xref: /openbmc/linux/drivers/rtc/rtc-rs5c372.c (revision 6a551c11)
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 	t->time.tm_mday = -1;
345 	t->time.tm_mon = -1;
346 	t->time.tm_year = -1;
347 	t->time.tm_wday = -1;
348 	t->time.tm_yday = -1;
349 	t->time.tm_isdst = -1;
350 
351 	/* ... and status */
352 	t->enabled = !!(rs5c->regs[RS5C_REG_CTRL1] & RS5C_CTRL1_AALE);
353 	t->pending = !!(rs5c->regs[RS5C_REG_CTRL2] & RS5C_CTRL2_AAFG);
354 
355 	return 0;
356 }
357 
358 static int rs5c_set_alarm(struct device *dev, struct rtc_wkalrm *t)
359 {
360 	struct i2c_client	*client = to_i2c_client(dev);
361 	struct rs5c372		*rs5c = i2c_get_clientdata(client);
362 	int			status, addr, i;
363 	unsigned char		buf[3];
364 
365 	/* only handle up to 24 hours in the future, like RTC_ALM_SET */
366 	if (t->time.tm_mday != -1
367 			|| t->time.tm_mon != -1
368 			|| t->time.tm_year != -1)
369 		return -EINVAL;
370 
371 	/* REVISIT: round up tm_sec */
372 
373 	/* if needed, disable irq (clears pending status) */
374 	status = rs5c_get_regs(rs5c);
375 	if (status < 0)
376 		return status;
377 	if (rs5c->regs[RS5C_REG_CTRL1] & RS5C_CTRL1_AALE) {
378 		addr = RS5C_ADDR(RS5C_REG_CTRL1);
379 		buf[0] = rs5c->regs[RS5C_REG_CTRL1] & ~RS5C_CTRL1_AALE;
380 		if (i2c_smbus_write_byte_data(client, addr, buf[0]) < 0) {
381 			dev_dbg(dev, "can't disable alarm\n");
382 			return -EIO;
383 		}
384 		rs5c->regs[RS5C_REG_CTRL1] = buf[0];
385 	}
386 
387 	/* set alarm */
388 	buf[0] = bin2bcd(t->time.tm_min);
389 	buf[1] = rs5c_hr2reg(rs5c, t->time.tm_hour);
390 	buf[2] = 0x7f;	/* any/all days */
391 
392 	for (i = 0; i < sizeof(buf); i++) {
393 		addr = RS5C_ADDR(RS5C_REG_ALARM_A_MIN + i);
394 		if (i2c_smbus_write_byte_data(client, addr, buf[i]) < 0) {
395 			dev_dbg(dev, "can't set alarm time\n");
396 			return -EIO;
397 		}
398 	}
399 
400 	/* ... and maybe enable its irq */
401 	if (t->enabled) {
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_warn(dev, "can't enable alarm\n");
406 		rs5c->regs[RS5C_REG_CTRL1] = buf[0];
407 	}
408 
409 	return 0;
410 }
411 
412 #if IS_ENABLED(CONFIG_RTC_INTF_PROC)
413 
414 static int rs5c372_rtc_proc(struct device *dev, struct seq_file *seq)
415 {
416 	int err, osc, trim;
417 
418 	err = rs5c372_get_trim(to_i2c_client(dev), &osc, &trim);
419 	if (err == 0) {
420 		seq_printf(seq, "crystal\t\t: %d.%03d KHz\n",
421 				osc / 1000, osc % 1000);
422 		seq_printf(seq, "trim\t\t: %d\n", trim);
423 	}
424 
425 	return 0;
426 }
427 
428 #else
429 #define	rs5c372_rtc_proc	NULL
430 #endif
431 
432 static const struct rtc_class_ops rs5c372_rtc_ops = {
433 	.proc		= rs5c372_rtc_proc,
434 	.read_time	= rs5c372_rtc_read_time,
435 	.set_time	= rs5c372_rtc_set_time,
436 	.read_alarm	= rs5c_read_alarm,
437 	.set_alarm	= rs5c_set_alarm,
438 	.alarm_irq_enable = rs5c_rtc_alarm_irq_enable,
439 };
440 
441 #if IS_ENABLED(CONFIG_RTC_INTF_SYSFS)
442 
443 static ssize_t rs5c372_sysfs_show_trim(struct device *dev,
444 				struct device_attribute *attr, char *buf)
445 {
446 	int err, trim;
447 
448 	err = rs5c372_get_trim(to_i2c_client(dev), NULL, &trim);
449 	if (err)
450 		return err;
451 
452 	return sprintf(buf, "%d\n", trim);
453 }
454 static DEVICE_ATTR(trim, S_IRUGO, rs5c372_sysfs_show_trim, NULL);
455 
456 static ssize_t rs5c372_sysfs_show_osc(struct device *dev,
457 				struct device_attribute *attr, char *buf)
458 {
459 	int err, osc;
460 
461 	err = rs5c372_get_trim(to_i2c_client(dev), &osc, NULL);
462 	if (err)
463 		return err;
464 
465 	return sprintf(buf, "%d.%03d KHz\n", osc / 1000, osc % 1000);
466 }
467 static DEVICE_ATTR(osc, S_IRUGO, rs5c372_sysfs_show_osc, NULL);
468 
469 static int rs5c_sysfs_register(struct device *dev)
470 {
471 	int err;
472 
473 	err = device_create_file(dev, &dev_attr_trim);
474 	if (err)
475 		return err;
476 	err = device_create_file(dev, &dev_attr_osc);
477 	if (err)
478 		device_remove_file(dev, &dev_attr_trim);
479 
480 	return err;
481 }
482 
483 static void rs5c_sysfs_unregister(struct device *dev)
484 {
485 	device_remove_file(dev, &dev_attr_trim);
486 	device_remove_file(dev, &dev_attr_osc);
487 }
488 
489 #else
490 static int rs5c_sysfs_register(struct device *dev)
491 {
492 	return 0;
493 }
494 
495 static void rs5c_sysfs_unregister(struct device *dev)
496 {
497 	/* nothing */
498 }
499 #endif	/* SYSFS */
500 
501 static struct i2c_driver rs5c372_driver;
502 
503 static int rs5c_oscillator_setup(struct rs5c372 *rs5c372)
504 {
505 	unsigned char buf[2];
506 	int addr, i, ret = 0;
507 
508 	if (rs5c372->type == rtc_r2025sd) {
509 		if (rs5c372->regs[RS5C_REG_CTRL2] & R2025_CTRL2_XST)
510 			return ret;
511 		rs5c372->regs[RS5C_REG_CTRL2] |= R2025_CTRL2_XST;
512 	} else {
513 		if (!(rs5c372->regs[RS5C_REG_CTRL2] & RS5C_CTRL2_XSTP))
514 			return ret;
515 		rs5c372->regs[RS5C_REG_CTRL2] &= ~RS5C_CTRL2_XSTP;
516 	}
517 
518 	addr   = RS5C_ADDR(RS5C_REG_CTRL1);
519 	buf[0] = rs5c372->regs[RS5C_REG_CTRL1];
520 	buf[1] = rs5c372->regs[RS5C_REG_CTRL2];
521 
522 	/* use 24hr mode */
523 	switch (rs5c372->type) {
524 	case rtc_rs5c372a:
525 	case rtc_rs5c372b:
526 		buf[1] |= RS5C372_CTRL2_24;
527 		rs5c372->time24 = 1;
528 		break;
529 	case rtc_r2025sd:
530 	case rtc_r2221tl:
531 	case rtc_rv5c386:
532 	case rtc_rv5c387a:
533 		buf[0] |= RV5C387_CTRL1_24;
534 		rs5c372->time24 = 1;
535 		break;
536 	default:
537 		/* impossible */
538 		break;
539 	}
540 
541 	for (i = 0; i < sizeof(buf); i++) {
542 		addr = RS5C_ADDR(RS5C_REG_CTRL1 + i);
543 		ret = i2c_smbus_write_byte_data(rs5c372->client, addr, buf[i]);
544 		if (unlikely(ret < 0))
545 			return ret;
546 	}
547 
548 	rs5c372->regs[RS5C_REG_CTRL1] = buf[0];
549 	rs5c372->regs[RS5C_REG_CTRL2] = buf[1];
550 
551 	return 0;
552 }
553 
554 static int rs5c372_probe(struct i2c_client *client,
555 			 const struct i2c_device_id *id)
556 {
557 	int err = 0;
558 	int smbus_mode = 0;
559 	struct rs5c372 *rs5c372;
560 	struct rtc_time tm;
561 
562 	dev_dbg(&client->dev, "%s\n", __func__);
563 
564 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
565 			I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK)) {
566 		/*
567 		 * If we don't have any master mode adapter, try breaking
568 		 * it down in to the barest of capabilities.
569 		 */
570 		if (i2c_check_functionality(client->adapter,
571 				I2C_FUNC_SMBUS_BYTE_DATA |
572 				I2C_FUNC_SMBUS_I2C_BLOCK))
573 			smbus_mode = 1;
574 		else {
575 			/* Still no good, give up */
576 			err = -ENODEV;
577 			goto exit;
578 		}
579 	}
580 
581 	rs5c372 = devm_kzalloc(&client->dev, sizeof(struct rs5c372),
582 				GFP_KERNEL);
583 	if (!rs5c372) {
584 		err = -ENOMEM;
585 		goto exit;
586 	}
587 
588 	rs5c372->client = client;
589 	i2c_set_clientdata(client, rs5c372);
590 	rs5c372->type = id->driver_data;
591 
592 	/* we read registers 0x0f then 0x00-0x0f; skip the first one */
593 	rs5c372->regs = &rs5c372->buf[1];
594 	rs5c372->smbus = smbus_mode;
595 
596 	err = rs5c_get_regs(rs5c372);
597 	if (err < 0)
598 		goto exit;
599 
600 	/* clock may be set for am/pm or 24 hr time */
601 	switch (rs5c372->type) {
602 	case rtc_rs5c372a:
603 	case rtc_rs5c372b:
604 		/* alarm uses ALARM_A; and nINTRA on 372a, nINTR on 372b.
605 		 * so does periodic irq, except some 327a modes.
606 		 */
607 		if (rs5c372->regs[RS5C_REG_CTRL2] & RS5C372_CTRL2_24)
608 			rs5c372->time24 = 1;
609 		break;
610 	case rtc_r2025sd:
611 	case rtc_r2221tl:
612 	case rtc_rv5c386:
613 	case rtc_rv5c387a:
614 		if (rs5c372->regs[RS5C_REG_CTRL1] & RV5C387_CTRL1_24)
615 			rs5c372->time24 = 1;
616 		/* alarm uses ALARM_W; and nINTRB for alarm and periodic
617 		 * irq, on both 386 and 387
618 		 */
619 		break;
620 	default:
621 		dev_err(&client->dev, "unknown RTC type\n");
622 		goto exit;
623 	}
624 
625 	/* if the oscillator lost power and no other software (like
626 	 * the bootloader) set it up, do it here.
627 	 *
628 	 * The R2025S/D does this a little differently than the other
629 	 * parts, so we special case that..
630 	 */
631 	err = rs5c_oscillator_setup(rs5c372);
632 	if (unlikely(err < 0)) {
633 		dev_err(&client->dev, "setup error\n");
634 		goto exit;
635 	}
636 
637 	if (rs5c372_get_datetime(client, &tm) < 0)
638 		dev_warn(&client->dev, "clock needs to be set\n");
639 
640 	dev_info(&client->dev, "%s found, %s\n",
641 			({ char *s; switch (rs5c372->type) {
642 			case rtc_r2025sd:	s = "r2025sd"; break;
643 			case rtc_r2221tl:	s = "r2221tl"; break;
644 			case rtc_rs5c372a:	s = "rs5c372a"; break;
645 			case rtc_rs5c372b:	s = "rs5c372b"; break;
646 			case rtc_rv5c386:	s = "rv5c386"; break;
647 			case rtc_rv5c387a:	s = "rv5c387a"; break;
648 			default:		s = "chip"; break;
649 			}; s;}),
650 			rs5c372->time24 ? "24hr" : "am/pm"
651 			);
652 
653 	/* REVISIT use client->irq to register alarm irq ... */
654 	rs5c372->rtc = devm_rtc_device_register(&client->dev,
655 					rs5c372_driver.driver.name,
656 					&rs5c372_rtc_ops, THIS_MODULE);
657 
658 	if (IS_ERR(rs5c372->rtc)) {
659 		err = PTR_ERR(rs5c372->rtc);
660 		goto exit;
661 	}
662 
663 	err = rs5c_sysfs_register(&client->dev);
664 	if (err)
665 		goto exit;
666 
667 	return 0;
668 
669 exit:
670 	return err;
671 }
672 
673 static int rs5c372_remove(struct i2c_client *client)
674 {
675 	rs5c_sysfs_unregister(&client->dev);
676 	return 0;
677 }
678 
679 static struct i2c_driver rs5c372_driver = {
680 	.driver		= {
681 		.name	= "rtc-rs5c372",
682 	},
683 	.probe		= rs5c372_probe,
684 	.remove		= rs5c372_remove,
685 	.id_table	= rs5c372_id,
686 };
687 
688 module_i2c_driver(rs5c372_driver);
689 
690 MODULE_AUTHOR(
691 		"Pavel Mironchik <pmironchik@optifacio.net>, "
692 		"Alessandro Zummo <a.zummo@towertech.it>, "
693 		"Paul Mundt <lethal@linux-sh.org>");
694 MODULE_DESCRIPTION("Ricoh RS5C372 RTC driver");
695 MODULE_LICENSE("GPL");
696