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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> |
8bd75c77 | 36 | #include <linux/sched/rt.h> |
ffbbdd21 LW |
37 | #include <linux/delay.h> |
38 | #include <linux/kthread.h> | |
64bee4d2 MW |
39 | #include <linux/ioport.h> |
40 | #include <linux/acpi.h> | |
8ae12a0d | 41 | |
8ae12a0d DB |
42 | static void spidev_release(struct device *dev) |
43 | { | |
0ffa0285 | 44 | struct spi_device *spi = to_spi_device(dev); |
8ae12a0d DB |
45 | |
46 | /* spi masters may cleanup for released devices */ | |
47 | if (spi->master->cleanup) | |
48 | spi->master->cleanup(spi); | |
49 | ||
0c868461 | 50 | spi_master_put(spi->master); |
07a389fe | 51 | kfree(spi); |
8ae12a0d DB |
52 | } |
53 | ||
54 | static ssize_t | |
55 | modalias_show(struct device *dev, struct device_attribute *a, char *buf) | |
56 | { | |
57 | const struct spi_device *spi = to_spi_device(dev); | |
58 | ||
d8e328b3 | 59 | return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias); |
8ae12a0d | 60 | } |
aa7da564 | 61 | static DEVICE_ATTR_RO(modalias); |
8ae12a0d | 62 | |
aa7da564 GKH |
63 | static struct attribute *spi_dev_attrs[] = { |
64 | &dev_attr_modalias.attr, | |
65 | NULL, | |
8ae12a0d | 66 | }; |
aa7da564 | 67 | ATTRIBUTE_GROUPS(spi_dev); |
8ae12a0d DB |
68 | |
69 | /* modalias support makes "modprobe $MODALIAS" new-style hotplug work, | |
70 | * and the sysfs version makes coldplug work too. | |
71 | */ | |
72 | ||
75368bf6 AV |
73 | static const struct spi_device_id *spi_match_id(const struct spi_device_id *id, |
74 | const struct spi_device *sdev) | |
75 | { | |
76 | while (id->name[0]) { | |
77 | if (!strcmp(sdev->modalias, id->name)) | |
78 | return id; | |
79 | id++; | |
80 | } | |
81 | return NULL; | |
82 | } | |
83 | ||
84 | const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev) | |
85 | { | |
86 | const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver); | |
87 | ||
88 | return spi_match_id(sdrv->id_table, sdev); | |
89 | } | |
90 | EXPORT_SYMBOL_GPL(spi_get_device_id); | |
91 | ||
8ae12a0d DB |
92 | static int spi_match_device(struct device *dev, struct device_driver *drv) |
93 | { | |
94 | const struct spi_device *spi = to_spi_device(dev); | |
75368bf6 AV |
95 | const struct spi_driver *sdrv = to_spi_driver(drv); |
96 | ||
2b7a32f7 SA |
97 | /* Attempt an OF style match */ |
98 | if (of_driver_match_device(dev, drv)) | |
99 | return 1; | |
100 | ||
64bee4d2 MW |
101 | /* Then try ACPI */ |
102 | if (acpi_driver_match_device(dev, drv)) | |
103 | return 1; | |
104 | ||
75368bf6 AV |
105 | if (sdrv->id_table) |
106 | return !!spi_match_id(sdrv->id_table, spi); | |
8ae12a0d | 107 | |
35f74fca | 108 | return strcmp(spi->modalias, drv->name) == 0; |
8ae12a0d DB |
109 | } |
110 | ||
7eff2e7a | 111 | static int spi_uevent(struct device *dev, struct kobj_uevent_env *env) |
8ae12a0d DB |
112 | { |
113 | const struct spi_device *spi = to_spi_device(dev); | |
114 | ||
e0626e38 | 115 | add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias); |
8ae12a0d DB |
116 | return 0; |
117 | } | |
118 | ||
3ae22e8c MB |
119 | #ifdef CONFIG_PM_SLEEP |
120 | static int spi_legacy_suspend(struct device *dev, pm_message_t message) | |
8ae12a0d | 121 | { |
3c72426f | 122 | int value = 0; |
b885244e | 123 | struct spi_driver *drv = to_spi_driver(dev->driver); |
8ae12a0d | 124 | |
8ae12a0d | 125 | /* suspend will stop irqs and dma; no more i/o */ |
3c72426f DB |
126 | if (drv) { |
127 | if (drv->suspend) | |
128 | value = drv->suspend(to_spi_device(dev), message); | |
129 | else | |
130 | dev_dbg(dev, "... can't suspend\n"); | |
131 | } | |
8ae12a0d DB |
132 | return value; |
133 | } | |
134 | ||
3ae22e8c | 135 | static int spi_legacy_resume(struct device *dev) |
8ae12a0d | 136 | { |
3c72426f | 137 | int value = 0; |
b885244e | 138 | struct spi_driver *drv = to_spi_driver(dev->driver); |
8ae12a0d | 139 | |
8ae12a0d | 140 | /* resume may restart the i/o queue */ |
3c72426f DB |
141 | if (drv) { |
142 | if (drv->resume) | |
143 | value = drv->resume(to_spi_device(dev)); | |
144 | else | |
145 | dev_dbg(dev, "... can't resume\n"); | |
146 | } | |
8ae12a0d DB |
147 | return value; |
148 | } | |
149 | ||
3ae22e8c MB |
150 | static int spi_pm_suspend(struct device *dev) |
151 | { | |
152 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
153 | ||
154 | if (pm) | |
155 | return pm_generic_suspend(dev); | |
156 | else | |
157 | return spi_legacy_suspend(dev, PMSG_SUSPEND); | |
158 | } | |
159 | ||
160 | static int spi_pm_resume(struct device *dev) | |
161 | { | |
162 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
163 | ||
164 | if (pm) | |
165 | return pm_generic_resume(dev); | |
166 | else | |
167 | return spi_legacy_resume(dev); | |
168 | } | |
169 | ||
170 | static int spi_pm_freeze(struct device *dev) | |
171 | { | |
172 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
173 | ||
174 | if (pm) | |
175 | return pm_generic_freeze(dev); | |
176 | else | |
177 | return spi_legacy_suspend(dev, PMSG_FREEZE); | |
178 | } | |
179 | ||
180 | static int spi_pm_thaw(struct device *dev) | |
181 | { | |
182 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
183 | ||
184 | if (pm) | |
185 | return pm_generic_thaw(dev); | |
186 | else | |
187 | return spi_legacy_resume(dev); | |
188 | } | |
189 | ||
190 | static int spi_pm_poweroff(struct device *dev) | |
191 | { | |
192 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
193 | ||
194 | if (pm) | |
195 | return pm_generic_poweroff(dev); | |
196 | else | |
197 | return spi_legacy_suspend(dev, PMSG_HIBERNATE); | |
198 | } | |
199 | ||
200 | static int spi_pm_restore(struct device *dev) | |
201 | { | |
202 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
203 | ||
204 | if (pm) | |
205 | return pm_generic_restore(dev); | |
206 | else | |
207 | return spi_legacy_resume(dev); | |
208 | } | |
8ae12a0d | 209 | #else |
3ae22e8c MB |
210 | #define spi_pm_suspend NULL |
211 | #define spi_pm_resume NULL | |
212 | #define spi_pm_freeze NULL | |
213 | #define spi_pm_thaw NULL | |
214 | #define spi_pm_poweroff NULL | |
215 | #define spi_pm_restore NULL | |
8ae12a0d DB |
216 | #endif |
217 | ||
3ae22e8c MB |
218 | static const struct dev_pm_ops spi_pm = { |
219 | .suspend = spi_pm_suspend, | |
220 | .resume = spi_pm_resume, | |
221 | .freeze = spi_pm_freeze, | |
222 | .thaw = spi_pm_thaw, | |
223 | .poweroff = spi_pm_poweroff, | |
224 | .restore = spi_pm_restore, | |
225 | SET_RUNTIME_PM_OPS( | |
226 | pm_generic_runtime_suspend, | |
227 | pm_generic_runtime_resume, | |
45f0a85c | 228 | NULL |
3ae22e8c MB |
229 | ) |
230 | }; | |
231 | ||
8ae12a0d DB |
232 | struct bus_type spi_bus_type = { |
233 | .name = "spi", | |
aa7da564 | 234 | .dev_groups = spi_dev_groups, |
8ae12a0d DB |
235 | .match = spi_match_device, |
236 | .uevent = spi_uevent, | |
3ae22e8c | 237 | .pm = &spi_pm, |
8ae12a0d DB |
238 | }; |
239 | EXPORT_SYMBOL_GPL(spi_bus_type); | |
240 | ||
b885244e DB |
241 | |
242 | static int spi_drv_probe(struct device *dev) | |
243 | { | |
244 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); | |
245 | ||
246 | return sdrv->probe(to_spi_device(dev)); | |
247 | } | |
248 | ||
249 | static int spi_drv_remove(struct device *dev) | |
250 | { | |
251 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); | |
252 | ||
253 | return sdrv->remove(to_spi_device(dev)); | |
254 | } | |
255 | ||
256 | static void spi_drv_shutdown(struct device *dev) | |
257 | { | |
258 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); | |
259 | ||
260 | sdrv->shutdown(to_spi_device(dev)); | |
261 | } | |
262 | ||
33e34dc6 DB |
263 | /** |
264 | * spi_register_driver - register a SPI driver | |
265 | * @sdrv: the driver to register | |
266 | * Context: can sleep | |
267 | */ | |
b885244e DB |
268 | int spi_register_driver(struct spi_driver *sdrv) |
269 | { | |
270 | sdrv->driver.bus = &spi_bus_type; | |
271 | if (sdrv->probe) | |
272 | sdrv->driver.probe = spi_drv_probe; | |
273 | if (sdrv->remove) | |
274 | sdrv->driver.remove = spi_drv_remove; | |
275 | if (sdrv->shutdown) | |
276 | sdrv->driver.shutdown = spi_drv_shutdown; | |
277 | return driver_register(&sdrv->driver); | |
278 | } | |
279 | EXPORT_SYMBOL_GPL(spi_register_driver); | |
280 | ||
8ae12a0d DB |
281 | /*-------------------------------------------------------------------------*/ |
282 | ||
283 | /* SPI devices should normally not be created by SPI device drivers; that | |
284 | * would make them board-specific. Similarly with SPI master drivers. | |
285 | * Device registration normally goes into like arch/.../mach.../board-YYY.c | |
286 | * with other readonly (flashable) information about mainboard devices. | |
287 | */ | |
288 | ||
289 | struct boardinfo { | |
290 | struct list_head list; | |
2b9603a0 | 291 | struct spi_board_info board_info; |
8ae12a0d DB |
292 | }; |
293 | ||
294 | static LIST_HEAD(board_list); | |
2b9603a0 FT |
295 | static LIST_HEAD(spi_master_list); |
296 | ||
297 | /* | |
298 | * Used to protect add/del opertion for board_info list and | |
299 | * spi_master list, and their matching process | |
300 | */ | |
94040828 | 301 | static DEFINE_MUTEX(board_lock); |
8ae12a0d | 302 | |
dc87c98e GL |
303 | /** |
304 | * spi_alloc_device - Allocate a new SPI device | |
305 | * @master: Controller to which device is connected | |
306 | * Context: can sleep | |
307 | * | |
308 | * Allows a driver to allocate and initialize a spi_device without | |
309 | * registering it immediately. This allows a driver to directly | |
310 | * fill the spi_device with device parameters before calling | |
311 | * spi_add_device() on it. | |
312 | * | |
313 | * Caller is responsible to call spi_add_device() on the returned | |
314 | * spi_device structure to add it to the SPI master. If the caller | |
315 | * needs to discard the spi_device without adding it, then it should | |
316 | * call spi_dev_put() on it. | |
317 | * | |
318 | * Returns a pointer to the new device, or NULL. | |
319 | */ | |
320 | struct spi_device *spi_alloc_device(struct spi_master *master) | |
321 | { | |
322 | struct spi_device *spi; | |
323 | struct device *dev = master->dev.parent; | |
324 | ||
325 | if (!spi_master_get(master)) | |
326 | return NULL; | |
327 | ||
328 | spi = kzalloc(sizeof *spi, GFP_KERNEL); | |
329 | if (!spi) { | |
330 | dev_err(dev, "cannot alloc spi_device\n"); | |
331 | spi_master_put(master); | |
332 | return NULL; | |
333 | } | |
334 | ||
335 | spi->master = master; | |
178db7d3 | 336 | spi->dev.parent = &master->dev; |
dc87c98e GL |
337 | spi->dev.bus = &spi_bus_type; |
338 | spi->dev.release = spidev_release; | |
446411e1 | 339 | spi->cs_gpio = -ENOENT; |
dc87c98e GL |
340 | device_initialize(&spi->dev); |
341 | return spi; | |
342 | } | |
343 | EXPORT_SYMBOL_GPL(spi_alloc_device); | |
344 | ||
345 | /** | |
346 | * spi_add_device - Add spi_device allocated with spi_alloc_device | |
347 | * @spi: spi_device to register | |
348 | * | |
349 | * Companion function to spi_alloc_device. Devices allocated with | |
350 | * spi_alloc_device can be added onto the spi bus with this function. | |
351 | * | |
e48880e0 | 352 | * Returns 0 on success; negative errno on failure |
dc87c98e GL |
353 | */ |
354 | int spi_add_device(struct spi_device *spi) | |
355 | { | |
e48880e0 | 356 | static DEFINE_MUTEX(spi_add_lock); |
74317984 JCPV |
357 | struct spi_master *master = spi->master; |
358 | struct device *dev = master->dev.parent; | |
8ec130a0 | 359 | struct device *d; |
dc87c98e GL |
360 | int status; |
361 | ||
362 | /* Chipselects are numbered 0..max; validate. */ | |
74317984 | 363 | if (spi->chip_select >= master->num_chipselect) { |
dc87c98e GL |
364 | dev_err(dev, "cs%d >= max %d\n", |
365 | spi->chip_select, | |
74317984 | 366 | master->num_chipselect); |
dc87c98e GL |
367 | return -EINVAL; |
368 | } | |
369 | ||
370 | /* Set the bus ID string */ | |
35f74fca | 371 | dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev), |
dc87c98e GL |
372 | spi->chip_select); |
373 | ||
e48880e0 DB |
374 | |
375 | /* We need to make sure there's no other device with this | |
376 | * chipselect **BEFORE** we call setup(), else we'll trash | |
377 | * its configuration. Lock against concurrent add() calls. | |
378 | */ | |
379 | mutex_lock(&spi_add_lock); | |
380 | ||
8ec130a0 RT |
381 | d = bus_find_device_by_name(&spi_bus_type, NULL, dev_name(&spi->dev)); |
382 | if (d != NULL) { | |
e48880e0 DB |
383 | dev_err(dev, "chipselect %d already in use\n", |
384 | spi->chip_select); | |
8ec130a0 | 385 | put_device(d); |
e48880e0 DB |
386 | status = -EBUSY; |
387 | goto done; | |
388 | } | |
389 | ||
74317984 JCPV |
390 | if (master->cs_gpios) |
391 | spi->cs_gpio = master->cs_gpios[spi->chip_select]; | |
392 | ||
e48880e0 DB |
393 | /* Drivers may modify this initial i/o setup, but will |
394 | * normally rely on the device being setup. Devices | |
395 | * using SPI_CS_HIGH can't coexist well otherwise... | |
396 | */ | |
7d077197 | 397 | status = spi_setup(spi); |
dc87c98e | 398 | if (status < 0) { |
eb288a1f LW |
399 | dev_err(dev, "can't setup %s, status %d\n", |
400 | dev_name(&spi->dev), status); | |
e48880e0 | 401 | goto done; |
dc87c98e GL |
402 | } |
403 | ||
e48880e0 | 404 | /* Device may be bound to an active driver when this returns */ |
dc87c98e | 405 | status = device_add(&spi->dev); |
e48880e0 | 406 | if (status < 0) |
eb288a1f LW |
407 | dev_err(dev, "can't add %s, status %d\n", |
408 | dev_name(&spi->dev), status); | |
e48880e0 | 409 | else |
35f74fca | 410 | dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev)); |
dc87c98e | 411 | |
e48880e0 DB |
412 | done: |
413 | mutex_unlock(&spi_add_lock); | |
414 | return status; | |
dc87c98e GL |
415 | } |
416 | EXPORT_SYMBOL_GPL(spi_add_device); | |
8ae12a0d | 417 | |
33e34dc6 DB |
418 | /** |
419 | * spi_new_device - instantiate one new SPI device | |
420 | * @master: Controller to which device is connected | |
421 | * @chip: Describes the SPI device | |
422 | * Context: can sleep | |
423 | * | |
424 | * On typical mainboards, this is purely internal; and it's not needed | |
8ae12a0d DB |
425 | * after board init creates the hard-wired devices. Some development |
426 | * platforms may not be able to use spi_register_board_info though, and | |
427 | * this is exported so that for example a USB or parport based adapter | |
428 | * driver could add devices (which it would learn about out-of-band). | |
082c8cb4 DB |
429 | * |
430 | * Returns the new device, or NULL. | |
8ae12a0d | 431 | */ |
e9d5a461 AB |
432 | struct spi_device *spi_new_device(struct spi_master *master, |
433 | struct spi_board_info *chip) | |
8ae12a0d DB |
434 | { |
435 | struct spi_device *proxy; | |
8ae12a0d DB |
436 | int status; |
437 | ||
082c8cb4 DB |
438 | /* NOTE: caller did any chip->bus_num checks necessary. |
439 | * | |
440 | * Also, unless we change the return value convention to use | |
441 | * error-or-pointer (not NULL-or-pointer), troubleshootability | |
442 | * suggests syslogged diagnostics are best here (ugh). | |
443 | */ | |
444 | ||
dc87c98e GL |
445 | proxy = spi_alloc_device(master); |
446 | if (!proxy) | |
8ae12a0d DB |
447 | return NULL; |
448 | ||
102eb975 GL |
449 | WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias)); |
450 | ||
8ae12a0d DB |
451 | proxy->chip_select = chip->chip_select; |
452 | proxy->max_speed_hz = chip->max_speed_hz; | |
980a01c9 | 453 | proxy->mode = chip->mode; |
8ae12a0d | 454 | proxy->irq = chip->irq; |
102eb975 | 455 | strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias)); |
8ae12a0d DB |
456 | proxy->dev.platform_data = (void *) chip->platform_data; |
457 | proxy->controller_data = chip->controller_data; | |
458 | proxy->controller_state = NULL; | |
8ae12a0d | 459 | |
dc87c98e | 460 | status = spi_add_device(proxy); |
8ae12a0d | 461 | if (status < 0) { |
dc87c98e GL |
462 | spi_dev_put(proxy); |
463 | return NULL; | |
8ae12a0d DB |
464 | } |
465 | ||
8ae12a0d DB |
466 | return proxy; |
467 | } | |
468 | EXPORT_SYMBOL_GPL(spi_new_device); | |
469 | ||
2b9603a0 FT |
470 | static void spi_match_master_to_boardinfo(struct spi_master *master, |
471 | struct spi_board_info *bi) | |
472 | { | |
473 | struct spi_device *dev; | |
474 | ||
475 | if (master->bus_num != bi->bus_num) | |
476 | return; | |
477 | ||
478 | dev = spi_new_device(master, bi); | |
479 | if (!dev) | |
480 | dev_err(master->dev.parent, "can't create new device for %s\n", | |
481 | bi->modalias); | |
482 | } | |
483 | ||
33e34dc6 DB |
484 | /** |
485 | * spi_register_board_info - register SPI devices for a given board | |
486 | * @info: array of chip descriptors | |
487 | * @n: how many descriptors are provided | |
488 | * Context: can sleep | |
489 | * | |
8ae12a0d DB |
490 | * Board-specific early init code calls this (probably during arch_initcall) |
491 | * with segments of the SPI device table. Any device nodes are created later, | |
492 | * after the relevant parent SPI controller (bus_num) is defined. We keep | |
493 | * this table of devices forever, so that reloading a controller driver will | |
494 | * not make Linux forget about these hard-wired devices. | |
495 | * | |
496 | * Other code can also call this, e.g. a particular add-on board might provide | |
497 | * SPI devices through its expansion connector, so code initializing that board | |
498 | * would naturally declare its SPI devices. | |
499 | * | |
500 | * The board info passed can safely be __initdata ... but be careful of | |
501 | * any embedded pointers (platform_data, etc), they're copied as-is. | |
502 | */ | |
fd4a319b | 503 | int spi_register_board_info(struct spi_board_info const *info, unsigned n) |
8ae12a0d | 504 | { |
2b9603a0 FT |
505 | struct boardinfo *bi; |
506 | int i; | |
8ae12a0d | 507 | |
2b9603a0 | 508 | bi = kzalloc(n * sizeof(*bi), GFP_KERNEL); |
8ae12a0d DB |
509 | if (!bi) |
510 | return -ENOMEM; | |
8ae12a0d | 511 | |
2b9603a0 FT |
512 | for (i = 0; i < n; i++, bi++, info++) { |
513 | struct spi_master *master; | |
8ae12a0d | 514 | |
2b9603a0 FT |
515 | memcpy(&bi->board_info, info, sizeof(*info)); |
516 | mutex_lock(&board_lock); | |
517 | list_add_tail(&bi->list, &board_list); | |
518 | list_for_each_entry(master, &spi_master_list, list) | |
519 | spi_match_master_to_boardinfo(master, &bi->board_info); | |
520 | mutex_unlock(&board_lock); | |
8ae12a0d | 521 | } |
2b9603a0 FT |
522 | |
523 | return 0; | |
8ae12a0d DB |
524 | } |
525 | ||
526 | /*-------------------------------------------------------------------------*/ | |
527 | ||
ffbbdd21 LW |
528 | /** |
529 | * spi_pump_messages - kthread work function which processes spi message queue | |
530 | * @work: pointer to kthread work struct contained in the master struct | |
531 | * | |
532 | * This function checks if there is any spi message in the queue that | |
533 | * needs processing and if so call out to the driver to initialize hardware | |
534 | * and transfer each message. | |
535 | * | |
536 | */ | |
537 | static void spi_pump_messages(struct kthread_work *work) | |
538 | { | |
539 | struct spi_master *master = | |
540 | container_of(work, struct spi_master, pump_messages); | |
541 | unsigned long flags; | |
542 | bool was_busy = false; | |
543 | int ret; | |
544 | ||
545 | /* Lock queue and check for queue work */ | |
546 | spin_lock_irqsave(&master->queue_lock, flags); | |
547 | if (list_empty(&master->queue) || !master->running) { | |
b0b36b86 BF |
548 | if (!master->busy) { |
549 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
550 | return; | |
ffbbdd21 LW |
551 | } |
552 | master->busy = false; | |
553 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
b0b36b86 BF |
554 | if (master->unprepare_transfer_hardware && |
555 | master->unprepare_transfer_hardware(master)) | |
556 | dev_err(&master->dev, | |
557 | "failed to unprepare transfer hardware\n"); | |
49834de2 MB |
558 | if (master->auto_runtime_pm) { |
559 | pm_runtime_mark_last_busy(master->dev.parent); | |
560 | pm_runtime_put_autosuspend(master->dev.parent); | |
561 | } | |
ffbbdd21 LW |
562 | return; |
563 | } | |
564 | ||
565 | /* Make sure we are not already running a message */ | |
566 | if (master->cur_msg) { | |
567 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
568 | return; | |
569 | } | |
570 | /* Extract head of queue */ | |
571 | master->cur_msg = | |
572 | list_entry(master->queue.next, struct spi_message, queue); | |
573 | ||
574 | list_del_init(&master->cur_msg->queue); | |
575 | if (master->busy) | |
576 | was_busy = true; | |
577 | else | |
578 | master->busy = true; | |
579 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
580 | ||
49834de2 MB |
581 | if (!was_busy && master->auto_runtime_pm) { |
582 | ret = pm_runtime_get_sync(master->dev.parent); | |
583 | if (ret < 0) { | |
584 | dev_err(&master->dev, "Failed to power device: %d\n", | |
585 | ret); | |
586 | return; | |
587 | } | |
588 | } | |
589 | ||
7dfd2bd7 | 590 | if (!was_busy && master->prepare_transfer_hardware) { |
ffbbdd21 LW |
591 | ret = master->prepare_transfer_hardware(master); |
592 | if (ret) { | |
593 | dev_err(&master->dev, | |
594 | "failed to prepare transfer hardware\n"); | |
49834de2 MB |
595 | |
596 | if (master->auto_runtime_pm) | |
597 | pm_runtime_put(master->dev.parent); | |
ffbbdd21 LW |
598 | return; |
599 | } | |
600 | } | |
601 | ||
602 | ret = master->transfer_one_message(master, master->cur_msg); | |
603 | if (ret) { | |
604 | dev_err(&master->dev, | |
605 | "failed to transfer one message from queue\n"); | |
606 | return; | |
607 | } | |
608 | } | |
609 | ||
610 | static int spi_init_queue(struct spi_master *master) | |
611 | { | |
612 | struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 }; | |
613 | ||
614 | INIT_LIST_HEAD(&master->queue); | |
615 | spin_lock_init(&master->queue_lock); | |
616 | ||
617 | master->running = false; | |
618 | master->busy = false; | |
619 | ||
620 | init_kthread_worker(&master->kworker); | |
621 | master->kworker_task = kthread_run(kthread_worker_fn, | |
f170168b | 622 | &master->kworker, "%s", |
ffbbdd21 LW |
623 | dev_name(&master->dev)); |
624 | if (IS_ERR(master->kworker_task)) { | |
625 | dev_err(&master->dev, "failed to create message pump task\n"); | |
626 | return -ENOMEM; | |
627 | } | |
628 | init_kthread_work(&master->pump_messages, spi_pump_messages); | |
629 | ||
630 | /* | |
631 | * Master config will indicate if this controller should run the | |
632 | * message pump with high (realtime) priority to reduce the transfer | |
633 | * latency on the bus by minimising the delay between a transfer | |
634 | * request and the scheduling of the message pump thread. Without this | |
635 | * setting the message pump thread will remain at default priority. | |
636 | */ | |
637 | if (master->rt) { | |
638 | dev_info(&master->dev, | |
639 | "will run message pump with realtime priority\n"); | |
640 | sched_setscheduler(master->kworker_task, SCHED_FIFO, ¶m); | |
641 | } | |
642 | ||
643 | return 0; | |
644 | } | |
645 | ||
646 | /** | |
647 | * spi_get_next_queued_message() - called by driver to check for queued | |
648 | * messages | |
649 | * @master: the master to check for queued messages | |
650 | * | |
651 | * If there are more messages in the queue, the next message is returned from | |
652 | * this call. | |
653 | */ | |
654 | struct spi_message *spi_get_next_queued_message(struct spi_master *master) | |
655 | { | |
656 | struct spi_message *next; | |
657 | unsigned long flags; | |
658 | ||
659 | /* get a pointer to the next message, if any */ | |
660 | spin_lock_irqsave(&master->queue_lock, flags); | |
661 | if (list_empty(&master->queue)) | |
662 | next = NULL; | |
663 | else | |
664 | next = list_entry(master->queue.next, | |
665 | struct spi_message, queue); | |
666 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
667 | ||
668 | return next; | |
669 | } | |
670 | EXPORT_SYMBOL_GPL(spi_get_next_queued_message); | |
671 | ||
672 | /** | |
673 | * spi_finalize_current_message() - the current message is complete | |
674 | * @master: the master to return the message to | |
675 | * | |
676 | * Called by the driver to notify the core that the message in the front of the | |
677 | * queue is complete and can be removed from the queue. | |
678 | */ | |
679 | void spi_finalize_current_message(struct spi_master *master) | |
680 | { | |
681 | struct spi_message *mesg; | |
682 | unsigned long flags; | |
683 | ||
684 | spin_lock_irqsave(&master->queue_lock, flags); | |
685 | mesg = master->cur_msg; | |
686 | master->cur_msg = NULL; | |
687 | ||
688 | queue_kthread_work(&master->kworker, &master->pump_messages); | |
689 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
690 | ||
691 | mesg->state = NULL; | |
692 | if (mesg->complete) | |
693 | mesg->complete(mesg->context); | |
694 | } | |
695 | EXPORT_SYMBOL_GPL(spi_finalize_current_message); | |
696 | ||
697 | static int spi_start_queue(struct spi_master *master) | |
698 | { | |
699 | unsigned long flags; | |
700 | ||
701 | spin_lock_irqsave(&master->queue_lock, flags); | |
702 | ||
703 | if (master->running || master->busy) { | |
704 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
705 | return -EBUSY; | |
706 | } | |
707 | ||
708 | master->running = true; | |
709 | master->cur_msg = NULL; | |
710 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
711 | ||
712 | queue_kthread_work(&master->kworker, &master->pump_messages); | |
713 | ||
714 | return 0; | |
715 | } | |
716 | ||
717 | static int spi_stop_queue(struct spi_master *master) | |
718 | { | |
719 | unsigned long flags; | |
720 | unsigned limit = 500; | |
721 | int ret = 0; | |
722 | ||
723 | spin_lock_irqsave(&master->queue_lock, flags); | |
724 | ||
725 | /* | |
726 | * This is a bit lame, but is optimized for the common execution path. | |
727 | * A wait_queue on the master->busy could be used, but then the common | |
728 | * execution path (pump_messages) would be required to call wake_up or | |
729 | * friends on every SPI message. Do this instead. | |
730 | */ | |
731 | while ((!list_empty(&master->queue) || master->busy) && limit--) { | |
732 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
733 | msleep(10); | |
734 | spin_lock_irqsave(&master->queue_lock, flags); | |
735 | } | |
736 | ||
737 | if (!list_empty(&master->queue) || master->busy) | |
738 | ret = -EBUSY; | |
739 | else | |
740 | master->running = false; | |
741 | ||
742 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
743 | ||
744 | if (ret) { | |
745 | dev_warn(&master->dev, | |
746 | "could not stop message queue\n"); | |
747 | return ret; | |
748 | } | |
749 | return ret; | |
750 | } | |
751 | ||
752 | static int spi_destroy_queue(struct spi_master *master) | |
753 | { | |
754 | int ret; | |
755 | ||
756 | ret = spi_stop_queue(master); | |
757 | ||
758 | /* | |
759 | * flush_kthread_worker will block until all work is done. | |
760 | * If the reason that stop_queue timed out is that the work will never | |
761 | * finish, then it does no good to call flush/stop thread, so | |
762 | * return anyway. | |
763 | */ | |
764 | if (ret) { | |
765 | dev_err(&master->dev, "problem destroying queue\n"); | |
766 | return ret; | |
767 | } | |
768 | ||
769 | flush_kthread_worker(&master->kworker); | |
770 | kthread_stop(master->kworker_task); | |
771 | ||
772 | return 0; | |
773 | } | |
774 | ||
775 | /** | |
776 | * spi_queued_transfer - transfer function for queued transfers | |
777 | * @spi: spi device which is requesting transfer | |
778 | * @msg: spi message which is to handled is queued to driver queue | |
779 | */ | |
780 | static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg) | |
781 | { | |
782 | struct spi_master *master = spi->master; | |
783 | unsigned long flags; | |
784 | ||
785 | spin_lock_irqsave(&master->queue_lock, flags); | |
786 | ||
787 | if (!master->running) { | |
788 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
789 | return -ESHUTDOWN; | |
790 | } | |
791 | msg->actual_length = 0; | |
792 | msg->status = -EINPROGRESS; | |
793 | ||
794 | list_add_tail(&msg->queue, &master->queue); | |
96b3eace | 795 | if (!master->busy) |
ffbbdd21 LW |
796 | queue_kthread_work(&master->kworker, &master->pump_messages); |
797 | ||
798 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
799 | return 0; | |
800 | } | |
801 | ||
802 | static int spi_master_initialize_queue(struct spi_master *master) | |
803 | { | |
804 | int ret; | |
805 | ||
806 | master->queued = true; | |
807 | master->transfer = spi_queued_transfer; | |
808 | ||
809 | /* Initialize and start queue */ | |
810 | ret = spi_init_queue(master); | |
811 | if (ret) { | |
812 | dev_err(&master->dev, "problem initializing queue\n"); | |
813 | goto err_init_queue; | |
814 | } | |
815 | ret = spi_start_queue(master); | |
816 | if (ret) { | |
817 | dev_err(&master->dev, "problem starting queue\n"); | |
818 | goto err_start_queue; | |
819 | } | |
820 | ||
821 | return 0; | |
822 | ||
823 | err_start_queue: | |
824 | err_init_queue: | |
825 | spi_destroy_queue(master); | |
826 | return ret; | |
827 | } | |
828 | ||
829 | /*-------------------------------------------------------------------------*/ | |
830 | ||
7cb94361 | 831 | #if defined(CONFIG_OF) |
d57a4282 GL |
832 | /** |
833 | * of_register_spi_devices() - Register child devices onto the SPI bus | |
834 | * @master: Pointer to spi_master device | |
835 | * | |
836 | * Registers an spi_device for each child node of master node which has a 'reg' | |
837 | * property. | |
838 | */ | |
839 | static void of_register_spi_devices(struct spi_master *master) | |
840 | { | |
841 | struct spi_device *spi; | |
842 | struct device_node *nc; | |
d57a4282 | 843 | int rc; |
89da4293 | 844 | u32 value; |
d57a4282 GL |
845 | |
846 | if (!master->dev.of_node) | |
847 | return; | |
848 | ||
f3b6159e | 849 | for_each_available_child_of_node(master->dev.of_node, nc) { |
d57a4282 GL |
850 | /* Alloc an spi_device */ |
851 | spi = spi_alloc_device(master); | |
852 | if (!spi) { | |
853 | dev_err(&master->dev, "spi_device alloc error for %s\n", | |
854 | nc->full_name); | |
855 | spi_dev_put(spi); | |
856 | continue; | |
857 | } | |
858 | ||
859 | /* Select device driver */ | |
860 | if (of_modalias_node(nc, spi->modalias, | |
861 | sizeof(spi->modalias)) < 0) { | |
862 | dev_err(&master->dev, "cannot find modalias for %s\n", | |
863 | nc->full_name); | |
864 | spi_dev_put(spi); | |
865 | continue; | |
866 | } | |
867 | ||
868 | /* Device address */ | |
89da4293 TP |
869 | rc = of_property_read_u32(nc, "reg", &value); |
870 | if (rc) { | |
871 | dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n", | |
872 | nc->full_name, rc); | |
d57a4282 GL |
873 | spi_dev_put(spi); |
874 | continue; | |
875 | } | |
89da4293 | 876 | spi->chip_select = value; |
d57a4282 GL |
877 | |
878 | /* Mode (clock phase/polarity/etc.) */ | |
879 | if (of_find_property(nc, "spi-cpha", NULL)) | |
880 | spi->mode |= SPI_CPHA; | |
881 | if (of_find_property(nc, "spi-cpol", NULL)) | |
882 | spi->mode |= SPI_CPOL; | |
883 | if (of_find_property(nc, "spi-cs-high", NULL)) | |
884 | spi->mode |= SPI_CS_HIGH; | |
c20151df LPC |
885 | if (of_find_property(nc, "spi-3wire", NULL)) |
886 | spi->mode |= SPI_3WIRE; | |
d57a4282 | 887 | |
f477b7fb | 888 | /* Device DUAL/QUAD mode */ |
89da4293 TP |
889 | if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) { |
890 | switch (value) { | |
891 | case 1: | |
a822e99c | 892 | break; |
89da4293 | 893 | case 2: |
a822e99c MB |
894 | spi->mode |= SPI_TX_DUAL; |
895 | break; | |
89da4293 | 896 | case 4: |
a822e99c MB |
897 | spi->mode |= SPI_TX_QUAD; |
898 | break; | |
899 | default: | |
900 | dev_err(&master->dev, | |
a110f93d | 901 | "spi-tx-bus-width %d not supported\n", |
89da4293 | 902 | value); |
a822e99c MB |
903 | spi_dev_put(spi); |
904 | continue; | |
905 | } | |
f477b7fb | 906 | } |
907 | ||
89da4293 TP |
908 | if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) { |
909 | switch (value) { | |
910 | case 1: | |
a822e99c | 911 | break; |
89da4293 | 912 | case 2: |
a822e99c MB |
913 | spi->mode |= SPI_RX_DUAL; |
914 | break; | |
89da4293 | 915 | case 4: |
a822e99c MB |
916 | spi->mode |= SPI_RX_QUAD; |
917 | break; | |
918 | default: | |
919 | dev_err(&master->dev, | |
a110f93d | 920 | "spi-rx-bus-width %d not supported\n", |
89da4293 | 921 | value); |
a822e99c MB |
922 | spi_dev_put(spi); |
923 | continue; | |
924 | } | |
f477b7fb | 925 | } |
926 | ||
d57a4282 | 927 | /* Device speed */ |
89da4293 TP |
928 | rc = of_property_read_u32(nc, "spi-max-frequency", &value); |
929 | if (rc) { | |
930 | dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n", | |
931 | nc->full_name, rc); | |
d57a4282 GL |
932 | spi_dev_put(spi); |
933 | continue; | |
934 | } | |
89da4293 | 935 | spi->max_speed_hz = value; |
d57a4282 GL |
936 | |
937 | /* IRQ */ | |
938 | spi->irq = irq_of_parse_and_map(nc, 0); | |
939 | ||
940 | /* Store a pointer to the node in the device structure */ | |
941 | of_node_get(nc); | |
942 | spi->dev.of_node = nc; | |
943 | ||
944 | /* Register the new device */ | |
70fac17c | 945 | request_module("%s%s", SPI_MODULE_PREFIX, spi->modalias); |
d57a4282 GL |
946 | rc = spi_add_device(spi); |
947 | if (rc) { | |
948 | dev_err(&master->dev, "spi_device register error %s\n", | |
949 | nc->full_name); | |
950 | spi_dev_put(spi); | |
951 | } | |
952 | ||
953 | } | |
954 | } | |
955 | #else | |
956 | static void of_register_spi_devices(struct spi_master *master) { } | |
957 | #endif | |
958 | ||
64bee4d2 MW |
959 | #ifdef CONFIG_ACPI |
960 | static int acpi_spi_add_resource(struct acpi_resource *ares, void *data) | |
961 | { | |
962 | struct spi_device *spi = data; | |
963 | ||
964 | if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) { | |
965 | struct acpi_resource_spi_serialbus *sb; | |
966 | ||
967 | sb = &ares->data.spi_serial_bus; | |
968 | if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) { | |
969 | spi->chip_select = sb->device_selection; | |
970 | spi->max_speed_hz = sb->connection_speed; | |
971 | ||
972 | if (sb->clock_phase == ACPI_SPI_SECOND_PHASE) | |
973 | spi->mode |= SPI_CPHA; | |
974 | if (sb->clock_polarity == ACPI_SPI_START_HIGH) | |
975 | spi->mode |= SPI_CPOL; | |
976 | if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH) | |
977 | spi->mode |= SPI_CS_HIGH; | |
978 | } | |
979 | } else if (spi->irq < 0) { | |
980 | struct resource r; | |
981 | ||
982 | if (acpi_dev_resource_interrupt(ares, 0, &r)) | |
983 | spi->irq = r.start; | |
984 | } | |
985 | ||
986 | /* Always tell the ACPI core to skip this resource */ | |
987 | return 1; | |
988 | } | |
989 | ||
990 | static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level, | |
991 | void *data, void **return_value) | |
992 | { | |
993 | struct spi_master *master = data; | |
994 | struct list_head resource_list; | |
995 | struct acpi_device *adev; | |
996 | struct spi_device *spi; | |
997 | int ret; | |
998 | ||
999 | if (acpi_bus_get_device(handle, &adev)) | |
1000 | return AE_OK; | |
1001 | if (acpi_bus_get_status(adev) || !adev->status.present) | |
1002 | return AE_OK; | |
1003 | ||
1004 | spi = spi_alloc_device(master); | |
1005 | if (!spi) { | |
1006 | dev_err(&master->dev, "failed to allocate SPI device for %s\n", | |
1007 | dev_name(&adev->dev)); | |
1008 | return AE_NO_MEMORY; | |
1009 | } | |
1010 | ||
1011 | ACPI_HANDLE_SET(&spi->dev, handle); | |
1012 | spi->irq = -1; | |
1013 | ||
1014 | INIT_LIST_HEAD(&resource_list); | |
1015 | ret = acpi_dev_get_resources(adev, &resource_list, | |
1016 | acpi_spi_add_resource, spi); | |
1017 | acpi_dev_free_resource_list(&resource_list); | |
1018 | ||
1019 | if (ret < 0 || !spi->max_speed_hz) { | |
1020 | spi_dev_put(spi); | |
1021 | return AE_OK; | |
1022 | } | |
1023 | ||
1024 | strlcpy(spi->modalias, dev_name(&adev->dev), sizeof(spi->modalias)); | |
1025 | if (spi_add_device(spi)) { | |
1026 | dev_err(&master->dev, "failed to add SPI device %s from ACPI\n", | |
1027 | dev_name(&adev->dev)); | |
1028 | spi_dev_put(spi); | |
1029 | } | |
1030 | ||
1031 | return AE_OK; | |
1032 | } | |
1033 | ||
1034 | static void acpi_register_spi_devices(struct spi_master *master) | |
1035 | { | |
1036 | acpi_status status; | |
1037 | acpi_handle handle; | |
1038 | ||
29896178 | 1039 | handle = ACPI_HANDLE(master->dev.parent); |
64bee4d2 MW |
1040 | if (!handle) |
1041 | return; | |
1042 | ||
1043 | status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1, | |
1044 | acpi_spi_add_device, NULL, | |
1045 | master, NULL); | |
1046 | if (ACPI_FAILURE(status)) | |
1047 | dev_warn(&master->dev, "failed to enumerate SPI slaves\n"); | |
1048 | } | |
1049 | #else | |
1050 | static inline void acpi_register_spi_devices(struct spi_master *master) {} | |
1051 | #endif /* CONFIG_ACPI */ | |
1052 | ||
49dce689 | 1053 | static void spi_master_release(struct device *dev) |
8ae12a0d DB |
1054 | { |
1055 | struct spi_master *master; | |
1056 | ||
49dce689 | 1057 | master = container_of(dev, struct spi_master, dev); |
8ae12a0d DB |
1058 | kfree(master); |
1059 | } | |
1060 | ||
1061 | static struct class spi_master_class = { | |
1062 | .name = "spi_master", | |
1063 | .owner = THIS_MODULE, | |
49dce689 | 1064 | .dev_release = spi_master_release, |
8ae12a0d DB |
1065 | }; |
1066 | ||
1067 | ||
ffbbdd21 | 1068 | |
8ae12a0d DB |
1069 | /** |
1070 | * spi_alloc_master - allocate SPI master controller | |
1071 | * @dev: the controller, possibly using the platform_bus | |
33e34dc6 | 1072 | * @size: how much zeroed driver-private data to allocate; the pointer to this |
49dce689 | 1073 | * memory is in the driver_data field of the returned device, |
0c868461 | 1074 | * accessible with spi_master_get_devdata(). |
33e34dc6 | 1075 | * Context: can sleep |
8ae12a0d DB |
1076 | * |
1077 | * This call is used only by SPI master controller drivers, which are the | |
1078 | * only ones directly touching chip registers. It's how they allocate | |
ba1a0513 | 1079 | * an spi_master structure, prior to calling spi_register_master(). |
8ae12a0d DB |
1080 | * |
1081 | * This must be called from context that can sleep. It returns the SPI | |
1082 | * master structure on success, else NULL. | |
1083 | * | |
1084 | * The caller is responsible for assigning the bus number and initializing | |
ba1a0513 | 1085 | * the master's methods before calling spi_register_master(); and (after errors |
eb4af0f5 UKK |
1086 | * adding the device) calling spi_master_put() and kfree() to prevent a memory |
1087 | * leak. | |
8ae12a0d | 1088 | */ |
e9d5a461 | 1089 | struct spi_master *spi_alloc_master(struct device *dev, unsigned size) |
8ae12a0d DB |
1090 | { |
1091 | struct spi_master *master; | |
1092 | ||
0c868461 DB |
1093 | if (!dev) |
1094 | return NULL; | |
1095 | ||
e94b1766 | 1096 | master = kzalloc(size + sizeof *master, GFP_KERNEL); |
8ae12a0d DB |
1097 | if (!master) |
1098 | return NULL; | |
1099 | ||
49dce689 | 1100 | device_initialize(&master->dev); |
1e8a52e1 GL |
1101 | master->bus_num = -1; |
1102 | master->num_chipselect = 1; | |
49dce689 TJ |
1103 | master->dev.class = &spi_master_class; |
1104 | master->dev.parent = get_device(dev); | |
0c868461 | 1105 | spi_master_set_devdata(master, &master[1]); |
8ae12a0d DB |
1106 | |
1107 | return master; | |
1108 | } | |
1109 | EXPORT_SYMBOL_GPL(spi_alloc_master); | |
1110 | ||
74317984 JCPV |
1111 | #ifdef CONFIG_OF |
1112 | static int of_spi_register_master(struct spi_master *master) | |
1113 | { | |
e80beb27 | 1114 | int nb, i, *cs; |
74317984 JCPV |
1115 | struct device_node *np = master->dev.of_node; |
1116 | ||
1117 | if (!np) | |
1118 | return 0; | |
1119 | ||
1120 | nb = of_gpio_named_count(np, "cs-gpios"); | |
e80beb27 | 1121 | master->num_chipselect = max(nb, (int)master->num_chipselect); |
74317984 | 1122 | |
8ec5d84e AL |
1123 | /* Return error only for an incorrectly formed cs-gpios property */ |
1124 | if (nb == 0 || nb == -ENOENT) | |
74317984 | 1125 | return 0; |
8ec5d84e AL |
1126 | else if (nb < 0) |
1127 | return nb; | |
74317984 JCPV |
1128 | |
1129 | cs = devm_kzalloc(&master->dev, | |
1130 | sizeof(int) * master->num_chipselect, | |
1131 | GFP_KERNEL); | |
1132 | master->cs_gpios = cs; | |
1133 | ||
1134 | if (!master->cs_gpios) | |
1135 | return -ENOMEM; | |
1136 | ||
0da83bb1 | 1137 | for (i = 0; i < master->num_chipselect; i++) |
446411e1 | 1138 | cs[i] = -ENOENT; |
74317984 JCPV |
1139 | |
1140 | for (i = 0; i < nb; i++) | |
1141 | cs[i] = of_get_named_gpio(np, "cs-gpios", i); | |
1142 | ||
1143 | return 0; | |
1144 | } | |
1145 | #else | |
1146 | static int of_spi_register_master(struct spi_master *master) | |
1147 | { | |
1148 | return 0; | |
1149 | } | |
1150 | #endif | |
1151 | ||
8ae12a0d DB |
1152 | /** |
1153 | * spi_register_master - register SPI master controller | |
1154 | * @master: initialized master, originally from spi_alloc_master() | |
33e34dc6 | 1155 | * Context: can sleep |
8ae12a0d DB |
1156 | * |
1157 | * SPI master controllers connect to their drivers using some non-SPI bus, | |
1158 | * such as the platform bus. The final stage of probe() in that code | |
1159 | * includes calling spi_register_master() to hook up to this SPI bus glue. | |
1160 | * | |
1161 | * SPI controllers use board specific (often SOC specific) bus numbers, | |
1162 | * and board-specific addressing for SPI devices combines those numbers | |
1163 | * with chip select numbers. Since SPI does not directly support dynamic | |
1164 | * device identification, boards need configuration tables telling which | |
1165 | * chip is at which address. | |
1166 | * | |
1167 | * This must be called from context that can sleep. It returns zero on | |
1168 | * success, else a negative error code (dropping the master's refcount). | |
0c868461 DB |
1169 | * After a successful return, the caller is responsible for calling |
1170 | * spi_unregister_master(). | |
8ae12a0d | 1171 | */ |
e9d5a461 | 1172 | int spi_register_master(struct spi_master *master) |
8ae12a0d | 1173 | { |
e44a45ae | 1174 | static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1); |
49dce689 | 1175 | struct device *dev = master->dev.parent; |
2b9603a0 | 1176 | struct boardinfo *bi; |
8ae12a0d DB |
1177 | int status = -ENODEV; |
1178 | int dynamic = 0; | |
1179 | ||
0c868461 DB |
1180 | if (!dev) |
1181 | return -ENODEV; | |
1182 | ||
74317984 JCPV |
1183 | status = of_spi_register_master(master); |
1184 | if (status) | |
1185 | return status; | |
1186 | ||
082c8cb4 DB |
1187 | /* even if it's just one always-selected device, there must |
1188 | * be at least one chipselect | |
1189 | */ | |
1190 | if (master->num_chipselect == 0) | |
1191 | return -EINVAL; | |
1192 | ||
bb29785e GL |
1193 | if ((master->bus_num < 0) && master->dev.of_node) |
1194 | master->bus_num = of_alias_get_id(master->dev.of_node, "spi"); | |
1195 | ||
8ae12a0d | 1196 | /* convention: dynamically assigned bus IDs count down from the max */ |
a020ed75 | 1197 | if (master->bus_num < 0) { |
082c8cb4 DB |
1198 | /* FIXME switch to an IDR based scheme, something like |
1199 | * I2C now uses, so we can't run out of "dynamic" IDs | |
1200 | */ | |
8ae12a0d | 1201 | master->bus_num = atomic_dec_return(&dyn_bus_id); |
b885244e | 1202 | dynamic = 1; |
8ae12a0d DB |
1203 | } |
1204 | ||
cf32b71e ES |
1205 | spin_lock_init(&master->bus_lock_spinlock); |
1206 | mutex_init(&master->bus_lock_mutex); | |
1207 | master->bus_lock_flag = 0; | |
1208 | ||
8ae12a0d DB |
1209 | /* register the device, then userspace will see it. |
1210 | * registration fails if the bus ID is in use. | |
1211 | */ | |
35f74fca | 1212 | dev_set_name(&master->dev, "spi%u", master->bus_num); |
49dce689 | 1213 | status = device_add(&master->dev); |
b885244e | 1214 | if (status < 0) |
8ae12a0d | 1215 | goto done; |
35f74fca | 1216 | dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev), |
8ae12a0d DB |
1217 | dynamic ? " (dynamic)" : ""); |
1218 | ||
ffbbdd21 LW |
1219 | /* If we're using a queued driver, start the queue */ |
1220 | if (master->transfer) | |
1221 | dev_info(dev, "master is unqueued, this is deprecated\n"); | |
1222 | else { | |
1223 | status = spi_master_initialize_queue(master); | |
1224 | if (status) { | |
e93b0724 | 1225 | device_del(&master->dev); |
ffbbdd21 LW |
1226 | goto done; |
1227 | } | |
1228 | } | |
1229 | ||
2b9603a0 FT |
1230 | mutex_lock(&board_lock); |
1231 | list_add_tail(&master->list, &spi_master_list); | |
1232 | list_for_each_entry(bi, &board_list, list) | |
1233 | spi_match_master_to_boardinfo(master, &bi->board_info); | |
1234 | mutex_unlock(&board_lock); | |
1235 | ||
64bee4d2 | 1236 | /* Register devices from the device tree and ACPI */ |
12b15e83 | 1237 | of_register_spi_devices(master); |
64bee4d2 | 1238 | acpi_register_spi_devices(master); |
8ae12a0d DB |
1239 | done: |
1240 | return status; | |
1241 | } | |
1242 | EXPORT_SYMBOL_GPL(spi_register_master); | |
1243 | ||
34860089 | 1244 | static int __unregister(struct device *dev, void *null) |
8ae12a0d | 1245 | { |
34860089 | 1246 | spi_unregister_device(to_spi_device(dev)); |
8ae12a0d DB |
1247 | return 0; |
1248 | } | |
1249 | ||
1250 | /** | |
1251 | * spi_unregister_master - unregister SPI master controller | |
1252 | * @master: the master being unregistered | |
33e34dc6 | 1253 | * Context: can sleep |
8ae12a0d DB |
1254 | * |
1255 | * This call is used only by SPI master controller drivers, which are the | |
1256 | * only ones directly touching chip registers. | |
1257 | * | |
1258 | * This must be called from context that can sleep. | |
1259 | */ | |
1260 | void spi_unregister_master(struct spi_master *master) | |
1261 | { | |
89fc9a1a JG |
1262 | int dummy; |
1263 | ||
ffbbdd21 LW |
1264 | if (master->queued) { |
1265 | if (spi_destroy_queue(master)) | |
1266 | dev_err(&master->dev, "queue remove failed\n"); | |
1267 | } | |
1268 | ||
2b9603a0 FT |
1269 | mutex_lock(&board_lock); |
1270 | list_del(&master->list); | |
1271 | mutex_unlock(&board_lock); | |
1272 | ||
97dbf37d | 1273 | dummy = device_for_each_child(&master->dev, NULL, __unregister); |
49dce689 | 1274 | device_unregister(&master->dev); |
8ae12a0d DB |
1275 | } |
1276 | EXPORT_SYMBOL_GPL(spi_unregister_master); | |
1277 | ||
ffbbdd21 LW |
1278 | int spi_master_suspend(struct spi_master *master) |
1279 | { | |
1280 | int ret; | |
1281 | ||
1282 | /* Basically no-ops for non-queued masters */ | |
1283 | if (!master->queued) | |
1284 | return 0; | |
1285 | ||
1286 | ret = spi_stop_queue(master); | |
1287 | if (ret) | |
1288 | dev_err(&master->dev, "queue stop failed\n"); | |
1289 | ||
1290 | return ret; | |
1291 | } | |
1292 | EXPORT_SYMBOL_GPL(spi_master_suspend); | |
1293 | ||
1294 | int spi_master_resume(struct spi_master *master) | |
1295 | { | |
1296 | int ret; | |
1297 | ||
1298 | if (!master->queued) | |
1299 | return 0; | |
1300 | ||
1301 | ret = spi_start_queue(master); | |
1302 | if (ret) | |
1303 | dev_err(&master->dev, "queue restart failed\n"); | |
1304 | ||
1305 | return ret; | |
1306 | } | |
1307 | EXPORT_SYMBOL_GPL(spi_master_resume); | |
1308 | ||
9f3b795a | 1309 | static int __spi_master_match(struct device *dev, const void *data) |
5ed2c832 DY |
1310 | { |
1311 | struct spi_master *m; | |
9f3b795a | 1312 | const u16 *bus_num = data; |
5ed2c832 DY |
1313 | |
1314 | m = container_of(dev, struct spi_master, dev); | |
1315 | return m->bus_num == *bus_num; | |
1316 | } | |
1317 | ||
8ae12a0d DB |
1318 | /** |
1319 | * spi_busnum_to_master - look up master associated with bus_num | |
1320 | * @bus_num: the master's bus number | |
33e34dc6 | 1321 | * Context: can sleep |
8ae12a0d DB |
1322 | * |
1323 | * This call may be used with devices that are registered after | |
1324 | * arch init time. It returns a refcounted pointer to the relevant | |
1325 | * spi_master (which the caller must release), or NULL if there is | |
1326 | * no such master registered. | |
1327 | */ | |
1328 | struct spi_master *spi_busnum_to_master(u16 bus_num) | |
1329 | { | |
49dce689 | 1330 | struct device *dev; |
1e9a51dc | 1331 | struct spi_master *master = NULL; |
5ed2c832 | 1332 | |
695794ae | 1333 | dev = class_find_device(&spi_master_class, NULL, &bus_num, |
5ed2c832 DY |
1334 | __spi_master_match); |
1335 | if (dev) | |
1336 | master = container_of(dev, struct spi_master, dev); | |
1337 | /* reference got in class_find_device */ | |
1e9a51dc | 1338 | return master; |
8ae12a0d DB |
1339 | } |
1340 | EXPORT_SYMBOL_GPL(spi_busnum_to_master); | |
1341 | ||
1342 | ||
1343 | /*-------------------------------------------------------------------------*/ | |
1344 | ||
7d077197 DB |
1345 | /* Core methods for SPI master protocol drivers. Some of the |
1346 | * other core methods are currently defined as inline functions. | |
1347 | */ | |
1348 | ||
1349 | /** | |
1350 | * spi_setup - setup SPI mode and clock rate | |
1351 | * @spi: the device whose settings are being modified | |
1352 | * Context: can sleep, and no requests are queued to the device | |
1353 | * | |
1354 | * SPI protocol drivers may need to update the transfer mode if the | |
1355 | * device doesn't work with its default. They may likewise need | |
1356 | * to update clock rates or word sizes from initial values. This function | |
1357 | * changes those settings, and must be called from a context that can sleep. | |
1358 | * Except for SPI_CS_HIGH, which takes effect immediately, the changes take | |
1359 | * effect the next time the device is selected and data is transferred to | |
1360 | * or from it. When this function returns, the spi device is deselected. | |
1361 | * | |
1362 | * Note that this call will fail if the protocol driver specifies an option | |
1363 | * that the underlying controller or its driver does not support. For | |
1364 | * example, not all hardware supports wire transfers using nine bit words, | |
1365 | * LSB-first wire encoding, or active-high chipselects. | |
1366 | */ | |
1367 | int spi_setup(struct spi_device *spi) | |
1368 | { | |
e7db06b5 | 1369 | unsigned bad_bits; |
caae070c | 1370 | int status = 0; |
7d077197 | 1371 | |
f477b7fb | 1372 | /* check mode to prevent that DUAL and QUAD set at the same time |
1373 | */ | |
1374 | if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) || | |
1375 | ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) { | |
1376 | dev_err(&spi->dev, | |
1377 | "setup: can not select dual and quad at the same time\n"); | |
1378 | return -EINVAL; | |
1379 | } | |
1380 | /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden | |
1381 | */ | |
1382 | if ((spi->mode & SPI_3WIRE) && (spi->mode & | |
1383 | (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD))) | |
1384 | return -EINVAL; | |
e7db06b5 DB |
1385 | /* help drivers fail *cleanly* when they need options |
1386 | * that aren't supported with their current master | |
1387 | */ | |
1388 | bad_bits = spi->mode & ~spi->master->mode_bits; | |
1389 | if (bad_bits) { | |
eb288a1f | 1390 | dev_err(&spi->dev, "setup: unsupported mode bits %x\n", |
e7db06b5 DB |
1391 | bad_bits); |
1392 | return -EINVAL; | |
1393 | } | |
1394 | ||
7d077197 DB |
1395 | if (!spi->bits_per_word) |
1396 | spi->bits_per_word = 8; | |
1397 | ||
caae070c LD |
1398 | if (spi->master->setup) |
1399 | status = spi->master->setup(spi); | |
7d077197 DB |
1400 | |
1401 | dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s" | |
1402 | "%u bits/w, %u Hz max --> %d\n", | |
1403 | (int) (spi->mode & (SPI_CPOL | SPI_CPHA)), | |
1404 | (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "", | |
1405 | (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "", | |
1406 | (spi->mode & SPI_3WIRE) ? "3wire, " : "", | |
1407 | (spi->mode & SPI_LOOP) ? "loopback, " : "", | |
1408 | spi->bits_per_word, spi->max_speed_hz, | |
1409 | status); | |
1410 | ||
1411 | return status; | |
1412 | } | |
1413 | EXPORT_SYMBOL_GPL(spi_setup); | |
1414 | ||
cf32b71e ES |
1415 | static int __spi_async(struct spi_device *spi, struct spi_message *message) |
1416 | { | |
1417 | struct spi_master *master = spi->master; | |
e6811d1d | 1418 | struct spi_transfer *xfer; |
cf32b71e | 1419 | |
24a0013a MB |
1420 | if (list_empty(&message->transfers)) |
1421 | return -EINVAL; | |
1422 | if (!message->complete) | |
1423 | return -EINVAL; | |
1424 | ||
cf32b71e ES |
1425 | /* Half-duplex links include original MicroWire, and ones with |
1426 | * only one data pin like SPI_3WIRE (switches direction) or where | |
1427 | * either MOSI or MISO is missing. They can also be caused by | |
1428 | * software limitations. | |
1429 | */ | |
1430 | if ((master->flags & SPI_MASTER_HALF_DUPLEX) | |
1431 | || (spi->mode & SPI_3WIRE)) { | |
cf32b71e ES |
1432 | unsigned flags = master->flags; |
1433 | ||
1434 | list_for_each_entry(xfer, &message->transfers, transfer_list) { | |
1435 | if (xfer->rx_buf && xfer->tx_buf) | |
1436 | return -EINVAL; | |
1437 | if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf) | |
1438 | return -EINVAL; | |
1439 | if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf) | |
1440 | return -EINVAL; | |
1441 | } | |
1442 | } | |
1443 | ||
e6811d1d | 1444 | /** |
059b8ffe LD |
1445 | * Set transfer bits_per_word and max speed as spi device default if |
1446 | * it is not set for this transfer. | |
f477b7fb | 1447 | * Set transfer tx_nbits and rx_nbits as single transfer default |
1448 | * (SPI_NBITS_SINGLE) if it is not set for this transfer. | |
e6811d1d LD |
1449 | */ |
1450 | list_for_each_entry(xfer, &message->transfers, transfer_list) { | |
078726ce | 1451 | message->frame_length += xfer->len; |
e6811d1d LD |
1452 | if (!xfer->bits_per_word) |
1453 | xfer->bits_per_word = spi->bits_per_word; | |
56ede94a | 1454 | if (!xfer->speed_hz) { |
059b8ffe | 1455 | xfer->speed_hz = spi->max_speed_hz; |
56ede94a GJ |
1456 | if (master->max_speed_hz && |
1457 | xfer->speed_hz > master->max_speed_hz) | |
1458 | xfer->speed_hz = master->max_speed_hz; | |
1459 | } | |
1460 | ||
543bb255 SW |
1461 | if (master->bits_per_word_mask) { |
1462 | /* Only 32 bits fit in the mask */ | |
1463 | if (xfer->bits_per_word > 32) | |
1464 | return -EINVAL; | |
1465 | if (!(master->bits_per_word_mask & | |
1466 | BIT(xfer->bits_per_word - 1))) | |
1467 | return -EINVAL; | |
1468 | } | |
a2fd4f9f MB |
1469 | |
1470 | if (xfer->speed_hz && master->min_speed_hz && | |
1471 | xfer->speed_hz < master->min_speed_hz) | |
1472 | return -EINVAL; | |
1473 | if (xfer->speed_hz && master->max_speed_hz && | |
1474 | xfer->speed_hz > master->max_speed_hz) | |
d5ee722a | 1475 | return -EINVAL; |
f477b7fb | 1476 | |
1477 | if (xfer->tx_buf && !xfer->tx_nbits) | |
1478 | xfer->tx_nbits = SPI_NBITS_SINGLE; | |
1479 | if (xfer->rx_buf && !xfer->rx_nbits) | |
1480 | xfer->rx_nbits = SPI_NBITS_SINGLE; | |
1481 | /* check transfer tx/rx_nbits: | |
1482 | * 1. keep the value is not out of single, dual and quad | |
1483 | * 2. keep tx/rx_nbits is contained by mode in spi_device | |
1484 | * 3. if SPI_3WIRE, tx/rx_nbits should be in single | |
1485 | */ | |
db90a441 SP |
1486 | if (xfer->tx_buf) { |
1487 | if (xfer->tx_nbits != SPI_NBITS_SINGLE && | |
1488 | xfer->tx_nbits != SPI_NBITS_DUAL && | |
1489 | xfer->tx_nbits != SPI_NBITS_QUAD) | |
1490 | return -EINVAL; | |
1491 | if ((xfer->tx_nbits == SPI_NBITS_DUAL) && | |
1492 | !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD))) | |
1493 | return -EINVAL; | |
1494 | if ((xfer->tx_nbits == SPI_NBITS_QUAD) && | |
1495 | !(spi->mode & SPI_TX_QUAD)) | |
1496 | return -EINVAL; | |
1497 | if ((spi->mode & SPI_3WIRE) && | |
1498 | (xfer->tx_nbits != SPI_NBITS_SINGLE)) | |
1499 | return -EINVAL; | |
1500 | } | |
f477b7fb | 1501 | /* check transfer rx_nbits */ |
db90a441 SP |
1502 | if (xfer->rx_buf) { |
1503 | if (xfer->rx_nbits != SPI_NBITS_SINGLE && | |
1504 | xfer->rx_nbits != SPI_NBITS_DUAL && | |
1505 | xfer->rx_nbits != SPI_NBITS_QUAD) | |
1506 | return -EINVAL; | |
1507 | if ((xfer->rx_nbits == SPI_NBITS_DUAL) && | |
1508 | !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD))) | |
1509 | return -EINVAL; | |
1510 | if ((xfer->rx_nbits == SPI_NBITS_QUAD) && | |
1511 | !(spi->mode & SPI_RX_QUAD)) | |
1512 | return -EINVAL; | |
1513 | if ((spi->mode & SPI_3WIRE) && | |
1514 | (xfer->rx_nbits != SPI_NBITS_SINGLE)) | |
1515 | return -EINVAL; | |
1516 | } | |
e6811d1d LD |
1517 | } |
1518 | ||
cf32b71e ES |
1519 | message->spi = spi; |
1520 | message->status = -EINPROGRESS; | |
1521 | return master->transfer(spi, message); | |
1522 | } | |
1523 | ||
568d0697 DB |
1524 | /** |
1525 | * spi_async - asynchronous SPI transfer | |
1526 | * @spi: device with which data will be exchanged | |
1527 | * @message: describes the data transfers, including completion callback | |
1528 | * Context: any (irqs may be blocked, etc) | |
1529 | * | |
1530 | * This call may be used in_irq and other contexts which can't sleep, | |
1531 | * as well as from task contexts which can sleep. | |
1532 | * | |
1533 | * The completion callback is invoked in a context which can't sleep. | |
1534 | * Before that invocation, the value of message->status is undefined. | |
1535 | * When the callback is issued, message->status holds either zero (to | |
1536 | * indicate complete success) or a negative error code. After that | |
1537 | * callback returns, the driver which issued the transfer request may | |
1538 | * deallocate the associated memory; it's no longer in use by any SPI | |
1539 | * core or controller driver code. | |
1540 | * | |
1541 | * Note that although all messages to a spi_device are handled in | |
1542 | * FIFO order, messages may go to different devices in other orders. | |
1543 | * Some device might be higher priority, or have various "hard" access | |
1544 | * time requirements, for example. | |
1545 | * | |
1546 | * On detection of any fault during the transfer, processing of | |
1547 | * the entire message is aborted, and the device is deselected. | |
1548 | * Until returning from the associated message completion callback, | |
1549 | * no other spi_message queued to that device will be processed. | |
1550 | * (This rule applies equally to all the synchronous transfer calls, | |
1551 | * which are wrappers around this core asynchronous primitive.) | |
1552 | */ | |
1553 | int spi_async(struct spi_device *spi, struct spi_message *message) | |
1554 | { | |
1555 | struct spi_master *master = spi->master; | |
cf32b71e ES |
1556 | int ret; |
1557 | unsigned long flags; | |
568d0697 | 1558 | |
cf32b71e | 1559 | spin_lock_irqsave(&master->bus_lock_spinlock, flags); |
568d0697 | 1560 | |
cf32b71e ES |
1561 | if (master->bus_lock_flag) |
1562 | ret = -EBUSY; | |
1563 | else | |
1564 | ret = __spi_async(spi, message); | |
568d0697 | 1565 | |
cf32b71e ES |
1566 | spin_unlock_irqrestore(&master->bus_lock_spinlock, flags); |
1567 | ||
1568 | return ret; | |
568d0697 DB |
1569 | } |
1570 | EXPORT_SYMBOL_GPL(spi_async); | |
1571 | ||
cf32b71e ES |
1572 | /** |
1573 | * spi_async_locked - version of spi_async with exclusive bus usage | |
1574 | * @spi: device with which data will be exchanged | |
1575 | * @message: describes the data transfers, including completion callback | |
1576 | * Context: any (irqs may be blocked, etc) | |
1577 | * | |
1578 | * This call may be used in_irq and other contexts which can't sleep, | |
1579 | * as well as from task contexts which can sleep. | |
1580 | * | |
1581 | * The completion callback is invoked in a context which can't sleep. | |
1582 | * Before that invocation, the value of message->status is undefined. | |
1583 | * When the callback is issued, message->status holds either zero (to | |
1584 | * indicate complete success) or a negative error code. After that | |
1585 | * callback returns, the driver which issued the transfer request may | |
1586 | * deallocate the associated memory; it's no longer in use by any SPI | |
1587 | * core or controller driver code. | |
1588 | * | |
1589 | * Note that although all messages to a spi_device are handled in | |
1590 | * FIFO order, messages may go to different devices in other orders. | |
1591 | * Some device might be higher priority, or have various "hard" access | |
1592 | * time requirements, for example. | |
1593 | * | |
1594 | * On detection of any fault during the transfer, processing of | |
1595 | * the entire message is aborted, and the device is deselected. | |
1596 | * Until returning from the associated message completion callback, | |
1597 | * no other spi_message queued to that device will be processed. | |
1598 | * (This rule applies equally to all the synchronous transfer calls, | |
1599 | * which are wrappers around this core asynchronous primitive.) | |
1600 | */ | |
1601 | int spi_async_locked(struct spi_device *spi, struct spi_message *message) | |
1602 | { | |
1603 | struct spi_master *master = spi->master; | |
1604 | int ret; | |
1605 | unsigned long flags; | |
1606 | ||
1607 | spin_lock_irqsave(&master->bus_lock_spinlock, flags); | |
1608 | ||
1609 | ret = __spi_async(spi, message); | |
1610 | ||
1611 | spin_unlock_irqrestore(&master->bus_lock_spinlock, flags); | |
1612 | ||
1613 | return ret; | |
1614 | ||
1615 | } | |
1616 | EXPORT_SYMBOL_GPL(spi_async_locked); | |
1617 | ||
7d077197 DB |
1618 | |
1619 | /*-------------------------------------------------------------------------*/ | |
1620 | ||
1621 | /* Utility methods for SPI master protocol drivers, layered on | |
1622 | * top of the core. Some other utility methods are defined as | |
1623 | * inline functions. | |
1624 | */ | |
1625 | ||
5d870c8e AM |
1626 | static void spi_complete(void *arg) |
1627 | { | |
1628 | complete(arg); | |
1629 | } | |
1630 | ||
cf32b71e ES |
1631 | static int __spi_sync(struct spi_device *spi, struct spi_message *message, |
1632 | int bus_locked) | |
1633 | { | |
1634 | DECLARE_COMPLETION_ONSTACK(done); | |
1635 | int status; | |
1636 | struct spi_master *master = spi->master; | |
1637 | ||
1638 | message->complete = spi_complete; | |
1639 | message->context = &done; | |
1640 | ||
1641 | if (!bus_locked) | |
1642 | mutex_lock(&master->bus_lock_mutex); | |
1643 | ||
1644 | status = spi_async_locked(spi, message); | |
1645 | ||
1646 | if (!bus_locked) | |
1647 | mutex_unlock(&master->bus_lock_mutex); | |
1648 | ||
1649 | if (status == 0) { | |
1650 | wait_for_completion(&done); | |
1651 | status = message->status; | |
1652 | } | |
1653 | message->context = NULL; | |
1654 | return status; | |
1655 | } | |
1656 | ||
8ae12a0d DB |
1657 | /** |
1658 | * spi_sync - blocking/synchronous SPI data transfers | |
1659 | * @spi: device with which data will be exchanged | |
1660 | * @message: describes the data transfers | |
33e34dc6 | 1661 | * Context: can sleep |
8ae12a0d DB |
1662 | * |
1663 | * This call may only be used from a context that may sleep. The sleep | |
1664 | * is non-interruptible, and has no timeout. Low-overhead controller | |
1665 | * drivers may DMA directly into and out of the message buffers. | |
1666 | * | |
1667 | * Note that the SPI device's chip select is active during the message, | |
1668 | * and then is normally disabled between messages. Drivers for some | |
1669 | * frequently-used devices may want to minimize costs of selecting a chip, | |
1670 | * by leaving it selected in anticipation that the next message will go | |
1671 | * to the same chip. (That may increase power usage.) | |
1672 | * | |
0c868461 DB |
1673 | * Also, the caller is guaranteeing that the memory associated with the |
1674 | * message will not be freed before this call returns. | |
1675 | * | |
9b938b74 | 1676 | * It returns zero on success, else a negative error code. |
8ae12a0d DB |
1677 | */ |
1678 | int spi_sync(struct spi_device *spi, struct spi_message *message) | |
1679 | { | |
cf32b71e | 1680 | return __spi_sync(spi, message, 0); |
8ae12a0d DB |
1681 | } |
1682 | EXPORT_SYMBOL_GPL(spi_sync); | |
1683 | ||
cf32b71e ES |
1684 | /** |
1685 | * spi_sync_locked - version of spi_sync with exclusive bus usage | |
1686 | * @spi: device with which data will be exchanged | |
1687 | * @message: describes the data transfers | |
1688 | * Context: can sleep | |
1689 | * | |
1690 | * This call may only be used from a context that may sleep. The sleep | |
1691 | * is non-interruptible, and has no timeout. Low-overhead controller | |
1692 | * drivers may DMA directly into and out of the message buffers. | |
1693 | * | |
1694 | * This call should be used by drivers that require exclusive access to the | |
25985edc | 1695 | * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must |
cf32b71e ES |
1696 | * be released by a spi_bus_unlock call when the exclusive access is over. |
1697 | * | |
1698 | * It returns zero on success, else a negative error code. | |
1699 | */ | |
1700 | int spi_sync_locked(struct spi_device *spi, struct spi_message *message) | |
1701 | { | |
1702 | return __spi_sync(spi, message, 1); | |
1703 | } | |
1704 | EXPORT_SYMBOL_GPL(spi_sync_locked); | |
1705 | ||
1706 | /** | |
1707 | * spi_bus_lock - obtain a lock for exclusive SPI bus usage | |
1708 | * @master: SPI bus master that should be locked for exclusive bus access | |
1709 | * Context: can sleep | |
1710 | * | |
1711 | * This call may only be used from a context that may sleep. The sleep | |
1712 | * is non-interruptible, and has no timeout. | |
1713 | * | |
1714 | * This call should be used by drivers that require exclusive access to the | |
1715 | * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the | |
1716 | * exclusive access is over. Data transfer must be done by spi_sync_locked | |
1717 | * and spi_async_locked calls when the SPI bus lock is held. | |
1718 | * | |
1719 | * It returns zero on success, else a negative error code. | |
1720 | */ | |
1721 | int spi_bus_lock(struct spi_master *master) | |
1722 | { | |
1723 | unsigned long flags; | |
1724 | ||
1725 | mutex_lock(&master->bus_lock_mutex); | |
1726 | ||
1727 | spin_lock_irqsave(&master->bus_lock_spinlock, flags); | |
1728 | master->bus_lock_flag = 1; | |
1729 | spin_unlock_irqrestore(&master->bus_lock_spinlock, flags); | |
1730 | ||
1731 | /* mutex remains locked until spi_bus_unlock is called */ | |
1732 | ||
1733 | return 0; | |
1734 | } | |
1735 | EXPORT_SYMBOL_GPL(spi_bus_lock); | |
1736 | ||
1737 | /** | |
1738 | * spi_bus_unlock - release the lock for exclusive SPI bus usage | |
1739 | * @master: SPI bus master that was locked for exclusive bus access | |
1740 | * Context: can sleep | |
1741 | * | |
1742 | * This call may only be used from a context that may sleep. The sleep | |
1743 | * is non-interruptible, and has no timeout. | |
1744 | * | |
1745 | * This call releases an SPI bus lock previously obtained by an spi_bus_lock | |
1746 | * call. | |
1747 | * | |
1748 | * It returns zero on success, else a negative error code. | |
1749 | */ | |
1750 | int spi_bus_unlock(struct spi_master *master) | |
1751 | { | |
1752 | master->bus_lock_flag = 0; | |
1753 | ||
1754 | mutex_unlock(&master->bus_lock_mutex); | |
1755 | ||
1756 | return 0; | |
1757 | } | |
1758 | EXPORT_SYMBOL_GPL(spi_bus_unlock); | |
1759 | ||
a9948b61 DB |
1760 | /* portable code must never pass more than 32 bytes */ |
1761 | #define SPI_BUFSIZ max(32,SMP_CACHE_BYTES) | |
8ae12a0d DB |
1762 | |
1763 | static u8 *buf; | |
1764 | ||
1765 | /** | |
1766 | * spi_write_then_read - SPI synchronous write followed by read | |
1767 | * @spi: device with which data will be exchanged | |
1768 | * @txbuf: data to be written (need not be dma-safe) | |
1769 | * @n_tx: size of txbuf, in bytes | |
27570497 JP |
1770 | * @rxbuf: buffer into which data will be read (need not be dma-safe) |
1771 | * @n_rx: size of rxbuf, in bytes | |
33e34dc6 | 1772 | * Context: can sleep |
8ae12a0d DB |
1773 | * |
1774 | * This performs a half duplex MicroWire style transaction with the | |
1775 | * device, sending txbuf and then reading rxbuf. The return value | |
1776 | * is zero for success, else a negative errno status code. | |
b885244e | 1777 | * This call may only be used from a context that may sleep. |
8ae12a0d | 1778 | * |
0c868461 | 1779 | * Parameters to this routine are always copied using a small buffer; |
33e34dc6 DB |
1780 | * portable code should never use this for more than 32 bytes. |
1781 | * Performance-sensitive or bulk transfer code should instead use | |
0c868461 | 1782 | * spi_{async,sync}() calls with dma-safe buffers. |
8ae12a0d DB |
1783 | */ |
1784 | int spi_write_then_read(struct spi_device *spi, | |
0c4a1590 MB |
1785 | const void *txbuf, unsigned n_tx, |
1786 | void *rxbuf, unsigned n_rx) | |
8ae12a0d | 1787 | { |
068f4070 | 1788 | static DEFINE_MUTEX(lock); |
8ae12a0d DB |
1789 | |
1790 | int status; | |
1791 | struct spi_message message; | |
bdff549e | 1792 | struct spi_transfer x[2]; |
8ae12a0d DB |
1793 | u8 *local_buf; |
1794 | ||
b3a223ee MB |
1795 | /* Use preallocated DMA-safe buffer if we can. We can't avoid |
1796 | * copying here, (as a pure convenience thing), but we can | |
1797 | * keep heap costs out of the hot path unless someone else is | |
1798 | * using the pre-allocated buffer or the transfer is too large. | |
8ae12a0d | 1799 | */ |
b3a223ee | 1800 | if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) { |
2cd94c8a MB |
1801 | local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx), |
1802 | GFP_KERNEL | GFP_DMA); | |
b3a223ee MB |
1803 | if (!local_buf) |
1804 | return -ENOMEM; | |
1805 | } else { | |
1806 | local_buf = buf; | |
1807 | } | |
8ae12a0d | 1808 | |
8275c642 | 1809 | spi_message_init(&message); |
bdff549e DB |
1810 | memset(x, 0, sizeof x); |
1811 | if (n_tx) { | |
1812 | x[0].len = n_tx; | |
1813 | spi_message_add_tail(&x[0], &message); | |
1814 | } | |
1815 | if (n_rx) { | |
1816 | x[1].len = n_rx; | |
1817 | spi_message_add_tail(&x[1], &message); | |
1818 | } | |
8275c642 | 1819 | |
8ae12a0d | 1820 | memcpy(local_buf, txbuf, n_tx); |
bdff549e DB |
1821 | x[0].tx_buf = local_buf; |
1822 | x[1].rx_buf = local_buf + n_tx; | |
8ae12a0d DB |
1823 | |
1824 | /* do the i/o */ | |
8ae12a0d | 1825 | status = spi_sync(spi, &message); |
9b938b74 | 1826 | if (status == 0) |
bdff549e | 1827 | memcpy(rxbuf, x[1].rx_buf, n_rx); |
8ae12a0d | 1828 | |
bdff549e | 1829 | if (x[0].tx_buf == buf) |
068f4070 | 1830 | mutex_unlock(&lock); |
8ae12a0d DB |
1831 | else |
1832 | kfree(local_buf); | |
1833 | ||
1834 | return status; | |
1835 | } | |
1836 | EXPORT_SYMBOL_GPL(spi_write_then_read); | |
1837 | ||
1838 | /*-------------------------------------------------------------------------*/ | |
1839 | ||
1840 | static int __init spi_init(void) | |
1841 | { | |
b885244e DB |
1842 | int status; |
1843 | ||
e94b1766 | 1844 | buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL); |
b885244e DB |
1845 | if (!buf) { |
1846 | status = -ENOMEM; | |
1847 | goto err0; | |
1848 | } | |
1849 | ||
1850 | status = bus_register(&spi_bus_type); | |
1851 | if (status < 0) | |
1852 | goto err1; | |
8ae12a0d | 1853 | |
b885244e DB |
1854 | status = class_register(&spi_master_class); |
1855 | if (status < 0) | |
1856 | goto err2; | |
8ae12a0d | 1857 | return 0; |
b885244e DB |
1858 | |
1859 | err2: | |
1860 | bus_unregister(&spi_bus_type); | |
1861 | err1: | |
1862 | kfree(buf); | |
1863 | buf = NULL; | |
1864 | err0: | |
1865 | return status; | |
8ae12a0d | 1866 | } |
b885244e | 1867 | |
8ae12a0d DB |
1868 | /* board_info is normally registered in arch_initcall(), |
1869 | * but even essential drivers wait till later | |
b885244e DB |
1870 | * |
1871 | * REVISIT only boardinfo really needs static linking. the rest (device and | |
1872 | * driver registration) _could_ be dynamically linked (modular) ... costs | |
1873 | * include needing to have boardinfo data structures be much more public. | |
8ae12a0d | 1874 | */ |
673c0c00 | 1875 | postcore_initcall(spi_init); |
8ae12a0d | 1876 |