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/slab.h> 16 #include <linux/platform_device.h> 17 #include <linux/watchdog.h> 18 #include <linux/uaccess.h> 19 #include <linux/gpio.h> 20 21 #include <linux/mfd/wm831x/core.h> 22 #include <linux/mfd/wm831x/pdata.h> 23 #include <linux/mfd/wm831x/watchdog.h> 24 25 static int nowayout = WATCHDOG_NOWAYOUT; 26 module_param(nowayout, int, 0); 27 MODULE_PARM_DESC(nowayout, 28 "Watchdog cannot be stopped once started (default=" 29 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 30 31 struct wm831x_wdt_drvdata { 32 struct watchdog_device wdt; 33 struct wm831x *wm831x; 34 struct mutex lock; 35 int update_gpio; 36 int update_state; 37 }; 38 39 /* We can't use the sub-second values here but they're included 40 * for completeness. */ 41 static struct { 42 unsigned int time; /* Seconds */ 43 u16 val; /* WDOG_TO value */ 44 } wm831x_wdt_cfgs[] = { 45 { 1, 2 }, 46 { 2, 3 }, 47 { 4, 4 }, 48 { 8, 5 }, 49 { 16, 6 }, 50 { 32, 7 }, 51 { 33, 7 }, /* Actually 32.768s so include both, others round down */ 52 }; 53 54 static int wm831x_wdt_start(struct watchdog_device *wdt_dev) 55 { 56 struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev); 57 struct wm831x *wm831x = driver_data->wm831x; 58 int ret; 59 60 mutex_lock(&driver_data->lock); 61 62 ret = wm831x_reg_unlock(wm831x); 63 if (ret == 0) { 64 ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG, 65 WM831X_WDOG_ENA, WM831X_WDOG_ENA); 66 wm831x_reg_lock(wm831x); 67 } else { 68 dev_err(wm831x->dev, "Failed to unlock security key: %d\n", 69 ret); 70 } 71 72 mutex_unlock(&driver_data->lock); 73 74 return ret; 75 } 76 77 static int wm831x_wdt_stop(struct watchdog_device *wdt_dev) 78 { 79 struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev); 80 struct wm831x *wm831x = driver_data->wm831x; 81 int ret; 82 83 mutex_lock(&driver_data->lock); 84 85 ret = wm831x_reg_unlock(wm831x); 86 if (ret == 0) { 87 ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG, 88 WM831X_WDOG_ENA, 0); 89 wm831x_reg_lock(wm831x); 90 } else { 91 dev_err(wm831x->dev, "Failed to unlock security key: %d\n", 92 ret); 93 } 94 95 mutex_unlock(&driver_data->lock); 96 97 return ret; 98 } 99 100 static int wm831x_wdt_ping(struct watchdog_device *wdt_dev) 101 { 102 struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev); 103 struct wm831x *wm831x = driver_data->wm831x; 104 int ret; 105 u16 reg; 106 107 mutex_lock(&driver_data->lock); 108 109 if (driver_data->update_gpio) { 110 gpio_set_value_cansleep(driver_data->update_gpio, 111 driver_data->update_state); 112 driver_data->update_state = !driver_data->update_state; 113 ret = 0; 114 goto out; 115 } 116 117 reg = wm831x_reg_read(wm831x, WM831X_WATCHDOG); 118 119 if (!(reg & WM831X_WDOG_RST_SRC)) { 120 dev_err(wm831x->dev, "Hardware watchdog update unsupported\n"); 121 ret = -EINVAL; 122 goto out; 123 } 124 125 reg |= WM831X_WDOG_RESET; 126 127 ret = wm831x_reg_unlock(wm831x); 128 if (ret == 0) { 129 ret = wm831x_reg_write(wm831x, WM831X_WATCHDOG, reg); 130 wm831x_reg_lock(wm831x); 131 } else { 132 dev_err(wm831x->dev, "Failed to unlock security key: %d\n", 133 ret); 134 } 135 136 out: 137 mutex_unlock(&driver_data->lock); 138 139 return ret; 140 } 141 142 static int wm831x_wdt_set_timeout(struct watchdog_device *wdt_dev, 143 unsigned int timeout) 144 { 145 struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev); 146 struct wm831x *wm831x = driver_data->wm831x; 147 int ret, i; 148 149 for (i = 0; i < ARRAY_SIZE(wm831x_wdt_cfgs); i++) 150 if (wm831x_wdt_cfgs[i].time == timeout) 151 break; 152 if (i == ARRAY_SIZE(wm831x_wdt_cfgs)) 153 return -EINVAL; 154 155 ret = wm831x_reg_unlock(wm831x); 156 if (ret == 0) { 157 ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG, 158 WM831X_WDOG_TO_MASK, 159 wm831x_wdt_cfgs[i].val); 160 wm831x_reg_lock(wm831x); 161 } else { 162 dev_err(wm831x->dev, "Failed to unlock security key: %d\n", 163 ret); 164 } 165 166 return ret; 167 } 168 169 static const struct watchdog_info wm831x_wdt_info = { 170 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, 171 .identity = "WM831x Watchdog", 172 }; 173 174 static const struct watchdog_ops wm831x_wdt_ops = { 175 .owner = THIS_MODULE, 176 .start = wm831x_wdt_start, 177 .stop = wm831x_wdt_stop, 178 .ping = wm831x_wdt_ping, 179 .set_timeout = wm831x_wdt_set_timeout, 180 }; 181 182 static int __devinit wm831x_wdt_probe(struct platform_device *pdev) 183 { 184 struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent); 185 struct wm831x_pdata *chip_pdata; 186 struct wm831x_watchdog_pdata *pdata; 187 struct wm831x_wdt_drvdata *driver_data; 188 struct watchdog_device *wm831x_wdt; 189 int reg, ret, i; 190 191 ret = wm831x_reg_read(wm831x, WM831X_WATCHDOG); 192 if (ret < 0) { 193 dev_err(wm831x->dev, "Failed to read watchdog status: %d\n", 194 ret); 195 goto err; 196 } 197 reg = ret; 198 199 if (reg & WM831X_WDOG_DEBUG) 200 dev_warn(wm831x->dev, "Watchdog is paused\n"); 201 202 driver_data = devm_kzalloc(&pdev->dev, sizeof(*driver_data), 203 GFP_KERNEL); 204 if (!driver_data) { 205 dev_err(wm831x->dev, "Unable to alloacate watchdog device\n"); 206 ret = -ENOMEM; 207 goto err; 208 } 209 210 mutex_init(&driver_data->lock); 211 driver_data->wm831x = wm831x; 212 213 wm831x_wdt = &driver_data->wdt; 214 215 wm831x_wdt->info = &wm831x_wdt_info; 216 wm831x_wdt->ops = &wm831x_wdt_ops; 217 watchdog_set_nowayout(wm831x_wdt, nowayout); 218 watchdog_set_drvdata(wm831x_wdt, driver_data); 219 220 reg = wm831x_reg_read(wm831x, WM831X_WATCHDOG); 221 reg &= WM831X_WDOG_TO_MASK; 222 for (i = 0; i < ARRAY_SIZE(wm831x_wdt_cfgs); i++) 223 if (wm831x_wdt_cfgs[i].val == reg) 224 break; 225 if (i == ARRAY_SIZE(wm831x_wdt_cfgs)) 226 dev_warn(wm831x->dev, 227 "Unknown watchdog timeout: %x\n", reg); 228 else 229 wm831x_wdt->timeout = wm831x_wdt_cfgs[i].time; 230 231 /* Apply any configuration */ 232 if (pdev->dev.parent->platform_data) { 233 chip_pdata = pdev->dev.parent->platform_data; 234 pdata = chip_pdata->watchdog; 235 } else { 236 pdata = NULL; 237 } 238 239 if (pdata) { 240 reg &= ~(WM831X_WDOG_SECACT_MASK | WM831X_WDOG_PRIMACT_MASK | 241 WM831X_WDOG_RST_SRC); 242 243 reg |= pdata->primary << WM831X_WDOG_PRIMACT_SHIFT; 244 reg |= pdata->secondary << WM831X_WDOG_SECACT_SHIFT; 245 reg |= pdata->software << WM831X_WDOG_RST_SRC_SHIFT; 246 247 if (pdata->update_gpio) { 248 ret = gpio_request(pdata->update_gpio, 249 "Watchdog update"); 250 if (ret < 0) { 251 dev_err(wm831x->dev, 252 "Failed to request update GPIO: %d\n", 253 ret); 254 goto err; 255 } 256 257 ret = gpio_direction_output(pdata->update_gpio, 0); 258 if (ret != 0) { 259 dev_err(wm831x->dev, 260 "gpio_direction_output returned: %d\n", 261 ret); 262 goto err_gpio; 263 } 264 265 driver_data->update_gpio = pdata->update_gpio; 266 267 /* Make sure the watchdog takes hardware updates */ 268 reg |= WM831X_WDOG_RST_SRC; 269 } 270 271 ret = wm831x_reg_unlock(wm831x); 272 if (ret == 0) { 273 ret = wm831x_reg_write(wm831x, WM831X_WATCHDOG, reg); 274 wm831x_reg_lock(wm831x); 275 } else { 276 dev_err(wm831x->dev, 277 "Failed to unlock security key: %d\n", ret); 278 goto err_gpio; 279 } 280 } 281 282 ret = watchdog_register_device(&driver_data->wdt); 283 if (ret != 0) { 284 dev_err(wm831x->dev, "watchdog_register_device() failed: %d\n", 285 ret); 286 goto err_gpio; 287 } 288 289 dev_set_drvdata(&pdev->dev, driver_data); 290 291 return 0; 292 293 err_gpio: 294 if (driver_data->update_gpio) 295 gpio_free(driver_data->update_gpio); 296 err: 297 return ret; 298 } 299 300 static int __devexit wm831x_wdt_remove(struct platform_device *pdev) 301 { 302 struct wm831x_wdt_drvdata *driver_data = dev_get_drvdata(&pdev->dev); 303 304 watchdog_unregister_device(&driver_data->wdt); 305 306 if (driver_data->update_gpio) 307 gpio_free(driver_data->update_gpio); 308 309 return 0; 310 } 311 312 static struct platform_driver wm831x_wdt_driver = { 313 .probe = wm831x_wdt_probe, 314 .remove = __devexit_p(wm831x_wdt_remove), 315 .driver = { 316 .name = "wm831x-watchdog", 317 }, 318 }; 319 320 module_platform_driver(wm831x_wdt_driver); 321 322 MODULE_AUTHOR("Mark Brown"); 323 MODULE_DESCRIPTION("WM831x Watchdog"); 324 MODULE_LICENSE("GPL"); 325 MODULE_ALIAS("platform:wm831x-watchdog"); 326