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 bool nowayout = WATCHDOG_NOWAYOUT; 26 module_param(nowayout, bool, 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 wdt_dev->timeout = timeout; 167 168 return ret; 169 } 170 171 static const struct watchdog_info wm831x_wdt_info = { 172 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, 173 .identity = "WM831x Watchdog", 174 }; 175 176 static const struct watchdog_ops wm831x_wdt_ops = { 177 .owner = THIS_MODULE, 178 .start = wm831x_wdt_start, 179 .stop = wm831x_wdt_stop, 180 .ping = wm831x_wdt_ping, 181 .set_timeout = wm831x_wdt_set_timeout, 182 }; 183 184 static int wm831x_wdt_probe(struct platform_device *pdev) 185 { 186 struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent); 187 struct wm831x_pdata *chip_pdata = dev_get_platdata(pdev->dev.parent); 188 struct wm831x_watchdog_pdata *pdata; 189 struct wm831x_wdt_drvdata *driver_data; 190 struct watchdog_device *wm831x_wdt; 191 int reg, ret, i; 192 193 ret = wm831x_reg_read(wm831x, WM831X_WATCHDOG); 194 if (ret < 0) { 195 dev_err(wm831x->dev, "Failed to read watchdog status: %d\n", 196 ret); 197 goto err; 198 } 199 reg = ret; 200 201 if (reg & WM831X_WDOG_DEBUG) 202 dev_warn(wm831x->dev, "Watchdog is paused\n"); 203 204 driver_data = devm_kzalloc(&pdev->dev, sizeof(*driver_data), 205 GFP_KERNEL); 206 if (!driver_data) { 207 ret = -ENOMEM; 208 goto err; 209 } 210 211 mutex_init(&driver_data->lock); 212 driver_data->wm831x = wm831x; 213 214 wm831x_wdt = &driver_data->wdt; 215 216 wm831x_wdt->info = &wm831x_wdt_info; 217 wm831x_wdt->ops = &wm831x_wdt_ops; 218 wm831x_wdt->parent = &pdev->dev; 219 watchdog_set_nowayout(wm831x_wdt, nowayout); 220 watchdog_set_drvdata(wm831x_wdt, driver_data); 221 222 reg = wm831x_reg_read(wm831x, WM831X_WATCHDOG); 223 reg &= WM831X_WDOG_TO_MASK; 224 for (i = 0; i < ARRAY_SIZE(wm831x_wdt_cfgs); i++) 225 if (wm831x_wdt_cfgs[i].val == reg) 226 break; 227 if (i == ARRAY_SIZE(wm831x_wdt_cfgs)) 228 dev_warn(wm831x->dev, 229 "Unknown watchdog timeout: %x\n", reg); 230 else 231 wm831x_wdt->timeout = wm831x_wdt_cfgs[i].time; 232 233 /* Apply any configuration */ 234 if (chip_pdata) 235 pdata = chip_pdata->watchdog; 236 else 237 pdata = NULL; 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 = devm_gpio_request_one(&pdev->dev, 249 pdata->update_gpio, 250 GPIOF_OUT_INIT_LOW, 251 "Watchdog update"); 252 if (ret < 0) { 253 dev_err(wm831x->dev, 254 "Failed to request update GPIO: %d\n", 255 ret); 256 goto err; 257 } 258 259 driver_data->update_gpio = pdata->update_gpio; 260 261 /* Make sure the watchdog takes hardware updates */ 262 reg |= WM831X_WDOG_RST_SRC; 263 } 264 265 ret = wm831x_reg_unlock(wm831x); 266 if (ret == 0) { 267 ret = wm831x_reg_write(wm831x, WM831X_WATCHDOG, reg); 268 wm831x_reg_lock(wm831x); 269 } else { 270 dev_err(wm831x->dev, 271 "Failed to unlock security key: %d\n", ret); 272 goto err; 273 } 274 } 275 276 ret = watchdog_register_device(&driver_data->wdt); 277 if (ret != 0) { 278 dev_err(wm831x->dev, "watchdog_register_device() failed: %d\n", 279 ret); 280 goto err; 281 } 282 283 platform_set_drvdata(pdev, driver_data); 284 285 return 0; 286 287 err: 288 return ret; 289 } 290 291 static int wm831x_wdt_remove(struct platform_device *pdev) 292 { 293 struct wm831x_wdt_drvdata *driver_data = platform_get_drvdata(pdev); 294 295 watchdog_unregister_device(&driver_data->wdt); 296 297 return 0; 298 } 299 300 static struct platform_driver wm831x_wdt_driver = { 301 .probe = wm831x_wdt_probe, 302 .remove = wm831x_wdt_remove, 303 .driver = { 304 .name = "wm831x-watchdog", 305 }, 306 }; 307 308 module_platform_driver(wm831x_wdt_driver); 309 310 MODULE_AUTHOR("Mark Brown"); 311 MODULE_DESCRIPTION("WM831x Watchdog"); 312 MODULE_LICENSE("GPL"); 313 MODULE_ALIAS("platform:wm831x-watchdog"); 314