digicolor_wdt.c 3.8 KB

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  1. // SPDX-License-Identifier: GPL-2.0+
  2. /*
  3. * Watchdog driver for Conexant Digicolor
  4. *
  5. * Copyright (C) 2015 Paradox Innovation Ltd.
  6. *
  7. */
  8. #include <linux/types.h>
  9. #include <linux/module.h>
  10. #include <linux/io.h>
  11. #include <linux/delay.h>
  12. #include <linux/clk.h>
  13. #include <linux/watchdog.h>
  14. #include <linux/platform_device.h>
  15. #include <linux/of_address.h>
  16. #define TIMER_A_CONTROL 0
  17. #define TIMER_A_COUNT 4
  18. #define TIMER_A_ENABLE_COUNT BIT(0)
  19. #define TIMER_A_ENABLE_WATCHDOG BIT(1)
  20. struct dc_wdt {
  21. void __iomem *base;
  22. struct clk *clk;
  23. spinlock_t lock;
  24. };
  25. static unsigned timeout;
  26. module_param(timeout, uint, 0);
  27. MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
  28. static void dc_wdt_set(struct dc_wdt *wdt, u32 ticks)
  29. {
  30. unsigned long flags;
  31. spin_lock_irqsave(&wdt->lock, flags);
  32. writel_relaxed(0, wdt->base + TIMER_A_CONTROL);
  33. writel_relaxed(ticks, wdt->base + TIMER_A_COUNT);
  34. writel_relaxed(TIMER_A_ENABLE_COUNT | TIMER_A_ENABLE_WATCHDOG,
  35. wdt->base + TIMER_A_CONTROL);
  36. spin_unlock_irqrestore(&wdt->lock, flags);
  37. }
  38. static int dc_wdt_restart(struct watchdog_device *wdog, unsigned long action,
  39. void *data)
  40. {
  41. struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
  42. dc_wdt_set(wdt, 1);
  43. /* wait for reset to assert... */
  44. mdelay(500);
  45. return 0;
  46. }
  47. static int dc_wdt_start(struct watchdog_device *wdog)
  48. {
  49. struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
  50. dc_wdt_set(wdt, wdog->timeout * clk_get_rate(wdt->clk));
  51. return 0;
  52. }
  53. static int dc_wdt_stop(struct watchdog_device *wdog)
  54. {
  55. struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
  56. writel_relaxed(0, wdt->base + TIMER_A_CONTROL);
  57. return 0;
  58. }
  59. static int dc_wdt_set_timeout(struct watchdog_device *wdog, unsigned int t)
  60. {
  61. struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
  62. dc_wdt_set(wdt, t * clk_get_rate(wdt->clk));
  63. wdog->timeout = t;
  64. return 0;
  65. }
  66. static unsigned int dc_wdt_get_timeleft(struct watchdog_device *wdog)
  67. {
  68. struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
  69. uint32_t count = readl_relaxed(wdt->base + TIMER_A_COUNT);
  70. return count / clk_get_rate(wdt->clk);
  71. }
  72. static const struct watchdog_ops dc_wdt_ops = {
  73. .owner = THIS_MODULE,
  74. .start = dc_wdt_start,
  75. .stop = dc_wdt_stop,
  76. .set_timeout = dc_wdt_set_timeout,
  77. .get_timeleft = dc_wdt_get_timeleft,
  78. .restart = dc_wdt_restart,
  79. };
  80. static const struct watchdog_info dc_wdt_info = {
  81. .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE
  82. | WDIOF_KEEPALIVEPING,
  83. .identity = "Conexant Digicolor Watchdog",
  84. };
  85. static struct watchdog_device dc_wdt_wdd = {
  86. .info = &dc_wdt_info,
  87. .ops = &dc_wdt_ops,
  88. .min_timeout = 1,
  89. };
  90. static int dc_wdt_probe(struct platform_device *pdev)
  91. {
  92. struct device *dev = &pdev->dev;
  93. struct dc_wdt *wdt;
  94. wdt = devm_kzalloc(dev, sizeof(struct dc_wdt), GFP_KERNEL);
  95. if (!wdt)
  96. return -ENOMEM;
  97. wdt->base = devm_platform_ioremap_resource(pdev, 0);
  98. if (IS_ERR(wdt->base))
  99. return PTR_ERR(wdt->base);
  100. wdt->clk = devm_clk_get(dev, NULL);
  101. if (IS_ERR(wdt->clk))
  102. return PTR_ERR(wdt->clk);
  103. dc_wdt_wdd.max_timeout = U32_MAX / clk_get_rate(wdt->clk);
  104. dc_wdt_wdd.timeout = dc_wdt_wdd.max_timeout;
  105. dc_wdt_wdd.parent = dev;
  106. spin_lock_init(&wdt->lock);
  107. watchdog_set_drvdata(&dc_wdt_wdd, wdt);
  108. watchdog_set_restart_priority(&dc_wdt_wdd, 128);
  109. watchdog_init_timeout(&dc_wdt_wdd, timeout, dev);
  110. watchdog_stop_on_reboot(&dc_wdt_wdd);
  111. return devm_watchdog_register_device(dev, &dc_wdt_wdd);
  112. }
  113. static const struct of_device_id dc_wdt_of_match[] = {
  114. { .compatible = "cnxt,cx92755-wdt", },
  115. {},
  116. };
  117. MODULE_DEVICE_TABLE(of, dc_wdt_of_match);
  118. static struct platform_driver dc_wdt_driver = {
  119. .probe = dc_wdt_probe,
  120. .driver = {
  121. .name = "digicolor-wdt",
  122. .of_match_table = dc_wdt_of_match,
  123. },
  124. };
  125. module_platform_driver(dc_wdt_driver);
  126. MODULE_AUTHOR("Baruch Siach <baruch@tkos.co.il>");
  127. MODULE_DESCRIPTION("Driver for Conexant Digicolor watchdog timer");
  128. MODULE_LICENSE("GPL");