rtc-rk808.c 13 KB

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  1. // SPDX-License-Identifier: GPL-2.0-only
  2. /*
  3. * RTC driver for Rockchip RK808
  4. *
  5. * Copyright (c) 2014, Fuzhou Rockchip Electronics Co., Ltd
  6. *
  7. * Author: Chris Zhong <zyw@rock-chips.com>
  8. * Author: Zhang Qing <zhangqing@rock-chips.com>
  9. */
  10. #include <linux/module.h>
  11. #include <linux/kernel.h>
  12. #include <linux/rtc.h>
  13. #include <linux/bcd.h>
  14. #include <linux/mfd/rk808.h>
  15. #include <linux/platform_device.h>
  16. #include <linux/i2c.h>
  17. /* RTC_CTRL_REG bitfields */
  18. #define BIT_RTC_CTRL_REG_STOP_RTC_M BIT(0)
  19. /* RK808 has a shadowed register for saving a "frozen" RTC time.
  20. * When user setting "GET_TIME" to 1, the time will save in this shadowed
  21. * register. If set "READSEL" to 1, user read rtc time register, actually
  22. * get the time of that moment. If we need the real time, clr this bit.
  23. */
  24. #define BIT_RTC_CTRL_REG_RTC_GET_TIME BIT(6)
  25. #define BIT_RTC_CTRL_REG_RTC_READSEL_M BIT(7)
  26. #define BIT_RTC_INTERRUPTS_REG_IT_ALARM_M BIT(3)
  27. #define RTC_STATUS_MASK 0xFE
  28. #define SECONDS_REG_MSK 0x7F
  29. #define MINUTES_REG_MAK 0x7F
  30. #define HOURS_REG_MSK 0x3F
  31. #define DAYS_REG_MSK 0x3F
  32. #define MONTHS_REG_MSK 0x1F
  33. #define YEARS_REG_MSK 0xFF
  34. #define WEEKS_REG_MSK 0x7
  35. /* REG_SECONDS_REG through REG_YEARS_REG is how many registers? */
  36. #define NUM_TIME_REGS (RK808_WEEKS_REG - RK808_SECONDS_REG + 1)
  37. #define NUM_ALARM_REGS (RK808_ALARM_YEARS_REG - RK808_ALARM_SECONDS_REG + 1)
  38. struct rk_rtc_compat_reg {
  39. unsigned int ctrl_reg;
  40. unsigned int status_reg;
  41. unsigned int alarm_seconds_reg;
  42. unsigned int int_reg;
  43. unsigned int seconds_reg;
  44. };
  45. struct rk808_rtc {
  46. struct rk808 *rk808;
  47. struct rtc_device *rtc;
  48. struct rk_rtc_compat_reg *creg;
  49. int irq;
  50. };
  51. /*
  52. * The Rockchip calendar used by the RK808 counts November with 31 days. We use
  53. * these translation functions to convert its dates to/from the Gregorian
  54. * calendar used by the rest of the world. We arbitrarily define Jan 1st, 2016
  55. * as the day when both calendars were in sync, and treat all other dates
  56. * relative to that.
  57. * NOTE: Other system software (e.g. firmware) that reads the same hardware must
  58. * implement this exact same conversion algorithm, with the same anchor date.
  59. */
  60. static time64_t nov2dec_transitions(struct rtc_time *tm)
  61. {
  62. return (tm->tm_year + 1900) - 2016 + (tm->tm_mon + 1 > 11 ? 1 : 0);
  63. }
  64. static void rockchip_to_gregorian(struct rtc_time *tm)
  65. {
  66. /* If it's Nov 31st, rtc_tm_to_time64() will count that like Dec 1st */
  67. time64_t time = rtc_tm_to_time64(tm);
  68. rtc_time64_to_tm(time + nov2dec_transitions(tm) * 86400, tm);
  69. }
  70. static void gregorian_to_rockchip(struct rtc_time *tm)
  71. {
  72. time64_t extra_days = nov2dec_transitions(tm);
  73. time64_t time = rtc_tm_to_time64(tm);
  74. rtc_time64_to_tm(time - extra_days * 86400, tm);
  75. /* Compensate if we went back over Nov 31st (will work up to 2381) */
  76. if (nov2dec_transitions(tm) < extra_days) {
  77. if (tm->tm_mon + 1 == 11)
  78. tm->tm_mday++; /* This may result in 31! */
  79. else
  80. rtc_time64_to_tm(time - (extra_days - 1) * 86400, tm);
  81. }
  82. }
  83. /* Read current time and date in RTC */
  84. static int rk808_rtc_readtime(struct device *dev, struct rtc_time *tm)
  85. {
  86. struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
  87. struct rk808 *rk808 = rk808_rtc->rk808;
  88. u8 rtc_data[NUM_TIME_REGS];
  89. int ret;
  90. /* Force an update of the shadowed registers right now */
  91. ret = regmap_update_bits(rk808->regmap, rk808_rtc->creg->ctrl_reg,
  92. BIT_RTC_CTRL_REG_RTC_GET_TIME,
  93. BIT_RTC_CTRL_REG_RTC_GET_TIME);
  94. if (ret) {
  95. dev_err(dev, "Failed to update bits rtc_ctrl: %d\n", ret);
  96. return ret;
  97. }
  98. /*
  99. * After we set the GET_TIME bit, the rtc time can't be read
  100. * immediately. So we should wait up to 31.25 us, about one cycle of
  101. * 32khz. If we clear the GET_TIME bit here, the time of i2c transfer
  102. * certainly more than 31.25us: 16 * 2.5us at 400kHz bus frequency.
  103. */
  104. ret = regmap_update_bits(rk808->regmap, rk808_rtc->creg->ctrl_reg,
  105. BIT_RTC_CTRL_REG_RTC_GET_TIME,
  106. 0);
  107. if (ret) {
  108. dev_err(dev, "Failed to update bits rtc_ctrl: %d\n", ret);
  109. return ret;
  110. }
  111. ret = regmap_bulk_read(rk808->regmap, rk808_rtc->creg->seconds_reg,
  112. rtc_data, NUM_TIME_REGS);
  113. if (ret) {
  114. dev_err(dev, "Failed to bulk read rtc_data: %d\n", ret);
  115. return ret;
  116. }
  117. tm->tm_sec = bcd2bin(rtc_data[0] & SECONDS_REG_MSK);
  118. tm->tm_min = bcd2bin(rtc_data[1] & MINUTES_REG_MAK);
  119. tm->tm_hour = bcd2bin(rtc_data[2] & HOURS_REG_MSK);
  120. tm->tm_mday = bcd2bin(rtc_data[3] & DAYS_REG_MSK);
  121. tm->tm_mon = (bcd2bin(rtc_data[4] & MONTHS_REG_MSK)) - 1;
  122. tm->tm_year = (bcd2bin(rtc_data[5] & YEARS_REG_MSK)) + 100;
  123. tm->tm_wday = bcd2bin(rtc_data[6] & WEEKS_REG_MSK);
  124. rockchip_to_gregorian(tm);
  125. dev_dbg(dev, "RTC date/time %ptRd(%d) %ptRt\n", tm, tm->tm_wday, tm);
  126. return ret;
  127. }
  128. /* Set current time and date in RTC */
  129. static int rk808_rtc_set_time(struct device *dev, struct rtc_time *tm)
  130. {
  131. struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
  132. struct rk808 *rk808 = rk808_rtc->rk808;
  133. u8 rtc_data[NUM_TIME_REGS];
  134. int ret;
  135. dev_dbg(dev, "set RTC date/time %ptRd(%d) %ptRt\n", tm, tm->tm_wday, tm);
  136. gregorian_to_rockchip(tm);
  137. rtc_data[0] = bin2bcd(tm->tm_sec);
  138. rtc_data[1] = bin2bcd(tm->tm_min);
  139. rtc_data[2] = bin2bcd(tm->tm_hour);
  140. rtc_data[3] = bin2bcd(tm->tm_mday);
  141. rtc_data[4] = bin2bcd(tm->tm_mon + 1);
  142. rtc_data[5] = bin2bcd(tm->tm_year - 100);
  143. rtc_data[6] = bin2bcd(tm->tm_wday);
  144. /* Stop RTC while updating the RTC registers */
  145. ret = regmap_update_bits(rk808->regmap, rk808_rtc->creg->ctrl_reg,
  146. BIT_RTC_CTRL_REG_STOP_RTC_M,
  147. BIT_RTC_CTRL_REG_STOP_RTC_M);
  148. if (ret) {
  149. dev_err(dev, "Failed to update RTC control: %d\n", ret);
  150. return ret;
  151. }
  152. ret = regmap_bulk_write(rk808->regmap, rk808_rtc->creg->seconds_reg,
  153. rtc_data, NUM_TIME_REGS);
  154. if (ret) {
  155. dev_err(dev, "Failed to bull write rtc_data: %d\n", ret);
  156. return ret;
  157. }
  158. /* Start RTC again */
  159. ret = regmap_update_bits(rk808->regmap, rk808_rtc->creg->ctrl_reg,
  160. BIT_RTC_CTRL_REG_STOP_RTC_M, 0);
  161. if (ret) {
  162. dev_err(dev, "Failed to update RTC control: %d\n", ret);
  163. return ret;
  164. }
  165. return 0;
  166. }
  167. /* Read alarm time and date in RTC */
  168. static int rk808_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
  169. {
  170. struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
  171. struct rk808 *rk808 = rk808_rtc->rk808;
  172. u8 alrm_data[NUM_ALARM_REGS];
  173. uint32_t int_reg;
  174. int ret;
  175. ret = regmap_bulk_read(rk808->regmap,
  176. rk808_rtc->creg->alarm_seconds_reg,
  177. alrm_data, NUM_ALARM_REGS);
  178. if (ret) {
  179. dev_err(dev, "Failed to read RTC alarm date REG: %d\n", ret);
  180. return ret;
  181. }
  182. alrm->time.tm_sec = bcd2bin(alrm_data[0] & SECONDS_REG_MSK);
  183. alrm->time.tm_min = bcd2bin(alrm_data[1] & MINUTES_REG_MAK);
  184. alrm->time.tm_hour = bcd2bin(alrm_data[2] & HOURS_REG_MSK);
  185. alrm->time.tm_mday = bcd2bin(alrm_data[3] & DAYS_REG_MSK);
  186. alrm->time.tm_mon = (bcd2bin(alrm_data[4] & MONTHS_REG_MSK)) - 1;
  187. alrm->time.tm_year = (bcd2bin(alrm_data[5] & YEARS_REG_MSK)) + 100;
  188. rockchip_to_gregorian(&alrm->time);
  189. ret = regmap_read(rk808->regmap, rk808_rtc->creg->int_reg, &int_reg);
  190. if (ret) {
  191. dev_err(dev, "Failed to read RTC INT REG: %d\n", ret);
  192. return ret;
  193. }
  194. dev_dbg(dev, "alrm read RTC date/time %ptRd(%d) %ptRt\n",
  195. &alrm->time, alrm->time.tm_wday, &alrm->time);
  196. alrm->enabled = (int_reg & BIT_RTC_INTERRUPTS_REG_IT_ALARM_M) ? 1 : 0;
  197. return 0;
  198. }
  199. static int rk808_rtc_stop_alarm(struct rk808_rtc *rk808_rtc)
  200. {
  201. struct rk808 *rk808 = rk808_rtc->rk808;
  202. int ret;
  203. ret = regmap_update_bits(rk808->regmap, rk808_rtc->creg->int_reg,
  204. BIT_RTC_INTERRUPTS_REG_IT_ALARM_M, 0);
  205. return ret;
  206. }
  207. static int rk808_rtc_start_alarm(struct rk808_rtc *rk808_rtc)
  208. {
  209. struct rk808 *rk808 = rk808_rtc->rk808;
  210. int ret;
  211. ret = regmap_update_bits(rk808->regmap, rk808_rtc->creg->int_reg,
  212. BIT_RTC_INTERRUPTS_REG_IT_ALARM_M,
  213. BIT_RTC_INTERRUPTS_REG_IT_ALARM_M);
  214. return ret;
  215. }
  216. static int rk808_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
  217. {
  218. struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
  219. struct rk808 *rk808 = rk808_rtc->rk808;
  220. u8 alrm_data[NUM_ALARM_REGS];
  221. int ret;
  222. ret = rk808_rtc_stop_alarm(rk808_rtc);
  223. if (ret) {
  224. dev_err(dev, "Failed to stop alarm: %d\n", ret);
  225. return ret;
  226. }
  227. dev_dbg(dev, "alrm set RTC date/time %ptRd(%d) %ptRt\n",
  228. &alrm->time, alrm->time.tm_wday, &alrm->time);
  229. gregorian_to_rockchip(&alrm->time);
  230. alrm_data[0] = bin2bcd(alrm->time.tm_sec);
  231. alrm_data[1] = bin2bcd(alrm->time.tm_min);
  232. alrm_data[2] = bin2bcd(alrm->time.tm_hour);
  233. alrm_data[3] = bin2bcd(alrm->time.tm_mday);
  234. alrm_data[4] = bin2bcd(alrm->time.tm_mon + 1);
  235. alrm_data[5] = bin2bcd(alrm->time.tm_year - 100);
  236. ret = regmap_bulk_write(rk808->regmap,
  237. rk808_rtc->creg->alarm_seconds_reg,
  238. alrm_data, NUM_ALARM_REGS);
  239. if (ret) {
  240. dev_err(dev, "Failed to bulk write: %d\n", ret);
  241. return ret;
  242. }
  243. if (alrm->enabled) {
  244. ret = rk808_rtc_start_alarm(rk808_rtc);
  245. if (ret) {
  246. dev_err(dev, "Failed to start alarm: %d\n", ret);
  247. return ret;
  248. }
  249. }
  250. return 0;
  251. }
  252. static int rk808_rtc_alarm_irq_enable(struct device *dev,
  253. unsigned int enabled)
  254. {
  255. struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
  256. if (enabled)
  257. return rk808_rtc_start_alarm(rk808_rtc);
  258. return rk808_rtc_stop_alarm(rk808_rtc);
  259. }
  260. /*
  261. * We will just handle setting the frequency and make use the framework for
  262. * reading the periodic interupts.
  263. *
  264. * @freq: Current periodic IRQ freq:
  265. * bit 0: every second
  266. * bit 1: every minute
  267. * bit 2: every hour
  268. * bit 3: every day
  269. */
  270. static irqreturn_t rk808_alarm_irq(int irq, void *data)
  271. {
  272. struct rk808_rtc *rk808_rtc = data;
  273. struct rk808 *rk808 = rk808_rtc->rk808;
  274. struct i2c_client *client = rk808->i2c;
  275. int ret;
  276. ret = regmap_write(rk808->regmap, rk808_rtc->creg->status_reg,
  277. RTC_STATUS_MASK);
  278. if (ret) {
  279. dev_err(&client->dev,
  280. "%s:Failed to update RTC status: %d\n", __func__, ret);
  281. return ret;
  282. }
  283. rtc_update_irq(rk808_rtc->rtc, 1, RTC_IRQF | RTC_AF);
  284. dev_dbg(&client->dev,
  285. "%s:irq=%d\n", __func__, irq);
  286. return IRQ_HANDLED;
  287. }
  288. static const struct rtc_class_ops rk808_rtc_ops = {
  289. .read_time = rk808_rtc_readtime,
  290. .set_time = rk808_rtc_set_time,
  291. .read_alarm = rk808_rtc_readalarm,
  292. .set_alarm = rk808_rtc_setalarm,
  293. .alarm_irq_enable = rk808_rtc_alarm_irq_enable,
  294. };
  295. #ifdef CONFIG_PM_SLEEP
  296. /* Turn off the alarm if it should not be a wake source. */
  297. static int rk808_rtc_suspend(struct device *dev)
  298. {
  299. struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
  300. if (device_may_wakeup(dev))
  301. enable_irq_wake(rk808_rtc->irq);
  302. return 0;
  303. }
  304. /* Enable the alarm if it should be enabled (in case it was disabled to
  305. * prevent use as a wake source).
  306. */
  307. static int rk808_rtc_resume(struct device *dev)
  308. {
  309. struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
  310. if (device_may_wakeup(dev))
  311. disable_irq_wake(rk808_rtc->irq);
  312. return 0;
  313. }
  314. #endif
  315. static SIMPLE_DEV_PM_OPS(rk808_rtc_pm_ops,
  316. rk808_rtc_suspend, rk808_rtc_resume);
  317. static struct rk_rtc_compat_reg rk808_creg = {
  318. .ctrl_reg = RK808_RTC_CTRL_REG,
  319. .status_reg = RK808_RTC_STATUS_REG,
  320. .alarm_seconds_reg = RK808_ALARM_SECONDS_REG,
  321. .int_reg = RK808_RTC_INT_REG,
  322. .seconds_reg = RK808_SECONDS_REG,
  323. };
  324. static struct rk_rtc_compat_reg rk817_creg = {
  325. .ctrl_reg = RK817_RTC_CTRL_REG,
  326. .status_reg = RK817_RTC_STATUS_REG,
  327. .alarm_seconds_reg = RK817_ALARM_SECONDS_REG,
  328. .int_reg = RK817_RTC_INT_REG,
  329. .seconds_reg = RK817_SECONDS_REG,
  330. };
  331. static int rk808_rtc_probe(struct platform_device *pdev)
  332. {
  333. struct rk808 *rk808 = dev_get_drvdata(pdev->dev.parent);
  334. struct rk808_rtc *rk808_rtc;
  335. int ret;
  336. rk808_rtc = devm_kzalloc(&pdev->dev, sizeof(*rk808_rtc), GFP_KERNEL);
  337. if (rk808_rtc == NULL)
  338. return -ENOMEM;
  339. switch (rk808->variant) {
  340. case RK809_ID:
  341. case RK817_ID:
  342. rk808_rtc->creg = &rk817_creg;
  343. break;
  344. default:
  345. rk808_rtc->creg = &rk808_creg;
  346. break;
  347. }
  348. platform_set_drvdata(pdev, rk808_rtc);
  349. rk808_rtc->rk808 = rk808;
  350. /* start rtc running by default, and use shadowed timer. */
  351. ret = regmap_update_bits(rk808->regmap, rk808_rtc->creg->ctrl_reg,
  352. BIT_RTC_CTRL_REG_STOP_RTC_M |
  353. BIT_RTC_CTRL_REG_RTC_READSEL_M,
  354. BIT_RTC_CTRL_REG_RTC_READSEL_M);
  355. if (ret) {
  356. dev_err(&pdev->dev,
  357. "Failed to update RTC control: %d\n", ret);
  358. return ret;
  359. }
  360. ret = regmap_write(rk808->regmap, rk808_rtc->creg->status_reg,
  361. RTC_STATUS_MASK);
  362. if (ret) {
  363. dev_err(&pdev->dev,
  364. "Failed to write RTC status: %d\n", ret);
  365. return ret;
  366. }
  367. device_init_wakeup(&pdev->dev, 1);
  368. rk808_rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
  369. if (IS_ERR(rk808_rtc->rtc))
  370. return PTR_ERR(rk808_rtc->rtc);
  371. rk808_rtc->rtc->ops = &rk808_rtc_ops;
  372. rk808_rtc->irq = platform_get_irq(pdev, 0);
  373. if (rk808_rtc->irq < 0)
  374. return rk808_rtc->irq;
  375. /* request alarm irq of rk808 */
  376. ret = devm_request_threaded_irq(&pdev->dev, rk808_rtc->irq, NULL,
  377. rk808_alarm_irq, 0,
  378. "RTC alarm", rk808_rtc);
  379. if (ret) {
  380. dev_err(&pdev->dev, "Failed to request alarm IRQ %d: %d\n",
  381. rk808_rtc->irq, ret);
  382. return ret;
  383. }
  384. return rtc_register_device(rk808_rtc->rtc);
  385. }
  386. static struct platform_driver rk808_rtc_driver = {
  387. .probe = rk808_rtc_probe,
  388. .driver = {
  389. .name = "rk808-rtc",
  390. .pm = &rk808_rtc_pm_ops,
  391. },
  392. };
  393. module_platform_driver(rk808_rtc_driver);
  394. MODULE_DESCRIPTION("RTC driver for the rk808 series PMICs");
  395. MODULE_AUTHOR("Chris Zhong <zyw@rock-chips.com>");
  396. MODULE_AUTHOR("Zhang Qing <zhangqing@rock-chips.com>");
  397. MODULE_LICENSE("GPL");
  398. MODULE_ALIAS("platform:rk808-rtc");