1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * RTC driver for Rockchip RK808
4 *
5 * Copyright (c) 2014, Fuzhou Rockchip Electronics Co., Ltd
6 *
7 * Author: Chris Zhong <zyw@rock-chips.com>
8 * Author: Zhang Qing <zhangqing@rock-chips.com>
9 */
10
11 #include <linux/module.h>
12 #include <linux/kernel.h>
13 #include <linux/rtc.h>
14 #include <linux/bcd.h>
15 #include <linux/mfd/rk808.h>
16 #include <linux/platform_device.h>
17 #include <linux/i2c.h>
18
19 /* RTC_CTRL_REG bitfields */
20 #define BIT_RTC_CTRL_REG_STOP_RTC_M BIT(0)
21
22 /* RK808 has a shadowed register for saving a "frozen" RTC time.
23 * When user setting "GET_TIME" to 1, the time will save in this shadowed
24 * register. If set "READSEL" to 1, user read rtc time register, actually
25 * get the time of that moment. If we need the real time, clr this bit.
26 */
27 #define BIT_RTC_CTRL_REG_RTC_GET_TIME BIT(6)
28 #define BIT_RTC_CTRL_REG_RTC_READSEL_M BIT(7)
29 #define BIT_RTC_INTERRUPTS_REG_IT_ALARM_M BIT(3)
30 #define RTC_STATUS_MASK 0xFE
31 #define RTC_ALARM_STATUS BIT(6)
32
33 #define SECONDS_REG_MSK 0x7F
34 #define MINUTES_REG_MAK 0x7F
35 #define HOURS_REG_MSK 0x3F
36 #define DAYS_REG_MSK 0x3F
37 #define MONTHS_REG_MSK 0x1F
38 #define YEARS_REG_MSK 0xFF
39 #define WEEKS_REG_MSK 0x7
40
41 #define RTC_NEED_TRANSITIONS BIT(0)
42 /* REG_SECONDS_REG through REG_YEARS_REG is how many registers? */
43
44 #define NUM_TIME_REGS (RK808_WEEKS_REG - RK808_SECONDS_REG + 1)
45 #define NUM_ALARM_REGS (RK808_ALARM_YEARS_REG - RK808_ALARM_SECONDS_REG + 1)
46
47 struct rk_rtc_compat_reg {
48 unsigned int ctrl_reg;
49 unsigned int status_reg;
50 unsigned int alarm_seconds_reg;
51 unsigned int int_reg;
52 unsigned int seconds_reg;
53 };
54
55 struct rk808_rtc {
56 struct rk808 *rk808;
57 struct rtc_device *rtc;
58 struct rk_rtc_compat_reg *creg;
59 int irq;
60 unsigned int flag;
61 };
62
63 /*
64 * The Rockchip calendar used by the RK808 counts November with 31 days. We use
65 * these translation functions to convert its dates to/from the Gregorian
66 * calendar used by the rest of the world. We arbitrarily define Jan 1st, 2016
67 * as the day when both calendars were in sync, and treat all other dates
68 * relative to that.
69 * NOTE: Other system software (e.g. firmware) that reads the same hardware must
70 * implement this exact same conversion algorithm, with the same anchor date.
71 */
nov2dec_transitions(struct rtc_time * tm)72 static time64_t nov2dec_transitions(struct rtc_time *tm)
73 {
74 return (tm->tm_year + 1900) - 2016 + (tm->tm_mon + 1 > 11 ? 1 : 0);
75 }
76
rockchip_to_gregorian(struct rtc_time * tm)77 static void rockchip_to_gregorian(struct rtc_time *tm)
78 {
79 /* If it's Nov 31st, rtc_tm_to_time64() will count that like Dec 1st */
80 time64_t time = rtc_tm_to_time64(tm);
81 rtc_time64_to_tm(time + nov2dec_transitions(tm) * 86400, tm);
82 }
83
gregorian_to_rockchip(struct rtc_time * tm)84 static void gregorian_to_rockchip(struct rtc_time *tm)
85 {
86 time64_t extra_days = nov2dec_transitions(tm);
87 time64_t time = rtc_tm_to_time64(tm);
88 rtc_time64_to_tm(time - extra_days * 86400, tm);
89
90 /* Compensate if we went back over Nov 31st (will work up to 2381) */
91 if (nov2dec_transitions(tm) < extra_days) {
92 if (tm->tm_mon + 1 == 11)
93 tm->tm_mday++; /* This may result in 31! */
94 else
95 rtc_time64_to_tm(time - (extra_days - 1) * 86400, tm);
96 }
97 }
98
99 /* Read current time and date in RTC */
rk808_rtc_readtime(struct device * dev,struct rtc_time * tm)100 static int rk808_rtc_readtime(struct device *dev, struct rtc_time *tm)
101 {
102 struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
103 struct rk808 *rk808 = rk808_rtc->rk808;
104 u8 rtc_data[NUM_TIME_REGS];
105 int ret;
106
107 /* Force an update of the shadowed registers right now */
108 ret = regmap_update_bits(rk808->regmap, rk808_rtc->creg->ctrl_reg,
109 BIT_RTC_CTRL_REG_RTC_GET_TIME,
110 BIT_RTC_CTRL_REG_RTC_GET_TIME);
111 if (ret) {
112 dev_err(dev, "Failed to update bits rtc_ctrl: %d\n", ret);
113 return ret;
114 }
115
116 /*
117 * After we set the GET_TIME bit, the rtc time can't be read
118 * immediately. So we should wait up to 31.25 us, about one cycle of
119 * 32khz. If we clear the GET_TIME bit here, the time of i2c transfer
120 * certainly more than 31.25us: 16 * 2.5us at 400kHz bus frequency.
121 */
122 ret = regmap_update_bits(rk808->regmap, rk808_rtc->creg->ctrl_reg,
123 BIT_RTC_CTRL_REG_RTC_GET_TIME,
124 0);
125 if (ret) {
126 dev_err(dev, "Failed to update bits rtc_ctrl: %d\n", ret);
127 return ret;
128 }
129
130 ret = regmap_bulk_read(rk808->regmap, rk808_rtc->creg->seconds_reg,
131 rtc_data, NUM_TIME_REGS);
132 if (ret) {
133 dev_err(dev, "Failed to bulk read rtc_data: %d\n", ret);
134 return ret;
135 }
136
137 tm->tm_sec = bcd2bin(rtc_data[0] & SECONDS_REG_MSK);
138 tm->tm_min = bcd2bin(rtc_data[1] & MINUTES_REG_MAK);
139 tm->tm_hour = bcd2bin(rtc_data[2] & HOURS_REG_MSK);
140 tm->tm_mday = bcd2bin(rtc_data[3] & DAYS_REG_MSK);
141 tm->tm_mon = (bcd2bin(rtc_data[4] & MONTHS_REG_MSK)) - 1;
142 tm->tm_year = (bcd2bin(rtc_data[5] & YEARS_REG_MSK)) + 100;
143 tm->tm_wday = bcd2bin(rtc_data[6] & WEEKS_REG_MSK);
144
145 if (rk808_rtc->flag & RTC_NEED_TRANSITIONS)
146 rockchip_to_gregorian(tm);
147
148 dev_dbg(dev, "RTC date/time %4d-%02d-%02d(%d) %02d:%02d:%02d\n",
149 1900 + tm->tm_year, tm->tm_mon + 1, tm->tm_mday,
150 tm->tm_wday, tm->tm_hour, tm->tm_min, tm->tm_sec);
151
152 return ret;
153 }
154
155 /* Set current time and date in RTC */
rk808_rtc_set_time(struct device * dev,struct rtc_time * tm)156 static int rk808_rtc_set_time(struct device *dev, struct rtc_time *tm)
157 {
158 struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
159 struct rk808 *rk808 = rk808_rtc->rk808;
160 u8 rtc_data[NUM_TIME_REGS];
161 int ret;
162
163 dev_dbg(dev, "set RTC date/time %4d-%02d-%02d(%d) %02d:%02d:%02d\n",
164 1900 + tm->tm_year, tm->tm_mon + 1, tm->tm_mday,
165 tm->tm_wday, tm->tm_hour, tm->tm_min, tm->tm_sec);
166
167 if (rk808_rtc->flag & RTC_NEED_TRANSITIONS)
168 gregorian_to_rockchip(tm);
169
170 rtc_data[0] = bin2bcd(tm->tm_sec);
171 rtc_data[1] = bin2bcd(tm->tm_min);
172 rtc_data[2] = bin2bcd(tm->tm_hour);
173 rtc_data[3] = bin2bcd(tm->tm_mday);
174 rtc_data[4] = bin2bcd(tm->tm_mon + 1);
175 rtc_data[5] = bin2bcd(tm->tm_year - 100);
176 rtc_data[6] = bin2bcd(tm->tm_wday);
177
178 /* Stop RTC while updating the RTC registers */
179 ret = regmap_update_bits(rk808->regmap, rk808_rtc->creg->ctrl_reg,
180 BIT_RTC_CTRL_REG_STOP_RTC_M,
181 BIT_RTC_CTRL_REG_STOP_RTC_M);
182 if (ret) {
183 dev_err(dev, "Failed to update RTC control: %d\n", ret);
184 return ret;
185 }
186
187 ret = regmap_bulk_write(rk808->regmap, rk808_rtc->creg->seconds_reg,
188 rtc_data, NUM_TIME_REGS);
189 if (ret) {
190 dev_err(dev, "Failed to bull write rtc_data: %d\n", ret);
191 return ret;
192 }
193 /* Start RTC again */
194 ret = regmap_update_bits(rk808->regmap, rk808_rtc->creg->ctrl_reg,
195 BIT_RTC_CTRL_REG_STOP_RTC_M, 0);
196 if (ret) {
197 dev_err(dev, "Failed to update RTC control: %d\n", ret);
198 return ret;
199 }
200 return 0;
201 }
202
203 /* Read alarm time and date in RTC */
rk808_rtc_readalarm(struct device * dev,struct rtc_wkalrm * alrm)204 static int rk808_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
205 {
206 struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
207 struct rk808 *rk808 = rk808_rtc->rk808;
208 u8 alrm_data[NUM_ALARM_REGS];
209 uint32_t int_reg;
210 int ret;
211
212 ret = regmap_bulk_read(rk808->regmap,
213 rk808_rtc->creg->alarm_seconds_reg,
214 alrm_data, NUM_ALARM_REGS);
215 if (ret) {
216 dev_err(dev, "Failed to read RTC alarm date REG: %d\n", ret);
217 return ret;
218 }
219
220 alrm->time.tm_sec = bcd2bin(alrm_data[0] & SECONDS_REG_MSK);
221 alrm->time.tm_min = bcd2bin(alrm_data[1] & MINUTES_REG_MAK);
222 alrm->time.tm_hour = bcd2bin(alrm_data[2] & HOURS_REG_MSK);
223 alrm->time.tm_mday = bcd2bin(alrm_data[3] & DAYS_REG_MSK);
224 alrm->time.tm_mon = (bcd2bin(alrm_data[4] & MONTHS_REG_MSK)) - 1;
225 alrm->time.tm_year = (bcd2bin(alrm_data[5] & YEARS_REG_MSK)) + 100;
226
227 if (rk808_rtc->flag & RTC_NEED_TRANSITIONS)
228 rockchip_to_gregorian(&alrm->time);
229
230 ret = regmap_read(rk808->regmap, rk808_rtc->creg->int_reg, &int_reg);
231 if (ret) {
232 dev_err(dev, "Failed to read RTC INT REG: %d\n", ret);
233 return ret;
234 }
235
236 dev_dbg(dev, "alrm read RTC date/time %ptRd(%d) %ptRt\n",
237 &alrm->time, alrm->time.tm_wday, &alrm->time);
238
239 alrm->enabled = (int_reg & BIT_RTC_INTERRUPTS_REG_IT_ALARM_M) ? 1 : 0;
240
241 return 0;
242 }
243
rk808_rtc_stop_alarm(struct rk808_rtc * rk808_rtc)244 static int rk808_rtc_stop_alarm(struct rk808_rtc *rk808_rtc)
245 {
246 struct rk808 *rk808 = rk808_rtc->rk808;
247 int ret;
248
249 ret = regmap_update_bits(rk808->regmap, rk808_rtc->creg->int_reg,
250 BIT_RTC_INTERRUPTS_REG_IT_ALARM_M, 0);
251
252 /*
253 * The rtc alarm status(BIT(6)) must be cleared after alarm 1s or
254 * after the alarm is disabled.
255 */
256 ret = regmap_write(rk808->regmap, rk808_rtc->creg->status_reg,
257 RTC_ALARM_STATUS);
258 return ret;
259 }
260
rk808_rtc_start_alarm(struct rk808_rtc * rk808_rtc)261 static int rk808_rtc_start_alarm(struct rk808_rtc *rk808_rtc)
262 {
263 struct rk808 *rk808 = rk808_rtc->rk808;
264 int ret;
265
266 ret = regmap_update_bits(rk808->regmap, rk808_rtc->creg->int_reg,
267 BIT_RTC_INTERRUPTS_REG_IT_ALARM_M,
268 BIT_RTC_INTERRUPTS_REG_IT_ALARM_M);
269
270 return ret;
271 }
272
rk808_rtc_setalarm(struct device * dev,struct rtc_wkalrm * alrm)273 static int rk808_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
274 {
275 struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
276 struct rk808 *rk808 = rk808_rtc->rk808;
277 u8 alrm_data[NUM_ALARM_REGS];
278 int ret;
279
280 ret = rk808_rtc_stop_alarm(rk808_rtc);
281 if (ret) {
282 dev_err(dev, "Failed to stop alarm: %d\n", ret);
283 return ret;
284 }
285 dev_dbg(dev, "alrm set RTC date/time %ptRd(%d) %ptRt\n",
286 &alrm->time, alrm->time.tm_wday, &alrm->time);
287
288 if (rk808_rtc->flag & RTC_NEED_TRANSITIONS)
289 gregorian_to_rockchip(&alrm->time);
290
291 alrm_data[0] = bin2bcd(alrm->time.tm_sec);
292 alrm_data[1] = bin2bcd(alrm->time.tm_min);
293 alrm_data[2] = bin2bcd(alrm->time.tm_hour);
294 alrm_data[3] = bin2bcd(alrm->time.tm_mday);
295 alrm_data[4] = bin2bcd(alrm->time.tm_mon + 1);
296 alrm_data[5] = bin2bcd(alrm->time.tm_year - 100);
297
298 ret = regmap_bulk_write(rk808->regmap,
299 rk808_rtc->creg->alarm_seconds_reg,
300 alrm_data, NUM_ALARM_REGS);
301 if (ret) {
302 dev_err(dev, "Failed to bulk write: %d\n", ret);
303 return ret;
304 }
305 if (alrm->enabled) {
306 ret = rk808_rtc_start_alarm(rk808_rtc);
307 if (ret) {
308 dev_err(dev, "Failed to start alarm: %d\n", ret);
309 return ret;
310 }
311 }
312 return 0;
313 }
314
rk808_rtc_alarm_irq_enable(struct device * dev,unsigned int enabled)315 static int rk808_rtc_alarm_irq_enable(struct device *dev,
316 unsigned int enabled)
317 {
318 struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
319
320 if (enabled)
321 return rk808_rtc_start_alarm(rk808_rtc);
322
323 return rk808_rtc_stop_alarm(rk808_rtc);
324 }
325
326 /*
327 * We will just handle setting the frequency and make use the framework for
328 * reading the periodic interupts.
329 *
330 * @freq: Current periodic IRQ freq:
331 * bit 0: every second
332 * bit 1: every minute
333 * bit 2: every hour
334 * bit 3: every day
335 */
rk808_alarm_irq(int irq,void * data)336 static irqreturn_t rk808_alarm_irq(int irq, void *data)
337 {
338 struct rk808_rtc *rk808_rtc = data;
339 struct rk808 *rk808 = rk808_rtc->rk808;
340 struct i2c_client *client = rk808->i2c;
341 int ret;
342
343 ret = regmap_write(rk808->regmap, rk808_rtc->creg->status_reg,
344 RTC_STATUS_MASK);
345 if (ret) {
346 dev_err(&client->dev,
347 "%s:Failed to update RTC status: %d\n", __func__, ret);
348 return ret;
349 }
350
351 rtc_update_irq(rk808_rtc->rtc, 1, RTC_IRQF | RTC_AF);
352 dev_dbg(&client->dev,
353 "%s:irq=%d\n", __func__, irq);
354 return IRQ_HANDLED;
355 }
356
357 static const struct rtc_class_ops rk808_rtc_ops = {
358 .read_time = rk808_rtc_readtime,
359 .set_time = rk808_rtc_set_time,
360 .read_alarm = rk808_rtc_readalarm,
361 .set_alarm = rk808_rtc_setalarm,
362 .alarm_irq_enable = rk808_rtc_alarm_irq_enable,
363 };
364
365 #ifdef CONFIG_PM_SLEEP
366 /* Turn off the alarm if it should not be a wake source. */
rk808_rtc_suspend(struct device * dev)367 static int rk808_rtc_suspend(struct device *dev)
368 {
369 struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
370
371 if (device_may_wakeup(dev))
372 enable_irq_wake(rk808_rtc->irq);
373
374 return 0;
375 }
376
377 /* Enable the alarm if it should be enabled (in case it was disabled to
378 * prevent use as a wake source).
379 */
rk808_rtc_resume(struct device * dev)380 static int rk808_rtc_resume(struct device *dev)
381 {
382 struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
383
384 if (device_may_wakeup(dev))
385 disable_irq_wake(rk808_rtc->irq);
386
387 return 0;
388 }
389 #endif
390
391 static SIMPLE_DEV_PM_OPS(rk808_rtc_pm_ops,
392 rk808_rtc_suspend, rk808_rtc_resume);
393
394 static struct rk_rtc_compat_reg rk808_creg = {
395 .ctrl_reg = RK808_RTC_CTRL_REG,
396 .status_reg = RK808_RTC_STATUS_REG,
397 .alarm_seconds_reg = RK808_ALARM_SECONDS_REG,
398 .int_reg = RK808_RTC_INT_REG,
399 .seconds_reg = RK808_SECONDS_REG,
400 };
401
402 static struct rk_rtc_compat_reg rk817_creg = {
403 .ctrl_reg = RK817_RTC_CTRL_REG,
404 .status_reg = RK817_RTC_STATUS_REG,
405 .alarm_seconds_reg = RK817_ALARM_SECONDS_REG,
406 .int_reg = RK817_RTC_INT_REG,
407 .seconds_reg = RK817_SECONDS_REG,
408 };
409
rk808_rtc_probe(struct platform_device * pdev)410 static int rk808_rtc_probe(struct platform_device *pdev)
411 {
412 struct rk808 *rk808 = dev_get_drvdata(pdev->dev.parent);
413 struct rk808_rtc *rk808_rtc;
414 struct device_node *np;
415 int ret;
416
417 switch (rk808->variant) {
418 case RK805_ID:
419 case RK808_ID:
420 case RK816_ID:
421 case RK818_ID:
422 np = of_get_child_by_name(pdev->dev.parent->of_node, "rtc");
423 if (np && !of_device_is_available(np)) {
424 dev_info(&pdev->dev, "device is disabled\n");
425 return -EINVAL;
426 }
427 break;
428 default:
429 break;
430 }
431
432 rk808_rtc = devm_kzalloc(&pdev->dev, sizeof(*rk808_rtc), GFP_KERNEL);
433 if (rk808_rtc == NULL)
434 return -ENOMEM;
435
436 switch (rk808->variant) {
437 case RK808_ID:
438 case RK818_ID:
439 rk808_rtc->creg = &rk808_creg;
440 rk808_rtc->flag |= RTC_NEED_TRANSITIONS;
441 break;
442 case RK805_ID:
443 case RK816_ID:
444 rk808_rtc->creg = &rk808_creg;
445 break;
446 case RK809_ID:
447 case RK817_ID:
448 rk808_rtc->creg = &rk817_creg;
449 break;
450 default:
451 rk808_rtc->creg = &rk808_creg;
452 break;
453 }
454 platform_set_drvdata(pdev, rk808_rtc);
455 rk808_rtc->rk808 = rk808;
456
457 /* start rtc running by default, and use shadowed timer. */
458 ret = regmap_update_bits(rk808->regmap, rk808_rtc->creg->ctrl_reg,
459 BIT_RTC_CTRL_REG_STOP_RTC_M |
460 BIT_RTC_CTRL_REG_RTC_READSEL_M,
461 BIT_RTC_CTRL_REG_RTC_READSEL_M);
462 if (ret) {
463 dev_err(&pdev->dev,
464 "Failed to update RTC control: %d\n", ret);
465 return ret;
466 }
467
468 ret = regmap_write(rk808->regmap, rk808_rtc->creg->status_reg,
469 RTC_STATUS_MASK);
470 if (ret) {
471 dev_err(&pdev->dev,
472 "Failed to write RTC status: %d\n", ret);
473 return ret;
474 }
475
476 device_init_wakeup(&pdev->dev, 1);
477
478 rk808_rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
479 if (IS_ERR(rk808_rtc->rtc))
480 return PTR_ERR(rk808_rtc->rtc);
481
482 rk808_rtc->rtc->ops = &rk808_rtc_ops;
483
484 rk808_rtc->irq = platform_get_irq(pdev, 0);
485 if (rk808_rtc->irq < 0)
486 return rk808_rtc->irq;
487
488 /* request alarm irq of rk808 */
489 ret = devm_request_threaded_irq(&pdev->dev, rk808_rtc->irq, NULL,
490 rk808_alarm_irq, 0,
491 "RTC alarm", rk808_rtc);
492 if (ret) {
493 dev_err(&pdev->dev, "Failed to request alarm IRQ %d: %d\n",
494 rk808_rtc->irq, ret);
495 return ret;
496 }
497
498 return rtc_register_device(rk808_rtc->rtc);
499 }
500
501 static struct platform_driver rk808_rtc_driver = {
502 .probe = rk808_rtc_probe,
503 .driver = {
504 .name = "rk808-rtc",
505 .pm = &rk808_rtc_pm_ops,
506 },
507 };
508
509 module_platform_driver(rk808_rtc_driver);
510
511 MODULE_DESCRIPTION("RTC driver for the rk808 series PMICs");
512 MODULE_AUTHOR("Chris Zhong <zyw@rock-chips.com>");
513 MODULE_AUTHOR("Zhang Qing <zhangqing@rock-chips.com>");
514 MODULE_LICENSE("GPL");
515 MODULE_ALIAS("platform:rk808-rtc");
516