xref: /openbmc/linux/drivers/rtc/rtc-sun6i.c (revision ae213c44)
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/clk.h>
24 #include <linux/clk-provider.h>
25 #include <linux/delay.h>
26 #include <linux/err.h>
27 #include <linux/fs.h>
28 #include <linux/init.h>
29 #include <linux/interrupt.h>
30 #include <linux/io.h>
31 #include <linux/kernel.h>
32 #include <linux/module.h>
33 #include <linux/of.h>
34 #include <linux/of_address.h>
35 #include <linux/of_device.h>
36 #include <linux/platform_device.h>
37 #include <linux/rtc.h>
38 #include <linux/slab.h>
39 #include <linux/types.h>
40 
41 /* Control register */
42 #define SUN6I_LOSC_CTRL				0x0000
43 #define SUN6I_LOSC_CTRL_KEY			(0x16aa << 16)
44 #define SUN6I_LOSC_CTRL_ALM_DHMS_ACC		BIT(9)
45 #define SUN6I_LOSC_CTRL_RTC_HMS_ACC		BIT(8)
46 #define SUN6I_LOSC_CTRL_RTC_YMD_ACC		BIT(7)
47 #define SUN6I_LOSC_CTRL_EXT_OSC			BIT(0)
48 #define SUN6I_LOSC_CTRL_ACC_MASK		GENMASK(9, 7)
49 
50 #define SUN6I_LOSC_CLK_PRESCAL			0x0008
51 
52 /* RTC */
53 #define SUN6I_RTC_YMD				0x0010
54 #define SUN6I_RTC_HMS				0x0014
55 
56 /* Alarm 0 (counter) */
57 #define SUN6I_ALRM_COUNTER			0x0020
58 #define SUN6I_ALRM_CUR_VAL			0x0024
59 #define SUN6I_ALRM_EN				0x0028
60 #define SUN6I_ALRM_EN_CNT_EN			BIT(0)
61 #define SUN6I_ALRM_IRQ_EN			0x002c
62 #define SUN6I_ALRM_IRQ_EN_CNT_IRQ_EN		BIT(0)
63 #define SUN6I_ALRM_IRQ_STA			0x0030
64 #define SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND		BIT(0)
65 
66 /* Alarm 1 (wall clock) */
67 #define SUN6I_ALRM1_EN				0x0044
68 #define SUN6I_ALRM1_IRQ_EN			0x0048
69 #define SUN6I_ALRM1_IRQ_STA			0x004c
70 #define SUN6I_ALRM1_IRQ_STA_WEEK_IRQ_PEND	BIT(0)
71 
72 /* Alarm config */
73 #define SUN6I_ALARM_CONFIG			0x0050
74 #define SUN6I_ALARM_CONFIG_WAKEUP		BIT(0)
75 
76 #define SUN6I_LOSC_OUT_GATING			0x0060
77 #define SUN6I_LOSC_OUT_GATING_EN_OFFSET		0
78 
79 /*
80  * Get date values
81  */
82 #define SUN6I_DATE_GET_DAY_VALUE(x)		((x)  & 0x0000001f)
83 #define SUN6I_DATE_GET_MON_VALUE(x)		(((x) & 0x00000f00) >> 8)
84 #define SUN6I_DATE_GET_YEAR_VALUE(x)		(((x) & 0x003f0000) >> 16)
85 #define SUN6I_LEAP_GET_VALUE(x)			(((x) & 0x00400000) >> 22)
86 
87 /*
88  * Get time values
89  */
90 #define SUN6I_TIME_GET_SEC_VALUE(x)		((x)  & 0x0000003f)
91 #define SUN6I_TIME_GET_MIN_VALUE(x)		(((x) & 0x00003f00) >> 8)
92 #define SUN6I_TIME_GET_HOUR_VALUE(x)		(((x) & 0x001f0000) >> 16)
93 
94 /*
95  * Set date values
96  */
97 #define SUN6I_DATE_SET_DAY_VALUE(x)		((x)       & 0x0000001f)
98 #define SUN6I_DATE_SET_MON_VALUE(x)		((x) <<  8 & 0x00000f00)
99 #define SUN6I_DATE_SET_YEAR_VALUE(x)		((x) << 16 & 0x003f0000)
100 #define SUN6I_LEAP_SET_VALUE(x)			((x) << 22 & 0x00400000)
101 
102 /*
103  * Set time values
104  */
105 #define SUN6I_TIME_SET_SEC_VALUE(x)		((x)       & 0x0000003f)
106 #define SUN6I_TIME_SET_MIN_VALUE(x)		((x) <<  8 & 0x00003f00)
107 #define SUN6I_TIME_SET_HOUR_VALUE(x)		((x) << 16 & 0x001f0000)
108 
109 /*
110  * The year parameter passed to the driver is usually an offset relative to
111  * the year 1900. This macro is used to convert this offset to another one
112  * relative to the minimum year allowed by the hardware.
113  *
114  * The year range is 1970 - 2033. This range is selected to match Allwinner's
115  * driver, even though it is somewhat limited.
116  */
117 #define SUN6I_YEAR_MIN				1970
118 #define SUN6I_YEAR_MAX				2033
119 #define SUN6I_YEAR_OFF				(SUN6I_YEAR_MIN - 1900)
120 
121 /*
122  * There are other differences between models, including:
123  *
124  *   - number of GPIO pins that can be configured to hold a certain level
125  *   - crypto-key related registers (H5, H6)
126  *   - boot process related (super standby, secondary processor entry address)
127  *     registers (R40, H6)
128  *   - SYS power domain controls (R40)
129  *   - DCXO controls (H6)
130  *   - RC oscillator calibration (H6)
131  *
132  * These functions are not covered by this driver.
133  */
134 struct sun6i_rtc_clk_data {
135 	unsigned long rc_osc_rate;
136 	unsigned int fixed_prescaler : 16;
137 	unsigned int has_prescaler : 1;
138 	unsigned int has_out_clk : 1;
139 	unsigned int export_iosc : 1;
140 };
141 
142 struct sun6i_rtc_dev {
143 	struct rtc_device *rtc;
144 	struct device *dev;
145 	const struct sun6i_rtc_clk_data *data;
146 	void __iomem *base;
147 	int irq;
148 	unsigned long alarm;
149 
150 	struct clk_hw hw;
151 	struct clk_hw *int_osc;
152 	struct clk *losc;
153 	struct clk *ext_losc;
154 
155 	spinlock_t lock;
156 };
157 
158 static struct sun6i_rtc_dev *sun6i_rtc;
159 
160 static unsigned long sun6i_rtc_osc_recalc_rate(struct clk_hw *hw,
161 					       unsigned long parent_rate)
162 {
163 	struct sun6i_rtc_dev *rtc = container_of(hw, struct sun6i_rtc_dev, hw);
164 	u32 val = 0;
165 
166 	val = readl(rtc->base + SUN6I_LOSC_CTRL);
167 	if (val & SUN6I_LOSC_CTRL_EXT_OSC)
168 		return parent_rate;
169 
170 	if (rtc->data->fixed_prescaler)
171 		parent_rate /= rtc->data->fixed_prescaler;
172 
173 	if (rtc->data->has_prescaler) {
174 		val = readl(rtc->base + SUN6I_LOSC_CLK_PRESCAL);
175 		val &= GENMASK(4, 0);
176 	}
177 
178 	return parent_rate / (val + 1);
179 }
180 
181 static u8 sun6i_rtc_osc_get_parent(struct clk_hw *hw)
182 {
183 	struct sun6i_rtc_dev *rtc = container_of(hw, struct sun6i_rtc_dev, hw);
184 
185 	return readl(rtc->base + SUN6I_LOSC_CTRL) & SUN6I_LOSC_CTRL_EXT_OSC;
186 }
187 
188 static int sun6i_rtc_osc_set_parent(struct clk_hw *hw, u8 index)
189 {
190 	struct sun6i_rtc_dev *rtc = container_of(hw, struct sun6i_rtc_dev, hw);
191 	unsigned long flags;
192 	u32 val;
193 
194 	if (index > 1)
195 		return -EINVAL;
196 
197 	spin_lock_irqsave(&rtc->lock, flags);
198 	val = readl(rtc->base + SUN6I_LOSC_CTRL);
199 	val &= ~SUN6I_LOSC_CTRL_EXT_OSC;
200 	val |= SUN6I_LOSC_CTRL_KEY;
201 	val |= index ? SUN6I_LOSC_CTRL_EXT_OSC : 0;
202 	writel(val, rtc->base + SUN6I_LOSC_CTRL);
203 	spin_unlock_irqrestore(&rtc->lock, flags);
204 
205 	return 0;
206 }
207 
208 static const struct clk_ops sun6i_rtc_osc_ops = {
209 	.recalc_rate	= sun6i_rtc_osc_recalc_rate,
210 
211 	.get_parent	= sun6i_rtc_osc_get_parent,
212 	.set_parent	= sun6i_rtc_osc_set_parent,
213 };
214 
215 static void __init sun6i_rtc_clk_init(struct device_node *node,
216 				      const struct sun6i_rtc_clk_data *data)
217 {
218 	struct clk_hw_onecell_data *clk_data;
219 	struct sun6i_rtc_dev *rtc;
220 	struct clk_init_data init = {
221 		.ops		= &sun6i_rtc_osc_ops,
222 		.name		= "losc",
223 	};
224 	const char *iosc_name = "rtc-int-osc";
225 	const char *clkout_name = "osc32k-out";
226 	const char *parents[2];
227 
228 	rtc = kzalloc(sizeof(*rtc), GFP_KERNEL);
229 	if (!rtc)
230 		return;
231 
232 	rtc->data = data;
233 	clk_data = kzalloc(struct_size(clk_data, hws, 3), GFP_KERNEL);
234 	if (!clk_data) {
235 		kfree(rtc);
236 		return;
237 	}
238 
239 	spin_lock_init(&rtc->lock);
240 
241 	rtc->base = of_io_request_and_map(node, 0, of_node_full_name(node));
242 	if (IS_ERR(rtc->base)) {
243 		pr_crit("Can't map RTC registers");
244 		goto err;
245 	}
246 
247 	/* Switch to the external, more precise, oscillator */
248 	writel(SUN6I_LOSC_CTRL_KEY | SUN6I_LOSC_CTRL_EXT_OSC,
249 	       rtc->base + SUN6I_LOSC_CTRL);
250 
251 	/* Yes, I know, this is ugly. */
252 	sun6i_rtc = rtc;
253 
254 	/* Deal with old DTs */
255 	if (!of_get_property(node, "clocks", NULL))
256 		goto err;
257 
258 	/* Only read IOSC name from device tree if it is exported */
259 	if (rtc->data->export_iosc)
260 		of_property_read_string_index(node, "clock-output-names", 2,
261 					      &iosc_name);
262 
263 	rtc->int_osc = clk_hw_register_fixed_rate_with_accuracy(NULL,
264 								iosc_name,
265 								NULL, 0,
266 								rtc->data->rc_osc_rate,
267 								300000000);
268 	if (IS_ERR(rtc->int_osc)) {
269 		pr_crit("Couldn't register the internal oscillator\n");
270 		return;
271 	}
272 
273 	parents[0] = clk_hw_get_name(rtc->int_osc);
274 	parents[1] = of_clk_get_parent_name(node, 0);
275 
276 	rtc->hw.init = &init;
277 
278 	init.parent_names = parents;
279 	init.num_parents = of_clk_get_parent_count(node) + 1;
280 	of_property_read_string_index(node, "clock-output-names", 0,
281 				      &init.name);
282 
283 	rtc->losc = clk_register(NULL, &rtc->hw);
284 	if (IS_ERR(rtc->losc)) {
285 		pr_crit("Couldn't register the LOSC clock\n");
286 		return;
287 	}
288 
289 	of_property_read_string_index(node, "clock-output-names", 1,
290 				      &clkout_name);
291 	rtc->ext_losc = clk_register_gate(NULL, clkout_name, rtc->hw.init->name,
292 					  0, rtc->base + SUN6I_LOSC_OUT_GATING,
293 					  SUN6I_LOSC_OUT_GATING_EN_OFFSET, 0,
294 					  &rtc->lock);
295 	if (IS_ERR(rtc->ext_losc)) {
296 		pr_crit("Couldn't register the LOSC external gate\n");
297 		return;
298 	}
299 
300 	clk_data->num = 2;
301 	clk_data->hws[0] = &rtc->hw;
302 	clk_data->hws[1] = __clk_get_hw(rtc->ext_losc);
303 	if (rtc->data->export_iosc) {
304 		clk_data->hws[2] = rtc->int_osc;
305 		clk_data->num = 3;
306 	}
307 	of_clk_add_hw_provider(node, of_clk_hw_onecell_get, clk_data);
308 	return;
309 
310 err:
311 	kfree(clk_data);
312 }
313 
314 static const struct sun6i_rtc_clk_data sun6i_a31_rtc_data = {
315 	.rc_osc_rate = 667000, /* datasheet says 600 ~ 700 KHz */
316 	.has_prescaler = 1,
317 };
318 
319 static void __init sun6i_a31_rtc_clk_init(struct device_node *node)
320 {
321 	sun6i_rtc_clk_init(node, &sun6i_a31_rtc_data);
322 }
323 CLK_OF_DECLARE_DRIVER(sun6i_a31_rtc_clk, "allwinner,sun6i-a31-rtc",
324 		      sun6i_a31_rtc_clk_init);
325 
326 static const struct sun6i_rtc_clk_data sun8i_a23_rtc_data = {
327 	.rc_osc_rate = 667000, /* datasheet says 600 ~ 700 KHz */
328 	.has_prescaler = 1,
329 	.has_out_clk = 1,
330 };
331 
332 static void __init sun8i_a23_rtc_clk_init(struct device_node *node)
333 {
334 	sun6i_rtc_clk_init(node, &sun8i_a23_rtc_data);
335 }
336 CLK_OF_DECLARE_DRIVER(sun8i_a23_rtc_clk, "allwinner,sun8i-a23-rtc",
337 		      sun8i_a23_rtc_clk_init);
338 
339 static const struct sun6i_rtc_clk_data sun8i_h3_rtc_data = {
340 	.rc_osc_rate = 16000000,
341 	.fixed_prescaler = 32,
342 	.has_prescaler = 1,
343 	.has_out_clk = 1,
344 	.export_iosc = 1,
345 };
346 
347 static void __init sun8i_h3_rtc_clk_init(struct device_node *node)
348 {
349 	sun6i_rtc_clk_init(node, &sun8i_h3_rtc_data);
350 }
351 CLK_OF_DECLARE_DRIVER(sun8i_h3_rtc_clk, "allwinner,sun8i-h3-rtc",
352 		      sun8i_h3_rtc_clk_init);
353 /* As far as we are concerned, clocks for H5 are the same as H3 */
354 CLK_OF_DECLARE_DRIVER(sun50i_h5_rtc_clk, "allwinner,sun50i-h5-rtc",
355 		      sun8i_h3_rtc_clk_init);
356 
357 static const struct sun6i_rtc_clk_data sun8i_v3_rtc_data = {
358 	.rc_osc_rate = 32000,
359 	.has_out_clk = 1,
360 };
361 
362 static void __init sun8i_v3_rtc_clk_init(struct device_node *node)
363 {
364 	sun6i_rtc_clk_init(node, &sun8i_v3_rtc_data);
365 }
366 CLK_OF_DECLARE_DRIVER(sun8i_v3_rtc_clk, "allwinner,sun8i-v3-rtc",
367 		      sun8i_v3_rtc_clk_init);
368 
369 static irqreturn_t sun6i_rtc_alarmirq(int irq, void *id)
370 {
371 	struct sun6i_rtc_dev *chip = (struct sun6i_rtc_dev *) id;
372 	irqreturn_t ret = IRQ_NONE;
373 	u32 val;
374 
375 	spin_lock(&chip->lock);
376 	val = readl(chip->base + SUN6I_ALRM_IRQ_STA);
377 
378 	if (val & SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND) {
379 		val |= SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND;
380 		writel(val, chip->base + SUN6I_ALRM_IRQ_STA);
381 
382 		rtc_update_irq(chip->rtc, 1, RTC_AF | RTC_IRQF);
383 
384 		ret = IRQ_HANDLED;
385 	}
386 	spin_unlock(&chip->lock);
387 
388 	return ret;
389 }
390 
391 static void sun6i_rtc_setaie(int to, struct sun6i_rtc_dev *chip)
392 {
393 	u32 alrm_val = 0;
394 	u32 alrm_irq_val = 0;
395 	u32 alrm_wake_val = 0;
396 	unsigned long flags;
397 
398 	if (to) {
399 		alrm_val = SUN6I_ALRM_EN_CNT_EN;
400 		alrm_irq_val = SUN6I_ALRM_IRQ_EN_CNT_IRQ_EN;
401 		alrm_wake_val = SUN6I_ALARM_CONFIG_WAKEUP;
402 	} else {
403 		writel(SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND,
404 		       chip->base + SUN6I_ALRM_IRQ_STA);
405 	}
406 
407 	spin_lock_irqsave(&chip->lock, flags);
408 	writel(alrm_val, chip->base + SUN6I_ALRM_EN);
409 	writel(alrm_irq_val, chip->base + SUN6I_ALRM_IRQ_EN);
410 	writel(alrm_wake_val, chip->base + SUN6I_ALARM_CONFIG);
411 	spin_unlock_irqrestore(&chip->lock, flags);
412 }
413 
414 static int sun6i_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
415 {
416 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
417 	u32 date, time;
418 
419 	/*
420 	 * read again in case it changes
421 	 */
422 	do {
423 		date = readl(chip->base + SUN6I_RTC_YMD);
424 		time = readl(chip->base + SUN6I_RTC_HMS);
425 	} while ((date != readl(chip->base + SUN6I_RTC_YMD)) ||
426 		 (time != readl(chip->base + SUN6I_RTC_HMS)));
427 
428 	rtc_tm->tm_sec  = SUN6I_TIME_GET_SEC_VALUE(time);
429 	rtc_tm->tm_min  = SUN6I_TIME_GET_MIN_VALUE(time);
430 	rtc_tm->tm_hour = SUN6I_TIME_GET_HOUR_VALUE(time);
431 
432 	rtc_tm->tm_mday = SUN6I_DATE_GET_DAY_VALUE(date);
433 	rtc_tm->tm_mon  = SUN6I_DATE_GET_MON_VALUE(date);
434 	rtc_tm->tm_year = SUN6I_DATE_GET_YEAR_VALUE(date);
435 
436 	rtc_tm->tm_mon  -= 1;
437 
438 	/*
439 	 * switch from (data_year->min)-relative offset to
440 	 * a (1900)-relative one
441 	 */
442 	rtc_tm->tm_year += SUN6I_YEAR_OFF;
443 
444 	return 0;
445 }
446 
447 static int sun6i_rtc_getalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
448 {
449 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
450 	unsigned long flags;
451 	u32 alrm_st;
452 	u32 alrm_en;
453 
454 	spin_lock_irqsave(&chip->lock, flags);
455 	alrm_en = readl(chip->base + SUN6I_ALRM_IRQ_EN);
456 	alrm_st = readl(chip->base + SUN6I_ALRM_IRQ_STA);
457 	spin_unlock_irqrestore(&chip->lock, flags);
458 
459 	wkalrm->enabled = !!(alrm_en & SUN6I_ALRM_EN_CNT_EN);
460 	wkalrm->pending = !!(alrm_st & SUN6I_ALRM_EN_CNT_EN);
461 	rtc_time_to_tm(chip->alarm, &wkalrm->time);
462 
463 	return 0;
464 }
465 
466 static int sun6i_rtc_setalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
467 {
468 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
469 	struct rtc_time *alrm_tm = &wkalrm->time;
470 	struct rtc_time tm_now;
471 	unsigned long time_now = 0;
472 	unsigned long time_set = 0;
473 	unsigned long time_gap = 0;
474 	int ret = 0;
475 
476 	ret = sun6i_rtc_gettime(dev, &tm_now);
477 	if (ret < 0) {
478 		dev_err(dev, "Error in getting time\n");
479 		return -EINVAL;
480 	}
481 
482 	rtc_tm_to_time(alrm_tm, &time_set);
483 	rtc_tm_to_time(&tm_now, &time_now);
484 	if (time_set <= time_now) {
485 		dev_err(dev, "Date to set in the past\n");
486 		return -EINVAL;
487 	}
488 
489 	time_gap = time_set - time_now;
490 
491 	if (time_gap > U32_MAX) {
492 		dev_err(dev, "Date too far in the future\n");
493 		return -EINVAL;
494 	}
495 
496 	sun6i_rtc_setaie(0, chip);
497 	writel(0, chip->base + SUN6I_ALRM_COUNTER);
498 	usleep_range(100, 300);
499 
500 	writel(time_gap, chip->base + SUN6I_ALRM_COUNTER);
501 	chip->alarm = time_set;
502 
503 	sun6i_rtc_setaie(wkalrm->enabled, chip);
504 
505 	return 0;
506 }
507 
508 static int sun6i_rtc_wait(struct sun6i_rtc_dev *chip, int offset,
509 			  unsigned int mask, unsigned int ms_timeout)
510 {
511 	const unsigned long timeout = jiffies + msecs_to_jiffies(ms_timeout);
512 	u32 reg;
513 
514 	do {
515 		reg = readl(chip->base + offset);
516 		reg &= mask;
517 
518 		if (!reg)
519 			return 0;
520 
521 	} while (time_before(jiffies, timeout));
522 
523 	return -ETIMEDOUT;
524 }
525 
526 static int sun6i_rtc_settime(struct device *dev, struct rtc_time *rtc_tm)
527 {
528 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
529 	u32 date = 0;
530 	u32 time = 0;
531 	int year;
532 
533 	year = rtc_tm->tm_year + 1900;
534 	if (year < SUN6I_YEAR_MIN || year > SUN6I_YEAR_MAX) {
535 		dev_err(dev, "rtc only supports year in range %d - %d\n",
536 			SUN6I_YEAR_MIN, SUN6I_YEAR_MAX);
537 		return -EINVAL;
538 	}
539 
540 	rtc_tm->tm_year -= SUN6I_YEAR_OFF;
541 	rtc_tm->tm_mon += 1;
542 
543 	date = SUN6I_DATE_SET_DAY_VALUE(rtc_tm->tm_mday) |
544 		SUN6I_DATE_SET_MON_VALUE(rtc_tm->tm_mon)  |
545 		SUN6I_DATE_SET_YEAR_VALUE(rtc_tm->tm_year);
546 
547 	if (is_leap_year(year))
548 		date |= SUN6I_LEAP_SET_VALUE(1);
549 
550 	time = SUN6I_TIME_SET_SEC_VALUE(rtc_tm->tm_sec)  |
551 		SUN6I_TIME_SET_MIN_VALUE(rtc_tm->tm_min)  |
552 		SUN6I_TIME_SET_HOUR_VALUE(rtc_tm->tm_hour);
553 
554 	/* Check whether registers are writable */
555 	if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
556 			   SUN6I_LOSC_CTRL_ACC_MASK, 50)) {
557 		dev_err(dev, "rtc is still busy.\n");
558 		return -EBUSY;
559 	}
560 
561 	writel(time, chip->base + SUN6I_RTC_HMS);
562 
563 	/*
564 	 * After writing the RTC HH-MM-SS register, the
565 	 * SUN6I_LOSC_CTRL_RTC_HMS_ACC bit is set and it will not
566 	 * be cleared until the real writing operation is finished
567 	 */
568 
569 	if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
570 			   SUN6I_LOSC_CTRL_RTC_HMS_ACC, 50)) {
571 		dev_err(dev, "Failed to set rtc time.\n");
572 		return -ETIMEDOUT;
573 	}
574 
575 	writel(date, chip->base + SUN6I_RTC_YMD);
576 
577 	/*
578 	 * After writing the RTC YY-MM-DD register, the
579 	 * SUN6I_LOSC_CTRL_RTC_YMD_ACC bit is set and it will not
580 	 * be cleared until the real writing operation is finished
581 	 */
582 
583 	if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
584 			   SUN6I_LOSC_CTRL_RTC_YMD_ACC, 50)) {
585 		dev_err(dev, "Failed to set rtc time.\n");
586 		return -ETIMEDOUT;
587 	}
588 
589 	return 0;
590 }
591 
592 static int sun6i_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
593 {
594 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
595 
596 	if (!enabled)
597 		sun6i_rtc_setaie(enabled, chip);
598 
599 	return 0;
600 }
601 
602 static const struct rtc_class_ops sun6i_rtc_ops = {
603 	.read_time		= sun6i_rtc_gettime,
604 	.set_time		= sun6i_rtc_settime,
605 	.read_alarm		= sun6i_rtc_getalarm,
606 	.set_alarm		= sun6i_rtc_setalarm,
607 	.alarm_irq_enable	= sun6i_rtc_alarm_irq_enable
608 };
609 
610 static int sun6i_rtc_probe(struct platform_device *pdev)
611 {
612 	struct sun6i_rtc_dev *chip = sun6i_rtc;
613 	int ret;
614 
615 	if (!chip)
616 		return -ENODEV;
617 
618 	platform_set_drvdata(pdev, chip);
619 	chip->dev = &pdev->dev;
620 
621 	chip->irq = platform_get_irq(pdev, 0);
622 	if (chip->irq < 0) {
623 		dev_err(&pdev->dev, "No IRQ resource\n");
624 		return chip->irq;
625 	}
626 
627 	ret = devm_request_irq(&pdev->dev, chip->irq, sun6i_rtc_alarmirq,
628 			       0, dev_name(&pdev->dev), chip);
629 	if (ret) {
630 		dev_err(&pdev->dev, "Could not request IRQ\n");
631 		return ret;
632 	}
633 
634 	/* clear the alarm counter value */
635 	writel(0, chip->base + SUN6I_ALRM_COUNTER);
636 
637 	/* disable counter alarm */
638 	writel(0, chip->base + SUN6I_ALRM_EN);
639 
640 	/* disable counter alarm interrupt */
641 	writel(0, chip->base + SUN6I_ALRM_IRQ_EN);
642 
643 	/* disable week alarm */
644 	writel(0, chip->base + SUN6I_ALRM1_EN);
645 
646 	/* disable week alarm interrupt */
647 	writel(0, chip->base + SUN6I_ALRM1_IRQ_EN);
648 
649 	/* clear counter alarm pending interrupts */
650 	writel(SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND,
651 	       chip->base + SUN6I_ALRM_IRQ_STA);
652 
653 	/* clear week alarm pending interrupts */
654 	writel(SUN6I_ALRM1_IRQ_STA_WEEK_IRQ_PEND,
655 	       chip->base + SUN6I_ALRM1_IRQ_STA);
656 
657 	/* disable alarm wakeup */
658 	writel(0, chip->base + SUN6I_ALARM_CONFIG);
659 
660 	clk_prepare_enable(chip->losc);
661 
662 	chip->rtc = devm_rtc_device_register(&pdev->dev, "rtc-sun6i",
663 					     &sun6i_rtc_ops, THIS_MODULE);
664 	if (IS_ERR(chip->rtc)) {
665 		dev_err(&pdev->dev, "unable to register device\n");
666 		return PTR_ERR(chip->rtc);
667 	}
668 
669 	dev_info(&pdev->dev, "RTC enabled\n");
670 
671 	return 0;
672 }
673 
674 /*
675  * As far as RTC functionality goes, all models are the same. The
676  * datasheets claim that different models have different number of
677  * registers available for non-volatile storage, but experiments show
678  * that all SoCs have 16 registers available for this purpose.
679  */
680 static const struct of_device_id sun6i_rtc_dt_ids[] = {
681 	{ .compatible = "allwinner,sun6i-a31-rtc" },
682 	{ .compatible = "allwinner,sun8i-a23-rtc" },
683 	{ .compatible = "allwinner,sun8i-h3-rtc" },
684 	{ .compatible = "allwinner,sun8i-v3-rtc" },
685 	{ .compatible = "allwinner,sun50i-h5-rtc" },
686 	{ /* sentinel */ },
687 };
688 MODULE_DEVICE_TABLE(of, sun6i_rtc_dt_ids);
689 
690 static struct platform_driver sun6i_rtc_driver = {
691 	.probe		= sun6i_rtc_probe,
692 	.driver		= {
693 		.name		= "sun6i-rtc",
694 		.of_match_table = sun6i_rtc_dt_ids,
695 	},
696 };
697 builtin_platform_driver(sun6i_rtc_driver);
698