2 * Copyright (C) ST-Ericsson SA 2010
4 * License terms: GNU General Public License (GPL) version 2
5 * Author: Virupax Sadashivpetimath <virupax.sadashivpetimath@stericsson.com>
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>
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>
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
39 /* RtcReadRequest bits */
40 #define RTC_READ_REQUEST 0x01
41 #define RTC_WRITE_REQUEST 0x02
44 #define RTC_ALARM_ENA 0x04
45 #define RTC_STATUS_DATA 0x01
47 #define COUNTS_PER_SEC (0xF000 / 60)
48 #define AB8500_RTC_EPOCH 2000
50 static const u8 ab8500_rtc_time_regs[] = {
51 AB8500_RTC_WATCH_TMIN_HI_REG, AB8500_RTC_WATCH_TMIN_MID_REG,
52 AB8500_RTC_WATCH_TMIN_LOW_REG, AB8500_RTC_WATCH_TSECHI_REG,
53 AB8500_RTC_WATCH_TSECMID_REG
56 static const u8 ab8500_rtc_alarm_regs[] = {
57 AB8500_RTC_ALRM_MIN_HI_REG, AB8500_RTC_ALRM_MIN_MID_REG,
58 AB8500_RTC_ALRM_MIN_LOW_REG
61 /* Calculate the seconds from 1970 to 01-01-2000 00:00:00 */
62 static unsigned long get_elapsed_seconds(int year)
65 struct rtc_time tm = {
66 .tm_year = year - 1900,
71 * This function calculates secs from 1970 and not from
72 * 1900, even if we supply the offset from year 1900.
74 rtc_tm_to_time(&tm, &secs);
78 static int ab8500_rtc_read_time(struct device *dev, struct rtc_time *tm)
80 unsigned long timeout = jiffies + HZ;
82 unsigned long mins, secs;
83 unsigned char buf[ARRAY_SIZE(ab8500_rtc_time_regs)];
86 /* Request a data read */
87 retval = abx500_set_register_interruptible(dev,
88 AB8500_RTC, AB8500_RTC_READ_REQ_REG, RTC_READ_REQUEST);
92 /* Early AB8500 chips will not clear the rtc read request bit */
93 if (abx500_get_chip_id(dev) == 0) {
94 usleep_range(1000, 1000);
96 /* Wait for some cycles after enabling the rtc read in ab8500 */
97 while (time_before(jiffies, timeout)) {
98 retval = abx500_get_register_interruptible(dev,
99 AB8500_RTC, AB8500_RTC_READ_REQ_REG, &value);
103 if (!(value & RTC_READ_REQUEST))
106 usleep_range(1000, 5000);
110 /* Read the Watchtime registers */
111 for (i = 0; i < ARRAY_SIZE(ab8500_rtc_time_regs); i++) {
112 retval = abx500_get_register_interruptible(dev,
113 AB8500_RTC, ab8500_rtc_time_regs[i], &value);
119 mins = (buf[0] << 16) | (buf[1] << 8) | buf[2];
121 secs = (buf[3] << 8) | buf[4];
122 secs = secs / COUNTS_PER_SEC;
123 secs = secs + (mins * 60);
125 /* Add back the initially subtracted number of seconds */
126 secs += get_elapsed_seconds(AB8500_RTC_EPOCH);
128 rtc_time_to_tm(secs, tm);
129 return rtc_valid_tm(tm);
132 static int ab8500_rtc_set_time(struct device *dev, struct rtc_time *tm)
135 unsigned char buf[ARRAY_SIZE(ab8500_rtc_time_regs)];
136 unsigned long no_secs, no_mins, secs = 0;
138 if (tm->tm_year < (AB8500_RTC_EPOCH - 1900)) {
139 dev_dbg(dev, "year should be equal to or greater than %d\n",
144 /* Get the number of seconds since 1970 */
145 rtc_tm_to_time(tm, &secs);
148 * Convert it to the number of seconds since 01-01-2000 00:00:00, since
149 * we only have a small counter in the RTC.
151 secs -= get_elapsed_seconds(AB8500_RTC_EPOCH);
156 /* Make the seconds count as per the RTC resolution */
157 no_secs = no_secs * COUNTS_PER_SEC;
159 buf[4] = no_secs & 0xFF;
160 buf[3] = (no_secs >> 8) & 0xFF;
162 buf[2] = no_mins & 0xFF;
163 buf[1] = (no_mins >> 8) & 0xFF;
164 buf[0] = (no_mins >> 16) & 0xFF;
166 for (i = 0; i < ARRAY_SIZE(ab8500_rtc_time_regs); i++) {
167 retval = abx500_set_register_interruptible(dev, AB8500_RTC,
168 ab8500_rtc_time_regs[i], buf[i]);
173 /* Request a data write */
174 return abx500_set_register_interruptible(dev, AB8500_RTC,
175 AB8500_RTC_READ_REQ_REG, RTC_WRITE_REQUEST);
178 static int ab8500_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
182 unsigned char buf[ARRAY_SIZE(ab8500_rtc_alarm_regs)];
183 unsigned long secs, mins;
185 /* Check if the alarm is enabled or not */
186 retval = abx500_get_register_interruptible(dev, AB8500_RTC,
187 AB8500_RTC_STAT_REG, &rtc_ctrl);
191 if (rtc_ctrl & RTC_ALARM_ENA)
198 for (i = 0; i < ARRAY_SIZE(ab8500_rtc_alarm_regs); i++) {
199 retval = abx500_get_register_interruptible(dev, AB8500_RTC,
200 ab8500_rtc_alarm_regs[i], &value);
206 mins = (buf[0] << 16) | (buf[1] << 8) | (buf[2]);
209 /* Add back the initially subtracted number of seconds */
210 secs += get_elapsed_seconds(AB8500_RTC_EPOCH);
212 rtc_time_to_tm(secs, &alarm->time);
214 return rtc_valid_tm(&alarm->time);
217 static int ab8500_rtc_irq_enable(struct device *dev, unsigned int enabled)
219 return abx500_mask_and_set_register_interruptible(dev, AB8500_RTC,
220 AB8500_RTC_STAT_REG, RTC_ALARM_ENA,
221 enabled ? RTC_ALARM_ENA : 0);
224 static int ab8500_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
227 unsigned char buf[ARRAY_SIZE(ab8500_rtc_alarm_regs)];
228 unsigned long mins, secs = 0;
230 if (alarm->time.tm_year < (AB8500_RTC_EPOCH - 1900)) {
231 dev_dbg(dev, "year should be equal to or greater than %d\n",
236 /* Get the number of seconds since 1970 */
237 rtc_tm_to_time(&alarm->time, &secs);
240 * Convert it to the number of seconds since 01-01-2000 00:00:00, since
241 * we only have a small counter in the RTC.
243 secs -= get_elapsed_seconds(AB8500_RTC_EPOCH);
247 buf[2] = mins & 0xFF;
248 buf[1] = (mins >> 8) & 0xFF;
249 buf[0] = (mins >> 16) & 0xFF;
251 /* Set the alarm time */
252 for (i = 0; i < ARRAY_SIZE(ab8500_rtc_alarm_regs); i++) {
253 retval = abx500_set_register_interruptible(dev, AB8500_RTC,
254 ab8500_rtc_alarm_regs[i], buf[i]);
259 return ab8500_rtc_irq_enable(dev, alarm->enabled);
263 static int ab8500_rtc_set_calibration(struct device *dev, int calibration)
269 * Check that the calibration value (which is in units of 0.5
270 * parts-per-million) is in the AB8500's range for RtcCalibration
271 * register. -128 (0x80) is not permitted because the AB8500 uses
272 * a sign-bit rather than two's complement, so 0x80 is just another
273 * representation of zero.
275 if ((calibration < -127) || (calibration > 127)) {
276 dev_err(dev, "RtcCalibration value outside permitted range\n");
281 * The AB8500 uses sign (in bit7) and magnitude (in bits0-7)
282 * so need to convert to this sort of representation before writing
283 * into RtcCalibration register...
285 if (calibration >= 0)
286 rtccal = 0x7F & calibration;
288 rtccal = ~(calibration - 1) | 0x80;
290 retval = abx500_set_register_interruptible(dev, AB8500_RTC,
291 AB8500_RTC_CALIB_REG, rtccal);
296 static int ab8500_rtc_get_calibration(struct device *dev, int *calibration)
301 retval = abx500_get_register_interruptible(dev, AB8500_RTC,
302 AB8500_RTC_CALIB_REG, &rtccal);
305 * The AB8500 uses sign (in bit7) and magnitude (in bits0-7)
306 * so need to convert value from RtcCalibration register into
307 * a two's complement signed value...
310 *calibration = 0 - (rtccal & 0x7F);
312 *calibration = 0x7F & rtccal;
318 static ssize_t ab8500_sysfs_store_rtc_calibration(struct device *dev,
319 struct device_attribute *attr,
320 const char *buf, size_t count)
325 if (sscanf(buf, " %i ", &calibration) != 1) {
326 dev_err(dev, "Failed to store RTC calibration attribute\n");
330 retval = ab8500_rtc_set_calibration(dev, calibration);
332 return retval ? retval : count;
335 static ssize_t ab8500_sysfs_show_rtc_calibration(struct device *dev,
336 struct device_attribute *attr, char *buf)
341 retval = ab8500_rtc_get_calibration(dev, &calibration);
343 dev_err(dev, "Failed to read RTC calibration attribute\n");
348 return sprintf(buf, "%d\n", calibration);
351 static DEVICE_ATTR(rtc_calibration, S_IRUGO | S_IWUSR,
352 ab8500_sysfs_show_rtc_calibration,
353 ab8500_sysfs_store_rtc_calibration);
355 static int ab8500_sysfs_rtc_register(struct device *dev)
357 return device_create_file(dev, &dev_attr_rtc_calibration);
360 static void ab8500_sysfs_rtc_unregister(struct device *dev)
362 device_remove_file(dev, &dev_attr_rtc_calibration);
365 static irqreturn_t rtc_alarm_handler(int irq, void *data)
367 struct rtc_device *rtc = data;
368 unsigned long events = RTC_IRQF | RTC_AF;
370 dev_dbg(&rtc->dev, "%s\n", __func__);
371 rtc_update_irq(rtc, 1, events);
376 static const struct rtc_class_ops ab8500_rtc_ops = {
377 .read_time = ab8500_rtc_read_time,
378 .set_time = ab8500_rtc_set_time,
379 .read_alarm = ab8500_rtc_read_alarm,
380 .set_alarm = ab8500_rtc_set_alarm,
381 .alarm_irq_enable = ab8500_rtc_irq_enable,
384 static int __devinit ab8500_rtc_probe(struct platform_device *pdev)
387 struct rtc_device *rtc;
391 irq = platform_get_irq_byname(pdev, "ALARM");
395 /* For RTC supply test */
396 err = abx500_mask_and_set_register_interruptible(&pdev->dev, AB8500_RTC,
397 AB8500_RTC_STAT_REG, RTC_STATUS_DATA, RTC_STATUS_DATA);
401 /* Wait for reset by the PorRtc */
402 usleep_range(1000, 5000);
404 err = abx500_get_register_interruptible(&pdev->dev, AB8500_RTC,
405 AB8500_RTC_STAT_REG, &rtc_ctrl);
409 /* Check if the RTC Supply fails */
410 if (!(rtc_ctrl & RTC_STATUS_DATA)) {
411 dev_err(&pdev->dev, "RTC supply failure\n");
415 device_init_wakeup(&pdev->dev, true);
417 rtc = rtc_device_register("ab8500-rtc", &pdev->dev, &ab8500_rtc_ops,
420 dev_err(&pdev->dev, "Registration failed\n");
425 err = request_threaded_irq(irq, NULL, rtc_alarm_handler,
426 IRQF_NO_SUSPEND | IRQF_ONESHOT, "ab8500-rtc", rtc);
428 rtc_device_unregister(rtc);
432 platform_set_drvdata(pdev, rtc);
434 err = ab8500_sysfs_rtc_register(&pdev->dev);
436 dev_err(&pdev->dev, "sysfs RTC failed to register\n");
443 static int __devexit ab8500_rtc_remove(struct platform_device *pdev)
445 struct rtc_device *rtc = platform_get_drvdata(pdev);
446 int irq = platform_get_irq_byname(pdev, "ALARM");
448 ab8500_sysfs_rtc_unregister(&pdev->dev);
451 rtc_device_unregister(rtc);
452 platform_set_drvdata(pdev, NULL);
457 static const struct of_device_id ab8500_rtc_match[] = {
458 { .compatible = "stericsson,ab8500-rtc", },
462 static struct platform_driver ab8500_rtc_driver = {
464 .name = "ab8500-rtc",
465 .owner = THIS_MODULE,
466 .of_match_table = ab8500_rtc_match,
468 .probe = ab8500_rtc_probe,
469 .remove = __devexit_p(ab8500_rtc_remove),
472 module_platform_driver(ab8500_rtc_driver);
474 MODULE_AUTHOR("Virupax Sadashivpetimath <virupax.sadashivpetimath@stericsson.com>");
475 MODULE_DESCRIPTION("AB8500 RTC Driver");
476 MODULE_LICENSE("GPL v2");