == 0) { | |
1403 | wait_for_completion(&done); | |
1404 | status = message->status; | |
1405 | } | |
1406 | message->context = NULL; | |
1407 | return status; | |
1408 | } | |
1409 | ||
8ae12a0d DB |
1410 | /** |
1411 | * spi_sync - blocking/synchronous SPI data transfers | |
1412 | * @spi: device with which data will be exchanged | |
1413 | * @message: describes the data transfers | |
33e34dc6 | 1414 | * Context: can sleep |
8ae12a0d DB |
1415 | * |
1416 | * This call may only be used from a context that may sleep. The sleep | |
1417 | * is non-interruptible, and has no timeout. Low-overhead controller | |
1418 | * drivers may DMA directly into and out of the message buffers. | |
1419 | * | |
1420 | * Note that the SPI device's chip select is active during the message, | |
1421 | * and then is normally disabled between messages. Drivers for some | |
1422 | * frequently-used devices may want to minimize costs of selecting a chip, | |
1423 | * by leaving it selected in anticipation that the next message will go | |
1424 | * to the same chip. (That may increase power usage.) | |
1425 | * | |
0c868461 DB |
1426 | * Also, the caller is guaranteeing that the memory associated with the |
1427 | * message will not be freed before this call returns. | |
1428 | * | |
9b938b74 | 1429 | * It returns zero on success, else a negative error code. |
8ae12a0d DB |
1430 | */ |
1431 | int spi_sync(struct spi_device *spi, struct spi_message *message) | |
1432 | { | |
cf32b71e | 1433 | return __spi_sync(spi, message, 0); |
8ae12a0d DB |
1434 | } |
1435 | EXPORT_SYMBOL_GPL(spi_sync); | |
1436 | ||
cf32b71e ES |
1437 | /** |
1438 | * spi_sync_locked - version of spi_sync with exclusive bus usage | |
1439 | * @spi: device with which data will be exchanged | |
1440 | * @message: describes the data transfers | |
1441 | * Context: can sleep | |
1442 | * | |
1443 | * This call may only be used from a context that may sleep. The sleep | |
1444 | * is non-interruptible, and has no timeout. Low-overhead controller | |
1445 | * drivers may DMA directly into and out of the message buffers. | |
1446 | * | |
1447 | * This call should be used by drivers that require exclusive access to the | |
25985edc | 1448 | * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must |
cf32b71e ES |
1449 | * be released by a spi_bus_unlock call when the exclusive access is over. |
1450 | * | |
1451 | * It returns zero on success, else a negative error code. | |
1452 | */ | |
1453 | int spi_sync_locked(struct spi_device *spi, struct spi_message *message) | |
1454 | { | |
1455 | return __spi_sync(spi, message, 1); | |
1456 | } | |
1457 | EXPORT_SYMBOL_GPL(spi_sync_locked); | |
1458 | ||
1459 | /** | |
1460 | * spi_bus_lock - obtain a lock for exclusive SPI bus usage | |
1461 | * @master: SPI bus master that should be locked for exclusive bus access | |
1462 | * Context: can sleep | |
1463 | * | |
1464 | * This call may only be used from a context that may sleep. The sleep | |
1465 | * is non-interruptible, and has no timeout. | |
1466 | * | |
1467 | * This call should be used by drivers that require exclusive access to the | |
1468 | * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the | |
1469 | * exclusive access is over. Data transfer must be done by spi_sync_locked | |
1470 | * and spi_async_locked calls when the SPI bus lock is held. | |
1471 | * | |
1472 | * It returns zero on success, else a negative error code. | |
1473 | */ | |
1474 | int spi_bus_lock(struct spi_master *master) | |
1475 | { | |
1476 | unsigned long flags; | |
1477 | ||
1478 | mutex_lock(&master->bus_lock_mutex); | |
1479 | ||
1480 | spin_lock_irqsave(&master->bus_lock_spinlock, flags); | |
1481 | master->bus_lock_flag = 1; | |
1482 | spin_unlock_irqrestore(&master->bus_lock_spinlock, flags); | |
1483 | ||
1484 | /* mutex remains locked until spi_bus_unlock is called */ | |
1485 | ||
1486 | return 0; | |
1487 | } | |
1488 | EXPORT_SYMBOL_GPL(spi_bus_lock); | |
1489 | ||
1490 | /** | |
1491 | * spi_bus_unlock - release the lock for exclusive SPI bus usage | |
1492 | * @master: SPI bus master that was locked for exclusive bus access | |
1493 | * Context: can sleep | |
1494 | * | |
1495 | * This call may only be used from a context that may sleep. The sleep | |
1496 | * is non-interruptible, and has no timeout. | |
1497 | * | |
1498 | * This call releases an SPI bus lock previously obtained by an spi_bus_lock | |
1499 | * call. | |
1500 | * | |
1501 | * It returns zero on success, else a negative error code. | |
1502 | */ | |
1503 | int spi_bus_unlock(struct spi_master *master) | |
1504 | { | |
1505 | master->bus_lock_flag = 0; | |
1506 | ||
1507 | mutex_unlock(&master->bus_lock_mutex); | |
1508 | ||
1509 | return 0; | |
1510 | } | |
1511 | EXPORT_SYMBOL_GPL(spi_bus_unlock); | |
1512 | ||
a9948b61 DB |
1513 | /* portable code must never pass more than 32 bytes */ |
1514 | #define SPI_BUFSIZ max(32,SMP_CACHE_BYTES) | |
8ae12a0d DB |
1515 | |
1516 | static u8 *buf; | |
1517 | ||
1518 | /** | |
1519 | * spi_write_then_read - SPI synchronous write followed by read | |
1520 | * @spi: device with which data will be exchanged | |
1521 | * @txbuf: data to be written (need not be dma-safe) | |
1522 | * @n_tx: size of txbuf, in bytes | |
27570497 JP |
1523 | * @rxbuf: buffer into which data will be read (need not be dma-safe) |
1524 | * @n_rx: size of rxbuf, in bytes | |
33e34dc6 | 1525 | * Context: can sleep |
8ae12a0d DB |
1526 | * |
1527 | * This performs a half duplex MicroWire style transaction with the | |
1528 | * device, sending txbuf and then reading rxbuf. The return value | |
1529 | * is zero for success, else a negative errno status code. | |
b885244e | 1530 | * This call may only be used from a context that may sleep. |
8ae12a0d | 1531 | * |
0c868461 | 1532 | * Parameters to this routine are always copied using a small buffer; |
33e34dc6 DB |
1533 | * portable code should never use this for more than 32 bytes. |
1534 | * Performance-sensitive or bulk transfer code should instead use | |
0c868461 | 1535 | * spi_{async,sync}() calls with dma-safe buffers. |
8ae12a0d DB |
1536 | */ |
1537 | int spi_write_then_read(struct spi_device *spi, | |
0c4a1590 MB |
1538 | const void *txbuf, unsigned n_tx, |
1539 | void *rxbuf, unsigned n_rx) | |
8ae12a0d | 1540 | { |
068f4070 | 1541 | static DEFINE_MUTEX(lock); |
8ae12a0d DB |
1542 | |
1543 | int status; | |
1544 | struct spi_message message; | |
bdff549e | 1545 | struct spi_transfer x[2]; |
8ae12a0d DB |
1546 | u8 *local_buf; |
1547 | ||
b3a223ee MB |
1548 | /* Use preallocated DMA-safe buffer if we can. We can't avoid |
1549 | * copying here, (as a pure convenience thing), but we can | |
1550 | * keep heap costs out of the hot path unless someone else is | |
1551 | * using the pre-allocated buffer or the transfer is too large. | |
8ae12a0d | 1552 | */ |
b3a223ee | 1553 | if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) { |
5323f498 | 1554 | local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx), GFP_KERNEL); |
b3a223ee MB |
1555 | if (!local_buf) |
1556 | return -ENOMEM; | |
1557 | } else { | |
1558 | local_buf = buf; | |
1559 | } | |
8ae12a0d | 1560 | |
8275c642 | 1561 | spi_message_init(&message); |
bdff549e DB |
1562 | memset(x, 0, sizeof x); |
1563 | if (n_tx) { | |
1564 | x[0].len = n_tx; | |
1565 | spi_message_add_tail(&x[0], &message); | |
1566 | } | |
1567 | if (n_rx) { | |
1568 | x[1].len = n_rx; | |
1569 | spi_message_add_tail(&x[1], &message); | |
1570 | } | |
8275c642 | 1571 | |
8ae12a0d | 1572 | memcpy(local_buf, txbuf, n_tx); |
bdff549e DB |
1573 | x[0].tx_buf = local_buf; |
1574 | x[1].rx_buf = local_buf + n_tx; | |
8ae12a0d DB |
1575 | |
1576 | /* do the i/o */ | |
8ae12a0d | 1577 | status = spi_sync(spi, &message); |
9b938b74 | 1578 | if (status == 0) |
bdff549e | 1579 | memcpy(rxbuf, x[1].rx_buf, n_rx); |
8ae12a0d | 1580 | |
bdff549e | 1581 | if (x[0].tx_buf == buf) |
068f4070 | 1582 | mutex_unlock(&lock); |
8ae12a0d DB |
1583 | else |
1584 | kfree(local_buf); | |
1585 | ||
1586 | return status; | |
1587 | } | |
1588 | EXPORT_SYMBOL_GPL(spi_write_then_read); | |
1589 | ||
1590 | /*-------------------------------------------------------------------------*/ | |
1591 | ||
1592 | static int __init spi_init(void) | |
1593 | { | |
b885244e DB |
1594 | int status; |
1595 | ||
e94b1766 | 1596 | buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL); |
b885244e DB |
1597 | if (!buf) { |
1598 | status = -ENOMEM; | |
1599 | goto err0; | |
1600 | } | |
1601 | ||
1602 | status = bus_register(&spi_bus_type); | |
1603 | if (status < 0) | |
1604 | goto err1; | |
8ae12a0d | 1605 | |
b885244e DB |
1606 | status = class_register(&spi_master_class); |
1607 | if (status < 0) | |
1608 | goto err2; | |
8ae12a0d | 1609 | return 0; |
b885244e DB |
1610 | |
1611 | err2: | |
1612 | bus_unregister(&spi_bus_type); | |
1613 | err1: | |
1614 | kfree(buf); | |
1615 | buf = NULL; | |
1616 | err0: | |
1617 | return status; | |
8ae12a0d | 1618 | } |
b885244e | 1619 | |
8ae12a0d DB |
1620 | /* board_info is normally registered in arch_initcall(), |
1621 | * but even essential drivers wait till later | |
b885244e DB |
1622 | * |
1623 | * REVISIT only boardinfo really needs static linking. the rest (device and | |
1624 | * driver registration) _could_ be dynamically linked (modular) ... costs | |
1625 | * include needing to have boardinfo data structures be much more public. | |
8ae12a0d | 1626 | */ |
673c0c00 | 1627 | postcore_initcall(spi_init); |
8ae12a0d | 1628 |