2 * Real Time Clock driver for Wolfson Microelectronics WM831x
4 * Copyright (C) 2009 Wolfson Microelectronics PLC.
6 * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License as published by the
10 * Free Software Foundation; either version 2 of the License, or (at your
11 * option) any later version.
15 #include <linux/module.h>
16 #include <linux/kernel.h>
17 #include <linux/time.h>
18 #include <linux/rtc.h>
19 #include <linux/bcd.h>
20 #include <linux/interrupt.h>
21 #include <linux/ioctl.h>
22 #include <linux/completion.h>
23 #include <linux/mfd/wm831x/core.h>
24 #include <linux/delay.h>
25 #include <linux/platform_device.h>
29 * R16416 (0x4020) - RTC Write Counter
31 #define WM831X_RTC_WR_CNT_MASK 0xFFFF /* RTC_WR_CNT - [15:0] */
32 #define WM831X_RTC_WR_CNT_SHIFT 0 /* RTC_WR_CNT - [15:0] */
33 #define WM831X_RTC_WR_CNT_WIDTH 16 /* RTC_WR_CNT - [15:0] */
36 * R16417 (0x4021) - RTC Time 1
38 #define WM831X_RTC_TIME_MASK 0xFFFF /* RTC_TIME - [15:0] */
39 #define WM831X_RTC_TIME_SHIFT 0 /* RTC_TIME - [15:0] */
40 #define WM831X_RTC_TIME_WIDTH 16 /* RTC_TIME - [15:0] */
43 * R16418 (0x4022) - RTC Time 2
45 #define WM831X_RTC_TIME_MASK 0xFFFF /* RTC_TIME - [15:0] */
46 #define WM831X_RTC_TIME_SHIFT 0 /* RTC_TIME - [15:0] */
47 #define WM831X_RTC_TIME_WIDTH 16 /* RTC_TIME - [15:0] */
50 * R16419 (0x4023) - RTC Alarm 1
52 #define WM831X_RTC_ALM_MASK 0xFFFF /* RTC_ALM - [15:0] */
53 #define WM831X_RTC_ALM_SHIFT 0 /* RTC_ALM - [15:0] */
54 #define WM831X_RTC_ALM_WIDTH 16 /* RTC_ALM - [15:0] */
57 * R16420 (0x4024) - RTC Alarm 2
59 #define WM831X_RTC_ALM_MASK 0xFFFF /* RTC_ALM - [15:0] */
60 #define WM831X_RTC_ALM_SHIFT 0 /* RTC_ALM - [15:0] */
61 #define WM831X_RTC_ALM_WIDTH 16 /* RTC_ALM - [15:0] */
64 * R16421 (0x4025) - RTC Control
66 #define WM831X_RTC_VALID 0x8000 /* RTC_VALID */
67 #define WM831X_RTC_VALID_MASK 0x8000 /* RTC_VALID */
68 #define WM831X_RTC_VALID_SHIFT 15 /* RTC_VALID */
69 #define WM831X_RTC_VALID_WIDTH 1 /* RTC_VALID */
70 #define WM831X_RTC_SYNC_BUSY 0x4000 /* RTC_SYNC_BUSY */
71 #define WM831X_RTC_SYNC_BUSY_MASK 0x4000 /* RTC_SYNC_BUSY */
72 #define WM831X_RTC_SYNC_BUSY_SHIFT 14 /* RTC_SYNC_BUSY */
73 #define WM831X_RTC_SYNC_BUSY_WIDTH 1 /* RTC_SYNC_BUSY */
74 #define WM831X_RTC_ALM_ENA 0x0400 /* RTC_ALM_ENA */
75 #define WM831X_RTC_ALM_ENA_MASK 0x0400 /* RTC_ALM_ENA */
76 #define WM831X_RTC_ALM_ENA_SHIFT 10 /* RTC_ALM_ENA */
77 #define WM831X_RTC_ALM_ENA_WIDTH 1 /* RTC_ALM_ENA */
78 #define WM831X_RTC_PINT_FREQ_MASK 0x0070 /* RTC_PINT_FREQ - [6:4] */
79 #define WM831X_RTC_PINT_FREQ_SHIFT 4 /* RTC_PINT_FREQ - [6:4] */
80 #define WM831X_RTC_PINT_FREQ_WIDTH 3 /* RTC_PINT_FREQ - [6:4] */
83 * R16422 (0x4026) - RTC Trim
85 #define WM831X_RTC_TRIM_MASK 0x03FF /* RTC_TRIM - [9:0] */
86 #define WM831X_RTC_TRIM_SHIFT 0 /* RTC_TRIM - [9:0] */
87 #define WM831X_RTC_TRIM_WIDTH 10 /* RTC_TRIM - [9:0] */
89 #define WM831X_SET_TIME_RETRIES 5
90 #define WM831X_GET_TIME_RETRIES 5
93 struct wm831x *wm831x;
94 struct rtc_device *rtc;
95 unsigned int alarm_enabled:1;
99 * Read current time and date in RTC
101 static int wm831x_rtc_readtime(struct device *dev, struct rtc_time *tm)
103 struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev);
104 struct wm831x *wm831x = wm831x_rtc->wm831x;
105 u16 time1[2], time2[2];
109 /* Has the RTC been programmed? */
110 ret = wm831x_reg_read(wm831x, WM831X_RTC_CONTROL);
112 dev_err(dev, "Failed to read RTC control: %d\n", ret);
115 if (!(ret & WM831X_RTC_VALID)) {
116 dev_dbg(dev, "RTC not yet configured\n");
120 /* Read twice to make sure we don't read a corrupt, partially
121 * incremented, value.
124 ret = wm831x_bulk_read(wm831x, WM831X_RTC_TIME_1,
129 ret = wm831x_bulk_read(wm831x, WM831X_RTC_TIME_1,
134 if (memcmp(time1, time2, sizeof(time1)) == 0) {
135 u32 time = (time1[0] << 16) | time1[1];
137 rtc_time_to_tm(time, tm);
138 return rtc_valid_tm(tm);
141 } while (++count < WM831X_GET_TIME_RETRIES);
143 dev_err(dev, "Timed out reading current time\n");
149 * Set current time and date in RTC
151 static int wm831x_rtc_set_mmss(struct device *dev, unsigned long time)
153 struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev);
154 struct wm831x *wm831x = wm831x_rtc->wm831x;
155 struct rtc_time new_tm;
156 unsigned long new_time;
160 ret = wm831x_reg_write(wm831x, WM831X_RTC_TIME_1,
161 (time >> 16) & 0xffff);
163 dev_err(dev, "Failed to write TIME_1: %d\n", ret);
167 ret = wm831x_reg_write(wm831x, WM831X_RTC_TIME_2, time & 0xffff);
169 dev_err(dev, "Failed to write TIME_2: %d\n", ret);
173 /* Wait for the update to complete - should happen first time
174 * round but be conservative.
179 ret = wm831x_reg_read(wm831x, WM831X_RTC_CONTROL);
181 ret = WM831X_RTC_SYNC_BUSY;
182 } while (!(ret & WM831X_RTC_SYNC_BUSY) &&
183 ++count < WM831X_SET_TIME_RETRIES);
185 if (ret & WM831X_RTC_SYNC_BUSY) {
186 dev_err(dev, "Timed out writing RTC update\n");
190 /* Check that the update was accepted; security features may
191 * have caused the update to be ignored.
193 ret = wm831x_rtc_readtime(dev, &new_tm);
197 ret = rtc_tm_to_time(&new_tm, &new_time);
199 dev_err(dev, "Failed to convert time: %d\n", ret);
203 /* Allow a second of change in case of tick */
204 if (new_time - time > 1) {
205 dev_err(dev, "RTC update not permitted by hardware\n");
213 * Read alarm time and date in RTC
215 static int wm831x_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
217 struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev);
222 ret = wm831x_bulk_read(wm831x_rtc->wm831x, WM831X_RTC_ALARM_1,
225 dev_err(dev, "Failed to read alarm time: %d\n", ret);
229 time = (data[0] << 16) | data[1];
231 rtc_time_to_tm(time, &alrm->time);
233 ret = wm831x_reg_read(wm831x_rtc->wm831x, WM831X_RTC_CONTROL);
235 dev_err(dev, "Failed to read RTC control: %d\n", ret);
239 if (ret & WM831X_RTC_ALM_ENA)
247 static int wm831x_rtc_stop_alarm(struct wm831x_rtc *wm831x_rtc)
249 wm831x_rtc->alarm_enabled = 0;
251 return wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL,
252 WM831X_RTC_ALM_ENA, 0);
255 static int wm831x_rtc_start_alarm(struct wm831x_rtc *wm831x_rtc)
257 wm831x_rtc->alarm_enabled = 1;
259 return wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL,
260 WM831X_RTC_ALM_ENA, WM831X_RTC_ALM_ENA);
263 static int wm831x_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
265 struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev);
266 struct wm831x *wm831x = wm831x_rtc->wm831x;
270 ret = rtc_tm_to_time(&alrm->time, &time);
272 dev_err(dev, "Failed to convert time: %d\n", ret);
276 ret = wm831x_rtc_stop_alarm(wm831x_rtc);
278 dev_err(dev, "Failed to stop alarm: %d\n", ret);
282 ret = wm831x_reg_write(wm831x, WM831X_RTC_ALARM_1,
283 (time >> 16) & 0xffff);
285 dev_err(dev, "Failed to write ALARM_1: %d\n", ret);
289 ret = wm831x_reg_write(wm831x, WM831X_RTC_ALARM_2, time & 0xffff);
291 dev_err(dev, "Failed to write ALARM_2: %d\n", ret);
296 ret = wm831x_rtc_start_alarm(wm831x_rtc);
298 dev_err(dev, "Failed to start alarm: %d\n", ret);
306 static int wm831x_rtc_alarm_irq_enable(struct device *dev,
307 unsigned int enabled)
309 struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev);
312 return wm831x_rtc_start_alarm(wm831x_rtc);
314 return wm831x_rtc_stop_alarm(wm831x_rtc);
317 static int wm831x_rtc_update_irq_enable(struct device *dev,
318 unsigned int enabled)
320 struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev);
324 val = 1 << WM831X_RTC_PINT_FREQ_SHIFT;
328 return wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL,
329 WM831X_RTC_PINT_FREQ_MASK, val);
332 static irqreturn_t wm831x_alm_irq(int irq, void *data)
334 struct wm831x_rtc *wm831x_rtc = data;
336 rtc_update_irq(wm831x_rtc->rtc, 1, RTC_IRQF | RTC_AF);
341 static irqreturn_t wm831x_per_irq(int irq, void *data)
343 struct wm831x_rtc *wm831x_rtc = data;
345 rtc_update_irq(wm831x_rtc->rtc, 1, RTC_IRQF | RTC_UF);
350 static const struct rtc_class_ops wm831x_rtc_ops = {
351 .read_time = wm831x_rtc_readtime,
352 .set_mmss = wm831x_rtc_set_mmss,
353 .read_alarm = wm831x_rtc_readalarm,
354 .set_alarm = wm831x_rtc_setalarm,
355 .alarm_irq_enable = wm831x_rtc_alarm_irq_enable,
356 .update_irq_enable = wm831x_rtc_update_irq_enable,
360 /* Turn off the alarm if it should not be a wake source. */
361 static int wm831x_rtc_suspend(struct device *dev)
363 struct platform_device *pdev = to_platform_device(dev);
364 struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(&pdev->dev);
367 if (wm831x_rtc->alarm_enabled && device_may_wakeup(&pdev->dev))
368 enable = WM831X_RTC_ALM_ENA;
372 ret = wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL,
373 WM831X_RTC_ALM_ENA, enable);
375 dev_err(&pdev->dev, "Failed to update RTC alarm: %d\n", ret);
380 /* Enable the alarm if it should be enabled (in case it was disabled to
381 * prevent use as a wake source).
383 static int wm831x_rtc_resume(struct device *dev)
385 struct platform_device *pdev = to_platform_device(dev);
386 struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(&pdev->dev);
389 if (wm831x_rtc->alarm_enabled) {
390 ret = wm831x_rtc_start_alarm(wm831x_rtc);
393 "Failed to restart RTC alarm: %d\n", ret);
399 /* Unconditionally disable the alarm */
400 static int wm831x_rtc_freeze(struct device *dev)
402 struct platform_device *pdev = to_platform_device(dev);
403 struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(&pdev->dev);
406 ret = wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL,
407 WM831X_RTC_ALM_ENA, 0);
409 dev_err(&pdev->dev, "Failed to stop RTC alarm: %d\n", ret);
414 #define wm831x_rtc_suspend NULL
415 #define wm831x_rtc_resume NULL
416 #define wm831x_rtc_freeze NULL
419 static int wm831x_rtc_probe(struct platform_device *pdev)
421 struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
422 struct wm831x_rtc *wm831x_rtc;
423 int per_irq = platform_get_irq_byname(pdev, "PER");
424 int alm_irq = platform_get_irq_byname(pdev, "ALM");
427 wm831x_rtc = kzalloc(sizeof(*wm831x_rtc), GFP_KERNEL);
428 if (wm831x_rtc == NULL)
431 platform_set_drvdata(pdev, wm831x_rtc);
432 wm831x_rtc->wm831x = wm831x;
434 ret = wm831x_reg_read(wm831x, WM831X_RTC_CONTROL);
436 dev_err(&pdev->dev, "Failed to read RTC control: %d\n", ret);
439 if (ret & WM831X_RTC_ALM_ENA)
440 wm831x_rtc->alarm_enabled = 1;
442 device_init_wakeup(&pdev->dev, 1);
444 wm831x_rtc->rtc = rtc_device_register("wm831x", &pdev->dev,
445 &wm831x_rtc_ops, THIS_MODULE);
446 if (IS_ERR(wm831x_rtc->rtc)) {
447 ret = PTR_ERR(wm831x_rtc->rtc);
451 ret = wm831x_request_irq(wm831x, per_irq, wm831x_per_irq,
452 IRQF_TRIGGER_RISING, "wm831x_rtc_per",
455 dev_err(&pdev->dev, "Failed to request periodic IRQ %d: %d\n",
459 ret = wm831x_request_irq(wm831x, alm_irq, wm831x_alm_irq,
460 IRQF_TRIGGER_RISING, "wm831x_rtc_alm",
463 dev_err(&pdev->dev, "Failed to request alarm IRQ %d: %d\n",
474 static int __devexit wm831x_rtc_remove(struct platform_device *pdev)
476 struct wm831x_rtc *wm831x_rtc = platform_get_drvdata(pdev);
477 int per_irq = platform_get_irq_byname(pdev, "PER");
478 int alm_irq = platform_get_irq_byname(pdev, "ALM");
480 wm831x_free_irq(wm831x_rtc->wm831x, alm_irq, wm831x_rtc);
481 wm831x_free_irq(wm831x_rtc->wm831x, per_irq, wm831x_rtc);
482 rtc_device_unregister(wm831x_rtc->rtc);
488 static struct dev_pm_ops wm831x_rtc_pm_ops = {
489 .suspend = wm831x_rtc_suspend,
490 .resume = wm831x_rtc_resume,
492 .freeze = wm831x_rtc_freeze,
493 .thaw = wm831x_rtc_resume,
494 .restore = wm831x_rtc_resume,
496 .poweroff = wm831x_rtc_suspend,
499 static struct platform_driver wm831x_rtc_driver = {
500 .probe = wm831x_rtc_probe,
501 .remove = __devexit_p(wm831x_rtc_remove),
503 .name = "wm831x-rtc",
504 .pm = &wm831x_rtc_pm_ops,
508 static int __init wm831x_rtc_init(void)
510 return platform_driver_register(&wm831x_rtc_driver);
512 module_init(wm831x_rtc_init);
514 static void __exit wm831x_rtc_exit(void)
516 platform_driver_unregister(&wm831x_rtc_driver);
518 module_exit(wm831x_rtc_exit);
520 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
521 MODULE_DESCRIPTION("RTC driver for the WM831x series PMICs");
522 MODULE_LICENSE("GPL");
523 MODULE_ALIAS("platform:wm831x-rtc");