xref: /openbmc/linux/drivers/rtc/rtc-sun6i.c (revision 2cf1c348)
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_OFF				(SUN6I_YEAR_MIN - 1900)
112 
113 /*
114  * There are other differences between models, including:
115  *
116  *   - number of GPIO pins that can be configured to hold a certain level
117  *   - crypto-key related registers (H5, H6)
118  *   - boot process related (super standby, secondary processor entry address)
119  *     registers (R40, H6)
120  *   - SYS power domain controls (R40)
121  *   - DCXO controls (H6)
122  *   - RC oscillator calibration (H6)
123  *
124  * These functions are not covered by this driver.
125  */
126 struct sun6i_rtc_clk_data {
127 	unsigned long rc_osc_rate;
128 	unsigned int fixed_prescaler : 16;
129 	unsigned int has_prescaler : 1;
130 	unsigned int has_out_clk : 1;
131 	unsigned int export_iosc : 1;
132 	unsigned int has_losc_en : 1;
133 	unsigned int has_auto_swt : 1;
134 };
135 
136 struct sun6i_rtc_dev {
137 	struct rtc_device *rtc;
138 	const struct sun6i_rtc_clk_data *data;
139 	void __iomem *base;
140 	int irq;
141 	unsigned long alarm;
142 
143 	struct clk_hw hw;
144 	struct clk_hw *int_osc;
145 	struct clk *losc;
146 	struct clk *ext_losc;
147 
148 	spinlock_t lock;
149 };
150 
151 static struct sun6i_rtc_dev *sun6i_rtc;
152 
153 static unsigned long sun6i_rtc_osc_recalc_rate(struct clk_hw *hw,
154 					       unsigned long parent_rate)
155 {
156 	struct sun6i_rtc_dev *rtc = container_of(hw, struct sun6i_rtc_dev, hw);
157 	u32 val = 0;
158 
159 	val = readl(rtc->base + SUN6I_LOSC_CTRL);
160 	if (val & SUN6I_LOSC_CTRL_EXT_OSC)
161 		return parent_rate;
162 
163 	if (rtc->data->fixed_prescaler)
164 		parent_rate /= rtc->data->fixed_prescaler;
165 
166 	if (rtc->data->has_prescaler) {
167 		val = readl(rtc->base + SUN6I_LOSC_CLK_PRESCAL);
168 		val &= GENMASK(4, 0);
169 	}
170 
171 	return parent_rate / (val + 1);
172 }
173 
174 static u8 sun6i_rtc_osc_get_parent(struct clk_hw *hw)
175 {
176 	struct sun6i_rtc_dev *rtc = container_of(hw, struct sun6i_rtc_dev, hw);
177 
178 	return readl(rtc->base + SUN6I_LOSC_CTRL) & SUN6I_LOSC_CTRL_EXT_OSC;
179 }
180 
181 static int sun6i_rtc_osc_set_parent(struct clk_hw *hw, u8 index)
182 {
183 	struct sun6i_rtc_dev *rtc = container_of(hw, struct sun6i_rtc_dev, hw);
184 	unsigned long flags;
185 	u32 val;
186 
187 	if (index > 1)
188 		return -EINVAL;
189 
190 	spin_lock_irqsave(&rtc->lock, flags);
191 	val = readl(rtc->base + SUN6I_LOSC_CTRL);
192 	val &= ~SUN6I_LOSC_CTRL_EXT_OSC;
193 	val |= SUN6I_LOSC_CTRL_KEY;
194 	val |= index ? SUN6I_LOSC_CTRL_EXT_OSC : 0;
195 	if (rtc->data->has_losc_en) {
196 		val &= ~SUN6I_LOSC_CTRL_EXT_LOSC_EN;
197 		val |= index ? SUN6I_LOSC_CTRL_EXT_LOSC_EN : 0;
198 	}
199 	writel(val, rtc->base + SUN6I_LOSC_CTRL);
200 	spin_unlock_irqrestore(&rtc->lock, flags);
201 
202 	return 0;
203 }
204 
205 static const struct clk_ops sun6i_rtc_osc_ops = {
206 	.recalc_rate	= sun6i_rtc_osc_recalc_rate,
207 
208 	.get_parent	= sun6i_rtc_osc_get_parent,
209 	.set_parent	= sun6i_rtc_osc_set_parent,
210 };
211 
212 static void __init sun6i_rtc_clk_init(struct device_node *node,
213 				      const struct sun6i_rtc_clk_data *data)
214 {
215 	struct clk_hw_onecell_data *clk_data;
216 	struct sun6i_rtc_dev *rtc;
217 	struct clk_init_data init = {
218 		.ops		= &sun6i_rtc_osc_ops,
219 		.name		= "losc",
220 	};
221 	const char *iosc_name = "rtc-int-osc";
222 	const char *clkout_name = "osc32k-out";
223 	const char *parents[2];
224 	u32 reg;
225 
226 	rtc = kzalloc(sizeof(*rtc), GFP_KERNEL);
227 	if (!rtc)
228 		return;
229 
230 	rtc->data = data;
231 	clk_data = kzalloc(struct_size(clk_data, hws, 3), GFP_KERNEL);
232 	if (!clk_data) {
233 		kfree(rtc);
234 		return;
235 	}
236 
237 	spin_lock_init(&rtc->lock);
238 
239 	rtc->base = of_io_request_and_map(node, 0, of_node_full_name(node));
240 	if (IS_ERR(rtc->base)) {
241 		pr_crit("Can't map RTC registers");
242 		goto err;
243 	}
244 
245 	reg = SUN6I_LOSC_CTRL_KEY;
246 	if (rtc->data->has_auto_swt) {
247 		/* Bypass auto-switch to int osc, on ext losc failure */
248 		reg |= SUN6I_LOSC_CTRL_AUTO_SWT_BYPASS;
249 		writel(reg, rtc->base + SUN6I_LOSC_CTRL);
250 	}
251 
252 	/* Switch to the external, more precise, oscillator, if present */
253 	if (of_get_property(node, "clocks", NULL)) {
254 		reg |= SUN6I_LOSC_CTRL_EXT_OSC;
255 		if (rtc->data->has_losc_en)
256 			reg |= SUN6I_LOSC_CTRL_EXT_LOSC_EN;
257 	}
258 	writel(reg, rtc->base + SUN6I_LOSC_CTRL);
259 
260 	/* Yes, I know, this is ugly. */
261 	sun6i_rtc = rtc;
262 
263 	/* Only read IOSC name from device tree if it is exported */
264 	if (rtc->data->export_iosc)
265 		of_property_read_string_index(node, "clock-output-names", 2,
266 					      &iosc_name);
267 
268 	rtc->int_osc = clk_hw_register_fixed_rate_with_accuracy(NULL,
269 								iosc_name,
270 								NULL, 0,
271 								rtc->data->rc_osc_rate,
272 								300000000);
273 	if (IS_ERR(rtc->int_osc)) {
274 		pr_crit("Couldn't register the internal oscillator\n");
275 		goto err;
276 	}
277 
278 	parents[0] = clk_hw_get_name(rtc->int_osc);
279 	/* If there is no external oscillator, this will be NULL and ... */
280 	parents[1] = of_clk_get_parent_name(node, 0);
281 
282 	rtc->hw.init = &init;
283 
284 	init.parent_names = parents;
285 	/* ... number of clock parents will be 1. */
286 	init.num_parents = of_clk_get_parent_count(node) + 1;
287 	of_property_read_string_index(node, "clock-output-names", 0,
288 				      &init.name);
289 
290 	rtc->losc = clk_register(NULL, &rtc->hw);
291 	if (IS_ERR(rtc->losc)) {
292 		pr_crit("Couldn't register the LOSC clock\n");
293 		goto err_register;
294 	}
295 
296 	of_property_read_string_index(node, "clock-output-names", 1,
297 				      &clkout_name);
298 	rtc->ext_losc = clk_register_gate(NULL, clkout_name, init.name,
299 					  0, rtc->base + SUN6I_LOSC_OUT_GATING,
300 					  SUN6I_LOSC_OUT_GATING_EN_OFFSET, 0,
301 					  &rtc->lock);
302 	if (IS_ERR(rtc->ext_losc)) {
303 		pr_crit("Couldn't register the LOSC external gate\n");
304 		goto err_register;
305 	}
306 
307 	clk_data->num = 2;
308 	clk_data->hws[0] = &rtc->hw;
309 	clk_data->hws[1] = __clk_get_hw(rtc->ext_losc);
310 	if (rtc->data->export_iosc) {
311 		clk_data->hws[2] = rtc->int_osc;
312 		clk_data->num = 3;
313 	}
314 	of_clk_add_hw_provider(node, of_clk_hw_onecell_get, clk_data);
315 	return;
316 
317 err_register:
318 	clk_hw_unregister_fixed_rate(rtc->int_osc);
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 /*
384  * The R40 user manual is self-conflicting on whether the prescaler is
385  * fixed or configurable. The clock diagram shows it as fixed, but there
386  * is also a configurable divider in the RTC block.
387  */
388 static const struct sun6i_rtc_clk_data sun8i_r40_rtc_data = {
389 	.rc_osc_rate = 16000000,
390 	.fixed_prescaler = 512,
391 };
392 static void __init sun8i_r40_rtc_clk_init(struct device_node *node)
393 {
394 	sun6i_rtc_clk_init(node, &sun8i_r40_rtc_data);
395 }
396 CLK_OF_DECLARE_DRIVER(sun8i_r40_rtc_clk, "allwinner,sun8i-r40-rtc",
397 		      sun8i_r40_rtc_clk_init);
398 
399 static const struct sun6i_rtc_clk_data sun8i_v3_rtc_data = {
400 	.rc_osc_rate = 32000,
401 	.has_out_clk = 1,
402 };
403 
404 static void __init sun8i_v3_rtc_clk_init(struct device_node *node)
405 {
406 	sun6i_rtc_clk_init(node, &sun8i_v3_rtc_data);
407 }
408 CLK_OF_DECLARE_DRIVER(sun8i_v3_rtc_clk, "allwinner,sun8i-v3-rtc",
409 		      sun8i_v3_rtc_clk_init);
410 
411 static irqreturn_t sun6i_rtc_alarmirq(int irq, void *id)
412 {
413 	struct sun6i_rtc_dev *chip = (struct sun6i_rtc_dev *) id;
414 	irqreturn_t ret = IRQ_NONE;
415 	u32 val;
416 
417 	spin_lock(&chip->lock);
418 	val = readl(chip->base + SUN6I_ALRM_IRQ_STA);
419 
420 	if (val & SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND) {
421 		val |= SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND;
422 		writel(val, chip->base + SUN6I_ALRM_IRQ_STA);
423 
424 		rtc_update_irq(chip->rtc, 1, RTC_AF | RTC_IRQF);
425 
426 		ret = IRQ_HANDLED;
427 	}
428 	spin_unlock(&chip->lock);
429 
430 	return ret;
431 }
432 
433 static void sun6i_rtc_setaie(int to, struct sun6i_rtc_dev *chip)
434 {
435 	u32 alrm_val = 0;
436 	u32 alrm_irq_val = 0;
437 	u32 alrm_wake_val = 0;
438 	unsigned long flags;
439 
440 	if (to) {
441 		alrm_val = SUN6I_ALRM_EN_CNT_EN;
442 		alrm_irq_val = SUN6I_ALRM_IRQ_EN_CNT_IRQ_EN;
443 		alrm_wake_val = SUN6I_ALARM_CONFIG_WAKEUP;
444 	} else {
445 		writel(SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND,
446 		       chip->base + SUN6I_ALRM_IRQ_STA);
447 	}
448 
449 	spin_lock_irqsave(&chip->lock, flags);
450 	writel(alrm_val, chip->base + SUN6I_ALRM_EN);
451 	writel(alrm_irq_val, chip->base + SUN6I_ALRM_IRQ_EN);
452 	writel(alrm_wake_val, chip->base + SUN6I_ALARM_CONFIG);
453 	spin_unlock_irqrestore(&chip->lock, flags);
454 }
455 
456 static int sun6i_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
457 {
458 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
459 	u32 date, time;
460 
461 	/*
462 	 * read again in case it changes
463 	 */
464 	do {
465 		date = readl(chip->base + SUN6I_RTC_YMD);
466 		time = readl(chip->base + SUN6I_RTC_HMS);
467 	} while ((date != readl(chip->base + SUN6I_RTC_YMD)) ||
468 		 (time != readl(chip->base + SUN6I_RTC_HMS)));
469 
470 	rtc_tm->tm_sec  = SUN6I_TIME_GET_SEC_VALUE(time);
471 	rtc_tm->tm_min  = SUN6I_TIME_GET_MIN_VALUE(time);
472 	rtc_tm->tm_hour = SUN6I_TIME_GET_HOUR_VALUE(time);
473 
474 	rtc_tm->tm_mday = SUN6I_DATE_GET_DAY_VALUE(date);
475 	rtc_tm->tm_mon  = SUN6I_DATE_GET_MON_VALUE(date);
476 	rtc_tm->tm_year = SUN6I_DATE_GET_YEAR_VALUE(date);
477 
478 	rtc_tm->tm_mon  -= 1;
479 
480 	/*
481 	 * switch from (data_year->min)-relative offset to
482 	 * a (1900)-relative one
483 	 */
484 	rtc_tm->tm_year += SUN6I_YEAR_OFF;
485 
486 	return 0;
487 }
488 
489 static int sun6i_rtc_getalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
490 {
491 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
492 	unsigned long flags;
493 	u32 alrm_st;
494 	u32 alrm_en;
495 
496 	spin_lock_irqsave(&chip->lock, flags);
497 	alrm_en = readl(chip->base + SUN6I_ALRM_IRQ_EN);
498 	alrm_st = readl(chip->base + SUN6I_ALRM_IRQ_STA);
499 	spin_unlock_irqrestore(&chip->lock, flags);
500 
501 	wkalrm->enabled = !!(alrm_en & SUN6I_ALRM_EN_CNT_EN);
502 	wkalrm->pending = !!(alrm_st & SUN6I_ALRM_EN_CNT_EN);
503 	rtc_time64_to_tm(chip->alarm, &wkalrm->time);
504 
505 	return 0;
506 }
507 
508 static int sun6i_rtc_setalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
509 {
510 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
511 	struct rtc_time *alrm_tm = &wkalrm->time;
512 	struct rtc_time tm_now;
513 	unsigned long time_now = 0;
514 	unsigned long time_set = 0;
515 	unsigned long time_gap = 0;
516 	int ret = 0;
517 
518 	ret = sun6i_rtc_gettime(dev, &tm_now);
519 	if (ret < 0) {
520 		dev_err(dev, "Error in getting time\n");
521 		return -EINVAL;
522 	}
523 
524 	time_set = rtc_tm_to_time64(alrm_tm);
525 	time_now = rtc_tm_to_time64(&tm_now);
526 	if (time_set <= time_now) {
527 		dev_err(dev, "Date to set in the past\n");
528 		return -EINVAL;
529 	}
530 
531 	time_gap = time_set - time_now;
532 
533 	if (time_gap > U32_MAX) {
534 		dev_err(dev, "Date too far in the future\n");
535 		return -EINVAL;
536 	}
537 
538 	sun6i_rtc_setaie(0, chip);
539 	writel(0, chip->base + SUN6I_ALRM_COUNTER);
540 	usleep_range(100, 300);
541 
542 	writel(time_gap, chip->base + SUN6I_ALRM_COUNTER);
543 	chip->alarm = time_set;
544 
545 	sun6i_rtc_setaie(wkalrm->enabled, chip);
546 
547 	return 0;
548 }
549 
550 static int sun6i_rtc_wait(struct sun6i_rtc_dev *chip, int offset,
551 			  unsigned int mask, unsigned int ms_timeout)
552 {
553 	const unsigned long timeout = jiffies + msecs_to_jiffies(ms_timeout);
554 	u32 reg;
555 
556 	do {
557 		reg = readl(chip->base + offset);
558 		reg &= mask;
559 
560 		if (!reg)
561 			return 0;
562 
563 	} while (time_before(jiffies, timeout));
564 
565 	return -ETIMEDOUT;
566 }
567 
568 static int sun6i_rtc_settime(struct device *dev, struct rtc_time *rtc_tm)
569 {
570 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
571 	u32 date = 0;
572 	u32 time = 0;
573 
574 	rtc_tm->tm_year -= SUN6I_YEAR_OFF;
575 	rtc_tm->tm_mon += 1;
576 
577 	date = SUN6I_DATE_SET_DAY_VALUE(rtc_tm->tm_mday) |
578 		SUN6I_DATE_SET_MON_VALUE(rtc_tm->tm_mon)  |
579 		SUN6I_DATE_SET_YEAR_VALUE(rtc_tm->tm_year);
580 
581 	if (is_leap_year(rtc_tm->tm_year + SUN6I_YEAR_MIN))
582 		date |= SUN6I_LEAP_SET_VALUE(1);
583 
584 	time = SUN6I_TIME_SET_SEC_VALUE(rtc_tm->tm_sec)  |
585 		SUN6I_TIME_SET_MIN_VALUE(rtc_tm->tm_min)  |
586 		SUN6I_TIME_SET_HOUR_VALUE(rtc_tm->tm_hour);
587 
588 	/* Check whether registers are writable */
589 	if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
590 			   SUN6I_LOSC_CTRL_ACC_MASK, 50)) {
591 		dev_err(dev, "rtc is still busy.\n");
592 		return -EBUSY;
593 	}
594 
595 	writel(time, chip->base + SUN6I_RTC_HMS);
596 
597 	/*
598 	 * After writing the RTC HH-MM-SS register, the
599 	 * SUN6I_LOSC_CTRL_RTC_HMS_ACC bit is set and it will not
600 	 * be cleared until the real writing operation is finished
601 	 */
602 
603 	if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
604 			   SUN6I_LOSC_CTRL_RTC_HMS_ACC, 50)) {
605 		dev_err(dev, "Failed to set rtc time.\n");
606 		return -ETIMEDOUT;
607 	}
608 
609 	writel(date, chip->base + SUN6I_RTC_YMD);
610 
611 	/*
612 	 * After writing the RTC YY-MM-DD register, the
613 	 * SUN6I_LOSC_CTRL_RTC_YMD_ACC bit is set and it will not
614 	 * be cleared until the real writing operation is finished
615 	 */
616 
617 	if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
618 			   SUN6I_LOSC_CTRL_RTC_YMD_ACC, 50)) {
619 		dev_err(dev, "Failed to set rtc time.\n");
620 		return -ETIMEDOUT;
621 	}
622 
623 	return 0;
624 }
625 
626 static int sun6i_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
627 {
628 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
629 
630 	if (!enabled)
631 		sun6i_rtc_setaie(enabled, chip);
632 
633 	return 0;
634 }
635 
636 static const struct rtc_class_ops sun6i_rtc_ops = {
637 	.read_time		= sun6i_rtc_gettime,
638 	.set_time		= sun6i_rtc_settime,
639 	.read_alarm		= sun6i_rtc_getalarm,
640 	.set_alarm		= sun6i_rtc_setalarm,
641 	.alarm_irq_enable	= sun6i_rtc_alarm_irq_enable
642 };
643 
644 #ifdef CONFIG_PM_SLEEP
645 /* Enable IRQ wake on suspend, to wake up from RTC. */
646 static int sun6i_rtc_suspend(struct device *dev)
647 {
648 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
649 
650 	if (device_may_wakeup(dev))
651 		enable_irq_wake(chip->irq);
652 
653 	return 0;
654 }
655 
656 /* Disable IRQ wake on resume. */
657 static int sun6i_rtc_resume(struct device *dev)
658 {
659 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
660 
661 	if (device_may_wakeup(dev))
662 		disable_irq_wake(chip->irq);
663 
664 	return 0;
665 }
666 #endif
667 
668 static SIMPLE_DEV_PM_OPS(sun6i_rtc_pm_ops,
669 	sun6i_rtc_suspend, sun6i_rtc_resume);
670 
671 static int sun6i_rtc_probe(struct platform_device *pdev)
672 {
673 	struct sun6i_rtc_dev *chip = sun6i_rtc;
674 	int ret;
675 
676 	if (!chip) {
677 		chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
678 		if (!chip)
679 			return -ENOMEM;
680 
681 		spin_lock_init(&chip->lock);
682 
683 		chip->base = devm_platform_ioremap_resource(pdev, 0);
684 		if (IS_ERR(chip->base))
685 			return PTR_ERR(chip->base);
686 	}
687 
688 	platform_set_drvdata(pdev, chip);
689 
690 	chip->irq = platform_get_irq(pdev, 0);
691 	if (chip->irq < 0)
692 		return chip->irq;
693 
694 	ret = devm_request_irq(&pdev->dev, chip->irq, sun6i_rtc_alarmirq,
695 			       0, dev_name(&pdev->dev), chip);
696 	if (ret) {
697 		dev_err(&pdev->dev, "Could not request IRQ\n");
698 		return ret;
699 	}
700 
701 	/* clear the alarm counter value */
702 	writel(0, chip->base + SUN6I_ALRM_COUNTER);
703 
704 	/* disable counter alarm */
705 	writel(0, chip->base + SUN6I_ALRM_EN);
706 
707 	/* disable counter alarm interrupt */
708 	writel(0, chip->base + SUN6I_ALRM_IRQ_EN);
709 
710 	/* disable week alarm */
711 	writel(0, chip->base + SUN6I_ALRM1_EN);
712 
713 	/* disable week alarm interrupt */
714 	writel(0, chip->base + SUN6I_ALRM1_IRQ_EN);
715 
716 	/* clear counter alarm pending interrupts */
717 	writel(SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND,
718 	       chip->base + SUN6I_ALRM_IRQ_STA);
719 
720 	/* clear week alarm pending interrupts */
721 	writel(SUN6I_ALRM1_IRQ_STA_WEEK_IRQ_PEND,
722 	       chip->base + SUN6I_ALRM1_IRQ_STA);
723 
724 	/* disable alarm wakeup */
725 	writel(0, chip->base + SUN6I_ALARM_CONFIG);
726 
727 	clk_prepare_enable(chip->losc);
728 
729 	device_init_wakeup(&pdev->dev, 1);
730 
731 	chip->rtc = devm_rtc_allocate_device(&pdev->dev);
732 	if (IS_ERR(chip->rtc))
733 		return PTR_ERR(chip->rtc);
734 
735 	chip->rtc->ops = &sun6i_rtc_ops;
736 	chip->rtc->range_max = 2019686399LL; /* 2033-12-31 23:59:59 */
737 
738 	ret = devm_rtc_register_device(chip->rtc);
739 	if (ret)
740 		return ret;
741 
742 	dev_info(&pdev->dev, "RTC enabled\n");
743 
744 	return 0;
745 }
746 
747 /*
748  * As far as RTC functionality goes, all models are the same. The
749  * datasheets claim that different models have different number of
750  * registers available for non-volatile storage, but experiments show
751  * that all SoCs have 16 registers available for this purpose.
752  */
753 static const struct of_device_id sun6i_rtc_dt_ids[] = {
754 	{ .compatible = "allwinner,sun6i-a31-rtc" },
755 	{ .compatible = "allwinner,sun8i-a23-rtc" },
756 	{ .compatible = "allwinner,sun8i-h3-rtc" },
757 	{ .compatible = "allwinner,sun8i-r40-rtc" },
758 	{ .compatible = "allwinner,sun8i-v3-rtc" },
759 	{ .compatible = "allwinner,sun50i-h5-rtc" },
760 	{ .compatible = "allwinner,sun50i-h6-rtc" },
761 	{ /* sentinel */ },
762 };
763 MODULE_DEVICE_TABLE(of, sun6i_rtc_dt_ids);
764 
765 static struct platform_driver sun6i_rtc_driver = {
766 	.probe		= sun6i_rtc_probe,
767 	.driver		= {
768 		.name		= "sun6i-rtc",
769 		.of_match_table = sun6i_rtc_dt_ids,
770 		.pm = &sun6i_rtc_pm_ops,
771 	},
772 };
773 builtin_platform_driver(sun6i_rtc_driver);
774