xref: /openbmc/linux/drivers/rtc/rtc-sun6i.c (revision e15a5365)
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 		return;
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 		return;
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 		return;
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:
318 	kfree(clk_data);
319 }
320 
321 static const struct sun6i_rtc_clk_data sun6i_a31_rtc_data = {
322 	.rc_osc_rate = 667000, /* datasheet says 600 ~ 700 KHz */
323 	.has_prescaler = 1,
324 };
325 
326 static void __init sun6i_a31_rtc_clk_init(struct device_node *node)
327 {
328 	sun6i_rtc_clk_init(node, &sun6i_a31_rtc_data);
329 }
330 CLK_OF_DECLARE_DRIVER(sun6i_a31_rtc_clk, "allwinner,sun6i-a31-rtc",
331 		      sun6i_a31_rtc_clk_init);
332 
333 static const struct sun6i_rtc_clk_data sun8i_a23_rtc_data = {
334 	.rc_osc_rate = 667000, /* datasheet says 600 ~ 700 KHz */
335 	.has_prescaler = 1,
336 	.has_out_clk = 1,
337 };
338 
339 static void __init sun8i_a23_rtc_clk_init(struct device_node *node)
340 {
341 	sun6i_rtc_clk_init(node, &sun8i_a23_rtc_data);
342 }
343 CLK_OF_DECLARE_DRIVER(sun8i_a23_rtc_clk, "allwinner,sun8i-a23-rtc",
344 		      sun8i_a23_rtc_clk_init);
345 
346 static const struct sun6i_rtc_clk_data sun8i_h3_rtc_data = {
347 	.rc_osc_rate = 16000000,
348 	.fixed_prescaler = 32,
349 	.has_prescaler = 1,
350 	.has_out_clk = 1,
351 	.export_iosc = 1,
352 };
353 
354 static void __init sun8i_h3_rtc_clk_init(struct device_node *node)
355 {
356 	sun6i_rtc_clk_init(node, &sun8i_h3_rtc_data);
357 }
358 CLK_OF_DECLARE_DRIVER(sun8i_h3_rtc_clk, "allwinner,sun8i-h3-rtc",
359 		      sun8i_h3_rtc_clk_init);
360 /* As far as we are concerned, clocks for H5 are the same as H3 */
361 CLK_OF_DECLARE_DRIVER(sun50i_h5_rtc_clk, "allwinner,sun50i-h5-rtc",
362 		      sun8i_h3_rtc_clk_init);
363 
364 static const struct sun6i_rtc_clk_data sun50i_h6_rtc_data = {
365 	.rc_osc_rate = 16000000,
366 	.fixed_prescaler = 32,
367 	.has_prescaler = 1,
368 	.has_out_clk = 1,
369 	.export_iosc = 1,
370 	.has_losc_en = 1,
371 	.has_auto_swt = 1,
372 };
373 
374 static void __init sun50i_h6_rtc_clk_init(struct device_node *node)
375 {
376 	sun6i_rtc_clk_init(node, &sun50i_h6_rtc_data);
377 }
378 CLK_OF_DECLARE_DRIVER(sun50i_h6_rtc_clk, "allwinner,sun50i-h6-rtc",
379 		      sun50i_h6_rtc_clk_init);
380 
381 /*
382  * The R40 user manual is self-conflicting on whether the prescaler is
383  * fixed or configurable. The clock diagram shows it as fixed, but there
384  * is also a configurable divider in the RTC block.
385  */
386 static const struct sun6i_rtc_clk_data sun8i_r40_rtc_data = {
387 	.rc_osc_rate = 16000000,
388 	.fixed_prescaler = 512,
389 };
390 static void __init sun8i_r40_rtc_clk_init(struct device_node *node)
391 {
392 	sun6i_rtc_clk_init(node, &sun8i_r40_rtc_data);
393 }
394 CLK_OF_DECLARE_DRIVER(sun8i_r40_rtc_clk, "allwinner,sun8i-r40-rtc",
395 		      sun8i_r40_rtc_clk_init);
396 
397 static const struct sun6i_rtc_clk_data sun8i_v3_rtc_data = {
398 	.rc_osc_rate = 32000,
399 	.has_out_clk = 1,
400 };
401 
402 static void __init sun8i_v3_rtc_clk_init(struct device_node *node)
403 {
404 	sun6i_rtc_clk_init(node, &sun8i_v3_rtc_data);
405 }
406 CLK_OF_DECLARE_DRIVER(sun8i_v3_rtc_clk, "allwinner,sun8i-v3-rtc",
407 		      sun8i_v3_rtc_clk_init);
408 
409 static irqreturn_t sun6i_rtc_alarmirq(int irq, void *id)
410 {
411 	struct sun6i_rtc_dev *chip = (struct sun6i_rtc_dev *) id;
412 	irqreturn_t ret = IRQ_NONE;
413 	u32 val;
414 
415 	spin_lock(&chip->lock);
416 	val = readl(chip->base + SUN6I_ALRM_IRQ_STA);
417 
418 	if (val & SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND) {
419 		val |= SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND;
420 		writel(val, chip->base + SUN6I_ALRM_IRQ_STA);
421 
422 		rtc_update_irq(chip->rtc, 1, RTC_AF | RTC_IRQF);
423 
424 		ret = IRQ_HANDLED;
425 	}
426 	spin_unlock(&chip->lock);
427 
428 	return ret;
429 }
430 
431 static void sun6i_rtc_setaie(int to, struct sun6i_rtc_dev *chip)
432 {
433 	u32 alrm_val = 0;
434 	u32 alrm_irq_val = 0;
435 	u32 alrm_wake_val = 0;
436 	unsigned long flags;
437 
438 	if (to) {
439 		alrm_val = SUN6I_ALRM_EN_CNT_EN;
440 		alrm_irq_val = SUN6I_ALRM_IRQ_EN_CNT_IRQ_EN;
441 		alrm_wake_val = SUN6I_ALARM_CONFIG_WAKEUP;
442 	} else {
443 		writel(SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND,
444 		       chip->base + SUN6I_ALRM_IRQ_STA);
445 	}
446 
447 	spin_lock_irqsave(&chip->lock, flags);
448 	writel(alrm_val, chip->base + SUN6I_ALRM_EN);
449 	writel(alrm_irq_val, chip->base + SUN6I_ALRM_IRQ_EN);
450 	writel(alrm_wake_val, chip->base + SUN6I_ALARM_CONFIG);
451 	spin_unlock_irqrestore(&chip->lock, flags);
452 }
453 
454 static int sun6i_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
455 {
456 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
457 	u32 date, time;
458 
459 	/*
460 	 * read again in case it changes
461 	 */
462 	do {
463 		date = readl(chip->base + SUN6I_RTC_YMD);
464 		time = readl(chip->base + SUN6I_RTC_HMS);
465 	} while ((date != readl(chip->base + SUN6I_RTC_YMD)) ||
466 		 (time != readl(chip->base + SUN6I_RTC_HMS)));
467 
468 	rtc_tm->tm_sec  = SUN6I_TIME_GET_SEC_VALUE(time);
469 	rtc_tm->tm_min  = SUN6I_TIME_GET_MIN_VALUE(time);
470 	rtc_tm->tm_hour = SUN6I_TIME_GET_HOUR_VALUE(time);
471 
472 	rtc_tm->tm_mday = SUN6I_DATE_GET_DAY_VALUE(date);
473 	rtc_tm->tm_mon  = SUN6I_DATE_GET_MON_VALUE(date);
474 	rtc_tm->tm_year = SUN6I_DATE_GET_YEAR_VALUE(date);
475 
476 	rtc_tm->tm_mon  -= 1;
477 
478 	/*
479 	 * switch from (data_year->min)-relative offset to
480 	 * a (1900)-relative one
481 	 */
482 	rtc_tm->tm_year += SUN6I_YEAR_OFF;
483 
484 	return 0;
485 }
486 
487 static int sun6i_rtc_getalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
488 {
489 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
490 	unsigned long flags;
491 	u32 alrm_st;
492 	u32 alrm_en;
493 
494 	spin_lock_irqsave(&chip->lock, flags);
495 	alrm_en = readl(chip->base + SUN6I_ALRM_IRQ_EN);
496 	alrm_st = readl(chip->base + SUN6I_ALRM_IRQ_STA);
497 	spin_unlock_irqrestore(&chip->lock, flags);
498 
499 	wkalrm->enabled = !!(alrm_en & SUN6I_ALRM_EN_CNT_EN);
500 	wkalrm->pending = !!(alrm_st & SUN6I_ALRM_EN_CNT_EN);
501 	rtc_time64_to_tm(chip->alarm, &wkalrm->time);
502 
503 	return 0;
504 }
505 
506 static int sun6i_rtc_setalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
507 {
508 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
509 	struct rtc_time *alrm_tm = &wkalrm->time;
510 	struct rtc_time tm_now;
511 	unsigned long time_now = 0;
512 	unsigned long time_set = 0;
513 	unsigned long time_gap = 0;
514 	int ret = 0;
515 
516 	ret = sun6i_rtc_gettime(dev, &tm_now);
517 	if (ret < 0) {
518 		dev_err(dev, "Error in getting time\n");
519 		return -EINVAL;
520 	}
521 
522 	time_set = rtc_tm_to_time64(alrm_tm);
523 	time_now = rtc_tm_to_time64(&tm_now);
524 	if (time_set <= time_now) {
525 		dev_err(dev, "Date to set in the past\n");
526 		return -EINVAL;
527 	}
528 
529 	time_gap = time_set - time_now;
530 
531 	if (time_gap > U32_MAX) {
532 		dev_err(dev, "Date too far in the future\n");
533 		return -EINVAL;
534 	}
535 
536 	sun6i_rtc_setaie(0, chip);
537 	writel(0, chip->base + SUN6I_ALRM_COUNTER);
538 	usleep_range(100, 300);
539 
540 	writel(time_gap, chip->base + SUN6I_ALRM_COUNTER);
541 	chip->alarm = time_set;
542 
543 	sun6i_rtc_setaie(wkalrm->enabled, chip);
544 
545 	return 0;
546 }
547 
548 static int sun6i_rtc_wait(struct sun6i_rtc_dev *chip, int offset,
549 			  unsigned int mask, unsigned int ms_timeout)
550 {
551 	const unsigned long timeout = jiffies + msecs_to_jiffies(ms_timeout);
552 	u32 reg;
553 
554 	do {
555 		reg = readl(chip->base + offset);
556 		reg &= mask;
557 
558 		if (!reg)
559 			return 0;
560 
561 	} while (time_before(jiffies, timeout));
562 
563 	return -ETIMEDOUT;
564 }
565 
566 static int sun6i_rtc_settime(struct device *dev, struct rtc_time *rtc_tm)
567 {
568 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
569 	u32 date = 0;
570 	u32 time = 0;
571 
572 	rtc_tm->tm_year -= SUN6I_YEAR_OFF;
573 	rtc_tm->tm_mon += 1;
574 
575 	date = SUN6I_DATE_SET_DAY_VALUE(rtc_tm->tm_mday) |
576 		SUN6I_DATE_SET_MON_VALUE(rtc_tm->tm_mon)  |
577 		SUN6I_DATE_SET_YEAR_VALUE(rtc_tm->tm_year);
578 
579 	if (is_leap_year(rtc_tm->tm_year + SUN6I_YEAR_MIN))
580 		date |= SUN6I_LEAP_SET_VALUE(1);
581 
582 	time = SUN6I_TIME_SET_SEC_VALUE(rtc_tm->tm_sec)  |
583 		SUN6I_TIME_SET_MIN_VALUE(rtc_tm->tm_min)  |
584 		SUN6I_TIME_SET_HOUR_VALUE(rtc_tm->tm_hour);
585 
586 	/* Check whether registers are writable */
587 	if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
588 			   SUN6I_LOSC_CTRL_ACC_MASK, 50)) {
589 		dev_err(dev, "rtc is still busy.\n");
590 		return -EBUSY;
591 	}
592 
593 	writel(time, chip->base + SUN6I_RTC_HMS);
594 
595 	/*
596 	 * After writing the RTC HH-MM-SS register, the
597 	 * SUN6I_LOSC_CTRL_RTC_HMS_ACC bit is set and it will not
598 	 * be cleared until the real writing operation is finished
599 	 */
600 
601 	if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
602 			   SUN6I_LOSC_CTRL_RTC_HMS_ACC, 50)) {
603 		dev_err(dev, "Failed to set rtc time.\n");
604 		return -ETIMEDOUT;
605 	}
606 
607 	writel(date, chip->base + SUN6I_RTC_YMD);
608 
609 	/*
610 	 * After writing the RTC YY-MM-DD register, the
611 	 * SUN6I_LOSC_CTRL_RTC_YMD_ACC bit is set and it will not
612 	 * be cleared until the real writing operation is finished
613 	 */
614 
615 	if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
616 			   SUN6I_LOSC_CTRL_RTC_YMD_ACC, 50)) {
617 		dev_err(dev, "Failed to set rtc time.\n");
618 		return -ETIMEDOUT;
619 	}
620 
621 	return 0;
622 }
623 
624 static int sun6i_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
625 {
626 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
627 
628 	if (!enabled)
629 		sun6i_rtc_setaie(enabled, chip);
630 
631 	return 0;
632 }
633 
634 static const struct rtc_class_ops sun6i_rtc_ops = {
635 	.read_time		= sun6i_rtc_gettime,
636 	.set_time		= sun6i_rtc_settime,
637 	.read_alarm		= sun6i_rtc_getalarm,
638 	.set_alarm		= sun6i_rtc_setalarm,
639 	.alarm_irq_enable	= sun6i_rtc_alarm_irq_enable
640 };
641 
642 #ifdef CONFIG_PM_SLEEP
643 /* Enable IRQ wake on suspend, to wake up from RTC. */
644 static int sun6i_rtc_suspend(struct device *dev)
645 {
646 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
647 
648 	if (device_may_wakeup(dev))
649 		enable_irq_wake(chip->irq);
650 
651 	return 0;
652 }
653 
654 /* Disable IRQ wake on resume. */
655 static int sun6i_rtc_resume(struct device *dev)
656 {
657 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
658 
659 	if (device_may_wakeup(dev))
660 		disable_irq_wake(chip->irq);
661 
662 	return 0;
663 }
664 #endif
665 
666 static SIMPLE_DEV_PM_OPS(sun6i_rtc_pm_ops,
667 	sun6i_rtc_suspend, sun6i_rtc_resume);
668 
669 static int sun6i_rtc_probe(struct platform_device *pdev)
670 {
671 	struct sun6i_rtc_dev *chip = sun6i_rtc;
672 	int ret;
673 
674 	if (!chip)
675 		return -ENODEV;
676 
677 	platform_set_drvdata(pdev, chip);
678 
679 	chip->irq = platform_get_irq(pdev, 0);
680 	if (chip->irq < 0)
681 		return chip->irq;
682 
683 	ret = devm_request_irq(&pdev->dev, chip->irq, sun6i_rtc_alarmirq,
684 			       0, dev_name(&pdev->dev), chip);
685 	if (ret) {
686 		dev_err(&pdev->dev, "Could not request IRQ\n");
687 		return ret;
688 	}
689 
690 	/* clear the alarm counter value */
691 	writel(0, chip->base + SUN6I_ALRM_COUNTER);
692 
693 	/* disable counter alarm */
694 	writel(0, chip->base + SUN6I_ALRM_EN);
695 
696 	/* disable counter alarm interrupt */
697 	writel(0, chip->base + SUN6I_ALRM_IRQ_EN);
698 
699 	/* disable week alarm */
700 	writel(0, chip->base + SUN6I_ALRM1_EN);
701 
702 	/* disable week alarm interrupt */
703 	writel(0, chip->base + SUN6I_ALRM1_IRQ_EN);
704 
705 	/* clear counter alarm pending interrupts */
706 	writel(SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND,
707 	       chip->base + SUN6I_ALRM_IRQ_STA);
708 
709 	/* clear week alarm pending interrupts */
710 	writel(SUN6I_ALRM1_IRQ_STA_WEEK_IRQ_PEND,
711 	       chip->base + SUN6I_ALRM1_IRQ_STA);
712 
713 	/* disable alarm wakeup */
714 	writel(0, chip->base + SUN6I_ALARM_CONFIG);
715 
716 	clk_prepare_enable(chip->losc);
717 
718 	device_init_wakeup(&pdev->dev, 1);
719 
720 	chip->rtc = devm_rtc_allocate_device(&pdev->dev);
721 	if (IS_ERR(chip->rtc))
722 		return PTR_ERR(chip->rtc);
723 
724 	chip->rtc->ops = &sun6i_rtc_ops;
725 	chip->rtc->range_max = 2019686399LL; /* 2033-12-31 23:59:59 */
726 
727 	ret = rtc_register_device(chip->rtc);
728 	if (ret)
729 		return ret;
730 
731 	dev_info(&pdev->dev, "RTC enabled\n");
732 
733 	return 0;
734 }
735 
736 /*
737  * As far as RTC functionality goes, all models are the same. The
738  * datasheets claim that different models have different number of
739  * registers available for non-volatile storage, but experiments show
740  * that all SoCs have 16 registers available for this purpose.
741  */
742 static const struct of_device_id sun6i_rtc_dt_ids[] = {
743 	{ .compatible = "allwinner,sun6i-a31-rtc" },
744 	{ .compatible = "allwinner,sun8i-a23-rtc" },
745 	{ .compatible = "allwinner,sun8i-h3-rtc" },
746 	{ .compatible = "allwinner,sun8i-r40-rtc" },
747 	{ .compatible = "allwinner,sun8i-v3-rtc" },
748 	{ .compatible = "allwinner,sun50i-h5-rtc" },
749 	{ .compatible = "allwinner,sun50i-h6-rtc" },
750 	{ /* sentinel */ },
751 };
752 MODULE_DEVICE_TABLE(of, sun6i_rtc_dt_ids);
753 
754 static struct platform_driver sun6i_rtc_driver = {
755 	.probe		= sun6i_rtc_probe,
756 	.driver		= {
757 		.name		= "sun6i-rtc",
758 		.of_match_table = sun6i_rtc_dt_ids,
759 		.pm = &sun6i_rtc_pm_ops,
760 	},
761 };
762 builtin_platform_driver(sun6i_rtc_driver);
763