xref: /openbmc/linux/drivers/rtc/rtc-rs5c372.c (revision 63dc02bd)
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_rs5c372a,
72 	rtc_rs5c372b,
73 	rtc_rv5c386,
74 	rtc_rv5c387a,
75 };
76 
77 static const struct i2c_device_id rs5c372_id[] = {
78 	{ "r2025sd", rtc_r2025sd },
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 /* REVISIT:  this assumes that:
88  *  - we're in the 21st century, so it's safe to ignore the century
89  *    bit for rv5c38[67] (REG_MONTH bit 7);
90  *  - we should use ALARM_A not ALARM_B (may be wrong on some boards)
91  */
92 struct rs5c372 {
93 	struct i2c_client	*client;
94 	struct rtc_device	*rtc;
95 	enum rtc_type		type;
96 	unsigned		time24:1;
97 	unsigned		has_irq:1;
98 	unsigned		smbus:1;
99 	char			buf[17];
100 	char			*regs;
101 };
102 
103 static int rs5c_get_regs(struct rs5c372 *rs5c)
104 {
105 	struct i2c_client	*client = rs5c->client;
106 	struct i2c_msg		msgs[] = {
107 		{ client->addr, I2C_M_RD, sizeof rs5c->buf, rs5c->buf },
108 	};
109 
110 	/* This implements the third reading method from the datasheet, using
111 	 * an internal address that's reset after each transaction (by STOP)
112 	 * to 0x0f ... so we read extra registers, and skip the first one.
113 	 *
114 	 * The first method doesn't work with the iop3xx adapter driver, on at
115 	 * least 80219 chips; this works around that bug.
116 	 *
117 	 * The third method on the other hand doesn't work for the SMBus-only
118 	 * configurations, so we use the the first method there, stripping off
119 	 * the extra register in the process.
120 	 */
121 	if (rs5c->smbus) {
122 		int addr = RS5C_ADDR(RS5C372_REG_SECS);
123 		int size = sizeof(rs5c->buf) - 1;
124 
125 		if (i2c_smbus_read_i2c_block_data(client, addr, size,
126 						  rs5c->buf + 1) != size) {
127 			dev_warn(&client->dev, "can't read registers\n");
128 			return -EIO;
129 		}
130 	} else {
131 		if ((i2c_transfer(client->adapter, msgs, 1)) != 1) {
132 			dev_warn(&client->dev, "can't read registers\n");
133 			return -EIO;
134 		}
135 	}
136 
137 	dev_dbg(&client->dev,
138 		"%02x %02x %02x (%02x) %02x %02x %02x (%02x), "
139 		"%02x %02x %02x, %02x %02x %02x; %02x %02x\n",
140 		rs5c->regs[0],  rs5c->regs[1],  rs5c->regs[2],  rs5c->regs[3],
141 		rs5c->regs[4],  rs5c->regs[5],  rs5c->regs[6],  rs5c->regs[7],
142 		rs5c->regs[8],  rs5c->regs[9],  rs5c->regs[10], rs5c->regs[11],
143 		rs5c->regs[12], rs5c->regs[13], rs5c->regs[14], rs5c->regs[15]);
144 
145 	return 0;
146 }
147 
148 static unsigned rs5c_reg2hr(struct rs5c372 *rs5c, unsigned reg)
149 {
150 	unsigned	hour;
151 
152 	if (rs5c->time24)
153 		return bcd2bin(reg & 0x3f);
154 
155 	hour = bcd2bin(reg & 0x1f);
156 	if (hour == 12)
157 		hour = 0;
158 	if (reg & 0x20)
159 		hour += 12;
160 	return hour;
161 }
162 
163 static unsigned rs5c_hr2reg(struct rs5c372 *rs5c, unsigned hour)
164 {
165 	if (rs5c->time24)
166 		return bin2bcd(hour);
167 
168 	if (hour > 12)
169 		return 0x20 | bin2bcd(hour - 12);
170 	if (hour == 12)
171 		return 0x20 | bin2bcd(12);
172 	if (hour == 0)
173 		return bin2bcd(12);
174 	return bin2bcd(hour);
175 }
176 
177 static int rs5c372_get_datetime(struct i2c_client *client, struct rtc_time *tm)
178 {
179 	struct rs5c372	*rs5c = i2c_get_clientdata(client);
180 	int		status = rs5c_get_regs(rs5c);
181 
182 	if (status < 0)
183 		return status;
184 
185 	tm->tm_sec = bcd2bin(rs5c->regs[RS5C372_REG_SECS] & 0x7f);
186 	tm->tm_min = bcd2bin(rs5c->regs[RS5C372_REG_MINS] & 0x7f);
187 	tm->tm_hour = rs5c_reg2hr(rs5c, rs5c->regs[RS5C372_REG_HOURS]);
188 
189 	tm->tm_wday = bcd2bin(rs5c->regs[RS5C372_REG_WDAY] & 0x07);
190 	tm->tm_mday = bcd2bin(rs5c->regs[RS5C372_REG_DAY] & 0x3f);
191 
192 	/* tm->tm_mon is zero-based */
193 	tm->tm_mon = bcd2bin(rs5c->regs[RS5C372_REG_MONTH] & 0x1f) - 1;
194 
195 	/* year is 1900 + tm->tm_year */
196 	tm->tm_year = bcd2bin(rs5c->regs[RS5C372_REG_YEAR]) + 100;
197 
198 	dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
199 		"mday=%d, mon=%d, year=%d, wday=%d\n",
200 		__func__,
201 		tm->tm_sec, tm->tm_min, tm->tm_hour,
202 		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
203 
204 	/* rtc might need initialization */
205 	return rtc_valid_tm(tm);
206 }
207 
208 static int rs5c372_set_datetime(struct i2c_client *client, struct rtc_time *tm)
209 {
210 	struct rs5c372	*rs5c = i2c_get_clientdata(client);
211 	unsigned char	buf[7];
212 	int		addr;
213 
214 	dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d "
215 		"mday=%d, mon=%d, year=%d, wday=%d\n",
216 		__func__,
217 		tm->tm_sec, tm->tm_min, tm->tm_hour,
218 		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
219 
220 	addr   = RS5C_ADDR(RS5C372_REG_SECS);
221 	buf[0] = bin2bcd(tm->tm_sec);
222 	buf[1] = bin2bcd(tm->tm_min);
223 	buf[2] = rs5c_hr2reg(rs5c, tm->tm_hour);
224 	buf[3] = bin2bcd(tm->tm_wday);
225 	buf[4] = bin2bcd(tm->tm_mday);
226 	buf[5] = bin2bcd(tm->tm_mon + 1);
227 	buf[6] = bin2bcd(tm->tm_year - 100);
228 
229 	if (i2c_smbus_write_i2c_block_data(client, addr, sizeof(buf), buf) < 0) {
230 		dev_err(&client->dev, "%s: write error\n", __func__);
231 		return -EIO;
232 	}
233 
234 	return 0;
235 }
236 
237 #if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
238 #define	NEED_TRIM
239 #endif
240 
241 #if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE)
242 #define	NEED_TRIM
243 #endif
244 
245 #ifdef	NEED_TRIM
246 static int rs5c372_get_trim(struct i2c_client *client, int *osc, int *trim)
247 {
248 	struct rs5c372 *rs5c372 = i2c_get_clientdata(client);
249 	u8 tmp = rs5c372->regs[RS5C372_REG_TRIM];
250 
251 	if (osc)
252 		*osc = (tmp & RS5C372_TRIM_XSL) ? 32000 : 32768;
253 
254 	if (trim) {
255 		dev_dbg(&client->dev, "%s: raw trim=%x\n", __func__, tmp);
256 		tmp &= RS5C372_TRIM_MASK;
257 		if (tmp & 0x3e) {
258 			int t = tmp & 0x3f;
259 
260 			if (tmp & 0x40)
261 				t = (~t | (s8)0xc0) + 1;
262 			else
263 				t = t - 1;
264 
265 			tmp = t * 2;
266 		} else
267 			tmp = 0;
268 		*trim = tmp;
269 	}
270 
271 	return 0;
272 }
273 #endif
274 
275 static int rs5c372_rtc_read_time(struct device *dev, struct rtc_time *tm)
276 {
277 	return rs5c372_get_datetime(to_i2c_client(dev), tm);
278 }
279 
280 static int rs5c372_rtc_set_time(struct device *dev, struct rtc_time *tm)
281 {
282 	return rs5c372_set_datetime(to_i2c_client(dev), tm);
283 }
284 
285 
286 static int rs5c_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
287 {
288 	struct i2c_client	*client = to_i2c_client(dev);
289 	struct rs5c372		*rs5c = i2c_get_clientdata(client);
290 	unsigned char		buf;
291 	int			status, addr;
292 
293 	buf = rs5c->regs[RS5C_REG_CTRL1];
294 
295 	if (!rs5c->has_irq)
296 		return -EINVAL;
297 
298 	status = rs5c_get_regs(rs5c);
299 	if (status < 0)
300 		return status;
301 
302 	addr = RS5C_ADDR(RS5C_REG_CTRL1);
303 	if (enabled)
304 		buf |= RS5C_CTRL1_AALE;
305 	else
306 		buf &= ~RS5C_CTRL1_AALE;
307 
308 	if (i2c_smbus_write_byte_data(client, addr, buf) < 0) {
309 		printk(KERN_WARNING "%s: can't update alarm\n",
310 			rs5c->rtc->name);
311 		status = -EIO;
312 	} else
313 		rs5c->regs[RS5C_REG_CTRL1] = buf;
314 
315 	return status;
316 }
317 
318 
319 /* NOTE:  Since RTC_WKALM_{RD,SET} were originally defined for EFI,
320  * which only exposes a polled programming interface; and since
321  * these calls map directly to those EFI requests; we don't demand
322  * we have an IRQ for this chip when we go through this API.
323  *
324  * The older x86_pc derived RTC_ALM_{READ,SET} calls require irqs
325  * though, managed through RTC_AIE_{ON,OFF} requests.
326  */
327 
328 static int rs5c_read_alarm(struct device *dev, struct rtc_wkalrm *t)
329 {
330 	struct i2c_client	*client = to_i2c_client(dev);
331 	struct rs5c372		*rs5c = i2c_get_clientdata(client);
332 	int			status;
333 
334 	status = rs5c_get_regs(rs5c);
335 	if (status < 0)
336 		return status;
337 
338 	/* report alarm time */
339 	t->time.tm_sec = 0;
340 	t->time.tm_min = bcd2bin(rs5c->regs[RS5C_REG_ALARM_A_MIN] & 0x7f);
341 	t->time.tm_hour = rs5c_reg2hr(rs5c, rs5c->regs[RS5C_REG_ALARM_A_HOURS]);
342 	t->time.tm_mday = -1;
343 	t->time.tm_mon = -1;
344 	t->time.tm_year = -1;
345 	t->time.tm_wday = -1;
346 	t->time.tm_yday = -1;
347 	t->time.tm_isdst = -1;
348 
349 	/* ... and status */
350 	t->enabled = !!(rs5c->regs[RS5C_REG_CTRL1] & RS5C_CTRL1_AALE);
351 	t->pending = !!(rs5c->regs[RS5C_REG_CTRL2] & RS5C_CTRL2_AAFG);
352 
353 	return 0;
354 }
355 
356 static int rs5c_set_alarm(struct device *dev, struct rtc_wkalrm *t)
357 {
358 	struct i2c_client	*client = to_i2c_client(dev);
359 	struct rs5c372		*rs5c = i2c_get_clientdata(client);
360 	int			status, addr, i;
361 	unsigned char		buf[3];
362 
363 	/* only handle up to 24 hours in the future, like RTC_ALM_SET */
364 	if (t->time.tm_mday != -1
365 			|| t->time.tm_mon != -1
366 			|| t->time.tm_year != -1)
367 		return -EINVAL;
368 
369 	/* REVISIT: round up tm_sec */
370 
371 	/* if needed, disable irq (clears pending status) */
372 	status = rs5c_get_regs(rs5c);
373 	if (status < 0)
374 		return status;
375 	if (rs5c->regs[RS5C_REG_CTRL1] & RS5C_CTRL1_AALE) {
376 		addr = RS5C_ADDR(RS5C_REG_CTRL1);
377 		buf[0] = rs5c->regs[RS5C_REG_CTRL1] & ~RS5C_CTRL1_AALE;
378 		if (i2c_smbus_write_byte_data(client, addr, buf[0]) < 0) {
379 			pr_debug("%s: can't disable alarm\n", rs5c->rtc->name);
380 			return -EIO;
381 		}
382 		rs5c->regs[RS5C_REG_CTRL1] = buf[0];
383 	}
384 
385 	/* set alarm */
386 	buf[0] = bin2bcd(t->time.tm_min);
387 	buf[1] = rs5c_hr2reg(rs5c, t->time.tm_hour);
388 	buf[2] = 0x7f;	/* any/all days */
389 
390 	for (i = 0; i < sizeof(buf); i++) {
391 		addr = RS5C_ADDR(RS5C_REG_ALARM_A_MIN + i);
392 		if (i2c_smbus_write_byte_data(client, addr, buf[i]) < 0) {
393 			pr_debug("%s: can't set alarm time\n", rs5c->rtc->name);
394 			return -EIO;
395 		}
396 	}
397 
398 	/* ... and maybe enable its irq */
399 	if (t->enabled) {
400 		addr = RS5C_ADDR(RS5C_REG_CTRL1);
401 		buf[0] = rs5c->regs[RS5C_REG_CTRL1] | RS5C_CTRL1_AALE;
402 		if (i2c_smbus_write_byte_data(client, addr, buf[0]) < 0)
403 			printk(KERN_WARNING "%s: can't enable alarm\n",
404 				rs5c->rtc->name);
405 		rs5c->regs[RS5C_REG_CTRL1] = buf[0];
406 	}
407 
408 	return 0;
409 }
410 
411 #if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
412 
413 static int rs5c372_rtc_proc(struct device *dev, struct seq_file *seq)
414 {
415 	int err, osc, trim;
416 
417 	err = rs5c372_get_trim(to_i2c_client(dev), &osc, &trim);
418 	if (err == 0) {
419 		seq_printf(seq, "crystal\t\t: %d.%03d KHz\n",
420 				osc / 1000, osc % 1000);
421 		seq_printf(seq, "trim\t\t: %d\n", trim);
422 	}
423 
424 	return 0;
425 }
426 
427 #else
428 #define	rs5c372_rtc_proc	NULL
429 #endif
430 
431 static const struct rtc_class_ops rs5c372_rtc_ops = {
432 	.proc		= rs5c372_rtc_proc,
433 	.read_time	= rs5c372_rtc_read_time,
434 	.set_time	= rs5c372_rtc_set_time,
435 	.read_alarm	= rs5c_read_alarm,
436 	.set_alarm	= rs5c_set_alarm,
437 	.alarm_irq_enable = rs5c_rtc_alarm_irq_enable,
438 };
439 
440 #if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE)
441 
442 static ssize_t rs5c372_sysfs_show_trim(struct device *dev,
443 				struct device_attribute *attr, char *buf)
444 {
445 	int err, trim;
446 
447 	err = rs5c372_get_trim(to_i2c_client(dev), NULL, &trim);
448 	if (err)
449 		return err;
450 
451 	return sprintf(buf, "%d\n", trim);
452 }
453 static DEVICE_ATTR(trim, S_IRUGO, rs5c372_sysfs_show_trim, NULL);
454 
455 static ssize_t rs5c372_sysfs_show_osc(struct device *dev,
456 				struct device_attribute *attr, char *buf)
457 {
458 	int err, osc;
459 
460 	err = rs5c372_get_trim(to_i2c_client(dev), &osc, NULL);
461 	if (err)
462 		return err;
463 
464 	return sprintf(buf, "%d.%03d KHz\n", osc / 1000, osc % 1000);
465 }
466 static DEVICE_ATTR(osc, S_IRUGO, rs5c372_sysfs_show_osc, NULL);
467 
468 static int rs5c_sysfs_register(struct device *dev)
469 {
470 	int err;
471 
472 	err = device_create_file(dev, &dev_attr_trim);
473 	if (err)
474 		return err;
475 	err = device_create_file(dev, &dev_attr_osc);
476 	if (err)
477 		device_remove_file(dev, &dev_attr_trim);
478 
479 	return err;
480 }
481 
482 static void rs5c_sysfs_unregister(struct device *dev)
483 {
484 	device_remove_file(dev, &dev_attr_trim);
485 	device_remove_file(dev, &dev_attr_osc);
486 }
487 
488 #else
489 static int rs5c_sysfs_register(struct device *dev)
490 {
491 	return 0;
492 }
493 
494 static void rs5c_sysfs_unregister(struct device *dev)
495 {
496 	/* nothing */
497 }
498 #endif	/* SYSFS */
499 
500 static struct i2c_driver rs5c372_driver;
501 
502 static int rs5c_oscillator_setup(struct rs5c372 *rs5c372)
503 {
504 	unsigned char buf[2];
505 	int addr, i, ret = 0;
506 
507 	if (rs5c372->type == rtc_r2025sd) {
508 		if (!(rs5c372->regs[RS5C_REG_CTRL2] & R2025_CTRL2_XST))
509 			return ret;
510 		rs5c372->regs[RS5C_REG_CTRL2] &= ~R2025_CTRL2_XST;
511 	} else {
512 		if (!(rs5c372->regs[RS5C_REG_CTRL2] & RS5C_CTRL2_XSTP))
513 			return ret;
514 		rs5c372->regs[RS5C_REG_CTRL2] &= ~RS5C_CTRL2_XSTP;
515 	}
516 
517 	addr   = RS5C_ADDR(RS5C_REG_CTRL1);
518 	buf[0] = rs5c372->regs[RS5C_REG_CTRL1];
519 	buf[1] = rs5c372->regs[RS5C_REG_CTRL2];
520 
521 	/* use 24hr mode */
522 	switch (rs5c372->type) {
523 	case rtc_rs5c372a:
524 	case rtc_rs5c372b:
525 		buf[1] |= RS5C372_CTRL2_24;
526 		rs5c372->time24 = 1;
527 		break;
528 	case rtc_r2025sd:
529 	case rtc_rv5c386:
530 	case rtc_rv5c387a:
531 		buf[0] |= RV5C387_CTRL1_24;
532 		rs5c372->time24 = 1;
533 		break;
534 	default:
535 		/* impossible */
536 		break;
537 	}
538 
539 	for (i = 0; i < sizeof(buf); i++) {
540 		addr = RS5C_ADDR(RS5C_REG_CTRL1 + i);
541 		ret = i2c_smbus_write_byte_data(rs5c372->client, addr, buf[i]);
542 		if (unlikely(ret < 0))
543 			return ret;
544 	}
545 
546 	rs5c372->regs[RS5C_REG_CTRL1] = buf[0];
547 	rs5c372->regs[RS5C_REG_CTRL2] = buf[1];
548 
549 	return 0;
550 }
551 
552 static int rs5c372_probe(struct i2c_client *client,
553 			 const struct i2c_device_id *id)
554 {
555 	int err = 0;
556 	int smbus_mode = 0;
557 	struct rs5c372 *rs5c372;
558 	struct rtc_time tm;
559 
560 	dev_dbg(&client->dev, "%s\n", __func__);
561 
562 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
563 			I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK)) {
564 		/*
565 		 * If we don't have any master mode adapter, try breaking
566 		 * it down in to the barest of capabilities.
567 		 */
568 		if (i2c_check_functionality(client->adapter,
569 				I2C_FUNC_SMBUS_BYTE_DATA |
570 				I2C_FUNC_SMBUS_I2C_BLOCK))
571 			smbus_mode = 1;
572 		else {
573 			/* Still no good, give up */
574 			err = -ENODEV;
575 			goto exit;
576 		}
577 	}
578 
579 	if (!(rs5c372 = kzalloc(sizeof(struct rs5c372), GFP_KERNEL))) {
580 		err = -ENOMEM;
581 		goto exit;
582 	}
583 
584 	rs5c372->client = client;
585 	i2c_set_clientdata(client, rs5c372);
586 	rs5c372->type = id->driver_data;
587 
588 	/* we read registers 0x0f then 0x00-0x0f; skip the first one */
589 	rs5c372->regs = &rs5c372->buf[1];
590 	rs5c372->smbus = smbus_mode;
591 
592 	err = rs5c_get_regs(rs5c372);
593 	if (err < 0)
594 		goto exit_kfree;
595 
596 	/* clock may be set for am/pm or 24 hr time */
597 	switch (rs5c372->type) {
598 	case rtc_rs5c372a:
599 	case rtc_rs5c372b:
600 		/* alarm uses ALARM_A; and nINTRA on 372a, nINTR on 372b.
601 		 * so does periodic irq, except some 327a modes.
602 		 */
603 		if (rs5c372->regs[RS5C_REG_CTRL2] & RS5C372_CTRL2_24)
604 			rs5c372->time24 = 1;
605 		break;
606 	case rtc_r2025sd:
607 	case rtc_rv5c386:
608 	case rtc_rv5c387a:
609 		if (rs5c372->regs[RS5C_REG_CTRL1] & RV5C387_CTRL1_24)
610 			rs5c372->time24 = 1;
611 		/* alarm uses ALARM_W; and nINTRB for alarm and periodic
612 		 * irq, on both 386 and 387
613 		 */
614 		break;
615 	default:
616 		dev_err(&client->dev, "unknown RTC type\n");
617 		goto exit_kfree;
618 	}
619 
620 	/* if the oscillator lost power and no other software (like
621 	 * the bootloader) set it up, do it here.
622 	 *
623 	 * The R2025S/D does this a little differently than the other
624 	 * parts, so we special case that..
625 	 */
626 	err = rs5c_oscillator_setup(rs5c372);
627 	if (unlikely(err < 0)) {
628 		dev_err(&client->dev, "setup error\n");
629 		goto exit_kfree;
630 	}
631 
632 	if (rs5c372_get_datetime(client, &tm) < 0)
633 		dev_warn(&client->dev, "clock needs to be set\n");
634 
635 	dev_info(&client->dev, "%s found, %s, driver version " DRV_VERSION "\n",
636 			({ char *s; switch (rs5c372->type) {
637 			case rtc_r2025sd:	s = "r2025sd"; 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 
649 	rs5c372->rtc = rtc_device_register(rs5c372_driver.driver.name,
650 				&client->dev, &rs5c372_rtc_ops, THIS_MODULE);
651 
652 	if (IS_ERR(rs5c372->rtc)) {
653 		err = PTR_ERR(rs5c372->rtc);
654 		goto exit_kfree;
655 	}
656 
657 	err = rs5c_sysfs_register(&client->dev);
658 	if (err)
659 		goto exit_devreg;
660 
661 	return 0;
662 
663 exit_devreg:
664 	rtc_device_unregister(rs5c372->rtc);
665 
666 exit_kfree:
667 	kfree(rs5c372);
668 
669 exit:
670 	return err;
671 }
672 
673 static int rs5c372_remove(struct i2c_client *client)
674 {
675 	struct rs5c372 *rs5c372 = i2c_get_clientdata(client);
676 
677 	rtc_device_unregister(rs5c372->rtc);
678 	rs5c_sysfs_unregister(&client->dev);
679 	kfree(rs5c372);
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