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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 | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation; either version 2 of the License, or | |
9 | * (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License | |
17 | * along with this program; if not, write to the Free Software | |
18 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
19 | */ | |
20 | ||
8ae12a0d DB |
21 | #include <linux/kernel.h> |
22 | #include <linux/device.h> | |
23 | #include <linux/init.h> | |
24 | #include <linux/cache.h> | |
94040828 | 25 | #include <linux/mutex.h> |
2b7a32f7 | 26 | #include <linux/of_device.h> |
5a0e3ad6 | 27 | #include <linux/slab.h> |
e0626e38 | 28 | #include <linux/mod_devicetable.h> |
8ae12a0d | 29 | #include <linux/spi/spi.h> |
12b15e83 | 30 | #include <linux/of_spi.h> |
3ae22e8c | 31 | #include <linux/pm_runtime.h> |
025ed130 | 32 | #include <linux/export.h> |
8ae12a0d | 33 | |
8ae12a0d DB |
34 | static void spidev_release(struct device *dev) |
35 | { | |
0ffa0285 | 36 | struct spi_device *spi = to_spi_device(dev); |
8ae12a0d DB |
37 | |
38 | /* spi masters may cleanup for released devices */ | |
39 | if (spi->master->cleanup) | |
40 | spi->master->cleanup(spi); | |
41 | ||
0c868461 | 42 | spi_master_put(spi->master); |
07a389fe | 43 | kfree(spi); |
8ae12a0d DB |
44 | } |
45 | ||
46 | static ssize_t | |
47 | modalias_show(struct device *dev, struct device_attribute *a, char *buf) | |
48 | { | |
49 | const struct spi_device *spi = to_spi_device(dev); | |
50 | ||
35f74fca | 51 | return sprintf(buf, "%s\n", spi->modalias); |
8ae12a0d DB |
52 | } |
53 | ||
54 | static struct device_attribute spi_dev_attrs[] = { | |
55 | __ATTR_RO(modalias), | |
56 | __ATTR_NULL, | |
57 | }; | |
58 | ||
59 | /* modalias support makes "modprobe $MODALIAS" new-style hotplug work, | |
60 | * and the sysfs version makes coldplug work too. | |
61 | */ | |
62 | ||
75368bf6 AV |
63 | static const struct spi_device_id *spi_match_id(const struct spi_device_id *id, |
64 | const struct spi_device *sdev) | |
65 | { | |
66 | while (id->name[0]) { | |
67 | if (!strcmp(sdev->modalias, id->name)) | |
68 | return id; | |
69 | id++; | |
70 | } | |
71 | return NULL; | |
72 | } | |
73 | ||
74 | const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev) | |
75 | { | |
76 | const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver); | |
77 | ||
78 | return spi_match_id(sdrv->id_table, sdev); | |
79 | } | |
80 | EXPORT_SYMBOL_GPL(spi_get_device_id); | |
81 | ||
8ae12a0d DB |
82 | static int spi_match_device(struct device *dev, struct device_driver *drv) |
83 | { | |
84 | const struct spi_device *spi = to_spi_device(dev); | |
75368bf6 AV |
85 | const struct spi_driver *sdrv = to_spi_driver(drv); |
86 | ||
2b7a32f7 SA |
87 | /* Attempt an OF style match */ |
88 | if (of_driver_match_device(dev, drv)) | |
89 | return 1; | |
90 | ||
75368bf6 AV |
91 | if (sdrv->id_table) |
92 | return !!spi_match_id(sdrv->id_table, spi); | |
8ae12a0d | 93 | |
35f74fca | 94 | return strcmp(spi->modalias, drv->name) == 0; |
8ae12a0d DB |
95 | } |
96 | ||
7eff2e7a | 97 | static int spi_uevent(struct device *dev, struct kobj_uevent_env *env) |
8ae12a0d DB |
98 | { |
99 | const struct spi_device *spi = to_spi_device(dev); | |
100 | ||
e0626e38 | 101 | add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias); |
8ae12a0d DB |
102 | return 0; |
103 | } | |
104 | ||
3ae22e8c MB |
105 | #ifdef CONFIG_PM_SLEEP |
106 | static int spi_legacy_suspend(struct device *dev, pm_message_t message) | |
8ae12a0d | 107 | { |
3c72426f | 108 | int value = 0; |
b885244e | 109 | struct spi_driver *drv = to_spi_driver(dev->driver); |
8ae12a0d | 110 | |
8ae12a0d | 111 | /* suspend will stop irqs and dma; no more i/o */ |
3c72426f DB |
112 | if (drv) { |
113 | if (drv->suspend) | |
114 | value = drv->suspend(to_spi_device(dev), message); | |
115 | else | |
116 | dev_dbg(dev, "... can't suspend\n"); | |
117 | } | |
8ae12a0d DB |
118 | return value; |
119 | } | |
120 | ||
3ae22e8c | 121 | static int spi_legacy_resume(struct device *dev) |
8ae12a0d | 122 | { |
3c72426f | 123 | int value = 0; |
b885244e | 124 | struct spi_driver *drv = to_spi_driver(dev->driver); |
8ae12a0d | 125 | |
8ae12a0d | 126 | /* resume may restart the i/o queue */ |
3c72426f DB |
127 | if (drv) { |
128 | if (drv->resume) | |
129 | value = drv->resume(to_spi_device(dev)); | |
130 | else | |
131 | dev_dbg(dev, "... can't resume\n"); | |
132 | } | |
8ae12a0d DB |
133 | return value; |
134 | } | |
135 | ||
3ae22e8c MB |
136 | static int spi_pm_suspend(struct device *dev) |
137 | { | |
138 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
139 | ||
140 | if (pm) | |
141 | return pm_generic_suspend(dev); | |
142 | else | |
143 | return spi_legacy_suspend(dev, PMSG_SUSPEND); | |
144 | } | |
145 | ||
146 | static int spi_pm_resume(struct device *dev) | |
147 | { | |
148 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
149 | ||
150 | if (pm) | |
151 | return pm_generic_resume(dev); | |
152 | else | |
153 | return spi_legacy_resume(dev); | |
154 | } | |
155 | ||
156 | static int spi_pm_freeze(struct device *dev) | |
157 | { | |
158 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
159 | ||
160 | if (pm) | |
161 | return pm_generic_freeze(dev); | |
162 | else | |
163 | return spi_legacy_suspend(dev, PMSG_FREEZE); | |
164 | } | |
165 | ||
166 | static int spi_pm_thaw(struct device *dev) | |
167 | { | |
168 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
169 | ||
170 | if (pm) | |
171 | return pm_generic_thaw(dev); | |
172 | else | |
173 | return spi_legacy_resume(dev); | |
174 | } | |
175 | ||
176 | static int spi_pm_poweroff(struct device *dev) | |
177 | { | |
178 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
179 | ||
180 | if (pm) | |
181 | return pm_generic_poweroff(dev); | |
182 | else | |
183 | return spi_legacy_suspend(dev, PMSG_HIBERNATE); | |
184 | } | |
185 | ||
186 | static int spi_pm_restore(struct device *dev) | |
187 | { | |
188 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
189 | ||
190 | if (pm) | |
191 | return pm_generic_restore(dev); | |
192 | else | |
193 | return spi_legacy_resume(dev); | |
194 | } | |
8ae12a0d | 195 | #else |
3ae22e8c MB |
196 | #define spi_pm_suspend NULL |
197 | #define spi_pm_resume NULL | |
198 | #define spi_pm_freeze NULL | |
199 | #define spi_pm_thaw NULL | |
200 | #define spi_pm_poweroff NULL | |
201 | #define spi_pm_restore NULL | |
8ae12a0d DB |
202 | #endif |
203 | ||
3ae22e8c MB |
204 | static const struct dev_pm_ops spi_pm = { |
205 | .suspend = spi_pm_suspend, | |
206 | .resume = spi_pm_resume, | |
207 | .freeze = spi_pm_freeze, | |
208 | .thaw = spi_pm_thaw, | |
209 | .poweroff = spi_pm_poweroff, | |
210 | .restore = spi_pm_restore, | |
211 | SET_RUNTIME_PM_OPS( | |
212 | pm_generic_runtime_suspend, | |
213 | pm_generic_runtime_resume, | |
214 | pm_generic_runtime_idle | |
215 | ) | |
216 | }; | |
217 | ||
8ae12a0d DB |
218 | struct bus_type spi_bus_type = { |
219 | .name = "spi", | |
220 | .dev_attrs = spi_dev_attrs, | |
221 | .match = spi_match_device, | |
222 | .uevent = spi_uevent, | |
3ae22e8c | 223 | .pm = &spi_pm, |
8ae12a0d DB |
224 | }; |
225 | EXPORT_SYMBOL_GPL(spi_bus_type); | |
226 | ||
b885244e DB |
227 | |
228 | static int spi_drv_probe(struct device *dev) | |
229 | { | |
230 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); | |
231 | ||
232 | return sdrv->probe(to_spi_device(dev)); | |
233 | } | |
234 | ||
235 | static int spi_drv_remove(struct device *dev) | |
236 | { | |
237 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); | |
238 | ||
239 | return sdrv->remove(to_spi_device(dev)); | |
240 | } | |
241 | ||
242 | static void spi_drv_shutdown(struct device *dev) | |
243 | { | |
244 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); | |
245 | ||
246 | sdrv->shutdown(to_spi_device(dev)); | |
247 | } | |
248 | ||
33e34dc6 DB |
249 | /** |
250 | * spi_register_driver - register a SPI driver | |
251 | * @sdrv: the driver to register | |
252 | * Context: can sleep | |
253 | */ | |
b885244e DB |
254 | int spi_register_driver(struct spi_driver *sdrv) |
255 | { | |
256 | sdrv->driver.bus = &spi_bus_type; | |
257 | if (sdrv->probe) | |
258 | sdrv->driver.probe = spi_drv_probe; | |
259 | if (sdrv->remove) | |
260 | sdrv->driver.remove = spi_drv_remove; | |
261 | if (sdrv->shutdown) | |
262 | sdrv->driver.shutdown = spi_drv_shutdown; | |
263 | return driver_register(&sdrv->driver); | |
264 | } | |
265 | EXPORT_SYMBOL_GPL(spi_register_driver); | |
266 | ||
8ae12a0d DB |
267 | /*-------------------------------------------------------------------------*/ |
268 | ||
269 | /* SPI devices should normally not be created by SPI device drivers; that | |
270 | * would make them board-specific. Similarly with SPI master drivers. | |
271 | * Device registration normally goes into like arch/.../mach.../board-YYY.c | |
272 | * with other readonly (flashable) information about mainboard devices. | |
273 | */ | |
274 | ||
275 | struct boardinfo { | |
276 | struct list_head list; | |
2b9603a0 | 277 | struct spi_board_info board_info; |
8ae12a0d DB |
278 | }; |
279 | ||
280 | static LIST_HEAD(board_list); | |
2b9603a0 FT |
281 | static LIST_HEAD(spi_master_list); |
282 | ||
283 | /* | |
284 | * Used to protect add/del opertion for board_info list and | |
285 | * spi_master list, and their matching process | |
286 | */ | |
94040828 | 287 | static DEFINE_MUTEX(board_lock); |
8ae12a0d | 288 | |
dc87c98e GL |
289 | /** |
290 | * spi_alloc_device - Allocate a new SPI device | |
291 | * @master: Controller to which device is connected | |
292 | * Context: can sleep | |
293 | * | |
294 | * Allows a driver to allocate and initialize a spi_device without | |
295 | * registering it immediately. This allows a driver to directly | |
296 | * fill the spi_device with device parameters before calling | |
297 | * spi_add_device() on it. | |
298 | * | |
299 | * Caller is responsible to call spi_add_device() on the returned | |
300 | * spi_device structure to add it to the SPI master. If the caller | |
301 | * needs to discard the spi_device without adding it, then it should | |
302 | * call spi_dev_put() on it. | |
303 | * | |
304 | * Returns a pointer to the new device, or NULL. | |
305 | */ | |
306 | struct spi_device *spi_alloc_device(struct spi_master *master) | |
307 | { | |
308 | struct spi_device *spi; | |
309 | struct device *dev = master->dev.parent; | |
310 | ||
311 | if (!spi_master_get(master)) | |
312 | return NULL; | |
313 | ||
314 | spi = kzalloc(sizeof *spi, GFP_KERNEL); | |
315 | if (!spi) { | |
316 | dev_err(dev, "cannot alloc spi_device\n"); | |
317 | spi_master_put(master); | |
318 | return NULL; | |
319 | } | |
320 | ||
321 | spi->master = master; | |
178db7d3 | 322 | spi->dev.parent = &master->dev; |
dc87c98e GL |
323 | spi->dev.bus = &spi_bus_type; |
324 | spi->dev.release = spidev_release; | |
325 | device_initialize(&spi->dev); | |
326 | return spi; | |
327 | } | |
328 | EXPORT_SYMBOL_GPL(spi_alloc_device); | |
329 | ||
330 | /** | |
331 | * spi_add_device - Add spi_device allocated with spi_alloc_device | |
332 | * @spi: spi_device to register | |
333 | * | |
334 | * Companion function to spi_alloc_device. Devices allocated with | |
335 | * spi_alloc_device can be added onto the spi bus with this function. | |
336 | * | |
e48880e0 | 337 | * Returns 0 on success; negative errno on failure |
dc87c98e GL |
338 | */ |
339 | int spi_add_device(struct spi_device *spi) | |
340 | { | |
e48880e0 | 341 | static DEFINE_MUTEX(spi_add_lock); |
dc87c98e | 342 | struct device *dev = spi->master->dev.parent; |
8ec130a0 | 343 | struct device *d; |
dc87c98e GL |
344 | int status; |
345 | ||
346 | /* Chipselects are numbered 0..max; validate. */ | |
347 | if (spi->chip_select >= spi->master->num_chipselect) { | |
348 | dev_err(dev, "cs%d >= max %d\n", | |
349 | spi->chip_select, | |
350 | spi->master->num_chipselect); | |
351 | return -EINVAL; | |
352 | } | |
353 | ||
354 | /* Set the bus ID string */ | |
35f74fca | 355 | dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev), |
dc87c98e GL |
356 | spi->chip_select); |
357 | ||
e48880e0 DB |
358 | |
359 | /* We need to make sure there's no other device with this | |
360 | * chipselect **BEFORE** we call setup(), else we'll trash | |
361 | * its configuration. Lock against concurrent add() calls. | |
362 | */ | |
363 | mutex_lock(&spi_add_lock); | |
364 | ||
8ec130a0 RT |
365 | d = bus_find_device_by_name(&spi_bus_type, NULL, dev_name(&spi->dev)); |
366 | if (d != NULL) { | |
e48880e0 DB |
367 | dev_err(dev, "chipselect %d already in use\n", |
368 | spi->chip_select); | |
8ec130a0 | 369 | put_device(d); |
e48880e0 DB |
370 | status = -EBUSY; |
371 | goto done; | |
372 | } | |
373 | ||
374 | /* Drivers may modify this initial i/o setup, but will | |
375 | * normally rely on the device being setup. Devices | |
376 | * using SPI_CS_HIGH can't coexist well otherwise... | |
377 | */ | |
7d077197 | 378 | status = spi_setup(spi); |
dc87c98e | 379 | if (status < 0) { |
eb288a1f LW |
380 | dev_err(dev, "can't setup %s, status %d\n", |
381 | dev_name(&spi->dev), status); | |
e48880e0 | 382 | goto done; |
dc87c98e GL |
383 | } |
384 | ||
e48880e0 | 385 | /* Device may be bound to an active driver when this returns */ |
dc87c98e | 386 | status = device_add(&spi->dev); |
e48880e0 | 387 | if (status < 0) |
eb288a1f LW |
388 | dev_err(dev, "can't add %s, status %d\n", |
389 | dev_name(&spi->dev), status); | |
e48880e0 | 390 | else |
35f74fca | 391 | dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev)); |
dc87c98e | 392 | |
e48880e0 DB |
393 | done: |
394 | mutex_unlock(&spi_add_lock); | |
395 | return status; | |
dc87c98e GL |
396 | } |
397 | EXPORT_SYMBOL_GPL(spi_add_device); | |
8ae12a0d | 398 | |
33e34dc6 DB |
399 | /** |
400 | * spi_new_device - instantiate one new SPI device | |
401 | * @master: Controller to which device is connected | |
402 | * @chip: Describes the SPI device | |
403 | * Context: can sleep | |
404 | * | |
405 | * On typical mainboards, this is purely internal; and it's not needed | |
8ae12a0d DB |
406 | * after board init creates the hard-wired devices. Some development |
407 | * platforms may not be able to use spi_register_board_info though, and | |
408 | * this is exported so that for example a USB or parport based adapter | |
409 | * driver could add devices (which it would learn about out-of-band). | |
082c8cb4 DB |
410 | * |
411 | * Returns the new device, or NULL. | |
8ae12a0d | 412 | */ |
e9d5a461 AB |
413 | struct spi_device *spi_new_device(struct spi_master *master, |
414 | struct spi_board_info *chip) | |
8ae12a0d DB |
415 | { |
416 | struct spi_device *proxy; | |
8ae12a0d DB |
417 | int status; |
418 | ||
082c8cb4 DB |
419 | /* NOTE: caller did any chip->bus_num checks necessary. |
420 | * | |
421 | * Also, unless we change the return value convention to use | |
422 | * error-or-pointer (not NULL-or-pointer), troubleshootability | |
423 | * suggests syslogged diagnostics are best here (ugh). | |
424 | */ | |
425 | ||
dc87c98e GL |
426 | proxy = spi_alloc_device(master); |
427 | if (!proxy) | |
8ae12a0d DB |
428 | return NULL; |
429 | ||
102eb975 GL |
430 | WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias)); |
431 | ||
8ae12a0d DB |
432 | proxy->chip_select = chip->chip_select; |
433 | proxy->max_speed_hz = chip->max_speed_hz; | |
980a01c9 | 434 | proxy->mode = chip->mode; |
8ae12a0d | 435 | proxy->irq = chip->irq; |
102eb975 | 436 | strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias)); |
8ae12a0d DB |
437 | proxy->dev.platform_data = (void *) chip->platform_data; |
438 | proxy->controller_data = chip->controller_data; | |
439 | proxy->controller_state = NULL; | |
8ae12a0d | 440 | |
dc87c98e | 441 | status = spi_add_device(proxy); |
8ae12a0d | 442 | if (status < 0) { |
dc87c98e GL |
443 | spi_dev_put(proxy); |
444 | return NULL; | |
8ae12a0d DB |
445 | } |
446 | ||
8ae12a0d DB |
447 | return proxy; |
448 | } | |
449 | EXPORT_SYMBOL_GPL(spi_new_device); | |
450 | ||
2b9603a0 FT |
451 | static void spi_match_master_to_boardinfo(struct spi_master *master, |
452 | struct spi_board_info *bi) | |
453 | { | |
454 | struct spi_device *dev; | |
455 | ||
456 | if (master->bus_num != bi->bus_num) | |
457 | return; | |
458 | ||
459 | dev = spi_new_device(master, bi); | |
460 | if (!dev) | |
461 | dev_err(master->dev.parent, "can't create new device for %s\n", | |
462 | bi->modalias); | |
463 | } | |
464 | ||
33e34dc6 DB |
465 | /** |
466 | * spi_register_board_info - register SPI devices for a given board | |
467 | * @info: array of chip descriptors | |
468 | * @n: how many descriptors are provided | |
469 | * Context: can sleep | |
470 | * | |
8ae12a0d DB |
471 | * Board-specific early init code calls this (probably during arch_initcall) |
472 | * with segments of the SPI device table. Any device nodes are created later, | |
473 | * after the relevant parent SPI controller (bus_num) is defined. We keep | |
474 | * this table of devices forever, so that reloading a controller driver will | |
475 | * not make Linux forget about these hard-wired devices. | |
476 | * | |
477 | * Other code can also call this, e.g. a particular add-on board might provide | |
478 | * SPI devices through its expansion connector, so code initializing that board | |
479 | * would naturally declare its SPI devices. | |
480 | * | |
481 | * The board info passed can safely be __initdata ... but be careful of | |
482 | * any embedded pointers (platform_data, etc), they're copied as-is. | |
483 | */ | |
484 | int __init | |
485 | spi_register_board_info(struct spi_board_info const *info, unsigned n) | |
486 | { | |
2b9603a0 FT |
487 | struct boardinfo *bi; |
488 | int i; | |
8ae12a0d | 489 | |
2b9603a0 | 490 | bi = kzalloc(n * sizeof(*bi), GFP_KERNEL); |
8ae12a0d DB |
491 | if (!bi) |
492 | return -ENOMEM; | |
8ae12a0d | 493 | |
2b9603a0 FT |
494 | for (i = 0; i < n; i++, bi++, info++) { |
495 | struct spi_master *master; | |
8ae12a0d | 496 | |
2b9603a0 FT |
497 | memcpy(&bi->board_info, info, sizeof(*info)); |
498 | mutex_lock(&board_lock); | |
499 | list_add_tail(&bi->list, &board_list); | |
500 | list_for_each_entry(master, &spi_master_list, list) | |
501 | spi_match_master_to_boardinfo(master, &bi->board_info); | |
502 | mutex_unlock(&board_lock); | |
8ae12a0d | 503 | } |
2b9603a0 FT |
504 | |
505 | return 0; | |
8ae12a0d DB |
506 | } |
507 | ||
508 | /*-------------------------------------------------------------------------*/ | |
509 | ||
49dce689 | 510 | static void spi_master_release(struct device *dev) |
8ae12a0d DB |
511 | { |
512 | struct spi_master *master; | |
513 | ||
49dce689 | 514 | master = container_of(dev, struct spi_master, dev); |
8ae12a0d DB |
515 | kfree(master); |
516 | } | |
517 | ||
518 | static struct class spi_master_class = { | |
519 | .name = "spi_master", | |
520 | .owner = THIS_MODULE, | |
49dce689 | 521 | .dev_release = spi_master_release, |
8ae12a0d DB |
522 | }; |
523 | ||
524 | ||
525 | /** | |
526 | * spi_alloc_master - allocate SPI master controller | |
527 | * @dev: the controller, possibly using the platform_bus | |
33e34dc6 | 528 | * @size: how much zeroed driver-private data to allocate; the pointer to this |
49dce689 | 529 | * memory is in the driver_data field of the returned device, |
0c868461 | 530 | * accessible with spi_master_get_devdata(). |
33e34dc6 | 531 | * Context: can sleep |
8ae12a0d DB |
532 | * |
533 | * This call is used only by SPI master controller drivers, which are the | |
534 | * only ones directly touching chip registers. It's how they allocate | |
ba1a0513 | 535 | * an spi_master structure, prior to calling spi_register_master(). |
8ae12a0d DB |
536 | * |
537 | * This must be called from context that can sleep. It returns the SPI | |
538 | * master structure on success, else NULL. | |
539 | * | |
540 | * The caller is responsible for assigning the bus number and initializing | |
ba1a0513 | 541 | * the master's methods before calling spi_register_master(); and (after errors |
0c868461 | 542 | * adding the device) calling spi_master_put() to prevent a memory leak. |
8ae12a0d | 543 | */ |
e9d5a461 | 544 | struct spi_master *spi_alloc_master(struct device *dev, unsigned size) |
8ae12a0d DB |
545 | { |
546 | struct spi_master *master; | |
547 | ||
0c868461 DB |
548 | if (!dev) |
549 | return NULL; | |
550 | ||
e94b1766 | 551 | master = kzalloc(size + sizeof *master, GFP_KERNEL); |
8ae12a0d DB |
552 | if (!master) |
553 | return NULL; | |
554 | ||
49dce689 TJ |
555 | device_initialize(&master->dev); |
556 | master->dev.class = &spi_master_class; | |
557 | master->dev.parent = get_device(dev); | |
0c868461 | 558 | spi_master_set_devdata(master, &master[1]); |
8ae12a0d DB |
559 | |
560 | return master; | |
561 | } | |
562 | EXPORT_SYMBOL_GPL(spi_alloc_master); | |
563 | ||
564 | /** | |
565 | * spi_register_master - register SPI master controller | |
566 | * @master: initialized master, originally from spi_alloc_master() | |
33e34dc6 | 567 | * Context: can sleep |
8ae12a0d DB |
568 | * |
569 | * SPI master controllers connect to their drivers using some non-SPI bus, | |
570 | * such as the platform bus. The final stage of probe() in that code | |
571 | * includes calling spi_register_master() to hook up to this SPI bus glue. | |
572 | * | |
573 | * SPI controllers use board specific (often SOC specific) bus numbers, | |
574 | * and board-specific addressing for SPI devices combines those numbers | |
575 | * with chip select numbers. Since SPI does not directly support dynamic | |
576 | * device identification, boards need configuration tables telling which | |
577 | * chip is at which address. | |
578 | * | |
579 | * This must be called from context that can sleep. It returns zero on | |
580 | * success, else a negative error code (dropping the master's refcount). | |
0c868461 DB |
581 | * After a successful return, the caller is responsible for calling |
582 | * spi_unregister_master(). | |
8ae12a0d | 583 | */ |
e9d5a461 | 584 | int spi_register_master(struct spi_master *master) |
8ae12a0d | 585 | { |
e44a45ae | 586 | static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1); |
49dce689 | 587 | struct device *dev = master->dev.parent; |
2b9603a0 | 588 | struct boardinfo *bi; |
8ae12a0d DB |
589 | int status = -ENODEV; |
590 | int dynamic = 0; | |
591 | ||
0c868461 DB |
592 | if (!dev) |
593 | return -ENODEV; | |
594 | ||
082c8cb4 DB |
595 | /* even if it's just one always-selected device, there must |
596 | * be at least one chipselect | |
597 | */ | |
598 | if (master->num_chipselect == 0) | |
599 | return -EINVAL; | |
600 | ||
8ae12a0d | 601 | /* convention: dynamically assigned bus IDs count down from the max */ |
a020ed75 | 602 | if (master->bus_num < 0) { |
082c8cb4 DB |
603 | /* FIXME switch to an IDR based scheme, something like |
604 | * I2C now uses, so we can't run out of "dynamic" IDs | |
605 | */ | |
8ae12a0d | 606 | master->bus_num = atomic_dec_return(&dyn_bus_id); |
b885244e | 607 | dynamic = 1; |
8ae12a0d DB |
608 | } |
609 | ||
cf32b71e ES |
610 | spin_lock_init(&master->bus_lock_spinlock); |
611 | mutex_init(&master->bus_lock_mutex); | |
612 | master->bus_lock_flag = 0; | |
613 | ||
8ae12a0d DB |
614 | /* register the device, then userspace will see it. |
615 | * registration fails if the bus ID is in use. | |
616 | */ | |
35f74fca | 617 | dev_set_name(&master->dev, "spi%u", master->bus_num); |
49dce689 | 618 | status = device_add(&master->dev); |
b885244e | 619 | if (status < 0) |
8ae12a0d | 620 | goto done; |
35f74fca | 621 | dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev), |
8ae12a0d DB |
622 | dynamic ? " (dynamic)" : ""); |
623 | ||
2b9603a0 FT |
624 | mutex_lock(&board_lock); |
625 | list_add_tail(&master->list, &spi_master_list); | |
626 | list_for_each_entry(bi, &board_list, list) | |
627 | spi_match_master_to_boardinfo(master, &bi->board_info); | |
628 | mutex_unlock(&board_lock); | |
629 | ||
8ae12a0d | 630 | status = 0; |
12b15e83 AG |
631 | |
632 | /* Register devices from the device tree */ | |
633 | of_register_spi_devices(master); | |
8ae12a0d DB |
634 | done: |
635 | return status; | |
636 | } | |
637 | EXPORT_SYMBOL_GPL(spi_register_master); | |
638 | ||
639 | ||
34860089 | 640 | static int __unregister(struct device *dev, void *null) |
8ae12a0d | 641 | { |
34860089 | 642 | spi_unregister_device(to_spi_device(dev)); |
8ae12a0d DB |
643 | return 0; |
644 | } | |
645 | ||
646 | /** | |
647 | * spi_unregister_master - unregister SPI master controller | |
648 | * @master: the master being unregistered | |
33e34dc6 | 649 | * Context: can sleep |
8ae12a0d DB |
650 | * |
651 | * This call is used only by SPI master controller drivers, which are the | |
652 | * only ones directly touching chip registers. | |
653 | * | |
654 | * This must be called from context that can sleep. | |
655 | */ | |
656 | void spi_unregister_master(struct spi_master *master) | |
657 | { | |
89fc9a1a JG |
658 | int dummy; |
659 | ||
2b9603a0 FT |
660 | mutex_lock(&board_lock); |
661 | list_del(&master->list); | |
662 | mutex_unlock(&board_lock); | |
663 | ||
97dbf37d | 664 | dummy = device_for_each_child(&master->dev, NULL, __unregister); |
49dce689 | 665 | device_unregister(&master->dev); |
8ae12a0d DB |
666 | } |
667 | EXPORT_SYMBOL_GPL(spi_unregister_master); | |
668 | ||
5ed2c832 DY |
669 | static int __spi_master_match(struct device *dev, void *data) |
670 | { | |
671 | struct spi_master *m; | |
672 | u16 *bus_num = data; | |
673 | ||
674 | m = container_of(dev, struct spi_master, dev); | |
675 | return m->bus_num == *bus_num; | |
676 | } | |
677 | ||
8ae12a0d DB |
678 | /** |
679 | * spi_busnum_to_master - look up master associated with bus_num | |
680 | * @bus_num: the master's bus number | |
33e34dc6 | 681 | * Context: can sleep |
8ae12a0d DB |
682 | * |
683 | * This call may be used with devices that are registered after | |
684 | * arch init time. It returns a refcounted pointer to the relevant | |
685 | * spi_master (which the caller must release), or NULL if there is | |
686 | * no such master registered. | |
687 | */ | |
688 | struct spi_master *spi_busnum_to_master(u16 bus_num) | |
689 | { | |
49dce689 | 690 | struct device *dev; |
1e9a51dc | 691 | struct spi_master *master = NULL; |
5ed2c832 | 692 | |
695794ae | 693 | dev = class_find_device(&spi_master_class, NULL, &bus_num, |
5ed2c832 DY |
694 | __spi_master_match); |
695 | if (dev) | |
696 | master = container_of(dev, struct spi_master, dev); | |
697 | /* reference got in class_find_device */ | |
1e9a51dc | 698 | return master; |
8ae12a0d DB |
699 | } |
700 | EXPORT_SYMBOL_GPL(spi_busnum_to_master); | |
701 | ||
702 | ||
703 | /*-------------------------------------------------------------------------*/ | |
704 | ||
7d077197 DB |
705 | /* Core methods for SPI master protocol drivers. Some of the |
706 | * other core methods are currently defined as inline functions. | |
707 | */ | |
708 | ||
709 | /** | |
710 | * spi_setup - setup SPI mode and clock rate | |
711 | * @spi: the device whose settings are being modified | |
712 | * Context: can sleep, and no requests are queued to the device | |
713 | * | |
714 | * SPI protocol drivers may need to update the transfer mode if the | |
715 | * device doesn't work with its default. They may likewise need | |
716 | * to update clock rates or word sizes from initial values. This function | |
717 | * changes those settings, and must be called from a context that can sleep. | |
718 | * Except for SPI_CS_HIGH, which takes effect immediately, the changes take | |
719 | * effect the next time the device is selected and data is transferred to | |
720 | * or from it. When this function returns, the spi device is deselected. | |
721 | * | |
722 | * Note that this call will fail if the protocol driver specifies an option | |
723 | * that the underlying controller or its driver does not support. For | |
724 | * example, not all hardware supports wire transfers using nine bit words, | |
725 | * LSB-first wire encoding, or active-high chipselects. | |
726 | */ | |
727 | int spi_setup(struct spi_device *spi) | |
728 | { | |
e7db06b5 | 729 | unsigned bad_bits; |
7d077197 DB |
730 | int status; |
731 | ||
e7db06b5 DB |
732 | /* help drivers fail *cleanly* when they need options |
733 | * that aren't supported with their current master | |
734 | */ | |
735 | bad_bits = spi->mode & ~spi->master->mode_bits; | |
736 | if (bad_bits) { | |
eb288a1f | 737 | dev_err(&spi->dev, "setup: unsupported mode bits %x\n", |
e7db06b5 DB |
738 | bad_bits); |
739 | return -EINVAL; | |
740 | } | |
741 | ||
7d077197 DB |
742 | if (!spi->bits_per_word) |
743 | spi->bits_per_word = 8; | |
744 | ||
745 | status = spi->master->setup(spi); | |
746 | ||
747 | dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s" | |
748 | "%u bits/w, %u Hz max --> %d\n", | |
749 | (int) (spi->mode & (SPI_CPOL | SPI_CPHA)), | |
750 | (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "", | |
751 | (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "", | |
752 | (spi->mode & SPI_3WIRE) ? "3wire, " : "", | |
753 | (spi->mode & SPI_LOOP) ? "loopback, " : "", | |
754 | spi->bits_per_word, spi->max_speed_hz, | |
755 | status); | |
756 | ||
757 | return status; | |
758 | } | |
759 | EXPORT_SYMBOL_GPL(spi_setup); | |
760 | ||
cf32b71e ES |
761 | static int __spi_async(struct spi_device *spi, struct spi_message *message) |
762 | { | |
763 | struct spi_master *master = spi->master; | |
764 | ||
765 | /* Half-duplex links include original MicroWire, and ones with | |
766 | * only one data pin like SPI_3WIRE (switches direction) or where | |
767 | * either MOSI or MISO is missing. They can also be caused by | |
768 | * software limitations. | |
769 | */ | |
770 | if ((master->flags & SPI_MASTER_HALF_DUPLEX) | |
771 | || (spi->mode & SPI_3WIRE)) { | |
772 | struct spi_transfer *xfer; | |
773 | unsigned flags = master->flags; | |
774 | ||
775 | list_for_each_entry(xfer, &message->transfers, transfer_list) { | |
776 | if (xfer->rx_buf && xfer->tx_buf) | |
777 | return -EINVAL; | |
778 | if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf) | |
779 | return -EINVAL; | |
780 | if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf) | |
781 | return -EINVAL; | |
782 | } | |
783 | } | |
784 | ||
785 | message->spi = spi; | |
786 | message->status = -EINPROGRESS; | |
787 | return master->transfer(spi, message); | |
788 | } | |
789 | ||
568d0697 DB |
790 | /** |
791 | * spi_async - asynchronous SPI transfer | |
792 | * @spi: device with which data will be exchanged | |
793 | * @message: describes the data transfers, including completion callback | |
794 | * Context: any (irqs may be blocked, etc) | |
795 | * | |
796 | * This call may be used in_irq and other contexts which can't sleep, | |
797 | * as well as from task contexts which can sleep. | |
798 | * | |
799 | * The completion callback is invoked in a context which can't sleep. | |
800 | * Before that invocation, the value of message->status is undefined. | |
801 | * When the callback is issued, message->status holds either zero (to | |
802 | * indicate complete success) or a negative error code. After that | |
803 | * callback returns, the driver which issued the transfer request may | |
804 | * deallocate the associated memory; it's no longer in use by any SPI | |
805 | * core or controller driver code. | |
806 | * | |
807 | * Note that although all messages to a spi_device are handled in | |
808 | * FIFO order, messages may go to different devices in other orders. | |
809 | * Some device might be higher priority, or have various "hard" access | |
810 | * time requirements, for example. | |
811 | * | |
812 | * On detection of any fault during the transfer, processing of | |
813 | * the entire message is aborted, and the device is deselected. | |
814 | * Until returning from the associated message completion callback, | |
815 | * no other spi_message queued to that device will be processed. | |
816 | * (This rule applies equally to all the synchronous transfer calls, | |
817 | * which are wrappers around this core asynchronous primitive.) | |
818 | */ | |
819 | int spi_async(struct spi_device *spi, struct spi_message *message) | |
820 | { | |
821 | struct spi_master *master = spi->master; | |
cf32b71e ES |
822 | int ret; |
823 | unsigned long flags; | |
568d0697 | 824 | |
cf32b71e | 825 | spin_lock_irqsave(&master->bus_lock_spinlock, flags); |
568d0697 | 826 | |
cf32b71e ES |
827 | if (master->bus_lock_flag) |
828 | ret = -EBUSY; | |
829 | else | |
830 | ret = __spi_async(spi, message); | |
568d0697 | 831 | |
cf32b71e ES |
832 | spin_unlock_irqrestore(&master->bus_lock_spinlock, flags); |
833 | ||
834 | return ret; | |
568d0697 DB |
835 | } |
836 | EXPORT_SYMBOL_GPL(spi_async); | |
837 | ||
cf32b71e ES |
838 | /** |
839 | * spi_async_locked - version of spi_async with exclusive bus usage | |
840 | * @spi: device with which data will be exchanged | |
841 | * @message: describes the data transfers, including completion callback | |
842 | * Context: any (irqs may be blocked, etc) | |
843 | * | |
844 | * This call may be used in_irq and other contexts which can't sleep, | |
845 | * as well as from task contexts which can sleep. | |
846 | * | |
847 | * The completion callback is invoked in a context which can't sleep. | |
848 | * Before that invocation, the value of message->status is undefined. | |
849 | * When the callback is issued, message->status holds either zero (to | |
850 | * indicate complete success) or a negative error code. After that | |
851 | * callback returns, the driver which issued the transfer request may | |
852 | * deallocate the associated memory; it's no longer in use by any SPI | |
853 | * core or controller driver code. | |
854 | * | |
855 | * Note that although all messages to a spi_device are handled in | |
856 | * FIFO order, messages may go to different devices in other orders. | |
857 | * Some device might be higher priority, or have various "hard" access | |
858 | * time requirements, for example. | |
859 | * | |
860 | * On detection of any fault during the transfer, processing of | |
861 | * the entire message is aborted, and the device is deselected. | |
862 | * Until returning from the associated message completion callback, | |
863 | * no other spi_message queued to that device will be processed. | |
864 | * (This rule applies equally to all the synchronous transfer calls, | |
865 | * which are wrappers around this core asynchronous primitive.) | |
866 | */ | |
867 | int spi_async_locked(struct spi_device *spi, struct spi_message *message) | |
868 | { | |
869 | struct spi_master *master = spi->master; | |
870 | int ret; | |
871 | unsigned long flags; | |
872 | ||
873 | spin_lock_irqsave(&master->bus_lock_spinlock, flags); | |
874 | ||
875 | ret = __spi_async(spi, message); | |
876 | ||
877 | spin_unlock_irqrestore(&master->bus_lock_spinlock, flags); | |
878 | ||
879 | return ret; | |
880 | ||
881 | } | |
882 | EXPORT_SYMBOL_GPL(spi_async_locked); | |
883 | ||
7d077197 DB |
884 | |
885 | /*-------------------------------------------------------------------------*/ | |
886 | ||
887 | /* Utility methods for SPI master protocol drivers, layered on | |
888 | * top of the core. Some other utility methods are defined as | |
889 | * inline functions. | |
890 | */ | |
891 | ||
5d870c8e AM |
892 | static void spi_complete(void *arg) |
893 | { | |
894 | complete(arg); | |
895 | } | |
896 | ||
cf32b71e ES |
897 | static int __spi_sync(struct spi_device *spi, struct spi_message *message, |
898 | int bus_locked) | |
899 | { | |
900 | DECLARE_COMPLETION_ONSTACK(done); | |
901 | int status; | |
902 | struct spi_master *master = spi->master; | |
903 | ||
904 | message->complete = spi_complete; | |
905 | message->context = &done; | |
906 | ||
907 | if (!bus_locked) | |
908 | mutex_lock(&master->bus_lock_mutex); | |
909 | ||
910 | status = spi_async_locked(spi, message); | |
911 | ||
912 | if (!bus_locked) | |
913 | mutex_unlock(&master->bus_lock_mutex); | |
914 | ||
915 | if (status == 0) { | |
916 | wait_for_completion(&done); | |
917 | status = message->status; | |
918 | } | |
919 | message->context = NULL; | |
920 | return status; | |
921 | } | |
922 | ||
8ae12a0d DB |
923 | /** |
924 | * spi_sync - blocking/synchronous SPI data transfers | |
925 | * @spi: device with which data will be exchanged | |
926 | * @message: describes the data transfers | |
33e34dc6 | 927 | * Context: can sleep |
8ae12a0d DB |
928 | * |
929 | * This call may only be used from a context that may sleep. The sleep | |
930 | * is non-interruptible, and has no timeout. Low-overhead controller | |
931 | * drivers may DMA directly into and out of the message buffers. | |
932 | * | |
933 | * Note that the SPI device's chip select is active during the message, | |
934 | * and then is normally disabled between messages. Drivers for some | |
935 | * frequently-used devices may want to minimize costs of selecting a chip, | |
936 | * by leaving it selected in anticipation that the next message will go | |
937 | * to the same chip. (That may increase power usage.) | |
938 | * | |
0c868461 DB |
939 | * Also, the caller is guaranteeing that the memory associated with the |
940 | * message will not be freed before this call returns. | |
941 | * | |
9b938b74 | 942 | * It returns zero on success, else a negative error code. |
8ae12a0d DB |
943 | */ |
944 | int spi_sync(struct spi_device *spi, struct spi_message *message) | |
945 | { | |
cf32b71e | 946 | return __spi_sync(spi, message, 0); |
8ae12a0d DB |
947 | } |
948 | EXPORT_SYMBOL_GPL(spi_sync); | |
949 | ||
cf32b71e ES |
950 | /** |
951 | * spi_sync_locked - version of spi_sync with exclusive bus usage | |
952 | * @spi: device with which data will be exchanged | |
953 | * @message: describes the data transfers | |
954 | * Context: can sleep | |
955 | * | |
956 | * This call may only be used from a context that may sleep. The sleep | |
957 | * is non-interruptible, and has no timeout. Low-overhead controller | |
958 | * drivers may DMA directly into and out of the message buffers. | |
959 | * | |
960 | * This call should be used by drivers that require exclusive access to the | |
25985edc | 961 | * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must |
cf32b71e ES |
962 | * be released by a spi_bus_unlock call when the exclusive access is over. |
963 | * | |
964 | * It returns zero on success, else a negative error code. | |
965 | */ | |
966 | int spi_sync_locked(struct spi_device *spi, struct spi_message *message) | |
967 | { | |
968 | return __spi_sync(spi, message, 1); | |
969 | } | |
970 | EXPORT_SYMBOL_GPL(spi_sync_locked); | |
971 | ||
972 | /** | |
973 | * spi_bus_lock - obtain a lock for exclusive SPI bus usage | |
974 | * @master: SPI bus master that should be locked for exclusive bus access | |
975 | * Context: can sleep | |
976 | * | |
977 | * This call may only be used from a context that may sleep. The sleep | |
978 | * is non-interruptible, and has no timeout. | |
979 | * | |
980 | * This call should be used by drivers that require exclusive access to the | |
981 | * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the | |
982 | * exclusive access is over. Data transfer must be done by spi_sync_locked | |
983 | * and spi_async_locked calls when the SPI bus lock is held. | |
984 | * | |
985 | * It returns zero on success, else a negative error code. | |
986 | */ | |
987 | int spi_bus_lock(struct spi_master *master) | |
988 | { | |
989 | unsigned long flags; | |
990 | ||
991 | mutex_lock(&master->bus_lock_mutex); | |
992 | ||
993 | spin_lock_irqsave(&master->bus_lock_spinlock, flags); | |
994 | master->bus_lock_flag = 1; | |
995 | spin_unlock_irqrestore(&master->bus_lock_spinlock, flags); | |
996 | ||
997 | /* mutex remains locked until spi_bus_unlock is called */ | |
998 | ||
999 | return 0; | |
1000 | } | |
1001 | EXPORT_SYMBOL_GPL(spi_bus_lock); | |
1002 | ||
1003 | /** | |
1004 | * spi_bus_unlock - release the lock for exclusive SPI bus usage | |
1005 | * @master: SPI bus master that was locked for exclusive bus access | |
1006 | * Context: can sleep | |
1007 | * | |
1008 | * This call may only be used from a context that may sleep. The sleep | |
1009 | * is non-interruptible, and has no timeout. | |
1010 | * | |
1011 | * This call releases an SPI bus lock previously obtained by an spi_bus_lock | |
1012 | * call. | |
1013 | * | |
1014 | * It returns zero on success, else a negative error code. | |
1015 | */ | |
1016 | int spi_bus_unlock(struct spi_master *master) | |
1017 | { | |
1018 | master->bus_lock_flag = 0; | |
1019 | ||
1020 | mutex_unlock(&master->bus_lock_mutex); | |
1021 | ||
1022 | return 0; | |
1023 | } | |
1024 | EXPORT_SYMBOL_GPL(spi_bus_unlock); | |
1025 | ||
a9948b61 DB |
1026 | /* portable code must never pass more than 32 bytes */ |
1027 | #define SPI_BUFSIZ max(32,SMP_CACHE_BYTES) | |
8ae12a0d DB |
1028 | |
1029 | static u8 *buf; | |
1030 | ||
1031 | /** | |
1032 | * spi_write_then_read - SPI synchronous write followed by read | |
1033 | * @spi: device with which data will be exchanged | |
1034 | * @txbuf: data to be written (need not be dma-safe) | |
1035 | * @n_tx: size of txbuf, in bytes | |
27570497 JP |
1036 | * @rxbuf: buffer into which data will be read (need not be dma-safe) |
1037 | * @n_rx: size of rxbuf, in bytes | |
33e34dc6 | 1038 | * Context: can sleep |
8ae12a0d DB |
1039 | * |
1040 | * This performs a half duplex MicroWire style transaction with the | |
1041 | * device, sending txbuf and then reading rxbuf. The return value | |
1042 | * is zero for success, else a negative errno status code. | |
b885244e | 1043 | * This call may only be used from a context that may sleep. |
8ae12a0d | 1044 | * |
0c868461 | 1045 | * Parameters to this routine are always copied using a small buffer; |
33e34dc6 DB |
1046 | * portable code should never use this for more than 32 bytes. |
1047 | * Performance-sensitive or bulk transfer code should instead use | |
0c868461 | 1048 | * spi_{async,sync}() calls with dma-safe buffers. |
8ae12a0d DB |
1049 | */ |
1050 | int spi_write_then_read(struct spi_device *spi, | |
0c4a1590 MB |
1051 | const void *txbuf, unsigned n_tx, |
1052 | void *rxbuf, unsigned n_rx) | |
8ae12a0d | 1053 | { |
068f4070 | 1054 | static DEFINE_MUTEX(lock); |
8ae12a0d DB |
1055 | |
1056 | int status; | |
1057 | struct spi_message message; | |
bdff549e | 1058 | struct spi_transfer x[2]; |
8ae12a0d DB |
1059 | u8 *local_buf; |
1060 | ||
1061 | /* Use preallocated DMA-safe buffer. We can't avoid copying here, | |
1062 | * (as a pure convenience thing), but we can keep heap costs | |
1063 | * out of the hot path ... | |
1064 | */ | |
1065 | if ((n_tx + n_rx) > SPI_BUFSIZ) | |
1066 | return -EINVAL; | |
1067 | ||
8275c642 | 1068 | spi_message_init(&message); |
bdff549e DB |
1069 | memset(x, 0, sizeof x); |
1070 | if (n_tx) { | |
1071 | x[0].len = n_tx; | |
1072 | spi_message_add_tail(&x[0], &message); | |
1073 | } | |
1074 | if (n_rx) { | |
1075 | x[1].len = n_rx; | |
1076 | spi_message_add_tail(&x[1], &message); | |
1077 | } | |
8275c642 | 1078 | |
8ae12a0d | 1079 | /* ... unless someone else is using the pre-allocated buffer */ |
068f4070 | 1080 | if (!mutex_trylock(&lock)) { |
8ae12a0d DB |
1081 | local_buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL); |
1082 | if (!local_buf) | |
1083 | return -ENOMEM; | |
1084 | } else | |
1085 | local_buf = buf; | |
1086 | ||
8ae12a0d | 1087 | memcpy(local_buf, txbuf, n_tx); |
bdff549e DB |
1088 | x[0].tx_buf = local_buf; |
1089 | x[1].rx_buf = local_buf + n_tx; | |
8ae12a0d DB |
1090 | |
1091 | /* do the i/o */ | |
8ae12a0d | 1092 | status = spi_sync(spi, &message); |
9b938b74 | 1093 | if (status == 0) |
bdff549e | 1094 | memcpy(rxbuf, x[1].rx_buf, n_rx); |
8ae12a0d | 1095 | |
bdff549e | 1096 | if (x[0].tx_buf == buf) |
068f4070 | 1097 | mutex_unlock(&lock); |
8ae12a0d DB |
1098 | else |
1099 | kfree(local_buf); | |
1100 | ||
1101 | return status; | |
1102 | } | |
1103 | EXPORT_SYMBOL_GPL(spi_write_then_read); | |
1104 | ||
1105 | /*-------------------------------------------------------------------------*/ | |
1106 | ||
1107 | static int __init spi_init(void) | |
1108 | { | |
b885244e DB |
1109 | int status; |
1110 | ||
e94b1766 | 1111 | buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL); |
b885244e DB |
1112 | if (!buf) { |
1113 | status = -ENOMEM; | |
1114 | goto err0; | |
1115 | } | |
1116 | ||
1117 | status = bus_register(&spi_bus_type); | |
1118 | if (status < 0) | |
1119 | goto err1; | |
8ae12a0d | 1120 | |
b885244e DB |
1121 | status = class_register(&spi_master_class); |
1122 | if (status < 0) | |
1123 | goto err2; | |
8ae12a0d | 1124 | return 0; |
b885244e DB |
1125 | |
1126 | err2: | |
1127 | bus_unregister(&spi_bus_type); | |
1128 | err1: | |
1129 | kfree(buf); | |
1130 | buf = NULL; | |
1131 | err0: | |
1132 | return status; | |
8ae12a0d | 1133 | } |
b885244e | 1134 | |
8ae12a0d DB |
1135 | /* board_info is normally registered in arch_initcall(), |
1136 | * but even essential drivers wait till later | |
b885244e DB |
1137 | * |
1138 | * REVISIT only boardinfo really needs static linking. the rest (device and | |
1139 | * driver registration) _could_ be dynamically linked (modular) ... costs | |
1140 | * include needing to have boardinfo data structures be much more public. | |
8ae12a0d | 1141 | */ |
673c0c00 | 1142 | postcore_initcall(spi_init); |
8ae12a0d | 1143 |