wm831x_wdt.c 6.2 KB

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  1. // SPDX-License-Identifier: GPL-2.0+
  2. /*
  3. * Watchdog driver for the wm831x PMICs
  4. *
  5. * Copyright (C) 2009 Wolfson Microelectronics
  6. */
  7. #include <linux/module.h>
  8. #include <linux/moduleparam.h>
  9. #include <linux/types.h>
  10. #include <linux/kernel.h>
  11. #include <linux/slab.h>
  12. #include <linux/platform_device.h>
  13. #include <linux/watchdog.h>
  14. #include <linux/uaccess.h>
  15. #include <linux/mfd/wm831x/core.h>
  16. #include <linux/mfd/wm831x/pdata.h>
  17. #include <linux/mfd/wm831x/watchdog.h>
  18. static bool nowayout = WATCHDOG_NOWAYOUT;
  19. module_param(nowayout, bool, 0);
  20. MODULE_PARM_DESC(nowayout,
  21. "Watchdog cannot be stopped once started (default="
  22. __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  23. struct wm831x_wdt_drvdata {
  24. struct watchdog_device wdt;
  25. struct wm831x *wm831x;
  26. struct mutex lock;
  27. int update_state;
  28. };
  29. /* We can't use the sub-second values here but they're included
  30. * for completeness. */
  31. static struct {
  32. unsigned int time; /* Seconds */
  33. u16 val; /* WDOG_TO value */
  34. } wm831x_wdt_cfgs[] = {
  35. { 1, 2 },
  36. { 2, 3 },
  37. { 4, 4 },
  38. { 8, 5 },
  39. { 16, 6 },
  40. { 32, 7 },
  41. { 33, 7 }, /* Actually 32.768s so include both, others round down */
  42. };
  43. static int wm831x_wdt_start(struct watchdog_device *wdt_dev)
  44. {
  45. struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev);
  46. struct wm831x *wm831x = driver_data->wm831x;
  47. int ret;
  48. mutex_lock(&driver_data->lock);
  49. ret = wm831x_reg_unlock(wm831x);
  50. if (ret == 0) {
  51. ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG,
  52. WM831X_WDOG_ENA, WM831X_WDOG_ENA);
  53. wm831x_reg_lock(wm831x);
  54. } else {
  55. dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
  56. ret);
  57. }
  58. mutex_unlock(&driver_data->lock);
  59. return ret;
  60. }
  61. static int wm831x_wdt_stop(struct watchdog_device *wdt_dev)
  62. {
  63. struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev);
  64. struct wm831x *wm831x = driver_data->wm831x;
  65. int ret;
  66. mutex_lock(&driver_data->lock);
  67. ret = wm831x_reg_unlock(wm831x);
  68. if (ret == 0) {
  69. ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG,
  70. WM831X_WDOG_ENA, 0);
  71. wm831x_reg_lock(wm831x);
  72. } else {
  73. dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
  74. ret);
  75. }
  76. mutex_unlock(&driver_data->lock);
  77. return ret;
  78. }
  79. static int wm831x_wdt_ping(struct watchdog_device *wdt_dev)
  80. {
  81. struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev);
  82. struct wm831x *wm831x = driver_data->wm831x;
  83. int ret;
  84. u16 reg;
  85. mutex_lock(&driver_data->lock);
  86. reg = wm831x_reg_read(wm831x, WM831X_WATCHDOG);
  87. if (!(reg & WM831X_WDOG_RST_SRC)) {
  88. dev_err(wm831x->dev, "Hardware watchdog update unsupported\n");
  89. ret = -EINVAL;
  90. goto out;
  91. }
  92. reg |= WM831X_WDOG_RESET;
  93. ret = wm831x_reg_unlock(wm831x);
  94. if (ret == 0) {
  95. ret = wm831x_reg_write(wm831x, WM831X_WATCHDOG, reg);
  96. wm831x_reg_lock(wm831x);
  97. } else {
  98. dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
  99. ret);
  100. }
  101. out:
  102. mutex_unlock(&driver_data->lock);
  103. return ret;
  104. }
  105. static int wm831x_wdt_set_timeout(struct watchdog_device *wdt_dev,
  106. unsigned int timeout)
  107. {
  108. struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev);
  109. struct wm831x *wm831x = driver_data->wm831x;
  110. int ret, i;
  111. for (i = 0; i < ARRAY_SIZE(wm831x_wdt_cfgs); i++)
  112. if (wm831x_wdt_cfgs[i].time == timeout)
  113. break;
  114. if (i == ARRAY_SIZE(wm831x_wdt_cfgs))
  115. return -EINVAL;
  116. ret = wm831x_reg_unlock(wm831x);
  117. if (ret == 0) {
  118. ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG,
  119. WM831X_WDOG_TO_MASK,
  120. wm831x_wdt_cfgs[i].val);
  121. wm831x_reg_lock(wm831x);
  122. } else {
  123. dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
  124. ret);
  125. }
  126. wdt_dev->timeout = timeout;
  127. return ret;
  128. }
  129. static const struct watchdog_info wm831x_wdt_info = {
  130. .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
  131. .identity = "WM831x Watchdog",
  132. };
  133. static const struct watchdog_ops wm831x_wdt_ops = {
  134. .owner = THIS_MODULE,
  135. .start = wm831x_wdt_start,
  136. .stop = wm831x_wdt_stop,
  137. .ping = wm831x_wdt_ping,
  138. .set_timeout = wm831x_wdt_set_timeout,
  139. };
  140. static int wm831x_wdt_probe(struct platform_device *pdev)
  141. {
  142. struct device *dev = &pdev->dev;
  143. struct wm831x *wm831x = dev_get_drvdata(dev->parent);
  144. struct wm831x_pdata *chip_pdata = dev_get_platdata(dev->parent);
  145. struct wm831x_watchdog_pdata *pdata;
  146. struct wm831x_wdt_drvdata *driver_data;
  147. struct watchdog_device *wm831x_wdt;
  148. int reg, ret, i;
  149. ret = wm831x_reg_read(wm831x, WM831X_WATCHDOG);
  150. if (ret < 0) {
  151. dev_err(wm831x->dev, "Failed to read watchdog status: %d\n",
  152. ret);
  153. return ret;
  154. }
  155. reg = ret;
  156. if (reg & WM831X_WDOG_DEBUG)
  157. dev_warn(wm831x->dev, "Watchdog is paused\n");
  158. driver_data = devm_kzalloc(dev, sizeof(*driver_data), GFP_KERNEL);
  159. if (!driver_data)
  160. return -ENOMEM;
  161. mutex_init(&driver_data->lock);
  162. driver_data->wm831x = wm831x;
  163. wm831x_wdt = &driver_data->wdt;
  164. wm831x_wdt->info = &wm831x_wdt_info;
  165. wm831x_wdt->ops = &wm831x_wdt_ops;
  166. wm831x_wdt->parent = dev;
  167. watchdog_set_nowayout(wm831x_wdt, nowayout);
  168. watchdog_set_drvdata(wm831x_wdt, driver_data);
  169. reg = wm831x_reg_read(wm831x, WM831X_WATCHDOG);
  170. reg &= WM831X_WDOG_TO_MASK;
  171. for (i = 0; i < ARRAY_SIZE(wm831x_wdt_cfgs); i++)
  172. if (wm831x_wdt_cfgs[i].val == reg)
  173. break;
  174. if (i == ARRAY_SIZE(wm831x_wdt_cfgs))
  175. dev_warn(wm831x->dev,
  176. "Unknown watchdog timeout: %x\n", reg);
  177. else
  178. wm831x_wdt->timeout = wm831x_wdt_cfgs[i].time;
  179. /* Apply any configuration */
  180. if (chip_pdata)
  181. pdata = chip_pdata->watchdog;
  182. else
  183. pdata = NULL;
  184. if (pdata) {
  185. reg &= ~(WM831X_WDOG_SECACT_MASK | WM831X_WDOG_PRIMACT_MASK |
  186. WM831X_WDOG_RST_SRC);
  187. reg |= pdata->primary << WM831X_WDOG_PRIMACT_SHIFT;
  188. reg |= pdata->secondary << WM831X_WDOG_SECACT_SHIFT;
  189. reg |= pdata->software << WM831X_WDOG_RST_SRC_SHIFT;
  190. ret = wm831x_reg_unlock(wm831x);
  191. if (ret == 0) {
  192. ret = wm831x_reg_write(wm831x, WM831X_WATCHDOG, reg);
  193. wm831x_reg_lock(wm831x);
  194. } else {
  195. dev_err(wm831x->dev,
  196. "Failed to unlock security key: %d\n", ret);
  197. return ret;
  198. }
  199. }
  200. return devm_watchdog_register_device(dev, &driver_data->wdt);
  201. }
  202. static struct platform_driver wm831x_wdt_driver = {
  203. .probe = wm831x_wdt_probe,
  204. .driver = {
  205. .name = "wm831x-watchdog",
  206. },
  207. };
  208. module_platform_driver(wm831x_wdt_driver);
  209. MODULE_AUTHOR("Mark Brown");
  210. MODULE_DESCRIPTION("WM831x Watchdog");
  211. MODULE_LICENSE("GPL");
  212. MODULE_ALIAS("platform:wm831x-watchdog");