xref: /openbmc/linux/drivers/rtc/rtc-sun6i.c (revision b830f94f)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * An RTC driver for Allwinner A31/A23
4  *
5  * Copyright (c) 2014, Chen-Yu Tsai <wens@csie.org>
6  *
7  * based on rtc-sunxi.c
8  *
9  * An RTC driver for Allwinner A10/A20
10  *
11  * Copyright (c) 2013, Carlo Caione <carlo.caione@gmail.com>
12  */
13 
14 #include <linux/clk.h>
15 #include <linux/clk-provider.h>
16 #include <linux/delay.h>
17 #include <linux/err.h>
18 #include <linux/fs.h>
19 #include <linux/init.h>
20 #include <linux/interrupt.h>
21 #include <linux/io.h>
22 #include <linux/kernel.h>
23 #include <linux/module.h>
24 #include <linux/of.h>
25 #include <linux/of_address.h>
26 #include <linux/of_device.h>
27 #include <linux/platform_device.h>
28 #include <linux/rtc.h>
29 #include <linux/slab.h>
30 #include <linux/types.h>
31 
32 /* Control register */
33 #define SUN6I_LOSC_CTRL				0x0000
34 #define SUN6I_LOSC_CTRL_KEY			(0x16aa << 16)
35 #define SUN6I_LOSC_CTRL_ALM_DHMS_ACC		BIT(9)
36 #define SUN6I_LOSC_CTRL_RTC_HMS_ACC		BIT(8)
37 #define SUN6I_LOSC_CTRL_RTC_YMD_ACC		BIT(7)
38 #define SUN6I_LOSC_CTRL_EXT_OSC			BIT(0)
39 #define SUN6I_LOSC_CTRL_ACC_MASK		GENMASK(9, 7)
40 
41 #define SUN6I_LOSC_CLK_PRESCAL			0x0008
42 
43 /* RTC */
44 #define SUN6I_RTC_YMD				0x0010
45 #define SUN6I_RTC_HMS				0x0014
46 
47 /* Alarm 0 (counter) */
48 #define SUN6I_ALRM_COUNTER			0x0020
49 #define SUN6I_ALRM_CUR_VAL			0x0024
50 #define SUN6I_ALRM_EN				0x0028
51 #define SUN6I_ALRM_EN_CNT_EN			BIT(0)
52 #define SUN6I_ALRM_IRQ_EN			0x002c
53 #define SUN6I_ALRM_IRQ_EN_CNT_IRQ_EN		BIT(0)
54 #define SUN6I_ALRM_IRQ_STA			0x0030
55 #define SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND		BIT(0)
56 
57 /* Alarm 1 (wall clock) */
58 #define SUN6I_ALRM1_EN				0x0044
59 #define SUN6I_ALRM1_IRQ_EN			0x0048
60 #define SUN6I_ALRM1_IRQ_STA			0x004c
61 #define SUN6I_ALRM1_IRQ_STA_WEEK_IRQ_PEND	BIT(0)
62 
63 /* Alarm config */
64 #define SUN6I_ALARM_CONFIG			0x0050
65 #define SUN6I_ALARM_CONFIG_WAKEUP		BIT(0)
66 
67 #define SUN6I_LOSC_OUT_GATING			0x0060
68 #define SUN6I_LOSC_OUT_GATING_EN_OFFSET		0
69 
70 /*
71  * Get date values
72  */
73 #define SUN6I_DATE_GET_DAY_VALUE(x)		((x)  & 0x0000001f)
74 #define SUN6I_DATE_GET_MON_VALUE(x)		(((x) & 0x00000f00) >> 8)
75 #define SUN6I_DATE_GET_YEAR_VALUE(x)		(((x) & 0x003f0000) >> 16)
76 #define SUN6I_LEAP_GET_VALUE(x)			(((x) & 0x00400000) >> 22)
77 
78 /*
79  * Get time values
80  */
81 #define SUN6I_TIME_GET_SEC_VALUE(x)		((x)  & 0x0000003f)
82 #define SUN6I_TIME_GET_MIN_VALUE(x)		(((x) & 0x00003f00) >> 8)
83 #define SUN6I_TIME_GET_HOUR_VALUE(x)		(((x) & 0x001f0000) >> 16)
84 
85 /*
86  * Set date values
87  */
88 #define SUN6I_DATE_SET_DAY_VALUE(x)		((x)       & 0x0000001f)
89 #define SUN6I_DATE_SET_MON_VALUE(x)		((x) <<  8 & 0x00000f00)
90 #define SUN6I_DATE_SET_YEAR_VALUE(x)		((x) << 16 & 0x003f0000)
91 #define SUN6I_LEAP_SET_VALUE(x)			((x) << 22 & 0x00400000)
92 
93 /*
94  * Set time values
95  */
96 #define SUN6I_TIME_SET_SEC_VALUE(x)		((x)       & 0x0000003f)
97 #define SUN6I_TIME_SET_MIN_VALUE(x)		((x) <<  8 & 0x00003f00)
98 #define SUN6I_TIME_SET_HOUR_VALUE(x)		((x) << 16 & 0x001f0000)
99 
100 /*
101  * The year parameter passed to the driver is usually an offset relative to
102  * the year 1900. This macro is used to convert this offset to another one
103  * relative to the minimum year allowed by the hardware.
104  *
105  * The year range is 1970 - 2033. This range is selected to match Allwinner's
106  * driver, even though it is somewhat limited.
107  */
108 #define SUN6I_YEAR_MIN				1970
109 #define SUN6I_YEAR_MAX				2033
110 #define SUN6I_YEAR_OFF				(SUN6I_YEAR_MIN - 1900)
111 
112 /*
113  * There are other differences between models, including:
114  *
115  *   - number of GPIO pins that can be configured to hold a certain level
116  *   - crypto-key related registers (H5, H6)
117  *   - boot process related (super standby, secondary processor entry address)
118  *     registers (R40, H6)
119  *   - SYS power domain controls (R40)
120  *   - DCXO controls (H6)
121  *   - RC oscillator calibration (H6)
122  *
123  * These functions are not covered by this driver.
124  */
125 struct sun6i_rtc_clk_data {
126 	unsigned long rc_osc_rate;
127 	unsigned int fixed_prescaler : 16;
128 	unsigned int has_prescaler : 1;
129 	unsigned int has_out_clk : 1;
130 	unsigned int export_iosc : 1;
131 };
132 
133 struct sun6i_rtc_dev {
134 	struct rtc_device *rtc;
135 	struct device *dev;
136 	const struct sun6i_rtc_clk_data *data;
137 	void __iomem *base;
138 	int irq;
139 	unsigned long alarm;
140 
141 	struct clk_hw hw;
142 	struct clk_hw *int_osc;
143 	struct clk *losc;
144 	struct clk *ext_losc;
145 
146 	spinlock_t lock;
147 };
148 
149 static struct sun6i_rtc_dev *sun6i_rtc;
150 
151 static unsigned long sun6i_rtc_osc_recalc_rate(struct clk_hw *hw,
152 					       unsigned long parent_rate)
153 {
154 	struct sun6i_rtc_dev *rtc = container_of(hw, struct sun6i_rtc_dev, hw);
155 	u32 val = 0;
156 
157 	val = readl(rtc->base + SUN6I_LOSC_CTRL);
158 	if (val & SUN6I_LOSC_CTRL_EXT_OSC)
159 		return parent_rate;
160 
161 	if (rtc->data->fixed_prescaler)
162 		parent_rate /= rtc->data->fixed_prescaler;
163 
164 	if (rtc->data->has_prescaler) {
165 		val = readl(rtc->base + SUN6I_LOSC_CLK_PRESCAL);
166 		val &= GENMASK(4, 0);
167 	}
168 
169 	return parent_rate / (val + 1);
170 }
171 
172 static u8 sun6i_rtc_osc_get_parent(struct clk_hw *hw)
173 {
174 	struct sun6i_rtc_dev *rtc = container_of(hw, struct sun6i_rtc_dev, hw);
175 
176 	return readl(rtc->base + SUN6I_LOSC_CTRL) & SUN6I_LOSC_CTRL_EXT_OSC;
177 }
178 
179 static int sun6i_rtc_osc_set_parent(struct clk_hw *hw, u8 index)
180 {
181 	struct sun6i_rtc_dev *rtc = container_of(hw, struct sun6i_rtc_dev, hw);
182 	unsigned long flags;
183 	u32 val;
184 
185 	if (index > 1)
186 		return -EINVAL;
187 
188 	spin_lock_irqsave(&rtc->lock, flags);
189 	val = readl(rtc->base + SUN6I_LOSC_CTRL);
190 	val &= ~SUN6I_LOSC_CTRL_EXT_OSC;
191 	val |= SUN6I_LOSC_CTRL_KEY;
192 	val |= index ? SUN6I_LOSC_CTRL_EXT_OSC : 0;
193 	writel(val, rtc->base + SUN6I_LOSC_CTRL);
194 	spin_unlock_irqrestore(&rtc->lock, flags);
195 
196 	return 0;
197 }
198 
199 static const struct clk_ops sun6i_rtc_osc_ops = {
200 	.recalc_rate	= sun6i_rtc_osc_recalc_rate,
201 
202 	.get_parent	= sun6i_rtc_osc_get_parent,
203 	.set_parent	= sun6i_rtc_osc_set_parent,
204 };
205 
206 static void __init sun6i_rtc_clk_init(struct device_node *node,
207 				      const struct sun6i_rtc_clk_data *data)
208 {
209 	struct clk_hw_onecell_data *clk_data;
210 	struct sun6i_rtc_dev *rtc;
211 	struct clk_init_data init = {
212 		.ops		= &sun6i_rtc_osc_ops,
213 		.name		= "losc",
214 	};
215 	const char *iosc_name = "rtc-int-osc";
216 	const char *clkout_name = "osc32k-out";
217 	const char *parents[2];
218 
219 	rtc = kzalloc(sizeof(*rtc), GFP_KERNEL);
220 	if (!rtc)
221 		return;
222 
223 	rtc->data = data;
224 	clk_data = kzalloc(struct_size(clk_data, hws, 3), GFP_KERNEL);
225 	if (!clk_data) {
226 		kfree(rtc);
227 		return;
228 	}
229 
230 	spin_lock_init(&rtc->lock);
231 
232 	rtc->base = of_io_request_and_map(node, 0, of_node_full_name(node));
233 	if (IS_ERR(rtc->base)) {
234 		pr_crit("Can't map RTC registers");
235 		goto err;
236 	}
237 
238 	/* Switch to the external, more precise, oscillator */
239 	writel(SUN6I_LOSC_CTRL_KEY | SUN6I_LOSC_CTRL_EXT_OSC,
240 	       rtc->base + SUN6I_LOSC_CTRL);
241 
242 	/* Yes, I know, this is ugly. */
243 	sun6i_rtc = rtc;
244 
245 	/* Deal with old DTs */
246 	if (!of_get_property(node, "clocks", NULL))
247 		goto err;
248 
249 	/* Only read IOSC name from device tree if it is exported */
250 	if (rtc->data->export_iosc)
251 		of_property_read_string_index(node, "clock-output-names", 2,
252 					      &iosc_name);
253 
254 	rtc->int_osc = clk_hw_register_fixed_rate_with_accuracy(NULL,
255 								iosc_name,
256 								NULL, 0,
257 								rtc->data->rc_osc_rate,
258 								300000000);
259 	if (IS_ERR(rtc->int_osc)) {
260 		pr_crit("Couldn't register the internal oscillator\n");
261 		return;
262 	}
263 
264 	parents[0] = clk_hw_get_name(rtc->int_osc);
265 	parents[1] = of_clk_get_parent_name(node, 0);
266 
267 	rtc->hw.init = &init;
268 
269 	init.parent_names = parents;
270 	init.num_parents = of_clk_get_parent_count(node) + 1;
271 	of_property_read_string_index(node, "clock-output-names", 0,
272 				      &init.name);
273 
274 	rtc->losc = clk_register(NULL, &rtc->hw);
275 	if (IS_ERR(rtc->losc)) {
276 		pr_crit("Couldn't register the LOSC clock\n");
277 		return;
278 	}
279 
280 	of_property_read_string_index(node, "clock-output-names", 1,
281 				      &clkout_name);
282 	rtc->ext_losc = clk_register_gate(NULL, clkout_name, rtc->hw.init->name,
283 					  0, rtc->base + SUN6I_LOSC_OUT_GATING,
284 					  SUN6I_LOSC_OUT_GATING_EN_OFFSET, 0,
285 					  &rtc->lock);
286 	if (IS_ERR(rtc->ext_losc)) {
287 		pr_crit("Couldn't register the LOSC external gate\n");
288 		return;
289 	}
290 
291 	clk_data->num = 2;
292 	clk_data->hws[0] = &rtc->hw;
293 	clk_data->hws[1] = __clk_get_hw(rtc->ext_losc);
294 	if (rtc->data->export_iosc) {
295 		clk_data->hws[2] = rtc->int_osc;
296 		clk_data->num = 3;
297 	}
298 	of_clk_add_hw_provider(node, of_clk_hw_onecell_get, clk_data);
299 	return;
300 
301 err:
302 	kfree(clk_data);
303 }
304 
305 static const struct sun6i_rtc_clk_data sun6i_a31_rtc_data = {
306 	.rc_osc_rate = 667000, /* datasheet says 600 ~ 700 KHz */
307 	.has_prescaler = 1,
308 };
309 
310 static void __init sun6i_a31_rtc_clk_init(struct device_node *node)
311 {
312 	sun6i_rtc_clk_init(node, &sun6i_a31_rtc_data);
313 }
314 CLK_OF_DECLARE_DRIVER(sun6i_a31_rtc_clk, "allwinner,sun6i-a31-rtc",
315 		      sun6i_a31_rtc_clk_init);
316 
317 static const struct sun6i_rtc_clk_data sun8i_a23_rtc_data = {
318 	.rc_osc_rate = 667000, /* datasheet says 600 ~ 700 KHz */
319 	.has_prescaler = 1,
320 	.has_out_clk = 1,
321 };
322 
323 static void __init sun8i_a23_rtc_clk_init(struct device_node *node)
324 {
325 	sun6i_rtc_clk_init(node, &sun8i_a23_rtc_data);
326 }
327 CLK_OF_DECLARE_DRIVER(sun8i_a23_rtc_clk, "allwinner,sun8i-a23-rtc",
328 		      sun8i_a23_rtc_clk_init);
329 
330 static const struct sun6i_rtc_clk_data sun8i_h3_rtc_data = {
331 	.rc_osc_rate = 16000000,
332 	.fixed_prescaler = 32,
333 	.has_prescaler = 1,
334 	.has_out_clk = 1,
335 	.export_iosc = 1,
336 };
337 
338 static void __init sun8i_h3_rtc_clk_init(struct device_node *node)
339 {
340 	sun6i_rtc_clk_init(node, &sun8i_h3_rtc_data);
341 }
342 CLK_OF_DECLARE_DRIVER(sun8i_h3_rtc_clk, "allwinner,sun8i-h3-rtc",
343 		      sun8i_h3_rtc_clk_init);
344 /* As far as we are concerned, clocks for H5 are the same as H3 */
345 CLK_OF_DECLARE_DRIVER(sun50i_h5_rtc_clk, "allwinner,sun50i-h5-rtc",
346 		      sun8i_h3_rtc_clk_init);
347 
348 static const struct sun6i_rtc_clk_data sun8i_v3_rtc_data = {
349 	.rc_osc_rate = 32000,
350 	.has_out_clk = 1,
351 };
352 
353 static void __init sun8i_v3_rtc_clk_init(struct device_node *node)
354 {
355 	sun6i_rtc_clk_init(node, &sun8i_v3_rtc_data);
356 }
357 CLK_OF_DECLARE_DRIVER(sun8i_v3_rtc_clk, "allwinner,sun8i-v3-rtc",
358 		      sun8i_v3_rtc_clk_init);
359 
360 static irqreturn_t sun6i_rtc_alarmirq(int irq, void *id)
361 {
362 	struct sun6i_rtc_dev *chip = (struct sun6i_rtc_dev *) id;
363 	irqreturn_t ret = IRQ_NONE;
364 	u32 val;
365 
366 	spin_lock(&chip->lock);
367 	val = readl(chip->base + SUN6I_ALRM_IRQ_STA);
368 
369 	if (val & SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND) {
370 		val |= SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND;
371 		writel(val, chip->base + SUN6I_ALRM_IRQ_STA);
372 
373 		rtc_update_irq(chip->rtc, 1, RTC_AF | RTC_IRQF);
374 
375 		ret = IRQ_HANDLED;
376 	}
377 	spin_unlock(&chip->lock);
378 
379 	return ret;
380 }
381 
382 static void sun6i_rtc_setaie(int to, struct sun6i_rtc_dev *chip)
383 {
384 	u32 alrm_val = 0;
385 	u32 alrm_irq_val = 0;
386 	u32 alrm_wake_val = 0;
387 	unsigned long flags;
388 
389 	if (to) {
390 		alrm_val = SUN6I_ALRM_EN_CNT_EN;
391 		alrm_irq_val = SUN6I_ALRM_IRQ_EN_CNT_IRQ_EN;
392 		alrm_wake_val = SUN6I_ALARM_CONFIG_WAKEUP;
393 	} else {
394 		writel(SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND,
395 		       chip->base + SUN6I_ALRM_IRQ_STA);
396 	}
397 
398 	spin_lock_irqsave(&chip->lock, flags);
399 	writel(alrm_val, chip->base + SUN6I_ALRM_EN);
400 	writel(alrm_irq_val, chip->base + SUN6I_ALRM_IRQ_EN);
401 	writel(alrm_wake_val, chip->base + SUN6I_ALARM_CONFIG);
402 	spin_unlock_irqrestore(&chip->lock, flags);
403 }
404 
405 static int sun6i_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
406 {
407 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
408 	u32 date, time;
409 
410 	/*
411 	 * read again in case it changes
412 	 */
413 	do {
414 		date = readl(chip->base + SUN6I_RTC_YMD);
415 		time = readl(chip->base + SUN6I_RTC_HMS);
416 	} while ((date != readl(chip->base + SUN6I_RTC_YMD)) ||
417 		 (time != readl(chip->base + SUN6I_RTC_HMS)));
418 
419 	rtc_tm->tm_sec  = SUN6I_TIME_GET_SEC_VALUE(time);
420 	rtc_tm->tm_min  = SUN6I_TIME_GET_MIN_VALUE(time);
421 	rtc_tm->tm_hour = SUN6I_TIME_GET_HOUR_VALUE(time);
422 
423 	rtc_tm->tm_mday = SUN6I_DATE_GET_DAY_VALUE(date);
424 	rtc_tm->tm_mon  = SUN6I_DATE_GET_MON_VALUE(date);
425 	rtc_tm->tm_year = SUN6I_DATE_GET_YEAR_VALUE(date);
426 
427 	rtc_tm->tm_mon  -= 1;
428 
429 	/*
430 	 * switch from (data_year->min)-relative offset to
431 	 * a (1900)-relative one
432 	 */
433 	rtc_tm->tm_year += SUN6I_YEAR_OFF;
434 
435 	return 0;
436 }
437 
438 static int sun6i_rtc_getalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
439 {
440 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
441 	unsigned long flags;
442 	u32 alrm_st;
443 	u32 alrm_en;
444 
445 	spin_lock_irqsave(&chip->lock, flags);
446 	alrm_en = readl(chip->base + SUN6I_ALRM_IRQ_EN);
447 	alrm_st = readl(chip->base + SUN6I_ALRM_IRQ_STA);
448 	spin_unlock_irqrestore(&chip->lock, flags);
449 
450 	wkalrm->enabled = !!(alrm_en & SUN6I_ALRM_EN_CNT_EN);
451 	wkalrm->pending = !!(alrm_st & SUN6I_ALRM_EN_CNT_EN);
452 	rtc_time_to_tm(chip->alarm, &wkalrm->time);
453 
454 	return 0;
455 }
456 
457 static int sun6i_rtc_setalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
458 {
459 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
460 	struct rtc_time *alrm_tm = &wkalrm->time;
461 	struct rtc_time tm_now;
462 	unsigned long time_now = 0;
463 	unsigned long time_set = 0;
464 	unsigned long time_gap = 0;
465 	int ret = 0;
466 
467 	ret = sun6i_rtc_gettime(dev, &tm_now);
468 	if (ret < 0) {
469 		dev_err(dev, "Error in getting time\n");
470 		return -EINVAL;
471 	}
472 
473 	rtc_tm_to_time(alrm_tm, &time_set);
474 	rtc_tm_to_time(&tm_now, &time_now);
475 	if (time_set <= time_now) {
476 		dev_err(dev, "Date to set in the past\n");
477 		return -EINVAL;
478 	}
479 
480 	time_gap = time_set - time_now;
481 
482 	if (time_gap > U32_MAX) {
483 		dev_err(dev, "Date too far in the future\n");
484 		return -EINVAL;
485 	}
486 
487 	sun6i_rtc_setaie(0, chip);
488 	writel(0, chip->base + SUN6I_ALRM_COUNTER);
489 	usleep_range(100, 300);
490 
491 	writel(time_gap, chip->base + SUN6I_ALRM_COUNTER);
492 	chip->alarm = time_set;
493 
494 	sun6i_rtc_setaie(wkalrm->enabled, chip);
495 
496 	return 0;
497 }
498 
499 static int sun6i_rtc_wait(struct sun6i_rtc_dev *chip, int offset,
500 			  unsigned int mask, unsigned int ms_timeout)
501 {
502 	const unsigned long timeout = jiffies + msecs_to_jiffies(ms_timeout);
503 	u32 reg;
504 
505 	do {
506 		reg = readl(chip->base + offset);
507 		reg &= mask;
508 
509 		if (!reg)
510 			return 0;
511 
512 	} while (time_before(jiffies, timeout));
513 
514 	return -ETIMEDOUT;
515 }
516 
517 static int sun6i_rtc_settime(struct device *dev, struct rtc_time *rtc_tm)
518 {
519 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
520 	u32 date = 0;
521 	u32 time = 0;
522 	int year;
523 
524 	year = rtc_tm->tm_year + 1900;
525 	if (year < SUN6I_YEAR_MIN || year > SUN6I_YEAR_MAX) {
526 		dev_err(dev, "rtc only supports year in range %d - %d\n",
527 			SUN6I_YEAR_MIN, SUN6I_YEAR_MAX);
528 		return -EINVAL;
529 	}
530 
531 	rtc_tm->tm_year -= SUN6I_YEAR_OFF;
532 	rtc_tm->tm_mon += 1;
533 
534 	date = SUN6I_DATE_SET_DAY_VALUE(rtc_tm->tm_mday) |
535 		SUN6I_DATE_SET_MON_VALUE(rtc_tm->tm_mon)  |
536 		SUN6I_DATE_SET_YEAR_VALUE(rtc_tm->tm_year);
537 
538 	if (is_leap_year(year))
539 		date |= SUN6I_LEAP_SET_VALUE(1);
540 
541 	time = SUN6I_TIME_SET_SEC_VALUE(rtc_tm->tm_sec)  |
542 		SUN6I_TIME_SET_MIN_VALUE(rtc_tm->tm_min)  |
543 		SUN6I_TIME_SET_HOUR_VALUE(rtc_tm->tm_hour);
544 
545 	/* Check whether registers are writable */
546 	if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
547 			   SUN6I_LOSC_CTRL_ACC_MASK, 50)) {
548 		dev_err(dev, "rtc is still busy.\n");
549 		return -EBUSY;
550 	}
551 
552 	writel(time, chip->base + SUN6I_RTC_HMS);
553 
554 	/*
555 	 * After writing the RTC HH-MM-SS register, the
556 	 * SUN6I_LOSC_CTRL_RTC_HMS_ACC bit is set and it will not
557 	 * be cleared until the real writing operation is finished
558 	 */
559 
560 	if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
561 			   SUN6I_LOSC_CTRL_RTC_HMS_ACC, 50)) {
562 		dev_err(dev, "Failed to set rtc time.\n");
563 		return -ETIMEDOUT;
564 	}
565 
566 	writel(date, chip->base + SUN6I_RTC_YMD);
567 
568 	/*
569 	 * After writing the RTC YY-MM-DD register, the
570 	 * SUN6I_LOSC_CTRL_RTC_YMD_ACC bit is set and it will not
571 	 * be cleared until the real writing operation is finished
572 	 */
573 
574 	if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
575 			   SUN6I_LOSC_CTRL_RTC_YMD_ACC, 50)) {
576 		dev_err(dev, "Failed to set rtc time.\n");
577 		return -ETIMEDOUT;
578 	}
579 
580 	return 0;
581 }
582 
583 static int sun6i_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
584 {
585 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
586 
587 	if (!enabled)
588 		sun6i_rtc_setaie(enabled, chip);
589 
590 	return 0;
591 }
592 
593 static const struct rtc_class_ops sun6i_rtc_ops = {
594 	.read_time		= sun6i_rtc_gettime,
595 	.set_time		= sun6i_rtc_settime,
596 	.read_alarm		= sun6i_rtc_getalarm,
597 	.set_alarm		= sun6i_rtc_setalarm,
598 	.alarm_irq_enable	= sun6i_rtc_alarm_irq_enable
599 };
600 
601 static int sun6i_rtc_probe(struct platform_device *pdev)
602 {
603 	struct sun6i_rtc_dev *chip = sun6i_rtc;
604 	int ret;
605 
606 	if (!chip)
607 		return -ENODEV;
608 
609 	platform_set_drvdata(pdev, chip);
610 	chip->dev = &pdev->dev;
611 
612 	chip->irq = platform_get_irq(pdev, 0);
613 	if (chip->irq < 0) {
614 		dev_err(&pdev->dev, "No IRQ resource\n");
615 		return chip->irq;
616 	}
617 
618 	ret = devm_request_irq(&pdev->dev, chip->irq, sun6i_rtc_alarmirq,
619 			       0, dev_name(&pdev->dev), chip);
620 	if (ret) {
621 		dev_err(&pdev->dev, "Could not request IRQ\n");
622 		return ret;
623 	}
624 
625 	/* clear the alarm counter value */
626 	writel(0, chip->base + SUN6I_ALRM_COUNTER);
627 
628 	/* disable counter alarm */
629 	writel(0, chip->base + SUN6I_ALRM_EN);
630 
631 	/* disable counter alarm interrupt */
632 	writel(0, chip->base + SUN6I_ALRM_IRQ_EN);
633 
634 	/* disable week alarm */
635 	writel(0, chip->base + SUN6I_ALRM1_EN);
636 
637 	/* disable week alarm interrupt */
638 	writel(0, chip->base + SUN6I_ALRM1_IRQ_EN);
639 
640 	/* clear counter alarm pending interrupts */
641 	writel(SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND,
642 	       chip->base + SUN6I_ALRM_IRQ_STA);
643 
644 	/* clear week alarm pending interrupts */
645 	writel(SUN6I_ALRM1_IRQ_STA_WEEK_IRQ_PEND,
646 	       chip->base + SUN6I_ALRM1_IRQ_STA);
647 
648 	/* disable alarm wakeup */
649 	writel(0, chip->base + SUN6I_ALARM_CONFIG);
650 
651 	clk_prepare_enable(chip->losc);
652 
653 	chip->rtc = devm_rtc_device_register(&pdev->dev, "rtc-sun6i",
654 					     &sun6i_rtc_ops, THIS_MODULE);
655 	if (IS_ERR(chip->rtc)) {
656 		dev_err(&pdev->dev, "unable to register device\n");
657 		return PTR_ERR(chip->rtc);
658 	}
659 
660 	dev_info(&pdev->dev, "RTC enabled\n");
661 
662 	return 0;
663 }
664 
665 /*
666  * As far as RTC functionality goes, all models are the same. The
667  * datasheets claim that different models have different number of
668  * registers available for non-volatile storage, but experiments show
669  * that all SoCs have 16 registers available for this purpose.
670  */
671 static const struct of_device_id sun6i_rtc_dt_ids[] = {
672 	{ .compatible = "allwinner,sun6i-a31-rtc" },
673 	{ .compatible = "allwinner,sun8i-a23-rtc" },
674 	{ .compatible = "allwinner,sun8i-h3-rtc" },
675 	{ .compatible = "allwinner,sun8i-r40-rtc" },
676 	{ .compatible = "allwinner,sun8i-v3-rtc" },
677 	{ .compatible = "allwinner,sun50i-h5-rtc" },
678 	{ /* sentinel */ },
679 };
680 MODULE_DEVICE_TABLE(of, sun6i_rtc_dt_ids);
681 
682 static struct platform_driver sun6i_rtc_driver = {
683 	.probe		= sun6i_rtc_probe,
684 	.driver		= {
685 		.name		= "sun6i-rtc",
686 		.of_match_table = sun6i_rtc_dt_ids,
687 	},
688 };
689 builtin_platform_driver(sun6i_rtc_driver);
690