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 | |
| 21 | #include <linux/autoconf.h> |
| 22 | #include <linux/kernel.h> |
| 23 | #include <linux/device.h> |
| 24 | #include <linux/init.h> |
| 25 | #include <linux/cache.h> |
| 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 | |
| 50 | return snprintf(buf, BUS_ID_SIZE + 1, "%s\n", spi->modalias); |
| 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 | |
| 66 | return strncmp(spi->modalias, drv->name, BUS_ID_SIZE) == 0; |
| 67 | } |
| 68 | |
| 69 | static int spi_uevent(struct device *dev, char **envp, int num_envp, |
| 70 | char *buffer, int buffer_size) |
| 71 | { |
| 72 | const struct spi_device *spi = to_spi_device(dev); |
| 73 | |
| 74 | envp[0] = buffer; |
| 75 | snprintf(buffer, buffer_size, "MODALIAS=%s", spi->modalias); |
| 76 | envp[1] = NULL; |
| 77 | return 0; |
| 78 | } |
| 79 | |
| 80 | #ifdef CONFIG_PM |
| 81 | |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 82 | /* |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 83 | * NOTE: the suspend() method for an spi_master controller driver |
| 84 | * should verify that all its child devices are marked as suspended; |
| 85 | * suspend requests delivered through sysfs power/state files don't |
| 86 | * enforce such constraints. |
| 87 | */ |
| 88 | static int spi_suspend(struct device *dev, pm_message_t message) |
| 89 | { |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 90 | int value; |
| 91 | struct spi_driver *drv = to_spi_driver(dev->driver); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 92 | |
Stephen Street | d2799f0 | 2006-02-20 18:27:56 -0800 | [diff] [blame] | 93 | if (!drv || !drv->suspend) |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 94 | return 0; |
| 95 | |
| 96 | /* suspend will stop irqs and dma; no more i/o */ |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 97 | value = drv->suspend(to_spi_device(dev), message); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 98 | if (value == 0) |
| 99 | dev->power.power_state = message; |
| 100 | return value; |
| 101 | } |
| 102 | |
| 103 | static int spi_resume(struct device *dev) |
| 104 | { |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 105 | int value; |
| 106 | struct spi_driver *drv = to_spi_driver(dev->driver); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 107 | |
Stephen Street | d2799f0 | 2006-02-20 18:27:56 -0800 | [diff] [blame] | 108 | if (!drv || !drv->resume) |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 109 | return 0; |
| 110 | |
| 111 | /* resume may restart the i/o queue */ |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 112 | value = drv->resume(to_spi_device(dev)); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 113 | if (value == 0) |
| 114 | dev->power.power_state = PMSG_ON; |
| 115 | return value; |
| 116 | } |
| 117 | |
| 118 | #else |
| 119 | #define spi_suspend NULL |
| 120 | #define spi_resume NULL |
| 121 | #endif |
| 122 | |
| 123 | struct bus_type spi_bus_type = { |
| 124 | .name = "spi", |
| 125 | .dev_attrs = spi_dev_attrs, |
| 126 | .match = spi_match_device, |
| 127 | .uevent = spi_uevent, |
| 128 | .suspend = spi_suspend, |
| 129 | .resume = spi_resume, |
| 130 | }; |
| 131 | EXPORT_SYMBOL_GPL(spi_bus_type); |
| 132 | |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 133 | |
| 134 | static int spi_drv_probe(struct device *dev) |
| 135 | { |
| 136 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); |
| 137 | |
| 138 | return sdrv->probe(to_spi_device(dev)); |
| 139 | } |
| 140 | |
| 141 | static int spi_drv_remove(struct device *dev) |
| 142 | { |
| 143 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); |
| 144 | |
| 145 | return sdrv->remove(to_spi_device(dev)); |
| 146 | } |
| 147 | |
| 148 | static void spi_drv_shutdown(struct device *dev) |
| 149 | { |
| 150 | const struct spi_driver *sdrv = to_spi_driver(dev->driver); |
| 151 | |
| 152 | sdrv->shutdown(to_spi_device(dev)); |
| 153 | } |
| 154 | |
| 155 | int spi_register_driver(struct spi_driver *sdrv) |
| 156 | { |
| 157 | sdrv->driver.bus = &spi_bus_type; |
| 158 | if (sdrv->probe) |
| 159 | sdrv->driver.probe = spi_drv_probe; |
| 160 | if (sdrv->remove) |
| 161 | sdrv->driver.remove = spi_drv_remove; |
| 162 | if (sdrv->shutdown) |
| 163 | sdrv->driver.shutdown = spi_drv_shutdown; |
| 164 | return driver_register(&sdrv->driver); |
| 165 | } |
| 166 | EXPORT_SYMBOL_GPL(spi_register_driver); |
| 167 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 168 | /*-------------------------------------------------------------------------*/ |
| 169 | |
| 170 | /* SPI devices should normally not be created by SPI device drivers; that |
| 171 | * would make them board-specific. Similarly with SPI master drivers. |
| 172 | * Device registration normally goes into like arch/.../mach.../board-YYY.c |
| 173 | * with other readonly (flashable) information about mainboard devices. |
| 174 | */ |
| 175 | |
| 176 | struct boardinfo { |
| 177 | struct list_head list; |
| 178 | unsigned n_board_info; |
| 179 | struct spi_board_info board_info[0]; |
| 180 | }; |
| 181 | |
| 182 | static LIST_HEAD(board_list); |
| 183 | static DECLARE_MUTEX(board_lock); |
| 184 | |
| 185 | |
| 186 | /* On typical mainboards, this is purely internal; and it's not needed |
| 187 | * after board init creates the hard-wired devices. Some development |
| 188 | * platforms may not be able to use spi_register_board_info though, and |
| 189 | * this is exported so that for example a USB or parport based adapter |
| 190 | * driver could add devices (which it would learn about out-of-band). |
| 191 | */ |
| 192 | struct spi_device *__init_or_module |
| 193 | spi_new_device(struct spi_master *master, struct spi_board_info *chip) |
| 194 | { |
| 195 | struct spi_device *proxy; |
Greg Kroah-Hartman | 07b2463 | 2007-02-07 21:34:08 -0800 | [diff] [blame] | 196 | struct device *dev = master->cdev.dev; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 197 | int status; |
| 198 | |
| 199 | /* NOTE: caller did any chip->bus_num checks necessary */ |
| 200 | |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 201 | if (!spi_master_get(master)) |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 202 | return NULL; |
| 203 | |
| 204 | proxy = kzalloc(sizeof *proxy, GFP_KERNEL); |
| 205 | if (!proxy) { |
| 206 | dev_err(dev, "can't alloc dev for cs%d\n", |
| 207 | chip->chip_select); |
| 208 | goto fail; |
| 209 | } |
| 210 | proxy->master = master; |
| 211 | proxy->chip_select = chip->chip_select; |
| 212 | proxy->max_speed_hz = chip->max_speed_hz; |
David Brownell | 980a01c | 2006-06-28 07:47:15 -0700 | [diff] [blame] | 213 | proxy->mode = chip->mode; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 214 | proxy->irq = chip->irq; |
| 215 | proxy->modalias = chip->modalias; |
| 216 | |
| 217 | snprintf(proxy->dev.bus_id, sizeof proxy->dev.bus_id, |
Greg Kroah-Hartman | 07b2463 | 2007-02-07 21:34:08 -0800 | [diff] [blame] | 218 | "%s.%u", master->cdev.class_id, |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 219 | chip->chip_select); |
| 220 | proxy->dev.parent = dev; |
| 221 | proxy->dev.bus = &spi_bus_type; |
| 222 | proxy->dev.platform_data = (void *) chip->platform_data; |
| 223 | proxy->controller_data = chip->controller_data; |
| 224 | proxy->controller_state = NULL; |
| 225 | proxy->dev.release = spidev_release; |
| 226 | |
| 227 | /* drivers may modify this default i/o setup */ |
| 228 | status = master->setup(proxy); |
| 229 | if (status < 0) { |
| 230 | dev_dbg(dev, "can't %s %s, status %d\n", |
| 231 | "setup", proxy->dev.bus_id, status); |
| 232 | goto fail; |
| 233 | } |
| 234 | |
| 235 | /* driver core catches callers that misbehave by defining |
| 236 | * devices that already exist. |
| 237 | */ |
| 238 | status = device_register(&proxy->dev); |
| 239 | if (status < 0) { |
| 240 | dev_dbg(dev, "can't %s %s, status %d\n", |
| 241 | "add", proxy->dev.bus_id, status); |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 242 | goto fail; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 243 | } |
| 244 | dev_dbg(dev, "registered child %s\n", proxy->dev.bus_id); |
| 245 | return proxy; |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 246 | |
| 247 | fail: |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 248 | spi_master_put(master); |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 249 | kfree(proxy); |
| 250 | return NULL; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 251 | } |
| 252 | EXPORT_SYMBOL_GPL(spi_new_device); |
| 253 | |
| 254 | /* |
| 255 | * Board-specific early init code calls this (probably during arch_initcall) |
| 256 | * with segments of the SPI device table. Any device nodes are created later, |
| 257 | * after the relevant parent SPI controller (bus_num) is defined. We keep |
| 258 | * this table of devices forever, so that reloading a controller driver will |
| 259 | * not make Linux forget about these hard-wired devices. |
| 260 | * |
| 261 | * Other code can also call this, e.g. a particular add-on board might provide |
| 262 | * SPI devices through its expansion connector, so code initializing that board |
| 263 | * would naturally declare its SPI devices. |
| 264 | * |
| 265 | * The board info passed can safely be __initdata ... but be careful of |
| 266 | * any embedded pointers (platform_data, etc), they're copied as-is. |
| 267 | */ |
| 268 | int __init |
| 269 | spi_register_board_info(struct spi_board_info const *info, unsigned n) |
| 270 | { |
| 271 | struct boardinfo *bi; |
| 272 | |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 273 | bi = kmalloc(sizeof(*bi) + n * sizeof *info, GFP_KERNEL); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 274 | if (!bi) |
| 275 | return -ENOMEM; |
| 276 | bi->n_board_info = n; |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 277 | memcpy(bi->board_info, info, n * sizeof *info); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 278 | |
| 279 | down(&board_lock); |
| 280 | list_add_tail(&bi->list, &board_list); |
| 281 | up(&board_lock); |
| 282 | return 0; |
| 283 | } |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 284 | |
| 285 | /* FIXME someone should add support for a __setup("spi", ...) that |
| 286 | * creates board info from kernel command lines |
| 287 | */ |
| 288 | |
| 289 | static void __init_or_module |
| 290 | scan_boardinfo(struct spi_master *master) |
| 291 | { |
| 292 | struct boardinfo *bi; |
Greg Kroah-Hartman | 07b2463 | 2007-02-07 21:34:08 -0800 | [diff] [blame] | 293 | struct device *dev = master->cdev.dev; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 294 | |
| 295 | down(&board_lock); |
| 296 | list_for_each_entry(bi, &board_list, list) { |
| 297 | struct spi_board_info *chip = bi->board_info; |
| 298 | unsigned n; |
| 299 | |
| 300 | for (n = bi->n_board_info; n > 0; n--, chip++) { |
| 301 | if (chip->bus_num != master->bus_num) |
| 302 | continue; |
| 303 | /* some controllers only have one chip, so they |
| 304 | * might not use chipselects. otherwise, the |
| 305 | * chipselects are numbered 0..max. |
| 306 | */ |
| 307 | if (chip->chip_select >= master->num_chipselect |
| 308 | && master->num_chipselect) { |
| 309 | dev_dbg(dev, "cs%d > max %d\n", |
| 310 | chip->chip_select, |
| 311 | master->num_chipselect); |
| 312 | continue; |
| 313 | } |
| 314 | (void) spi_new_device(master, chip); |
| 315 | } |
| 316 | } |
| 317 | up(&board_lock); |
| 318 | } |
| 319 | |
| 320 | /*-------------------------------------------------------------------------*/ |
| 321 | |
Greg Kroah-Hartman | 07b2463 | 2007-02-07 21:34:08 -0800 | [diff] [blame] | 322 | static void spi_master_release(struct class_device *cdev) |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 323 | { |
| 324 | struct spi_master *master; |
| 325 | |
Greg Kroah-Hartman | 07b2463 | 2007-02-07 21:34:08 -0800 | [diff] [blame] | 326 | master = container_of(cdev, struct spi_master, cdev); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 327 | kfree(master); |
| 328 | } |
| 329 | |
| 330 | static struct class spi_master_class = { |
| 331 | .name = "spi_master", |
| 332 | .owner = THIS_MODULE, |
Greg Kroah-Hartman | 07b2463 | 2007-02-07 21:34:08 -0800 | [diff] [blame] | 333 | .release = spi_master_release, |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 334 | }; |
| 335 | |
| 336 | |
| 337 | /** |
| 338 | * spi_alloc_master - allocate SPI master controller |
| 339 | * @dev: the controller, possibly using the platform_bus |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 340 | * @size: how much driver-private data to preallocate; the pointer to this |
dmitry pervushin | ba1a051 | 2006-05-20 15:00:14 -0700 | [diff] [blame] | 341 | * memory is in the class_data field of the returned class_device, |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 342 | * accessible with spi_master_get_devdata(). |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 343 | * |
| 344 | * This call is used only by SPI master controller drivers, which are the |
| 345 | * only ones directly touching chip registers. It's how they allocate |
dmitry pervushin | ba1a051 | 2006-05-20 15:00:14 -0700 | [diff] [blame] | 346 | * an spi_master structure, prior to calling spi_register_master(). |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 347 | * |
| 348 | * This must be called from context that can sleep. It returns the SPI |
| 349 | * master structure on success, else NULL. |
| 350 | * |
| 351 | * The caller is responsible for assigning the bus number and initializing |
dmitry pervushin | ba1a051 | 2006-05-20 15:00:14 -0700 | [diff] [blame] | 352 | * the master's methods before calling spi_register_master(); and (after errors |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 353 | * adding the device) calling spi_master_put() to prevent a memory leak. |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 354 | */ |
| 355 | struct spi_master * __init_or_module |
| 356 | spi_alloc_master(struct device *dev, unsigned size) |
| 357 | { |
| 358 | struct spi_master *master; |
| 359 | |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 360 | if (!dev) |
| 361 | return NULL; |
| 362 | |
Christoph Lameter | e94b176 | 2006-12-06 20:33:17 -0800 | [diff] [blame] | 363 | master = kzalloc(size + sizeof *master, GFP_KERNEL); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 364 | if (!master) |
| 365 | return NULL; |
| 366 | |
Greg Kroah-Hartman | 07b2463 | 2007-02-07 21:34:08 -0800 | [diff] [blame] | 367 | class_device_initialize(&master->cdev); |
| 368 | master->cdev.class = &spi_master_class; |
| 369 | master->cdev.dev = get_device(dev); |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 370 | spi_master_set_devdata(master, &master[1]); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 371 | |
| 372 | return master; |
| 373 | } |
| 374 | EXPORT_SYMBOL_GPL(spi_alloc_master); |
| 375 | |
| 376 | /** |
| 377 | * spi_register_master - register SPI master controller |
| 378 | * @master: initialized master, originally from spi_alloc_master() |
| 379 | * |
| 380 | * SPI master controllers connect to their drivers using some non-SPI bus, |
| 381 | * such as the platform bus. The final stage of probe() in that code |
| 382 | * includes calling spi_register_master() to hook up to this SPI bus glue. |
| 383 | * |
| 384 | * SPI controllers use board specific (often SOC specific) bus numbers, |
| 385 | * and board-specific addressing for SPI devices combines those numbers |
| 386 | * with chip select numbers. Since SPI does not directly support dynamic |
| 387 | * device identification, boards need configuration tables telling which |
| 388 | * chip is at which address. |
| 389 | * |
| 390 | * This must be called from context that can sleep. It returns zero on |
| 391 | * success, else a negative error code (dropping the master's refcount). |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 392 | * After a successful return, the caller is responsible for calling |
| 393 | * spi_unregister_master(). |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 394 | */ |
| 395 | int __init_or_module |
| 396 | spi_register_master(struct spi_master *master) |
| 397 | { |
David Brownell | a020ed7 | 2006-04-03 15:49:04 -0700 | [diff] [blame] | 398 | static atomic_t dyn_bus_id = ATOMIC_INIT((1<<16) - 1); |
Greg Kroah-Hartman | 07b2463 | 2007-02-07 21:34:08 -0800 | [diff] [blame] | 399 | struct device *dev = master->cdev.dev; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 400 | int status = -ENODEV; |
| 401 | int dynamic = 0; |
| 402 | |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 403 | if (!dev) |
| 404 | return -ENODEV; |
| 405 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 406 | /* convention: dynamically assigned bus IDs count down from the max */ |
David Brownell | a020ed7 | 2006-04-03 15:49:04 -0700 | [diff] [blame] | 407 | if (master->bus_num < 0) { |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 408 | master->bus_num = atomic_dec_return(&dyn_bus_id); |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 409 | dynamic = 1; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 410 | } |
| 411 | |
| 412 | /* register the device, then userspace will see it. |
| 413 | * registration fails if the bus ID is in use. |
| 414 | */ |
Greg Kroah-Hartman | 07b2463 | 2007-02-07 21:34:08 -0800 | [diff] [blame] | 415 | snprintf(master->cdev.class_id, sizeof master->cdev.class_id, |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 416 | "spi%u", master->bus_num); |
Greg Kroah-Hartman | 07b2463 | 2007-02-07 21:34:08 -0800 | [diff] [blame] | 417 | status = class_device_add(&master->cdev); |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 418 | if (status < 0) |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 419 | goto done; |
Greg Kroah-Hartman | 07b2463 | 2007-02-07 21:34:08 -0800 | [diff] [blame] | 420 | dev_dbg(dev, "registered master %s%s\n", master->cdev.class_id, |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 421 | dynamic ? " (dynamic)" : ""); |
| 422 | |
| 423 | /* populate children from any spi device tables */ |
| 424 | scan_boardinfo(master); |
| 425 | status = 0; |
| 426 | done: |
| 427 | return status; |
| 428 | } |
| 429 | EXPORT_SYMBOL_GPL(spi_register_master); |
| 430 | |
| 431 | |
| 432 | static int __unregister(struct device *dev, void *unused) |
| 433 | { |
| 434 | /* note: before about 2.6.14-rc1 this would corrupt memory: */ |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 435 | spi_unregister_device(to_spi_device(dev)); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 436 | return 0; |
| 437 | } |
| 438 | |
| 439 | /** |
| 440 | * spi_unregister_master - unregister SPI master controller |
| 441 | * @master: the master being unregistered |
| 442 | * |
| 443 | * This call is used only by SPI master controller drivers, which are the |
| 444 | * only ones directly touching chip registers. |
| 445 | * |
| 446 | * This must be called from context that can sleep. |
| 447 | */ |
| 448 | void spi_unregister_master(struct spi_master *master) |
| 449 | { |
Jeff Garzik | 89fc9a1 | 2006-12-06 20:35:35 -0800 | [diff] [blame] | 450 | int dummy; |
| 451 | |
Greg Kroah-Hartman | 07b2463 | 2007-02-07 21:34:08 -0800 | [diff] [blame] | 452 | dummy = device_for_each_child(master->cdev.dev, NULL, __unregister); |
| 453 | class_device_unregister(&master->cdev); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 454 | } |
| 455 | EXPORT_SYMBOL_GPL(spi_unregister_master); |
| 456 | |
| 457 | /** |
| 458 | * spi_busnum_to_master - look up master associated with bus_num |
| 459 | * @bus_num: the master's bus number |
| 460 | * |
| 461 | * This call may be used with devices that are registered after |
| 462 | * arch init time. It returns a refcounted pointer to the relevant |
| 463 | * spi_master (which the caller must release), or NULL if there is |
| 464 | * no such master registered. |
| 465 | */ |
| 466 | struct spi_master *spi_busnum_to_master(u16 bus_num) |
| 467 | { |
Atsushi Nemoto | 1e9a51d | 2007-01-26 00:56:54 -0800 | [diff] [blame] | 468 | struct class_device *cdev; |
| 469 | struct spi_master *master = NULL; |
| 470 | struct spi_master *m; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 471 | |
Atsushi Nemoto | 1e9a51d | 2007-01-26 00:56:54 -0800 | [diff] [blame] | 472 | down(&spi_master_class.sem); |
| 473 | list_for_each_entry(cdev, &spi_master_class.children, node) { |
Greg Kroah-Hartman | 07b2463 | 2007-02-07 21:34:08 -0800 | [diff] [blame] | 474 | m = container_of(cdev, struct spi_master, cdev); |
Atsushi Nemoto | 1e9a51d | 2007-01-26 00:56:54 -0800 | [diff] [blame] | 475 | if (m->bus_num == bus_num) { |
| 476 | master = spi_master_get(m); |
| 477 | break; |
| 478 | } |
| 479 | } |
| 480 | up(&spi_master_class.sem); |
| 481 | return master; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 482 | } |
| 483 | EXPORT_SYMBOL_GPL(spi_busnum_to_master); |
| 484 | |
| 485 | |
| 486 | /*-------------------------------------------------------------------------*/ |
| 487 | |
Andrew Morton | 5d870c8 | 2006-01-11 11:23:49 -0800 | [diff] [blame] | 488 | static void spi_complete(void *arg) |
| 489 | { |
| 490 | complete(arg); |
| 491 | } |
| 492 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 493 | /** |
| 494 | * spi_sync - blocking/synchronous SPI data transfers |
| 495 | * @spi: device with which data will be exchanged |
| 496 | * @message: describes the data transfers |
| 497 | * |
| 498 | * This call may only be used from a context that may sleep. The sleep |
| 499 | * is non-interruptible, and has no timeout. Low-overhead controller |
| 500 | * drivers may DMA directly into and out of the message buffers. |
| 501 | * |
| 502 | * Note that the SPI device's chip select is active during the message, |
| 503 | * and then is normally disabled between messages. Drivers for some |
| 504 | * frequently-used devices may want to minimize costs of selecting a chip, |
| 505 | * by leaving it selected in anticipation that the next message will go |
| 506 | * to the same chip. (That may increase power usage.) |
| 507 | * |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 508 | * Also, the caller is guaranteeing that the memory associated with the |
| 509 | * message will not be freed before this call returns. |
| 510 | * |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 511 | * The return value is a negative error code if the message could not be |
| 512 | * submitted, else zero. When the value is zero, then message->status is |
| 513 | * also defined: it's the completion code for the transfer, either zero |
| 514 | * or a negative error code from the controller driver. |
| 515 | */ |
| 516 | int spi_sync(struct spi_device *spi, struct spi_message *message) |
| 517 | { |
Ingo Molnar | 60be6b9 | 2006-07-03 00:25:26 -0700 | [diff] [blame] | 518 | DECLARE_COMPLETION_ONSTACK(done); |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 519 | int status; |
| 520 | |
Andrew Morton | 5d870c8 | 2006-01-11 11:23:49 -0800 | [diff] [blame] | 521 | message->complete = spi_complete; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 522 | message->context = &done; |
| 523 | status = spi_async(spi, message); |
| 524 | if (status == 0) |
| 525 | wait_for_completion(&done); |
| 526 | message->context = NULL; |
| 527 | return status; |
| 528 | } |
| 529 | EXPORT_SYMBOL_GPL(spi_sync); |
| 530 | |
David Brownell | a9948b6 | 2006-04-02 10:37:40 -0800 | [diff] [blame] | 531 | /* portable code must never pass more than 32 bytes */ |
| 532 | #define SPI_BUFSIZ max(32,SMP_CACHE_BYTES) |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 533 | |
| 534 | static u8 *buf; |
| 535 | |
| 536 | /** |
| 537 | * spi_write_then_read - SPI synchronous write followed by read |
| 538 | * @spi: device with which data will be exchanged |
| 539 | * @txbuf: data to be written (need not be dma-safe) |
| 540 | * @n_tx: size of txbuf, in bytes |
| 541 | * @rxbuf: buffer into which data will be read |
| 542 | * @n_rx: size of rxbuf, in bytes (need not be dma-safe) |
| 543 | * |
| 544 | * This performs a half duplex MicroWire style transaction with the |
| 545 | * device, sending txbuf and then reading rxbuf. The return value |
| 546 | * is zero for success, else a negative errno status code. |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 547 | * This call may only be used from a context that may sleep. |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 548 | * |
David Brownell | 0c86846 | 2006-01-08 13:34:25 -0800 | [diff] [blame] | 549 | * Parameters to this routine are always copied using a small buffer; |
| 550 | * performance-sensitive or bulk transfer code should instead use |
| 551 | * spi_{async,sync}() calls with dma-safe buffers. |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 552 | */ |
| 553 | int spi_write_then_read(struct spi_device *spi, |
| 554 | const u8 *txbuf, unsigned n_tx, |
| 555 | u8 *rxbuf, unsigned n_rx) |
| 556 | { |
| 557 | static DECLARE_MUTEX(lock); |
| 558 | |
| 559 | int status; |
| 560 | struct spi_message message; |
| 561 | struct spi_transfer x[2]; |
| 562 | u8 *local_buf; |
| 563 | |
| 564 | /* Use preallocated DMA-safe buffer. We can't avoid copying here, |
| 565 | * (as a pure convenience thing), but we can keep heap costs |
| 566 | * out of the hot path ... |
| 567 | */ |
| 568 | if ((n_tx + n_rx) > SPI_BUFSIZ) |
| 569 | return -EINVAL; |
| 570 | |
Vitaly Wool | 8275c64 | 2006-01-08 13:34:28 -0800 | [diff] [blame] | 571 | spi_message_init(&message); |
| 572 | memset(x, 0, sizeof x); |
| 573 | if (n_tx) { |
| 574 | x[0].len = n_tx; |
| 575 | spi_message_add_tail(&x[0], &message); |
| 576 | } |
| 577 | if (n_rx) { |
| 578 | x[1].len = n_rx; |
| 579 | spi_message_add_tail(&x[1], &message); |
| 580 | } |
| 581 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 582 | /* ... unless someone else is using the pre-allocated buffer */ |
| 583 | if (down_trylock(&lock)) { |
| 584 | local_buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL); |
| 585 | if (!local_buf) |
| 586 | return -ENOMEM; |
| 587 | } else |
| 588 | local_buf = buf; |
| 589 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 590 | memcpy(local_buf, txbuf, n_tx); |
| 591 | x[0].tx_buf = local_buf; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 592 | x[1].rx_buf = local_buf + n_tx; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 593 | |
| 594 | /* do the i/o */ |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 595 | status = spi_sync(spi, &message); |
| 596 | if (status == 0) { |
| 597 | memcpy(rxbuf, x[1].rx_buf, n_rx); |
| 598 | status = message.status; |
| 599 | } |
| 600 | |
| 601 | if (x[0].tx_buf == buf) |
| 602 | up(&lock); |
| 603 | else |
| 604 | kfree(local_buf); |
| 605 | |
| 606 | return status; |
| 607 | } |
| 608 | EXPORT_SYMBOL_GPL(spi_write_then_read); |
| 609 | |
| 610 | /*-------------------------------------------------------------------------*/ |
| 611 | |
| 612 | static int __init spi_init(void) |
| 613 | { |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 614 | int status; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 615 | |
Christoph Lameter | e94b176 | 2006-12-06 20:33:17 -0800 | [diff] [blame] | 616 | buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL); |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 617 | if (!buf) { |
| 618 | status = -ENOMEM; |
| 619 | goto err0; |
| 620 | } |
| 621 | |
| 622 | status = bus_register(&spi_bus_type); |
| 623 | if (status < 0) |
| 624 | goto err1; |
| 625 | |
| 626 | status = class_register(&spi_master_class); |
| 627 | if (status < 0) |
| 628 | goto err2; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 629 | return 0; |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 630 | |
| 631 | err2: |
| 632 | bus_unregister(&spi_bus_type); |
| 633 | err1: |
| 634 | kfree(buf); |
| 635 | buf = NULL; |
| 636 | err0: |
| 637 | return status; |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 638 | } |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 639 | |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 640 | /* board_info is normally registered in arch_initcall(), |
| 641 | * but even essential drivers wait till later |
David Brownell | b885244 | 2006-01-08 13:34:23 -0800 | [diff] [blame] | 642 | * |
| 643 | * REVISIT only boardinfo really needs static linking. the rest (device and |
| 644 | * driver registration) _could_ be dynamically linked (modular) ... costs |
| 645 | * include needing to have boardinfo data structures be much more public. |
David Brownell | 8ae12a0 | 2006-01-08 13:34:19 -0800 | [diff] [blame] | 646 | */ |
| 647 | subsys_initcall(spi_init); |
| 648 | |