xref: /openbmc/linux/drivers/rtc/rtc-sun6i.c (revision dc6a81c3)
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 	const struct sun6i_rtc_clk_data *data;
140 	void __iomem *base;
141 	int irq;
142 	unsigned long alarm;
143 
144 	struct clk_hw hw;
145 	struct clk_hw *int_osc;
146 	struct clk *losc;
147 	struct clk *ext_losc;
148 
149 	spinlock_t lock;
150 };
151 
152 static struct sun6i_rtc_dev *sun6i_rtc;
153 
154 static unsigned long sun6i_rtc_osc_recalc_rate(struct clk_hw *hw,
155 					       unsigned long parent_rate)
156 {
157 	struct sun6i_rtc_dev *rtc = container_of(hw, struct sun6i_rtc_dev, hw);
158 	u32 val = 0;
159 
160 	val = readl(rtc->base + SUN6I_LOSC_CTRL);
161 	if (val & SUN6I_LOSC_CTRL_EXT_OSC)
162 		return parent_rate;
163 
164 	if (rtc->data->fixed_prescaler)
165 		parent_rate /= rtc->data->fixed_prescaler;
166 
167 	if (rtc->data->has_prescaler) {
168 		val = readl(rtc->base + SUN6I_LOSC_CLK_PRESCAL);
169 		val &= GENMASK(4, 0);
170 	}
171 
172 	return parent_rate / (val + 1);
173 }
174 
175 static u8 sun6i_rtc_osc_get_parent(struct clk_hw *hw)
176 {
177 	struct sun6i_rtc_dev *rtc = container_of(hw, struct sun6i_rtc_dev, hw);
178 
179 	return readl(rtc->base + SUN6I_LOSC_CTRL) & SUN6I_LOSC_CTRL_EXT_OSC;
180 }
181 
182 static int sun6i_rtc_osc_set_parent(struct clk_hw *hw, u8 index)
183 {
184 	struct sun6i_rtc_dev *rtc = container_of(hw, struct sun6i_rtc_dev, hw);
185 	unsigned long flags;
186 	u32 val;
187 
188 	if (index > 1)
189 		return -EINVAL;
190 
191 	spin_lock_irqsave(&rtc->lock, flags);
192 	val = readl(rtc->base + SUN6I_LOSC_CTRL);
193 	val &= ~SUN6I_LOSC_CTRL_EXT_OSC;
194 	val |= SUN6I_LOSC_CTRL_KEY;
195 	val |= index ? SUN6I_LOSC_CTRL_EXT_OSC : 0;
196 	if (rtc->data->has_losc_en) {
197 		val &= ~SUN6I_LOSC_CTRL_EXT_LOSC_EN;
198 		val |= index ? SUN6I_LOSC_CTRL_EXT_LOSC_EN : 0;
199 	}
200 	writel(val, rtc->base + SUN6I_LOSC_CTRL);
201 	spin_unlock_irqrestore(&rtc->lock, flags);
202 
203 	return 0;
204 }
205 
206 static const struct clk_ops sun6i_rtc_osc_ops = {
207 	.recalc_rate	= sun6i_rtc_osc_recalc_rate,
208 
209 	.get_parent	= sun6i_rtc_osc_get_parent,
210 	.set_parent	= sun6i_rtc_osc_set_parent,
211 };
212 
213 static void __init sun6i_rtc_clk_init(struct device_node *node,
214 				      const struct sun6i_rtc_clk_data *data)
215 {
216 	struct clk_hw_onecell_data *clk_data;
217 	struct sun6i_rtc_dev *rtc;
218 	struct clk_init_data init = {
219 		.ops		= &sun6i_rtc_osc_ops,
220 		.name		= "losc",
221 	};
222 	const char *iosc_name = "rtc-int-osc";
223 	const char *clkout_name = "osc32k-out";
224 	const char *parents[2];
225 	u32 reg;
226 
227 	rtc = kzalloc(sizeof(*rtc), GFP_KERNEL);
228 	if (!rtc)
229 		return;
230 
231 	rtc->data = data;
232 	clk_data = kzalloc(struct_size(clk_data, hws, 3), GFP_KERNEL);
233 	if (!clk_data) {
234 		kfree(rtc);
235 		return;
236 	}
237 
238 	spin_lock_init(&rtc->lock);
239 
240 	rtc->base = of_io_request_and_map(node, 0, of_node_full_name(node));
241 	if (IS_ERR(rtc->base)) {
242 		pr_crit("Can't map RTC registers");
243 		goto err;
244 	}
245 
246 	reg = SUN6I_LOSC_CTRL_KEY;
247 	if (rtc->data->has_auto_swt) {
248 		/* Bypass auto-switch to int osc, on ext losc failure */
249 		reg |= SUN6I_LOSC_CTRL_AUTO_SWT_BYPASS;
250 		writel(reg, rtc->base + SUN6I_LOSC_CTRL);
251 	}
252 
253 	/* Switch to the external, more precise, oscillator */
254 	reg |= SUN6I_LOSC_CTRL_EXT_OSC;
255 	if (rtc->data->has_losc_en)
256 		reg |= SUN6I_LOSC_CTRL_EXT_LOSC_EN;
257 	writel(reg, rtc->base + SUN6I_LOSC_CTRL);
258 
259 	/* Yes, I know, this is ugly. */
260 	sun6i_rtc = rtc;
261 
262 	/* Deal with old DTs */
263 	if (!of_get_property(node, "clocks", NULL))
264 		goto err;
265 
266 	/* Only read IOSC name from device tree if it is exported */
267 	if (rtc->data->export_iosc)
268 		of_property_read_string_index(node, "clock-output-names", 2,
269 					      &iosc_name);
270 
271 	rtc->int_osc = clk_hw_register_fixed_rate_with_accuracy(NULL,
272 								iosc_name,
273 								NULL, 0,
274 								rtc->data->rc_osc_rate,
275 								300000000);
276 	if (IS_ERR(rtc->int_osc)) {
277 		pr_crit("Couldn't register the internal oscillator\n");
278 		return;
279 	}
280 
281 	parents[0] = clk_hw_get_name(rtc->int_osc);
282 	parents[1] = of_clk_get_parent_name(node, 0);
283 
284 	rtc->hw.init = &init;
285 
286 	init.parent_names = parents;
287 	init.num_parents = of_clk_get_parent_count(node) + 1;
288 	of_property_read_string_index(node, "clock-output-names", 0,
289 				      &init.name);
290 
291 	rtc->losc = clk_register(NULL, &rtc->hw);
292 	if (IS_ERR(rtc->losc)) {
293 		pr_crit("Couldn't register the LOSC clock\n");
294 		return;
295 	}
296 
297 	of_property_read_string_index(node, "clock-output-names", 1,
298 				      &clkout_name);
299 	rtc->ext_losc = clk_register_gate(NULL, clkout_name, init.name,
300 					  0, rtc->base + SUN6I_LOSC_OUT_GATING,
301 					  SUN6I_LOSC_OUT_GATING_EN_OFFSET, 0,
302 					  &rtc->lock);
303 	if (IS_ERR(rtc->ext_losc)) {
304 		pr_crit("Couldn't register the LOSC external gate\n");
305 		return;
306 	}
307 
308 	clk_data->num = 2;
309 	clk_data->hws[0] = &rtc->hw;
310 	clk_data->hws[1] = __clk_get_hw(rtc->ext_losc);
311 	if (rtc->data->export_iosc) {
312 		clk_data->hws[2] = rtc->int_osc;
313 		clk_data->num = 3;
314 	}
315 	of_clk_add_hw_provider(node, of_clk_hw_onecell_get, clk_data);
316 	return;
317 
318 err:
319 	kfree(clk_data);
320 }
321 
322 static const struct sun6i_rtc_clk_data sun6i_a31_rtc_data = {
323 	.rc_osc_rate = 667000, /* datasheet says 600 ~ 700 KHz */
324 	.has_prescaler = 1,
325 };
326 
327 static void __init sun6i_a31_rtc_clk_init(struct device_node *node)
328 {
329 	sun6i_rtc_clk_init(node, &sun6i_a31_rtc_data);
330 }
331 CLK_OF_DECLARE_DRIVER(sun6i_a31_rtc_clk, "allwinner,sun6i-a31-rtc",
332 		      sun6i_a31_rtc_clk_init);
333 
334 static const struct sun6i_rtc_clk_data sun8i_a23_rtc_data = {
335 	.rc_osc_rate = 667000, /* datasheet says 600 ~ 700 KHz */
336 	.has_prescaler = 1,
337 	.has_out_clk = 1,
338 };
339 
340 static void __init sun8i_a23_rtc_clk_init(struct device_node *node)
341 {
342 	sun6i_rtc_clk_init(node, &sun8i_a23_rtc_data);
343 }
344 CLK_OF_DECLARE_DRIVER(sun8i_a23_rtc_clk, "allwinner,sun8i-a23-rtc",
345 		      sun8i_a23_rtc_clk_init);
346 
347 static const struct sun6i_rtc_clk_data sun8i_h3_rtc_data = {
348 	.rc_osc_rate = 16000000,
349 	.fixed_prescaler = 32,
350 	.has_prescaler = 1,
351 	.has_out_clk = 1,
352 	.export_iosc = 1,
353 };
354 
355 static void __init sun8i_h3_rtc_clk_init(struct device_node *node)
356 {
357 	sun6i_rtc_clk_init(node, &sun8i_h3_rtc_data);
358 }
359 CLK_OF_DECLARE_DRIVER(sun8i_h3_rtc_clk, "allwinner,sun8i-h3-rtc",
360 		      sun8i_h3_rtc_clk_init);
361 /* As far as we are concerned, clocks for H5 are the same as H3 */
362 CLK_OF_DECLARE_DRIVER(sun50i_h5_rtc_clk, "allwinner,sun50i-h5-rtc",
363 		      sun8i_h3_rtc_clk_init);
364 
365 static const struct sun6i_rtc_clk_data sun50i_h6_rtc_data = {
366 	.rc_osc_rate = 16000000,
367 	.fixed_prescaler = 32,
368 	.has_prescaler = 1,
369 	.has_out_clk = 1,
370 	.export_iosc = 1,
371 	.has_losc_en = 1,
372 	.has_auto_swt = 1,
373 };
374 
375 static void __init sun50i_h6_rtc_clk_init(struct device_node *node)
376 {
377 	sun6i_rtc_clk_init(node, &sun50i_h6_rtc_data);
378 }
379 CLK_OF_DECLARE_DRIVER(sun50i_h6_rtc_clk, "allwinner,sun50i-h6-rtc",
380 		      sun50i_h6_rtc_clk_init);
381 
382 /*
383  * The R40 user manual is self-conflicting on whether the prescaler is
384  * fixed or configurable. The clock diagram shows it as fixed, but there
385  * is also a configurable divider in the RTC block.
386  */
387 static const struct sun6i_rtc_clk_data sun8i_r40_rtc_data = {
388 	.rc_osc_rate = 16000000,
389 	.fixed_prescaler = 512,
390 };
391 static void __init sun8i_r40_rtc_clk_init(struct device_node *node)
392 {
393 	sun6i_rtc_clk_init(node, &sun8i_r40_rtc_data);
394 }
395 CLK_OF_DECLARE_DRIVER(sun8i_r40_rtc_clk, "allwinner,sun8i-r40-rtc",
396 		      sun8i_r40_rtc_clk_init);
397 
398 static const struct sun6i_rtc_clk_data sun8i_v3_rtc_data = {
399 	.rc_osc_rate = 32000,
400 	.has_out_clk = 1,
401 };
402 
403 static void __init sun8i_v3_rtc_clk_init(struct device_node *node)
404 {
405 	sun6i_rtc_clk_init(node, &sun8i_v3_rtc_data);
406 }
407 CLK_OF_DECLARE_DRIVER(sun8i_v3_rtc_clk, "allwinner,sun8i-v3-rtc",
408 		      sun8i_v3_rtc_clk_init);
409 
410 static irqreturn_t sun6i_rtc_alarmirq(int irq, void *id)
411 {
412 	struct sun6i_rtc_dev *chip = (struct sun6i_rtc_dev *) id;
413 	irqreturn_t ret = IRQ_NONE;
414 	u32 val;
415 
416 	spin_lock(&chip->lock);
417 	val = readl(chip->base + SUN6I_ALRM_IRQ_STA);
418 
419 	if (val & SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND) {
420 		val |= SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND;
421 		writel(val, chip->base + SUN6I_ALRM_IRQ_STA);
422 
423 		rtc_update_irq(chip->rtc, 1, RTC_AF | RTC_IRQF);
424 
425 		ret = IRQ_HANDLED;
426 	}
427 	spin_unlock(&chip->lock);
428 
429 	return ret;
430 }
431 
432 static void sun6i_rtc_setaie(int to, struct sun6i_rtc_dev *chip)
433 {
434 	u32 alrm_val = 0;
435 	u32 alrm_irq_val = 0;
436 	u32 alrm_wake_val = 0;
437 	unsigned long flags;
438 
439 	if (to) {
440 		alrm_val = SUN6I_ALRM_EN_CNT_EN;
441 		alrm_irq_val = SUN6I_ALRM_IRQ_EN_CNT_IRQ_EN;
442 		alrm_wake_val = SUN6I_ALARM_CONFIG_WAKEUP;
443 	} else {
444 		writel(SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND,
445 		       chip->base + SUN6I_ALRM_IRQ_STA);
446 	}
447 
448 	spin_lock_irqsave(&chip->lock, flags);
449 	writel(alrm_val, chip->base + SUN6I_ALRM_EN);
450 	writel(alrm_irq_val, chip->base + SUN6I_ALRM_IRQ_EN);
451 	writel(alrm_wake_val, chip->base + SUN6I_ALARM_CONFIG);
452 	spin_unlock_irqrestore(&chip->lock, flags);
453 }
454 
455 static int sun6i_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
456 {
457 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
458 	u32 date, time;
459 
460 	/*
461 	 * read again in case it changes
462 	 */
463 	do {
464 		date = readl(chip->base + SUN6I_RTC_YMD);
465 		time = readl(chip->base + SUN6I_RTC_HMS);
466 	} while ((date != readl(chip->base + SUN6I_RTC_YMD)) ||
467 		 (time != readl(chip->base + SUN6I_RTC_HMS)));
468 
469 	rtc_tm->tm_sec  = SUN6I_TIME_GET_SEC_VALUE(time);
470 	rtc_tm->tm_min  = SUN6I_TIME_GET_MIN_VALUE(time);
471 	rtc_tm->tm_hour = SUN6I_TIME_GET_HOUR_VALUE(time);
472 
473 	rtc_tm->tm_mday = SUN6I_DATE_GET_DAY_VALUE(date);
474 	rtc_tm->tm_mon  = SUN6I_DATE_GET_MON_VALUE(date);
475 	rtc_tm->tm_year = SUN6I_DATE_GET_YEAR_VALUE(date);
476 
477 	rtc_tm->tm_mon  -= 1;
478 
479 	/*
480 	 * switch from (data_year->min)-relative offset to
481 	 * a (1900)-relative one
482 	 */
483 	rtc_tm->tm_year += SUN6I_YEAR_OFF;
484 
485 	return 0;
486 }
487 
488 static int sun6i_rtc_getalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
489 {
490 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
491 	unsigned long flags;
492 	u32 alrm_st;
493 	u32 alrm_en;
494 
495 	spin_lock_irqsave(&chip->lock, flags);
496 	alrm_en = readl(chip->base + SUN6I_ALRM_IRQ_EN);
497 	alrm_st = readl(chip->base + SUN6I_ALRM_IRQ_STA);
498 	spin_unlock_irqrestore(&chip->lock, flags);
499 
500 	wkalrm->enabled = !!(alrm_en & SUN6I_ALRM_EN_CNT_EN);
501 	wkalrm->pending = !!(alrm_st & SUN6I_ALRM_EN_CNT_EN);
502 	rtc_time_to_tm(chip->alarm, &wkalrm->time);
503 
504 	return 0;
505 }
506 
507 static int sun6i_rtc_setalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
508 {
509 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
510 	struct rtc_time *alrm_tm = &wkalrm->time;
511 	struct rtc_time tm_now;
512 	unsigned long time_now = 0;
513 	unsigned long time_set = 0;
514 	unsigned long time_gap = 0;
515 	int ret = 0;
516 
517 	ret = sun6i_rtc_gettime(dev, &tm_now);
518 	if (ret < 0) {
519 		dev_err(dev, "Error in getting time\n");
520 		return -EINVAL;
521 	}
522 
523 	rtc_tm_to_time(alrm_tm, &time_set);
524 	rtc_tm_to_time(&tm_now, &time_now);
525 	if (time_set <= time_now) {
526 		dev_err(dev, "Date to set in the past\n");
527 		return -EINVAL;
528 	}
529 
530 	time_gap = time_set - time_now;
531 
532 	if (time_gap > U32_MAX) {
533 		dev_err(dev, "Date too far in the future\n");
534 		return -EINVAL;
535 	}
536 
537 	sun6i_rtc_setaie(0, chip);
538 	writel(0, chip->base + SUN6I_ALRM_COUNTER);
539 	usleep_range(100, 300);
540 
541 	writel(time_gap, chip->base + SUN6I_ALRM_COUNTER);
542 	chip->alarm = time_set;
543 
544 	sun6i_rtc_setaie(wkalrm->enabled, chip);
545 
546 	return 0;
547 }
548 
549 static int sun6i_rtc_wait(struct sun6i_rtc_dev *chip, int offset,
550 			  unsigned int mask, unsigned int ms_timeout)
551 {
552 	const unsigned long timeout = jiffies + msecs_to_jiffies(ms_timeout);
553 	u32 reg;
554 
555 	do {
556 		reg = readl(chip->base + offset);
557 		reg &= mask;
558 
559 		if (!reg)
560 			return 0;
561 
562 	} while (time_before(jiffies, timeout));
563 
564 	return -ETIMEDOUT;
565 }
566 
567 static int sun6i_rtc_settime(struct device *dev, struct rtc_time *rtc_tm)
568 {
569 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
570 	u32 date = 0;
571 	u32 time = 0;
572 	int year;
573 
574 	year = rtc_tm->tm_year + 1900;
575 	if (year < SUN6I_YEAR_MIN || year > SUN6I_YEAR_MAX) {
576 		dev_err(dev, "rtc only supports year in range %d - %d\n",
577 			SUN6I_YEAR_MIN, SUN6I_YEAR_MAX);
578 		return -EINVAL;
579 	}
580 
581 	rtc_tm->tm_year -= SUN6I_YEAR_OFF;
582 	rtc_tm->tm_mon += 1;
583 
584 	date = SUN6I_DATE_SET_DAY_VALUE(rtc_tm->tm_mday) |
585 		SUN6I_DATE_SET_MON_VALUE(rtc_tm->tm_mon)  |
586 		SUN6I_DATE_SET_YEAR_VALUE(rtc_tm->tm_year);
587 
588 	if (is_leap_year(year))
589 		date |= SUN6I_LEAP_SET_VALUE(1);
590 
591 	time = SUN6I_TIME_SET_SEC_VALUE(rtc_tm->tm_sec)  |
592 		SUN6I_TIME_SET_MIN_VALUE(rtc_tm->tm_min)  |
593 		SUN6I_TIME_SET_HOUR_VALUE(rtc_tm->tm_hour);
594 
595 	/* Check whether registers are writable */
596 	if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
597 			   SUN6I_LOSC_CTRL_ACC_MASK, 50)) {
598 		dev_err(dev, "rtc is still busy.\n");
599 		return -EBUSY;
600 	}
601 
602 	writel(time, chip->base + SUN6I_RTC_HMS);
603 
604 	/*
605 	 * After writing the RTC HH-MM-SS register, the
606 	 * SUN6I_LOSC_CTRL_RTC_HMS_ACC bit is set and it will not
607 	 * be cleared until the real writing operation is finished
608 	 */
609 
610 	if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
611 			   SUN6I_LOSC_CTRL_RTC_HMS_ACC, 50)) {
612 		dev_err(dev, "Failed to set rtc time.\n");
613 		return -ETIMEDOUT;
614 	}
615 
616 	writel(date, chip->base + SUN6I_RTC_YMD);
617 
618 	/*
619 	 * After writing the RTC YY-MM-DD register, the
620 	 * SUN6I_LOSC_CTRL_RTC_YMD_ACC bit is set and it will not
621 	 * be cleared until the real writing operation is finished
622 	 */
623 
624 	if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
625 			   SUN6I_LOSC_CTRL_RTC_YMD_ACC, 50)) {
626 		dev_err(dev, "Failed to set rtc time.\n");
627 		return -ETIMEDOUT;
628 	}
629 
630 	return 0;
631 }
632 
633 static int sun6i_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
634 {
635 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
636 
637 	if (!enabled)
638 		sun6i_rtc_setaie(enabled, chip);
639 
640 	return 0;
641 }
642 
643 static const struct rtc_class_ops sun6i_rtc_ops = {
644 	.read_time		= sun6i_rtc_gettime,
645 	.set_time		= sun6i_rtc_settime,
646 	.read_alarm		= sun6i_rtc_getalarm,
647 	.set_alarm		= sun6i_rtc_setalarm,
648 	.alarm_irq_enable	= sun6i_rtc_alarm_irq_enable
649 };
650 
651 #ifdef CONFIG_PM_SLEEP
652 /* Enable IRQ wake on suspend, to wake up from RTC. */
653 static int sun6i_rtc_suspend(struct device *dev)
654 {
655 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
656 
657 	if (device_may_wakeup(dev))
658 		enable_irq_wake(chip->irq);
659 
660 	return 0;
661 }
662 
663 /* Disable IRQ wake on resume. */
664 static int sun6i_rtc_resume(struct device *dev)
665 {
666 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
667 
668 	if (device_may_wakeup(dev))
669 		disable_irq_wake(chip->irq);
670 
671 	return 0;
672 }
673 #endif
674 
675 static SIMPLE_DEV_PM_OPS(sun6i_rtc_pm_ops,
676 	sun6i_rtc_suspend, sun6i_rtc_resume);
677 
678 static int sun6i_rtc_probe(struct platform_device *pdev)
679 {
680 	struct sun6i_rtc_dev *chip = sun6i_rtc;
681 	int ret;
682 
683 	if (!chip)
684 		return -ENODEV;
685 
686 	platform_set_drvdata(pdev, chip);
687 
688 	chip->irq = platform_get_irq(pdev, 0);
689 	if (chip->irq < 0)
690 		return chip->irq;
691 
692 	ret = devm_request_irq(&pdev->dev, chip->irq, sun6i_rtc_alarmirq,
693 			       0, dev_name(&pdev->dev), chip);
694 	if (ret) {
695 		dev_err(&pdev->dev, "Could not request IRQ\n");
696 		return ret;
697 	}
698 
699 	/* clear the alarm counter value */
700 	writel(0, chip->base + SUN6I_ALRM_COUNTER);
701 
702 	/* disable counter alarm */
703 	writel(0, chip->base + SUN6I_ALRM_EN);
704 
705 	/* disable counter alarm interrupt */
706 	writel(0, chip->base + SUN6I_ALRM_IRQ_EN);
707 
708 	/* disable week alarm */
709 	writel(0, chip->base + SUN6I_ALRM1_EN);
710 
711 	/* disable week alarm interrupt */
712 	writel(0, chip->base + SUN6I_ALRM1_IRQ_EN);
713 
714 	/* clear counter alarm pending interrupts */
715 	writel(SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND,
716 	       chip->base + SUN6I_ALRM_IRQ_STA);
717 
718 	/* clear week alarm pending interrupts */
719 	writel(SUN6I_ALRM1_IRQ_STA_WEEK_IRQ_PEND,
720 	       chip->base + SUN6I_ALRM1_IRQ_STA);
721 
722 	/* disable alarm wakeup */
723 	writel(0, chip->base + SUN6I_ALARM_CONFIG);
724 
725 	clk_prepare_enable(chip->losc);
726 
727 	device_init_wakeup(&pdev->dev, 1);
728 
729 	chip->rtc = devm_rtc_device_register(&pdev->dev, "rtc-sun6i",
730 					     &sun6i_rtc_ops, THIS_MODULE);
731 	if (IS_ERR(chip->rtc)) {
732 		dev_err(&pdev->dev, "unable to register device\n");
733 		return PTR_ERR(chip->rtc);
734 	}
735 
736 	dev_info(&pdev->dev, "RTC enabled\n");
737 
738 	return 0;
739 }
740 
741 /*
742  * As far as RTC functionality goes, all models are the same. The
743  * datasheets claim that different models have different number of
744  * registers available for non-volatile storage, but experiments show
745  * that all SoCs have 16 registers available for this purpose.
746  */
747 static const struct of_device_id sun6i_rtc_dt_ids[] = {
748 	{ .compatible = "allwinner,sun6i-a31-rtc" },
749 	{ .compatible = "allwinner,sun8i-a23-rtc" },
750 	{ .compatible = "allwinner,sun8i-h3-rtc" },
751 	{ .compatible = "allwinner,sun8i-r40-rtc" },
752 	{ .compatible = "allwinner,sun8i-v3-rtc" },
753 	{ .compatible = "allwinner,sun50i-h5-rtc" },
754 	{ .compatible = "allwinner,sun50i-h6-rtc" },
755 	{ /* sentinel */ },
756 };
757 MODULE_DEVICE_TABLE(of, sun6i_rtc_dt_ids);
758 
759 static struct platform_driver sun6i_rtc_driver = {
760 	.probe		= sun6i_rtc_probe,
761 	.driver		= {
762 		.name		= "sun6i-rtc",
763 		.of_match_table = sun6i_rtc_dt_ids,
764 		.pm = &sun6i_rtc_pm_ops,
765 	},
766 };
767 builtin_platform_driver(sun6i_rtc_driver);
768