xref: /openbmc/linux/drivers/rtc/rtc-rs5c372.c (revision df2634f43f5106947f3735a0b61a6527a4b278cd)
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 #if defined(CONFIG_RTC_INTF_DEV) || defined(CONFIG_RTC_INTF_DEV_MODULE)
285 
286 static int
287 rs5c_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
288 {
289 	struct i2c_client	*client = to_i2c_client(dev);
290 	struct rs5c372		*rs5c = i2c_get_clientdata(client);
291 	unsigned char		buf;
292 	int			status, addr;
293 
294 	buf = rs5c->regs[RS5C_REG_CTRL1];
295 	switch (cmd) {
296 	case RTC_UIE_OFF:
297 	case RTC_UIE_ON:
298 		/* some 327a modes use a different IRQ pin for 1Hz irqs */
299 		if (rs5c->type == rtc_rs5c372a
300 				&& (buf & RS5C372A_CTRL1_SL1))
301 			return -ENOIOCTLCMD;
302 	default:
303 		return -ENOIOCTLCMD;
304 	}
305 
306 	status = rs5c_get_regs(rs5c);
307 	if (status < 0)
308 		return status;
309 
310 	addr = RS5C_ADDR(RS5C_REG_CTRL1);
311 	switch (cmd) {
312 	case RTC_UIE_OFF:	/* update off */
313 		buf &= ~RS5C_CTRL1_CT_MASK;
314 		break;
315 	case RTC_UIE_ON:	/* update on */
316 		buf &= ~RS5C_CTRL1_CT_MASK;
317 		buf |= RS5C_CTRL1_CT4;
318 		break;
319 	}
320 
321 	if (i2c_smbus_write_byte_data(client, addr, buf) < 0) {
322 		printk(KERN_WARNING "%s: can't update alarm\n",
323 			rs5c->rtc->name);
324 		status = -EIO;
325 	} else
326 		rs5c->regs[RS5C_REG_CTRL1] = buf;
327 
328 	return status;
329 }
330 
331 #else
332 #define	rs5c_rtc_ioctl	NULL
333 #endif
334 
335 
336 static int rs5c_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
337 {
338 	struct i2c_client	*client = to_i2c_client(dev);
339 	struct rs5c372		*rs5c = i2c_get_clientdata(client);
340 	unsigned char		buf;
341 	int			status, addr;
342 
343 	buf = rs5c->regs[RS5C_REG_CTRL1];
344 
345 	if (!rs5c->has_irq)
346 		return -EINVAL;
347 
348 	status = rs5c_get_regs(rs5c);
349 	if (status < 0)
350 		return status;
351 
352 	addr = RS5C_ADDR(RS5C_REG_CTRL1);
353 	if (enabled)
354 		buf |= RS5C_CTRL1_AALE;
355 	else
356 		buf &= ~RS5C_CTRL1_AALE;
357 
358 	if (i2c_smbus_write_byte_data(client, addr, buf) < 0) {
359 		printk(KERN_WARNING "%s: can't update alarm\n",
360 			rs5c->rtc->name);
361 		status = -EIO;
362 	} else
363 		rs5c->regs[RS5C_REG_CTRL1] = buf;
364 
365 	return status;
366 }
367 
368 
369 /* NOTE:  Since RTC_WKALM_{RD,SET} were originally defined for EFI,
370  * which only exposes a polled programming interface; and since
371  * these calls map directly to those EFI requests; we don't demand
372  * we have an IRQ for this chip when we go through this API.
373  *
374  * The older x86_pc derived RTC_ALM_{READ,SET} calls require irqs
375  * though, managed through RTC_AIE_{ON,OFF} requests.
376  */
377 
378 static int rs5c_read_alarm(struct device *dev, struct rtc_wkalrm *t)
379 {
380 	struct i2c_client	*client = to_i2c_client(dev);
381 	struct rs5c372		*rs5c = i2c_get_clientdata(client);
382 	int			status;
383 
384 	status = rs5c_get_regs(rs5c);
385 	if (status < 0)
386 		return status;
387 
388 	/* report alarm time */
389 	t->time.tm_sec = 0;
390 	t->time.tm_min = bcd2bin(rs5c->regs[RS5C_REG_ALARM_A_MIN] & 0x7f);
391 	t->time.tm_hour = rs5c_reg2hr(rs5c, rs5c->regs[RS5C_REG_ALARM_A_HOURS]);
392 	t->time.tm_mday = -1;
393 	t->time.tm_mon = -1;
394 	t->time.tm_year = -1;
395 	t->time.tm_wday = -1;
396 	t->time.tm_yday = -1;
397 	t->time.tm_isdst = -1;
398 
399 	/* ... and status */
400 	t->enabled = !!(rs5c->regs[RS5C_REG_CTRL1] & RS5C_CTRL1_AALE);
401 	t->pending = !!(rs5c->regs[RS5C_REG_CTRL2] & RS5C_CTRL2_AAFG);
402 
403 	return 0;
404 }
405 
406 static int rs5c_set_alarm(struct device *dev, struct rtc_wkalrm *t)
407 {
408 	struct i2c_client	*client = to_i2c_client(dev);
409 	struct rs5c372		*rs5c = i2c_get_clientdata(client);
410 	int			status, addr, i;
411 	unsigned char		buf[3];
412 
413 	/* only handle up to 24 hours in the future, like RTC_ALM_SET */
414 	if (t->time.tm_mday != -1
415 			|| t->time.tm_mon != -1
416 			|| t->time.tm_year != -1)
417 		return -EINVAL;
418 
419 	/* REVISIT: round up tm_sec */
420 
421 	/* if needed, disable irq (clears pending status) */
422 	status = rs5c_get_regs(rs5c);
423 	if (status < 0)
424 		return status;
425 	if (rs5c->regs[RS5C_REG_CTRL1] & RS5C_CTRL1_AALE) {
426 		addr = RS5C_ADDR(RS5C_REG_CTRL1);
427 		buf[0] = rs5c->regs[RS5C_REG_CTRL1] & ~RS5C_CTRL1_AALE;
428 		if (i2c_smbus_write_byte_data(client, addr, buf[0]) < 0) {
429 			pr_debug("%s: can't disable alarm\n", rs5c->rtc->name);
430 			return -EIO;
431 		}
432 		rs5c->regs[RS5C_REG_CTRL1] = buf[0];
433 	}
434 
435 	/* set alarm */
436 	buf[0] = bin2bcd(t->time.tm_min);
437 	buf[1] = rs5c_hr2reg(rs5c, t->time.tm_hour);
438 	buf[2] = 0x7f;	/* any/all days */
439 
440 	for (i = 0; i < sizeof(buf); i++) {
441 		addr = RS5C_ADDR(RS5C_REG_ALARM_A_MIN + i);
442 		if (i2c_smbus_write_byte_data(client, addr, buf[i]) < 0) {
443 			pr_debug("%s: can't set alarm time\n", rs5c->rtc->name);
444 			return -EIO;
445 		}
446 	}
447 
448 	/* ... and maybe enable its irq */
449 	if (t->enabled) {
450 		addr = RS5C_ADDR(RS5C_REG_CTRL1);
451 		buf[0] = rs5c->regs[RS5C_REG_CTRL1] | RS5C_CTRL1_AALE;
452 		if (i2c_smbus_write_byte_data(client, addr, buf[0]) < 0)
453 			printk(KERN_WARNING "%s: can't enable alarm\n",
454 				rs5c->rtc->name);
455 		rs5c->regs[RS5C_REG_CTRL1] = buf[0];
456 	}
457 
458 	return 0;
459 }
460 
461 #if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
462 
463 static int rs5c372_rtc_proc(struct device *dev, struct seq_file *seq)
464 {
465 	int err, osc, trim;
466 
467 	err = rs5c372_get_trim(to_i2c_client(dev), &osc, &trim);
468 	if (err == 0) {
469 		seq_printf(seq, "crystal\t\t: %d.%03d KHz\n",
470 				osc / 1000, osc % 1000);
471 		seq_printf(seq, "trim\t\t: %d\n", trim);
472 	}
473 
474 	return 0;
475 }
476 
477 #else
478 #define	rs5c372_rtc_proc	NULL
479 #endif
480 
481 static const struct rtc_class_ops rs5c372_rtc_ops = {
482 	.proc		= rs5c372_rtc_proc,
483 	.ioctl		= rs5c_rtc_ioctl,
484 	.read_time	= rs5c372_rtc_read_time,
485 	.set_time	= rs5c372_rtc_set_time,
486 	.read_alarm	= rs5c_read_alarm,
487 	.set_alarm	= rs5c_set_alarm,
488 	.alarm_irq_enable = rs5c_rtc_alarm_irq_enable,
489 };
490 
491 #if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE)
492 
493 static ssize_t rs5c372_sysfs_show_trim(struct device *dev,
494 				struct device_attribute *attr, char *buf)
495 {
496 	int err, trim;
497 
498 	err = rs5c372_get_trim(to_i2c_client(dev), NULL, &trim);
499 	if (err)
500 		return err;
501 
502 	return sprintf(buf, "%d\n", trim);
503 }
504 static DEVICE_ATTR(trim, S_IRUGO, rs5c372_sysfs_show_trim, NULL);
505 
506 static ssize_t rs5c372_sysfs_show_osc(struct device *dev,
507 				struct device_attribute *attr, char *buf)
508 {
509 	int err, osc;
510 
511 	err = rs5c372_get_trim(to_i2c_client(dev), &osc, NULL);
512 	if (err)
513 		return err;
514 
515 	return sprintf(buf, "%d.%03d KHz\n", osc / 1000, osc % 1000);
516 }
517 static DEVICE_ATTR(osc, S_IRUGO, rs5c372_sysfs_show_osc, NULL);
518 
519 static int rs5c_sysfs_register(struct device *dev)
520 {
521 	int err;
522 
523 	err = device_create_file(dev, &dev_attr_trim);
524 	if (err)
525 		return err;
526 	err = device_create_file(dev, &dev_attr_osc);
527 	if (err)
528 		device_remove_file(dev, &dev_attr_trim);
529 
530 	return err;
531 }
532 
533 static void rs5c_sysfs_unregister(struct device *dev)
534 {
535 	device_remove_file(dev, &dev_attr_trim);
536 	device_remove_file(dev, &dev_attr_osc);
537 }
538 
539 #else
540 static int rs5c_sysfs_register(struct device *dev)
541 {
542 	return 0;
543 }
544 
545 static void rs5c_sysfs_unregister(struct device *dev)
546 {
547 	/* nothing */
548 }
549 #endif	/* SYSFS */
550 
551 static struct i2c_driver rs5c372_driver;
552 
553 static int rs5c_oscillator_setup(struct rs5c372 *rs5c372)
554 {
555 	unsigned char buf[2];
556 	int addr, i, ret = 0;
557 
558 	if (rs5c372->type == rtc_r2025sd) {
559 		if (!(rs5c372->regs[RS5C_REG_CTRL2] & R2025_CTRL2_XST))
560 			return ret;
561 		rs5c372->regs[RS5C_REG_CTRL2] &= ~R2025_CTRL2_XST;
562 	} else {
563 		if (!(rs5c372->regs[RS5C_REG_CTRL2] & RS5C_CTRL2_XSTP))
564 			return ret;
565 		rs5c372->regs[RS5C_REG_CTRL2] &= ~RS5C_CTRL2_XSTP;
566 	}
567 
568 	addr   = RS5C_ADDR(RS5C_REG_CTRL1);
569 	buf[0] = rs5c372->regs[RS5C_REG_CTRL1];
570 	buf[1] = rs5c372->regs[RS5C_REG_CTRL2];
571 
572 	/* use 24hr mode */
573 	switch (rs5c372->type) {
574 	case rtc_rs5c372a:
575 	case rtc_rs5c372b:
576 		buf[1] |= RS5C372_CTRL2_24;
577 		rs5c372->time24 = 1;
578 		break;
579 	case rtc_r2025sd:
580 	case rtc_rv5c386:
581 	case rtc_rv5c387a:
582 		buf[0] |= RV5C387_CTRL1_24;
583 		rs5c372->time24 = 1;
584 		break;
585 	default:
586 		/* impossible */
587 		break;
588 	}
589 
590 	for (i = 0; i < sizeof(buf); i++) {
591 		addr = RS5C_ADDR(RS5C_REG_CTRL1 + i);
592 		ret = i2c_smbus_write_byte_data(rs5c372->client, addr, buf[i]);
593 		if (unlikely(ret < 0))
594 			return ret;
595 	}
596 
597 	rs5c372->regs[RS5C_REG_CTRL1] = buf[0];
598 	rs5c372->regs[RS5C_REG_CTRL2] = buf[1];
599 
600 	return 0;
601 }
602 
603 static int rs5c372_probe(struct i2c_client *client,
604 			 const struct i2c_device_id *id)
605 {
606 	int err = 0;
607 	int smbus_mode = 0;
608 	struct rs5c372 *rs5c372;
609 	struct rtc_time tm;
610 
611 	dev_dbg(&client->dev, "%s\n", __func__);
612 
613 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
614 			I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK)) {
615 		/*
616 		 * If we don't have any master mode adapter, try breaking
617 		 * it down in to the barest of capabilities.
618 		 */
619 		if (i2c_check_functionality(client->adapter,
620 				I2C_FUNC_SMBUS_BYTE_DATA |
621 				I2C_FUNC_SMBUS_I2C_BLOCK))
622 			smbus_mode = 1;
623 		else {
624 			/* Still no good, give up */
625 			err = -ENODEV;
626 			goto exit;
627 		}
628 	}
629 
630 	if (!(rs5c372 = kzalloc(sizeof(struct rs5c372), GFP_KERNEL))) {
631 		err = -ENOMEM;
632 		goto exit;
633 	}
634 
635 	rs5c372->client = client;
636 	i2c_set_clientdata(client, rs5c372);
637 	rs5c372->type = id->driver_data;
638 
639 	/* we read registers 0x0f then 0x00-0x0f; skip the first one */
640 	rs5c372->regs = &rs5c372->buf[1];
641 	rs5c372->smbus = smbus_mode;
642 
643 	err = rs5c_get_regs(rs5c372);
644 	if (err < 0)
645 		goto exit_kfree;
646 
647 	/* clock may be set for am/pm or 24 hr time */
648 	switch (rs5c372->type) {
649 	case rtc_rs5c372a:
650 	case rtc_rs5c372b:
651 		/* alarm uses ALARM_A; and nINTRA on 372a, nINTR on 372b.
652 		 * so does periodic irq, except some 327a modes.
653 		 */
654 		if (rs5c372->regs[RS5C_REG_CTRL2] & RS5C372_CTRL2_24)
655 			rs5c372->time24 = 1;
656 		break;
657 	case rtc_r2025sd:
658 	case rtc_rv5c386:
659 	case rtc_rv5c387a:
660 		if (rs5c372->regs[RS5C_REG_CTRL1] & RV5C387_CTRL1_24)
661 			rs5c372->time24 = 1;
662 		/* alarm uses ALARM_W; and nINTRB for alarm and periodic
663 		 * irq, on both 386 and 387
664 		 */
665 		break;
666 	default:
667 		dev_err(&client->dev, "unknown RTC type\n");
668 		goto exit_kfree;
669 	}
670 
671 	/* if the oscillator lost power and no other software (like
672 	 * the bootloader) set it up, do it here.
673 	 *
674 	 * The R2025S/D does this a little differently than the other
675 	 * parts, so we special case that..
676 	 */
677 	err = rs5c_oscillator_setup(rs5c372);
678 	if (unlikely(err < 0)) {
679 		dev_err(&client->dev, "setup error\n");
680 		goto exit_kfree;
681 	}
682 
683 	if (rs5c372_get_datetime(client, &tm) < 0)
684 		dev_warn(&client->dev, "clock needs to be set\n");
685 
686 	dev_info(&client->dev, "%s found, %s, driver version " DRV_VERSION "\n",
687 			({ char *s; switch (rs5c372->type) {
688 			case rtc_r2025sd:	s = "r2025sd"; break;
689 			case rtc_rs5c372a:	s = "rs5c372a"; break;
690 			case rtc_rs5c372b:	s = "rs5c372b"; break;
691 			case rtc_rv5c386:	s = "rv5c386"; break;
692 			case rtc_rv5c387a:	s = "rv5c387a"; break;
693 			default:		s = "chip"; break;
694 			}; s;}),
695 			rs5c372->time24 ? "24hr" : "am/pm"
696 			);
697 
698 	/* REVISIT use client->irq to register alarm irq ... */
699 
700 	rs5c372->rtc = rtc_device_register(rs5c372_driver.driver.name,
701 				&client->dev, &rs5c372_rtc_ops, THIS_MODULE);
702 
703 	if (IS_ERR(rs5c372->rtc)) {
704 		err = PTR_ERR(rs5c372->rtc);
705 		goto exit_kfree;
706 	}
707 
708 	err = rs5c_sysfs_register(&client->dev);
709 	if (err)
710 		goto exit_devreg;
711 
712 	return 0;
713 
714 exit_devreg:
715 	rtc_device_unregister(rs5c372->rtc);
716 
717 exit_kfree:
718 	kfree(rs5c372);
719 
720 exit:
721 	return err;
722 }
723 
724 static int rs5c372_remove(struct i2c_client *client)
725 {
726 	struct rs5c372 *rs5c372 = i2c_get_clientdata(client);
727 
728 	rtc_device_unregister(rs5c372->rtc);
729 	rs5c_sysfs_unregister(&client->dev);
730 	kfree(rs5c372);
731 	return 0;
732 }
733 
734 static struct i2c_driver rs5c372_driver = {
735 	.driver		= {
736 		.name	= "rtc-rs5c372",
737 	},
738 	.probe		= rs5c372_probe,
739 	.remove		= rs5c372_remove,
740 	.id_table	= rs5c372_id,
741 };
742 
743 static __init int rs5c372_init(void)
744 {
745 	return i2c_add_driver(&rs5c372_driver);
746 }
747 
748 static __exit void rs5c372_exit(void)
749 {
750 	i2c_del_driver(&rs5c372_driver);
751 }
752 
753 module_init(rs5c372_init);
754 module_exit(rs5c372_exit);
755 
756 MODULE_AUTHOR(
757 		"Pavel Mironchik <pmironchik@optifacio.net>, "
758 		"Alessandro Zummo <a.zummo@towertech.it>, "
759 		"Paul Mundt <lethal@linux-sh.org>");
760 MODULE_DESCRIPTION("Ricoh RS5C372 RTC driver");
761 MODULE_LICENSE("GPL");
762 MODULE_VERSION(DRV_VERSION);
763