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Linux 4.1.16
[linux/fpc-iii.git] / drivers / rtc / rtc-ab8500.c
blob6856f0a3a3d55cbb360e4671d70148b6bccc688c
1 /*
2 * Copyright (C) ST-Ericsson SA 2010
3 *
4 * License terms: GNU General Public License (GPL) version 2
5 * Author: Virupax Sadashivpetimath <virupax.sadashivpetimath@stericsson.com>
6 *
7 * RTC clock driver for the RTC part of the AB8500 Power management chip.
8 * Based on RTC clock driver for the AB3100 Analog Baseband Chip by
9 * Linus Walleij <linus.walleij@stericsson.com>
10 */
11
12 #include <linux/module.h>
13 #include <linux/kernel.h>
14 #include <linux/init.h>
15 #include <linux/platform_device.h>
16 #include <linux/rtc.h>
17 #include <linux/mfd/abx500.h>
18 #include <linux/mfd/abx500/ab8500.h>
19 #include <linux/delay.h>
20 #include <linux/of.h>
21
22 #define AB8500_RTC_SOFF_STAT_REG 0x00
23 #define AB8500_RTC_CC_CONF_REG 0x01
24 #define AB8500_RTC_READ_REQ_REG 0x02
25 #define AB8500_RTC_WATCH_TSECMID_REG 0x03
26 #define AB8500_RTC_WATCH_TSECHI_REG 0x04
27 #define AB8500_RTC_WATCH_TMIN_LOW_REG 0x05
28 #define AB8500_RTC_WATCH_TMIN_MID_REG 0x06
29 #define AB8500_RTC_WATCH_TMIN_HI_REG 0x07
30 #define AB8500_RTC_ALRM_MIN_LOW_REG 0x08
31 #define AB8500_RTC_ALRM_MIN_MID_REG 0x09
32 #define AB8500_RTC_ALRM_MIN_HI_REG 0x0A
33 #define AB8500_RTC_STAT_REG 0x0B
34 #define AB8500_RTC_BKUP_CHG_REG 0x0C
35 #define AB8500_RTC_FORCE_BKUP_REG 0x0D
36 #define AB8500_RTC_CALIB_REG 0x0E
37 #define AB8500_RTC_SWITCH_STAT_REG 0x0F
38 #define AB8540_RTC_ALRM_SEC 0x22
39 #define AB8540_RTC_ALRM_MIN_LOW_REG 0x23
40 #define AB8540_RTC_ALRM_MIN_MID_REG 0x24
41 #define AB8540_RTC_ALRM_MIN_HI_REG 0x25
42
43 /* RtcReadRequest bits */
44 #define RTC_READ_REQUEST 0x01
45 #define RTC_WRITE_REQUEST 0x02
46
47 /* RtcCtrl bits */
48 #define RTC_ALARM_ENA 0x04
49 #define RTC_STATUS_DATA 0x01
50
51 #define COUNTS_PER_SEC (0xF000 / 60)
52 #define AB8500_RTC_EPOCH 2000
53
54 static const u8 ab8500_rtc_time_regs[] = {
55 AB8500_RTC_WATCH_TMIN_HI_REG, AB8500_RTC_WATCH_TMIN_MID_REG,
56 AB8500_RTC_WATCH_TMIN_LOW_REG, AB8500_RTC_WATCH_TSECHI_REG,
57 AB8500_RTC_WATCH_TSECMID_REG
58 };
59
60 static const u8 ab8500_rtc_alarm_regs[] = {
61 AB8500_RTC_ALRM_MIN_HI_REG, AB8500_RTC_ALRM_MIN_MID_REG,
62 AB8500_RTC_ALRM_MIN_LOW_REG
63 };
64
65 static const u8 ab8540_rtc_alarm_regs[] = {
66 AB8540_RTC_ALRM_MIN_HI_REG, AB8540_RTC_ALRM_MIN_MID_REG,
67 AB8540_RTC_ALRM_MIN_LOW_REG, AB8540_RTC_ALRM_SEC
68 };
69
70 /* Calculate the seconds from 1970 to 01-01-2000 00:00:00 */
71 static unsigned long get_elapsed_seconds(int year)
72 {
73 unsigned long secs;
74 struct rtc_time tm = {
75 .tm_year = year - 1900,
76 .tm_mday = 1,
77 };
78
79 /*
80 * This function calculates secs from 1970 and not from
81 * 1900, even if we supply the offset from year 1900.
82 */
83 rtc_tm_to_time(&tm, &secs);
84 return secs;
85 }
86
87 static int ab8500_rtc_read_time(struct device *dev, struct rtc_time *tm)
88 {
89 unsigned long timeout = jiffies + HZ;
90 int retval, i;
91 unsigned long mins, secs;
92 unsigned char buf[ARRAY_SIZE(ab8500_rtc_time_regs)];
93 u8 value;
94
95 /* Request a data read */
96 retval = abx500_set_register_interruptible(dev,
97 AB8500_RTC, AB8500_RTC_READ_REQ_REG, RTC_READ_REQUEST);
98 if (retval < 0)
99 return retval;
100
101 /* Wait for some cycles after enabling the rtc read in ab8500 */
102 while (time_before(jiffies, timeout)) {
103 retval = abx500_get_register_interruptible(dev,
104 AB8500_RTC, AB8500_RTC_READ_REQ_REG, &value);
105 if (retval < 0)
106 return retval;
107
108 if (!(value & RTC_READ_REQUEST))
109 break;
110
111 usleep_range(1000, 5000);
112 }
113
114 /* Read the Watchtime registers */
115 for (i = 0; i < ARRAY_SIZE(ab8500_rtc_time_regs); i++) {
116 retval = abx500_get_register_interruptible(dev,
117 AB8500_RTC, ab8500_rtc_time_regs[i], &value);
118 if (retval < 0)
119 return retval;
120 buf[i] = value;
121 }
122
123 mins = (buf[0] << 16) | (buf[1] << 8) | buf[2];
124
125 secs = (buf[3] << 8) | buf[4];
126 secs = secs / COUNTS_PER_SEC;
127 secs = secs + (mins * 60);
128
129 /* Add back the initially subtracted number of seconds */
130 secs += get_elapsed_seconds(AB8500_RTC_EPOCH);
131
132 rtc_time_to_tm(secs, tm);
133 return rtc_valid_tm(tm);
134 }
135
136 static int ab8500_rtc_set_time(struct device *dev, struct rtc_time *tm)
137 {
138 int retval, i;
139 unsigned char buf[ARRAY_SIZE(ab8500_rtc_time_regs)];
140 unsigned long no_secs, no_mins, secs = 0;
141
142 if (tm->tm_year < (AB8500_RTC_EPOCH - 1900)) {
143 dev_dbg(dev, "year should be equal to or greater than %d\n",
144 AB8500_RTC_EPOCH);
145 return -EINVAL;
146 }
147
148 /* Get the number of seconds since 1970 */
149 rtc_tm_to_time(tm, &secs);
150
151 /*
152 * Convert it to the number of seconds since 01-01-2000 00:00:00, since
153 * we only have a small counter in the RTC.
154 */
155 secs -= get_elapsed_seconds(AB8500_RTC_EPOCH);
156
157 no_mins = secs / 60;
158
159 no_secs = secs % 60;
160 /* Make the seconds count as per the RTC resolution */
161 no_secs = no_secs * COUNTS_PER_SEC;
162
163 buf[4] = no_secs & 0xFF;
164 buf[3] = (no_secs >> 8) & 0xFF;
165
166 buf[2] = no_mins & 0xFF;
167 buf[1] = (no_mins >> 8) & 0xFF;
168 buf[0] = (no_mins >> 16) & 0xFF;
169
170 for (i = 0; i < ARRAY_SIZE(ab8500_rtc_time_regs); i++) {
171 retval = abx500_set_register_interruptible(dev, AB8500_RTC,
172 ab8500_rtc_time_regs[i], buf[i]);
173 if (retval < 0)
174 return retval;
175 }
176
177 /* Request a data write */
178 return abx500_set_register_interruptible(dev, AB8500_RTC,
179 AB8500_RTC_READ_REQ_REG, RTC_WRITE_REQUEST);
180 }
181
182 static int ab8500_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
183 {
184 int retval, i;
185 u8 rtc_ctrl, value;
186 unsigned char buf[ARRAY_SIZE(ab8500_rtc_alarm_regs)];
187 unsigned long secs, mins;
188
189 /* Check if the alarm is enabled or not */
190 retval = abx500_get_register_interruptible(dev, AB8500_RTC,
191 AB8500_RTC_STAT_REG, &rtc_ctrl);
192 if (retval < 0)
193 return retval;
194
195 if (rtc_ctrl & RTC_ALARM_ENA)
196 alarm->enabled = 1;
197 else
198 alarm->enabled = 0;
199
200 alarm->pending = 0;
201
202 for (i = 0; i < ARRAY_SIZE(ab8500_rtc_alarm_regs); i++) {
203 retval = abx500_get_register_interruptible(dev, AB8500_RTC,
204 ab8500_rtc_alarm_regs[i], &value);
205 if (retval < 0)
206 return retval;
207 buf[i] = value;
208 }
209
210 mins = (buf[0] << 16) | (buf[1] << 8) | (buf[2]);
211 secs = mins * 60;
212
213 /* Add back the initially subtracted number of seconds */
214 secs += get_elapsed_seconds(AB8500_RTC_EPOCH);
215
216 rtc_time_to_tm(secs, &alarm->time);
217
218 return rtc_valid_tm(&alarm->time);
219 }
220
221 static int ab8500_rtc_irq_enable(struct device *dev, unsigned int enabled)
222 {
223 return abx500_mask_and_set_register_interruptible(dev, AB8500_RTC,
224 AB8500_RTC_STAT_REG, RTC_ALARM_ENA,
225 enabled ? RTC_ALARM_ENA : 0);
226 }
227
228 static int ab8500_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
229 {
230 int retval, i;
231 unsigned char buf[ARRAY_SIZE(ab8500_rtc_alarm_regs)];
232 unsigned long mins, secs = 0, cursec = 0;
233 struct rtc_time curtm;
234
235 if (alarm->time.tm_year < (AB8500_RTC_EPOCH - 1900)) {
236 dev_dbg(dev, "year should be equal to or greater than %d\n",
237 AB8500_RTC_EPOCH);
238 return -EINVAL;
239 }
240
241 /* Get the number of seconds since 1970 */
242 rtc_tm_to_time(&alarm->time, &secs);
243
244 /*
245 * Check whether alarm is set less than 1min.
246 * Since our RTC doesn't support alarm resolution less than 1min,
247 * return -EINVAL, so UIE EMUL can take it up, incase of UIE_ON
248 */
249 ab8500_rtc_read_time(dev, &curtm); /* Read current time */
250 rtc_tm_to_time(&curtm, &cursec);
251 if ((secs - cursec) < 59) {
252 dev_dbg(dev, "Alarm less than 1 minute not supported\r\n");
253 return -EINVAL;
254 }
255
256 /*
257 * Convert it to the number of seconds since 01-01-2000 00:00:00, since
258 * we only have a small counter in the RTC.
259 */
260 secs -= get_elapsed_seconds(AB8500_RTC_EPOCH);
261
262 mins = secs / 60;
263
264 buf[2] = mins & 0xFF;
265 buf[1] = (mins >> 8) & 0xFF;
266 buf[0] = (mins >> 16) & 0xFF;
267
268 /* Set the alarm time */
269 for (i = 0; i < ARRAY_SIZE(ab8500_rtc_alarm_regs); i++) {
270 retval = abx500_set_register_interruptible(dev, AB8500_RTC,
271 ab8500_rtc_alarm_regs[i], buf[i]);
272 if (retval < 0)
273 return retval;
274 }
275
276 return ab8500_rtc_irq_enable(dev, alarm->enabled);
277 }
278
279 static int ab8540_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
280 {
281 int retval, i;
282 unsigned char buf[ARRAY_SIZE(ab8540_rtc_alarm_regs)];
283 unsigned long mins, secs = 0;
284
285 if (alarm->time.tm_year < (AB8500_RTC_EPOCH - 1900)) {
286 dev_dbg(dev, "year should be equal to or greater than %d\n",
287 AB8500_RTC_EPOCH);
288 return -EINVAL;
289 }
290
291 /* Get the number of seconds since 1970 */
292 rtc_tm_to_time(&alarm->time, &secs);
293
294 /*
295 * Convert it to the number of seconds since 01-01-2000 00:00:00
296 */
297 secs -= get_elapsed_seconds(AB8500_RTC_EPOCH);
298 mins = secs / 60;
299
300 buf[3] = secs % 60;
301 buf[2] = mins & 0xFF;
302 buf[1] = (mins >> 8) & 0xFF;
303 buf[0] = (mins >> 16) & 0xFF;
304
305 /* Set the alarm time */
306 for (i = 0; i < ARRAY_SIZE(ab8540_rtc_alarm_regs); i++) {
307 retval = abx500_set_register_interruptible(dev, AB8500_RTC,
308 ab8540_rtc_alarm_regs[i], buf[i]);
309 if (retval < 0)
310 return retval;
311 }
312
313 return ab8500_rtc_irq_enable(dev, alarm->enabled);
314 }
315
316 static int ab8500_rtc_set_calibration(struct device *dev, int calibration)
317 {
318 int retval;
319 u8 rtccal = 0;
320
321 /*
322 * Check that the calibration value (which is in units of 0.5
323 * parts-per-million) is in the AB8500's range for RtcCalibration
324 * register. -128 (0x80) is not permitted because the AB8500 uses
325 * a sign-bit rather than two's complement, so 0x80 is just another
326 * representation of zero.
327 */
328 if ((calibration < -127) || (calibration > 127)) {
329 dev_err(dev, "RtcCalibration value outside permitted range\n");
330 return -EINVAL;
331 }
332
333 /*
334 * The AB8500 uses sign (in bit7) and magnitude (in bits0-7)
335 * so need to convert to this sort of representation before writing
336 * into RtcCalibration register...
337 */
338 if (calibration >= 0)
339 rtccal = 0x7F & calibration;
340 else
341 rtccal = ~(calibration - 1) | 0x80;
342
343 retval = abx500_set_register_interruptible(dev, AB8500_RTC,
344 AB8500_RTC_CALIB_REG, rtccal);
345
346 return retval;
347 }
348
349 static int ab8500_rtc_get_calibration(struct device *dev, int *calibration)
350 {
351 int retval;
352 u8 rtccal = 0;
353
354 retval = abx500_get_register_interruptible(dev, AB8500_RTC,
355 AB8500_RTC_CALIB_REG, &rtccal);
356 if (retval >= 0) {
357 /*
358 * The AB8500 uses sign (in bit7) and magnitude (in bits0-7)
359 * so need to convert value from RtcCalibration register into
360 * a two's complement signed value...
361 */
362 if (rtccal & 0x80)
363 *calibration = 0 - (rtccal & 0x7F);
364 else
365 *calibration = 0x7F & rtccal;
366 }
367
368 return retval;
369 }
370
371 static ssize_t ab8500_sysfs_store_rtc_calibration(struct device *dev,
372 struct device_attribute *attr,
373 const char *buf, size_t count)
374 {
375 int retval;
376 int calibration = 0;
377
378 if (sscanf(buf, " %i ", &calibration) != 1) {
379 dev_err(dev, "Failed to store RTC calibration attribute\n");
380 return -EINVAL;
381 }
382
383 retval = ab8500_rtc_set_calibration(dev, calibration);
384
385 return retval ? retval : count;
386 }
387
388 static ssize_t ab8500_sysfs_show_rtc_calibration(struct device *dev,
389 struct device_attribute *attr, char *buf)
390 {
391 int retval = 0;
392 int calibration = 0;
393
394 retval = ab8500_rtc_get_calibration(dev, &calibration);
395 if (retval < 0) {
396 dev_err(dev, "Failed to read RTC calibration attribute\n");
397 sprintf(buf, "0\n");
398 return retval;
399 }
400
401 return sprintf(buf, "%d\n", calibration);
402 }
403
404 static DEVICE_ATTR(rtc_calibration, S_IRUGO | S_IWUSR,
405 ab8500_sysfs_show_rtc_calibration,
406 ab8500_sysfs_store_rtc_calibration);
407
408 static int ab8500_sysfs_rtc_register(struct device *dev)
409 {
410 return device_create_file(dev, &dev_attr_rtc_calibration);
411 }
412
413 static void ab8500_sysfs_rtc_unregister(struct device *dev)
414 {
415 device_remove_file(dev, &dev_attr_rtc_calibration);
416 }
417
418 static irqreturn_t rtc_alarm_handler(int irq, void *data)
419 {
420 struct rtc_device *rtc = data;
421 unsigned long events = RTC_IRQF | RTC_AF;
422
423 dev_dbg(&rtc->dev, "%s\n", __func__);
424 rtc_update_irq(rtc, 1, events);
425
426 return IRQ_HANDLED;
427 }
428
429 static const struct rtc_class_ops ab8500_rtc_ops = {
430 .read_time = ab8500_rtc_read_time,
431 .set_time = ab8500_rtc_set_time,
432 .read_alarm = ab8500_rtc_read_alarm,
433 .set_alarm = ab8500_rtc_set_alarm,
434 .alarm_irq_enable = ab8500_rtc_irq_enable,
435 };
436
437 static const struct rtc_class_ops ab8540_rtc_ops = {
438 .read_time = ab8500_rtc_read_time,
439 .set_time = ab8500_rtc_set_time,
440 .read_alarm = ab8500_rtc_read_alarm,
441 .set_alarm = ab8540_rtc_set_alarm,
442 .alarm_irq_enable = ab8500_rtc_irq_enable,
443 };
444
445 static struct platform_device_id ab85xx_rtc_ids[] = {
446 { "ab8500-rtc", (kernel_ulong_t)&ab8500_rtc_ops, },
447 { "ab8540-rtc", (kernel_ulong_t)&ab8540_rtc_ops, },
448 };
449
450 static int ab8500_rtc_probe(struct platform_device *pdev)
451 {
452 const struct platform_device_id *platid = platform_get_device_id(pdev);
453 int err;
454 struct rtc_device *rtc;
455 u8 rtc_ctrl;
456 int irq;
457
458 irq = platform_get_irq_byname(pdev, "ALARM");
459 if (irq < 0)
460 return irq;
461
462 /* For RTC supply test */
463 err = abx500_mask_and_set_register_interruptible(&pdev->dev, AB8500_RTC,
464 AB8500_RTC_STAT_REG, RTC_STATUS_DATA, RTC_STATUS_DATA);
465 if (err < 0)
466 return err;
467
468 /* Wait for reset by the PorRtc */
469 usleep_range(1000, 5000);
470
471 err = abx500_get_register_interruptible(&pdev->dev, AB8500_RTC,
472 AB8500_RTC_STAT_REG, &rtc_ctrl);
473 if (err < 0)
474 return err;
475
476 /* Check if the RTC Supply fails */
477 if (!(rtc_ctrl & RTC_STATUS_DATA)) {
478 dev_err(&pdev->dev, "RTC supply failure\n");
479 return -ENODEV;
480 }
481
482 device_init_wakeup(&pdev->dev, true);
483
484 rtc = devm_rtc_device_register(&pdev->dev, "ab8500-rtc",
485 (struct rtc_class_ops *)platid->driver_data,
486 THIS_MODULE);
487 if (IS_ERR(rtc)) {
488 dev_err(&pdev->dev, "Registration failed\n");
489 err = PTR_ERR(rtc);
490 return err;
491 }
492
493 err = devm_request_threaded_irq(&pdev->dev, irq, NULL,
494 rtc_alarm_handler, IRQF_NO_SUSPEND | IRQF_ONESHOT,
495 "ab8500-rtc", rtc);
496 if (err < 0)
497 return err;
498
499 platform_set_drvdata(pdev, rtc);
500
501 err = ab8500_sysfs_rtc_register(&pdev->dev);
502 if (err) {
503 dev_err(&pdev->dev, "sysfs RTC failed to register\n");
504 return err;
505 }
506
507 rtc->uie_unsupported = 1;
508
509 return 0;
510 }
511
512 static int ab8500_rtc_remove(struct platform_device *pdev)
513 {
514 ab8500_sysfs_rtc_unregister(&pdev->dev);
515
516 return 0;
517 }
518
519 static struct platform_driver ab8500_rtc_driver = {
520 .driver = {
521 .name = "ab8500-rtc",
522 },
523 .probe = ab8500_rtc_probe,
524 .remove = ab8500_rtc_remove,
525 .id_table = ab85xx_rtc_ids,
526 };
527
528 module_platform_driver(ab8500_rtc_driver);
529
530 MODULE_AUTHOR("Virupax Sadashivpetimath <virupax.sadashivpetimath@stericsson.com>");
531 MODULE_DESCRIPTION("AB8500 RTC Driver");
532 MODULE_LICENSE("GPL v2");
Linux with added FPC-III support