rtc-brcmstb-waketimer.c 7.4 KB

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  1. // SPDX-License-Identifier: GPL-2.0-only
  2. /*
  3. * Copyright © 2014-2017 Broadcom
  4. */
  5. #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  6. #include <linux/clk.h>
  7. #include <linux/device.h>
  8. #include <linux/err.h>
  9. #include <linux/init.h>
  10. #include <linux/interrupt.h>
  11. #include <linux/io.h>
  12. #include <linux/irqreturn.h>
  13. #include <linux/kernel.h>
  14. #include <linux/module.h>
  15. #include <linux/of.h>
  16. #include <linux/platform_device.h>
  17. #include <linux/pm.h>
  18. #include <linux/pm_wakeup.h>
  19. #include <linux/reboot.h>
  20. #include <linux/rtc.h>
  21. #include <linux/stat.h>
  22. #include <linux/suspend.h>
  23. struct brcmstb_waketmr {
  24. struct rtc_device *rtc;
  25. struct device *dev;
  26. void __iomem *base;
  27. int irq;
  28. struct notifier_block reboot_notifier;
  29. struct clk *clk;
  30. u32 rate;
  31. };
  32. #define BRCMSTB_WKTMR_EVENT 0x00
  33. #define BRCMSTB_WKTMR_COUNTER 0x04
  34. #define BRCMSTB_WKTMR_ALARM 0x08
  35. #define BRCMSTB_WKTMR_PRESCALER 0x0C
  36. #define BRCMSTB_WKTMR_PRESCALER_VAL 0x10
  37. #define BRCMSTB_WKTMR_DEFAULT_FREQ 27000000
  38. static inline void brcmstb_waketmr_clear_alarm(struct brcmstb_waketmr *timer)
  39. {
  40. writel_relaxed(1, timer->base + BRCMSTB_WKTMR_EVENT);
  41. (void)readl_relaxed(timer->base + BRCMSTB_WKTMR_EVENT);
  42. }
  43. static void brcmstb_waketmr_set_alarm(struct brcmstb_waketmr *timer,
  44. unsigned int secs)
  45. {
  46. brcmstb_waketmr_clear_alarm(timer);
  47. /* Make sure we are actually counting in seconds */
  48. writel_relaxed(timer->rate, timer->base + BRCMSTB_WKTMR_PRESCALER);
  49. writel_relaxed(secs + 1, timer->base + BRCMSTB_WKTMR_ALARM);
  50. }
  51. static irqreturn_t brcmstb_waketmr_irq(int irq, void *data)
  52. {
  53. struct brcmstb_waketmr *timer = data;
  54. pm_wakeup_event(timer->dev, 0);
  55. return IRQ_HANDLED;
  56. }
  57. struct wktmr_time {
  58. u32 sec;
  59. u32 pre;
  60. };
  61. static void wktmr_read(struct brcmstb_waketmr *timer,
  62. struct wktmr_time *t)
  63. {
  64. u32 tmp;
  65. do {
  66. t->sec = readl_relaxed(timer->base + BRCMSTB_WKTMR_COUNTER);
  67. tmp = readl_relaxed(timer->base + BRCMSTB_WKTMR_PRESCALER_VAL);
  68. } while (tmp >= timer->rate);
  69. t->pre = timer->rate - tmp;
  70. }
  71. static int brcmstb_waketmr_prepare_suspend(struct brcmstb_waketmr *timer)
  72. {
  73. struct device *dev = timer->dev;
  74. int ret = 0;
  75. if (device_may_wakeup(dev)) {
  76. ret = enable_irq_wake(timer->irq);
  77. if (ret) {
  78. dev_err(dev, "failed to enable wake-up interrupt\n");
  79. return ret;
  80. }
  81. }
  82. return ret;
  83. }
  84. /* If enabled as a wakeup-source, arm the timer when powering off */
  85. static int brcmstb_waketmr_reboot(struct notifier_block *nb,
  86. unsigned long action, void *data)
  87. {
  88. struct brcmstb_waketmr *timer;
  89. timer = container_of(nb, struct brcmstb_waketmr, reboot_notifier);
  90. /* Set timer for cold boot */
  91. if (action == SYS_POWER_OFF)
  92. brcmstb_waketmr_prepare_suspend(timer);
  93. return NOTIFY_DONE;
  94. }
  95. static int brcmstb_waketmr_gettime(struct device *dev,
  96. struct rtc_time *tm)
  97. {
  98. struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
  99. struct wktmr_time now;
  100. wktmr_read(timer, &now);
  101. rtc_time64_to_tm(now.sec, tm);
  102. return 0;
  103. }
  104. static int brcmstb_waketmr_settime(struct device *dev,
  105. struct rtc_time *tm)
  106. {
  107. struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
  108. time64_t sec;
  109. sec = rtc_tm_to_time64(tm);
  110. writel_relaxed(sec, timer->base + BRCMSTB_WKTMR_COUNTER);
  111. return 0;
  112. }
  113. static int brcmstb_waketmr_getalarm(struct device *dev,
  114. struct rtc_wkalrm *alarm)
  115. {
  116. struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
  117. time64_t sec;
  118. u32 reg;
  119. sec = readl_relaxed(timer->base + BRCMSTB_WKTMR_ALARM);
  120. if (sec != 0) {
  121. /* Alarm is enabled */
  122. alarm->enabled = 1;
  123. rtc_time64_to_tm(sec, &alarm->time);
  124. }
  125. reg = readl_relaxed(timer->base + BRCMSTB_WKTMR_EVENT);
  126. alarm->pending = !!(reg & 1);
  127. return 0;
  128. }
  129. static int brcmstb_waketmr_setalarm(struct device *dev,
  130. struct rtc_wkalrm *alarm)
  131. {
  132. struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
  133. time64_t sec;
  134. if (alarm->enabled)
  135. sec = rtc_tm_to_time64(&alarm->time);
  136. else
  137. sec = 0;
  138. brcmstb_waketmr_set_alarm(timer, sec);
  139. return 0;
  140. }
  141. /*
  142. * Does not do much but keep the RTC class happy. We always support
  143. * alarms.
  144. */
  145. static int brcmstb_waketmr_alarm_enable(struct device *dev,
  146. unsigned int enabled)
  147. {
  148. return 0;
  149. }
  150. static const struct rtc_class_ops brcmstb_waketmr_ops = {
  151. .read_time = brcmstb_waketmr_gettime,
  152. .set_time = brcmstb_waketmr_settime,
  153. .read_alarm = brcmstb_waketmr_getalarm,
  154. .set_alarm = brcmstb_waketmr_setalarm,
  155. .alarm_irq_enable = brcmstb_waketmr_alarm_enable,
  156. };
  157. static int brcmstb_waketmr_probe(struct platform_device *pdev)
  158. {
  159. struct device *dev = &pdev->dev;
  160. struct brcmstb_waketmr *timer;
  161. int ret;
  162. timer = devm_kzalloc(dev, sizeof(*timer), GFP_KERNEL);
  163. if (!timer)
  164. return -ENOMEM;
  165. platform_set_drvdata(pdev, timer);
  166. timer->dev = dev;
  167. timer->base = devm_platform_ioremap_resource(pdev, 0);
  168. if (IS_ERR(timer->base))
  169. return PTR_ERR(timer->base);
  170. timer->rtc = devm_rtc_allocate_device(dev);
  171. if (IS_ERR(timer->rtc))
  172. return PTR_ERR(timer->rtc);
  173. /*
  174. * Set wakeup capability before requesting wakeup interrupt, so we can
  175. * process boot-time "wakeups" (e.g., from S5 soft-off)
  176. */
  177. device_set_wakeup_capable(dev, true);
  178. device_wakeup_enable(dev);
  179. timer->irq = platform_get_irq(pdev, 0);
  180. if (timer->irq < 0)
  181. return -ENODEV;
  182. timer->clk = devm_clk_get(dev, NULL);
  183. if (!IS_ERR(timer->clk)) {
  184. ret = clk_prepare_enable(timer->clk);
  185. if (ret)
  186. return ret;
  187. timer->rate = clk_get_rate(timer->clk);
  188. if (!timer->rate)
  189. timer->rate = BRCMSTB_WKTMR_DEFAULT_FREQ;
  190. } else {
  191. timer->rate = BRCMSTB_WKTMR_DEFAULT_FREQ;
  192. timer->clk = NULL;
  193. }
  194. ret = devm_request_irq(dev, timer->irq, brcmstb_waketmr_irq, 0,
  195. "brcmstb-waketimer", timer);
  196. if (ret < 0)
  197. goto err_clk;
  198. timer->reboot_notifier.notifier_call = brcmstb_waketmr_reboot;
  199. register_reboot_notifier(&timer->reboot_notifier);
  200. timer->rtc->ops = &brcmstb_waketmr_ops;
  201. timer->rtc->range_max = U32_MAX;
  202. ret = rtc_register_device(timer->rtc);
  203. if (ret)
  204. goto err_notifier;
  205. dev_info(dev, "registered, with irq %d\n", timer->irq);
  206. return 0;
  207. err_notifier:
  208. unregister_reboot_notifier(&timer->reboot_notifier);
  209. err_clk:
  210. if (timer->clk)
  211. clk_disable_unprepare(timer->clk);
  212. return ret;
  213. }
  214. static int brcmstb_waketmr_remove(struct platform_device *pdev)
  215. {
  216. struct brcmstb_waketmr *timer = dev_get_drvdata(&pdev->dev);
  217. unregister_reboot_notifier(&timer->reboot_notifier);
  218. clk_disable_unprepare(timer->clk);
  219. return 0;
  220. }
  221. #ifdef CONFIG_PM_SLEEP
  222. static int brcmstb_waketmr_suspend(struct device *dev)
  223. {
  224. struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
  225. return brcmstb_waketmr_prepare_suspend(timer);
  226. }
  227. static int brcmstb_waketmr_resume(struct device *dev)
  228. {
  229. struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
  230. int ret;
  231. if (!device_may_wakeup(dev))
  232. return 0;
  233. ret = disable_irq_wake(timer->irq);
  234. brcmstb_waketmr_clear_alarm(timer);
  235. return ret;
  236. }
  237. #endif /* CONFIG_PM_SLEEP */
  238. static SIMPLE_DEV_PM_OPS(brcmstb_waketmr_pm_ops,
  239. brcmstb_waketmr_suspend, brcmstb_waketmr_resume);
  240. static const struct of_device_id brcmstb_waketmr_of_match[] = {
  241. { .compatible = "brcm,brcmstb-waketimer" },
  242. { /* sentinel */ },
  243. };
  244. static struct platform_driver brcmstb_waketmr_driver = {
  245. .probe = brcmstb_waketmr_probe,
  246. .remove = brcmstb_waketmr_remove,
  247. .driver = {
  248. .name = "brcmstb-waketimer",
  249. .pm = &brcmstb_waketmr_pm_ops,
  250. .of_match_table = of_match_ptr(brcmstb_waketmr_of_match),
  251. }
  252. };
  253. module_platform_driver(brcmstb_waketmr_driver);
  254. MODULE_LICENSE("GPL v2");
  255. MODULE_AUTHOR("Brian Norris");
  256. MODULE_AUTHOR("Markus Mayer");
  257. MODULE_DESCRIPTION("Wake-up timer driver for STB chips");