xref: /openbmc/linux/drivers/rtc/rtc-rs5c372.c (revision 3213486f)
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 #include <linux/of_device.h>
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 RS5C_CTRL2_XSTP		(1 << 4)	/* only if !R2x2x */
56 #	define R2x2x_CTRL2_VDET		(1 << 6)	/* only if  R2x2x */
57 #	define R2x2x_CTRL2_XSTP		(1 << 5)	/* only if  R2x2x */
58 #	define R2x2x_CTRL2_PON		(1 << 4)	/* only if  R2x2x */
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 static const struct of_device_id rs5c372_of_match[] = {
90 	{
91 		.compatible = "ricoh,r2025sd",
92 		.data = (void *)rtc_r2025sd
93 	},
94 	{
95 		.compatible = "ricoh,r2221tl",
96 		.data = (void *)rtc_r2221tl
97 	},
98 	{
99 		.compatible = "ricoh,rs5c372a",
100 		.data = (void *)rtc_rs5c372a
101 	},
102 	{
103 		.compatible = "ricoh,rs5c372b",
104 		.data = (void *)rtc_rs5c372b
105 	},
106 	{
107 		.compatible = "ricoh,rv5c386",
108 		.data = (void *)rtc_rv5c386
109 	},
110 	{
111 		.compatible = "ricoh,rv5c387a",
112 		.data = (void *)rtc_rv5c387a
113 	},
114 	{ }
115 };
116 MODULE_DEVICE_TABLE(of, rs5c372_of_match);
117 
118 /* REVISIT:  this assumes that:
119  *  - we're in the 21st century, so it's safe to ignore the century
120  *    bit for rv5c38[67] (REG_MONTH bit 7);
121  *  - we should use ALARM_A not ALARM_B (may be wrong on some boards)
122  */
123 struct rs5c372 {
124 	struct i2c_client	*client;
125 	struct rtc_device	*rtc;
126 	enum rtc_type		type;
127 	unsigned		time24:1;
128 	unsigned		has_irq:1;
129 	unsigned		smbus:1;
130 	char			buf[17];
131 	char			*regs;
132 };
133 
134 static int rs5c_get_regs(struct rs5c372 *rs5c)
135 {
136 	struct i2c_client	*client = rs5c->client;
137 	struct i2c_msg		msgs[] = {
138 		{
139 			.addr = client->addr,
140 			.flags = I2C_M_RD,
141 			.len = sizeof(rs5c->buf),
142 			.buf = rs5c->buf
143 		},
144 	};
145 
146 	/* This implements the third reading method from the datasheet, using
147 	 * an internal address that's reset after each transaction (by STOP)
148 	 * to 0x0f ... so we read extra registers, and skip the first one.
149 	 *
150 	 * The first method doesn't work with the iop3xx adapter driver, on at
151 	 * least 80219 chips; this works around that bug.
152 	 *
153 	 * The third method on the other hand doesn't work for the SMBus-only
154 	 * configurations, so we use the the first method there, stripping off
155 	 * the extra register in the process.
156 	 */
157 	if (rs5c->smbus) {
158 		int addr = RS5C_ADDR(RS5C372_REG_SECS);
159 		int size = sizeof(rs5c->buf) - 1;
160 
161 		if (i2c_smbus_read_i2c_block_data(client, addr, size,
162 						  rs5c->buf + 1) != size) {
163 			dev_warn(&client->dev, "can't read registers\n");
164 			return -EIO;
165 		}
166 	} else {
167 		if ((i2c_transfer(client->adapter, msgs, 1)) != 1) {
168 			dev_warn(&client->dev, "can't read registers\n");
169 			return -EIO;
170 		}
171 	}
172 
173 	dev_dbg(&client->dev,
174 		"%3ph (%02x) %3ph (%02x), %3ph, %3ph; %02x %02x\n",
175 		rs5c->regs + 0, rs5c->regs[3],
176 		rs5c->regs + 4, rs5c->regs[7],
177 		rs5c->regs + 8, rs5c->regs + 11,
178 		rs5c->regs[14], rs5c->regs[15]);
179 
180 	return 0;
181 }
182 
183 static unsigned rs5c_reg2hr(struct rs5c372 *rs5c, unsigned reg)
184 {
185 	unsigned	hour;
186 
187 	if (rs5c->time24)
188 		return bcd2bin(reg & 0x3f);
189 
190 	hour = bcd2bin(reg & 0x1f);
191 	if (hour == 12)
192 		hour = 0;
193 	if (reg & 0x20)
194 		hour += 12;
195 	return hour;
196 }
197 
198 static unsigned rs5c_hr2reg(struct rs5c372 *rs5c, unsigned hour)
199 {
200 	if (rs5c->time24)
201 		return bin2bcd(hour);
202 
203 	if (hour > 12)
204 		return 0x20 | bin2bcd(hour - 12);
205 	if (hour == 12)
206 		return 0x20 | bin2bcd(12);
207 	if (hour == 0)
208 		return bin2bcd(12);
209 	return bin2bcd(hour);
210 }
211 
212 static int rs5c372_rtc_read_time(struct device *dev, struct rtc_time *tm)
213 {
214 	struct i2c_client *client = to_i2c_client(dev);
215 	struct rs5c372	*rs5c = i2c_get_clientdata(client);
216 	int		status = rs5c_get_regs(rs5c);
217 	unsigned char ctrl2 = rs5c->regs[RS5C_REG_CTRL2];
218 
219 	if (status < 0)
220 		return status;
221 
222 	switch (rs5c->type) {
223 	case rtc_r2025sd:
224 	case rtc_r2221tl:
225 		if ((rs5c->type == rtc_r2025sd && !(ctrl2 & R2x2x_CTRL2_XSTP)) ||
226 		    (rs5c->type == rtc_r2221tl &&  (ctrl2 & R2x2x_CTRL2_XSTP))) {
227 			dev_warn(&client->dev, "rtc oscillator interruption detected. Please reset the rtc clock.\n");
228 			return -EINVAL;
229 		}
230 		break;
231 	default:
232 		if (ctrl2 & RS5C_CTRL2_XSTP) {
233 			dev_warn(&client->dev, "rtc oscillator interruption detected. Please reset the rtc clock.\n");
234 			return -EINVAL;
235 		}
236 	}
237 
238 	tm->tm_sec = bcd2bin(rs5c->regs[RS5C372_REG_SECS] & 0x7f);
239 	tm->tm_min = bcd2bin(rs5c->regs[RS5C372_REG_MINS] & 0x7f);
240 	tm->tm_hour = rs5c_reg2hr(rs5c, rs5c->regs[RS5C372_REG_HOURS]);
241 
242 	tm->tm_wday = bcd2bin(rs5c->regs[RS5C372_REG_WDAY] & 0x07);
243 	tm->tm_mday = bcd2bin(rs5c->regs[RS5C372_REG_DAY] & 0x3f);
244 
245 	/* tm->tm_mon is zero-based */
246 	tm->tm_mon = bcd2bin(rs5c->regs[RS5C372_REG_MONTH] & 0x1f) - 1;
247 
248 	/* year is 1900 + tm->tm_year */
249 	tm->tm_year = bcd2bin(rs5c->regs[RS5C372_REG_YEAR]) + 100;
250 
251 	dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
252 		"mday=%d, mon=%d, year=%d, wday=%d\n",
253 		__func__,
254 		tm->tm_sec, tm->tm_min, tm->tm_hour,
255 		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
256 
257 	return 0;
258 }
259 
260 static int rs5c372_rtc_set_time(struct device *dev, struct rtc_time *tm)
261 {
262 	struct i2c_client *client = to_i2c_client(dev);
263 	struct rs5c372	*rs5c = i2c_get_clientdata(client);
264 	unsigned char	buf[7];
265 	unsigned char	ctrl2;
266 	int		addr;
267 
268 	dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d "
269 		"mday=%d, mon=%d, year=%d, wday=%d\n",
270 		__func__,
271 		tm->tm_sec, tm->tm_min, tm->tm_hour,
272 		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
273 
274 	addr   = RS5C_ADDR(RS5C372_REG_SECS);
275 	buf[0] = bin2bcd(tm->tm_sec);
276 	buf[1] = bin2bcd(tm->tm_min);
277 	buf[2] = rs5c_hr2reg(rs5c, tm->tm_hour);
278 	buf[3] = bin2bcd(tm->tm_wday);
279 	buf[4] = bin2bcd(tm->tm_mday);
280 	buf[5] = bin2bcd(tm->tm_mon + 1);
281 	buf[6] = bin2bcd(tm->tm_year - 100);
282 
283 	if (i2c_smbus_write_i2c_block_data(client, addr, sizeof(buf), buf) < 0) {
284 		dev_dbg(&client->dev, "%s: write error in line %i\n",
285 			__func__, __LINE__);
286 		return -EIO;
287 	}
288 
289 	addr = RS5C_ADDR(RS5C_REG_CTRL2);
290 	ctrl2 = i2c_smbus_read_byte_data(client, addr);
291 
292 	/* clear rtc warning bits */
293 	switch (rs5c->type) {
294 	case rtc_r2025sd:
295 	case rtc_r2221tl:
296 		ctrl2 &= ~(R2x2x_CTRL2_VDET | R2x2x_CTRL2_PON);
297 		if (rs5c->type == rtc_r2025sd)
298 			ctrl2 |= R2x2x_CTRL2_XSTP;
299 		else
300 			ctrl2 &= ~R2x2x_CTRL2_XSTP;
301 		break;
302 	default:
303 		ctrl2 &= ~RS5C_CTRL2_XSTP;
304 		break;
305 	}
306 
307 	if (i2c_smbus_write_byte_data(client, addr, ctrl2) < 0) {
308 		dev_dbg(&client->dev, "%s: write error in line %i\n",
309 			__func__, __LINE__);
310 		return -EIO;
311 	}
312 
313 	return 0;
314 }
315 
316 #if IS_ENABLED(CONFIG_RTC_INTF_PROC)
317 #define	NEED_TRIM
318 #endif
319 
320 #if IS_ENABLED(CONFIG_RTC_INTF_SYSFS)
321 #define	NEED_TRIM
322 #endif
323 
324 #ifdef	NEED_TRIM
325 static int rs5c372_get_trim(struct i2c_client *client, int *osc, int *trim)
326 {
327 	struct rs5c372 *rs5c372 = i2c_get_clientdata(client);
328 	u8 tmp = rs5c372->regs[RS5C372_REG_TRIM];
329 
330 	if (osc)
331 		*osc = (tmp & RS5C372_TRIM_XSL) ? 32000 : 32768;
332 
333 	if (trim) {
334 		dev_dbg(&client->dev, "%s: raw trim=%x\n", __func__, tmp);
335 		tmp &= RS5C372_TRIM_MASK;
336 		if (tmp & 0x3e) {
337 			int t = tmp & 0x3f;
338 
339 			if (tmp & 0x40)
340 				t = (~t | (s8)0xc0) + 1;
341 			else
342 				t = t - 1;
343 
344 			tmp = t * 2;
345 		} else
346 			tmp = 0;
347 		*trim = tmp;
348 	}
349 
350 	return 0;
351 }
352 #endif
353 
354 static int rs5c_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
355 {
356 	struct i2c_client	*client = to_i2c_client(dev);
357 	struct rs5c372		*rs5c = i2c_get_clientdata(client);
358 	unsigned char		buf;
359 	int			status, addr;
360 
361 	buf = rs5c->regs[RS5C_REG_CTRL1];
362 
363 	if (!rs5c->has_irq)
364 		return -EINVAL;
365 
366 	status = rs5c_get_regs(rs5c);
367 	if (status < 0)
368 		return status;
369 
370 	addr = RS5C_ADDR(RS5C_REG_CTRL1);
371 	if (enabled)
372 		buf |= RS5C_CTRL1_AALE;
373 	else
374 		buf &= ~RS5C_CTRL1_AALE;
375 
376 	if (i2c_smbus_write_byte_data(client, addr, buf) < 0) {
377 		dev_warn(dev, "can't update alarm\n");
378 		status = -EIO;
379 	} else
380 		rs5c->regs[RS5C_REG_CTRL1] = buf;
381 
382 	return status;
383 }
384 
385 
386 /* NOTE:  Since RTC_WKALM_{RD,SET} were originally defined for EFI,
387  * which only exposes a polled programming interface; and since
388  * these calls map directly to those EFI requests; we don't demand
389  * we have an IRQ for this chip when we go through this API.
390  *
391  * The older x86_pc derived RTC_ALM_{READ,SET} calls require irqs
392  * though, managed through RTC_AIE_{ON,OFF} requests.
393  */
394 
395 static int rs5c_read_alarm(struct device *dev, struct rtc_wkalrm *t)
396 {
397 	struct i2c_client	*client = to_i2c_client(dev);
398 	struct rs5c372		*rs5c = i2c_get_clientdata(client);
399 	int			status;
400 
401 	status = rs5c_get_regs(rs5c);
402 	if (status < 0)
403 		return status;
404 
405 	/* report alarm time */
406 	t->time.tm_sec = 0;
407 	t->time.tm_min = bcd2bin(rs5c->regs[RS5C_REG_ALARM_A_MIN] & 0x7f);
408 	t->time.tm_hour = rs5c_reg2hr(rs5c, rs5c->regs[RS5C_REG_ALARM_A_HOURS]);
409 
410 	/* ... and status */
411 	t->enabled = !!(rs5c->regs[RS5C_REG_CTRL1] & RS5C_CTRL1_AALE);
412 	t->pending = !!(rs5c->regs[RS5C_REG_CTRL2] & RS5C_CTRL2_AAFG);
413 
414 	return 0;
415 }
416 
417 static int rs5c_set_alarm(struct device *dev, struct rtc_wkalrm *t)
418 {
419 	struct i2c_client	*client = to_i2c_client(dev);
420 	struct rs5c372		*rs5c = i2c_get_clientdata(client);
421 	int			status, addr, i;
422 	unsigned char		buf[3];
423 
424 	/* only handle up to 24 hours in the future, like RTC_ALM_SET */
425 	if (t->time.tm_mday != -1
426 			|| t->time.tm_mon != -1
427 			|| t->time.tm_year != -1)
428 		return -EINVAL;
429 
430 	/* REVISIT: round up tm_sec */
431 
432 	/* if needed, disable irq (clears pending status) */
433 	status = rs5c_get_regs(rs5c);
434 	if (status < 0)
435 		return status;
436 	if (rs5c->regs[RS5C_REG_CTRL1] & RS5C_CTRL1_AALE) {
437 		addr = RS5C_ADDR(RS5C_REG_CTRL1);
438 		buf[0] = rs5c->regs[RS5C_REG_CTRL1] & ~RS5C_CTRL1_AALE;
439 		if (i2c_smbus_write_byte_data(client, addr, buf[0]) < 0) {
440 			dev_dbg(dev, "can't disable alarm\n");
441 			return -EIO;
442 		}
443 		rs5c->regs[RS5C_REG_CTRL1] = buf[0];
444 	}
445 
446 	/* set alarm */
447 	buf[0] = bin2bcd(t->time.tm_min);
448 	buf[1] = rs5c_hr2reg(rs5c, t->time.tm_hour);
449 	buf[2] = 0x7f;	/* any/all days */
450 
451 	for (i = 0; i < sizeof(buf); i++) {
452 		addr = RS5C_ADDR(RS5C_REG_ALARM_A_MIN + i);
453 		if (i2c_smbus_write_byte_data(client, addr, buf[i]) < 0) {
454 			dev_dbg(dev, "can't set alarm time\n");
455 			return -EIO;
456 		}
457 	}
458 
459 	/* ... and maybe enable its irq */
460 	if (t->enabled) {
461 		addr = RS5C_ADDR(RS5C_REG_CTRL1);
462 		buf[0] = rs5c->regs[RS5C_REG_CTRL1] | RS5C_CTRL1_AALE;
463 		if (i2c_smbus_write_byte_data(client, addr, buf[0]) < 0)
464 			dev_warn(dev, "can't enable alarm\n");
465 		rs5c->regs[RS5C_REG_CTRL1] = buf[0];
466 	}
467 
468 	return 0;
469 }
470 
471 #if IS_ENABLED(CONFIG_RTC_INTF_PROC)
472 
473 static int rs5c372_rtc_proc(struct device *dev, struct seq_file *seq)
474 {
475 	int err, osc, trim;
476 
477 	err = rs5c372_get_trim(to_i2c_client(dev), &osc, &trim);
478 	if (err == 0) {
479 		seq_printf(seq, "crystal\t\t: %d.%03d KHz\n",
480 				osc / 1000, osc % 1000);
481 		seq_printf(seq, "trim\t\t: %d\n", trim);
482 	}
483 
484 	return 0;
485 }
486 
487 #else
488 #define	rs5c372_rtc_proc	NULL
489 #endif
490 
491 static const struct rtc_class_ops rs5c372_rtc_ops = {
492 	.proc		= rs5c372_rtc_proc,
493 	.read_time	= rs5c372_rtc_read_time,
494 	.set_time	= rs5c372_rtc_set_time,
495 	.read_alarm	= rs5c_read_alarm,
496 	.set_alarm	= rs5c_set_alarm,
497 	.alarm_irq_enable = rs5c_rtc_alarm_irq_enable,
498 };
499 
500 #if IS_ENABLED(CONFIG_RTC_INTF_SYSFS)
501 
502 static ssize_t rs5c372_sysfs_show_trim(struct device *dev,
503 				struct device_attribute *attr, char *buf)
504 {
505 	int err, trim;
506 
507 	err = rs5c372_get_trim(to_i2c_client(dev), NULL, &trim);
508 	if (err)
509 		return err;
510 
511 	return sprintf(buf, "%d\n", trim);
512 }
513 static DEVICE_ATTR(trim, S_IRUGO, rs5c372_sysfs_show_trim, NULL);
514 
515 static ssize_t rs5c372_sysfs_show_osc(struct device *dev,
516 				struct device_attribute *attr, char *buf)
517 {
518 	int err, osc;
519 
520 	err = rs5c372_get_trim(to_i2c_client(dev), &osc, NULL);
521 	if (err)
522 		return err;
523 
524 	return sprintf(buf, "%d.%03d KHz\n", osc / 1000, osc % 1000);
525 }
526 static DEVICE_ATTR(osc, S_IRUGO, rs5c372_sysfs_show_osc, NULL);
527 
528 static int rs5c_sysfs_register(struct device *dev)
529 {
530 	int err;
531 
532 	err = device_create_file(dev, &dev_attr_trim);
533 	if (err)
534 		return err;
535 	err = device_create_file(dev, &dev_attr_osc);
536 	if (err)
537 		device_remove_file(dev, &dev_attr_trim);
538 
539 	return err;
540 }
541 
542 static void rs5c_sysfs_unregister(struct device *dev)
543 {
544 	device_remove_file(dev, &dev_attr_trim);
545 	device_remove_file(dev, &dev_attr_osc);
546 }
547 
548 #else
549 static int rs5c_sysfs_register(struct device *dev)
550 {
551 	return 0;
552 }
553 
554 static void rs5c_sysfs_unregister(struct device *dev)
555 {
556 	/* nothing */
557 }
558 #endif	/* SYSFS */
559 
560 static struct i2c_driver rs5c372_driver;
561 
562 static int rs5c_oscillator_setup(struct rs5c372 *rs5c372)
563 {
564 	unsigned char buf[2];
565 	int addr, i, ret = 0;
566 
567 	addr   = RS5C_ADDR(RS5C_REG_CTRL1);
568 	buf[0] = rs5c372->regs[RS5C_REG_CTRL1];
569 	buf[1] = rs5c372->regs[RS5C_REG_CTRL2];
570 
571 	switch (rs5c372->type) {
572 	case rtc_r2025sd:
573 		if (buf[1] & R2x2x_CTRL2_XSTP)
574 			return ret;
575 		break;
576 	case rtc_r2221tl:
577 		if (!(buf[1] & R2x2x_CTRL2_XSTP))
578 			return ret;
579 		break;
580 	default:
581 		if (!(buf[1] & RS5C_CTRL2_XSTP))
582 			return ret;
583 		break;
584 	}
585 
586 	/* use 24hr mode */
587 	switch (rs5c372->type) {
588 	case rtc_rs5c372a:
589 	case rtc_rs5c372b:
590 		buf[1] |= RS5C372_CTRL2_24;
591 		rs5c372->time24 = 1;
592 		break;
593 	case rtc_r2025sd:
594 	case rtc_r2221tl:
595 	case rtc_rv5c386:
596 	case rtc_rv5c387a:
597 		buf[0] |= RV5C387_CTRL1_24;
598 		rs5c372->time24 = 1;
599 		break;
600 	default:
601 		/* impossible */
602 		break;
603 	}
604 
605 	for (i = 0; i < sizeof(buf); i++) {
606 		addr = RS5C_ADDR(RS5C_REG_CTRL1 + i);
607 		ret = i2c_smbus_write_byte_data(rs5c372->client, addr, buf[i]);
608 		if (unlikely(ret < 0))
609 			return ret;
610 	}
611 
612 	rs5c372->regs[RS5C_REG_CTRL1] = buf[0];
613 	rs5c372->regs[RS5C_REG_CTRL2] = buf[1];
614 
615 	return 0;
616 }
617 
618 static int rs5c372_probe(struct i2c_client *client,
619 			 const struct i2c_device_id *id)
620 {
621 	int err = 0;
622 	int smbus_mode = 0;
623 	struct rs5c372 *rs5c372;
624 
625 	dev_dbg(&client->dev, "%s\n", __func__);
626 
627 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
628 			I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK)) {
629 		/*
630 		 * If we don't have any master mode adapter, try breaking
631 		 * it down in to the barest of capabilities.
632 		 */
633 		if (i2c_check_functionality(client->adapter,
634 				I2C_FUNC_SMBUS_BYTE_DATA |
635 				I2C_FUNC_SMBUS_I2C_BLOCK))
636 			smbus_mode = 1;
637 		else {
638 			/* Still no good, give up */
639 			err = -ENODEV;
640 			goto exit;
641 		}
642 	}
643 
644 	rs5c372 = devm_kzalloc(&client->dev, sizeof(struct rs5c372),
645 				GFP_KERNEL);
646 	if (!rs5c372) {
647 		err = -ENOMEM;
648 		goto exit;
649 	}
650 
651 	rs5c372->client = client;
652 	i2c_set_clientdata(client, rs5c372);
653 	if (client->dev.of_node)
654 		rs5c372->type = (enum rtc_type)
655 			of_device_get_match_data(&client->dev);
656 	else
657 		rs5c372->type = id->driver_data;
658 
659 	/* we read registers 0x0f then 0x00-0x0f; skip the first one */
660 	rs5c372->regs = &rs5c372->buf[1];
661 	rs5c372->smbus = smbus_mode;
662 
663 	err = rs5c_get_regs(rs5c372);
664 	if (err < 0)
665 		goto exit;
666 
667 	/* clock may be set for am/pm or 24 hr time */
668 	switch (rs5c372->type) {
669 	case rtc_rs5c372a:
670 	case rtc_rs5c372b:
671 		/* alarm uses ALARM_A; and nINTRA on 372a, nINTR on 372b.
672 		 * so does periodic irq, except some 327a modes.
673 		 */
674 		if (rs5c372->regs[RS5C_REG_CTRL2] & RS5C372_CTRL2_24)
675 			rs5c372->time24 = 1;
676 		break;
677 	case rtc_r2025sd:
678 	case rtc_r2221tl:
679 	case rtc_rv5c386:
680 	case rtc_rv5c387a:
681 		if (rs5c372->regs[RS5C_REG_CTRL1] & RV5C387_CTRL1_24)
682 			rs5c372->time24 = 1;
683 		/* alarm uses ALARM_W; and nINTRB for alarm and periodic
684 		 * irq, on both 386 and 387
685 		 */
686 		break;
687 	default:
688 		dev_err(&client->dev, "unknown RTC type\n");
689 		goto exit;
690 	}
691 
692 	/* if the oscillator lost power and no other software (like
693 	 * the bootloader) set it up, do it here.
694 	 *
695 	 * The R2025S/D does this a little differently than the other
696 	 * parts, so we special case that..
697 	 */
698 	err = rs5c_oscillator_setup(rs5c372);
699 	if (unlikely(err < 0)) {
700 		dev_err(&client->dev, "setup error\n");
701 		goto exit;
702 	}
703 
704 	dev_info(&client->dev, "%s found, %s\n",
705 			({ char *s; switch (rs5c372->type) {
706 			case rtc_r2025sd:	s = "r2025sd"; break;
707 			case rtc_r2221tl:	s = "r2221tl"; break;
708 			case rtc_rs5c372a:	s = "rs5c372a"; break;
709 			case rtc_rs5c372b:	s = "rs5c372b"; break;
710 			case rtc_rv5c386:	s = "rv5c386"; break;
711 			case rtc_rv5c387a:	s = "rv5c387a"; break;
712 			default:		s = "chip"; break;
713 			}; s;}),
714 			rs5c372->time24 ? "24hr" : "am/pm"
715 			);
716 
717 	/* REVISIT use client->irq to register alarm irq ... */
718 	rs5c372->rtc = devm_rtc_device_register(&client->dev,
719 					rs5c372_driver.driver.name,
720 					&rs5c372_rtc_ops, THIS_MODULE);
721 
722 	if (IS_ERR(rs5c372->rtc)) {
723 		err = PTR_ERR(rs5c372->rtc);
724 		goto exit;
725 	}
726 
727 	err = rs5c_sysfs_register(&client->dev);
728 	if (err)
729 		goto exit;
730 
731 	return 0;
732 
733 exit:
734 	return err;
735 }
736 
737 static int rs5c372_remove(struct i2c_client *client)
738 {
739 	rs5c_sysfs_unregister(&client->dev);
740 	return 0;
741 }
742 
743 static struct i2c_driver rs5c372_driver = {
744 	.driver		= {
745 		.name	= "rtc-rs5c372",
746 		.of_match_table = of_match_ptr(rs5c372_of_match),
747 	},
748 	.probe		= rs5c372_probe,
749 	.remove		= rs5c372_remove,
750 	.id_table	= rs5c372_id,
751 };
752 
753 module_i2c_driver(rs5c372_driver);
754 
755 MODULE_AUTHOR(
756 		"Pavel Mironchik <pmironchik@optifacio.net>, "
757 		"Alessandro Zummo <a.zummo@towertech.it>, "
758 		"Paul Mundt <lethal@linux-sh.org>");
759 MODULE_DESCRIPTION("Ricoh RS5C372 RTC driver");
760 MODULE_LICENSE("GPL");
761