blob: 82b9a428c323eab0a0ea2fa4d8f033ba67025ee5 [file] [log] [blame]
David Brownell8ae12a02006-01-08 13:34:19 -08001/*
2 * spi.c - SPI init/core code
3 *
4 * Copyright (C) 2005 David Brownell
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19 */
20
David Brownell8ae12a02006-01-08 13:34:19 -080021#include <linux/kernel.h>
22#include <linux/device.h>
23#include <linux/init.h>
24#include <linux/cache.h>
Matthias Kaehlcke94040822007-07-17 04:04:16 -070025#include <linux/mutex.h>
Sinan Akman2b7a32f2010-10-02 21:28:29 -060026#include <linux/of_device.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090027#include <linux/slab.h>
Anton Vorontsove0626e32009-09-22 16:46:08 -070028#include <linux/mod_devicetable.h>
David Brownell8ae12a02006-01-08 13:34:19 -080029#include <linux/spi/spi.h>
Anatolij Gustschin12b15e82010-07-27 22:35:58 +020030#include <linux/of_spi.h>
Mark Brown3ae22e82010-12-25 15:32:27 +010031#include <linux/pm_runtime.h>
David Brownell8ae12a02006-01-08 13:34:19 -080032
David Brownell8ae12a02006-01-08 13:34:19 -080033static void spidev_release(struct device *dev)
34{
Hans-Peter Nilsson0ffa0282007-02-12 00:52:45 -080035 struct spi_device *spi = to_spi_device(dev);
David Brownell8ae12a02006-01-08 13:34:19 -080036
37 /* spi masters may cleanup for released devices */
38 if (spi->master->cleanup)
39 spi->master->cleanup(spi);
40
David Brownell0c868462006-01-08 13:34:25 -080041 spi_master_put(spi->master);
Roman Tereshonkov07a389f2010-04-12 09:56:35 +000042 kfree(spi);
David Brownell8ae12a02006-01-08 13:34:19 -080043}
44
45static ssize_t
46modalias_show(struct device *dev, struct device_attribute *a, char *buf)
47{
48 const struct spi_device *spi = to_spi_device(dev);
49
Kay Sievers35f74fc2009-01-06 10:44:37 -080050 return sprintf(buf, "%s\n", spi->modalias);
David Brownell8ae12a02006-01-08 13:34:19 -080051}
52
53static struct device_attribute spi_dev_attrs[] = {
54 __ATTR_RO(modalias),
55 __ATTR_NULL,
56};
57
58/* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
59 * and the sysfs version makes coldplug work too.
60 */
61
Anton Vorontsov75368bf2009-09-22 16:46:04 -070062static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
63 const struct spi_device *sdev)
64{
65 while (id->name[0]) {
66 if (!strcmp(sdev->modalias, id->name))
67 return id;
68 id++;
69 }
70 return NULL;
71}
72
73const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
74{
75 const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
76
77 return spi_match_id(sdrv->id_table, sdev);
78}
79EXPORT_SYMBOL_GPL(spi_get_device_id);
80
David Brownell8ae12a02006-01-08 13:34:19 -080081static int spi_match_device(struct device *dev, struct device_driver *drv)
82{
83 const struct spi_device *spi = to_spi_device(dev);
Anton Vorontsov75368bf2009-09-22 16:46:04 -070084 const struct spi_driver *sdrv = to_spi_driver(drv);
85
Sinan Akman2b7a32f2010-10-02 21:28:29 -060086 /* Attempt an OF style match */
87 if (of_driver_match_device(dev, drv))
88 return 1;
89
Anton Vorontsov75368bf2009-09-22 16:46:04 -070090 if (sdrv->id_table)
91 return !!spi_match_id(sdrv->id_table, spi);
David Brownell8ae12a02006-01-08 13:34:19 -080092
Kay Sievers35f74fc2009-01-06 10:44:37 -080093 return strcmp(spi->modalias, drv->name) == 0;
David Brownell8ae12a02006-01-08 13:34:19 -080094}
95
Kay Sievers7eff2e72007-08-14 15:15:12 +020096static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
David Brownell8ae12a02006-01-08 13:34:19 -080097{
98 const struct spi_device *spi = to_spi_device(dev);
99
Anton Vorontsove0626e32009-09-22 16:46:08 -0700100 add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
David Brownell8ae12a02006-01-08 13:34:19 -0800101 return 0;
102}
103
Mark Brown3ae22e82010-12-25 15:32:27 +0100104#ifdef CONFIG_PM_SLEEP
105static int spi_legacy_suspend(struct device *dev, pm_message_t message)
David Brownell8ae12a02006-01-08 13:34:19 -0800106{
David Brownell3c724262008-02-06 01:38:10 -0800107 int value = 0;
David Brownellb8852442006-01-08 13:34:23 -0800108 struct spi_driver *drv = to_spi_driver(dev->driver);
David Brownell8ae12a02006-01-08 13:34:19 -0800109
David Brownell8ae12a02006-01-08 13:34:19 -0800110 /* suspend will stop irqs and dma; no more i/o */
David Brownell3c724262008-02-06 01:38:10 -0800111 if (drv) {
112 if (drv->suspend)
113 value = drv->suspend(to_spi_device(dev), message);
114 else
115 dev_dbg(dev, "... can't suspend\n");
116 }
David Brownell8ae12a02006-01-08 13:34:19 -0800117 return value;
118}
119
Mark Brown3ae22e82010-12-25 15:32:27 +0100120static int spi_legacy_resume(struct device *dev)
David Brownell8ae12a02006-01-08 13:34:19 -0800121{
David Brownell3c724262008-02-06 01:38:10 -0800122 int value = 0;
David Brownellb8852442006-01-08 13:34:23 -0800123 struct spi_driver *drv = to_spi_driver(dev->driver);
David Brownell8ae12a02006-01-08 13:34:19 -0800124
David Brownell8ae12a02006-01-08 13:34:19 -0800125 /* resume may restart the i/o queue */
David Brownell3c724262008-02-06 01:38:10 -0800126 if (drv) {
127 if (drv->resume)
128 value = drv->resume(to_spi_device(dev));
129 else
130 dev_dbg(dev, "... can't resume\n");
131 }
David Brownell8ae12a02006-01-08 13:34:19 -0800132 return value;
133}
134
Mark Brown3ae22e82010-12-25 15:32:27 +0100135static int spi_pm_suspend(struct device *dev)
136{
137 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
138
139 if (pm)
140 return pm_generic_suspend(dev);
141 else
142 return spi_legacy_suspend(dev, PMSG_SUSPEND);
143}
144
145static int spi_pm_resume(struct device *dev)
146{
147 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
148
149 if (pm)
150 return pm_generic_resume(dev);
151 else
152 return spi_legacy_resume(dev);
153}
154
155static int spi_pm_freeze(struct device *dev)
156{
157 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
158
159 if (pm)
160 return pm_generic_freeze(dev);
161 else
162 return spi_legacy_suspend(dev, PMSG_FREEZE);
163}
164
165static int spi_pm_thaw(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_thaw(dev);
171 else
172 return spi_legacy_resume(dev);
173}
174
175static int spi_pm_poweroff(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_poweroff(dev);
181 else
182 return spi_legacy_suspend(dev, PMSG_HIBERNATE);
183}
184
185static int spi_pm_restore(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_restore(dev);
191 else
192 return spi_legacy_resume(dev);
193}
David Brownell8ae12a02006-01-08 13:34:19 -0800194#else
Mark Brown3ae22e82010-12-25 15:32:27 +0100195#define spi_pm_suspend NULL
196#define spi_pm_resume NULL
197#define spi_pm_freeze NULL
198#define spi_pm_thaw NULL
199#define spi_pm_poweroff NULL
200#define spi_pm_restore NULL
David Brownell8ae12a02006-01-08 13:34:19 -0800201#endif
202
Mark Brown3ae22e82010-12-25 15:32:27 +0100203static const struct dev_pm_ops spi_pm = {
204 .suspend = spi_pm_suspend,
205 .resume = spi_pm_resume,
206 .freeze = spi_pm_freeze,
207 .thaw = spi_pm_thaw,
208 .poweroff = spi_pm_poweroff,
209 .restore = spi_pm_restore,
210 SET_RUNTIME_PM_OPS(
211 pm_generic_runtime_suspend,
212 pm_generic_runtime_resume,
213 pm_generic_runtime_idle
214 )
215};
216
David Brownell8ae12a02006-01-08 13:34:19 -0800217struct bus_type spi_bus_type = {
218 .name = "spi",
219 .dev_attrs = spi_dev_attrs,
220 .match = spi_match_device,
221 .uevent = spi_uevent,
Mark Brown3ae22e82010-12-25 15:32:27 +0100222 .pm = &spi_pm,
David Brownell8ae12a02006-01-08 13:34:19 -0800223};
224EXPORT_SYMBOL_GPL(spi_bus_type);
225
David Brownellb8852442006-01-08 13:34:23 -0800226
227static int spi_drv_probe(struct device *dev)
228{
229 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
230
231 return sdrv->probe(to_spi_device(dev));
232}
233
234static int spi_drv_remove(struct device *dev)
235{
236 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
237
238 return sdrv->remove(to_spi_device(dev));
239}
240
241static void spi_drv_shutdown(struct device *dev)
242{
243 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
244
245 sdrv->shutdown(to_spi_device(dev));
246}
247
David Brownell33e34dc2007-05-08 00:32:21 -0700248/**
249 * spi_register_driver - register a SPI driver
250 * @sdrv: the driver to register
251 * Context: can sleep
252 */
David Brownellb8852442006-01-08 13:34:23 -0800253int spi_register_driver(struct spi_driver *sdrv)
254{
255 sdrv->driver.bus = &spi_bus_type;
256 if (sdrv->probe)
257 sdrv->driver.probe = spi_drv_probe;
258 if (sdrv->remove)
259 sdrv->driver.remove = spi_drv_remove;
260 if (sdrv->shutdown)
261 sdrv->driver.shutdown = spi_drv_shutdown;
262 return driver_register(&sdrv->driver);
263}
264EXPORT_SYMBOL_GPL(spi_register_driver);
265
David Brownell8ae12a02006-01-08 13:34:19 -0800266/*-------------------------------------------------------------------------*/
267
268/* SPI devices should normally not be created by SPI device drivers; that
269 * would make them board-specific. Similarly with SPI master drivers.
270 * Device registration normally goes into like arch/.../mach.../board-YYY.c
271 * with other readonly (flashable) information about mainboard devices.
272 */
273
274struct boardinfo {
275 struct list_head list;
Feng Tang2b9603a2010-08-02 15:52:15 +0800276 struct spi_board_info board_info;
David Brownell8ae12a02006-01-08 13:34:19 -0800277};
278
279static LIST_HEAD(board_list);
Feng Tang2b9603a2010-08-02 15:52:15 +0800280static LIST_HEAD(spi_master_list);
281
282/*
283 * Used to protect add/del opertion for board_info list and
284 * spi_master list, and their matching process
285 */
Matthias Kaehlcke94040822007-07-17 04:04:16 -0700286static DEFINE_MUTEX(board_lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800287
Grant Likelydc87c982008-05-15 16:50:22 -0600288/**
289 * spi_alloc_device - Allocate a new SPI device
290 * @master: Controller to which device is connected
291 * Context: can sleep
292 *
293 * Allows a driver to allocate and initialize a spi_device without
294 * registering it immediately. This allows a driver to directly
295 * fill the spi_device with device parameters before calling
296 * spi_add_device() on it.
297 *
298 * Caller is responsible to call spi_add_device() on the returned
299 * spi_device structure to add it to the SPI master. If the caller
300 * needs to discard the spi_device without adding it, then it should
301 * call spi_dev_put() on it.
302 *
303 * Returns a pointer to the new device, or NULL.
304 */
305struct spi_device *spi_alloc_device(struct spi_master *master)
306{
307 struct spi_device *spi;
308 struct device *dev = master->dev.parent;
309
310 if (!spi_master_get(master))
311 return NULL;
312
313 spi = kzalloc(sizeof *spi, GFP_KERNEL);
314 if (!spi) {
315 dev_err(dev, "cannot alloc spi_device\n");
316 spi_master_put(master);
317 return NULL;
318 }
319
320 spi->master = master;
321 spi->dev.parent = dev;
322 spi->dev.bus = &spi_bus_type;
323 spi->dev.release = spidev_release;
324 device_initialize(&spi->dev);
325 return spi;
326}
327EXPORT_SYMBOL_GPL(spi_alloc_device);
328
329/**
330 * spi_add_device - Add spi_device allocated with spi_alloc_device
331 * @spi: spi_device to register
332 *
333 * Companion function to spi_alloc_device. Devices allocated with
334 * spi_alloc_device can be added onto the spi bus with this function.
335 *
David Brownelle48880e2008-08-15 00:40:44 -0700336 * Returns 0 on success; negative errno on failure
Grant Likelydc87c982008-05-15 16:50:22 -0600337 */
338int spi_add_device(struct spi_device *spi)
339{
David Brownelle48880e2008-08-15 00:40:44 -0700340 static DEFINE_MUTEX(spi_add_lock);
Grant Likelydc87c982008-05-15 16:50:22 -0600341 struct device *dev = spi->master->dev.parent;
Roman Tereshonkov8ec130a2010-04-16 09:52:59 +0000342 struct device *d;
Grant Likelydc87c982008-05-15 16:50:22 -0600343 int status;
344
345 /* Chipselects are numbered 0..max; validate. */
346 if (spi->chip_select >= spi->master->num_chipselect) {
347 dev_err(dev, "cs%d >= max %d\n",
348 spi->chip_select,
349 spi->master->num_chipselect);
350 return -EINVAL;
351 }
352
353 /* Set the bus ID string */
Kay Sievers35f74fc2009-01-06 10:44:37 -0800354 dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
Grant Likelydc87c982008-05-15 16:50:22 -0600355 spi->chip_select);
356
David Brownelle48880e2008-08-15 00:40:44 -0700357
358 /* We need to make sure there's no other device with this
359 * chipselect **BEFORE** we call setup(), else we'll trash
360 * its configuration. Lock against concurrent add() calls.
361 */
362 mutex_lock(&spi_add_lock);
363
Roman Tereshonkov8ec130a2010-04-16 09:52:59 +0000364 d = bus_find_device_by_name(&spi_bus_type, NULL, dev_name(&spi->dev));
365 if (d != NULL) {
David Brownelle48880e2008-08-15 00:40:44 -0700366 dev_err(dev, "chipselect %d already in use\n",
367 spi->chip_select);
Roman Tereshonkov8ec130a2010-04-16 09:52:59 +0000368 put_device(d);
David Brownelle48880e2008-08-15 00:40:44 -0700369 status = -EBUSY;
370 goto done;
371 }
372
373 /* Drivers may modify this initial i/o setup, but will
374 * normally rely on the device being setup. Devices
375 * using SPI_CS_HIGH can't coexist well otherwise...
376 */
David Brownell7d077192009-06-17 16:26:03 -0700377 status = spi_setup(spi);
Grant Likelydc87c982008-05-15 16:50:22 -0600378 if (status < 0) {
Linus Walleijeb288a12010-10-21 21:06:44 +0200379 dev_err(dev, "can't setup %s, status %d\n",
380 dev_name(&spi->dev), status);
David Brownelle48880e2008-08-15 00:40:44 -0700381 goto done;
Grant Likelydc87c982008-05-15 16:50:22 -0600382 }
383
David Brownelle48880e2008-08-15 00:40:44 -0700384 /* Device may be bound to an active driver when this returns */
Grant Likelydc87c982008-05-15 16:50:22 -0600385 status = device_add(&spi->dev);
David Brownelle48880e2008-08-15 00:40:44 -0700386 if (status < 0)
Linus Walleijeb288a12010-10-21 21:06:44 +0200387 dev_err(dev, "can't add %s, status %d\n",
388 dev_name(&spi->dev), status);
David Brownelle48880e2008-08-15 00:40:44 -0700389 else
Kay Sievers35f74fc2009-01-06 10:44:37 -0800390 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
Grant Likelydc87c982008-05-15 16:50:22 -0600391
David Brownelle48880e2008-08-15 00:40:44 -0700392done:
393 mutex_unlock(&spi_add_lock);
394 return status;
Grant Likelydc87c982008-05-15 16:50:22 -0600395}
396EXPORT_SYMBOL_GPL(spi_add_device);
David Brownell8ae12a02006-01-08 13:34:19 -0800397
David Brownell33e34dc2007-05-08 00:32:21 -0700398/**
399 * spi_new_device - instantiate one new SPI device
400 * @master: Controller to which device is connected
401 * @chip: Describes the SPI device
402 * Context: can sleep
403 *
404 * On typical mainboards, this is purely internal; and it's not needed
David Brownell8ae12a02006-01-08 13:34:19 -0800405 * after board init creates the hard-wired devices. Some development
406 * platforms may not be able to use spi_register_board_info though, and
407 * this is exported so that for example a USB or parport based adapter
408 * driver could add devices (which it would learn about out-of-band).
David Brownell082c8cb2007-07-31 00:39:45 -0700409 *
410 * Returns the new device, or NULL.
David Brownell8ae12a02006-01-08 13:34:19 -0800411 */
Adrian Bunke9d5a462007-03-26 21:32:23 -0800412struct spi_device *spi_new_device(struct spi_master *master,
413 struct spi_board_info *chip)
David Brownell8ae12a02006-01-08 13:34:19 -0800414{
415 struct spi_device *proxy;
David Brownell8ae12a02006-01-08 13:34:19 -0800416 int status;
417
David Brownell082c8cb2007-07-31 00:39:45 -0700418 /* NOTE: caller did any chip->bus_num checks necessary.
419 *
420 * Also, unless we change the return value convention to use
421 * error-or-pointer (not NULL-or-pointer), troubleshootability
422 * suggests syslogged diagnostics are best here (ugh).
423 */
424
Grant Likelydc87c982008-05-15 16:50:22 -0600425 proxy = spi_alloc_device(master);
426 if (!proxy)
David Brownell8ae12a02006-01-08 13:34:19 -0800427 return NULL;
428
Grant Likely102eb972008-07-23 21:29:55 -0700429 WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
430
David Brownell8ae12a02006-01-08 13:34:19 -0800431 proxy->chip_select = chip->chip_select;
432 proxy->max_speed_hz = chip->max_speed_hz;
David Brownell980a01c2006-06-28 07:47:15 -0700433 proxy->mode = chip->mode;
David Brownell8ae12a02006-01-08 13:34:19 -0800434 proxy->irq = chip->irq;
Grant Likely102eb972008-07-23 21:29:55 -0700435 strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
David Brownell8ae12a02006-01-08 13:34:19 -0800436 proxy->dev.platform_data = (void *) chip->platform_data;
437 proxy->controller_data = chip->controller_data;
438 proxy->controller_state = NULL;
David Brownell8ae12a02006-01-08 13:34:19 -0800439
Grant Likelydc87c982008-05-15 16:50:22 -0600440 status = spi_add_device(proxy);
David Brownell8ae12a02006-01-08 13:34:19 -0800441 if (status < 0) {
Grant Likelydc87c982008-05-15 16:50:22 -0600442 spi_dev_put(proxy);
443 return NULL;
David Brownell8ae12a02006-01-08 13:34:19 -0800444 }
445
David Brownell8ae12a02006-01-08 13:34:19 -0800446 return proxy;
447}
448EXPORT_SYMBOL_GPL(spi_new_device);
449
Feng Tang2b9603a2010-08-02 15:52:15 +0800450static void spi_match_master_to_boardinfo(struct spi_master *master,
451 struct spi_board_info *bi)
452{
453 struct spi_device *dev;
454
455 if (master->bus_num != bi->bus_num)
456 return;
457
458 dev = spi_new_device(master, bi);
459 if (!dev)
460 dev_err(master->dev.parent, "can't create new device for %s\n",
461 bi->modalias);
462}
463
David Brownell33e34dc2007-05-08 00:32:21 -0700464/**
465 * spi_register_board_info - register SPI devices for a given board
466 * @info: array of chip descriptors
467 * @n: how many descriptors are provided
468 * Context: can sleep
469 *
David Brownell8ae12a02006-01-08 13:34:19 -0800470 * Board-specific early init code calls this (probably during arch_initcall)
471 * with segments of the SPI device table. Any device nodes are created later,
472 * after the relevant parent SPI controller (bus_num) is defined. We keep
473 * this table of devices forever, so that reloading a controller driver will
474 * not make Linux forget about these hard-wired devices.
475 *
476 * Other code can also call this, e.g. a particular add-on board might provide
477 * SPI devices through its expansion connector, so code initializing that board
478 * would naturally declare its SPI devices.
479 *
480 * The board info passed can safely be __initdata ... but be careful of
481 * any embedded pointers (platform_data, etc), they're copied as-is.
482 */
483int __init
484spi_register_board_info(struct spi_board_info const *info, unsigned n)
485{
Feng Tang2b9603a2010-08-02 15:52:15 +0800486 struct boardinfo *bi;
487 int i;
David Brownell8ae12a02006-01-08 13:34:19 -0800488
Feng Tang2b9603a2010-08-02 15:52:15 +0800489 bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
David Brownell8ae12a02006-01-08 13:34:19 -0800490 if (!bi)
491 return -ENOMEM;
David Brownell8ae12a02006-01-08 13:34:19 -0800492
Feng Tang2b9603a2010-08-02 15:52:15 +0800493 for (i = 0; i < n; i++, bi++, info++) {
494 struct spi_master *master;
David Brownell8ae12a02006-01-08 13:34:19 -0800495
Feng Tang2b9603a2010-08-02 15:52:15 +0800496 memcpy(&bi->board_info, info, sizeof(*info));
497 mutex_lock(&board_lock);
498 list_add_tail(&bi->list, &board_list);
499 list_for_each_entry(master, &spi_master_list, list)
500 spi_match_master_to_boardinfo(master, &bi->board_info);
501 mutex_unlock(&board_lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800502 }
Feng Tang2b9603a2010-08-02 15:52:15 +0800503
504 return 0;
David Brownell8ae12a02006-01-08 13:34:19 -0800505}
506
507/*-------------------------------------------------------------------------*/
508
Tony Jones49dce682007-10-16 01:27:48 -0700509static void spi_master_release(struct device *dev)
David Brownell8ae12a02006-01-08 13:34:19 -0800510{
511 struct spi_master *master;
512
Tony Jones49dce682007-10-16 01:27:48 -0700513 master = container_of(dev, struct spi_master, dev);
David Brownell8ae12a02006-01-08 13:34:19 -0800514 kfree(master);
515}
516
517static struct class spi_master_class = {
518 .name = "spi_master",
519 .owner = THIS_MODULE,
Tony Jones49dce682007-10-16 01:27:48 -0700520 .dev_release = spi_master_release,
David Brownell8ae12a02006-01-08 13:34:19 -0800521};
522
523
524/**
525 * spi_alloc_master - allocate SPI master controller
526 * @dev: the controller, possibly using the platform_bus
David Brownell33e34dc2007-05-08 00:32:21 -0700527 * @size: how much zeroed driver-private data to allocate; the pointer to this
Tony Jones49dce682007-10-16 01:27:48 -0700528 * memory is in the driver_data field of the returned device,
David Brownell0c868462006-01-08 13:34:25 -0800529 * accessible with spi_master_get_devdata().
David Brownell33e34dc2007-05-08 00:32:21 -0700530 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800531 *
532 * This call is used only by SPI master controller drivers, which are the
533 * only ones directly touching chip registers. It's how they allocate
dmitry pervushinba1a0512006-05-20 15:00:14 -0700534 * an spi_master structure, prior to calling spi_register_master().
David Brownell8ae12a02006-01-08 13:34:19 -0800535 *
536 * This must be called from context that can sleep. It returns the SPI
537 * master structure on success, else NULL.
538 *
539 * The caller is responsible for assigning the bus number and initializing
dmitry pervushinba1a0512006-05-20 15:00:14 -0700540 * the master's methods before calling spi_register_master(); and (after errors
David Brownell0c868462006-01-08 13:34:25 -0800541 * adding the device) calling spi_master_put() to prevent a memory leak.
David Brownell8ae12a02006-01-08 13:34:19 -0800542 */
Adrian Bunke9d5a462007-03-26 21:32:23 -0800543struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
David Brownell8ae12a02006-01-08 13:34:19 -0800544{
545 struct spi_master *master;
546
David Brownell0c868462006-01-08 13:34:25 -0800547 if (!dev)
548 return NULL;
549
Christoph Lametere94b1762006-12-06 20:33:17 -0800550 master = kzalloc(size + sizeof *master, GFP_KERNEL);
David Brownell8ae12a02006-01-08 13:34:19 -0800551 if (!master)
552 return NULL;
553
Tony Jones49dce682007-10-16 01:27:48 -0700554 device_initialize(&master->dev);
555 master->dev.class = &spi_master_class;
556 master->dev.parent = get_device(dev);
David Brownell0c868462006-01-08 13:34:25 -0800557 spi_master_set_devdata(master, &master[1]);
David Brownell8ae12a02006-01-08 13:34:19 -0800558
559 return master;
560}
561EXPORT_SYMBOL_GPL(spi_alloc_master);
562
563/**
564 * spi_register_master - register SPI master controller
565 * @master: initialized master, originally from spi_alloc_master()
David Brownell33e34dc2007-05-08 00:32:21 -0700566 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800567 *
568 * SPI master controllers connect to their drivers using some non-SPI bus,
569 * such as the platform bus. The final stage of probe() in that code
570 * includes calling spi_register_master() to hook up to this SPI bus glue.
571 *
572 * SPI controllers use board specific (often SOC specific) bus numbers,
573 * and board-specific addressing for SPI devices combines those numbers
574 * with chip select numbers. Since SPI does not directly support dynamic
575 * device identification, boards need configuration tables telling which
576 * chip is at which address.
577 *
578 * This must be called from context that can sleep. It returns zero on
579 * success, else a negative error code (dropping the master's refcount).
David Brownell0c868462006-01-08 13:34:25 -0800580 * After a successful return, the caller is responsible for calling
581 * spi_unregister_master().
David Brownell8ae12a02006-01-08 13:34:19 -0800582 */
Adrian Bunke9d5a462007-03-26 21:32:23 -0800583int spi_register_master(struct spi_master *master)
David Brownell8ae12a02006-01-08 13:34:19 -0800584{
David Brownelle44a45a2007-06-03 13:50:40 -0700585 static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
Tony Jones49dce682007-10-16 01:27:48 -0700586 struct device *dev = master->dev.parent;
Feng Tang2b9603a2010-08-02 15:52:15 +0800587 struct boardinfo *bi;
David Brownell8ae12a02006-01-08 13:34:19 -0800588 int status = -ENODEV;
589 int dynamic = 0;
590
David Brownell0c868462006-01-08 13:34:25 -0800591 if (!dev)
592 return -ENODEV;
593
David Brownell082c8cb2007-07-31 00:39:45 -0700594 /* even if it's just one always-selected device, there must
595 * be at least one chipselect
596 */
597 if (master->num_chipselect == 0)
598 return -EINVAL;
599
David Brownell8ae12a02006-01-08 13:34:19 -0800600 /* convention: dynamically assigned bus IDs count down from the max */
David Brownella020ed72006-04-03 15:49:04 -0700601 if (master->bus_num < 0) {
David Brownell082c8cb2007-07-31 00:39:45 -0700602 /* FIXME switch to an IDR based scheme, something like
603 * I2C now uses, so we can't run out of "dynamic" IDs
604 */
David Brownell8ae12a02006-01-08 13:34:19 -0800605 master->bus_num = atomic_dec_return(&dyn_bus_id);
David Brownellb8852442006-01-08 13:34:23 -0800606 dynamic = 1;
David Brownell8ae12a02006-01-08 13:34:19 -0800607 }
608
Ernst Schwabcf32b712010-06-28 17:49:29 -0700609 spin_lock_init(&master->bus_lock_spinlock);
610 mutex_init(&master->bus_lock_mutex);
611 master->bus_lock_flag = 0;
612
David Brownell8ae12a02006-01-08 13:34:19 -0800613 /* register the device, then userspace will see it.
614 * registration fails if the bus ID is in use.
615 */
Kay Sievers35f74fc2009-01-06 10:44:37 -0800616 dev_set_name(&master->dev, "spi%u", master->bus_num);
Tony Jones49dce682007-10-16 01:27:48 -0700617 status = device_add(&master->dev);
David Brownellb8852442006-01-08 13:34:23 -0800618 if (status < 0)
David Brownell8ae12a02006-01-08 13:34:19 -0800619 goto done;
Kay Sievers35f74fc2009-01-06 10:44:37 -0800620 dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
David Brownell8ae12a02006-01-08 13:34:19 -0800621 dynamic ? " (dynamic)" : "");
622
Feng Tang2b9603a2010-08-02 15:52:15 +0800623 mutex_lock(&board_lock);
624 list_add_tail(&master->list, &spi_master_list);
625 list_for_each_entry(bi, &board_list, list)
626 spi_match_master_to_boardinfo(master, &bi->board_info);
627 mutex_unlock(&board_lock);
628
David Brownell8ae12a02006-01-08 13:34:19 -0800629 status = 0;
Anatolij Gustschin12b15e82010-07-27 22:35:58 +0200630
631 /* Register devices from the device tree */
632 of_register_spi_devices(master);
David Brownell8ae12a02006-01-08 13:34:19 -0800633done:
634 return status;
635}
636EXPORT_SYMBOL_GPL(spi_register_master);
637
638
David Lamparter34860082010-08-30 23:54:17 +0200639static int __unregister(struct device *dev, void *null)
David Brownell8ae12a02006-01-08 13:34:19 -0800640{
David Lamparter34860082010-08-30 23:54:17 +0200641 spi_unregister_device(to_spi_device(dev));
David Brownell8ae12a02006-01-08 13:34:19 -0800642 return 0;
643}
644
645/**
646 * spi_unregister_master - unregister SPI master controller
647 * @master: the master being unregistered
David Brownell33e34dc2007-05-08 00:32:21 -0700648 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800649 *
650 * This call is used only by SPI master controller drivers, which are the
651 * only ones directly touching chip registers.
652 *
653 * This must be called from context that can sleep.
654 */
655void spi_unregister_master(struct spi_master *master)
656{
Jeff Garzik89fc9a12006-12-06 20:35:35 -0800657 int dummy;
658
Feng Tang2b9603a2010-08-02 15:52:15 +0800659 mutex_lock(&board_lock);
660 list_del(&master->list);
661 mutex_unlock(&board_lock);
662
Sebastian Andrzej Siewior97dbf372010-12-21 17:24:31 -0800663 dummy = device_for_each_child(&master->dev, NULL, __unregister);
Tony Jones49dce682007-10-16 01:27:48 -0700664 device_unregister(&master->dev);
David Brownell8ae12a02006-01-08 13:34:19 -0800665}
666EXPORT_SYMBOL_GPL(spi_unregister_master);
667
Dave Young5ed2c832008-01-22 15:14:18 +0800668static int __spi_master_match(struct device *dev, void *data)
669{
670 struct spi_master *m;
671 u16 *bus_num = data;
672
673 m = container_of(dev, struct spi_master, dev);
674 return m->bus_num == *bus_num;
675}
676
David Brownell8ae12a02006-01-08 13:34:19 -0800677/**
678 * spi_busnum_to_master - look up master associated with bus_num
679 * @bus_num: the master's bus number
David Brownell33e34dc2007-05-08 00:32:21 -0700680 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800681 *
682 * This call may be used with devices that are registered after
683 * arch init time. It returns a refcounted pointer to the relevant
684 * spi_master (which the caller must release), or NULL if there is
685 * no such master registered.
686 */
687struct spi_master *spi_busnum_to_master(u16 bus_num)
688{
Tony Jones49dce682007-10-16 01:27:48 -0700689 struct device *dev;
Atsushi Nemoto1e9a51d2007-01-26 00:56:54 -0800690 struct spi_master *master = NULL;
David Brownell8ae12a02006-01-08 13:34:19 -0800691
Greg Kroah-Hartman695794a2008-05-22 17:21:08 -0400692 dev = class_find_device(&spi_master_class, NULL, &bus_num,
Dave Young5ed2c832008-01-22 15:14:18 +0800693 __spi_master_match);
694 if (dev)
695 master = container_of(dev, struct spi_master, dev);
696 /* reference got in class_find_device */
Atsushi Nemoto1e9a51d2007-01-26 00:56:54 -0800697 return master;
David Brownell8ae12a02006-01-08 13:34:19 -0800698}
699EXPORT_SYMBOL_GPL(spi_busnum_to_master);
700
701
702/*-------------------------------------------------------------------------*/
703
David Brownell7d077192009-06-17 16:26:03 -0700704/* Core methods for SPI master protocol drivers. Some of the
705 * other core methods are currently defined as inline functions.
706 */
707
708/**
709 * spi_setup - setup SPI mode and clock rate
710 * @spi: the device whose settings are being modified
711 * Context: can sleep, and no requests are queued to the device
712 *
713 * SPI protocol drivers may need to update the transfer mode if the
714 * device doesn't work with its default. They may likewise need
715 * to update clock rates or word sizes from initial values. This function
716 * changes those settings, and must be called from a context that can sleep.
717 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
718 * effect the next time the device is selected and data is transferred to
719 * or from it. When this function returns, the spi device is deselected.
720 *
721 * Note that this call will fail if the protocol driver specifies an option
722 * that the underlying controller or its driver does not support. For
723 * example, not all hardware supports wire transfers using nine bit words,
724 * LSB-first wire encoding, or active-high chipselects.
725 */
726int spi_setup(struct spi_device *spi)
727{
David Brownelle7db06b2009-06-17 16:26:04 -0700728 unsigned bad_bits;
David Brownell7d077192009-06-17 16:26:03 -0700729 int status;
730
David Brownelle7db06b2009-06-17 16:26:04 -0700731 /* help drivers fail *cleanly* when they need options
732 * that aren't supported with their current master
733 */
734 bad_bits = spi->mode & ~spi->master->mode_bits;
735 if (bad_bits) {
Linus Walleijeb288a12010-10-21 21:06:44 +0200736 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
David Brownelle7db06b2009-06-17 16:26:04 -0700737 bad_bits);
738 return -EINVAL;
739 }
740
David Brownell7d077192009-06-17 16:26:03 -0700741 if (!spi->bits_per_word)
742 spi->bits_per_word = 8;
743
744 status = spi->master->setup(spi);
745
746 dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s"
747 "%u bits/w, %u Hz max --> %d\n",
748 (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
749 (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
750 (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
751 (spi->mode & SPI_3WIRE) ? "3wire, " : "",
752 (spi->mode & SPI_LOOP) ? "loopback, " : "",
753 spi->bits_per_word, spi->max_speed_hz,
754 status);
755
756 return status;
757}
758EXPORT_SYMBOL_GPL(spi_setup);
759
Ernst Schwabcf32b712010-06-28 17:49:29 -0700760static int __spi_async(struct spi_device *spi, struct spi_message *message)
761{
762 struct spi_master *master = spi->master;
763
764 /* Half-duplex links include original MicroWire, and ones with
765 * only one data pin like SPI_3WIRE (switches direction) or where
766 * either MOSI or MISO is missing. They can also be caused by
767 * software limitations.
768 */
769 if ((master->flags & SPI_MASTER_HALF_DUPLEX)
770 || (spi->mode & SPI_3WIRE)) {
771 struct spi_transfer *xfer;
772 unsigned flags = master->flags;
773
774 list_for_each_entry(xfer, &message->transfers, transfer_list) {
775 if (xfer->rx_buf && xfer->tx_buf)
776 return -EINVAL;
777 if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
778 return -EINVAL;
779 if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
780 return -EINVAL;
781 }
782 }
783
784 message->spi = spi;
785 message->status = -EINPROGRESS;
786 return master->transfer(spi, message);
787}
788
David Brownell568d0692009-09-22 16:46:18 -0700789/**
790 * spi_async - asynchronous SPI transfer
791 * @spi: device with which data will be exchanged
792 * @message: describes the data transfers, including completion callback
793 * Context: any (irqs may be blocked, etc)
794 *
795 * This call may be used in_irq and other contexts which can't sleep,
796 * as well as from task contexts which can sleep.
797 *
798 * The completion callback is invoked in a context which can't sleep.
799 * Before that invocation, the value of message->status is undefined.
800 * When the callback is issued, message->status holds either zero (to
801 * indicate complete success) or a negative error code. After that
802 * callback returns, the driver which issued the transfer request may
803 * deallocate the associated memory; it's no longer in use by any SPI
804 * core or controller driver code.
805 *
806 * Note that although all messages to a spi_device are handled in
807 * FIFO order, messages may go to different devices in other orders.
808 * Some device might be higher priority, or have various "hard" access
809 * time requirements, for example.
810 *
811 * On detection of any fault during the transfer, processing of
812 * the entire message is aborted, and the device is deselected.
813 * Until returning from the associated message completion callback,
814 * no other spi_message queued to that device will be processed.
815 * (This rule applies equally to all the synchronous transfer calls,
816 * which are wrappers around this core asynchronous primitive.)
817 */
818int spi_async(struct spi_device *spi, struct spi_message *message)
819{
820 struct spi_master *master = spi->master;
Ernst Schwabcf32b712010-06-28 17:49:29 -0700821 int ret;
822 unsigned long flags;
David Brownell568d0692009-09-22 16:46:18 -0700823
Ernst Schwabcf32b712010-06-28 17:49:29 -0700824 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
David Brownell568d0692009-09-22 16:46:18 -0700825
Ernst Schwabcf32b712010-06-28 17:49:29 -0700826 if (master->bus_lock_flag)
827 ret = -EBUSY;
828 else
829 ret = __spi_async(spi, message);
David Brownell568d0692009-09-22 16:46:18 -0700830
Ernst Schwabcf32b712010-06-28 17:49:29 -0700831 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
832
833 return ret;
David Brownell568d0692009-09-22 16:46:18 -0700834}
835EXPORT_SYMBOL_GPL(spi_async);
836
Ernst Schwabcf32b712010-06-28 17:49:29 -0700837/**
838 * spi_async_locked - version of spi_async with exclusive bus usage
839 * @spi: device with which data will be exchanged
840 * @message: describes the data transfers, including completion callback
841 * Context: any (irqs may be blocked, etc)
842 *
843 * This call may be used in_irq and other contexts which can't sleep,
844 * as well as from task contexts which can sleep.
845 *
846 * The completion callback is invoked in a context which can't sleep.
847 * Before that invocation, the value of message->status is undefined.
848 * When the callback is issued, message->status holds either zero (to
849 * indicate complete success) or a negative error code. After that
850 * callback returns, the driver which issued the transfer request may
851 * deallocate the associated memory; it's no longer in use by any SPI
852 * core or controller driver code.
853 *
854 * Note that although all messages to a spi_device are handled in
855 * FIFO order, messages may go to different devices in other orders.
856 * Some device might be higher priority, or have various "hard" access
857 * time requirements, for example.
858 *
859 * On detection of any fault during the transfer, processing of
860 * the entire message is aborted, and the device is deselected.
861 * Until returning from the associated message completion callback,
862 * no other spi_message queued to that device will be processed.
863 * (This rule applies equally to all the synchronous transfer calls,
864 * which are wrappers around this core asynchronous primitive.)
865 */
866int spi_async_locked(struct spi_device *spi, struct spi_message *message)
867{
868 struct spi_master *master = spi->master;
869 int ret;
870 unsigned long flags;
871
872 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
873
874 ret = __spi_async(spi, message);
875
876 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
877
878 return ret;
879
880}
881EXPORT_SYMBOL_GPL(spi_async_locked);
882
David Brownell7d077192009-06-17 16:26:03 -0700883
884/*-------------------------------------------------------------------------*/
885
886/* Utility methods for SPI master protocol drivers, layered on
887 * top of the core. Some other utility methods are defined as
888 * inline functions.
889 */
890
Andrew Morton5d870c82006-01-11 11:23:49 -0800891static void spi_complete(void *arg)
892{
893 complete(arg);
894}
895
Ernst Schwabcf32b712010-06-28 17:49:29 -0700896static int __spi_sync(struct spi_device *spi, struct spi_message *message,
897 int bus_locked)
898{
899 DECLARE_COMPLETION_ONSTACK(done);
900 int status;
901 struct spi_master *master = spi->master;
902
903 message->complete = spi_complete;
904 message->context = &done;
905
906 if (!bus_locked)
907 mutex_lock(&master->bus_lock_mutex);
908
909 status = spi_async_locked(spi, message);
910
911 if (!bus_locked)
912 mutex_unlock(&master->bus_lock_mutex);
913
914 if (status == 0) {
915 wait_for_completion(&done);
916 status = message->status;
917 }
918 message->context = NULL;
919 return status;
920}
921
David Brownell8ae12a02006-01-08 13:34:19 -0800922/**
923 * spi_sync - blocking/synchronous SPI data transfers
924 * @spi: device with which data will be exchanged
925 * @message: describes the data transfers
David Brownell33e34dc2007-05-08 00:32:21 -0700926 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800927 *
928 * This call may only be used from a context that may sleep. The sleep
929 * is non-interruptible, and has no timeout. Low-overhead controller
930 * drivers may DMA directly into and out of the message buffers.
931 *
932 * Note that the SPI device's chip select is active during the message,
933 * and then is normally disabled between messages. Drivers for some
934 * frequently-used devices may want to minimize costs of selecting a chip,
935 * by leaving it selected in anticipation that the next message will go
936 * to the same chip. (That may increase power usage.)
937 *
David Brownell0c868462006-01-08 13:34:25 -0800938 * Also, the caller is guaranteeing that the memory associated with the
939 * message will not be freed before this call returns.
940 *
Marc Pignat9b938b72007-12-04 23:45:10 -0800941 * It returns zero on success, else a negative error code.
David Brownell8ae12a02006-01-08 13:34:19 -0800942 */
943int spi_sync(struct spi_device *spi, struct spi_message *message)
944{
Ernst Schwabcf32b712010-06-28 17:49:29 -0700945 return __spi_sync(spi, message, 0);
David Brownell8ae12a02006-01-08 13:34:19 -0800946}
947EXPORT_SYMBOL_GPL(spi_sync);
948
Ernst Schwabcf32b712010-06-28 17:49:29 -0700949/**
950 * spi_sync_locked - version of spi_sync with exclusive bus usage
951 * @spi: device with which data will be exchanged
952 * @message: describes the data transfers
953 * Context: can sleep
954 *
955 * This call may only be used from a context that may sleep. The sleep
956 * is non-interruptible, and has no timeout. Low-overhead controller
957 * drivers may DMA directly into and out of the message buffers.
958 *
959 * This call should be used by drivers that require exclusive access to the
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300960 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
Ernst Schwabcf32b712010-06-28 17:49:29 -0700961 * be released by a spi_bus_unlock call when the exclusive access is over.
962 *
963 * It returns zero on success, else a negative error code.
964 */
965int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
966{
967 return __spi_sync(spi, message, 1);
968}
969EXPORT_SYMBOL_GPL(spi_sync_locked);
970
971/**
972 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
973 * @master: SPI bus master that should be locked for exclusive bus access
974 * Context: can sleep
975 *
976 * This call may only be used from a context that may sleep. The sleep
977 * is non-interruptible, and has no timeout.
978 *
979 * This call should be used by drivers that require exclusive access to the
980 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
981 * exclusive access is over. Data transfer must be done by spi_sync_locked
982 * and spi_async_locked calls when the SPI bus lock is held.
983 *
984 * It returns zero on success, else a negative error code.
985 */
986int spi_bus_lock(struct spi_master *master)
987{
988 unsigned long flags;
989
990 mutex_lock(&master->bus_lock_mutex);
991
992 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
993 master->bus_lock_flag = 1;
994 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
995
996 /* mutex remains locked until spi_bus_unlock is called */
997
998 return 0;
999}
1000EXPORT_SYMBOL_GPL(spi_bus_lock);
1001
1002/**
1003 * spi_bus_unlock - release the lock for exclusive SPI bus usage
1004 * @master: SPI bus master that was locked for exclusive bus access
1005 * Context: can sleep
1006 *
1007 * This call may only be used from a context that may sleep. The sleep
1008 * is non-interruptible, and has no timeout.
1009 *
1010 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
1011 * call.
1012 *
1013 * It returns zero on success, else a negative error code.
1014 */
1015int spi_bus_unlock(struct spi_master *master)
1016{
1017 master->bus_lock_flag = 0;
1018
1019 mutex_unlock(&master->bus_lock_mutex);
1020
1021 return 0;
1022}
1023EXPORT_SYMBOL_GPL(spi_bus_unlock);
1024
David Brownella9948b62006-04-02 10:37:40 -08001025/* portable code must never pass more than 32 bytes */
1026#define SPI_BUFSIZ max(32,SMP_CACHE_BYTES)
David Brownell8ae12a02006-01-08 13:34:19 -08001027
1028static u8 *buf;
1029
1030/**
1031 * spi_write_then_read - SPI synchronous write followed by read
1032 * @spi: device with which data will be exchanged
1033 * @txbuf: data to be written (need not be dma-safe)
1034 * @n_tx: size of txbuf, in bytes
Jiri Pirko27570492009-06-17 16:26:06 -07001035 * @rxbuf: buffer into which data will be read (need not be dma-safe)
1036 * @n_rx: size of rxbuf, in bytes
David Brownell33e34dc2007-05-08 00:32:21 -07001037 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -08001038 *
1039 * This performs a half duplex MicroWire style transaction with the
1040 * device, sending txbuf and then reading rxbuf. The return value
1041 * is zero for success, else a negative errno status code.
David Brownellb8852442006-01-08 13:34:23 -08001042 * This call may only be used from a context that may sleep.
David Brownell8ae12a02006-01-08 13:34:19 -08001043 *
David Brownell0c868462006-01-08 13:34:25 -08001044 * Parameters to this routine are always copied using a small buffer;
David Brownell33e34dc2007-05-08 00:32:21 -07001045 * portable code should never use this for more than 32 bytes.
1046 * Performance-sensitive or bulk transfer code should instead use
David Brownell0c868462006-01-08 13:34:25 -08001047 * spi_{async,sync}() calls with dma-safe buffers.
David Brownell8ae12a02006-01-08 13:34:19 -08001048 */
1049int spi_write_then_read(struct spi_device *spi,
1050 const u8 *txbuf, unsigned n_tx,
1051 u8 *rxbuf, unsigned n_rx)
1052{
David Brownell068f4072007-12-04 23:45:09 -08001053 static DEFINE_MUTEX(lock);
David Brownell8ae12a02006-01-08 13:34:19 -08001054
1055 int status;
1056 struct spi_message message;
David Brownellbdff5492009-04-13 14:39:57 -07001057 struct spi_transfer x[2];
David Brownell8ae12a02006-01-08 13:34:19 -08001058 u8 *local_buf;
1059
1060 /* Use preallocated DMA-safe buffer. We can't avoid copying here,
1061 * (as a pure convenience thing), but we can keep heap costs
1062 * out of the hot path ...
1063 */
1064 if ((n_tx + n_rx) > SPI_BUFSIZ)
1065 return -EINVAL;
1066
Vitaly Wool8275c642006-01-08 13:34:28 -08001067 spi_message_init(&message);
David Brownellbdff5492009-04-13 14:39:57 -07001068 memset(x, 0, sizeof x);
1069 if (n_tx) {
1070 x[0].len = n_tx;
1071 spi_message_add_tail(&x[0], &message);
1072 }
1073 if (n_rx) {
1074 x[1].len = n_rx;
1075 spi_message_add_tail(&x[1], &message);
1076 }
Vitaly Wool8275c642006-01-08 13:34:28 -08001077
David Brownell8ae12a02006-01-08 13:34:19 -08001078 /* ... unless someone else is using the pre-allocated buffer */
David Brownell068f4072007-12-04 23:45:09 -08001079 if (!mutex_trylock(&lock)) {
David Brownell8ae12a02006-01-08 13:34:19 -08001080 local_buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
1081 if (!local_buf)
1082 return -ENOMEM;
1083 } else
1084 local_buf = buf;
1085
David Brownell8ae12a02006-01-08 13:34:19 -08001086 memcpy(local_buf, txbuf, n_tx);
David Brownellbdff5492009-04-13 14:39:57 -07001087 x[0].tx_buf = local_buf;
1088 x[1].rx_buf = local_buf + n_tx;
David Brownell8ae12a02006-01-08 13:34:19 -08001089
1090 /* do the i/o */
David Brownell8ae12a02006-01-08 13:34:19 -08001091 status = spi_sync(spi, &message);
Marc Pignat9b938b72007-12-04 23:45:10 -08001092 if (status == 0)
David Brownellbdff5492009-04-13 14:39:57 -07001093 memcpy(rxbuf, x[1].rx_buf, n_rx);
David Brownell8ae12a02006-01-08 13:34:19 -08001094
David Brownellbdff5492009-04-13 14:39:57 -07001095 if (x[0].tx_buf == buf)
David Brownell068f4072007-12-04 23:45:09 -08001096 mutex_unlock(&lock);
David Brownell8ae12a02006-01-08 13:34:19 -08001097 else
1098 kfree(local_buf);
1099
1100 return status;
1101}
1102EXPORT_SYMBOL_GPL(spi_write_then_read);
1103
1104/*-------------------------------------------------------------------------*/
1105
1106static int __init spi_init(void)
1107{
David Brownellb8852442006-01-08 13:34:23 -08001108 int status;
David Brownell8ae12a02006-01-08 13:34:19 -08001109
Christoph Lametere94b1762006-12-06 20:33:17 -08001110 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
David Brownellb8852442006-01-08 13:34:23 -08001111 if (!buf) {
1112 status = -ENOMEM;
1113 goto err0;
1114 }
1115
1116 status = bus_register(&spi_bus_type);
1117 if (status < 0)
1118 goto err1;
1119
1120 status = class_register(&spi_master_class);
1121 if (status < 0)
1122 goto err2;
David Brownell8ae12a02006-01-08 13:34:19 -08001123 return 0;
David Brownellb8852442006-01-08 13:34:23 -08001124
1125err2:
1126 bus_unregister(&spi_bus_type);
1127err1:
1128 kfree(buf);
1129 buf = NULL;
1130err0:
1131 return status;
David Brownell8ae12a02006-01-08 13:34:19 -08001132}
David Brownellb8852442006-01-08 13:34:23 -08001133
David Brownell8ae12a02006-01-08 13:34:19 -08001134/* board_info is normally registered in arch_initcall(),
1135 * but even essential drivers wait till later
David Brownellb8852442006-01-08 13:34:23 -08001136 *
1137 * REVISIT only boardinfo really needs static linking. the rest (device and
1138 * driver registration) _could_ be dynamically linked (modular) ... costs
1139 * include needing to have boardinfo data structures be much more public.
David Brownell8ae12a02006-01-08 13:34:19 -08001140 */
David Brownell673c0c02008-10-15 22:02:46 -07001141postcore_initcall(spi_init);
David Brownell8ae12a02006-01-08 13:34:19 -08001142