xref: /linux/drivers/rtc/rtc-rs5c372.c (revision bcefe12eff5dca6fdfa94ed85e5bee66380d5cd9)
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 
17 #define DRV_VERSION "0.6"
18 
19 
20 /*
21  * Ricoh has a family of I2C based RTCs, which differ only slightly from
22  * each other.  Differences center on pinout (e.g. how many interrupts,
23  * output clock, etc) and how the control registers are used.  The '372
24  * is significant only because that's the one this driver first supported.
25  */
26 #define RS5C372_REG_SECS	0
27 #define RS5C372_REG_MINS	1
28 #define RS5C372_REG_HOURS	2
29 #define RS5C372_REG_WDAY	3
30 #define RS5C372_REG_DAY		4
31 #define RS5C372_REG_MONTH	5
32 #define RS5C372_REG_YEAR	6
33 #define RS5C372_REG_TRIM	7
34 #	define RS5C372_TRIM_XSL		0x80
35 #	define RS5C372_TRIM_MASK	0x7F
36 
37 #define RS5C_REG_ALARM_A_MIN	8			/* or ALARM_W */
38 #define RS5C_REG_ALARM_A_HOURS	9
39 #define RS5C_REG_ALARM_A_WDAY	10
40 
41 #define RS5C_REG_ALARM_B_MIN	11			/* or ALARM_D */
42 #define RS5C_REG_ALARM_B_HOURS	12
43 #define RS5C_REG_ALARM_B_WDAY	13			/* (ALARM_B only) */
44 
45 #define RS5C_REG_CTRL1		14
46 #	define RS5C_CTRL1_AALE		(1 << 7)	/* or WALE */
47 #	define RS5C_CTRL1_BALE		(1 << 6)	/* or DALE */
48 #	define RV5C387_CTRL1_24		(1 << 5)
49 #	define RS5C372A_CTRL1_SL1	(1 << 5)
50 #	define RS5C_CTRL1_CT_MASK	(7 << 0)
51 #	define RS5C_CTRL1_CT0		(0 << 0)	/* no periodic irq */
52 #	define RS5C_CTRL1_CT4		(4 << 0)	/* 1 Hz level irq */
53 #define RS5C_REG_CTRL2		15
54 #	define RS5C372_CTRL2_24		(1 << 5)
55 #	define R2025_CTRL2_XST		(1 << 5)
56 #	define RS5C_CTRL2_XSTP		(1 << 4)	/* only if !R2025S/D */
57 #	define RS5C_CTRL2_CTFG		(1 << 2)
58 #	define RS5C_CTRL2_AAFG		(1 << 1)	/* or WAFG */
59 #	define RS5C_CTRL2_BAFG		(1 << 0)	/* or DAFG */
60 
61 
62 /* to read (style 1) or write registers starting at R */
63 #define RS5C_ADDR(R)		(((R) << 4) | 0)
64 
65 
66 enum rtc_type {
67 	rtc_undef = 0,
68 	rtc_r2025sd,
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 	{ "rs5c372a", rtc_rs5c372a },
78 	{ "rs5c372b", rtc_rs5c372b },
79 	{ "rv5c386", rtc_rv5c386 },
80 	{ "rv5c387a", rtc_rv5c387a },
81 	{ }
82 };
83 MODULE_DEVICE_TABLE(i2c, rs5c372_id);
84 
85 /* REVISIT:  this assumes that:
86  *  - we're in the 21st century, so it's safe to ignore the century
87  *    bit for rv5c38[67] (REG_MONTH bit 7);
88  *  - we should use ALARM_A not ALARM_B (may be wrong on some boards)
89  */
90 struct rs5c372 {
91 	struct i2c_client	*client;
92 	struct rtc_device	*rtc;
93 	enum rtc_type		type;
94 	unsigned		time24:1;
95 	unsigned		has_irq:1;
96 	unsigned		smbus:1;
97 	char			buf[17];
98 	char			*regs;
99 };
100 
101 static int rs5c_get_regs(struct rs5c372 *rs5c)
102 {
103 	struct i2c_client	*client = rs5c->client;
104 	struct i2c_msg		msgs[] = {
105 		{ client->addr, I2C_M_RD, sizeof rs5c->buf, rs5c->buf },
106 	};
107 
108 	/* This implements the third reading method from the datasheet, using
109 	 * an internal address that's reset after each transaction (by STOP)
110 	 * to 0x0f ... so we read extra registers, and skip the first one.
111 	 *
112 	 * The first method doesn't work with the iop3xx adapter driver, on at
113 	 * least 80219 chips; this works around that bug.
114 	 *
115 	 * The third method on the other hand doesn't work for the SMBus-only
116 	 * configurations, so we use the the first method there, stripping off
117 	 * the extra register in the process.
118 	 */
119 	if (rs5c->smbus) {
120 		int addr = RS5C_ADDR(RS5C372_REG_SECS);
121 		int size = sizeof(rs5c->buf) - 1;
122 
123 		if (i2c_smbus_read_i2c_block_data(client, addr, size,
124 						  rs5c->buf + 1) != size) {
125 			dev_warn(&client->dev, "can't read registers\n");
126 			return -EIO;
127 		}
128 	} else {
129 		if ((i2c_transfer(client->adapter, msgs, 1)) != 1) {
130 			dev_warn(&client->dev, "can't read registers\n");
131 			return -EIO;
132 		}
133 	}
134 
135 	dev_dbg(&client->dev,
136 		"%02x %02x %02x (%02x) %02x %02x %02x (%02x), "
137 		"%02x %02x %02x, %02x %02x %02x; %02x %02x\n",
138 		rs5c->regs[0],  rs5c->regs[1],  rs5c->regs[2],  rs5c->regs[3],
139 		rs5c->regs[4],  rs5c->regs[5],  rs5c->regs[6],  rs5c->regs[7],
140 		rs5c->regs[8],  rs5c->regs[9],  rs5c->regs[10], rs5c->regs[11],
141 		rs5c->regs[12], rs5c->regs[13], rs5c->regs[14], rs5c->regs[15]);
142 
143 	return 0;
144 }
145 
146 static unsigned rs5c_reg2hr(struct rs5c372 *rs5c, unsigned reg)
147 {
148 	unsigned	hour;
149 
150 	if (rs5c->time24)
151 		return bcd2bin(reg & 0x3f);
152 
153 	hour = bcd2bin(reg & 0x1f);
154 	if (hour == 12)
155 		hour = 0;
156 	if (reg & 0x20)
157 		hour += 12;
158 	return hour;
159 }
160 
161 static unsigned rs5c_hr2reg(struct rs5c372 *rs5c, unsigned hour)
162 {
163 	if (rs5c->time24)
164 		return bin2bcd(hour);
165 
166 	if (hour > 12)
167 		return 0x20 | bin2bcd(hour - 12);
168 	if (hour == 12)
169 		return 0x20 | bin2bcd(12);
170 	if (hour == 0)
171 		return bin2bcd(12);
172 	return bin2bcd(hour);
173 }
174 
175 static int rs5c372_get_datetime(struct i2c_client *client, struct rtc_time *tm)
176 {
177 	struct rs5c372	*rs5c = i2c_get_clientdata(client);
178 	int		status = rs5c_get_regs(rs5c);
179 
180 	if (status < 0)
181 		return status;
182 
183 	tm->tm_sec = bcd2bin(rs5c->regs[RS5C372_REG_SECS] & 0x7f);
184 	tm->tm_min = bcd2bin(rs5c->regs[RS5C372_REG_MINS] & 0x7f);
185 	tm->tm_hour = rs5c_reg2hr(rs5c, rs5c->regs[RS5C372_REG_HOURS]);
186 
187 	tm->tm_wday = bcd2bin(rs5c->regs[RS5C372_REG_WDAY] & 0x07);
188 	tm->tm_mday = bcd2bin(rs5c->regs[RS5C372_REG_DAY] & 0x3f);
189 
190 	/* tm->tm_mon is zero-based */
191 	tm->tm_mon = bcd2bin(rs5c->regs[RS5C372_REG_MONTH] & 0x1f) - 1;
192 
193 	/* year is 1900 + tm->tm_year */
194 	tm->tm_year = bcd2bin(rs5c->regs[RS5C372_REG_YEAR]) + 100;
195 
196 	dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
197 		"mday=%d, mon=%d, year=%d, wday=%d\n",
198 		__func__,
199 		tm->tm_sec, tm->tm_min, tm->tm_hour,
200 		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
201 
202 	/* rtc might need initialization */
203 	return rtc_valid_tm(tm);
204 }
205 
206 static int rs5c372_set_datetime(struct i2c_client *client, struct rtc_time *tm)
207 {
208 	struct rs5c372	*rs5c = i2c_get_clientdata(client);
209 	unsigned char	buf[8];
210 	int		addr;
211 
212 	dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d "
213 		"mday=%d, mon=%d, year=%d, wday=%d\n",
214 		__func__,
215 		tm->tm_sec, tm->tm_min, tm->tm_hour,
216 		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
217 
218 	addr   = RS5C_ADDR(RS5C372_REG_SECS);
219 	buf[0] = bin2bcd(tm->tm_sec);
220 	buf[1] = bin2bcd(tm->tm_min);
221 	buf[2] = rs5c_hr2reg(rs5c, tm->tm_hour);
222 	buf[3] = bin2bcd(tm->tm_wday);
223 	buf[4] = bin2bcd(tm->tm_mday);
224 	buf[5] = bin2bcd(tm->tm_mon + 1);
225 	buf[6] = bin2bcd(tm->tm_year - 100);
226 
227 	if (i2c_smbus_write_i2c_block_data(client, addr, sizeof(buf), buf) < 0) {
228 		dev_err(&client->dev, "%s: write error\n", __func__);
229 		return -EIO;
230 	}
231 
232 	return 0;
233 }
234 
235 #if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
236 #define	NEED_TRIM
237 #endif
238 
239 #if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE)
240 #define	NEED_TRIM
241 #endif
242 
243 #ifdef	NEED_TRIM
244 static int rs5c372_get_trim(struct i2c_client *client, int *osc, int *trim)
245 {
246 	struct rs5c372 *rs5c372 = i2c_get_clientdata(client);
247 	u8 tmp = rs5c372->regs[RS5C372_REG_TRIM];
248 
249 	if (osc)
250 		*osc = (tmp & RS5C372_TRIM_XSL) ? 32000 : 32768;
251 
252 	if (trim) {
253 		dev_dbg(&client->dev, "%s: raw trim=%x\n", __func__, tmp);
254 		tmp &= RS5C372_TRIM_MASK;
255 		if (tmp & 0x3e) {
256 			int t = tmp & 0x3f;
257 
258 			if (tmp & 0x40)
259 				t = (~t | (s8)0xc0) + 1;
260 			else
261 				t = t - 1;
262 
263 			tmp = t * 2;
264 		} else
265 			tmp = 0;
266 		*trim = tmp;
267 	}
268 
269 	return 0;
270 }
271 #endif
272 
273 static int rs5c372_rtc_read_time(struct device *dev, struct rtc_time *tm)
274 {
275 	return rs5c372_get_datetime(to_i2c_client(dev), tm);
276 }
277 
278 static int rs5c372_rtc_set_time(struct device *dev, struct rtc_time *tm)
279 {
280 	return rs5c372_set_datetime(to_i2c_client(dev), tm);
281 }
282 
283 #if defined(CONFIG_RTC_INTF_DEV) || defined(CONFIG_RTC_INTF_DEV_MODULE)
284 
285 static int
286 rs5c_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
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 	switch (cmd) {
295 	case RTC_UIE_OFF:
296 	case RTC_UIE_ON:
297 		/* some 327a modes use a different IRQ pin for 1Hz irqs */
298 		if (rs5c->type == rtc_rs5c372a
299 				&& (buf & RS5C372A_CTRL1_SL1))
300 			return -ENOIOCTLCMD;
301 	case RTC_AIE_OFF:
302 	case RTC_AIE_ON:
303 		/* these irq management calls only make sense for chips
304 		 * which are wired up to an IRQ.
305 		 */
306 		if (!rs5c->has_irq)
307 			return -ENOIOCTLCMD;
308 		break;
309 	default:
310 		return -ENOIOCTLCMD;
311 	}
312 
313 	status = rs5c_get_regs(rs5c);
314 	if (status < 0)
315 		return status;
316 
317 	addr = RS5C_ADDR(RS5C_REG_CTRL1);
318 	switch (cmd) {
319 	case RTC_AIE_OFF:	/* alarm off */
320 		buf &= ~RS5C_CTRL1_AALE;
321 		break;
322 	case RTC_AIE_ON:	/* alarm on */
323 		buf |= RS5C_CTRL1_AALE;
324 		break;
325 	case RTC_UIE_OFF:	/* update off */
326 		buf &= ~RS5C_CTRL1_CT_MASK;
327 		break;
328 	case RTC_UIE_ON:	/* update on */
329 		buf &= ~RS5C_CTRL1_CT_MASK;
330 		buf |= RS5C_CTRL1_CT4;
331 		break;
332 	}
333 
334 	if (i2c_smbus_write_byte_data(client, addr, buf) < 0) {
335 		printk(KERN_WARNING "%s: can't update alarm\n",
336 			rs5c->rtc->name);
337 		status = -EIO;
338 	} else
339 		rs5c->regs[RS5C_REG_CTRL1] = buf;
340 
341 	return status;
342 }
343 
344 #else
345 #define	rs5c_rtc_ioctl	NULL
346 #endif
347 
348 
349 /* NOTE:  Since RTC_WKALM_{RD,SET} were originally defined for EFI,
350  * which only exposes a polled programming interface; and since
351  * these calls map directly to those EFI requests; we don't demand
352  * we have an IRQ for this chip when we go through this API.
353  *
354  * The older x86_pc derived RTC_ALM_{READ,SET} calls require irqs
355  * though, managed through RTC_AIE_{ON,OFF} requests.
356  */
357 
358 static int rs5c_read_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;
363 
364 	status = rs5c_get_regs(rs5c);
365 	if (status < 0)
366 		return status;
367 
368 	/* report alarm time */
369 	t->time.tm_sec = 0;
370 	t->time.tm_min = bcd2bin(rs5c->regs[RS5C_REG_ALARM_A_MIN] & 0x7f);
371 	t->time.tm_hour = rs5c_reg2hr(rs5c, rs5c->regs[RS5C_REG_ALARM_A_HOURS]);
372 	t->time.tm_mday = -1;
373 	t->time.tm_mon = -1;
374 	t->time.tm_year = -1;
375 	t->time.tm_wday = -1;
376 	t->time.tm_yday = -1;
377 	t->time.tm_isdst = -1;
378 
379 	/* ... and status */
380 	t->enabled = !!(rs5c->regs[RS5C_REG_CTRL1] & RS5C_CTRL1_AALE);
381 	t->pending = !!(rs5c->regs[RS5C_REG_CTRL2] & RS5C_CTRL2_AAFG);
382 
383 	return 0;
384 }
385 
386 static int rs5c_set_alarm(struct device *dev, struct rtc_wkalrm *t)
387 {
388 	struct i2c_client	*client = to_i2c_client(dev);
389 	struct rs5c372		*rs5c = i2c_get_clientdata(client);
390 	int			status, addr, i;
391 	unsigned char		buf[3];
392 
393 	/* only handle up to 24 hours in the future, like RTC_ALM_SET */
394 	if (t->time.tm_mday != -1
395 			|| t->time.tm_mon != -1
396 			|| t->time.tm_year != -1)
397 		return -EINVAL;
398 
399 	/* REVISIT: round up tm_sec */
400 
401 	/* if needed, disable irq (clears pending status) */
402 	status = rs5c_get_regs(rs5c);
403 	if (status < 0)
404 		return status;
405 	if (rs5c->regs[RS5C_REG_CTRL1] & RS5C_CTRL1_AALE) {
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 			pr_debug("%s: can't disable alarm\n", rs5c->rtc->name);
410 			return -EIO;
411 		}
412 		rs5c->regs[RS5C_REG_CTRL1] = buf[0];
413 	}
414 
415 	/* set alarm */
416 	buf[0] = bin2bcd(t->time.tm_min);
417 	buf[1] = rs5c_hr2reg(rs5c, t->time.tm_hour);
418 	buf[2] = 0x7f;	/* any/all days */
419 
420 	for (i = 0; i < sizeof(buf); i++) {
421 		addr = RS5C_ADDR(RS5C_REG_ALARM_A_MIN + i);
422 		if (i2c_smbus_write_byte_data(client, addr, buf[i]) < 0) {
423 			pr_debug("%s: can't set alarm time\n", rs5c->rtc->name);
424 			return -EIO;
425 		}
426 	}
427 
428 	/* ... and maybe enable its irq */
429 	if (t->enabled) {
430 		addr = RS5C_ADDR(RS5C_REG_CTRL1);
431 		buf[0] = rs5c->regs[RS5C_REG_CTRL1] | RS5C_CTRL1_AALE;
432 		if (i2c_smbus_write_byte_data(client, addr, buf[0]) < 0)
433 			printk(KERN_WARNING "%s: can't enable alarm\n",
434 				rs5c->rtc->name);
435 		rs5c->regs[RS5C_REG_CTRL1] = buf[0];
436 	}
437 
438 	return 0;
439 }
440 
441 #if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
442 
443 static int rs5c372_rtc_proc(struct device *dev, struct seq_file *seq)
444 {
445 	int err, osc, trim;
446 
447 	err = rs5c372_get_trim(to_i2c_client(dev), &osc, &trim);
448 	if (err == 0) {
449 		seq_printf(seq, "crystal\t\t: %d.%03d KHz\n",
450 				osc / 1000, osc % 1000);
451 		seq_printf(seq, "trim\t\t: %d\n", trim);
452 	}
453 
454 	return 0;
455 }
456 
457 #else
458 #define	rs5c372_rtc_proc	NULL
459 #endif
460 
461 static const struct rtc_class_ops rs5c372_rtc_ops = {
462 	.proc		= rs5c372_rtc_proc,
463 	.ioctl		= rs5c_rtc_ioctl,
464 	.read_time	= rs5c372_rtc_read_time,
465 	.set_time	= rs5c372_rtc_set_time,
466 	.read_alarm	= rs5c_read_alarm,
467 	.set_alarm	= rs5c_set_alarm,
468 };
469 
470 #if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE)
471 
472 static ssize_t rs5c372_sysfs_show_trim(struct device *dev,
473 				struct device_attribute *attr, char *buf)
474 {
475 	int err, trim;
476 
477 	err = rs5c372_get_trim(to_i2c_client(dev), NULL, &trim);
478 	if (err)
479 		return err;
480 
481 	return sprintf(buf, "%d\n", trim);
482 }
483 static DEVICE_ATTR(trim, S_IRUGO, rs5c372_sysfs_show_trim, NULL);
484 
485 static ssize_t rs5c372_sysfs_show_osc(struct device *dev,
486 				struct device_attribute *attr, char *buf)
487 {
488 	int err, osc;
489 
490 	err = rs5c372_get_trim(to_i2c_client(dev), &osc, NULL);
491 	if (err)
492 		return err;
493 
494 	return sprintf(buf, "%d.%03d KHz\n", osc / 1000, osc % 1000);
495 }
496 static DEVICE_ATTR(osc, S_IRUGO, rs5c372_sysfs_show_osc, NULL);
497 
498 static int rs5c_sysfs_register(struct device *dev)
499 {
500 	int err;
501 
502 	err = device_create_file(dev, &dev_attr_trim);
503 	if (err)
504 		return err;
505 	err = device_create_file(dev, &dev_attr_osc);
506 	if (err)
507 		device_remove_file(dev, &dev_attr_trim);
508 
509 	return err;
510 }
511 
512 static void rs5c_sysfs_unregister(struct device *dev)
513 {
514 	device_remove_file(dev, &dev_attr_trim);
515 	device_remove_file(dev, &dev_attr_osc);
516 }
517 
518 #else
519 static int rs5c_sysfs_register(struct device *dev)
520 {
521 	return 0;
522 }
523 
524 static void rs5c_sysfs_unregister(struct device *dev)
525 {
526 	/* nothing */
527 }
528 #endif	/* SYSFS */
529 
530 static struct i2c_driver rs5c372_driver;
531 
532 static int rs5c_oscillator_setup(struct rs5c372 *rs5c372)
533 {
534 	unsigned char buf[2];
535 	int addr, i, ret = 0;
536 
537 	if (rs5c372->type == rtc_r2025sd) {
538 		if (!(rs5c372->regs[RS5C_REG_CTRL2] & R2025_CTRL2_XST))
539 			return ret;
540 		rs5c372->regs[RS5C_REG_CTRL2] &= ~R2025_CTRL2_XST;
541 	} else {
542 		if (!(rs5c372->regs[RS5C_REG_CTRL2] & RS5C_CTRL2_XSTP))
543 			return ret;
544 		rs5c372->regs[RS5C_REG_CTRL2] &= ~RS5C_CTRL2_XSTP;
545 	}
546 
547 	addr   = RS5C_ADDR(RS5C_REG_CTRL1);
548 	buf[0] = rs5c372->regs[RS5C_REG_CTRL1];
549 	buf[1] = rs5c372->regs[RS5C_REG_CTRL2];
550 
551 	/* use 24hr mode */
552 	switch (rs5c372->type) {
553 	case rtc_rs5c372a:
554 	case rtc_rs5c372b:
555 		buf[1] |= RS5C372_CTRL2_24;
556 		rs5c372->time24 = 1;
557 		break;
558 	case rtc_r2025sd:
559 	case rtc_rv5c386:
560 	case rtc_rv5c387a:
561 		buf[0] |= RV5C387_CTRL1_24;
562 		rs5c372->time24 = 1;
563 		break;
564 	default:
565 		/* impossible */
566 		break;
567 	}
568 
569 	for (i = 0; i < sizeof(buf); i++) {
570 		addr = RS5C_ADDR(RS5C_REG_CTRL1 + i);
571 		ret = i2c_smbus_write_byte_data(rs5c372->client, addr, buf[i]);
572 		if (unlikely(ret < 0))
573 			return ret;
574 	}
575 
576 	rs5c372->regs[RS5C_REG_CTRL1] = buf[0];
577 	rs5c372->regs[RS5C_REG_CTRL2] = buf[1];
578 
579 	return 0;
580 }
581 
582 static int rs5c372_probe(struct i2c_client *client,
583 			 const struct i2c_device_id *id)
584 {
585 	int err = 0;
586 	int smbus_mode = 0;
587 	struct rs5c372 *rs5c372;
588 	struct rtc_time tm;
589 
590 	dev_dbg(&client->dev, "%s\n", __func__);
591 
592 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
593 			I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK)) {
594 		/*
595 		 * If we don't have any master mode adapter, try breaking
596 		 * it down in to the barest of capabilities.
597 		 */
598 		if (i2c_check_functionality(client->adapter,
599 				I2C_FUNC_SMBUS_BYTE_DATA |
600 				I2C_FUNC_SMBUS_I2C_BLOCK))
601 			smbus_mode = 1;
602 		else {
603 			/* Still no good, give up */
604 			err = -ENODEV;
605 			goto exit;
606 		}
607 	}
608 
609 	if (!(rs5c372 = kzalloc(sizeof(struct rs5c372), GFP_KERNEL))) {
610 		err = -ENOMEM;
611 		goto exit;
612 	}
613 
614 	rs5c372->client = client;
615 	i2c_set_clientdata(client, rs5c372);
616 	rs5c372->type = id->driver_data;
617 
618 	/* we read registers 0x0f then 0x00-0x0f; skip the first one */
619 	rs5c372->regs = &rs5c372->buf[1];
620 	rs5c372->smbus = smbus_mode;
621 
622 	err = rs5c_get_regs(rs5c372);
623 	if (err < 0)
624 		goto exit_kfree;
625 
626 	/* clock may be set for am/pm or 24 hr time */
627 	switch (rs5c372->type) {
628 	case rtc_rs5c372a:
629 	case rtc_rs5c372b:
630 		/* alarm uses ALARM_A; and nINTRA on 372a, nINTR on 372b.
631 		 * so does periodic irq, except some 327a modes.
632 		 */
633 		if (rs5c372->regs[RS5C_REG_CTRL2] & RS5C372_CTRL2_24)
634 			rs5c372->time24 = 1;
635 		break;
636 	case rtc_r2025sd:
637 	case rtc_rv5c386:
638 	case rtc_rv5c387a:
639 		if (rs5c372->regs[RS5C_REG_CTRL1] & RV5C387_CTRL1_24)
640 			rs5c372->time24 = 1;
641 		/* alarm uses ALARM_W; and nINTRB for alarm and periodic
642 		 * irq, on both 386 and 387
643 		 */
644 		break;
645 	default:
646 		dev_err(&client->dev, "unknown RTC type\n");
647 		goto exit_kfree;
648 	}
649 
650 	/* if the oscillator lost power and no other software (like
651 	 * the bootloader) set it up, do it here.
652 	 *
653 	 * The R2025S/D does this a little differently than the other
654 	 * parts, so we special case that..
655 	 */
656 	err = rs5c_oscillator_setup(rs5c372);
657 	if (unlikely(err < 0)) {
658 		dev_err(&client->dev, "setup error\n");
659 		goto exit_kfree;
660 	}
661 
662 	if (rs5c372_get_datetime(client, &tm) < 0)
663 		dev_warn(&client->dev, "clock needs to be set\n");
664 
665 	dev_info(&client->dev, "%s found, %s, driver version " DRV_VERSION "\n",
666 			({ char *s; switch (rs5c372->type) {
667 			case rtc_r2025sd:	s = "r2025sd"; break;
668 			case rtc_rs5c372a:	s = "rs5c372a"; break;
669 			case rtc_rs5c372b:	s = "rs5c372b"; break;
670 			case rtc_rv5c386:	s = "rv5c386"; break;
671 			case rtc_rv5c387a:	s = "rv5c387a"; break;
672 			default:		s = "chip"; break;
673 			}; s;}),
674 			rs5c372->time24 ? "24hr" : "am/pm"
675 			);
676 
677 	/* REVISIT use client->irq to register alarm irq ... */
678 
679 	rs5c372->rtc = rtc_device_register(rs5c372_driver.driver.name,
680 				&client->dev, &rs5c372_rtc_ops, THIS_MODULE);
681 
682 	if (IS_ERR(rs5c372->rtc)) {
683 		err = PTR_ERR(rs5c372->rtc);
684 		goto exit_kfree;
685 	}
686 
687 	err = rs5c_sysfs_register(&client->dev);
688 	if (err)
689 		goto exit_devreg;
690 
691 	return 0;
692 
693 exit_devreg:
694 	rtc_device_unregister(rs5c372->rtc);
695 
696 exit_kfree:
697 	kfree(rs5c372);
698 
699 exit:
700 	return err;
701 }
702 
703 static int rs5c372_remove(struct i2c_client *client)
704 {
705 	struct rs5c372 *rs5c372 = i2c_get_clientdata(client);
706 
707 	rtc_device_unregister(rs5c372->rtc);
708 	rs5c_sysfs_unregister(&client->dev);
709 	kfree(rs5c372);
710 	return 0;
711 }
712 
713 static struct i2c_driver rs5c372_driver = {
714 	.driver		= {
715 		.name	= "rtc-rs5c372",
716 	},
717 	.probe		= rs5c372_probe,
718 	.remove		= rs5c372_remove,
719 	.id_table	= rs5c372_id,
720 };
721 
722 static __init int rs5c372_init(void)
723 {
724 	return i2c_add_driver(&rs5c372_driver);
725 }
726 
727 static __exit void rs5c372_exit(void)
728 {
729 	i2c_del_driver(&rs5c372_driver);
730 }
731 
732 module_init(rs5c372_init);
733 module_exit(rs5c372_exit);
734 
735 MODULE_AUTHOR(
736 		"Pavel Mironchik <pmironchik@optifacio.net>, "
737 		"Alessandro Zummo <a.zummo@towertech.it>, "
738 		"Paul Mundt <lethal@linux-sh.org>");
739 MODULE_DESCRIPTION("Ricoh RS5C372 RTC driver");
740 MODULE_LICENSE("GPL");
741 MODULE_VERSION(DRV_VERSION);
742