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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> |
0af62f4d VS |
18 | #include <linux/mfd/ab8500.h> |
19 | #include <linux/delay.h> | |
20 | ||
47c16975 MW |
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 | |
0af62f4d VS |
37 | |
38 | /* RtcReadRequest bits */ | |
39 | #define RTC_READ_REQUEST 0x01 | |
40 | #define RTC_WRITE_REQUEST 0x02 | |
41 | ||
42 | /* RtcCtrl bits */ | |
43 | #define RTC_ALARM_ENA 0x04 | |
44 | #define RTC_STATUS_DATA 0x01 | |
45 | ||
46 | #define COUNTS_PER_SEC (0xF000 / 60) | |
47 | #define AB8500_RTC_EPOCH 2000 | |
48 | ||
47c16975 | 49 | static const u8 ab8500_rtc_time_regs[] = { |
0af62f4d VS |
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 | |
53 | }; | |
54 | ||
47c16975 | 55 | static const u8 ab8500_rtc_alarm_regs[] = { |
0af62f4d VS |
56 | AB8500_RTC_ALRM_MIN_HI_REG, AB8500_RTC_ALRM_MIN_MID_REG, |
57 | AB8500_RTC_ALRM_MIN_LOW_REG | |
58 | }; | |
59 | ||
60 | /* Calculate the seconds from 1970 to 01-01-2000 00:00:00 */ | |
61 | static unsigned long get_elapsed_seconds(int year) | |
62 | { | |
63 | unsigned long secs; | |
64 | struct rtc_time tm = { | |
65 | .tm_year = year - 1900, | |
66 | .tm_mday = 1, | |
67 | }; | |
68 | ||
69 | /* | |
70 | * This function calculates secs from 1970 and not from | |
71 | * 1900, even if we supply the offset from year 1900. | |
72 | */ | |
73 | rtc_tm_to_time(&tm, &secs); | |
74 | return secs; | |
75 | } | |
76 | ||
77 | static int ab8500_rtc_read_time(struct device *dev, struct rtc_time *tm) | |
78 | { | |
0af62f4d VS |
79 | unsigned long timeout = jiffies + HZ; |
80 | int retval, i; | |
81 | unsigned long mins, secs; | |
82 | unsigned char buf[ARRAY_SIZE(ab8500_rtc_time_regs)]; | |
47c16975 | 83 | u8 value; |
0af62f4d VS |
84 | |
85 | /* Request a data read */ | |
47c16975 MW |
86 | retval = abx500_set_register_interruptible(dev, |
87 | AB8500_RTC, AB8500_RTC_READ_REQ_REG, RTC_READ_REQUEST); | |
0af62f4d VS |
88 | if (retval < 0) |
89 | return retval; | |
90 | ||
91 | /* Early AB8500 chips will not clear the rtc read request bit */ | |
47c16975 | 92 | if (abx500_get_chip_id(dev) == 0) { |
012e52e1 | 93 | usleep_range(1000, 1000); |
0af62f4d VS |
94 | } else { |
95 | /* Wait for some cycles after enabling the rtc read in ab8500 */ | |
96 | while (time_before(jiffies, timeout)) { | |
47c16975 MW |
97 | retval = abx500_get_register_interruptible(dev, |
98 | AB8500_RTC, AB8500_RTC_READ_REQ_REG, &value); | |
0af62f4d VS |
99 | if (retval < 0) |
100 | return retval; | |
101 | ||
47c16975 | 102 | if (!(value & RTC_READ_REQUEST)) |
0af62f4d VS |
103 | break; |
104 | ||
012e52e1 | 105 | usleep_range(1000, 5000); |
0af62f4d VS |
106 | } |
107 | } | |
108 | ||
109 | /* Read the Watchtime registers */ | |
110 | for (i = 0; i < ARRAY_SIZE(ab8500_rtc_time_regs); i++) { | |
47c16975 MW |
111 | retval = abx500_get_register_interruptible(dev, |
112 | AB8500_RTC, ab8500_rtc_time_regs[i], &value); | |
0af62f4d VS |
113 | if (retval < 0) |
114 | return retval; | |
47c16975 | 115 | buf[i] = value; |
0af62f4d VS |
116 | } |
117 | ||
118 | mins = (buf[0] << 16) | (buf[1] << 8) | buf[2]; | |
119 | ||
120 | secs = (buf[3] << 8) | buf[4]; | |
121 | secs = secs / COUNTS_PER_SEC; | |
122 | secs = secs + (mins * 60); | |
123 | ||
124 | /* Add back the initially subtracted number of seconds */ | |
125 | secs += get_elapsed_seconds(AB8500_RTC_EPOCH); | |
126 | ||
127 | rtc_time_to_tm(secs, tm); | |
128 | return rtc_valid_tm(tm); | |
129 | } | |
130 | ||
131 | static int ab8500_rtc_set_time(struct device *dev, struct rtc_time *tm) | |
132 | { | |
0af62f4d VS |
133 | int retval, i; |
134 | unsigned char buf[ARRAY_SIZE(ab8500_rtc_time_regs)]; | |
135 | unsigned long no_secs, no_mins, secs = 0; | |
136 | ||
137 | if (tm->tm_year < (AB8500_RTC_EPOCH - 1900)) { | |
138 | dev_dbg(dev, "year should be equal to or greater than %d\n", | |
139 | AB8500_RTC_EPOCH); | |
140 | return -EINVAL; | |
141 | } | |
142 | ||
143 | /* Get the number of seconds since 1970 */ | |
144 | rtc_tm_to_time(tm, &secs); | |
145 | ||
146 | /* | |
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. | |
149 | */ | |
150 | secs -= get_elapsed_seconds(AB8500_RTC_EPOCH); | |
151 | ||
152 | no_mins = secs / 60; | |
153 | ||
154 | no_secs = secs % 60; | |
155 | /* Make the seconds count as per the RTC resolution */ | |
156 | no_secs = no_secs * COUNTS_PER_SEC; | |
157 | ||
158 | buf[4] = no_secs & 0xFF; | |
159 | buf[3] = (no_secs >> 8) & 0xFF; | |
160 | ||
161 | buf[2] = no_mins & 0xFF; | |
162 | buf[1] = (no_mins >> 8) & 0xFF; | |
163 | buf[0] = (no_mins >> 16) & 0xFF; | |
164 | ||
165 | for (i = 0; i < ARRAY_SIZE(ab8500_rtc_time_regs); i++) { | |
47c16975 MW |
166 | retval = abx500_set_register_interruptible(dev, AB8500_RTC, |
167 | ab8500_rtc_time_regs[i], buf[i]); | |
0af62f4d VS |
168 | if (retval < 0) |
169 | return retval; | |
170 | } | |
171 | ||
172 | /* Request a data write */ | |
47c16975 MW |
173 | return abx500_set_register_interruptible(dev, AB8500_RTC, |
174 | AB8500_RTC_READ_REQ_REG, RTC_WRITE_REQUEST); | |
0af62f4d VS |
175 | } |
176 | ||
177 | static int ab8500_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm) | |
178 | { | |
0af62f4d | 179 | int retval, i; |
47c16975 | 180 | u8 rtc_ctrl, value; |
0af62f4d VS |
181 | unsigned char buf[ARRAY_SIZE(ab8500_rtc_alarm_regs)]; |
182 | unsigned long secs, mins; | |
183 | ||
184 | /* Check if the alarm is enabled or not */ | |
47c16975 MW |
185 | retval = abx500_get_register_interruptible(dev, AB8500_RTC, |
186 | AB8500_RTC_STAT_REG, &rtc_ctrl); | |
187 | if (retval < 0) | |
188 | return retval; | |
0af62f4d VS |
189 | |
190 | if (rtc_ctrl & RTC_ALARM_ENA) | |
191 | alarm->enabled = 1; | |
192 | else | |
193 | alarm->enabled = 0; | |
194 | ||
195 | alarm->pending = 0; | |
196 | ||
197 | for (i = 0; i < ARRAY_SIZE(ab8500_rtc_alarm_regs); i++) { | |
47c16975 MW |
198 | retval = abx500_get_register_interruptible(dev, AB8500_RTC, |
199 | ab8500_rtc_alarm_regs[i], &value); | |
0af62f4d VS |
200 | if (retval < 0) |
201 | return retval; | |
47c16975 | 202 | buf[i] = value; |
0af62f4d VS |
203 | } |
204 | ||
205 | mins = (buf[0] << 16) | (buf[1] << 8) | (buf[2]); | |
206 | secs = mins * 60; | |
207 | ||
208 | /* Add back the initially subtracted number of seconds */ | |
209 | secs += get_elapsed_seconds(AB8500_RTC_EPOCH); | |
210 | ||
211 | rtc_time_to_tm(secs, &alarm->time); | |
212 | ||
213 | return rtc_valid_tm(&alarm->time); | |
214 | } | |
215 | ||
216 | static int ab8500_rtc_irq_enable(struct device *dev, unsigned int enabled) | |
217 | { | |
47c16975 MW |
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); | |
0af62f4d VS |
221 | } |
222 | ||
223 | static int ab8500_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm) | |
224 | { | |
0af62f4d VS |
225 | int retval, i; |
226 | unsigned char buf[ARRAY_SIZE(ab8500_rtc_alarm_regs)]; | |
227 | unsigned long mins, secs = 0; | |
228 | ||
229 | if (alarm->time.tm_year < (AB8500_RTC_EPOCH - 1900)) { | |
230 | dev_dbg(dev, "year should be equal to or greater than %d\n", | |
231 | AB8500_RTC_EPOCH); | |
232 | return -EINVAL; | |
233 | } | |
234 | ||
235 | /* Get the number of seconds since 1970 */ | |
236 | rtc_tm_to_time(&alarm->time, &secs); | |
237 | ||
238 | /* | |
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. | |
241 | */ | |
242 | secs -= get_elapsed_seconds(AB8500_RTC_EPOCH); | |
243 | ||
244 | mins = secs / 60; | |
245 | ||
246 | buf[2] = mins & 0xFF; | |
247 | buf[1] = (mins >> 8) & 0xFF; | |
248 | buf[0] = (mins >> 16) & 0xFF; | |
249 | ||
250 | /* Set the alarm time */ | |
251 | for (i = 0; i < ARRAY_SIZE(ab8500_rtc_alarm_regs); i++) { | |
47c16975 MW |
252 | retval = abx500_set_register_interruptible(dev, AB8500_RTC, |
253 | ab8500_rtc_alarm_regs[i], buf[i]); | |
0af62f4d VS |
254 | if (retval < 0) |
255 | return retval; | |
256 | } | |
257 | ||
258 | return ab8500_rtc_irq_enable(dev, alarm->enabled); | |
259 | } | |
260 | ||
dda367ac MG |
261 | |
262 | static int ab8500_rtc_set_calibration(struct device *dev, int calibration) | |
263 | { | |
264 | int retval; | |
265 | u8 rtccal = 0; | |
266 | ||
267 | /* | |
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. | |
273 | */ | |
274 | if ((calibration < -127) || (calibration > 127)) { | |
275 | dev_err(dev, "RtcCalibration value outside permitted range\n"); | |
276 | return -EINVAL; | |
277 | } | |
278 | ||
279 | /* | |
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... | |
283 | */ | |
284 | if (calibration >= 0) | |
285 | rtccal = 0x7F & calibration; | |
286 | else | |
287 | rtccal = ~(calibration - 1) | 0x80; | |
288 | ||
289 | retval = abx500_set_register_interruptible(dev, AB8500_RTC, | |
290 | AB8500_RTC_CALIB_REG, rtccal); | |
291 | ||
292 | return retval; | |
293 | } | |
294 | ||
295 | static int ab8500_rtc_get_calibration(struct device *dev, int *calibration) | |
296 | { | |
297 | int retval; | |
298 | u8 rtccal = 0; | |
299 | ||
300 | retval = abx500_get_register_interruptible(dev, AB8500_RTC, | |
301 | AB8500_RTC_CALIB_REG, &rtccal); | |
302 | if (retval >= 0) { | |
303 | /* | |
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... | |
307 | */ | |
308 | if (rtccal & 0x80) | |
309 | *calibration = 0 - (rtccal & 0x7F); | |
310 | else | |
311 | *calibration = 0x7F & rtccal; | |
312 | } | |
313 | ||
314 | return retval; | |
315 | } | |
316 | ||
317 | static ssize_t ab8500_sysfs_store_rtc_calibration(struct device *dev, | |
318 | struct device_attribute *attr, | |
319 | const char *buf, size_t count) | |
320 | { | |
321 | int retval; | |
322 | int calibration = 0; | |
323 | ||
324 | if (sscanf(buf, " %i ", &calibration) != 1) { | |
325 | dev_err(dev, "Failed to store RTC calibration attribute\n"); | |
326 | return -EINVAL; | |
327 | } | |
328 | ||
329 | retval = ab8500_rtc_set_calibration(dev, calibration); | |
330 | ||
331 | return retval ? retval : count; | |
332 | } | |
333 | ||
334 | static ssize_t ab8500_sysfs_show_rtc_calibration(struct device *dev, | |
335 | struct device_attribute *attr, char *buf) | |
336 | { | |
337 | int retval = 0; | |
338 | int calibration = 0; | |
339 | ||
340 | retval = ab8500_rtc_get_calibration(dev, &calibration); | |
341 | if (retval < 0) { | |
342 | dev_err(dev, "Failed to read RTC calibration attribute\n"); | |
343 | sprintf(buf, "0\n"); | |
344 | return retval; | |
345 | } | |
346 | ||
347 | return sprintf(buf, "%d\n", calibration); | |
348 | } | |
349 | ||
350 | static DEVICE_ATTR(rtc_calibration, S_IRUGO | S_IWUSR, | |
351 | ab8500_sysfs_show_rtc_calibration, | |
352 | ab8500_sysfs_store_rtc_calibration); | |
353 | ||
354 | static int ab8500_sysfs_rtc_register(struct device *dev) | |
355 | { | |
356 | return device_create_file(dev, &dev_attr_rtc_calibration); | |
357 | } | |
358 | ||
359 | static void ab8500_sysfs_rtc_unregister(struct device *dev) | |
360 | { | |
361 | device_remove_file(dev, &dev_attr_rtc_calibration); | |
362 | } | |
363 | ||
0af62f4d VS |
364 | static irqreturn_t rtc_alarm_handler(int irq, void *data) |
365 | { | |
366 | struct rtc_device *rtc = data; | |
367 | unsigned long events = RTC_IRQF | RTC_AF; | |
368 | ||
369 | dev_dbg(&rtc->dev, "%s\n", __func__); | |
370 | rtc_update_irq(rtc, 1, events); | |
371 | ||
372 | return IRQ_HANDLED; | |
373 | } | |
374 | ||
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, | |
381 | }; | |
382 | ||
383 | static int __devinit ab8500_rtc_probe(struct platform_device *pdev) | |
384 | { | |
0af62f4d VS |
385 | int err; |
386 | struct rtc_device *rtc; | |
47c16975 | 387 | u8 rtc_ctrl; |
0af62f4d VS |
388 | int irq; |
389 | ||
390 | irq = platform_get_irq_byname(pdev, "ALARM"); | |
391 | if (irq < 0) | |
392 | return irq; | |
393 | ||
394 | /* For RTC supply test */ | |
47c16975 MW |
395 | err = abx500_mask_and_set_register_interruptible(&pdev->dev, AB8500_RTC, |
396 | AB8500_RTC_STAT_REG, RTC_STATUS_DATA, RTC_STATUS_DATA); | |
0af62f4d VS |
397 | if (err < 0) |
398 | return err; | |
399 | ||
400 | /* Wait for reset by the PorRtc */ | |
012e52e1 | 401 | usleep_range(1000, 5000); |
0af62f4d | 402 | |
47c16975 MW |
403 | err = abx500_get_register_interruptible(&pdev->dev, AB8500_RTC, |
404 | AB8500_RTC_STAT_REG, &rtc_ctrl); | |
405 | if (err < 0) | |
406 | return err; | |
0af62f4d VS |
407 | |
408 | /* Check if the RTC Supply fails */ | |
409 | if (!(rtc_ctrl & RTC_STATUS_DATA)) { | |
410 | dev_err(&pdev->dev, "RTC supply failure\n"); | |
411 | return -ENODEV; | |
412 | } | |
413 | ||
b62581e6 AL |
414 | device_init_wakeup(&pdev->dev, true); |
415 | ||
0af62f4d VS |
416 | rtc = rtc_device_register("ab8500-rtc", &pdev->dev, &ab8500_rtc_ops, |
417 | THIS_MODULE); | |
418 | if (IS_ERR(rtc)) { | |
419 | dev_err(&pdev->dev, "Registration failed\n"); | |
420 | err = PTR_ERR(rtc); | |
421 | return err; | |
422 | } | |
423 | ||
10d065e6 RM |
424 | err = request_threaded_irq(irq, NULL, rtc_alarm_handler, |
425 | IRQF_NO_SUSPEND, "ab8500-rtc", rtc); | |
0af62f4d VS |
426 | if (err < 0) { |
427 | rtc_device_unregister(rtc); | |
428 | return err; | |
429 | } | |
430 | ||
431 | platform_set_drvdata(pdev, rtc); | |
432 | ||
dda367ac MG |
433 | |
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 | ||
457 | static struct platform_driver ab8500_rtc_driver = { | |
458 | .driver = { | |
459 | .name = "ab8500-rtc", | |
460 | .owner = THIS_MODULE, | |
461 | }, | |
462 | .probe = ab8500_rtc_probe, | |
463 | .remove = __devexit_p(ab8500_rtc_remove), | |
464 | }; | |
465 | ||
466 | static int __init ab8500_rtc_init(void) | |
467 | { | |
468 | return platform_driver_register(&ab8500_rtc_driver); | |
469 | } | |
470 | ||
471 | static void __exit ab8500_rtc_exit(void) | |
472 | { | |
473 | platform_driver_unregister(&ab8500_rtc_driver); | |
474 | } | |
475 | ||
476 | module_init(ab8500_rtc_init); | |
477 | module_exit(ab8500_rtc_exit); | |
478 | MODULE_AUTHOR("Virupax Sadashivpetimath <virupax.sadashivpetimath@stericsson.com>"); | |
479 | MODULE_DESCRIPTION("AB8500 RTC Driver"); | |
480 | MODULE_LICENSE("GPL v2"); |