tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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>
17#include <linux/mfd/abx500.h>
18#include <linux/mfd/abx500/ab8500.h>
19#include <linux/delay.h>
20#include <linux/of.h>
21#include <linux/pm_wakeirq.h>
22
23#define AB8500_RTC_SOFF_STAT_REG 0x00
24#define AB8500_RTC_CC_CONF_REG 0x01
25#define AB8500_RTC_READ_REQ_REG 0x02
26#define AB8500_RTC_WATCH_TSECMID_REG 0x03
27#define AB8500_RTC_WATCH_TSECHI_REG 0x04
28#define AB8500_RTC_WATCH_TMIN_LOW_REG 0x05
29#define AB8500_RTC_WATCH_TMIN_MID_REG 0x06
30#define AB8500_RTC_WATCH_TMIN_HI_REG 0x07
31#define AB8500_RTC_ALRM_MIN_LOW_REG 0x08
32#define AB8500_RTC_ALRM_MIN_MID_REG 0x09
33#define AB8500_RTC_ALRM_MIN_HI_REG 0x0A
34#define AB8500_RTC_STAT_REG 0x0B
35#define AB8500_RTC_BKUP_CHG_REG 0x0C
36#define AB8500_RTC_FORCE_BKUP_REG 0x0D
37#define AB8500_RTC_CALIB_REG 0x0E
38#define AB8500_RTC_SWITCH_STAT_REG 0x0F
39
40/* RtcReadRequest bits */
41#define RTC_READ_REQUEST 0x01
42#define RTC_WRITE_REQUEST 0x02
43
44/* RtcCtrl bits */
45#define RTC_ALARM_ENA 0x04
46#define RTC_STATUS_DATA 0x01
47
48#define COUNTS_PER_SEC (0xF000 / 60)
49#define AB8500_RTC_EPOCH 2000
50
51static const u8 ab8500_rtc_time_regs[] = {
52 AB8500_RTC_WATCH_TMIN_HI_REG, AB8500_RTC_WATCH_TMIN_MID_REG,
53 AB8500_RTC_WATCH_TMIN_LOW_REG, AB8500_RTC_WATCH_TSECHI_REG,
54 AB8500_RTC_WATCH_TSECMID_REG
55};
56
57static const u8 ab8500_rtc_alarm_regs[] = {
58 AB8500_RTC_ALRM_MIN_HI_REG, AB8500_RTC_ALRM_MIN_MID_REG,
59 AB8500_RTC_ALRM_MIN_LOW_REG
60};
61
62/* Calculate the seconds from 1970 to 01-01-2000 00:00:00 */
63static unsigned long get_elapsed_seconds(int year)
64{
65 unsigned long secs;
66 struct rtc_time tm = {
67 .tm_year = year - 1900,
68 .tm_mday = 1,
69 };
70
71 /*
72 * This function calculates secs from 1970 and not from
73 * 1900, even if we supply the offset from year 1900.
74 */
75 rtc_tm_to_time(&tm, &secs);
76 return secs;
77}
78
79static int ab8500_rtc_read_time(struct device *dev, struct rtc_time *tm)
80{
81 unsigned long timeout = jiffies + HZ;
82 int retval, i;
83 unsigned long mins, secs;
84 unsigned char buf[ARRAY_SIZE(ab8500_rtc_time_regs)];
85 u8 value;
86
87 /* Request a data read */
88 retval = abx500_set_register_interruptible(dev,
89 AB8500_RTC, AB8500_RTC_READ_REQ_REG, RTC_READ_REQUEST);
90 if (retval < 0)
91 return retval;
92
93 /* Wait for some cycles after enabling the rtc read in ab8500 */
94 while (time_before(jiffies, timeout)) {
95 retval = abx500_get_register_interruptible(dev,
96 AB8500_RTC, AB8500_RTC_READ_REQ_REG, &value);
97 if (retval < 0)
98 return retval;
99
100 if (!(value & RTC_READ_REQUEST))
101 break;
102
103 usleep_range(1000, 5000);
104 }
105
106 /* Read the Watchtime registers */
107 for (i = 0; i < ARRAY_SIZE(ab8500_rtc_time_regs); i++) {
108 retval = abx500_get_register_interruptible(dev,
109 AB8500_RTC, ab8500_rtc_time_regs[i], &value);
110 if (retval < 0)
111 return retval;
112 buf[i] = value;
113 }
114
115 mins = (buf[0] << 16) | (buf[1] << 8) | buf[2];
116
117 secs = (buf[3] << 8) | buf[4];
118 secs = secs / COUNTS_PER_SEC;
119 secs = secs + (mins * 60);
120
121 /* Add back the initially subtracted number of seconds */
122 secs += get_elapsed_seconds(AB8500_RTC_EPOCH);
123
124 rtc_time_to_tm(secs, tm);
125 return 0;
126}
127
128static int ab8500_rtc_set_time(struct device *dev, struct rtc_time *tm)
129{
130 int retval, i;
131 unsigned char buf[ARRAY_SIZE(ab8500_rtc_time_regs)];
132 unsigned long no_secs, no_mins, secs = 0;
133
134 if (tm->tm_year < (AB8500_RTC_EPOCH - 1900)) {
135 dev_dbg(dev, "year should be equal to or greater than %d\n",
136 AB8500_RTC_EPOCH);
137 return -EINVAL;
138 }
139
140 /* Get the number of seconds since 1970 */
141 rtc_tm_to_time(tm, &secs);
142
143 /*
144 * Convert it to the number of seconds since 01-01-2000 00:00:00, since
145 * we only have a small counter in the RTC.
146 */
147 secs -= get_elapsed_seconds(AB8500_RTC_EPOCH);
148
149 no_mins = secs / 60;
150
151 no_secs = secs % 60;
152 /* Make the seconds count as per the RTC resolution */
153 no_secs = no_secs * COUNTS_PER_SEC;
154
155 buf[4] = no_secs & 0xFF;
156 buf[3] = (no_secs >> 8) & 0xFF;
157
158 buf[2] = no_mins & 0xFF;
159 buf[1] = (no_mins >> 8) & 0xFF;
160 buf[0] = (no_mins >> 16) & 0xFF;
161
162 for (i = 0; i < ARRAY_SIZE(ab8500_rtc_time_regs); i++) {
163 retval = abx500_set_register_interruptible(dev, AB8500_RTC,
164 ab8500_rtc_time_regs[i], buf[i]);
165 if (retval < 0)
166 return retval;
167 }
168
169 /* Request a data write */
170 return abx500_set_register_interruptible(dev, AB8500_RTC,
171 AB8500_RTC_READ_REQ_REG, RTC_WRITE_REQUEST);
172}
173
174static int ab8500_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
175{
176 int retval, i;
177 u8 rtc_ctrl, value;
178 unsigned char buf[ARRAY_SIZE(ab8500_rtc_alarm_regs)];
179 unsigned long secs, mins;
180
181 /* Check if the alarm is enabled or not */
182 retval = abx500_get_register_interruptible(dev, AB8500_RTC,
183 AB8500_RTC_STAT_REG, &rtc_ctrl);
184 if (retval < 0)
185 return retval;
186
187 if (rtc_ctrl & RTC_ALARM_ENA)
188 alarm->enabled = 1;
189 else
190 alarm->enabled = 0;
191
192 alarm->pending = 0;
193
194 for (i = 0; i < ARRAY_SIZE(ab8500_rtc_alarm_regs); i++) {
195 retval = abx500_get_register_interruptible(dev, AB8500_RTC,
196 ab8500_rtc_alarm_regs[i], &value);
197 if (retval < 0)
198 return retval;
199 buf[i] = value;
200 }
201
202 mins = (buf[0] << 16) | (buf[1] << 8) | (buf[2]);
203 secs = mins * 60;
204
205 /* Add back the initially subtracted number of seconds */
206 secs += get_elapsed_seconds(AB8500_RTC_EPOCH);
207
208 rtc_time_to_tm(secs, &alarm->time);
209
210 return rtc_valid_tm(&alarm->time);
211}
212
213static int ab8500_rtc_irq_enable(struct device *dev, unsigned int enabled)
214{
215 return abx500_mask_and_set_register_interruptible(dev, AB8500_RTC,
216 AB8500_RTC_STAT_REG, RTC_ALARM_ENA,
217 enabled ? RTC_ALARM_ENA : 0);
218}
219
220static int ab8500_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
221{
222 int retval, i;
223 unsigned char buf[ARRAY_SIZE(ab8500_rtc_alarm_regs)];
224 unsigned long mins, secs = 0, cursec = 0;
225 struct rtc_time curtm;
226
227 if (alarm->time.tm_year < (AB8500_RTC_EPOCH - 1900)) {
228 dev_dbg(dev, "year should be equal to or greater than %d\n",
229 AB8500_RTC_EPOCH);
230 return -EINVAL;
231 }
232
233 /* Get the number of seconds since 1970 */
234 rtc_tm_to_time(&alarm->time, &secs);
235
236 /*
237 * Check whether alarm is set less than 1min.
238 * Since our RTC doesn't support alarm resolution less than 1min,
239 * return -EINVAL, so UIE EMUL can take it up, incase of UIE_ON
240 */
241 ab8500_rtc_read_time(dev, &curtm); /* Read current time */
242 rtc_tm_to_time(&curtm, &cursec);
243 if ((secs - cursec) < 59) {
244 dev_dbg(dev, "Alarm less than 1 minute not supported\r\n");
245 return -EINVAL;
246 }
247
248 /*
249 * Convert it to the number of seconds since 01-01-2000 00:00:00, since
250 * we only have a small counter in the RTC.
251 */
252 secs -= get_elapsed_seconds(AB8500_RTC_EPOCH);
253
254 mins = secs / 60;
255
256 buf[2] = mins & 0xFF;
257 buf[1] = (mins >> 8) & 0xFF;
258 buf[0] = (mins >> 16) & 0xFF;
259
260 /* Set the alarm time */
261 for (i = 0; i < ARRAY_SIZE(ab8500_rtc_alarm_regs); i++) {
262 retval = abx500_set_register_interruptible(dev, AB8500_RTC,
263 ab8500_rtc_alarm_regs[i], buf[i]);
264 if (retval < 0)
265 return retval;
266 }
267
268 return ab8500_rtc_irq_enable(dev, alarm->enabled);
269}
270
271static int ab8500_rtc_set_calibration(struct device *dev, int calibration)
272{
273 int retval;
274 u8 rtccal = 0;
275
276 /*
277 * Check that the calibration value (which is in units of 0.5
278 * parts-per-million) is in the AB8500's range for RtcCalibration
279 * register. -128 (0x80) is not permitted because the AB8500 uses
280 * a sign-bit rather than two's complement, so 0x80 is just another
281 * representation of zero.
282 */
283 if ((calibration < -127) || (calibration > 127)) {
284 dev_err(dev, "RtcCalibration value outside permitted range\n");
285 return -EINVAL;
286 }
287
288 /*
289 * The AB8500 uses sign (in bit7) and magnitude (in bits0-7)
290 * so need to convert to this sort of representation before writing
291 * into RtcCalibration register...
292 */
293 if (calibration >= 0)
294 rtccal = 0x7F & calibration;
295 else
296 rtccal = ~(calibration - 1) | 0x80;
297
298 retval = abx500_set_register_interruptible(dev, AB8500_RTC,
299 AB8500_RTC_CALIB_REG, rtccal);
300
301 return retval;
302}
303
304static int ab8500_rtc_get_calibration(struct device *dev, int *calibration)
305{
306 int retval;
307 u8 rtccal = 0;
308
309 retval = abx500_get_register_interruptible(dev, AB8500_RTC,
310 AB8500_RTC_CALIB_REG, &rtccal);
311 if (retval >= 0) {
312 /*
313 * The AB8500 uses sign (in bit7) and magnitude (in bits0-7)
314 * so need to convert value from RtcCalibration register into
315 * a two's complement signed value...
316 */
317 if (rtccal & 0x80)
318 *calibration = 0 - (rtccal & 0x7F);
319 else
320 *calibration = 0x7F & rtccal;
321 }
322
323 return retval;
324}
325
326static ssize_t ab8500_sysfs_store_rtc_calibration(struct device *dev,
327 struct device_attribute *attr,
328 const char *buf, size_t count)
329{
330 int retval;
331 int calibration = 0;
332
333 if (sscanf(buf, " %i ", &calibration) != 1) {
334 dev_err(dev, "Failed to store RTC calibration attribute\n");
335 return -EINVAL;
336 }
337
338 retval = ab8500_rtc_set_calibration(dev, calibration);
339
340 return retval ? retval : count;
341}
342
343static ssize_t ab8500_sysfs_show_rtc_calibration(struct device *dev,
344 struct device_attribute *attr, char *buf)
345{
346 int retval = 0;
347 int calibration = 0;
348
349 retval = ab8500_rtc_get_calibration(dev, &calibration);
350 if (retval < 0) {
351 dev_err(dev, "Failed to read RTC calibration attribute\n");
352 sprintf(buf, "0\n");
353 return retval;
354 }
355
356 return sprintf(buf, "%d\n", calibration);
357}
358
359static DEVICE_ATTR(rtc_calibration, S_IRUGO | S_IWUSR,
360 ab8500_sysfs_show_rtc_calibration,
361 ab8500_sysfs_store_rtc_calibration);
362
363static int ab8500_sysfs_rtc_register(struct device *dev)
364{
365 return device_create_file(dev, &dev_attr_rtc_calibration);
366}
367
368static void ab8500_sysfs_rtc_unregister(struct device *dev)
369{
370 device_remove_file(dev, &dev_attr_rtc_calibration);
371}
372
373static irqreturn_t rtc_alarm_handler(int irq, void *data)
374{
375 struct rtc_device *rtc = data;
376 unsigned long events = RTC_IRQF | RTC_AF;
377
378 dev_dbg(&rtc->dev, "%s\n", __func__);
379 rtc_update_irq(rtc, 1, events);
380
381 return IRQ_HANDLED;
382}
383
384static const struct rtc_class_ops ab8500_rtc_ops = {
385 .read_time = ab8500_rtc_read_time,
386 .set_time = ab8500_rtc_set_time,
387 .read_alarm = ab8500_rtc_read_alarm,
388 .set_alarm = ab8500_rtc_set_alarm,
389 .alarm_irq_enable = ab8500_rtc_irq_enable,
390};
391
392static const struct platform_device_id ab85xx_rtc_ids[] = {
393 { "ab8500-rtc", (kernel_ulong_t)&ab8500_rtc_ops, },
394 { /* sentinel */ }
395};
396MODULE_DEVICE_TABLE(platform, ab85xx_rtc_ids);
397
398static int ab8500_rtc_probe(struct platform_device *pdev)
399{
400 const struct platform_device_id *platid = platform_get_device_id(pdev);
401 int err;
402 struct rtc_device *rtc;
403 u8 rtc_ctrl;
404 int irq;
405
406 irq = platform_get_irq_byname(pdev, "ALARM");
407 if (irq < 0)
408 return irq;
409
410 /* For RTC supply test */
411 err = abx500_mask_and_set_register_interruptible(&pdev->dev, AB8500_RTC,
412 AB8500_RTC_STAT_REG, RTC_STATUS_DATA, RTC_STATUS_DATA);
413 if (err < 0)
414 return err;
415
416 /* Wait for reset by the PorRtc */
417 usleep_range(1000, 5000);
418
419 err = abx500_get_register_interruptible(&pdev->dev, AB8500_RTC,
420 AB8500_RTC_STAT_REG, &rtc_ctrl);
421 if (err < 0)
422 return err;
423
424 /* Check if the RTC Supply fails */
425 if (!(rtc_ctrl & RTC_STATUS_DATA)) {
426 dev_err(&pdev->dev, "RTC supply failure\n");
427 return -ENODEV;
428 }
429
430 device_init_wakeup(&pdev->dev, true);
431
432 rtc = devm_rtc_device_register(&pdev->dev, "ab8500-rtc",
433 (struct rtc_class_ops *)platid->driver_data,
434 THIS_MODULE);
435 if (IS_ERR(rtc)) {
436 dev_err(&pdev->dev, "Registration failed\n");
437 err = PTR_ERR(rtc);
438 return err;
439 }
440
441 err = devm_request_threaded_irq(&pdev->dev, irq, NULL,
442 rtc_alarm_handler, IRQF_ONESHOT,
443 "ab8500-rtc", rtc);
444 if (err < 0)
445 return err;
446
447 dev_pm_set_wake_irq(&pdev->dev, irq);
448 platform_set_drvdata(pdev, rtc);
449
450 err = ab8500_sysfs_rtc_register(&pdev->dev);
451 if (err) {
452 dev_err(&pdev->dev, "sysfs RTC failed to register\n");
453 return err;
454 }
455
456 rtc->uie_unsupported = 1;
457
458 return 0;
459}
460
461static int ab8500_rtc_remove(struct platform_device *pdev)
462{
463 dev_pm_clear_wake_irq(&pdev->dev);
464 device_init_wakeup(&pdev->dev, false);
465 ab8500_sysfs_rtc_unregister(&pdev->dev);
466
467 return 0;
468}
469
470static struct platform_driver ab8500_rtc_driver = {
471 .driver = {
472 .name = "ab8500-rtc",
473 },
474 .probe = ab8500_rtc_probe,
475 .remove = ab8500_rtc_remove,
476 .id_table = ab85xx_rtc_ids,
477};
478
479module_platform_driver(ab8500_rtc_driver);
480
481MODULE_AUTHOR("Virupax Sadashivpetimath <virupax.sadashivpetimath@stericsson.com>");
482MODULE_DESCRIPTION("AB8500 RTC Driver");
483MODULE_LICENSE("GPL v2");