xref: /openbmc/linux/drivers/rtc/rtc-sun6i.c (revision 8bdc2a19)
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/clk/sunxi-ng.h>
17 #include <linux/delay.h>
18 #include <linux/err.h>
19 #include <linux/fs.h>
20 #include <linux/init.h>
21 #include <linux/interrupt.h>
22 #include <linux/io.h>
23 #include <linux/kernel.h>
24 #include <linux/module.h>
25 #include <linux/of.h>
26 #include <linux/of_address.h>
27 #include <linux/of_device.h>
28 #include <linux/platform_device.h>
29 #include <linux/rtc.h>
30 #include <linux/slab.h>
31 #include <linux/types.h>
32 
33 /* Control register */
34 #define SUN6I_LOSC_CTRL				0x0000
35 #define SUN6I_LOSC_CTRL_KEY			(0x16aa << 16)
36 #define SUN6I_LOSC_CTRL_AUTO_SWT_BYPASS		BIT(15)
37 #define SUN6I_LOSC_CTRL_ALM_DHMS_ACC		BIT(9)
38 #define SUN6I_LOSC_CTRL_RTC_HMS_ACC		BIT(8)
39 #define SUN6I_LOSC_CTRL_RTC_YMD_ACC		BIT(7)
40 #define SUN6I_LOSC_CTRL_EXT_LOSC_EN		BIT(4)
41 #define SUN6I_LOSC_CTRL_EXT_OSC			BIT(0)
42 #define SUN6I_LOSC_CTRL_ACC_MASK		GENMASK(9, 7)
43 
44 #define SUN6I_LOSC_CLK_PRESCAL			0x0008
45 
46 /* RTC */
47 #define SUN6I_RTC_YMD				0x0010
48 #define SUN6I_RTC_HMS				0x0014
49 
50 /* Alarm 0 (counter) */
51 #define SUN6I_ALRM_COUNTER			0x0020
52 /* This holds the remaining alarm seconds on older SoCs (current value) */
53 #define SUN6I_ALRM_COUNTER_HMS			0x0024
54 #define SUN6I_ALRM_EN				0x0028
55 #define SUN6I_ALRM_EN_CNT_EN			BIT(0)
56 #define SUN6I_ALRM_IRQ_EN			0x002c
57 #define SUN6I_ALRM_IRQ_EN_CNT_IRQ_EN		BIT(0)
58 #define SUN6I_ALRM_IRQ_STA			0x0030
59 #define SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND		BIT(0)
60 
61 /* Alarm 1 (wall clock) */
62 #define SUN6I_ALRM1_EN				0x0044
63 #define SUN6I_ALRM1_IRQ_EN			0x0048
64 #define SUN6I_ALRM1_IRQ_STA			0x004c
65 #define SUN6I_ALRM1_IRQ_STA_WEEK_IRQ_PEND	BIT(0)
66 
67 /* Alarm config */
68 #define SUN6I_ALARM_CONFIG			0x0050
69 #define SUN6I_ALARM_CONFIG_WAKEUP		BIT(0)
70 
71 #define SUN6I_LOSC_OUT_GATING			0x0060
72 #define SUN6I_LOSC_OUT_GATING_EN_OFFSET		0
73 
74 /*
75  * Get date values
76  */
77 #define SUN6I_DATE_GET_DAY_VALUE(x)		((x)  & 0x0000001f)
78 #define SUN6I_DATE_GET_MON_VALUE(x)		(((x) & 0x00000f00) >> 8)
79 #define SUN6I_DATE_GET_YEAR_VALUE(x)		(((x) & 0x003f0000) >> 16)
80 #define SUN6I_LEAP_GET_VALUE(x)			(((x) & 0x00400000) >> 22)
81 
82 /*
83  * Get time values
84  */
85 #define SUN6I_TIME_GET_SEC_VALUE(x)		((x)  & 0x0000003f)
86 #define SUN6I_TIME_GET_MIN_VALUE(x)		(((x) & 0x00003f00) >> 8)
87 #define SUN6I_TIME_GET_HOUR_VALUE(x)		(((x) & 0x001f0000) >> 16)
88 
89 /*
90  * Set date values
91  */
92 #define SUN6I_DATE_SET_DAY_VALUE(x)		((x)       & 0x0000001f)
93 #define SUN6I_DATE_SET_MON_VALUE(x)		((x) <<  8 & 0x00000f00)
94 #define SUN6I_DATE_SET_YEAR_VALUE(x)		((x) << 16 & 0x003f0000)
95 #define SUN6I_LEAP_SET_VALUE(x)			((x) << 22 & 0x00400000)
96 
97 /*
98  * Set time values
99  */
100 #define SUN6I_TIME_SET_SEC_VALUE(x)		((x)       & 0x0000003f)
101 #define SUN6I_TIME_SET_MIN_VALUE(x)		((x) <<  8 & 0x00003f00)
102 #define SUN6I_TIME_SET_HOUR_VALUE(x)		((x) << 16 & 0x001f0000)
103 
104 /*
105  * The year parameter passed to the driver is usually an offset relative to
106  * the year 1900. This macro is used to convert this offset to another one
107  * relative to the minimum year allowed by the hardware.
108  *
109  * The year range is 1970 - 2033. This range is selected to match Allwinner's
110  * driver, even though it is somewhat limited.
111  */
112 #define SUN6I_YEAR_MIN				1970
113 #define SUN6I_YEAR_OFF				(SUN6I_YEAR_MIN - 1900)
114 
115 #define SECS_PER_DAY				(24 * 3600ULL)
116 
117 /*
118  * There are other differences between models, including:
119  *
120  *   - number of GPIO pins that can be configured to hold a certain level
121  *   - crypto-key related registers (H5, H6)
122  *   - boot process related (super standby, secondary processor entry address)
123  *     registers (R40, H6)
124  *   - SYS power domain controls (R40)
125  *   - DCXO controls (H6)
126  *   - RC oscillator calibration (H6)
127  *
128  * These functions are not covered by this driver.
129  */
130 struct sun6i_rtc_clk_data {
131 	unsigned long rc_osc_rate;
132 	unsigned int fixed_prescaler : 16;
133 	unsigned int has_prescaler : 1;
134 	unsigned int has_out_clk : 1;
135 	unsigned int export_iosc : 1;
136 	unsigned int has_losc_en : 1;
137 	unsigned int has_auto_swt : 1;
138 };
139 
140 #define RTC_LINEAR_DAY	BIT(0)
141 
142 struct sun6i_rtc_dev {
143 	struct rtc_device *rtc;
144 	const struct sun6i_rtc_clk_data *data;
145 	void __iomem *base;
146 	int irq;
147 	time64_t alarm;
148 	unsigned long flags;
149 
150 	struct clk_hw hw;
151 	struct clk_hw *int_osc;
152 	struct clk *losc;
153 	struct clk *ext_losc;
154 
155 	spinlock_t lock;
156 };
157 
158 static struct sun6i_rtc_dev *sun6i_rtc;
159 
160 static unsigned long sun6i_rtc_osc_recalc_rate(struct clk_hw *hw,
161 					       unsigned long parent_rate)
162 {
163 	struct sun6i_rtc_dev *rtc = container_of(hw, struct sun6i_rtc_dev, hw);
164 	u32 val = 0;
165 
166 	val = readl(rtc->base + SUN6I_LOSC_CTRL);
167 	if (val & SUN6I_LOSC_CTRL_EXT_OSC)
168 		return parent_rate;
169 
170 	if (rtc->data->fixed_prescaler)
171 		parent_rate /= rtc->data->fixed_prescaler;
172 
173 	if (rtc->data->has_prescaler) {
174 		val = readl(rtc->base + SUN6I_LOSC_CLK_PRESCAL);
175 		val &= GENMASK(4, 0);
176 	}
177 
178 	return parent_rate / (val + 1);
179 }
180 
181 static u8 sun6i_rtc_osc_get_parent(struct clk_hw *hw)
182 {
183 	struct sun6i_rtc_dev *rtc = container_of(hw, struct sun6i_rtc_dev, hw);
184 
185 	return readl(rtc->base + SUN6I_LOSC_CTRL) & SUN6I_LOSC_CTRL_EXT_OSC;
186 }
187 
188 static int sun6i_rtc_osc_set_parent(struct clk_hw *hw, u8 index)
189 {
190 	struct sun6i_rtc_dev *rtc = container_of(hw, struct sun6i_rtc_dev, hw);
191 	unsigned long flags;
192 	u32 val;
193 
194 	if (index > 1)
195 		return -EINVAL;
196 
197 	spin_lock_irqsave(&rtc->lock, flags);
198 	val = readl(rtc->base + SUN6I_LOSC_CTRL);
199 	val &= ~SUN6I_LOSC_CTRL_EXT_OSC;
200 	val |= SUN6I_LOSC_CTRL_KEY;
201 	val |= index ? SUN6I_LOSC_CTRL_EXT_OSC : 0;
202 	if (rtc->data->has_losc_en) {
203 		val &= ~SUN6I_LOSC_CTRL_EXT_LOSC_EN;
204 		val |= index ? SUN6I_LOSC_CTRL_EXT_LOSC_EN : 0;
205 	}
206 	writel(val, rtc->base + SUN6I_LOSC_CTRL);
207 	spin_unlock_irqrestore(&rtc->lock, flags);
208 
209 	return 0;
210 }
211 
212 static const struct clk_ops sun6i_rtc_osc_ops = {
213 	.recalc_rate	= sun6i_rtc_osc_recalc_rate,
214 
215 	.get_parent	= sun6i_rtc_osc_get_parent,
216 	.set_parent	= sun6i_rtc_osc_set_parent,
217 };
218 
219 static void __init sun6i_rtc_clk_init(struct device_node *node,
220 				      const struct sun6i_rtc_clk_data *data)
221 {
222 	struct clk_hw_onecell_data *clk_data;
223 	struct sun6i_rtc_dev *rtc;
224 	struct clk_init_data init = {
225 		.ops		= &sun6i_rtc_osc_ops,
226 		.name		= "losc",
227 	};
228 	const char *iosc_name = "rtc-int-osc";
229 	const char *clkout_name = "osc32k-out";
230 	const char *parents[2];
231 	u32 reg;
232 
233 	rtc = kzalloc(sizeof(*rtc), GFP_KERNEL);
234 	if (!rtc)
235 		return;
236 
237 	rtc->data = data;
238 	clk_data = kzalloc(struct_size(clk_data, hws, 3), GFP_KERNEL);
239 	if (!clk_data) {
240 		kfree(rtc);
241 		return;
242 	}
243 
244 	spin_lock_init(&rtc->lock);
245 
246 	rtc->base = of_io_request_and_map(node, 0, of_node_full_name(node));
247 	if (IS_ERR(rtc->base)) {
248 		pr_crit("Can't map RTC registers");
249 		goto err;
250 	}
251 
252 	reg = SUN6I_LOSC_CTRL_KEY;
253 	if (rtc->data->has_auto_swt) {
254 		/* Bypass auto-switch to int osc, on ext losc failure */
255 		reg |= SUN6I_LOSC_CTRL_AUTO_SWT_BYPASS;
256 		writel(reg, rtc->base + SUN6I_LOSC_CTRL);
257 	}
258 
259 	/* Switch to the external, more precise, oscillator, if present */
260 	if (of_get_property(node, "clocks", NULL)) {
261 		reg |= SUN6I_LOSC_CTRL_EXT_OSC;
262 		if (rtc->data->has_losc_en)
263 			reg |= SUN6I_LOSC_CTRL_EXT_LOSC_EN;
264 	}
265 	writel(reg, rtc->base + SUN6I_LOSC_CTRL);
266 
267 	/* Yes, I know, this is ugly. */
268 	sun6i_rtc = rtc;
269 
270 	/* Only read IOSC name from device tree if it is exported */
271 	if (rtc->data->export_iosc)
272 		of_property_read_string_index(node, "clock-output-names", 2,
273 					      &iosc_name);
274 
275 	rtc->int_osc = clk_hw_register_fixed_rate_with_accuracy(NULL,
276 								iosc_name,
277 								NULL, 0,
278 								rtc->data->rc_osc_rate,
279 								300000000);
280 	if (IS_ERR(rtc->int_osc)) {
281 		pr_crit("Couldn't register the internal oscillator\n");
282 		goto err;
283 	}
284 
285 	parents[0] = clk_hw_get_name(rtc->int_osc);
286 	/* If there is no external oscillator, this will be NULL and ... */
287 	parents[1] = of_clk_get_parent_name(node, 0);
288 
289 	rtc->hw.init = &init;
290 
291 	init.parent_names = parents;
292 	/* ... number of clock parents will be 1. */
293 	init.num_parents = of_clk_get_parent_count(node) + 1;
294 	of_property_read_string_index(node, "clock-output-names", 0,
295 				      &init.name);
296 
297 	rtc->losc = clk_register(NULL, &rtc->hw);
298 	if (IS_ERR(rtc->losc)) {
299 		pr_crit("Couldn't register the LOSC clock\n");
300 		goto err_register;
301 	}
302 
303 	of_property_read_string_index(node, "clock-output-names", 1,
304 				      &clkout_name);
305 	rtc->ext_losc = clk_register_gate(NULL, clkout_name, init.name,
306 					  0, rtc->base + SUN6I_LOSC_OUT_GATING,
307 					  SUN6I_LOSC_OUT_GATING_EN_OFFSET, 0,
308 					  &rtc->lock);
309 	if (IS_ERR(rtc->ext_losc)) {
310 		pr_crit("Couldn't register the LOSC external gate\n");
311 		goto err_register;
312 	}
313 
314 	clk_data->num = 2;
315 	clk_data->hws[0] = &rtc->hw;
316 	clk_data->hws[1] = __clk_get_hw(rtc->ext_losc);
317 	if (rtc->data->export_iosc) {
318 		clk_data->hws[2] = rtc->int_osc;
319 		clk_data->num = 3;
320 	}
321 	of_clk_add_hw_provider(node, of_clk_hw_onecell_get, clk_data);
322 	return;
323 
324 err_register:
325 	clk_hw_unregister_fixed_rate(rtc->int_osc);
326 err:
327 	kfree(clk_data);
328 }
329 
330 static const struct sun6i_rtc_clk_data sun6i_a31_rtc_data = {
331 	.rc_osc_rate = 667000, /* datasheet says 600 ~ 700 KHz */
332 	.has_prescaler = 1,
333 };
334 
335 static void __init sun6i_a31_rtc_clk_init(struct device_node *node)
336 {
337 	sun6i_rtc_clk_init(node, &sun6i_a31_rtc_data);
338 }
339 CLK_OF_DECLARE_DRIVER(sun6i_a31_rtc_clk, "allwinner,sun6i-a31-rtc",
340 		      sun6i_a31_rtc_clk_init);
341 
342 static const struct sun6i_rtc_clk_data sun8i_a23_rtc_data = {
343 	.rc_osc_rate = 667000, /* datasheet says 600 ~ 700 KHz */
344 	.has_prescaler = 1,
345 	.has_out_clk = 1,
346 };
347 
348 static void __init sun8i_a23_rtc_clk_init(struct device_node *node)
349 {
350 	sun6i_rtc_clk_init(node, &sun8i_a23_rtc_data);
351 }
352 CLK_OF_DECLARE_DRIVER(sun8i_a23_rtc_clk, "allwinner,sun8i-a23-rtc",
353 		      sun8i_a23_rtc_clk_init);
354 
355 static const struct sun6i_rtc_clk_data sun8i_h3_rtc_data = {
356 	.rc_osc_rate = 16000000,
357 	.fixed_prescaler = 32,
358 	.has_prescaler = 1,
359 	.has_out_clk = 1,
360 	.export_iosc = 1,
361 };
362 
363 static void __init sun8i_h3_rtc_clk_init(struct device_node *node)
364 {
365 	sun6i_rtc_clk_init(node, &sun8i_h3_rtc_data);
366 }
367 CLK_OF_DECLARE_DRIVER(sun8i_h3_rtc_clk, "allwinner,sun8i-h3-rtc",
368 		      sun8i_h3_rtc_clk_init);
369 /* As far as we are concerned, clocks for H5 are the same as H3 */
370 CLK_OF_DECLARE_DRIVER(sun50i_h5_rtc_clk, "allwinner,sun50i-h5-rtc",
371 		      sun8i_h3_rtc_clk_init);
372 
373 static const struct sun6i_rtc_clk_data sun50i_h6_rtc_data = {
374 	.rc_osc_rate = 16000000,
375 	.fixed_prescaler = 32,
376 	.has_prescaler = 1,
377 	.has_out_clk = 1,
378 	.export_iosc = 1,
379 	.has_losc_en = 1,
380 	.has_auto_swt = 1,
381 };
382 
383 static void __init sun50i_h6_rtc_clk_init(struct device_node *node)
384 {
385 	sun6i_rtc_clk_init(node, &sun50i_h6_rtc_data);
386 }
387 CLK_OF_DECLARE_DRIVER(sun50i_h6_rtc_clk, "allwinner,sun50i-h6-rtc",
388 		      sun50i_h6_rtc_clk_init);
389 
390 /*
391  * The R40 user manual is self-conflicting on whether the prescaler is
392  * fixed or configurable. The clock diagram shows it as fixed, but there
393  * is also a configurable divider in the RTC block.
394  */
395 static const struct sun6i_rtc_clk_data sun8i_r40_rtc_data = {
396 	.rc_osc_rate = 16000000,
397 	.fixed_prescaler = 512,
398 };
399 static void __init sun8i_r40_rtc_clk_init(struct device_node *node)
400 {
401 	sun6i_rtc_clk_init(node, &sun8i_r40_rtc_data);
402 }
403 CLK_OF_DECLARE_DRIVER(sun8i_r40_rtc_clk, "allwinner,sun8i-r40-rtc",
404 		      sun8i_r40_rtc_clk_init);
405 
406 static const struct sun6i_rtc_clk_data sun8i_v3_rtc_data = {
407 	.rc_osc_rate = 32000,
408 	.has_out_clk = 1,
409 };
410 
411 static void __init sun8i_v3_rtc_clk_init(struct device_node *node)
412 {
413 	sun6i_rtc_clk_init(node, &sun8i_v3_rtc_data);
414 }
415 CLK_OF_DECLARE_DRIVER(sun8i_v3_rtc_clk, "allwinner,sun8i-v3-rtc",
416 		      sun8i_v3_rtc_clk_init);
417 
418 static irqreturn_t sun6i_rtc_alarmirq(int irq, void *id)
419 {
420 	struct sun6i_rtc_dev *chip = (struct sun6i_rtc_dev *) id;
421 	irqreturn_t ret = IRQ_NONE;
422 	u32 val;
423 
424 	spin_lock(&chip->lock);
425 	val = readl(chip->base + SUN6I_ALRM_IRQ_STA);
426 
427 	if (val & SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND) {
428 		val |= SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND;
429 		writel(val, chip->base + SUN6I_ALRM_IRQ_STA);
430 
431 		rtc_update_irq(chip->rtc, 1, RTC_AF | RTC_IRQF);
432 
433 		ret = IRQ_HANDLED;
434 	}
435 	spin_unlock(&chip->lock);
436 
437 	return ret;
438 }
439 
440 static void sun6i_rtc_setaie(int to, struct sun6i_rtc_dev *chip)
441 {
442 	u32 alrm_val = 0;
443 	u32 alrm_irq_val = 0;
444 	u32 alrm_wake_val = 0;
445 	unsigned long flags;
446 
447 	if (to) {
448 		alrm_val = SUN6I_ALRM_EN_CNT_EN;
449 		alrm_irq_val = SUN6I_ALRM_IRQ_EN_CNT_IRQ_EN;
450 		alrm_wake_val = SUN6I_ALARM_CONFIG_WAKEUP;
451 	} else {
452 		writel(SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND,
453 		       chip->base + SUN6I_ALRM_IRQ_STA);
454 	}
455 
456 	spin_lock_irqsave(&chip->lock, flags);
457 	writel(alrm_val, chip->base + SUN6I_ALRM_EN);
458 	writel(alrm_irq_val, chip->base + SUN6I_ALRM_IRQ_EN);
459 	writel(alrm_wake_val, chip->base + SUN6I_ALARM_CONFIG);
460 	spin_unlock_irqrestore(&chip->lock, flags);
461 }
462 
463 static int sun6i_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
464 {
465 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
466 	u32 date, time;
467 
468 	/*
469 	 * read again in case it changes
470 	 */
471 	do {
472 		date = readl(chip->base + SUN6I_RTC_YMD);
473 		time = readl(chip->base + SUN6I_RTC_HMS);
474 	} while ((date != readl(chip->base + SUN6I_RTC_YMD)) ||
475 		 (time != readl(chip->base + SUN6I_RTC_HMS)));
476 
477 	if (chip->flags & RTC_LINEAR_DAY) {
478 		/*
479 		 * Newer chips store a linear day number, the manual
480 		 * does not mandate any epoch base. The BSP driver uses
481 		 * the UNIX epoch, let's just copy that, as it's the
482 		 * easiest anyway.
483 		 */
484 		rtc_time64_to_tm((date & 0xffff) * SECS_PER_DAY, rtc_tm);
485 	} else {
486 		rtc_tm->tm_mday = SUN6I_DATE_GET_DAY_VALUE(date);
487 		rtc_tm->tm_mon  = SUN6I_DATE_GET_MON_VALUE(date) - 1;
488 		rtc_tm->tm_year = SUN6I_DATE_GET_YEAR_VALUE(date);
489 
490 		/*
491 		 * switch from (data_year->min)-relative offset to
492 		 * a (1900)-relative one
493 		 */
494 		rtc_tm->tm_year += SUN6I_YEAR_OFF;
495 	}
496 
497 	rtc_tm->tm_sec  = SUN6I_TIME_GET_SEC_VALUE(time);
498 	rtc_tm->tm_min  = SUN6I_TIME_GET_MIN_VALUE(time);
499 	rtc_tm->tm_hour = SUN6I_TIME_GET_HOUR_VALUE(time);
500 
501 	return 0;
502 }
503 
504 static int sun6i_rtc_getalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
505 {
506 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
507 	unsigned long flags;
508 	u32 alrm_st;
509 	u32 alrm_en;
510 
511 	spin_lock_irqsave(&chip->lock, flags);
512 	alrm_en = readl(chip->base + SUN6I_ALRM_IRQ_EN);
513 	alrm_st = readl(chip->base + SUN6I_ALRM_IRQ_STA);
514 	spin_unlock_irqrestore(&chip->lock, flags);
515 
516 	wkalrm->enabled = !!(alrm_en & SUN6I_ALRM_EN_CNT_EN);
517 	wkalrm->pending = !!(alrm_st & SUN6I_ALRM_EN_CNT_EN);
518 	rtc_time64_to_tm(chip->alarm, &wkalrm->time);
519 
520 	return 0;
521 }
522 
523 static int sun6i_rtc_setalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
524 {
525 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
526 	struct rtc_time *alrm_tm = &wkalrm->time;
527 	struct rtc_time tm_now;
528 	time64_t time_set;
529 	u32 counter_val, counter_val_hms;
530 	int ret;
531 
532 	time_set = rtc_tm_to_time64(alrm_tm);
533 
534 	if (chip->flags & RTC_LINEAR_DAY) {
535 		/*
536 		 * The alarm registers hold the actual alarm time, encoded
537 		 * in the same way (linear day + HMS) as the current time.
538 		 */
539 		counter_val_hms = SUN6I_TIME_SET_SEC_VALUE(alrm_tm->tm_sec)  |
540 				  SUN6I_TIME_SET_MIN_VALUE(alrm_tm->tm_min)  |
541 				  SUN6I_TIME_SET_HOUR_VALUE(alrm_tm->tm_hour);
542 		/* The division will cut off the H:M:S part of alrm_tm. */
543 		counter_val = div_u64(rtc_tm_to_time64(alrm_tm), SECS_PER_DAY);
544 	} else {
545 		/* The alarm register holds the number of seconds left. */
546 		time64_t time_now;
547 
548 		ret = sun6i_rtc_gettime(dev, &tm_now);
549 		if (ret < 0) {
550 			dev_err(dev, "Error in getting time\n");
551 			return -EINVAL;
552 		}
553 
554 		time_now = rtc_tm_to_time64(&tm_now);
555 		if (time_set <= time_now) {
556 			dev_err(dev, "Date to set in the past\n");
557 			return -EINVAL;
558 		}
559 		if ((time_set - time_now) > U32_MAX) {
560 			dev_err(dev, "Date too far in the future\n");
561 			return -EINVAL;
562 		}
563 
564 		counter_val = time_set - time_now;
565 	}
566 
567 	sun6i_rtc_setaie(0, chip);
568 	writel(0, chip->base + SUN6I_ALRM_COUNTER);
569 	if (chip->flags & RTC_LINEAR_DAY)
570 		writel(0, chip->base + SUN6I_ALRM_COUNTER_HMS);
571 	usleep_range(100, 300);
572 
573 	writel(counter_val, chip->base + SUN6I_ALRM_COUNTER);
574 	if (chip->flags & RTC_LINEAR_DAY)
575 		writel(counter_val_hms, chip->base + SUN6I_ALRM_COUNTER_HMS);
576 	chip->alarm = time_set;
577 
578 	sun6i_rtc_setaie(wkalrm->enabled, chip);
579 
580 	return 0;
581 }
582 
583 static int sun6i_rtc_wait(struct sun6i_rtc_dev *chip, int offset,
584 			  unsigned int mask, unsigned int ms_timeout)
585 {
586 	const unsigned long timeout = jiffies + msecs_to_jiffies(ms_timeout);
587 	u32 reg;
588 
589 	do {
590 		reg = readl(chip->base + offset);
591 		reg &= mask;
592 
593 		if (!reg)
594 			return 0;
595 
596 	} while (time_before(jiffies, timeout));
597 
598 	return -ETIMEDOUT;
599 }
600 
601 static int sun6i_rtc_settime(struct device *dev, struct rtc_time *rtc_tm)
602 {
603 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
604 	u32 date = 0;
605 	u32 time = 0;
606 
607 	time = SUN6I_TIME_SET_SEC_VALUE(rtc_tm->tm_sec)  |
608 		SUN6I_TIME_SET_MIN_VALUE(rtc_tm->tm_min)  |
609 		SUN6I_TIME_SET_HOUR_VALUE(rtc_tm->tm_hour);
610 
611 	if (chip->flags & RTC_LINEAR_DAY) {
612 		/* The division will cut off the H:M:S part of rtc_tm. */
613 		date = div_u64(rtc_tm_to_time64(rtc_tm), SECS_PER_DAY);
614 	} else {
615 		rtc_tm->tm_year -= SUN6I_YEAR_OFF;
616 		rtc_tm->tm_mon += 1;
617 
618 		date = SUN6I_DATE_SET_DAY_VALUE(rtc_tm->tm_mday) |
619 			SUN6I_DATE_SET_MON_VALUE(rtc_tm->tm_mon)  |
620 			SUN6I_DATE_SET_YEAR_VALUE(rtc_tm->tm_year);
621 
622 		if (is_leap_year(rtc_tm->tm_year + SUN6I_YEAR_MIN))
623 			date |= SUN6I_LEAP_SET_VALUE(1);
624 	}
625 
626 	/* Check whether registers are writable */
627 	if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
628 			   SUN6I_LOSC_CTRL_ACC_MASK, 50)) {
629 		dev_err(dev, "rtc is still busy.\n");
630 		return -EBUSY;
631 	}
632 
633 	writel(time, chip->base + SUN6I_RTC_HMS);
634 
635 	/*
636 	 * After writing the RTC HH-MM-SS register, the
637 	 * SUN6I_LOSC_CTRL_RTC_HMS_ACC bit is set and it will not
638 	 * be cleared until the real writing operation is finished
639 	 */
640 
641 	if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
642 			   SUN6I_LOSC_CTRL_RTC_HMS_ACC, 50)) {
643 		dev_err(dev, "Failed to set rtc time.\n");
644 		return -ETIMEDOUT;
645 	}
646 
647 	writel(date, chip->base + SUN6I_RTC_YMD);
648 
649 	/*
650 	 * After writing the RTC YY-MM-DD register, the
651 	 * SUN6I_LOSC_CTRL_RTC_YMD_ACC bit is set and it will not
652 	 * be cleared until the real writing operation is finished
653 	 */
654 
655 	if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
656 			   SUN6I_LOSC_CTRL_RTC_YMD_ACC, 50)) {
657 		dev_err(dev, "Failed to set rtc time.\n");
658 		return -ETIMEDOUT;
659 	}
660 
661 	return 0;
662 }
663 
664 static int sun6i_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
665 {
666 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
667 
668 	if (!enabled)
669 		sun6i_rtc_setaie(enabled, chip);
670 
671 	return 0;
672 }
673 
674 static const struct rtc_class_ops sun6i_rtc_ops = {
675 	.read_time		= sun6i_rtc_gettime,
676 	.set_time		= sun6i_rtc_settime,
677 	.read_alarm		= sun6i_rtc_getalarm,
678 	.set_alarm		= sun6i_rtc_setalarm,
679 	.alarm_irq_enable	= sun6i_rtc_alarm_irq_enable
680 };
681 
682 #ifdef CONFIG_PM_SLEEP
683 /* Enable IRQ wake on suspend, to wake up from RTC. */
684 static int sun6i_rtc_suspend(struct device *dev)
685 {
686 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
687 
688 	if (device_may_wakeup(dev))
689 		enable_irq_wake(chip->irq);
690 
691 	return 0;
692 }
693 
694 /* Disable IRQ wake on resume. */
695 static int sun6i_rtc_resume(struct device *dev)
696 {
697 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
698 
699 	if (device_may_wakeup(dev))
700 		disable_irq_wake(chip->irq);
701 
702 	return 0;
703 }
704 #endif
705 
706 static SIMPLE_DEV_PM_OPS(sun6i_rtc_pm_ops,
707 	sun6i_rtc_suspend, sun6i_rtc_resume);
708 
709 static void sun6i_rtc_bus_clk_cleanup(void *data)
710 {
711 	struct clk *bus_clk = data;
712 
713 	clk_disable_unprepare(bus_clk);
714 }
715 
716 static int sun6i_rtc_probe(struct platform_device *pdev)
717 {
718 	struct sun6i_rtc_dev *chip = sun6i_rtc;
719 	struct device *dev = &pdev->dev;
720 	struct clk *bus_clk;
721 	int ret;
722 
723 	bus_clk = devm_clk_get_optional(dev, "bus");
724 	if (IS_ERR(bus_clk))
725 		return PTR_ERR(bus_clk);
726 
727 	if (bus_clk) {
728 		ret = clk_prepare_enable(bus_clk);
729 		if (ret)
730 			return ret;
731 
732 		ret = devm_add_action_or_reset(dev, sun6i_rtc_bus_clk_cleanup,
733 					       bus_clk);
734 		if (ret)
735 			return ret;
736 	}
737 
738 	if (!chip) {
739 		chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
740 		if (!chip)
741 			return -ENOMEM;
742 
743 		spin_lock_init(&chip->lock);
744 
745 		chip->base = devm_platform_ioremap_resource(pdev, 0);
746 		if (IS_ERR(chip->base))
747 			return PTR_ERR(chip->base);
748 
749 		if (IS_REACHABLE(CONFIG_SUN6I_RTC_CCU)) {
750 			ret = sun6i_rtc_ccu_probe(dev, chip->base);
751 			if (ret)
752 				return ret;
753 		}
754 	}
755 
756 	platform_set_drvdata(pdev, chip);
757 
758 	chip->flags = (unsigned long)of_device_get_match_data(&pdev->dev);
759 
760 	chip->irq = platform_get_irq(pdev, 0);
761 	if (chip->irq < 0)
762 		return chip->irq;
763 
764 	ret = devm_request_irq(&pdev->dev, chip->irq, sun6i_rtc_alarmirq,
765 			       0, dev_name(&pdev->dev), chip);
766 	if (ret) {
767 		dev_err(&pdev->dev, "Could not request IRQ\n");
768 		return ret;
769 	}
770 
771 	/* clear the alarm counter value */
772 	writel(0, chip->base + SUN6I_ALRM_COUNTER);
773 
774 	/* disable counter alarm */
775 	writel(0, chip->base + SUN6I_ALRM_EN);
776 
777 	/* disable counter alarm interrupt */
778 	writel(0, chip->base + SUN6I_ALRM_IRQ_EN);
779 
780 	/* disable week alarm */
781 	writel(0, chip->base + SUN6I_ALRM1_EN);
782 
783 	/* disable week alarm interrupt */
784 	writel(0, chip->base + SUN6I_ALRM1_IRQ_EN);
785 
786 	/* clear counter alarm pending interrupts */
787 	writel(SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND,
788 	       chip->base + SUN6I_ALRM_IRQ_STA);
789 
790 	/* clear week alarm pending interrupts */
791 	writel(SUN6I_ALRM1_IRQ_STA_WEEK_IRQ_PEND,
792 	       chip->base + SUN6I_ALRM1_IRQ_STA);
793 
794 	/* disable alarm wakeup */
795 	writel(0, chip->base + SUN6I_ALARM_CONFIG);
796 
797 	clk_prepare_enable(chip->losc);
798 
799 	device_init_wakeup(&pdev->dev, 1);
800 
801 	chip->rtc = devm_rtc_allocate_device(&pdev->dev);
802 	if (IS_ERR(chip->rtc))
803 		return PTR_ERR(chip->rtc);
804 
805 	chip->rtc->ops = &sun6i_rtc_ops;
806 	if (chip->flags & RTC_LINEAR_DAY)
807 		chip->rtc->range_max = (65536 * SECS_PER_DAY) - 1;
808 	else
809 		chip->rtc->range_max = 2019686399LL; /* 2033-12-31 23:59:59 */
810 
811 	ret = devm_rtc_register_device(chip->rtc);
812 	if (ret)
813 		return ret;
814 
815 	dev_info(&pdev->dev, "RTC enabled\n");
816 
817 	return 0;
818 }
819 
820 /*
821  * As far as RTC functionality goes, all models are the same. The
822  * datasheets claim that different models have different number of
823  * registers available for non-volatile storage, but experiments show
824  * that all SoCs have 16 registers available for this purpose.
825  */
826 static const struct of_device_id sun6i_rtc_dt_ids[] = {
827 	{ .compatible = "allwinner,sun6i-a31-rtc" },
828 	{ .compatible = "allwinner,sun8i-a23-rtc" },
829 	{ .compatible = "allwinner,sun8i-h3-rtc" },
830 	{ .compatible = "allwinner,sun8i-r40-rtc" },
831 	{ .compatible = "allwinner,sun8i-v3-rtc" },
832 	{ .compatible = "allwinner,sun50i-h5-rtc" },
833 	{ .compatible = "allwinner,sun50i-h6-rtc" },
834 	{ .compatible = "allwinner,sun50i-h616-rtc",
835 		.data = (void *)RTC_LINEAR_DAY },
836 	{ /* sentinel */ },
837 };
838 MODULE_DEVICE_TABLE(of, sun6i_rtc_dt_ids);
839 
840 static struct platform_driver sun6i_rtc_driver = {
841 	.probe		= sun6i_rtc_probe,
842 	.driver		= {
843 		.name		= "sun6i-rtc",
844 		.of_match_table = sun6i_rtc_dt_ids,
845 		.pm = &sun6i_rtc_pm_ops,
846 	},
847 };
848 builtin_platform_driver(sun6i_rtc_driver);
849