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[~shefty/rdma-dev.git] / drivers / rtc / rtc-wm831x.c
1 /*
2  *      Real Time Clock driver for Wolfson Microelectronics WM831x
3  *
4  *      Copyright (C) 2009 Wolfson Microelectronics PLC.
5  *
6  *  Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
7  *
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.
12  *
13  */
14
15 #include <linux/module.h>
16 #include <linux/kernel.h>
17 #include <linux/time.h>
18 #include <linux/rtc.h>
19 #include <linux/slab.h>
20 #include <linux/bcd.h>
21 #include <linux/interrupt.h>
22 #include <linux/ioctl.h>
23 #include <linux/completion.h>
24 #include <linux/mfd/wm831x/core.h>
25 #include <linux/delay.h>
26 #include <linux/platform_device.h>
27
28
29 /*
30  * R16416 (0x4020) - RTC Write Counter
31  */
32 #define WM831X_RTC_WR_CNT_MASK                  0xFFFF  /* RTC_WR_CNT - [15:0] */
33 #define WM831X_RTC_WR_CNT_SHIFT                      0  /* RTC_WR_CNT - [15:0] */
34 #define WM831X_RTC_WR_CNT_WIDTH                     16  /* RTC_WR_CNT - [15:0] */
35
36 /*
37  * R16417 (0x4021) - RTC Time 1
38  */
39 #define WM831X_RTC_TIME_MASK                    0xFFFF  /* RTC_TIME - [15:0] */
40 #define WM831X_RTC_TIME_SHIFT                        0  /* RTC_TIME - [15:0] */
41 #define WM831X_RTC_TIME_WIDTH                       16  /* RTC_TIME - [15:0] */
42
43 /*
44  * R16418 (0x4022) - RTC Time 2
45  */
46 #define WM831X_RTC_TIME_MASK                    0xFFFF  /* RTC_TIME - [15:0] */
47 #define WM831X_RTC_TIME_SHIFT                        0  /* RTC_TIME - [15:0] */
48 #define WM831X_RTC_TIME_WIDTH                       16  /* RTC_TIME - [15:0] */
49
50 /*
51  * R16419 (0x4023) - RTC Alarm 1
52  */
53 #define WM831X_RTC_ALM_MASK                     0xFFFF  /* RTC_ALM - [15:0] */
54 #define WM831X_RTC_ALM_SHIFT                         0  /* RTC_ALM - [15:0] */
55 #define WM831X_RTC_ALM_WIDTH                        16  /* RTC_ALM - [15:0] */
56
57 /*
58  * R16420 (0x4024) - RTC Alarm 2
59  */
60 #define WM831X_RTC_ALM_MASK                     0xFFFF  /* RTC_ALM - [15:0] */
61 #define WM831X_RTC_ALM_SHIFT                         0  /* RTC_ALM - [15:0] */
62 #define WM831X_RTC_ALM_WIDTH                        16  /* RTC_ALM - [15:0] */
63
64 /*
65  * R16421 (0x4025) - RTC Control
66  */
67 #define WM831X_RTC_VALID                        0x8000  /* RTC_VALID */
68 #define WM831X_RTC_VALID_MASK                   0x8000  /* RTC_VALID */
69 #define WM831X_RTC_VALID_SHIFT                      15  /* RTC_VALID */
70 #define WM831X_RTC_VALID_WIDTH                       1  /* RTC_VALID */
71 #define WM831X_RTC_SYNC_BUSY                    0x4000  /* RTC_SYNC_BUSY */
72 #define WM831X_RTC_SYNC_BUSY_MASK               0x4000  /* RTC_SYNC_BUSY */
73 #define WM831X_RTC_SYNC_BUSY_SHIFT                  14  /* RTC_SYNC_BUSY */
74 #define WM831X_RTC_SYNC_BUSY_WIDTH                   1  /* RTC_SYNC_BUSY */
75 #define WM831X_RTC_ALM_ENA                      0x0400  /* RTC_ALM_ENA */
76 #define WM831X_RTC_ALM_ENA_MASK                 0x0400  /* RTC_ALM_ENA */
77 #define WM831X_RTC_ALM_ENA_SHIFT                    10  /* RTC_ALM_ENA */
78 #define WM831X_RTC_ALM_ENA_WIDTH                     1  /* RTC_ALM_ENA */
79 #define WM831X_RTC_PINT_FREQ_MASK               0x0070  /* RTC_PINT_FREQ - [6:4] */
80 #define WM831X_RTC_PINT_FREQ_SHIFT                   4  /* RTC_PINT_FREQ - [6:4] */
81 #define WM831X_RTC_PINT_FREQ_WIDTH                   3  /* RTC_PINT_FREQ - [6:4] */
82
83 /*
84  * R16422 (0x4026) - RTC Trim
85  */
86 #define WM831X_RTC_TRIM_MASK                    0x03FF  /* RTC_TRIM - [9:0] */
87 #define WM831X_RTC_TRIM_SHIFT                        0  /* RTC_TRIM - [9:0] */
88 #define WM831X_RTC_TRIM_WIDTH                       10  /* RTC_TRIM - [9:0] */
89
90 #define WM831X_SET_TIME_RETRIES 5
91 #define WM831X_GET_TIME_RETRIES 5
92
93 struct wm831x_rtc {
94         struct wm831x *wm831x;
95         struct rtc_device *rtc;
96         unsigned int alarm_enabled:1;
97 };
98
99 /*
100  * Read current time and date in RTC
101  */
102 static int wm831x_rtc_readtime(struct device *dev, struct rtc_time *tm)
103 {
104         struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev);
105         struct wm831x *wm831x = wm831x_rtc->wm831x;
106         u16 time1[2], time2[2];
107         int ret;
108         int count = 0;
109
110         /* Has the RTC been programmed? */
111         ret = wm831x_reg_read(wm831x, WM831X_RTC_CONTROL);
112         if (ret < 0) {
113                 dev_err(dev, "Failed to read RTC control: %d\n", ret);
114                 return ret;
115         }
116         if (!(ret & WM831X_RTC_VALID)) {
117                 dev_dbg(dev, "RTC not yet configured\n");
118                 return -EINVAL;
119         }
120
121         /* Read twice to make sure we don't read a corrupt, partially
122          * incremented, value.
123          */
124         do {
125                 ret = wm831x_bulk_read(wm831x, WM831X_RTC_TIME_1,
126                                        2, time1);
127                 if (ret != 0)
128                         continue;
129
130                 ret = wm831x_bulk_read(wm831x, WM831X_RTC_TIME_1,
131                                        2, time2);
132                 if (ret != 0)
133                         continue;
134
135                 if (memcmp(time1, time2, sizeof(time1)) == 0) {
136                         u32 time = (time1[0] << 16) | time1[1];
137
138                         rtc_time_to_tm(time, tm);
139                         return rtc_valid_tm(tm);
140                 }
141
142         } while (++count < WM831X_GET_TIME_RETRIES);
143
144         dev_err(dev, "Timed out reading current time\n");
145
146         return -EIO;
147 }
148
149 /*
150  * Set current time and date in RTC
151  */
152 static int wm831x_rtc_set_mmss(struct device *dev, unsigned long time)
153 {
154         struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev);
155         struct wm831x *wm831x = wm831x_rtc->wm831x;
156         struct rtc_time new_tm;
157         unsigned long new_time;
158         int ret;
159         int count = 0;
160
161         ret = wm831x_reg_write(wm831x, WM831X_RTC_TIME_1,
162                                (time >> 16) & 0xffff);
163         if (ret < 0) {
164                 dev_err(dev, "Failed to write TIME_1: %d\n", ret);
165                 return ret;
166         }
167
168         ret = wm831x_reg_write(wm831x, WM831X_RTC_TIME_2, time & 0xffff);
169         if (ret < 0) {
170                 dev_err(dev, "Failed to write TIME_2: %d\n", ret);
171                 return ret;
172         }
173
174         /* Wait for the update to complete - should happen first time
175          * round but be conservative.
176          */
177         do {
178                 msleep(1);
179
180                 ret = wm831x_reg_read(wm831x, WM831X_RTC_CONTROL);
181                 if (ret < 0)
182                         ret = WM831X_RTC_SYNC_BUSY;
183         } while (!(ret & WM831X_RTC_SYNC_BUSY) &&
184                  ++count < WM831X_SET_TIME_RETRIES);
185
186         if (ret & WM831X_RTC_SYNC_BUSY) {
187                 dev_err(dev, "Timed out writing RTC update\n");
188                 return -EIO;
189         }
190
191         /* Check that the update was accepted; security features may
192          * have caused the update to be ignored.
193          */
194         ret = wm831x_rtc_readtime(dev, &new_tm);
195         if (ret < 0)
196                 return ret;
197
198         ret = rtc_tm_to_time(&new_tm, &new_time);
199         if (ret < 0) {
200                 dev_err(dev, "Failed to convert time: %d\n", ret);
201                 return ret;
202         }
203
204         /* Allow a second of change in case of tick */
205         if (new_time - time > 1) {
206                 dev_err(dev, "RTC update not permitted by hardware\n");
207                 return -EPERM;
208         }
209
210         return 0;
211 }
212
213 /*
214  * Read alarm time and date in RTC
215  */
216 static int wm831x_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
217 {
218         struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev);
219         int ret;
220         u16 data[2];
221         u32 time;
222
223         ret = wm831x_bulk_read(wm831x_rtc->wm831x, WM831X_RTC_ALARM_1,
224                                2, data);
225         if (ret != 0) {
226                 dev_err(dev, "Failed to read alarm time: %d\n", ret);
227                 return ret;
228         }
229
230         time = (data[0] << 16) | data[1];
231
232         rtc_time_to_tm(time, &alrm->time);
233
234         ret = wm831x_reg_read(wm831x_rtc->wm831x, WM831X_RTC_CONTROL);
235         if (ret < 0) {
236                 dev_err(dev, "Failed to read RTC control: %d\n", ret);
237                 return ret;
238         }
239
240         if (ret & WM831X_RTC_ALM_ENA)
241                 alrm->enabled = 1;
242         else
243                 alrm->enabled = 0;
244
245         return 0;
246 }
247
248 static int wm831x_rtc_stop_alarm(struct wm831x_rtc *wm831x_rtc)
249 {
250         wm831x_rtc->alarm_enabled = 0;
251
252         return wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL,
253                                WM831X_RTC_ALM_ENA, 0);
254 }
255
256 static int wm831x_rtc_start_alarm(struct wm831x_rtc *wm831x_rtc)
257 {
258         wm831x_rtc->alarm_enabled = 1;
259
260         return wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL,
261                                WM831X_RTC_ALM_ENA, WM831X_RTC_ALM_ENA);
262 }
263
264 static int wm831x_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
265 {
266         struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev);
267         struct wm831x *wm831x = wm831x_rtc->wm831x;
268         int ret;
269         unsigned long time;
270
271         ret = rtc_tm_to_time(&alrm->time, &time);
272         if (ret < 0) {
273                 dev_err(dev, "Failed to convert time: %d\n", ret);
274                 return ret;
275         }
276
277         ret = wm831x_rtc_stop_alarm(wm831x_rtc);
278         if (ret < 0) {
279                 dev_err(dev, "Failed to stop alarm: %d\n", ret);
280                 return ret;
281         }
282
283         ret = wm831x_reg_write(wm831x, WM831X_RTC_ALARM_1,
284                                (time >> 16) & 0xffff);
285         if (ret < 0) {
286                 dev_err(dev, "Failed to write ALARM_1: %d\n", ret);
287                 return ret;
288         }
289
290         ret = wm831x_reg_write(wm831x, WM831X_RTC_ALARM_2, time & 0xffff);
291         if (ret < 0) {
292                 dev_err(dev, "Failed to write ALARM_2: %d\n", ret);
293                 return ret;
294         }
295
296         if (alrm->enabled) {
297                 ret = wm831x_rtc_start_alarm(wm831x_rtc);
298                 if (ret < 0) {
299                         dev_err(dev, "Failed to start alarm: %d\n", ret);
300                         return ret;
301                 }
302         }
303
304         return 0;
305 }
306
307 static int wm831x_rtc_alarm_irq_enable(struct device *dev,
308                                        unsigned int enabled)
309 {
310         struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev);
311
312         if (enabled)
313                 return wm831x_rtc_start_alarm(wm831x_rtc);
314         else
315                 return wm831x_rtc_stop_alarm(wm831x_rtc);
316 }
317
318 static irqreturn_t wm831x_alm_irq(int irq, void *data)
319 {
320         struct wm831x_rtc *wm831x_rtc = data;
321
322         rtc_update_irq(wm831x_rtc->rtc, 1, RTC_IRQF | RTC_AF);
323
324         return IRQ_HANDLED;
325 }
326
327 static irqreturn_t wm831x_per_irq(int irq, void *data)
328 {
329         struct wm831x_rtc *wm831x_rtc = data;
330
331         rtc_update_irq(wm831x_rtc->rtc, 1, RTC_IRQF | RTC_UF);
332
333         return IRQ_HANDLED;
334 }
335
336 static const struct rtc_class_ops wm831x_rtc_ops = {
337         .read_time = wm831x_rtc_readtime,
338         .set_mmss = wm831x_rtc_set_mmss,
339         .read_alarm = wm831x_rtc_readalarm,
340         .set_alarm = wm831x_rtc_setalarm,
341         .alarm_irq_enable = wm831x_rtc_alarm_irq_enable,
342 };
343
344 #ifdef CONFIG_PM
345 /* Turn off the alarm if it should not be a wake source. */
346 static int wm831x_rtc_suspend(struct device *dev)
347 {
348         struct platform_device *pdev = to_platform_device(dev);
349         struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(&pdev->dev);
350         int ret, enable;
351
352         if (wm831x_rtc->alarm_enabled && device_may_wakeup(&pdev->dev))
353                 enable = WM831X_RTC_ALM_ENA;
354         else
355                 enable = 0;
356
357         ret = wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL,
358                               WM831X_RTC_ALM_ENA, enable);
359         if (ret != 0)
360                 dev_err(&pdev->dev, "Failed to update RTC alarm: %d\n", ret);
361
362         return 0;
363 }
364
365 /* Enable the alarm if it should be enabled (in case it was disabled to
366  * prevent use as a wake source).
367  */
368 static int wm831x_rtc_resume(struct device *dev)
369 {
370         struct platform_device *pdev = to_platform_device(dev);
371         struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(&pdev->dev);
372         int ret;
373
374         if (wm831x_rtc->alarm_enabled) {
375                 ret = wm831x_rtc_start_alarm(wm831x_rtc);
376                 if (ret != 0)
377                         dev_err(&pdev->dev,
378                                 "Failed to restart RTC alarm: %d\n", ret);
379         }
380
381         return 0;
382 }
383
384 /* Unconditionally disable the alarm */
385 static int wm831x_rtc_freeze(struct device *dev)
386 {
387         struct platform_device *pdev = to_platform_device(dev);
388         struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(&pdev->dev);
389         int ret;
390
391         ret = wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL,
392                               WM831X_RTC_ALM_ENA, 0);
393         if (ret != 0)
394                 dev_err(&pdev->dev, "Failed to stop RTC alarm: %d\n", ret);
395
396         return 0;
397 }
398 #else
399 #define wm831x_rtc_suspend NULL
400 #define wm831x_rtc_resume NULL
401 #define wm831x_rtc_freeze NULL
402 #endif
403
404 static int wm831x_rtc_probe(struct platform_device *pdev)
405 {
406         struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
407         struct wm831x_rtc *wm831x_rtc;
408         int per_irq = platform_get_irq_byname(pdev, "PER");
409         int alm_irq = platform_get_irq_byname(pdev, "ALM");
410         int ret = 0;
411
412         wm831x_rtc = kzalloc(sizeof(*wm831x_rtc), GFP_KERNEL);
413         if (wm831x_rtc == NULL)
414                 return -ENOMEM;
415
416         platform_set_drvdata(pdev, wm831x_rtc);
417         wm831x_rtc->wm831x = wm831x;
418
419         ret = wm831x_reg_read(wm831x, WM831X_RTC_CONTROL);
420         if (ret < 0) {
421                 dev_err(&pdev->dev, "Failed to read RTC control: %d\n", ret);
422                 goto err;
423         }
424         if (ret & WM831X_RTC_ALM_ENA)
425                 wm831x_rtc->alarm_enabled = 1;
426
427         device_init_wakeup(&pdev->dev, 1);
428
429         wm831x_rtc->rtc = rtc_device_register("wm831x", &pdev->dev,
430                                               &wm831x_rtc_ops, THIS_MODULE);
431         if (IS_ERR(wm831x_rtc->rtc)) {
432                 ret = PTR_ERR(wm831x_rtc->rtc);
433                 goto err;
434         }
435
436         ret = request_threaded_irq(per_irq, NULL, wm831x_per_irq,
437                                    IRQF_TRIGGER_RISING, "RTC period",
438                                    wm831x_rtc);
439         if (ret != 0) {
440                 dev_err(&pdev->dev, "Failed to request periodic IRQ %d: %d\n",
441                         per_irq, ret);
442         }
443
444         ret = request_threaded_irq(alm_irq, NULL, wm831x_alm_irq,
445                                    IRQF_TRIGGER_RISING, "RTC alarm",
446                                    wm831x_rtc);
447         if (ret != 0) {
448                 dev_err(&pdev->dev, "Failed to request alarm IRQ %d: %d\n",
449                         alm_irq, ret);
450         }
451
452         return 0;
453
454 err:
455         kfree(wm831x_rtc);
456         return ret;
457 }
458
459 static int __devexit wm831x_rtc_remove(struct platform_device *pdev)
460 {
461         struct wm831x_rtc *wm831x_rtc = platform_get_drvdata(pdev);
462         int per_irq = platform_get_irq_byname(pdev, "PER");
463         int alm_irq = platform_get_irq_byname(pdev, "ALM");
464
465         free_irq(alm_irq, wm831x_rtc);
466         free_irq(per_irq, wm831x_rtc);
467         rtc_device_unregister(wm831x_rtc->rtc);
468         kfree(wm831x_rtc);
469
470         return 0;
471 }
472
473 static const struct dev_pm_ops wm831x_rtc_pm_ops = {
474         .suspend = wm831x_rtc_suspend,
475         .resume = wm831x_rtc_resume,
476
477         .freeze = wm831x_rtc_freeze,
478         .thaw = wm831x_rtc_resume,
479         .restore = wm831x_rtc_resume,
480
481         .poweroff = wm831x_rtc_suspend,
482 };
483
484 static struct platform_driver wm831x_rtc_driver = {
485         .probe = wm831x_rtc_probe,
486         .remove = __devexit_p(wm831x_rtc_remove),
487         .driver = {
488                 .name = "wm831x-rtc",
489                 .pm = &wm831x_rtc_pm_ops,
490         },
491 };
492
493 static int __init wm831x_rtc_init(void)
494 {
495         return platform_driver_register(&wm831x_rtc_driver);
496 }
497 module_init(wm831x_rtc_init);
498
499 static void __exit wm831x_rtc_exit(void)
500 {
501         platform_driver_unregister(&wm831x_rtc_driver);
502 }
503 module_exit(wm831x_rtc_exit);
504
505 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
506 MODULE_DESCRIPTION("RTC driver for the WM831x series PMICs");
507 MODULE_LICENSE("GPL");
508 MODULE_ALIAS("platform:wm831x-rtc");