1 /*
2  * An RTC driver for Allwinner A10/A20
3  *
4  * Copyright (c) 2013, Carlo Caione <carlo.caione@gmail.com>
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful, but WITHOUT
12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
14  * more details.
15  *
16  * You should have received a copy of the GNU General Public License along
17  * with this program; if not, write to the Free Software Foundation, Inc.,
18  * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
19  */
20 
21 #include <linux/delay.h>
22 #include <linux/err.h>
23 #include <linux/fs.h>
24 #include <linux/init.h>
25 #include <linux/interrupt.h>
26 #include <linux/io.h>
27 #include <linux/kernel.h>
28 #include <linux/module.h>
29 #include <linux/of.h>
30 #include <linux/of_address.h>
31 #include <linux/of_device.h>
32 #include <linux/platform_device.h>
33 #include <linux/rtc.h>
34 #include <linux/types.h>
35 
36 #define SUNXI_LOSC_CTRL				0x0000
37 #define SUNXI_LOSC_CTRL_RTC_HMS_ACC		BIT(8)
38 #define SUNXI_LOSC_CTRL_RTC_YMD_ACC		BIT(7)
39 
40 #define SUNXI_RTC_YMD				0x0004
41 
42 #define SUNXI_RTC_HMS				0x0008
43 
44 #define SUNXI_ALRM_DHMS				0x000c
45 
46 #define SUNXI_ALRM_EN				0x0014
47 #define SUNXI_ALRM_EN_CNT_EN			BIT(8)
48 
49 #define SUNXI_ALRM_IRQ_EN			0x0018
50 #define SUNXI_ALRM_IRQ_EN_CNT_IRQ_EN		BIT(0)
51 
52 #define SUNXI_ALRM_IRQ_STA			0x001c
53 #define SUNXI_ALRM_IRQ_STA_CNT_IRQ_PEND		BIT(0)
54 
55 #define SUNXI_MASK_DH				0x0000001f
56 #define SUNXI_MASK_SM				0x0000003f
57 #define SUNXI_MASK_M				0x0000000f
58 #define SUNXI_MASK_LY				0x00000001
59 #define SUNXI_MASK_D				0x00000ffe
60 #define SUNXI_MASK_M				0x0000000f
61 
62 #define SUNXI_GET(x, mask, shift)		(((x) & ((mask) << (shift))) \
63 							>> (shift))
64 
65 #define SUNXI_SET(x, mask, shift)		(((x) & (mask)) << (shift))
66 
67 /*
68  * Get date values
69  */
70 #define SUNXI_DATE_GET_DAY_VALUE(x)		SUNXI_GET(x, SUNXI_MASK_DH, 0)
71 #define SUNXI_DATE_GET_MON_VALUE(x)		SUNXI_GET(x, SUNXI_MASK_M, 8)
72 #define SUNXI_DATE_GET_YEAR_VALUE(x, mask)	SUNXI_GET(x, mask, 16)
73 
74 /*
75  * Get time values
76  */
77 #define SUNXI_TIME_GET_SEC_VALUE(x)		SUNXI_GET(x, SUNXI_MASK_SM, 0)
78 #define SUNXI_TIME_GET_MIN_VALUE(x)		SUNXI_GET(x, SUNXI_MASK_SM, 8)
79 #define SUNXI_TIME_GET_HOUR_VALUE(x)		SUNXI_GET(x, SUNXI_MASK_DH, 16)
80 
81 /*
82  * Get alarm values
83  */
84 #define SUNXI_ALRM_GET_SEC_VALUE(x)		SUNXI_GET(x, SUNXI_MASK_SM, 0)
85 #define SUNXI_ALRM_GET_MIN_VALUE(x)		SUNXI_GET(x, SUNXI_MASK_SM, 8)
86 #define SUNXI_ALRM_GET_HOUR_VALUE(x)		SUNXI_GET(x, SUNXI_MASK_DH, 16)
87 
88 /*
89  * Set date values
90  */
91 #define SUNXI_DATE_SET_DAY_VALUE(x)		SUNXI_DATE_GET_DAY_VALUE(x)
92 #define SUNXI_DATE_SET_MON_VALUE(x)		SUNXI_SET(x, SUNXI_MASK_M, 8)
93 #define SUNXI_DATE_SET_YEAR_VALUE(x, mask)	SUNXI_SET(x, mask, 16)
94 #define SUNXI_LEAP_SET_VALUE(x, shift)		SUNXI_SET(x, SUNXI_MASK_LY, shift)
95 
96 /*
97  * Set time values
98  */
99 #define SUNXI_TIME_SET_SEC_VALUE(x)		SUNXI_TIME_GET_SEC_VALUE(x)
100 #define SUNXI_TIME_SET_MIN_VALUE(x)		SUNXI_SET(x, SUNXI_MASK_SM, 8)
101 #define SUNXI_TIME_SET_HOUR_VALUE(x)		SUNXI_SET(x, SUNXI_MASK_DH, 16)
102 
103 /*
104  * Set alarm values
105  */
106 #define SUNXI_ALRM_SET_SEC_VALUE(x)		SUNXI_ALRM_GET_SEC_VALUE(x)
107 #define SUNXI_ALRM_SET_MIN_VALUE(x)		SUNXI_SET(x, SUNXI_MASK_SM, 8)
108 #define SUNXI_ALRM_SET_HOUR_VALUE(x)		SUNXI_SET(x, SUNXI_MASK_DH, 16)
109 #define SUNXI_ALRM_SET_DAY_VALUE(x)		SUNXI_SET(x, SUNXI_MASK_D, 21)
110 
111 /*
112  * Time unit conversions
113  */
114 #define SEC_IN_MIN				60
115 #define SEC_IN_HOUR				(60 * SEC_IN_MIN)
116 #define SEC_IN_DAY				(24 * SEC_IN_HOUR)
117 
118 /*
119  * The year parameter passed to the driver is usually an offset relative to
120  * the year 1900. This macro is used to convert this offset to another one
121  * relative to the minimum year allowed by the hardware.
122  */
123 #define SUNXI_YEAR_OFF(x)			((x)->min - 1900)
124 
125 /*
126  * min and max year are arbitrary set considering the limited range of the
127  * hardware register field
128  */
129 struct sunxi_rtc_data_year {
130 	unsigned int min;		/* min year allowed */
131 	unsigned int max;		/* max year allowed */
132 	unsigned int mask;		/* mask for the year field */
133 	unsigned char leap_shift;	/* bit shift to get the leap year */
134 };
135 
136 static const struct sunxi_rtc_data_year data_year_param[] = {
137 	[0] = {
138 		.min		= 2010,
139 		.max		= 2073,
140 		.mask		= 0x3f,
141 		.leap_shift	= 22,
142 	},
143 	[1] = {
144 		.min		= 1970,
145 		.max		= 2225,
146 		.mask		= 0xff,
147 		.leap_shift	= 24,
148 	},
149 };
150 
151 struct sunxi_rtc_dev {
152 	struct rtc_device *rtc;
153 	struct device *dev;
154 	const struct sunxi_rtc_data_year *data_year;
155 	void __iomem *base;
156 	int irq;
157 };
158 
sunxi_rtc_alarmirq(int irq,void * id)159 static irqreturn_t sunxi_rtc_alarmirq(int irq, void *id)
160 {
161 	struct sunxi_rtc_dev *chip = (struct sunxi_rtc_dev *) id;
162 	u32 val;
163 
164 	val = readl(chip->base + SUNXI_ALRM_IRQ_STA);
165 
166 	if (val & SUNXI_ALRM_IRQ_STA_CNT_IRQ_PEND) {
167 		val |= SUNXI_ALRM_IRQ_STA_CNT_IRQ_PEND;
168 		writel(val, chip->base + SUNXI_ALRM_IRQ_STA);
169 
170 		rtc_update_irq(chip->rtc, 1, RTC_AF | RTC_IRQF);
171 
172 		return IRQ_HANDLED;
173 	}
174 
175 	return IRQ_NONE;
176 }
177 
sunxi_rtc_setaie(unsigned int to,struct sunxi_rtc_dev * chip)178 static void sunxi_rtc_setaie(unsigned int to, struct sunxi_rtc_dev *chip)
179 {
180 	u32 alrm_val = 0;
181 	u32 alrm_irq_val = 0;
182 
183 	if (to) {
184 		alrm_val = readl(chip->base + SUNXI_ALRM_EN);
185 		alrm_val |= SUNXI_ALRM_EN_CNT_EN;
186 
187 		alrm_irq_val = readl(chip->base + SUNXI_ALRM_IRQ_EN);
188 		alrm_irq_val |= SUNXI_ALRM_IRQ_EN_CNT_IRQ_EN;
189 	} else {
190 		writel(SUNXI_ALRM_IRQ_STA_CNT_IRQ_PEND,
191 				chip->base + SUNXI_ALRM_IRQ_STA);
192 	}
193 
194 	writel(alrm_val, chip->base + SUNXI_ALRM_EN);
195 	writel(alrm_irq_val, chip->base + SUNXI_ALRM_IRQ_EN);
196 }
197 
sunxi_rtc_getalarm(struct device * dev,struct rtc_wkalrm * wkalrm)198 static int sunxi_rtc_getalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
199 {
200 	struct sunxi_rtc_dev *chip = dev_get_drvdata(dev);
201 	struct rtc_time *alrm_tm = &wkalrm->time;
202 	u32 alrm;
203 	u32 alrm_en;
204 	u32 date;
205 
206 	alrm = readl(chip->base + SUNXI_ALRM_DHMS);
207 	date = readl(chip->base + SUNXI_RTC_YMD);
208 
209 	alrm_tm->tm_sec = SUNXI_ALRM_GET_SEC_VALUE(alrm);
210 	alrm_tm->tm_min = SUNXI_ALRM_GET_MIN_VALUE(alrm);
211 	alrm_tm->tm_hour = SUNXI_ALRM_GET_HOUR_VALUE(alrm);
212 
213 	alrm_tm->tm_mday = SUNXI_DATE_GET_DAY_VALUE(date);
214 	alrm_tm->tm_mon = SUNXI_DATE_GET_MON_VALUE(date);
215 	alrm_tm->tm_year = SUNXI_DATE_GET_YEAR_VALUE(date,
216 			chip->data_year->mask);
217 
218 	alrm_tm->tm_mon -= 1;
219 
220 	/*
221 	 * switch from (data_year->min)-relative offset to
222 	 * a (1900)-relative one
223 	 */
224 	alrm_tm->tm_year += SUNXI_YEAR_OFF(chip->data_year);
225 
226 	alrm_en = readl(chip->base + SUNXI_ALRM_IRQ_EN);
227 	if (alrm_en & SUNXI_ALRM_EN_CNT_EN)
228 		wkalrm->enabled = 1;
229 
230 	return 0;
231 }
232 
sunxi_rtc_gettime(struct device * dev,struct rtc_time * rtc_tm)233 static int sunxi_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
234 {
235 	struct sunxi_rtc_dev *chip = dev_get_drvdata(dev);
236 	u32 date, time;
237 
238 	/*
239 	 * read again in case it changes
240 	 */
241 	do {
242 		date = readl(chip->base + SUNXI_RTC_YMD);
243 		time = readl(chip->base + SUNXI_RTC_HMS);
244 	} while ((date != readl(chip->base + SUNXI_RTC_YMD)) ||
245 		 (time != readl(chip->base + SUNXI_RTC_HMS)));
246 
247 	rtc_tm->tm_sec  = SUNXI_TIME_GET_SEC_VALUE(time);
248 	rtc_tm->tm_min  = SUNXI_TIME_GET_MIN_VALUE(time);
249 	rtc_tm->tm_hour = SUNXI_TIME_GET_HOUR_VALUE(time);
250 
251 	rtc_tm->tm_mday = SUNXI_DATE_GET_DAY_VALUE(date);
252 	rtc_tm->tm_mon  = SUNXI_DATE_GET_MON_VALUE(date);
253 	rtc_tm->tm_year = SUNXI_DATE_GET_YEAR_VALUE(date,
254 					chip->data_year->mask);
255 
256 	rtc_tm->tm_mon  -= 1;
257 
258 	/*
259 	 * switch from (data_year->min)-relative offset to
260 	 * a (1900)-relative one
261 	 */
262 	rtc_tm->tm_year += SUNXI_YEAR_OFF(chip->data_year);
263 
264 	return 0;
265 }
266 
sunxi_rtc_setalarm(struct device * dev,struct rtc_wkalrm * wkalrm)267 static int sunxi_rtc_setalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
268 {
269 	struct sunxi_rtc_dev *chip = dev_get_drvdata(dev);
270 	struct rtc_time *alrm_tm = &wkalrm->time;
271 	struct rtc_time tm_now;
272 	u32 alrm;
273 	time64_t diff;
274 	unsigned long time_gap;
275 	unsigned long time_gap_day;
276 	unsigned long time_gap_hour;
277 	unsigned long time_gap_min;
278 	int ret;
279 
280 	ret = sunxi_rtc_gettime(dev, &tm_now);
281 	if (ret < 0) {
282 		dev_err(dev, "Error in getting time\n");
283 		return -EINVAL;
284 	}
285 
286 	diff = rtc_tm_sub(alrm_tm, &tm_now);
287 	if (diff <= 0) {
288 		dev_err(dev, "Date to set in the past\n");
289 		return -EINVAL;
290 	}
291 
292 	if (diff > 255 * SEC_IN_DAY) {
293 		dev_err(dev, "Day must be in the range 0 - 255\n");
294 		return -EINVAL;
295 	}
296 
297 	time_gap = diff;
298 	time_gap_day = time_gap / SEC_IN_DAY;
299 	time_gap -= time_gap_day * SEC_IN_DAY;
300 	time_gap_hour = time_gap / SEC_IN_HOUR;
301 	time_gap -= time_gap_hour * SEC_IN_HOUR;
302 	time_gap_min = time_gap / SEC_IN_MIN;
303 	time_gap -= time_gap_min * SEC_IN_MIN;
304 
305 	sunxi_rtc_setaie(0, chip);
306 	writel(0, chip->base + SUNXI_ALRM_DHMS);
307 	usleep_range(100, 300);
308 
309 	alrm = SUNXI_ALRM_SET_SEC_VALUE(time_gap) |
310 		SUNXI_ALRM_SET_MIN_VALUE(time_gap_min) |
311 		SUNXI_ALRM_SET_HOUR_VALUE(time_gap_hour) |
312 		SUNXI_ALRM_SET_DAY_VALUE(time_gap_day);
313 	writel(alrm, chip->base + SUNXI_ALRM_DHMS);
314 
315 	writel(0, chip->base + SUNXI_ALRM_IRQ_EN);
316 	writel(SUNXI_ALRM_IRQ_EN_CNT_IRQ_EN, chip->base + SUNXI_ALRM_IRQ_EN);
317 
318 	sunxi_rtc_setaie(wkalrm->enabled, chip);
319 
320 	return 0;
321 }
322 
sunxi_rtc_wait(struct sunxi_rtc_dev * chip,int offset,unsigned int mask,unsigned int ms_timeout)323 static int sunxi_rtc_wait(struct sunxi_rtc_dev *chip, int offset,
324 			  unsigned int mask, unsigned int ms_timeout)
325 {
326 	const unsigned long timeout = jiffies + msecs_to_jiffies(ms_timeout);
327 	u32 reg;
328 
329 	do {
330 		reg = readl(chip->base + offset);
331 		reg &= mask;
332 
333 		if (reg == mask)
334 			return 0;
335 
336 	} while (time_before(jiffies, timeout));
337 
338 	return -ETIMEDOUT;
339 }
340 
sunxi_rtc_settime(struct device * dev,struct rtc_time * rtc_tm)341 static int sunxi_rtc_settime(struct device *dev, struct rtc_time *rtc_tm)
342 {
343 	struct sunxi_rtc_dev *chip = dev_get_drvdata(dev);
344 	u32 date = 0;
345 	u32 time = 0;
346 	unsigned int year;
347 
348 	/*
349 	 * the input rtc_tm->tm_year is the offset relative to 1900. We use
350 	 * the SUNXI_YEAR_OFF macro to rebase it with respect to the min year
351 	 * allowed by the hardware
352 	 */
353 
354 	year = rtc_tm->tm_year + 1900;
355 	if (year < chip->data_year->min || year > chip->data_year->max) {
356 		dev_err(dev, "rtc only supports year in range %u - %u\n",
357 			chip->data_year->min, chip->data_year->max);
358 		return -EINVAL;
359 	}
360 
361 	rtc_tm->tm_year -= SUNXI_YEAR_OFF(chip->data_year);
362 	rtc_tm->tm_mon += 1;
363 
364 	date = SUNXI_DATE_SET_DAY_VALUE(rtc_tm->tm_mday) |
365 		SUNXI_DATE_SET_MON_VALUE(rtc_tm->tm_mon)  |
366 		SUNXI_DATE_SET_YEAR_VALUE(rtc_tm->tm_year,
367 				chip->data_year->mask);
368 
369 	if (is_leap_year(year))
370 		date |= SUNXI_LEAP_SET_VALUE(1, chip->data_year->leap_shift);
371 
372 	time = SUNXI_TIME_SET_SEC_VALUE(rtc_tm->tm_sec)  |
373 		SUNXI_TIME_SET_MIN_VALUE(rtc_tm->tm_min)  |
374 		SUNXI_TIME_SET_HOUR_VALUE(rtc_tm->tm_hour);
375 
376 	writel(0, chip->base + SUNXI_RTC_HMS);
377 	writel(0, chip->base + SUNXI_RTC_YMD);
378 
379 	writel(time, chip->base + SUNXI_RTC_HMS);
380 
381 	/*
382 	 * After writing the RTC HH-MM-SS register, the
383 	 * SUNXI_LOSC_CTRL_RTC_HMS_ACC bit is set and it will not
384 	 * be cleared until the real writing operation is finished
385 	 */
386 
387 	if (sunxi_rtc_wait(chip, SUNXI_LOSC_CTRL,
388 				SUNXI_LOSC_CTRL_RTC_HMS_ACC, 50)) {
389 		dev_err(dev, "Failed to set rtc time.\n");
390 		return -1;
391 	}
392 
393 	writel(date, chip->base + SUNXI_RTC_YMD);
394 
395 	/*
396 	 * After writing the RTC YY-MM-DD register, the
397 	 * SUNXI_LOSC_CTRL_RTC_YMD_ACC bit is set and it will not
398 	 * be cleared until the real writing operation is finished
399 	 */
400 
401 	if (sunxi_rtc_wait(chip, SUNXI_LOSC_CTRL,
402 				SUNXI_LOSC_CTRL_RTC_YMD_ACC, 50)) {
403 		dev_err(dev, "Failed to set rtc time.\n");
404 		return -1;
405 	}
406 
407 	return 0;
408 }
409 
sunxi_rtc_alarm_irq_enable(struct device * dev,unsigned int enabled)410 static int sunxi_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
411 {
412 	struct sunxi_rtc_dev *chip = dev_get_drvdata(dev);
413 
414 	if (!enabled)
415 		sunxi_rtc_setaie(enabled, chip);
416 
417 	return 0;
418 }
419 
420 static const struct rtc_class_ops sunxi_rtc_ops = {
421 	.read_time		= sunxi_rtc_gettime,
422 	.set_time		= sunxi_rtc_settime,
423 	.read_alarm		= sunxi_rtc_getalarm,
424 	.set_alarm		= sunxi_rtc_setalarm,
425 	.alarm_irq_enable	= sunxi_rtc_alarm_irq_enable
426 };
427 
428 static const struct of_device_id sunxi_rtc_dt_ids[] = {
429 	{ .compatible = "allwinner,sun4i-a10-rtc", .data = &data_year_param[0] },
430 	{ .compatible = "allwinner,sun7i-a20-rtc", .data = &data_year_param[1] },
431 	{ /* sentinel */ },
432 };
433 MODULE_DEVICE_TABLE(of, sunxi_rtc_dt_ids);
434 
sunxi_rtc_probe(struct platform_device * pdev)435 static int sunxi_rtc_probe(struct platform_device *pdev)
436 {
437 	struct sunxi_rtc_dev *chip;
438 	struct resource *res;
439 	int ret;
440 
441 	chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
442 	if (!chip)
443 		return -ENOMEM;
444 
445 	platform_set_drvdata(pdev, chip);
446 	chip->dev = &pdev->dev;
447 
448 	chip->rtc = devm_rtc_allocate_device(&pdev->dev);
449 	if (IS_ERR(chip->rtc))
450 		return PTR_ERR(chip->rtc);
451 
452 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
453 	chip->base = devm_ioremap_resource(&pdev->dev, res);
454 	if (IS_ERR(chip->base))
455 		return PTR_ERR(chip->base);
456 
457 	chip->irq = platform_get_irq(pdev, 0);
458 	if (chip->irq < 0) {
459 		dev_err(&pdev->dev, "No IRQ resource\n");
460 		return chip->irq;
461 	}
462 	ret = devm_request_irq(&pdev->dev, chip->irq, sunxi_rtc_alarmirq,
463 			0, dev_name(&pdev->dev), chip);
464 	if (ret) {
465 		dev_err(&pdev->dev, "Could not request IRQ\n");
466 		return ret;
467 	}
468 
469 	chip->data_year = of_device_get_match_data(&pdev->dev);
470 	if (!chip->data_year) {
471 		dev_err(&pdev->dev, "Unable to setup RTC data\n");
472 		return -ENODEV;
473 	}
474 
475 	/* clear the alarm count value */
476 	writel(0, chip->base + SUNXI_ALRM_DHMS);
477 
478 	/* disable alarm, not generate irq pending */
479 	writel(0, chip->base + SUNXI_ALRM_EN);
480 
481 	/* disable alarm week/cnt irq, unset to cpu */
482 	writel(0, chip->base + SUNXI_ALRM_IRQ_EN);
483 
484 	/* clear alarm week/cnt irq pending */
485 	writel(SUNXI_ALRM_IRQ_STA_CNT_IRQ_PEND, chip->base +
486 			SUNXI_ALRM_IRQ_STA);
487 
488 	chip->rtc->ops = &sunxi_rtc_ops;
489 
490 	ret = rtc_register_device(chip->rtc);
491 	if (ret) {
492 		dev_err(&pdev->dev, "unable to register device\n");
493 		return ret;
494 	}
495 
496 	dev_info(&pdev->dev, "RTC enabled\n");
497 
498 	return 0;
499 }
500 
501 static struct platform_driver sunxi_rtc_driver = {
502 	.probe		= sunxi_rtc_probe,
503 	.driver		= {
504 		.name		= "sunxi-rtc",
505 		.of_match_table = sunxi_rtc_dt_ids,
506 	},
507 };
508 
509 module_platform_driver(sunxi_rtc_driver);
510 
511 MODULE_DESCRIPTION("sunxi RTC driver");
512 MODULE_AUTHOR("Carlo Caione <carlo.caione@gmail.com>");
513 MODULE_LICENSE("GPL");
514