1 /*
2 * RTC driver for Maxim MAX77802
3 *
4 * Copyright (C) 2013 Google, Inc
5 *
6 * Copyright (C) 2012 Samsung Electronics Co.Ltd
7 *
8 * based on rtc-max8997.c
9 *
10 * This program is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License as published by the
12 * Free Software Foundation; either version 2 of the License, or (at your
13 * option) any later version.
14 *
15 */
16
17 #include <linux/slab.h>
18 #include <linux/rtc.h>
19 #include <linux/delay.h>
20 #include <linux/mutex.h>
21 #include <linux/module.h>
22 #include <linux/platform_device.h>
23 #include <linux/mfd/max77686-private.h>
24 #include <linux/irqdomain.h>
25 #include <linux/regmap.h>
26
27 /* RTC Control Register */
28 #define BCD_EN_SHIFT 0
29 #define BCD_EN_MASK (1 << BCD_EN_SHIFT)
30 #define MODEL24_SHIFT 1
31 #define MODEL24_MASK (1 << MODEL24_SHIFT)
32 /* RTC Update Register1 */
33 #define RTC_UDR_SHIFT 0
34 #define RTC_UDR_MASK (1 << RTC_UDR_SHIFT)
35 #define RTC_RBUDR_SHIFT 4
36 #define RTC_RBUDR_MASK (1 << RTC_RBUDR_SHIFT)
37 /* RTC Hour register */
38 #define HOUR_PM_SHIFT 6
39 #define HOUR_PM_MASK (1 << HOUR_PM_SHIFT)
40 /* RTC Alarm Enable */
41 #define ALARM_ENABLE_SHIFT 7
42 #define ALARM_ENABLE_MASK (1 << ALARM_ENABLE_SHIFT)
43
44 /* For the RTCAE1 register, we write this value to enable the alarm */
45 #define ALARM_ENABLE_VALUE 0x77
46
47 #define MAX77802_RTC_UPDATE_DELAY_US 200
48
49 enum {
50 RTC_SEC = 0,
51 RTC_MIN,
52 RTC_HOUR,
53 RTC_WEEKDAY,
54 RTC_MONTH,
55 RTC_YEAR,
56 RTC_DATE,
57 RTC_NR_TIME
58 };
59
60 struct max77802_rtc_info {
61 struct device *dev;
62 struct max77686_dev *max77802;
63 struct i2c_client *rtc;
64 struct rtc_device *rtc_dev;
65 struct mutex lock;
66
67 struct regmap *regmap;
68
69 int virq;
70 int rtc_24hr_mode;
71 };
72
73 enum MAX77802_RTC_OP {
74 MAX77802_RTC_WRITE,
75 MAX77802_RTC_READ,
76 };
77
max77802_rtc_data_to_tm(u8 * data,struct rtc_time * tm,int rtc_24hr_mode)78 static void max77802_rtc_data_to_tm(u8 *data, struct rtc_time *tm,
79 int rtc_24hr_mode)
80 {
81 tm->tm_sec = data[RTC_SEC] & 0xff;
82 tm->tm_min = data[RTC_MIN] & 0xff;
83 if (rtc_24hr_mode)
84 tm->tm_hour = data[RTC_HOUR] & 0x1f;
85 else {
86 tm->tm_hour = data[RTC_HOUR] & 0x0f;
87 if (data[RTC_HOUR] & HOUR_PM_MASK)
88 tm->tm_hour += 12;
89 }
90
91 /* Only a single bit is set in data[], so fls() would be equivalent */
92 tm->tm_wday = ffs(data[RTC_WEEKDAY] & 0xff) - 1;
93 tm->tm_mday = data[RTC_DATE] & 0x1f;
94 tm->tm_mon = (data[RTC_MONTH] & 0x0f) - 1;
95
96 tm->tm_year = data[RTC_YEAR] & 0xff;
97 tm->tm_yday = 0;
98 tm->tm_isdst = 0;
99 }
100
max77802_rtc_tm_to_data(struct rtc_time * tm,u8 * data)101 static int max77802_rtc_tm_to_data(struct rtc_time *tm, u8 *data)
102 {
103 data[RTC_SEC] = tm->tm_sec;
104 data[RTC_MIN] = tm->tm_min;
105 data[RTC_HOUR] = tm->tm_hour;
106 data[RTC_WEEKDAY] = 1 << tm->tm_wday;
107 data[RTC_DATE] = tm->tm_mday;
108 data[RTC_MONTH] = tm->tm_mon + 1;
109 data[RTC_YEAR] = tm->tm_year;
110
111 return 0;
112 }
113
max77802_rtc_update(struct max77802_rtc_info * info,enum MAX77802_RTC_OP op)114 static int max77802_rtc_update(struct max77802_rtc_info *info,
115 enum MAX77802_RTC_OP op)
116 {
117 int ret;
118 unsigned int data;
119
120 if (op == MAX77802_RTC_WRITE)
121 data = 1 << RTC_UDR_SHIFT;
122 else
123 data = 1 << RTC_RBUDR_SHIFT;
124
125 ret = regmap_update_bits(info->max77802->regmap,
126 MAX77802_RTC_UPDATE0, data, data);
127 if (ret < 0)
128 dev_err(info->dev, "%s: fail to write update reg(ret=%d, data=0x%x)\n",
129 __func__, ret, data);
130 else {
131 /* Minimum delay required before RTC update. */
132 usleep_range(MAX77802_RTC_UPDATE_DELAY_US,
133 MAX77802_RTC_UPDATE_DELAY_US * 2);
134 }
135
136 return ret;
137 }
138
max77802_rtc_read_time(struct device * dev,struct rtc_time * tm)139 static int max77802_rtc_read_time(struct device *dev, struct rtc_time *tm)
140 {
141 struct max77802_rtc_info *info = dev_get_drvdata(dev);
142 u8 data[RTC_NR_TIME];
143 int ret;
144
145 mutex_lock(&info->lock);
146
147 ret = max77802_rtc_update(info, MAX77802_RTC_READ);
148 if (ret < 0)
149 goto out;
150
151 ret = regmap_bulk_read(info->max77802->regmap,
152 MAX77802_RTC_SEC, data, RTC_NR_TIME);
153 if (ret < 0) {
154 dev_err(info->dev, "%s: fail to read time reg(%d)\n", __func__,
155 ret);
156 goto out;
157 }
158
159 max77802_rtc_data_to_tm(data, tm, info->rtc_24hr_mode);
160
161 ret = rtc_valid_tm(tm);
162
163 out:
164 mutex_unlock(&info->lock);
165 return ret;
166 }
167
max77802_rtc_set_time(struct device * dev,struct rtc_time * tm)168 static int max77802_rtc_set_time(struct device *dev, struct rtc_time *tm)
169 {
170 struct max77802_rtc_info *info = dev_get_drvdata(dev);
171 u8 data[RTC_NR_TIME];
172 int ret;
173
174 ret = max77802_rtc_tm_to_data(tm, data);
175 if (ret < 0)
176 return ret;
177
178 mutex_lock(&info->lock);
179
180 ret = regmap_bulk_write(info->max77802->regmap,
181 MAX77802_RTC_SEC, data, RTC_NR_TIME);
182 if (ret < 0) {
183 dev_err(info->dev, "%s: fail to write time reg(%d)\n", __func__,
184 ret);
185 goto out;
186 }
187
188 ret = max77802_rtc_update(info, MAX77802_RTC_WRITE);
189
190 out:
191 mutex_unlock(&info->lock);
192 return ret;
193 }
194
max77802_rtc_read_alarm(struct device * dev,struct rtc_wkalrm * alrm)195 static int max77802_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
196 {
197 struct max77802_rtc_info *info = dev_get_drvdata(dev);
198 u8 data[RTC_NR_TIME];
199 unsigned int val;
200 int ret;
201
202 mutex_lock(&info->lock);
203
204 ret = max77802_rtc_update(info, MAX77802_RTC_READ);
205 if (ret < 0)
206 goto out;
207
208 ret = regmap_bulk_read(info->max77802->regmap,
209 MAX77802_ALARM1_SEC, data, RTC_NR_TIME);
210 if (ret < 0) {
211 dev_err(info->dev, "%s:%d fail to read alarm reg(%d)\n",
212 __func__, __LINE__, ret);
213 goto out;
214 }
215
216 max77802_rtc_data_to_tm(data, &alrm->time, info->rtc_24hr_mode);
217
218 alrm->enabled = 0;
219 ret = regmap_read(info->max77802->regmap,
220 MAX77802_RTC_AE1, &val);
221 if (ret < 0) {
222 dev_err(info->dev, "%s:%d fail to read alarm enable(%d)\n",
223 __func__, __LINE__, ret);
224 goto out;
225 }
226 if (val)
227 alrm->enabled = 1;
228
229 alrm->pending = 0;
230 ret = regmap_read(info->max77802->regmap, MAX77802_REG_STATUS2, &val);
231 if (ret < 0) {
232 dev_err(info->dev, "%s:%d fail to read status2 reg(%d)\n",
233 __func__, __LINE__, ret);
234 goto out;
235 }
236
237 if (val & (1 << 2)) /* RTCA1 */
238 alrm->pending = 1;
239
240 out:
241 mutex_unlock(&info->lock);
242 return 0;
243 }
244
max77802_rtc_stop_alarm(struct max77802_rtc_info * info)245 static int max77802_rtc_stop_alarm(struct max77802_rtc_info *info)
246 {
247 int ret;
248
249 if (!mutex_is_locked(&info->lock))
250 dev_warn(info->dev, "%s: should have mutex locked\n", __func__);
251
252 ret = max77802_rtc_update(info, MAX77802_RTC_READ);
253 if (ret < 0)
254 goto out;
255
256 ret = regmap_write(info->max77802->regmap,
257 MAX77802_RTC_AE1, 0);
258 if (ret < 0) {
259 dev_err(info->dev, "%s: fail to write alarm reg(%d)\n",
260 __func__, ret);
261 goto out;
262 }
263
264 ret = max77802_rtc_update(info, MAX77802_RTC_WRITE);
265 out:
266 return ret;
267 }
268
max77802_rtc_start_alarm(struct max77802_rtc_info * info)269 static int max77802_rtc_start_alarm(struct max77802_rtc_info *info)
270 {
271 int ret;
272
273 if (!mutex_is_locked(&info->lock))
274 dev_warn(info->dev, "%s: should have mutex locked\n",
275 __func__);
276
277 ret = max77802_rtc_update(info, MAX77802_RTC_READ);
278 if (ret < 0)
279 goto out;
280
281 ret = regmap_write(info->max77802->regmap,
282 MAX77802_RTC_AE1,
283 ALARM_ENABLE_VALUE);
284
285 if (ret < 0) {
286 dev_err(info->dev, "%s: fail to read alarm reg(%d)\n",
287 __func__, ret);
288 goto out;
289 }
290
291 ret = max77802_rtc_update(info, MAX77802_RTC_WRITE);
292 out:
293 return ret;
294 }
295
max77802_rtc_set_alarm(struct device * dev,struct rtc_wkalrm * alrm)296 static int max77802_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
297 {
298 struct max77802_rtc_info *info = dev_get_drvdata(dev);
299 u8 data[RTC_NR_TIME];
300 int ret;
301
302 ret = max77802_rtc_tm_to_data(&alrm->time, data);
303 if (ret < 0)
304 return ret;
305
306 mutex_lock(&info->lock);
307
308 ret = max77802_rtc_stop_alarm(info);
309 if (ret < 0)
310 goto out;
311
312 ret = regmap_bulk_write(info->max77802->regmap,
313 MAX77802_ALARM1_SEC, data, RTC_NR_TIME);
314
315 if (ret < 0) {
316 dev_err(info->dev, "%s: fail to write alarm reg(%d)\n",
317 __func__, ret);
318 goto out;
319 }
320
321 ret = max77802_rtc_update(info, MAX77802_RTC_WRITE);
322 if (ret < 0)
323 goto out;
324
325 if (alrm->enabled)
326 ret = max77802_rtc_start_alarm(info);
327 out:
328 mutex_unlock(&info->lock);
329 return ret;
330 }
331
max77802_rtc_alarm_irq_enable(struct device * dev,unsigned int enabled)332 static int max77802_rtc_alarm_irq_enable(struct device *dev,
333 unsigned int enabled)
334 {
335 struct max77802_rtc_info *info = dev_get_drvdata(dev);
336 int ret;
337
338 mutex_lock(&info->lock);
339 if (enabled)
340 ret = max77802_rtc_start_alarm(info);
341 else
342 ret = max77802_rtc_stop_alarm(info);
343 mutex_unlock(&info->lock);
344
345 return ret;
346 }
347
max77802_rtc_alarm_irq(int irq,void * data)348 static irqreturn_t max77802_rtc_alarm_irq(int irq, void *data)
349 {
350 struct max77802_rtc_info *info = data;
351
352 dev_dbg(info->dev, "%s:irq(%d)\n", __func__, irq);
353
354 rtc_update_irq(info->rtc_dev, 1, RTC_IRQF | RTC_AF);
355
356 return IRQ_HANDLED;
357 }
358
359 static const struct rtc_class_ops max77802_rtc_ops = {
360 .read_time = max77802_rtc_read_time,
361 .set_time = max77802_rtc_set_time,
362 .read_alarm = max77802_rtc_read_alarm,
363 .set_alarm = max77802_rtc_set_alarm,
364 .alarm_irq_enable = max77802_rtc_alarm_irq_enable,
365 };
366
max77802_rtc_init_reg(struct max77802_rtc_info * info)367 static int max77802_rtc_init_reg(struct max77802_rtc_info *info)
368 {
369 u8 data[2];
370 int ret;
371
372 max77802_rtc_update(info, MAX77802_RTC_READ);
373
374 /* Set RTC control register : Binary mode, 24hour mdoe */
375 data[0] = (1 << BCD_EN_SHIFT) | (1 << MODEL24_SHIFT);
376 data[1] = (0 << BCD_EN_SHIFT) | (1 << MODEL24_SHIFT);
377
378 info->rtc_24hr_mode = 1;
379
380 ret = regmap_bulk_write(info->max77802->regmap,
381 MAX77802_RTC_CONTROLM, data, ARRAY_SIZE(data));
382 if (ret < 0) {
383 dev_err(info->dev, "%s: fail to write controlm reg(%d)\n",
384 __func__, ret);
385 return ret;
386 }
387
388 ret = max77802_rtc_update(info, MAX77802_RTC_WRITE);
389 return ret;
390 }
391
max77802_rtc_probe(struct platform_device * pdev)392 static int max77802_rtc_probe(struct platform_device *pdev)
393 {
394 struct max77686_dev *max77802 = dev_get_drvdata(pdev->dev.parent);
395 struct max77802_rtc_info *info;
396 int ret;
397
398 dev_dbg(&pdev->dev, "%s\n", __func__);
399
400 info = devm_kzalloc(&pdev->dev, sizeof(struct max77802_rtc_info),
401 GFP_KERNEL);
402 if (!info)
403 return -ENOMEM;
404
405 mutex_init(&info->lock);
406 info->dev = &pdev->dev;
407 info->max77802 = max77802;
408 info->rtc = max77802->i2c;
409
410 platform_set_drvdata(pdev, info);
411
412 ret = max77802_rtc_init_reg(info);
413
414 if (ret < 0) {
415 dev_err(&pdev->dev, "Failed to initialize RTC reg:%d\n", ret);
416 return ret;
417 }
418
419 device_init_wakeup(&pdev->dev, 1);
420
421 info->rtc_dev = devm_rtc_device_register(&pdev->dev, "max77802-rtc",
422 &max77802_rtc_ops, THIS_MODULE);
423
424 if (IS_ERR(info->rtc_dev)) {
425 ret = PTR_ERR(info->rtc_dev);
426 dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
427 if (ret == 0)
428 ret = -EINVAL;
429 return ret;
430 }
431
432 if (!max77802->rtc_irq_data) {
433 dev_err(&pdev->dev, "No RTC regmap IRQ chip\n");
434 return -EINVAL;
435 }
436
437 info->virq = regmap_irq_get_virq(max77802->rtc_irq_data,
438 MAX77686_RTCIRQ_RTCA1);
439
440 if (info->virq <= 0) {
441 dev_err(&pdev->dev, "Failed to get virtual IRQ %d\n",
442 MAX77686_RTCIRQ_RTCA1);
443 return -EINVAL;
444 }
445
446 ret = devm_request_threaded_irq(&pdev->dev, info->virq, NULL,
447 max77802_rtc_alarm_irq, 0, "rtc-alarm1",
448 info);
449 if (ret < 0)
450 dev_err(&pdev->dev, "Failed to request alarm IRQ: %d: %d\n",
451 info->virq, ret);
452
453 return ret;
454 }
455
456 #ifdef CONFIG_PM_SLEEP
max77802_rtc_suspend(struct device * dev)457 static int max77802_rtc_suspend(struct device *dev)
458 {
459 if (device_may_wakeup(dev)) {
460 struct max77802_rtc_info *info = dev_get_drvdata(dev);
461
462 return enable_irq_wake(info->virq);
463 }
464
465 return 0;
466 }
467
max77802_rtc_resume(struct device * dev)468 static int max77802_rtc_resume(struct device *dev)
469 {
470 if (device_may_wakeup(dev)) {
471 struct max77802_rtc_info *info = dev_get_drvdata(dev);
472
473 return disable_irq_wake(info->virq);
474 }
475
476 return 0;
477 }
478 #endif
479
480 static SIMPLE_DEV_PM_OPS(max77802_rtc_pm_ops,
481 max77802_rtc_suspend, max77802_rtc_resume);
482
483 static const struct platform_device_id rtc_id[] = {
484 { "max77802-rtc", 0 },
485 {},
486 };
487
488 static struct platform_driver max77802_rtc_driver = {
489 .driver = {
490 .name = "max77802-rtc",
491 .owner = THIS_MODULE,
492 .pm = &max77802_rtc_pm_ops,
493 },
494 .probe = max77802_rtc_probe,
495 .id_table = rtc_id,
496 };
497
498 module_platform_driver(max77802_rtc_driver);
499
500 MODULE_DESCRIPTION("Maxim MAX77802 RTC driver");
501 MODULE_AUTHOR("Simon Glass <sjg@chromium.org>");
502 MODULE_LICENSE("GPL");
503