xref: /openbmc/linux/drivers/rtc/rtc-sun6i.c (revision 703e7713)
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 /* General-purpose data */
75 #define SUN6I_GP_DATA				0x0100
76 #define SUN6I_GP_DATA_SIZE			0x20
77 
78 /*
79  * Get date values
80  */
81 #define SUN6I_DATE_GET_DAY_VALUE(x)		((x)  & 0x0000001f)
82 #define SUN6I_DATE_GET_MON_VALUE(x)		(((x) & 0x00000f00) >> 8)
83 #define SUN6I_DATE_GET_YEAR_VALUE(x)		(((x) & 0x003f0000) >> 16)
84 #define SUN6I_LEAP_GET_VALUE(x)			(((x) & 0x00400000) >> 22)
85 
86 /*
87  * Get time values
88  */
89 #define SUN6I_TIME_GET_SEC_VALUE(x)		((x)  & 0x0000003f)
90 #define SUN6I_TIME_GET_MIN_VALUE(x)		(((x) & 0x00003f00) >> 8)
91 #define SUN6I_TIME_GET_HOUR_VALUE(x)		(((x) & 0x001f0000) >> 16)
92 
93 /*
94  * Set date values
95  */
96 #define SUN6I_DATE_SET_DAY_VALUE(x)		((x)       & 0x0000001f)
97 #define SUN6I_DATE_SET_MON_VALUE(x)		((x) <<  8 & 0x00000f00)
98 #define SUN6I_DATE_SET_YEAR_VALUE(x)		((x) << 16 & 0x003f0000)
99 #define SUN6I_LEAP_SET_VALUE(x)			((x) << 22 & 0x00400000)
100 
101 /*
102  * Set time values
103  */
104 #define SUN6I_TIME_SET_SEC_VALUE(x)		((x)       & 0x0000003f)
105 #define SUN6I_TIME_SET_MIN_VALUE(x)		((x) <<  8 & 0x00003f00)
106 #define SUN6I_TIME_SET_HOUR_VALUE(x)		((x) << 16 & 0x001f0000)
107 
108 /*
109  * The year parameter passed to the driver is usually an offset relative to
110  * the year 1900. This macro is used to convert this offset to another one
111  * relative to the minimum year allowed by the hardware.
112  *
113  * The year range is 1970 - 2033. This range is selected to match Allwinner's
114  * driver, even though it is somewhat limited.
115  */
116 #define SUN6I_YEAR_MIN				1970
117 #define SUN6I_YEAR_OFF				(SUN6I_YEAR_MIN - 1900)
118 
119 #define SECS_PER_DAY				(24 * 3600ULL)
120 
121 /*
122  * There are other differences between models, including:
123  *
124  *   - number of GPIO pins that can be configured to hold a certain level
125  *   - crypto-key related registers (H5, H6)
126  *   - boot process related (super standby, secondary processor entry address)
127  *     registers (R40, H6)
128  *   - SYS power domain controls (R40)
129  *   - DCXO controls (H6)
130  *   - RC oscillator calibration (H6)
131  *
132  * These functions are not covered by this driver.
133  */
134 struct sun6i_rtc_clk_data {
135 	unsigned long rc_osc_rate;
136 	unsigned int fixed_prescaler : 16;
137 	unsigned int has_prescaler : 1;
138 	unsigned int has_out_clk : 1;
139 	unsigned int has_losc_en : 1;
140 	unsigned int has_auto_swt : 1;
141 };
142 
143 #define RTC_LINEAR_DAY	BIT(0)
144 
145 struct sun6i_rtc_dev {
146 	struct rtc_device *rtc;
147 	const struct sun6i_rtc_clk_data *data;
148 	void __iomem *base;
149 	int irq;
150 	time64_t alarm;
151 	unsigned long flags;
152 
153 	struct clk_hw hw;
154 	struct clk_hw *int_osc;
155 	struct clk *losc;
156 	struct clk *ext_losc;
157 
158 	spinlock_t lock;
159 };
160 
161 static struct sun6i_rtc_dev *sun6i_rtc;
162 
163 static unsigned long sun6i_rtc_osc_recalc_rate(struct clk_hw *hw,
164 					       unsigned long parent_rate)
165 {
166 	struct sun6i_rtc_dev *rtc = container_of(hw, struct sun6i_rtc_dev, hw);
167 	u32 val = 0;
168 
169 	val = readl(rtc->base + SUN6I_LOSC_CTRL);
170 	if (val & SUN6I_LOSC_CTRL_EXT_OSC)
171 		return parent_rate;
172 
173 	if (rtc->data->fixed_prescaler)
174 		parent_rate /= rtc->data->fixed_prescaler;
175 
176 	if (rtc->data->has_prescaler) {
177 		val = readl(rtc->base + SUN6I_LOSC_CLK_PRESCAL);
178 		val &= GENMASK(4, 0);
179 	}
180 
181 	return parent_rate / (val + 1);
182 }
183 
184 static u8 sun6i_rtc_osc_get_parent(struct clk_hw *hw)
185 {
186 	struct sun6i_rtc_dev *rtc = container_of(hw, struct sun6i_rtc_dev, hw);
187 
188 	return readl(rtc->base + SUN6I_LOSC_CTRL) & SUN6I_LOSC_CTRL_EXT_OSC;
189 }
190 
191 static int sun6i_rtc_osc_set_parent(struct clk_hw *hw, u8 index)
192 {
193 	struct sun6i_rtc_dev *rtc = container_of(hw, struct sun6i_rtc_dev, hw);
194 	unsigned long flags;
195 	u32 val;
196 
197 	if (index > 1)
198 		return -EINVAL;
199 
200 	spin_lock_irqsave(&rtc->lock, flags);
201 	val = readl(rtc->base + SUN6I_LOSC_CTRL);
202 	val &= ~SUN6I_LOSC_CTRL_EXT_OSC;
203 	val |= SUN6I_LOSC_CTRL_KEY;
204 	val |= index ? SUN6I_LOSC_CTRL_EXT_OSC : 0;
205 	if (rtc->data->has_losc_en) {
206 		val &= ~SUN6I_LOSC_CTRL_EXT_LOSC_EN;
207 		val |= index ? SUN6I_LOSC_CTRL_EXT_LOSC_EN : 0;
208 	}
209 	writel(val, rtc->base + SUN6I_LOSC_CTRL);
210 	spin_unlock_irqrestore(&rtc->lock, flags);
211 
212 	return 0;
213 }
214 
215 static const struct clk_ops sun6i_rtc_osc_ops = {
216 	.recalc_rate	= sun6i_rtc_osc_recalc_rate,
217 	.determine_rate	= clk_hw_determine_rate_no_reparent,
218 
219 	.get_parent	= sun6i_rtc_osc_get_parent,
220 	.set_parent	= sun6i_rtc_osc_set_parent,
221 };
222 
223 static void __init sun6i_rtc_clk_init(struct device_node *node,
224 				      const struct sun6i_rtc_clk_data *data)
225 {
226 	struct clk_hw_onecell_data *clk_data;
227 	struct sun6i_rtc_dev *rtc;
228 	struct clk_init_data init = {
229 		.ops		= &sun6i_rtc_osc_ops,
230 		.name		= "losc",
231 	};
232 	const char *iosc_name = "rtc-int-osc";
233 	const char *clkout_name = "osc32k-out";
234 	const char *parents[2];
235 	u32 reg;
236 
237 	rtc = kzalloc(sizeof(*rtc), GFP_KERNEL);
238 	if (!rtc)
239 		return;
240 
241 	rtc->data = data;
242 	clk_data = kzalloc(struct_size(clk_data, hws, 3), GFP_KERNEL);
243 	if (!clk_data) {
244 		kfree(rtc);
245 		return;
246 	}
247 
248 	spin_lock_init(&rtc->lock);
249 
250 	rtc->base = of_io_request_and_map(node, 0, of_node_full_name(node));
251 	if (IS_ERR(rtc->base)) {
252 		pr_crit("Can't map RTC registers");
253 		goto err;
254 	}
255 
256 	reg = SUN6I_LOSC_CTRL_KEY;
257 	if (rtc->data->has_auto_swt) {
258 		/* Bypass auto-switch to int osc, on ext losc failure */
259 		reg |= SUN6I_LOSC_CTRL_AUTO_SWT_BYPASS;
260 		writel(reg, rtc->base + SUN6I_LOSC_CTRL);
261 	}
262 
263 	/* Switch to the external, more precise, oscillator, if present */
264 	if (of_property_present(node, "clocks")) {
265 		reg |= SUN6I_LOSC_CTRL_EXT_OSC;
266 		if (rtc->data->has_losc_en)
267 			reg |= SUN6I_LOSC_CTRL_EXT_LOSC_EN;
268 	}
269 	writel(reg, rtc->base + SUN6I_LOSC_CTRL);
270 
271 	/* Yes, I know, this is ugly. */
272 	sun6i_rtc = rtc;
273 
274 	of_property_read_string_index(node, "clock-output-names", 2,
275 				      &iosc_name);
276 
277 	rtc->int_osc = clk_hw_register_fixed_rate_with_accuracy(NULL,
278 								iosc_name,
279 								NULL, 0,
280 								rtc->data->rc_osc_rate,
281 								300000000);
282 	if (IS_ERR(rtc->int_osc)) {
283 		pr_crit("Couldn't register the internal oscillator\n");
284 		goto err;
285 	}
286 
287 	parents[0] = clk_hw_get_name(rtc->int_osc);
288 	/* If there is no external oscillator, this will be NULL and ... */
289 	parents[1] = of_clk_get_parent_name(node, 0);
290 
291 	rtc->hw.init = &init;
292 
293 	init.parent_names = parents;
294 	/* ... number of clock parents will be 1. */
295 	init.num_parents = of_clk_get_parent_count(node) + 1;
296 	of_property_read_string_index(node, "clock-output-names", 0,
297 				      &init.name);
298 
299 	rtc->losc = clk_register(NULL, &rtc->hw);
300 	if (IS_ERR(rtc->losc)) {
301 		pr_crit("Couldn't register the LOSC clock\n");
302 		goto err_register;
303 	}
304 
305 	of_property_read_string_index(node, "clock-output-names", 1,
306 				      &clkout_name);
307 	rtc->ext_losc = clk_register_gate(NULL, clkout_name, init.name,
308 					  0, rtc->base + SUN6I_LOSC_OUT_GATING,
309 					  SUN6I_LOSC_OUT_GATING_EN_OFFSET, 0,
310 					  &rtc->lock);
311 	if (IS_ERR(rtc->ext_losc)) {
312 		pr_crit("Couldn't register the LOSC external gate\n");
313 		goto err_register;
314 	}
315 
316 	clk_data->num = 3;
317 	clk_data->hws[0] = &rtc->hw;
318 	clk_data->hws[1] = __clk_get_hw(rtc->ext_losc);
319 	clk_data->hws[2] = rtc->int_osc;
320 	of_clk_add_hw_provider(node, of_clk_hw_onecell_get, clk_data);
321 	return;
322 
323 err_register:
324 	clk_hw_unregister_fixed_rate(rtc->int_osc);
325 err:
326 	kfree(clk_data);
327 }
328 
329 static const struct sun6i_rtc_clk_data sun6i_a31_rtc_data = {
330 	.rc_osc_rate = 667000, /* datasheet says 600 ~ 700 KHz */
331 	.has_prescaler = 1,
332 };
333 
334 static void __init sun6i_a31_rtc_clk_init(struct device_node *node)
335 {
336 	sun6i_rtc_clk_init(node, &sun6i_a31_rtc_data);
337 }
338 CLK_OF_DECLARE_DRIVER(sun6i_a31_rtc_clk, "allwinner,sun6i-a31-rtc",
339 		      sun6i_a31_rtc_clk_init);
340 
341 static const struct sun6i_rtc_clk_data sun8i_a23_rtc_data = {
342 	.rc_osc_rate = 667000, /* datasheet says 600 ~ 700 KHz */
343 	.has_prescaler = 1,
344 	.has_out_clk = 1,
345 };
346 
347 static void __init sun8i_a23_rtc_clk_init(struct device_node *node)
348 {
349 	sun6i_rtc_clk_init(node, &sun8i_a23_rtc_data);
350 }
351 CLK_OF_DECLARE_DRIVER(sun8i_a23_rtc_clk, "allwinner,sun8i-a23-rtc",
352 		      sun8i_a23_rtc_clk_init);
353 
354 static const struct sun6i_rtc_clk_data sun8i_h3_rtc_data = {
355 	.rc_osc_rate = 16000000,
356 	.fixed_prescaler = 32,
357 	.has_prescaler = 1,
358 	.has_out_clk = 1,
359 };
360 
361 static void __init sun8i_h3_rtc_clk_init(struct device_node *node)
362 {
363 	sun6i_rtc_clk_init(node, &sun8i_h3_rtc_data);
364 }
365 CLK_OF_DECLARE_DRIVER(sun8i_h3_rtc_clk, "allwinner,sun8i-h3-rtc",
366 		      sun8i_h3_rtc_clk_init);
367 /* As far as we are concerned, clocks for H5 are the same as H3 */
368 CLK_OF_DECLARE_DRIVER(sun50i_h5_rtc_clk, "allwinner,sun50i-h5-rtc",
369 		      sun8i_h3_rtc_clk_init);
370 
371 static const struct sun6i_rtc_clk_data sun50i_h6_rtc_data = {
372 	.rc_osc_rate = 16000000,
373 	.fixed_prescaler = 32,
374 	.has_prescaler = 1,
375 	.has_out_clk = 1,
376 	.has_losc_en = 1,
377 	.has_auto_swt = 1,
378 };
379 
380 static void __init sun50i_h6_rtc_clk_init(struct device_node *node)
381 {
382 	sun6i_rtc_clk_init(node, &sun50i_h6_rtc_data);
383 }
384 CLK_OF_DECLARE_DRIVER(sun50i_h6_rtc_clk, "allwinner,sun50i-h6-rtc",
385 		      sun50i_h6_rtc_clk_init);
386 
387 /*
388  * The R40 user manual is self-conflicting on whether the prescaler is
389  * fixed or configurable. The clock diagram shows it as fixed, but there
390  * is also a configurable divider in the RTC block.
391  */
392 static const struct sun6i_rtc_clk_data sun8i_r40_rtc_data = {
393 	.rc_osc_rate = 16000000,
394 	.fixed_prescaler = 512,
395 };
396 static void __init sun8i_r40_rtc_clk_init(struct device_node *node)
397 {
398 	sun6i_rtc_clk_init(node, &sun8i_r40_rtc_data);
399 }
400 CLK_OF_DECLARE_DRIVER(sun8i_r40_rtc_clk, "allwinner,sun8i-r40-rtc",
401 		      sun8i_r40_rtc_clk_init);
402 
403 static const struct sun6i_rtc_clk_data sun8i_v3_rtc_data = {
404 	.rc_osc_rate = 32000,
405 	.has_out_clk = 1,
406 };
407 
408 static void __init sun8i_v3_rtc_clk_init(struct device_node *node)
409 {
410 	sun6i_rtc_clk_init(node, &sun8i_v3_rtc_data);
411 }
412 CLK_OF_DECLARE_DRIVER(sun8i_v3_rtc_clk, "allwinner,sun8i-v3-rtc",
413 		      sun8i_v3_rtc_clk_init);
414 
415 static irqreturn_t sun6i_rtc_alarmirq(int irq, void *id)
416 {
417 	struct sun6i_rtc_dev *chip = (struct sun6i_rtc_dev *) id;
418 	irqreturn_t ret = IRQ_NONE;
419 	u32 val;
420 
421 	spin_lock(&chip->lock);
422 	val = readl(chip->base + SUN6I_ALRM_IRQ_STA);
423 
424 	if (val & SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND) {
425 		val |= SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND;
426 		writel(val, chip->base + SUN6I_ALRM_IRQ_STA);
427 
428 		rtc_update_irq(chip->rtc, 1, RTC_AF | RTC_IRQF);
429 
430 		ret = IRQ_HANDLED;
431 	}
432 	spin_unlock(&chip->lock);
433 
434 	return ret;
435 }
436 
437 static void sun6i_rtc_setaie(int to, struct sun6i_rtc_dev *chip)
438 {
439 	u32 alrm_val = 0;
440 	u32 alrm_irq_val = 0;
441 	u32 alrm_wake_val = 0;
442 	unsigned long flags;
443 
444 	if (to) {
445 		alrm_val = SUN6I_ALRM_EN_CNT_EN;
446 		alrm_irq_val = SUN6I_ALRM_IRQ_EN_CNT_IRQ_EN;
447 		alrm_wake_val = SUN6I_ALARM_CONFIG_WAKEUP;
448 	} else {
449 		writel(SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND,
450 		       chip->base + SUN6I_ALRM_IRQ_STA);
451 	}
452 
453 	spin_lock_irqsave(&chip->lock, flags);
454 	writel(alrm_val, chip->base + SUN6I_ALRM_EN);
455 	writel(alrm_irq_val, chip->base + SUN6I_ALRM_IRQ_EN);
456 	writel(alrm_wake_val, chip->base + SUN6I_ALARM_CONFIG);
457 	spin_unlock_irqrestore(&chip->lock, flags);
458 }
459 
460 static int sun6i_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
461 {
462 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
463 	u32 date, time;
464 
465 	/*
466 	 * read again in case it changes
467 	 */
468 	do {
469 		date = readl(chip->base + SUN6I_RTC_YMD);
470 		time = readl(chip->base + SUN6I_RTC_HMS);
471 	} while ((date != readl(chip->base + SUN6I_RTC_YMD)) ||
472 		 (time != readl(chip->base + SUN6I_RTC_HMS)));
473 
474 	if (chip->flags & RTC_LINEAR_DAY) {
475 		/*
476 		 * Newer chips store a linear day number, the manual
477 		 * does not mandate any epoch base. The BSP driver uses
478 		 * the UNIX epoch, let's just copy that, as it's the
479 		 * easiest anyway.
480 		 */
481 		rtc_time64_to_tm((date & 0xffff) * SECS_PER_DAY, rtc_tm);
482 	} else {
483 		rtc_tm->tm_mday = SUN6I_DATE_GET_DAY_VALUE(date);
484 		rtc_tm->tm_mon  = SUN6I_DATE_GET_MON_VALUE(date) - 1;
485 		rtc_tm->tm_year = SUN6I_DATE_GET_YEAR_VALUE(date);
486 
487 		/*
488 		 * switch from (data_year->min)-relative offset to
489 		 * a (1900)-relative one
490 		 */
491 		rtc_tm->tm_year += SUN6I_YEAR_OFF;
492 	}
493 
494 	rtc_tm->tm_sec  = SUN6I_TIME_GET_SEC_VALUE(time);
495 	rtc_tm->tm_min  = SUN6I_TIME_GET_MIN_VALUE(time);
496 	rtc_tm->tm_hour = SUN6I_TIME_GET_HOUR_VALUE(time);
497 
498 	return 0;
499 }
500 
501 static int sun6i_rtc_getalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
502 {
503 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
504 	unsigned long flags;
505 	u32 alrm_st;
506 	u32 alrm_en;
507 
508 	spin_lock_irqsave(&chip->lock, flags);
509 	alrm_en = readl(chip->base + SUN6I_ALRM_IRQ_EN);
510 	alrm_st = readl(chip->base + SUN6I_ALRM_IRQ_STA);
511 	spin_unlock_irqrestore(&chip->lock, flags);
512 
513 	wkalrm->enabled = !!(alrm_en & SUN6I_ALRM_EN_CNT_EN);
514 	wkalrm->pending = !!(alrm_st & SUN6I_ALRM_EN_CNT_EN);
515 	rtc_time64_to_tm(chip->alarm, &wkalrm->time);
516 
517 	return 0;
518 }
519 
520 static int sun6i_rtc_setalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
521 {
522 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
523 	struct rtc_time *alrm_tm = &wkalrm->time;
524 	struct rtc_time tm_now;
525 	time64_t time_set;
526 	u32 counter_val, counter_val_hms;
527 	int ret;
528 
529 	time_set = rtc_tm_to_time64(alrm_tm);
530 
531 	if (chip->flags & RTC_LINEAR_DAY) {
532 		/*
533 		 * The alarm registers hold the actual alarm time, encoded
534 		 * in the same way (linear day + HMS) as the current time.
535 		 */
536 		counter_val_hms = SUN6I_TIME_SET_SEC_VALUE(alrm_tm->tm_sec)  |
537 				  SUN6I_TIME_SET_MIN_VALUE(alrm_tm->tm_min)  |
538 				  SUN6I_TIME_SET_HOUR_VALUE(alrm_tm->tm_hour);
539 		/* The division will cut off the H:M:S part of alrm_tm. */
540 		counter_val = div_u64(rtc_tm_to_time64(alrm_tm), SECS_PER_DAY);
541 	} else {
542 		/* The alarm register holds the number of seconds left. */
543 		time64_t time_now;
544 
545 		ret = sun6i_rtc_gettime(dev, &tm_now);
546 		if (ret < 0) {
547 			dev_err(dev, "Error in getting time\n");
548 			return -EINVAL;
549 		}
550 
551 		time_now = rtc_tm_to_time64(&tm_now);
552 		if (time_set <= time_now) {
553 			dev_err(dev, "Date to set in the past\n");
554 			return -EINVAL;
555 		}
556 		if ((time_set - time_now) > U32_MAX) {
557 			dev_err(dev, "Date too far in the future\n");
558 			return -EINVAL;
559 		}
560 
561 		counter_val = time_set - time_now;
562 	}
563 
564 	sun6i_rtc_setaie(0, chip);
565 	writel(0, chip->base + SUN6I_ALRM_COUNTER);
566 	if (chip->flags & RTC_LINEAR_DAY)
567 		writel(0, chip->base + SUN6I_ALRM_COUNTER_HMS);
568 	usleep_range(100, 300);
569 
570 	writel(counter_val, chip->base + SUN6I_ALRM_COUNTER);
571 	if (chip->flags & RTC_LINEAR_DAY)
572 		writel(counter_val_hms, chip->base + SUN6I_ALRM_COUNTER_HMS);
573 	chip->alarm = time_set;
574 
575 	sun6i_rtc_setaie(wkalrm->enabled, chip);
576 
577 	return 0;
578 }
579 
580 static int sun6i_rtc_wait(struct sun6i_rtc_dev *chip, int offset,
581 			  unsigned int mask, unsigned int ms_timeout)
582 {
583 	const unsigned long timeout = jiffies + msecs_to_jiffies(ms_timeout);
584 	u32 reg;
585 
586 	do {
587 		reg = readl(chip->base + offset);
588 		reg &= mask;
589 
590 		if (!reg)
591 			return 0;
592 
593 	} while (time_before(jiffies, timeout));
594 
595 	return -ETIMEDOUT;
596 }
597 
598 static int sun6i_rtc_settime(struct device *dev, struct rtc_time *rtc_tm)
599 {
600 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
601 	u32 date = 0;
602 	u32 time = 0;
603 
604 	time = SUN6I_TIME_SET_SEC_VALUE(rtc_tm->tm_sec)  |
605 		SUN6I_TIME_SET_MIN_VALUE(rtc_tm->tm_min)  |
606 		SUN6I_TIME_SET_HOUR_VALUE(rtc_tm->tm_hour);
607 
608 	if (chip->flags & RTC_LINEAR_DAY) {
609 		/* The division will cut off the H:M:S part of rtc_tm. */
610 		date = div_u64(rtc_tm_to_time64(rtc_tm), SECS_PER_DAY);
611 	} else {
612 		rtc_tm->tm_year -= SUN6I_YEAR_OFF;
613 		rtc_tm->tm_mon += 1;
614 
615 		date = SUN6I_DATE_SET_DAY_VALUE(rtc_tm->tm_mday) |
616 			SUN6I_DATE_SET_MON_VALUE(rtc_tm->tm_mon)  |
617 			SUN6I_DATE_SET_YEAR_VALUE(rtc_tm->tm_year);
618 
619 		if (is_leap_year(rtc_tm->tm_year + SUN6I_YEAR_MIN))
620 			date |= SUN6I_LEAP_SET_VALUE(1);
621 	}
622 
623 	/* Check whether registers are writable */
624 	if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
625 			   SUN6I_LOSC_CTRL_ACC_MASK, 50)) {
626 		dev_err(dev, "rtc is still busy.\n");
627 		return -EBUSY;
628 	}
629 
630 	writel(time, chip->base + SUN6I_RTC_HMS);
631 
632 	/*
633 	 * After writing the RTC HH-MM-SS register, the
634 	 * SUN6I_LOSC_CTRL_RTC_HMS_ACC bit is set and it will not
635 	 * be cleared until the real writing operation is finished
636 	 */
637 
638 	if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
639 			   SUN6I_LOSC_CTRL_RTC_HMS_ACC, 50)) {
640 		dev_err(dev, "Failed to set rtc time.\n");
641 		return -ETIMEDOUT;
642 	}
643 
644 	writel(date, chip->base + SUN6I_RTC_YMD);
645 
646 	/*
647 	 * After writing the RTC YY-MM-DD register, the
648 	 * SUN6I_LOSC_CTRL_RTC_YMD_ACC bit is set and it will not
649 	 * be cleared until the real writing operation is finished
650 	 */
651 
652 	if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
653 			   SUN6I_LOSC_CTRL_RTC_YMD_ACC, 50)) {
654 		dev_err(dev, "Failed to set rtc time.\n");
655 		return -ETIMEDOUT;
656 	}
657 
658 	return 0;
659 }
660 
661 static int sun6i_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
662 {
663 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
664 
665 	if (!enabled)
666 		sun6i_rtc_setaie(enabled, chip);
667 
668 	return 0;
669 }
670 
671 static const struct rtc_class_ops sun6i_rtc_ops = {
672 	.read_time		= sun6i_rtc_gettime,
673 	.set_time		= sun6i_rtc_settime,
674 	.read_alarm		= sun6i_rtc_getalarm,
675 	.set_alarm		= sun6i_rtc_setalarm,
676 	.alarm_irq_enable	= sun6i_rtc_alarm_irq_enable
677 };
678 
679 static int sun6i_rtc_nvmem_read(void *priv, unsigned int offset, void *_val, size_t bytes)
680 {
681 	struct sun6i_rtc_dev *chip = priv;
682 	u32 *val = _val;
683 	int i;
684 
685 	for (i = 0; i < bytes / 4; ++i)
686 		val[i] = readl(chip->base + SUN6I_GP_DATA + offset + 4 * i);
687 
688 	return 0;
689 }
690 
691 static int sun6i_rtc_nvmem_write(void *priv, unsigned int offset, void *_val, size_t bytes)
692 {
693 	struct sun6i_rtc_dev *chip = priv;
694 	u32 *val = _val;
695 	int i;
696 
697 	for (i = 0; i < bytes / 4; ++i)
698 		writel(val[i], chip->base + SUN6I_GP_DATA + offset + 4 * i);
699 
700 	return 0;
701 }
702 
703 static struct nvmem_config sun6i_rtc_nvmem_cfg = {
704 	.type		= NVMEM_TYPE_BATTERY_BACKED,
705 	.reg_read	= sun6i_rtc_nvmem_read,
706 	.reg_write	= sun6i_rtc_nvmem_write,
707 	.size		= SUN6I_GP_DATA_SIZE,
708 	.word_size	= 4,
709 	.stride		= 4,
710 };
711 
712 #ifdef CONFIG_PM_SLEEP
713 /* Enable IRQ wake on suspend, to wake up from RTC. */
714 static int sun6i_rtc_suspend(struct device *dev)
715 {
716 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
717 
718 	if (device_may_wakeup(dev))
719 		enable_irq_wake(chip->irq);
720 
721 	return 0;
722 }
723 
724 /* Disable IRQ wake on resume. */
725 static int sun6i_rtc_resume(struct device *dev)
726 {
727 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
728 
729 	if (device_may_wakeup(dev))
730 		disable_irq_wake(chip->irq);
731 
732 	return 0;
733 }
734 #endif
735 
736 static SIMPLE_DEV_PM_OPS(sun6i_rtc_pm_ops,
737 	sun6i_rtc_suspend, sun6i_rtc_resume);
738 
739 static void sun6i_rtc_bus_clk_cleanup(void *data)
740 {
741 	struct clk *bus_clk = data;
742 
743 	clk_disable_unprepare(bus_clk);
744 }
745 
746 static int sun6i_rtc_probe(struct platform_device *pdev)
747 {
748 	struct sun6i_rtc_dev *chip = sun6i_rtc;
749 	struct device *dev = &pdev->dev;
750 	struct clk *bus_clk;
751 	int ret;
752 
753 	bus_clk = devm_clk_get_optional(dev, "bus");
754 	if (IS_ERR(bus_clk))
755 		return PTR_ERR(bus_clk);
756 
757 	if (bus_clk) {
758 		ret = clk_prepare_enable(bus_clk);
759 		if (ret)
760 			return ret;
761 
762 		ret = devm_add_action_or_reset(dev, sun6i_rtc_bus_clk_cleanup,
763 					       bus_clk);
764 		if (ret)
765 			return ret;
766 	}
767 
768 	if (!chip) {
769 		chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
770 		if (!chip)
771 			return -ENOMEM;
772 
773 		spin_lock_init(&chip->lock);
774 
775 		chip->base = devm_platform_ioremap_resource(pdev, 0);
776 		if (IS_ERR(chip->base))
777 			return PTR_ERR(chip->base);
778 
779 		if (IS_REACHABLE(CONFIG_SUN6I_RTC_CCU)) {
780 			ret = sun6i_rtc_ccu_probe(dev, chip->base);
781 			if (ret)
782 				return ret;
783 		}
784 	}
785 
786 	platform_set_drvdata(pdev, chip);
787 
788 	chip->flags = (unsigned long)of_device_get_match_data(&pdev->dev);
789 
790 	chip->irq = platform_get_irq(pdev, 0);
791 	if (chip->irq < 0)
792 		return chip->irq;
793 
794 	ret = devm_request_irq(&pdev->dev, chip->irq, sun6i_rtc_alarmirq,
795 			       0, dev_name(&pdev->dev), chip);
796 	if (ret) {
797 		dev_err(&pdev->dev, "Could not request IRQ\n");
798 		return ret;
799 	}
800 
801 	/* clear the alarm counter value */
802 	writel(0, chip->base + SUN6I_ALRM_COUNTER);
803 
804 	/* disable counter alarm */
805 	writel(0, chip->base + SUN6I_ALRM_EN);
806 
807 	/* disable counter alarm interrupt */
808 	writel(0, chip->base + SUN6I_ALRM_IRQ_EN);
809 
810 	/* disable week alarm */
811 	writel(0, chip->base + SUN6I_ALRM1_EN);
812 
813 	/* disable week alarm interrupt */
814 	writel(0, chip->base + SUN6I_ALRM1_IRQ_EN);
815 
816 	/* clear counter alarm pending interrupts */
817 	writel(SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND,
818 	       chip->base + SUN6I_ALRM_IRQ_STA);
819 
820 	/* clear week alarm pending interrupts */
821 	writel(SUN6I_ALRM1_IRQ_STA_WEEK_IRQ_PEND,
822 	       chip->base + SUN6I_ALRM1_IRQ_STA);
823 
824 	/* disable alarm wakeup */
825 	writel(0, chip->base + SUN6I_ALARM_CONFIG);
826 
827 	clk_prepare_enable(chip->losc);
828 
829 	device_init_wakeup(&pdev->dev, 1);
830 
831 	chip->rtc = devm_rtc_allocate_device(&pdev->dev);
832 	if (IS_ERR(chip->rtc))
833 		return PTR_ERR(chip->rtc);
834 
835 	chip->rtc->ops = &sun6i_rtc_ops;
836 	if (chip->flags & RTC_LINEAR_DAY)
837 		chip->rtc->range_max = (65536 * SECS_PER_DAY) - 1;
838 	else
839 		chip->rtc->range_max = 2019686399LL; /* 2033-12-31 23:59:59 */
840 
841 	ret = devm_rtc_register_device(chip->rtc);
842 	if (ret)
843 		return ret;
844 
845 	sun6i_rtc_nvmem_cfg.priv = chip;
846 	ret = devm_rtc_nvmem_register(chip->rtc, &sun6i_rtc_nvmem_cfg);
847 	if (ret)
848 		return ret;
849 
850 	dev_info(&pdev->dev, "RTC enabled\n");
851 
852 	return 0;
853 }
854 
855 /*
856  * As far as RTC functionality goes, all models are the same. The
857  * datasheets claim that different models have different number of
858  * registers available for non-volatile storage, but experiments show
859  * that all SoCs have 16 registers available for this purpose.
860  */
861 static const struct of_device_id sun6i_rtc_dt_ids[] = {
862 	{ .compatible = "allwinner,sun6i-a31-rtc" },
863 	{ .compatible = "allwinner,sun8i-a23-rtc" },
864 	{ .compatible = "allwinner,sun8i-h3-rtc" },
865 	{ .compatible = "allwinner,sun8i-r40-rtc" },
866 	{ .compatible = "allwinner,sun8i-v3-rtc" },
867 	{ .compatible = "allwinner,sun50i-h5-rtc" },
868 	{ .compatible = "allwinner,sun50i-h6-rtc" },
869 	{ .compatible = "allwinner,sun50i-h616-rtc",
870 		.data = (void *)RTC_LINEAR_DAY },
871 	{ .compatible = "allwinner,sun50i-r329-rtc",
872 		.data = (void *)RTC_LINEAR_DAY },
873 	{ /* sentinel */ },
874 };
875 MODULE_DEVICE_TABLE(of, sun6i_rtc_dt_ids);
876 
877 static struct platform_driver sun6i_rtc_driver = {
878 	.probe		= sun6i_rtc_probe,
879 	.driver		= {
880 		.name		= "sun6i-rtc",
881 		.of_match_table = sun6i_rtc_dt_ids,
882 		.pm = &sun6i_rtc_pm_ops,
883 	},
884 };
885 builtin_platform_driver(sun6i_rtc_driver);
886