xref: /linux/drivers/rtc/rtc-rs5c372.c (revision 492c826b9facefa84995f4dea917e301b5ee0884)
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 
18 #define DRV_VERSION "0.6"
19 
20 
21 /*
22  * Ricoh has a family of I2C based RTCs, which differ only slightly from
23  * each other.  Differences center on pinout (e.g. how many interrupts,
24  * output clock, etc) and how the control registers are used.  The '372
25  * is significant only because that's the one this driver first supported.
26  */
27 #define RS5C372_REG_SECS	0
28 #define RS5C372_REG_MINS	1
29 #define RS5C372_REG_HOURS	2
30 #define RS5C372_REG_WDAY	3
31 #define RS5C372_REG_DAY		4
32 #define RS5C372_REG_MONTH	5
33 #define RS5C372_REG_YEAR	6
34 #define RS5C372_REG_TRIM	7
35 #	define RS5C372_TRIM_XSL		0x80
36 #	define RS5C372_TRIM_MASK	0x7F
37 
38 #define RS5C_REG_ALARM_A_MIN	8			/* or ALARM_W */
39 #define RS5C_REG_ALARM_A_HOURS	9
40 #define RS5C_REG_ALARM_A_WDAY	10
41 
42 #define RS5C_REG_ALARM_B_MIN	11			/* or ALARM_D */
43 #define RS5C_REG_ALARM_B_HOURS	12
44 #define RS5C_REG_ALARM_B_WDAY	13			/* (ALARM_B only) */
45 
46 #define RS5C_REG_CTRL1		14
47 #	define RS5C_CTRL1_AALE		(1 << 7)	/* or WALE */
48 #	define RS5C_CTRL1_BALE		(1 << 6)	/* or DALE */
49 #	define RV5C387_CTRL1_24		(1 << 5)
50 #	define RS5C372A_CTRL1_SL1	(1 << 5)
51 #	define RS5C_CTRL1_CT_MASK	(7 << 0)
52 #	define RS5C_CTRL1_CT0		(0 << 0)	/* no periodic irq */
53 #	define RS5C_CTRL1_CT4		(4 << 0)	/* 1 Hz level irq */
54 #define RS5C_REG_CTRL2		15
55 #	define RS5C372_CTRL2_24		(1 << 5)
56 #	define R2025_CTRL2_XST		(1 << 5)
57 #	define RS5C_CTRL2_XSTP		(1 << 4)	/* only if !R2025S/D */
58 #	define RS5C_CTRL2_CTFG		(1 << 2)
59 #	define RS5C_CTRL2_AAFG		(1 << 1)	/* or WAFG */
60 #	define RS5C_CTRL2_BAFG		(1 << 0)	/* or DAFG */
61 
62 
63 /* to read (style 1) or write registers starting at R */
64 #define RS5C_ADDR(R)		(((R) << 4) | 0)
65 
66 
67 enum rtc_type {
68 	rtc_undef = 0,
69 	rtc_r2025sd,
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 	{ "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 		{ client->addr, I2C_M_RD, sizeof rs5c->buf, rs5c->buf },
107 	};
108 
109 	/* This implements the third reading method from the datasheet, using
110 	 * an internal address that's reset after each transaction (by STOP)
111 	 * to 0x0f ... so we read extra registers, and skip the first one.
112 	 *
113 	 * The first method doesn't work with the iop3xx adapter driver, on at
114 	 * least 80219 chips; this works around that bug.
115 	 *
116 	 * The third method on the other hand doesn't work for the SMBus-only
117 	 * configurations, so we use the the first method there, stripping off
118 	 * the extra register in the process.
119 	 */
120 	if (rs5c->smbus) {
121 		int addr = RS5C_ADDR(RS5C372_REG_SECS);
122 		int size = sizeof(rs5c->buf) - 1;
123 
124 		if (i2c_smbus_read_i2c_block_data(client, addr, size,
125 						  rs5c->buf + 1) != size) {
126 			dev_warn(&client->dev, "can't read registers\n");
127 			return -EIO;
128 		}
129 	} else {
130 		if ((i2c_transfer(client->adapter, msgs, 1)) != 1) {
131 			dev_warn(&client->dev, "can't read registers\n");
132 			return -EIO;
133 		}
134 	}
135 
136 	dev_dbg(&client->dev,
137 		"%02x %02x %02x (%02x) %02x %02x %02x (%02x), "
138 		"%02x %02x %02x, %02x %02x %02x; %02x %02x\n",
139 		rs5c->regs[0],  rs5c->regs[1],  rs5c->regs[2],  rs5c->regs[3],
140 		rs5c->regs[4],  rs5c->regs[5],  rs5c->regs[6],  rs5c->regs[7],
141 		rs5c->regs[8],  rs5c->regs[9],  rs5c->regs[10], rs5c->regs[11],
142 		rs5c->regs[12], rs5c->regs[13], rs5c->regs[14], rs5c->regs[15]);
143 
144 	return 0;
145 }
146 
147 static unsigned rs5c_reg2hr(struct rs5c372 *rs5c, unsigned reg)
148 {
149 	unsigned	hour;
150 
151 	if (rs5c->time24)
152 		return bcd2bin(reg & 0x3f);
153 
154 	hour = bcd2bin(reg & 0x1f);
155 	if (hour == 12)
156 		hour = 0;
157 	if (reg & 0x20)
158 		hour += 12;
159 	return hour;
160 }
161 
162 static unsigned rs5c_hr2reg(struct rs5c372 *rs5c, unsigned hour)
163 {
164 	if (rs5c->time24)
165 		return bin2bcd(hour);
166 
167 	if (hour > 12)
168 		return 0x20 | bin2bcd(hour - 12);
169 	if (hour == 12)
170 		return 0x20 | bin2bcd(12);
171 	if (hour == 0)
172 		return bin2bcd(12);
173 	return bin2bcd(hour);
174 }
175 
176 static int rs5c372_get_datetime(struct i2c_client *client, struct rtc_time *tm)
177 {
178 	struct rs5c372	*rs5c = i2c_get_clientdata(client);
179 	int		status = rs5c_get_regs(rs5c);
180 
181 	if (status < 0)
182 		return status;
183 
184 	tm->tm_sec = bcd2bin(rs5c->regs[RS5C372_REG_SECS] & 0x7f);
185 	tm->tm_min = bcd2bin(rs5c->regs[RS5C372_REG_MINS] & 0x7f);
186 	tm->tm_hour = rs5c_reg2hr(rs5c, rs5c->regs[RS5C372_REG_HOURS]);
187 
188 	tm->tm_wday = bcd2bin(rs5c->regs[RS5C372_REG_WDAY] & 0x07);
189 	tm->tm_mday = bcd2bin(rs5c->regs[RS5C372_REG_DAY] & 0x3f);
190 
191 	/* tm->tm_mon is zero-based */
192 	tm->tm_mon = bcd2bin(rs5c->regs[RS5C372_REG_MONTH] & 0x1f) - 1;
193 
194 	/* year is 1900 + tm->tm_year */
195 	tm->tm_year = bcd2bin(rs5c->regs[RS5C372_REG_YEAR]) + 100;
196 
197 	dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
198 		"mday=%d, mon=%d, year=%d, wday=%d\n",
199 		__func__,
200 		tm->tm_sec, tm->tm_min, tm->tm_hour,
201 		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
202 
203 	/* rtc might need initialization */
204 	return rtc_valid_tm(tm);
205 }
206 
207 static int rs5c372_set_datetime(struct i2c_client *client, struct rtc_time *tm)
208 {
209 	struct rs5c372	*rs5c = i2c_get_clientdata(client);
210 	unsigned char	buf[7];
211 	int		addr;
212 
213 	dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d "
214 		"mday=%d, mon=%d, year=%d, wday=%d\n",
215 		__func__,
216 		tm->tm_sec, tm->tm_min, tm->tm_hour,
217 		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
218 
219 	addr   = RS5C_ADDR(RS5C372_REG_SECS);
220 	buf[0] = bin2bcd(tm->tm_sec);
221 	buf[1] = bin2bcd(tm->tm_min);
222 	buf[2] = rs5c_hr2reg(rs5c, tm->tm_hour);
223 	buf[3] = bin2bcd(tm->tm_wday);
224 	buf[4] = bin2bcd(tm->tm_mday);
225 	buf[5] = bin2bcd(tm->tm_mon + 1);
226 	buf[6] = bin2bcd(tm->tm_year - 100);
227 
228 	if (i2c_smbus_write_i2c_block_data(client, addr, sizeof(buf), buf) < 0) {
229 		dev_err(&client->dev, "%s: write error\n", __func__);
230 		return -EIO;
231 	}
232 
233 	return 0;
234 }
235 
236 #if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
237 #define	NEED_TRIM
238 #endif
239 
240 #if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE)
241 #define	NEED_TRIM
242 #endif
243 
244 #ifdef	NEED_TRIM
245 static int rs5c372_get_trim(struct i2c_client *client, int *osc, int *trim)
246 {
247 	struct rs5c372 *rs5c372 = i2c_get_clientdata(client);
248 	u8 tmp = rs5c372->regs[RS5C372_REG_TRIM];
249 
250 	if (osc)
251 		*osc = (tmp & RS5C372_TRIM_XSL) ? 32000 : 32768;
252 
253 	if (trim) {
254 		dev_dbg(&client->dev, "%s: raw trim=%x\n", __func__, tmp);
255 		tmp &= RS5C372_TRIM_MASK;
256 		if (tmp & 0x3e) {
257 			int t = tmp & 0x3f;
258 
259 			if (tmp & 0x40)
260 				t = (~t | (s8)0xc0) + 1;
261 			else
262 				t = t - 1;
263 
264 			tmp = t * 2;
265 		} else
266 			tmp = 0;
267 		*trim = tmp;
268 	}
269 
270 	return 0;
271 }
272 #endif
273 
274 static int rs5c372_rtc_read_time(struct device *dev, struct rtc_time *tm)
275 {
276 	return rs5c372_get_datetime(to_i2c_client(dev), tm);
277 }
278 
279 static int rs5c372_rtc_set_time(struct device *dev, struct rtc_time *tm)
280 {
281 	return rs5c372_set_datetime(to_i2c_client(dev), tm);
282 }
283 
284 
285 static int rs5c_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
286 {
287 	struct i2c_client	*client = to_i2c_client(dev);
288 	struct rs5c372		*rs5c = i2c_get_clientdata(client);
289 	unsigned char		buf;
290 	int			status, addr;
291 
292 	buf = rs5c->regs[RS5C_REG_CTRL1];
293 
294 	if (!rs5c->has_irq)
295 		return -EINVAL;
296 
297 	status = rs5c_get_regs(rs5c);
298 	if (status < 0)
299 		return status;
300 
301 	addr = RS5C_ADDR(RS5C_REG_CTRL1);
302 	if (enabled)
303 		buf |= RS5C_CTRL1_AALE;
304 	else
305 		buf &= ~RS5C_CTRL1_AALE;
306 
307 	if (i2c_smbus_write_byte_data(client, addr, buf) < 0) {
308 		printk(KERN_WARNING "%s: can't update alarm\n",
309 			rs5c->rtc->name);
310 		status = -EIO;
311 	} else
312 		rs5c->regs[RS5C_REG_CTRL1] = buf;
313 
314 	return status;
315 }
316 
317 
318 /* NOTE:  Since RTC_WKALM_{RD,SET} were originally defined for EFI,
319  * which only exposes a polled programming interface; and since
320  * these calls map directly to those EFI requests; we don't demand
321  * we have an IRQ for this chip when we go through this API.
322  *
323  * The older x86_pc derived RTC_ALM_{READ,SET} calls require irqs
324  * though, managed through RTC_AIE_{ON,OFF} requests.
325  */
326 
327 static int rs5c_read_alarm(struct device *dev, struct rtc_wkalrm *t)
328 {
329 	struct i2c_client	*client = to_i2c_client(dev);
330 	struct rs5c372		*rs5c = i2c_get_clientdata(client);
331 	int			status;
332 
333 	status = rs5c_get_regs(rs5c);
334 	if (status < 0)
335 		return status;
336 
337 	/* report alarm time */
338 	t->time.tm_sec = 0;
339 	t->time.tm_min = bcd2bin(rs5c->regs[RS5C_REG_ALARM_A_MIN] & 0x7f);
340 	t->time.tm_hour = rs5c_reg2hr(rs5c, rs5c->regs[RS5C_REG_ALARM_A_HOURS]);
341 	t->time.tm_mday = -1;
342 	t->time.tm_mon = -1;
343 	t->time.tm_year = -1;
344 	t->time.tm_wday = -1;
345 	t->time.tm_yday = -1;
346 	t->time.tm_isdst = -1;
347 
348 	/* ... and status */
349 	t->enabled = !!(rs5c->regs[RS5C_REG_CTRL1] & RS5C_CTRL1_AALE);
350 	t->pending = !!(rs5c->regs[RS5C_REG_CTRL2] & RS5C_CTRL2_AAFG);
351 
352 	return 0;
353 }
354 
355 static int rs5c_set_alarm(struct device *dev, struct rtc_wkalrm *t)
356 {
357 	struct i2c_client	*client = to_i2c_client(dev);
358 	struct rs5c372		*rs5c = i2c_get_clientdata(client);
359 	int			status, addr, i;
360 	unsigned char		buf[3];
361 
362 	/* only handle up to 24 hours in the future, like RTC_ALM_SET */
363 	if (t->time.tm_mday != -1
364 			|| t->time.tm_mon != -1
365 			|| t->time.tm_year != -1)
366 		return -EINVAL;
367 
368 	/* REVISIT: round up tm_sec */
369 
370 	/* if needed, disable irq (clears pending status) */
371 	status = rs5c_get_regs(rs5c);
372 	if (status < 0)
373 		return status;
374 	if (rs5c->regs[RS5C_REG_CTRL1] & RS5C_CTRL1_AALE) {
375 		addr = RS5C_ADDR(RS5C_REG_CTRL1);
376 		buf[0] = rs5c->regs[RS5C_REG_CTRL1] & ~RS5C_CTRL1_AALE;
377 		if (i2c_smbus_write_byte_data(client, addr, buf[0]) < 0) {
378 			pr_debug("%s: can't disable alarm\n", rs5c->rtc->name);
379 			return -EIO;
380 		}
381 		rs5c->regs[RS5C_REG_CTRL1] = buf[0];
382 	}
383 
384 	/* set alarm */
385 	buf[0] = bin2bcd(t->time.tm_min);
386 	buf[1] = rs5c_hr2reg(rs5c, t->time.tm_hour);
387 	buf[2] = 0x7f;	/* any/all days */
388 
389 	for (i = 0; i < sizeof(buf); i++) {
390 		addr = RS5C_ADDR(RS5C_REG_ALARM_A_MIN + i);
391 		if (i2c_smbus_write_byte_data(client, addr, buf[i]) < 0) {
392 			pr_debug("%s: can't set alarm time\n", rs5c->rtc->name);
393 			return -EIO;
394 		}
395 	}
396 
397 	/* ... and maybe enable its irq */
398 	if (t->enabled) {
399 		addr = RS5C_ADDR(RS5C_REG_CTRL1);
400 		buf[0] = rs5c->regs[RS5C_REG_CTRL1] | RS5C_CTRL1_AALE;
401 		if (i2c_smbus_write_byte_data(client, addr, buf[0]) < 0)
402 			printk(KERN_WARNING "%s: can't enable alarm\n",
403 				rs5c->rtc->name);
404 		rs5c->regs[RS5C_REG_CTRL1] = buf[0];
405 	}
406 
407 	return 0;
408 }
409 
410 #if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
411 
412 static int rs5c372_rtc_proc(struct device *dev, struct seq_file *seq)
413 {
414 	int err, osc, trim;
415 
416 	err = rs5c372_get_trim(to_i2c_client(dev), &osc, &trim);
417 	if (err == 0) {
418 		seq_printf(seq, "crystal\t\t: %d.%03d KHz\n",
419 				osc / 1000, osc % 1000);
420 		seq_printf(seq, "trim\t\t: %d\n", trim);
421 	}
422 
423 	return 0;
424 }
425 
426 #else
427 #define	rs5c372_rtc_proc	NULL
428 #endif
429 
430 static const struct rtc_class_ops rs5c372_rtc_ops = {
431 	.proc		= rs5c372_rtc_proc,
432 	.read_time	= rs5c372_rtc_read_time,
433 	.set_time	= rs5c372_rtc_set_time,
434 	.read_alarm	= rs5c_read_alarm,
435 	.set_alarm	= rs5c_set_alarm,
436 	.alarm_irq_enable = rs5c_rtc_alarm_irq_enable,
437 };
438 
439 #if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE)
440 
441 static ssize_t rs5c372_sysfs_show_trim(struct device *dev,
442 				struct device_attribute *attr, char *buf)
443 {
444 	int err, trim;
445 
446 	err = rs5c372_get_trim(to_i2c_client(dev), NULL, &trim);
447 	if (err)
448 		return err;
449 
450 	return sprintf(buf, "%d\n", trim);
451 }
452 static DEVICE_ATTR(trim, S_IRUGO, rs5c372_sysfs_show_trim, NULL);
453 
454 static ssize_t rs5c372_sysfs_show_osc(struct device *dev,
455 				struct device_attribute *attr, char *buf)
456 {
457 	int err, osc;
458 
459 	err = rs5c372_get_trim(to_i2c_client(dev), &osc, NULL);
460 	if (err)
461 		return err;
462 
463 	return sprintf(buf, "%d.%03d KHz\n", osc / 1000, osc % 1000);
464 }
465 static DEVICE_ATTR(osc, S_IRUGO, rs5c372_sysfs_show_osc, NULL);
466 
467 static int rs5c_sysfs_register(struct device *dev)
468 {
469 	int err;
470 
471 	err = device_create_file(dev, &dev_attr_trim);
472 	if (err)
473 		return err;
474 	err = device_create_file(dev, &dev_attr_osc);
475 	if (err)
476 		device_remove_file(dev, &dev_attr_trim);
477 
478 	return err;
479 }
480 
481 static void rs5c_sysfs_unregister(struct device *dev)
482 {
483 	device_remove_file(dev, &dev_attr_trim);
484 	device_remove_file(dev, &dev_attr_osc);
485 }
486 
487 #else
488 static int rs5c_sysfs_register(struct device *dev)
489 {
490 	return 0;
491 }
492 
493 static void rs5c_sysfs_unregister(struct device *dev)
494 {
495 	/* nothing */
496 }
497 #endif	/* SYSFS */
498 
499 static struct i2c_driver rs5c372_driver;
500 
501 static int rs5c_oscillator_setup(struct rs5c372 *rs5c372)
502 {
503 	unsigned char buf[2];
504 	int addr, i, ret = 0;
505 
506 	if (rs5c372->type == rtc_r2025sd) {
507 		if (!(rs5c372->regs[RS5C_REG_CTRL2] & R2025_CTRL2_XST))
508 			return ret;
509 		rs5c372->regs[RS5C_REG_CTRL2] &= ~R2025_CTRL2_XST;
510 	} else {
511 		if (!(rs5c372->regs[RS5C_REG_CTRL2] & RS5C_CTRL2_XSTP))
512 			return ret;
513 		rs5c372->regs[RS5C_REG_CTRL2] &= ~RS5C_CTRL2_XSTP;
514 	}
515 
516 	addr   = RS5C_ADDR(RS5C_REG_CTRL1);
517 	buf[0] = rs5c372->regs[RS5C_REG_CTRL1];
518 	buf[1] = rs5c372->regs[RS5C_REG_CTRL2];
519 
520 	/* use 24hr mode */
521 	switch (rs5c372->type) {
522 	case rtc_rs5c372a:
523 	case rtc_rs5c372b:
524 		buf[1] |= RS5C372_CTRL2_24;
525 		rs5c372->time24 = 1;
526 		break;
527 	case rtc_r2025sd:
528 	case rtc_rv5c386:
529 	case rtc_rv5c387a:
530 		buf[0] |= RV5C387_CTRL1_24;
531 		rs5c372->time24 = 1;
532 		break;
533 	default:
534 		/* impossible */
535 		break;
536 	}
537 
538 	for (i = 0; i < sizeof(buf); i++) {
539 		addr = RS5C_ADDR(RS5C_REG_CTRL1 + i);
540 		ret = i2c_smbus_write_byte_data(rs5c372->client, addr, buf[i]);
541 		if (unlikely(ret < 0))
542 			return ret;
543 	}
544 
545 	rs5c372->regs[RS5C_REG_CTRL1] = buf[0];
546 	rs5c372->regs[RS5C_REG_CTRL2] = buf[1];
547 
548 	return 0;
549 }
550 
551 static int rs5c372_probe(struct i2c_client *client,
552 			 const struct i2c_device_id *id)
553 {
554 	int err = 0;
555 	int smbus_mode = 0;
556 	struct rs5c372 *rs5c372;
557 	struct rtc_time tm;
558 
559 	dev_dbg(&client->dev, "%s\n", __func__);
560 
561 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
562 			I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK)) {
563 		/*
564 		 * If we don't have any master mode adapter, try breaking
565 		 * it down in to the barest of capabilities.
566 		 */
567 		if (i2c_check_functionality(client->adapter,
568 				I2C_FUNC_SMBUS_BYTE_DATA |
569 				I2C_FUNC_SMBUS_I2C_BLOCK))
570 			smbus_mode = 1;
571 		else {
572 			/* Still no good, give up */
573 			err = -ENODEV;
574 			goto exit;
575 		}
576 	}
577 
578 	if (!(rs5c372 = kzalloc(sizeof(struct rs5c372), GFP_KERNEL))) {
579 		err = -ENOMEM;
580 		goto exit;
581 	}
582 
583 	rs5c372->client = client;
584 	i2c_set_clientdata(client, rs5c372);
585 	rs5c372->type = id->driver_data;
586 
587 	/* we read registers 0x0f then 0x00-0x0f; skip the first one */
588 	rs5c372->regs = &rs5c372->buf[1];
589 	rs5c372->smbus = smbus_mode;
590 
591 	err = rs5c_get_regs(rs5c372);
592 	if (err < 0)
593 		goto exit_kfree;
594 
595 	/* clock may be set for am/pm or 24 hr time */
596 	switch (rs5c372->type) {
597 	case rtc_rs5c372a:
598 	case rtc_rs5c372b:
599 		/* alarm uses ALARM_A; and nINTRA on 372a, nINTR on 372b.
600 		 * so does periodic irq, except some 327a modes.
601 		 */
602 		if (rs5c372->regs[RS5C_REG_CTRL2] & RS5C372_CTRL2_24)
603 			rs5c372->time24 = 1;
604 		break;
605 	case rtc_r2025sd:
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_kfree;
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_kfree;
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, driver version " DRV_VERSION "\n",
635 			({ char *s; switch (rs5c372->type) {
636 			case rtc_r2025sd:	s = "r2025sd"; break;
637 			case rtc_rs5c372a:	s = "rs5c372a"; break;
638 			case rtc_rs5c372b:	s = "rs5c372b"; break;
639 			case rtc_rv5c386:	s = "rv5c386"; break;
640 			case rtc_rv5c387a:	s = "rv5c387a"; break;
641 			default:		s = "chip"; break;
642 			}; s;}),
643 			rs5c372->time24 ? "24hr" : "am/pm"
644 			);
645 
646 	/* REVISIT use client->irq to register alarm irq ... */
647 
648 	rs5c372->rtc = rtc_device_register(rs5c372_driver.driver.name,
649 				&client->dev, &rs5c372_rtc_ops, THIS_MODULE);
650 
651 	if (IS_ERR(rs5c372->rtc)) {
652 		err = PTR_ERR(rs5c372->rtc);
653 		goto exit_kfree;
654 	}
655 
656 	err = rs5c_sysfs_register(&client->dev);
657 	if (err)
658 		goto exit_devreg;
659 
660 	return 0;
661 
662 exit_devreg:
663 	rtc_device_unregister(rs5c372->rtc);
664 
665 exit_kfree:
666 	kfree(rs5c372);
667 
668 exit:
669 	return err;
670 }
671 
672 static int rs5c372_remove(struct i2c_client *client)
673 {
674 	struct rs5c372 *rs5c372 = i2c_get_clientdata(client);
675 
676 	rtc_device_unregister(rs5c372->rtc);
677 	rs5c_sysfs_unregister(&client->dev);
678 	kfree(rs5c372);
679 	return 0;
680 }
681 
682 static struct i2c_driver rs5c372_driver = {
683 	.driver		= {
684 		.name	= "rtc-rs5c372",
685 	},
686 	.probe		= rs5c372_probe,
687 	.remove		= rs5c372_remove,
688 	.id_table	= rs5c372_id,
689 };
690 
691 static __init int rs5c372_init(void)
692 {
693 	return i2c_add_driver(&rs5c372_driver);
694 }
695 
696 static __exit void rs5c372_exit(void)
697 {
698 	i2c_del_driver(&rs5c372_driver);
699 }
700 
701 module_init(rs5c372_init);
702 module_exit(rs5c372_exit);
703 
704 MODULE_AUTHOR(
705 		"Pavel Mironchik <pmironchik@optifacio.net>, "
706 		"Alessandro Zummo <a.zummo@towertech.it>, "
707 		"Paul Mundt <lethal@linux-sh.org>");
708 MODULE_DESCRIPTION("Ricoh RS5C372 RTC driver");
709 MODULE_LICENSE("GPL");
710 MODULE_VERSION(DRV_VERSION);
711