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> | |
99adef31 MB |
27 | #include <linux/dma-mapping.h> |
28 | #include <linux/dmaengine.h> | |
94040828 | 29 | #include <linux/mutex.h> |
2b7a32f7 | 30 | #include <linux/of_device.h> |
d57a4282 | 31 | #include <linux/of_irq.h> |
5a0e3ad6 | 32 | #include <linux/slab.h> |
e0626e38 | 33 | #include <linux/mod_devicetable.h> |
8ae12a0d | 34 | #include <linux/spi/spi.h> |
74317984 | 35 | #include <linux/of_gpio.h> |
3ae22e8c | 36 | #include <linux/pm_runtime.h> |
025ed130 | 37 | #include <linux/export.h> |
8bd75c77 | 38 | #include <linux/sched/rt.h> |
ffbbdd21 LW |
39 | #include <linux/delay.h> |
40 | #include <linux/kthread.h> | |
64bee4d2 MW |
41 | #include <linux/ioport.h> |
42 | #include <linux/acpi.h> | |
8ae12a0d | 43 | |
56ec1978 MB |
44 | #define CREATE_TRACE_POINTS |
45 | #include <trace/events/spi.h> | |
46 | ||
8ae12a0d DB |
47 | static void spidev_release(struct device *dev) |
48 | { | |
0ffa0285 | 49 | struct spi_device *spi = to_spi_device(dev); |
8ae12a0d DB |
50 | |
51 | /* spi masters may cleanup for released devices */ | |
52 | if (spi->master->cleanup) | |
53 | spi->master->cleanup(spi); | |
54 | ||
0c868461 | 55 | spi_master_put(spi->master); |
07a389fe | 56 | kfree(spi); |
8ae12a0d DB |
57 | } |
58 | ||
59 | static ssize_t | |
60 | modalias_show(struct device *dev, struct device_attribute *a, char *buf) | |
61 | { | |
62 | const struct spi_device *spi = to_spi_device(dev); | |
8c4ff6d0 ZR |
63 | int len; |
64 | ||
65 | len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1); | |
66 | if (len != -ENODEV) | |
67 | return len; | |
8ae12a0d | 68 | |
d8e328b3 | 69 | return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias); |
8ae12a0d | 70 | } |
aa7da564 | 71 | static DEVICE_ATTR_RO(modalias); |
8ae12a0d | 72 | |
aa7da564 GKH |
73 | static struct attribute *spi_dev_attrs[] = { |
74 | &dev_attr_modalias.attr, | |
75 | NULL, | |
8ae12a0d | 76 | }; |
aa7da564 | 77 | ATTRIBUTE_GROUPS(spi_dev); |
8ae12a0d DB |
78 | |
79 | /* modalias support makes "modprobe $MODALIAS" new-style hotplug work, | |
80 | * and the sysfs version makes coldplug work too. | |
81 | */ | |
82 | ||
75368bf6 AV |
83 | static const struct spi_device_id *spi_match_id(const struct spi_device_id *id, |
84 | const struct spi_device *sdev) | |
85 | { | |
86 | while (id->name[0]) { | |
87 | if (!strcmp(sdev->modalias, id->name)) | |
88 | return id; | |
89 | id++; | |
90 | } | |
91 | return NULL; | |
92 | } | |
93 | ||
94 | const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev) | |
95 | { | |
96 | const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver); | |
97 | ||
98 | return spi_match_id(sdrv->id_table, sdev); | |
99 | } | |
100 | EXPORT_SYMBOL_GPL(spi_get_device_id); | |
101 | ||
8ae12a0d DB |
102 | static int spi_match_device(struct device *dev, struct device_driver *drv) |
103 | { | |
104 | const struct spi_device *spi = to_spi_device(dev); | |
75368bf6 AV |
105 | const struct spi_driver *sdrv = to_spi_driver(drv); |
106 | ||
2b7a32f7 SA |
107 | /* Attempt an OF style match */ |
108 | if (of_driver_match_device(dev, drv)) | |
109 | return 1; | |
110 | ||
64bee4d2 MW |
111 | /* Then try ACPI */ |
112 | if (acpi_driver_match_device(dev, drv)) | |
113 | return 1; | |
114 | ||
75368bf6 AV |
115 | if (sdrv->id_table) |
116 | return !!spi_match_id(sdrv->id_table, spi); | |
8ae12a0d | 117 | |
35f74fca | 118 | return strcmp(spi->modalias, drv->name) == 0; |
8ae12a0d DB |
119 | } |
120 | ||
7eff2e7a | 121 | static int spi_uevent(struct device *dev, struct kobj_uevent_env *env) |
8ae12a0d DB |
122 | { |
123 | const struct spi_device *spi = to_spi_device(dev); | |
8c4ff6d0 ZR |
124 | int rc; |
125 | ||
126 | rc = acpi_device_uevent_modalias(dev, env); | |
127 | if (rc != -ENODEV) | |
128 | return rc; | |
8ae12a0d | 129 | |
e0626e38 | 130 | add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias); |
8ae12a0d DB |
131 | return 0; |
132 | } | |
133 | ||
3ae22e8c MB |
134 | #ifdef CONFIG_PM_SLEEP |
135 | static int spi_legacy_suspend(struct device *dev, pm_message_t message) | |
8ae12a0d | 136 | { |
3c72426f | 137 | int value = 0; |
b885244e | 138 | struct spi_driver *drv = to_spi_driver(dev->driver); |
8ae12a0d | 139 | |
8ae12a0d | 140 | /* suspend will stop irqs and dma; no more i/o */ |
3c72426f DB |
141 | if (drv) { |
142 | if (drv->suspend) | |
143 | value = drv->suspend(to_spi_device(dev), message); | |
144 | else | |
145 | dev_dbg(dev, "... can't suspend\n"); | |
146 | } | |
8ae12a0d DB |
147 | return value; |
148 | } | |
149 | ||
3ae22e8c | 150 | static int spi_legacy_resume(struct device *dev) |
8ae12a0d | 151 | { |
3c72426f | 152 | int value = 0; |
b885244e | 153 | struct spi_driver *drv = to_spi_driver(dev->driver); |
8ae12a0d | 154 | |
8ae12a0d | 155 | /* resume may restart the i/o queue */ |
3c72426f DB |
156 | if (drv) { |
157 | if (drv->resume) | |
158 | value = drv->resume(to_spi_device(dev)); | |
159 | else | |
160 | dev_dbg(dev, "... can't resume\n"); | |
161 | } | |
8ae12a0d DB |
162 | return value; |
163 | } | |
164 | ||
3ae22e8c MB |
165 | static int spi_pm_suspend(struct device *dev) |
166 | { | |
167 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
168 | ||
169 | if (pm) | |
170 | return pm_generic_suspend(dev); | |
171 | else | |
172 | return spi_legacy_suspend(dev, PMSG_SUSPEND); | |
173 | } | |
174 | ||
175 | static int spi_pm_resume(struct device *dev) | |
176 | { | |
177 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
178 | ||
179 | if (pm) | |
180 | return pm_generic_resume(dev); | |
181 | else | |
182 | return spi_legacy_resume(dev); | |
183 | } | |
184 | ||
185 | static int spi_pm_freeze(struct device *dev) | |
186 | { | |
187 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
188 | ||
189 | if (pm) | |
190 | return pm_generic_freeze(dev); | |
191 | else | |
192 | return spi_legacy_suspend(dev, PMSG_FREEZE); | |
193 | } | |
194 | ||
195 | static int spi_pm_thaw(struct device *dev) | |
196 | { | |
197 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
198 | ||
199 | if (pm) | |
200 | return pm_generic_thaw(dev); | |
201 | else | |
202 | return spi_legacy_resume(dev); | |
203 | } | |
204 | ||
205 | static int spi_pm_poweroff(struct device *dev) | |
206 | { | |
207 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
208 | ||
209 | if (pm) | |
210 | return pm_generic_poweroff(dev); | |
211 | else | |
212 | return spi_legacy_suspend(dev, PMSG_HIBERNATE); | |
213 | } | |
214 | ||
215 | static int spi_pm_restore(struct device *dev) | |
216 | { | |
217 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; | |
218 | ||
219 | if (pm) | |
220 | return pm_generic_restore(dev); | |
221 | else | |
222 | return spi_legacy_resume(dev); | |
223 | } | |
8ae12a0d | 224 | #else |
3ae22e8c MB |
225 | #define spi_pm_suspend NULL |
226 | #define spi_pm_resume NULL | |
227 | #define spi_pm_freeze NULL | |
228 | #define spi_pm_thaw NULL | |
229 | #define spi_pm_poweroff NULL | |
230 | #define spi_pm_restore NULL | |
8ae12a0d DB |
231 | #endif |
232 | ||
3ae22e8c MB |
233 | static const struct dev_pm_ops spi_pm = { |
234 | .suspend = spi_pm_suspend, | |
235 | .resume = spi_pm_resume, | |
236 | .freeze = spi_pm_freeze, | |
237 | .thaw = spi_pm_thaw, | |
238 | .poweroff = spi_pm_poweroff, | |
239 | .restore = spi_pm_restore, | |
240 | SET_RUNTIME_PM_OPS( | |
241 | pm_generic_runtime_suspend, | |
242 | pm_generic_runtime_resume, | |
45f0a85c | 243 | NULL |
3ae22e8c MB |
244 | ) |
245 | }; | |
246 | ||
8ae12a0d DB |
247 | struct bus_type spi_bus_type = { |
248 | .name = "spi", | |
aa7da564 | 249 | .dev_groups = spi_dev_groups, |
8ae12a0d DB |
250 | .match = spi_match_device, |
251 | .uevent = spi_uevent, | |
3ae22e8c | 252 | .pm = &spi_pm, |
8ae12a0d DB |
253 | }; |
254 | EXPORT_SYMBOL_GPL(spi_bus_type); | |
255 | ||
b885244e DB |
256 | |
257 | static int spi_drv_probe(struct device *dev) | |
258 | { | |
259 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); | |
33cf00e5 MW |
260 | struct spi_device *spi = to_spi_device(dev); |
261 | int ret; | |
262 | ||
263 | acpi_dev_pm_attach(&spi->dev, true); | |
264 | ret = sdrv->probe(spi); | |
265 | if (ret) | |
266 | acpi_dev_pm_detach(&spi->dev, true); | |
b885244e | 267 | |
33cf00e5 | 268 | return ret; |
b885244e DB |
269 | } |
270 | ||
271 | static int spi_drv_remove(struct device *dev) | |
272 | { | |
273 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); | |
33cf00e5 MW |
274 | struct spi_device *spi = to_spi_device(dev); |
275 | int ret; | |
276 | ||
277 | ret = sdrv->remove(spi); | |
278 | acpi_dev_pm_detach(&spi->dev, true); | |
b885244e | 279 | |
33cf00e5 | 280 | return ret; |
b885244e DB |
281 | } |
282 | ||
283 | static void spi_drv_shutdown(struct device *dev) | |
284 | { | |
285 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); | |
286 | ||
287 | sdrv->shutdown(to_spi_device(dev)); | |
288 | } | |
289 | ||
33e34dc6 DB |
290 | /** |
291 | * spi_register_driver - register a SPI driver | |
292 | * @sdrv: the driver to register | |
293 | * Context: can sleep | |
294 | */ | |
b885244e DB |
295 | int spi_register_driver(struct spi_driver *sdrv) |
296 | { | |
297 | sdrv->driver.bus = &spi_bus_type; | |
298 | if (sdrv->probe) | |
299 | sdrv->driver.probe = spi_drv_probe; | |
300 | if (sdrv->remove) | |
301 | sdrv->driver.remove = spi_drv_remove; | |
302 | if (sdrv->shutdown) | |
303 | sdrv->driver.shutdown = spi_drv_shutdown; | |
304 | return driver_register(&sdrv->driver); | |
305 | } | |
306 | EXPORT_SYMBOL_GPL(spi_register_driver); | |
307 | ||
8ae12a0d DB |
308 | /*-------------------------------------------------------------------------*/ |
309 | ||
310 | /* SPI devices should normally not be created by SPI device drivers; that | |
311 | * would make them board-specific. Similarly with SPI master drivers. | |
312 | * Device registration normally goes into like arch/.../mach.../board-YYY.c | |
313 | * with other readonly (flashable) information about mainboard devices. | |
314 | */ | |
315 | ||
316 | struct boardinfo { | |
317 | struct list_head list; | |
2b9603a0 | 318 | struct spi_board_info board_info; |
8ae12a0d DB |
319 | }; |
320 | ||
321 | static LIST_HEAD(board_list); | |
2b9603a0 FT |
322 | static LIST_HEAD(spi_master_list); |
323 | ||
324 | /* | |
325 | * Used to protect add/del opertion for board_info list and | |
326 | * spi_master list, and their matching process | |
327 | */ | |
94040828 | 328 | static DEFINE_MUTEX(board_lock); |
8ae12a0d | 329 | |
dc87c98e GL |
330 | /** |
331 | * spi_alloc_device - Allocate a new SPI device | |
332 | * @master: Controller to which device is connected | |
333 | * Context: can sleep | |
334 | * | |
335 | * Allows a driver to allocate and initialize a spi_device without | |
336 | * registering it immediately. This allows a driver to directly | |
337 | * fill the spi_device with device parameters before calling | |
338 | * spi_add_device() on it. | |
339 | * | |
340 | * Caller is responsible to call spi_add_device() on the returned | |
341 | * spi_device structure to add it to the SPI master. If the caller | |
342 | * needs to discard the spi_device without adding it, then it should | |
343 | * call spi_dev_put() on it. | |
344 | * | |
345 | * Returns a pointer to the new device, or NULL. | |
346 | */ | |
347 | struct spi_device *spi_alloc_device(struct spi_master *master) | |
348 | { | |
349 | struct spi_device *spi; | |
350 | struct device *dev = master->dev.parent; | |
351 | ||
352 | if (!spi_master_get(master)) | |
353 | return NULL; | |
354 | ||
5fe5f05e | 355 | spi = kzalloc(sizeof(*spi), GFP_KERNEL); |
dc87c98e GL |
356 | if (!spi) { |
357 | dev_err(dev, "cannot alloc spi_device\n"); | |
358 | spi_master_put(master); | |
359 | return NULL; | |
360 | } | |
361 | ||
362 | spi->master = master; | |
178db7d3 | 363 | spi->dev.parent = &master->dev; |
dc87c98e GL |
364 | spi->dev.bus = &spi_bus_type; |
365 | spi->dev.release = spidev_release; | |
446411e1 | 366 | spi->cs_gpio = -ENOENT; |
dc87c98e GL |
367 | device_initialize(&spi->dev); |
368 | return spi; | |
369 | } | |
370 | EXPORT_SYMBOL_GPL(spi_alloc_device); | |
371 | ||
e13ac47b JN |
372 | static void spi_dev_set_name(struct spi_device *spi) |
373 | { | |
374 | struct acpi_device *adev = ACPI_COMPANION(&spi->dev); | |
375 | ||
376 | if (adev) { | |
377 | dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev)); | |
378 | return; | |
379 | } | |
380 | ||
381 | dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev), | |
382 | spi->chip_select); | |
383 | } | |
384 | ||
b6fb8d3a MW |
385 | static int spi_dev_check(struct device *dev, void *data) |
386 | { | |
387 | struct spi_device *spi = to_spi_device(dev); | |
388 | struct spi_device *new_spi = data; | |
389 | ||
390 | if (spi->master == new_spi->master && | |
391 | spi->chip_select == new_spi->chip_select) | |
392 | return -EBUSY; | |
393 | return 0; | |
394 | } | |
395 | ||
dc87c98e GL |
396 | /** |
397 | * spi_add_device - Add spi_device allocated with spi_alloc_device | |
398 | * @spi: spi_device to register | |
399 | * | |
400 | * Companion function to spi_alloc_device. Devices allocated with | |
401 | * spi_alloc_device can be added onto the spi bus with this function. | |
402 | * | |
e48880e0 | 403 | * Returns 0 on success; negative errno on failure |
dc87c98e GL |
404 | */ |
405 | int spi_add_device(struct spi_device *spi) | |
406 | { | |
e48880e0 | 407 | static DEFINE_MUTEX(spi_add_lock); |
74317984 JCPV |
408 | struct spi_master *master = spi->master; |
409 | struct device *dev = master->dev.parent; | |
dc87c98e GL |
410 | int status; |
411 | ||
412 | /* Chipselects are numbered 0..max; validate. */ | |
74317984 | 413 | if (spi->chip_select >= master->num_chipselect) { |
dc87c98e GL |
414 | dev_err(dev, "cs%d >= max %d\n", |
415 | spi->chip_select, | |
74317984 | 416 | master->num_chipselect); |
dc87c98e GL |
417 | return -EINVAL; |
418 | } | |
419 | ||
420 | /* Set the bus ID string */ | |
e13ac47b | 421 | spi_dev_set_name(spi); |
e48880e0 DB |
422 | |
423 | /* We need to make sure there's no other device with this | |
424 | * chipselect **BEFORE** we call setup(), else we'll trash | |
425 | * its configuration. Lock against concurrent add() calls. | |
426 | */ | |
427 | mutex_lock(&spi_add_lock); | |
428 | ||
b6fb8d3a MW |
429 | status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check); |
430 | if (status) { | |
e48880e0 DB |
431 | dev_err(dev, "chipselect %d already in use\n", |
432 | spi->chip_select); | |
e48880e0 DB |
433 | goto done; |
434 | } | |
435 | ||
74317984 JCPV |
436 | if (master->cs_gpios) |
437 | spi->cs_gpio = master->cs_gpios[spi->chip_select]; | |
438 | ||
e48880e0 DB |
439 | /* Drivers may modify this initial i/o setup, but will |
440 | * normally rely on the device being setup. Devices | |
441 | * using SPI_CS_HIGH can't coexist well otherwise... | |
442 | */ | |
7d077197 | 443 | status = spi_setup(spi); |
dc87c98e | 444 | if (status < 0) { |
eb288a1f LW |
445 | dev_err(dev, "can't setup %s, status %d\n", |
446 | dev_name(&spi->dev), status); | |
e48880e0 | 447 | goto done; |
dc87c98e GL |
448 | } |
449 | ||
e48880e0 | 450 | /* Device may be bound to an active driver when this returns */ |
dc87c98e | 451 | status = device_add(&spi->dev); |
e48880e0 | 452 | if (status < 0) |
eb288a1f LW |
453 | dev_err(dev, "can't add %s, status %d\n", |
454 | dev_name(&spi->dev), status); | |
e48880e0 | 455 | else |
35f74fca | 456 | dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev)); |
dc87c98e | 457 | |
e48880e0 DB |
458 | done: |
459 | mutex_unlock(&spi_add_lock); | |
460 | return status; | |
dc87c98e GL |
461 | } |
462 | EXPORT_SYMBOL_GPL(spi_add_device); | |
8ae12a0d | 463 | |
33e34dc6 DB |
464 | /** |
465 | * spi_new_device - instantiate one new SPI device | |
466 | * @master: Controller to which device is connected | |
467 | * @chip: Describes the SPI device | |
468 | * Context: can sleep | |
469 | * | |
470 | * On typical mainboards, this is purely internal; and it's not needed | |
8ae12a0d DB |
471 | * after board init creates the hard-wired devices. Some development |
472 | * platforms may not be able to use spi_register_board_info though, and | |
473 | * this is exported so that for example a USB or parport based adapter | |
474 | * driver could add devices (which it would learn about out-of-band). | |
082c8cb4 DB |
475 | * |
476 | * Returns the new device, or NULL. | |
8ae12a0d | 477 | */ |
e9d5a461 AB |
478 | struct spi_device *spi_new_device(struct spi_master *master, |
479 | struct spi_board_info *chip) | |
8ae12a0d DB |
480 | { |
481 | struct spi_device *proxy; | |
8ae12a0d DB |
482 | int status; |
483 | ||
082c8cb4 DB |
484 | /* NOTE: caller did any chip->bus_num checks necessary. |
485 | * | |
486 | * Also, unless we change the return value convention to use | |
487 | * error-or-pointer (not NULL-or-pointer), troubleshootability | |
488 | * suggests syslogged diagnostics are best here (ugh). | |
489 | */ | |
490 | ||
dc87c98e GL |
491 | proxy = spi_alloc_device(master); |
492 | if (!proxy) | |
8ae12a0d DB |
493 | return NULL; |
494 | ||
102eb975 GL |
495 | WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias)); |
496 | ||
8ae12a0d DB |
497 | proxy->chip_select = chip->chip_select; |
498 | proxy->max_speed_hz = chip->max_speed_hz; | |
980a01c9 | 499 | proxy->mode = chip->mode; |
8ae12a0d | 500 | proxy->irq = chip->irq; |
102eb975 | 501 | strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias)); |
8ae12a0d DB |
502 | proxy->dev.platform_data = (void *) chip->platform_data; |
503 | proxy->controller_data = chip->controller_data; | |
504 | proxy->controller_state = NULL; | |
8ae12a0d | 505 | |
dc87c98e | 506 | status = spi_add_device(proxy); |
8ae12a0d | 507 | if (status < 0) { |
dc87c98e GL |
508 | spi_dev_put(proxy); |
509 | return NULL; | |
8ae12a0d DB |
510 | } |
511 | ||
8ae12a0d DB |
512 | return proxy; |
513 | } | |
514 | EXPORT_SYMBOL_GPL(spi_new_device); | |
515 | ||
2b9603a0 FT |
516 | static void spi_match_master_to_boardinfo(struct spi_master *master, |
517 | struct spi_board_info *bi) | |
518 | { | |
519 | struct spi_device *dev; | |
520 | ||
521 | if (master->bus_num != bi->bus_num) | |
522 | return; | |
523 | ||
524 | dev = spi_new_device(master, bi); | |
525 | if (!dev) | |
526 | dev_err(master->dev.parent, "can't create new device for %s\n", | |
527 | bi->modalias); | |
528 | } | |
529 | ||
33e34dc6 DB |
530 | /** |
531 | * spi_register_board_info - register SPI devices for a given board | |
532 | * @info: array of chip descriptors | |
533 | * @n: how many descriptors are provided | |
534 | * Context: can sleep | |
535 | * | |
8ae12a0d DB |
536 | * Board-specific early init code calls this (probably during arch_initcall) |
537 | * with segments of the SPI device table. Any device nodes are created later, | |
538 | * after the relevant parent SPI controller (bus_num) is defined. We keep | |
539 | * this table of devices forever, so that reloading a controller driver will | |
540 | * not make Linux forget about these hard-wired devices. | |
541 | * | |
542 | * Other code can also call this, e.g. a particular add-on board might provide | |
543 | * SPI devices through its expansion connector, so code initializing that board | |
544 | * would naturally declare its SPI devices. | |
545 | * | |
546 | * The board info passed can safely be __initdata ... but be careful of | |
547 | * any embedded pointers (platform_data, etc), they're copied as-is. | |
548 | */ | |
fd4a319b | 549 | int spi_register_board_info(struct spi_board_info const *info, unsigned n) |
8ae12a0d | 550 | { |
2b9603a0 FT |
551 | struct boardinfo *bi; |
552 | int i; | |
8ae12a0d | 553 | |
2b9603a0 | 554 | bi = kzalloc(n * sizeof(*bi), GFP_KERNEL); |
8ae12a0d DB |
555 | if (!bi) |
556 | return -ENOMEM; | |
8ae12a0d | 557 | |
2b9603a0 FT |
558 | for (i = 0; i < n; i++, bi++, info++) { |
559 | struct spi_master *master; | |
8ae12a0d | 560 | |
2b9603a0 FT |
561 | memcpy(&bi->board_info, info, sizeof(*info)); |
562 | mutex_lock(&board_lock); | |
563 | list_add_tail(&bi->list, &board_list); | |
564 | list_for_each_entry(master, &spi_master_list, list) | |
565 | spi_match_master_to_boardinfo(master, &bi->board_info); | |
566 | mutex_unlock(&board_lock); | |
8ae12a0d | 567 | } |
2b9603a0 FT |
568 | |
569 | return 0; | |
8ae12a0d DB |
570 | } |
571 | ||
572 | /*-------------------------------------------------------------------------*/ | |
573 | ||
b158935f MB |
574 | static void spi_set_cs(struct spi_device *spi, bool enable) |
575 | { | |
576 | if (spi->mode & SPI_CS_HIGH) | |
577 | enable = !enable; | |
578 | ||
579 | if (spi->cs_gpio >= 0) | |
580 | gpio_set_value(spi->cs_gpio, !enable); | |
581 | else if (spi->master->set_cs) | |
582 | spi->master->set_cs(spi, !enable); | |
583 | } | |
584 | ||
99adef31 MB |
585 | static int spi_map_msg(struct spi_master *master, struct spi_message *msg) |
586 | { | |
587 | struct device *dev = master->dev.parent; | |
588 | struct device *tx_dev, *rx_dev; | |
589 | struct spi_transfer *xfer; | |
590 | ||
591 | if (msg->is_dma_mapped || !master->can_dma) | |
592 | return 0; | |
593 | ||
594 | tx_dev = &master->dma_tx->dev->device; | |
595 | rx_dev = &master->dma_rx->dev->device; | |
596 | ||
597 | list_for_each_entry(xfer, &msg->transfers, transfer_list) { | |
598 | if (!master->can_dma(master, msg->spi, xfer)) | |
599 | continue; | |
600 | ||
601 | if (xfer->tx_buf != NULL) { | |
602 | xfer->tx_dma = dma_map_single(tx_dev, | |
603 | (void *)xfer->tx_buf, | |
604 | xfer->len, | |
605 | DMA_TO_DEVICE); | |
606 | if (dma_mapping_error(dev, xfer->tx_dma)) { | |
607 | dev_err(dev, "dma_map_single Tx failed\n"); | |
608 | return -ENOMEM; | |
609 | } | |
610 | } | |
611 | ||
612 | if (xfer->rx_buf != NULL) { | |
613 | xfer->rx_dma = dma_map_single(rx_dev, | |
614 | xfer->rx_buf, xfer->len, | |
615 | DMA_FROM_DEVICE); | |
616 | if (dma_mapping_error(dev, xfer->rx_dma)) { | |
617 | dev_err(dev, "dma_map_single Rx failed\n"); | |
618 | dma_unmap_single(tx_dev, xfer->tx_dma, | |
619 | xfer->len, DMA_TO_DEVICE); | |
620 | return -ENOMEM; | |
621 | } | |
622 | } | |
623 | } | |
624 | ||
625 | master->cur_msg_mapped = true; | |
626 | ||
627 | return 0; | |
628 | } | |
629 | ||
630 | static int spi_unmap_msg(struct spi_master *master, struct spi_message *msg) | |
631 | { | |
632 | struct spi_transfer *xfer; | |
633 | struct device *tx_dev, *rx_dev; | |
634 | ||
635 | if (!master->cur_msg_mapped || msg->is_dma_mapped || !master->can_dma) | |
636 | return 0; | |
637 | ||
638 | tx_dev = &master->dma_tx->dev->device; | |
639 | rx_dev = &master->dma_rx->dev->device; | |
640 | ||
641 | list_for_each_entry(xfer, &msg->transfers, transfer_list) { | |
642 | if (!master->can_dma(master, msg->spi, xfer)) | |
643 | continue; | |
644 | ||
645 | if (xfer->rx_buf) | |
646 | dma_unmap_single(rx_dev, xfer->rx_dma, xfer->len, | |
647 | DMA_FROM_DEVICE); | |
648 | if (xfer->tx_buf) | |
649 | dma_unmap_single(tx_dev, xfer->tx_dma, xfer->len, | |
650 | DMA_TO_DEVICE); | |
651 | } | |
652 | ||
653 | return 0; | |
654 | } | |
655 | ||
b158935f MB |
656 | /* |
657 | * spi_transfer_one_message - Default implementation of transfer_one_message() | |
658 | * | |
659 | * This is a standard implementation of transfer_one_message() for | |
660 | * drivers which impelment a transfer_one() operation. It provides | |
661 | * standard handling of delays and chip select management. | |
662 | */ | |
663 | static int spi_transfer_one_message(struct spi_master *master, | |
664 | struct spi_message *msg) | |
665 | { | |
666 | struct spi_transfer *xfer; | |
667 | bool cur_cs = true; | |
668 | bool keep_cs = false; | |
669 | int ret = 0; | |
670 | ||
671 | spi_set_cs(msg->spi, true); | |
672 | ||
673 | list_for_each_entry(xfer, &msg->transfers, transfer_list) { | |
674 | trace_spi_transfer_start(msg, xfer); | |
675 | ||
16735d02 | 676 | reinit_completion(&master->xfer_completion); |
b158935f MB |
677 | |
678 | ret = master->transfer_one(master, msg->spi, xfer); | |
679 | if (ret < 0) { | |
680 | dev_err(&msg->spi->dev, | |
681 | "SPI transfer failed: %d\n", ret); | |
682 | goto out; | |
683 | } | |
684 | ||
13a42798 AL |
685 | if (ret > 0) { |
686 | ret = 0; | |
b158935f | 687 | wait_for_completion(&master->xfer_completion); |
13a42798 | 688 | } |
b158935f MB |
689 | |
690 | trace_spi_transfer_stop(msg, xfer); | |
691 | ||
692 | if (msg->status != -EINPROGRESS) | |
693 | goto out; | |
694 | ||
695 | if (xfer->delay_usecs) | |
696 | udelay(xfer->delay_usecs); | |
697 | ||
698 | if (xfer->cs_change) { | |
699 | if (list_is_last(&xfer->transfer_list, | |
700 | &msg->transfers)) { | |
701 | keep_cs = true; | |
702 | } else { | |
703 | cur_cs = !cur_cs; | |
704 | spi_set_cs(msg->spi, cur_cs); | |
705 | } | |
706 | } | |
707 | ||
708 | msg->actual_length += xfer->len; | |
709 | } | |
710 | ||
711 | out: | |
712 | if (ret != 0 || !keep_cs) | |
713 | spi_set_cs(msg->spi, false); | |
714 | ||
715 | if (msg->status == -EINPROGRESS) | |
716 | msg->status = ret; | |
717 | ||
718 | spi_finalize_current_message(master); | |
719 | ||
720 | return ret; | |
721 | } | |
722 | ||
723 | /** | |
724 | * spi_finalize_current_transfer - report completion of a transfer | |
725 | * | |
726 | * Called by SPI drivers using the core transfer_one_message() | |
727 | * implementation to notify it that the current interrupt driven | |
9e8f4882 | 728 | * transfer has finished and the next one may be scheduled. |
b158935f MB |
729 | */ |
730 | void spi_finalize_current_transfer(struct spi_master *master) | |
731 | { | |
732 | complete(&master->xfer_completion); | |
733 | } | |
734 | EXPORT_SYMBOL_GPL(spi_finalize_current_transfer); | |
735 | ||
ffbbdd21 LW |
736 | /** |
737 | * spi_pump_messages - kthread work function which processes spi message queue | |
738 | * @work: pointer to kthread work struct contained in the master struct | |
739 | * | |
740 | * This function checks if there is any spi message in the queue that | |
741 | * needs processing and if so call out to the driver to initialize hardware | |
742 | * and transfer each message. | |
743 | * | |
744 | */ | |
745 | static void spi_pump_messages(struct kthread_work *work) | |
746 | { | |
747 | struct spi_master *master = | |
748 | container_of(work, struct spi_master, pump_messages); | |
749 | unsigned long flags; | |
750 | bool was_busy = false; | |
751 | int ret; | |
752 | ||
753 | /* Lock queue and check for queue work */ | |
754 | spin_lock_irqsave(&master->queue_lock, flags); | |
755 | if (list_empty(&master->queue) || !master->running) { | |
b0b36b86 BF |
756 | if (!master->busy) { |
757 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
758 | return; | |
ffbbdd21 LW |
759 | } |
760 | master->busy = false; | |
761 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
b0b36b86 BF |
762 | if (master->unprepare_transfer_hardware && |
763 | master->unprepare_transfer_hardware(master)) | |
764 | dev_err(&master->dev, | |
765 | "failed to unprepare transfer hardware\n"); | |
49834de2 MB |
766 | if (master->auto_runtime_pm) { |
767 | pm_runtime_mark_last_busy(master->dev.parent); | |
768 | pm_runtime_put_autosuspend(master->dev.parent); | |
769 | } | |
56ec1978 | 770 | trace_spi_master_idle(master); |
ffbbdd21 LW |
771 | return; |
772 | } | |
773 | ||
774 | /* Make sure we are not already running a message */ | |
775 | if (master->cur_msg) { | |
776 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
777 | return; | |
778 | } | |
779 | /* Extract head of queue */ | |
780 | master->cur_msg = | |
a89e2d27 | 781 | list_first_entry(&master->queue, struct spi_message, queue); |
ffbbdd21 LW |
782 | |
783 | list_del_init(&master->cur_msg->queue); | |
784 | if (master->busy) | |
785 | was_busy = true; | |
786 | else | |
787 | master->busy = true; | |
788 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
789 | ||
49834de2 MB |
790 | if (!was_busy && master->auto_runtime_pm) { |
791 | ret = pm_runtime_get_sync(master->dev.parent); | |
792 | if (ret < 0) { | |
793 | dev_err(&master->dev, "Failed to power device: %d\n", | |
794 | ret); | |
795 | return; | |
796 | } | |
797 | } | |
798 | ||
56ec1978 MB |
799 | if (!was_busy) |
800 | trace_spi_master_busy(master); | |
801 | ||
7dfd2bd7 | 802 | if (!was_busy && master->prepare_transfer_hardware) { |
ffbbdd21 LW |
803 | ret = master->prepare_transfer_hardware(master); |
804 | if (ret) { | |
805 | dev_err(&master->dev, | |
806 | "failed to prepare transfer hardware\n"); | |
49834de2 MB |
807 | |
808 | if (master->auto_runtime_pm) | |
809 | pm_runtime_put(master->dev.parent); | |
ffbbdd21 LW |
810 | return; |
811 | } | |
812 | } | |
813 | ||
56ec1978 MB |
814 | trace_spi_message_start(master->cur_msg); |
815 | ||
2841a5fc MB |
816 | if (master->prepare_message) { |
817 | ret = master->prepare_message(master, master->cur_msg); | |
818 | if (ret) { | |
819 | dev_err(&master->dev, | |
820 | "failed to prepare message: %d\n", ret); | |
821 | master->cur_msg->status = ret; | |
822 | spi_finalize_current_message(master); | |
823 | return; | |
824 | } | |
825 | master->cur_msg_prepared = true; | |
826 | } | |
827 | ||
99adef31 MB |
828 | ret = spi_map_msg(master, master->cur_msg); |
829 | if (ret) { | |
830 | master->cur_msg->status = ret; | |
831 | spi_finalize_current_message(master); | |
832 | return; | |
833 | } | |
834 | ||
ffbbdd21 LW |
835 | ret = master->transfer_one_message(master, master->cur_msg); |
836 | if (ret) { | |
837 | dev_err(&master->dev, | |
e120cc0d DS |
838 | "failed to transfer one message from queue: %d\n", ret); |
839 | master->cur_msg->status = ret; | |
840 | spi_finalize_current_message(master); | |
ffbbdd21 LW |
841 | return; |
842 | } | |
843 | } | |
844 | ||
845 | static int spi_init_queue(struct spi_master *master) | |
846 | { | |
847 | struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 }; | |
848 | ||
849 | INIT_LIST_HEAD(&master->queue); | |
850 | spin_lock_init(&master->queue_lock); | |
851 | ||
852 | master->running = false; | |
853 | master->busy = false; | |
854 | ||
855 | init_kthread_worker(&master->kworker); | |
856 | master->kworker_task = kthread_run(kthread_worker_fn, | |
f170168b | 857 | &master->kworker, "%s", |
ffbbdd21 LW |
858 | dev_name(&master->dev)); |
859 | if (IS_ERR(master->kworker_task)) { | |
860 | dev_err(&master->dev, "failed to create message pump task\n"); | |
861 | return -ENOMEM; | |
862 | } | |
863 | init_kthread_work(&master->pump_messages, spi_pump_messages); | |
864 | ||
865 | /* | |
866 | * Master config will indicate if this controller should run the | |
867 | * message pump with high (realtime) priority to reduce the transfer | |
868 | * latency on the bus by minimising the delay between a transfer | |
869 | * request and the scheduling of the message pump thread. Without this | |
870 | * setting the message pump thread will remain at default priority. | |
871 | */ | |
872 | if (master->rt) { | |
873 | dev_info(&master->dev, | |
874 | "will run message pump with realtime priority\n"); | |
875 | sched_setscheduler(master->kworker_task, SCHED_FIFO, ¶m); | |
876 | } | |
877 | ||
878 | return 0; | |
879 | } | |
880 | ||
881 | /** | |
882 | * spi_get_next_queued_message() - called by driver to check for queued | |
883 | * messages | |
884 | * @master: the master to check for queued messages | |
885 | * | |
886 | * If there are more messages in the queue, the next message is returned from | |
887 | * this call. | |
888 | */ | |
889 | struct spi_message *spi_get_next_queued_message(struct spi_master *master) | |
890 | { | |
891 | struct spi_message *next; | |
892 | unsigned long flags; | |
893 | ||
894 | /* get a pointer to the next message, if any */ | |
895 | spin_lock_irqsave(&master->queue_lock, flags); | |
1cfd97f9 AL |
896 | next = list_first_entry_or_null(&master->queue, struct spi_message, |
897 | queue); | |
ffbbdd21 LW |
898 | spin_unlock_irqrestore(&master->queue_lock, flags); |
899 | ||
900 | return next; | |
901 | } | |
902 | EXPORT_SYMBOL_GPL(spi_get_next_queued_message); | |
903 | ||
904 | /** | |
905 | * spi_finalize_current_message() - the current message is complete | |
906 | * @master: the master to return the message to | |
907 | * | |
908 | * Called by the driver to notify the core that the message in the front of the | |
909 | * queue is complete and can be removed from the queue. | |
910 | */ | |
911 | void spi_finalize_current_message(struct spi_master *master) | |
912 | { | |
913 | struct spi_message *mesg; | |
914 | unsigned long flags; | |
2841a5fc | 915 | int ret; |
ffbbdd21 LW |
916 | |
917 | spin_lock_irqsave(&master->queue_lock, flags); | |
918 | mesg = master->cur_msg; | |
919 | master->cur_msg = NULL; | |
920 | ||
921 | queue_kthread_work(&master->kworker, &master->pump_messages); | |
922 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
923 | ||
99adef31 MB |
924 | spi_unmap_msg(master, mesg); |
925 | ||
2841a5fc MB |
926 | if (master->cur_msg_prepared && master->unprepare_message) { |
927 | ret = master->unprepare_message(master, mesg); | |
928 | if (ret) { | |
929 | dev_err(&master->dev, | |
930 | "failed to unprepare message: %d\n", ret); | |
931 | } | |
932 | } | |
933 | master->cur_msg_prepared = false; | |
934 | ||
ffbbdd21 LW |
935 | mesg->state = NULL; |
936 | if (mesg->complete) | |
937 | mesg->complete(mesg->context); | |
56ec1978 MB |
938 | |
939 | trace_spi_message_done(mesg); | |
ffbbdd21 LW |
940 | } |
941 | EXPORT_SYMBOL_GPL(spi_finalize_current_message); | |
942 | ||
943 | static int spi_start_queue(struct spi_master *master) | |
944 | { | |
945 | unsigned long flags; | |
946 | ||
947 | spin_lock_irqsave(&master->queue_lock, flags); | |
948 | ||
949 | if (master->running || master->busy) { | |
950 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
951 | return -EBUSY; | |
952 | } | |
953 | ||
954 | master->running = true; | |
955 | master->cur_msg = NULL; | |
956 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
957 | ||
958 | queue_kthread_work(&master->kworker, &master->pump_messages); | |
959 | ||
960 | return 0; | |
961 | } | |
962 | ||
963 | static int spi_stop_queue(struct spi_master *master) | |
964 | { | |
965 | unsigned long flags; | |
966 | unsigned limit = 500; | |
967 | int ret = 0; | |
968 | ||
969 | spin_lock_irqsave(&master->queue_lock, flags); | |
970 | ||
971 | /* | |
972 | * This is a bit lame, but is optimized for the common execution path. | |
973 | * A wait_queue on the master->busy could be used, but then the common | |
974 | * execution path (pump_messages) would be required to call wake_up or | |
975 | * friends on every SPI message. Do this instead. | |
976 | */ | |
977 | while ((!list_empty(&master->queue) || master->busy) && limit--) { | |
978 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
979 | msleep(10); | |
980 | spin_lock_irqsave(&master->queue_lock, flags); | |
981 | } | |
982 | ||
983 | if (!list_empty(&master->queue) || master->busy) | |
984 | ret = -EBUSY; | |
985 | else | |
986 | master->running = false; | |
987 | ||
988 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
989 | ||
990 | if (ret) { | |
991 | dev_warn(&master->dev, | |
992 | "could not stop message queue\n"); | |
993 | return ret; | |
994 | } | |
995 | return ret; | |
996 | } | |
997 | ||
998 | static int spi_destroy_queue(struct spi_master *master) | |
999 | { | |
1000 | int ret; | |
1001 | ||
1002 | ret = spi_stop_queue(master); | |
1003 | ||
1004 | /* | |
1005 | * flush_kthread_worker will block until all work is done. | |
1006 | * If the reason that stop_queue timed out is that the work will never | |
1007 | * finish, then it does no good to call flush/stop thread, so | |
1008 | * return anyway. | |
1009 | */ | |
1010 | if (ret) { | |
1011 | dev_err(&master->dev, "problem destroying queue\n"); | |
1012 | return ret; | |
1013 | } | |
1014 | ||
1015 | flush_kthread_worker(&master->kworker); | |
1016 | kthread_stop(master->kworker_task); | |
1017 | ||
1018 | return 0; | |
1019 | } | |
1020 | ||
1021 | /** | |
1022 | * spi_queued_transfer - transfer function for queued transfers | |
1023 | * @spi: spi device which is requesting transfer | |
1024 | * @msg: spi message which is to handled is queued to driver queue | |
1025 | */ | |
1026 | static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg) | |
1027 | { | |
1028 | struct spi_master *master = spi->master; | |
1029 | unsigned long flags; | |
1030 | ||
1031 | spin_lock_irqsave(&master->queue_lock, flags); | |
1032 | ||
1033 | if (!master->running) { | |
1034 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
1035 | return -ESHUTDOWN; | |
1036 | } | |
1037 | msg->actual_length = 0; | |
1038 | msg->status = -EINPROGRESS; | |
1039 | ||
1040 | list_add_tail(&msg->queue, &master->queue); | |
96b3eace | 1041 | if (!master->busy) |
ffbbdd21 LW |
1042 | queue_kthread_work(&master->kworker, &master->pump_messages); |
1043 | ||
1044 | spin_unlock_irqrestore(&master->queue_lock, flags); | |
1045 | return 0; | |
1046 | } | |
1047 | ||
1048 | static int spi_master_initialize_queue(struct spi_master *master) | |
1049 | { | |
1050 | int ret; | |
1051 | ||
1052 | master->queued = true; | |
1053 | master->transfer = spi_queued_transfer; | |
b158935f MB |
1054 | if (!master->transfer_one_message) |
1055 | master->transfer_one_message = spi_transfer_one_message; | |
ffbbdd21 LW |
1056 | |
1057 | /* Initialize and start queue */ | |
1058 | ret = spi_init_queue(master); | |
1059 | if (ret) { | |
1060 | dev_err(&master->dev, "problem initializing queue\n"); | |
1061 | goto err_init_queue; | |
1062 | } | |
1063 | ret = spi_start_queue(master); | |
1064 | if (ret) { | |
1065 | dev_err(&master->dev, "problem starting queue\n"); | |
1066 | goto err_start_queue; | |
1067 | } | |
1068 | ||
1069 | return 0; | |
1070 | ||
1071 | err_start_queue: | |
1072 | err_init_queue: | |
1073 | spi_destroy_queue(master); | |
1074 | return ret; | |
1075 | } | |
1076 | ||
1077 | /*-------------------------------------------------------------------------*/ | |
1078 | ||
7cb94361 | 1079 | #if defined(CONFIG_OF) |
d57a4282 GL |
1080 | /** |
1081 | * of_register_spi_devices() - Register child devices onto the SPI bus | |
1082 | * @master: Pointer to spi_master device | |
1083 | * | |
1084 | * Registers an spi_device for each child node of master node which has a 'reg' | |
1085 | * property. | |
1086 | */ | |
1087 | static void of_register_spi_devices(struct spi_master *master) | |
1088 | { | |
1089 | struct spi_device *spi; | |
1090 | struct device_node *nc; | |
d57a4282 | 1091 | int rc; |
89da4293 | 1092 | u32 value; |
d57a4282 GL |
1093 | |
1094 | if (!master->dev.of_node) | |
1095 | return; | |
1096 | ||
f3b6159e | 1097 | for_each_available_child_of_node(master->dev.of_node, nc) { |
d57a4282 GL |
1098 | /* Alloc an spi_device */ |
1099 | spi = spi_alloc_device(master); | |
1100 | if (!spi) { | |
1101 | dev_err(&master->dev, "spi_device alloc error for %s\n", | |
1102 | nc->full_name); | |
1103 | spi_dev_put(spi); | |
1104 | continue; | |
1105 | } | |
1106 | ||
1107 | /* Select device driver */ | |
1108 | if (of_modalias_node(nc, spi->modalias, | |
1109 | sizeof(spi->modalias)) < 0) { | |
1110 | dev_err(&master->dev, "cannot find modalias for %s\n", | |
1111 | nc->full_name); | |
1112 | spi_dev_put(spi); | |
1113 | continue; | |
1114 | } | |
1115 | ||
1116 | /* Device address */ | |
89da4293 TP |
1117 | rc = of_property_read_u32(nc, "reg", &value); |
1118 | if (rc) { | |
1119 | dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n", | |
1120 | nc->full_name, rc); | |
d57a4282 GL |
1121 | spi_dev_put(spi); |
1122 | continue; | |
1123 | } | |
89da4293 | 1124 | spi->chip_select = value; |
d57a4282 GL |
1125 | |
1126 | /* Mode (clock phase/polarity/etc.) */ | |
1127 | if (of_find_property(nc, "spi-cpha", NULL)) | |
1128 | spi->mode |= SPI_CPHA; | |
1129 | if (of_find_property(nc, "spi-cpol", NULL)) | |
1130 | spi->mode |= SPI_CPOL; | |
1131 | if (of_find_property(nc, "spi-cs-high", NULL)) | |
1132 | spi->mode |= SPI_CS_HIGH; | |
c20151df LPC |
1133 | if (of_find_property(nc, "spi-3wire", NULL)) |
1134 | spi->mode |= SPI_3WIRE; | |
d57a4282 | 1135 | |
f477b7fb | 1136 | /* Device DUAL/QUAD mode */ |
89da4293 TP |
1137 | if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) { |
1138 | switch (value) { | |
1139 | case 1: | |
a822e99c | 1140 | break; |
89da4293 | 1141 | case 2: |
a822e99c MB |
1142 | spi->mode |= SPI_TX_DUAL; |
1143 | break; | |
89da4293 | 1144 | case 4: |
a822e99c MB |
1145 | spi->mode |= SPI_TX_QUAD; |
1146 | break; | |
1147 | default: | |
1148 | dev_err(&master->dev, | |
a110f93d | 1149 | "spi-tx-bus-width %d not supported\n", |
89da4293 | 1150 | value); |
a822e99c MB |
1151 | spi_dev_put(spi); |
1152 | continue; | |
1153 | } | |
f477b7fb | 1154 | } |
1155 | ||
89da4293 TP |
1156 | if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) { |
1157 | switch (value) { | |
1158 | case 1: | |
a822e99c | 1159 | break; |
89da4293 | 1160 | case 2: |
a822e99c MB |
1161 | spi->mode |= SPI_RX_DUAL; |
1162 | break; | |
89da4293 | 1163 | case 4: |
a822e99c MB |
1164 | spi->mode |= SPI_RX_QUAD; |
1165 | break; | |
1166 | default: | |
1167 | dev_err(&master->dev, | |
a110f93d | 1168 | "spi-rx-bus-width %d not supported\n", |
89da4293 | 1169 | value); |
a822e99c MB |
1170 | spi_dev_put(spi); |
1171 | continue; | |
1172 | } | |
f477b7fb | 1173 | } |
1174 | ||
d57a4282 | 1175 | /* Device speed */ |
89da4293 TP |
1176 | rc = of_property_read_u32(nc, "spi-max-frequency", &value); |
1177 | if (rc) { | |
1178 | dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n", | |
1179 | nc->full_name, rc); | |
d57a4282 GL |
1180 | spi_dev_put(spi); |
1181 | continue; | |
1182 | } | |
89da4293 | 1183 | spi->max_speed_hz = value; |
d57a4282 GL |
1184 | |
1185 | /* IRQ */ | |
1186 | spi->irq = irq_of_parse_and_map(nc, 0); | |
1187 | ||
1188 | /* Store a pointer to the node in the device structure */ | |
1189 | of_node_get(nc); | |
1190 | spi->dev.of_node = nc; | |
1191 | ||
1192 | /* Register the new device */ | |
70fac17c | 1193 | request_module("%s%s", SPI_MODULE_PREFIX, spi->modalias); |
d57a4282 GL |
1194 | rc = spi_add_device(spi); |
1195 | if (rc) { | |
1196 | dev_err(&master->dev, "spi_device register error %s\n", | |
1197 | nc->full_name); | |
1198 | spi_dev_put(spi); | |
1199 | } | |
1200 | ||
1201 | } | |
1202 | } | |
1203 | #else | |
1204 | static void of_register_spi_devices(struct spi_master *master) { } | |
1205 | #endif | |
1206 | ||
64bee4d2 MW |
1207 | #ifdef CONFIG_ACPI |
1208 | static int acpi_spi_add_resource(struct acpi_resource *ares, void *data) | |
1209 | { | |
1210 | struct spi_device *spi = data; | |
1211 | ||
1212 | if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) { | |
1213 | struct acpi_resource_spi_serialbus *sb; | |
1214 | ||
1215 | sb = &ares->data.spi_serial_bus; | |
1216 | if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) { | |
1217 | spi->chip_select = sb->device_selection; | |
1218 | spi->max_speed_hz = sb->connection_speed; | |
1219 | ||
1220 | if (sb->clock_phase == ACPI_SPI_SECOND_PHASE) | |
1221 | spi->mode |= SPI_CPHA; | |
1222 | if (sb->clock_polarity == ACPI_SPI_START_HIGH) | |
1223 | spi->mode |= SPI_CPOL; | |
1224 | if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH) | |
1225 | spi->mode |= SPI_CS_HIGH; | |
1226 | } | |
1227 | } else if (spi->irq < 0) { | |
1228 | struct resource r; | |
1229 | ||
1230 | if (acpi_dev_resource_interrupt(ares, 0, &r)) | |
1231 | spi->irq = r.start; | |
1232 | } | |
1233 | ||
1234 | /* Always tell the ACPI core to skip this resource */ | |
1235 | return 1; | |
1236 | } | |
1237 | ||
1238 | static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level, | |
1239 | void *data, void **return_value) | |
1240 | { | |
1241 | struct spi_master *master = data; | |
1242 | struct list_head resource_list; | |
1243 | struct acpi_device *adev; | |
1244 | struct spi_device *spi; | |
1245 | int ret; | |
1246 | ||
1247 | if (acpi_bus_get_device(handle, &adev)) | |
1248 | return AE_OK; | |
1249 | if (acpi_bus_get_status(adev) || !adev->status.present) | |
1250 | return AE_OK; | |
1251 | ||
1252 | spi = spi_alloc_device(master); | |
1253 | if (!spi) { | |
1254 | dev_err(&master->dev, "failed to allocate SPI device for %s\n", | |
1255 | dev_name(&adev->dev)); | |
1256 | return AE_NO_MEMORY; | |
1257 | } | |
1258 | ||
7b199811 | 1259 | ACPI_COMPANION_SET(&spi->dev, adev); |
64bee4d2 MW |
1260 | spi->irq = -1; |
1261 | ||
1262 | INIT_LIST_HEAD(&resource_list); | |
1263 | ret = acpi_dev_get_resources(adev, &resource_list, | |
1264 | acpi_spi_add_resource, spi); | |
1265 | acpi_dev_free_resource_list(&resource_list); | |
1266 | ||
1267 | if (ret < 0 || !spi->max_speed_hz) { | |
1268 | spi_dev_put(spi); | |
1269 | return AE_OK; | |
1270 | } | |
1271 | ||
33cf00e5 | 1272 | adev->power.flags.ignore_parent = true; |
cf9eb39c | 1273 | strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias)); |
64bee4d2 | 1274 | if (spi_add_device(spi)) { |
33cf00e5 | 1275 | adev->power.flags.ignore_parent = false; |
64bee4d2 MW |
1276 | dev_err(&master->dev, "failed to add SPI device %s from ACPI\n", |
1277 | dev_name(&adev->dev)); | |
1278 | spi_dev_put(spi); | |
1279 | } | |
1280 | ||
1281 | return AE_OK; | |
1282 | } | |
1283 | ||
1284 | static void acpi_register_spi_devices(struct spi_master *master) | |
1285 | { | |
1286 | acpi_status status; | |
1287 | acpi_handle handle; | |
1288 | ||
29896178 | 1289 | handle = ACPI_HANDLE(master->dev.parent); |
64bee4d2 MW |
1290 | if (!handle) |
1291 | return; | |
1292 | ||
1293 | status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1, | |
1294 | acpi_spi_add_device, NULL, | |
1295 | master, NULL); | |
1296 | if (ACPI_FAILURE(status)) | |
1297 | dev_warn(&master->dev, "failed to enumerate SPI slaves\n"); | |
1298 | } | |
1299 | #else | |
1300 | static inline void acpi_register_spi_devices(struct spi_master *master) {} | |
1301 | #endif /* CONFIG_ACPI */ | |
1302 | ||
49dce689 | 1303 | static void spi_master_release(struct device *dev) |
8ae12a0d DB |
1304 | { |
1305 | struct spi_master *master; | |
1306 | ||
49dce689 | 1307 | master = container_of(dev, struct spi_master, dev); |
8ae12a0d DB |
1308 | kfree(master); |
1309 | } | |
1310 | ||
1311 | static struct class spi_master_class = { | |
1312 | .name = "spi_master", | |
1313 | .owner = THIS_MODULE, | |
49dce689 | 1314 | .dev_release = spi_master_release, |
8ae12a0d DB |
1315 | }; |
1316 | ||
1317 | ||
ffbbdd21 | 1318 | |
8ae12a0d DB |
1319 | /** |
1320 | * spi_alloc_master - allocate SPI master controller | |
1321 | * @dev: the controller, possibly using the platform_bus | |
33e34dc6 | 1322 | * @size: how much zeroed driver-private data to allocate; the pointer to this |
49dce689 | 1323 | * memory is in the driver_data field of the returned device, |
0c868461 | 1324 | * accessible with spi_master_get_devdata(). |
33e34dc6 | 1325 | * Context: can sleep |
8ae12a0d DB |
1326 | * |
1327 | * This call is used only by SPI master controller drivers, which are the | |
1328 | * only ones directly touching chip registers. It's how they allocate | |
ba1a0513 | 1329 | * an spi_master structure, prior to calling spi_register_master(). |
8ae12a0d DB |
1330 | * |
1331 | * This must be called from context that can sleep. It returns the SPI | |
1332 | * master structure on success, else NULL. | |
1333 | * | |
1334 | * The caller is responsible for assigning the bus number and initializing | |
ba1a0513 | 1335 | * the master's methods before calling spi_register_master(); and (after errors |
eb4af0f5 UKK |
1336 | * adding the device) calling spi_master_put() and kfree() to prevent a memory |
1337 | * leak. | |
8ae12a0d | 1338 | */ |
e9d5a461 | 1339 | struct spi_master *spi_alloc_master(struct device *dev, unsigned size) |
8ae12a0d DB |
1340 | { |
1341 | struct spi_master *master; | |
1342 | ||
0c868461 DB |
1343 | if (!dev) |
1344 | return NULL; | |
1345 | ||
5fe5f05e | 1346 | master = kzalloc(size + sizeof(*master), GFP_KERNEL); |
8ae12a0d DB |
1347 | if (!master) |
1348 | return NULL; | |
1349 | ||
49dce689 | 1350 | device_initialize(&master->dev); |
1e8a52e1 GL |
1351 | master->bus_num = -1; |
1352 | master->num_chipselect = 1; | |
49dce689 TJ |
1353 | master->dev.class = &spi_master_class; |
1354 | master->dev.parent = get_device(dev); | |
0c868461 | 1355 | spi_master_set_devdata(master, &master[1]); |
8ae12a0d DB |
1356 | |
1357 | return master; | |
1358 | } | |
1359 | EXPORT_SYMBOL_GPL(spi_alloc_master); | |
1360 | ||
74317984 JCPV |
1361 | #ifdef CONFIG_OF |
1362 | static int of_spi_register_master(struct spi_master *master) | |
1363 | { | |
e80beb27 | 1364 | int nb, i, *cs; |
74317984 JCPV |
1365 | struct device_node *np = master->dev.of_node; |
1366 | ||
1367 | if (!np) | |
1368 | return 0; | |
1369 | ||
1370 | nb = of_gpio_named_count(np, "cs-gpios"); | |
5fe5f05e | 1371 | master->num_chipselect = max_t(int, nb, master->num_chipselect); |
74317984 | 1372 | |
8ec5d84e AL |
1373 | /* Return error only for an incorrectly formed cs-gpios property */ |
1374 | if (nb == 0 || nb == -ENOENT) | |
74317984 | 1375 | return 0; |
8ec5d84e AL |
1376 | else if (nb < 0) |
1377 | return nb; | |
74317984 JCPV |
1378 | |
1379 | cs = devm_kzalloc(&master->dev, | |
1380 | sizeof(int) * master->num_chipselect, | |
1381 | GFP_KERNEL); | |
1382 | master->cs_gpios = cs; | |
1383 | ||
1384 | if (!master->cs_gpios) | |
1385 | return -ENOMEM; | |
1386 | ||
0da83bb1 | 1387 | for (i = 0; i < master->num_chipselect; i++) |
446411e1 | 1388 | cs[i] = -ENOENT; |
74317984 JCPV |
1389 | |
1390 | for (i = 0; i < nb; i++) | |
1391 | cs[i] = of_get_named_gpio(np, "cs-gpios", i); | |
1392 | ||
1393 | return 0; | |
1394 | } | |
1395 | #else | |
1396 | static int of_spi_register_master(struct spi_master *master) | |
1397 | { | |
1398 | return 0; | |
1399 | } | |
1400 | #endif | |
1401 | ||
8ae12a0d DB |
1402 | /** |
1403 | * spi_register_master - register SPI master controller | |
1404 | * @master: initialized master, originally from spi_alloc_master() | |
33e34dc6 | 1405 | * Context: can sleep |
8ae12a0d DB |
1406 | * |
1407 | * SPI master controllers connect to their drivers using some non-SPI bus, | |
1408 | * such as the platform bus. The final stage of probe() in that code | |
1409 | * includes calling spi_register_master() to hook up to this SPI bus glue. | |
1410 | * | |
1411 | * SPI controllers use board specific (often SOC specific) bus numbers, | |
1412 | * and board-specific addressing for SPI devices combines those numbers | |
1413 | * with chip select numbers. Since SPI does not directly support dynamic | |
1414 | * device identification, boards need configuration tables telling which | |
1415 | * chip is at which address. | |
1416 | * | |
1417 | * This must be called from context that can sleep. It returns zero on | |
1418 | * success, else a negative error code (dropping the master's refcount). | |
0c868461 DB |
1419 | * After a successful return, the caller is responsible for calling |
1420 | * spi_unregister_master(). | |
8ae12a0d | 1421 | */ |
e9d5a461 | 1422 | int spi_register_master(struct spi_master *master) |
8ae12a0d | 1423 | { |
e44a45ae | 1424 | static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1); |
49dce689 | 1425 | struct device *dev = master->dev.parent; |
2b9603a0 | 1426 | struct boardinfo *bi; |
8ae12a0d DB |
1427 | int status = -ENODEV; |
1428 | int dynamic = 0; | |
1429 | ||
0c868461 DB |
1430 | if (!dev) |
1431 | return -ENODEV; | |
1432 | ||
74317984 JCPV |
1433 | status = of_spi_register_master(master); |
1434 | if (status) | |
1435 | return status; | |
1436 | ||
082c8cb4 DB |
1437 | /* even if it's just one always-selected device, there must |
1438 | * be at least one chipselect | |
1439 | */ | |
1440 | if (master->num_chipselect == 0) | |
1441 | return -EINVAL; | |
1442 | ||
bb29785e GL |
1443 | if ((master->bus_num < 0) && master->dev.of_node) |
1444 | master->bus_num = of_alias_get_id(master->dev.of_node, "spi"); | |
1445 | ||
8ae12a0d | 1446 | /* convention: dynamically assigned bus IDs count down from the max */ |
a020ed75 | 1447 | if (master->bus_num < 0) { |
082c8cb4 DB |
1448 | /* FIXME switch to an IDR based scheme, something like |
1449 | * I2C now uses, so we can't run out of "dynamic" IDs | |
1450 | */ | |
8ae12a0d | 1451 | master->bus_num = atomic_dec_return(&dyn_bus_id); |
b885244e | 1452 | dynamic = 1; |
8ae12a0d DB |
1453 | } |
1454 | ||
cf32b71e ES |
1455 | spin_lock_init(&master->bus_lock_spinlock); |
1456 | mutex_init(&master->bus_lock_mutex); | |
1457 | master->bus_lock_flag = 0; | |
b158935f | 1458 | init_completion(&master->xfer_completion); |
cf32b71e | 1459 | |
8ae12a0d DB |
1460 | /* register the device, then userspace will see it. |
1461 | * registration fails if the bus ID is in use. | |
1462 | */ | |
35f74fca | 1463 | dev_set_name(&master->dev, "spi%u", master->bus_num); |
49dce689 | 1464 | status = device_add(&master->dev); |
b885244e | 1465 | if (status < 0) |
8ae12a0d | 1466 | goto done; |
35f74fca | 1467 | dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev), |
8ae12a0d DB |
1468 | dynamic ? " (dynamic)" : ""); |
1469 | ||
ffbbdd21 LW |
1470 | /* If we're using a queued driver, start the queue */ |
1471 | if (master->transfer) | |
1472 | dev_info(dev, "master is unqueued, this is deprecated\n"); | |
1473 | else { | |
1474 | status = spi_master_initialize_queue(master); | |
1475 | if (status) { | |
e93b0724 | 1476 | device_del(&master->dev); |
ffbbdd21 LW |
1477 | goto done; |
1478 | } | |
1479 | } | |
1480 | ||
2b9603a0 FT |
1481 | mutex_lock(&board_lock); |
1482 | list_add_tail(&master->list, &spi_master_list); | |
1483 | list_for_each_entry(bi, &board_list, list) | |
1484 | spi_match_master_to_boardinfo(master, &bi->board_info); | |
1485 | mutex_unlock(&board_lock); | |
1486 | ||
64bee4d2 | 1487 | /* Register devices from the device tree and ACPI */ |
12b15e83 | 1488 | of_register_spi_devices(master); |
64bee4d2 | 1489 | acpi_register_spi_devices(master); |
8ae12a0d DB |
1490 | done: |
1491 | return status; | |
1492 | } | |
1493 | EXPORT_SYMBOL_GPL(spi_register_master); | |
1494 | ||
666d5b4c MB |
1495 | static void devm_spi_unregister(struct device *dev, void *res) |
1496 | { | |
1497 | spi_unregister_master(*(struct spi_master **)res); | |
1498 | } | |
1499 | ||
1500 | /** | |
1501 | * dev_spi_register_master - register managed SPI master controller | |
1502 | * @dev: device managing SPI master | |
1503 | * @master: initialized master, originally from spi_alloc_master() | |
1504 | * Context: can sleep | |
1505 | * | |
1506 | * Register a SPI device as with spi_register_master() which will | |
1507 | * automatically be unregister | |
1508 | */ | |
1509 | int devm_spi_register_master(struct device *dev, struct spi_master *master) | |
1510 | { | |
1511 | struct spi_master **ptr; | |
1512 | int ret; | |
1513 | ||
1514 | ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL); | |
1515 | if (!ptr) | |
1516 | return -ENOMEM; | |
1517 | ||
1518 | ret = spi_register_master(master); | |
4b92894e | 1519 | if (!ret) { |
666d5b4c MB |
1520 | *ptr = master; |
1521 | devres_add(dev, ptr); | |
1522 | } else { | |
1523 | devres_free(ptr); | |
1524 | } | |
1525 | ||
1526 | return ret; | |
1527 | } | |
1528 | EXPORT_SYMBOL_GPL(devm_spi_register_master); | |
1529 | ||
34860089 | 1530 | static int __unregister(struct device *dev, void *null) |
8ae12a0d | 1531 | { |
34860089 | 1532 | spi_unregister_device(to_spi_device(dev)); |
8ae12a0d DB |
1533 | return 0; |
1534 | } | |
1535 | ||
1536 | /** | |
1537 | * spi_unregister_master - unregister SPI master controller | |
1538 | * @master: the master being unregistered | |
33e34dc6 | 1539 | * Context: can sleep |
8ae12a0d DB |
1540 | * |
1541 | * This call is used only by SPI master controller drivers, which are the | |
1542 | * only ones directly touching chip registers. | |
1543 | * | |
1544 | * This must be called from context that can sleep. | |
1545 | */ | |
1546 | void spi_unregister_master(struct spi_master *master) | |
1547 | { | |
89fc9a1a JG |
1548 | int dummy; |
1549 | ||
ffbbdd21 LW |
1550 | if (master->queued) { |
1551 | if (spi_destroy_queue(master)) | |
1552 | dev_err(&master->dev, "queue remove failed\n"); | |
1553 | } | |
1554 | ||
2b9603a0 FT |
1555 | mutex_lock(&board_lock); |
1556 | list_del(&master->list); | |
1557 | mutex_unlock(&board_lock); | |
1558 | ||
97dbf37d | 1559 | dummy = device_for_each_child(&master->dev, NULL, __unregister); |
49dce689 | 1560 | device_unregister(&master->dev); |
8ae12a0d DB |
1561 | } |
1562 | EXPORT_SYMBOL_GPL(spi_unregister_master); | |
1563 | ||
ffbbdd21 LW |
1564 | int spi_master_suspend(struct spi_master *master) |
1565 | { | |
1566 | int ret; | |
1567 | ||
1568 | /* Basically no-ops for non-queued masters */ | |
1569 | if (!master->queued) | |
1570 | return 0; | |
1571 | ||
1572 | ret = spi_stop_queue(master); | |
1573 | if (ret) | |
1574 | dev_err(&master->dev, "queue stop failed\n"); | |
1575 | ||
1576 | return ret; | |
1577 | } | |
1578 | EXPORT_SYMBOL_GPL(spi_master_suspend); | |
1579 | ||
1580 | int spi_master_resume(struct spi_master *master) | |
1581 | { | |
1582 | int ret; | |
1583 | ||
1584 | if (!master->queued) | |
1585 | return 0; | |
1586 | ||
1587 | ret = spi_start_queue(master); | |
1588 | if (ret) | |
1589 | dev_err(&master->dev, "queue restart failed\n"); | |
1590 | ||
1591 | return ret; | |
1592 | } | |
1593 | EXPORT_SYMBOL_GPL(spi_master_resume); | |
1594 | ||
9f3b795a | 1595 | static int __spi_master_match(struct device *dev, const void *data) |
5ed2c832 DY |
1596 | { |
1597 | struct spi_master *m; | |
9f3b795a | 1598 | const u16 *bus_num = data; |
5ed2c832 DY |
1599 | |
1600 | m = container_of(dev, struct spi_master, dev); | |
1601 | return m->bus_num == *bus_num; | |
1602 | } | |
1603 | ||
8ae12a0d DB |
1604 | /** |
1605 | * spi_busnum_to_master - look up master associated with bus_num | |
1606 | * @bus_num: the master's bus number | |
33e34dc6 | 1607 | * Context: can sleep |
8ae12a0d DB |
1608 | * |
1609 | * This call may be used with devices that are registered after | |
1610 | * arch init time. It returns a refcounted pointer to the relevant | |
1611 | * spi_master (which the caller must release), or NULL if there is | |
1612 | * no such master registered. | |
1613 | */ | |
1614 | struct spi_master *spi_busnum_to_master(u16 bus_num) | |
1615 | { | |
49dce689 | 1616 | struct device *dev; |
1e9a51dc | 1617 | struct spi_master *master = NULL; |
5ed2c832 | 1618 | |
695794ae | 1619 | dev = class_find_device(&spi_master_class, NULL, &bus_num, |
5ed2c832 DY |
1620 | __spi_master_match); |
1621 | if (dev) | |
1622 | master = container_of(dev, struct spi_master, dev); | |
1623 | /* reference got in class_find_device */ | |
1e9a51dc | 1624 | return master; |
8ae12a0d DB |
1625 | } |
1626 | EXPORT_SYMBOL_GPL(spi_busnum_to_master); | |
1627 | ||
1628 | ||
1629 | /*-------------------------------------------------------------------------*/ | |
1630 | ||
7d077197 DB |
1631 | /* Core methods for SPI master protocol drivers. Some of the |
1632 | * other core methods are currently defined as inline functions. | |
1633 | */ | |
1634 | ||
1635 | /** | |
1636 | * spi_setup - setup SPI mode and clock rate | |
1637 | * @spi: the device whose settings are being modified | |
1638 | * Context: can sleep, and no requests are queued to the device | |
1639 | * | |
1640 | * SPI protocol drivers may need to update the transfer mode if the | |
1641 | * device doesn't work with its default. They may likewise need | |
1642 | * to update clock rates or word sizes from initial values. This function | |
1643 | * changes those settings, and must be called from a context that can sleep. | |
1644 | * Except for SPI_CS_HIGH, which takes effect immediately, the changes take | |
1645 | * effect the next time the device is selected and data is transferred to | |
1646 | * or from it. When this function returns, the spi device is deselected. | |
1647 | * | |
1648 | * Note that this call will fail if the protocol driver specifies an option | |
1649 | * that the underlying controller or its driver does not support. For | |
1650 | * example, not all hardware supports wire transfers using nine bit words, | |
1651 | * LSB-first wire encoding, or active-high chipselects. | |
1652 | */ | |
1653 | int spi_setup(struct spi_device *spi) | |
1654 | { | |
e7db06b5 | 1655 | unsigned bad_bits; |
caae070c | 1656 | int status = 0; |
7d077197 | 1657 | |
f477b7fb | 1658 | /* check mode to prevent that DUAL and QUAD set at the same time |
1659 | */ | |
1660 | if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) || | |
1661 | ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) { | |
1662 | dev_err(&spi->dev, | |
1663 | "setup: can not select dual and quad at the same time\n"); | |
1664 | return -EINVAL; | |
1665 | } | |
1666 | /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden | |
1667 | */ | |
1668 | if ((spi->mode & SPI_3WIRE) && (spi->mode & | |
1669 | (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD))) | |
1670 | return -EINVAL; | |
e7db06b5 DB |
1671 | /* help drivers fail *cleanly* when they need options |
1672 | * that aren't supported with their current master | |
1673 | */ | |
1674 | bad_bits = spi->mode & ~spi->master->mode_bits; | |
1675 | if (bad_bits) { | |
eb288a1f | 1676 | dev_err(&spi->dev, "setup: unsupported mode bits %x\n", |
e7db06b5 DB |
1677 | bad_bits); |
1678 | return -EINVAL; | |
1679 | } | |
1680 | ||
7d077197 DB |
1681 | if (!spi->bits_per_word) |
1682 | spi->bits_per_word = 8; | |
1683 | ||
caae070c LD |
1684 | if (spi->master->setup) |
1685 | status = spi->master->setup(spi); | |
7d077197 | 1686 | |
5fe5f05e | 1687 | dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n", |
7d077197 DB |
1688 | (int) (spi->mode & (SPI_CPOL | SPI_CPHA)), |
1689 | (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "", | |
1690 | (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "", | |
1691 | (spi->mode & SPI_3WIRE) ? "3wire, " : "", | |
1692 | (spi->mode & SPI_LOOP) ? "loopback, " : "", | |
1693 | spi->bits_per_word, spi->max_speed_hz, | |
1694 | status); | |
1695 | ||
1696 | return status; | |
1697 | } | |
1698 | EXPORT_SYMBOL_GPL(spi_setup); | |
1699 | ||
90808738 | 1700 | static int __spi_validate(struct spi_device *spi, struct spi_message *message) |
cf32b71e ES |
1701 | { |
1702 | struct spi_master *master = spi->master; | |
e6811d1d | 1703 | struct spi_transfer *xfer; |
cf32b71e | 1704 | |
24a0013a MB |
1705 | if (list_empty(&message->transfers)) |
1706 | return -EINVAL; | |
1707 | if (!message->complete) | |
1708 | return -EINVAL; | |
1709 | ||
cf32b71e ES |
1710 | /* Half-duplex links include original MicroWire, and ones with |
1711 | * only one data pin like SPI_3WIRE (switches direction) or where | |
1712 | * either MOSI or MISO is missing. They can also be caused by | |
1713 | * software limitations. | |
1714 | */ | |
1715 | if ((master->flags & SPI_MASTER_HALF_DUPLEX) | |
1716 | || (spi->mode & SPI_3WIRE)) { | |
cf32b71e ES |
1717 | unsigned flags = master->flags; |
1718 | ||
1719 | list_for_each_entry(xfer, &message->transfers, transfer_list) { | |
1720 | if (xfer->rx_buf && xfer->tx_buf) | |
1721 | return -EINVAL; | |
1722 | if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf) | |
1723 | return -EINVAL; | |
1724 | if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf) | |
1725 | return -EINVAL; | |
1726 | } | |
1727 | } | |
1728 | ||
e6811d1d | 1729 | /** |
059b8ffe LD |
1730 | * Set transfer bits_per_word and max speed as spi device default if |
1731 | * it is not set for this transfer. | |
f477b7fb | 1732 | * Set transfer tx_nbits and rx_nbits as single transfer default |
1733 | * (SPI_NBITS_SINGLE) if it is not set for this transfer. | |
e6811d1d LD |
1734 | */ |
1735 | list_for_each_entry(xfer, &message->transfers, transfer_list) { | |
078726ce | 1736 | message->frame_length += xfer->len; |
e6811d1d LD |
1737 | if (!xfer->bits_per_word) |
1738 | xfer->bits_per_word = spi->bits_per_word; | |
56ede94a | 1739 | if (!xfer->speed_hz) { |
059b8ffe | 1740 | xfer->speed_hz = spi->max_speed_hz; |
56ede94a GJ |
1741 | if (master->max_speed_hz && |
1742 | xfer->speed_hz > master->max_speed_hz) | |
1743 | xfer->speed_hz = master->max_speed_hz; | |
1744 | } | |
1745 | ||
543bb255 SW |
1746 | if (master->bits_per_word_mask) { |
1747 | /* Only 32 bits fit in the mask */ | |
1748 | if (xfer->bits_per_word > 32) | |
1749 | return -EINVAL; | |
1750 | if (!(master->bits_per_word_mask & | |
1751 | BIT(xfer->bits_per_word - 1))) | |
1752 | return -EINVAL; | |
1753 | } | |
a2fd4f9f MB |
1754 | |
1755 | if (xfer->speed_hz && master->min_speed_hz && | |
1756 | xfer->speed_hz < master->min_speed_hz) | |
1757 | return -EINVAL; | |
1758 | if (xfer->speed_hz && master->max_speed_hz && | |
1759 | xfer->speed_hz > master->max_speed_hz) | |
d5ee722a | 1760 | return -EINVAL; |
f477b7fb | 1761 | |
1762 | if (xfer->tx_buf && !xfer->tx_nbits) | |
1763 | xfer->tx_nbits = SPI_NBITS_SINGLE; | |
1764 | if (xfer->rx_buf && !xfer->rx_nbits) | |
1765 | xfer->rx_nbits = SPI_NBITS_SINGLE; | |
1766 | /* check transfer tx/rx_nbits: | |
1afd9989 GU |
1767 | * 1. check the value matches one of single, dual and quad |
1768 | * 2. check tx/rx_nbits match the mode in spi_device | |
f477b7fb | 1769 | */ |
db90a441 SP |
1770 | if (xfer->tx_buf) { |
1771 | if (xfer->tx_nbits != SPI_NBITS_SINGLE && | |
1772 | xfer->tx_nbits != SPI_NBITS_DUAL && | |
1773 | xfer->tx_nbits != SPI_NBITS_QUAD) | |
1774 | return -EINVAL; | |
1775 | if ((xfer->tx_nbits == SPI_NBITS_DUAL) && | |
1776 | !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD))) | |
1777 | return -EINVAL; | |
1778 | if ((xfer->tx_nbits == SPI_NBITS_QUAD) && | |
1779 | !(spi->mode & SPI_TX_QUAD)) | |
1780 | return -EINVAL; | |
db90a441 | 1781 | } |
f477b7fb | 1782 | /* check transfer rx_nbits */ |
db90a441 SP |
1783 | if (xfer->rx_buf) { |
1784 | if (xfer->rx_nbits != SPI_NBITS_SINGLE && | |
1785 | xfer->rx_nbits != SPI_NBITS_DUAL && | |
1786 | xfer->rx_nbits != SPI_NBITS_QUAD) | |
1787 | return -EINVAL; | |
1788 | if ((xfer->rx_nbits == SPI_NBITS_DUAL) && | |
1789 | !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD))) | |
1790 | return -EINVAL; | |
1791 | if ((xfer->rx_nbits == SPI_NBITS_QUAD) && | |
1792 | !(spi->mode & SPI_RX_QUAD)) | |
1793 | return -EINVAL; | |
db90a441 | 1794 | } |
e6811d1d LD |
1795 | } |
1796 | ||
cf32b71e | 1797 | message->status = -EINPROGRESS; |
90808738 MB |
1798 | |
1799 | return 0; | |
1800 | } | |
1801 | ||
1802 | static int __spi_async(struct spi_device *spi, struct spi_message *message) | |
1803 | { | |
1804 | struct spi_master *master = spi->master; | |
1805 | ||
1806 | message->spi = spi; | |
1807 | ||
1808 | trace_spi_message_submit(message); | |
1809 | ||
cf32b71e ES |
1810 | return master->transfer(spi, message); |
1811 | } | |
1812 | ||
568d0697 DB |
1813 | /** |
1814 | * spi_async - asynchronous SPI transfer | |
1815 | * @spi: device with which data will be exchanged | |
1816 | * @message: describes the data transfers, including completion callback | |
1817 | * Context: any (irqs may be blocked, etc) | |
1818 | * | |
1819 | * This call may be used in_irq and other contexts which can't sleep, | |
1820 | * as well as from task contexts which can sleep. | |
1821 | * | |
1822 | * The completion callback is invoked in a context which can't sleep. | |
1823 | * Before that invocation, the value of message->status is undefined. | |
1824 | * When the callback is issued, message->status holds either zero (to | |
1825 | * indicate complete success) or a negative error code. After that | |
1826 | * callback returns, the driver which issued the transfer request may | |
1827 | * deallocate the associated memory; it's no longer in use by any SPI | |
1828 | * core or controller driver code. | |
1829 | * | |
1830 | * Note that although all messages to a spi_device are handled in | |
1831 | * FIFO order, messages may go to different devices in other orders. | |
1832 | * Some device might be higher priority, or have various "hard" access | |
1833 | * time requirements, for example. | |
1834 | * | |
1835 | * On detection of any fault during the transfer, processing of | |
1836 | * the entire message is aborted, and the device is deselected. | |
1837 | * Until returning from the associated message completion callback, | |
1838 | * no other spi_message queued to that device will be processed. | |
1839 | * (This rule applies equally to all the synchronous transfer calls, | |
1840 | * which are wrappers around this core asynchronous primitive.) | |
1841 | */ | |
1842 | int spi_async(struct spi_device *spi, struct spi_message *message) | |
1843 | { | |
1844 | struct spi_master *master = spi->master; | |
cf32b71e ES |
1845 | int ret; |
1846 | unsigned long flags; | |
568d0697 | 1847 | |
90808738 MB |
1848 | ret = __spi_validate(spi, message); |
1849 | if (ret != 0) | |
1850 | return ret; | |
1851 | ||
cf32b71e | 1852 | spin_lock_irqsave(&master->bus_lock_spinlock, flags); |
568d0697 | 1853 | |
cf32b71e ES |
1854 | if (master->bus_lock_flag) |
1855 | ret = -EBUSY; | |
1856 | else | |
1857 | ret = __spi_async(spi, message); | |
568d0697 | 1858 | |
cf32b71e ES |
1859 | spin_unlock_irqrestore(&master->bus_lock_spinlock, flags); |
1860 | ||
1861 | return ret; | |
568d0697 DB |
1862 | } |
1863 | EXPORT_SYMBOL_GPL(spi_async); | |
1864 | ||
cf32b71e ES |
1865 | /** |
1866 | * spi_async_locked - version of spi_async with exclusive bus usage | |
1867 | * @spi: device with which data will be exchanged | |
1868 | * @message: describes the data transfers, including completion callback | |
1869 | * Context: any (irqs may be blocked, etc) | |
1870 | * | |
1871 | * This call may be used in_irq and other contexts which can't sleep, | |
1872 | * as well as from task contexts which can sleep. | |
1873 | * | |
1874 | * The completion callback is invoked in a context which can't sleep. | |
1875 | * Before that invocation, the value of message->status is undefined. | |
1876 | * When the callback is issued, message->status holds either zero (to | |
1877 | * indicate complete success) or a negative error code. After that | |
1878 | * callback returns, the driver which issued the transfer request may | |
1879 | * deallocate the associated memory; it's no longer in use by any SPI | |
1880 | * core or controller driver code. | |
1881 | * | |
1882 | * Note that although all messages to a spi_device are handled in | |
1883 | * FIFO order, messages may go to different devices in other orders. | |
1884 | * Some device might be higher priority, or have various "hard" access | |
1885 | * time requirements, for example. | |
1886 | * | |
1887 | * On detection of any fault during the transfer, processing of | |
1888 | * the entire message is aborted, and the device is deselected. | |
1889 | * Until returning from the associated message completion callback, | |
1890 | * no other spi_message queued to that device will be processed. | |
1891 | * (This rule applies equally to all the synchronous transfer calls, | |
1892 | * which are wrappers around this core asynchronous primitive.) | |
1893 | */ | |
1894 | int spi_async_locked(struct spi_device *spi, struct spi_message *message) | |
1895 | { | |
1896 | struct spi_master *master = spi->master; | |
1897 | int ret; | |
1898 | unsigned long flags; | |
1899 | ||
90808738 MB |
1900 | ret = __spi_validate(spi, message); |
1901 | if (ret != 0) | |
1902 | return ret; | |
1903 | ||
cf32b71e ES |
1904 | spin_lock_irqsave(&master->bus_lock_spinlock, flags); |
1905 | ||
1906 | ret = __spi_async(spi, message); | |
1907 | ||
1908 | spin_unlock_irqrestore(&master->bus_lock_spinlock, flags); | |
1909 | ||
1910 | return ret; | |
1911 | ||
1912 | } | |
1913 | EXPORT_SYMBOL_GPL(spi_async_locked); | |
1914 | ||
7d077197 DB |
1915 | |
1916 | /*-------------------------------------------------------------------------*/ | |
1917 | ||
1918 | /* Utility methods for SPI master protocol drivers, layered on | |
1919 | * top of the core. Some other utility methods are defined as | |
1920 | * inline functions. | |
1921 | */ | |
1922 | ||
5d870c8e AM |
1923 | static void spi_complete(void *arg) |
1924 | { | |
1925 | complete(arg); | |
1926 | } | |
1927 | ||
cf32b71e ES |
1928 | static int __spi_sync(struct spi_device *spi, struct spi_message *message, |
1929 | int bus_locked) | |
1930 | { | |
1931 | DECLARE_COMPLETION_ONSTACK(done); | |
1932 | int status; | |
1933 | struct spi_master *master = spi->master; | |
1934 | ||
1935 | message->complete = spi_complete; | |
1936 | message->context = &done; | |
1937 | ||
1938 | if (!bus_locked) | |
1939 | mutex_lock(&master->bus_lock_mutex); | |
1940 | ||
1941 | status = spi_async_locked(spi, message); | |
1942 | ||
1943 | if (!bus_locked) | |
1944 | mutex_unlock(&master->bus_lock_mutex); | |
1945 | ||
1946 | if (status == 0) { | |
1947 | wait_for_completion(&done); | |
1948 | status = message->status; | |
1949 | } | |
1950 | message->context = NULL; | |
1951 | return status; | |
1952 | } | |
1953 | ||
8ae12a0d DB |
1954 | /** |
1955 | * spi_sync - blocking/synchronous SPI data transfers | |
1956 | * @spi: device with which data will be exchanged | |
1957 | * @message: describes the data transfers | |
33e34dc6 | 1958 | * Context: can sleep |
8ae12a0d DB |
1959 | * |
1960 | * This call may only be used from a context that may sleep. The sleep | |
1961 | * is non-interruptible, and has no timeout. Low-overhead controller | |
1962 | * drivers may DMA directly into and out of the message buffers. | |
1963 | * | |
1964 | * Note that the SPI device's chip select is active during the message, | |
1965 | * and then is normally disabled between messages. Drivers for some | |
1966 | * frequently-used devices may want to minimize costs of selecting a chip, | |
1967 | * by leaving it selected in anticipation that the next message will go | |
1968 | * to the same chip. (That may increase power usage.) | |
1969 | * | |
0c868461 DB |
1970 | * Also, the caller is guaranteeing that the memory associated with the |
1971 | * message will not be freed before this call returns. | |
1972 | * | |
9b938b74 | 1973 | * It returns zero on success, else a negative error code. |
8ae12a0d DB |
1974 | */ |
1975 | int spi_sync(struct spi_device *spi, struct spi_message *message) | |
1976 | { | |
cf32b71e | 1977 | return __spi_sync(spi, message, 0); |
8ae12a0d DB |
1978 | } |
1979 | EXPORT_SYMBOL_GPL(spi_sync); | |
1980 | ||
cf32b71e ES |
1981 | /** |
1982 | * spi_sync_locked - version of spi_sync with exclusive bus usage | |
1983 | * @spi: device with which data will be exchanged | |
1984 | * @message: describes the data transfers | |
1985 | * Context: can sleep | |
1986 | * | |
1987 | * This call may only be used from a context that may sleep. The sleep | |
1988 | * is non-interruptible, and has no timeout. Low-overhead controller | |
1989 | * drivers may DMA directly into and out of the message buffers. | |
1990 | * | |
1991 | * This call should be used by drivers that require exclusive access to the | |
25985edc | 1992 | * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must |
cf32b71e ES |
1993 | * be released by a spi_bus_unlock call when the exclusive access is over. |
1994 | * | |
1995 | * It returns zero on success, else a negative error code. | |
1996 | */ | |
1997 | int spi_sync_locked(struct spi_device *spi, struct spi_message *message) | |
1998 | { | |
1999 | return __spi_sync(spi, message, 1); | |
2000 | } | |
2001 | EXPORT_SYMBOL_GPL(spi_sync_locked); | |
2002 | ||
2003 | /** | |
2004 | * spi_bus_lock - obtain a lock for exclusive SPI bus usage | |
2005 | * @master: SPI bus master that should be locked for exclusive bus access | |
2006 | * Context: can sleep | |
2007 | * | |
2008 | * This call may only be used from a context that may sleep. The sleep | |
2009 | * is non-interruptible, and has no timeout. | |
2010 | * | |
2011 | * This call should be used by drivers that require exclusive access to the | |
2012 | * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the | |
2013 | * exclusive access is over. Data transfer must be done by spi_sync_locked | |
2014 | * and spi_async_locked calls when the SPI bus lock is held. | |
2015 | * | |
2016 | * It returns zero on success, else a negative error code. | |
2017 | */ | |
2018 | int spi_bus_lock(struct spi_master *master) | |
2019 | { | |
2020 | unsigned long flags; | |
2021 | ||
2022 | mutex_lock(&master->bus_lock_mutex); | |
2023 | ||
2024 | spin_lock_irqsave(&master->bus_lock_spinlock, flags); | |
2025 | master->bus_lock_flag = 1; | |
2026 | spin_unlock_irqrestore(&master->bus_lock_spinlock, flags); | |
2027 | ||
2028 | /* mutex remains locked until spi_bus_unlock is called */ | |
2029 | ||
2030 | return 0; | |
2031 | } | |
2032 | EXPORT_SYMBOL_GPL(spi_bus_lock); | |
2033 | ||
2034 | /** | |
2035 | * spi_bus_unlock - release the lock for exclusive SPI bus usage | |
2036 | * @master: SPI bus master that was locked for exclusive bus access | |
2037 | * Context: can sleep | |
2038 | * | |
2039 | * This call may only be used from a context that may sleep. The sleep | |
2040 | * is non-interruptible, and has no timeout. | |
2041 | * | |
2042 | * This call releases an SPI bus lock previously obtained by an spi_bus_lock | |
2043 | * call. | |
2044 | * | |
2045 | * It returns zero on success, else a negative error code. | |
2046 | */ | |
2047 | int spi_bus_unlock(struct spi_master *master) | |
2048 | { | |
2049 | master->bus_lock_flag = 0; | |
2050 | ||
2051 | mutex_unlock(&master->bus_lock_mutex); | |
2052 | ||
2053 | return 0; | |
2054 | } | |
2055 | EXPORT_SYMBOL_GPL(spi_bus_unlock); | |
2056 | ||
a9948b61 | 2057 | /* portable code must never pass more than 32 bytes */ |
5fe5f05e | 2058 | #define SPI_BUFSIZ max(32, SMP_CACHE_BYTES) |
8ae12a0d DB |
2059 | |
2060 | static u8 *buf; | |
2061 | ||
2062 | /** | |
2063 | * spi_write_then_read - SPI synchronous write followed by read | |
2064 | * @spi: device with which data will be exchanged | |
2065 | * @txbuf: data to be written (need not be dma-safe) | |
2066 | * @n_tx: size of txbuf, in bytes | |
27570497 JP |
2067 | * @rxbuf: buffer into which data will be read (need not be dma-safe) |
2068 | * @n_rx: size of rxbuf, in bytes | |
33e34dc6 | 2069 | * Context: can sleep |
8ae12a0d DB |
2070 | * |
2071 | * This performs a half duplex MicroWire style transaction with the | |
2072 | * device, sending txbuf and then reading rxbuf. The return value | |
2073 | * is zero for success, else a negative errno status code. | |
b885244e | 2074 | * This call may only be used from a context that may sleep. |
8ae12a0d | 2075 | * |
0c868461 | 2076 | * Parameters to this routine are always copied using a small buffer; |
33e34dc6 DB |
2077 | * portable code should never use this for more than 32 bytes. |
2078 | * Performance-sensitive or bulk transfer code should instead use | |
0c868461 | 2079 | * spi_{async,sync}() calls with dma-safe buffers. |
8ae12a0d DB |
2080 | */ |
2081 | int spi_write_then_read(struct spi_device *spi, | |
0c4a1590 MB |
2082 | const void *txbuf, unsigned n_tx, |
2083 | void *rxbuf, unsigned n_rx) | |
8ae12a0d | 2084 | { |
068f4070 | 2085 | static DEFINE_MUTEX(lock); |
8ae12a0d DB |
2086 | |
2087 | int status; | |
2088 | struct spi_message message; | |
bdff549e | 2089 | struct spi_transfer x[2]; |
8ae12a0d DB |
2090 | u8 *local_buf; |
2091 | ||
b3a223ee MB |
2092 | /* Use preallocated DMA-safe buffer if we can. We can't avoid |
2093 | * copying here, (as a pure convenience thing), but we can | |
2094 | * keep heap costs out of the hot path unless someone else is | |
2095 | * using the pre-allocated buffer or the transfer is too large. | |
8ae12a0d | 2096 | */ |
b3a223ee | 2097 | if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) { |
2cd94c8a MB |
2098 | local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx), |
2099 | GFP_KERNEL | GFP_DMA); | |
b3a223ee MB |
2100 | if (!local_buf) |
2101 | return -ENOMEM; | |
2102 | } else { | |
2103 | local_buf = buf; | |
2104 | } | |
8ae12a0d | 2105 | |
8275c642 | 2106 | spi_message_init(&message); |
5fe5f05e | 2107 | memset(x, 0, sizeof(x)); |
bdff549e DB |
2108 | if (n_tx) { |
2109 | x[0].len = n_tx; | |
2110 | spi_message_add_tail(&x[0], &message); | |
2111 | } | |
2112 | if (n_rx) { | |
2113 | x[1].len = n_rx; | |
2114 | spi_message_add_tail(&x[1], &message); | |
2115 | } | |
8275c642 | 2116 | |
8ae12a0d | 2117 | memcpy(local_buf, txbuf, n_tx); |
bdff549e DB |
2118 | x[0].tx_buf = local_buf; |
2119 | x[1].rx_buf = local_buf + n_tx; | |
8ae12a0d DB |
2120 | |
2121 | /* do the i/o */ | |
8ae12a0d | 2122 | status = spi_sync(spi, &message); |
9b938b74 | 2123 | if (status == 0) |
bdff549e | 2124 | memcpy(rxbuf, x[1].rx_buf, n_rx); |
8ae12a0d | 2125 | |
bdff549e | 2126 | if (x[0].tx_buf == buf) |
068f4070 | 2127 | mutex_unlock(&lock); |
8ae12a0d DB |
2128 | else |
2129 | kfree(local_buf); | |
2130 | ||
2131 | return status; | |
2132 | } | |
2133 | EXPORT_SYMBOL_GPL(spi_write_then_read); | |
2134 | ||
2135 | /*-------------------------------------------------------------------------*/ | |
2136 | ||
2137 | static int __init spi_init(void) | |
2138 | { | |
b885244e DB |
2139 | int status; |
2140 | ||
e94b1766 | 2141 | buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL); |
b885244e DB |
2142 | if (!buf) { |
2143 | status = -ENOMEM; | |
2144 | goto err0; | |
2145 | } | |
2146 | ||
2147 | status = bus_register(&spi_bus_type); | |
2148 | if (status < 0) | |
2149 | goto err1; | |
8ae12a0d | 2150 | |
b885244e DB |
2151 | status = class_register(&spi_master_class); |
2152 | if (status < 0) | |
2153 | goto err2; | |
8ae12a0d | 2154 | return 0; |
b885244e DB |
2155 | |
2156 | err2: | |
2157 | bus_unregister(&spi_bus_type); | |
2158 | err1: | |
2159 | kfree(buf); | |
2160 | buf = NULL; | |
2161 | err0: | |
2162 | return status; | |
8ae12a0d | 2163 | } |
b885244e | 2164 | |
8ae12a0d DB |
2165 | /* board_info is normally registered in arch_initcall(), |
2166 | * but even essential drivers wait till later | |
b885244e DB |
2167 | * |
2168 | * REVISIT only boardinfo really needs static linking. the rest (device and | |
2169 | * driver registration) _could_ be dynamically linked (modular) ... costs | |
2170 | * include needing to have boardinfo data structures be much more public. | |
8ae12a0d | 2171 | */ |
673c0c00 | 2172 | postcore_initcall(spi_init); |
8ae12a0d | 2173 |