xref: /openbmc/linux/drivers/rtc/rtc-rs5c372.c (revision 4f6cce39)
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 
19 /*
20  * Ricoh has a family of I2C based RTCs, which differ only slightly from
21  * each other.  Differences center on pinout (e.g. how many interrupts,
22  * output clock, etc) and how the control registers are used.  The '372
23  * is significant only because that's the one this driver first supported.
24  */
25 #define RS5C372_REG_SECS	0
26 #define RS5C372_REG_MINS	1
27 #define RS5C372_REG_HOURS	2
28 #define RS5C372_REG_WDAY	3
29 #define RS5C372_REG_DAY		4
30 #define RS5C372_REG_MONTH	5
31 #define RS5C372_REG_YEAR	6
32 #define RS5C372_REG_TRIM	7
33 #	define RS5C372_TRIM_XSL		0x80
34 #	define RS5C372_TRIM_MASK	0x7F
35 
36 #define RS5C_REG_ALARM_A_MIN	8			/* or ALARM_W */
37 #define RS5C_REG_ALARM_A_HOURS	9
38 #define RS5C_REG_ALARM_A_WDAY	10
39 
40 #define RS5C_REG_ALARM_B_MIN	11			/* or ALARM_D */
41 #define RS5C_REG_ALARM_B_HOURS	12
42 #define RS5C_REG_ALARM_B_WDAY	13			/* (ALARM_B only) */
43 
44 #define RS5C_REG_CTRL1		14
45 #	define RS5C_CTRL1_AALE		(1 << 7)	/* or WALE */
46 #	define RS5C_CTRL1_BALE		(1 << 6)	/* or DALE */
47 #	define RV5C387_CTRL1_24		(1 << 5)
48 #	define RS5C372A_CTRL1_SL1	(1 << 5)
49 #	define RS5C_CTRL1_CT_MASK	(7 << 0)
50 #	define RS5C_CTRL1_CT0		(0 << 0)	/* no periodic irq */
51 #	define RS5C_CTRL1_CT4		(4 << 0)	/* 1 Hz level irq */
52 #define RS5C_REG_CTRL2		15
53 #	define RS5C372_CTRL2_24		(1 << 5)
54 #	define R2025_CTRL2_XST		(1 << 5)
55 #	define RS5C_CTRL2_XSTP		(1 << 4)	/* only if !R2025S/D */
56 #	define RS5C_CTRL2_CTFG		(1 << 2)
57 #	define RS5C_CTRL2_AAFG		(1 << 1)	/* or WAFG */
58 #	define RS5C_CTRL2_BAFG		(1 << 0)	/* or DAFG */
59 
60 
61 /* to read (style 1) or write registers starting at R */
62 #define RS5C_ADDR(R)		(((R) << 4) | 0)
63 
64 
65 enum rtc_type {
66 	rtc_undef = 0,
67 	rtc_r2025sd,
68 	rtc_r2221tl,
69 	rtc_rs5c372a,
70 	rtc_rs5c372b,
71 	rtc_rv5c386,
72 	rtc_rv5c387a,
73 };
74 
75 static const struct i2c_device_id rs5c372_id[] = {
76 	{ "r2025sd", rtc_r2025sd },
77 	{ "r2221tl", rtc_r2221tl },
78 	{ "rs5c372a", rtc_rs5c372a },
79 	{ "rs5c372b", rtc_rs5c372b },
80 	{ "rv5c386", rtc_rv5c386 },
81 	{ "rv5c387a", rtc_rv5c387a },
82 	{ }
83 };
84 MODULE_DEVICE_TABLE(i2c, rs5c372_id);
85 
86 /* REVISIT:  this assumes that:
87  *  - we're in the 21st century, so it's safe to ignore the century
88  *    bit for rv5c38[67] (REG_MONTH bit 7);
89  *  - we should use ALARM_A not ALARM_B (may be wrong on some boards)
90  */
91 struct rs5c372 {
92 	struct i2c_client	*client;
93 	struct rtc_device	*rtc;
94 	enum rtc_type		type;
95 	unsigned		time24:1;
96 	unsigned		has_irq:1;
97 	unsigned		smbus:1;
98 	char			buf[17];
99 	char			*regs;
100 };
101 
102 static int rs5c_get_regs(struct rs5c372 *rs5c)
103 {
104 	struct i2c_client	*client = rs5c->client;
105 	struct i2c_msg		msgs[] = {
106 		{
107 			.addr = client->addr,
108 			.flags = I2C_M_RD,
109 			.len = sizeof(rs5c->buf),
110 			.buf = rs5c->buf
111 		},
112 	};
113 
114 	/* This implements the third reading method from the datasheet, using
115 	 * an internal address that's reset after each transaction (by STOP)
116 	 * to 0x0f ... so we read extra registers, and skip the first one.
117 	 *
118 	 * The first method doesn't work with the iop3xx adapter driver, on at
119 	 * least 80219 chips; this works around that bug.
120 	 *
121 	 * The third method on the other hand doesn't work for the SMBus-only
122 	 * configurations, so we use the the first method there, stripping off
123 	 * the extra register in the process.
124 	 */
125 	if (rs5c->smbus) {
126 		int addr = RS5C_ADDR(RS5C372_REG_SECS);
127 		int size = sizeof(rs5c->buf) - 1;
128 
129 		if (i2c_smbus_read_i2c_block_data(client, addr, size,
130 						  rs5c->buf + 1) != size) {
131 			dev_warn(&client->dev, "can't read registers\n");
132 			return -EIO;
133 		}
134 	} else {
135 		if ((i2c_transfer(client->adapter, msgs, 1)) != 1) {
136 			dev_warn(&client->dev, "can't read registers\n");
137 			return -EIO;
138 		}
139 	}
140 
141 	dev_dbg(&client->dev,
142 		"%3ph (%02x) %3ph (%02x), %3ph, %3ph; %02x %02x\n",
143 		rs5c->regs + 0, rs5c->regs[3],
144 		rs5c->regs + 4, rs5c->regs[7],
145 		rs5c->regs + 8, rs5c->regs + 11,
146 		rs5c->regs[14], rs5c->regs[15]);
147 
148 	return 0;
149 }
150 
151 static unsigned rs5c_reg2hr(struct rs5c372 *rs5c, unsigned reg)
152 {
153 	unsigned	hour;
154 
155 	if (rs5c->time24)
156 		return bcd2bin(reg & 0x3f);
157 
158 	hour = bcd2bin(reg & 0x1f);
159 	if (hour == 12)
160 		hour = 0;
161 	if (reg & 0x20)
162 		hour += 12;
163 	return hour;
164 }
165 
166 static unsigned rs5c_hr2reg(struct rs5c372 *rs5c, unsigned hour)
167 {
168 	if (rs5c->time24)
169 		return bin2bcd(hour);
170 
171 	if (hour > 12)
172 		return 0x20 | bin2bcd(hour - 12);
173 	if (hour == 12)
174 		return 0x20 | bin2bcd(12);
175 	if (hour == 0)
176 		return bin2bcd(12);
177 	return bin2bcd(hour);
178 }
179 
180 static int rs5c372_get_datetime(struct i2c_client *client, struct rtc_time *tm)
181 {
182 	struct rs5c372	*rs5c = i2c_get_clientdata(client);
183 	int		status = rs5c_get_regs(rs5c);
184 
185 	if (status < 0)
186 		return status;
187 
188 	tm->tm_sec = bcd2bin(rs5c->regs[RS5C372_REG_SECS] & 0x7f);
189 	tm->tm_min = bcd2bin(rs5c->regs[RS5C372_REG_MINS] & 0x7f);
190 	tm->tm_hour = rs5c_reg2hr(rs5c, rs5c->regs[RS5C372_REG_HOURS]);
191 
192 	tm->tm_wday = bcd2bin(rs5c->regs[RS5C372_REG_WDAY] & 0x07);
193 	tm->tm_mday = bcd2bin(rs5c->regs[RS5C372_REG_DAY] & 0x3f);
194 
195 	/* tm->tm_mon is zero-based */
196 	tm->tm_mon = bcd2bin(rs5c->regs[RS5C372_REG_MONTH] & 0x1f) - 1;
197 
198 	/* year is 1900 + tm->tm_year */
199 	tm->tm_year = bcd2bin(rs5c->regs[RS5C372_REG_YEAR]) + 100;
200 
201 	dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
202 		"mday=%d, mon=%d, year=%d, wday=%d\n",
203 		__func__,
204 		tm->tm_sec, tm->tm_min, tm->tm_hour,
205 		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
206 
207 	/* rtc might need initialization */
208 	return rtc_valid_tm(tm);
209 }
210 
211 static int rs5c372_set_datetime(struct i2c_client *client, struct rtc_time *tm)
212 {
213 	struct rs5c372	*rs5c = i2c_get_clientdata(client);
214 	unsigned char	buf[7];
215 	int		addr;
216 
217 	dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d "
218 		"mday=%d, mon=%d, year=%d, wday=%d\n",
219 		__func__,
220 		tm->tm_sec, tm->tm_min, tm->tm_hour,
221 		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
222 
223 	addr   = RS5C_ADDR(RS5C372_REG_SECS);
224 	buf[0] = bin2bcd(tm->tm_sec);
225 	buf[1] = bin2bcd(tm->tm_min);
226 	buf[2] = rs5c_hr2reg(rs5c, tm->tm_hour);
227 	buf[3] = bin2bcd(tm->tm_wday);
228 	buf[4] = bin2bcd(tm->tm_mday);
229 	buf[5] = bin2bcd(tm->tm_mon + 1);
230 	buf[6] = bin2bcd(tm->tm_year - 100);
231 
232 	if (i2c_smbus_write_i2c_block_data(client, addr, sizeof(buf), buf) < 0) {
233 		dev_err(&client->dev, "%s: write error\n", __func__);
234 		return -EIO;
235 	}
236 
237 	return 0;
238 }
239 
240 #if IS_ENABLED(CONFIG_RTC_INTF_PROC)
241 #define	NEED_TRIM
242 #endif
243 
244 #if IS_ENABLED(CONFIG_RTC_INTF_SYSFS)
245 #define	NEED_TRIM
246 #endif
247 
248 #ifdef	NEED_TRIM
249 static int rs5c372_get_trim(struct i2c_client *client, int *osc, int *trim)
250 {
251 	struct rs5c372 *rs5c372 = i2c_get_clientdata(client);
252 	u8 tmp = rs5c372->regs[RS5C372_REG_TRIM];
253 
254 	if (osc)
255 		*osc = (tmp & RS5C372_TRIM_XSL) ? 32000 : 32768;
256 
257 	if (trim) {
258 		dev_dbg(&client->dev, "%s: raw trim=%x\n", __func__, tmp);
259 		tmp &= RS5C372_TRIM_MASK;
260 		if (tmp & 0x3e) {
261 			int t = tmp & 0x3f;
262 
263 			if (tmp & 0x40)
264 				t = (~t | (s8)0xc0) + 1;
265 			else
266 				t = t - 1;
267 
268 			tmp = t * 2;
269 		} else
270 			tmp = 0;
271 		*trim = tmp;
272 	}
273 
274 	return 0;
275 }
276 #endif
277 
278 static int rs5c372_rtc_read_time(struct device *dev, struct rtc_time *tm)
279 {
280 	return rs5c372_get_datetime(to_i2c_client(dev), tm);
281 }
282 
283 static int rs5c372_rtc_set_time(struct device *dev, struct rtc_time *tm)
284 {
285 	return rs5c372_set_datetime(to_i2c_client(dev), tm);
286 }
287 
288 
289 static int rs5c_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
290 {
291 	struct i2c_client	*client = to_i2c_client(dev);
292 	struct rs5c372		*rs5c = i2c_get_clientdata(client);
293 	unsigned char		buf;
294 	int			status, addr;
295 
296 	buf = rs5c->regs[RS5C_REG_CTRL1];
297 
298 	if (!rs5c->has_irq)
299 		return -EINVAL;
300 
301 	status = rs5c_get_regs(rs5c);
302 	if (status < 0)
303 		return status;
304 
305 	addr = RS5C_ADDR(RS5C_REG_CTRL1);
306 	if (enabled)
307 		buf |= RS5C_CTRL1_AALE;
308 	else
309 		buf &= ~RS5C_CTRL1_AALE;
310 
311 	if (i2c_smbus_write_byte_data(client, addr, buf) < 0) {
312 		dev_warn(dev, "can't update alarm\n");
313 		status = -EIO;
314 	} else
315 		rs5c->regs[RS5C_REG_CTRL1] = buf;
316 
317 	return status;
318 }
319 
320 
321 /* NOTE:  Since RTC_WKALM_{RD,SET} were originally defined for EFI,
322  * which only exposes a polled programming interface; and since
323  * these calls map directly to those EFI requests; we don't demand
324  * we have an IRQ for this chip when we go through this API.
325  *
326  * The older x86_pc derived RTC_ALM_{READ,SET} calls require irqs
327  * though, managed through RTC_AIE_{ON,OFF} requests.
328  */
329 
330 static int rs5c_read_alarm(struct device *dev, struct rtc_wkalrm *t)
331 {
332 	struct i2c_client	*client = to_i2c_client(dev);
333 	struct rs5c372		*rs5c = i2c_get_clientdata(client);
334 	int			status;
335 
336 	status = rs5c_get_regs(rs5c);
337 	if (status < 0)
338 		return status;
339 
340 	/* report alarm time */
341 	t->time.tm_sec = 0;
342 	t->time.tm_min = bcd2bin(rs5c->regs[RS5C_REG_ALARM_A_MIN] & 0x7f);
343 	t->time.tm_hour = rs5c_reg2hr(rs5c, rs5c->regs[RS5C_REG_ALARM_A_HOURS]);
344 
345 	/* ... and status */
346 	t->enabled = !!(rs5c->regs[RS5C_REG_CTRL1] & RS5C_CTRL1_AALE);
347 	t->pending = !!(rs5c->regs[RS5C_REG_CTRL2] & RS5C_CTRL2_AAFG);
348 
349 	return 0;
350 }
351 
352 static int rs5c_set_alarm(struct device *dev, struct rtc_wkalrm *t)
353 {
354 	struct i2c_client	*client = to_i2c_client(dev);
355 	struct rs5c372		*rs5c = i2c_get_clientdata(client);
356 	int			status, addr, i;
357 	unsigned char		buf[3];
358 
359 	/* only handle up to 24 hours in the future, like RTC_ALM_SET */
360 	if (t->time.tm_mday != -1
361 			|| t->time.tm_mon != -1
362 			|| t->time.tm_year != -1)
363 		return -EINVAL;
364 
365 	/* REVISIT: round up tm_sec */
366 
367 	/* if needed, disable irq (clears pending status) */
368 	status = rs5c_get_regs(rs5c);
369 	if (status < 0)
370 		return status;
371 	if (rs5c->regs[RS5C_REG_CTRL1] & RS5C_CTRL1_AALE) {
372 		addr = RS5C_ADDR(RS5C_REG_CTRL1);
373 		buf[0] = rs5c->regs[RS5C_REG_CTRL1] & ~RS5C_CTRL1_AALE;
374 		if (i2c_smbus_write_byte_data(client, addr, buf[0]) < 0) {
375 			dev_dbg(dev, "can't disable alarm\n");
376 			return -EIO;
377 		}
378 		rs5c->regs[RS5C_REG_CTRL1] = buf[0];
379 	}
380 
381 	/* set alarm */
382 	buf[0] = bin2bcd(t->time.tm_min);
383 	buf[1] = rs5c_hr2reg(rs5c, t->time.tm_hour);
384 	buf[2] = 0x7f;	/* any/all days */
385 
386 	for (i = 0; i < sizeof(buf); i++) {
387 		addr = RS5C_ADDR(RS5C_REG_ALARM_A_MIN + i);
388 		if (i2c_smbus_write_byte_data(client, addr, buf[i]) < 0) {
389 			dev_dbg(dev, "can't set alarm time\n");
390 			return -EIO;
391 		}
392 	}
393 
394 	/* ... and maybe enable its irq */
395 	if (t->enabled) {
396 		addr = RS5C_ADDR(RS5C_REG_CTRL1);
397 		buf[0] = rs5c->regs[RS5C_REG_CTRL1] | RS5C_CTRL1_AALE;
398 		if (i2c_smbus_write_byte_data(client, addr, buf[0]) < 0)
399 			dev_warn(dev, "can't enable alarm\n");
400 		rs5c->regs[RS5C_REG_CTRL1] = buf[0];
401 	}
402 
403 	return 0;
404 }
405 
406 #if IS_ENABLED(CONFIG_RTC_INTF_PROC)
407 
408 static int rs5c372_rtc_proc(struct device *dev, struct seq_file *seq)
409 {
410 	int err, osc, trim;
411 
412 	err = rs5c372_get_trim(to_i2c_client(dev), &osc, &trim);
413 	if (err == 0) {
414 		seq_printf(seq, "crystal\t\t: %d.%03d KHz\n",
415 				osc / 1000, osc % 1000);
416 		seq_printf(seq, "trim\t\t: %d\n", trim);
417 	}
418 
419 	return 0;
420 }
421 
422 #else
423 #define	rs5c372_rtc_proc	NULL
424 #endif
425 
426 static const struct rtc_class_ops rs5c372_rtc_ops = {
427 	.proc		= rs5c372_rtc_proc,
428 	.read_time	= rs5c372_rtc_read_time,
429 	.set_time	= rs5c372_rtc_set_time,
430 	.read_alarm	= rs5c_read_alarm,
431 	.set_alarm	= rs5c_set_alarm,
432 	.alarm_irq_enable = rs5c_rtc_alarm_irq_enable,
433 };
434 
435 #if IS_ENABLED(CONFIG_RTC_INTF_SYSFS)
436 
437 static ssize_t rs5c372_sysfs_show_trim(struct device *dev,
438 				struct device_attribute *attr, char *buf)
439 {
440 	int err, trim;
441 
442 	err = rs5c372_get_trim(to_i2c_client(dev), NULL, &trim);
443 	if (err)
444 		return err;
445 
446 	return sprintf(buf, "%d\n", trim);
447 }
448 static DEVICE_ATTR(trim, S_IRUGO, rs5c372_sysfs_show_trim, NULL);
449 
450 static ssize_t rs5c372_sysfs_show_osc(struct device *dev,
451 				struct device_attribute *attr, char *buf)
452 {
453 	int err, osc;
454 
455 	err = rs5c372_get_trim(to_i2c_client(dev), &osc, NULL);
456 	if (err)
457 		return err;
458 
459 	return sprintf(buf, "%d.%03d KHz\n", osc / 1000, osc % 1000);
460 }
461 static DEVICE_ATTR(osc, S_IRUGO, rs5c372_sysfs_show_osc, NULL);
462 
463 static int rs5c_sysfs_register(struct device *dev)
464 {
465 	int err;
466 
467 	err = device_create_file(dev, &dev_attr_trim);
468 	if (err)
469 		return err;
470 	err = device_create_file(dev, &dev_attr_osc);
471 	if (err)
472 		device_remove_file(dev, &dev_attr_trim);
473 
474 	return err;
475 }
476 
477 static void rs5c_sysfs_unregister(struct device *dev)
478 {
479 	device_remove_file(dev, &dev_attr_trim);
480 	device_remove_file(dev, &dev_attr_osc);
481 }
482 
483 #else
484 static int rs5c_sysfs_register(struct device *dev)
485 {
486 	return 0;
487 }
488 
489 static void rs5c_sysfs_unregister(struct device *dev)
490 {
491 	/* nothing */
492 }
493 #endif	/* SYSFS */
494 
495 static struct i2c_driver rs5c372_driver;
496 
497 static int rs5c_oscillator_setup(struct rs5c372 *rs5c372)
498 {
499 	unsigned char buf[2];
500 	int addr, i, ret = 0;
501 
502 	if (rs5c372->type == rtc_r2025sd) {
503 		if (rs5c372->regs[RS5C_REG_CTRL2] & R2025_CTRL2_XST)
504 			return ret;
505 		rs5c372->regs[RS5C_REG_CTRL2] |= R2025_CTRL2_XST;
506 	} else {
507 		if (!(rs5c372->regs[RS5C_REG_CTRL2] & RS5C_CTRL2_XSTP))
508 			return ret;
509 		rs5c372->regs[RS5C_REG_CTRL2] &= ~RS5C_CTRL2_XSTP;
510 	}
511 
512 	addr   = RS5C_ADDR(RS5C_REG_CTRL1);
513 	buf[0] = rs5c372->regs[RS5C_REG_CTRL1];
514 	buf[1] = rs5c372->regs[RS5C_REG_CTRL2];
515 
516 	/* use 24hr mode */
517 	switch (rs5c372->type) {
518 	case rtc_rs5c372a:
519 	case rtc_rs5c372b:
520 		buf[1] |= RS5C372_CTRL2_24;
521 		rs5c372->time24 = 1;
522 		break;
523 	case rtc_r2025sd:
524 	case rtc_r2221tl:
525 	case rtc_rv5c386:
526 	case rtc_rv5c387a:
527 		buf[0] |= RV5C387_CTRL1_24;
528 		rs5c372->time24 = 1;
529 		break;
530 	default:
531 		/* impossible */
532 		break;
533 	}
534 
535 	for (i = 0; i < sizeof(buf); i++) {
536 		addr = RS5C_ADDR(RS5C_REG_CTRL1 + i);
537 		ret = i2c_smbus_write_byte_data(rs5c372->client, addr, buf[i]);
538 		if (unlikely(ret < 0))
539 			return ret;
540 	}
541 
542 	rs5c372->regs[RS5C_REG_CTRL1] = buf[0];
543 	rs5c372->regs[RS5C_REG_CTRL2] = buf[1];
544 
545 	return 0;
546 }
547 
548 static int rs5c372_probe(struct i2c_client *client,
549 			 const struct i2c_device_id *id)
550 {
551 	int err = 0;
552 	int smbus_mode = 0;
553 	struct rs5c372 *rs5c372;
554 	struct rtc_time tm;
555 
556 	dev_dbg(&client->dev, "%s\n", __func__);
557 
558 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
559 			I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK)) {
560 		/*
561 		 * If we don't have any master mode adapter, try breaking
562 		 * it down in to the barest of capabilities.
563 		 */
564 		if (i2c_check_functionality(client->adapter,
565 				I2C_FUNC_SMBUS_BYTE_DATA |
566 				I2C_FUNC_SMBUS_I2C_BLOCK))
567 			smbus_mode = 1;
568 		else {
569 			/* Still no good, give up */
570 			err = -ENODEV;
571 			goto exit;
572 		}
573 	}
574 
575 	rs5c372 = devm_kzalloc(&client->dev, sizeof(struct rs5c372),
576 				GFP_KERNEL);
577 	if (!rs5c372) {
578 		err = -ENOMEM;
579 		goto exit;
580 	}
581 
582 	rs5c372->client = client;
583 	i2c_set_clientdata(client, rs5c372);
584 	rs5c372->type = id->driver_data;
585 
586 	/* we read registers 0x0f then 0x00-0x0f; skip the first one */
587 	rs5c372->regs = &rs5c372->buf[1];
588 	rs5c372->smbus = smbus_mode;
589 
590 	err = rs5c_get_regs(rs5c372);
591 	if (err < 0)
592 		goto exit;
593 
594 	/* clock may be set for am/pm or 24 hr time */
595 	switch (rs5c372->type) {
596 	case rtc_rs5c372a:
597 	case rtc_rs5c372b:
598 		/* alarm uses ALARM_A; and nINTRA on 372a, nINTR on 372b.
599 		 * so does periodic irq, except some 327a modes.
600 		 */
601 		if (rs5c372->regs[RS5C_REG_CTRL2] & RS5C372_CTRL2_24)
602 			rs5c372->time24 = 1;
603 		break;
604 	case rtc_r2025sd:
605 	case rtc_r2221tl:
606 	case rtc_rv5c386:
607 	case rtc_rv5c387a:
608 		if (rs5c372->regs[RS5C_REG_CTRL1] & RV5C387_CTRL1_24)
609 			rs5c372->time24 = 1;
610 		/* alarm uses ALARM_W; and nINTRB for alarm and periodic
611 		 * irq, on both 386 and 387
612 		 */
613 		break;
614 	default:
615 		dev_err(&client->dev, "unknown RTC type\n");
616 		goto exit;
617 	}
618 
619 	/* if the oscillator lost power and no other software (like
620 	 * the bootloader) set it up, do it here.
621 	 *
622 	 * The R2025S/D does this a little differently than the other
623 	 * parts, so we special case that..
624 	 */
625 	err = rs5c_oscillator_setup(rs5c372);
626 	if (unlikely(err < 0)) {
627 		dev_err(&client->dev, "setup error\n");
628 		goto exit;
629 	}
630 
631 	if (rs5c372_get_datetime(client, &tm) < 0)
632 		dev_warn(&client->dev, "clock needs to be set\n");
633 
634 	dev_info(&client->dev, "%s found, %s\n",
635 			({ char *s; switch (rs5c372->type) {
636 			case rtc_r2025sd:	s = "r2025sd"; break;
637 			case rtc_r2221tl:	s = "r2221tl"; break;
638 			case rtc_rs5c372a:	s = "rs5c372a"; break;
639 			case rtc_rs5c372b:	s = "rs5c372b"; break;
640 			case rtc_rv5c386:	s = "rv5c386"; break;
641 			case rtc_rv5c387a:	s = "rv5c387a"; break;
642 			default:		s = "chip"; break;
643 			}; s;}),
644 			rs5c372->time24 ? "24hr" : "am/pm"
645 			);
646 
647 	/* REVISIT use client->irq to register alarm irq ... */
648 	rs5c372->rtc = devm_rtc_device_register(&client->dev,
649 					rs5c372_driver.driver.name,
650 					&rs5c372_rtc_ops, THIS_MODULE);
651 
652 	if (IS_ERR(rs5c372->rtc)) {
653 		err = PTR_ERR(rs5c372->rtc);
654 		goto exit;
655 	}
656 
657 	err = rs5c_sysfs_register(&client->dev);
658 	if (err)
659 		goto exit;
660 
661 	return 0;
662 
663 exit:
664 	return err;
665 }
666 
667 static int rs5c372_remove(struct i2c_client *client)
668 {
669 	rs5c_sysfs_unregister(&client->dev);
670 	return 0;
671 }
672 
673 static struct i2c_driver rs5c372_driver = {
674 	.driver		= {
675 		.name	= "rtc-rs5c372",
676 	},
677 	.probe		= rs5c372_probe,
678 	.remove		= rs5c372_remove,
679 	.id_table	= rs5c372_id,
680 };
681 
682 module_i2c_driver(rs5c372_driver);
683 
684 MODULE_AUTHOR(
685 		"Pavel Mironchik <pmironchik@optifacio.net>, "
686 		"Alessandro Zummo <a.zummo@towertech.it>, "
687 		"Paul Mundt <lethal@linux-sh.org>");
688 MODULE_DESCRIPTION("Ricoh RS5C372 RTC driver");
689 MODULE_LICENSE("GPL");
690