1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) ST-Ericsson SA 2010
4 *
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
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
54 };
55
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
59 };
60
ab8500_rtc_read_time(struct device * dev,struct rtc_time * tm)61 static int ab8500_rtc_read_time(struct device *dev, struct rtc_time *tm)
62 {
63 unsigned long timeout = jiffies + HZ;
64 int retval, i;
65 unsigned long mins, secs;
66 unsigned char buf[ARRAY_SIZE(ab8500_rtc_time_regs)];
67 u8 value;
68
69 /* Request a data read */
70 retval = abx500_set_register_interruptible(dev,
71 AB8500_RTC, AB8500_RTC_READ_REQ_REG, RTC_READ_REQUEST);
72 if (retval < 0)
73 return retval;
74
75 /* Wait for some cycles after enabling the rtc read in ab8500 */
76 while (time_before(jiffies, timeout)) {
77 retval = abx500_get_register_interruptible(dev,
78 AB8500_RTC, AB8500_RTC_READ_REQ_REG, &value);
79 if (retval < 0)
80 return retval;
81
82 if (!(value & RTC_READ_REQUEST))
83 break;
84
85 usleep_range(1000, 5000);
86 }
87
88 /* Read the Watchtime registers */
89 for (i = 0; i < ARRAY_SIZE(ab8500_rtc_time_regs); i++) {
90 retval = abx500_get_register_interruptible(dev,
91 AB8500_RTC, ab8500_rtc_time_regs[i], &value);
92 if (retval < 0)
93 return retval;
94 buf[i] = value;
95 }
96
97 mins = (buf[0] << 16) | (buf[1] << 8) | buf[2];
98
99 secs = (buf[3] << 8) | buf[4];
100 secs = secs / COUNTS_PER_SEC;
101 secs = secs + (mins * 60);
102
103 rtc_time_to_tm(secs, tm);
104 return 0;
105 }
106
ab8500_rtc_set_time(struct device * dev,struct rtc_time * tm)107 static int ab8500_rtc_set_time(struct device *dev, struct rtc_time *tm)
108 {
109 int retval, i;
110 unsigned char buf[ARRAY_SIZE(ab8500_rtc_time_regs)];
111 unsigned long no_secs, no_mins, secs = 0;
112
113 rtc_tm_to_time(tm, &secs);
114
115 no_mins = secs / 60;
116
117 no_secs = secs % 60;
118 /* Make the seconds count as per the RTC resolution */
119 no_secs = no_secs * COUNTS_PER_SEC;
120
121 buf[4] = no_secs & 0xFF;
122 buf[3] = (no_secs >> 8) & 0xFF;
123
124 buf[2] = no_mins & 0xFF;
125 buf[1] = (no_mins >> 8) & 0xFF;
126 buf[0] = (no_mins >> 16) & 0xFF;
127
128 for (i = 0; i < ARRAY_SIZE(ab8500_rtc_time_regs); i++) {
129 retval = abx500_set_register_interruptible(dev, AB8500_RTC,
130 ab8500_rtc_time_regs[i], buf[i]);
131 if (retval < 0)
132 return retval;
133 }
134
135 /* Request a data write */
136 return abx500_set_register_interruptible(dev, AB8500_RTC,
137 AB8500_RTC_READ_REQ_REG, RTC_WRITE_REQUEST);
138 }
139
ab8500_rtc_read_alarm(struct device * dev,struct rtc_wkalrm * alarm)140 static int ab8500_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
141 {
142 int retval, i;
143 u8 rtc_ctrl, value;
144 unsigned char buf[ARRAY_SIZE(ab8500_rtc_alarm_regs)];
145 unsigned long secs, mins;
146
147 /* Check if the alarm is enabled or not */
148 retval = abx500_get_register_interruptible(dev, AB8500_RTC,
149 AB8500_RTC_STAT_REG, &rtc_ctrl);
150 if (retval < 0)
151 return retval;
152
153 if (rtc_ctrl & RTC_ALARM_ENA)
154 alarm->enabled = 1;
155 else
156 alarm->enabled = 0;
157
158 alarm->pending = 0;
159
160 for (i = 0; i < ARRAY_SIZE(ab8500_rtc_alarm_regs); i++) {
161 retval = abx500_get_register_interruptible(dev, AB8500_RTC,
162 ab8500_rtc_alarm_regs[i], &value);
163 if (retval < 0)
164 return retval;
165 buf[i] = value;
166 }
167
168 mins = (buf[0] << 16) | (buf[1] << 8) | (buf[2]);
169 secs = mins * 60;
170
171 rtc_time_to_tm(secs, &alarm->time);
172
173 return 0;
174 }
175
ab8500_rtc_irq_enable(struct device * dev,unsigned int enabled)176 static int ab8500_rtc_irq_enable(struct device *dev, unsigned int enabled)
177 {
178 return abx500_mask_and_set_register_interruptible(dev, AB8500_RTC,
179 AB8500_RTC_STAT_REG, RTC_ALARM_ENA,
180 enabled ? RTC_ALARM_ENA : 0);
181 }
182
ab8500_rtc_set_alarm(struct device * dev,struct rtc_wkalrm * alarm)183 static int ab8500_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
184 {
185 int retval, i;
186 unsigned char buf[ARRAY_SIZE(ab8500_rtc_alarm_regs)];
187 unsigned long mins, secs = 0, cursec = 0;
188 struct rtc_time curtm;
189
190 /* Get the number of seconds since 1970 */
191 rtc_tm_to_time(&alarm->time, &secs);
192
193 /*
194 * Check whether alarm is set less than 1min.
195 * Since our RTC doesn't support alarm resolution less than 1min,
196 * return -EINVAL, so UIE EMUL can take it up, incase of UIE_ON
197 */
198 ab8500_rtc_read_time(dev, &curtm); /* Read current time */
199 rtc_tm_to_time(&curtm, &cursec);
200 if ((secs - cursec) < 59) {
201 dev_dbg(dev, "Alarm less than 1 minute not supported\r\n");
202 return -EINVAL;
203 }
204
205 mins = secs / 60;
206
207 buf[2] = mins & 0xFF;
208 buf[1] = (mins >> 8) & 0xFF;
209 buf[0] = (mins >> 16) & 0xFF;
210
211 /* Set the alarm time */
212 for (i = 0; i < ARRAY_SIZE(ab8500_rtc_alarm_regs); i++) {
213 retval = abx500_set_register_interruptible(dev, AB8500_RTC,
214 ab8500_rtc_alarm_regs[i], buf[i]);
215 if (retval < 0)
216 return retval;
217 }
218
219 return ab8500_rtc_irq_enable(dev, alarm->enabled);
220 }
221
ab8500_rtc_set_calibration(struct device * dev,int calibration)222 static int ab8500_rtc_set_calibration(struct device *dev, int calibration)
223 {
224 int retval;
225 u8 rtccal = 0;
226
227 /*
228 * Check that the calibration value (which is in units of 0.5
229 * parts-per-million) is in the AB8500's range for RtcCalibration
230 * register. -128 (0x80) is not permitted because the AB8500 uses
231 * a sign-bit rather than two's complement, so 0x80 is just another
232 * representation of zero.
233 */
234 if ((calibration < -127) || (calibration > 127)) {
235 dev_err(dev, "RtcCalibration value outside permitted range\n");
236 return -EINVAL;
237 }
238
239 /*
240 * The AB8500 uses sign (in bit7) and magnitude (in bits0-7)
241 * so need to convert to this sort of representation before writing
242 * into RtcCalibration register...
243 */
244 if (calibration >= 0)
245 rtccal = 0x7F & calibration;
246 else
247 rtccal = ~(calibration - 1) | 0x80;
248
249 retval = abx500_set_register_interruptible(dev, AB8500_RTC,
250 AB8500_RTC_CALIB_REG, rtccal);
251
252 return retval;
253 }
254
ab8500_rtc_get_calibration(struct device * dev,int * calibration)255 static int ab8500_rtc_get_calibration(struct device *dev, int *calibration)
256 {
257 int retval;
258 u8 rtccal = 0;
259
260 retval = abx500_get_register_interruptible(dev, AB8500_RTC,
261 AB8500_RTC_CALIB_REG, &rtccal);
262 if (retval >= 0) {
263 /*
264 * The AB8500 uses sign (in bit7) and magnitude (in bits0-7)
265 * so need to convert value from RtcCalibration register into
266 * a two's complement signed value...
267 */
268 if (rtccal & 0x80)
269 *calibration = 0 - (rtccal & 0x7F);
270 else
271 *calibration = 0x7F & rtccal;
272 }
273
274 return retval;
275 }
276
ab8500_sysfs_store_rtc_calibration(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)277 static ssize_t ab8500_sysfs_store_rtc_calibration(struct device *dev,
278 struct device_attribute *attr,
279 const char *buf, size_t count)
280 {
281 int retval;
282 int calibration = 0;
283
284 if (sscanf(buf, " %i ", &calibration) != 1) {
285 dev_err(dev, "Failed to store RTC calibration attribute\n");
286 return -EINVAL;
287 }
288
289 retval = ab8500_rtc_set_calibration(dev, calibration);
290
291 return retval ? retval : count;
292 }
293
ab8500_sysfs_show_rtc_calibration(struct device * dev,struct device_attribute * attr,char * buf)294 static ssize_t ab8500_sysfs_show_rtc_calibration(struct device *dev,
295 struct device_attribute *attr, char *buf)
296 {
297 int retval = 0;
298 int calibration = 0;
299
300 retval = ab8500_rtc_get_calibration(dev, &calibration);
301 if (retval < 0) {
302 dev_err(dev, "Failed to read RTC calibration attribute\n");
303 sprintf(buf, "0\n");
304 return retval;
305 }
306
307 return sprintf(buf, "%d\n", calibration);
308 }
309
310 static DEVICE_ATTR(rtc_calibration, S_IRUGO | S_IWUSR,
311 ab8500_sysfs_show_rtc_calibration,
312 ab8500_sysfs_store_rtc_calibration);
313
314 static struct attribute *ab8500_rtc_attrs[] = {
315 &dev_attr_rtc_calibration.attr,
316 NULL
317 };
318
319 static const struct attribute_group ab8500_rtc_sysfs_files = {
320 .attrs = ab8500_rtc_attrs,
321 };
322
rtc_alarm_handler(int irq,void * data)323 static irqreturn_t rtc_alarm_handler(int irq, void *data)
324 {
325 struct rtc_device *rtc = data;
326 unsigned long events = RTC_IRQF | RTC_AF;
327
328 dev_dbg(&rtc->dev, "%s\n", __func__);
329 rtc_update_irq(rtc, 1, events);
330
331 return IRQ_HANDLED;
332 }
333
334 static const struct rtc_class_ops ab8500_rtc_ops = {
335 .read_time = ab8500_rtc_read_time,
336 .set_time = ab8500_rtc_set_time,
337 .read_alarm = ab8500_rtc_read_alarm,
338 .set_alarm = ab8500_rtc_set_alarm,
339 .alarm_irq_enable = ab8500_rtc_irq_enable,
340 };
341
342 static const struct platform_device_id ab85xx_rtc_ids[] = {
343 { "ab8500-rtc", (kernel_ulong_t)&ab8500_rtc_ops, },
344 { /* sentinel */ }
345 };
346 MODULE_DEVICE_TABLE(platform, ab85xx_rtc_ids);
347
ab8500_rtc_probe(struct platform_device * pdev)348 static int ab8500_rtc_probe(struct platform_device *pdev)
349 {
350 const struct platform_device_id *platid = platform_get_device_id(pdev);
351 int err;
352 struct rtc_device *rtc;
353 u8 rtc_ctrl;
354 int irq;
355
356 irq = platform_get_irq_byname(pdev, "ALARM");
357 if (irq < 0)
358 return irq;
359
360 /* For RTC supply test */
361 err = abx500_mask_and_set_register_interruptible(&pdev->dev, AB8500_RTC,
362 AB8500_RTC_STAT_REG, RTC_STATUS_DATA, RTC_STATUS_DATA);
363 if (err < 0)
364 return err;
365
366 /* Wait for reset by the PorRtc */
367 usleep_range(1000, 5000);
368
369 err = abx500_get_register_interruptible(&pdev->dev, AB8500_RTC,
370 AB8500_RTC_STAT_REG, &rtc_ctrl);
371 if (err < 0)
372 return err;
373
374 /* Check if the RTC Supply fails */
375 if (!(rtc_ctrl & RTC_STATUS_DATA)) {
376 dev_err(&pdev->dev, "RTC supply failure\n");
377 return -ENODEV;
378 }
379
380 device_init_wakeup(&pdev->dev, true);
381
382 rtc = devm_rtc_allocate_device(&pdev->dev);
383 if (IS_ERR(rtc))
384 return PTR_ERR(rtc);
385
386 rtc->ops = (struct rtc_class_ops *)platid->driver_data;
387
388 err = devm_request_threaded_irq(&pdev->dev, irq, NULL,
389 rtc_alarm_handler, IRQF_ONESHOT,
390 "ab8500-rtc", rtc);
391 if (err < 0)
392 return err;
393
394 dev_pm_set_wake_irq(&pdev->dev, irq);
395 platform_set_drvdata(pdev, rtc);
396
397 rtc->uie_unsupported = 1;
398
399 rtc->range_max = (1ULL << 24) * 60 - 1; // 24-bit minutes + 59 secs
400 rtc->start_secs = RTC_TIMESTAMP_BEGIN_2000;
401 rtc->set_start_time = true;
402
403 err = rtc_add_group(rtc, &ab8500_rtc_sysfs_files);
404 if (err)
405 return err;
406
407 return rtc_register_device(rtc);
408 }
409
ab8500_rtc_remove(struct platform_device * pdev)410 static int ab8500_rtc_remove(struct platform_device *pdev)
411 {
412 dev_pm_clear_wake_irq(&pdev->dev);
413 device_init_wakeup(&pdev->dev, false);
414
415 return 0;
416 }
417
418 static struct platform_driver ab8500_rtc_driver = {
419 .driver = {
420 .name = "ab8500-rtc",
421 },
422 .probe = ab8500_rtc_probe,
423 .remove = ab8500_rtc_remove,
424 .id_table = ab85xx_rtc_ids,
425 };
426
427 module_platform_driver(ab8500_rtc_driver);
428
429 MODULE_AUTHOR("Virupax Sadashivpetimath <virupax.sadashivpetimath@stericsson.com>");
430 MODULE_DESCRIPTION("AB8500 RTC Driver");
431 MODULE_LICENSE("GPL v2");
432
