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 DB |
60 | } |
61 | ||
62 | static struct device_attribute spi_dev_attrs[] = { | |
63 | __ATTR_RO(modalias), | |
64 | __ATTR_NULL, | |
65 | }; | |
66 | ||
67 | /* modalias support makes "modprobe $MODALIAS" new-style hotplug work, | |
68 | * and the sysfs version makes coldplug work too. | |
69 | */ | |
70 | ||
75368bf6 AV |
71 | static const struct spi_device_id *spi_match_id(const struct spi_device_id *id, |
72 | const struct spi_device *sdev) | |
73 | { | |
74 | while (id->name[0]) { | |
75 | if (!strcmp(sdev->modalias, id->name)) | |
76 | return id; | |
77 | id++; | |
78 | } | |
79 | return NULL; | |
80 | } | |
81 | ||
82 | const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev) | |
83 | { | |
84 | const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver); | |
85 | ||
86 | return spi_match_id(sdrv->id_table, sdev); | |
87 | } | |
88 | EXPORT_SYMBOL_GPL(spi_get_device_id); | |
89 | ||
8ae12a0d DB |
90 | static int spi_match_device(struct device *dev, struct device_driver *drv) |
91 | { | |
92 | const struct spi_device *spi = to_spi_device(dev); | |
75368bf6 AV |
93 | const struct spi_driver *sdrv = to_spi_driver(drv); |
94 | ||
2b7a32f7 SA |
95 | /* Attempt an OF style match */ |
96 | if (of_driver_match_device(dev, drv)) | |
97 | return 1; | |
98 | ||
64bee4d2 MW |
99 | /* Then try ACPI */ |
100 | if (acpi_driver_match_device(dev, drv)) | |
101 | return 1; | |
102 | ||
75368bf6 AV |
103 | if (sdrv->id_table) |
104 | return !!spi_match_id(sdrv->id_table, spi); | |
8ae12a0d | 105 | |
35f74fca | 106 | return strcmp(spi->modalias, drv->name) == 0; |
8ae12a0d DB |
107 | } |
108 | ||
7eff2e7a | 109 | static int spi_uevent(struct device *dev, struct kobj_uevent_env *env) |
8ae12a0d DB |
110 | { |
111 | const struct spi_device *spi = to_spi_device(dev); | |
112 | ||
e0626e38 | 113 | add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias); |
8ae12a0d DB |
114 | return 0; |
115 | } | |
116 | ||
3ae22e8c MB |
117 | #ifdef CONFIG_PM_SLEEP |
118 | static int spi_legacy_suspend(struct device *dev, pm_message_t message) | |
8ae12a0d | 119 | { |
3c72426f | 120 | int value = 0; |
b885244e | 121 | struct spi_driver *drv = to_spi_driver(dev->driver); |
8ae12a0d | 122 | |
8ae12a0d | 123 | /* suspend will stop irqs and dma; no more i/o */ |
3c72426f DB |
124 | if (drv) { |
125 | if (drv->suspend) | |
126 | value = drv->suspend(to_spi_device(dev), message); | |
127 | else | |
128 | dev_dbg(dev, "... can't suspend\n"); | |
129 | } | |
8ae12a0d DB |
130 | return value; |
131 | } | |
132 | ||
3ae22e8c | 133 | static int spi_legacy_resume(struct device *dev) |
8ae12a0d | 134 | { |
3c72426f | 135 | int value = 0; |
b885244e | 136 | struct spi_driver *drv = to_spi_driver(dev->driver); |
8ae12a0d | 137 | |
8ae12a0d | 138 | /* resume may restart the i/o queue */ |
3c72426f DB |
139 | if (drv) { |
140 | if (drv->resume) | |
141 | value = drv->resume(to_spi_device(dev)); | |
142 | else | |
143 | dev_dbg(dev, "... can't resume\n"); | |
144 | } | |
8ae12a0d DB |
145 | return value; |
146 | } | |
147 | ||
3ae22e8c MB |
148 | static int spi_pm_suspend(struct device *dev) |
149 | { | |
150 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
151 | ||
152 | if (pm) | |
153 | return pm_generic_suspend(dev); | |
154 | else | |
155 | return spi_legacy_suspend(dev, PMSG_SUSPEND); | |
156 | } | |
157 | ||
158 | static int spi_pm_resume(struct device *dev) | |
159 | { | |
160 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
161 | ||
162 | if (pm) | |
163 | return pm_generic_resume(dev); | |
164 | else | |
165 | return spi_legacy_resume(dev); | |
166 | } | |
167 | ||
168 | static int spi_pm_freeze(struct device *dev) | |
169 | { | |
170 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
171 | ||
172 | if (pm) | |
173 | return pm_generic_freeze(dev); | |
174 | else | |
175 | return spi_legacy_suspend(dev, PMSG_FREEZE); | |
176 | } | |
177 | ||
178 | static int spi_pm_thaw(struct device *dev) | |
179 | { | |
180 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
181 | ||
182 | if (pm) | |
183 | return pm_generic_thaw(dev); | |
184 | else | |
185 | return spi_legacy_resume(dev); | |
186 | } | |
187 | ||
188 | static int spi_pm_poweroff(struct device *dev) | |
189 | { | |
190 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
191 | ||
192 | if (pm) | |
193 | return pm_generic_poweroff(dev); | |
194 | else | |
195 | return spi_legacy_suspend(dev, PMSG_HIBERNATE); | |
196 | } | |
197 | ||
198 | static int spi_pm_restore(struct device *dev) | |
199 | { | |
200 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
201 | ||
202 | if (pm) | |
203 | return pm_generic_restore(dev); | |
204 | else | |
205 | return spi_legacy_resume(dev); | |
206 | } | |
8ae12a0d | 207 | #else |
3ae22e8c MB |
208 | #define spi_pm_suspend NULL |
209 | #define spi_pm_resume NULL | |
210 | #define spi_pm_freeze NULL | |
211 | #define spi_pm_thaw NULL | |
212 | #define spi_pm_poweroff NULL | |
213 | #define spi_pm_restore NULL | |
8ae12a0d DB |
214 | #endif |
215 | ||
3ae22e8c MB |
216 | static const struct dev_pm_ops spi_pm = { |
217 | .suspend = spi_pm_suspend, | |
218 | .resume = spi_pm_resume, | |
219 | .freeze = spi_pm_freeze, | |
220 | .thaw = spi_pm_thaw, | |
221 | .poweroff = spi_pm_poweroff, | |
222 | .restore = spi_pm_restore, | |
223 | SET_RUNTIME_PM_OPS( | |
224 | pm_generic_runtime_suspend, | |
225 | pm_generic_runtime_resume, | |
226 | pm_generic_runtime_idle | |
227 | ) | |
228 | }; | |
229 | ||
8ae12a0d DB |
230 | struct bus_type spi_bus_type = { |
231 | .name = "spi", | |
232 | .dev_attrs = spi_dev_attrs, | |
233 | .match = spi_match_device, | |
234 | .uevent = spi_uevent, | |
3ae22e8c | 235 | .pm = &spi_pm, |
8ae12a0d DB |
236 | }; |
237 | EXPORT_SYMBOL_GPL(spi_bus_type); | |
238 | ||
b885244e DB |
239 | |
240 | static int spi_drv_probe(struct device *dev) | |
241 | { | |
242 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); | |
243 | ||
244 | return sdrv->probe(to_spi_device(dev)); | |
245 | } | |
246 | ||
247 | static int spi_drv_remove(struct device *dev) | |
248 | { | |
249 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); | |
250 | ||
251 | return sdrv->remove(to_spi_device(dev)); | |
252 | } | |
253 | ||
254 | static void spi_drv_shutdown(struct device *dev) | |
255 | { | |
256 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); | |
257 | ||
258 | sdrv->shutdown(to_spi_device(dev)); | |
259 | } | |
260 | ||
33e34dc6 DB |
261 | /** |
262 | * spi_register_driver - register a SPI driver | |
263 | * @sdrv: the driver to register | |
264 | * Context: can sleep | |
265 | */ | |
b885244e DB |
266 | int spi_register_driver(struct spi_driver *sdrv) |
267 | { | |
268 | sdrv->driver.bus = &spi_bus_type; | |
269 | if (sdrv->probe) | |
270 | sdrv->driver.probe = spi_drv_probe; | |
271 | if (sdrv->remove) | |
272 | sdrv->driver.remove = spi_drv_remove; | |
273 | if (sdrv->shutdown) | |
274 | sdrv->driver.shutdown = spi_drv_shutdown; | |
275 | return driver_register(&sdrv->driver); | |
276 | } | |
277 | EXPORT_SYMBOL_GPL(spi_register_driver); | |
278 | ||
8ae12a0d DB |
279 | /*-------------------------------------------------------------------------*/ |
280 | ||
281 | /* SPI devices should normally not be created by SPI device drivers; that | |
282 | * would make them board-specific. Similarly with SPI master drivers. | |
283 | * Device registration normally goes into like arch/.../mach.../board-YYY.c | |
284 | * with other readonly (flashable) information about mainboard devices. | |
285 | */ | |
286 | ||
287 | struct boardinfo { | |
288 | struct list_head list; | |
2b9603a0 | 289 | struct spi_board_info board_info; |
8ae12a0d DB |
290 | }; |
291 | ||
292 | static LIST_HEAD(board_list); | |
2b9603a0 FT |
293 | static LIST_HEAD(spi_master_list); |
294 | ||
295 | /* | |
296 | * Used to protect add/del opertion for board_info list and | |
297 | * spi_master list, and their matching process | |
298 | */ | |
94040828 | 299 | static DEFINE_MUTEX(board_lock); |
8ae12a0d | 300 | |
dc87c98e GL |
301 | /** |
302 | * spi_alloc_device - Allocate a new SPI device | |
303 | * @master: Controller to which device is connected | |
304 | * Context: can sleep | |
305 | * | |
306 | * Allows a driver to allocate and initialize a spi_device without | |
307 | * registering it immediately. This allows a driver to directly | |
308 | * fill the spi_device with device parameters before calling | |
309 | * spi_add_device() on it. | |
310 | * | |
311 | * Caller is responsible to call spi_add_device() on the returned | |
312 | * spi_device structure to add it to the SPI master. If the caller | |
313 | * needs to discard the spi_device without adding it, then it should | |
314 | * call spi_dev_put() on it. | |
315 | * | |
316 | * Returns a pointer to the new device, or NULL. | |
317 | */ | |
318 | struct spi_device *spi_alloc_device(struct spi_master *master) | |
319 | { | |
320 | struct spi_device *spi; | |
321 | struct device *dev = master->dev.parent; | |
322 | ||
323 | if (!spi_master_get(master)) | |
324 | return NULL; | |
325 | ||
326 | spi = kzalloc(sizeof *spi, GFP_KERNEL); | |
327 | if (!spi) { | |
328 | dev_err(dev, "cannot alloc spi_device\n"); | |
329 | spi_master_put(master); | |
330 | return NULL; | |
331 | } | |
332 | ||
333 | spi->master = master; | |
178db7d3 | 334 | spi->dev.parent = &master->dev; |
dc87c98e GL |
335 | spi->dev.bus = &spi_bus_type; |
336 | spi->dev.release = spidev_release; | |
74317984 | 337 | spi->cs_gpio = -EINVAL; |
dc87c98e GL |
338 | device_initialize(&spi->dev); |
339 | return spi; | |
340 | } | |
341 | EXPORT_SYMBOL_GPL(spi_alloc_device); | |
342 | ||
343 | /** | |
344 | * spi_add_device - Add spi_device allocated with spi_alloc_device | |
345 | * @spi: spi_device to register | |
346 | * | |
347 | * Companion function to spi_alloc_device. Devices allocated with | |
348 | * spi_alloc_device can be added onto the spi bus with this function. | |
349 | * | |
e48880e0 | 350 | * Returns 0 on success; negative errno on failure |
dc87c98e GL |
351 | */ |
352 | int spi_add_device(struct spi_device *spi) | |
353 | { | |
e48880e0 | 354 | static DEFINE_MUTEX(spi_add_lock); |
74317984 JCPV |
355 | struct spi_master *master = spi->master; |
356 | struct device *dev = master->dev.parent; | |
8ec130a0 | 357 | struct device *d; |
dc87c98e GL |
358 | int status; |
359 | ||
360 | /* Chipselects are numbered 0..max; validate. */ | |
74317984 | 361 | if (spi->chip_select >= master->num_chipselect) { |
dc87c98e GL |
362 | dev_err(dev, "cs%d >= max %d\n", |
363 | spi->chip_select, | |
74317984 | 364 | master->num_chipselect); |
dc87c98e GL |
365 | return -EINVAL; |
366 | } | |
367 | ||
368 | /* Set the bus ID string */ | |
35f74fca | 369 | dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev), |
dc87c98e GL |
370 | spi->chip_select); |
371 | ||
e48880e0 DB |
372 | |
373 | /* We need to make sure there's no other device with this | |
374 | * chipselect **BEFORE** we call setup(), else we'll trash | |
375 | * its configuration. Lock against concurrent add() calls. | |
376 | */ | |
377 | mutex_lock(&spi_add_lock); | |
378 | ||
8ec130a0 RT |
379 | d = bus_find_device_by_name(&spi_bus_type, NULL, dev_name(&spi->dev)); |
380 | if (d != NULL) { | |
e48880e0 DB |
381 | dev_err(dev, "chipselect %d already in use\n", |
382 | spi->chip_select); | |
8ec130a0 | 383 | put_device(d); |
e48880e0 DB |
384 | status = -EBUSY; |
385 | goto done; | |
386 | } | |
387 | ||
74317984 JCPV |
388 | if (master->cs_gpios) |
389 | spi->cs_gpio = master->cs_gpios[spi->chip_select]; | |
390 | ||
e48880e0 DB |
391 | /* Drivers may modify this initial i/o setup, but will |
392 | * normally rely on the device being setup. Devices | |
393 | * using SPI_CS_HIGH can't coexist well otherwise... | |
394 | */ | |
7d077197 | 395 | status = spi_setup(spi); |
dc87c98e | 396 | if (status < 0) { |
eb288a1f LW |
397 | dev_err(dev, "can't setup %s, status %d\n", |
398 | dev_name(&spi->dev), status); | |
e48880e0 | 399 | goto done; |
dc87c98e GL |
400 | } |
401 | ||
e48880e0 | 402 | /* Device may be bound to an active driver when this returns */ |
dc87c98e | 403 | status = device_add(&spi->dev); |
e48880e0 | 404 | if (status < 0) |
eb288a1f LW |
405 | dev_err(dev, "can't add %s, status %d\n", |
406 | dev_name(&spi->dev), status); | |
e48880e0 | 407 | else |
35f74fca | 408 | dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev)); |
dc87c98e | 409 | |
e48880e0 DB |
410 | done: |
411 | mutex_unlock(&spi_add_lock); | |
412 | return status; | |
dc87c98e GL |
413 | } |
414 | EXPORT_SYMBOL_GPL(spi_add_device); | |
8ae12a0d | 415 | |
33e34dc6 DB |
416 | /** |
417 | * spi_new_device - instantiate one new SPI device | |
418 | * @master: Controller to which device is connected | |
419 | * @chip: Describes the SPI device | |
420 | * Context: can sleep | |
421 | * | |
422 | * On typical mainboards, this is purely internal; and it's not needed | |
8ae12a0d DB |
423 | * after board init creates the hard-wired devices. Some development |
424 | * platforms may not be able to use spi_register_board_info though, and | |
425 | * this is exported so that for example a USB or parport based adapter | |
426 | * driver could add devices (which it would learn about out-of-band). | |
082c8cb4 DB |
427 | * |
428 | * Returns the new device, or NULL. | |
8ae12a0d | 429 | */ |
e9d5a461 AB |
430 | struct spi_device *spi_new_device(struct spi_master *master, |
431 | struct spi_board_info *chip) | |
8ae12a0d DB |
432 | { |
433 | struct spi_device *proxy; | |
8ae12a0d DB |
434 | int status; |
435 | ||
082c8cb4 DB |
436 | /* NOTE: caller did any chip->bus_num checks necessary. |
437 | * | |
438 | * Also, unless we change the return value convention to use | |
439 | * error-or-pointer (not NULL-or-pointer), troubleshootability | |
440 | * suggests syslogged diagnostics are best here (ugh). | |
441 | */ | |
442 | ||
dc87c98e GL |
443 | proxy = spi_alloc_device(master); |
444 | if (!proxy) | |
8ae12a0d DB |
445 | return NULL; |
446 | ||
102eb975 GL |
447 | WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias)); |
448 | ||
8ae12a0d DB |
449 | proxy->chip_select = chip->chip_select; |
450 | proxy->max_speed_hz = chip->max_speed_hz; | |
980a01c9 | 451 | proxy->mode = chip->mode; |
8ae12a0d | 452 | proxy->irq = chip->irq; |
102eb975 | 453 | strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias)); |
8ae12a0d DB |
454 | proxy->dev.platform_data = (void *) chip->platform_data; |
455 | proxy->controller_data = chip->controller_data; | |
456 | proxy->controller_state = NULL; | |
8ae12a0d | 457 | |
dc87c98e | 458 | status = spi_add_device(proxy); |
8ae12a0d | 459 | if (status < 0) { |
dc87c98e GL |
460 | spi_dev_put(proxy); |
461 | return NULL; | |
8ae12a0d DB |
462 | } |
463 | ||
8ae12a0d DB |
464 | return proxy; |
465 | } | |
466 | EXPORT_SYMBOL_GPL(spi_new_device); | |
467 | ||
2b9603a0 FT |
468 | static void spi_match_master_to_boardinfo(struct spi_master *master, |
469 | struct spi_board_info *bi) | |
470 | { | |
471 | struct spi_device *dev; | |
472 | ||
473 | if (master->bus_num != bi->bus_num) | |
474 | return; | |
475 | ||
476 | dev = spi_new_device(master, bi); | |
477 | if (!dev) | |
478 | dev_err(master->dev.parent, "can't create new device for %s\n", | |
479 | bi->modalias); | |
480 | } | |
481 | ||
33e34dc6 DB |
482 | /** |
483 | * spi_register_board_info - register SPI devices for a given board | |
484 | * @info: array of chip descriptors | |
485 | * @n: how many descriptors are provided | |
486 | * Context: can sleep | |
487 | * | |
8ae12a0d DB |
488 | * Board-specific early init code calls this (probably during arch_initcall) |
489 | * with segments of the SPI device table. Any device nodes are created later, | |
490 | * after the relevant parent SPI controller (bus_num) is defined. We keep | |
491 | * this table of devices forever, so that reloading a controller driver will | |
492 | * not make Linux forget about these hard-wired devices. | |
493 | * | |
494 | * Other code can also call this, e.g. a particular add-on board might provide | |
495 | * SPI devices through its expansion connector, so code initializing that board | |
496 | * would naturally declare its SPI devices. | |
497 | * | |
498 | * The board info passed can safely be __initdata ... but be careful of | |
499 | * any embedded pointers (platform_data, etc), they're copied as-is. | |
500 | */ | |
fd4a319b | 501 | int spi_register_board_info(struct spi_board_info const *info, unsigned n) |
8ae12a0d | 502 | { |
2b9603a0 FT |
503 | struct boardinfo *bi; |
504 | int i; | |
8ae12a0d | 505 | |
2b9603a0 | 506 | bi = kzalloc(n * sizeof(*bi), GFP_KERNEL); |
8ae12a0d DB |
507 | if (!bi) |
508 | return -ENOMEM; | |
8ae12a0d | 509 | |
2b9603a0 FT |
510 | for (i = 0; i < n; i++, bi++, info++) { |
511 | struct spi_master *master; | |
8ae12a0d | 512 | |
2b9603a0 FT |
513 | memcpy(&bi->board_info, info, sizeof(*info)); |
514 | mutex_lock(&board_lock); | |
515 | list_add_tail(&bi->list, &board_list); | |
516 | list_for_each_entry(master, &spi_master_list, list) | |
517 | spi_match_master_to_boardinfo(master, &bi->board_info); | |
518 | mutex_unlock(&board_lock); | |
8ae12a0d | 519 | } |
2b9603a0 FT |
520 | |
521 | return 0; | |
8ae12a0d DB |
522 | } |
523 | ||
524 | /*-------------------------------------------------------------------------*/ | |
525 | ||
ffbbdd21 LW |
526 | /** |
527 | * spi_pump_messages - kthread work function which processes spi message queue | |
528 | * @work: pointer to kthread work struct contained in the master struct | |
529 | * | |
530 | * This function checks if there is any spi message in the queue that | |
531 | * needs processing and if so call out to the driver to initialize hardware | |
532 | * and transfer each message. | |
533 | * | |
534 | */ | |
535 | static void spi_pump_messages(struct kthread_work *work) | |
536 | { | |
537 | struct spi_master *master = | |
538 | container_of(work, struct spi_master, pump_messages); | |
539 | unsigned long flags; | |
540 | bool was_busy = false; | |
541 | int ret; | |
542 | ||
543 | /* Lock queue and check for queue work */ | |
544 | spin_lock_irqsave(&master->queue_lock, flags); | |
545 | if (list_empty(&master->queue) || !master->running) { | |
7dfd2bd7 | 546 | if (master->busy && master->unprepare_transfer_hardware) { |
ffbbdd21 LW |
547 | ret = master->unprepare_transfer_hardware(master); |
548 | if (ret) { | |
9af4acc0 | 549 | spin_unlock_irqrestore(&master->queue_lock, flags); |
ffbbdd21 LW |
550 | dev_err(&master->dev, |
551 | "failed to unprepare transfer hardware\n"); | |
552 | return; | |
553 | } | |
554 | } | |
555 | master->busy = false; | |
556 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
557 | return; | |
558 | } | |
559 | ||
560 | /* Make sure we are not already running a message */ | |
561 | if (master->cur_msg) { | |
562 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
563 | return; | |
564 | } | |
565 | /* Extract head of queue */ | |
566 | master->cur_msg = | |
567 | list_entry(master->queue.next, struct spi_message, queue); | |
568 | ||
569 | list_del_init(&master->cur_msg->queue); | |
570 | if (master->busy) | |
571 | was_busy = true; | |
572 | else | |
573 | master->busy = true; | |
574 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
575 | ||
7dfd2bd7 | 576 | if (!was_busy && master->prepare_transfer_hardware) { |
ffbbdd21 LW |
577 | ret = master->prepare_transfer_hardware(master); |
578 | if (ret) { | |
579 | dev_err(&master->dev, | |
580 | "failed to prepare transfer hardware\n"); | |
581 | return; | |
582 | } | |
583 | } | |
584 | ||
585 | ret = master->transfer_one_message(master, master->cur_msg); | |
586 | if (ret) { | |
587 | dev_err(&master->dev, | |
588 | "failed to transfer one message from queue\n"); | |
589 | return; | |
590 | } | |
591 | } | |
592 | ||
593 | static int spi_init_queue(struct spi_master *master) | |
594 | { | |
595 | struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 }; | |
596 | ||
597 | INIT_LIST_HEAD(&master->queue); | |
598 | spin_lock_init(&master->queue_lock); | |
599 | ||
600 | master->running = false; | |
601 | master->busy = false; | |
602 | ||
603 | init_kthread_worker(&master->kworker); | |
604 | master->kworker_task = kthread_run(kthread_worker_fn, | |
605 | &master->kworker, | |
606 | dev_name(&master->dev)); | |
607 | if (IS_ERR(master->kworker_task)) { | |
608 | dev_err(&master->dev, "failed to create message pump task\n"); | |
609 | return -ENOMEM; | |
610 | } | |
611 | init_kthread_work(&master->pump_messages, spi_pump_messages); | |
612 | ||
613 | /* | |
614 | * Master config will indicate if this controller should run the | |
615 | * message pump with high (realtime) priority to reduce the transfer | |
616 | * latency on the bus by minimising the delay between a transfer | |
617 | * request and the scheduling of the message pump thread. Without this | |
618 | * setting the message pump thread will remain at default priority. | |
619 | */ | |
620 | if (master->rt) { | |
621 | dev_info(&master->dev, | |
622 | "will run message pump with realtime priority\n"); | |
623 | sched_setscheduler(master->kworker_task, SCHED_FIFO, ¶m); | |
624 | } | |
625 | ||
626 | return 0; | |
627 | } | |
628 | ||
629 | /** | |
630 | * spi_get_next_queued_message() - called by driver to check for queued | |
631 | * messages | |
632 | * @master: the master to check for queued messages | |
633 | * | |
634 | * If there are more messages in the queue, the next message is returned from | |
635 | * this call. | |
636 | */ | |
637 | struct spi_message *spi_get_next_queued_message(struct spi_master *master) | |
638 | { | |
639 | struct spi_message *next; | |
640 | unsigned long flags; | |
641 | ||
642 | /* get a pointer to the next message, if any */ | |
643 | spin_lock_irqsave(&master->queue_lock, flags); | |
644 | if (list_empty(&master->queue)) | |
645 | next = NULL; | |
646 | else | |
647 | next = list_entry(master->queue.next, | |
648 | struct spi_message, queue); | |
649 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
650 | ||
651 | return next; | |
652 | } | |
653 | EXPORT_SYMBOL_GPL(spi_get_next_queued_message); | |
654 | ||
655 | /** | |
656 | * spi_finalize_current_message() - the current message is complete | |
657 | * @master: the master to return the message to | |
658 | * | |
659 | * Called by the driver to notify the core that the message in the front of the | |
660 | * queue is complete and can be removed from the queue. | |
661 | */ | |
662 | void spi_finalize_current_message(struct spi_master *master) | |
663 | { | |
664 | struct spi_message *mesg; | |
665 | unsigned long flags; | |
666 | ||
667 | spin_lock_irqsave(&master->queue_lock, flags); | |
668 | mesg = master->cur_msg; | |
669 | master->cur_msg = NULL; | |
670 | ||
671 | queue_kthread_work(&master->kworker, &master->pump_messages); | |
672 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
673 | ||
674 | mesg->state = NULL; | |
675 | if (mesg->complete) | |
676 | mesg->complete(mesg->context); | |
677 | } | |
678 | EXPORT_SYMBOL_GPL(spi_finalize_current_message); | |
679 | ||
680 | static int spi_start_queue(struct spi_master *master) | |
681 | { | |
682 | unsigned long flags; | |
683 | ||
684 | spin_lock_irqsave(&master->queue_lock, flags); | |
685 | ||
686 | if (master->running || master->busy) { | |
687 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
688 | return -EBUSY; | |
689 | } | |
690 | ||
691 | master->running = true; | |
692 | master->cur_msg = NULL; | |
693 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
694 | ||
695 | queue_kthread_work(&master->kworker, &master->pump_messages); | |
696 | ||
697 | return 0; | |
698 | } | |
699 | ||
700 | static int spi_stop_queue(struct spi_master *master) | |
701 | { | |
702 | unsigned long flags; | |
703 | unsigned limit = 500; | |
704 | int ret = 0; | |
705 | ||
706 | spin_lock_irqsave(&master->queue_lock, flags); | |
707 | ||
708 | /* | |
709 | * This is a bit lame, but is optimized for the common execution path. | |
710 | * A wait_queue on the master->busy could be used, but then the common | |
711 | * execution path (pump_messages) would be required to call wake_up or | |
712 | * friends on every SPI message. Do this instead. | |
713 | */ | |
714 | while ((!list_empty(&master->queue) || master->busy) && limit--) { | |
715 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
716 | msleep(10); | |
717 | spin_lock_irqsave(&master->queue_lock, flags); | |
718 | } | |
719 | ||
720 | if (!list_empty(&master->queue) || master->busy) | |
721 | ret = -EBUSY; | |
722 | else | |
723 | master->running = false; | |
724 | ||
725 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
726 | ||
727 | if (ret) { | |
728 | dev_warn(&master->dev, | |
729 | "could not stop message queue\n"); | |
730 | return ret; | |
731 | } | |
732 | return ret; | |
733 | } | |
734 | ||
735 | static int spi_destroy_queue(struct spi_master *master) | |
736 | { | |
737 | int ret; | |
738 | ||
739 | ret = spi_stop_queue(master); | |
740 | ||
741 | /* | |
742 | * flush_kthread_worker will block until all work is done. | |
743 | * If the reason that stop_queue timed out is that the work will never | |
744 | * finish, then it does no good to call flush/stop thread, so | |
745 | * return anyway. | |
746 | */ | |
747 | if (ret) { | |
748 | dev_err(&master->dev, "problem destroying queue\n"); | |
749 | return ret; | |
750 | } | |
751 | ||
752 | flush_kthread_worker(&master->kworker); | |
753 | kthread_stop(master->kworker_task); | |
754 | ||
755 | return 0; | |
756 | } | |
757 | ||
758 | /** | |
759 | * spi_queued_transfer - transfer function for queued transfers | |
760 | * @spi: spi device which is requesting transfer | |
761 | * @msg: spi message which is to handled is queued to driver queue | |
762 | */ | |
763 | static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg) | |
764 | { | |
765 | struct spi_master *master = spi->master; | |
766 | unsigned long flags; | |
767 | ||
768 | spin_lock_irqsave(&master->queue_lock, flags); | |
769 | ||
770 | if (!master->running) { | |
771 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
772 | return -ESHUTDOWN; | |
773 | } | |
774 | msg->actual_length = 0; | |
775 | msg->status = -EINPROGRESS; | |
776 | ||
777 | list_add_tail(&msg->queue, &master->queue); | |
778 | if (master->running && !master->busy) | |
779 | queue_kthread_work(&master->kworker, &master->pump_messages); | |
780 | ||
781 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
782 | return 0; | |
783 | } | |
784 | ||
785 | static int spi_master_initialize_queue(struct spi_master *master) | |
786 | { | |
787 | int ret; | |
788 | ||
789 | master->queued = true; | |
790 | master->transfer = spi_queued_transfer; | |
791 | ||
792 | /* Initialize and start queue */ | |
793 | ret = spi_init_queue(master); | |
794 | if (ret) { | |
795 | dev_err(&master->dev, "problem initializing queue\n"); | |
796 | goto err_init_queue; | |
797 | } | |
798 | ret = spi_start_queue(master); | |
799 | if (ret) { | |
800 | dev_err(&master->dev, "problem starting queue\n"); | |
801 | goto err_start_queue; | |
802 | } | |
803 | ||
804 | return 0; | |
805 | ||
806 | err_start_queue: | |
807 | err_init_queue: | |
808 | spi_destroy_queue(master); | |
809 | return ret; | |
810 | } | |
811 | ||
812 | /*-------------------------------------------------------------------------*/ | |
813 | ||
7cb94361 | 814 | #if defined(CONFIG_OF) |
d57a4282 GL |
815 | /** |
816 | * of_register_spi_devices() - Register child devices onto the SPI bus | |
817 | * @master: Pointer to spi_master device | |
818 | * | |
819 | * Registers an spi_device for each child node of master node which has a 'reg' | |
820 | * property. | |
821 | */ | |
822 | static void of_register_spi_devices(struct spi_master *master) | |
823 | { | |
824 | struct spi_device *spi; | |
825 | struct device_node *nc; | |
826 | const __be32 *prop; | |
cb71941a | 827 | char modalias[SPI_NAME_SIZE + 4]; |
d57a4282 GL |
828 | int rc; |
829 | int len; | |
830 | ||
831 | if (!master->dev.of_node) | |
832 | return; | |
833 | ||
f3b6159e | 834 | for_each_available_child_of_node(master->dev.of_node, nc) { |
d57a4282 GL |
835 | /* Alloc an spi_device */ |
836 | spi = spi_alloc_device(master); | |
837 | if (!spi) { | |
838 | dev_err(&master->dev, "spi_device alloc error for %s\n", | |
839 | nc->full_name); | |
840 | spi_dev_put(spi); | |
841 | continue; | |
842 | } | |
843 | ||
844 | /* Select device driver */ | |
845 | if (of_modalias_node(nc, spi->modalias, | |
846 | sizeof(spi->modalias)) < 0) { | |
847 | dev_err(&master->dev, "cannot find modalias for %s\n", | |
848 | nc->full_name); | |
849 | spi_dev_put(spi); | |
850 | continue; | |
851 | } | |
852 | ||
853 | /* Device address */ | |
854 | prop = of_get_property(nc, "reg", &len); | |
855 | if (!prop || len < sizeof(*prop)) { | |
856 | dev_err(&master->dev, "%s has no 'reg' property\n", | |
857 | nc->full_name); | |
858 | spi_dev_put(spi); | |
859 | continue; | |
860 | } | |
861 | spi->chip_select = be32_to_cpup(prop); | |
862 | ||
863 | /* Mode (clock phase/polarity/etc.) */ | |
864 | if (of_find_property(nc, "spi-cpha", NULL)) | |
865 | spi->mode |= SPI_CPHA; | |
866 | if (of_find_property(nc, "spi-cpol", NULL)) | |
867 | spi->mode |= SPI_CPOL; | |
868 | if (of_find_property(nc, "spi-cs-high", NULL)) | |
869 | spi->mode |= SPI_CS_HIGH; | |
c20151df LPC |
870 | if (of_find_property(nc, "spi-3wire", NULL)) |
871 | spi->mode |= SPI_3WIRE; | |
d57a4282 GL |
872 | |
873 | /* Device speed */ | |
874 | prop = of_get_property(nc, "spi-max-frequency", &len); | |
875 | if (!prop || len < sizeof(*prop)) { | |
876 | dev_err(&master->dev, "%s has no 'spi-max-frequency' property\n", | |
877 | nc->full_name); | |
878 | spi_dev_put(spi); | |
879 | continue; | |
880 | } | |
881 | spi->max_speed_hz = be32_to_cpup(prop); | |
882 | ||
883 | /* IRQ */ | |
884 | spi->irq = irq_of_parse_and_map(nc, 0); | |
885 | ||
886 | /* Store a pointer to the node in the device structure */ | |
887 | of_node_get(nc); | |
888 | spi->dev.of_node = nc; | |
889 | ||
890 | /* Register the new device */ | |
cb71941a DD |
891 | snprintf(modalias, sizeof(modalias), "%s%s", SPI_MODULE_PREFIX, |
892 | spi->modalias); | |
893 | request_module(modalias); | |
d57a4282 GL |
894 | rc = spi_add_device(spi); |
895 | if (rc) { | |
896 | dev_err(&master->dev, "spi_device register error %s\n", | |
897 | nc->full_name); | |
898 | spi_dev_put(spi); | |
899 | } | |
900 | ||
901 | } | |
902 | } | |
903 | #else | |
904 | static void of_register_spi_devices(struct spi_master *master) { } | |
905 | #endif | |
906 | ||
64bee4d2 MW |
907 | #ifdef CONFIG_ACPI |
908 | static int acpi_spi_add_resource(struct acpi_resource *ares, void *data) | |
909 | { | |
910 | struct spi_device *spi = data; | |
911 | ||
912 | if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) { | |
913 | struct acpi_resource_spi_serialbus *sb; | |
914 | ||
915 | sb = &ares->data.spi_serial_bus; | |
916 | if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) { | |
917 | spi->chip_select = sb->device_selection; | |
918 | spi->max_speed_hz = sb->connection_speed; | |
919 | ||
920 | if (sb->clock_phase == ACPI_SPI_SECOND_PHASE) | |
921 | spi->mode |= SPI_CPHA; | |
922 | if (sb->clock_polarity == ACPI_SPI_START_HIGH) | |
923 | spi->mode |= SPI_CPOL; | |
924 | if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH) | |
925 | spi->mode |= SPI_CS_HIGH; | |
926 | } | |
927 | } else if (spi->irq < 0) { | |
928 | struct resource r; | |
929 | ||
930 | if (acpi_dev_resource_interrupt(ares, 0, &r)) | |
931 | spi->irq = r.start; | |
932 | } | |
933 | ||
934 | /* Always tell the ACPI core to skip this resource */ | |
935 | return 1; | |
936 | } | |
937 | ||
938 | static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level, | |
939 | void *data, void **return_value) | |
940 | { | |
941 | struct spi_master *master = data; | |
942 | struct list_head resource_list; | |
943 | struct acpi_device *adev; | |
944 | struct spi_device *spi; | |
945 | int ret; | |
946 | ||
947 | if (acpi_bus_get_device(handle, &adev)) | |
948 | return AE_OK; | |
949 | if (acpi_bus_get_status(adev) || !adev->status.present) | |
950 | return AE_OK; | |
951 | ||
952 | spi = spi_alloc_device(master); | |
953 | if (!spi) { | |
954 | dev_err(&master->dev, "failed to allocate SPI device for %s\n", | |
955 | dev_name(&adev->dev)); | |
956 | return AE_NO_MEMORY; | |
957 | } | |
958 | ||
959 | ACPI_HANDLE_SET(&spi->dev, handle); | |
960 | spi->irq = -1; | |
961 | ||
962 | INIT_LIST_HEAD(&resource_list); | |
963 | ret = acpi_dev_get_resources(adev, &resource_list, | |
964 | acpi_spi_add_resource, spi); | |
965 | acpi_dev_free_resource_list(&resource_list); | |
966 | ||
967 | if (ret < 0 || !spi->max_speed_hz) { | |
968 | spi_dev_put(spi); | |
969 | return AE_OK; | |
970 | } | |
971 | ||
972 | strlcpy(spi->modalias, dev_name(&adev->dev), sizeof(spi->modalias)); | |
973 | if (spi_add_device(spi)) { | |
974 | dev_err(&master->dev, "failed to add SPI device %s from ACPI\n", | |
975 | dev_name(&adev->dev)); | |
976 | spi_dev_put(spi); | |
977 | } | |
978 | ||
979 | return AE_OK; | |
980 | } | |
981 | ||
982 | static void acpi_register_spi_devices(struct spi_master *master) | |
983 | { | |
984 | acpi_status status; | |
985 | acpi_handle handle; | |
986 | ||
987 | handle = ACPI_HANDLE(&master->dev); | |
988 | if (!handle) | |
989 | return; | |
990 | ||
991 | status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1, | |
992 | acpi_spi_add_device, NULL, | |
993 | master, NULL); | |
994 | if (ACPI_FAILURE(status)) | |
995 | dev_warn(&master->dev, "failed to enumerate SPI slaves\n"); | |
996 | } | |
997 | #else | |
998 | static inline void acpi_register_spi_devices(struct spi_master *master) {} | |
999 | #endif /* CONFIG_ACPI */ | |
1000 | ||
49dce689 | 1001 | static void spi_master_release(struct device *dev) |
8ae12a0d DB |
1002 | { |
1003 | struct spi_master *master; | |
1004 | ||
49dce689 | 1005 | master = container_of(dev, struct spi_master, dev); |
8ae12a0d DB |
1006 | kfree(master); |
1007 | } | |
1008 | ||
1009 | static struct class spi_master_class = { | |
1010 | .name = "spi_master", | |
1011 | .owner = THIS_MODULE, | |
49dce689 | 1012 | .dev_release = spi_master_release, |
8ae12a0d DB |
1013 | }; |
1014 | ||
1015 | ||
ffbbdd21 | 1016 | |
8ae12a0d DB |
1017 | /** |
1018 | * spi_alloc_master - allocate SPI master controller | |
1019 | * @dev: the controller, possibly using the platform_bus | |
33e34dc6 | 1020 | * @size: how much zeroed driver-private data to allocate; the pointer to this |
49dce689 | 1021 | * memory is in the driver_data field of the returned device, |
0c868461 | 1022 | * accessible with spi_master_get_devdata(). |
33e34dc6 | 1023 | * Context: can sleep |
8ae12a0d DB |
1024 | * |
1025 | * This call is used only by SPI master controller drivers, which are the | |
1026 | * only ones directly touching chip registers. It's how they allocate | |
ba1a0513 | 1027 | * an spi_master structure, prior to calling spi_register_master(). |
8ae12a0d DB |
1028 | * |
1029 | * This must be called from context that can sleep. It returns the SPI | |
1030 | * master structure on success, else NULL. | |
1031 | * | |
1032 | * The caller is responsible for assigning the bus number and initializing | |
ba1a0513 | 1033 | * the master's methods before calling spi_register_master(); and (after errors |
eb4af0f5 UKK |
1034 | * adding the device) calling spi_master_put() and kfree() to prevent a memory |
1035 | * leak. | |
8ae12a0d | 1036 | */ |
e9d5a461 | 1037 | struct spi_master *spi_alloc_master(struct device *dev, unsigned size) |
8ae12a0d DB |
1038 | { |
1039 | struct spi_master *master; | |
1040 | ||
0c868461 DB |
1041 | if (!dev) |
1042 | return NULL; | |
1043 | ||
e94b1766 | 1044 | master = kzalloc(size + sizeof *master, GFP_KERNEL); |
8ae12a0d DB |
1045 | if (!master) |
1046 | return NULL; | |
1047 | ||
49dce689 | 1048 | device_initialize(&master->dev); |
1e8a52e1 GL |
1049 | master->bus_num = -1; |
1050 | master->num_chipselect = 1; | |
49dce689 TJ |
1051 | master->dev.class = &spi_master_class; |
1052 | master->dev.parent = get_device(dev); | |
0c868461 | 1053 | spi_master_set_devdata(master, &master[1]); |
8ae12a0d DB |
1054 | |
1055 | return master; | |
1056 | } | |
1057 | EXPORT_SYMBOL_GPL(spi_alloc_master); | |
1058 | ||
74317984 JCPV |
1059 | #ifdef CONFIG_OF |
1060 | static int of_spi_register_master(struct spi_master *master) | |
1061 | { | |
e80beb27 | 1062 | int nb, i, *cs; |
74317984 JCPV |
1063 | struct device_node *np = master->dev.of_node; |
1064 | ||
1065 | if (!np) | |
1066 | return 0; | |
1067 | ||
1068 | nb = of_gpio_named_count(np, "cs-gpios"); | |
e80beb27 | 1069 | master->num_chipselect = max(nb, (int)master->num_chipselect); |
74317984 JCPV |
1070 | |
1071 | if (nb < 1) | |
1072 | return 0; | |
1073 | ||
1074 | cs = devm_kzalloc(&master->dev, | |
1075 | sizeof(int) * master->num_chipselect, | |
1076 | GFP_KERNEL); | |
1077 | master->cs_gpios = cs; | |
1078 | ||
1079 | if (!master->cs_gpios) | |
1080 | return -ENOMEM; | |
1081 | ||
0da83bb1 AL |
1082 | for (i = 0; i < master->num_chipselect; i++) |
1083 | cs[i] = -EINVAL; | |
74317984 JCPV |
1084 | |
1085 | for (i = 0; i < nb; i++) | |
1086 | cs[i] = of_get_named_gpio(np, "cs-gpios", i); | |
1087 | ||
1088 | return 0; | |
1089 | } | |
1090 | #else | |
1091 | static int of_spi_register_master(struct spi_master *master) | |
1092 | { | |
1093 | return 0; | |
1094 | } | |
1095 | #endif | |
1096 | ||
8ae12a0d DB |
1097 | /** |
1098 | * spi_register_master - register SPI master controller | |
1099 | * @master: initialized master, originally from spi_alloc_master() | |
33e34dc6 | 1100 | * Context: can sleep |
8ae12a0d DB |
1101 | * |
1102 | * SPI master controllers connect to their drivers using some non-SPI bus, | |
1103 | * such as the platform bus. The final stage of probe() in that code | |
1104 | * includes calling spi_register_master() to hook up to this SPI bus glue. | |
1105 | * | |
1106 | * SPI controllers use board specific (often SOC specific) bus numbers, | |
1107 | * and board-specific addressing for SPI devices combines those numbers | |
1108 | * with chip select numbers. Since SPI does not directly support dynamic | |
1109 | * device identification, boards need configuration tables telling which | |
1110 | * chip is at which address. | |
1111 | * | |
1112 | * This must be called from context that can sleep. It returns zero on | |
1113 | * success, else a negative error code (dropping the master's refcount). | |
0c868461 DB |
1114 | * After a successful return, the caller is responsible for calling |
1115 | * spi_unregister_master(). | |
8ae12a0d | 1116 | */ |
e9d5a461 | 1117 | int spi_register_master(struct spi_master *master) |
8ae12a0d | 1118 | { |
e44a45ae | 1119 | static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1); |
49dce689 | 1120 | struct device *dev = master->dev.parent; |
2b9603a0 | 1121 | struct boardinfo *bi; |
8ae12a0d DB |
1122 | int status = -ENODEV; |
1123 | int dynamic = 0; | |
1124 | ||
0c868461 DB |
1125 | if (!dev) |
1126 | return -ENODEV; | |
1127 | ||
74317984 JCPV |
1128 | status = of_spi_register_master(master); |
1129 | if (status) | |
1130 | return status; | |
1131 | ||
082c8cb4 DB |
1132 | /* even if it's just one always-selected device, there must |
1133 | * be at least one chipselect | |
1134 | */ | |
1135 | if (master->num_chipselect == 0) | |
1136 | return -EINVAL; | |
1137 | ||
bb29785e GL |
1138 | if ((master->bus_num < 0) && master->dev.of_node) |
1139 | master->bus_num = of_alias_get_id(master->dev.of_node, "spi"); | |
1140 | ||
8ae12a0d | 1141 | /* convention: dynamically assigned bus IDs count down from the max */ |
a020ed75 | 1142 | if (master->bus_num < 0) { |
082c8cb4 DB |
1143 | /* FIXME switch to an IDR based scheme, something like |
1144 | * I2C now uses, so we can't run out of "dynamic" IDs | |
1145 | */ | |
8ae12a0d | 1146 | master->bus_num = atomic_dec_return(&dyn_bus_id); |
b885244e | 1147 | dynamic = 1; |
8ae12a0d DB |
1148 | } |
1149 | ||
cf32b71e ES |
1150 | spin_lock_init(&master->bus_lock_spinlock); |
1151 | mutex_init(&master->bus_lock_mutex); | |
1152 | master->bus_lock_flag = 0; | |
1153 | ||
8ae12a0d DB |
1154 | /* register the device, then userspace will see it. |
1155 | * registration fails if the bus ID is in use. | |
1156 | */ | |
35f74fca | 1157 | dev_set_name(&master->dev, "spi%u", master->bus_num); |
49dce689 | 1158 | status = device_add(&master->dev); |
b885244e | 1159 | if (status < 0) |
8ae12a0d | 1160 | goto done; |
35f74fca | 1161 | dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev), |
8ae12a0d DB |
1162 | dynamic ? " (dynamic)" : ""); |
1163 | ||
ffbbdd21 LW |
1164 | /* If we're using a queued driver, start the queue */ |
1165 | if (master->transfer) | |
1166 | dev_info(dev, "master is unqueued, this is deprecated\n"); | |
1167 | else { | |
1168 | status = spi_master_initialize_queue(master); | |
1169 | if (status) { | |
1170 | device_unregister(&master->dev); | |
1171 | goto done; | |
1172 | } | |
1173 | } | |
1174 | ||
2b9603a0 FT |
1175 | mutex_lock(&board_lock); |
1176 | list_add_tail(&master->list, &spi_master_list); | |
1177 | list_for_each_entry(bi, &board_list, list) | |
1178 | spi_match_master_to_boardinfo(master, &bi->board_info); | |
1179 | mutex_unlock(&board_lock); | |
1180 | ||
64bee4d2 | 1181 | /* Register devices from the device tree and ACPI */ |
12b15e83 | 1182 | of_register_spi_devices(master); |
64bee4d2 | 1183 | acpi_register_spi_devices(master); |
8ae12a0d DB |
1184 | done: |
1185 | return status; | |
1186 | } | |
1187 | EXPORT_SYMBOL_GPL(spi_register_master); | |
1188 | ||
34860089 | 1189 | static int __unregister(struct device *dev, void *null) |
8ae12a0d | 1190 | { |
34860089 | 1191 | spi_unregister_device(to_spi_device(dev)); |
8ae12a0d DB |
1192 | return 0; |
1193 | } | |
1194 | ||
1195 | /** | |
1196 | * spi_unregister_master - unregister SPI master controller | |
1197 | * @master: the master being unregistered | |
33e34dc6 | 1198 | * Context: can sleep |
8ae12a0d DB |
1199 | * |
1200 | * This call is used only by SPI master controller drivers, which are the | |
1201 | * only ones directly touching chip registers. | |
1202 | * | |
1203 | * This must be called from context that can sleep. | |
1204 | */ | |
1205 | void spi_unregister_master(struct spi_master *master) | |
1206 | { | |
89fc9a1a JG |
1207 | int dummy; |
1208 | ||
ffbbdd21 LW |
1209 | if (master->queued) { |
1210 | if (spi_destroy_queue(master)) | |
1211 | dev_err(&master->dev, "queue remove failed\n"); | |
1212 | } | |
1213 | ||
2b9603a0 FT |
1214 | mutex_lock(&board_lock); |
1215 | list_del(&master->list); | |
1216 | mutex_unlock(&board_lock); | |
1217 | ||
97dbf37d | 1218 | dummy = device_for_each_child(&master->dev, NULL, __unregister); |
49dce689 | 1219 | device_unregister(&master->dev); |
8ae12a0d DB |
1220 | } |
1221 | EXPORT_SYMBOL_GPL(spi_unregister_master); | |
1222 | ||
ffbbdd21 LW |
1223 | int spi_master_suspend(struct spi_master *master) |
1224 | { | |
1225 | int ret; | |
1226 | ||
1227 | /* Basically no-ops for non-queued masters */ | |
1228 | if (!master->queued) | |
1229 | return 0; | |
1230 | ||
1231 | ret = spi_stop_queue(master); | |
1232 | if (ret) | |
1233 | dev_err(&master->dev, "queue stop failed\n"); | |
1234 | ||
1235 | return ret; | |
1236 | } | |
1237 | EXPORT_SYMBOL_GPL(spi_master_suspend); | |
1238 | ||
1239 | int spi_master_resume(struct spi_master *master) | |
1240 | { | |
1241 | int ret; | |
1242 | ||
1243 | if (!master->queued) | |
1244 | return 0; | |
1245 | ||
1246 | ret = spi_start_queue(master); | |
1247 | if (ret) | |
1248 | dev_err(&master->dev, "queue restart failed\n"); | |
1249 | ||
1250 | return ret; | |
1251 | } | |
1252 | EXPORT_SYMBOL_GPL(spi_master_resume); | |
1253 | ||
9f3b795a | 1254 | static int __spi_master_match(struct device *dev, const void *data) |
5ed2c832 DY |
1255 | { |
1256 | struct spi_master *m; | |
9f3b795a | 1257 | const u16 *bus_num = data; |
5ed2c832 DY |
1258 | |
1259 | m = container_of(dev, struct spi_master, dev); | |
1260 | return m->bus_num == *bus_num; | |
1261 | } | |
1262 | ||
8ae12a0d DB |
1263 | /** |
1264 | * spi_busnum_to_master - look up master associated with bus_num | |
1265 | * @bus_num: the master's bus number | |
33e34dc6 | 1266 | * Context: can sleep |
8ae12a0d DB |
1267 | * |
1268 | * This call may be used with devices that are registered after | |
1269 | * arch init time. It returns a refcounted pointer to the relevant | |
1270 | * spi_master (which the caller must release), or NULL if there is | |
1271 | * no such master registered. | |
1272 | */ | |
1273 | struct spi_master *spi_busnum_to_master(u16 bus_num) | |
1274 | { | |
49dce689 | 1275 | struct device *dev; |
1e9a51dc | 1276 | struct spi_master *master = NULL; |
5ed2c832 | 1277 | |
695794ae | 1278 | dev = class_find_device(&spi_master_class, NULL, &bus_num, |
5ed2c832 DY |
1279 | __spi_master_match); |
1280 | if (dev) | |
1281 | master = container_of(dev, struct spi_master, dev); | |
1282 | /* reference got in class_find_device */ | |
1e9a51dc | 1283 | return master; |
8ae12a0d DB |
1284 | } |
1285 | EXPORT_SYMBOL_GPL(spi_busnum_to_master); | |
1286 | ||
1287 | ||
1288 | /*-------------------------------------------------------------------------*/ | |
1289 | ||
7d077197 DB |
1290 | /* Core methods for SPI master protocol drivers. Some of the |
1291 | * other core methods are currently defined as inline functions. | |
1292 | */ | |
1293 | ||
1294 | /** | |
1295 | * spi_setup - setup SPI mode and clock rate | |
1296 | * @spi: the device whose settings are being modified | |
1297 | * Context: can sleep, and no requests are queued to the device | |
1298 | * | |
1299 | * SPI protocol drivers may need to update the transfer mode if the | |
1300 | * device doesn't work with its default. They may likewise need | |
1301 | * to update clock rates or word sizes from initial values. This function | |
1302 | * changes those settings, and must be called from a context that can sleep. | |
1303 | * Except for SPI_CS_HIGH, which takes effect immediately, the changes take | |
1304 | * effect the next time the device is selected and data is transferred to | |
1305 | * or from it. When this function returns, the spi device is deselected. | |
1306 | * | |
1307 | * Note that this call will fail if the protocol driver specifies an option | |
1308 | * that the underlying controller or its driver does not support. For | |
1309 | * example, not all hardware supports wire transfers using nine bit words, | |
1310 | * LSB-first wire encoding, or active-high chipselects. | |
1311 | */ | |
1312 | int spi_setup(struct spi_device *spi) | |
1313 | { | |
e7db06b5 | 1314 | unsigned bad_bits; |
caae070c | 1315 | int status = 0; |
7d077197 | 1316 | |
e7db06b5 DB |
1317 | /* help drivers fail *cleanly* when they need options |
1318 | * that aren't supported with their current master | |
1319 | */ | |
1320 | bad_bits = spi->mode & ~spi->master->mode_bits; | |
1321 | if (bad_bits) { | |
eb288a1f | 1322 | dev_err(&spi->dev, "setup: unsupported mode bits %x\n", |
e7db06b5 DB |
1323 | bad_bits); |
1324 | return -EINVAL; | |
1325 | } | |
1326 | ||
7d077197 DB |
1327 | if (!spi->bits_per_word) |
1328 | spi->bits_per_word = 8; | |
1329 | ||
caae070c LD |
1330 | if (spi->master->setup) |
1331 | status = spi->master->setup(spi); | |
7d077197 DB |
1332 | |
1333 | dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s" | |
1334 | "%u bits/w, %u Hz max --> %d\n", | |
1335 | (int) (spi->mode & (SPI_CPOL | SPI_CPHA)), | |
1336 | (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "", | |
1337 | (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "", | |
1338 | (spi->mode & SPI_3WIRE) ? "3wire, " : "", | |
1339 | (spi->mode & SPI_LOOP) ? "loopback, " : "", | |
1340 | spi->bits_per_word, spi->max_speed_hz, | |
1341 | status); | |
1342 | ||
1343 | return status; | |
1344 | } | |
1345 | EXPORT_SYMBOL_GPL(spi_setup); | |
1346 | ||
cf32b71e ES |
1347 | static int __spi_async(struct spi_device *spi, struct spi_message *message) |
1348 | { | |
1349 | struct spi_master *master = spi->master; | |
e6811d1d | 1350 | struct spi_transfer *xfer; |
cf32b71e ES |
1351 | |
1352 | /* Half-duplex links include original MicroWire, and ones with | |
1353 | * only one data pin like SPI_3WIRE (switches direction) or where | |
1354 | * either MOSI or MISO is missing. They can also be caused by | |
1355 | * software limitations. | |
1356 | */ | |
1357 | if ((master->flags & SPI_MASTER_HALF_DUPLEX) | |
1358 | || (spi->mode & SPI_3WIRE)) { | |
cf32b71e ES |
1359 | unsigned flags = master->flags; |
1360 | ||
1361 | list_for_each_entry(xfer, &message->transfers, transfer_list) { | |
1362 | if (xfer->rx_buf && xfer->tx_buf) | |
1363 | return -EINVAL; | |
1364 | if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf) | |
1365 | return -EINVAL; | |
1366 | if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf) | |
1367 | return -EINVAL; | |
1368 | } | |
1369 | } | |
1370 | ||
e6811d1d | 1371 | /** |
059b8ffe LD |
1372 | * Set transfer bits_per_word and max speed as spi device default if |
1373 | * it is not set for this transfer. | |
e6811d1d LD |
1374 | */ |
1375 | list_for_each_entry(xfer, &message->transfers, transfer_list) { | |
1376 | if (!xfer->bits_per_word) | |
1377 | xfer->bits_per_word = spi->bits_per_word; | |
059b8ffe LD |
1378 | if (!xfer->speed_hz) |
1379 | xfer->speed_hz = spi->max_speed_hz; | |
e6811d1d LD |
1380 | } |
1381 | ||
cf32b71e ES |
1382 | message->spi = spi; |
1383 | message->status = -EINPROGRESS; | |
1384 | return master->transfer(spi, message); | |
1385 | } | |
1386 | ||
568d0697 DB |
1387 | /** |
1388 | * spi_async - asynchronous SPI transfer | |
1389 | * @spi: device with which data will be exchanged | |
1390 | * @message: describes the data transfers, including completion callback | |
1391 | * Context: any (irqs may be blocked, etc) | |
1392 | * | |
1393 | * This call may be used in_irq and other contexts which can't sleep, | |
1394 | * as well as from task contexts which can sleep. | |
1395 | * | |
1396 | * The completion callback is invoked in a context which can't sleep. | |
1397 | * Before that invocation, the value of message->status is undefined. | |
1398 | * When the callback is issued, message->status holds either zero (to | |
1399 | * indicate complete success) or a negative error code. After that | |
1400 | * callback returns, the driver which issued the transfer request may | |
1401 | * deallocate the associated memory; it's no longer in use by any SPI | |
1402 | * core or controller driver code. | |
1403 | * | |
1404 | * Note that although all messages to a spi_device are handled in | |
1405 | * FIFO order, messages may go to different devices in other orders. | |
1406 | * Some device might be higher priority, or have various "hard" access | |
1407 | * time requirements, for example. | |
1408 | * | |
1409 | * On detection of any fault during the transfer, processing of | |
1410 | * the entire message is aborted, and the device is deselected. | |
1411 | * Until returning from the associated message completion callback, | |
1412 | * no other spi_message queued to that device will be processed. | |
1413 | * (This rule applies equally to all the synchronous transfer calls, | |
1414 | * which are wrappers around this core asynchronous primitive.) | |
1415 | */ | |
1416 | int spi_async(struct spi_device *spi, struct spi_message *message) | |
1417 | { | |
1418 | struct spi_master *master = spi->master; | |
cf32b71e ES |
1419 | int ret; |
1420 | unsigned long flags; | |
568d0697 | 1421 | |
cf32b71e | 1422 | spin_lock_irqsave(&master->bus_lock_spinlock, flags); |
568d0697 | 1423 | |
cf32b71e ES |
1424 | if (master->bus_lock_flag) |
1425 | ret = -EBUSY; | |
1426 | else | |
1427 | ret = __spi_async(spi, message); | |
568d0697 | 1428 | |
cf32b71e ES |
1429 | spin_unlock_irqrestore(&master->bus_lock_spinlock, flags); |
1430 | ||
1431 | return ret; | |
568d0697 DB |
1432 | } |
1433 | EXPORT_SYMBOL_GPL(spi_async); | |
1434 | ||
cf32b71e ES |
1435 | /** |
1436 | * spi_async_locked - version of spi_async with exclusive bus usage | |
1437 | * @spi: device with which data will be exchanged | |
1438 | * @message: describes the data transfers, including completion callback | |
1439 | * Context: any (irqs may be blocked, etc) | |
1440 | * | |
1441 | * This call may be used in_irq and other contexts which can't sleep, | |
1442 | * as well as from task contexts which can sleep. | |
1443 | * | |
1444 | * The completion callback is invoked in a context which can't sleep. | |
1445 | * Before that invocation, the value of message->status is undefined. | |
1446 | * When the callback is issued, message->status holds either zero (to | |
1447 | * indicate complete success) or a negative error code. After that | |
1448 | * callback returns, the driver which issued the transfer request may | |
1449 | * deallocate the associated memory; it's no longer in use by any SPI | |
1450 | * core or controller driver code. | |
1451 | * | |
1452 | * Note that although all messages to a spi_device are handled in | |
1453 | * FIFO order, messages may go to different devices in other orders. | |
1454 | * Some device might be higher priority, or have various "hard" access | |
1455 | * time requirements, for example. | |
1456 | * | |
1457 | * On detection of any fault during the transfer, processing of | |
1458 | * the entire message is aborted, and the device is deselected. | |
1459 | * Until returning from the associated message completion callback, | |
1460 | * no other spi_message queued to that device will be processed. | |
1461 | * (This rule applies equally to all the synchronous transfer calls, | |
1462 | * which are wrappers around this core asynchronous primitive.) | |
1463 | */ | |
1464 | int spi_async_locked(struct spi_device *spi, struct spi_message *message) | |
1465 | { | |
1466 | struct spi_master *master = spi->master; | |
1467 | int ret; | |
1468 | unsigned long flags; | |
1469 | ||
1470 | spin_lock_irqsave(&master->bus_lock_spinlock, flags); | |
1471 | ||
1472 | ret = __spi_async(spi, message); | |
1473 | ||
1474 | spin_unlock_irqrestore(&master->bus_lock_spinlock, flags); | |
1475 | ||
1476 | return ret; | |
1477 | ||
1478 | } | |
1479 | EXPORT_SYMBOL_GPL(spi_async_locked); | |
1480 | ||
7d077197 DB |
1481 | |
1482 | /*-------------------------------------------------------------------------*/ | |
1483 | ||
1484 | /* Utility methods for SPI master protocol drivers, layered on | |
1485 | * top of the core. Some other utility methods are defined as | |
1486 | * inline functions. | |
1487 | */ | |
1488 | ||
5d870c8e AM |
1489 | static void spi_complete(void *arg) |
1490 | { | |
1491 | complete(arg); | |
1492 | } | |
1493 | ||
cf32b71e ES |
1494 | static int __spi_sync(struct spi_device *spi, struct spi_message *message, |
1495 | int bus_locked) | |
1496 | { | |
1497 | DECLARE_COMPLETION_ONSTACK(done); | |
1498 | int status; | |
1499 | struct spi_master *master = spi->master; | |
1500 | ||
1501 | message->complete = spi_complete; | |
1502 | message->context = &done; | |
1503 | ||
1504 | if (!bus_locked) | |
1505 | mutex_lock(&master->bus_lock_mutex); | |
1506 | ||
1507 | status = spi_async_locked(spi, message); | |
1508 | ||
1509 | if (!bus_locked) | |
1510 | mutex_unlock(&master->bus_lock_mutex); | |
1511 | ||
1512 | if (status == 0) { | |
1513 | wait_for_completion(&done); | |
1514 | status = message->status; | |
1515 | } | |
1516 | message->context = NULL; | |
1517 | return status; | |
1518 | } | |
1519 | ||
8ae12a0d DB |
1520 | /** |
1521 | * spi_sync - blocking/synchronous SPI data transfers | |
1522 | * @spi: device with which data will be exchanged | |
1523 | * @message: describes the data transfers | |
33e34dc6 | 1524 | * Context: can sleep |
8ae12a0d DB |
1525 | * |
1526 | * This call may only be used from a context that may sleep. The sleep | |
1527 | * is non-interruptible, and has no timeout. Low-overhead controller | |
1528 | * drivers may DMA directly into and out of the message buffers. | |
1529 | * | |
1530 | * Note that the SPI device's chip select is active during the message, | |
1531 | * and then is normally disabled between messages. Drivers for some | |
1532 | * frequently-used devices may want to minimize costs of selecting a chip, | |
1533 | * by leaving it selected in anticipation that the next message will go | |
1534 | * to the same chip. (That may increase power usage.) | |
1535 | * | |
0c868461 DB |
1536 | * Also, the caller is guaranteeing that the memory associated with the |
1537 | * message will not be freed before this call returns. | |
1538 | * | |
9b938b74 | 1539 | * It returns zero on success, else a negative error code. |
8ae12a0d DB |
1540 | */ |
1541 | int spi_sync(struct spi_device *spi, struct spi_message *message) | |
1542 | { | |
cf32b71e | 1543 | return __spi_sync(spi, message, 0); |
8ae12a0d DB |
1544 | } |
1545 | EXPORT_SYMBOL_GPL(spi_sync); | |
1546 | ||
cf32b71e ES |
1547 | /** |
1548 | * spi_sync_locked - version of spi_sync with exclusive bus usage | |
1549 | * @spi: device with which data will be exchanged | |
1550 | * @message: describes the data transfers | |
1551 | * Context: can sleep | |
1552 | * | |
1553 | * This call may only be used from a context that may sleep. The sleep | |
1554 | * is non-interruptible, and has no timeout. Low-overhead controller | |
1555 | * drivers may DMA directly into and out of the message buffers. | |
1556 | * | |
1557 | * This call should be used by drivers that require exclusive access to the | |
25985edc | 1558 | * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must |
cf32b71e ES |
1559 | * be released by a spi_bus_unlock call when the exclusive access is over. |
1560 | * | |
1561 | * It returns zero on success, else a negative error code. | |
1562 | */ | |
1563 | int spi_sync_locked(struct spi_device *spi, struct spi_message *message) | |
1564 | { | |
1565 | return __spi_sync(spi, message, 1); | |
1566 | } | |
1567 | EXPORT_SYMBOL_GPL(spi_sync_locked); | |
1568 | ||
1569 | /** | |
1570 | * spi_bus_lock - obtain a lock for exclusive SPI bus usage | |
1571 | * @master: SPI bus master that should be locked for exclusive bus access | |
1572 | * Context: can sleep | |
1573 | * | |
1574 | * This call may only be used from a context that may sleep. The sleep | |
1575 | * is non-interruptible, and has no timeout. | |
1576 | * | |
1577 | * This call should be used by drivers that require exclusive access to the | |
1578 | * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the | |
1579 | * exclusive access is over. Data transfer must be done by spi_sync_locked | |
1580 | * and spi_async_locked calls when the SPI bus lock is held. | |
1581 | * | |
1582 | * It returns zero on success, else a negative error code. | |
1583 | */ | |
1584 | int spi_bus_lock(struct spi_master *master) | |
1585 | { | |
1586 | unsigned long flags; | |
1587 | ||
1588 | mutex_lock(&master->bus_lock_mutex); | |
1589 | ||
1590 | spin_lock_irqsave(&master->bus_lock_spinlock, flags); | |
1591 | master->bus_lock_flag = 1; | |
1592 | spin_unlock_irqrestore(&master->bus_lock_spinlock, flags); | |
1593 | ||
1594 | /* mutex remains locked until spi_bus_unlock is called */ | |
1595 | ||
1596 | return 0; | |
1597 | } | |
1598 | EXPORT_SYMBOL_GPL(spi_bus_lock); | |
1599 | ||
1600 | /** | |
1601 | * spi_bus_unlock - release the lock for exclusive SPI bus usage | |
1602 | * @master: SPI bus master that was locked for exclusive bus access | |
1603 | * Context: can sleep | |
1604 | * | |
1605 | * This call may only be used from a context that may sleep. The sleep | |
1606 | * is non-interruptible, and has no timeout. | |
1607 | * | |
1608 | * This call releases an SPI bus lock previously obtained by an spi_bus_lock | |
1609 | * call. | |
1610 | * | |
1611 | * It returns zero on success, else a negative error code. | |
1612 | */ | |
1613 | int spi_bus_unlock(struct spi_master *master) | |
1614 | { | |
1615 | master->bus_lock_flag = 0; | |
1616 | ||
1617 | mutex_unlock(&master->bus_lock_mutex); | |
1618 | ||
1619 | return 0; | |
1620 | } | |
1621 | EXPORT_SYMBOL_GPL(spi_bus_unlock); | |
1622 | ||
a9948b61 DB |
1623 | /* portable code must never pass more than 32 bytes */ |
1624 | #define SPI_BUFSIZ max(32,SMP_CACHE_BYTES) | |
8ae12a0d DB |
1625 | |
1626 | static u8 *buf; | |
1627 | ||
1628 | /** | |
1629 | * spi_write_then_read - SPI synchronous write followed by read | |
1630 | * @spi: device with which data will be exchanged | |
1631 | * @txbuf: data to be written (need not be dma-safe) | |
1632 | * @n_tx: size of txbuf, in bytes | |
27570497 JP |
1633 | * @rxbuf: buffer into which data will be read (need not be dma-safe) |
1634 | * @n_rx: size of rxbuf, in bytes | |
33e34dc6 | 1635 | * Context: can sleep |
8ae12a0d DB |
1636 | * |
1637 | * This performs a half duplex MicroWire style transaction with the | |
1638 | * device, sending txbuf and then reading rxbuf. The return value | |
1639 | * is zero for success, else a negative errno status code. | |
b885244e | 1640 | * This call may only be used from a context that may sleep. |
8ae12a0d | 1641 | * |
0c868461 | 1642 | * Parameters to this routine are always copied using a small buffer; |
33e34dc6 DB |
1643 | * portable code should never use this for more than 32 bytes. |
1644 | * Performance-sensitive or bulk transfer code should instead use | |
0c868461 | 1645 | * spi_{async,sync}() calls with dma-safe buffers. |
8ae12a0d DB |
1646 | */ |
1647 | int spi_write_then_read(struct spi_device *spi, | |
0c4a1590 MB |
1648 | const void *txbuf, unsigned n_tx, |
1649 | void *rxbuf, unsigned n_rx) | |
8ae12a0d | 1650 | { |
068f4070 | 1651 | static DEFINE_MUTEX(lock); |
8ae12a0d DB |
1652 | |
1653 | int status; | |
1654 | struct spi_message message; | |
bdff549e | 1655 | struct spi_transfer x[2]; |
8ae12a0d DB |
1656 | u8 *local_buf; |
1657 | ||
b3a223ee MB |
1658 | /* Use preallocated DMA-safe buffer if we can. We can't avoid |
1659 | * copying here, (as a pure convenience thing), but we can | |
1660 | * keep heap costs out of the hot path unless someone else is | |
1661 | * using the pre-allocated buffer or the transfer is too large. | |
8ae12a0d | 1662 | */ |
b3a223ee | 1663 | if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) { |
2cd94c8a MB |
1664 | local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx), |
1665 | GFP_KERNEL | GFP_DMA); | |
b3a223ee MB |
1666 | if (!local_buf) |
1667 | return -ENOMEM; | |
1668 | } else { | |
1669 | local_buf = buf; | |
1670 | } | |
8ae12a0d | 1671 | |
8275c642 | 1672 | spi_message_init(&message); |
bdff549e DB |
1673 | memset(x, 0, sizeof x); |
1674 | if (n_tx) { | |
1675 | x[0].len = n_tx; | |
1676 | spi_message_add_tail(&x[0], &message); | |
1677 | } | |
1678 | if (n_rx) { | |
1679 | x[1].len = n_rx; | |
1680 | spi_message_add_tail(&x[1], &message); | |
1681 | } | |
8275c642 | 1682 | |
8ae12a0d | 1683 | memcpy(local_buf, txbuf, n_tx); |
bdff549e DB |
1684 | x[0].tx_buf = local_buf; |
1685 | x[1].rx_buf = local_buf + n_tx; | |
8ae12a0d DB |
1686 | |
1687 | /* do the i/o */ | |
8ae12a0d | 1688 | status = spi_sync(spi, &message); |
9b938b74 | 1689 | if (status == 0) |
bdff549e | 1690 | memcpy(rxbuf, x[1].rx_buf, n_rx); |
8ae12a0d | 1691 | |
bdff549e | 1692 | if (x[0].tx_buf == buf) |
068f4070 | 1693 | mutex_unlock(&lock); |
8ae12a0d DB |
1694 | else |
1695 | kfree(local_buf); | |
1696 | ||
1697 | return status; | |
1698 | } | |
1699 | EXPORT_SYMBOL_GPL(spi_write_then_read); | |
1700 | ||
1701 | /*-------------------------------------------------------------------------*/ | |
1702 | ||
1703 | static int __init spi_init(void) | |
1704 | { | |
b885244e DB |
1705 | int status; |
1706 | ||
e94b1766 | 1707 | buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL); |
b885244e DB |
1708 | if (!buf) { |
1709 | status = -ENOMEM; | |
1710 | goto err0; | |
1711 | } | |
1712 | ||
1713 | status = bus_register(&spi_bus_type); | |
1714 | if (status < 0) | |
1715 | goto err1; | |
8ae12a0d | 1716 | |
b885244e DB |
1717 | status = class_register(&spi_master_class); |
1718 | if (status < 0) | |
1719 | goto err2; | |
8ae12a0d | 1720 | return 0; |
b885244e DB |
1721 | |
1722 | err2: | |
1723 | bus_unregister(&spi_bus_type); | |
1724 | err1: | |
1725 | kfree(buf); | |
1726 | buf = NULL; | |
1727 | err0: | |
1728 | return status; | |
8ae12a0d | 1729 | } |
b885244e | 1730 | |
8ae12a0d DB |
1731 | /* board_info is normally registered in arch_initcall(), |
1732 | * but even essential drivers wait till later | |
b885244e DB |
1733 | * |
1734 | * REVISIT only boardinfo really needs static linking. the rest (device and | |
1735 | * driver registration) _could_ be dynamically linked (modular) ... costs | |
1736 | * include needing to have boardinfo data structures be much more public. | |
8ae12a0d | 1737 | */ |
673c0c00 | 1738 | postcore_initcall(spi_init); |
8ae12a0d | 1739 |