xref: /linux/drivers/rtc/rtc-nct3018y.c (revision 0074281bb6316108e0cff094bd4db78ab3eee236)
1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (c) 2022 Nuvoton Technology Corporation
3 
4 #include <linux/bcd.h>
5 #include <linux/clk-provider.h>
6 #include <linux/err.h>
7 #include <linux/i2c.h>
8 #include <linux/module.h>
9 #include <linux/of.h>
10 #include <linux/rtc.h>
11 #include <linux/slab.h>
12 
13 #define NCT3018Y_REG_SC		0x00 /* seconds */
14 #define NCT3018Y_REG_SCA	0x01 /* alarm */
15 #define NCT3018Y_REG_MN		0x02
16 #define NCT3018Y_REG_MNA	0x03 /* alarm */
17 #define NCT3018Y_REG_HR		0x04
18 #define NCT3018Y_REG_HRA	0x05 /* alarm */
19 #define NCT3018Y_REG_DW		0x06
20 #define NCT3018Y_REG_DM		0x07
21 #define NCT3018Y_REG_MO		0x08
22 #define NCT3018Y_REG_YR		0x09
23 #define NCT3018Y_REG_CTRL	0x0A /* timer control */
24 #define NCT3018Y_REG_ST		0x0B /* status */
25 #define NCT3018Y_REG_CLKO	0x0C /* clock out */
26 #define NCT3018Y_REG_PART	0x21 /* part info */
27 
28 #define NCT3018Y_BIT_AF		BIT(7)
29 #define NCT3018Y_BIT_ST		BIT(7)
30 #define NCT3018Y_BIT_DM		BIT(6)
31 #define NCT3018Y_BIT_HF		BIT(5)
32 #define NCT3018Y_BIT_DSM	BIT(4)
33 #define NCT3018Y_BIT_AIE	BIT(3)
34 #define NCT3018Y_BIT_OFIE	BIT(2)
35 #define NCT3018Y_BIT_CIE	BIT(1)
36 #define NCT3018Y_BIT_TWO	BIT(0)
37 
38 #define NCT3018Y_REG_BAT_MASK		0x07
39 #define NCT3018Y_REG_CLKO_F_MASK	0x03 /* frequenc mask */
40 #define NCT3018Y_REG_CLKO_CKE		0x80 /* clock out enabled */
41 #define NCT3018Y_REG_PART_NCT3018Y	0x02
42 
43 struct nct3018y {
44 	struct rtc_device *rtc;
45 	struct i2c_client *client;
46 	int part_num;
47 #ifdef CONFIG_COMMON_CLK
48 	struct clk_hw clkout_hw;
49 #endif
50 };
51 
nct3018y_set_alarm_mode(struct i2c_client * client,bool on)52 static int nct3018y_set_alarm_mode(struct i2c_client *client, bool on)
53 {
54 	int err, flags;
55 
56 	dev_dbg(&client->dev, "%s:on:%d\n", __func__, on);
57 
58 	flags =  i2c_smbus_read_byte_data(client, NCT3018Y_REG_CTRL);
59 	if (flags < 0) {
60 		dev_dbg(&client->dev,
61 			"Failed to read NCT3018Y_REG_CTRL\n");
62 		return flags;
63 	}
64 
65 	if (on)
66 		flags |= NCT3018Y_BIT_AIE;
67 	else
68 		flags &= ~NCT3018Y_BIT_AIE;
69 
70 	flags |= NCT3018Y_BIT_CIE;
71 	err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_CTRL, flags);
72 	if (err < 0) {
73 		dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_CTRL\n");
74 		return err;
75 	}
76 
77 	flags =  i2c_smbus_read_byte_data(client, NCT3018Y_REG_ST);
78 	if (flags < 0) {
79 		dev_dbg(&client->dev,
80 			"Failed to read NCT3018Y_REG_ST\n");
81 		return flags;
82 	}
83 
84 	flags &= ~(NCT3018Y_BIT_AF);
85 	err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_ST, flags);
86 	if (err < 0) {
87 		dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_ST\n");
88 		return err;
89 	}
90 
91 	return 0;
92 }
93 
nct3018y_get_alarm_mode(struct i2c_client * client,unsigned char * alarm_enable,unsigned char * alarm_flag)94 static int nct3018y_get_alarm_mode(struct i2c_client *client, unsigned char *alarm_enable,
95 				   unsigned char *alarm_flag)
96 {
97 	int flags;
98 
99 	if (alarm_enable) {
100 		dev_dbg(&client->dev, "%s:NCT3018Y_REG_CTRL\n", __func__);
101 		flags =  i2c_smbus_read_byte_data(client, NCT3018Y_REG_CTRL);
102 		if (flags < 0)
103 			return flags;
104 		*alarm_enable = flags & NCT3018Y_BIT_AIE;
105 		dev_dbg(&client->dev, "%s:alarm_enable:%x\n", __func__, *alarm_enable);
106 
107 	}
108 
109 	if (alarm_flag) {
110 		dev_dbg(&client->dev, "%s:NCT3018Y_REG_ST\n", __func__);
111 		flags =  i2c_smbus_read_byte_data(client, NCT3018Y_REG_ST);
112 		if (flags < 0)
113 			return flags;
114 		*alarm_flag = flags & NCT3018Y_BIT_AF;
115 		dev_dbg(&client->dev, "%s:alarm_flag:%x\n", __func__, *alarm_flag);
116 	}
117 
118 	return 0;
119 }
120 
nct3018y_irq(int irq,void * dev_id)121 static irqreturn_t nct3018y_irq(int irq, void *dev_id)
122 {
123 	struct nct3018y *nct3018y = i2c_get_clientdata(dev_id);
124 	struct i2c_client *client = nct3018y->client;
125 	int err;
126 	unsigned char alarm_flag;
127 	unsigned char alarm_enable;
128 
129 	dev_dbg(&client->dev, "%s:irq:%d\n", __func__, irq);
130 	err = nct3018y_get_alarm_mode(nct3018y->client, &alarm_enable, &alarm_flag);
131 	if (err)
132 		return IRQ_NONE;
133 
134 	if (alarm_flag) {
135 		dev_dbg(&client->dev, "%s:alarm flag:%x\n",
136 			__func__, alarm_flag);
137 		rtc_update_irq(nct3018y->rtc, 1, RTC_IRQF | RTC_AF);
138 		nct3018y_set_alarm_mode(nct3018y->client, 0);
139 		dev_dbg(&client->dev, "%s:IRQ_HANDLED\n", __func__);
140 		return IRQ_HANDLED;
141 	}
142 
143 	return IRQ_NONE;
144 }
145 
146 /*
147  * In the routines that deal directly with the nct3018y hardware, we use
148  * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
149  */
nct3018y_rtc_read_time(struct device * dev,struct rtc_time * tm)150 static int nct3018y_rtc_read_time(struct device *dev, struct rtc_time *tm)
151 {
152 	struct i2c_client *client = to_i2c_client(dev);
153 	unsigned char buf[10];
154 	int err;
155 
156 	err = i2c_smbus_read_i2c_block_data(client, NCT3018Y_REG_ST, 1, buf);
157 	if (err < 0)
158 		return err;
159 
160 	if (!buf[0]) {
161 		dev_dbg(&client->dev, " voltage <=1.7, date/time is not reliable.\n");
162 		return -EINVAL;
163 	}
164 
165 	err = i2c_smbus_read_i2c_block_data(client, NCT3018Y_REG_SC, sizeof(buf), buf);
166 	if (err < 0)
167 		return err;
168 
169 	tm->tm_sec = bcd2bin(buf[0] & 0x7F);
170 	tm->tm_min = bcd2bin(buf[2] & 0x7F);
171 	tm->tm_hour = bcd2bin(buf[4] & 0x3F);
172 	tm->tm_wday = buf[6] & 0x07;
173 	tm->tm_mday = bcd2bin(buf[7] & 0x3F);
174 	tm->tm_mon = bcd2bin(buf[8] & 0x1F) - 1;
175 	tm->tm_year = bcd2bin(buf[9]) + 100;
176 
177 	return 0;
178 }
179 
nct3018y_rtc_set_time(struct device * dev,struct rtc_time * tm)180 static int nct3018y_rtc_set_time(struct device *dev, struct rtc_time *tm)
181 {
182 	struct i2c_client *client = to_i2c_client(dev);
183 	struct nct3018y *nct3018y = dev_get_drvdata(dev);
184 	unsigned char buf[4] = {0};
185 	int err, flags;
186 	int restore_flags = 0;
187 
188 	flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_CTRL);
189 	if (flags < 0) {
190 		dev_dbg(&client->dev, "Failed to read NCT3018Y_REG_CTRL.\n");
191 		return flags;
192 	}
193 
194 	/* Check and set TWO bit */
195 	if (nct3018y->part_num == NCT3018Y_REG_PART_NCT3018Y && !(flags & NCT3018Y_BIT_TWO)) {
196 		restore_flags = 1;
197 		flags |= NCT3018Y_BIT_TWO;
198 		err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_CTRL, flags);
199 		if (err < 0) {
200 			dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_CTRL.\n");
201 			return err;
202 		}
203 	}
204 
205 	buf[0] = bin2bcd(tm->tm_sec);
206 	err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_SC, buf[0]);
207 	if (err < 0) {
208 		dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_SC\n");
209 		return err;
210 	}
211 
212 	buf[0] = bin2bcd(tm->tm_min);
213 	err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_MN, buf[0]);
214 	if (err < 0) {
215 		dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_MN\n");
216 		return err;
217 	}
218 
219 	buf[0] = bin2bcd(tm->tm_hour);
220 	err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_HR, buf[0]);
221 	if (err < 0) {
222 		dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_HR\n");
223 		return err;
224 	}
225 
226 	buf[0] = tm->tm_wday & 0x07;
227 	buf[1] = bin2bcd(tm->tm_mday);
228 	buf[2] = bin2bcd(tm->tm_mon + 1);
229 	buf[3] = bin2bcd(tm->tm_year - 100);
230 	err = i2c_smbus_write_i2c_block_data(client, NCT3018Y_REG_DW,
231 					     sizeof(buf), buf);
232 	if (err < 0) {
233 		dev_dbg(&client->dev, "Unable to write for day and mon and year\n");
234 		return -EIO;
235 	}
236 
237 	/* Restore TWO bit */
238 	if (restore_flags) {
239 		if (nct3018y->part_num == NCT3018Y_REG_PART_NCT3018Y)
240 			flags &= ~NCT3018Y_BIT_TWO;
241 
242 		err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_CTRL, flags);
243 		if (err < 0) {
244 			dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_CTRL.\n");
245 			return err;
246 		}
247 	}
248 
249 	return err;
250 }
251 
nct3018y_rtc_read_alarm(struct device * dev,struct rtc_wkalrm * tm)252 static int nct3018y_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *tm)
253 {
254 	struct i2c_client *client = to_i2c_client(dev);
255 	unsigned char buf[5];
256 	int err;
257 
258 	err = i2c_smbus_read_i2c_block_data(client, NCT3018Y_REG_SCA,
259 					    sizeof(buf), buf);
260 	if (err < 0) {
261 		dev_dbg(&client->dev, "Unable to read date\n");
262 		return -EIO;
263 	}
264 
265 	dev_dbg(&client->dev, "%s: raw data is sec=%02x, min=%02x hr=%02x\n",
266 		__func__, buf[0], buf[2], buf[4]);
267 
268 	tm->time.tm_sec = bcd2bin(buf[0] & 0x7F);
269 	tm->time.tm_min = bcd2bin(buf[2] & 0x7F);
270 	tm->time.tm_hour = bcd2bin(buf[4] & 0x3F);
271 
272 	err = nct3018y_get_alarm_mode(client, &tm->enabled, &tm->pending);
273 	if (err < 0)
274 		return err;
275 
276 	dev_dbg(&client->dev, "%s:s=%d m=%d, hr=%d, enabled=%d, pending=%d\n",
277 		__func__, tm->time.tm_sec, tm->time.tm_min,
278 		tm->time.tm_hour, tm->enabled, tm->pending);
279 
280 	return 0;
281 }
282 
nct3018y_rtc_set_alarm(struct device * dev,struct rtc_wkalrm * tm)283 static int nct3018y_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *tm)
284 {
285 	struct i2c_client *client = to_i2c_client(dev);
286 	int err;
287 
288 	dev_dbg(dev, "%s, sec=%d, min=%d hour=%d tm->enabled:%d\n",
289 		__func__, tm->time.tm_sec, tm->time.tm_min, tm->time.tm_hour,
290 		tm->enabled);
291 
292 	err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_SCA, bin2bcd(tm->time.tm_sec));
293 	if (err < 0) {
294 		dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_SCA\n");
295 		return err;
296 	}
297 
298 	err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_MNA, bin2bcd(tm->time.tm_min));
299 	if (err < 0) {
300 		dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_MNA\n");
301 		return err;
302 	}
303 
304 	err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_HRA, bin2bcd(tm->time.tm_hour));
305 	if (err < 0) {
306 		dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_HRA\n");
307 		return err;
308 	}
309 
310 	return nct3018y_set_alarm_mode(client, tm->enabled);
311 }
312 
nct3018y_irq_enable(struct device * dev,unsigned int enabled)313 static int nct3018y_irq_enable(struct device *dev, unsigned int enabled)
314 {
315 	dev_dbg(dev, "%s: alarm enable=%d\n", __func__, enabled);
316 
317 	return nct3018y_set_alarm_mode(to_i2c_client(dev), enabled);
318 }
319 
nct3018y_ioctl(struct device * dev,unsigned int cmd,unsigned long arg)320 static int nct3018y_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
321 {
322 	struct i2c_client *client = to_i2c_client(dev);
323 	int status, flags = 0;
324 
325 	switch (cmd) {
326 	case RTC_VL_READ:
327 		status = i2c_smbus_read_byte_data(client, NCT3018Y_REG_ST);
328 		if (status < 0)
329 			return status;
330 
331 		if (!(status & NCT3018Y_REG_BAT_MASK))
332 			flags |= RTC_VL_DATA_INVALID;
333 
334 		return put_user(flags, (unsigned int __user *)arg);
335 
336 	default:
337 		return -ENOIOCTLCMD;
338 	}
339 }
340 
341 #ifdef CONFIG_COMMON_CLK
342 /*
343  * Handling of the clkout
344  */
345 
346 #define clkout_hw_to_nct3018y(_hw) container_of(_hw, struct nct3018y, clkout_hw)
347 
348 static const int clkout_rates[] = {
349 	32768,
350 	1024,
351 	32,
352 	1,
353 };
354 
nct3018y_clkout_recalc_rate(struct clk_hw * hw,unsigned long parent_rate)355 static unsigned long nct3018y_clkout_recalc_rate(struct clk_hw *hw,
356 						 unsigned long parent_rate)
357 {
358 	struct nct3018y *nct3018y = clkout_hw_to_nct3018y(hw);
359 	struct i2c_client *client = nct3018y->client;
360 	int flags;
361 
362 	flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_CLKO);
363 	if (flags < 0)
364 		return 0;
365 
366 	flags &= NCT3018Y_REG_CLKO_F_MASK;
367 	return clkout_rates[flags];
368 }
369 
nct3018y_clkout_determine_rate(struct clk_hw * hw,struct clk_rate_request * req)370 static int nct3018y_clkout_determine_rate(struct clk_hw *hw,
371 					  struct clk_rate_request *req)
372 {
373 	int i;
374 
375 	for (i = 0; i < ARRAY_SIZE(clkout_rates); i++)
376 		if (clkout_rates[i] <= req->rate) {
377 			req->rate = clkout_rates[i];
378 
379 			return 0;
380 		}
381 
382 	req->rate = clkout_rates[0];
383 
384 	return 0;
385 }
386 
nct3018y_clkout_set_rate(struct clk_hw * hw,unsigned long rate,unsigned long parent_rate)387 static int nct3018y_clkout_set_rate(struct clk_hw *hw, unsigned long rate,
388 				    unsigned long parent_rate)
389 {
390 	struct nct3018y *nct3018y = clkout_hw_to_nct3018y(hw);
391 	struct i2c_client *client = nct3018y->client;
392 	int i, flags;
393 
394 	flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_CLKO);
395 	if (flags < 0)
396 		return flags;
397 
398 	for (i = 0; i < ARRAY_SIZE(clkout_rates); i++)
399 		if (clkout_rates[i] == rate) {
400 			flags &= ~NCT3018Y_REG_CLKO_F_MASK;
401 			flags |= i;
402 			return i2c_smbus_write_byte_data(client, NCT3018Y_REG_CLKO, flags);
403 		}
404 
405 	return -EINVAL;
406 }
407 
nct3018y_clkout_control(struct clk_hw * hw,bool enable)408 static int nct3018y_clkout_control(struct clk_hw *hw, bool enable)
409 {
410 	struct nct3018y *nct3018y = clkout_hw_to_nct3018y(hw);
411 	struct i2c_client *client = nct3018y->client;
412 	int flags;
413 
414 	flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_CLKO);
415 	if (flags < 0)
416 		return flags;
417 
418 	if (enable)
419 		flags |= NCT3018Y_REG_CLKO_CKE;
420 	else
421 		flags &= ~NCT3018Y_REG_CLKO_CKE;
422 
423 	return i2c_smbus_write_byte_data(client, NCT3018Y_REG_CLKO, flags);
424 }
425 
nct3018y_clkout_prepare(struct clk_hw * hw)426 static int nct3018y_clkout_prepare(struct clk_hw *hw)
427 {
428 	return nct3018y_clkout_control(hw, 1);
429 }
430 
nct3018y_clkout_unprepare(struct clk_hw * hw)431 static void nct3018y_clkout_unprepare(struct clk_hw *hw)
432 {
433 	nct3018y_clkout_control(hw, 0);
434 }
435 
nct3018y_clkout_is_prepared(struct clk_hw * hw)436 static int nct3018y_clkout_is_prepared(struct clk_hw *hw)
437 {
438 	struct nct3018y *nct3018y = clkout_hw_to_nct3018y(hw);
439 	struct i2c_client *client = nct3018y->client;
440 	int flags;
441 
442 	flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_CLKO);
443 	if (flags < 0)
444 		return flags;
445 
446 	return flags & NCT3018Y_REG_CLKO_CKE;
447 }
448 
449 static const struct clk_ops nct3018y_clkout_ops = {
450 	.prepare = nct3018y_clkout_prepare,
451 	.unprepare = nct3018y_clkout_unprepare,
452 	.is_prepared = nct3018y_clkout_is_prepared,
453 	.recalc_rate = nct3018y_clkout_recalc_rate,
454 	.determine_rate = nct3018y_clkout_determine_rate,
455 	.set_rate = nct3018y_clkout_set_rate,
456 };
457 
nct3018y_clkout_register_clk(struct nct3018y * nct3018y)458 static struct clk *nct3018y_clkout_register_clk(struct nct3018y *nct3018y)
459 {
460 	struct i2c_client *client = nct3018y->client;
461 	struct device_node *node = client->dev.of_node;
462 	struct clk *clk;
463 	struct clk_init_data init;
464 
465 	init.name = "nct3018y-clkout";
466 	init.ops = &nct3018y_clkout_ops;
467 	init.flags = 0;
468 	init.parent_names = NULL;
469 	init.num_parents = 0;
470 	nct3018y->clkout_hw.init = &init;
471 
472 	/* optional override of the clockname */
473 	of_property_read_string(node, "clock-output-names", &init.name);
474 
475 	/* register the clock */
476 	clk = devm_clk_register(&client->dev, &nct3018y->clkout_hw);
477 
478 	if (!IS_ERR(clk))
479 		of_clk_add_provider(node, of_clk_src_simple_get, clk);
480 
481 	return clk;
482 }
483 #endif
484 
485 static const struct rtc_class_ops nct3018y_rtc_ops = {
486 	.read_time	= nct3018y_rtc_read_time,
487 	.set_time	= nct3018y_rtc_set_time,
488 	.read_alarm	= nct3018y_rtc_read_alarm,
489 	.set_alarm	= nct3018y_rtc_set_alarm,
490 	.alarm_irq_enable = nct3018y_irq_enable,
491 	.ioctl		= nct3018y_ioctl,
492 };
493 
nct3018y_probe(struct i2c_client * client)494 static int nct3018y_probe(struct i2c_client *client)
495 {
496 	struct nct3018y *nct3018y;
497 	int err, flags;
498 
499 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
500 				     I2C_FUNC_SMBUS_BYTE |
501 				     I2C_FUNC_SMBUS_BLOCK_DATA))
502 		return -ENODEV;
503 
504 	nct3018y = devm_kzalloc(&client->dev, sizeof(struct nct3018y),
505 				GFP_KERNEL);
506 	if (!nct3018y)
507 		return -ENOMEM;
508 
509 	i2c_set_clientdata(client, nct3018y);
510 	nct3018y->client = client;
511 	device_set_wakeup_capable(&client->dev, 1);
512 
513 	flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_CTRL);
514 	if (flags < 0) {
515 		dev_dbg(&client->dev, "%s: read error\n", __func__);
516 		return flags;
517 	} else if (flags & NCT3018Y_BIT_TWO) {
518 		dev_dbg(&client->dev, "%s: NCT3018Y_BIT_TWO is set\n", __func__);
519 	}
520 
521 	nct3018y->part_num = i2c_smbus_read_byte_data(client, NCT3018Y_REG_PART);
522 	if (nct3018y->part_num < 0) {
523 		dev_dbg(&client->dev, "Failed to read NCT3018Y_REG_PART.\n");
524 		return nct3018y->part_num;
525 	} else {
526 		nct3018y->part_num &= 0x03; /* Part number is corresponding to bit 0 and 1 */
527 		if (nct3018y->part_num == NCT3018Y_REG_PART_NCT3018Y) {
528 			flags = NCT3018Y_BIT_HF;
529 			err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_CTRL, flags);
530 			if (err < 0) {
531 				dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_CTRL.\n");
532 				return err;
533 			}
534 		}
535 	}
536 
537 	flags = 0;
538 	err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_ST, flags);
539 	if (err < 0) {
540 		dev_dbg(&client->dev, "%s: write error\n", __func__);
541 		return err;
542 	}
543 
544 	nct3018y->rtc = devm_rtc_allocate_device(&client->dev);
545 	if (IS_ERR(nct3018y->rtc))
546 		return PTR_ERR(nct3018y->rtc);
547 
548 	nct3018y->rtc->ops = &nct3018y_rtc_ops;
549 	nct3018y->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
550 	nct3018y->rtc->range_max = RTC_TIMESTAMP_END_2099;
551 
552 	if (client->irq > 0) {
553 		err = devm_request_threaded_irq(&client->dev, client->irq,
554 						NULL, nct3018y_irq,
555 						IRQF_ONESHOT | IRQF_TRIGGER_FALLING,
556 						"nct3018y", client);
557 		if (err) {
558 			dev_dbg(&client->dev, "unable to request IRQ %d\n", client->irq);
559 			return err;
560 		}
561 	} else {
562 		clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, nct3018y->rtc->features);
563 		clear_bit(RTC_FEATURE_ALARM, nct3018y->rtc->features);
564 	}
565 
566 #ifdef CONFIG_COMMON_CLK
567 	/* register clk in common clk framework */
568 	nct3018y_clkout_register_clk(nct3018y);
569 #endif
570 
571 	return devm_rtc_register_device(nct3018y->rtc);
572 }
573 
574 static const struct i2c_device_id nct3018y_id[] = {
575 	{ "nct3018y" },
576 	{ }
577 };
578 MODULE_DEVICE_TABLE(i2c, nct3018y_id);
579 
580 static const struct of_device_id nct3018y_of_match[] = {
581 	{ .compatible = "nuvoton,nct3018y" },
582 	{}
583 };
584 MODULE_DEVICE_TABLE(of, nct3018y_of_match);
585 
586 static struct i2c_driver nct3018y_driver = {
587 	.driver		= {
588 		.name	= "rtc-nct3018y",
589 		.of_match_table = nct3018y_of_match,
590 	},
591 	.probe		= nct3018y_probe,
592 	.id_table	= nct3018y_id,
593 };
594 
595 module_i2c_driver(nct3018y_driver);
596 
597 MODULE_AUTHOR("Medad CChien <ctcchien@nuvoton.com>");
598 MODULE_AUTHOR("Mia Lin <mimi05633@gmail.com>");
599 MODULE_DESCRIPTION("Nuvoton NCT3018Y RTC driver");
600 MODULE_LICENSE("GPL");
601