xref: /openbmc/linux/drivers/rtc/rtc-rs5c372.c (revision 12eb4683)
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 #define DRV_VERSION "0.6"
20 
21 
22 /*
23  * Ricoh has a family of I2C based RTCs, which differ only slightly from
24  * each other.  Differences center on pinout (e.g. how many interrupts,
25  * output clock, etc) and how the control registers are used.  The '372
26  * is significant only because that's the one this driver first supported.
27  */
28 #define RS5C372_REG_SECS	0
29 #define RS5C372_REG_MINS	1
30 #define RS5C372_REG_HOURS	2
31 #define RS5C372_REG_WDAY	3
32 #define RS5C372_REG_DAY		4
33 #define RS5C372_REG_MONTH	5
34 #define RS5C372_REG_YEAR	6
35 #define RS5C372_REG_TRIM	7
36 #	define RS5C372_TRIM_XSL		0x80
37 #	define RS5C372_TRIM_MASK	0x7F
38 
39 #define RS5C_REG_ALARM_A_MIN	8			/* or ALARM_W */
40 #define RS5C_REG_ALARM_A_HOURS	9
41 #define RS5C_REG_ALARM_A_WDAY	10
42 
43 #define RS5C_REG_ALARM_B_MIN	11			/* or ALARM_D */
44 #define RS5C_REG_ALARM_B_HOURS	12
45 #define RS5C_REG_ALARM_B_WDAY	13			/* (ALARM_B only) */
46 
47 #define RS5C_REG_CTRL1		14
48 #	define RS5C_CTRL1_AALE		(1 << 7)	/* or WALE */
49 #	define RS5C_CTRL1_BALE		(1 << 6)	/* or DALE */
50 #	define RV5C387_CTRL1_24		(1 << 5)
51 #	define RS5C372A_CTRL1_SL1	(1 << 5)
52 #	define RS5C_CTRL1_CT_MASK	(7 << 0)
53 #	define RS5C_CTRL1_CT0		(0 << 0)	/* no periodic irq */
54 #	define RS5C_CTRL1_CT4		(4 << 0)	/* 1 Hz level irq */
55 #define RS5C_REG_CTRL2		15
56 #	define RS5C372_CTRL2_24		(1 << 5)
57 #	define R2025_CTRL2_XST		(1 << 5)
58 #	define RS5C_CTRL2_XSTP		(1 << 4)	/* only if !R2025S/D */
59 #	define RS5C_CTRL2_CTFG		(1 << 2)
60 #	define RS5C_CTRL2_AAFG		(1 << 1)	/* or WAFG */
61 #	define RS5C_CTRL2_BAFG		(1 << 0)	/* or DAFG */
62 
63 
64 /* to read (style 1) or write registers starting at R */
65 #define RS5C_ADDR(R)		(((R) << 4) | 0)
66 
67 
68 enum rtc_type {
69 	rtc_undef = 0,
70 	rtc_r2025sd,
71 	rtc_r2221tl,
72 	rtc_rs5c372a,
73 	rtc_rs5c372b,
74 	rtc_rv5c386,
75 	rtc_rv5c387a,
76 };
77 
78 static const struct i2c_device_id rs5c372_id[] = {
79 	{ "r2025sd", rtc_r2025sd },
80 	{ "r2221tl", rtc_r2221tl },
81 	{ "rs5c372a", rtc_rs5c372a },
82 	{ "rs5c372b", rtc_rs5c372b },
83 	{ "rv5c386", rtc_rv5c386 },
84 	{ "rv5c387a", rtc_rv5c387a },
85 	{ }
86 };
87 MODULE_DEVICE_TABLE(i2c, rs5c372_id);
88 
89 /* REVISIT:  this assumes that:
90  *  - we're in the 21st century, so it's safe to ignore the century
91  *    bit for rv5c38[67] (REG_MONTH bit 7);
92  *  - we should use ALARM_A not ALARM_B (may be wrong on some boards)
93  */
94 struct rs5c372 {
95 	struct i2c_client	*client;
96 	struct rtc_device	*rtc;
97 	enum rtc_type		type;
98 	unsigned		time24:1;
99 	unsigned		has_irq:1;
100 	unsigned		smbus:1;
101 	char			buf[17];
102 	char			*regs;
103 };
104 
105 static int rs5c_get_regs(struct rs5c372 *rs5c)
106 {
107 	struct i2c_client	*client = rs5c->client;
108 	struct i2c_msg		msgs[] = {
109 		{
110 			.addr = client->addr,
111 			.flags = I2C_M_RD,
112 			.len = sizeof(rs5c->buf),
113 			.buf = rs5c->buf
114 		},
115 	};
116 
117 	/* This implements the third reading method from the datasheet, using
118 	 * an internal address that's reset after each transaction (by STOP)
119 	 * to 0x0f ... so we read extra registers, and skip the first one.
120 	 *
121 	 * The first method doesn't work with the iop3xx adapter driver, on at
122 	 * least 80219 chips; this works around that bug.
123 	 *
124 	 * The third method on the other hand doesn't work for the SMBus-only
125 	 * configurations, so we use the the first method there, stripping off
126 	 * the extra register in the process.
127 	 */
128 	if (rs5c->smbus) {
129 		int addr = RS5C_ADDR(RS5C372_REG_SECS);
130 		int size = sizeof(rs5c->buf) - 1;
131 
132 		if (i2c_smbus_read_i2c_block_data(client, addr, size,
133 						  rs5c->buf + 1) != size) {
134 			dev_warn(&client->dev, "can't read registers\n");
135 			return -EIO;
136 		}
137 	} else {
138 		if ((i2c_transfer(client->adapter, msgs, 1)) != 1) {
139 			dev_warn(&client->dev, "can't read registers\n");
140 			return -EIO;
141 		}
142 	}
143 
144 	dev_dbg(&client->dev,
145 		"%02x %02x %02x (%02x) %02x %02x %02x (%02x), "
146 		"%02x %02x %02x, %02x %02x %02x; %02x %02x\n",
147 		rs5c->regs[0],  rs5c->regs[1],  rs5c->regs[2],  rs5c->regs[3],
148 		rs5c->regs[4],  rs5c->regs[5],  rs5c->regs[6],  rs5c->regs[7],
149 		rs5c->regs[8],  rs5c->regs[9],  rs5c->regs[10], rs5c->regs[11],
150 		rs5c->regs[12], rs5c->regs[13], rs5c->regs[14], rs5c->regs[15]);
151 
152 	return 0;
153 }
154 
155 static unsigned rs5c_reg2hr(struct rs5c372 *rs5c, unsigned reg)
156 {
157 	unsigned	hour;
158 
159 	if (rs5c->time24)
160 		return bcd2bin(reg & 0x3f);
161 
162 	hour = bcd2bin(reg & 0x1f);
163 	if (hour == 12)
164 		hour = 0;
165 	if (reg & 0x20)
166 		hour += 12;
167 	return hour;
168 }
169 
170 static unsigned rs5c_hr2reg(struct rs5c372 *rs5c, unsigned hour)
171 {
172 	if (rs5c->time24)
173 		return bin2bcd(hour);
174 
175 	if (hour > 12)
176 		return 0x20 | bin2bcd(hour - 12);
177 	if (hour == 12)
178 		return 0x20 | bin2bcd(12);
179 	if (hour == 0)
180 		return bin2bcd(12);
181 	return bin2bcd(hour);
182 }
183 
184 static int rs5c372_get_datetime(struct i2c_client *client, struct rtc_time *tm)
185 {
186 	struct rs5c372	*rs5c = i2c_get_clientdata(client);
187 	int		status = rs5c_get_regs(rs5c);
188 
189 	if (status < 0)
190 		return status;
191 
192 	tm->tm_sec = bcd2bin(rs5c->regs[RS5C372_REG_SECS] & 0x7f);
193 	tm->tm_min = bcd2bin(rs5c->regs[RS5C372_REG_MINS] & 0x7f);
194 	tm->tm_hour = rs5c_reg2hr(rs5c, rs5c->regs[RS5C372_REG_HOURS]);
195 
196 	tm->tm_wday = bcd2bin(rs5c->regs[RS5C372_REG_WDAY] & 0x07);
197 	tm->tm_mday = bcd2bin(rs5c->regs[RS5C372_REG_DAY] & 0x3f);
198 
199 	/* tm->tm_mon is zero-based */
200 	tm->tm_mon = bcd2bin(rs5c->regs[RS5C372_REG_MONTH] & 0x1f) - 1;
201 
202 	/* year is 1900 + tm->tm_year */
203 	tm->tm_year = bcd2bin(rs5c->regs[RS5C372_REG_YEAR]) + 100;
204 
205 	dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
206 		"mday=%d, mon=%d, year=%d, wday=%d\n",
207 		__func__,
208 		tm->tm_sec, tm->tm_min, tm->tm_hour,
209 		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
210 
211 	/* rtc might need initialization */
212 	return rtc_valid_tm(tm);
213 }
214 
215 static int rs5c372_set_datetime(struct i2c_client *client, struct rtc_time *tm)
216 {
217 	struct rs5c372	*rs5c = i2c_get_clientdata(client);
218 	unsigned char	buf[7];
219 	int		addr;
220 
221 	dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d "
222 		"mday=%d, mon=%d, year=%d, wday=%d\n",
223 		__func__,
224 		tm->tm_sec, tm->tm_min, tm->tm_hour,
225 		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
226 
227 	addr   = RS5C_ADDR(RS5C372_REG_SECS);
228 	buf[0] = bin2bcd(tm->tm_sec);
229 	buf[1] = bin2bcd(tm->tm_min);
230 	buf[2] = rs5c_hr2reg(rs5c, tm->tm_hour);
231 	buf[3] = bin2bcd(tm->tm_wday);
232 	buf[4] = bin2bcd(tm->tm_mday);
233 	buf[5] = bin2bcd(tm->tm_mon + 1);
234 	buf[6] = bin2bcd(tm->tm_year - 100);
235 
236 	if (i2c_smbus_write_i2c_block_data(client, addr, sizeof(buf), buf) < 0) {
237 		dev_err(&client->dev, "%s: write error\n", __func__);
238 		return -EIO;
239 	}
240 
241 	return 0;
242 }
243 
244 #if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
245 #define	NEED_TRIM
246 #endif
247 
248 #if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE)
249 #define	NEED_TRIM
250 #endif
251 
252 #ifdef	NEED_TRIM
253 static int rs5c372_get_trim(struct i2c_client *client, int *osc, int *trim)
254 {
255 	struct rs5c372 *rs5c372 = i2c_get_clientdata(client);
256 	u8 tmp = rs5c372->regs[RS5C372_REG_TRIM];
257 
258 	if (osc)
259 		*osc = (tmp & RS5C372_TRIM_XSL) ? 32000 : 32768;
260 
261 	if (trim) {
262 		dev_dbg(&client->dev, "%s: raw trim=%x\n", __func__, tmp);
263 		tmp &= RS5C372_TRIM_MASK;
264 		if (tmp & 0x3e) {
265 			int t = tmp & 0x3f;
266 
267 			if (tmp & 0x40)
268 				t = (~t | (s8)0xc0) + 1;
269 			else
270 				t = t - 1;
271 
272 			tmp = t * 2;
273 		} else
274 			tmp = 0;
275 		*trim = tmp;
276 	}
277 
278 	return 0;
279 }
280 #endif
281 
282 static int rs5c372_rtc_read_time(struct device *dev, struct rtc_time *tm)
283 {
284 	return rs5c372_get_datetime(to_i2c_client(dev), tm);
285 }
286 
287 static int rs5c372_rtc_set_time(struct device *dev, struct rtc_time *tm)
288 {
289 	return rs5c372_set_datetime(to_i2c_client(dev), tm);
290 }
291 
292 
293 static int rs5c_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
294 {
295 	struct i2c_client	*client = to_i2c_client(dev);
296 	struct rs5c372		*rs5c = i2c_get_clientdata(client);
297 	unsigned char		buf;
298 	int			status, addr;
299 
300 	buf = rs5c->regs[RS5C_REG_CTRL1];
301 
302 	if (!rs5c->has_irq)
303 		return -EINVAL;
304 
305 	status = rs5c_get_regs(rs5c);
306 	if (status < 0)
307 		return status;
308 
309 	addr = RS5C_ADDR(RS5C_REG_CTRL1);
310 	if (enabled)
311 		buf |= RS5C_CTRL1_AALE;
312 	else
313 		buf &= ~RS5C_CTRL1_AALE;
314 
315 	if (i2c_smbus_write_byte_data(client, addr, buf) < 0) {
316 		dev_warn(dev, "can't update alarm\n");
317 		status = -EIO;
318 	} else
319 		rs5c->regs[RS5C_REG_CTRL1] = buf;
320 
321 	return status;
322 }
323 
324 
325 /* NOTE:  Since RTC_WKALM_{RD,SET} were originally defined for EFI,
326  * which only exposes a polled programming interface; and since
327  * these calls map directly to those EFI requests; we don't demand
328  * we have an IRQ for this chip when we go through this API.
329  *
330  * The older x86_pc derived RTC_ALM_{READ,SET} calls require irqs
331  * though, managed through RTC_AIE_{ON,OFF} requests.
332  */
333 
334 static int rs5c_read_alarm(struct device *dev, struct rtc_wkalrm *t)
335 {
336 	struct i2c_client	*client = to_i2c_client(dev);
337 	struct rs5c372		*rs5c = i2c_get_clientdata(client);
338 	int			status;
339 
340 	status = rs5c_get_regs(rs5c);
341 	if (status < 0)
342 		return status;
343 
344 	/* report alarm time */
345 	t->time.tm_sec = 0;
346 	t->time.tm_min = bcd2bin(rs5c->regs[RS5C_REG_ALARM_A_MIN] & 0x7f);
347 	t->time.tm_hour = rs5c_reg2hr(rs5c, rs5c->regs[RS5C_REG_ALARM_A_HOURS]);
348 	t->time.tm_mday = -1;
349 	t->time.tm_mon = -1;
350 	t->time.tm_year = -1;
351 	t->time.tm_wday = -1;
352 	t->time.tm_yday = -1;
353 	t->time.tm_isdst = -1;
354 
355 	/* ... and status */
356 	t->enabled = !!(rs5c->regs[RS5C_REG_CTRL1] & RS5C_CTRL1_AALE);
357 	t->pending = !!(rs5c->regs[RS5C_REG_CTRL2] & RS5C_CTRL2_AAFG);
358 
359 	return 0;
360 }
361 
362 static int rs5c_set_alarm(struct device *dev, struct rtc_wkalrm *t)
363 {
364 	struct i2c_client	*client = to_i2c_client(dev);
365 	struct rs5c372		*rs5c = i2c_get_clientdata(client);
366 	int			status, addr, i;
367 	unsigned char		buf[3];
368 
369 	/* only handle up to 24 hours in the future, like RTC_ALM_SET */
370 	if (t->time.tm_mday != -1
371 			|| t->time.tm_mon != -1
372 			|| t->time.tm_year != -1)
373 		return -EINVAL;
374 
375 	/* REVISIT: round up tm_sec */
376 
377 	/* if needed, disable irq (clears pending status) */
378 	status = rs5c_get_regs(rs5c);
379 	if (status < 0)
380 		return status;
381 	if (rs5c->regs[RS5C_REG_CTRL1] & RS5C_CTRL1_AALE) {
382 		addr = RS5C_ADDR(RS5C_REG_CTRL1);
383 		buf[0] = rs5c->regs[RS5C_REG_CTRL1] & ~RS5C_CTRL1_AALE;
384 		if (i2c_smbus_write_byte_data(client, addr, buf[0]) < 0) {
385 			dev_dbg(dev, "can't disable alarm\n");
386 			return -EIO;
387 		}
388 		rs5c->regs[RS5C_REG_CTRL1] = buf[0];
389 	}
390 
391 	/* set alarm */
392 	buf[0] = bin2bcd(t->time.tm_min);
393 	buf[1] = rs5c_hr2reg(rs5c, t->time.tm_hour);
394 	buf[2] = 0x7f;	/* any/all days */
395 
396 	for (i = 0; i < sizeof(buf); i++) {
397 		addr = RS5C_ADDR(RS5C_REG_ALARM_A_MIN + i);
398 		if (i2c_smbus_write_byte_data(client, addr, buf[i]) < 0) {
399 			dev_dbg(dev, "can't set alarm time\n");
400 			return -EIO;
401 		}
402 	}
403 
404 	/* ... and maybe enable its irq */
405 	if (t->enabled) {
406 		addr = RS5C_ADDR(RS5C_REG_CTRL1);
407 		buf[0] = rs5c->regs[RS5C_REG_CTRL1] | RS5C_CTRL1_AALE;
408 		if (i2c_smbus_write_byte_data(client, addr, buf[0]) < 0)
409 			dev_warn(dev, "can't enable alarm\n");
410 		rs5c->regs[RS5C_REG_CTRL1] = buf[0];
411 	}
412 
413 	return 0;
414 }
415 
416 #if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
417 
418 static int rs5c372_rtc_proc(struct device *dev, struct seq_file *seq)
419 {
420 	int err, osc, trim;
421 
422 	err = rs5c372_get_trim(to_i2c_client(dev), &osc, &trim);
423 	if (err == 0) {
424 		seq_printf(seq, "crystal\t\t: %d.%03d KHz\n",
425 				osc / 1000, osc % 1000);
426 		seq_printf(seq, "trim\t\t: %d\n", trim);
427 	}
428 
429 	return 0;
430 }
431 
432 #else
433 #define	rs5c372_rtc_proc	NULL
434 #endif
435 
436 static const struct rtc_class_ops rs5c372_rtc_ops = {
437 	.proc		= rs5c372_rtc_proc,
438 	.read_time	= rs5c372_rtc_read_time,
439 	.set_time	= rs5c372_rtc_set_time,
440 	.read_alarm	= rs5c_read_alarm,
441 	.set_alarm	= rs5c_set_alarm,
442 	.alarm_irq_enable = rs5c_rtc_alarm_irq_enable,
443 };
444 
445 #if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE)
446 
447 static ssize_t rs5c372_sysfs_show_trim(struct device *dev,
448 				struct device_attribute *attr, char *buf)
449 {
450 	int err, trim;
451 
452 	err = rs5c372_get_trim(to_i2c_client(dev), NULL, &trim);
453 	if (err)
454 		return err;
455 
456 	return sprintf(buf, "%d\n", trim);
457 }
458 static DEVICE_ATTR(trim, S_IRUGO, rs5c372_sysfs_show_trim, NULL);
459 
460 static ssize_t rs5c372_sysfs_show_osc(struct device *dev,
461 				struct device_attribute *attr, char *buf)
462 {
463 	int err, osc;
464 
465 	err = rs5c372_get_trim(to_i2c_client(dev), &osc, NULL);
466 	if (err)
467 		return err;
468 
469 	return sprintf(buf, "%d.%03d KHz\n", osc / 1000, osc % 1000);
470 }
471 static DEVICE_ATTR(osc, S_IRUGO, rs5c372_sysfs_show_osc, NULL);
472 
473 static int rs5c_sysfs_register(struct device *dev)
474 {
475 	int err;
476 
477 	err = device_create_file(dev, &dev_attr_trim);
478 	if (err)
479 		return err;
480 	err = device_create_file(dev, &dev_attr_osc);
481 	if (err)
482 		device_remove_file(dev, &dev_attr_trim);
483 
484 	return err;
485 }
486 
487 static void rs5c_sysfs_unregister(struct device *dev)
488 {
489 	device_remove_file(dev, &dev_attr_trim);
490 	device_remove_file(dev, &dev_attr_osc);
491 }
492 
493 #else
494 static int rs5c_sysfs_register(struct device *dev)
495 {
496 	return 0;
497 }
498 
499 static void rs5c_sysfs_unregister(struct device *dev)
500 {
501 	/* nothing */
502 }
503 #endif	/* SYSFS */
504 
505 static struct i2c_driver rs5c372_driver;
506 
507 static int rs5c_oscillator_setup(struct rs5c372 *rs5c372)
508 {
509 	unsigned char buf[2];
510 	int addr, i, ret = 0;
511 
512 	if (rs5c372->type == rtc_r2025sd) {
513 		if (!(rs5c372->regs[RS5C_REG_CTRL2] & R2025_CTRL2_XST))
514 			return ret;
515 		rs5c372->regs[RS5C_REG_CTRL2] &= ~R2025_CTRL2_XST;
516 	} else {
517 		if (!(rs5c372->regs[RS5C_REG_CTRL2] & RS5C_CTRL2_XSTP))
518 			return ret;
519 		rs5c372->regs[RS5C_REG_CTRL2] &= ~RS5C_CTRL2_XSTP;
520 	}
521 
522 	addr   = RS5C_ADDR(RS5C_REG_CTRL1);
523 	buf[0] = rs5c372->regs[RS5C_REG_CTRL1];
524 	buf[1] = rs5c372->regs[RS5C_REG_CTRL2];
525 
526 	/* use 24hr mode */
527 	switch (rs5c372->type) {
528 	case rtc_rs5c372a:
529 	case rtc_rs5c372b:
530 		buf[1] |= RS5C372_CTRL2_24;
531 		rs5c372->time24 = 1;
532 		break;
533 	case rtc_r2025sd:
534 	case rtc_r2221tl:
535 	case rtc_rv5c386:
536 	case rtc_rv5c387a:
537 		buf[0] |= RV5C387_CTRL1_24;
538 		rs5c372->time24 = 1;
539 		break;
540 	default:
541 		/* impossible */
542 		break;
543 	}
544 
545 	for (i = 0; i < sizeof(buf); i++) {
546 		addr = RS5C_ADDR(RS5C_REG_CTRL1 + i);
547 		ret = i2c_smbus_write_byte_data(rs5c372->client, addr, buf[i]);
548 		if (unlikely(ret < 0))
549 			return ret;
550 	}
551 
552 	rs5c372->regs[RS5C_REG_CTRL1] = buf[0];
553 	rs5c372->regs[RS5C_REG_CTRL2] = buf[1];
554 
555 	return 0;
556 }
557 
558 static int rs5c372_probe(struct i2c_client *client,
559 			 const struct i2c_device_id *id)
560 {
561 	int err = 0;
562 	int smbus_mode = 0;
563 	struct rs5c372 *rs5c372;
564 	struct rtc_time tm;
565 
566 	dev_dbg(&client->dev, "%s\n", __func__);
567 
568 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
569 			I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK)) {
570 		/*
571 		 * If we don't have any master mode adapter, try breaking
572 		 * it down in to the barest of capabilities.
573 		 */
574 		if (i2c_check_functionality(client->adapter,
575 				I2C_FUNC_SMBUS_BYTE_DATA |
576 				I2C_FUNC_SMBUS_I2C_BLOCK))
577 			smbus_mode = 1;
578 		else {
579 			/* Still no good, give up */
580 			err = -ENODEV;
581 			goto exit;
582 		}
583 	}
584 
585 	rs5c372 = devm_kzalloc(&client->dev, sizeof(struct rs5c372),
586 				GFP_KERNEL);
587 	if (!rs5c372) {
588 		err = -ENOMEM;
589 		goto exit;
590 	}
591 
592 	rs5c372->client = client;
593 	i2c_set_clientdata(client, rs5c372);
594 	rs5c372->type = id->driver_data;
595 
596 	/* we read registers 0x0f then 0x00-0x0f; skip the first one */
597 	rs5c372->regs = &rs5c372->buf[1];
598 	rs5c372->smbus = smbus_mode;
599 
600 	err = rs5c_get_regs(rs5c372);
601 	if (err < 0)
602 		goto exit;
603 
604 	/* clock may be set for am/pm or 24 hr time */
605 	switch (rs5c372->type) {
606 	case rtc_rs5c372a:
607 	case rtc_rs5c372b:
608 		/* alarm uses ALARM_A; and nINTRA on 372a, nINTR on 372b.
609 		 * so does periodic irq, except some 327a modes.
610 		 */
611 		if (rs5c372->regs[RS5C_REG_CTRL2] & RS5C372_CTRL2_24)
612 			rs5c372->time24 = 1;
613 		break;
614 	case rtc_r2025sd:
615 	case rtc_r2221tl:
616 	case rtc_rv5c386:
617 	case rtc_rv5c387a:
618 		if (rs5c372->regs[RS5C_REG_CTRL1] & RV5C387_CTRL1_24)
619 			rs5c372->time24 = 1;
620 		/* alarm uses ALARM_W; and nINTRB for alarm and periodic
621 		 * irq, on both 386 and 387
622 		 */
623 		break;
624 	default:
625 		dev_err(&client->dev, "unknown RTC type\n");
626 		goto exit;
627 	}
628 
629 	/* if the oscillator lost power and no other software (like
630 	 * the bootloader) set it up, do it here.
631 	 *
632 	 * The R2025S/D does this a little differently than the other
633 	 * parts, so we special case that..
634 	 */
635 	err = rs5c_oscillator_setup(rs5c372);
636 	if (unlikely(err < 0)) {
637 		dev_err(&client->dev, "setup error\n");
638 		goto exit;
639 	}
640 
641 	if (rs5c372_get_datetime(client, &tm) < 0)
642 		dev_warn(&client->dev, "clock needs to be set\n");
643 
644 	dev_info(&client->dev, "%s found, %s, driver version " DRV_VERSION "\n",
645 			({ char *s; switch (rs5c372->type) {
646 			case rtc_r2025sd:	s = "r2025sd"; break;
647 			case rtc_r2221tl:	s = "r2221tl"; break;
648 			case rtc_rs5c372a:	s = "rs5c372a"; break;
649 			case rtc_rs5c372b:	s = "rs5c372b"; break;
650 			case rtc_rv5c386:	s = "rv5c386"; break;
651 			case rtc_rv5c387a:	s = "rv5c387a"; break;
652 			default:		s = "chip"; break;
653 			}; s;}),
654 			rs5c372->time24 ? "24hr" : "am/pm"
655 			);
656 
657 	/* REVISIT use client->irq to register alarm irq ... */
658 	rs5c372->rtc = devm_rtc_device_register(&client->dev,
659 					rs5c372_driver.driver.name,
660 					&rs5c372_rtc_ops, THIS_MODULE);
661 
662 	if (IS_ERR(rs5c372->rtc)) {
663 		err = PTR_ERR(rs5c372->rtc);
664 		goto exit;
665 	}
666 
667 	err = rs5c_sysfs_register(&client->dev);
668 	if (err)
669 		goto exit;
670 
671 	return 0;
672 
673 exit:
674 	return err;
675 }
676 
677 static int rs5c372_remove(struct i2c_client *client)
678 {
679 	rs5c_sysfs_unregister(&client->dev);
680 	return 0;
681 }
682 
683 static struct i2c_driver rs5c372_driver = {
684 	.driver		= {
685 		.name	= "rtc-rs5c372",
686 	},
687 	.probe		= rs5c372_probe,
688 	.remove		= rs5c372_remove,
689 	.id_table	= rs5c372_id,
690 };
691 
692 module_i2c_driver(rs5c372_driver);
693 
694 MODULE_AUTHOR(
695 		"Pavel Mironchik <pmironchik@optifacio.net>, "
696 		"Alessandro Zummo <a.zummo@towertech.it>, "
697 		"Paul Mundt <lethal@linux-sh.org>");
698 MODULE_DESCRIPTION("Ricoh RS5C372 RTC driver");
699 MODULE_LICENSE("GPL");
700 MODULE_VERSION(DRV_VERSION);
701