xref: /openbmc/linux/drivers/rtc/rtc-sun6i.c (revision 0a04480d)
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_AUTO_SWT_BYPASS		BIT(15)
36 #define SUN6I_LOSC_CTRL_ALM_DHMS_ACC		BIT(9)
37 #define SUN6I_LOSC_CTRL_RTC_HMS_ACC		BIT(8)
38 #define SUN6I_LOSC_CTRL_RTC_YMD_ACC		BIT(7)
39 #define SUN6I_LOSC_CTRL_EXT_LOSC_EN		BIT(4)
40 #define SUN6I_LOSC_CTRL_EXT_OSC			BIT(0)
41 #define SUN6I_LOSC_CTRL_ACC_MASK		GENMASK(9, 7)
42 
43 #define SUN6I_LOSC_CLK_PRESCAL			0x0008
44 
45 /* RTC */
46 #define SUN6I_RTC_YMD				0x0010
47 #define SUN6I_RTC_HMS				0x0014
48 
49 /* Alarm 0 (counter) */
50 #define SUN6I_ALRM_COUNTER			0x0020
51 #define SUN6I_ALRM_CUR_VAL			0x0024
52 #define SUN6I_ALRM_EN				0x0028
53 #define SUN6I_ALRM_EN_CNT_EN			BIT(0)
54 #define SUN6I_ALRM_IRQ_EN			0x002c
55 #define SUN6I_ALRM_IRQ_EN_CNT_IRQ_EN		BIT(0)
56 #define SUN6I_ALRM_IRQ_STA			0x0030
57 #define SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND		BIT(0)
58 
59 /* Alarm 1 (wall clock) */
60 #define SUN6I_ALRM1_EN				0x0044
61 #define SUN6I_ALRM1_IRQ_EN			0x0048
62 #define SUN6I_ALRM1_IRQ_STA			0x004c
63 #define SUN6I_ALRM1_IRQ_STA_WEEK_IRQ_PEND	BIT(0)
64 
65 /* Alarm config */
66 #define SUN6I_ALARM_CONFIG			0x0050
67 #define SUN6I_ALARM_CONFIG_WAKEUP		BIT(0)
68 
69 #define SUN6I_LOSC_OUT_GATING			0x0060
70 #define SUN6I_LOSC_OUT_GATING_EN_OFFSET		0
71 
72 /*
73  * Get date values
74  */
75 #define SUN6I_DATE_GET_DAY_VALUE(x)		((x)  & 0x0000001f)
76 #define SUN6I_DATE_GET_MON_VALUE(x)		(((x) & 0x00000f00) >> 8)
77 #define SUN6I_DATE_GET_YEAR_VALUE(x)		(((x) & 0x003f0000) >> 16)
78 #define SUN6I_LEAP_GET_VALUE(x)			(((x) & 0x00400000) >> 22)
79 
80 /*
81  * Get time values
82  */
83 #define SUN6I_TIME_GET_SEC_VALUE(x)		((x)  & 0x0000003f)
84 #define SUN6I_TIME_GET_MIN_VALUE(x)		(((x) & 0x00003f00) >> 8)
85 #define SUN6I_TIME_GET_HOUR_VALUE(x)		(((x) & 0x001f0000) >> 16)
86 
87 /*
88  * Set date values
89  */
90 #define SUN6I_DATE_SET_DAY_VALUE(x)		((x)       & 0x0000001f)
91 #define SUN6I_DATE_SET_MON_VALUE(x)		((x) <<  8 & 0x00000f00)
92 #define SUN6I_DATE_SET_YEAR_VALUE(x)		((x) << 16 & 0x003f0000)
93 #define SUN6I_LEAP_SET_VALUE(x)			((x) << 22 & 0x00400000)
94 
95 /*
96  * Set time values
97  */
98 #define SUN6I_TIME_SET_SEC_VALUE(x)		((x)       & 0x0000003f)
99 #define SUN6I_TIME_SET_MIN_VALUE(x)		((x) <<  8 & 0x00003f00)
100 #define SUN6I_TIME_SET_HOUR_VALUE(x)		((x) << 16 & 0x001f0000)
101 
102 /*
103  * The year parameter passed to the driver is usually an offset relative to
104  * the year 1900. This macro is used to convert this offset to another one
105  * relative to the minimum year allowed by the hardware.
106  *
107  * The year range is 1970 - 2033. This range is selected to match Allwinner's
108  * driver, even though it is somewhat limited.
109  */
110 #define SUN6I_YEAR_MIN				1970
111 #define SUN6I_YEAR_MAX				2033
112 #define SUN6I_YEAR_OFF				(SUN6I_YEAR_MIN - 1900)
113 
114 /*
115  * There are other differences between models, including:
116  *
117  *   - number of GPIO pins that can be configured to hold a certain level
118  *   - crypto-key related registers (H5, H6)
119  *   - boot process related (super standby, secondary processor entry address)
120  *     registers (R40, H6)
121  *   - SYS power domain controls (R40)
122  *   - DCXO controls (H6)
123  *   - RC oscillator calibration (H6)
124  *
125  * These functions are not covered by this driver.
126  */
127 struct sun6i_rtc_clk_data {
128 	unsigned long rc_osc_rate;
129 	unsigned int fixed_prescaler : 16;
130 	unsigned int has_prescaler : 1;
131 	unsigned int has_out_clk : 1;
132 	unsigned int export_iosc : 1;
133 	unsigned int has_losc_en : 1;
134 	unsigned int has_auto_swt : 1;
135 };
136 
137 struct sun6i_rtc_dev {
138 	struct rtc_device *rtc;
139 	struct device *dev;
140 	const struct sun6i_rtc_clk_data *data;
141 	void __iomem *base;
142 	int irq;
143 	unsigned long alarm;
144 
145 	struct clk_hw hw;
146 	struct clk_hw *int_osc;
147 	struct clk *losc;
148 	struct clk *ext_losc;
149 
150 	spinlock_t lock;
151 };
152 
153 static struct sun6i_rtc_dev *sun6i_rtc;
154 
155 static unsigned long sun6i_rtc_osc_recalc_rate(struct clk_hw *hw,
156 					       unsigned long parent_rate)
157 {
158 	struct sun6i_rtc_dev *rtc = container_of(hw, struct sun6i_rtc_dev, hw);
159 	u32 val = 0;
160 
161 	val = readl(rtc->base + SUN6I_LOSC_CTRL);
162 	if (val & SUN6I_LOSC_CTRL_EXT_OSC)
163 		return parent_rate;
164 
165 	if (rtc->data->fixed_prescaler)
166 		parent_rate /= rtc->data->fixed_prescaler;
167 
168 	if (rtc->data->has_prescaler) {
169 		val = readl(rtc->base + SUN6I_LOSC_CLK_PRESCAL);
170 		val &= GENMASK(4, 0);
171 	}
172 
173 	return parent_rate / (val + 1);
174 }
175 
176 static u8 sun6i_rtc_osc_get_parent(struct clk_hw *hw)
177 {
178 	struct sun6i_rtc_dev *rtc = container_of(hw, struct sun6i_rtc_dev, hw);
179 
180 	return readl(rtc->base + SUN6I_LOSC_CTRL) & SUN6I_LOSC_CTRL_EXT_OSC;
181 }
182 
183 static int sun6i_rtc_osc_set_parent(struct clk_hw *hw, u8 index)
184 {
185 	struct sun6i_rtc_dev *rtc = container_of(hw, struct sun6i_rtc_dev, hw);
186 	unsigned long flags;
187 	u32 val;
188 
189 	if (index > 1)
190 		return -EINVAL;
191 
192 	spin_lock_irqsave(&rtc->lock, flags);
193 	val = readl(rtc->base + SUN6I_LOSC_CTRL);
194 	val &= ~SUN6I_LOSC_CTRL_EXT_OSC;
195 	val |= SUN6I_LOSC_CTRL_KEY;
196 	val |= index ? SUN6I_LOSC_CTRL_EXT_OSC : 0;
197 	if (rtc->data->has_losc_en) {
198 		val &= ~SUN6I_LOSC_CTRL_EXT_LOSC_EN;
199 		val |= index ? SUN6I_LOSC_CTRL_EXT_LOSC_EN : 0;
200 	}
201 	writel(val, rtc->base + SUN6I_LOSC_CTRL);
202 	spin_unlock_irqrestore(&rtc->lock, flags);
203 
204 	return 0;
205 }
206 
207 static const struct clk_ops sun6i_rtc_osc_ops = {
208 	.recalc_rate	= sun6i_rtc_osc_recalc_rate,
209 
210 	.get_parent	= sun6i_rtc_osc_get_parent,
211 	.set_parent	= sun6i_rtc_osc_set_parent,
212 };
213 
214 static void __init sun6i_rtc_clk_init(struct device_node *node,
215 				      const struct sun6i_rtc_clk_data *data)
216 {
217 	struct clk_hw_onecell_data *clk_data;
218 	struct sun6i_rtc_dev *rtc;
219 	struct clk_init_data init = {
220 		.ops		= &sun6i_rtc_osc_ops,
221 		.name		= "losc",
222 	};
223 	const char *iosc_name = "rtc-int-osc";
224 	const char *clkout_name = "osc32k-out";
225 	const char *parents[2];
226 	u32 reg;
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 	reg = SUN6I_LOSC_CTRL_KEY;
248 	if (rtc->data->has_auto_swt) {
249 		/* Bypass auto-switch to int osc, on ext losc failure */
250 		reg |= SUN6I_LOSC_CTRL_AUTO_SWT_BYPASS;
251 		writel(reg, rtc->base + SUN6I_LOSC_CTRL);
252 	}
253 
254 	/* Switch to the external, more precise, oscillator */
255 	reg |= SUN6I_LOSC_CTRL_EXT_OSC;
256 	if (rtc->data->has_losc_en)
257 		reg |= SUN6I_LOSC_CTRL_EXT_LOSC_EN;
258 	writel(reg, rtc->base + SUN6I_LOSC_CTRL);
259 
260 	/* Yes, I know, this is ugly. */
261 	sun6i_rtc = rtc;
262 
263 	/* Deal with old DTs */
264 	if (!of_get_property(node, "clocks", NULL))
265 		goto err;
266 
267 	/* Only read IOSC name from device tree if it is exported */
268 	if (rtc->data->export_iosc)
269 		of_property_read_string_index(node, "clock-output-names", 2,
270 					      &iosc_name);
271 
272 	rtc->int_osc = clk_hw_register_fixed_rate_with_accuracy(NULL,
273 								iosc_name,
274 								NULL, 0,
275 								rtc->data->rc_osc_rate,
276 								300000000);
277 	if (IS_ERR(rtc->int_osc)) {
278 		pr_crit("Couldn't register the internal oscillator\n");
279 		return;
280 	}
281 
282 	parents[0] = clk_hw_get_name(rtc->int_osc);
283 	parents[1] = of_clk_get_parent_name(node, 0);
284 
285 	rtc->hw.init = &init;
286 
287 	init.parent_names = parents;
288 	init.num_parents = of_clk_get_parent_count(node) + 1;
289 	of_property_read_string_index(node, "clock-output-names", 0,
290 				      &init.name);
291 
292 	rtc->losc = clk_register(NULL, &rtc->hw);
293 	if (IS_ERR(rtc->losc)) {
294 		pr_crit("Couldn't register the LOSC clock\n");
295 		return;
296 	}
297 
298 	of_property_read_string_index(node, "clock-output-names", 1,
299 				      &clkout_name);
300 	rtc->ext_losc = clk_register_gate(NULL, clkout_name, init.name,
301 					  0, rtc->base + SUN6I_LOSC_OUT_GATING,
302 					  SUN6I_LOSC_OUT_GATING_EN_OFFSET, 0,
303 					  &rtc->lock);
304 	if (IS_ERR(rtc->ext_losc)) {
305 		pr_crit("Couldn't register the LOSC external gate\n");
306 		return;
307 	}
308 
309 	clk_data->num = 2;
310 	clk_data->hws[0] = &rtc->hw;
311 	clk_data->hws[1] = __clk_get_hw(rtc->ext_losc);
312 	if (rtc->data->export_iosc) {
313 		clk_data->hws[2] = rtc->int_osc;
314 		clk_data->num = 3;
315 	}
316 	of_clk_add_hw_provider(node, of_clk_hw_onecell_get, clk_data);
317 	return;
318 
319 err:
320 	kfree(clk_data);
321 }
322 
323 static const struct sun6i_rtc_clk_data sun6i_a31_rtc_data = {
324 	.rc_osc_rate = 667000, /* datasheet says 600 ~ 700 KHz */
325 	.has_prescaler = 1,
326 };
327 
328 static void __init sun6i_a31_rtc_clk_init(struct device_node *node)
329 {
330 	sun6i_rtc_clk_init(node, &sun6i_a31_rtc_data);
331 }
332 CLK_OF_DECLARE_DRIVER(sun6i_a31_rtc_clk, "allwinner,sun6i-a31-rtc",
333 		      sun6i_a31_rtc_clk_init);
334 
335 static const struct sun6i_rtc_clk_data sun8i_a23_rtc_data = {
336 	.rc_osc_rate = 667000, /* datasheet says 600 ~ 700 KHz */
337 	.has_prescaler = 1,
338 	.has_out_clk = 1,
339 };
340 
341 static void __init sun8i_a23_rtc_clk_init(struct device_node *node)
342 {
343 	sun6i_rtc_clk_init(node, &sun8i_a23_rtc_data);
344 }
345 CLK_OF_DECLARE_DRIVER(sun8i_a23_rtc_clk, "allwinner,sun8i-a23-rtc",
346 		      sun8i_a23_rtc_clk_init);
347 
348 static const struct sun6i_rtc_clk_data sun8i_h3_rtc_data = {
349 	.rc_osc_rate = 16000000,
350 	.fixed_prescaler = 32,
351 	.has_prescaler = 1,
352 	.has_out_clk = 1,
353 	.export_iosc = 1,
354 };
355 
356 static void __init sun8i_h3_rtc_clk_init(struct device_node *node)
357 {
358 	sun6i_rtc_clk_init(node, &sun8i_h3_rtc_data);
359 }
360 CLK_OF_DECLARE_DRIVER(sun8i_h3_rtc_clk, "allwinner,sun8i-h3-rtc",
361 		      sun8i_h3_rtc_clk_init);
362 /* As far as we are concerned, clocks for H5 are the same as H3 */
363 CLK_OF_DECLARE_DRIVER(sun50i_h5_rtc_clk, "allwinner,sun50i-h5-rtc",
364 		      sun8i_h3_rtc_clk_init);
365 
366 static const struct sun6i_rtc_clk_data sun50i_h6_rtc_data = {
367 	.rc_osc_rate = 16000000,
368 	.fixed_prescaler = 32,
369 	.has_prescaler = 1,
370 	.has_out_clk = 1,
371 	.export_iosc = 1,
372 	.has_losc_en = 1,
373 	.has_auto_swt = 1,
374 };
375 
376 static void __init sun50i_h6_rtc_clk_init(struct device_node *node)
377 {
378 	sun6i_rtc_clk_init(node, &sun50i_h6_rtc_data);
379 }
380 CLK_OF_DECLARE_DRIVER(sun50i_h6_rtc_clk, "allwinner,sun50i-h6-rtc",
381 		      sun50i_h6_rtc_clk_init);
382 
383 static const struct sun6i_rtc_clk_data sun8i_v3_rtc_data = {
384 	.rc_osc_rate = 32000,
385 	.has_out_clk = 1,
386 };
387 
388 static void __init sun8i_v3_rtc_clk_init(struct device_node *node)
389 {
390 	sun6i_rtc_clk_init(node, &sun8i_v3_rtc_data);
391 }
392 CLK_OF_DECLARE_DRIVER(sun8i_v3_rtc_clk, "allwinner,sun8i-v3-rtc",
393 		      sun8i_v3_rtc_clk_init);
394 
395 static irqreturn_t sun6i_rtc_alarmirq(int irq, void *id)
396 {
397 	struct sun6i_rtc_dev *chip = (struct sun6i_rtc_dev *) id;
398 	irqreturn_t ret = IRQ_NONE;
399 	u32 val;
400 
401 	spin_lock(&chip->lock);
402 	val = readl(chip->base + SUN6I_ALRM_IRQ_STA);
403 
404 	if (val & SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND) {
405 		val |= SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND;
406 		writel(val, chip->base + SUN6I_ALRM_IRQ_STA);
407 
408 		rtc_update_irq(chip->rtc, 1, RTC_AF | RTC_IRQF);
409 
410 		ret = IRQ_HANDLED;
411 	}
412 	spin_unlock(&chip->lock);
413 
414 	return ret;
415 }
416 
417 static void sun6i_rtc_setaie(int to, struct sun6i_rtc_dev *chip)
418 {
419 	u32 alrm_val = 0;
420 	u32 alrm_irq_val = 0;
421 	u32 alrm_wake_val = 0;
422 	unsigned long flags;
423 
424 	if (to) {
425 		alrm_val = SUN6I_ALRM_EN_CNT_EN;
426 		alrm_irq_val = SUN6I_ALRM_IRQ_EN_CNT_IRQ_EN;
427 		alrm_wake_val = SUN6I_ALARM_CONFIG_WAKEUP;
428 	} else {
429 		writel(SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND,
430 		       chip->base + SUN6I_ALRM_IRQ_STA);
431 	}
432 
433 	spin_lock_irqsave(&chip->lock, flags);
434 	writel(alrm_val, chip->base + SUN6I_ALRM_EN);
435 	writel(alrm_irq_val, chip->base + SUN6I_ALRM_IRQ_EN);
436 	writel(alrm_wake_val, chip->base + SUN6I_ALARM_CONFIG);
437 	spin_unlock_irqrestore(&chip->lock, flags);
438 }
439 
440 static int sun6i_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
441 {
442 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
443 	u32 date, time;
444 
445 	/*
446 	 * read again in case it changes
447 	 */
448 	do {
449 		date = readl(chip->base + SUN6I_RTC_YMD);
450 		time = readl(chip->base + SUN6I_RTC_HMS);
451 	} while ((date != readl(chip->base + SUN6I_RTC_YMD)) ||
452 		 (time != readl(chip->base + SUN6I_RTC_HMS)));
453 
454 	rtc_tm->tm_sec  = SUN6I_TIME_GET_SEC_VALUE(time);
455 	rtc_tm->tm_min  = SUN6I_TIME_GET_MIN_VALUE(time);
456 	rtc_tm->tm_hour = SUN6I_TIME_GET_HOUR_VALUE(time);
457 
458 	rtc_tm->tm_mday = SUN6I_DATE_GET_DAY_VALUE(date);
459 	rtc_tm->tm_mon  = SUN6I_DATE_GET_MON_VALUE(date);
460 	rtc_tm->tm_year = SUN6I_DATE_GET_YEAR_VALUE(date);
461 
462 	rtc_tm->tm_mon  -= 1;
463 
464 	/*
465 	 * switch from (data_year->min)-relative offset to
466 	 * a (1900)-relative one
467 	 */
468 	rtc_tm->tm_year += SUN6I_YEAR_OFF;
469 
470 	return 0;
471 }
472 
473 static int sun6i_rtc_getalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
474 {
475 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
476 	unsigned long flags;
477 	u32 alrm_st;
478 	u32 alrm_en;
479 
480 	spin_lock_irqsave(&chip->lock, flags);
481 	alrm_en = readl(chip->base + SUN6I_ALRM_IRQ_EN);
482 	alrm_st = readl(chip->base + SUN6I_ALRM_IRQ_STA);
483 	spin_unlock_irqrestore(&chip->lock, flags);
484 
485 	wkalrm->enabled = !!(alrm_en & SUN6I_ALRM_EN_CNT_EN);
486 	wkalrm->pending = !!(alrm_st & SUN6I_ALRM_EN_CNT_EN);
487 	rtc_time_to_tm(chip->alarm, &wkalrm->time);
488 
489 	return 0;
490 }
491 
492 static int sun6i_rtc_setalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
493 {
494 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
495 	struct rtc_time *alrm_tm = &wkalrm->time;
496 	struct rtc_time tm_now;
497 	unsigned long time_now = 0;
498 	unsigned long time_set = 0;
499 	unsigned long time_gap = 0;
500 	int ret = 0;
501 
502 	ret = sun6i_rtc_gettime(dev, &tm_now);
503 	if (ret < 0) {
504 		dev_err(dev, "Error in getting time\n");
505 		return -EINVAL;
506 	}
507 
508 	rtc_tm_to_time(alrm_tm, &time_set);
509 	rtc_tm_to_time(&tm_now, &time_now);
510 	if (time_set <= time_now) {
511 		dev_err(dev, "Date to set in the past\n");
512 		return -EINVAL;
513 	}
514 
515 	time_gap = time_set - time_now;
516 
517 	if (time_gap > U32_MAX) {
518 		dev_err(dev, "Date too far in the future\n");
519 		return -EINVAL;
520 	}
521 
522 	sun6i_rtc_setaie(0, chip);
523 	writel(0, chip->base + SUN6I_ALRM_COUNTER);
524 	usleep_range(100, 300);
525 
526 	writel(time_gap, chip->base + SUN6I_ALRM_COUNTER);
527 	chip->alarm = time_set;
528 
529 	sun6i_rtc_setaie(wkalrm->enabled, chip);
530 
531 	return 0;
532 }
533 
534 static int sun6i_rtc_wait(struct sun6i_rtc_dev *chip, int offset,
535 			  unsigned int mask, unsigned int ms_timeout)
536 {
537 	const unsigned long timeout = jiffies + msecs_to_jiffies(ms_timeout);
538 	u32 reg;
539 
540 	do {
541 		reg = readl(chip->base + offset);
542 		reg &= mask;
543 
544 		if (!reg)
545 			return 0;
546 
547 	} while (time_before(jiffies, timeout));
548 
549 	return -ETIMEDOUT;
550 }
551 
552 static int sun6i_rtc_settime(struct device *dev, struct rtc_time *rtc_tm)
553 {
554 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
555 	u32 date = 0;
556 	u32 time = 0;
557 	int year;
558 
559 	year = rtc_tm->tm_year + 1900;
560 	if (year < SUN6I_YEAR_MIN || year > SUN6I_YEAR_MAX) {
561 		dev_err(dev, "rtc only supports year in range %d - %d\n",
562 			SUN6I_YEAR_MIN, SUN6I_YEAR_MAX);
563 		return -EINVAL;
564 	}
565 
566 	rtc_tm->tm_year -= SUN6I_YEAR_OFF;
567 	rtc_tm->tm_mon += 1;
568 
569 	date = SUN6I_DATE_SET_DAY_VALUE(rtc_tm->tm_mday) |
570 		SUN6I_DATE_SET_MON_VALUE(rtc_tm->tm_mon)  |
571 		SUN6I_DATE_SET_YEAR_VALUE(rtc_tm->tm_year);
572 
573 	if (is_leap_year(year))
574 		date |= SUN6I_LEAP_SET_VALUE(1);
575 
576 	time = SUN6I_TIME_SET_SEC_VALUE(rtc_tm->tm_sec)  |
577 		SUN6I_TIME_SET_MIN_VALUE(rtc_tm->tm_min)  |
578 		SUN6I_TIME_SET_HOUR_VALUE(rtc_tm->tm_hour);
579 
580 	/* Check whether registers are writable */
581 	if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
582 			   SUN6I_LOSC_CTRL_ACC_MASK, 50)) {
583 		dev_err(dev, "rtc is still busy.\n");
584 		return -EBUSY;
585 	}
586 
587 	writel(time, chip->base + SUN6I_RTC_HMS);
588 
589 	/*
590 	 * After writing the RTC HH-MM-SS register, the
591 	 * SUN6I_LOSC_CTRL_RTC_HMS_ACC bit is set and it will not
592 	 * be cleared until the real writing operation is finished
593 	 */
594 
595 	if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
596 			   SUN6I_LOSC_CTRL_RTC_HMS_ACC, 50)) {
597 		dev_err(dev, "Failed to set rtc time.\n");
598 		return -ETIMEDOUT;
599 	}
600 
601 	writel(date, chip->base + SUN6I_RTC_YMD);
602 
603 	/*
604 	 * After writing the RTC YY-MM-DD register, the
605 	 * SUN6I_LOSC_CTRL_RTC_YMD_ACC bit is set and it will not
606 	 * be cleared until the real writing operation is finished
607 	 */
608 
609 	if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
610 			   SUN6I_LOSC_CTRL_RTC_YMD_ACC, 50)) {
611 		dev_err(dev, "Failed to set rtc time.\n");
612 		return -ETIMEDOUT;
613 	}
614 
615 	return 0;
616 }
617 
618 static int sun6i_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
619 {
620 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
621 
622 	if (!enabled)
623 		sun6i_rtc_setaie(enabled, chip);
624 
625 	return 0;
626 }
627 
628 static const struct rtc_class_ops sun6i_rtc_ops = {
629 	.read_time		= sun6i_rtc_gettime,
630 	.set_time		= sun6i_rtc_settime,
631 	.read_alarm		= sun6i_rtc_getalarm,
632 	.set_alarm		= sun6i_rtc_setalarm,
633 	.alarm_irq_enable	= sun6i_rtc_alarm_irq_enable
634 };
635 
636 #ifdef CONFIG_PM_SLEEP
637 /* Enable IRQ wake on suspend, to wake up from RTC. */
638 static int sun6i_rtc_suspend(struct device *dev)
639 {
640 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
641 
642 	if (device_may_wakeup(dev))
643 		enable_irq_wake(chip->irq);
644 
645 	return 0;
646 }
647 
648 /* Disable IRQ wake on resume. */
649 static int sun6i_rtc_resume(struct device *dev)
650 {
651 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
652 
653 	if (device_may_wakeup(dev))
654 		disable_irq_wake(chip->irq);
655 
656 	return 0;
657 }
658 #endif
659 
660 static SIMPLE_DEV_PM_OPS(sun6i_rtc_pm_ops,
661 	sun6i_rtc_suspend, sun6i_rtc_resume);
662 
663 static int sun6i_rtc_probe(struct platform_device *pdev)
664 {
665 	struct sun6i_rtc_dev *chip = sun6i_rtc;
666 	int ret;
667 
668 	if (!chip)
669 		return -ENODEV;
670 
671 	platform_set_drvdata(pdev, chip);
672 	chip->dev = &pdev->dev;
673 
674 	chip->irq = platform_get_irq(pdev, 0);
675 	if (chip->irq < 0)
676 		return chip->irq;
677 
678 	ret = devm_request_irq(&pdev->dev, chip->irq, sun6i_rtc_alarmirq,
679 			       0, dev_name(&pdev->dev), chip);
680 	if (ret) {
681 		dev_err(&pdev->dev, "Could not request IRQ\n");
682 		return ret;
683 	}
684 
685 	/* clear the alarm counter value */
686 	writel(0, chip->base + SUN6I_ALRM_COUNTER);
687 
688 	/* disable counter alarm */
689 	writel(0, chip->base + SUN6I_ALRM_EN);
690 
691 	/* disable counter alarm interrupt */
692 	writel(0, chip->base + SUN6I_ALRM_IRQ_EN);
693 
694 	/* disable week alarm */
695 	writel(0, chip->base + SUN6I_ALRM1_EN);
696 
697 	/* disable week alarm interrupt */
698 	writel(0, chip->base + SUN6I_ALRM1_IRQ_EN);
699 
700 	/* clear counter alarm pending interrupts */
701 	writel(SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND,
702 	       chip->base + SUN6I_ALRM_IRQ_STA);
703 
704 	/* clear week alarm pending interrupts */
705 	writel(SUN6I_ALRM1_IRQ_STA_WEEK_IRQ_PEND,
706 	       chip->base + SUN6I_ALRM1_IRQ_STA);
707 
708 	/* disable alarm wakeup */
709 	writel(0, chip->base + SUN6I_ALARM_CONFIG);
710 
711 	clk_prepare_enable(chip->losc);
712 
713 	device_init_wakeup(&pdev->dev, 1);
714 
715 	chip->rtc = devm_rtc_device_register(&pdev->dev, "rtc-sun6i",
716 					     &sun6i_rtc_ops, THIS_MODULE);
717 	if (IS_ERR(chip->rtc)) {
718 		dev_err(&pdev->dev, "unable to register device\n");
719 		return PTR_ERR(chip->rtc);
720 	}
721 
722 	dev_info(&pdev->dev, "RTC enabled\n");
723 
724 	return 0;
725 }
726 
727 /*
728  * As far as RTC functionality goes, all models are the same. The
729  * datasheets claim that different models have different number of
730  * registers available for non-volatile storage, but experiments show
731  * that all SoCs have 16 registers available for this purpose.
732  */
733 static const struct of_device_id sun6i_rtc_dt_ids[] = {
734 	{ .compatible = "allwinner,sun6i-a31-rtc" },
735 	{ .compatible = "allwinner,sun8i-a23-rtc" },
736 	{ .compatible = "allwinner,sun8i-h3-rtc" },
737 	{ .compatible = "allwinner,sun8i-r40-rtc" },
738 	{ .compatible = "allwinner,sun8i-v3-rtc" },
739 	{ .compatible = "allwinner,sun50i-h5-rtc" },
740 	{ .compatible = "allwinner,sun50i-h6-rtc" },
741 	{ /* sentinel */ },
742 };
743 MODULE_DEVICE_TABLE(of, sun6i_rtc_dt_ids);
744 
745 static struct platform_driver sun6i_rtc_driver = {
746 	.probe		= sun6i_rtc_probe,
747 	.driver		= {
748 		.name		= "sun6i-rtc",
749 		.of_match_table = sun6i_rtc_dt_ids,
750 		.pm = &sun6i_rtc_pm_ops,
751 	},
752 };
753 builtin_platform_driver(sun6i_rtc_driver);
754