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/ab8500.h>
19 #include <linux/delay.h>
21 #define AB8500_RTC_SOFF_STAT_REG 0x00
22 #define AB8500_RTC_CC_CONF_REG 0x01
23 #define AB8500_RTC_READ_REQ_REG 0x02
24 #define AB8500_RTC_WATCH_TSECMID_REG 0x03
25 #define AB8500_RTC_WATCH_TSECHI_REG 0x04
26 #define AB8500_RTC_WATCH_TMIN_LOW_REG 0x05
27 #define AB8500_RTC_WATCH_TMIN_MID_REG 0x06
28 #define AB8500_RTC_WATCH_TMIN_HI_REG 0x07
29 #define AB8500_RTC_ALRM_MIN_LOW_REG 0x08
30 #define AB8500_RTC_ALRM_MIN_MID_REG 0x09
31 #define AB8500_RTC_ALRM_MIN_HI_REG 0x0A
32 #define AB8500_RTC_STAT_REG 0x0B
33 #define AB8500_RTC_BKUP_CHG_REG 0x0C
34 #define AB8500_RTC_FORCE_BKUP_REG 0x0D
35 #define AB8500_RTC_CALIB_REG 0x0E
36 #define AB8500_RTC_SWITCH_STAT_REG 0x0F
38 /* RtcReadRequest bits */
39 #define RTC_READ_REQUEST 0x01
40 #define RTC_WRITE_REQUEST 0x02
43 #define RTC_ALARM_ENA 0x04
44 #define RTC_STATUS_DATA 0x01
46 #define COUNTS_PER_SEC (0xF000 / 60)
47 #define AB8500_RTC_EPOCH 2000
49 static const u8 ab8500_rtc_time_regs[] = {
50 AB8500_RTC_WATCH_TMIN_HI_REG, AB8500_RTC_WATCH_TMIN_MID_REG,
51 AB8500_RTC_WATCH_TMIN_LOW_REG, AB8500_RTC_WATCH_TSECHI_REG,
52 AB8500_RTC_WATCH_TSECMID_REG
55 static const u8 ab8500_rtc_alarm_regs[] = {
56 AB8500_RTC_ALRM_MIN_HI_REG, AB8500_RTC_ALRM_MIN_MID_REG,
57 AB8500_RTC_ALRM_MIN_LOW_REG
60 /* Calculate the seconds from 1970 to 01-01-2000 00:00:00 */
61 static unsigned long get_elapsed_seconds(int year)
64 struct rtc_time tm = {
65 .tm_year = year - 1900,
70 * This function calculates secs from 1970 and not from
71 * 1900, even if we supply the offset from year 1900.
73 rtc_tm_to_time(&tm, &secs);
77 static int ab8500_rtc_read_time(struct device *dev, struct rtc_time *tm)
79 unsigned long timeout = jiffies + HZ;
81 unsigned long mins, secs;
82 unsigned char buf[ARRAY_SIZE(ab8500_rtc_time_regs)];
85 /* Request a data read */
86 retval = abx500_set_register_interruptible(dev,
87 AB8500_RTC, AB8500_RTC_READ_REQ_REG, RTC_READ_REQUEST);
91 /* Early AB8500 chips will not clear the rtc read request bit */
92 if (abx500_get_chip_id(dev) == 0) {
93 usleep_range(1000, 1000);
95 /* Wait for some cycles after enabling the rtc read in ab8500 */
96 while (time_before(jiffies, timeout)) {
97 retval = abx500_get_register_interruptible(dev,
98 AB8500_RTC, AB8500_RTC_READ_REQ_REG, &value);
102 if (!(value & RTC_READ_REQUEST))
105 usleep_range(1000, 5000);
109 /* Read the Watchtime registers */
110 for (i = 0; i < ARRAY_SIZE(ab8500_rtc_time_regs); i++) {
111 retval = abx500_get_register_interruptible(dev,
112 AB8500_RTC, ab8500_rtc_time_regs[i], &value);
118 mins = (buf[0] << 16) | (buf[1] << 8) | buf[2];
120 secs = (buf[3] << 8) | buf[4];
121 secs = secs / COUNTS_PER_SEC;
122 secs = secs + (mins * 60);
124 /* Add back the initially subtracted number of seconds */
125 secs += get_elapsed_seconds(AB8500_RTC_EPOCH);
127 rtc_time_to_tm(secs, tm);
128 return rtc_valid_tm(tm);
131 static int ab8500_rtc_set_time(struct device *dev, struct rtc_time *tm)
134 unsigned char buf[ARRAY_SIZE(ab8500_rtc_time_regs)];
135 unsigned long no_secs, no_mins, secs = 0;
137 if (tm->tm_year < (AB8500_RTC_EPOCH - 1900)) {
138 dev_dbg(dev, "year should be equal to or greater than %d\n",
143 /* Get the number of seconds since 1970 */
144 rtc_tm_to_time(tm, &secs);
147 * Convert it to the number of seconds since 01-01-2000 00:00:00, since
148 * we only have a small counter in the RTC.
150 secs -= get_elapsed_seconds(AB8500_RTC_EPOCH);
155 /* Make the seconds count as per the RTC resolution */
156 no_secs = no_secs * COUNTS_PER_SEC;
158 buf[4] = no_secs & 0xFF;
159 buf[3] = (no_secs >> 8) & 0xFF;
161 buf[2] = no_mins & 0xFF;
162 buf[1] = (no_mins >> 8) & 0xFF;
163 buf[0] = (no_mins >> 16) & 0xFF;
165 for (i = 0; i < ARRAY_SIZE(ab8500_rtc_time_regs); i++) {
166 retval = abx500_set_register_interruptible(dev, AB8500_RTC,
167 ab8500_rtc_time_regs[i], buf[i]);
172 /* Request a data write */
173 return abx500_set_register_interruptible(dev, AB8500_RTC,
174 AB8500_RTC_READ_REQ_REG, RTC_WRITE_REQUEST);
177 static int ab8500_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
181 unsigned char buf[ARRAY_SIZE(ab8500_rtc_alarm_regs)];
182 unsigned long secs, mins;
184 /* Check if the alarm is enabled or not */
185 retval = abx500_get_register_interruptible(dev, AB8500_RTC,
186 AB8500_RTC_STAT_REG, &rtc_ctrl);
190 if (rtc_ctrl & RTC_ALARM_ENA)
197 for (i = 0; i < ARRAY_SIZE(ab8500_rtc_alarm_regs); i++) {
198 retval = abx500_get_register_interruptible(dev, AB8500_RTC,
199 ab8500_rtc_alarm_regs[i], &value);
205 mins = (buf[0] << 16) | (buf[1] << 8) | (buf[2]);
208 /* Add back the initially subtracted number of seconds */
209 secs += get_elapsed_seconds(AB8500_RTC_EPOCH);
211 rtc_time_to_tm(secs, &alarm->time);
213 return rtc_valid_tm(&alarm->time);
216 static int ab8500_rtc_irq_enable(struct device *dev, unsigned int enabled)
218 return abx500_mask_and_set_register_interruptible(dev, AB8500_RTC,
219 AB8500_RTC_STAT_REG, RTC_ALARM_ENA,
220 enabled ? RTC_ALARM_ENA : 0);
223 static int ab8500_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
226 unsigned char buf[ARRAY_SIZE(ab8500_rtc_alarm_regs)];
227 unsigned long mins, secs = 0;
229 if (alarm->time.tm_year < (AB8500_RTC_EPOCH - 1900)) {
230 dev_dbg(dev, "year should be equal to or greater than %d\n",
235 /* Get the number of seconds since 1970 */
236 rtc_tm_to_time(&alarm->time, &secs);
239 * Convert it to the number of seconds since 01-01-2000 00:00:00, since
240 * we only have a small counter in the RTC.
242 secs -= get_elapsed_seconds(AB8500_RTC_EPOCH);
246 buf[2] = mins & 0xFF;
247 buf[1] = (mins >> 8) & 0xFF;
248 buf[0] = (mins >> 16) & 0xFF;
250 /* Set the alarm time */
251 for (i = 0; i < ARRAY_SIZE(ab8500_rtc_alarm_regs); i++) {
252 retval = abx500_set_register_interruptible(dev, AB8500_RTC,
253 ab8500_rtc_alarm_regs[i], buf[i]);
258 return ab8500_rtc_irq_enable(dev, alarm->enabled);
262 static int ab8500_rtc_set_calibration(struct device *dev, int calibration)
268 * Check that the calibration value (which is in units of 0.5
269 * parts-per-million) is in the AB8500's range for RtcCalibration
270 * register. -128 (0x80) is not permitted because the AB8500 uses
271 * a sign-bit rather than two's complement, so 0x80 is just another
272 * representation of zero.
274 if ((calibration < -127) || (calibration > 127)) {
275 dev_err(dev, "RtcCalibration value outside permitted range\n");
280 * The AB8500 uses sign (in bit7) and magnitude (in bits0-7)
281 * so need to convert to this sort of representation before writing
282 * into RtcCalibration register...
284 if (calibration >= 0)
285 rtccal = 0x7F & calibration;
287 rtccal = ~(calibration - 1) | 0x80;
289 retval = abx500_set_register_interruptible(dev, AB8500_RTC,
290 AB8500_RTC_CALIB_REG, rtccal);
295 static int ab8500_rtc_get_calibration(struct device *dev, int *calibration)
300 retval = abx500_get_register_interruptible(dev, AB8500_RTC,
301 AB8500_RTC_CALIB_REG, &rtccal);
304 * The AB8500 uses sign (in bit7) and magnitude (in bits0-7)
305 * so need to convert value from RtcCalibration register into
306 * a two's complement signed value...
309 *calibration = 0 - (rtccal & 0x7F);
311 *calibration = 0x7F & rtccal;
317 static ssize_t ab8500_sysfs_store_rtc_calibration(struct device *dev,
318 struct device_attribute *attr,
319 const char *buf, size_t count)
324 if (sscanf(buf, " %i ", &calibration) != 1) {
325 dev_err(dev, "Failed to store RTC calibration attribute\n");
329 retval = ab8500_rtc_set_calibration(dev, calibration);
331 return retval ? retval : count;
334 static ssize_t ab8500_sysfs_show_rtc_calibration(struct device *dev,
335 struct device_attribute *attr, char *buf)
340 retval = ab8500_rtc_get_calibration(dev, &calibration);
342 dev_err(dev, "Failed to read RTC calibration attribute\n");
347 return sprintf(buf, "%d\n", calibration);
350 static DEVICE_ATTR(rtc_calibration, S_IRUGO | S_IWUSR,
351 ab8500_sysfs_show_rtc_calibration,
352 ab8500_sysfs_store_rtc_calibration);
354 static int ab8500_sysfs_rtc_register(struct device *dev)
356 return device_create_file(dev, &dev_attr_rtc_calibration);
359 static void ab8500_sysfs_rtc_unregister(struct device *dev)
361 device_remove_file(dev, &dev_attr_rtc_calibration);
364 static irqreturn_t rtc_alarm_handler(int irq, void *data)
366 struct rtc_device *rtc = data;
367 unsigned long events = RTC_IRQF | RTC_AF;
369 dev_dbg(&rtc->dev, "%s\n", __func__);
370 rtc_update_irq(rtc, 1, events);
375 static const struct rtc_class_ops ab8500_rtc_ops = {
376 .read_time = ab8500_rtc_read_time,
377 .set_time = ab8500_rtc_set_time,
378 .read_alarm = ab8500_rtc_read_alarm,
379 .set_alarm = ab8500_rtc_set_alarm,
380 .alarm_irq_enable = ab8500_rtc_irq_enable,
383 static int __devinit ab8500_rtc_probe(struct platform_device *pdev)
386 struct rtc_device *rtc;
390 irq = platform_get_irq_byname(pdev, "ALARM");
394 /* For RTC supply test */
395 err = abx500_mask_and_set_register_interruptible(&pdev->dev, AB8500_RTC,
396 AB8500_RTC_STAT_REG, RTC_STATUS_DATA, RTC_STATUS_DATA);
400 /* Wait for reset by the PorRtc */
401 usleep_range(1000, 5000);
403 err = abx500_get_register_interruptible(&pdev->dev, AB8500_RTC,
404 AB8500_RTC_STAT_REG, &rtc_ctrl);
408 /* Check if the RTC Supply fails */
409 if (!(rtc_ctrl & RTC_STATUS_DATA)) {
410 dev_err(&pdev->dev, "RTC supply failure\n");
414 device_init_wakeup(&pdev->dev, true);
416 rtc = rtc_device_register("ab8500-rtc", &pdev->dev, &ab8500_rtc_ops,
419 dev_err(&pdev->dev, "Registration failed\n");
424 err = request_threaded_irq(irq, NULL, rtc_alarm_handler,
425 IRQF_NO_SUSPEND, "ab8500-rtc", rtc);
427 rtc_device_unregister(rtc);
431 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 struct platform_driver ab8500_rtc_driver = {
459 .name = "ab8500-rtc",
460 .owner = THIS_MODULE,
462 .probe = ab8500_rtc_probe,
463 .remove = __devexit_p(ab8500_rtc_remove),
466 module_platform_driver(ab8500_rtc_driver);
468 MODULE_AUTHOR("Virupax Sadashivpetimath <virupax.sadashivpetimath@stericsson.com>");
469 MODULE_DESCRIPTION("AB8500 RTC Driver");
470 MODULE_LICENSE("GPL v2");