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0af62f4d VS |
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> | |
47c16975 | 17 | #include <linux/mfd/abx500.h> |
ee66e653 | 18 | #include <linux/mfd/abx500/ab8500.h> |
0af62f4d | 19 | #include <linux/delay.h> |
ad49fcbe | 20 | #include <linux/of.h> |
0af62f4d | 21 | |
47c16975 MW |
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 | |
0af62f4d VS |
38 | |
39 | /* RtcReadRequest bits */ | |
40 | #define RTC_READ_REQUEST 0x01 | |
41 | #define RTC_WRITE_REQUEST 0x02 | |
42 | ||
43 | /* RtcCtrl bits */ | |
44 | #define RTC_ALARM_ENA 0x04 | |
45 | #define RTC_STATUS_DATA 0x01 | |
46 | ||
47 | #define COUNTS_PER_SEC (0xF000 / 60) | |
48 | #define AB8500_RTC_EPOCH 2000 | |
49 | ||
47c16975 | 50 | static const u8 ab8500_rtc_time_regs[] = { |
0af62f4d VS |
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 | |
54 | }; | |
55 | ||
47c16975 | 56 | static const u8 ab8500_rtc_alarm_regs[] = { |
0af62f4d VS |
57 | AB8500_RTC_ALRM_MIN_HI_REG, AB8500_RTC_ALRM_MIN_MID_REG, |
58 | AB8500_RTC_ALRM_MIN_LOW_REG | |
59 | }; | |
60 | ||
61 | /* Calculate the seconds from 1970 to 01-01-2000 00:00:00 */ | |
62 | static unsigned long get_elapsed_seconds(int year) | |
63 | { | |
64 | unsigned long secs; | |
65 | struct rtc_time tm = { | |
66 | .tm_year = year - 1900, | |
67 | .tm_mday = 1, | |
68 | }; | |
69 | ||
70 | /* | |
71 | * This function calculates secs from 1970 and not from | |
72 | * 1900, even if we supply the offset from year 1900. | |
73 | */ | |
74 | rtc_tm_to_time(&tm, &secs); | |
75 | return secs; | |
76 | } | |
77 | ||
78 | static int ab8500_rtc_read_time(struct device *dev, struct rtc_time *tm) | |
79 | { | |
0af62f4d VS |
80 | unsigned long timeout = jiffies + HZ; |
81 | int retval, i; | |
82 | unsigned long mins, secs; | |
83 | unsigned char buf[ARRAY_SIZE(ab8500_rtc_time_regs)]; | |
47c16975 | 84 | u8 value; |
0af62f4d VS |
85 | |
86 | /* Request a data read */ | |
47c16975 MW |
87 | retval = abx500_set_register_interruptible(dev, |
88 | AB8500_RTC, AB8500_RTC_READ_REQ_REG, RTC_READ_REQUEST); | |
0af62f4d VS |
89 | if (retval < 0) |
90 | return retval; | |
91 | ||
92 | /* Early AB8500 chips will not clear the rtc read request bit */ | |
47c16975 | 93 | if (abx500_get_chip_id(dev) == 0) { |
012e52e1 | 94 | usleep_range(1000, 1000); |
0af62f4d VS |
95 | } else { |
96 | /* Wait for some cycles after enabling the rtc read in ab8500 */ | |
97 | while (time_before(jiffies, timeout)) { | |
47c16975 MW |
98 | retval = abx500_get_register_interruptible(dev, |
99 | AB8500_RTC, AB8500_RTC_READ_REQ_REG, &value); | |
0af62f4d VS |
100 | if (retval < 0) |
101 | return retval; | |
102 | ||
47c16975 | 103 | if (!(value & RTC_READ_REQUEST)) |
0af62f4d VS |
104 | break; |
105 | ||
012e52e1 | 106 | usleep_range(1000, 5000); |
0af62f4d VS |
107 | } |
108 | } | |
109 | ||
110 | /* Read the Watchtime registers */ | |
111 | for (i = 0; i < ARRAY_SIZE(ab8500_rtc_time_regs); i++) { | |
47c16975 MW |
112 | retval = abx500_get_register_interruptible(dev, |
113 | AB8500_RTC, ab8500_rtc_time_regs[i], &value); | |
0af62f4d VS |
114 | if (retval < 0) |
115 | return retval; | |
47c16975 | 116 | buf[i] = value; |
0af62f4d VS |
117 | } |
118 | ||
119 | mins = (buf[0] << 16) | (buf[1] << 8) | buf[2]; | |
120 | ||
121 | secs = (buf[3] << 8) | buf[4]; | |
122 | secs = secs / COUNTS_PER_SEC; | |
123 | secs = secs + (mins * 60); | |
124 | ||
125 | /* Add back the initially subtracted number of seconds */ | |
126 | secs += get_elapsed_seconds(AB8500_RTC_EPOCH); | |
127 | ||
128 | rtc_time_to_tm(secs, tm); | |
129 | return rtc_valid_tm(tm); | |
130 | } | |
131 | ||
132 | static int ab8500_rtc_set_time(struct device *dev, struct rtc_time *tm) | |
133 | { | |
0af62f4d VS |
134 | int retval, i; |
135 | unsigned char buf[ARRAY_SIZE(ab8500_rtc_time_regs)]; | |
136 | unsigned long no_secs, no_mins, secs = 0; | |
137 | ||
138 | if (tm->tm_year < (AB8500_RTC_EPOCH - 1900)) { | |
139 | dev_dbg(dev, "year should be equal to or greater than %d\n", | |
140 | AB8500_RTC_EPOCH); | |
141 | return -EINVAL; | |
142 | } | |
143 | ||
144 | /* Get the number of seconds since 1970 */ | |
145 | rtc_tm_to_time(tm, &secs); | |
146 | ||
147 | /* | |
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. | |
150 | */ | |
151 | secs -= get_elapsed_seconds(AB8500_RTC_EPOCH); | |
152 | ||
153 | no_mins = secs / 60; | |
154 | ||
155 | no_secs = secs % 60; | |
156 | /* Make the seconds count as per the RTC resolution */ | |
157 | no_secs = no_secs * COUNTS_PER_SEC; | |
158 | ||
159 | buf[4] = no_secs & 0xFF; | |
160 | buf[3] = (no_secs >> 8) & 0xFF; | |
161 | ||
162 | buf[2] = no_mins & 0xFF; | |
163 | buf[1] = (no_mins >> 8) & 0xFF; | |
164 | buf[0] = (no_mins >> 16) & 0xFF; | |
165 | ||
166 | for (i = 0; i < ARRAY_SIZE(ab8500_rtc_time_regs); i++) { | |
47c16975 MW |
167 | retval = abx500_set_register_interruptible(dev, AB8500_RTC, |
168 | ab8500_rtc_time_regs[i], buf[i]); | |
0af62f4d VS |
169 | if (retval < 0) |
170 | return retval; | |
171 | } | |
172 | ||
173 | /* Request a data write */ | |
47c16975 MW |
174 | return abx500_set_register_interruptible(dev, AB8500_RTC, |
175 | AB8500_RTC_READ_REQ_REG, RTC_WRITE_REQUEST); | |
0af62f4d VS |
176 | } |
177 | ||
178 | static int ab8500_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm) | |
179 | { | |
0af62f4d | 180 | int retval, i; |
47c16975 | 181 | u8 rtc_ctrl, value; |
0af62f4d VS |
182 | unsigned char buf[ARRAY_SIZE(ab8500_rtc_alarm_regs)]; |
183 | unsigned long secs, mins; | |
184 | ||
185 | /* Check if the alarm is enabled or not */ | |
47c16975 MW |
186 | retval = abx500_get_register_interruptible(dev, AB8500_RTC, |
187 | AB8500_RTC_STAT_REG, &rtc_ctrl); | |
188 | if (retval < 0) | |
189 | return retval; | |
0af62f4d VS |
190 | |
191 | if (rtc_ctrl & RTC_ALARM_ENA) | |
192 | alarm->enabled = 1; | |
193 | else | |
194 | alarm->enabled = 0; | |
195 | ||
196 | alarm->pending = 0; | |
197 | ||
198 | for (i = 0; i < ARRAY_SIZE(ab8500_rtc_alarm_regs); i++) { | |
47c16975 MW |
199 | retval = abx500_get_register_interruptible(dev, AB8500_RTC, |
200 | ab8500_rtc_alarm_regs[i], &value); | |
0af62f4d VS |
201 | if (retval < 0) |
202 | return retval; | |
47c16975 | 203 | buf[i] = value; |
0af62f4d VS |
204 | } |
205 | ||
206 | mins = (buf[0] << 16) | (buf[1] << 8) | (buf[2]); | |
207 | secs = mins * 60; | |
208 | ||
209 | /* Add back the initially subtracted number of seconds */ | |
210 | secs += get_elapsed_seconds(AB8500_RTC_EPOCH); | |
211 | ||
212 | rtc_time_to_tm(secs, &alarm->time); | |
213 | ||
214 | return rtc_valid_tm(&alarm->time); | |
215 | } | |
216 | ||
217 | static int ab8500_rtc_irq_enable(struct device *dev, unsigned int enabled) | |
218 | { | |
47c16975 MW |
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); | |
0af62f4d VS |
222 | } |
223 | ||
224 | static int ab8500_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm) | |
225 | { | |
0af62f4d VS |
226 | int retval, i; |
227 | unsigned char buf[ARRAY_SIZE(ab8500_rtc_alarm_regs)]; | |
228 | unsigned long mins, secs = 0; | |
229 | ||
230 | if (alarm->time.tm_year < (AB8500_RTC_EPOCH - 1900)) { | |
231 | dev_dbg(dev, "year should be equal to or greater than %d\n", | |
232 | AB8500_RTC_EPOCH); | |
233 | return -EINVAL; | |
234 | } | |
235 | ||
236 | /* Get the number of seconds since 1970 */ | |
237 | rtc_tm_to_time(&alarm->time, &secs); | |
238 | ||
239 | /* | |
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. | |
242 | */ | |
243 | secs -= get_elapsed_seconds(AB8500_RTC_EPOCH); | |
244 | ||
245 | mins = secs / 60; | |
246 | ||
247 | buf[2] = mins & 0xFF; | |
248 | buf[1] = (mins >> 8) & 0xFF; | |
249 | buf[0] = (mins >> 16) & 0xFF; | |
250 | ||
251 | /* Set the alarm time */ | |
252 | for (i = 0; i < ARRAY_SIZE(ab8500_rtc_alarm_regs); i++) { | |
47c16975 MW |
253 | retval = abx500_set_register_interruptible(dev, AB8500_RTC, |
254 | ab8500_rtc_alarm_regs[i], buf[i]); | |
0af62f4d VS |
255 | if (retval < 0) |
256 | return retval; | |
257 | } | |
258 | ||
259 | return ab8500_rtc_irq_enable(dev, alarm->enabled); | |
260 | } | |
261 | ||
dda367ac MG |
262 | |
263 | static int ab8500_rtc_set_calibration(struct device *dev, int calibration) | |
264 | { | |
265 | int retval; | |
266 | u8 rtccal = 0; | |
267 | ||
268 | /* | |
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. | |
274 | */ | |
275 | if ((calibration < -127) || (calibration > 127)) { | |
276 | dev_err(dev, "RtcCalibration value outside permitted range\n"); | |
277 | return -EINVAL; | |
278 | } | |
279 | ||
280 | /* | |
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... | |
284 | */ | |
285 | if (calibration >= 0) | |
286 | rtccal = 0x7F & calibration; | |
287 | else | |
288 | rtccal = ~(calibration - 1) | 0x80; | |
289 | ||
290 | retval = abx500_set_register_interruptible(dev, AB8500_RTC, | |
291 | AB8500_RTC_CALIB_REG, rtccal); | |
292 | ||
293 | return retval; | |
294 | } | |
295 | ||
296 | static int ab8500_rtc_get_calibration(struct device *dev, int *calibration) | |
297 | { | |
298 | int retval; | |
299 | u8 rtccal = 0; | |
300 | ||
301 | retval = abx500_get_register_interruptible(dev, AB8500_RTC, | |
302 | AB8500_RTC_CALIB_REG, &rtccal); | |
303 | if (retval >= 0) { | |
304 | /* | |
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... | |
308 | */ | |
309 | if (rtccal & 0x80) | |
310 | *calibration = 0 - (rtccal & 0x7F); | |
311 | else | |
312 | *calibration = 0x7F & rtccal; | |
313 | } | |
314 | ||
315 | return retval; | |
316 | } | |
317 | ||
318 | static ssize_t ab8500_sysfs_store_rtc_calibration(struct device *dev, | |
319 | struct device_attribute *attr, | |
320 | const char *buf, size_t count) | |
321 | { | |
322 | int retval; | |
323 | int calibration = 0; | |
324 | ||
325 | if (sscanf(buf, " %i ", &calibration) != 1) { | |
326 | dev_err(dev, "Failed to store RTC calibration attribute\n"); | |
327 | return -EINVAL; | |
328 | } | |
329 | ||
330 | retval = ab8500_rtc_set_calibration(dev, calibration); | |
331 | ||
332 | return retval ? retval : count; | |
333 | } | |
334 | ||
335 | static ssize_t ab8500_sysfs_show_rtc_calibration(struct device *dev, | |
336 | struct device_attribute *attr, char *buf) | |
337 | { | |
338 | int retval = 0; | |
339 | int calibration = 0; | |
340 | ||
341 | retval = ab8500_rtc_get_calibration(dev, &calibration); | |
342 | if (retval < 0) { | |
343 | dev_err(dev, "Failed to read RTC calibration attribute\n"); | |
344 | sprintf(buf, "0\n"); | |
345 | return retval; | |
346 | } | |
347 | ||
348 | return sprintf(buf, "%d\n", calibration); | |
349 | } | |
350 | ||
351 | static DEVICE_ATTR(rtc_calibration, S_IRUGO | S_IWUSR, | |
352 | ab8500_sysfs_show_rtc_calibration, | |
353 | ab8500_sysfs_store_rtc_calibration); | |
354 | ||
355 | static int ab8500_sysfs_rtc_register(struct device *dev) | |
356 | { | |
357 | return device_create_file(dev, &dev_attr_rtc_calibration); | |
358 | } | |
359 | ||
360 | static void ab8500_sysfs_rtc_unregister(struct device *dev) | |
361 | { | |
362 | device_remove_file(dev, &dev_attr_rtc_calibration); | |
363 | } | |
364 | ||
0af62f4d VS |
365 | static irqreturn_t rtc_alarm_handler(int irq, void *data) |
366 | { | |
367 | struct rtc_device *rtc = data; | |
368 | unsigned long events = RTC_IRQF | RTC_AF; | |
369 | ||
370 | dev_dbg(&rtc->dev, "%s\n", __func__); | |
371 | rtc_update_irq(rtc, 1, events); | |
372 | ||
373 | return IRQ_HANDLED; | |
374 | } | |
375 | ||
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, | |
382 | }; | |
383 | ||
384 | static int __devinit ab8500_rtc_probe(struct platform_device *pdev) | |
385 | { | |
0af62f4d VS |
386 | int err; |
387 | struct rtc_device *rtc; | |
47c16975 | 388 | u8 rtc_ctrl; |
0af62f4d VS |
389 | int irq; |
390 | ||
391 | irq = platform_get_irq_byname(pdev, "ALARM"); | |
392 | if (irq < 0) | |
393 | return irq; | |
394 | ||
395 | /* For RTC supply test */ | |
47c16975 MW |
396 | err = abx500_mask_and_set_register_interruptible(&pdev->dev, AB8500_RTC, |
397 | AB8500_RTC_STAT_REG, RTC_STATUS_DATA, RTC_STATUS_DATA); | |
0af62f4d VS |
398 | if (err < 0) |
399 | return err; | |
400 | ||
401 | /* Wait for reset by the PorRtc */ | |
012e52e1 | 402 | usleep_range(1000, 5000); |
0af62f4d | 403 | |
47c16975 MW |
404 | err = abx500_get_register_interruptible(&pdev->dev, AB8500_RTC, |
405 | AB8500_RTC_STAT_REG, &rtc_ctrl); | |
406 | if (err < 0) | |
407 | return err; | |
0af62f4d VS |
408 | |
409 | /* Check if the RTC Supply fails */ | |
410 | if (!(rtc_ctrl & RTC_STATUS_DATA)) { | |
411 | dev_err(&pdev->dev, "RTC supply failure\n"); | |
412 | return -ENODEV; | |
413 | } | |
414 | ||
b62581e6 AL |
415 | device_init_wakeup(&pdev->dev, true); |
416 | ||
0af62f4d VS |
417 | rtc = rtc_device_register("ab8500-rtc", &pdev->dev, &ab8500_rtc_ops, |
418 | THIS_MODULE); | |
419 | if (IS_ERR(rtc)) { | |
420 | dev_err(&pdev->dev, "Registration failed\n"); | |
421 | err = PTR_ERR(rtc); | |
422 | return err; | |
423 | } | |
424 | ||
10d065e6 | 425 | err = request_threaded_irq(irq, NULL, rtc_alarm_handler, |
3cfd16a5 | 426 | IRQF_NO_SUSPEND | IRQF_ONESHOT, "ab8500-rtc", rtc); |
0af62f4d VS |
427 | if (err < 0) { |
428 | rtc_device_unregister(rtc); | |
429 | return err; | |
430 | } | |
431 | ||
432 | platform_set_drvdata(pdev, rtc); | |
433 | ||
dda367ac MG |
434 | err = ab8500_sysfs_rtc_register(&pdev->dev); |
435 | if (err) { | |
436 | dev_err(&pdev->dev, "sysfs RTC failed to register\n"); | |
437 | return err; | |
438 | } | |
439 | ||
0af62f4d VS |
440 | return 0; |
441 | } | |
442 | ||
443 | static int __devexit ab8500_rtc_remove(struct platform_device *pdev) | |
444 | { | |
445 | struct rtc_device *rtc = platform_get_drvdata(pdev); | |
446 | int irq = platform_get_irq_byname(pdev, "ALARM"); | |
447 | ||
dda367ac MG |
448 | ab8500_sysfs_rtc_unregister(&pdev->dev); |
449 | ||
0af62f4d VS |
450 | free_irq(irq, rtc); |
451 | rtc_device_unregister(rtc); | |
452 | platform_set_drvdata(pdev, NULL); | |
453 | ||
454 | return 0; | |
455 | } | |
456 | ||
ad49fcbe LJ |
457 | static const struct of_device_id ab8500_rtc_match[] = { |
458 | { .compatible = "stericsson,ab8500-rtc", }, | |
459 | {} | |
460 | }; | |
461 | ||
0af62f4d VS |
462 | static struct platform_driver ab8500_rtc_driver = { |
463 | .driver = { | |
464 | .name = "ab8500-rtc", | |
465 | .owner = THIS_MODULE, | |
ad49fcbe | 466 | .of_match_table = ab8500_rtc_match, |
0af62f4d VS |
467 | }, |
468 | .probe = ab8500_rtc_probe, | |
469 | .remove = __devexit_p(ab8500_rtc_remove), | |
470 | }; | |
471 | ||
0c4eae66 | 472 | module_platform_driver(ab8500_rtc_driver); |
0af62f4d | 473 | |
0af62f4d VS |
474 | MODULE_AUTHOR("Virupax Sadashivpetimath <virupax.sadashivpetimath@stericsson.com>"); |
475 | MODULE_DESCRIPTION("AB8500 RTC Driver"); | |
476 | MODULE_LICENSE("GPL v2"); |