xref: /linux/drivers/rtc/rtc-ac100.c (revision 23b0f90ba871f096474e1c27c3d14f455189d2d9)
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 
72 struct 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 
84 static const char * const ac100_clkout_names[AC100_CLKOUT_NUM] = {
85 	"ac100-cko1-rtc",
86 	"ac100-cko2-rtc",
87 	"ac100-cko3-rtc",
88 };
89 
90 struct 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 
106 static 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 */
119 static 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 
143 static int ac100_clkout_determine_rate(struct clk_hw *hw,
144 				       struct clk_rate_request *req)
145 {
146 	int i, ret, num_parents = clk_hw_get_num_parents(hw);
147 	struct clk_hw *best_parent = NULL;
148 	unsigned long best = 0;
149 
150 	for (i = 0; i < num_parents; i++) {
151 		struct clk_hw *parent = clk_hw_get_parent_by_index(hw, i);
152 		unsigned long prate;
153 
154 		/*
155 		 * The clock has two parents, one is a fixed clock which is
156 		 * internally registered by the ac100 driver. The other parent
157 		 * is a clock from the codec side of the chip, which we
158 		 * properly declare and reference in the devicetree and is
159 		 * not implemented in any driver right now.
160 		 * If the clock core looks for the parent of that second
161 		 * missing clock, it can't find one that is registered and
162 		 * returns NULL.
163 		 * So we end up in a situation where clk_hw_get_num_parents
164 		 * returns the amount of clocks we can be parented to, but
165 		 * clk_hw_get_parent_by_index will not return the orphan
166 		 * clocks.
167 		 * Thus we need to check if the parent exists before
168 		 * we get the parent rate, so we could use the RTC
169 		 * without waiting for the codec to be supported.
170 		 */
171 		if (!parent)
172 			continue;
173 
174 		prate = clk_hw_get_rate(parent);
175 
176 		if (prate == AC100_RTC_32K_RATE) {
177 			struct clk_rate_request div_req = *req;
178 
179 			div_req.best_parent_rate = prate;
180 
181 			ret = divider_determine_rate(hw, &div_req, NULL,
182 						     AC100_CLKOUT_DIV_WIDTH,
183 						     CLK_DIVIDER_POWER_OF_TWO);
184 			if (ret != 0 || div_req.rate > req->rate) {
185 				continue;
186 			} else if (req->rate - div_req.rate < req->rate - best) {
187 				best = div_req.rate;
188 				best_parent = parent;
189 			}
190 		} else {
191 			int j;
192 
193 			for (j = 0; ac100_clkout_prediv[j].div; j++) {
194 				struct clk_rate_request div_req = *req;
195 				unsigned long tmp_prate;
196 
197 				tmp_prate = DIV_ROUND_UP(prate, ac100_clkout_prediv[j].div);
198 				div_req.best_parent_rate = tmp_prate;
199 
200 				ret = divider_determine_rate(hw, &div_req, NULL,
201 							     AC100_CLKOUT_DIV_WIDTH,
202 							     CLK_DIVIDER_POWER_OF_TWO);
203 				if (ret != 0 || div_req.rate > req->rate) {
204 					continue;
205 				} else if (req->rate - div_req.rate < req->rate - best) {
206 					best = div_req.rate;
207 					best_parent = parent;
208 				}
209 			}
210 		}
211 	}
212 
213 	if (!best)
214 		return -EINVAL;
215 
216 	req->best_parent_hw = best_parent;
217 	req->best_parent_rate = clk_hw_get_rate(best_parent);
218 	req->rate = best;
219 
220 	return 0;
221 }
222 
223 static int ac100_clkout_set_rate(struct clk_hw *hw, unsigned long rate,
224 				 unsigned long prate)
225 {
226 	struct ac100_clkout *clk = to_ac100_clkout(hw);
227 	int div = 0, pre_div = 0;
228 
229 	do {
230 		div = divider_get_val(rate * ac100_clkout_prediv[pre_div].div,
231 				      prate, NULL, AC100_CLKOUT_DIV_WIDTH,
232 				      CLK_DIVIDER_POWER_OF_TWO);
233 		if (div >= 0)
234 			break;
235 	} while (prate != AC100_RTC_32K_RATE &&
236 		 ac100_clkout_prediv[++pre_div].div);
237 
238 	if (div < 0)
239 		return div;
240 
241 	pre_div = ac100_clkout_prediv[pre_div].val;
242 
243 	regmap_update_bits(clk->regmap, clk->offset,
244 			   ((1 << AC100_CLKOUT_DIV_WIDTH) - 1) << AC100_CLKOUT_DIV_SHIFT |
245 			   ((1 << AC100_CLKOUT_PRE_DIV_WIDTH) - 1) << AC100_CLKOUT_PRE_DIV_SHIFT,
246 			   (div - 1) << AC100_CLKOUT_DIV_SHIFT |
247 			   (pre_div - 1) << AC100_CLKOUT_PRE_DIV_SHIFT);
248 
249 	return 0;
250 }
251 
252 static int ac100_clkout_prepare(struct clk_hw *hw)
253 {
254 	struct ac100_clkout *clk = to_ac100_clkout(hw);
255 
256 	return regmap_update_bits(clk->regmap, clk->offset, AC100_CLKOUT_EN,
257 				  AC100_CLKOUT_EN);
258 }
259 
260 static void ac100_clkout_unprepare(struct clk_hw *hw)
261 {
262 	struct ac100_clkout *clk = to_ac100_clkout(hw);
263 
264 	regmap_update_bits(clk->regmap, clk->offset, AC100_CLKOUT_EN, 0);
265 }
266 
267 static int ac100_clkout_is_prepared(struct clk_hw *hw)
268 {
269 	struct ac100_clkout *clk = to_ac100_clkout(hw);
270 	unsigned int reg;
271 
272 	regmap_read(clk->regmap, clk->offset, &reg);
273 
274 	return reg & AC100_CLKOUT_EN;
275 }
276 
277 static u8 ac100_clkout_get_parent(struct clk_hw *hw)
278 {
279 	struct ac100_clkout *clk = to_ac100_clkout(hw);
280 	unsigned int reg;
281 
282 	regmap_read(clk->regmap, clk->offset, &reg);
283 
284 	return (reg >> AC100_CLKOUT_MUX_SHIFT) & 0x1;
285 }
286 
287 static int ac100_clkout_set_parent(struct clk_hw *hw, u8 index)
288 {
289 	struct ac100_clkout *clk = to_ac100_clkout(hw);
290 
291 	return regmap_update_bits(clk->regmap, clk->offset,
292 				  BIT(AC100_CLKOUT_MUX_SHIFT),
293 				  index ? BIT(AC100_CLKOUT_MUX_SHIFT) : 0);
294 }
295 
296 static const struct clk_ops ac100_clkout_ops = {
297 	.prepare	= ac100_clkout_prepare,
298 	.unprepare	= ac100_clkout_unprepare,
299 	.is_prepared	= ac100_clkout_is_prepared,
300 	.recalc_rate	= ac100_clkout_recalc_rate,
301 	.determine_rate	= ac100_clkout_determine_rate,
302 	.get_parent	= ac100_clkout_get_parent,
303 	.set_parent	= ac100_clkout_set_parent,
304 	.set_rate	= ac100_clkout_set_rate,
305 };
306 
307 static int ac100_rtc_register_clks(struct ac100_rtc_dev *chip)
308 {
309 	struct device_node *np = chip->dev->of_node;
310 	const char *parents[2] = {AC100_RTC_32K_NAME};
311 	int i, ret;
312 
313 	chip->clk_data = devm_kzalloc(chip->dev,
314 				      struct_size(chip->clk_data, hws,
315 						  AC100_CLKOUT_NUM),
316 				      GFP_KERNEL);
317 	if (!chip->clk_data)
318 		return -ENOMEM;
319 
320 	chip->rtc_32k_clk = clk_hw_register_fixed_rate(chip->dev,
321 						       AC100_RTC_32K_NAME,
322 						       NULL, 0,
323 						       AC100_RTC_32K_RATE);
324 	if (IS_ERR(chip->rtc_32k_clk)) {
325 		ret = PTR_ERR(chip->rtc_32k_clk);
326 		dev_err(chip->dev, "Failed to register RTC-32k clock: %d\n",
327 			ret);
328 		return ret;
329 	}
330 
331 	parents[1] = of_clk_get_parent_name(np, 0);
332 	if (!parents[1]) {
333 		dev_err(chip->dev, "Failed to get ADDA 4M clock\n");
334 		return -EINVAL;
335 	}
336 
337 	for (i = 0; i < AC100_CLKOUT_NUM; i++) {
338 		struct ac100_clkout *clk = &chip->clks[i];
339 		struct clk_init_data init = {
340 			.name = ac100_clkout_names[i],
341 			.ops = &ac100_clkout_ops,
342 			.parent_names = parents,
343 			.num_parents = ARRAY_SIZE(parents),
344 			.flags = 0,
345 		};
346 
347 		of_property_read_string_index(np, "clock-output-names",
348 					      i, &init.name);
349 		clk->regmap = chip->regmap;
350 		clk->offset = AC100_CLKOUT_CTRL1 + i;
351 		clk->hw.init = &init;
352 
353 		ret = devm_clk_hw_register(chip->dev, &clk->hw);
354 		if (ret) {
355 			dev_err(chip->dev, "Failed to register clk '%s': %d\n",
356 				init.name, ret);
357 			goto err_unregister_rtc_32k;
358 		}
359 
360 		chip->clk_data->hws[i] = &clk->hw;
361 	}
362 
363 	chip->clk_data->num = i;
364 	ret = of_clk_add_hw_provider(np, of_clk_hw_onecell_get, chip->clk_data);
365 	if (ret)
366 		goto err_unregister_rtc_32k;
367 
368 	return 0;
369 
370 err_unregister_rtc_32k:
371 	clk_unregister_fixed_rate(chip->rtc_32k_clk->clk);
372 
373 	return ret;
374 }
375 
376 static void ac100_rtc_unregister_clks(struct ac100_rtc_dev *chip)
377 {
378 	of_clk_del_provider(chip->dev->of_node);
379 	clk_unregister_fixed_rate(chip->rtc_32k_clk->clk);
380 }
381 
382 /*
383  * RTC related bits
384  */
385 static int ac100_rtc_get_time(struct device *dev, struct rtc_time *rtc_tm)
386 {
387 	struct ac100_rtc_dev *chip = dev_get_drvdata(dev);
388 	struct regmap *regmap = chip->regmap;
389 	u16 reg[7];
390 	int ret;
391 
392 	ret = regmap_bulk_read(regmap, AC100_RTC_SEC, reg, 7);
393 	if (ret)
394 		return ret;
395 
396 	rtc_tm->tm_sec  = bcd2bin(reg[0] & AC100_RTC_SEC_MASK);
397 	rtc_tm->tm_min  = bcd2bin(reg[1] & AC100_RTC_MIN_MASK);
398 	rtc_tm->tm_hour = bcd2bin(reg[2] & AC100_RTC_HOU_MASK);
399 	rtc_tm->tm_wday = bcd2bin(reg[3] & AC100_RTC_WEE_MASK);
400 	rtc_tm->tm_mday = bcd2bin(reg[4] & AC100_RTC_DAY_MASK);
401 	rtc_tm->tm_mon  = bcd2bin(reg[5] & AC100_RTC_MON_MASK) - 1;
402 	rtc_tm->tm_year = bcd2bin(reg[6] & AC100_RTC_YEA_MASK) +
403 			  AC100_YEAR_OFF;
404 
405 	return 0;
406 }
407 
408 static int ac100_rtc_set_time(struct device *dev, struct rtc_time *rtc_tm)
409 {
410 	struct ac100_rtc_dev *chip = dev_get_drvdata(dev);
411 	struct regmap *regmap = chip->regmap;
412 	int year;
413 	u16 reg[8];
414 
415 	/* our RTC has a limited year range... */
416 	year = rtc_tm->tm_year - AC100_YEAR_OFF;
417 	if (year < 0 || year > (AC100_YEAR_MAX - 1900)) {
418 		dev_err(dev, "rtc only supports year in range %d - %d\n",
419 			AC100_YEAR_MIN, AC100_YEAR_MAX);
420 		return -EINVAL;
421 	}
422 
423 	/* convert to BCD */
424 	reg[0] = bin2bcd(rtc_tm->tm_sec)     & AC100_RTC_SEC_MASK;
425 	reg[1] = bin2bcd(rtc_tm->tm_min)     & AC100_RTC_MIN_MASK;
426 	reg[2] = bin2bcd(rtc_tm->tm_hour)    & AC100_RTC_HOU_MASK;
427 	reg[3] = bin2bcd(rtc_tm->tm_wday)    & AC100_RTC_WEE_MASK;
428 	reg[4] = bin2bcd(rtc_tm->tm_mday)    & AC100_RTC_DAY_MASK;
429 	reg[5] = bin2bcd(rtc_tm->tm_mon + 1) & AC100_RTC_MON_MASK;
430 	reg[6] = bin2bcd(year)		     & AC100_RTC_YEA_MASK;
431 	/* trigger write */
432 	reg[7] = AC100_RTC_UPD_TRIGGER;
433 
434 	/* Is it a leap year? */
435 	if (is_leap_year(year + AC100_YEAR_OFF + 1900))
436 		reg[6] |= AC100_RTC_YEA_LEAP;
437 
438 	return regmap_bulk_write(regmap, AC100_RTC_SEC, reg, 8);
439 }
440 
441 static int ac100_rtc_alarm_irq_enable(struct device *dev, unsigned int en)
442 {
443 	struct ac100_rtc_dev *chip = dev_get_drvdata(dev);
444 	struct regmap *regmap = chip->regmap;
445 	unsigned int val;
446 
447 	val = en ? AC100_ALM_INT_ENABLE : 0;
448 
449 	return regmap_write(regmap, AC100_ALM_INT_ENA, val);
450 }
451 
452 static int ac100_rtc_get_alarm(struct device *dev, struct rtc_wkalrm *alrm)
453 {
454 	struct ac100_rtc_dev *chip = dev_get_drvdata(dev);
455 	struct regmap *regmap = chip->regmap;
456 	struct rtc_time *alrm_tm = &alrm->time;
457 	u16 reg[7];
458 	unsigned int val;
459 	int ret;
460 
461 	ret = regmap_read(regmap, AC100_ALM_INT_ENA, &val);
462 	if (ret)
463 		return ret;
464 
465 	alrm->enabled = !!(val & AC100_ALM_INT_ENABLE);
466 
467 	ret = regmap_bulk_read(regmap, AC100_ALM_SEC, reg, 7);
468 	if (ret)
469 		return ret;
470 
471 	alrm_tm->tm_sec  = bcd2bin(reg[0] & AC100_ALM_SEC_MASK);
472 	alrm_tm->tm_min  = bcd2bin(reg[1] & AC100_ALM_MIN_MASK);
473 	alrm_tm->tm_hour = bcd2bin(reg[2] & AC100_ALM_HOU_MASK);
474 	alrm_tm->tm_wday = bcd2bin(reg[3] & AC100_ALM_WEE_MASK);
475 	alrm_tm->tm_mday = bcd2bin(reg[4] & AC100_ALM_DAY_MASK);
476 	alrm_tm->tm_mon  = bcd2bin(reg[5] & AC100_ALM_MON_MASK) - 1;
477 	alrm_tm->tm_year = bcd2bin(reg[6] & AC100_ALM_YEA_MASK) +
478 			   AC100_YEAR_OFF;
479 
480 	return 0;
481 }
482 
483 static int ac100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
484 {
485 	struct ac100_rtc_dev *chip = dev_get_drvdata(dev);
486 	struct regmap *regmap = chip->regmap;
487 	struct rtc_time *alrm_tm = &alrm->time;
488 	u16 reg[8];
489 	int year;
490 	int ret;
491 
492 	/* our alarm has a limited year range... */
493 	year = alrm_tm->tm_year - AC100_YEAR_OFF;
494 	if (year < 0 || year > (AC100_YEAR_MAX - 1900)) {
495 		dev_err(dev, "alarm only supports year in range %d - %d\n",
496 			AC100_YEAR_MIN, AC100_YEAR_MAX);
497 		return -EINVAL;
498 	}
499 
500 	/* convert to BCD */
501 	reg[0] = (bin2bcd(alrm_tm->tm_sec)  & AC100_ALM_SEC_MASK) |
502 			AC100_ALM_ENABLE_FLAG;
503 	reg[1] = (bin2bcd(alrm_tm->tm_min)  & AC100_ALM_MIN_MASK) |
504 			AC100_ALM_ENABLE_FLAG;
505 	reg[2] = (bin2bcd(alrm_tm->tm_hour) & AC100_ALM_HOU_MASK) |
506 			AC100_ALM_ENABLE_FLAG;
507 	/* Do not enable weekday alarm */
508 	reg[3] = bin2bcd(alrm_tm->tm_wday) & AC100_ALM_WEE_MASK;
509 	reg[4] = (bin2bcd(alrm_tm->tm_mday) & AC100_ALM_DAY_MASK) |
510 			AC100_ALM_ENABLE_FLAG;
511 	reg[5] = (bin2bcd(alrm_tm->tm_mon + 1)  & AC100_ALM_MON_MASK) |
512 			AC100_ALM_ENABLE_FLAG;
513 	reg[6] = (bin2bcd(year) & AC100_ALM_YEA_MASK) |
514 			AC100_ALM_ENABLE_FLAG;
515 	/* trigger write */
516 	reg[7] = AC100_ALM_UPD_TRIGGER;
517 
518 	ret = regmap_bulk_write(regmap, AC100_ALM_SEC, reg, 8);
519 	if (ret)
520 		return ret;
521 
522 	return ac100_rtc_alarm_irq_enable(dev, alrm->enabled);
523 }
524 
525 static irqreturn_t ac100_rtc_irq(int irq, void *data)
526 {
527 	struct ac100_rtc_dev *chip = data;
528 	struct regmap *regmap = chip->regmap;
529 	unsigned int val = 0;
530 	int ret;
531 
532 	rtc_lock(chip->rtc);
533 
534 	/* read status */
535 	ret = regmap_read(regmap, AC100_ALM_INT_STA, &val);
536 	if (ret)
537 		goto out;
538 
539 	if (val & AC100_ALM_INT_ENABLE) {
540 		/* signal rtc framework */
541 		rtc_update_irq(chip->rtc, 1, RTC_AF | RTC_IRQF);
542 
543 		/* clear status */
544 		ret = regmap_write(regmap, AC100_ALM_INT_STA, val);
545 		if (ret)
546 			goto out;
547 
548 		/* disable interrupt */
549 		ret = ac100_rtc_alarm_irq_enable(chip->dev, 0);
550 		if (ret)
551 			goto out;
552 	}
553 
554 out:
555 	rtc_unlock(chip->rtc);
556 	return IRQ_HANDLED;
557 }
558 
559 static const struct rtc_class_ops ac100_rtc_ops = {
560 	.read_time	  = ac100_rtc_get_time,
561 	.set_time	  = ac100_rtc_set_time,
562 	.read_alarm	  = ac100_rtc_get_alarm,
563 	.set_alarm	  = ac100_rtc_set_alarm,
564 	.alarm_irq_enable = ac100_rtc_alarm_irq_enable,
565 };
566 
567 static int ac100_rtc_probe(struct platform_device *pdev)
568 {
569 	struct ac100_dev *ac100 = dev_get_drvdata(pdev->dev.parent);
570 	struct ac100_rtc_dev *chip;
571 	int ret;
572 
573 	chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
574 	if (!chip)
575 		return -ENOMEM;
576 
577 	platform_set_drvdata(pdev, chip);
578 	chip->dev = &pdev->dev;
579 	chip->regmap = ac100->regmap;
580 
581 	chip->irq = platform_get_irq(pdev, 0);
582 	if (chip->irq < 0)
583 		return chip->irq;
584 
585 	chip->rtc = devm_rtc_allocate_device(&pdev->dev);
586 	if (IS_ERR(chip->rtc))
587 		return PTR_ERR(chip->rtc);
588 
589 	chip->rtc->ops = &ac100_rtc_ops;
590 
591 	ret = devm_request_threaded_irq(&pdev->dev, chip->irq, NULL,
592 					ac100_rtc_irq,
593 					IRQF_SHARED | IRQF_ONESHOT,
594 					dev_name(&pdev->dev), chip);
595 	if (ret) {
596 		dev_err(&pdev->dev, "Could not request IRQ\n");
597 		return ret;
598 	}
599 
600 	/* always use 24 hour mode */
601 	regmap_write_bits(chip->regmap, AC100_RTC_CTRL, AC100_RTC_CTRL_24HOUR,
602 			  AC100_RTC_CTRL_24HOUR);
603 
604 	/* disable counter alarm interrupt */
605 	regmap_write(chip->regmap, AC100_ALM_INT_ENA, 0);
606 
607 	/* clear counter alarm pending interrupts */
608 	regmap_write(chip->regmap, AC100_ALM_INT_STA, AC100_ALM_INT_ENABLE);
609 
610 	ret = ac100_rtc_register_clks(chip);
611 	if (ret)
612 		return ret;
613 
614 	return devm_rtc_register_device(chip->rtc);
615 }
616 
617 static void ac100_rtc_remove(struct platform_device *pdev)
618 {
619 	struct ac100_rtc_dev *chip = platform_get_drvdata(pdev);
620 
621 	ac100_rtc_unregister_clks(chip);
622 }
623 
624 static const struct of_device_id ac100_rtc_match[] = {
625 	{ .compatible = "x-powers,ac100-rtc" },
626 	{ },
627 };
628 MODULE_DEVICE_TABLE(of, ac100_rtc_match);
629 
630 static struct platform_driver ac100_rtc_driver = {
631 	.probe		= ac100_rtc_probe,
632 	.remove		= ac100_rtc_remove,
633 	.driver		= {
634 		.name		= "ac100-rtc",
635 		.of_match_table	= of_match_ptr(ac100_rtc_match),
636 	},
637 };
638 module_platform_driver(ac100_rtc_driver);
639 
640 MODULE_DESCRIPTION("X-Powers AC100 RTC driver");
641 MODULE_AUTHOR("Chen-Yu Tsai <wens@csie.org>");
642 MODULE_LICENSE("GPL v2");
643