David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 1 | /* |
Grant Likely | ca632f5 | 2011-06-06 01:16:30 -0600 | [diff] [blame] | 2 | * SPI init/core code |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 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 Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 21 | #include <linux/kernel.h> |
| 22 | #include <linux/device.h> |
| 23 | #include <linux/init.h> |
| 24 | #include <linux/cache.h> |
Matthias Kaehlcke | 9404082 | 2007-07-17 04:04:16 -0700 | [diff] [blame] | 25 | #include <linux/mutex.h> |
Sinan Akman | 2b7a32f | 2010-10-02 21:28:29 -0600 | [diff] [blame] | 26 | #include <linux/of_device.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 27 | #include <linux/slab.h> |
Anton Vorontsov | e0626e3 | 2009-09-22 16:46:08 -0700 | [diff] [blame] | 28 | #include <linux/mod_devicetable.h> |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 29 | #include <linux/spi/spi.h> |
Anatolij Gustschin | 12b15e8 | 2010-07-27 22:35:58 +0200 | [diff] [blame] | 30 | #include <linux/of_spi.h> |
Mark Brown | 3ae22e8 | 2010-12-25 15:32:27 +0100 | [diff] [blame] | 31 | #include <linux/pm_runtime.h> |
Paul Gortmaker | 025ed13 | 2011-07-10 12:57:55 -0400 | [diff] [blame] | 32 | #include <linux/export.h> |
Linus Walleij | ffbbdd21 | 2012-02-22 10:05:38 +0100 | [diff] [blame] | 33 | #include <linux/sched.h> |
| 34 | #include <linux/delay.h> |
| 35 | #include <linux/kthread.h> |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 36 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 37 | static void spidev_release(struct device *dev) |
| 38 | { |
Hans-Peter Nilsson | 0ffa028 | 2007-02-12 00:52:45 -0800 | [diff] [blame] | 39 | struct spi_device *spi = to_spi_device(dev); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 40 | |
| 41 | /* spi masters may cleanup for released devices */ |
| 42 | if (spi->master->cleanup) |
| 43 | spi->master->cleanup(spi); |
| 44 | |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 45 | spi_master_put(spi->master); |
Roman Tereshonkov | 07a389f | 2010-04-12 09:56:35 +0000 | [diff] [blame] | 46 | kfree(spi); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 47 | } |
| 48 | |
| 49 | static ssize_t |
| 50 | modalias_show(struct device *dev, struct device_attribute *a, char *buf) |
| 51 | { |
| 52 | const struct spi_device *spi = to_spi_device(dev); |
| 53 | |
Kay Sievers | 35f74fc | 2009-01-06 10:44:37 -0800 | [diff] [blame] | 54 | return sprintf(buf, "%s\n", spi->modalias); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 55 | } |
| 56 | |
| 57 | static struct device_attribute spi_dev_attrs[] = { |
| 58 | __ATTR_RO(modalias), |
| 59 | __ATTR_NULL, |
| 60 | }; |
| 61 | |
| 62 | /* modalias support makes "modprobe $MODALIAS" new-style hotplug work, |
| 63 | * and the sysfs version makes coldplug work too. |
| 64 | */ |
| 65 | |
Anton Vorontsov | 75368bf | 2009-09-22 16:46:04 -0700 | [diff] [blame] | 66 | static const struct spi_device_id *spi_match_id(const struct spi_device_id *id, |
| 67 | const struct spi_device *sdev) |
| 68 | { |
| 69 | while (id->name[0]) { |
| 70 | if (!strcmp(sdev->modalias, id->name)) |
| 71 | return id; |
| 72 | id++; |
| 73 | } |
| 74 | return NULL; |
| 75 | } |
| 76 | |
| 77 | const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev) |
| 78 | { |
| 79 | const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver); |
| 80 | |
| 81 | return spi_match_id(sdrv->id_table, sdev); |
| 82 | } |
| 83 | EXPORT_SYMBOL_GPL(spi_get_device_id); |
| 84 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 85 | static int spi_match_device(struct device *dev, struct device_driver *drv) |
| 86 | { |
| 87 | const struct spi_device *spi = to_spi_device(dev); |
Anton Vorontsov | 75368bf | 2009-09-22 16:46:04 -0700 | [diff] [blame] | 88 | const struct spi_driver *sdrv = to_spi_driver(drv); |
| 89 | |
Sinan Akman | 2b7a32f | 2010-10-02 21:28:29 -0600 | [diff] [blame] | 90 | /* Attempt an OF style match */ |
| 91 | if (of_driver_match_device(dev, drv)) |
| 92 | return 1; |
| 93 | |
Anton Vorontsov | 75368bf | 2009-09-22 16:46:04 -0700 | [diff] [blame] | 94 | if (sdrv->id_table) |
| 95 | return !!spi_match_id(sdrv->id_table, spi); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 96 | |
Kay Sievers | 35f74fc | 2009-01-06 10:44:37 -0800 | [diff] [blame] | 97 | return strcmp(spi->modalias, drv->name) == 0; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 98 | } |
| 99 | |
Kay Sievers | 7eff2e7 | 2007-08-14 15:15:12 +0200 | [diff] [blame] | 100 | static int spi_uevent(struct device *dev, struct kobj_uevent_env *env) |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 101 | { |
| 102 | const struct spi_device *spi = to_spi_device(dev); |
| 103 | |
Anton Vorontsov | e0626e3 | 2009-09-22 16:46:08 -0700 | [diff] [blame] | 104 | add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 105 | return 0; |
| 106 | } |
| 107 | |
Mark Brown | 3ae22e8 | 2010-12-25 15:32:27 +0100 | [diff] [blame] | 108 | #ifdef CONFIG_PM_SLEEP |
| 109 | static int spi_legacy_suspend(struct device *dev, pm_message_t message) |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 110 | { |
David Brownell | 3c72426 | 2008-02-06 01:38:10 -0800 | [diff] [blame] | 111 | int value = 0; |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 112 | struct spi_driver *drv = to_spi_driver(dev->driver); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 113 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 114 | /* suspend will stop irqs and dma; no more i/o */ |
David Brownell | 3c72426 | 2008-02-06 01:38:10 -0800 | [diff] [blame] | 115 | if (drv) { |
| 116 | if (drv->suspend) |
| 117 | value = drv->suspend(to_spi_device(dev), message); |
| 118 | else |
| 119 | dev_dbg(dev, "... can't suspend\n"); |
| 120 | } |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 121 | return value; |
| 122 | } |
| 123 | |
Mark Brown | 3ae22e8 | 2010-12-25 15:32:27 +0100 | [diff] [blame] | 124 | static int spi_legacy_resume(struct device *dev) |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 125 | { |
David Brownell | 3c72426 | 2008-02-06 01:38:10 -0800 | [diff] [blame] | 126 | int value = 0; |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 127 | struct spi_driver *drv = to_spi_driver(dev->driver); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 128 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 129 | /* resume may restart the i/o queue */ |
David Brownell | 3c72426 | 2008-02-06 01:38:10 -0800 | [diff] [blame] | 130 | if (drv) { |
| 131 | if (drv->resume) |
| 132 | value = drv->resume(to_spi_device(dev)); |
| 133 | else |
| 134 | dev_dbg(dev, "... can't resume\n"); |
| 135 | } |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 136 | return value; |
| 137 | } |
| 138 | |
Mark Brown | 3ae22e8 | 2010-12-25 15:32:27 +0100 | [diff] [blame] | 139 | static int spi_pm_suspend(struct device *dev) |
| 140 | { |
| 141 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; |
| 142 | |
| 143 | if (pm) |
| 144 | return pm_generic_suspend(dev); |
| 145 | else |
| 146 | return spi_legacy_suspend(dev, PMSG_SUSPEND); |
| 147 | } |
| 148 | |
| 149 | static int spi_pm_resume(struct device *dev) |
| 150 | { |
| 151 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; |
| 152 | |
| 153 | if (pm) |
| 154 | return pm_generic_resume(dev); |
| 155 | else |
| 156 | return spi_legacy_resume(dev); |
| 157 | } |
| 158 | |
| 159 | static int spi_pm_freeze(struct device *dev) |
| 160 | { |
| 161 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; |
| 162 | |
| 163 | if (pm) |
| 164 | return pm_generic_freeze(dev); |
| 165 | else |
| 166 | return spi_legacy_suspend(dev, PMSG_FREEZE); |
| 167 | } |
| 168 | |
| 169 | static int spi_pm_thaw(struct device *dev) |
| 170 | { |
| 171 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; |
| 172 | |
| 173 | if (pm) |
| 174 | return pm_generic_thaw(dev); |
| 175 | else |
| 176 | return spi_legacy_resume(dev); |
| 177 | } |
| 178 | |
| 179 | static int spi_pm_poweroff(struct device *dev) |
| 180 | { |
| 181 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; |
| 182 | |
| 183 | if (pm) |
| 184 | return pm_generic_poweroff(dev); |
| 185 | else |
| 186 | return spi_legacy_suspend(dev, PMSG_HIBERNATE); |
| 187 | } |
| 188 | |
| 189 | static int spi_pm_restore(struct device *dev) |
| 190 | { |
| 191 | const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; |
| 192 | |
| 193 | if (pm) |
| 194 | return pm_generic_restore(dev); |
| 195 | else |
| 196 | return spi_legacy_resume(dev); |
| 197 | } |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 198 | #else |
Mark Brown | 3ae22e8 | 2010-12-25 15:32:27 +0100 | [diff] [blame] | 199 | #define spi_pm_suspend NULL |
| 200 | #define spi_pm_resume NULL |
| 201 | #define spi_pm_freeze NULL |
| 202 | #define spi_pm_thaw NULL |
| 203 | #define spi_pm_poweroff NULL |
| 204 | #define spi_pm_restore NULL |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 205 | #endif |
| 206 | |
Mark Brown | 3ae22e8 | 2010-12-25 15:32:27 +0100 | [diff] [blame] | 207 | static const struct dev_pm_ops spi_pm = { |
| 208 | .suspend = spi_pm_suspend, |
| 209 | .resume = spi_pm_resume, |
| 210 | .freeze = spi_pm_freeze, |
| 211 | .thaw = spi_pm_thaw, |
| 212 | .poweroff = spi_pm_poweroff, |
| 213 | .restore = spi_pm_restore, |
| 214 | SET_RUNTIME_PM_OPS( |
| 215 | pm_generic_runtime_suspend, |
| 216 | pm_generic_runtime_resume, |
| 217 | pm_generic_runtime_idle |
| 218 | ) |
| 219 | }; |
| 220 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 221 | struct bus_type spi_bus_type = { |
| 222 | .name = "spi", |
| 223 | .dev_attrs = spi_dev_attrs, |
| 224 | .match = spi_match_device, |
| 225 | .uevent = spi_uevent, |
Mark Brown | 3ae22e8 | 2010-12-25 15:32:27 +0100 | [diff] [blame] | 226 | .pm = &spi_pm, |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 227 | }; |
| 228 | EXPORT_SYMBOL_GPL(spi_bus_type); |
| 229 | |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 230 | |
| 231 | static int spi_drv_probe(struct device *dev) |
| 232 | { |
| 233 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); |
| 234 | |
| 235 | return sdrv->probe(to_spi_device(dev)); |
| 236 | } |
| 237 | |
| 238 | static int spi_drv_remove(struct device *dev) |
| 239 | { |
| 240 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); |
| 241 | |
| 242 | return sdrv->remove(to_spi_device(dev)); |
| 243 | } |
| 244 | |
| 245 | static void spi_drv_shutdown(struct device *dev) |
| 246 | { |
| 247 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); |
| 248 | |
| 249 | sdrv->shutdown(to_spi_device(dev)); |
| 250 | } |
| 251 | |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 252 | /** |
| 253 | * spi_register_driver - register a SPI driver |
| 254 | * @sdrv: the driver to register |
| 255 | * Context: can sleep |
| 256 | */ |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 257 | int spi_register_driver(struct spi_driver *sdrv) |
| 258 | { |
| 259 | sdrv->driver.bus = &spi_bus_type; |
| 260 | if (sdrv->probe) |
| 261 | sdrv->driver.probe = spi_drv_probe; |
| 262 | if (sdrv->remove) |
| 263 | sdrv->driver.remove = spi_drv_remove; |
| 264 | if (sdrv->shutdown) |
| 265 | sdrv->driver.shutdown = spi_drv_shutdown; |
| 266 | return driver_register(&sdrv->driver); |
| 267 | } |
| 268 | EXPORT_SYMBOL_GPL(spi_register_driver); |
| 269 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 270 | /*-------------------------------------------------------------------------*/ |
| 271 | |
| 272 | /* SPI devices should normally not be created by SPI device drivers; that |
| 273 | * would make them board-specific. Similarly with SPI master drivers. |
| 274 | * Device registration normally goes into like arch/.../mach.../board-YYY.c |
| 275 | * with other readonly (flashable) information about mainboard devices. |
| 276 | */ |
| 277 | |
| 278 | struct boardinfo { |
| 279 | struct list_head list; |
Feng Tang | 2b9603a | 2010-08-02 15:52:15 +0800 | [diff] [blame] | 280 | struct spi_board_info board_info; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 281 | }; |
| 282 | |
| 283 | static LIST_HEAD(board_list); |
Feng Tang | 2b9603a | 2010-08-02 15:52:15 +0800 | [diff] [blame] | 284 | static LIST_HEAD(spi_master_list); |
| 285 | |
| 286 | /* |
| 287 | * Used to protect add/del opertion for board_info list and |
| 288 | * spi_master list, and their matching process |
| 289 | */ |
Matthias Kaehlcke | 9404082 | 2007-07-17 04:04:16 -0700 | [diff] [blame] | 290 | static DEFINE_MUTEX(board_lock); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 291 | |
Grant Likely | dc87c98 | 2008-05-15 16:50:22 -0600 | [diff] [blame] | 292 | /** |
| 293 | * spi_alloc_device - Allocate a new SPI device |
| 294 | * @master: Controller to which device is connected |
| 295 | * Context: can sleep |
| 296 | * |
| 297 | * Allows a driver to allocate and initialize a spi_device without |
| 298 | * registering it immediately. This allows a driver to directly |
| 299 | * fill the spi_device with device parameters before calling |
| 300 | * spi_add_device() on it. |
| 301 | * |
| 302 | * Caller is responsible to call spi_add_device() on the returned |
| 303 | * spi_device structure to add it to the SPI master. If the caller |
| 304 | * needs to discard the spi_device without adding it, then it should |
| 305 | * call spi_dev_put() on it. |
| 306 | * |
| 307 | * Returns a pointer to the new device, or NULL. |
| 308 | */ |
| 309 | struct spi_device *spi_alloc_device(struct spi_master *master) |
| 310 | { |
| 311 | struct spi_device *spi; |
| 312 | struct device *dev = master->dev.parent; |
| 313 | |
| 314 | if (!spi_master_get(master)) |
| 315 | return NULL; |
| 316 | |
| 317 | spi = kzalloc(sizeof *spi, GFP_KERNEL); |
| 318 | if (!spi) { |
| 319 | dev_err(dev, "cannot alloc spi_device\n"); |
| 320 | spi_master_put(master); |
| 321 | return NULL; |
| 322 | } |
| 323 | |
| 324 | spi->master = master; |
Laurent Pinchart | 178db7d | 2011-12-12 01:15:06 +0100 | [diff] [blame] | 325 | spi->dev.parent = &master->dev; |
Grant Likely | dc87c98 | 2008-05-15 16:50:22 -0600 | [diff] [blame] | 326 | spi->dev.bus = &spi_bus_type; |
| 327 | spi->dev.release = spidev_release; |
| 328 | device_initialize(&spi->dev); |
| 329 | return spi; |
| 330 | } |
| 331 | EXPORT_SYMBOL_GPL(spi_alloc_device); |
| 332 | |
| 333 | /** |
| 334 | * spi_add_device - Add spi_device allocated with spi_alloc_device |
| 335 | * @spi: spi_device to register |
| 336 | * |
| 337 | * Companion function to spi_alloc_device. Devices allocated with |
| 338 | * spi_alloc_device can be added onto the spi bus with this function. |
| 339 | * |
David Brownell | e48880e | 2008-08-15 00:40:44 -0700 | [diff] [blame] | 340 | * Returns 0 on success; negative errno on failure |
Grant Likely | dc87c98 | 2008-05-15 16:50:22 -0600 | [diff] [blame] | 341 | */ |
| 342 | int spi_add_device(struct spi_device *spi) |
| 343 | { |
David Brownell | e48880e | 2008-08-15 00:40:44 -0700 | [diff] [blame] | 344 | static DEFINE_MUTEX(spi_add_lock); |
Grant Likely | dc87c98 | 2008-05-15 16:50:22 -0600 | [diff] [blame] | 345 | struct device *dev = spi->master->dev.parent; |
Roman Tereshonkov | 8ec130a | 2010-04-16 09:52:59 +0000 | [diff] [blame] | 346 | struct device *d; |
Grant Likely | dc87c98 | 2008-05-15 16:50:22 -0600 | [diff] [blame] | 347 | int status; |
| 348 | |
| 349 | /* Chipselects are numbered 0..max; validate. */ |
| 350 | if (spi->chip_select >= spi->master->num_chipselect) { |
| 351 | dev_err(dev, "cs%d >= max %d\n", |
| 352 | spi->chip_select, |
| 353 | spi->master->num_chipselect); |
| 354 | return -EINVAL; |
| 355 | } |
| 356 | |
| 357 | /* Set the bus ID string */ |
Kay Sievers | 35f74fc | 2009-01-06 10:44:37 -0800 | [diff] [blame] | 358 | dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev), |
Grant Likely | dc87c98 | 2008-05-15 16:50:22 -0600 | [diff] [blame] | 359 | spi->chip_select); |
| 360 | |
David Brownell | e48880e | 2008-08-15 00:40:44 -0700 | [diff] [blame] | 361 | |
| 362 | /* We need to make sure there's no other device with this |
| 363 | * chipselect **BEFORE** we call setup(), else we'll trash |
| 364 | * its configuration. Lock against concurrent add() calls. |
| 365 | */ |
| 366 | mutex_lock(&spi_add_lock); |
| 367 | |
Roman Tereshonkov | 8ec130a | 2010-04-16 09:52:59 +0000 | [diff] [blame] | 368 | d = bus_find_device_by_name(&spi_bus_type, NULL, dev_name(&spi->dev)); |
| 369 | if (d != NULL) { |
David Brownell | e48880e | 2008-08-15 00:40:44 -0700 | [diff] [blame] | 370 | dev_err(dev, "chipselect %d already in use\n", |
| 371 | spi->chip_select); |
Roman Tereshonkov | 8ec130a | 2010-04-16 09:52:59 +0000 | [diff] [blame] | 372 | put_device(d); |
David Brownell | e48880e | 2008-08-15 00:40:44 -0700 | [diff] [blame] | 373 | status = -EBUSY; |
| 374 | goto done; |
| 375 | } |
| 376 | |
| 377 | /* Drivers may modify this initial i/o setup, but will |
| 378 | * normally rely on the device being setup. Devices |
| 379 | * using SPI_CS_HIGH can't coexist well otherwise... |
| 380 | */ |
David Brownell | 7d07719 | 2009-06-17 16:26:03 -0700 | [diff] [blame] | 381 | status = spi_setup(spi); |
Grant Likely | dc87c98 | 2008-05-15 16:50:22 -0600 | [diff] [blame] | 382 | if (status < 0) { |
Linus Walleij | eb288a1 | 2010-10-21 21:06:44 +0200 | [diff] [blame] | 383 | dev_err(dev, "can't setup %s, status %d\n", |
| 384 | dev_name(&spi->dev), status); |
David Brownell | e48880e | 2008-08-15 00:40:44 -0700 | [diff] [blame] | 385 | goto done; |
Grant Likely | dc87c98 | 2008-05-15 16:50:22 -0600 | [diff] [blame] | 386 | } |
| 387 | |
David Brownell | e48880e | 2008-08-15 00:40:44 -0700 | [diff] [blame] | 388 | /* Device may be bound to an active driver when this returns */ |
Grant Likely | dc87c98 | 2008-05-15 16:50:22 -0600 | [diff] [blame] | 389 | status = device_add(&spi->dev); |
David Brownell | e48880e | 2008-08-15 00:40:44 -0700 | [diff] [blame] | 390 | if (status < 0) |
Linus Walleij | eb288a1 | 2010-10-21 21:06:44 +0200 | [diff] [blame] | 391 | dev_err(dev, "can't add %s, status %d\n", |
| 392 | dev_name(&spi->dev), status); |
David Brownell | e48880e | 2008-08-15 00:40:44 -0700 | [diff] [blame] | 393 | else |
Kay Sievers | 35f74fc | 2009-01-06 10:44:37 -0800 | [diff] [blame] | 394 | dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev)); |
Grant Likely | dc87c98 | 2008-05-15 16:50:22 -0600 | [diff] [blame] | 395 | |
David Brownell | e48880e | 2008-08-15 00:40:44 -0700 | [diff] [blame] | 396 | done: |
| 397 | mutex_unlock(&spi_add_lock); |
| 398 | return status; |
Grant Likely | dc87c98 | 2008-05-15 16:50:22 -0600 | [diff] [blame] | 399 | } |
| 400 | EXPORT_SYMBOL_GPL(spi_add_device); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 401 | |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 402 | /** |
| 403 | * spi_new_device - instantiate one new SPI device |
| 404 | * @master: Controller to which device is connected |
| 405 | * @chip: Describes the SPI device |
| 406 | * Context: can sleep |
| 407 | * |
| 408 | * On typical mainboards, this is purely internal; and it's not needed |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 409 | * after board init creates the hard-wired devices. Some development |
| 410 | * platforms may not be able to use spi_register_board_info though, and |
| 411 | * this is exported so that for example a USB or parport based adapter |
| 412 | * driver could add devices (which it would learn about out-of-band). |
David Brownell | 082c8cb | 2007-07-31 00:39:45 -0700 | [diff] [blame] | 413 | * |
| 414 | * Returns the new device, or NULL. |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 415 | */ |
Adrian Bunk | e9d5a46 | 2007-03-26 21:32:23 -0800 | [diff] [blame] | 416 | struct spi_device *spi_new_device(struct spi_master *master, |
| 417 | struct spi_board_info *chip) |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 418 | { |
| 419 | struct spi_device *proxy; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 420 | int status; |
| 421 | |
David Brownell | 082c8cb | 2007-07-31 00:39:45 -0700 | [diff] [blame] | 422 | /* NOTE: caller did any chip->bus_num checks necessary. |
| 423 | * |
| 424 | * Also, unless we change the return value convention to use |
| 425 | * error-or-pointer (not NULL-or-pointer), troubleshootability |
| 426 | * suggests syslogged diagnostics are best here (ugh). |
| 427 | */ |
| 428 | |
Grant Likely | dc87c98 | 2008-05-15 16:50:22 -0600 | [diff] [blame] | 429 | proxy = spi_alloc_device(master); |
| 430 | if (!proxy) |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 431 | return NULL; |
| 432 | |
Grant Likely | 102eb97 | 2008-07-23 21:29:55 -0700 | [diff] [blame] | 433 | WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias)); |
| 434 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 435 | proxy->chip_select = chip->chip_select; |
| 436 | proxy->max_speed_hz = chip->max_speed_hz; |
David Brownell | 980a01c | 2006-06-28 07:47:15 -0700 | [diff] [blame] | 437 | proxy->mode = chip->mode; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 438 | proxy->irq = chip->irq; |
Grant Likely | 102eb97 | 2008-07-23 21:29:55 -0700 | [diff] [blame] | 439 | strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias)); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 440 | proxy->dev.platform_data = (void *) chip->platform_data; |
| 441 | proxy->controller_data = chip->controller_data; |
| 442 | proxy->controller_state = NULL; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 443 | |
Grant Likely | dc87c98 | 2008-05-15 16:50:22 -0600 | [diff] [blame] | 444 | status = spi_add_device(proxy); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 445 | if (status < 0) { |
Grant Likely | dc87c98 | 2008-05-15 16:50:22 -0600 | [diff] [blame] | 446 | spi_dev_put(proxy); |
| 447 | return NULL; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 448 | } |
| 449 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 450 | return proxy; |
| 451 | } |
| 452 | EXPORT_SYMBOL_GPL(spi_new_device); |
| 453 | |
Feng Tang | 2b9603a | 2010-08-02 15:52:15 +0800 | [diff] [blame] | 454 | static void spi_match_master_to_boardinfo(struct spi_master *master, |
| 455 | struct spi_board_info *bi) |
| 456 | { |
| 457 | struct spi_device *dev; |
| 458 | |
| 459 | if (master->bus_num != bi->bus_num) |
| 460 | return; |
| 461 | |
| 462 | dev = spi_new_device(master, bi); |
| 463 | if (!dev) |
| 464 | dev_err(master->dev.parent, "can't create new device for %s\n", |
| 465 | bi->modalias); |
| 466 | } |
| 467 | |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 468 | /** |
| 469 | * spi_register_board_info - register SPI devices for a given board |
| 470 | * @info: array of chip descriptors |
| 471 | * @n: how many descriptors are provided |
| 472 | * Context: can sleep |
| 473 | * |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 474 | * Board-specific early init code calls this (probably during arch_initcall) |
| 475 | * with segments of the SPI device table. Any device nodes are created later, |
| 476 | * after the relevant parent SPI controller (bus_num) is defined. We keep |
| 477 | * this table of devices forever, so that reloading a controller driver will |
| 478 | * not make Linux forget about these hard-wired devices. |
| 479 | * |
| 480 | * Other code can also call this, e.g. a particular add-on board might provide |
| 481 | * SPI devices through its expansion connector, so code initializing that board |
| 482 | * would naturally declare its SPI devices. |
| 483 | * |
| 484 | * The board info passed can safely be __initdata ... but be careful of |
| 485 | * any embedded pointers (platform_data, etc), they're copied as-is. |
| 486 | */ |
| 487 | int __init |
| 488 | spi_register_board_info(struct spi_board_info const *info, unsigned n) |
| 489 | { |
Feng Tang | 2b9603a | 2010-08-02 15:52:15 +0800 | [diff] [blame] | 490 | struct boardinfo *bi; |
| 491 | int i; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 492 | |
Feng Tang | 2b9603a | 2010-08-02 15:52:15 +0800 | [diff] [blame] | 493 | bi = kzalloc(n * sizeof(*bi), GFP_KERNEL); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 494 | if (!bi) |
| 495 | return -ENOMEM; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 496 | |
Feng Tang | 2b9603a | 2010-08-02 15:52:15 +0800 | [diff] [blame] | 497 | for (i = 0; i < n; i++, bi++, info++) { |
| 498 | struct spi_master *master; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 499 | |
Feng Tang | 2b9603a | 2010-08-02 15:52:15 +0800 | [diff] [blame] | 500 | memcpy(&bi->board_info, info, sizeof(*info)); |
| 501 | mutex_lock(&board_lock); |
| 502 | list_add_tail(&bi->list, &board_list); |
| 503 | list_for_each_entry(master, &spi_master_list, list) |
| 504 | spi_match_master_to_boardinfo(master, &bi->board_info); |
| 505 | mutex_unlock(&board_lock); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 506 | } |
Feng Tang | 2b9603a | 2010-08-02 15:52:15 +0800 | [diff] [blame] | 507 | |
| 508 | return 0; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 509 | } |
| 510 | |
| 511 | /*-------------------------------------------------------------------------*/ |
| 512 | |
Linus Walleij | ffbbdd21 | 2012-02-22 10:05:38 +0100 | [diff] [blame] | 513 | /** |
| 514 | * spi_pump_messages - kthread work function which processes spi message queue |
| 515 | * @work: pointer to kthread work struct contained in the master struct |
| 516 | * |
| 517 | * This function checks if there is any spi message in the queue that |
| 518 | * needs processing and if so call out to the driver to initialize hardware |
| 519 | * and transfer each message. |
| 520 | * |
| 521 | */ |
| 522 | static void spi_pump_messages(struct kthread_work *work) |
| 523 | { |
| 524 | struct spi_master *master = |
| 525 | container_of(work, struct spi_master, pump_messages); |
| 526 | unsigned long flags; |
| 527 | bool was_busy = false; |
| 528 | int ret; |
| 529 | |
| 530 | /* Lock queue and check for queue work */ |
| 531 | spin_lock_irqsave(&master->queue_lock, flags); |
| 532 | if (list_empty(&master->queue) || !master->running) { |
| 533 | if (master->busy) { |
| 534 | ret = master->unprepare_transfer_hardware(master); |
| 535 | if (ret) { |
| 536 | dev_err(&master->dev, |
| 537 | "failed to unprepare transfer hardware\n"); |
| 538 | return; |
| 539 | } |
| 540 | } |
| 541 | master->busy = false; |
| 542 | spin_unlock_irqrestore(&master->queue_lock, flags); |
| 543 | return; |
| 544 | } |
| 545 | |
| 546 | /* Make sure we are not already running a message */ |
| 547 | if (master->cur_msg) { |
| 548 | spin_unlock_irqrestore(&master->queue_lock, flags); |
| 549 | return; |
| 550 | } |
| 551 | /* Extract head of queue */ |
| 552 | master->cur_msg = |
| 553 | list_entry(master->queue.next, struct spi_message, queue); |
| 554 | |
| 555 | list_del_init(&master->cur_msg->queue); |
| 556 | if (master->busy) |
| 557 | was_busy = true; |
| 558 | else |
| 559 | master->busy = true; |
| 560 | spin_unlock_irqrestore(&master->queue_lock, flags); |
| 561 | |
| 562 | if (!was_busy) { |
| 563 | ret = master->prepare_transfer_hardware(master); |
| 564 | if (ret) { |
| 565 | dev_err(&master->dev, |
| 566 | "failed to prepare transfer hardware\n"); |
| 567 | return; |
| 568 | } |
| 569 | } |
| 570 | |
| 571 | ret = master->transfer_one_message(master, master->cur_msg); |
| 572 | if (ret) { |
| 573 | dev_err(&master->dev, |
| 574 | "failed to transfer one message from queue\n"); |
| 575 | return; |
| 576 | } |
| 577 | } |
| 578 | |
| 579 | static int spi_init_queue(struct spi_master *master) |
| 580 | { |
| 581 | struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 }; |
| 582 | |
| 583 | INIT_LIST_HEAD(&master->queue); |
| 584 | spin_lock_init(&master->queue_lock); |
| 585 | |
| 586 | master->running = false; |
| 587 | master->busy = false; |
| 588 | |
| 589 | init_kthread_worker(&master->kworker); |
| 590 | master->kworker_task = kthread_run(kthread_worker_fn, |
| 591 | &master->kworker, |
| 592 | dev_name(&master->dev)); |
| 593 | if (IS_ERR(master->kworker_task)) { |
| 594 | dev_err(&master->dev, "failed to create message pump task\n"); |
| 595 | return -ENOMEM; |
| 596 | } |
| 597 | init_kthread_work(&master->pump_messages, spi_pump_messages); |
| 598 | |
| 599 | /* |
| 600 | * Master config will indicate if this controller should run the |
| 601 | * message pump with high (realtime) priority to reduce the transfer |
| 602 | * latency on the bus by minimising the delay between a transfer |
| 603 | * request and the scheduling of the message pump thread. Without this |
| 604 | * setting the message pump thread will remain at default priority. |
| 605 | */ |
| 606 | if (master->rt) { |
| 607 | dev_info(&master->dev, |
| 608 | "will run message pump with realtime priority\n"); |
| 609 | sched_setscheduler(master->kworker_task, SCHED_FIFO, ¶m); |
| 610 | } |
| 611 | |
| 612 | return 0; |
| 613 | } |
| 614 | |
| 615 | /** |
| 616 | * spi_get_next_queued_message() - called by driver to check for queued |
| 617 | * messages |
| 618 | * @master: the master to check for queued messages |
| 619 | * |
| 620 | * If there are more messages in the queue, the next message is returned from |
| 621 | * this call. |
| 622 | */ |
| 623 | struct spi_message *spi_get_next_queued_message(struct spi_master *master) |
| 624 | { |
| 625 | struct spi_message *next; |
| 626 | unsigned long flags; |
| 627 | |
| 628 | /* get a pointer to the next message, if any */ |
| 629 | spin_lock_irqsave(&master->queue_lock, flags); |
| 630 | if (list_empty(&master->queue)) |
| 631 | next = NULL; |
| 632 | else |
| 633 | next = list_entry(master->queue.next, |
| 634 | struct spi_message, queue); |
| 635 | spin_unlock_irqrestore(&master->queue_lock, flags); |
| 636 | |
| 637 | return next; |
| 638 | } |
| 639 | EXPORT_SYMBOL_GPL(spi_get_next_queued_message); |
| 640 | |
| 641 | /** |
| 642 | * spi_finalize_current_message() - the current message is complete |
| 643 | * @master: the master to return the message to |
| 644 | * |
| 645 | * Called by the driver to notify the core that the message in the front of the |
| 646 | * queue is complete and can be removed from the queue. |
| 647 | */ |
| 648 | void spi_finalize_current_message(struct spi_master *master) |
| 649 | { |
| 650 | struct spi_message *mesg; |
| 651 | unsigned long flags; |
| 652 | |
| 653 | spin_lock_irqsave(&master->queue_lock, flags); |
| 654 | mesg = master->cur_msg; |
| 655 | master->cur_msg = NULL; |
| 656 | |
| 657 | queue_kthread_work(&master->kworker, &master->pump_messages); |
| 658 | spin_unlock_irqrestore(&master->queue_lock, flags); |
| 659 | |
| 660 | mesg->state = NULL; |
| 661 | if (mesg->complete) |
| 662 | mesg->complete(mesg->context); |
| 663 | } |
| 664 | EXPORT_SYMBOL_GPL(spi_finalize_current_message); |
| 665 | |
| 666 | static int spi_start_queue(struct spi_master *master) |
| 667 | { |
| 668 | unsigned long flags; |
| 669 | |
| 670 | spin_lock_irqsave(&master->queue_lock, flags); |
| 671 | |
| 672 | if (master->running || master->busy) { |
| 673 | spin_unlock_irqrestore(&master->queue_lock, flags); |
| 674 | return -EBUSY; |
| 675 | } |
| 676 | |
| 677 | master->running = true; |
| 678 | master->cur_msg = NULL; |
| 679 | spin_unlock_irqrestore(&master->queue_lock, flags); |
| 680 | |
| 681 | queue_kthread_work(&master->kworker, &master->pump_messages); |
| 682 | |
| 683 | return 0; |
| 684 | } |
| 685 | |
| 686 | static int spi_stop_queue(struct spi_master *master) |
| 687 | { |
| 688 | unsigned long flags; |
| 689 | unsigned limit = 500; |
| 690 | int ret = 0; |
| 691 | |
| 692 | spin_lock_irqsave(&master->queue_lock, flags); |
| 693 | |
| 694 | /* |
| 695 | * This is a bit lame, but is optimized for the common execution path. |
| 696 | * A wait_queue on the master->busy could be used, but then the common |
| 697 | * execution path (pump_messages) would be required to call wake_up or |
| 698 | * friends on every SPI message. Do this instead. |
| 699 | */ |
| 700 | while ((!list_empty(&master->queue) || master->busy) && limit--) { |
| 701 | spin_unlock_irqrestore(&master->queue_lock, flags); |
| 702 | msleep(10); |
| 703 | spin_lock_irqsave(&master->queue_lock, flags); |
| 704 | } |
| 705 | |
| 706 | if (!list_empty(&master->queue) || master->busy) |
| 707 | ret = -EBUSY; |
| 708 | else |
| 709 | master->running = false; |
| 710 | |
| 711 | spin_unlock_irqrestore(&master->queue_lock, flags); |
| 712 | |
| 713 | if (ret) { |
| 714 | dev_warn(&master->dev, |
| 715 | "could not stop message queue\n"); |
| 716 | return ret; |
| 717 | } |
| 718 | return ret; |
| 719 | } |
| 720 | |
| 721 | static int spi_destroy_queue(struct spi_master *master) |
| 722 | { |
| 723 | int ret; |
| 724 | |
| 725 | ret = spi_stop_queue(master); |
| 726 | |
| 727 | /* |
| 728 | * flush_kthread_worker will block until all work is done. |
| 729 | * If the reason that stop_queue timed out is that the work will never |
| 730 | * finish, then it does no good to call flush/stop thread, so |
| 731 | * return anyway. |
| 732 | */ |
| 733 | if (ret) { |
| 734 | dev_err(&master->dev, "problem destroying queue\n"); |
| 735 | return ret; |
| 736 | } |
| 737 | |
| 738 | flush_kthread_worker(&master->kworker); |
| 739 | kthread_stop(master->kworker_task); |
| 740 | |
| 741 | return 0; |
| 742 | } |
| 743 | |
| 744 | /** |
| 745 | * spi_queued_transfer - transfer function for queued transfers |
| 746 | * @spi: spi device which is requesting transfer |
| 747 | * @msg: spi message which is to handled is queued to driver queue |
| 748 | */ |
| 749 | static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg) |
| 750 | { |
| 751 | struct spi_master *master = spi->master; |
| 752 | unsigned long flags; |
| 753 | |
| 754 | spin_lock_irqsave(&master->queue_lock, flags); |
| 755 | |
| 756 | if (!master->running) { |
| 757 | spin_unlock_irqrestore(&master->queue_lock, flags); |
| 758 | return -ESHUTDOWN; |
| 759 | } |
| 760 | msg->actual_length = 0; |
| 761 | msg->status = -EINPROGRESS; |
| 762 | |
| 763 | list_add_tail(&msg->queue, &master->queue); |
| 764 | if (master->running && !master->busy) |
| 765 | queue_kthread_work(&master->kworker, &master->pump_messages); |
| 766 | |
| 767 | spin_unlock_irqrestore(&master->queue_lock, flags); |
| 768 | return 0; |
| 769 | } |
| 770 | |
| 771 | static int spi_master_initialize_queue(struct spi_master *master) |
| 772 | { |
| 773 | int ret; |
| 774 | |
| 775 | master->queued = true; |
| 776 | master->transfer = spi_queued_transfer; |
| 777 | |
| 778 | /* Initialize and start queue */ |
| 779 | ret = spi_init_queue(master); |
| 780 | if (ret) { |
| 781 | dev_err(&master->dev, "problem initializing queue\n"); |
| 782 | goto err_init_queue; |
| 783 | } |
| 784 | ret = spi_start_queue(master); |
| 785 | if (ret) { |
| 786 | dev_err(&master->dev, "problem starting queue\n"); |
| 787 | goto err_start_queue; |
| 788 | } |
| 789 | |
| 790 | return 0; |
| 791 | |
| 792 | err_start_queue: |
| 793 | err_init_queue: |
| 794 | spi_destroy_queue(master); |
| 795 | return ret; |
| 796 | } |
| 797 | |
| 798 | /*-------------------------------------------------------------------------*/ |
| 799 | |
Tony Jones | 49dce68 | 2007-10-16 01:27:48 -0700 | [diff] [blame] | 800 | static void spi_master_release(struct device *dev) |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 801 | { |
| 802 | struct spi_master *master; |
| 803 | |
Tony Jones | 49dce68 | 2007-10-16 01:27:48 -0700 | [diff] [blame] | 804 | master = container_of(dev, struct spi_master, dev); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 805 | kfree(master); |
| 806 | } |
| 807 | |
| 808 | static struct class spi_master_class = { |
| 809 | .name = "spi_master", |
| 810 | .owner = THIS_MODULE, |
Tony Jones | 49dce68 | 2007-10-16 01:27:48 -0700 | [diff] [blame] | 811 | .dev_release = spi_master_release, |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 812 | }; |
| 813 | |
| 814 | |
Linus Walleij | ffbbdd21 | 2012-02-22 10:05:38 +0100 | [diff] [blame] | 815 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 816 | /** |
| 817 | * spi_alloc_master - allocate SPI master controller |
| 818 | * @dev: the controller, possibly using the platform_bus |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 819 | * @size: how much zeroed driver-private data to allocate; the pointer to this |
Tony Jones | 49dce68 | 2007-10-16 01:27:48 -0700 | [diff] [blame] | 820 | * memory is in the driver_data field of the returned device, |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 821 | * accessible with spi_master_get_devdata(). |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 822 | * Context: can sleep |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 823 | * |
| 824 | * This call is used only by SPI master controller drivers, which are the |
| 825 | * only ones directly touching chip registers. It's how they allocate |
dmitry pervushin | ba1a051 | 2006-05-20 15:00:14 -0700 | [diff] [blame] | 826 | * an spi_master structure, prior to calling spi_register_master(). |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 827 | * |
| 828 | * This must be called from context that can sleep. It returns the SPI |
| 829 | * master structure on success, else NULL. |
| 830 | * |
| 831 | * The caller is responsible for assigning the bus number and initializing |
dmitry pervushin | ba1a051 | 2006-05-20 15:00:14 -0700 | [diff] [blame] | 832 | * the master's methods before calling spi_register_master(); and (after errors |
Uwe Kleine-König | eb4af0f | 2012-02-23 10:40:14 +0100 | [diff] [blame^] | 833 | * adding the device) calling spi_master_put() and kfree() to prevent a memory |
| 834 | * leak. |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 835 | */ |
Adrian Bunk | e9d5a46 | 2007-03-26 21:32:23 -0800 | [diff] [blame] | 836 | struct spi_master *spi_alloc_master(struct device *dev, unsigned size) |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 837 | { |
| 838 | struct spi_master *master; |
| 839 | |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 840 | if (!dev) |
| 841 | return NULL; |
| 842 | |
Christoph Lameter | e94b176 | 2006-12-06 20:33:17 -0800 | [diff] [blame] | 843 | master = kzalloc(size + sizeof *master, GFP_KERNEL); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 844 | if (!master) |
| 845 | return NULL; |
| 846 | |
Tony Jones | 49dce68 | 2007-10-16 01:27:48 -0700 | [diff] [blame] | 847 | device_initialize(&master->dev); |
| 848 | master->dev.class = &spi_master_class; |
| 849 | master->dev.parent = get_device(dev); |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 850 | spi_master_set_devdata(master, &master[1]); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 851 | |
| 852 | return master; |
| 853 | } |
| 854 | EXPORT_SYMBOL_GPL(spi_alloc_master); |
| 855 | |
| 856 | /** |
| 857 | * spi_register_master - register SPI master controller |
| 858 | * @master: initialized master, originally from spi_alloc_master() |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 859 | * Context: can sleep |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 860 | * |
| 861 | * SPI master controllers connect to their drivers using some non-SPI bus, |
| 862 | * such as the platform bus. The final stage of probe() in that code |
| 863 | * includes calling spi_register_master() to hook up to this SPI bus glue. |
| 864 | * |
| 865 | * SPI controllers use board specific (often SOC specific) bus numbers, |
| 866 | * and board-specific addressing for SPI devices combines those numbers |
| 867 | * with chip select numbers. Since SPI does not directly support dynamic |
| 868 | * device identification, boards need configuration tables telling which |
| 869 | * chip is at which address. |
| 870 | * |
| 871 | * This must be called from context that can sleep. It returns zero on |
| 872 | * success, else a negative error code (dropping the master's refcount). |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 873 | * After a successful return, the caller is responsible for calling |
| 874 | * spi_unregister_master(). |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 875 | */ |
Adrian Bunk | e9d5a46 | 2007-03-26 21:32:23 -0800 | [diff] [blame] | 876 | int spi_register_master(struct spi_master *master) |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 877 | { |
David Brownell | e44a45a | 2007-06-03 13:50:40 -0700 | [diff] [blame] | 878 | static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1); |
Tony Jones | 49dce68 | 2007-10-16 01:27:48 -0700 | [diff] [blame] | 879 | struct device *dev = master->dev.parent; |
Feng Tang | 2b9603a | 2010-08-02 15:52:15 +0800 | [diff] [blame] | 880 | struct boardinfo *bi; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 881 | int status = -ENODEV; |
| 882 | int dynamic = 0; |
| 883 | |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 884 | if (!dev) |
| 885 | return -ENODEV; |
| 886 | |
David Brownell | 082c8cb | 2007-07-31 00:39:45 -0700 | [diff] [blame] | 887 | /* even if it's just one always-selected device, there must |
| 888 | * be at least one chipselect |
| 889 | */ |
| 890 | if (master->num_chipselect == 0) |
| 891 | return -EINVAL; |
| 892 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 893 | /* convention: dynamically assigned bus IDs count down from the max */ |
David Brownell | a020ed7 | 2006-04-03 15:49:04 -0700 | [diff] [blame] | 894 | if (master->bus_num < 0) { |
David Brownell | 082c8cb | 2007-07-31 00:39:45 -0700 | [diff] [blame] | 895 | /* FIXME switch to an IDR based scheme, something like |
| 896 | * I2C now uses, so we can't run out of "dynamic" IDs |
| 897 | */ |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 898 | master->bus_num = atomic_dec_return(&dyn_bus_id); |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 899 | dynamic = 1; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 900 | } |
| 901 | |
Ernst Schwab | cf32b71 | 2010-06-28 17:49:29 -0700 | [diff] [blame] | 902 | spin_lock_init(&master->bus_lock_spinlock); |
| 903 | mutex_init(&master->bus_lock_mutex); |
| 904 | master->bus_lock_flag = 0; |
| 905 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 906 | /* register the device, then userspace will see it. |
| 907 | * registration fails if the bus ID is in use. |
| 908 | */ |
Kay Sievers | 35f74fc | 2009-01-06 10:44:37 -0800 | [diff] [blame] | 909 | dev_set_name(&master->dev, "spi%u", master->bus_num); |
Tony Jones | 49dce68 | 2007-10-16 01:27:48 -0700 | [diff] [blame] | 910 | status = device_add(&master->dev); |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 911 | if (status < 0) |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 912 | goto done; |
Kay Sievers | 35f74fc | 2009-01-06 10:44:37 -0800 | [diff] [blame] | 913 | dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev), |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 914 | dynamic ? " (dynamic)" : ""); |
| 915 | |
Linus Walleij | ffbbdd21 | 2012-02-22 10:05:38 +0100 | [diff] [blame] | 916 | /* If we're using a queued driver, start the queue */ |
| 917 | if (master->transfer) |
| 918 | dev_info(dev, "master is unqueued, this is deprecated\n"); |
| 919 | else { |
| 920 | status = spi_master_initialize_queue(master); |
| 921 | if (status) { |
| 922 | device_unregister(&master->dev); |
| 923 | goto done; |
| 924 | } |
| 925 | } |
| 926 | |
Feng Tang | 2b9603a | 2010-08-02 15:52:15 +0800 | [diff] [blame] | 927 | mutex_lock(&board_lock); |
| 928 | list_add_tail(&master->list, &spi_master_list); |
| 929 | list_for_each_entry(bi, &board_list, list) |
| 930 | spi_match_master_to_boardinfo(master, &bi->board_info); |
| 931 | mutex_unlock(&board_lock); |
| 932 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 933 | status = 0; |
Anatolij Gustschin | 12b15e8 | 2010-07-27 22:35:58 +0200 | [diff] [blame] | 934 | |
| 935 | /* Register devices from the device tree */ |
| 936 | of_register_spi_devices(master); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 937 | done: |
| 938 | return status; |
| 939 | } |
| 940 | EXPORT_SYMBOL_GPL(spi_register_master); |
| 941 | |
David Lamparter | 3486008 | 2010-08-30 23:54:17 +0200 | [diff] [blame] | 942 | static int __unregister(struct device *dev, void *null) |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 943 | { |
David Lamparter | 3486008 | 2010-08-30 23:54:17 +0200 | [diff] [blame] | 944 | spi_unregister_device(to_spi_device(dev)); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 945 | return 0; |
| 946 | } |
| 947 | |
| 948 | /** |
| 949 | * spi_unregister_master - unregister SPI master controller |
| 950 | * @master: the master being unregistered |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 951 | * Context: can sleep |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 952 | * |
| 953 | * This call is used only by SPI master controller drivers, which are the |
| 954 | * only ones directly touching chip registers. |
| 955 | * |
| 956 | * This must be called from context that can sleep. |
| 957 | */ |
| 958 | void spi_unregister_master(struct spi_master *master) |
| 959 | { |
Jeff Garzik | 89fc9a1 | 2006-12-06 20:35:35 -0800 | [diff] [blame] | 960 | int dummy; |
| 961 | |
Linus Walleij | ffbbdd21 | 2012-02-22 10:05:38 +0100 | [diff] [blame] | 962 | if (master->queued) { |
| 963 | if (spi_destroy_queue(master)) |
| 964 | dev_err(&master->dev, "queue remove failed\n"); |
| 965 | } |
| 966 | |
Feng Tang | 2b9603a | 2010-08-02 15:52:15 +0800 | [diff] [blame] | 967 | mutex_lock(&board_lock); |
| 968 | list_del(&master->list); |
| 969 | mutex_unlock(&board_lock); |
| 970 | |
Sebastian Andrzej Siewior | 97dbf37 | 2010-12-21 17:24:31 -0800 | [diff] [blame] | 971 | dummy = device_for_each_child(&master->dev, NULL, __unregister); |
Tony Jones | 49dce68 | 2007-10-16 01:27:48 -0700 | [diff] [blame] | 972 | device_unregister(&master->dev); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 973 | } |
| 974 | EXPORT_SYMBOL_GPL(spi_unregister_master); |
| 975 | |
Linus Walleij | ffbbdd21 | 2012-02-22 10:05:38 +0100 | [diff] [blame] | 976 | int spi_master_suspend(struct spi_master *master) |
| 977 | { |
| 978 | int ret; |
| 979 | |
| 980 | /* Basically no-ops for non-queued masters */ |
| 981 | if (!master->queued) |
| 982 | return 0; |
| 983 | |
| 984 | ret = spi_stop_queue(master); |
| 985 | if (ret) |
| 986 | dev_err(&master->dev, "queue stop failed\n"); |
| 987 | |
| 988 | return ret; |
| 989 | } |
| 990 | EXPORT_SYMBOL_GPL(spi_master_suspend); |
| 991 | |
| 992 | int spi_master_resume(struct spi_master *master) |
| 993 | { |
| 994 | int ret; |
| 995 | |
| 996 | if (!master->queued) |
| 997 | return 0; |
| 998 | |
| 999 | ret = spi_start_queue(master); |
| 1000 | if (ret) |
| 1001 | dev_err(&master->dev, "queue restart failed\n"); |
| 1002 | |
| 1003 | return ret; |
| 1004 | } |
| 1005 | EXPORT_SYMBOL_GPL(spi_master_resume); |
| 1006 | |
Dave Young | 5ed2c83 | 2008-01-22 15:14:18 +0800 | [diff] [blame] | 1007 | static int __spi_master_match(struct device *dev, void *data) |
| 1008 | { |
| 1009 | struct spi_master *m; |
| 1010 | u16 *bus_num = data; |
| 1011 | |
| 1012 | m = container_of(dev, struct spi_master, dev); |
| 1013 | return m->bus_num == *bus_num; |
| 1014 | } |
| 1015 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 1016 | /** |
| 1017 | * spi_busnum_to_master - look up master associated with bus_num |
| 1018 | * @bus_num: the master's bus number |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 1019 | * Context: can sleep |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 1020 | * |
| 1021 | * This call may be used with devices that are registered after |
| 1022 | * arch init time. It returns a refcounted pointer to the relevant |
| 1023 | * spi_master (which the caller must release), or NULL if there is |
| 1024 | * no such master registered. |
| 1025 | */ |
| 1026 | struct spi_master *spi_busnum_to_master(u16 bus_num) |
| 1027 | { |
Tony Jones | 49dce68 | 2007-10-16 01:27:48 -0700 | [diff] [blame] | 1028 | struct device *dev; |
Atsushi Nemoto | 1e9a51d | 2007-01-26 00:56:54 -0800 | [diff] [blame] | 1029 | struct spi_master *master = NULL; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 1030 | |
Greg Kroah-Hartman | 695794a | 2008-05-22 17:21:08 -0400 | [diff] [blame] | 1031 | dev = class_find_device(&spi_master_class, NULL, &bus_num, |
Dave Young | 5ed2c83 | 2008-01-22 15:14:18 +0800 | [diff] [blame] | 1032 | __spi_master_match); |
| 1033 | if (dev) |
| 1034 | master = container_of(dev, struct spi_master, dev); |
| 1035 | /* reference got in class_find_device */ |
Atsushi Nemoto | 1e9a51d | 2007-01-26 00:56:54 -0800 | [diff] [blame] | 1036 | return master; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 1037 | } |
| 1038 | EXPORT_SYMBOL_GPL(spi_busnum_to_master); |
| 1039 | |
| 1040 | |
| 1041 | /*-------------------------------------------------------------------------*/ |
| 1042 | |
David Brownell | 7d07719 | 2009-06-17 16:26:03 -0700 | [diff] [blame] | 1043 | /* Core methods for SPI master protocol drivers. Some of the |
| 1044 | * other core methods are currently defined as inline functions. |
| 1045 | */ |
| 1046 | |
| 1047 | /** |
| 1048 | * spi_setup - setup SPI mode and clock rate |
| 1049 | * @spi: the device whose settings are being modified |
| 1050 | * Context: can sleep, and no requests are queued to the device |
| 1051 | * |
| 1052 | * SPI protocol drivers may need to update the transfer mode if the |
| 1053 | * device doesn't work with its default. They may likewise need |
| 1054 | * to update clock rates or word sizes from initial values. This function |
| 1055 | * changes those settings, and must be called from a context that can sleep. |
| 1056 | * Except for SPI_CS_HIGH, which takes effect immediately, the changes take |
| 1057 | * effect the next time the device is selected and data is transferred to |
| 1058 | * or from it. When this function returns, the spi device is deselected. |
| 1059 | * |
| 1060 | * Note that this call will fail if the protocol driver specifies an option |
| 1061 | * that the underlying controller or its driver does not support. For |
| 1062 | * example, not all hardware supports wire transfers using nine bit words, |
| 1063 | * LSB-first wire encoding, or active-high chipselects. |
| 1064 | */ |
| 1065 | int spi_setup(struct spi_device *spi) |
| 1066 | { |
David Brownell | e7db06b | 2009-06-17 16:26:04 -0700 | [diff] [blame] | 1067 | unsigned bad_bits; |
David Brownell | 7d07719 | 2009-06-17 16:26:03 -0700 | [diff] [blame] | 1068 | int status; |
| 1069 | |
David Brownell | e7db06b | 2009-06-17 16:26:04 -0700 | [diff] [blame] | 1070 | /* help drivers fail *cleanly* when they need options |
| 1071 | * that aren't supported with their current master |
| 1072 | */ |
| 1073 | bad_bits = spi->mode & ~spi->master->mode_bits; |
| 1074 | if (bad_bits) { |
Linus Walleij | eb288a1 | 2010-10-21 21:06:44 +0200 | [diff] [blame] | 1075 | dev_err(&spi->dev, "setup: unsupported mode bits %x\n", |
David Brownell | e7db06b | 2009-06-17 16:26:04 -0700 | [diff] [blame] | 1076 | bad_bits); |
| 1077 | return -EINVAL; |
| 1078 | } |
| 1079 | |
David Brownell | 7d07719 | 2009-06-17 16:26:03 -0700 | [diff] [blame] | 1080 | if (!spi->bits_per_word) |
| 1081 | spi->bits_per_word = 8; |
| 1082 | |
| 1083 | status = spi->master->setup(spi); |
| 1084 | |
| 1085 | dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s" |
| 1086 | "%u bits/w, %u Hz max --> %d\n", |
| 1087 | (int) (spi->mode & (SPI_CPOL | SPI_CPHA)), |
| 1088 | (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "", |
| 1089 | (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "", |
| 1090 | (spi->mode & SPI_3WIRE) ? "3wire, " : "", |
| 1091 | (spi->mode & SPI_LOOP) ? "loopback, " : "", |
| 1092 | spi->bits_per_word, spi->max_speed_hz, |
| 1093 | status); |
| 1094 | |
| 1095 | return status; |
| 1096 | } |
| 1097 | EXPORT_SYMBOL_GPL(spi_setup); |
| 1098 | |
Ernst Schwab | cf32b71 | 2010-06-28 17:49:29 -0700 | [diff] [blame] | 1099 | static int __spi_async(struct spi_device *spi, struct spi_message *message) |
| 1100 | { |
| 1101 | struct spi_master *master = spi->master; |
| 1102 | |
| 1103 | /* Half-duplex links include original MicroWire, and ones with |
| 1104 | * only one data pin like SPI_3WIRE (switches direction) or where |
| 1105 | * either MOSI or MISO is missing. They can also be caused by |
| 1106 | * software limitations. |
| 1107 | */ |
| 1108 | if ((master->flags & SPI_MASTER_HALF_DUPLEX) |
| 1109 | || (spi->mode & SPI_3WIRE)) { |
| 1110 | struct spi_transfer *xfer; |
| 1111 | unsigned flags = master->flags; |
| 1112 | |
| 1113 | list_for_each_entry(xfer, &message->transfers, transfer_list) { |
| 1114 | if (xfer->rx_buf && xfer->tx_buf) |
| 1115 | return -EINVAL; |
| 1116 | if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf) |
| 1117 | return -EINVAL; |
| 1118 | if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf) |
| 1119 | return -EINVAL; |
| 1120 | } |
| 1121 | } |
| 1122 | |
| 1123 | message->spi = spi; |
| 1124 | message->status = -EINPROGRESS; |
| 1125 | return master->transfer(spi, message); |
| 1126 | } |
| 1127 | |
David Brownell | 568d069 | 2009-09-22 16:46:18 -0700 | [diff] [blame] | 1128 | /** |
| 1129 | * spi_async - asynchronous SPI transfer |
| 1130 | * @spi: device with which data will be exchanged |
| 1131 | * @message: describes the data transfers, including completion callback |
| 1132 | * Context: any (irqs may be blocked, etc) |
| 1133 | * |
| 1134 | * This call may be used in_irq and other contexts which can't sleep, |
| 1135 | * as well as from task contexts which can sleep. |
| 1136 | * |
| 1137 | * The completion callback is invoked in a context which can't sleep. |
| 1138 | * Before that invocation, the value of message->status is undefined. |
| 1139 | * When the callback is issued, message->status holds either zero (to |
| 1140 | * indicate complete success) or a negative error code. After that |
| 1141 | * callback returns, the driver which issued the transfer request may |
| 1142 | * deallocate the associated memory; it's no longer in use by any SPI |
| 1143 | * core or controller driver code. |
| 1144 | * |
| 1145 | * Note that although all messages to a spi_device are handled in |
| 1146 | * FIFO order, messages may go to different devices in other orders. |
| 1147 | * Some device might be higher priority, or have various "hard" access |
| 1148 | * time requirements, for example. |
| 1149 | * |
| 1150 | * On detection of any fault during the transfer, processing of |
| 1151 | * the entire message is aborted, and the device is deselected. |
| 1152 | * Until returning from the associated message completion callback, |
| 1153 | * no other spi_message queued to that device will be processed. |
| 1154 | * (This rule applies equally to all the synchronous transfer calls, |
| 1155 | * which are wrappers around this core asynchronous primitive.) |
| 1156 | */ |
| 1157 | int spi_async(struct spi_device *spi, struct spi_message *message) |
| 1158 | { |
| 1159 | struct spi_master *master = spi->master; |
Ernst Schwab | cf32b71 | 2010-06-28 17:49:29 -0700 | [diff] [blame] | 1160 | int ret; |
| 1161 | unsigned long flags; |
David Brownell | 568d069 | 2009-09-22 16:46:18 -0700 | [diff] [blame] | 1162 | |
Ernst Schwab | cf32b71 | 2010-06-28 17:49:29 -0700 | [diff] [blame] | 1163 | spin_lock_irqsave(&master->bus_lock_spinlock, flags); |
David Brownell | 568d069 | 2009-09-22 16:46:18 -0700 | [diff] [blame] | 1164 | |
Ernst Schwab | cf32b71 | 2010-06-28 17:49:29 -0700 | [diff] [blame] | 1165 | if (master->bus_lock_flag) |
| 1166 | ret = -EBUSY; |
| 1167 | else |
| 1168 | ret = __spi_async(spi, message); |
David Brownell | 568d069 | 2009-09-22 16:46:18 -0700 | [diff] [blame] | 1169 | |
Ernst Schwab | cf32b71 | 2010-06-28 17:49:29 -0700 | [diff] [blame] | 1170 | spin_unlock_irqrestore(&master->bus_lock_spinlock, flags); |
| 1171 | |
| 1172 | return ret; |
David Brownell | 568d069 | 2009-09-22 16:46:18 -0700 | [diff] [blame] | 1173 | } |
| 1174 | EXPORT_SYMBOL_GPL(spi_async); |
| 1175 | |
Ernst Schwab | cf32b71 | 2010-06-28 17:49:29 -0700 | [diff] [blame] | 1176 | /** |
| 1177 | * spi_async_locked - version of spi_async with exclusive bus usage |
| 1178 | * @spi: device with which data will be exchanged |
| 1179 | * @message: describes the data transfers, including completion callback |
| 1180 | * Context: any (irqs may be blocked, etc) |
| 1181 | * |
| 1182 | * This call may be used in_irq and other contexts which can't sleep, |
| 1183 | * as well as from task contexts which can sleep. |
| 1184 | * |
| 1185 | * The completion callback is invoked in a context which can't sleep. |
| 1186 | * Before that invocation, the value of message->status is undefined. |
| 1187 | * When the callback is issued, message->status holds either zero (to |
| 1188 | * indicate complete success) or a negative error code. After that |
| 1189 | * callback returns, the driver which issued the transfer request may |
| 1190 | * deallocate the associated memory; it's no longer in use by any SPI |
| 1191 | * core or controller driver code. |
| 1192 | * |
| 1193 | * Note that although all messages to a spi_device are handled in |
| 1194 | * FIFO order, messages may go to different devices in other orders. |
| 1195 | * Some device might be higher priority, or have various "hard" access |
| 1196 | * time requirements, for example. |
| 1197 | * |
| 1198 | * On detection of any fault during the transfer, processing of |
| 1199 | * the entire message is aborted, and the device is deselected. |
| 1200 | * Until returning from the associated message completion callback, |
| 1201 | * no other spi_message queued to that device will be processed. |
| 1202 | * (This rule applies equally to all the synchronous transfer calls, |
| 1203 | * which are wrappers around this core asynchronous primitive.) |
| 1204 | */ |
| 1205 | int spi_async_locked(struct spi_device *spi, struct spi_message *message) |
| 1206 | { |
| 1207 | struct spi_master *master = spi->master; |
| 1208 | int ret; |
| 1209 | unsigned long flags; |
| 1210 | |
| 1211 | spin_lock_irqsave(&master->bus_lock_spinlock, flags); |
| 1212 | |
| 1213 | ret = __spi_async(spi, message); |
| 1214 | |
| 1215 | spin_unlock_irqrestore(&master->bus_lock_spinlock, flags); |
| 1216 | |
| 1217 | return ret; |
| 1218 | |
| 1219 | } |
| 1220 | EXPORT_SYMBOL_GPL(spi_async_locked); |
| 1221 | |
David Brownell | 7d07719 | 2009-06-17 16:26:03 -0700 | [diff] [blame] | 1222 | |
| 1223 | /*-------------------------------------------------------------------------*/ |
| 1224 | |
| 1225 | /* Utility methods for SPI master protocol drivers, layered on |
| 1226 | * top of the core. Some other utility methods are defined as |
| 1227 | * inline functions. |
| 1228 | */ |
| 1229 | |
Andrew Morton | 5d870c8 | 2006-01-11 11:23:49 -0800 | [diff] [blame] | 1230 | static void spi_complete(void *arg) |
| 1231 | { |
| 1232 | complete(arg); |
| 1233 | } |
| 1234 | |
Ernst Schwab | cf32b71 | 2010-06-28 17:49:29 -0700 | [diff] [blame] | 1235 | static int __spi_sync(struct spi_device *spi, struct spi_message *message, |
| 1236 | int bus_locked) |
| 1237 | { |
| 1238 | DECLARE_COMPLETION_ONSTACK(done); |
| 1239 | int status; |
| 1240 | struct spi_master *master = spi->master; |
| 1241 | |
| 1242 | message->complete = spi_complete; |
| 1243 | message->context = &done; |
| 1244 | |
| 1245 | if (!bus_locked) |
| 1246 | mutex_lock(&master->bus_lock_mutex); |
| 1247 | |
| 1248 | status = spi_async_locked(spi, message); |
| 1249 | |
| 1250 | if (!bus_locked) |
| 1251 | mutex_unlock(&master->bus_lock_mutex); |
| 1252 | |
| 1253 | if (status == 0) { |
| 1254 | wait_for_completion(&done); |
| 1255 | status = message->status; |
| 1256 | } |
| 1257 | message->context = NULL; |
| 1258 | return status; |
| 1259 | } |
| 1260 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 1261 | /** |
| 1262 | * spi_sync - blocking/synchronous SPI data transfers |
| 1263 | * @spi: device with which data will be exchanged |
| 1264 | * @message: describes the data transfers |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 1265 | * Context: can sleep |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 1266 | * |
| 1267 | * This call may only be used from a context that may sleep. The sleep |
| 1268 | * is non-interruptible, and has no timeout. Low-overhead controller |
| 1269 | * drivers may DMA directly into and out of the message buffers. |
| 1270 | * |
| 1271 | * Note that the SPI device's chip select is active during the message, |
| 1272 | * and then is normally disabled between messages. Drivers for some |
| 1273 | * frequently-used devices may want to minimize costs of selecting a chip, |
| 1274 | * by leaving it selected in anticipation that the next message will go |
| 1275 | * to the same chip. (That may increase power usage.) |
| 1276 | * |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 1277 | * Also, the caller is guaranteeing that the memory associated with the |
| 1278 | * message will not be freed before this call returns. |
| 1279 | * |
Marc Pignat | 9b938b7 | 2007-12-04 23:45:10 -0800 | [diff] [blame] | 1280 | * It returns zero on success, else a negative error code. |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 1281 | */ |
| 1282 | int spi_sync(struct spi_device *spi, struct spi_message *message) |
| 1283 | { |
Ernst Schwab | cf32b71 | 2010-06-28 17:49:29 -0700 | [diff] [blame] | 1284 | return __spi_sync(spi, message, 0); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 1285 | } |
| 1286 | EXPORT_SYMBOL_GPL(spi_sync); |
| 1287 | |
Ernst Schwab | cf32b71 | 2010-06-28 17:49:29 -0700 | [diff] [blame] | 1288 | /** |
| 1289 | * spi_sync_locked - version of spi_sync with exclusive bus usage |
| 1290 | * @spi: device with which data will be exchanged |
| 1291 | * @message: describes the data transfers |
| 1292 | * Context: can sleep |
| 1293 | * |
| 1294 | * This call may only be used from a context that may sleep. The sleep |
| 1295 | * is non-interruptible, and has no timeout. Low-overhead controller |
| 1296 | * drivers may DMA directly into and out of the message buffers. |
| 1297 | * |
| 1298 | * This call should be used by drivers that require exclusive access to the |
Lucas De Marchi | 25985ed | 2011-03-30 22:57:33 -0300 | [diff] [blame] | 1299 | * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must |
Ernst Schwab | cf32b71 | 2010-06-28 17:49:29 -0700 | [diff] [blame] | 1300 | * be released by a spi_bus_unlock call when the exclusive access is over. |
| 1301 | * |
| 1302 | * It returns zero on success, else a negative error code. |
| 1303 | */ |
| 1304 | int spi_sync_locked(struct spi_device *spi, struct spi_message *message) |
| 1305 | { |
| 1306 | return __spi_sync(spi, message, 1); |
| 1307 | } |
| 1308 | EXPORT_SYMBOL_GPL(spi_sync_locked); |
| 1309 | |
| 1310 | /** |
| 1311 | * spi_bus_lock - obtain a lock for exclusive SPI bus usage |
| 1312 | * @master: SPI bus master that should be locked for exclusive bus access |
| 1313 | * Context: can sleep |
| 1314 | * |
| 1315 | * This call may only be used from a context that may sleep. The sleep |
| 1316 | * is non-interruptible, and has no timeout. |
| 1317 | * |
| 1318 | * This call should be used by drivers that require exclusive access to the |
| 1319 | * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the |
| 1320 | * exclusive access is over. Data transfer must be done by spi_sync_locked |
| 1321 | * and spi_async_locked calls when the SPI bus lock is held. |
| 1322 | * |
| 1323 | * It returns zero on success, else a negative error code. |
| 1324 | */ |
| 1325 | int spi_bus_lock(struct spi_master *master) |
| 1326 | { |
| 1327 | unsigned long flags; |
| 1328 | |
| 1329 | mutex_lock(&master->bus_lock_mutex); |
| 1330 | |
| 1331 | spin_lock_irqsave(&master->bus_lock_spinlock, flags); |
| 1332 | master->bus_lock_flag = 1; |
| 1333 | spin_unlock_irqrestore(&master->bus_lock_spinlock, flags); |
| 1334 | |
| 1335 | /* mutex remains locked until spi_bus_unlock is called */ |
| 1336 | |
| 1337 | return 0; |
| 1338 | } |
| 1339 | EXPORT_SYMBOL_GPL(spi_bus_lock); |
| 1340 | |
| 1341 | /** |
| 1342 | * spi_bus_unlock - release the lock for exclusive SPI bus usage |
| 1343 | * @master: SPI bus master that was locked for exclusive bus access |
| 1344 | * Context: can sleep |
| 1345 | * |
| 1346 | * This call may only be used from a context that may sleep. The sleep |
| 1347 | * is non-interruptible, and has no timeout. |
| 1348 | * |
| 1349 | * This call releases an SPI bus lock previously obtained by an spi_bus_lock |
| 1350 | * call. |
| 1351 | * |
| 1352 | * It returns zero on success, else a negative error code. |
| 1353 | */ |
| 1354 | int spi_bus_unlock(struct spi_master *master) |
| 1355 | { |
| 1356 | master->bus_lock_flag = 0; |
| 1357 | |
| 1358 | mutex_unlock(&master->bus_lock_mutex); |
| 1359 | |
| 1360 | return 0; |
| 1361 | } |
| 1362 | EXPORT_SYMBOL_GPL(spi_bus_unlock); |
| 1363 | |
David Brownell | a9948b6 | 2006-04-02 10:37:40 -0800 | [diff] [blame] | 1364 | /* portable code must never pass more than 32 bytes */ |
| 1365 | #define SPI_BUFSIZ max(32,SMP_CACHE_BYTES) |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 1366 | |
| 1367 | static u8 *buf; |
| 1368 | |
| 1369 | /** |
| 1370 | * spi_write_then_read - SPI synchronous write followed by read |
| 1371 | * @spi: device with which data will be exchanged |
| 1372 | * @txbuf: data to be written (need not be dma-safe) |
| 1373 | * @n_tx: size of txbuf, in bytes |
Jiri Pirko | 2757049 | 2009-06-17 16:26:06 -0700 | [diff] [blame] | 1374 | * @rxbuf: buffer into which data will be read (need not be dma-safe) |
| 1375 | * @n_rx: size of rxbuf, in bytes |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 1376 | * Context: can sleep |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 1377 | * |
| 1378 | * This performs a half duplex MicroWire style transaction with the |
| 1379 | * device, sending txbuf and then reading rxbuf. The return value |
| 1380 | * is zero for success, else a negative errno status code. |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 1381 | * This call may only be used from a context that may sleep. |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 1382 | * |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 1383 | * Parameters to this routine are always copied using a small buffer; |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 1384 | * portable code should never use this for more than 32 bytes. |
| 1385 | * Performance-sensitive or bulk transfer code should instead use |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 1386 | * spi_{async,sync}() calls with dma-safe buffers. |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 1387 | */ |
| 1388 | int spi_write_then_read(struct spi_device *spi, |
Mark Brown | 0c4a159 | 2011-05-11 00:09:30 +0200 | [diff] [blame] | 1389 | const void *txbuf, unsigned n_tx, |
| 1390 | void *rxbuf, unsigned n_rx) |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 1391 | { |
David Brownell | 068f407 | 2007-12-04 23:45:09 -0800 | [diff] [blame] | 1392 | static DEFINE_MUTEX(lock); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 1393 | |
| 1394 | int status; |
| 1395 | struct spi_message message; |
David Brownell | bdff549 | 2009-04-13 14:39:57 -0700 | [diff] [blame] | 1396 | struct spi_transfer x[2]; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 1397 | u8 *local_buf; |
| 1398 | |
| 1399 | /* Use preallocated DMA-safe buffer. We can't avoid copying here, |
| 1400 | * (as a pure convenience thing), but we can keep heap costs |
| 1401 | * out of the hot path ... |
| 1402 | */ |
| 1403 | if ((n_tx + n_rx) > SPI_BUFSIZ) |
| 1404 | return -EINVAL; |
| 1405 | |
Vitaly Wool | 8275c64 | 2006-01-08 13:34:28 -0800 | [diff] [blame] | 1406 | spi_message_init(&message); |
David Brownell | bdff549 | 2009-04-13 14:39:57 -0700 | [diff] [blame] | 1407 | memset(x, 0, sizeof x); |
| 1408 | if (n_tx) { |
| 1409 | x[0].len = n_tx; |
| 1410 | spi_message_add_tail(&x[0], &message); |
| 1411 | } |
| 1412 | if (n_rx) { |
| 1413 | x[1].len = n_rx; |
| 1414 | spi_message_add_tail(&x[1], &message); |
| 1415 | } |
Vitaly Wool | 8275c64 | 2006-01-08 13:34:28 -0800 | [diff] [blame] | 1416 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 1417 | /* ... unless someone else is using the pre-allocated buffer */ |
David Brownell | 068f407 | 2007-12-04 23:45:09 -0800 | [diff] [blame] | 1418 | if (!mutex_trylock(&lock)) { |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 1419 | local_buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL); |
| 1420 | if (!local_buf) |
| 1421 | return -ENOMEM; |
| 1422 | } else |
| 1423 | local_buf = buf; |
| 1424 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 1425 | memcpy(local_buf, txbuf, n_tx); |
David Brownell | bdff549 | 2009-04-13 14:39:57 -0700 | [diff] [blame] | 1426 | x[0].tx_buf = local_buf; |
| 1427 | x[1].rx_buf = local_buf + n_tx; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 1428 | |
| 1429 | /* do the i/o */ |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 1430 | status = spi_sync(spi, &message); |
Marc Pignat | 9b938b7 | 2007-12-04 23:45:10 -0800 | [diff] [blame] | 1431 | if (status == 0) |
David Brownell | bdff549 | 2009-04-13 14:39:57 -0700 | [diff] [blame] | 1432 | memcpy(rxbuf, x[1].rx_buf, n_rx); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 1433 | |
David Brownell | bdff549 | 2009-04-13 14:39:57 -0700 | [diff] [blame] | 1434 | if (x[0].tx_buf == buf) |
David Brownell | 068f407 | 2007-12-04 23:45:09 -0800 | [diff] [blame] | 1435 | mutex_unlock(&lock); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 1436 | else |
| 1437 | kfree(local_buf); |
| 1438 | |
| 1439 | return status; |
| 1440 | } |
| 1441 | EXPORT_SYMBOL_GPL(spi_write_then_read); |
| 1442 | |
| 1443 | /*-------------------------------------------------------------------------*/ |
| 1444 | |
| 1445 | static int __init spi_init(void) |
| 1446 | { |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 1447 | int status; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 1448 | |
Christoph Lameter | e94b176 | 2006-12-06 20:33:17 -0800 | [diff] [blame] | 1449 | buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL); |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 1450 | if (!buf) { |
| 1451 | status = -ENOMEM; |
| 1452 | goto err0; |
| 1453 | } |
| 1454 | |
| 1455 | status = bus_register(&spi_bus_type); |
| 1456 | if (status < 0) |
| 1457 | goto err1; |
| 1458 | |
| 1459 | status = class_register(&spi_master_class); |
| 1460 | if (status < 0) |
| 1461 | goto err2; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 1462 | return 0; |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 1463 | |
| 1464 | err2: |
| 1465 | bus_unregister(&spi_bus_type); |
| 1466 | err1: |
| 1467 | kfree(buf); |
| 1468 | buf = NULL; |
| 1469 | err0: |
| 1470 | return status; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 1471 | } |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 1472 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 1473 | /* board_info is normally registered in arch_initcall(), |
| 1474 | * but even essential drivers wait till later |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 1475 | * |
| 1476 | * REVISIT only boardinfo really needs static linking. the rest (device and |
| 1477 | * driver registration) _could_ be dynamically linked (modular) ... costs |
| 1478 | * include needing to have boardinfo data structures be much more public. |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 1479 | */ |
David Brownell | 673c0c0 | 2008-10-15 22:02:46 -0700 | [diff] [blame] | 1480 | postcore_initcall(spi_init); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 1481 | |