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1/*
2 * An RTC driver for Allwinner A31/A23
3 *
4 * Copyright (c) 2014, Chen-Yu Tsai <wens@csie.org>
5 *
6 * based on rtc-sunxi.c
7 *
8 * An RTC driver for Allwinner A10/A20
9 *
10 * Copyright (c) 2013, Carlo Caione <carlo.caione@gmail.com>
11 *
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 2 of the License, or
15 * (at your option) any later version.
16 *
17 * This program is distributed in the hope that it will be useful, but WITHOUT
18 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
19 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
20 * more details.
21 */
22
23#include <linux/delay.h>
24#include <linux/err.h>
25#include <linux/fs.h>
26#include <linux/init.h>
27#include <linux/interrupt.h>
28#include <linux/io.h>
29#include <linux/kernel.h>
30#include <linux/module.h>
31#include <linux/of.h>
32#include <linux/of_address.h>
33#include <linux/of_device.h>
34#include <linux/platform_device.h>
35#include <linux/rtc.h>
36#include <linux/types.h>
37
38/* Control register */
39#define SUN6I_LOSC_CTRL 0x0000
40#define SUN6I_LOSC_CTRL_KEY (0x16aa << 16)
41#define SUN6I_LOSC_CTRL_ALM_DHMS_ACC BIT(9)
42#define SUN6I_LOSC_CTRL_RTC_HMS_ACC BIT(8)
43#define SUN6I_LOSC_CTRL_RTC_YMD_ACC BIT(7)
44#define SUN6I_LOSC_CTRL_EXT_OSC BIT(0)
45#define SUN6I_LOSC_CTRL_ACC_MASK GENMASK(9, 7)
46
47/* RTC */
48#define SUN6I_RTC_YMD 0x0010
49#define SUN6I_RTC_HMS 0x0014
50
51/* Alarm 0 (counter) */
52#define SUN6I_ALRM_COUNTER 0x0020
53#define SUN6I_ALRM_CUR_VAL 0x0024
54#define SUN6I_ALRM_EN 0x0028
55#define SUN6I_ALRM_EN_CNT_EN BIT(0)
56#define SUN6I_ALRM_IRQ_EN 0x002c
57#define SUN6I_ALRM_IRQ_EN_CNT_IRQ_EN BIT(0)
58#define SUN6I_ALRM_IRQ_STA 0x0030
59#define SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND BIT(0)
60
61/* Alarm 1 (wall clock) */
62#define SUN6I_ALRM1_EN 0x0044
63#define SUN6I_ALRM1_IRQ_EN 0x0048
64#define SUN6I_ALRM1_IRQ_STA 0x004c
65#define SUN6I_ALRM1_IRQ_STA_WEEK_IRQ_PEND BIT(0)
66
67/* Alarm config */
68#define SUN6I_ALARM_CONFIG 0x0050
69#define SUN6I_ALARM_CONFIG_WAKEUP BIT(0)
70
71/*
72 * Get date values
73 */
74#define SUN6I_DATE_GET_DAY_VALUE(x) ((x) & 0x0000001f)
75#define SUN6I_DATE_GET_MON_VALUE(x) (((x) & 0x00000f00) >> 8)
76#define SUN6I_DATE_GET_YEAR_VALUE(x) (((x) & 0x003f0000) >> 16)
77#define SUN6I_LEAP_GET_VALUE(x) (((x) & 0x00400000) >> 22)
78
79/*
80 * Get time values
81 */
82#define SUN6I_TIME_GET_SEC_VALUE(x) ((x) & 0x0000003f)
83#define SUN6I_TIME_GET_MIN_VALUE(x) (((x) & 0x00003f00) >> 8)
84#define SUN6I_TIME_GET_HOUR_VALUE(x) (((x) & 0x001f0000) >> 16)
85
86/*
87 * Set date values
88 */
89#define SUN6I_DATE_SET_DAY_VALUE(x) ((x) & 0x0000001f)
90#define SUN6I_DATE_SET_MON_VALUE(x) ((x) << 8 & 0x00000f00)
91#define SUN6I_DATE_SET_YEAR_VALUE(x) ((x) << 16 & 0x003f0000)
92#define SUN6I_LEAP_SET_VALUE(x) ((x) << 22 & 0x00400000)
93
94/*
95 * Set time values
96 */
97#define SUN6I_TIME_SET_SEC_VALUE(x) ((x) & 0x0000003f)
98#define SUN6I_TIME_SET_MIN_VALUE(x) ((x) << 8 & 0x00003f00)
99#define SUN6I_TIME_SET_HOUR_VALUE(x) ((x) << 16 & 0x001f0000)
100
101/*
102 * The year parameter passed to the driver is usually an offset relative to
103 * the year 1900. This macro is used to convert this offset to another one
104 * relative to the minimum year allowed by the hardware.
105 *
106 * The year range is 1970 - 2033. This range is selected to match Allwinner's
107 * driver, even though it is somewhat limited.
108 */
109#define SUN6I_YEAR_MIN 1970
110#define SUN6I_YEAR_MAX 2033
111#define SUN6I_YEAR_OFF (SUN6I_YEAR_MIN - 1900)
112
113struct sun6i_rtc_dev {
114 struct rtc_device *rtc;
115 struct device *dev;
116 void __iomem *base;
117 int irq;
118 unsigned long alarm;
119
120 spinlock_t lock;
121};
122
123static irqreturn_t sun6i_rtc_alarmirq(int irq, void *id)
124{
125 struct sun6i_rtc_dev *chip = (struct sun6i_rtc_dev *) id;
126 irqreturn_t ret = IRQ_NONE;
127 u32 val;
128
129 spin_lock(&chip->lock);
130 val = readl(chip->base + SUN6I_ALRM_IRQ_STA);
131
132 if (val & SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND) {
133 val |= SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND;
134 writel(val, chip->base + SUN6I_ALRM_IRQ_STA);
135
136 rtc_update_irq(chip->rtc, 1, RTC_AF | RTC_IRQF);
137
138 ret = IRQ_HANDLED;
139 }
140 spin_unlock(&chip->lock);
141
142 return ret;
143}
144
145static void sun6i_rtc_setaie(int to, struct sun6i_rtc_dev *chip)
146{
147 u32 alrm_val = 0;
148 u32 alrm_irq_val = 0;
149 u32 alrm_wake_val = 0;
150 unsigned long flags;
151
152 if (to) {
153 alrm_val = SUN6I_ALRM_EN_CNT_EN;
154 alrm_irq_val = SUN6I_ALRM_IRQ_EN_CNT_IRQ_EN;
155 alrm_wake_val = SUN6I_ALARM_CONFIG_WAKEUP;
156 } else {
157 writel(SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND,
158 chip->base + SUN6I_ALRM_IRQ_STA);
159 }
160
161 spin_lock_irqsave(&chip->lock, flags);
162 writel(alrm_val, chip->base + SUN6I_ALRM_EN);
163 writel(alrm_irq_val, chip->base + SUN6I_ALRM_IRQ_EN);
164 writel(alrm_wake_val, chip->base + SUN6I_ALARM_CONFIG);
165 spin_unlock_irqrestore(&chip->lock, flags);
166}
167
168static int sun6i_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
169{
170 struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
171 u32 date, time;
172
173 /*
174 * read again in case it changes
175 */
176 do {
177 date = readl(chip->base + SUN6I_RTC_YMD);
178 time = readl(chip->base + SUN6I_RTC_HMS);
179 } while ((date != readl(chip->base + SUN6I_RTC_YMD)) ||
180 (time != readl(chip->base + SUN6I_RTC_HMS)));
181
182 rtc_tm->tm_sec = SUN6I_TIME_GET_SEC_VALUE(time);
183 rtc_tm->tm_min = SUN6I_TIME_GET_MIN_VALUE(time);
184 rtc_tm->tm_hour = SUN6I_TIME_GET_HOUR_VALUE(time);
185
186 rtc_tm->tm_mday = SUN6I_DATE_GET_DAY_VALUE(date);
187 rtc_tm->tm_mon = SUN6I_DATE_GET_MON_VALUE(date);
188 rtc_tm->tm_year = SUN6I_DATE_GET_YEAR_VALUE(date);
189
190 rtc_tm->tm_mon -= 1;
191
192 /*
193 * switch from (data_year->min)-relative offset to
194 * a (1900)-relative one
195 */
196 rtc_tm->tm_year += SUN6I_YEAR_OFF;
197
198 return rtc_valid_tm(rtc_tm);
199}
200
201static int sun6i_rtc_getalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
202{
203 struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
204 unsigned long flags;
205 u32 alrm_st;
206 u32 alrm_en;
207
208 spin_lock_irqsave(&chip->lock, flags);
209 alrm_en = readl(chip->base + SUN6I_ALRM_IRQ_EN);
210 alrm_st = readl(chip->base + SUN6I_ALRM_IRQ_STA);
211 spin_unlock_irqrestore(&chip->lock, flags);
212
213 wkalrm->enabled = !!(alrm_en & SUN6I_ALRM_EN_CNT_EN);
214 wkalrm->pending = !!(alrm_st & SUN6I_ALRM_EN_CNT_EN);
215 rtc_time_to_tm(chip->alarm, &wkalrm->time);
216
217 return 0;
218}
219
220static int sun6i_rtc_setalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
221{
222 struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
223 struct rtc_time *alrm_tm = &wkalrm->time;
224 struct rtc_time tm_now;
225 unsigned long time_now = 0;
226 unsigned long time_set = 0;
227 unsigned long time_gap = 0;
228 int ret = 0;
229
230 ret = sun6i_rtc_gettime(dev, &tm_now);
231 if (ret < 0) {
232 dev_err(dev, "Error in getting time\n");
233 return -EINVAL;
234 }
235
236 rtc_tm_to_time(alrm_tm, &time_set);
237 rtc_tm_to_time(&tm_now, &time_now);
238 if (time_set <= time_now) {
239 dev_err(dev, "Date to set in the past\n");
240 return -EINVAL;
241 }
242
243 time_gap = time_set - time_now;
244
245 if (time_gap > U32_MAX) {
246 dev_err(dev, "Date too far in the future\n");
247 return -EINVAL;
248 }
249
250 sun6i_rtc_setaie(0, chip);
251 writel(0, chip->base + SUN6I_ALRM_COUNTER);
252 usleep_range(100, 300);
253
254 writel(time_gap, chip->base + SUN6I_ALRM_COUNTER);
255 chip->alarm = time_set;
256
257 sun6i_rtc_setaie(wkalrm->enabled, chip);
258
259 return 0;
260}
261
262static int sun6i_rtc_wait(struct sun6i_rtc_dev *chip, int offset,
263 unsigned int mask, unsigned int ms_timeout)
264{
265 const unsigned long timeout = jiffies + msecs_to_jiffies(ms_timeout);
266 u32 reg;
267
268 do {
269 reg = readl(chip->base + offset);
270 reg &= mask;
271
272 if (!reg)
273 return 0;
274
275 } while (time_before(jiffies, timeout));
276
277 return -ETIMEDOUT;
278}
279
280static int sun6i_rtc_settime(struct device *dev, struct rtc_time *rtc_tm)
281{
282 struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
283 u32 date = 0;
284 u32 time = 0;
285 int year;
286
287 year = rtc_tm->tm_year + 1900;
288 if (year < SUN6I_YEAR_MIN || year > SUN6I_YEAR_MAX) {
289 dev_err(dev, "rtc only supports year in range %d - %d\n",
290 SUN6I_YEAR_MIN, SUN6I_YEAR_MAX);
291 return -EINVAL;
292 }
293
294 rtc_tm->tm_year -= SUN6I_YEAR_OFF;
295 rtc_tm->tm_mon += 1;
296
297 date = SUN6I_DATE_SET_DAY_VALUE(rtc_tm->tm_mday) |
298 SUN6I_DATE_SET_MON_VALUE(rtc_tm->tm_mon) |
299 SUN6I_DATE_SET_YEAR_VALUE(rtc_tm->tm_year);
300
301 if (is_leap_year(year))
302 date |= SUN6I_LEAP_SET_VALUE(1);
303
304 time = SUN6I_TIME_SET_SEC_VALUE(rtc_tm->tm_sec) |
305 SUN6I_TIME_SET_MIN_VALUE(rtc_tm->tm_min) |
306 SUN6I_TIME_SET_HOUR_VALUE(rtc_tm->tm_hour);
307
308 /* Check whether registers are writable */
309 if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
310 SUN6I_LOSC_CTRL_ACC_MASK, 50)) {
311 dev_err(dev, "rtc is still busy.\n");
312 return -EBUSY;
313 }
314
315 writel(time, chip->base + SUN6I_RTC_HMS);
316
317 /*
318 * After writing the RTC HH-MM-SS register, the
319 * SUN6I_LOSC_CTRL_RTC_HMS_ACC bit is set and it will not
320 * be cleared until the real writing operation is finished
321 */
322
323 if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
324 SUN6I_LOSC_CTRL_RTC_HMS_ACC, 50)) {
325 dev_err(dev, "Failed to set rtc time.\n");
326 return -ETIMEDOUT;
327 }
328
329 writel(date, chip->base + SUN6I_RTC_YMD);
330
331 /*
332 * After writing the RTC YY-MM-DD register, the
333 * SUN6I_LOSC_CTRL_RTC_YMD_ACC bit is set and it will not
334 * be cleared until the real writing operation is finished
335 */
336
337 if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
338 SUN6I_LOSC_CTRL_RTC_YMD_ACC, 50)) {
339 dev_err(dev, "Failed to set rtc time.\n");
340 return -ETIMEDOUT;
341 }
342
343 return 0;
344}
345
346static int sun6i_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
347{
348 struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
349
350 if (!enabled)
351 sun6i_rtc_setaie(enabled, chip);
352
353 return 0;
354}
355
356static const struct rtc_class_ops sun6i_rtc_ops = {
357 .read_time = sun6i_rtc_gettime,
358 .set_time = sun6i_rtc_settime,
359 .read_alarm = sun6i_rtc_getalarm,
360 .set_alarm = sun6i_rtc_setalarm,
361 .alarm_irq_enable = sun6i_rtc_alarm_irq_enable
362};
363
364static int sun6i_rtc_probe(struct platform_device *pdev)
365{
366 struct sun6i_rtc_dev *chip;
367 struct resource *res;
368 int ret;
369
370 chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
371 if (!chip)
372 return -ENOMEM;
373 spin_lock_init(&chip->lock);
374
375 platform_set_drvdata(pdev, chip);
376 chip->dev = &pdev->dev;
377
378 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
379 chip->base = devm_ioremap_resource(&pdev->dev, res);
380 if (IS_ERR(chip->base))
381 return PTR_ERR(chip->base);
382
383 chip->irq = platform_get_irq(pdev, 0);
384 if (chip->irq < 0) {
385 dev_err(&pdev->dev, "No IRQ resource\n");
386 return chip->irq;
387 }
388
389 ret = devm_request_irq(&pdev->dev, chip->irq, sun6i_rtc_alarmirq,
390 0, dev_name(&pdev->dev), chip);
391 if (ret) {
392 dev_err(&pdev->dev, "Could not request IRQ\n");
393 return ret;
394 }
395
396 /* clear the alarm counter value */
397 writel(0, chip->base + SUN6I_ALRM_COUNTER);
398
399 /* disable counter alarm */
400 writel(0, chip->base + SUN6I_ALRM_EN);
401
402 /* disable counter alarm interrupt */
403 writel(0, chip->base + SUN6I_ALRM_IRQ_EN);
404
405 /* disable week alarm */
406 writel(0, chip->base + SUN6I_ALRM1_EN);
407
408 /* disable week alarm interrupt */
409 writel(0, chip->base + SUN6I_ALRM1_IRQ_EN);
410
411 /* clear counter alarm pending interrupts */
412 writel(SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND,
413 chip->base + SUN6I_ALRM_IRQ_STA);
414
415 /* clear week alarm pending interrupts */
416 writel(SUN6I_ALRM1_IRQ_STA_WEEK_IRQ_PEND,
417 chip->base + SUN6I_ALRM1_IRQ_STA);
418
419 /* disable alarm wakeup */
420 writel(0, chip->base + SUN6I_ALARM_CONFIG);
421
422 /* switch to the external, more precise, oscillator */
423 writel(SUN6I_LOSC_CTRL_KEY | SUN6I_LOSC_CTRL_EXT_OSC,
424 chip->base + SUN6I_LOSC_CTRL);
425
426 chip->rtc = rtc_device_register("rtc-sun6i", &pdev->dev,
427 &sun6i_rtc_ops, THIS_MODULE);
428 if (IS_ERR(chip->rtc)) {
429 dev_err(&pdev->dev, "unable to register device\n");
430 return PTR_ERR(chip->rtc);
431 }
432
433 dev_info(&pdev->dev, "RTC enabled\n");
434
435 return 0;
436}
437
438static int sun6i_rtc_remove(struct platform_device *pdev)
439{
440 struct sun6i_rtc_dev *chip = platform_get_drvdata(pdev);
441
442 rtc_device_unregister(chip->rtc);
443
444 return 0;
445}
446
447static const struct of_device_id sun6i_rtc_dt_ids[] = {
448 { .compatible = "allwinner,sun6i-a31-rtc" },
449 { /* sentinel */ },
450};
451MODULE_DEVICE_TABLE(of, sun6i_rtc_dt_ids);
452
453static struct platform_driver sun6i_rtc_driver = {
454 .probe = sun6i_rtc_probe,
455 .remove = sun6i_rtc_remove,
456 .driver = {
457 .name = "sun6i-rtc",
458 .of_match_table = sun6i_rtc_dt_ids,
459 },
460};
461builtin_platform_driver(sun6i_rtc_driver);