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