1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * RTC Driver for X-Powers AC100
4 *
5 * Copyright (c) 2016 Chen-Yu Tsai
6 *
7 * Chen-Yu Tsai <wens@csie.org>
8 */
9
10#include <linux/bcd.h>
11#include <linux/clk-provider.h>
12#include <linux/device.h>
13#include <linux/interrupt.h>
14#include <linux/kernel.h>
15#include <linux/mfd/ac100.h>
16#include <linux/module.h>
17#include <linux/mutex.h>
18#include <linux/of.h>
19#include <linux/platform_device.h>
20#include <linux/regmap.h>
21#include <linux/rtc.h>
22#include <linux/types.h>
23
24/* Control register */
25#define AC100_RTC_CTRL_24HOUR	BIT(0)
26
27/* Clock output register bits */
28#define AC100_CLKOUT_PRE_DIV_SHIFT	5
29#define AC100_CLKOUT_PRE_DIV_WIDTH	3
30#define AC100_CLKOUT_MUX_SHIFT		4
31#define AC100_CLKOUT_MUX_WIDTH		1
32#define AC100_CLKOUT_DIV_SHIFT		1
33#define AC100_CLKOUT_DIV_WIDTH		3
34#define AC100_CLKOUT_EN			BIT(0)
35
36/* RTC */
37#define AC100_RTC_SEC_MASK	GENMASK(6, 0)
38#define AC100_RTC_MIN_MASK	GENMASK(6, 0)
39#define AC100_RTC_HOU_MASK	GENMASK(5, 0)
40#define AC100_RTC_WEE_MASK	GENMASK(2, 0)
41#define AC100_RTC_DAY_MASK	GENMASK(5, 0)
42#define AC100_RTC_MON_MASK	GENMASK(4, 0)
43#define AC100_RTC_YEA_MASK	GENMASK(7, 0)
44#define AC100_RTC_YEA_LEAP	BIT(15)
45#define AC100_RTC_UPD_TRIGGER	BIT(15)
46
47/* Alarm (wall clock) */
48#define AC100_ALM_INT_ENABLE	BIT(0)
49
50#define AC100_ALM_SEC_MASK	GENMASK(6, 0)
51#define AC100_ALM_MIN_MASK	GENMASK(6, 0)
52#define AC100_ALM_HOU_MASK	GENMASK(5, 0)
53#define AC100_ALM_WEE_MASK	GENMASK(2, 0)
54#define AC100_ALM_DAY_MASK	GENMASK(5, 0)
55#define AC100_ALM_MON_MASK	GENMASK(4, 0)
56#define AC100_ALM_YEA_MASK	GENMASK(7, 0)
57#define AC100_ALM_ENABLE_FLAG	BIT(15)
58#define AC100_ALM_UPD_TRIGGER	BIT(15)
59
60/*
61 * The year parameter passed to the driver is usually an offset relative to
62 * the year 1900. This macro is used to convert this offset to another one
63 * relative to the minimum year allowed by the hardware.
64 *
65 * The year range is 1970 - 2069. This range is selected to match Allwinner's
66 * driver.
67 */
68#define AC100_YEAR_MIN				1970
69#define AC100_YEAR_MAX				2069
70#define AC100_YEAR_OFF				(AC100_YEAR_MIN - 1900)
71
72struct ac100_clkout {
73	struct clk_hw hw;
74	struct regmap *regmap;
75	u8 offset;
76};
77
78#define to_ac100_clkout(_hw) container_of(_hw, struct ac100_clkout, hw)
79
80#define AC100_RTC_32K_NAME	"ac100-rtc-32k"
81#define AC100_RTC_32K_RATE	32768
82#define AC100_CLKOUT_NUM	3
83
84static const char * const ac100_clkout_names[AC100_CLKOUT_NUM] = {
85	"ac100-cko1-rtc",
86	"ac100-cko2-rtc",
87	"ac100-cko3-rtc",
88};
89
90struct ac100_rtc_dev {
91	struct rtc_device *rtc;
92	struct device *dev;
93	struct regmap *regmap;
94	int irq;
95	unsigned long alarm;
96
97	struct clk_hw *rtc_32k_clk;
98	struct ac100_clkout clks[AC100_CLKOUT_NUM];
99	struct clk_hw_onecell_data *clk_data;
100};
101
102/*
103 * Clock controls for 3 clock output pins
104 */
105
106static const struct clk_div_table ac100_clkout_prediv[] = {
107	{ .val = 0, .div = 1 },
108	{ .val = 1, .div = 2 },
109	{ .val = 2, .div = 4 },
110	{ .val = 3, .div = 8 },
111	{ .val = 4, .div = 16 },
112	{ .val = 5, .div = 32 },
113	{ .val = 6, .div = 64 },
114	{ .val = 7, .div = 122 },
115	{ },
116};
117
118/* Abuse the fact that one parent is 32768 Hz, and the other is 4 MHz */
119static unsigned long ac100_clkout_recalc_rate(struct clk_hw *hw,
120					      unsigned long prate)
121{
122	struct ac100_clkout *clk = to_ac100_clkout(hw);
123	unsigned int reg, div;
124
125	regmap_read(clk->regmap, clk->offset, &reg);
126
127	/* Handle pre-divider first */
128	if (prate != AC100_RTC_32K_RATE) {
129		div = (reg >> AC100_CLKOUT_PRE_DIV_SHIFT) &
130			((1 << AC100_CLKOUT_PRE_DIV_WIDTH) - 1);
131		prate = divider_recalc_rate(hw, prate, div,
132					    ac100_clkout_prediv, 0,
133					    AC100_CLKOUT_PRE_DIV_WIDTH);
134	}
135
136	div = (reg >> AC100_CLKOUT_DIV_SHIFT) &
137		(BIT(AC100_CLKOUT_DIV_WIDTH) - 1);
138	return divider_recalc_rate(hw, prate, div, NULL,
139				   CLK_DIVIDER_POWER_OF_TWO,
140				   AC100_CLKOUT_DIV_WIDTH);
141}
142
143static long ac100_clkout_round_rate(struct clk_hw *hw, unsigned long rate,
144				    unsigned long prate)
145{
146	unsigned long best_rate = 0, tmp_rate, tmp_prate;
147	int i;
148
149	if (prate == AC100_RTC_32K_RATE)
150		return divider_round_rate(hw, rate, &prate, NULL,
151					  AC100_CLKOUT_DIV_WIDTH,
152					  CLK_DIVIDER_POWER_OF_TWO);
153
154	for (i = 0; ac100_clkout_prediv[i].div; i++) {
155		tmp_prate = DIV_ROUND_UP(prate, ac100_clkout_prediv[i].val);
156		tmp_rate = divider_round_rate(hw, rate, &tmp_prate, NULL,
157					      AC100_CLKOUT_DIV_WIDTH,
158					      CLK_DIVIDER_POWER_OF_TWO);
159
160		if (tmp_rate > rate)
161			continue;
162		if (rate - tmp_rate < best_rate - tmp_rate)
163			best_rate = tmp_rate;
164	}
165
166	return best_rate;
167}
168
169static int ac100_clkout_determine_rate(struct clk_hw *hw,
170				       struct clk_rate_request *req)
171{
172	struct clk_hw *best_parent;
173	unsigned long best = 0;
174	int i, num_parents = clk_hw_get_num_parents(hw);
175
176	for (i = 0; i < num_parents; i++) {
177		struct clk_hw *parent = clk_hw_get_parent_by_index(hw, i);
178		unsigned long tmp, prate;
179
180		/*
181		 * The clock has two parents, one is a fixed clock which is
182		 * internally registered by the ac100 driver. The other parent
183		 * is a clock from the codec side of the chip, which we
184		 * properly declare and reference in the devicetree and is
185		 * not implemented in any driver right now.
186		 * If the clock core looks for the parent of that second
187		 * missing clock, it can't find one that is registered and
188		 * returns NULL.
189		 * So we end up in a situation where clk_hw_get_num_parents
190		 * returns the amount of clocks we can be parented to, but
191		 * clk_hw_get_parent_by_index will not return the orphan
192		 * clocks.
193		 * Thus we need to check if the parent exists before
194		 * we get the parent rate, so we could use the RTC
195		 * without waiting for the codec to be supported.
196		 */
197		if (!parent)
198			continue;
199
200		prate = clk_hw_get_rate(parent);
201
202		tmp = ac100_clkout_round_rate(hw, req->rate, prate);
203
204		if (tmp > req->rate)
205			continue;
206		if (req->rate - tmp < req->rate - best) {
207			best = tmp;
208			best_parent = parent;
209		}
210	}
211
212	if (!best)
213		return -EINVAL;
214
215	req->best_parent_hw = best_parent;
216	req->best_parent_rate = best;
217	req->rate = best;
218
219	return 0;
220}
221
222static int ac100_clkout_set_rate(struct clk_hw *hw, unsigned long rate,
223				 unsigned long prate)
224{
225	struct ac100_clkout *clk = to_ac100_clkout(hw);
226	int div = 0, pre_div = 0;
227
228	do {
229		div = divider_get_val(rate * ac100_clkout_prediv[pre_div].div,
230				      prate, NULL, AC100_CLKOUT_DIV_WIDTH,
231				      CLK_DIVIDER_POWER_OF_TWO);
232		if (div >= 0)
233			break;
234	} while (prate != AC100_RTC_32K_RATE &&
235		 ac100_clkout_prediv[++pre_div].div);
236
237	if (div < 0)
238		return div;
239
240	pre_div = ac100_clkout_prediv[pre_div].val;
241
242	regmap_update_bits(clk->regmap, clk->offset,
243			   ((1 << AC100_CLKOUT_DIV_WIDTH) - 1) << AC100_CLKOUT_DIV_SHIFT |
244			   ((1 << AC100_CLKOUT_PRE_DIV_WIDTH) - 1) << AC100_CLKOUT_PRE_DIV_SHIFT,
245			   (div - 1) << AC100_CLKOUT_DIV_SHIFT |
246			   (pre_div - 1) << AC100_CLKOUT_PRE_DIV_SHIFT);
247
248	return 0;
249}
250
251static int ac100_clkout_prepare(struct clk_hw *hw)
252{
253	struct ac100_clkout *clk = to_ac100_clkout(hw);
254
255	return regmap_update_bits(clk->regmap, clk->offset, AC100_CLKOUT_EN,
256				  AC100_CLKOUT_EN);
257}
258
259static void ac100_clkout_unprepare(struct clk_hw *hw)
260{
261	struct ac100_clkout *clk = to_ac100_clkout(hw);
262
263	regmap_update_bits(clk->regmap, clk->offset, AC100_CLKOUT_EN, 0);
264}
265
266static int ac100_clkout_is_prepared(struct clk_hw *hw)
267{
268	struct ac100_clkout *clk = to_ac100_clkout(hw);
269	unsigned int reg;
270
271	regmap_read(clk->regmap, clk->offset, &reg);
272
273	return reg & AC100_CLKOUT_EN;
274}
275
276static u8 ac100_clkout_get_parent(struct clk_hw *hw)
277{
278	struct ac100_clkout *clk = to_ac100_clkout(hw);
279	unsigned int reg;
280
281	regmap_read(clk->regmap, clk->offset, &reg);
282
283	return (reg >> AC100_CLKOUT_MUX_SHIFT) & 0x1;
284}
285
286static int ac100_clkout_set_parent(struct clk_hw *hw, u8 index)
287{
288	struct ac100_clkout *clk = to_ac100_clkout(hw);
289
290	return regmap_update_bits(clk->regmap, clk->offset,
291				  BIT(AC100_CLKOUT_MUX_SHIFT),
292				  index ? BIT(AC100_CLKOUT_MUX_SHIFT) : 0);
293}
294
295static const struct clk_ops ac100_clkout_ops = {
296	.prepare	= ac100_clkout_prepare,
297	.unprepare	= ac100_clkout_unprepare,
298	.is_prepared	= ac100_clkout_is_prepared,
299	.recalc_rate	= ac100_clkout_recalc_rate,
300	.determine_rate	= ac100_clkout_determine_rate,
301	.get_parent	= ac100_clkout_get_parent,
302	.set_parent	= ac100_clkout_set_parent,
303	.set_rate	= ac100_clkout_set_rate,
304};
305
306static int ac100_rtc_register_clks(struct ac100_rtc_dev *chip)
307{
308	struct device_node *np = chip->dev->of_node;
309	const char *parents[2] = {AC100_RTC_32K_NAME};
310	int i, ret;
311
312	chip->clk_data = devm_kzalloc(chip->dev,
313				      struct_size(chip->clk_data, hws,
314						  AC100_CLKOUT_NUM),
315				      GFP_KERNEL);
316	if (!chip->clk_data)
317		return -ENOMEM;
318
319	chip->rtc_32k_clk = clk_hw_register_fixed_rate(chip->dev,
320						       AC100_RTC_32K_NAME,
321						       NULL, 0,
322						       AC100_RTC_32K_RATE);
323	if (IS_ERR(chip->rtc_32k_clk)) {
324		ret = PTR_ERR(chip->rtc_32k_clk);
325		dev_err(chip->dev, "Failed to register RTC-32k clock: %d\n",
326			ret);
327		return ret;
328	}
329
330	parents[1] = of_clk_get_parent_name(np, 0);
331	if (!parents[1]) {
332		dev_err(chip->dev, "Failed to get ADDA 4M clock\n");
333		return -EINVAL;
334	}
335
336	for (i = 0; i < AC100_CLKOUT_NUM; i++) {
337		struct ac100_clkout *clk = &chip->clks[i];
338		struct clk_init_data init = {
339			.name = ac100_clkout_names[i],
340			.ops = &ac100_clkout_ops,
341			.parent_names = parents,
342			.num_parents = ARRAY_SIZE(parents),
343			.flags = 0,
344		};
345
346		of_property_read_string_index(np, "clock-output-names",
347					      i, &init.name);
348		clk->regmap = chip->regmap;
349		clk->offset = AC100_CLKOUT_CTRL1 + i;
350		clk->hw.init = &init;
351
352		ret = devm_clk_hw_register(chip->dev, &clk->hw);
353		if (ret) {
354			dev_err(chip->dev, "Failed to register clk '%s': %d\n",
355				init.name, ret);
356			goto err_unregister_rtc_32k;
357		}
358
359		chip->clk_data->hws[i] = &clk->hw;
360	}
361
362	chip->clk_data->num = i;
363	ret = of_clk_add_hw_provider(np, of_clk_hw_onecell_get, chip->clk_data);
364	if (ret)
365		goto err_unregister_rtc_32k;
366
367	return 0;
368
369err_unregister_rtc_32k:
370	clk_unregister_fixed_rate(chip->rtc_32k_clk->clk);
371
372	return ret;
373}
374
375static void ac100_rtc_unregister_clks(struct ac100_rtc_dev *chip)
376{
377	of_clk_del_provider(chip->dev->of_node);
378	clk_unregister_fixed_rate(chip->rtc_32k_clk->clk);
379}
380
381/*
382 * RTC related bits
383 */
384static int ac100_rtc_get_time(struct device *dev, struct rtc_time *rtc_tm)
385{
386	struct ac100_rtc_dev *chip = dev_get_drvdata(dev);
387	struct regmap *regmap = chip->regmap;
388	u16 reg[7];
389	int ret;
390
391	ret = regmap_bulk_read(regmap, AC100_RTC_SEC, reg, 7);
392	if (ret)
393		return ret;
394
395	rtc_tm->tm_sec  = bcd2bin(reg[0] & AC100_RTC_SEC_MASK);
396	rtc_tm->tm_min  = bcd2bin(reg[1] & AC100_RTC_MIN_MASK);
397	rtc_tm->tm_hour = bcd2bin(reg[2] & AC100_RTC_HOU_MASK);
398	rtc_tm->tm_wday = bcd2bin(reg[3] & AC100_RTC_WEE_MASK);
399	rtc_tm->tm_mday = bcd2bin(reg[4] & AC100_RTC_DAY_MASK);
400	rtc_tm->tm_mon  = bcd2bin(reg[5] & AC100_RTC_MON_MASK) - 1;
401	rtc_tm->tm_year = bcd2bin(reg[6] & AC100_RTC_YEA_MASK) +
402			  AC100_YEAR_OFF;
403
404	return 0;
405}
406
407static int ac100_rtc_set_time(struct device *dev, struct rtc_time *rtc_tm)
408{
409	struct ac100_rtc_dev *chip = dev_get_drvdata(dev);
410	struct regmap *regmap = chip->regmap;
411	int year;
412	u16 reg[8];
413
414	/* our RTC has a limited year range... */
415	year = rtc_tm->tm_year - AC100_YEAR_OFF;
416	if (year < 0 || year > (AC100_YEAR_MAX - 1900)) {
417		dev_err(dev, "rtc only supports year in range %d - %d\n",
418			AC100_YEAR_MIN, AC100_YEAR_MAX);
419		return -EINVAL;
420	}
421
422	/* convert to BCD */
423	reg[0] = bin2bcd(rtc_tm->tm_sec)     & AC100_RTC_SEC_MASK;
424	reg[1] = bin2bcd(rtc_tm->tm_min)     & AC100_RTC_MIN_MASK;
425	reg[2] = bin2bcd(rtc_tm->tm_hour)    & AC100_RTC_HOU_MASK;
426	reg[3] = bin2bcd(rtc_tm->tm_wday)    & AC100_RTC_WEE_MASK;
427	reg[4] = bin2bcd(rtc_tm->tm_mday)    & AC100_RTC_DAY_MASK;
428	reg[5] = bin2bcd(rtc_tm->tm_mon + 1) & AC100_RTC_MON_MASK;
429	reg[6] = bin2bcd(year)		     & AC100_RTC_YEA_MASK;
430	/* trigger write */
431	reg[7] = AC100_RTC_UPD_TRIGGER;
432
433	/* Is it a leap year? */
434	if (is_leap_year(year + AC100_YEAR_OFF + 1900))
435		reg[6] |= AC100_RTC_YEA_LEAP;
436
437	return regmap_bulk_write(regmap, AC100_RTC_SEC, reg, 8);
438}
439
440static int ac100_rtc_alarm_irq_enable(struct device *dev, unsigned int en)
441{
442	struct ac100_rtc_dev *chip = dev_get_drvdata(dev);
443	struct regmap *regmap = chip->regmap;
444	unsigned int val;
445
446	val = en ? AC100_ALM_INT_ENABLE : 0;
447
448	return regmap_write(regmap, AC100_ALM_INT_ENA, val);
449}
450
451static int ac100_rtc_get_alarm(struct device *dev, struct rtc_wkalrm *alrm)
452{
453	struct ac100_rtc_dev *chip = dev_get_drvdata(dev);
454	struct regmap *regmap = chip->regmap;
455	struct rtc_time *alrm_tm = &alrm->time;
456	u16 reg[7];
457	unsigned int val;
458	int ret;
459
460	ret = regmap_read(regmap, AC100_ALM_INT_ENA, &val);
461	if (ret)
462		return ret;
463
464	alrm->enabled = !!(val & AC100_ALM_INT_ENABLE);
465
466	ret = regmap_bulk_read(regmap, AC100_ALM_SEC, reg, 7);
467	if (ret)
468		return ret;
469
470	alrm_tm->tm_sec  = bcd2bin(reg[0] & AC100_ALM_SEC_MASK);
471	alrm_tm->tm_min  = bcd2bin(reg[1] & AC100_ALM_MIN_MASK);
472	alrm_tm->tm_hour = bcd2bin(reg[2] & AC100_ALM_HOU_MASK);
473	alrm_tm->tm_wday = bcd2bin(reg[3] & AC100_ALM_WEE_MASK);
474	alrm_tm->tm_mday = bcd2bin(reg[4] & AC100_ALM_DAY_MASK);
475	alrm_tm->tm_mon  = bcd2bin(reg[5] & AC100_ALM_MON_MASK) - 1;
476	alrm_tm->tm_year = bcd2bin(reg[6] & AC100_ALM_YEA_MASK) +
477			   AC100_YEAR_OFF;
478
479	return 0;
480}
481
482static int ac100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
483{
484	struct ac100_rtc_dev *chip = dev_get_drvdata(dev);
485	struct regmap *regmap = chip->regmap;
486	struct rtc_time *alrm_tm = &alrm->time;
487	u16 reg[8];
488	int year;
489	int ret;
490
491	/* our alarm has a limited year range... */
492	year = alrm_tm->tm_year - AC100_YEAR_OFF;
493	if (year < 0 || year > (AC100_YEAR_MAX - 1900)) {
494		dev_err(dev, "alarm only supports year in range %d - %d\n",
495			AC100_YEAR_MIN, AC100_YEAR_MAX);
496		return -EINVAL;
497	}
498
499	/* convert to BCD */
500	reg[0] = (bin2bcd(alrm_tm->tm_sec)  & AC100_ALM_SEC_MASK) |
501			AC100_ALM_ENABLE_FLAG;
502	reg[1] = (bin2bcd(alrm_tm->tm_min)  & AC100_ALM_MIN_MASK) |
503			AC100_ALM_ENABLE_FLAG;
504	reg[2] = (bin2bcd(alrm_tm->tm_hour) & AC100_ALM_HOU_MASK) |
505			AC100_ALM_ENABLE_FLAG;
506	/* Do not enable weekday alarm */
507	reg[3] = bin2bcd(alrm_tm->tm_wday) & AC100_ALM_WEE_MASK;
508	reg[4] = (bin2bcd(alrm_tm->tm_mday) & AC100_ALM_DAY_MASK) |
509			AC100_ALM_ENABLE_FLAG;
510	reg[5] = (bin2bcd(alrm_tm->tm_mon + 1)  & AC100_ALM_MON_MASK) |
511			AC100_ALM_ENABLE_FLAG;
512	reg[6] = (bin2bcd(year) & AC100_ALM_YEA_MASK) |
513			AC100_ALM_ENABLE_FLAG;
514	/* trigger write */
515	reg[7] = AC100_ALM_UPD_TRIGGER;
516
517	ret = regmap_bulk_write(regmap, AC100_ALM_SEC, reg, 8);
518	if (ret)
519		return ret;
520
521	return ac100_rtc_alarm_irq_enable(dev, alrm->enabled);
522}
523
524static irqreturn_t ac100_rtc_irq(int irq, void *data)
525{
526	struct ac100_rtc_dev *chip = data;
527	struct regmap *regmap = chip->regmap;
528	unsigned int val = 0;
529	int ret;
530
531	rtc_lock(chip->rtc);
532
533	/* read status */
534	ret = regmap_read(regmap, AC100_ALM_INT_STA, &val);
535	if (ret)
536		goto out;
537
538	if (val & AC100_ALM_INT_ENABLE) {
539		/* signal rtc framework */
540		rtc_update_irq(chip->rtc, 1, RTC_AF | RTC_IRQF);
541
542		/* clear status */
543		ret = regmap_write(regmap, AC100_ALM_INT_STA, val);
544		if (ret)
545			goto out;
546
547		/* disable interrupt */
548		ret = ac100_rtc_alarm_irq_enable(chip->dev, 0);
549		if (ret)
550			goto out;
551	}
552
553out:
554	rtc_unlock(chip->rtc);
555	return IRQ_HANDLED;
556}
557
558static const struct rtc_class_ops ac100_rtc_ops = {
559	.read_time	  = ac100_rtc_get_time,
560	.set_time	  = ac100_rtc_set_time,
561	.read_alarm	  = ac100_rtc_get_alarm,
562	.set_alarm	  = ac100_rtc_set_alarm,
563	.alarm_irq_enable = ac100_rtc_alarm_irq_enable,
564};
565
566static int ac100_rtc_probe(struct platform_device *pdev)
567{
568	struct ac100_dev *ac100 = dev_get_drvdata(pdev->dev.parent);
569	struct ac100_rtc_dev *chip;
570	int ret;
571
572	chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
573	if (!chip)
574		return -ENOMEM;
575
576	platform_set_drvdata(pdev, chip);
577	chip->dev = &pdev->dev;
578	chip->regmap = ac100->regmap;
579
580	chip->irq = platform_get_irq(pdev, 0);
581	if (chip->irq < 0)
582		return chip->irq;
583
584	chip->rtc = devm_rtc_allocate_device(&pdev->dev);
585	if (IS_ERR(chip->rtc))
586		return PTR_ERR(chip->rtc);
587
588	chip->rtc->ops = &ac100_rtc_ops;
589
590	ret = devm_request_threaded_irq(&pdev->dev, chip->irq, NULL,
591					ac100_rtc_irq,
592					IRQF_SHARED | IRQF_ONESHOT,
593					dev_name(&pdev->dev), chip);
594	if (ret) {
595		dev_err(&pdev->dev, "Could not request IRQ\n");
596		return ret;
597	}
598
599	/* always use 24 hour mode */
600	regmap_write_bits(chip->regmap, AC100_RTC_CTRL, AC100_RTC_CTRL_24HOUR,
601			  AC100_RTC_CTRL_24HOUR);
602
603	/* disable counter alarm interrupt */
604	regmap_write(chip->regmap, AC100_ALM_INT_ENA, 0);
605
606	/* clear counter alarm pending interrupts */
607	regmap_write(chip->regmap, AC100_ALM_INT_STA, AC100_ALM_INT_ENABLE);
608
609	ret = ac100_rtc_register_clks(chip);
610	if (ret)
611		return ret;
612
613	return devm_rtc_register_device(chip->rtc);
614}
615
616static void ac100_rtc_remove(struct platform_device *pdev)
617{
618	struct ac100_rtc_dev *chip = platform_get_drvdata(pdev);
619
620	ac100_rtc_unregister_clks(chip);
621}
622
623static const struct of_device_id ac100_rtc_match[] = {
624	{ .compatible = "x-powers,ac100-rtc" },
625	{ },
626};
627MODULE_DEVICE_TABLE(of, ac100_rtc_match);
628
629static struct platform_driver ac100_rtc_driver = {
630	.probe		= ac100_rtc_probe,
631	.remove_new	= ac100_rtc_remove,
632	.driver		= {
633		.name		= "ac100-rtc",
634		.of_match_table	= of_match_ptr(ac100_rtc_match),
635	},
636};
637module_platform_driver(ac100_rtc_driver);
638
639MODULE_DESCRIPTION("X-Powers AC100 RTC driver");
640MODULE_AUTHOR("Chen-Yu Tsai <wens@csie.org>");
641MODULE_LICENSE("GPL v2");
642