Mark Brown | 502a0106 | 2009-07-27 14:46:12 +0100 | [diff] [blame] | 1 | /* |
| 2 | * Watchdog driver for the wm831x PMICs |
| 3 | * |
| 4 | * Copyright (C) 2009 Wolfson Microelectronics |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU General Public License |
| 8 | * as published by the Free Software Foundation |
| 9 | */ |
| 10 | |
| 11 | #include <linux/module.h> |
| 12 | #include <linux/moduleparam.h> |
| 13 | #include <linux/types.h> |
| 14 | #include <linux/kernel.h> |
| 15 | #include <linux/fs.h> |
| 16 | #include <linux/miscdevice.h> |
| 17 | #include <linux/platform_device.h> |
| 18 | #include <linux/watchdog.h> |
| 19 | #include <linux/uaccess.h> |
| 20 | #include <linux/gpio.h> |
| 21 | |
| 22 | #include <linux/mfd/wm831x/core.h> |
| 23 | #include <linux/mfd/wm831x/pdata.h> |
| 24 | #include <linux/mfd/wm831x/watchdog.h> |
| 25 | |
| 26 | static int nowayout = WATCHDOG_NOWAYOUT; |
| 27 | module_param(nowayout, int, 0); |
| 28 | MODULE_PARM_DESC(nowayout, |
| 29 | "Watchdog cannot be stopped once started (default=" |
| 30 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
| 31 | |
| 32 | static unsigned long wm831x_wdt_users; |
| 33 | static struct miscdevice wm831x_wdt_miscdev; |
| 34 | static int wm831x_wdt_expect_close; |
| 35 | static DEFINE_MUTEX(wdt_mutex); |
| 36 | static struct wm831x *wm831x; |
| 37 | static unsigned int update_gpio; |
| 38 | static unsigned int update_state; |
| 39 | |
| 40 | /* We can't use the sub-second values here but they're included |
| 41 | * for completeness. */ |
| 42 | static struct { |
| 43 | int time; /* Seconds */ |
| 44 | u16 val; /* WDOG_TO value */ |
| 45 | } wm831x_wdt_cfgs[] = { |
| 46 | { 1, 2 }, |
| 47 | { 2, 3 }, |
| 48 | { 4, 4 }, |
| 49 | { 8, 5 }, |
| 50 | { 16, 6 }, |
| 51 | { 32, 7 }, |
| 52 | { 33, 7 }, /* Actually 32.768s so include both, others round down */ |
| 53 | }; |
| 54 | |
| 55 | static int wm831x_wdt_set_timeout(struct wm831x *wm831x, u16 value) |
| 56 | { |
| 57 | int ret; |
| 58 | |
| 59 | mutex_lock(&wdt_mutex); |
| 60 | |
| 61 | ret = wm831x_reg_unlock(wm831x); |
| 62 | if (ret == 0) { |
| 63 | ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG, |
| 64 | WM831X_WDOG_TO_MASK, value); |
| 65 | wm831x_reg_lock(wm831x); |
| 66 | } else { |
| 67 | dev_err(wm831x->dev, "Failed to unlock security key: %d\n", |
| 68 | ret); |
| 69 | } |
| 70 | |
| 71 | mutex_unlock(&wdt_mutex); |
| 72 | |
| 73 | return ret; |
| 74 | } |
| 75 | |
| 76 | static int wm831x_wdt_start(struct wm831x *wm831x) |
| 77 | { |
| 78 | int ret; |
| 79 | |
| 80 | mutex_lock(&wdt_mutex); |
| 81 | |
| 82 | ret = wm831x_reg_unlock(wm831x); |
| 83 | if (ret == 0) { |
| 84 | ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG, |
| 85 | WM831X_WDOG_ENA, WM831X_WDOG_ENA); |
| 86 | wm831x_reg_lock(wm831x); |
| 87 | } else { |
| 88 | dev_err(wm831x->dev, "Failed to unlock security key: %d\n", |
| 89 | ret); |
| 90 | } |
| 91 | |
| 92 | mutex_unlock(&wdt_mutex); |
| 93 | |
| 94 | return ret; |
| 95 | } |
| 96 | |
| 97 | static int wm831x_wdt_stop(struct wm831x *wm831x) |
| 98 | { |
| 99 | int ret; |
| 100 | |
| 101 | mutex_lock(&wdt_mutex); |
| 102 | |
| 103 | ret = wm831x_reg_unlock(wm831x); |
| 104 | if (ret == 0) { |
| 105 | ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG, |
| 106 | WM831X_WDOG_ENA, 0); |
| 107 | wm831x_reg_lock(wm831x); |
| 108 | } else { |
| 109 | dev_err(wm831x->dev, "Failed to unlock security key: %d\n", |
| 110 | ret); |
| 111 | } |
| 112 | |
| 113 | mutex_unlock(&wdt_mutex); |
| 114 | |
| 115 | return ret; |
| 116 | } |
| 117 | |
| 118 | static int wm831x_wdt_kick(struct wm831x *wm831x) |
| 119 | { |
| 120 | int ret; |
| 121 | u16 reg; |
| 122 | |
| 123 | mutex_lock(&wdt_mutex); |
| 124 | |
| 125 | if (update_gpio) { |
| 126 | gpio_set_value_cansleep(update_gpio, update_state); |
| 127 | update_state = !update_state; |
| 128 | ret = 0; |
| 129 | goto out; |
| 130 | } |
| 131 | |
| 132 | |
| 133 | reg = wm831x_reg_read(wm831x, WM831X_WATCHDOG); |
| 134 | |
| 135 | if (!(reg & WM831X_WDOG_RST_SRC)) { |
| 136 | dev_err(wm831x->dev, "Hardware watchdog update unsupported\n"); |
| 137 | ret = -EINVAL; |
| 138 | goto out; |
| 139 | } |
| 140 | |
| 141 | reg |= WM831X_WDOG_RESET; |
| 142 | |
| 143 | ret = wm831x_reg_unlock(wm831x); |
| 144 | if (ret == 0) { |
| 145 | ret = wm831x_reg_write(wm831x, WM831X_WATCHDOG, reg); |
| 146 | wm831x_reg_lock(wm831x); |
| 147 | } else { |
| 148 | dev_err(wm831x->dev, "Failed to unlock security key: %d\n", |
| 149 | ret); |
| 150 | } |
| 151 | |
| 152 | out: |
| 153 | mutex_unlock(&wdt_mutex); |
| 154 | |
| 155 | return ret; |
| 156 | } |
| 157 | |
| 158 | static int wm831x_wdt_open(struct inode *inode, struct file *file) |
| 159 | { |
| 160 | int ret; |
| 161 | |
| 162 | if (!wm831x) |
| 163 | return -ENODEV; |
| 164 | |
| 165 | if (test_and_set_bit(0, &wm831x_wdt_users)) |
| 166 | return -EBUSY; |
| 167 | |
| 168 | ret = wm831x_wdt_start(wm831x); |
| 169 | if (ret != 0) |
| 170 | return ret; |
| 171 | |
| 172 | return nonseekable_open(inode, file); |
| 173 | } |
| 174 | |
| 175 | static int wm831x_wdt_release(struct inode *inode, struct file *file) |
| 176 | { |
| 177 | if (wm831x_wdt_expect_close) |
| 178 | wm831x_wdt_stop(wm831x); |
| 179 | else { |
| 180 | dev_warn(wm831x->dev, "Watchdog device closed uncleanly\n"); |
| 181 | wm831x_wdt_kick(wm831x); |
| 182 | } |
| 183 | |
| 184 | clear_bit(0, &wm831x_wdt_users); |
| 185 | |
| 186 | return 0; |
| 187 | } |
| 188 | |
| 189 | static ssize_t wm831x_wdt_write(struct file *file, |
| 190 | const char __user *data, size_t count, |
| 191 | loff_t *ppos) |
| 192 | { |
| 193 | size_t i; |
| 194 | |
| 195 | if (count) { |
| 196 | wm831x_wdt_kick(wm831x); |
| 197 | |
| 198 | if (!nowayout) { |
| 199 | /* In case it was set long ago */ |
| 200 | wm831x_wdt_expect_close = 0; |
| 201 | |
| 202 | /* scan to see whether or not we got the magic |
| 203 | character */ |
| 204 | for (i = 0; i != count; i++) { |
| 205 | char c; |
| 206 | if (get_user(c, data + i)) |
| 207 | return -EFAULT; |
| 208 | if (c == 'V') |
| 209 | wm831x_wdt_expect_close = 42; |
| 210 | } |
| 211 | } |
| 212 | } |
| 213 | return count; |
| 214 | } |
| 215 | |
Wim Van Sebroeck | 42747d7 | 2009-12-26 18:55:22 +0000 | [diff] [blame] | 216 | static const struct watchdog_info ident = { |
Mark Brown | 502a0106 | 2009-07-27 14:46:12 +0100 | [diff] [blame] | 217 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, |
| 218 | .identity = "WM831x Watchdog", |
| 219 | }; |
| 220 | |
| 221 | static long wm831x_wdt_ioctl(struct file *file, unsigned int cmd, |
| 222 | unsigned long arg) |
| 223 | { |
| 224 | int ret = -ENOTTY, time, i; |
| 225 | void __user *argp = (void __user *)arg; |
| 226 | int __user *p = argp; |
| 227 | u16 reg; |
| 228 | |
| 229 | switch (cmd) { |
| 230 | case WDIOC_GETSUPPORT: |
| 231 | ret = copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; |
| 232 | break; |
| 233 | |
| 234 | case WDIOC_GETSTATUS: |
| 235 | case WDIOC_GETBOOTSTATUS: |
| 236 | ret = put_user(0, p); |
| 237 | break; |
| 238 | |
| 239 | case WDIOC_SETOPTIONS: |
| 240 | { |
| 241 | int options; |
| 242 | |
| 243 | if (get_user(options, p)) |
| 244 | return -EFAULT; |
| 245 | |
| 246 | ret = -EINVAL; |
| 247 | |
| 248 | /* Setting both simultaneously means at least one must fail */ |
| 249 | if (options == WDIOS_DISABLECARD) |
| 250 | ret = wm831x_wdt_start(wm831x); |
| 251 | |
| 252 | if (options == WDIOS_ENABLECARD) |
| 253 | ret = wm831x_wdt_stop(wm831x); |
| 254 | break; |
| 255 | } |
| 256 | |
| 257 | case WDIOC_KEEPALIVE: |
| 258 | ret = wm831x_wdt_kick(wm831x); |
| 259 | break; |
| 260 | |
| 261 | case WDIOC_SETTIMEOUT: |
| 262 | ret = get_user(time, p); |
| 263 | if (ret) |
| 264 | break; |
| 265 | |
| 266 | if (time == 0) { |
| 267 | if (nowayout) |
| 268 | ret = -EINVAL; |
| 269 | else |
| 270 | wm831x_wdt_stop(wm831x); |
| 271 | break; |
| 272 | } |
| 273 | |
| 274 | for (i = 0; i < ARRAY_SIZE(wm831x_wdt_cfgs); i++) |
| 275 | if (wm831x_wdt_cfgs[i].time == time) |
| 276 | break; |
| 277 | if (i == ARRAY_SIZE(wm831x_wdt_cfgs)) |
| 278 | ret = -EINVAL; |
| 279 | else |
| 280 | ret = wm831x_wdt_set_timeout(wm831x, |
| 281 | wm831x_wdt_cfgs[i].val); |
| 282 | break; |
| 283 | |
| 284 | case WDIOC_GETTIMEOUT: |
| 285 | reg = wm831x_reg_read(wm831x, WM831X_WATCHDOG); |
| 286 | reg &= WM831X_WDOG_TO_MASK; |
| 287 | for (i = 0; i < ARRAY_SIZE(wm831x_wdt_cfgs); i++) |
| 288 | if (wm831x_wdt_cfgs[i].val == reg) |
| 289 | break; |
| 290 | if (i == ARRAY_SIZE(wm831x_wdt_cfgs)) { |
| 291 | dev_warn(wm831x->dev, |
| 292 | "Unknown watchdog configuration: %x\n", reg); |
| 293 | ret = -EINVAL; |
| 294 | } else |
| 295 | ret = put_user(wm831x_wdt_cfgs[i].time, p); |
| 296 | |
| 297 | } |
| 298 | |
| 299 | return ret; |
| 300 | } |
| 301 | |
| 302 | static const struct file_operations wm831x_wdt_fops = { |
| 303 | .owner = THIS_MODULE, |
| 304 | .llseek = no_llseek, |
| 305 | .write = wm831x_wdt_write, |
| 306 | .unlocked_ioctl = wm831x_wdt_ioctl, |
| 307 | .open = wm831x_wdt_open, |
| 308 | .release = wm831x_wdt_release, |
| 309 | }; |
| 310 | |
| 311 | static struct miscdevice wm831x_wdt_miscdev = { |
| 312 | .minor = WATCHDOG_MINOR, |
| 313 | .name = "watchdog", |
| 314 | .fops = &wm831x_wdt_fops, |
| 315 | }; |
| 316 | |
| 317 | static int __devinit wm831x_wdt_probe(struct platform_device *pdev) |
| 318 | { |
| 319 | struct wm831x_pdata *chip_pdata; |
| 320 | struct wm831x_watchdog_pdata *pdata; |
| 321 | int reg, ret; |
| 322 | |
Mark Brown | 076bad7 | 2011-05-31 14:46:55 +0100 | [diff] [blame] | 323 | if (wm831x) { |
| 324 | dev_err(&pdev->dev, "wm831x watchdog already registered\n"); |
| 325 | return -EBUSY; |
| 326 | } |
| 327 | |
Mark Brown | 502a0106 | 2009-07-27 14:46:12 +0100 | [diff] [blame] | 328 | wm831x = dev_get_drvdata(pdev->dev.parent); |
| 329 | |
| 330 | ret = wm831x_reg_read(wm831x, WM831X_WATCHDOG); |
| 331 | if (ret < 0) { |
| 332 | dev_err(wm831x->dev, "Failed to read watchdog status: %d\n", |
| 333 | ret); |
| 334 | goto err; |
| 335 | } |
| 336 | reg = ret; |
| 337 | |
| 338 | if (reg & WM831X_WDOG_DEBUG) |
| 339 | dev_warn(wm831x->dev, "Watchdog is paused\n"); |
| 340 | |
| 341 | /* Apply any configuration */ |
| 342 | if (pdev->dev.parent->platform_data) { |
| 343 | chip_pdata = pdev->dev.parent->platform_data; |
| 344 | pdata = chip_pdata->watchdog; |
| 345 | } else { |
| 346 | pdata = NULL; |
| 347 | } |
| 348 | |
| 349 | if (pdata) { |
| 350 | reg &= ~(WM831X_WDOG_SECACT_MASK | WM831X_WDOG_PRIMACT_MASK | |
| 351 | WM831X_WDOG_RST_SRC); |
| 352 | |
| 353 | reg |= pdata->primary << WM831X_WDOG_PRIMACT_SHIFT; |
| 354 | reg |= pdata->secondary << WM831X_WDOG_SECACT_SHIFT; |
| 355 | reg |= pdata->software << WM831X_WDOG_RST_SRC_SHIFT; |
| 356 | |
| 357 | if (pdata->update_gpio) { |
| 358 | ret = gpio_request(pdata->update_gpio, |
| 359 | "Watchdog update"); |
| 360 | if (ret < 0) { |
| 361 | dev_err(wm831x->dev, |
| 362 | "Failed to request update GPIO: %d\n", |
| 363 | ret); |
| 364 | goto err; |
| 365 | } |
| 366 | |
| 367 | ret = gpio_direction_output(pdata->update_gpio, 0); |
| 368 | if (ret != 0) { |
| 369 | dev_err(wm831x->dev, |
| 370 | "gpio_direction_output returned: %d\n", |
| 371 | ret); |
| 372 | goto err_gpio; |
| 373 | } |
| 374 | |
| 375 | update_gpio = pdata->update_gpio; |
| 376 | |
| 377 | /* Make sure the watchdog takes hardware updates */ |
| 378 | reg |= WM831X_WDOG_RST_SRC; |
| 379 | } |
| 380 | |
| 381 | ret = wm831x_reg_unlock(wm831x); |
| 382 | if (ret == 0) { |
| 383 | ret = wm831x_reg_write(wm831x, WM831X_WATCHDOG, reg); |
| 384 | wm831x_reg_lock(wm831x); |
| 385 | } else { |
| 386 | dev_err(wm831x->dev, |
| 387 | "Failed to unlock security key: %d\n", ret); |
| 388 | goto err_gpio; |
| 389 | } |
| 390 | } |
| 391 | |
| 392 | wm831x_wdt_miscdev.parent = &pdev->dev; |
| 393 | |
| 394 | ret = misc_register(&wm831x_wdt_miscdev); |
| 395 | if (ret != 0) { |
| 396 | dev_err(wm831x->dev, "Failed to register miscdev: %d\n", ret); |
| 397 | goto err_gpio; |
| 398 | } |
| 399 | |
| 400 | return 0; |
| 401 | |
| 402 | err_gpio: |
| 403 | if (update_gpio) { |
| 404 | gpio_free(update_gpio); |
| 405 | update_gpio = 0; |
| 406 | } |
| 407 | err: |
| 408 | return ret; |
| 409 | } |
| 410 | |
| 411 | static int __devexit wm831x_wdt_remove(struct platform_device *pdev) |
| 412 | { |
| 413 | if (update_gpio) { |
| 414 | gpio_free(update_gpio); |
| 415 | update_gpio = 0; |
| 416 | } |
| 417 | |
| 418 | misc_deregister(&wm831x_wdt_miscdev); |
| 419 | |
| 420 | return 0; |
| 421 | } |
| 422 | |
| 423 | static struct platform_driver wm831x_wdt_driver = { |
| 424 | .probe = wm831x_wdt_probe, |
| 425 | .remove = __devexit_p(wm831x_wdt_remove), |
| 426 | .driver = { |
| 427 | .name = "wm831x-watchdog", |
| 428 | }, |
| 429 | }; |
| 430 | |
| 431 | static int __init wm831x_wdt_init(void) |
| 432 | { |
| 433 | return platform_driver_register(&wm831x_wdt_driver); |
| 434 | } |
| 435 | module_init(wm831x_wdt_init); |
| 436 | |
| 437 | static void __exit wm831x_wdt_exit(void) |
| 438 | { |
| 439 | platform_driver_unregister(&wm831x_wdt_driver); |
| 440 | } |
| 441 | module_exit(wm831x_wdt_exit); |
| 442 | |
| 443 | MODULE_AUTHOR("Mark Brown"); |
| 444 | MODULE_DESCRIPTION("WM831x Watchdog"); |
| 445 | MODULE_LICENSE("GPL"); |
| 446 | MODULE_ALIAS("platform:wm831x-watchdog"); |