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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * An RTC driver for Allwinner A10/A20
4 *
5 * Copyright (c) 2013, Carlo Caione <[email protected]>
6 */
7
8#include <linux/delay.h>
9#include <linux/err.h>
10#include <linux/fs.h>
11#include <linux/init.h>
12#include <linux/interrupt.h>
13#include <linux/io.h>
14#include <linux/kernel.h>
15#include <linux/module.h>
16#include <linux/of.h>
17#include <linux/platform_device.h>
18#include <linux/rtc.h>
19#include <linux/types.h>
20
21#define SUNXI_LOSC_CTRL 0x0000
22#define SUNXI_LOSC_CTRL_RTC_HMS_ACC BIT(8)
23#define SUNXI_LOSC_CTRL_RTC_YMD_ACC BIT(7)
24
25#define SUNXI_RTC_YMD 0x0004
26
27#define SUNXI_RTC_HMS 0x0008
28
29#define SUNXI_ALRM_DHMS 0x000c
30
31#define SUNXI_ALRM_EN 0x0014
32#define SUNXI_ALRM_EN_CNT_EN BIT(8)
33
34#define SUNXI_ALRM_IRQ_EN 0x0018
35#define SUNXI_ALRM_IRQ_EN_CNT_IRQ_EN BIT(0)
36
37#define SUNXI_ALRM_IRQ_STA 0x001c
38#define SUNXI_ALRM_IRQ_STA_CNT_IRQ_PEND BIT(0)
39
40#define SUNXI_MASK_DH 0x0000001f
41#define SUNXI_MASK_SM 0x0000003f
42#define SUNXI_MASK_M 0x0000000f
43#define SUNXI_MASK_LY 0x00000001
44#define SUNXI_MASK_D 0x00000ffe
45#define SUNXI_MASK_M 0x0000000f
46
47#define SUNXI_GET(x, mask, shift) (((x) & ((mask) << (shift))) \
48 >> (shift))
49
50#define SUNXI_SET(x, mask, shift) (((x) & (mask)) << (shift))
51
52/*
53 * Get date values
54 */
55#define SUNXI_DATE_GET_DAY_VALUE(x) SUNXI_GET(x, SUNXI_MASK_DH, 0)
56#define SUNXI_DATE_GET_MON_VALUE(x) SUNXI_GET(x, SUNXI_MASK_M, 8)
57#define SUNXI_DATE_GET_YEAR_VALUE(x, mask) SUNXI_GET(x, mask, 16)
58
59/*
60 * Get time values
61 */
62#define SUNXI_TIME_GET_SEC_VALUE(x) SUNXI_GET(x, SUNXI_MASK_SM, 0)
63#define SUNXI_TIME_GET_MIN_VALUE(x) SUNXI_GET(x, SUNXI_MASK_SM, 8)
64#define SUNXI_TIME_GET_HOUR_VALUE(x) SUNXI_GET(x, SUNXI_MASK_DH, 16)
65
66/*
67 * Get alarm values
68 */
69#define SUNXI_ALRM_GET_SEC_VALUE(x) SUNXI_GET(x, SUNXI_MASK_SM, 0)
70#define SUNXI_ALRM_GET_MIN_VALUE(x) SUNXI_GET(x, SUNXI_MASK_SM, 8)
71#define SUNXI_ALRM_GET_HOUR_VALUE(x) SUNXI_GET(x, SUNXI_MASK_DH, 16)
72
73/*
74 * Set date values
75 */
76#define SUNXI_DATE_SET_DAY_VALUE(x) SUNXI_DATE_GET_DAY_VALUE(x)
77#define SUNXI_DATE_SET_MON_VALUE(x) SUNXI_SET(x, SUNXI_MASK_M, 8)
78#define SUNXI_DATE_SET_YEAR_VALUE(x, mask) SUNXI_SET(x, mask, 16)
79#define SUNXI_LEAP_SET_VALUE(x, shift) SUNXI_SET(x, SUNXI_MASK_LY, shift)
80
81/*
82 * Set time values
83 */
84#define SUNXI_TIME_SET_SEC_VALUE(x) SUNXI_TIME_GET_SEC_VALUE(x)
85#define SUNXI_TIME_SET_MIN_VALUE(x) SUNXI_SET(x, SUNXI_MASK_SM, 8)
86#define SUNXI_TIME_SET_HOUR_VALUE(x) SUNXI_SET(x, SUNXI_MASK_DH, 16)
87
88/*
89 * Set alarm values
90 */
91#define SUNXI_ALRM_SET_SEC_VALUE(x) SUNXI_ALRM_GET_SEC_VALUE(x)
92#define SUNXI_ALRM_SET_MIN_VALUE(x) SUNXI_SET(x, SUNXI_MASK_SM, 8)
93#define SUNXI_ALRM_SET_HOUR_VALUE(x) SUNXI_SET(x, SUNXI_MASK_DH, 16)
94#define SUNXI_ALRM_SET_DAY_VALUE(x) SUNXI_SET(x, SUNXI_MASK_D, 21)
95
96/*
97 * Time unit conversions
98 */
99#define SEC_IN_MIN 60
100#define SEC_IN_HOUR (60 * SEC_IN_MIN)
101#define SEC_IN_DAY (24 * SEC_IN_HOUR)
102
103/*
104 * The year parameter passed to the driver is usually an offset relative to
105 * the year 1900. This macro is used to convert this offset to another one
106 * relative to the minimum year allowed by the hardware.
107 */
108#define SUNXI_YEAR_OFF(x) ((x)->min - 1900)
109
110/*
111 * min and max year are arbitrary set considering the limited range of the
112 * hardware register field
113 */
114struct sunxi_rtc_data_year {
115 unsigned int min; /* min year allowed */
116 unsigned int max; /* max year allowed */
117 unsigned int mask; /* mask for the year field */
118 unsigned char leap_shift; /* bit shift to get the leap year */
119};
120
121static const struct sunxi_rtc_data_year data_year_param[] = {
122 [0] = {
123 .min = 2010,
124 .max = 2073,
125 .mask = 0x3f,
126 .leap_shift = 22,
127 },
128 [1] = {
129 .min = 1970,
130 .max = 2225,
131 .mask = 0xff,
132 .leap_shift = 24,
133 },
134};
135
136struct sunxi_rtc_dev {
137 struct rtc_device *rtc;
138 struct device *dev;
139 const struct sunxi_rtc_data_year *data_year;
140 void __iomem *base;
141 int irq;
142};
143
144static irqreturn_t sunxi_rtc_alarmirq(int irq, void *id)
145{
146 struct sunxi_rtc_dev *chip = (struct sunxi_rtc_dev *) id;
147 u32 val;
148
149 val = readl(chip->base + SUNXI_ALRM_IRQ_STA);
150
151 if (val & SUNXI_ALRM_IRQ_STA_CNT_IRQ_PEND) {
152 val |= SUNXI_ALRM_IRQ_STA_CNT_IRQ_PEND;
153 writel(val, chip->base + SUNXI_ALRM_IRQ_STA);
154
155 rtc_update_irq(chip->rtc, 1, RTC_AF | RTC_IRQF);
156
157 return IRQ_HANDLED;
158 }
159
160 return IRQ_NONE;
161}
162
163static void sunxi_rtc_setaie(unsigned int to, struct sunxi_rtc_dev *chip)
164{
165 u32 alrm_val = 0;
166 u32 alrm_irq_val = 0;
167
168 if (to) {
169 alrm_val = readl(chip->base + SUNXI_ALRM_EN);
170 alrm_val |= SUNXI_ALRM_EN_CNT_EN;
171
172 alrm_irq_val = readl(chip->base + SUNXI_ALRM_IRQ_EN);
173 alrm_irq_val |= SUNXI_ALRM_IRQ_EN_CNT_IRQ_EN;
174 } else {
175 writel(SUNXI_ALRM_IRQ_STA_CNT_IRQ_PEND,
176 chip->base + SUNXI_ALRM_IRQ_STA);
177 }
178
179 writel(alrm_val, chip->base + SUNXI_ALRM_EN);
180 writel(alrm_irq_val, chip->base + SUNXI_ALRM_IRQ_EN);
181}
182
183static int sunxi_rtc_getalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
184{
185 struct sunxi_rtc_dev *chip = dev_get_drvdata(dev);
186 struct rtc_time *alrm_tm = &wkalrm->time;
187 u32 alrm;
188 u32 alrm_en;
189 u32 date;
190
191 alrm = readl(chip->base + SUNXI_ALRM_DHMS);
192 date = readl(chip->base + SUNXI_RTC_YMD);
193
194 alrm_tm->tm_sec = SUNXI_ALRM_GET_SEC_VALUE(alrm);
195 alrm_tm->tm_min = SUNXI_ALRM_GET_MIN_VALUE(alrm);
196 alrm_tm->tm_hour = SUNXI_ALRM_GET_HOUR_VALUE(alrm);
197
198 alrm_tm->tm_mday = SUNXI_DATE_GET_DAY_VALUE(date);
199 alrm_tm->tm_mon = SUNXI_DATE_GET_MON_VALUE(date);
200 alrm_tm->tm_year = SUNXI_DATE_GET_YEAR_VALUE(date,
201 chip->data_year->mask);
202
203 alrm_tm->tm_mon -= 1;
204
205 /*
206 * switch from (data_year->min)-relative offset to
207 * a (1900)-relative one
208 */
209 alrm_tm->tm_year += SUNXI_YEAR_OFF(chip->data_year);
210
211 alrm_en = readl(chip->base + SUNXI_ALRM_IRQ_EN);
212 if (alrm_en & SUNXI_ALRM_EN_CNT_EN)
213 wkalrm->enabled = 1;
214
215 return 0;
216}
217
218static int sunxi_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
219{
220 struct sunxi_rtc_dev *chip = dev_get_drvdata(dev);
221 u32 date, time;
222
223 /*
224 * read again in case it changes
225 */
226 do {
227 date = readl(chip->base + SUNXI_RTC_YMD);
228 time = readl(chip->base + SUNXI_RTC_HMS);
229 } while ((date != readl(chip->base + SUNXI_RTC_YMD)) ||
230 (time != readl(chip->base + SUNXI_RTC_HMS)));
231
232 rtc_tm->tm_sec = SUNXI_TIME_GET_SEC_VALUE(time);
233 rtc_tm->tm_min = SUNXI_TIME_GET_MIN_VALUE(time);
234 rtc_tm->tm_hour = SUNXI_TIME_GET_HOUR_VALUE(time);
235
236 rtc_tm->tm_mday = SUNXI_DATE_GET_DAY_VALUE(date);
237 rtc_tm->tm_mon = SUNXI_DATE_GET_MON_VALUE(date);
238 rtc_tm->tm_year = SUNXI_DATE_GET_YEAR_VALUE(date,
239 chip->data_year->mask);
240
241 rtc_tm->tm_mon -= 1;
242
243 /*
244 * switch from (data_year->min)-relative offset to
245 * a (1900)-relative one
246 */
247 rtc_tm->tm_year += SUNXI_YEAR_OFF(chip->data_year);
248
249 return 0;
250}
251
252static int sunxi_rtc_setalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
253{
254 struct sunxi_rtc_dev *chip = dev_get_drvdata(dev);
255 struct rtc_time *alrm_tm = &wkalrm->time;
256 struct rtc_time tm_now;
257 u32 alrm;
258 time64_t diff;
259 unsigned long time_gap;
260 unsigned long time_gap_day;
261 unsigned long time_gap_hour;
262 unsigned long time_gap_min;
263 int ret;
264
265 ret = sunxi_rtc_gettime(dev, &tm_now);
266 if (ret < 0) {
267 dev_err(dev, "Error in getting time\n");
268 return -EINVAL;
269 }
270
271 diff = rtc_tm_sub(alrm_tm, &tm_now);
272 if (diff <= 0) {
273 dev_err(dev, "Date to set in the past\n");
274 return -EINVAL;
275 }
276
277 if (diff > 255 * SEC_IN_DAY) {
278 dev_err(dev, "Day must be in the range 0 - 255\n");
279 return -EINVAL;
280 }
281
282 time_gap = diff;
283 time_gap_day = time_gap / SEC_IN_DAY;
284 time_gap -= time_gap_day * SEC_IN_DAY;
285 time_gap_hour = time_gap / SEC_IN_HOUR;
286 time_gap -= time_gap_hour * SEC_IN_HOUR;
287 time_gap_min = time_gap / SEC_IN_MIN;
288 time_gap -= time_gap_min * SEC_IN_MIN;
289
290 sunxi_rtc_setaie(0, chip);
291 writel(0, chip->base + SUNXI_ALRM_DHMS);
292 usleep_range(100, 300);
293
294 alrm = SUNXI_ALRM_SET_SEC_VALUE(time_gap) |
295 SUNXI_ALRM_SET_MIN_VALUE(time_gap_min) |
296 SUNXI_ALRM_SET_HOUR_VALUE(time_gap_hour) |
297 SUNXI_ALRM_SET_DAY_VALUE(time_gap_day);
298 writel(alrm, chip->base + SUNXI_ALRM_DHMS);
299
300 writel(0, chip->base + SUNXI_ALRM_IRQ_EN);
301 writel(SUNXI_ALRM_IRQ_EN_CNT_IRQ_EN, chip->base + SUNXI_ALRM_IRQ_EN);
302
303 sunxi_rtc_setaie(wkalrm->enabled, chip);
304
305 return 0;
306}
307
308static int sunxi_rtc_wait(struct sunxi_rtc_dev *chip, int offset,
309 unsigned int mask, unsigned int ms_timeout)
310{
311 const unsigned long timeout = jiffies + msecs_to_jiffies(ms_timeout);
312 u32 reg;
313
314 do {
315 reg = readl(chip->base + offset);
316 reg &= mask;
317
318 if (reg == mask)
319 return 0;
320
321 } while (time_before(jiffies, timeout));
322
323 return -ETIMEDOUT;
324}
325
326static int sunxi_rtc_settime(struct device *dev, struct rtc_time *rtc_tm)
327{
328 struct sunxi_rtc_dev *chip = dev_get_drvdata(dev);
329 u32 date = 0;
330 u32 time = 0;
331 unsigned int year;
332
333 /*
334 * the input rtc_tm->tm_year is the offset relative to 1900. We use
335 * the SUNXI_YEAR_OFF macro to rebase it with respect to the min year
336 * allowed by the hardware
337 */
338
339 year = rtc_tm->tm_year + 1900;
340 if (year < chip->data_year->min || year > chip->data_year->max) {
341 dev_err(dev, "rtc only supports year in range %u - %u\n",
342 chip->data_year->min, chip->data_year->max);
343 return -EINVAL;
344 }
345
346 rtc_tm->tm_year -= SUNXI_YEAR_OFF(chip->data_year);
347 rtc_tm->tm_mon += 1;
348
349 date = SUNXI_DATE_SET_DAY_VALUE(rtc_tm->tm_mday) |
350 SUNXI_DATE_SET_MON_VALUE(rtc_tm->tm_mon) |
351 SUNXI_DATE_SET_YEAR_VALUE(rtc_tm->tm_year,
352 chip->data_year->mask);
353
354 if (is_leap_year(year))
355 date |= SUNXI_LEAP_SET_VALUE(1, chip->data_year->leap_shift);
356
357 time = SUNXI_TIME_SET_SEC_VALUE(rtc_tm->tm_sec) |
358 SUNXI_TIME_SET_MIN_VALUE(rtc_tm->tm_min) |
359 SUNXI_TIME_SET_HOUR_VALUE(rtc_tm->tm_hour);
360
361 writel(0, chip->base + SUNXI_RTC_HMS);
362 writel(0, chip->base + SUNXI_RTC_YMD);
363
364 writel(time, chip->base + SUNXI_RTC_HMS);
365
366 /*
367 * After writing the RTC HH-MM-SS register, the
368 * SUNXI_LOSC_CTRL_RTC_HMS_ACC bit is set and it will not
369 * be cleared until the real writing operation is finished
370 */
371
372 if (sunxi_rtc_wait(chip, SUNXI_LOSC_CTRL,
373 SUNXI_LOSC_CTRL_RTC_HMS_ACC, 50)) {
374 dev_err(dev, "Failed to set rtc time.\n");
375 return -1;
376 }
377
378 writel(date, chip->base + SUNXI_RTC_YMD);
379
380 /*
381 * After writing the RTC YY-MM-DD register, the
382 * SUNXI_LOSC_CTRL_RTC_YMD_ACC bit is set and it will not
383 * be cleared until the real writing operation is finished
384 */
385
386 if (sunxi_rtc_wait(chip, SUNXI_LOSC_CTRL,
387 SUNXI_LOSC_CTRL_RTC_YMD_ACC, 50)) {
388 dev_err(dev, "Failed to set rtc time.\n");
389 return -1;
390 }
391
392 return 0;
393}
394
395static int sunxi_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
396{
397 struct sunxi_rtc_dev *chip = dev_get_drvdata(dev);
398
399 if (!enabled)
400 sunxi_rtc_setaie(enabled, chip);
401
402 return 0;
403}
404
405static const struct rtc_class_ops sunxi_rtc_ops = {
406 .read_time = sunxi_rtc_gettime,
407 .set_time = sunxi_rtc_settime,
408 .read_alarm = sunxi_rtc_getalarm,
409 .set_alarm = sunxi_rtc_setalarm,
410 .alarm_irq_enable = sunxi_rtc_alarm_irq_enable
411};
412
413static const struct of_device_id sunxi_rtc_dt_ids[] = {
414 { .compatible = "allwinner,sun4i-a10-rtc", .data = &data_year_param[0] },
415 { .compatible = "allwinner,sun7i-a20-rtc", .data = &data_year_param[1] },
416 { /* sentinel */ },
417};
418MODULE_DEVICE_TABLE(of, sunxi_rtc_dt_ids);
419
420static int sunxi_rtc_probe(struct platform_device *pdev)
421{
422 struct sunxi_rtc_dev *chip;
423 int ret;
424
425 chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
426 if (!chip)
427 return -ENOMEM;
428
429 platform_set_drvdata(pdev, chip);
430 chip->dev = &pdev->dev;
431
432 chip->rtc = devm_rtc_allocate_device(&pdev->dev);
433 if (IS_ERR(chip->rtc))
434 return PTR_ERR(chip->rtc);
435
436 chip->base = devm_platform_ioremap_resource(pdev, 0);
437 if (IS_ERR(chip->base))
438 return PTR_ERR(chip->base);
439
440 chip->irq = platform_get_irq(pdev, 0);
441 if (chip->irq < 0)
442 return chip->irq;
443 ret = devm_request_irq(&pdev->dev, chip->irq, sunxi_rtc_alarmirq,
444 0, dev_name(&pdev->dev), chip);
445 if (ret) {
446 dev_err(&pdev->dev, "Could not request IRQ\n");
447 return ret;
448 }
449
450 chip->data_year = of_device_get_match_data(&pdev->dev);
451 if (!chip->data_year) {
452 dev_err(&pdev->dev, "Unable to setup RTC data\n");
453 return -ENODEV;
454 }
455
456 /* clear the alarm count value */
457 writel(0, chip->base + SUNXI_ALRM_DHMS);
458
459 /* disable alarm, not generate irq pending */
460 writel(0, chip->base + SUNXI_ALRM_EN);
461
462 /* disable alarm week/cnt irq, unset to cpu */
463 writel(0, chip->base + SUNXI_ALRM_IRQ_EN);
464
465 /* clear alarm week/cnt irq pending */
466 writel(SUNXI_ALRM_IRQ_STA_CNT_IRQ_PEND, chip->base +
467 SUNXI_ALRM_IRQ_STA);
468
469 chip->rtc->ops = &sunxi_rtc_ops;
470
471 return devm_rtc_register_device(chip->rtc);
472}
473
474static struct platform_driver sunxi_rtc_driver = {
475 .probe = sunxi_rtc_probe,
476 .driver = {
477 .name = "sunxi-rtc",
478 .of_match_table = sunxi_rtc_dt_ids,
479 },
480};
481
482module_platform_driver(sunxi_rtc_driver);
483
484MODULE_DESCRIPTION("sunxi RTC driver");
485MODULE_AUTHOR("Carlo Caione <[email protected]>");
486MODULE_LICENSE("GPL");