tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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#include <linux/pm_wakeirq.h>
22
23#define AB8500_RTC_SOFF_STAT_REG 0x00
24#define AB8500_RTC_CC_CONF_REG 0x01
25#define AB8500_RTC_READ_REQ_REG 0x02
26#define AB8500_RTC_WATCH_TSECMID_REG 0x03
27#define AB8500_RTC_WATCH_TSECHI_REG 0x04
28#define AB8500_RTC_WATCH_TMIN_LOW_REG 0x05
29#define AB8500_RTC_WATCH_TMIN_MID_REG 0x06
30#define AB8500_RTC_WATCH_TMIN_HI_REG 0x07
31#define AB8500_RTC_ALRM_MIN_LOW_REG 0x08
32#define AB8500_RTC_ALRM_MIN_MID_REG 0x09
33#define AB8500_RTC_ALRM_MIN_HI_REG 0x0A
34#define AB8500_RTC_STAT_REG 0x0B
35#define AB8500_RTC_BKUP_CHG_REG 0x0C
36#define AB8500_RTC_FORCE_BKUP_REG 0x0D
37#define AB8500_RTC_CALIB_REG 0x0E
38#define AB8500_RTC_SWITCH_STAT_REG 0x0F
39#define AB8540_RTC_ALRM_SEC 0x22
40#define AB8540_RTC_ALRM_MIN_LOW_REG 0x23
41#define AB8540_RTC_ALRM_MIN_MID_REG 0x24
42#define AB8540_RTC_ALRM_MIN_HI_REG 0x25
43
44/* RtcReadRequest bits */
45#define RTC_READ_REQUEST 0x01
46#define RTC_WRITE_REQUEST 0x02
47
48/* RtcCtrl bits */
49#define RTC_ALARM_ENA 0x04
50#define RTC_STATUS_DATA 0x01
51
52#define COUNTS_PER_SEC (0xF000 / 60)
53#define AB8500_RTC_EPOCH 2000
54
55static const u8 ab8500_rtc_time_regs[] = {
56 AB8500_RTC_WATCH_TMIN_HI_REG, AB8500_RTC_WATCH_TMIN_MID_REG,
57 AB8500_RTC_WATCH_TMIN_LOW_REG, AB8500_RTC_WATCH_TSECHI_REG,
58 AB8500_RTC_WATCH_TSECMID_REG
59};
60
61static const u8 ab8500_rtc_alarm_regs[] = {
62 AB8500_RTC_ALRM_MIN_HI_REG, AB8500_RTC_ALRM_MIN_MID_REG,
63 AB8500_RTC_ALRM_MIN_LOW_REG
64};
65
66static const u8 ab8540_rtc_alarm_regs[] = {
67 AB8540_RTC_ALRM_MIN_HI_REG, AB8540_RTC_ALRM_MIN_MID_REG,
68 AB8540_RTC_ALRM_MIN_LOW_REG, AB8540_RTC_ALRM_SEC
69};
70
71/* Calculate the seconds from 1970 to 01-01-2000 00:00:00 */
72static unsigned long get_elapsed_seconds(int year)
73{
74 unsigned long secs;
75 struct rtc_time tm = {
76 .tm_year = year - 1900,
77 .tm_mday = 1,
78 };
79
80 /*
81 * This function calculates secs from 1970 and not from
82 * 1900, even if we supply the offset from year 1900.
83 */
84 rtc_tm_to_time(&tm, &secs);
85 return secs;
86}
87
88static int ab8500_rtc_read_time(struct device *dev, struct rtc_time *tm)
89{
90 unsigned long timeout = jiffies + HZ;
91 int retval, i;
92 unsigned long mins, secs;
93 unsigned char buf[ARRAY_SIZE(ab8500_rtc_time_regs)];
94 u8 value;
95
96 /* Request a data read */
97 retval = abx500_set_register_interruptible(dev,
98 AB8500_RTC, AB8500_RTC_READ_REQ_REG, RTC_READ_REQUEST);
99 if (retval < 0)
100 return retval;
101
102 /* Wait for some cycles after enabling the rtc read in ab8500 */
103 while (time_before(jiffies, timeout)) {
104 retval = abx500_get_register_interruptible(dev,
105 AB8500_RTC, AB8500_RTC_READ_REQ_REG, &value);
106 if (retval < 0)
107 return retval;
108
109 if (!(value & RTC_READ_REQUEST))
110 break;
111
112 usleep_range(1000, 5000);
113 }
114
115 /* Read the Watchtime registers */
116 for (i = 0; i < ARRAY_SIZE(ab8500_rtc_time_regs); i++) {
117 retval = abx500_get_register_interruptible(dev,
118 AB8500_RTC, ab8500_rtc_time_regs[i], &value);
119 if (retval < 0)
120 return retval;
121 buf[i] = value;
122 }
123
124 mins = (buf[0] << 16) | (buf[1] << 8) | buf[2];
125
126 secs = (buf[3] << 8) | buf[4];
127 secs = secs / COUNTS_PER_SEC;
128 secs = secs + (mins * 60);
129
130 /* Add back the initially subtracted number of seconds */
131 secs += get_elapsed_seconds(AB8500_RTC_EPOCH);
132
133 rtc_time_to_tm(secs, tm);
134 return rtc_valid_tm(tm);
135}
136
137static int ab8500_rtc_set_time(struct device *dev, struct rtc_time *tm)
138{
139 int retval, i;
140 unsigned char buf[ARRAY_SIZE(ab8500_rtc_time_regs)];
141 unsigned long no_secs, no_mins, secs = 0;
142
143 if (tm->tm_year < (AB8500_RTC_EPOCH - 1900)) {
144 dev_dbg(dev, "year should be equal to or greater than %d\n",
145 AB8500_RTC_EPOCH);
146 return -EINVAL;
147 }
148
149 /* Get the number of seconds since 1970 */
150 rtc_tm_to_time(tm, &secs);
151
152 /*
153 * Convert it to the number of seconds since 01-01-2000 00:00:00, since
154 * we only have a small counter in the RTC.
155 */
156 secs -= get_elapsed_seconds(AB8500_RTC_EPOCH);
157
158 no_mins = secs / 60;
159
160 no_secs = secs % 60;
161 /* Make the seconds count as per the RTC resolution */
162 no_secs = no_secs * COUNTS_PER_SEC;
163
164 buf[4] = no_secs & 0xFF;
165 buf[3] = (no_secs >> 8) & 0xFF;
166
167 buf[2] = no_mins & 0xFF;
168 buf[1] = (no_mins >> 8) & 0xFF;
169 buf[0] = (no_mins >> 16) & 0xFF;
170
171 for (i = 0; i < ARRAY_SIZE(ab8500_rtc_time_regs); i++) {
172 retval = abx500_set_register_interruptible(dev, AB8500_RTC,
173 ab8500_rtc_time_regs[i], buf[i]);
174 if (retval < 0)
175 return retval;
176 }
177
178 /* Request a data write */
179 return abx500_set_register_interruptible(dev, AB8500_RTC,
180 AB8500_RTC_READ_REQ_REG, RTC_WRITE_REQUEST);
181}
182
183static int ab8500_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
184{
185 int retval, i;
186 u8 rtc_ctrl, value;
187 unsigned char buf[ARRAY_SIZE(ab8500_rtc_alarm_regs)];
188 unsigned long secs, mins;
189
190 /* Check if the alarm is enabled or not */
191 retval = abx500_get_register_interruptible(dev, AB8500_RTC,
192 AB8500_RTC_STAT_REG, &rtc_ctrl);
193 if (retval < 0)
194 return retval;
195
196 if (rtc_ctrl & RTC_ALARM_ENA)
197 alarm->enabled = 1;
198 else
199 alarm->enabled = 0;
200
201 alarm->pending = 0;
202
203 for (i = 0; i < ARRAY_SIZE(ab8500_rtc_alarm_regs); i++) {
204 retval = abx500_get_register_interruptible(dev, AB8500_RTC,
205 ab8500_rtc_alarm_regs[i], &value);
206 if (retval < 0)
207 return retval;
208 buf[i] = value;
209 }
210
211 mins = (buf[0] << 16) | (buf[1] << 8) | (buf[2]);
212 secs = mins * 60;
213
214 /* Add back the initially subtracted number of seconds */
215 secs += get_elapsed_seconds(AB8500_RTC_EPOCH);
216
217 rtc_time_to_tm(secs, &alarm->time);
218
219 return rtc_valid_tm(&alarm->time);
220}
221
222static int ab8500_rtc_irq_enable(struct device *dev, unsigned int enabled)
223{
224 return abx500_mask_and_set_register_interruptible(dev, AB8500_RTC,
225 AB8500_RTC_STAT_REG, RTC_ALARM_ENA,
226 enabled ? RTC_ALARM_ENA : 0);
227}
228
229static int ab8500_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
230{
231 int retval, i;
232 unsigned char buf[ARRAY_SIZE(ab8500_rtc_alarm_regs)];
233 unsigned long mins, secs = 0, cursec = 0;
234 struct rtc_time curtm;
235
236 if (alarm->time.tm_year < (AB8500_RTC_EPOCH - 1900)) {
237 dev_dbg(dev, "year should be equal to or greater than %d\n",
238 AB8500_RTC_EPOCH);
239 return -EINVAL;
240 }
241
242 /* Get the number of seconds since 1970 */
243 rtc_tm_to_time(&alarm->time, &secs);
244
245 /*
246 * Check whether alarm is set less than 1min.
247 * Since our RTC doesn't support alarm resolution less than 1min,
248 * return -EINVAL, so UIE EMUL can take it up, incase of UIE_ON
249 */
250 ab8500_rtc_read_time(dev, &curtm); /* Read current time */
251 rtc_tm_to_time(&curtm, &cursec);
252 if ((secs - cursec) < 59) {
253 dev_dbg(dev, "Alarm less than 1 minute not supported\r\n");
254 return -EINVAL;
255 }
256
257 /*
258 * Convert it to the number of seconds since 01-01-2000 00:00:00, since
259 * we only have a small counter in the RTC.
260 */
261 secs -= get_elapsed_seconds(AB8500_RTC_EPOCH);
262
263 mins = secs / 60;
264
265 buf[2] = mins & 0xFF;
266 buf[1] = (mins >> 8) & 0xFF;
267 buf[0] = (mins >> 16) & 0xFF;
268
269 /* Set the alarm time */
270 for (i = 0; i < ARRAY_SIZE(ab8500_rtc_alarm_regs); i++) {
271 retval = abx500_set_register_interruptible(dev, AB8500_RTC,
272 ab8500_rtc_alarm_regs[i], buf[i]);
273 if (retval < 0)
274 return retval;
275 }
276
277 return ab8500_rtc_irq_enable(dev, alarm->enabled);
278}
279
280static int ab8540_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
281{
282 int retval, i;
283 unsigned char buf[ARRAY_SIZE(ab8540_rtc_alarm_regs)];
284 unsigned long mins, secs = 0;
285
286 if (alarm->time.tm_year < (AB8500_RTC_EPOCH - 1900)) {
287 dev_dbg(dev, "year should be equal to or greater than %d\n",
288 AB8500_RTC_EPOCH);
289 return -EINVAL;
290 }
291
292 /* Get the number of seconds since 1970 */
293 rtc_tm_to_time(&alarm->time, &secs);
294
295 /*
296 * Convert it to the number of seconds since 01-01-2000 00:00:00
297 */
298 secs -= get_elapsed_seconds(AB8500_RTC_EPOCH);
299 mins = secs / 60;
300
301 buf[3] = secs % 60;
302 buf[2] = mins & 0xFF;
303 buf[1] = (mins >> 8) & 0xFF;
304 buf[0] = (mins >> 16) & 0xFF;
305
306 /* Set the alarm time */
307 for (i = 0; i < ARRAY_SIZE(ab8540_rtc_alarm_regs); i++) {
308 retval = abx500_set_register_interruptible(dev, AB8500_RTC,
309 ab8540_rtc_alarm_regs[i], buf[i]);
310 if (retval < 0)
311 return retval;
312 }
313
314 return ab8500_rtc_irq_enable(dev, alarm->enabled);
315}
316
317static int ab8500_rtc_set_calibration(struct device *dev, int calibration)
318{
319 int retval;
320 u8 rtccal = 0;
321
322 /*
323 * Check that the calibration value (which is in units of 0.5
324 * parts-per-million) is in the AB8500's range for RtcCalibration
325 * register. -128 (0x80) is not permitted because the AB8500 uses
326 * a sign-bit rather than two's complement, so 0x80 is just another
327 * representation of zero.
328 */
329 if ((calibration < -127) || (calibration > 127)) {
330 dev_err(dev, "RtcCalibration value outside permitted range\n");
331 return -EINVAL;
332 }
333
334 /*
335 * The AB8500 uses sign (in bit7) and magnitude (in bits0-7)
336 * so need to convert to this sort of representation before writing
337 * into RtcCalibration register...
338 */
339 if (calibration >= 0)
340 rtccal = 0x7F & calibration;
341 else
342 rtccal = ~(calibration - 1) | 0x80;
343
344 retval = abx500_set_register_interruptible(dev, AB8500_RTC,
345 AB8500_RTC_CALIB_REG, rtccal);
346
347 return retval;
348}
349
350static int ab8500_rtc_get_calibration(struct device *dev, int *calibration)
351{
352 int retval;
353 u8 rtccal = 0;
354
355 retval = abx500_get_register_interruptible(dev, AB8500_RTC,
356 AB8500_RTC_CALIB_REG, &rtccal);
357 if (retval >= 0) {
358 /*
359 * The AB8500 uses sign (in bit7) and magnitude (in bits0-7)
360 * so need to convert value from RtcCalibration register into
361 * a two's complement signed value...
362 */
363 if (rtccal & 0x80)
364 *calibration = 0 - (rtccal & 0x7F);
365 else
366 *calibration = 0x7F & rtccal;
367 }
368
369 return retval;
370}
371
372static ssize_t ab8500_sysfs_store_rtc_calibration(struct device *dev,
373 struct device_attribute *attr,
374 const char *buf, size_t count)
375{
376 int retval;
377 int calibration = 0;
378
379 if (sscanf(buf, " %i ", &calibration) != 1) {
380 dev_err(dev, "Failed to store RTC calibration attribute\n");
381 return -EINVAL;
382 }
383
384 retval = ab8500_rtc_set_calibration(dev, calibration);
385
386 return retval ? retval : count;
387}
388
389static ssize_t ab8500_sysfs_show_rtc_calibration(struct device *dev,
390 struct device_attribute *attr, char *buf)
391{
392 int retval = 0;
393 int calibration = 0;
394
395 retval = ab8500_rtc_get_calibration(dev, &calibration);
396 if (retval < 0) {
397 dev_err(dev, "Failed to read RTC calibration attribute\n");
398 sprintf(buf, "0\n");
399 return retval;
400 }
401
402 return sprintf(buf, "%d\n", calibration);
403}
404
405static DEVICE_ATTR(rtc_calibration, S_IRUGO | S_IWUSR,
406 ab8500_sysfs_show_rtc_calibration,
407 ab8500_sysfs_store_rtc_calibration);
408
409static int ab8500_sysfs_rtc_register(struct device *dev)
410{
411 return device_create_file(dev, &dev_attr_rtc_calibration);
412}
413
414static void ab8500_sysfs_rtc_unregister(struct device *dev)
415{
416 device_remove_file(dev, &dev_attr_rtc_calibration);
417}
418
419static irqreturn_t rtc_alarm_handler(int irq, void *data)
420{
421 struct rtc_device *rtc = data;
422 unsigned long events = RTC_IRQF | RTC_AF;
423
424 dev_dbg(&rtc->dev, "%s\n", __func__);
425 rtc_update_irq(rtc, 1, events);
426
427 return IRQ_HANDLED;
428}
429
430static const struct rtc_class_ops ab8500_rtc_ops = {
431 .read_time = ab8500_rtc_read_time,
432 .set_time = ab8500_rtc_set_time,
433 .read_alarm = ab8500_rtc_read_alarm,
434 .set_alarm = ab8500_rtc_set_alarm,
435 .alarm_irq_enable = ab8500_rtc_irq_enable,
436};
437
438static const struct rtc_class_ops ab8540_rtc_ops = {
439 .read_time = ab8500_rtc_read_time,
440 .set_time = ab8500_rtc_set_time,
441 .read_alarm = ab8500_rtc_read_alarm,
442 .set_alarm = ab8540_rtc_set_alarm,
443 .alarm_irq_enable = ab8500_rtc_irq_enable,
444};
445
446static const struct platform_device_id ab85xx_rtc_ids[] = {
447 { "ab8500-rtc", (kernel_ulong_t)&ab8500_rtc_ops, },
448 { "ab8540-rtc", (kernel_ulong_t)&ab8540_rtc_ops, },
449 { /* sentinel */ }
450};
451MODULE_DEVICE_TABLE(platform, ab85xx_rtc_ids);
452
453static int ab8500_rtc_probe(struct platform_device *pdev)
454{
455 const struct platform_device_id *platid = platform_get_device_id(pdev);
456 int err;
457 struct rtc_device *rtc;
458 u8 rtc_ctrl;
459 int irq;
460
461 irq = platform_get_irq_byname(pdev, "ALARM");
462 if (irq < 0)
463 return irq;
464
465 /* For RTC supply test */
466 err = abx500_mask_and_set_register_interruptible(&pdev->dev, AB8500_RTC,
467 AB8500_RTC_STAT_REG, RTC_STATUS_DATA, RTC_STATUS_DATA);
468 if (err < 0)
469 return err;
470
471 /* Wait for reset by the PorRtc */
472 usleep_range(1000, 5000);
473
474 err = abx500_get_register_interruptible(&pdev->dev, AB8500_RTC,
475 AB8500_RTC_STAT_REG, &rtc_ctrl);
476 if (err < 0)
477 return err;
478
479 /* Check if the RTC Supply fails */
480 if (!(rtc_ctrl & RTC_STATUS_DATA)) {
481 dev_err(&pdev->dev, "RTC supply failure\n");
482 return -ENODEV;
483 }
484
485 device_init_wakeup(&pdev->dev, true);
486
487 rtc = devm_rtc_device_register(&pdev->dev, "ab8500-rtc",
488 (struct rtc_class_ops *)platid->driver_data,
489 THIS_MODULE);
490 if (IS_ERR(rtc)) {
491 dev_err(&pdev->dev, "Registration failed\n");
492 err = PTR_ERR(rtc);
493 return err;
494 }
495
496 err = devm_request_threaded_irq(&pdev->dev, irq, NULL,
497 rtc_alarm_handler, IRQF_ONESHOT,
498 "ab8500-rtc", rtc);
499 if (err < 0)
500 return err;
501
502 dev_pm_set_wake_irq(&pdev->dev, irq);
503 platform_set_drvdata(pdev, rtc);
504
505 err = ab8500_sysfs_rtc_register(&pdev->dev);
506 if (err) {
507 dev_err(&pdev->dev, "sysfs RTC failed to register\n");
508 return err;
509 }
510
511 rtc->uie_unsupported = 1;
512
513 return 0;
514}
515
516static int ab8500_rtc_remove(struct platform_device *pdev)
517{
518 dev_pm_clear_wake_irq(&pdev->dev);
519 device_init_wakeup(&pdev->dev, false);
520 ab8500_sysfs_rtc_unregister(&pdev->dev);
521
522 return 0;
523}
524
525static struct platform_driver ab8500_rtc_driver = {
526 .driver = {
527 .name = "ab8500-rtc",
528 },
529 .probe = ab8500_rtc_probe,
530 .remove = ab8500_rtc_remove,
531 .id_table = ab85xx_rtc_ids,
532};
533
534module_platform_driver(ab8500_rtc_driver);
535
536MODULE_AUTHOR("Virupax Sadashivpetimath <virupax.sadashivpetimath@stericsson.com>");
537MODULE_DESCRIPTION("AB8500 RTC Driver");
538MODULE_LICENSE("GPL v2");