rtc-wm8350.c 11 KB

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  1. // SPDX-License-Identifier: GPL-2.0-or-later
  2. /*
  3. * Real Time Clock driver for Wolfson Microelectronics WM8350
  4. *
  5. * Copyright (C) 2007, 2008 Wolfson Microelectronics PLC.
  6. *
  7. * Author: Liam Girdwood
  8. * linux@wolfsonmicro.com
  9. */
  10. #include <linux/module.h>
  11. #include <linux/kernel.h>
  12. #include <linux/time.h>
  13. #include <linux/rtc.h>
  14. #include <linux/bcd.h>
  15. #include <linux/interrupt.h>
  16. #include <linux/ioctl.h>
  17. #include <linux/completion.h>
  18. #include <linux/mfd/wm8350/rtc.h>
  19. #include <linux/mfd/wm8350/core.h>
  20. #include <linux/delay.h>
  21. #include <linux/platform_device.h>
  22. #define WM8350_SET_ALM_RETRIES 5
  23. #define WM8350_SET_TIME_RETRIES 5
  24. #define WM8350_GET_TIME_RETRIES 5
  25. /*
  26. * Read current time and date in RTC
  27. */
  28. static int wm8350_rtc_readtime(struct device *dev, struct rtc_time *tm)
  29. {
  30. struct wm8350 *wm8350 = dev_get_drvdata(dev);
  31. u16 time1[4], time2[4];
  32. int retries = WM8350_GET_TIME_RETRIES, ret;
  33. /*
  34. * Read the time twice and compare.
  35. * If time1 == time2, then time is valid else retry.
  36. */
  37. do {
  38. ret = wm8350_block_read(wm8350, WM8350_RTC_SECONDS_MINUTES,
  39. 4, time1);
  40. if (ret < 0)
  41. return ret;
  42. ret = wm8350_block_read(wm8350, WM8350_RTC_SECONDS_MINUTES,
  43. 4, time2);
  44. if (ret < 0)
  45. return ret;
  46. if (memcmp(time1, time2, sizeof(time1)) == 0) {
  47. tm->tm_sec = time1[0] & WM8350_RTC_SECS_MASK;
  48. tm->tm_min = (time1[0] & WM8350_RTC_MINS_MASK)
  49. >> WM8350_RTC_MINS_SHIFT;
  50. tm->tm_hour = time1[1] & WM8350_RTC_HRS_MASK;
  51. tm->tm_wday = ((time1[1] >> WM8350_RTC_DAY_SHIFT)
  52. & 0x7) - 1;
  53. tm->tm_mon = ((time1[2] & WM8350_RTC_MTH_MASK)
  54. >> WM8350_RTC_MTH_SHIFT) - 1;
  55. tm->tm_mday = (time1[2] & WM8350_RTC_DATE_MASK);
  56. tm->tm_year = ((time1[3] & WM8350_RTC_YHUNDREDS_MASK)
  57. >> WM8350_RTC_YHUNDREDS_SHIFT) * 100;
  58. tm->tm_year += time1[3] & WM8350_RTC_YUNITS_MASK;
  59. tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon,
  60. tm->tm_year);
  61. tm->tm_year -= 1900;
  62. dev_dbg(dev, "Read (%d left): %04x %04x %04x %04x\n",
  63. retries,
  64. time1[0], time1[1], time1[2], time1[3]);
  65. return 0;
  66. }
  67. } while (retries--);
  68. dev_err(dev, "timed out reading RTC time\n");
  69. return -EIO;
  70. }
  71. /*
  72. * Set current time and date in RTC
  73. */
  74. static int wm8350_rtc_settime(struct device *dev, struct rtc_time *tm)
  75. {
  76. struct wm8350 *wm8350 = dev_get_drvdata(dev);
  77. u16 time[4];
  78. u16 rtc_ctrl;
  79. int ret, retries = WM8350_SET_TIME_RETRIES;
  80. time[0] = tm->tm_sec;
  81. time[0] |= tm->tm_min << WM8350_RTC_MINS_SHIFT;
  82. time[1] = tm->tm_hour;
  83. time[1] |= (tm->tm_wday + 1) << WM8350_RTC_DAY_SHIFT;
  84. time[2] = tm->tm_mday;
  85. time[2] |= (tm->tm_mon + 1) << WM8350_RTC_MTH_SHIFT;
  86. time[3] = ((tm->tm_year + 1900) / 100) << WM8350_RTC_YHUNDREDS_SHIFT;
  87. time[3] |= (tm->tm_year + 1900) % 100;
  88. dev_dbg(dev, "Setting: %04x %04x %04x %04x\n",
  89. time[0], time[1], time[2], time[3]);
  90. /* Set RTC_SET to stop the clock */
  91. ret = wm8350_set_bits(wm8350, WM8350_RTC_TIME_CONTROL, WM8350_RTC_SET);
  92. if (ret < 0)
  93. return ret;
  94. /* Wait until confirmation of stopping */
  95. do {
  96. rtc_ctrl = wm8350_reg_read(wm8350, WM8350_RTC_TIME_CONTROL);
  97. schedule_timeout_uninterruptible(msecs_to_jiffies(1));
  98. } while (--retries && !(rtc_ctrl & WM8350_RTC_STS));
  99. if (!retries) {
  100. dev_err(dev, "timed out on set confirmation\n");
  101. return -EIO;
  102. }
  103. /* Write time to RTC */
  104. ret = wm8350_block_write(wm8350, WM8350_RTC_SECONDS_MINUTES, 4, time);
  105. if (ret < 0)
  106. return ret;
  107. /* Clear RTC_SET to start the clock */
  108. ret = wm8350_clear_bits(wm8350, WM8350_RTC_TIME_CONTROL,
  109. WM8350_RTC_SET);
  110. return ret;
  111. }
  112. /*
  113. * Read alarm time and date in RTC
  114. */
  115. static int wm8350_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
  116. {
  117. struct wm8350 *wm8350 = dev_get_drvdata(dev);
  118. struct rtc_time *tm = &alrm->time;
  119. u16 time[4];
  120. int ret;
  121. ret = wm8350_block_read(wm8350, WM8350_ALARM_SECONDS_MINUTES, 4, time);
  122. if (ret < 0)
  123. return ret;
  124. tm->tm_sec = time[0] & WM8350_RTC_ALMSECS_MASK;
  125. if (tm->tm_sec == WM8350_RTC_ALMSECS_MASK)
  126. tm->tm_sec = -1;
  127. tm->tm_min = time[0] & WM8350_RTC_ALMMINS_MASK;
  128. if (tm->tm_min == WM8350_RTC_ALMMINS_MASK)
  129. tm->tm_min = -1;
  130. else
  131. tm->tm_min >>= WM8350_RTC_ALMMINS_SHIFT;
  132. tm->tm_hour = time[1] & WM8350_RTC_ALMHRS_MASK;
  133. if (tm->tm_hour == WM8350_RTC_ALMHRS_MASK)
  134. tm->tm_hour = -1;
  135. tm->tm_wday = ((time[1] >> WM8350_RTC_ALMDAY_SHIFT) & 0x7) - 1;
  136. if (tm->tm_wday > 7)
  137. tm->tm_wday = -1;
  138. tm->tm_mon = time[2] & WM8350_RTC_ALMMTH_MASK;
  139. if (tm->tm_mon == WM8350_RTC_ALMMTH_MASK)
  140. tm->tm_mon = -1;
  141. else
  142. tm->tm_mon = (tm->tm_mon >> WM8350_RTC_ALMMTH_SHIFT) - 1;
  143. tm->tm_mday = (time[2] & WM8350_RTC_ALMDATE_MASK);
  144. if (tm->tm_mday == WM8350_RTC_ALMDATE_MASK)
  145. tm->tm_mday = -1;
  146. tm->tm_year = -1;
  147. alrm->enabled = !(time[3] & WM8350_RTC_ALMSTS);
  148. return 0;
  149. }
  150. static int wm8350_rtc_stop_alarm(struct wm8350 *wm8350)
  151. {
  152. int retries = WM8350_SET_ALM_RETRIES;
  153. u16 rtc_ctrl;
  154. int ret;
  155. /* Set RTC_SET to stop the clock */
  156. ret = wm8350_set_bits(wm8350, WM8350_RTC_TIME_CONTROL,
  157. WM8350_RTC_ALMSET);
  158. if (ret < 0)
  159. return ret;
  160. /* Wait until confirmation of stopping */
  161. do {
  162. rtc_ctrl = wm8350_reg_read(wm8350, WM8350_RTC_TIME_CONTROL);
  163. schedule_timeout_uninterruptible(msecs_to_jiffies(1));
  164. } while (retries-- && !(rtc_ctrl & WM8350_RTC_ALMSTS));
  165. if (!(rtc_ctrl & WM8350_RTC_ALMSTS))
  166. return -ETIMEDOUT;
  167. return 0;
  168. }
  169. static int wm8350_rtc_start_alarm(struct wm8350 *wm8350)
  170. {
  171. int ret;
  172. int retries = WM8350_SET_ALM_RETRIES;
  173. u16 rtc_ctrl;
  174. ret = wm8350_clear_bits(wm8350, WM8350_RTC_TIME_CONTROL,
  175. WM8350_RTC_ALMSET);
  176. if (ret < 0)
  177. return ret;
  178. /* Wait until confirmation */
  179. do {
  180. rtc_ctrl = wm8350_reg_read(wm8350, WM8350_RTC_TIME_CONTROL);
  181. schedule_timeout_uninterruptible(msecs_to_jiffies(1));
  182. } while (retries-- && rtc_ctrl & WM8350_RTC_ALMSTS);
  183. if (rtc_ctrl & WM8350_RTC_ALMSTS)
  184. return -ETIMEDOUT;
  185. return 0;
  186. }
  187. static int wm8350_rtc_alarm_irq_enable(struct device *dev,
  188. unsigned int enabled)
  189. {
  190. struct wm8350 *wm8350 = dev_get_drvdata(dev);
  191. if (enabled)
  192. return wm8350_rtc_start_alarm(wm8350);
  193. else
  194. return wm8350_rtc_stop_alarm(wm8350);
  195. }
  196. static int wm8350_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
  197. {
  198. struct wm8350 *wm8350 = dev_get_drvdata(dev);
  199. struct rtc_time *tm = &alrm->time;
  200. u16 time[3];
  201. int ret;
  202. memset(time, 0, sizeof(time));
  203. if (tm->tm_sec != -1)
  204. time[0] |= tm->tm_sec;
  205. else
  206. time[0] |= WM8350_RTC_ALMSECS_MASK;
  207. if (tm->tm_min != -1)
  208. time[0] |= tm->tm_min << WM8350_RTC_ALMMINS_SHIFT;
  209. else
  210. time[0] |= WM8350_RTC_ALMMINS_MASK;
  211. if (tm->tm_hour != -1)
  212. time[1] |= tm->tm_hour;
  213. else
  214. time[1] |= WM8350_RTC_ALMHRS_MASK;
  215. if (tm->tm_wday != -1)
  216. time[1] |= (tm->tm_wday + 1) << WM8350_RTC_ALMDAY_SHIFT;
  217. else
  218. time[1] |= WM8350_RTC_ALMDAY_MASK;
  219. if (tm->tm_mday != -1)
  220. time[2] |= tm->tm_mday;
  221. else
  222. time[2] |= WM8350_RTC_ALMDATE_MASK;
  223. if (tm->tm_mon != -1)
  224. time[2] |= (tm->tm_mon + 1) << WM8350_RTC_ALMMTH_SHIFT;
  225. else
  226. time[2] |= WM8350_RTC_ALMMTH_MASK;
  227. ret = wm8350_rtc_stop_alarm(wm8350);
  228. if (ret < 0)
  229. return ret;
  230. /* Write time to RTC */
  231. ret = wm8350_block_write(wm8350, WM8350_ALARM_SECONDS_MINUTES,
  232. 3, time);
  233. if (ret < 0)
  234. return ret;
  235. if (alrm->enabled)
  236. ret = wm8350_rtc_start_alarm(wm8350);
  237. return ret;
  238. }
  239. static irqreturn_t wm8350_rtc_alarm_handler(int irq, void *data)
  240. {
  241. struct wm8350 *wm8350 = data;
  242. struct rtc_device *rtc = wm8350->rtc.rtc;
  243. int ret;
  244. rtc_update_irq(rtc, 1, RTC_IRQF | RTC_AF);
  245. /* Make it one shot */
  246. ret = wm8350_set_bits(wm8350, WM8350_RTC_TIME_CONTROL,
  247. WM8350_RTC_ALMSET);
  248. if (ret != 0) {
  249. dev_err(&(wm8350->rtc.pdev->dev),
  250. "Failed to disable alarm: %d\n", ret);
  251. }
  252. return IRQ_HANDLED;
  253. }
  254. static irqreturn_t wm8350_rtc_update_handler(int irq, void *data)
  255. {
  256. struct wm8350 *wm8350 = data;
  257. struct rtc_device *rtc = wm8350->rtc.rtc;
  258. rtc_update_irq(rtc, 1, RTC_IRQF | RTC_UF);
  259. return IRQ_HANDLED;
  260. }
  261. static const struct rtc_class_ops wm8350_rtc_ops = {
  262. .read_time = wm8350_rtc_readtime,
  263. .set_time = wm8350_rtc_settime,
  264. .read_alarm = wm8350_rtc_readalarm,
  265. .set_alarm = wm8350_rtc_setalarm,
  266. .alarm_irq_enable = wm8350_rtc_alarm_irq_enable,
  267. };
  268. #ifdef CONFIG_PM_SLEEP
  269. static int wm8350_rtc_suspend(struct device *dev)
  270. {
  271. struct wm8350 *wm8350 = dev_get_drvdata(dev);
  272. int ret = 0;
  273. u16 reg;
  274. reg = wm8350_reg_read(wm8350, WM8350_RTC_TIME_CONTROL);
  275. if (device_may_wakeup(&wm8350->rtc.pdev->dev) &&
  276. reg & WM8350_RTC_ALMSTS) {
  277. ret = wm8350_rtc_stop_alarm(wm8350);
  278. if (ret != 0)
  279. dev_err(dev, "Failed to stop RTC alarm: %d\n", ret);
  280. }
  281. return ret;
  282. }
  283. static int wm8350_rtc_resume(struct device *dev)
  284. {
  285. struct wm8350 *wm8350 = dev_get_drvdata(dev);
  286. int ret;
  287. if (wm8350->rtc.alarm_enabled) {
  288. ret = wm8350_rtc_start_alarm(wm8350);
  289. if (ret != 0)
  290. dev_err(dev, "Failed to restart RTC alarm: %d\n", ret);
  291. }
  292. return 0;
  293. }
  294. #endif
  295. static int wm8350_rtc_probe(struct platform_device *pdev)
  296. {
  297. struct wm8350 *wm8350 = platform_get_drvdata(pdev);
  298. struct wm8350_rtc *wm_rtc = &wm8350->rtc;
  299. int ret = 0;
  300. u16 timectl, power5;
  301. timectl = wm8350_reg_read(wm8350, WM8350_RTC_TIME_CONTROL);
  302. if (timectl & WM8350_RTC_BCD) {
  303. dev_err(&pdev->dev, "RTC BCD mode not supported\n");
  304. return -EINVAL;
  305. }
  306. if (timectl & WM8350_RTC_12HR) {
  307. dev_err(&pdev->dev, "RTC 12 hour mode not supported\n");
  308. return -EINVAL;
  309. }
  310. /* enable the RTC if it's not already enabled */
  311. power5 = wm8350_reg_read(wm8350, WM8350_POWER_MGMT_5);
  312. if (!(power5 & WM8350_RTC_TICK_ENA)) {
  313. dev_info(wm8350->dev, "Starting RTC\n");
  314. wm8350_reg_unlock(wm8350);
  315. ret = wm8350_set_bits(wm8350, WM8350_POWER_MGMT_5,
  316. WM8350_RTC_TICK_ENA);
  317. if (ret < 0) {
  318. dev_err(&pdev->dev, "failed to enable RTC: %d\n", ret);
  319. return ret;
  320. }
  321. wm8350_reg_lock(wm8350);
  322. }
  323. if (timectl & WM8350_RTC_STS) {
  324. int retries;
  325. ret = wm8350_clear_bits(wm8350, WM8350_RTC_TIME_CONTROL,
  326. WM8350_RTC_SET);
  327. if (ret < 0) {
  328. dev_err(&pdev->dev, "failed to start: %d\n", ret);
  329. return ret;
  330. }
  331. retries = WM8350_SET_TIME_RETRIES;
  332. do {
  333. timectl = wm8350_reg_read(wm8350,
  334. WM8350_RTC_TIME_CONTROL);
  335. } while (timectl & WM8350_RTC_STS && --retries);
  336. if (retries == 0) {
  337. dev_err(&pdev->dev, "failed to start: timeout\n");
  338. return -ENODEV;
  339. }
  340. }
  341. device_init_wakeup(&pdev->dev, 1);
  342. wm_rtc->rtc = devm_rtc_device_register(&pdev->dev, "wm8350",
  343. &wm8350_rtc_ops, THIS_MODULE);
  344. if (IS_ERR(wm_rtc->rtc)) {
  345. ret = PTR_ERR(wm_rtc->rtc);
  346. dev_err(&pdev->dev, "failed to register RTC: %d\n", ret);
  347. return ret;
  348. }
  349. ret = wm8350_register_irq(wm8350, WM8350_IRQ_RTC_SEC,
  350. wm8350_rtc_update_handler, 0,
  351. "RTC Seconds", wm8350);
  352. if (ret)
  353. return ret;
  354. wm8350_mask_irq(wm8350, WM8350_IRQ_RTC_SEC);
  355. ret = wm8350_register_irq(wm8350, WM8350_IRQ_RTC_ALM,
  356. wm8350_rtc_alarm_handler, 0,
  357. "RTC Alarm", wm8350);
  358. if (ret) {
  359. wm8350_free_irq(wm8350, WM8350_IRQ_RTC_SEC, wm8350);
  360. return ret;
  361. }
  362. return 0;
  363. }
  364. static int wm8350_rtc_remove(struct platform_device *pdev)
  365. {
  366. struct wm8350 *wm8350 = platform_get_drvdata(pdev);
  367. wm8350_free_irq(wm8350, WM8350_IRQ_RTC_SEC, wm8350);
  368. wm8350_free_irq(wm8350, WM8350_IRQ_RTC_ALM, wm8350);
  369. return 0;
  370. }
  371. static SIMPLE_DEV_PM_OPS(wm8350_rtc_pm_ops, wm8350_rtc_suspend,
  372. wm8350_rtc_resume);
  373. static struct platform_driver wm8350_rtc_driver = {
  374. .probe = wm8350_rtc_probe,
  375. .remove = wm8350_rtc_remove,
  376. .driver = {
  377. .name = "wm8350-rtc",
  378. .pm = &wm8350_rtc_pm_ops,
  379. },
  380. };
  381. module_platform_driver(wm8350_rtc_driver);
  382. MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
  383. MODULE_DESCRIPTION("RTC driver for the WM8350");
  384. MODULE_LICENSE("GPL");
  385. MODULE_ALIAS("platform:wm8350-rtc");