xref: /linux/drivers/rtc/rtc-rs5c372.c (revision 2fe05e1139a555ae91f00a812cb9520e7d3022ab)
1 /*
2  * An I2C driver for Ricoh RS5C372, R2025S/D and RV5C38[67] RTCs
3  *
4  * Copyright (C) 2005 Pavel Mironchik <pmironchik@optifacio.net>
5  * Copyright (C) 2006 Tower Technologies
6  * Copyright (C) 2008 Paul Mundt
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License version 2 as
10  * published by the Free Software Foundation.
11  */
12 
13 #include <linux/i2c.h>
14 #include <linux/rtc.h>
15 #include <linux/bcd.h>
16 #include <linux/slab.h>
17 #include <linux/module.h>
18 #include <linux/of_device.h>
19 
20 /*
21  * Ricoh has a family of I2C based RTCs, which differ only slightly from
22  * each other.  Differences center on pinout (e.g. how many interrupts,
23  * output clock, etc) and how the control registers are used.  The '372
24  * is significant only because that's the one this driver first supported.
25  */
26 #define RS5C372_REG_SECS	0
27 #define RS5C372_REG_MINS	1
28 #define RS5C372_REG_HOURS	2
29 #define RS5C372_REG_WDAY	3
30 #define RS5C372_REG_DAY		4
31 #define RS5C372_REG_MONTH	5
32 #define RS5C372_REG_YEAR	6
33 #define RS5C372_REG_TRIM	7
34 #	define RS5C372_TRIM_XSL		0x80
35 #	define RS5C372_TRIM_MASK	0x7F
36 
37 #define RS5C_REG_ALARM_A_MIN	8			/* or ALARM_W */
38 #define RS5C_REG_ALARM_A_HOURS	9
39 #define RS5C_REG_ALARM_A_WDAY	10
40 
41 #define RS5C_REG_ALARM_B_MIN	11			/* or ALARM_D */
42 #define RS5C_REG_ALARM_B_HOURS	12
43 #define RS5C_REG_ALARM_B_WDAY	13			/* (ALARM_B only) */
44 
45 #define RS5C_REG_CTRL1		14
46 #	define RS5C_CTRL1_AALE		(1 << 7)	/* or WALE */
47 #	define RS5C_CTRL1_BALE		(1 << 6)	/* or DALE */
48 #	define RV5C387_CTRL1_24		(1 << 5)
49 #	define RS5C372A_CTRL1_SL1	(1 << 5)
50 #	define RS5C_CTRL1_CT_MASK	(7 << 0)
51 #	define RS5C_CTRL1_CT0		(0 << 0)	/* no periodic irq */
52 #	define RS5C_CTRL1_CT4		(4 << 0)	/* 1 Hz level irq */
53 #define RS5C_REG_CTRL2		15
54 #	define RS5C372_CTRL2_24		(1 << 5)
55 #	define R2025_CTRL2_XST		(1 << 5)
56 #	define RS5C_CTRL2_XSTP		(1 << 4)	/* only if !R2025S/D */
57 #	define RS5C_CTRL2_CTFG		(1 << 2)
58 #	define RS5C_CTRL2_AAFG		(1 << 1)	/* or WAFG */
59 #	define RS5C_CTRL2_BAFG		(1 << 0)	/* or DAFG */
60 
61 
62 /* to read (style 1) or write registers starting at R */
63 #define RS5C_ADDR(R)		(((R) << 4) | 0)
64 
65 
66 enum rtc_type {
67 	rtc_undef = 0,
68 	rtc_r2025sd,
69 	rtc_r2221tl,
70 	rtc_rs5c372a,
71 	rtc_rs5c372b,
72 	rtc_rv5c386,
73 	rtc_rv5c387a,
74 };
75 
76 static const struct i2c_device_id rs5c372_id[] = {
77 	{ "r2025sd", rtc_r2025sd },
78 	{ "r2221tl", rtc_r2221tl },
79 	{ "rs5c372a", rtc_rs5c372a },
80 	{ "rs5c372b", rtc_rs5c372b },
81 	{ "rv5c386", rtc_rv5c386 },
82 	{ "rv5c387a", rtc_rv5c387a },
83 	{ }
84 };
85 MODULE_DEVICE_TABLE(i2c, rs5c372_id);
86 
87 static const struct of_device_id rs5c372_of_match[] = {
88 	{
89 		.compatible = "ricoh,r2025sd",
90 		.data = (void *)rtc_r2025sd
91 	},
92 	{
93 		.compatible = "ricoh,r2221tl",
94 		.data = (void *)rtc_r2221tl
95 	},
96 	{
97 		.compatible = "ricoh,rs5c372a",
98 		.data = (void *)rtc_rs5c372a
99 	},
100 	{
101 		.compatible = "ricoh,rs5c372b",
102 		.data = (void *)rtc_rs5c372b
103 	},
104 	{
105 		.compatible = "ricoh,rv5c386",
106 		.data = (void *)rtc_rv5c386
107 	},
108 	{
109 		.compatible = "ricoh,rv5c387a",
110 		.data = (void *)rtc_rv5c387a
111 	},
112 	{ }
113 };
114 MODULE_DEVICE_TABLE(of, rs5c372_of_match);
115 
116 /* REVISIT:  this assumes that:
117  *  - we're in the 21st century, so it's safe to ignore the century
118  *    bit for rv5c38[67] (REG_MONTH bit 7);
119  *  - we should use ALARM_A not ALARM_B (may be wrong on some boards)
120  */
121 struct rs5c372 {
122 	struct i2c_client	*client;
123 	struct rtc_device	*rtc;
124 	enum rtc_type		type;
125 	unsigned		time24:1;
126 	unsigned		has_irq:1;
127 	unsigned		smbus:1;
128 	char			buf[17];
129 	char			*regs;
130 };
131 
132 static int rs5c_get_regs(struct rs5c372 *rs5c)
133 {
134 	struct i2c_client	*client = rs5c->client;
135 	struct i2c_msg		msgs[] = {
136 		{
137 			.addr = client->addr,
138 			.flags = I2C_M_RD,
139 			.len = sizeof(rs5c->buf),
140 			.buf = rs5c->buf
141 		},
142 	};
143 
144 	/* This implements the third reading method from the datasheet, using
145 	 * an internal address that's reset after each transaction (by STOP)
146 	 * to 0x0f ... so we read extra registers, and skip the first one.
147 	 *
148 	 * The first method doesn't work with the iop3xx adapter driver, on at
149 	 * least 80219 chips; this works around that bug.
150 	 *
151 	 * The third method on the other hand doesn't work for the SMBus-only
152 	 * configurations, so we use the the first method there, stripping off
153 	 * the extra register in the process.
154 	 */
155 	if (rs5c->smbus) {
156 		int addr = RS5C_ADDR(RS5C372_REG_SECS);
157 		int size = sizeof(rs5c->buf) - 1;
158 
159 		if (i2c_smbus_read_i2c_block_data(client, addr, size,
160 						  rs5c->buf + 1) != size) {
161 			dev_warn(&client->dev, "can't read registers\n");
162 			return -EIO;
163 		}
164 	} else {
165 		if ((i2c_transfer(client->adapter, msgs, 1)) != 1) {
166 			dev_warn(&client->dev, "can't read registers\n");
167 			return -EIO;
168 		}
169 	}
170 
171 	dev_dbg(&client->dev,
172 		"%3ph (%02x) %3ph (%02x), %3ph, %3ph; %02x %02x\n",
173 		rs5c->regs + 0, rs5c->regs[3],
174 		rs5c->regs + 4, rs5c->regs[7],
175 		rs5c->regs + 8, rs5c->regs + 11,
176 		rs5c->regs[14], rs5c->regs[15]);
177 
178 	return 0;
179 }
180 
181 static unsigned rs5c_reg2hr(struct rs5c372 *rs5c, unsigned reg)
182 {
183 	unsigned	hour;
184 
185 	if (rs5c->time24)
186 		return bcd2bin(reg & 0x3f);
187 
188 	hour = bcd2bin(reg & 0x1f);
189 	if (hour == 12)
190 		hour = 0;
191 	if (reg & 0x20)
192 		hour += 12;
193 	return hour;
194 }
195 
196 static unsigned rs5c_hr2reg(struct rs5c372 *rs5c, unsigned hour)
197 {
198 	if (rs5c->time24)
199 		return bin2bcd(hour);
200 
201 	if (hour > 12)
202 		return 0x20 | bin2bcd(hour - 12);
203 	if (hour == 12)
204 		return 0x20 | bin2bcd(12);
205 	if (hour == 0)
206 		return bin2bcd(12);
207 	return bin2bcd(hour);
208 }
209 
210 static int rs5c372_get_datetime(struct i2c_client *client, struct rtc_time *tm)
211 {
212 	struct rs5c372	*rs5c = i2c_get_clientdata(client);
213 	int		status = rs5c_get_regs(rs5c);
214 
215 	if (status < 0)
216 		return status;
217 
218 	tm->tm_sec = bcd2bin(rs5c->regs[RS5C372_REG_SECS] & 0x7f);
219 	tm->tm_min = bcd2bin(rs5c->regs[RS5C372_REG_MINS] & 0x7f);
220 	tm->tm_hour = rs5c_reg2hr(rs5c, rs5c->regs[RS5C372_REG_HOURS]);
221 
222 	tm->tm_wday = bcd2bin(rs5c->regs[RS5C372_REG_WDAY] & 0x07);
223 	tm->tm_mday = bcd2bin(rs5c->regs[RS5C372_REG_DAY] & 0x3f);
224 
225 	/* tm->tm_mon is zero-based */
226 	tm->tm_mon = bcd2bin(rs5c->regs[RS5C372_REG_MONTH] & 0x1f) - 1;
227 
228 	/* year is 1900 + tm->tm_year */
229 	tm->tm_year = bcd2bin(rs5c->regs[RS5C372_REG_YEAR]) + 100;
230 
231 	dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
232 		"mday=%d, mon=%d, year=%d, wday=%d\n",
233 		__func__,
234 		tm->tm_sec, tm->tm_min, tm->tm_hour,
235 		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
236 
237 	/* rtc might need initialization */
238 	return rtc_valid_tm(tm);
239 }
240 
241 static int rs5c372_set_datetime(struct i2c_client *client, struct rtc_time *tm)
242 {
243 	struct rs5c372	*rs5c = i2c_get_clientdata(client);
244 	unsigned char	buf[7];
245 	int		addr;
246 
247 	dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d "
248 		"mday=%d, mon=%d, year=%d, wday=%d\n",
249 		__func__,
250 		tm->tm_sec, tm->tm_min, tm->tm_hour,
251 		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
252 
253 	addr   = RS5C_ADDR(RS5C372_REG_SECS);
254 	buf[0] = bin2bcd(tm->tm_sec);
255 	buf[1] = bin2bcd(tm->tm_min);
256 	buf[2] = rs5c_hr2reg(rs5c, tm->tm_hour);
257 	buf[3] = bin2bcd(tm->tm_wday);
258 	buf[4] = bin2bcd(tm->tm_mday);
259 	buf[5] = bin2bcd(tm->tm_mon + 1);
260 	buf[6] = bin2bcd(tm->tm_year - 100);
261 
262 	if (i2c_smbus_write_i2c_block_data(client, addr, sizeof(buf), buf) < 0) {
263 		dev_err(&client->dev, "%s: write error\n", __func__);
264 		return -EIO;
265 	}
266 
267 	return 0;
268 }
269 
270 #if IS_ENABLED(CONFIG_RTC_INTF_PROC)
271 #define	NEED_TRIM
272 #endif
273 
274 #if IS_ENABLED(CONFIG_RTC_INTF_SYSFS)
275 #define	NEED_TRIM
276 #endif
277 
278 #ifdef	NEED_TRIM
279 static int rs5c372_get_trim(struct i2c_client *client, int *osc, int *trim)
280 {
281 	struct rs5c372 *rs5c372 = i2c_get_clientdata(client);
282 	u8 tmp = rs5c372->regs[RS5C372_REG_TRIM];
283 
284 	if (osc)
285 		*osc = (tmp & RS5C372_TRIM_XSL) ? 32000 : 32768;
286 
287 	if (trim) {
288 		dev_dbg(&client->dev, "%s: raw trim=%x\n", __func__, tmp);
289 		tmp &= RS5C372_TRIM_MASK;
290 		if (tmp & 0x3e) {
291 			int t = tmp & 0x3f;
292 
293 			if (tmp & 0x40)
294 				t = (~t | (s8)0xc0) + 1;
295 			else
296 				t = t - 1;
297 
298 			tmp = t * 2;
299 		} else
300 			tmp = 0;
301 		*trim = tmp;
302 	}
303 
304 	return 0;
305 }
306 #endif
307 
308 static int rs5c372_rtc_read_time(struct device *dev, struct rtc_time *tm)
309 {
310 	return rs5c372_get_datetime(to_i2c_client(dev), tm);
311 }
312 
313 static int rs5c372_rtc_set_time(struct device *dev, struct rtc_time *tm)
314 {
315 	return rs5c372_set_datetime(to_i2c_client(dev), tm);
316 }
317 
318 
319 static int rs5c_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
320 {
321 	struct i2c_client	*client = to_i2c_client(dev);
322 	struct rs5c372		*rs5c = i2c_get_clientdata(client);
323 	unsigned char		buf;
324 	int			status, addr;
325 
326 	buf = rs5c->regs[RS5C_REG_CTRL1];
327 
328 	if (!rs5c->has_irq)
329 		return -EINVAL;
330 
331 	status = rs5c_get_regs(rs5c);
332 	if (status < 0)
333 		return status;
334 
335 	addr = RS5C_ADDR(RS5C_REG_CTRL1);
336 	if (enabled)
337 		buf |= RS5C_CTRL1_AALE;
338 	else
339 		buf &= ~RS5C_CTRL1_AALE;
340 
341 	if (i2c_smbus_write_byte_data(client, addr, buf) < 0) {
342 		dev_warn(dev, "can't update alarm\n");
343 		status = -EIO;
344 	} else
345 		rs5c->regs[RS5C_REG_CTRL1] = buf;
346 
347 	return status;
348 }
349 
350 
351 /* NOTE:  Since RTC_WKALM_{RD,SET} were originally defined for EFI,
352  * which only exposes a polled programming interface; and since
353  * these calls map directly to those EFI requests; we don't demand
354  * we have an IRQ for this chip when we go through this API.
355  *
356  * The older x86_pc derived RTC_ALM_{READ,SET} calls require irqs
357  * though, managed through RTC_AIE_{ON,OFF} requests.
358  */
359 
360 static int rs5c_read_alarm(struct device *dev, struct rtc_wkalrm *t)
361 {
362 	struct i2c_client	*client = to_i2c_client(dev);
363 	struct rs5c372		*rs5c = i2c_get_clientdata(client);
364 	int			status;
365 
366 	status = rs5c_get_regs(rs5c);
367 	if (status < 0)
368 		return status;
369 
370 	/* report alarm time */
371 	t->time.tm_sec = 0;
372 	t->time.tm_min = bcd2bin(rs5c->regs[RS5C_REG_ALARM_A_MIN] & 0x7f);
373 	t->time.tm_hour = rs5c_reg2hr(rs5c, rs5c->regs[RS5C_REG_ALARM_A_HOURS]);
374 
375 	/* ... and status */
376 	t->enabled = !!(rs5c->regs[RS5C_REG_CTRL1] & RS5C_CTRL1_AALE);
377 	t->pending = !!(rs5c->regs[RS5C_REG_CTRL2] & RS5C_CTRL2_AAFG);
378 
379 	return 0;
380 }
381 
382 static int rs5c_set_alarm(struct device *dev, struct rtc_wkalrm *t)
383 {
384 	struct i2c_client	*client = to_i2c_client(dev);
385 	struct rs5c372		*rs5c = i2c_get_clientdata(client);
386 	int			status, addr, i;
387 	unsigned char		buf[3];
388 
389 	/* only handle up to 24 hours in the future, like RTC_ALM_SET */
390 	if (t->time.tm_mday != -1
391 			|| t->time.tm_mon != -1
392 			|| t->time.tm_year != -1)
393 		return -EINVAL;
394 
395 	/* REVISIT: round up tm_sec */
396 
397 	/* if needed, disable irq (clears pending status) */
398 	status = rs5c_get_regs(rs5c);
399 	if (status < 0)
400 		return status;
401 	if (rs5c->regs[RS5C_REG_CTRL1] & RS5C_CTRL1_AALE) {
402 		addr = RS5C_ADDR(RS5C_REG_CTRL1);
403 		buf[0] = rs5c->regs[RS5C_REG_CTRL1] & ~RS5C_CTRL1_AALE;
404 		if (i2c_smbus_write_byte_data(client, addr, buf[0]) < 0) {
405 			dev_dbg(dev, "can't disable alarm\n");
406 			return -EIO;
407 		}
408 		rs5c->regs[RS5C_REG_CTRL1] = buf[0];
409 	}
410 
411 	/* set alarm */
412 	buf[0] = bin2bcd(t->time.tm_min);
413 	buf[1] = rs5c_hr2reg(rs5c, t->time.tm_hour);
414 	buf[2] = 0x7f;	/* any/all days */
415 
416 	for (i = 0; i < sizeof(buf); i++) {
417 		addr = RS5C_ADDR(RS5C_REG_ALARM_A_MIN + i);
418 		if (i2c_smbus_write_byte_data(client, addr, buf[i]) < 0) {
419 			dev_dbg(dev, "can't set alarm time\n");
420 			return -EIO;
421 		}
422 	}
423 
424 	/* ... and maybe enable its irq */
425 	if (t->enabled) {
426 		addr = RS5C_ADDR(RS5C_REG_CTRL1);
427 		buf[0] = rs5c->regs[RS5C_REG_CTRL1] | RS5C_CTRL1_AALE;
428 		if (i2c_smbus_write_byte_data(client, addr, buf[0]) < 0)
429 			dev_warn(dev, "can't enable alarm\n");
430 		rs5c->regs[RS5C_REG_CTRL1] = buf[0];
431 	}
432 
433 	return 0;
434 }
435 
436 #if IS_ENABLED(CONFIG_RTC_INTF_PROC)
437 
438 static int rs5c372_rtc_proc(struct device *dev, struct seq_file *seq)
439 {
440 	int err, osc, trim;
441 
442 	err = rs5c372_get_trim(to_i2c_client(dev), &osc, &trim);
443 	if (err == 0) {
444 		seq_printf(seq, "crystal\t\t: %d.%03d KHz\n",
445 				osc / 1000, osc % 1000);
446 		seq_printf(seq, "trim\t\t: %d\n", trim);
447 	}
448 
449 	return 0;
450 }
451 
452 #else
453 #define	rs5c372_rtc_proc	NULL
454 #endif
455 
456 static const struct rtc_class_ops rs5c372_rtc_ops = {
457 	.proc		= rs5c372_rtc_proc,
458 	.read_time	= rs5c372_rtc_read_time,
459 	.set_time	= rs5c372_rtc_set_time,
460 	.read_alarm	= rs5c_read_alarm,
461 	.set_alarm	= rs5c_set_alarm,
462 	.alarm_irq_enable = rs5c_rtc_alarm_irq_enable,
463 };
464 
465 #if IS_ENABLED(CONFIG_RTC_INTF_SYSFS)
466 
467 static ssize_t rs5c372_sysfs_show_trim(struct device *dev,
468 				struct device_attribute *attr, char *buf)
469 {
470 	int err, trim;
471 
472 	err = rs5c372_get_trim(to_i2c_client(dev), NULL, &trim);
473 	if (err)
474 		return err;
475 
476 	return sprintf(buf, "%d\n", trim);
477 }
478 static DEVICE_ATTR(trim, S_IRUGO, rs5c372_sysfs_show_trim, NULL);
479 
480 static ssize_t rs5c372_sysfs_show_osc(struct device *dev,
481 				struct device_attribute *attr, char *buf)
482 {
483 	int err, osc;
484 
485 	err = rs5c372_get_trim(to_i2c_client(dev), &osc, NULL);
486 	if (err)
487 		return err;
488 
489 	return sprintf(buf, "%d.%03d KHz\n", osc / 1000, osc % 1000);
490 }
491 static DEVICE_ATTR(osc, S_IRUGO, rs5c372_sysfs_show_osc, NULL);
492 
493 static int rs5c_sysfs_register(struct device *dev)
494 {
495 	int err;
496 
497 	err = device_create_file(dev, &dev_attr_trim);
498 	if (err)
499 		return err;
500 	err = device_create_file(dev, &dev_attr_osc);
501 	if (err)
502 		device_remove_file(dev, &dev_attr_trim);
503 
504 	return err;
505 }
506 
507 static void rs5c_sysfs_unregister(struct device *dev)
508 {
509 	device_remove_file(dev, &dev_attr_trim);
510 	device_remove_file(dev, &dev_attr_osc);
511 }
512 
513 #else
514 static int rs5c_sysfs_register(struct device *dev)
515 {
516 	return 0;
517 }
518 
519 static void rs5c_sysfs_unregister(struct device *dev)
520 {
521 	/* nothing */
522 }
523 #endif	/* SYSFS */
524 
525 static struct i2c_driver rs5c372_driver;
526 
527 static int rs5c_oscillator_setup(struct rs5c372 *rs5c372)
528 {
529 	unsigned char buf[2];
530 	int addr, i, ret = 0;
531 
532 	if (rs5c372->type == rtc_r2025sd) {
533 		if (rs5c372->regs[RS5C_REG_CTRL2] & R2025_CTRL2_XST)
534 			return ret;
535 		rs5c372->regs[RS5C_REG_CTRL2] |= R2025_CTRL2_XST;
536 	} else {
537 		if (!(rs5c372->regs[RS5C_REG_CTRL2] & RS5C_CTRL2_XSTP))
538 			return ret;
539 		rs5c372->regs[RS5C_REG_CTRL2] &= ~RS5C_CTRL2_XSTP;
540 	}
541 
542 	addr   = RS5C_ADDR(RS5C_REG_CTRL1);
543 	buf[0] = rs5c372->regs[RS5C_REG_CTRL1];
544 	buf[1] = rs5c372->regs[RS5C_REG_CTRL2];
545 
546 	/* use 24hr mode */
547 	switch (rs5c372->type) {
548 	case rtc_rs5c372a:
549 	case rtc_rs5c372b:
550 		buf[1] |= RS5C372_CTRL2_24;
551 		rs5c372->time24 = 1;
552 		break;
553 	case rtc_r2025sd:
554 	case rtc_r2221tl:
555 	case rtc_rv5c386:
556 	case rtc_rv5c387a:
557 		buf[0] |= RV5C387_CTRL1_24;
558 		rs5c372->time24 = 1;
559 		break;
560 	default:
561 		/* impossible */
562 		break;
563 	}
564 
565 	for (i = 0; i < sizeof(buf); i++) {
566 		addr = RS5C_ADDR(RS5C_REG_CTRL1 + i);
567 		ret = i2c_smbus_write_byte_data(rs5c372->client, addr, buf[i]);
568 		if (unlikely(ret < 0))
569 			return ret;
570 	}
571 
572 	rs5c372->regs[RS5C_REG_CTRL1] = buf[0];
573 	rs5c372->regs[RS5C_REG_CTRL2] = buf[1];
574 
575 	return 0;
576 }
577 
578 static int rs5c372_probe(struct i2c_client *client,
579 			 const struct i2c_device_id *id)
580 {
581 	int err = 0;
582 	int smbus_mode = 0;
583 	struct rs5c372 *rs5c372;
584 	struct rtc_time tm;
585 
586 	dev_dbg(&client->dev, "%s\n", __func__);
587 
588 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
589 			I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK)) {
590 		/*
591 		 * If we don't have any master mode adapter, try breaking
592 		 * it down in to the barest of capabilities.
593 		 */
594 		if (i2c_check_functionality(client->adapter,
595 				I2C_FUNC_SMBUS_BYTE_DATA |
596 				I2C_FUNC_SMBUS_I2C_BLOCK))
597 			smbus_mode = 1;
598 		else {
599 			/* Still no good, give up */
600 			err = -ENODEV;
601 			goto exit;
602 		}
603 	}
604 
605 	rs5c372 = devm_kzalloc(&client->dev, sizeof(struct rs5c372),
606 				GFP_KERNEL);
607 	if (!rs5c372) {
608 		err = -ENOMEM;
609 		goto exit;
610 	}
611 
612 	rs5c372->client = client;
613 	i2c_set_clientdata(client, rs5c372);
614 	if (client->dev.of_node)
615 		rs5c372->type = (enum rtc_type)
616 			of_device_get_match_data(&client->dev);
617 	else
618 		rs5c372->type = id->driver_data;
619 
620 	/* we read registers 0x0f then 0x00-0x0f; skip the first one */
621 	rs5c372->regs = &rs5c372->buf[1];
622 	rs5c372->smbus = smbus_mode;
623 
624 	err = rs5c_get_regs(rs5c372);
625 	if (err < 0)
626 		goto exit;
627 
628 	/* clock may be set for am/pm or 24 hr time */
629 	switch (rs5c372->type) {
630 	case rtc_rs5c372a:
631 	case rtc_rs5c372b:
632 		/* alarm uses ALARM_A; and nINTRA on 372a, nINTR on 372b.
633 		 * so does periodic irq, except some 327a modes.
634 		 */
635 		if (rs5c372->regs[RS5C_REG_CTRL2] & RS5C372_CTRL2_24)
636 			rs5c372->time24 = 1;
637 		break;
638 	case rtc_r2025sd:
639 	case rtc_r2221tl:
640 	case rtc_rv5c386:
641 	case rtc_rv5c387a:
642 		if (rs5c372->regs[RS5C_REG_CTRL1] & RV5C387_CTRL1_24)
643 			rs5c372->time24 = 1;
644 		/* alarm uses ALARM_W; and nINTRB for alarm and periodic
645 		 * irq, on both 386 and 387
646 		 */
647 		break;
648 	default:
649 		dev_err(&client->dev, "unknown RTC type\n");
650 		goto exit;
651 	}
652 
653 	/* if the oscillator lost power and no other software (like
654 	 * the bootloader) set it up, do it here.
655 	 *
656 	 * The R2025S/D does this a little differently than the other
657 	 * parts, so we special case that..
658 	 */
659 	err = rs5c_oscillator_setup(rs5c372);
660 	if (unlikely(err < 0)) {
661 		dev_err(&client->dev, "setup error\n");
662 		goto exit;
663 	}
664 
665 	if (rs5c372_get_datetime(client, &tm) < 0)
666 		dev_warn(&client->dev, "clock needs to be set\n");
667 
668 	dev_info(&client->dev, "%s found, %s\n",
669 			({ char *s; switch (rs5c372->type) {
670 			case rtc_r2025sd:	s = "r2025sd"; break;
671 			case rtc_r2221tl:	s = "r2221tl"; break;
672 			case rtc_rs5c372a:	s = "rs5c372a"; break;
673 			case rtc_rs5c372b:	s = "rs5c372b"; break;
674 			case rtc_rv5c386:	s = "rv5c386"; break;
675 			case rtc_rv5c387a:	s = "rv5c387a"; break;
676 			default:		s = "chip"; break;
677 			}; s;}),
678 			rs5c372->time24 ? "24hr" : "am/pm"
679 			);
680 
681 	/* REVISIT use client->irq to register alarm irq ... */
682 	rs5c372->rtc = devm_rtc_device_register(&client->dev,
683 					rs5c372_driver.driver.name,
684 					&rs5c372_rtc_ops, THIS_MODULE);
685 
686 	if (IS_ERR(rs5c372->rtc)) {
687 		err = PTR_ERR(rs5c372->rtc);
688 		goto exit;
689 	}
690 
691 	err = rs5c_sysfs_register(&client->dev);
692 	if (err)
693 		goto exit;
694 
695 	return 0;
696 
697 exit:
698 	return err;
699 }
700 
701 static int rs5c372_remove(struct i2c_client *client)
702 {
703 	rs5c_sysfs_unregister(&client->dev);
704 	return 0;
705 }
706 
707 static struct i2c_driver rs5c372_driver = {
708 	.driver		= {
709 		.name	= "rtc-rs5c372",
710 		.of_match_table = of_match_ptr(rs5c372_of_match),
711 	},
712 	.probe		= rs5c372_probe,
713 	.remove		= rs5c372_remove,
714 	.id_table	= rs5c372_id,
715 };
716 
717 module_i2c_driver(rs5c372_driver);
718 
719 MODULE_AUTHOR(
720 		"Pavel Mironchik <pmironchik@optifacio.net>, "
721 		"Alessandro Zummo <a.zummo@towertech.it>, "
722 		"Paul Mundt <lethal@linux-sh.org>");
723 MODULE_DESCRIPTION("Ricoh RS5C372 RTC driver");
724 MODULE_LICENSE("GPL");
725