David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 1 | /* |
| 2 | * spi.c - SPI init/core code |
| 3 | * |
| 4 | * Copyright (C) 2005 David Brownell |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License as published by |
| 8 | * the Free Software Foundation; either version 2 of the License, or |
| 9 | * (at your option) any later version. |
| 10 | * |
| 11 | * This program is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | * GNU General Public License for more details. |
| 15 | * |
| 16 | * You should have received a copy of the GNU General Public License |
| 17 | * along with this program; if not, write to the Free Software |
| 18 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
| 19 | */ |
| 20 | |
David 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> |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 26 | #include <linux/spi/spi.h> |
| 27 | |
| 28 | |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 29 | /* SPI bustype and spi_master class are registered after board init code |
| 30 | * provides the SPI device tables, ensuring that both are present by the |
| 31 | * time controller driver registration causes spi_devices to "enumerate". |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 32 | */ |
| 33 | static void spidev_release(struct device *dev) |
| 34 | { |
Hans-Peter Nilsson | 0ffa028 | 2007-02-12 00:52:45 -0800 | [diff] [blame] | 35 | struct spi_device *spi = to_spi_device(dev); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 36 | |
| 37 | /* spi masters may cleanup for released devices */ |
| 38 | if (spi->master->cleanup) |
| 39 | spi->master->cleanup(spi); |
| 40 | |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 41 | spi_master_put(spi->master); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 42 | kfree(dev); |
| 43 | } |
| 44 | |
| 45 | static ssize_t |
| 46 | modalias_show(struct device *dev, struct device_attribute *a, char *buf) |
| 47 | { |
| 48 | const struct spi_device *spi = to_spi_device(dev); |
| 49 | |
Kay Sievers | 35f74fc | 2009-01-06 10:44:37 -0800 | [diff] [blame] | 50 | return sprintf(buf, "%s\n", spi->modalias); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 51 | } |
| 52 | |
| 53 | static struct device_attribute spi_dev_attrs[] = { |
| 54 | __ATTR_RO(modalias), |
| 55 | __ATTR_NULL, |
| 56 | }; |
| 57 | |
| 58 | /* modalias support makes "modprobe $MODALIAS" new-style hotplug work, |
| 59 | * and the sysfs version makes coldplug work too. |
| 60 | */ |
| 61 | |
| 62 | static int spi_match_device(struct device *dev, struct device_driver *drv) |
| 63 | { |
| 64 | const struct spi_device *spi = to_spi_device(dev); |
| 65 | |
Kay Sievers | 35f74fc | 2009-01-06 10:44:37 -0800 | [diff] [blame] | 66 | return strcmp(spi->modalias, drv->name) == 0; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 67 | } |
| 68 | |
Kay Sievers | 7eff2e7 | 2007-08-14 15:15:12 +0200 | [diff] [blame] | 69 | static int spi_uevent(struct device *dev, struct kobj_uevent_env *env) |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 70 | { |
| 71 | const struct spi_device *spi = to_spi_device(dev); |
| 72 | |
Kay Sievers | 7eff2e7 | 2007-08-14 15:15:12 +0200 | [diff] [blame] | 73 | add_uevent_var(env, "MODALIAS=%s", spi->modalias); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 74 | return 0; |
| 75 | } |
| 76 | |
| 77 | #ifdef CONFIG_PM |
| 78 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 79 | static int spi_suspend(struct device *dev, pm_message_t message) |
| 80 | { |
David Brownell | 3c72426 | 2008-02-06 01:38:10 -0800 | [diff] [blame] | 81 | int value = 0; |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 82 | struct spi_driver *drv = to_spi_driver(dev->driver); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 83 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 84 | /* suspend will stop irqs and dma; no more i/o */ |
David Brownell | 3c72426 | 2008-02-06 01:38:10 -0800 | [diff] [blame] | 85 | if (drv) { |
| 86 | if (drv->suspend) |
| 87 | value = drv->suspend(to_spi_device(dev), message); |
| 88 | else |
| 89 | dev_dbg(dev, "... can't suspend\n"); |
| 90 | } |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 91 | return value; |
| 92 | } |
| 93 | |
| 94 | static int spi_resume(struct device *dev) |
| 95 | { |
David Brownell | 3c72426 | 2008-02-06 01:38:10 -0800 | [diff] [blame] | 96 | int value = 0; |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 97 | struct spi_driver *drv = to_spi_driver(dev->driver); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 98 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 99 | /* resume may restart the i/o queue */ |
David Brownell | 3c72426 | 2008-02-06 01:38:10 -0800 | [diff] [blame] | 100 | if (drv) { |
| 101 | if (drv->resume) |
| 102 | value = drv->resume(to_spi_device(dev)); |
| 103 | else |
| 104 | dev_dbg(dev, "... can't resume\n"); |
| 105 | } |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 106 | return value; |
| 107 | } |
| 108 | |
| 109 | #else |
| 110 | #define spi_suspend NULL |
| 111 | #define spi_resume NULL |
| 112 | #endif |
| 113 | |
| 114 | struct bus_type spi_bus_type = { |
| 115 | .name = "spi", |
| 116 | .dev_attrs = spi_dev_attrs, |
| 117 | .match = spi_match_device, |
| 118 | .uevent = spi_uevent, |
| 119 | .suspend = spi_suspend, |
| 120 | .resume = spi_resume, |
| 121 | }; |
| 122 | EXPORT_SYMBOL_GPL(spi_bus_type); |
| 123 | |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 124 | |
| 125 | static int spi_drv_probe(struct device *dev) |
| 126 | { |
| 127 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); |
| 128 | |
| 129 | return sdrv->probe(to_spi_device(dev)); |
| 130 | } |
| 131 | |
| 132 | static int spi_drv_remove(struct device *dev) |
| 133 | { |
| 134 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); |
| 135 | |
| 136 | return sdrv->remove(to_spi_device(dev)); |
| 137 | } |
| 138 | |
| 139 | static void spi_drv_shutdown(struct device *dev) |
| 140 | { |
| 141 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); |
| 142 | |
| 143 | sdrv->shutdown(to_spi_device(dev)); |
| 144 | } |
| 145 | |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 146 | /** |
| 147 | * spi_register_driver - register a SPI driver |
| 148 | * @sdrv: the driver to register |
| 149 | * Context: can sleep |
| 150 | */ |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 151 | int spi_register_driver(struct spi_driver *sdrv) |
| 152 | { |
| 153 | sdrv->driver.bus = &spi_bus_type; |
| 154 | if (sdrv->probe) |
| 155 | sdrv->driver.probe = spi_drv_probe; |
| 156 | if (sdrv->remove) |
| 157 | sdrv->driver.remove = spi_drv_remove; |
| 158 | if (sdrv->shutdown) |
| 159 | sdrv->driver.shutdown = spi_drv_shutdown; |
| 160 | return driver_register(&sdrv->driver); |
| 161 | } |
| 162 | EXPORT_SYMBOL_GPL(spi_register_driver); |
| 163 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 164 | /*-------------------------------------------------------------------------*/ |
| 165 | |
| 166 | /* SPI devices should normally not be created by SPI device drivers; that |
| 167 | * would make them board-specific. Similarly with SPI master drivers. |
| 168 | * Device registration normally goes into like arch/.../mach.../board-YYY.c |
| 169 | * with other readonly (flashable) information about mainboard devices. |
| 170 | */ |
| 171 | |
| 172 | struct boardinfo { |
| 173 | struct list_head list; |
| 174 | unsigned n_board_info; |
| 175 | struct spi_board_info board_info[0]; |
| 176 | }; |
| 177 | |
| 178 | static LIST_HEAD(board_list); |
Matthias Kaehlcke | 9404082 | 2007-07-17 04:04:16 -0700 | [diff] [blame] | 179 | static DEFINE_MUTEX(board_lock); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 180 | |
Grant Likely | dc87c98 | 2008-05-15 16:50:22 -0600 | [diff] [blame] | 181 | /** |
| 182 | * spi_alloc_device - Allocate a new SPI device |
| 183 | * @master: Controller to which device is connected |
| 184 | * Context: can sleep |
| 185 | * |
| 186 | * Allows a driver to allocate and initialize a spi_device without |
| 187 | * registering it immediately. This allows a driver to directly |
| 188 | * fill the spi_device with device parameters before calling |
| 189 | * spi_add_device() on it. |
| 190 | * |
| 191 | * Caller is responsible to call spi_add_device() on the returned |
| 192 | * spi_device structure to add it to the SPI master. If the caller |
| 193 | * needs to discard the spi_device without adding it, then it should |
| 194 | * call spi_dev_put() on it. |
| 195 | * |
| 196 | * Returns a pointer to the new device, or NULL. |
| 197 | */ |
| 198 | struct spi_device *spi_alloc_device(struct spi_master *master) |
| 199 | { |
| 200 | struct spi_device *spi; |
| 201 | struct device *dev = master->dev.parent; |
| 202 | |
| 203 | if (!spi_master_get(master)) |
| 204 | return NULL; |
| 205 | |
| 206 | spi = kzalloc(sizeof *spi, GFP_KERNEL); |
| 207 | if (!spi) { |
| 208 | dev_err(dev, "cannot alloc spi_device\n"); |
| 209 | spi_master_put(master); |
| 210 | return NULL; |
| 211 | } |
| 212 | |
| 213 | spi->master = master; |
| 214 | spi->dev.parent = dev; |
| 215 | spi->dev.bus = &spi_bus_type; |
| 216 | spi->dev.release = spidev_release; |
| 217 | device_initialize(&spi->dev); |
| 218 | return spi; |
| 219 | } |
| 220 | EXPORT_SYMBOL_GPL(spi_alloc_device); |
| 221 | |
| 222 | /** |
| 223 | * spi_add_device - Add spi_device allocated with spi_alloc_device |
| 224 | * @spi: spi_device to register |
| 225 | * |
| 226 | * Companion function to spi_alloc_device. Devices allocated with |
| 227 | * spi_alloc_device can be added onto the spi bus with this function. |
| 228 | * |
David Brownell | e48880e | 2008-08-15 00:40:44 -0700 | [diff] [blame] | 229 | * Returns 0 on success; negative errno on failure |
Grant Likely | dc87c98 | 2008-05-15 16:50:22 -0600 | [diff] [blame] | 230 | */ |
| 231 | int spi_add_device(struct spi_device *spi) |
| 232 | { |
David Brownell | e48880e | 2008-08-15 00:40:44 -0700 | [diff] [blame] | 233 | static DEFINE_MUTEX(spi_add_lock); |
Grant Likely | dc87c98 | 2008-05-15 16:50:22 -0600 | [diff] [blame] | 234 | struct device *dev = spi->master->dev.parent; |
| 235 | int status; |
| 236 | |
| 237 | /* Chipselects are numbered 0..max; validate. */ |
| 238 | if (spi->chip_select >= spi->master->num_chipselect) { |
| 239 | dev_err(dev, "cs%d >= max %d\n", |
| 240 | spi->chip_select, |
| 241 | spi->master->num_chipselect); |
| 242 | return -EINVAL; |
| 243 | } |
| 244 | |
| 245 | /* Set the bus ID string */ |
Kay Sievers | 35f74fc | 2009-01-06 10:44:37 -0800 | [diff] [blame] | 246 | dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev), |
Grant Likely | dc87c98 | 2008-05-15 16:50:22 -0600 | [diff] [blame] | 247 | spi->chip_select); |
| 248 | |
David Brownell | e48880e | 2008-08-15 00:40:44 -0700 | [diff] [blame] | 249 | |
| 250 | /* We need to make sure there's no other device with this |
| 251 | * chipselect **BEFORE** we call setup(), else we'll trash |
| 252 | * its configuration. Lock against concurrent add() calls. |
| 253 | */ |
| 254 | mutex_lock(&spi_add_lock); |
| 255 | |
Kay Sievers | 35f74fc | 2009-01-06 10:44:37 -0800 | [diff] [blame] | 256 | if (bus_find_device_by_name(&spi_bus_type, NULL, dev_name(&spi->dev)) |
David Brownell | e48880e | 2008-08-15 00:40:44 -0700 | [diff] [blame] | 257 | != NULL) { |
| 258 | dev_err(dev, "chipselect %d already in use\n", |
| 259 | spi->chip_select); |
| 260 | status = -EBUSY; |
| 261 | goto done; |
| 262 | } |
| 263 | |
| 264 | /* Drivers may modify this initial i/o setup, but will |
| 265 | * normally rely on the device being setup. Devices |
| 266 | * using SPI_CS_HIGH can't coexist well otherwise... |
| 267 | */ |
David Brownell | 7d07719 | 2009-06-17 16:26:03 -0700 | [diff] [blame] | 268 | status = spi_setup(spi); |
Grant Likely | dc87c98 | 2008-05-15 16:50:22 -0600 | [diff] [blame] | 269 | if (status < 0) { |
| 270 | dev_err(dev, "can't %s %s, status %d\n", |
Kay Sievers | 35f74fc | 2009-01-06 10:44:37 -0800 | [diff] [blame] | 271 | "setup", dev_name(&spi->dev), status); |
David Brownell | e48880e | 2008-08-15 00:40:44 -0700 | [diff] [blame] | 272 | goto done; |
Grant Likely | dc87c98 | 2008-05-15 16:50:22 -0600 | [diff] [blame] | 273 | } |
| 274 | |
David Brownell | e48880e | 2008-08-15 00:40:44 -0700 | [diff] [blame] | 275 | /* Device may be bound to an active driver when this returns */ |
Grant Likely | dc87c98 | 2008-05-15 16:50:22 -0600 | [diff] [blame] | 276 | status = device_add(&spi->dev); |
David Brownell | e48880e | 2008-08-15 00:40:44 -0700 | [diff] [blame] | 277 | if (status < 0) |
Grant Likely | dc87c98 | 2008-05-15 16:50:22 -0600 | [diff] [blame] | 278 | dev_err(dev, "can't %s %s, status %d\n", |
Kay Sievers | 35f74fc | 2009-01-06 10:44:37 -0800 | [diff] [blame] | 279 | "add", dev_name(&spi->dev), status); |
David Brownell | e48880e | 2008-08-15 00:40:44 -0700 | [diff] [blame] | 280 | else |
Kay Sievers | 35f74fc | 2009-01-06 10:44:37 -0800 | [diff] [blame] | 281 | dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev)); |
Grant Likely | dc87c98 | 2008-05-15 16:50:22 -0600 | [diff] [blame] | 282 | |
David Brownell | e48880e | 2008-08-15 00:40:44 -0700 | [diff] [blame] | 283 | done: |
| 284 | mutex_unlock(&spi_add_lock); |
| 285 | return status; |
Grant Likely | dc87c98 | 2008-05-15 16:50:22 -0600 | [diff] [blame] | 286 | } |
| 287 | EXPORT_SYMBOL_GPL(spi_add_device); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 288 | |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 289 | /** |
| 290 | * spi_new_device - instantiate one new SPI device |
| 291 | * @master: Controller to which device is connected |
| 292 | * @chip: Describes the SPI device |
| 293 | * Context: can sleep |
| 294 | * |
| 295 | * On typical mainboards, this is purely internal; and it's not needed |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 296 | * after board init creates the hard-wired devices. Some development |
| 297 | * platforms may not be able to use spi_register_board_info though, and |
| 298 | * this is exported so that for example a USB or parport based adapter |
| 299 | * driver could add devices (which it would learn about out-of-band). |
David Brownell | 082c8cb | 2007-07-31 00:39:45 -0700 | [diff] [blame] | 300 | * |
| 301 | * Returns the new device, or NULL. |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 302 | */ |
Adrian Bunk | e9d5a46 | 2007-03-26 21:32:23 -0800 | [diff] [blame] | 303 | struct spi_device *spi_new_device(struct spi_master *master, |
| 304 | struct spi_board_info *chip) |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 305 | { |
| 306 | struct spi_device *proxy; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 307 | int status; |
| 308 | |
David Brownell | 082c8cb | 2007-07-31 00:39:45 -0700 | [diff] [blame] | 309 | /* NOTE: caller did any chip->bus_num checks necessary. |
| 310 | * |
| 311 | * Also, unless we change the return value convention to use |
| 312 | * error-or-pointer (not NULL-or-pointer), troubleshootability |
| 313 | * suggests syslogged diagnostics are best here (ugh). |
| 314 | */ |
| 315 | |
Grant Likely | dc87c98 | 2008-05-15 16:50:22 -0600 | [diff] [blame] | 316 | proxy = spi_alloc_device(master); |
| 317 | if (!proxy) |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 318 | return NULL; |
| 319 | |
Grant Likely | 102eb97 | 2008-07-23 21:29:55 -0700 | [diff] [blame] | 320 | WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias)); |
| 321 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 322 | proxy->chip_select = chip->chip_select; |
| 323 | proxy->max_speed_hz = chip->max_speed_hz; |
David Brownell | 980a01c | 2006-06-28 07:47:15 -0700 | [diff] [blame] | 324 | proxy->mode = chip->mode; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 325 | proxy->irq = chip->irq; |
Grant Likely | 102eb97 | 2008-07-23 21:29:55 -0700 | [diff] [blame] | 326 | strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias)); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 327 | proxy->dev.platform_data = (void *) chip->platform_data; |
| 328 | proxy->controller_data = chip->controller_data; |
| 329 | proxy->controller_state = NULL; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 330 | |
Grant Likely | dc87c98 | 2008-05-15 16:50:22 -0600 | [diff] [blame] | 331 | status = spi_add_device(proxy); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 332 | if (status < 0) { |
Grant Likely | dc87c98 | 2008-05-15 16:50:22 -0600 | [diff] [blame] | 333 | spi_dev_put(proxy); |
| 334 | return NULL; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 335 | } |
| 336 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 337 | return proxy; |
| 338 | } |
| 339 | EXPORT_SYMBOL_GPL(spi_new_device); |
| 340 | |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 341 | /** |
| 342 | * spi_register_board_info - register SPI devices for a given board |
| 343 | * @info: array of chip descriptors |
| 344 | * @n: how many descriptors are provided |
| 345 | * Context: can sleep |
| 346 | * |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 347 | * Board-specific early init code calls this (probably during arch_initcall) |
| 348 | * with segments of the SPI device table. Any device nodes are created later, |
| 349 | * after the relevant parent SPI controller (bus_num) is defined. We keep |
| 350 | * this table of devices forever, so that reloading a controller driver will |
| 351 | * not make Linux forget about these hard-wired devices. |
| 352 | * |
| 353 | * Other code can also call this, e.g. a particular add-on board might provide |
| 354 | * SPI devices through its expansion connector, so code initializing that board |
| 355 | * would naturally declare its SPI devices. |
| 356 | * |
| 357 | * The board info passed can safely be __initdata ... but be careful of |
| 358 | * any embedded pointers (platform_data, etc), they're copied as-is. |
| 359 | */ |
| 360 | int __init |
| 361 | spi_register_board_info(struct spi_board_info const *info, unsigned n) |
| 362 | { |
| 363 | struct boardinfo *bi; |
| 364 | |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 365 | bi = kmalloc(sizeof(*bi) + n * sizeof *info, GFP_KERNEL); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 366 | if (!bi) |
| 367 | return -ENOMEM; |
| 368 | bi->n_board_info = n; |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 369 | memcpy(bi->board_info, info, n * sizeof *info); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 370 | |
Matthias Kaehlcke | 9404082 | 2007-07-17 04:04:16 -0700 | [diff] [blame] | 371 | mutex_lock(&board_lock); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 372 | list_add_tail(&bi->list, &board_list); |
Matthias Kaehlcke | 9404082 | 2007-07-17 04:04:16 -0700 | [diff] [blame] | 373 | mutex_unlock(&board_lock); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 374 | return 0; |
| 375 | } |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 376 | |
| 377 | /* FIXME someone should add support for a __setup("spi", ...) that |
| 378 | * creates board info from kernel command lines |
| 379 | */ |
| 380 | |
Adrian Bunk | 149a650 | 2007-07-21 04:37:52 -0700 | [diff] [blame] | 381 | static void scan_boardinfo(struct spi_master *master) |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 382 | { |
| 383 | struct boardinfo *bi; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 384 | |
Matthias Kaehlcke | 9404082 | 2007-07-17 04:04:16 -0700 | [diff] [blame] | 385 | mutex_lock(&board_lock); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 386 | list_for_each_entry(bi, &board_list, list) { |
| 387 | struct spi_board_info *chip = bi->board_info; |
| 388 | unsigned n; |
| 389 | |
| 390 | for (n = bi->n_board_info; n > 0; n--, chip++) { |
| 391 | if (chip->bus_num != master->bus_num) |
| 392 | continue; |
David Brownell | 082c8cb | 2007-07-31 00:39:45 -0700 | [diff] [blame] | 393 | /* NOTE: this relies on spi_new_device to |
| 394 | * issue diagnostics when given bogus inputs |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 395 | */ |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 396 | (void) spi_new_device(master, chip); |
| 397 | } |
| 398 | } |
Matthias Kaehlcke | 9404082 | 2007-07-17 04:04:16 -0700 | [diff] [blame] | 399 | mutex_unlock(&board_lock); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 400 | } |
| 401 | |
| 402 | /*-------------------------------------------------------------------------*/ |
| 403 | |
Tony Jones | 49dce68 | 2007-10-16 01:27:48 -0700 | [diff] [blame] | 404 | static void spi_master_release(struct device *dev) |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 405 | { |
| 406 | struct spi_master *master; |
| 407 | |
Tony Jones | 49dce68 | 2007-10-16 01:27:48 -0700 | [diff] [blame] | 408 | master = container_of(dev, struct spi_master, dev); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 409 | kfree(master); |
| 410 | } |
| 411 | |
| 412 | static struct class spi_master_class = { |
| 413 | .name = "spi_master", |
| 414 | .owner = THIS_MODULE, |
Tony Jones | 49dce68 | 2007-10-16 01:27:48 -0700 | [diff] [blame] | 415 | .dev_release = spi_master_release, |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 416 | }; |
| 417 | |
| 418 | |
| 419 | /** |
| 420 | * spi_alloc_master - allocate SPI master controller |
| 421 | * @dev: the controller, possibly using the platform_bus |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 422 | * @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] | 423 | * memory is in the driver_data field of the returned device, |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 424 | * accessible with spi_master_get_devdata(). |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 425 | * Context: can sleep |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 426 | * |
| 427 | * This call is used only by SPI master controller drivers, which are the |
| 428 | * only ones directly touching chip registers. It's how they allocate |
dmitry pervushin | ba1a051 | 2006-05-20 15:00:14 -0700 | [diff] [blame] | 429 | * an spi_master structure, prior to calling spi_register_master(). |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 430 | * |
| 431 | * This must be called from context that can sleep. It returns the SPI |
| 432 | * master structure on success, else NULL. |
| 433 | * |
| 434 | * The caller is responsible for assigning the bus number and initializing |
dmitry pervushin | ba1a051 | 2006-05-20 15:00:14 -0700 | [diff] [blame] | 435 | * the master's methods before calling spi_register_master(); and (after errors |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 436 | * adding the device) calling spi_master_put() to prevent a memory leak. |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 437 | */ |
Adrian Bunk | e9d5a46 | 2007-03-26 21:32:23 -0800 | [diff] [blame] | 438 | struct spi_master *spi_alloc_master(struct device *dev, unsigned size) |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 439 | { |
| 440 | struct spi_master *master; |
| 441 | |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 442 | if (!dev) |
| 443 | return NULL; |
| 444 | |
Christoph Lameter | e94b176 | 2006-12-06 20:33:17 -0800 | [diff] [blame] | 445 | master = kzalloc(size + sizeof *master, GFP_KERNEL); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 446 | if (!master) |
| 447 | return NULL; |
| 448 | |
Tony Jones | 49dce68 | 2007-10-16 01:27:48 -0700 | [diff] [blame] | 449 | device_initialize(&master->dev); |
| 450 | master->dev.class = &spi_master_class; |
| 451 | master->dev.parent = get_device(dev); |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 452 | spi_master_set_devdata(master, &master[1]); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 453 | |
| 454 | return master; |
| 455 | } |
| 456 | EXPORT_SYMBOL_GPL(spi_alloc_master); |
| 457 | |
| 458 | /** |
| 459 | * spi_register_master - register SPI master controller |
| 460 | * @master: initialized master, originally from spi_alloc_master() |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 461 | * Context: can sleep |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 462 | * |
| 463 | * SPI master controllers connect to their drivers using some non-SPI bus, |
| 464 | * such as the platform bus. The final stage of probe() in that code |
| 465 | * includes calling spi_register_master() to hook up to this SPI bus glue. |
| 466 | * |
| 467 | * SPI controllers use board specific (often SOC specific) bus numbers, |
| 468 | * and board-specific addressing for SPI devices combines those numbers |
| 469 | * with chip select numbers. Since SPI does not directly support dynamic |
| 470 | * device identification, boards need configuration tables telling which |
| 471 | * chip is at which address. |
| 472 | * |
| 473 | * This must be called from context that can sleep. It returns zero on |
| 474 | * success, else a negative error code (dropping the master's refcount). |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 475 | * After a successful return, the caller is responsible for calling |
| 476 | * spi_unregister_master(). |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 477 | */ |
Adrian Bunk | e9d5a46 | 2007-03-26 21:32:23 -0800 | [diff] [blame] | 478 | int spi_register_master(struct spi_master *master) |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 479 | { |
David Brownell | e44a45a | 2007-06-03 13:50:40 -0700 | [diff] [blame] | 480 | static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1); |
Tony Jones | 49dce68 | 2007-10-16 01:27:48 -0700 | [diff] [blame] | 481 | struct device *dev = master->dev.parent; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 482 | int status = -ENODEV; |
| 483 | int dynamic = 0; |
| 484 | |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 485 | if (!dev) |
| 486 | return -ENODEV; |
| 487 | |
David Brownell | 082c8cb | 2007-07-31 00:39:45 -0700 | [diff] [blame] | 488 | /* even if it's just one always-selected device, there must |
| 489 | * be at least one chipselect |
| 490 | */ |
| 491 | if (master->num_chipselect == 0) |
| 492 | return -EINVAL; |
| 493 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 494 | /* convention: dynamically assigned bus IDs count down from the max */ |
David Brownell | a020ed7 | 2006-04-03 15:49:04 -0700 | [diff] [blame] | 495 | if (master->bus_num < 0) { |
David Brownell | 082c8cb | 2007-07-31 00:39:45 -0700 | [diff] [blame] | 496 | /* FIXME switch to an IDR based scheme, something like |
| 497 | * I2C now uses, so we can't run out of "dynamic" IDs |
| 498 | */ |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 499 | master->bus_num = atomic_dec_return(&dyn_bus_id); |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 500 | dynamic = 1; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 501 | } |
| 502 | |
| 503 | /* register the device, then userspace will see it. |
| 504 | * registration fails if the bus ID is in use. |
| 505 | */ |
Kay Sievers | 35f74fc | 2009-01-06 10:44:37 -0800 | [diff] [blame] | 506 | dev_set_name(&master->dev, "spi%u", master->bus_num); |
Tony Jones | 49dce68 | 2007-10-16 01:27:48 -0700 | [diff] [blame] | 507 | status = device_add(&master->dev); |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 508 | if (status < 0) |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 509 | goto done; |
Kay Sievers | 35f74fc | 2009-01-06 10:44:37 -0800 | [diff] [blame] | 510 | dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev), |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 511 | dynamic ? " (dynamic)" : ""); |
| 512 | |
| 513 | /* populate children from any spi device tables */ |
| 514 | scan_boardinfo(master); |
| 515 | status = 0; |
| 516 | done: |
| 517 | return status; |
| 518 | } |
| 519 | EXPORT_SYMBOL_GPL(spi_register_master); |
| 520 | |
| 521 | |
Atsushi Nemoto | 350d007 | 2007-11-14 16:59:22 -0800 | [diff] [blame] | 522 | static int __unregister(struct device *dev, void *master_dev) |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 523 | { |
| 524 | /* note: before about 2.6.14-rc1 this would corrupt memory: */ |
Atsushi Nemoto | 350d007 | 2007-11-14 16:59:22 -0800 | [diff] [blame] | 525 | if (dev != master_dev) |
| 526 | spi_unregister_device(to_spi_device(dev)); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 527 | return 0; |
| 528 | } |
| 529 | |
| 530 | /** |
| 531 | * spi_unregister_master - unregister SPI master controller |
| 532 | * @master: the master being unregistered |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 533 | * Context: can sleep |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 534 | * |
| 535 | * This call is used only by SPI master controller drivers, which are the |
| 536 | * only ones directly touching chip registers. |
| 537 | * |
| 538 | * This must be called from context that can sleep. |
| 539 | */ |
| 540 | void spi_unregister_master(struct spi_master *master) |
| 541 | { |
Jeff Garzik | 89fc9a1 | 2006-12-06 20:35:35 -0800 | [diff] [blame] | 542 | int dummy; |
| 543 | |
Atsushi Nemoto | 350d007 | 2007-11-14 16:59:22 -0800 | [diff] [blame] | 544 | dummy = device_for_each_child(master->dev.parent, &master->dev, |
| 545 | __unregister); |
Tony Jones | 49dce68 | 2007-10-16 01:27:48 -0700 | [diff] [blame] | 546 | device_unregister(&master->dev); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 547 | } |
| 548 | EXPORT_SYMBOL_GPL(spi_unregister_master); |
| 549 | |
Dave Young | 5ed2c83 | 2008-01-22 15:14:18 +0800 | [diff] [blame] | 550 | static int __spi_master_match(struct device *dev, void *data) |
| 551 | { |
| 552 | struct spi_master *m; |
| 553 | u16 *bus_num = data; |
| 554 | |
| 555 | m = container_of(dev, struct spi_master, dev); |
| 556 | return m->bus_num == *bus_num; |
| 557 | } |
| 558 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 559 | /** |
| 560 | * spi_busnum_to_master - look up master associated with bus_num |
| 561 | * @bus_num: the master's bus number |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 562 | * Context: can sleep |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 563 | * |
| 564 | * This call may be used with devices that are registered after |
| 565 | * arch init time. It returns a refcounted pointer to the relevant |
| 566 | * spi_master (which the caller must release), or NULL if there is |
| 567 | * no such master registered. |
| 568 | */ |
| 569 | struct spi_master *spi_busnum_to_master(u16 bus_num) |
| 570 | { |
Tony Jones | 49dce68 | 2007-10-16 01:27:48 -0700 | [diff] [blame] | 571 | struct device *dev; |
Atsushi Nemoto | 1e9a51d | 2007-01-26 00:56:54 -0800 | [diff] [blame] | 572 | struct spi_master *master = NULL; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 573 | |
Greg Kroah-Hartman | 695794a | 2008-05-22 17:21:08 -0400 | [diff] [blame] | 574 | dev = class_find_device(&spi_master_class, NULL, &bus_num, |
Dave Young | 5ed2c83 | 2008-01-22 15:14:18 +0800 | [diff] [blame] | 575 | __spi_master_match); |
| 576 | if (dev) |
| 577 | master = container_of(dev, struct spi_master, dev); |
| 578 | /* reference got in class_find_device */ |
Atsushi Nemoto | 1e9a51d | 2007-01-26 00:56:54 -0800 | [diff] [blame] | 579 | return master; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 580 | } |
| 581 | EXPORT_SYMBOL_GPL(spi_busnum_to_master); |
| 582 | |
| 583 | |
| 584 | /*-------------------------------------------------------------------------*/ |
| 585 | |
David Brownell | 7d07719 | 2009-06-17 16:26:03 -0700 | [diff] [blame] | 586 | /* Core methods for SPI master protocol drivers. Some of the |
| 587 | * other core methods are currently defined as inline functions. |
| 588 | */ |
| 589 | |
| 590 | /** |
| 591 | * spi_setup - setup SPI mode and clock rate |
| 592 | * @spi: the device whose settings are being modified |
| 593 | * Context: can sleep, and no requests are queued to the device |
| 594 | * |
| 595 | * SPI protocol drivers may need to update the transfer mode if the |
| 596 | * device doesn't work with its default. They may likewise need |
| 597 | * to update clock rates or word sizes from initial values. This function |
| 598 | * changes those settings, and must be called from a context that can sleep. |
| 599 | * Except for SPI_CS_HIGH, which takes effect immediately, the changes take |
| 600 | * effect the next time the device is selected and data is transferred to |
| 601 | * or from it. When this function returns, the spi device is deselected. |
| 602 | * |
| 603 | * Note that this call will fail if the protocol driver specifies an option |
| 604 | * that the underlying controller or its driver does not support. For |
| 605 | * example, not all hardware supports wire transfers using nine bit words, |
| 606 | * LSB-first wire encoding, or active-high chipselects. |
| 607 | */ |
| 608 | int spi_setup(struct spi_device *spi) |
| 609 | { |
David Brownell | e7db06b | 2009-06-17 16:26:04 -0700 | [diff] [blame] | 610 | unsigned bad_bits; |
David Brownell | 7d07719 | 2009-06-17 16:26:03 -0700 | [diff] [blame] | 611 | int status; |
| 612 | |
David Brownell | e7db06b | 2009-06-17 16:26:04 -0700 | [diff] [blame] | 613 | /* help drivers fail *cleanly* when they need options |
| 614 | * that aren't supported with their current master |
| 615 | */ |
| 616 | bad_bits = spi->mode & ~spi->master->mode_bits; |
| 617 | if (bad_bits) { |
| 618 | dev_dbg(&spi->dev, "setup: unsupported mode bits %x\n", |
| 619 | bad_bits); |
| 620 | return -EINVAL; |
| 621 | } |
| 622 | |
David Brownell | 7d07719 | 2009-06-17 16:26:03 -0700 | [diff] [blame] | 623 | if (!spi->bits_per_word) |
| 624 | spi->bits_per_word = 8; |
| 625 | |
| 626 | status = spi->master->setup(spi); |
| 627 | |
| 628 | dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s" |
| 629 | "%u bits/w, %u Hz max --> %d\n", |
| 630 | (int) (spi->mode & (SPI_CPOL | SPI_CPHA)), |
| 631 | (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "", |
| 632 | (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "", |
| 633 | (spi->mode & SPI_3WIRE) ? "3wire, " : "", |
| 634 | (spi->mode & SPI_LOOP) ? "loopback, " : "", |
| 635 | spi->bits_per_word, spi->max_speed_hz, |
| 636 | status); |
| 637 | |
| 638 | return status; |
| 639 | } |
| 640 | EXPORT_SYMBOL_GPL(spi_setup); |
| 641 | |
| 642 | |
| 643 | /*-------------------------------------------------------------------------*/ |
| 644 | |
| 645 | /* Utility methods for SPI master protocol drivers, layered on |
| 646 | * top of the core. Some other utility methods are defined as |
| 647 | * inline functions. |
| 648 | */ |
| 649 | |
Andrew Morton | 5d870c8 | 2006-01-11 11:23:49 -0800 | [diff] [blame] | 650 | static void spi_complete(void *arg) |
| 651 | { |
| 652 | complete(arg); |
| 653 | } |
| 654 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 655 | /** |
| 656 | * spi_sync - blocking/synchronous SPI data transfers |
| 657 | * @spi: device with which data will be exchanged |
| 658 | * @message: describes the data transfers |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 659 | * Context: can sleep |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 660 | * |
| 661 | * This call may only be used from a context that may sleep. The sleep |
| 662 | * is non-interruptible, and has no timeout. Low-overhead controller |
| 663 | * drivers may DMA directly into and out of the message buffers. |
| 664 | * |
| 665 | * Note that the SPI device's chip select is active during the message, |
| 666 | * and then is normally disabled between messages. Drivers for some |
| 667 | * frequently-used devices may want to minimize costs of selecting a chip, |
| 668 | * by leaving it selected in anticipation that the next message will go |
| 669 | * to the same chip. (That may increase power usage.) |
| 670 | * |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 671 | * Also, the caller is guaranteeing that the memory associated with the |
| 672 | * message will not be freed before this call returns. |
| 673 | * |
Marc Pignat | 9b938b7 | 2007-12-04 23:45:10 -0800 | [diff] [blame] | 674 | * It returns zero on success, else a negative error code. |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 675 | */ |
| 676 | int spi_sync(struct spi_device *spi, struct spi_message *message) |
| 677 | { |
Ingo Molnar | 60be6b9 | 2006-07-03 00:25:26 -0700 | [diff] [blame] | 678 | DECLARE_COMPLETION_ONSTACK(done); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 679 | int status; |
| 680 | |
Andrew Morton | 5d870c8 | 2006-01-11 11:23:49 -0800 | [diff] [blame] | 681 | message->complete = spi_complete; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 682 | message->context = &done; |
| 683 | status = spi_async(spi, message); |
Marc Pignat | 9b938b7 | 2007-12-04 23:45:10 -0800 | [diff] [blame] | 684 | if (status == 0) { |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 685 | wait_for_completion(&done); |
Marc Pignat | 9b938b7 | 2007-12-04 23:45:10 -0800 | [diff] [blame] | 686 | status = message->status; |
| 687 | } |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 688 | message->context = NULL; |
| 689 | return status; |
| 690 | } |
| 691 | EXPORT_SYMBOL_GPL(spi_sync); |
| 692 | |
David Brownell | a9948b6 | 2006-04-02 10:37:40 -0800 | [diff] [blame] | 693 | /* portable code must never pass more than 32 bytes */ |
| 694 | #define SPI_BUFSIZ max(32,SMP_CACHE_BYTES) |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 695 | |
| 696 | static u8 *buf; |
| 697 | |
| 698 | /** |
| 699 | * spi_write_then_read - SPI synchronous write followed by read |
| 700 | * @spi: device with which data will be exchanged |
| 701 | * @txbuf: data to be written (need not be dma-safe) |
| 702 | * @n_tx: size of txbuf, in bytes |
Jiri Pirko | 2757049 | 2009-06-17 16:26:06 -0700 | [diff] [blame^] | 703 | * @rxbuf: buffer into which data will be read (need not be dma-safe) |
| 704 | * @n_rx: size of rxbuf, in bytes |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 705 | * Context: can sleep |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 706 | * |
| 707 | * This performs a half duplex MicroWire style transaction with the |
| 708 | * device, sending txbuf and then reading rxbuf. The return value |
| 709 | * is zero for success, else a negative errno status code. |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 710 | * This call may only be used from a context that may sleep. |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 711 | * |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 712 | * Parameters to this routine are always copied using a small buffer; |
David Brownell | 33e34dc | 2007-05-08 00:32:21 -0700 | [diff] [blame] | 713 | * portable code should never use this for more than 32 bytes. |
| 714 | * Performance-sensitive or bulk transfer code should instead use |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 715 | * spi_{async,sync}() calls with dma-safe buffers. |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 716 | */ |
| 717 | int spi_write_then_read(struct spi_device *spi, |
| 718 | const u8 *txbuf, unsigned n_tx, |
| 719 | u8 *rxbuf, unsigned n_rx) |
| 720 | { |
David Brownell | 068f407 | 2007-12-04 23:45:09 -0800 | [diff] [blame] | 721 | static DEFINE_MUTEX(lock); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 722 | |
| 723 | int status; |
| 724 | struct spi_message message; |
David Brownell | bdff549 | 2009-04-13 14:39:57 -0700 | [diff] [blame] | 725 | struct spi_transfer x[2]; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 726 | u8 *local_buf; |
| 727 | |
| 728 | /* Use preallocated DMA-safe buffer. We can't avoid copying here, |
| 729 | * (as a pure convenience thing), but we can keep heap costs |
| 730 | * out of the hot path ... |
| 731 | */ |
| 732 | if ((n_tx + n_rx) > SPI_BUFSIZ) |
| 733 | return -EINVAL; |
| 734 | |
Vitaly Wool | 8275c64 | 2006-01-08 13:34:28 -0800 | [diff] [blame] | 735 | spi_message_init(&message); |
David Brownell | bdff549 | 2009-04-13 14:39:57 -0700 | [diff] [blame] | 736 | memset(x, 0, sizeof x); |
| 737 | if (n_tx) { |
| 738 | x[0].len = n_tx; |
| 739 | spi_message_add_tail(&x[0], &message); |
| 740 | } |
| 741 | if (n_rx) { |
| 742 | x[1].len = n_rx; |
| 743 | spi_message_add_tail(&x[1], &message); |
| 744 | } |
Vitaly Wool | 8275c64 | 2006-01-08 13:34:28 -0800 | [diff] [blame] | 745 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 746 | /* ... unless someone else is using the pre-allocated buffer */ |
David Brownell | 068f407 | 2007-12-04 23:45:09 -0800 | [diff] [blame] | 747 | if (!mutex_trylock(&lock)) { |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 748 | local_buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL); |
| 749 | if (!local_buf) |
| 750 | return -ENOMEM; |
| 751 | } else |
| 752 | local_buf = buf; |
| 753 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 754 | memcpy(local_buf, txbuf, n_tx); |
David Brownell | bdff549 | 2009-04-13 14:39:57 -0700 | [diff] [blame] | 755 | x[0].tx_buf = local_buf; |
| 756 | x[1].rx_buf = local_buf + n_tx; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 757 | |
| 758 | /* do the i/o */ |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 759 | status = spi_sync(spi, &message); |
Marc Pignat | 9b938b7 | 2007-12-04 23:45:10 -0800 | [diff] [blame] | 760 | if (status == 0) |
David Brownell | bdff549 | 2009-04-13 14:39:57 -0700 | [diff] [blame] | 761 | memcpy(rxbuf, x[1].rx_buf, n_rx); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 762 | |
David Brownell | bdff549 | 2009-04-13 14:39:57 -0700 | [diff] [blame] | 763 | if (x[0].tx_buf == buf) |
David Brownell | 068f407 | 2007-12-04 23:45:09 -0800 | [diff] [blame] | 764 | mutex_unlock(&lock); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 765 | else |
| 766 | kfree(local_buf); |
| 767 | |
| 768 | return status; |
| 769 | } |
| 770 | EXPORT_SYMBOL_GPL(spi_write_then_read); |
| 771 | |
| 772 | /*-------------------------------------------------------------------------*/ |
| 773 | |
| 774 | static int __init spi_init(void) |
| 775 | { |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 776 | int status; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 777 | |
Christoph Lameter | e94b176 | 2006-12-06 20:33:17 -0800 | [diff] [blame] | 778 | buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL); |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 779 | if (!buf) { |
| 780 | status = -ENOMEM; |
| 781 | goto err0; |
| 782 | } |
| 783 | |
| 784 | status = bus_register(&spi_bus_type); |
| 785 | if (status < 0) |
| 786 | goto err1; |
| 787 | |
| 788 | status = class_register(&spi_master_class); |
| 789 | if (status < 0) |
| 790 | goto err2; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 791 | return 0; |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 792 | |
| 793 | err2: |
| 794 | bus_unregister(&spi_bus_type); |
| 795 | err1: |
| 796 | kfree(buf); |
| 797 | buf = NULL; |
| 798 | err0: |
| 799 | return status; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 800 | } |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 801 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 802 | /* board_info is normally registered in arch_initcall(), |
| 803 | * but even essential drivers wait till later |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 804 | * |
| 805 | * REVISIT only boardinfo really needs static linking. the rest (device and |
| 806 | * driver registration) _could_ be dynamically linked (modular) ... costs |
| 807 | * include needing to have boardinfo data structures be much more public. |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 808 | */ |
David Brownell | 673c0c0 | 2008-10-15 22:02:46 -0700 | [diff] [blame] | 809 | postcore_initcall(spi_init); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 810 | |