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");