blob: 77eae99af11ce7ee1541816f3e8c99b352b7a241 [file] [log] [blame]
David Brownell8ae12a02006-01-08 13:34:19 -08001/*
Grant Likelyca632f52011-06-06 01:16:30 -06002 * SPI init/core code
David Brownell8ae12a02006-01-08 13:34:19 -08003 *
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>
Paul Gortmaker025ed132011-07-10 12:57:55 -040032#include <linux/export.h>
David Brownell8ae12a02006-01-08 13:34:19 -080033
David Brownell8ae12a02006-01-08 13:34:19 -080034static void spidev_release(struct device *dev)
35{
Hans-Peter Nilsson0ffa0282007-02-12 00:52:45 -080036 struct spi_device *spi = to_spi_device(dev);
David Brownell8ae12a02006-01-08 13:34:19 -080037
38 /* spi masters may cleanup for released devices */
39 if (spi->master->cleanup)
40 spi->master->cleanup(spi);
41
David Brownell0c868462006-01-08 13:34:25 -080042 spi_master_put(spi->master);
Roman Tereshonkov07a389f2010-04-12 09:56:35 +000043 kfree(spi);
David Brownell8ae12a02006-01-08 13:34:19 -080044}
45
46static ssize_t
47modalias_show(struct device *dev, struct device_attribute *a, char *buf)
48{
49 const struct spi_device *spi = to_spi_device(dev);
50
Kay Sievers35f74fc2009-01-06 10:44:37 -080051 return sprintf(buf, "%s\n", spi->modalias);
David Brownell8ae12a02006-01-08 13:34:19 -080052}
53
54static struct device_attribute spi_dev_attrs[] = {
55 __ATTR_RO(modalias),
56 __ATTR_NULL,
57};
58
59/* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
60 * and the sysfs version makes coldplug work too.
61 */
62
Anton Vorontsov75368bf2009-09-22 16:46:04 -070063static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
64 const struct spi_device *sdev)
65{
66 while (id->name[0]) {
67 if (!strcmp(sdev->modalias, id->name))
68 return id;
69 id++;
70 }
71 return NULL;
72}
73
74const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
75{
76 const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
77
78 return spi_match_id(sdrv->id_table, sdev);
79}
80EXPORT_SYMBOL_GPL(spi_get_device_id);
81
David Brownell8ae12a02006-01-08 13:34:19 -080082static int spi_match_device(struct device *dev, struct device_driver *drv)
83{
84 const struct spi_device *spi = to_spi_device(dev);
Anton Vorontsov75368bf2009-09-22 16:46:04 -070085 const struct spi_driver *sdrv = to_spi_driver(drv);
86
Sinan Akman2b7a32f2010-10-02 21:28:29 -060087 /* Attempt an OF style match */
88 if (of_driver_match_device(dev, drv))
89 return 1;
90
Anton Vorontsov75368bf2009-09-22 16:46:04 -070091 if (sdrv->id_table)
92 return !!spi_match_id(sdrv->id_table, spi);
David Brownell8ae12a02006-01-08 13:34:19 -080093
Kay Sievers35f74fc2009-01-06 10:44:37 -080094 return strcmp(spi->modalias, drv->name) == 0;
David Brownell8ae12a02006-01-08 13:34:19 -080095}
96
Kay Sievers7eff2e72007-08-14 15:15:12 +020097static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
David Brownell8ae12a02006-01-08 13:34:19 -080098{
99 const struct spi_device *spi = to_spi_device(dev);
100
Anton Vorontsove0626e32009-09-22 16:46:08 -0700101 add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
David Brownell8ae12a02006-01-08 13:34:19 -0800102 return 0;
103}
104
Mark Brown3ae22e82010-12-25 15:32:27 +0100105#ifdef CONFIG_PM_SLEEP
106static int spi_legacy_suspend(struct device *dev, pm_message_t message)
David Brownell8ae12a02006-01-08 13:34:19 -0800107{
David Brownell3c724262008-02-06 01:38:10 -0800108 int value = 0;
David Brownellb8852442006-01-08 13:34:23 -0800109 struct spi_driver *drv = to_spi_driver(dev->driver);
David Brownell8ae12a02006-01-08 13:34:19 -0800110
David Brownell8ae12a02006-01-08 13:34:19 -0800111 /* suspend will stop irqs and dma; no more i/o */
David Brownell3c724262008-02-06 01:38:10 -0800112 if (drv) {
113 if (drv->suspend)
114 value = drv->suspend(to_spi_device(dev), message);
115 else
116 dev_dbg(dev, "... can't suspend\n");
117 }
David Brownell8ae12a02006-01-08 13:34:19 -0800118 return value;
119}
120
Mark Brown3ae22e82010-12-25 15:32:27 +0100121static int spi_legacy_resume(struct device *dev)
David Brownell8ae12a02006-01-08 13:34:19 -0800122{
David Brownell3c724262008-02-06 01:38:10 -0800123 int value = 0;
David Brownellb8852442006-01-08 13:34:23 -0800124 struct spi_driver *drv = to_spi_driver(dev->driver);
David Brownell8ae12a02006-01-08 13:34:19 -0800125
David Brownell8ae12a02006-01-08 13:34:19 -0800126 /* resume may restart the i/o queue */
David Brownell3c724262008-02-06 01:38:10 -0800127 if (drv) {
128 if (drv->resume)
129 value = drv->resume(to_spi_device(dev));
130 else
131 dev_dbg(dev, "... can't resume\n");
132 }
David Brownell8ae12a02006-01-08 13:34:19 -0800133 return value;
134}
135
Mark Brown3ae22e82010-12-25 15:32:27 +0100136static int spi_pm_suspend(struct device *dev)
137{
138 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
139
140 if (pm)
141 return pm_generic_suspend(dev);
142 else
143 return spi_legacy_suspend(dev, PMSG_SUSPEND);
144}
145
146static int spi_pm_resume(struct device *dev)
147{
148 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
149
150 if (pm)
151 return pm_generic_resume(dev);
152 else
153 return spi_legacy_resume(dev);
154}
155
156static int spi_pm_freeze(struct device *dev)
157{
158 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
159
160 if (pm)
161 return pm_generic_freeze(dev);
162 else
163 return spi_legacy_suspend(dev, PMSG_FREEZE);
164}
165
166static int spi_pm_thaw(struct device *dev)
167{
168 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
169
170 if (pm)
171 return pm_generic_thaw(dev);
172 else
173 return spi_legacy_resume(dev);
174}
175
176static int spi_pm_poweroff(struct device *dev)
177{
178 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
179
180 if (pm)
181 return pm_generic_poweroff(dev);
182 else
183 return spi_legacy_suspend(dev, PMSG_HIBERNATE);
184}
185
186static int spi_pm_restore(struct device *dev)
187{
188 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
189
190 if (pm)
191 return pm_generic_restore(dev);
192 else
193 return spi_legacy_resume(dev);
194}
David Brownell8ae12a02006-01-08 13:34:19 -0800195#else
Mark Brown3ae22e82010-12-25 15:32:27 +0100196#define spi_pm_suspend NULL
197#define spi_pm_resume NULL
198#define spi_pm_freeze NULL
199#define spi_pm_thaw NULL
200#define spi_pm_poweroff NULL
201#define spi_pm_restore NULL
David Brownell8ae12a02006-01-08 13:34:19 -0800202#endif
203
Mark Brown3ae22e82010-12-25 15:32:27 +0100204static const struct dev_pm_ops spi_pm = {
205 .suspend = spi_pm_suspend,
206 .resume = spi_pm_resume,
207 .freeze = spi_pm_freeze,
208 .thaw = spi_pm_thaw,
209 .poweroff = spi_pm_poweroff,
210 .restore = spi_pm_restore,
211 SET_RUNTIME_PM_OPS(
212 pm_generic_runtime_suspend,
213 pm_generic_runtime_resume,
214 pm_generic_runtime_idle
215 )
216};
217
David Brownell8ae12a02006-01-08 13:34:19 -0800218struct bus_type spi_bus_type = {
219 .name = "spi",
220 .dev_attrs = spi_dev_attrs,
221 .match = spi_match_device,
222 .uevent = spi_uevent,
Mark Brown3ae22e82010-12-25 15:32:27 +0100223 .pm = &spi_pm,
David Brownell8ae12a02006-01-08 13:34:19 -0800224};
225EXPORT_SYMBOL_GPL(spi_bus_type);
226
David Brownellb8852442006-01-08 13:34:23 -0800227
228static int spi_drv_probe(struct device *dev)
229{
230 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
231
232 return sdrv->probe(to_spi_device(dev));
233}
234
235static int spi_drv_remove(struct device *dev)
236{
237 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
238
239 return sdrv->remove(to_spi_device(dev));
240}
241
242static void spi_drv_shutdown(struct device *dev)
243{
244 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
245
246 sdrv->shutdown(to_spi_device(dev));
247}
248
David Brownell33e34dc2007-05-08 00:32:21 -0700249/**
250 * spi_register_driver - register a SPI driver
251 * @sdrv: the driver to register
252 * Context: can sleep
253 */
David Brownellb8852442006-01-08 13:34:23 -0800254int spi_register_driver(struct spi_driver *sdrv)
255{
256 sdrv->driver.bus = &spi_bus_type;
257 if (sdrv->probe)
258 sdrv->driver.probe = spi_drv_probe;
259 if (sdrv->remove)
260 sdrv->driver.remove = spi_drv_remove;
261 if (sdrv->shutdown)
262 sdrv->driver.shutdown = spi_drv_shutdown;
263 return driver_register(&sdrv->driver);
264}
265EXPORT_SYMBOL_GPL(spi_register_driver);
266
David Brownell8ae12a02006-01-08 13:34:19 -0800267/*-------------------------------------------------------------------------*/
268
269/* SPI devices should normally not be created by SPI device drivers; that
270 * would make them board-specific. Similarly with SPI master drivers.
271 * Device registration normally goes into like arch/.../mach.../board-YYY.c
272 * with other readonly (flashable) information about mainboard devices.
273 */
274
275struct boardinfo {
276 struct list_head list;
Feng Tang2b9603a2010-08-02 15:52:15 +0800277 struct spi_board_info board_info;
David Brownell8ae12a02006-01-08 13:34:19 -0800278};
279
280static LIST_HEAD(board_list);
Feng Tang2b9603a2010-08-02 15:52:15 +0800281static LIST_HEAD(spi_master_list);
282
283/*
284 * Used to protect add/del opertion for board_info list and
285 * spi_master list, and their matching process
286 */
Matthias Kaehlcke94040822007-07-17 04:04:16 -0700287static DEFINE_MUTEX(board_lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800288
Grant Likelydc87c982008-05-15 16:50:22 -0600289/**
290 * spi_alloc_device - Allocate a new SPI device
291 * @master: Controller to which device is connected
292 * Context: can sleep
293 *
294 * Allows a driver to allocate and initialize a spi_device without
295 * registering it immediately. This allows a driver to directly
296 * fill the spi_device with device parameters before calling
297 * spi_add_device() on it.
298 *
299 * Caller is responsible to call spi_add_device() on the returned
300 * spi_device structure to add it to the SPI master. If the caller
301 * needs to discard the spi_device without adding it, then it should
302 * call spi_dev_put() on it.
303 *
304 * Returns a pointer to the new device, or NULL.
305 */
306struct spi_device *spi_alloc_device(struct spi_master *master)
307{
308 struct spi_device *spi;
309 struct device *dev = master->dev.parent;
310
311 if (!spi_master_get(master))
312 return NULL;
313
314 spi = kzalloc(sizeof *spi, GFP_KERNEL);
315 if (!spi) {
316 dev_err(dev, "cannot alloc spi_device\n");
317 spi_master_put(master);
318 return NULL;
319 }
320
321 spi->master = master;
322 spi->dev.parent = dev;
323 spi->dev.bus = &spi_bus_type;
324 spi->dev.release = spidev_release;
325 device_initialize(&spi->dev);
326 return spi;
327}
328EXPORT_SYMBOL_GPL(spi_alloc_device);
329
330/**
331 * spi_add_device - Add spi_device allocated with spi_alloc_device
332 * @spi: spi_device to register
333 *
334 * Companion function to spi_alloc_device. Devices allocated with
335 * spi_alloc_device can be added onto the spi bus with this function.
336 *
David Brownelle48880e2008-08-15 00:40:44 -0700337 * Returns 0 on success; negative errno on failure
Grant Likelydc87c982008-05-15 16:50:22 -0600338 */
339int spi_add_device(struct spi_device *spi)
340{
David Brownelle48880e2008-08-15 00:40:44 -0700341 static DEFINE_MUTEX(spi_add_lock);
Grant Likelydc87c982008-05-15 16:50:22 -0600342 struct device *dev = spi->master->dev.parent;
Roman Tereshonkov8ec130a2010-04-16 09:52:59 +0000343 struct device *d;
Grant Likelydc87c982008-05-15 16:50:22 -0600344 int status;
345
346 /* Chipselects are numbered 0..max; validate. */
347 if (spi->chip_select >= spi->master->num_chipselect) {
348 dev_err(dev, "cs%d >= max %d\n",
349 spi->chip_select,
350 spi->master->num_chipselect);
351 return -EINVAL;
352 }
353
354 /* Set the bus ID string */
Kay Sievers35f74fc2009-01-06 10:44:37 -0800355 dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
Grant Likelydc87c982008-05-15 16:50:22 -0600356 spi->chip_select);
357
David Brownelle48880e2008-08-15 00:40:44 -0700358
359 /* We need to make sure there's no other device with this
360 * chipselect **BEFORE** we call setup(), else we'll trash
361 * its configuration. Lock against concurrent add() calls.
362 */
363 mutex_lock(&spi_add_lock);
364
Roman Tereshonkov8ec130a2010-04-16 09:52:59 +0000365 d = bus_find_device_by_name(&spi_bus_type, NULL, dev_name(&spi->dev));
366 if (d != NULL) {
David Brownelle48880e2008-08-15 00:40:44 -0700367 dev_err(dev, "chipselect %d already in use\n",
368 spi->chip_select);
Roman Tereshonkov8ec130a2010-04-16 09:52:59 +0000369 put_device(d);
David Brownelle48880e2008-08-15 00:40:44 -0700370 status = -EBUSY;
371 goto done;
372 }
373
374 /* Drivers may modify this initial i/o setup, but will
375 * normally rely on the device being setup. Devices
376 * using SPI_CS_HIGH can't coexist well otherwise...
377 */
David Brownell7d077192009-06-17 16:26:03 -0700378 status = spi_setup(spi);
Grant Likelydc87c982008-05-15 16:50:22 -0600379 if (status < 0) {
Linus Walleijeb288a12010-10-21 21:06:44 +0200380 dev_err(dev, "can't setup %s, status %d\n",
381 dev_name(&spi->dev), status);
David Brownelle48880e2008-08-15 00:40:44 -0700382 goto done;
Grant Likelydc87c982008-05-15 16:50:22 -0600383 }
384
David Brownelle48880e2008-08-15 00:40:44 -0700385 /* Device may be bound to an active driver when this returns */
Grant Likelydc87c982008-05-15 16:50:22 -0600386 status = device_add(&spi->dev);
David Brownelle48880e2008-08-15 00:40:44 -0700387 if (status < 0)
Linus Walleijeb288a12010-10-21 21:06:44 +0200388 dev_err(dev, "can't add %s, status %d\n",
389 dev_name(&spi->dev), status);
David Brownelle48880e2008-08-15 00:40:44 -0700390 else
Kay Sievers35f74fc2009-01-06 10:44:37 -0800391 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
Grant Likelydc87c982008-05-15 16:50:22 -0600392
David Brownelle48880e2008-08-15 00:40:44 -0700393done:
394 mutex_unlock(&spi_add_lock);
395 return status;
Grant Likelydc87c982008-05-15 16:50:22 -0600396}
397EXPORT_SYMBOL_GPL(spi_add_device);
David Brownell8ae12a02006-01-08 13:34:19 -0800398
David Brownell33e34dc2007-05-08 00:32:21 -0700399/**
400 * spi_new_device - instantiate one new SPI device
401 * @master: Controller to which device is connected
402 * @chip: Describes the SPI device
403 * Context: can sleep
404 *
405 * On typical mainboards, this is purely internal; and it's not needed
David Brownell8ae12a02006-01-08 13:34:19 -0800406 * after board init creates the hard-wired devices. Some development
407 * platforms may not be able to use spi_register_board_info though, and
408 * this is exported so that for example a USB or parport based adapter
409 * driver could add devices (which it would learn about out-of-band).
David Brownell082c8cb2007-07-31 00:39:45 -0700410 *
411 * Returns the new device, or NULL.
David Brownell8ae12a02006-01-08 13:34:19 -0800412 */
Adrian Bunke9d5a462007-03-26 21:32:23 -0800413struct spi_device *spi_new_device(struct spi_master *master,
414 struct spi_board_info *chip)
David Brownell8ae12a02006-01-08 13:34:19 -0800415{
416 struct spi_device *proxy;
David Brownell8ae12a02006-01-08 13:34:19 -0800417 int status;
418
David Brownell082c8cb2007-07-31 00:39:45 -0700419 /* NOTE: caller did any chip->bus_num checks necessary.
420 *
421 * Also, unless we change the return value convention to use
422 * error-or-pointer (not NULL-or-pointer), troubleshootability
423 * suggests syslogged diagnostics are best here (ugh).
424 */
425
Grant Likelydc87c982008-05-15 16:50:22 -0600426 proxy = spi_alloc_device(master);
427 if (!proxy)
David Brownell8ae12a02006-01-08 13:34:19 -0800428 return NULL;
429
Grant Likely102eb972008-07-23 21:29:55 -0700430 WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
431
David Brownell8ae12a02006-01-08 13:34:19 -0800432 proxy->chip_select = chip->chip_select;
433 proxy->max_speed_hz = chip->max_speed_hz;
David Brownell980a01c2006-06-28 07:47:15 -0700434 proxy->mode = chip->mode;
David Brownell8ae12a02006-01-08 13:34:19 -0800435 proxy->irq = chip->irq;
Grant Likely102eb972008-07-23 21:29:55 -0700436 strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
David Brownell8ae12a02006-01-08 13:34:19 -0800437 proxy->dev.platform_data = (void *) chip->platform_data;
438 proxy->controller_data = chip->controller_data;
439 proxy->controller_state = NULL;
David Brownell8ae12a02006-01-08 13:34:19 -0800440
Grant Likelydc87c982008-05-15 16:50:22 -0600441 status = spi_add_device(proxy);
David Brownell8ae12a02006-01-08 13:34:19 -0800442 if (status < 0) {
Grant Likelydc87c982008-05-15 16:50:22 -0600443 spi_dev_put(proxy);
444 return NULL;
David Brownell8ae12a02006-01-08 13:34:19 -0800445 }
446
David Brownell8ae12a02006-01-08 13:34:19 -0800447 return proxy;
448}
449EXPORT_SYMBOL_GPL(spi_new_device);
450
Feng Tang2b9603a2010-08-02 15:52:15 +0800451static void spi_match_master_to_boardinfo(struct spi_master *master,
452 struct spi_board_info *bi)
453{
454 struct spi_device *dev;
455
456 if (master->bus_num != bi->bus_num)
457 return;
458
459 dev = spi_new_device(master, bi);
460 if (!dev)
461 dev_err(master->dev.parent, "can't create new device for %s\n",
462 bi->modalias);
463}
464
David Brownell33e34dc2007-05-08 00:32:21 -0700465/**
466 * spi_register_board_info - register SPI devices for a given board
467 * @info: array of chip descriptors
468 * @n: how many descriptors are provided
469 * Context: can sleep
470 *
David Brownell8ae12a02006-01-08 13:34:19 -0800471 * Board-specific early init code calls this (probably during arch_initcall)
472 * with segments of the SPI device table. Any device nodes are created later,
473 * after the relevant parent SPI controller (bus_num) is defined. We keep
474 * this table of devices forever, so that reloading a controller driver will
475 * not make Linux forget about these hard-wired devices.
476 *
477 * Other code can also call this, e.g. a particular add-on board might provide
478 * SPI devices through its expansion connector, so code initializing that board
479 * would naturally declare its SPI devices.
480 *
481 * The board info passed can safely be __initdata ... but be careful of
482 * any embedded pointers (platform_data, etc), they're copied as-is.
483 */
484int __init
485spi_register_board_info(struct spi_board_info const *info, unsigned n)
486{
Feng Tang2b9603a2010-08-02 15:52:15 +0800487 struct boardinfo *bi;
488 int i;
David Brownell8ae12a02006-01-08 13:34:19 -0800489
Feng Tang2b9603a2010-08-02 15:52:15 +0800490 bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
David Brownell8ae12a02006-01-08 13:34:19 -0800491 if (!bi)
492 return -ENOMEM;
David Brownell8ae12a02006-01-08 13:34:19 -0800493
Feng Tang2b9603a2010-08-02 15:52:15 +0800494 for (i = 0; i < n; i++, bi++, info++) {
495 struct spi_master *master;
David Brownell8ae12a02006-01-08 13:34:19 -0800496
Feng Tang2b9603a2010-08-02 15:52:15 +0800497 memcpy(&bi->board_info, info, sizeof(*info));
498 mutex_lock(&board_lock);
499 list_add_tail(&bi->list, &board_list);
500 list_for_each_entry(master, &spi_master_list, list)
501 spi_match_master_to_boardinfo(master, &bi->board_info);
502 mutex_unlock(&board_lock);
David Brownell8ae12a02006-01-08 13:34:19 -0800503 }
Feng Tang2b9603a2010-08-02 15:52:15 +0800504
505 return 0;
David Brownell8ae12a02006-01-08 13:34:19 -0800506}
507
508/*-------------------------------------------------------------------------*/
509
Tony Jones49dce682007-10-16 01:27:48 -0700510static void spi_master_release(struct device *dev)
David Brownell8ae12a02006-01-08 13:34:19 -0800511{
512 struct spi_master *master;
513
Tony Jones49dce682007-10-16 01:27:48 -0700514 master = container_of(dev, struct spi_master, dev);
David Brownell8ae12a02006-01-08 13:34:19 -0800515 kfree(master);
516}
517
518static struct class spi_master_class = {
519 .name = "spi_master",
520 .owner = THIS_MODULE,
Tony Jones49dce682007-10-16 01:27:48 -0700521 .dev_release = spi_master_release,
David Brownell8ae12a02006-01-08 13:34:19 -0800522};
523
524
525/**
526 * spi_alloc_master - allocate SPI master controller
527 * @dev: the controller, possibly using the platform_bus
David Brownell33e34dc2007-05-08 00:32:21 -0700528 * @size: how much zeroed driver-private data to allocate; the pointer to this
Tony Jones49dce682007-10-16 01:27:48 -0700529 * memory is in the driver_data field of the returned device,
David Brownell0c868462006-01-08 13:34:25 -0800530 * accessible with spi_master_get_devdata().
David Brownell33e34dc2007-05-08 00:32:21 -0700531 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800532 *
533 * This call is used only by SPI master controller drivers, which are the
534 * only ones directly touching chip registers. It's how they allocate
dmitry pervushinba1a0512006-05-20 15:00:14 -0700535 * an spi_master structure, prior to calling spi_register_master().
David Brownell8ae12a02006-01-08 13:34:19 -0800536 *
537 * This must be called from context that can sleep. It returns the SPI
538 * master structure on success, else NULL.
539 *
540 * The caller is responsible for assigning the bus number and initializing
dmitry pervushinba1a0512006-05-20 15:00:14 -0700541 * the master's methods before calling spi_register_master(); and (after errors
David Brownell0c868462006-01-08 13:34:25 -0800542 * adding the device) calling spi_master_put() to prevent a memory leak.
David Brownell8ae12a02006-01-08 13:34:19 -0800543 */
Adrian Bunke9d5a462007-03-26 21:32:23 -0800544struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
David Brownell8ae12a02006-01-08 13:34:19 -0800545{
546 struct spi_master *master;
547
David Brownell0c868462006-01-08 13:34:25 -0800548 if (!dev)
549 return NULL;
550
Christoph Lametere94b1762006-12-06 20:33:17 -0800551 master = kzalloc(size + sizeof *master, GFP_KERNEL);
David Brownell8ae12a02006-01-08 13:34:19 -0800552 if (!master)
553 return NULL;
554
Tony Jones49dce682007-10-16 01:27:48 -0700555 device_initialize(&master->dev);
556 master->dev.class = &spi_master_class;
557 master->dev.parent = get_device(dev);
David Brownell0c868462006-01-08 13:34:25 -0800558 spi_master_set_devdata(master, &master[1]);
David Brownell8ae12a02006-01-08 13:34:19 -0800559
560 return master;
561}
562EXPORT_SYMBOL_GPL(spi_alloc_master);
563
564/**
565 * spi_register_master - register SPI master controller
566 * @master: initialized master, originally from spi_alloc_master()
David Brownell33e34dc2007-05-08 00:32:21 -0700567 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800568 *
569 * SPI master controllers connect to their drivers using some non-SPI bus,
570 * such as the platform bus. The final stage of probe() in that code
571 * includes calling spi_register_master() to hook up to this SPI bus glue.
572 *
573 * SPI controllers use board specific (often SOC specific) bus numbers,
574 * and board-specific addressing for SPI devices combines those numbers
575 * with chip select numbers. Since SPI does not directly support dynamic
576 * device identification, boards need configuration tables telling which
577 * chip is at which address.
578 *
579 * This must be called from context that can sleep. It returns zero on
580 * success, else a negative error code (dropping the master's refcount).
David Brownell0c868462006-01-08 13:34:25 -0800581 * After a successful return, the caller is responsible for calling
582 * spi_unregister_master().
David Brownell8ae12a02006-01-08 13:34:19 -0800583 */
Adrian Bunke9d5a462007-03-26 21:32:23 -0800584int spi_register_master(struct spi_master *master)
David Brownell8ae12a02006-01-08 13:34:19 -0800585{
David Brownelle44a45a2007-06-03 13:50:40 -0700586 static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
Tony Jones49dce682007-10-16 01:27:48 -0700587 struct device *dev = master->dev.parent;
Feng Tang2b9603a2010-08-02 15:52:15 +0800588 struct boardinfo *bi;
David Brownell8ae12a02006-01-08 13:34:19 -0800589 int status = -ENODEV;
590 int dynamic = 0;
591
David Brownell0c868462006-01-08 13:34:25 -0800592 if (!dev)
593 return -ENODEV;
594
David Brownell082c8cb2007-07-31 00:39:45 -0700595 /* even if it's just one always-selected device, there must
596 * be at least one chipselect
597 */
598 if (master->num_chipselect == 0)
599 return -EINVAL;
600
David Brownell8ae12a02006-01-08 13:34:19 -0800601 /* convention: dynamically assigned bus IDs count down from the max */
David Brownella020ed72006-04-03 15:49:04 -0700602 if (master->bus_num < 0) {
David Brownell082c8cb2007-07-31 00:39:45 -0700603 /* FIXME switch to an IDR based scheme, something like
604 * I2C now uses, so we can't run out of "dynamic" IDs
605 */
David Brownell8ae12a02006-01-08 13:34:19 -0800606 master->bus_num = atomic_dec_return(&dyn_bus_id);
David Brownellb8852442006-01-08 13:34:23 -0800607 dynamic = 1;
David Brownell8ae12a02006-01-08 13:34:19 -0800608 }
609
Ernst Schwabcf32b712010-06-28 17:49:29 -0700610 spin_lock_init(&master->bus_lock_spinlock);
611 mutex_init(&master->bus_lock_mutex);
612 master->bus_lock_flag = 0;
613
David Brownell8ae12a02006-01-08 13:34:19 -0800614 /* register the device, then userspace will see it.
615 * registration fails if the bus ID is in use.
616 */
Kay Sievers35f74fc2009-01-06 10:44:37 -0800617 dev_set_name(&master->dev, "spi%u", master->bus_num);
Tony Jones49dce682007-10-16 01:27:48 -0700618 status = device_add(&master->dev);
David Brownellb8852442006-01-08 13:34:23 -0800619 if (status < 0)
David Brownell8ae12a02006-01-08 13:34:19 -0800620 goto done;
Kay Sievers35f74fc2009-01-06 10:44:37 -0800621 dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
David Brownell8ae12a02006-01-08 13:34:19 -0800622 dynamic ? " (dynamic)" : "");
623
Feng Tang2b9603a2010-08-02 15:52:15 +0800624 mutex_lock(&board_lock);
625 list_add_tail(&master->list, &spi_master_list);
626 list_for_each_entry(bi, &board_list, list)
627 spi_match_master_to_boardinfo(master, &bi->board_info);
628 mutex_unlock(&board_lock);
629
David Brownell8ae12a02006-01-08 13:34:19 -0800630 status = 0;
Anatolij Gustschin12b15e82010-07-27 22:35:58 +0200631
632 /* Register devices from the device tree */
633 of_register_spi_devices(master);
David Brownell8ae12a02006-01-08 13:34:19 -0800634done:
635 return status;
636}
637EXPORT_SYMBOL_GPL(spi_register_master);
638
639
David Lamparter34860082010-08-30 23:54:17 +0200640static int __unregister(struct device *dev, void *null)
David Brownell8ae12a02006-01-08 13:34:19 -0800641{
David Lamparter34860082010-08-30 23:54:17 +0200642 spi_unregister_device(to_spi_device(dev));
David Brownell8ae12a02006-01-08 13:34:19 -0800643 return 0;
644}
645
646/**
647 * spi_unregister_master - unregister SPI master controller
648 * @master: the master being unregistered
David Brownell33e34dc2007-05-08 00:32:21 -0700649 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800650 *
651 * This call is used only by SPI master controller drivers, which are the
652 * only ones directly touching chip registers.
653 *
654 * This must be called from context that can sleep.
655 */
656void spi_unregister_master(struct spi_master *master)
657{
Jeff Garzik89fc9a12006-12-06 20:35:35 -0800658 int dummy;
659
Feng Tang2b9603a2010-08-02 15:52:15 +0800660 mutex_lock(&board_lock);
661 list_del(&master->list);
662 mutex_unlock(&board_lock);
663
Sebastian Andrzej Siewior97dbf372010-12-21 17:24:31 -0800664 dummy = device_for_each_child(&master->dev, NULL, __unregister);
Tony Jones49dce682007-10-16 01:27:48 -0700665 device_unregister(&master->dev);
David Brownell8ae12a02006-01-08 13:34:19 -0800666}
667EXPORT_SYMBOL_GPL(spi_unregister_master);
668
Dave Young5ed2c832008-01-22 15:14:18 +0800669static int __spi_master_match(struct device *dev, void *data)
670{
671 struct spi_master *m;
672 u16 *bus_num = data;
673
674 m = container_of(dev, struct spi_master, dev);
675 return m->bus_num == *bus_num;
676}
677
David Brownell8ae12a02006-01-08 13:34:19 -0800678/**
679 * spi_busnum_to_master - look up master associated with bus_num
680 * @bus_num: the master's bus number
David Brownell33e34dc2007-05-08 00:32:21 -0700681 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800682 *
683 * This call may be used with devices that are registered after
684 * arch init time. It returns a refcounted pointer to the relevant
685 * spi_master (which the caller must release), or NULL if there is
686 * no such master registered.
687 */
688struct spi_master *spi_busnum_to_master(u16 bus_num)
689{
Tony Jones49dce682007-10-16 01:27:48 -0700690 struct device *dev;
Atsushi Nemoto1e9a51d2007-01-26 00:56:54 -0800691 struct spi_master *master = NULL;
David Brownell8ae12a02006-01-08 13:34:19 -0800692
Greg Kroah-Hartman695794a2008-05-22 17:21:08 -0400693 dev = class_find_device(&spi_master_class, NULL, &bus_num,
Dave Young5ed2c832008-01-22 15:14:18 +0800694 __spi_master_match);
695 if (dev)
696 master = container_of(dev, struct spi_master, dev);
697 /* reference got in class_find_device */
Atsushi Nemoto1e9a51d2007-01-26 00:56:54 -0800698 return master;
David Brownell8ae12a02006-01-08 13:34:19 -0800699}
700EXPORT_SYMBOL_GPL(spi_busnum_to_master);
701
702
703/*-------------------------------------------------------------------------*/
704
David Brownell7d077192009-06-17 16:26:03 -0700705/* Core methods for SPI master protocol drivers. Some of the
706 * other core methods are currently defined as inline functions.
707 */
708
709/**
710 * spi_setup - setup SPI mode and clock rate
711 * @spi: the device whose settings are being modified
712 * Context: can sleep, and no requests are queued to the device
713 *
714 * SPI protocol drivers may need to update the transfer mode if the
715 * device doesn't work with its default. They may likewise need
716 * to update clock rates or word sizes from initial values. This function
717 * changes those settings, and must be called from a context that can sleep.
718 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
719 * effect the next time the device is selected and data is transferred to
720 * or from it. When this function returns, the spi device is deselected.
721 *
722 * Note that this call will fail if the protocol driver specifies an option
723 * that the underlying controller or its driver does not support. For
724 * example, not all hardware supports wire transfers using nine bit words,
725 * LSB-first wire encoding, or active-high chipselects.
726 */
727int spi_setup(struct spi_device *spi)
728{
David Brownelle7db06b2009-06-17 16:26:04 -0700729 unsigned bad_bits;
David Brownell7d077192009-06-17 16:26:03 -0700730 int status;
731
David Brownelle7db06b2009-06-17 16:26:04 -0700732 /* help drivers fail *cleanly* when they need options
733 * that aren't supported with their current master
734 */
735 bad_bits = spi->mode & ~spi->master->mode_bits;
736 if (bad_bits) {
Linus Walleijeb288a12010-10-21 21:06:44 +0200737 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
David Brownelle7db06b2009-06-17 16:26:04 -0700738 bad_bits);
739 return -EINVAL;
740 }
741
David Brownell7d077192009-06-17 16:26:03 -0700742 if (!spi->bits_per_word)
743 spi->bits_per_word = 8;
744
745 status = spi->master->setup(spi);
746
747 dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s"
748 "%u bits/w, %u Hz max --> %d\n",
749 (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
750 (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
751 (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
752 (spi->mode & SPI_3WIRE) ? "3wire, " : "",
753 (spi->mode & SPI_LOOP) ? "loopback, " : "",
754 spi->bits_per_word, spi->max_speed_hz,
755 status);
756
757 return status;
758}
759EXPORT_SYMBOL_GPL(spi_setup);
760
Ernst Schwabcf32b712010-06-28 17:49:29 -0700761static int __spi_async(struct spi_device *spi, struct spi_message *message)
762{
763 struct spi_master *master = spi->master;
764
765 /* Half-duplex links include original MicroWire, and ones with
766 * only one data pin like SPI_3WIRE (switches direction) or where
767 * either MOSI or MISO is missing. They can also be caused by
768 * software limitations.
769 */
770 if ((master->flags & SPI_MASTER_HALF_DUPLEX)
771 || (spi->mode & SPI_3WIRE)) {
772 struct spi_transfer *xfer;
773 unsigned flags = master->flags;
774
775 list_for_each_entry(xfer, &message->transfers, transfer_list) {
776 if (xfer->rx_buf && xfer->tx_buf)
777 return -EINVAL;
778 if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
779 return -EINVAL;
780 if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
781 return -EINVAL;
782 }
783 }
784
785 message->spi = spi;
786 message->status = -EINPROGRESS;
787 return master->transfer(spi, message);
788}
789
David Brownell568d0692009-09-22 16:46:18 -0700790/**
791 * spi_async - asynchronous SPI transfer
792 * @spi: device with which data will be exchanged
793 * @message: describes the data transfers, including completion callback
794 * Context: any (irqs may be blocked, etc)
795 *
796 * This call may be used in_irq and other contexts which can't sleep,
797 * as well as from task contexts which can sleep.
798 *
799 * The completion callback is invoked in a context which can't sleep.
800 * Before that invocation, the value of message->status is undefined.
801 * When the callback is issued, message->status holds either zero (to
802 * indicate complete success) or a negative error code. After that
803 * callback returns, the driver which issued the transfer request may
804 * deallocate the associated memory; it's no longer in use by any SPI
805 * core or controller driver code.
806 *
807 * Note that although all messages to a spi_device are handled in
808 * FIFO order, messages may go to different devices in other orders.
809 * Some device might be higher priority, or have various "hard" access
810 * time requirements, for example.
811 *
812 * On detection of any fault during the transfer, processing of
813 * the entire message is aborted, and the device is deselected.
814 * Until returning from the associated message completion callback,
815 * no other spi_message queued to that device will be processed.
816 * (This rule applies equally to all the synchronous transfer calls,
817 * which are wrappers around this core asynchronous primitive.)
818 */
819int spi_async(struct spi_device *spi, struct spi_message *message)
820{
821 struct spi_master *master = spi->master;
Ernst Schwabcf32b712010-06-28 17:49:29 -0700822 int ret;
823 unsigned long flags;
David Brownell568d0692009-09-22 16:46:18 -0700824
Ernst Schwabcf32b712010-06-28 17:49:29 -0700825 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
David Brownell568d0692009-09-22 16:46:18 -0700826
Ernst Schwabcf32b712010-06-28 17:49:29 -0700827 if (master->bus_lock_flag)
828 ret = -EBUSY;
829 else
830 ret = __spi_async(spi, message);
David Brownell568d0692009-09-22 16:46:18 -0700831
Ernst Schwabcf32b712010-06-28 17:49:29 -0700832 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
833
834 return ret;
David Brownell568d0692009-09-22 16:46:18 -0700835}
836EXPORT_SYMBOL_GPL(spi_async);
837
Ernst Schwabcf32b712010-06-28 17:49:29 -0700838/**
839 * spi_async_locked - version of spi_async with exclusive bus usage
840 * @spi: device with which data will be exchanged
841 * @message: describes the data transfers, including completion callback
842 * Context: any (irqs may be blocked, etc)
843 *
844 * This call may be used in_irq and other contexts which can't sleep,
845 * as well as from task contexts which can sleep.
846 *
847 * The completion callback is invoked in a context which can't sleep.
848 * Before that invocation, the value of message->status is undefined.
849 * When the callback is issued, message->status holds either zero (to
850 * indicate complete success) or a negative error code. After that
851 * callback returns, the driver which issued the transfer request may
852 * deallocate the associated memory; it's no longer in use by any SPI
853 * core or controller driver code.
854 *
855 * Note that although all messages to a spi_device are handled in
856 * FIFO order, messages may go to different devices in other orders.
857 * Some device might be higher priority, or have various "hard" access
858 * time requirements, for example.
859 *
860 * On detection of any fault during the transfer, processing of
861 * the entire message is aborted, and the device is deselected.
862 * Until returning from the associated message completion callback,
863 * no other spi_message queued to that device will be processed.
864 * (This rule applies equally to all the synchronous transfer calls,
865 * which are wrappers around this core asynchronous primitive.)
866 */
867int spi_async_locked(struct spi_device *spi, struct spi_message *message)
868{
869 struct spi_master *master = spi->master;
870 int ret;
871 unsigned long flags;
872
873 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
874
875 ret = __spi_async(spi, message);
876
877 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
878
879 return ret;
880
881}
882EXPORT_SYMBOL_GPL(spi_async_locked);
883
David Brownell7d077192009-06-17 16:26:03 -0700884
885/*-------------------------------------------------------------------------*/
886
887/* Utility methods for SPI master protocol drivers, layered on
888 * top of the core. Some other utility methods are defined as
889 * inline functions.
890 */
891
Andrew Morton5d870c82006-01-11 11:23:49 -0800892static void spi_complete(void *arg)
893{
894 complete(arg);
895}
896
Ernst Schwabcf32b712010-06-28 17:49:29 -0700897static int __spi_sync(struct spi_device *spi, struct spi_message *message,
898 int bus_locked)
899{
900 DECLARE_COMPLETION_ONSTACK(done);
901 int status;
902 struct spi_master *master = spi->master;
903
904 message->complete = spi_complete;
905 message->context = &done;
906
907 if (!bus_locked)
908 mutex_lock(&master->bus_lock_mutex);
909
910 status = spi_async_locked(spi, message);
911
912 if (!bus_locked)
913 mutex_unlock(&master->bus_lock_mutex);
914
915 if (status == 0) {
916 wait_for_completion(&done);
917 status = message->status;
918 }
919 message->context = NULL;
920 return status;
921}
922
David Brownell8ae12a02006-01-08 13:34:19 -0800923/**
924 * spi_sync - blocking/synchronous SPI data transfers
925 * @spi: device with which data will be exchanged
926 * @message: describes the data transfers
David Brownell33e34dc2007-05-08 00:32:21 -0700927 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -0800928 *
929 * This call may only be used from a context that may sleep. The sleep
930 * is non-interruptible, and has no timeout. Low-overhead controller
931 * drivers may DMA directly into and out of the message buffers.
932 *
933 * Note that the SPI device's chip select is active during the message,
934 * and then is normally disabled between messages. Drivers for some
935 * frequently-used devices may want to minimize costs of selecting a chip,
936 * by leaving it selected in anticipation that the next message will go
937 * to the same chip. (That may increase power usage.)
938 *
David Brownell0c868462006-01-08 13:34:25 -0800939 * Also, the caller is guaranteeing that the memory associated with the
940 * message will not be freed before this call returns.
941 *
Marc Pignat9b938b72007-12-04 23:45:10 -0800942 * It returns zero on success, else a negative error code.
David Brownell8ae12a02006-01-08 13:34:19 -0800943 */
944int spi_sync(struct spi_device *spi, struct spi_message *message)
945{
Ernst Schwabcf32b712010-06-28 17:49:29 -0700946 return __spi_sync(spi, message, 0);
David Brownell8ae12a02006-01-08 13:34:19 -0800947}
948EXPORT_SYMBOL_GPL(spi_sync);
949
Ernst Schwabcf32b712010-06-28 17:49:29 -0700950/**
951 * spi_sync_locked - version of spi_sync with exclusive bus usage
952 * @spi: device with which data will be exchanged
953 * @message: describes the data transfers
954 * Context: can sleep
955 *
956 * This call may only be used from a context that may sleep. The sleep
957 * is non-interruptible, and has no timeout. Low-overhead controller
958 * drivers may DMA directly into and out of the message buffers.
959 *
960 * This call should be used by drivers that require exclusive access to the
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300961 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
Ernst Schwabcf32b712010-06-28 17:49:29 -0700962 * be released by a spi_bus_unlock call when the exclusive access is over.
963 *
964 * It returns zero on success, else a negative error code.
965 */
966int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
967{
968 return __spi_sync(spi, message, 1);
969}
970EXPORT_SYMBOL_GPL(spi_sync_locked);
971
972/**
973 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
974 * @master: SPI bus master that should be locked for exclusive bus access
975 * Context: can sleep
976 *
977 * This call may only be used from a context that may sleep. The sleep
978 * is non-interruptible, and has no timeout.
979 *
980 * This call should be used by drivers that require exclusive access to the
981 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
982 * exclusive access is over. Data transfer must be done by spi_sync_locked
983 * and spi_async_locked calls when the SPI bus lock is held.
984 *
985 * It returns zero on success, else a negative error code.
986 */
987int spi_bus_lock(struct spi_master *master)
988{
989 unsigned long flags;
990
991 mutex_lock(&master->bus_lock_mutex);
992
993 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
994 master->bus_lock_flag = 1;
995 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
996
997 /* mutex remains locked until spi_bus_unlock is called */
998
999 return 0;
1000}
1001EXPORT_SYMBOL_GPL(spi_bus_lock);
1002
1003/**
1004 * spi_bus_unlock - release the lock for exclusive SPI bus usage
1005 * @master: SPI bus master that was locked for exclusive bus access
1006 * Context: can sleep
1007 *
1008 * This call may only be used from a context that may sleep. The sleep
1009 * is non-interruptible, and has no timeout.
1010 *
1011 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
1012 * call.
1013 *
1014 * It returns zero on success, else a negative error code.
1015 */
1016int spi_bus_unlock(struct spi_master *master)
1017{
1018 master->bus_lock_flag = 0;
1019
1020 mutex_unlock(&master->bus_lock_mutex);
1021
1022 return 0;
1023}
1024EXPORT_SYMBOL_GPL(spi_bus_unlock);
1025
David Brownella9948b62006-04-02 10:37:40 -08001026/* portable code must never pass more than 32 bytes */
1027#define SPI_BUFSIZ max(32,SMP_CACHE_BYTES)
David Brownell8ae12a02006-01-08 13:34:19 -08001028
1029static u8 *buf;
1030
1031/**
1032 * spi_write_then_read - SPI synchronous write followed by read
1033 * @spi: device with which data will be exchanged
1034 * @txbuf: data to be written (need not be dma-safe)
1035 * @n_tx: size of txbuf, in bytes
Jiri Pirko27570492009-06-17 16:26:06 -07001036 * @rxbuf: buffer into which data will be read (need not be dma-safe)
1037 * @n_rx: size of rxbuf, in bytes
David Brownell33e34dc2007-05-08 00:32:21 -07001038 * Context: can sleep
David Brownell8ae12a02006-01-08 13:34:19 -08001039 *
1040 * This performs a half duplex MicroWire style transaction with the
1041 * device, sending txbuf and then reading rxbuf. The return value
1042 * is zero for success, else a negative errno status code.
David Brownellb8852442006-01-08 13:34:23 -08001043 * This call may only be used from a context that may sleep.
David Brownell8ae12a02006-01-08 13:34:19 -08001044 *
David Brownell0c868462006-01-08 13:34:25 -08001045 * Parameters to this routine are always copied using a small buffer;
David Brownell33e34dc2007-05-08 00:32:21 -07001046 * portable code should never use this for more than 32 bytes.
1047 * Performance-sensitive or bulk transfer code should instead use
David Brownell0c868462006-01-08 13:34:25 -08001048 * spi_{async,sync}() calls with dma-safe buffers.
David Brownell8ae12a02006-01-08 13:34:19 -08001049 */
1050int spi_write_then_read(struct spi_device *spi,
Mark Brown0c4a1592011-05-11 00:09:30 +02001051 const void *txbuf, unsigned n_tx,
1052 void *rxbuf, unsigned n_rx)
David Brownell8ae12a02006-01-08 13:34:19 -08001053{
David Brownell068f4072007-12-04 23:45:09 -08001054 static DEFINE_MUTEX(lock);
David Brownell8ae12a02006-01-08 13:34:19 -08001055
1056 int status;
1057 struct spi_message message;
David Brownellbdff5492009-04-13 14:39:57 -07001058 struct spi_transfer x[2];
David Brownell8ae12a02006-01-08 13:34:19 -08001059 u8 *local_buf;
1060
1061 /* Use preallocated DMA-safe buffer. We can't avoid copying here,
1062 * (as a pure convenience thing), but we can keep heap costs
1063 * out of the hot path ...
1064 */
1065 if ((n_tx + n_rx) > SPI_BUFSIZ)
1066 return -EINVAL;
1067
Vitaly Wool8275c642006-01-08 13:34:28 -08001068 spi_message_init(&message);
David Brownellbdff5492009-04-13 14:39:57 -07001069 memset(x, 0, sizeof x);
1070 if (n_tx) {
1071 x[0].len = n_tx;
1072 spi_message_add_tail(&x[0], &message);
1073 }
1074 if (n_rx) {
1075 x[1].len = n_rx;
1076 spi_message_add_tail(&x[1], &message);
1077 }
Vitaly Wool8275c642006-01-08 13:34:28 -08001078
David Brownell8ae12a02006-01-08 13:34:19 -08001079 /* ... unless someone else is using the pre-allocated buffer */
David Brownell068f4072007-12-04 23:45:09 -08001080 if (!mutex_trylock(&lock)) {
David Brownell8ae12a02006-01-08 13:34:19 -08001081 local_buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
1082 if (!local_buf)
1083 return -ENOMEM;
1084 } else
1085 local_buf = buf;
1086
David Brownell8ae12a02006-01-08 13:34:19 -08001087 memcpy(local_buf, txbuf, n_tx);
David Brownellbdff5492009-04-13 14:39:57 -07001088 x[0].tx_buf = local_buf;
1089 x[1].rx_buf = local_buf + n_tx;
David Brownell8ae12a02006-01-08 13:34:19 -08001090
1091 /* do the i/o */
David Brownell8ae12a02006-01-08 13:34:19 -08001092 status = spi_sync(spi, &message);
Marc Pignat9b938b72007-12-04 23:45:10 -08001093 if (status == 0)
David Brownellbdff5492009-04-13 14:39:57 -07001094 memcpy(rxbuf, x[1].rx_buf, n_rx);
David Brownell8ae12a02006-01-08 13:34:19 -08001095
David Brownellbdff5492009-04-13 14:39:57 -07001096 if (x[0].tx_buf == buf)
David Brownell068f4072007-12-04 23:45:09 -08001097 mutex_unlock(&lock);
David Brownell8ae12a02006-01-08 13:34:19 -08001098 else
1099 kfree(local_buf);
1100
1101 return status;
1102}
1103EXPORT_SYMBOL_GPL(spi_write_then_read);
1104
1105/*-------------------------------------------------------------------------*/
1106
1107static int __init spi_init(void)
1108{
David Brownellb8852442006-01-08 13:34:23 -08001109 int status;
David Brownell8ae12a02006-01-08 13:34:19 -08001110
Christoph Lametere94b1762006-12-06 20:33:17 -08001111 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
David Brownellb8852442006-01-08 13:34:23 -08001112 if (!buf) {
1113 status = -ENOMEM;
1114 goto err0;
1115 }
1116
1117 status = bus_register(&spi_bus_type);
1118 if (status < 0)
1119 goto err1;
1120
1121 status = class_register(&spi_master_class);
1122 if (status < 0)
1123 goto err2;
David Brownell8ae12a02006-01-08 13:34:19 -08001124 return 0;
David Brownellb8852442006-01-08 13:34:23 -08001125
1126err2:
1127 bus_unregister(&spi_bus_type);
1128err1:
1129 kfree(buf);
1130 buf = NULL;
1131err0:
1132 return status;
David Brownell8ae12a02006-01-08 13:34:19 -08001133}
David Brownellb8852442006-01-08 13:34:23 -08001134
David Brownell8ae12a02006-01-08 13:34:19 -08001135/* board_info is normally registered in arch_initcall(),
1136 * but even essential drivers wait till later
David Brownellb8852442006-01-08 13:34:23 -08001137 *
1138 * REVISIT only boardinfo really needs static linking. the rest (device and
1139 * driver registration) _could_ be dynamically linked (modular) ... costs
1140 * include needing to have boardinfo data structures be much more public.
David Brownell8ae12a02006-01-08 13:34:19 -08001141 */
David Brownell673c0c02008-10-15 22:02:46 -07001142postcore_initcall(spi_init);
David Brownell8ae12a02006-01-08 13:34:19 -08001143