jz4740_wdt.c 5.1 KB

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  1. // SPDX-License-Identifier: GPL-2.0-or-later
  2. /*
  3. * Copyright (C) 2010, Paul Cercueil <paul@crapouillou.net>
  4. * JZ4740 Watchdog driver
  5. */
  6. #include <linux/mfd/ingenic-tcu.h>
  7. #include <linux/mfd/syscon.h>
  8. #include <linux/module.h>
  9. #include <linux/moduleparam.h>
  10. #include <linux/types.h>
  11. #include <linux/kernel.h>
  12. #include <linux/watchdog.h>
  13. #include <linux/platform_device.h>
  14. #include <linux/io.h>
  15. #include <linux/device.h>
  16. #include <linux/clk.h>
  17. #include <linux/slab.h>
  18. #include <linux/err.h>
  19. #include <linux/of.h>
  20. #include <linux/regmap.h>
  21. #define DEFAULT_HEARTBEAT 5
  22. #define MAX_HEARTBEAT 2048
  23. static bool nowayout = WATCHDOG_NOWAYOUT;
  24. module_param(nowayout, bool, 0);
  25. MODULE_PARM_DESC(nowayout,
  26. "Watchdog cannot be stopped once started (default="
  27. __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  28. static unsigned int heartbeat = DEFAULT_HEARTBEAT;
  29. module_param(heartbeat, uint, 0);
  30. MODULE_PARM_DESC(heartbeat,
  31. "Watchdog heartbeat period in seconds from 1 to "
  32. __MODULE_STRING(MAX_HEARTBEAT) ", default "
  33. __MODULE_STRING(DEFAULT_HEARTBEAT));
  34. struct jz4740_wdt_drvdata {
  35. struct watchdog_device wdt;
  36. struct regmap *map;
  37. struct clk *clk;
  38. unsigned long clk_rate;
  39. };
  40. static int jz4740_wdt_ping(struct watchdog_device *wdt_dev)
  41. {
  42. struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
  43. regmap_write(drvdata->map, TCU_REG_WDT_TCNT, 0);
  44. return 0;
  45. }
  46. static int jz4740_wdt_set_timeout(struct watchdog_device *wdt_dev,
  47. unsigned int new_timeout)
  48. {
  49. struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
  50. u16 timeout_value = (u16)(drvdata->clk_rate * new_timeout);
  51. unsigned int tcer;
  52. regmap_read(drvdata->map, TCU_REG_WDT_TCER, &tcer);
  53. regmap_write(drvdata->map, TCU_REG_WDT_TCER, 0);
  54. regmap_write(drvdata->map, TCU_REG_WDT_TDR, timeout_value);
  55. regmap_write(drvdata->map, TCU_REG_WDT_TCNT, 0);
  56. if (tcer & TCU_WDT_TCER_TCEN)
  57. regmap_write(drvdata->map, TCU_REG_WDT_TCER, TCU_WDT_TCER_TCEN);
  58. wdt_dev->timeout = new_timeout;
  59. return 0;
  60. }
  61. static int jz4740_wdt_start(struct watchdog_device *wdt_dev)
  62. {
  63. struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
  64. unsigned int tcer;
  65. int ret;
  66. ret = clk_prepare_enable(drvdata->clk);
  67. if (ret)
  68. return ret;
  69. regmap_read(drvdata->map, TCU_REG_WDT_TCER, &tcer);
  70. jz4740_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
  71. /* Start watchdog if it wasn't started already */
  72. if (!(tcer & TCU_WDT_TCER_TCEN))
  73. regmap_write(drvdata->map, TCU_REG_WDT_TCER, TCU_WDT_TCER_TCEN);
  74. return 0;
  75. }
  76. static int jz4740_wdt_stop(struct watchdog_device *wdt_dev)
  77. {
  78. struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
  79. regmap_write(drvdata->map, TCU_REG_WDT_TCER, 0);
  80. clk_disable_unprepare(drvdata->clk);
  81. return 0;
  82. }
  83. static int jz4740_wdt_restart(struct watchdog_device *wdt_dev,
  84. unsigned long action, void *data)
  85. {
  86. wdt_dev->timeout = 0;
  87. jz4740_wdt_start(wdt_dev);
  88. return 0;
  89. }
  90. static const struct watchdog_info jz4740_wdt_info = {
  91. .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
  92. .identity = "jz4740 Watchdog",
  93. };
  94. static const struct watchdog_ops jz4740_wdt_ops = {
  95. .owner = THIS_MODULE,
  96. .start = jz4740_wdt_start,
  97. .stop = jz4740_wdt_stop,
  98. .ping = jz4740_wdt_ping,
  99. .set_timeout = jz4740_wdt_set_timeout,
  100. .restart = jz4740_wdt_restart,
  101. };
  102. #ifdef CONFIG_OF
  103. static const struct of_device_id jz4740_wdt_of_matches[] = {
  104. { .compatible = "ingenic,jz4740-watchdog", },
  105. { .compatible = "ingenic,jz4780-watchdog", },
  106. { /* sentinel */ }
  107. };
  108. MODULE_DEVICE_TABLE(of, jz4740_wdt_of_matches);
  109. #endif
  110. static int jz4740_wdt_probe(struct platform_device *pdev)
  111. {
  112. struct device *dev = &pdev->dev;
  113. struct jz4740_wdt_drvdata *drvdata;
  114. struct watchdog_device *jz4740_wdt;
  115. long rate;
  116. int ret;
  117. drvdata = devm_kzalloc(dev, sizeof(struct jz4740_wdt_drvdata),
  118. GFP_KERNEL);
  119. if (!drvdata)
  120. return -ENOMEM;
  121. drvdata->clk = devm_clk_get(&pdev->dev, "wdt");
  122. if (IS_ERR(drvdata->clk)) {
  123. dev_err(&pdev->dev, "cannot find WDT clock\n");
  124. return PTR_ERR(drvdata->clk);
  125. }
  126. /* Set smallest clock possible */
  127. rate = clk_round_rate(drvdata->clk, 1);
  128. if (rate < 0)
  129. return rate;
  130. ret = clk_set_rate(drvdata->clk, rate);
  131. if (ret)
  132. return ret;
  133. drvdata->clk_rate = rate;
  134. jz4740_wdt = &drvdata->wdt;
  135. jz4740_wdt->info = &jz4740_wdt_info;
  136. jz4740_wdt->ops = &jz4740_wdt_ops;
  137. jz4740_wdt->min_timeout = 1;
  138. jz4740_wdt->max_timeout = 0xffff / rate;
  139. jz4740_wdt->timeout = clamp(heartbeat,
  140. jz4740_wdt->min_timeout,
  141. jz4740_wdt->max_timeout);
  142. jz4740_wdt->parent = dev;
  143. watchdog_set_nowayout(jz4740_wdt, nowayout);
  144. watchdog_set_drvdata(jz4740_wdt, drvdata);
  145. drvdata->map = device_node_to_regmap(dev->parent->of_node);
  146. if (IS_ERR(drvdata->map)) {
  147. dev_err(dev, "regmap not found\n");
  148. return PTR_ERR(drvdata->map);
  149. }
  150. return devm_watchdog_register_device(dev, &drvdata->wdt);
  151. }
  152. static struct platform_driver jz4740_wdt_driver = {
  153. .probe = jz4740_wdt_probe,
  154. .driver = {
  155. .name = "jz4740-wdt",
  156. .of_match_table = of_match_ptr(jz4740_wdt_of_matches),
  157. },
  158. };
  159. module_platform_driver(jz4740_wdt_driver);
  160. MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>");
  161. MODULE_DESCRIPTION("jz4740 Watchdog Driver");
  162. MODULE_LICENSE("GPL");
  163. MODULE_ALIAS("platform:jz4740-wdt");