1 /*
2  * An i2c driver for the Xicor/Intersil X1205 RTC
3  * Copyright 2004 Karen Spearel
4  * Copyright 2005 Alessandro Zummo
5  *
6  * please send all reports to:
7  *	Karen Spearel <kas111 at gmail dot com>
8  *	Alessandro Zummo <a.zummo@towertech.it>
9  *
10  * based on a lot of other RTC drivers.
11  *
12  * Information and datasheet:
13  * http://www.intersil.com/cda/deviceinfo/0,1477,X1205,00.html
14  *
15  * This program is free software; you can redistribute it and/or modify
16  * it under the terms of the GNU General Public License version 2 as
17  * published by the Free Software Foundation.
18  */
19 
20 #include <linux/i2c.h>
21 #include <linux/bcd.h>
22 #include <linux/rtc.h>
23 #include <linux/delay.h>
24 #include <linux/module.h>
25 #include <linux/bitops.h>
26 
27 /* offsets into CCR area */
28 
29 #define CCR_SEC			0
30 #define CCR_MIN			1
31 #define CCR_HOUR		2
32 #define CCR_MDAY		3
33 #define CCR_MONTH		4
34 #define CCR_YEAR		5
35 #define CCR_WDAY		6
36 #define CCR_Y2K			7
37 
38 #define X1205_REG_SR		0x3F	/* status register */
39 #define X1205_REG_Y2K		0x37
40 #define X1205_REG_DW		0x36
41 #define X1205_REG_YR		0x35
42 #define X1205_REG_MO		0x34
43 #define X1205_REG_DT		0x33
44 #define X1205_REG_HR		0x32
45 #define X1205_REG_MN		0x31
46 #define X1205_REG_SC		0x30
47 #define X1205_REG_DTR		0x13
48 #define X1205_REG_ATR		0x12
49 #define X1205_REG_INT		0x11
50 #define X1205_REG_0		0x10
51 #define X1205_REG_Y2K1		0x0F
52 #define X1205_REG_DWA1		0x0E
53 #define X1205_REG_YRA1		0x0D
54 #define X1205_REG_MOA1		0x0C
55 #define X1205_REG_DTA1		0x0B
56 #define X1205_REG_HRA1		0x0A
57 #define X1205_REG_MNA1		0x09
58 #define X1205_REG_SCA1		0x08
59 #define X1205_REG_Y2K0		0x07
60 #define X1205_REG_DWA0		0x06
61 #define X1205_REG_YRA0		0x05
62 #define X1205_REG_MOA0		0x04
63 #define X1205_REG_DTA0		0x03
64 #define X1205_REG_HRA0		0x02
65 #define X1205_REG_MNA0		0x01
66 #define X1205_REG_SCA0		0x00
67 
68 #define X1205_CCR_BASE		0x30	/* Base address of CCR */
69 #define X1205_ALM0_BASE		0x00	/* Base address of ALARM0 */
70 
71 #define X1205_SR_RTCF		0x01	/* Clock failure */
72 #define X1205_SR_WEL		0x02	/* Write Enable Latch */
73 #define X1205_SR_RWEL		0x04	/* Register Write Enable */
74 #define X1205_SR_AL0		0x20	/* Alarm 0 match */
75 
76 #define X1205_DTR_DTR0		0x01
77 #define X1205_DTR_DTR1		0x02
78 #define X1205_DTR_DTR2		0x04
79 
80 #define X1205_HR_MIL		0x80	/* Set in ccr.hour for 24 hr mode */
81 
82 #define X1205_INT_AL0E		0x20	/* Alarm 0 enable */
83 
84 static struct i2c_driver x1205_driver;
85 
86 /*
87  * In the routines that deal directly with the x1205 hardware, we use
88  * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch
89  * Epoch is initialized as 2000. Time is set to UTC.
90  */
x1205_get_datetime(struct i2c_client * client,struct rtc_time * tm,unsigned char reg_base)91 static int x1205_get_datetime(struct i2c_client *client, struct rtc_time *tm,
92 				unsigned char reg_base)
93 {
94 	unsigned char dt_addr[2] = { 0, reg_base };
95 	unsigned char buf[8];
96 	int i;
97 
98 	struct i2c_msg msgs[] = {
99 		{/* setup read ptr */
100 			.addr = client->addr,
101 			.len = 2,
102 			.buf = dt_addr
103 		},
104 		{/* read date */
105 			.addr = client->addr,
106 			.flags = I2C_M_RD,
107 			.len = 8,
108 			.buf = buf
109 		},
110 	};
111 
112 	/* read date registers */
113 	if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) {
114 		dev_err(&client->dev, "%s: read error\n", __func__);
115 		return -EIO;
116 	}
117 
118 	dev_dbg(&client->dev,
119 		"%s: raw read data - sec=%02x, min=%02x, hr=%02x, "
120 		"mday=%02x, mon=%02x, year=%02x, wday=%02x, y2k=%02x\n",
121 		__func__,
122 		buf[0], buf[1], buf[2], buf[3],
123 		buf[4], buf[5], buf[6], buf[7]);
124 
125 	/* Mask out the enable bits if these are alarm registers */
126 	if (reg_base < X1205_CCR_BASE)
127 		for (i = 0; i <= 4; i++)
128 			buf[i] &= 0x7F;
129 
130 	tm->tm_sec = bcd2bin(buf[CCR_SEC]);
131 	tm->tm_min = bcd2bin(buf[CCR_MIN]);
132 	tm->tm_hour = bcd2bin(buf[CCR_HOUR] & 0x3F); /* hr is 0-23 */
133 	tm->tm_mday = bcd2bin(buf[CCR_MDAY]);
134 	tm->tm_mon = bcd2bin(buf[CCR_MONTH]) - 1; /* mon is 0-11 */
135 	tm->tm_year = bcd2bin(buf[CCR_YEAR])
136 			+ (bcd2bin(buf[CCR_Y2K]) * 100) - 1900;
137 	tm->tm_wday = buf[CCR_WDAY];
138 
139 	dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
140 		"mday=%d, mon=%d, year=%d, wday=%d\n",
141 		__func__,
142 		tm->tm_sec, tm->tm_min, tm->tm_hour,
143 		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
144 
145 	return 0;
146 }
147 
x1205_get_status(struct i2c_client * client,unsigned char * sr)148 static int x1205_get_status(struct i2c_client *client, unsigned char *sr)
149 {
150 	static unsigned char sr_addr[2] = { 0, X1205_REG_SR };
151 
152 	struct i2c_msg msgs[] = {
153 		{     /* setup read ptr */
154 			.addr = client->addr,
155 			.len = 2,
156 			.buf = sr_addr
157 		},
158 		{    /* read status */
159 			.addr = client->addr,
160 			.flags = I2C_M_RD,
161 			.len = 1,
162 			.buf = sr
163 		},
164 	};
165 
166 	/* read status register */
167 	if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) {
168 		dev_err(&client->dev, "%s: read error\n", __func__);
169 		return -EIO;
170 	}
171 
172 	return 0;
173 }
174 
x1205_set_datetime(struct i2c_client * client,struct rtc_time * tm,u8 reg_base,unsigned char alm_enable)175 static int x1205_set_datetime(struct i2c_client *client, struct rtc_time *tm,
176 			u8 reg_base, unsigned char alm_enable)
177 {
178 	int i, xfer;
179 	unsigned char rdata[10] = { 0, reg_base };
180 	unsigned char *buf = rdata + 2;
181 
182 	static const unsigned char wel[3] = { 0, X1205_REG_SR,
183 						X1205_SR_WEL };
184 
185 	static const unsigned char rwel[3] = { 0, X1205_REG_SR,
186 						X1205_SR_WEL | X1205_SR_RWEL };
187 
188 	static const unsigned char diswe[3] = { 0, X1205_REG_SR, 0 };
189 
190 	dev_dbg(&client->dev,
191 		"%s: sec=%d min=%d hour=%d mday=%d mon=%d year=%d wday=%d\n",
192 		__func__, tm->tm_sec, tm->tm_min, tm->tm_hour, tm->tm_mday,
193 		tm->tm_mon, tm->tm_year, tm->tm_wday);
194 
195 	buf[CCR_SEC] = bin2bcd(tm->tm_sec);
196 	buf[CCR_MIN] = bin2bcd(tm->tm_min);
197 
198 	/* set hour and 24hr bit */
199 	buf[CCR_HOUR] = bin2bcd(tm->tm_hour) | X1205_HR_MIL;
200 
201 	buf[CCR_MDAY] = bin2bcd(tm->tm_mday);
202 
203 	/* month, 1 - 12 */
204 	buf[CCR_MONTH] = bin2bcd(tm->tm_mon + 1);
205 
206 	/* year, since the rtc epoch*/
207 	buf[CCR_YEAR] = bin2bcd(tm->tm_year % 100);
208 	buf[CCR_WDAY] = tm->tm_wday & 0x07;
209 	buf[CCR_Y2K] = bin2bcd((tm->tm_year + 1900) / 100);
210 
211 	/* If writing alarm registers, set compare bits on registers 0-4 */
212 	if (reg_base < X1205_CCR_BASE)
213 		for (i = 0; i <= 4; i++)
214 			buf[i] |= 0x80;
215 
216 	/* this sequence is required to unlock the chip */
217 	xfer = i2c_master_send(client, wel, 3);
218 	if (xfer != 3) {
219 		dev_err(&client->dev, "%s: wel - %d\n", __func__, xfer);
220 		return -EIO;
221 	}
222 
223 	xfer = i2c_master_send(client, rwel, 3);
224 	if (xfer != 3) {
225 		dev_err(&client->dev, "%s: rwel - %d\n", __func__, xfer);
226 		return -EIO;
227 	}
228 
229 	xfer = i2c_master_send(client, rdata, sizeof(rdata));
230 	if (xfer != sizeof(rdata)) {
231 		dev_err(&client->dev,
232 			"%s: result=%d addr=%02x, data=%02x\n",
233 			__func__,
234 			 xfer, rdata[1], rdata[2]);
235 		return -EIO;
236 	}
237 
238 	/* If we wrote to the nonvolatile region, wait 10msec for write cycle*/
239 	if (reg_base < X1205_CCR_BASE) {
240 		unsigned char al0e[3] = { 0, X1205_REG_INT, 0 };
241 
242 		msleep(10);
243 
244 		/* ...and set or clear the AL0E bit in the INT register */
245 
246 		/* Need to set RWEL again as the write has cleared it */
247 		xfer = i2c_master_send(client, rwel, 3);
248 		if (xfer != 3) {
249 			dev_err(&client->dev,
250 				"%s: aloe rwel - %d\n",
251 				__func__,
252 				xfer);
253 			return -EIO;
254 		}
255 
256 		if (alm_enable)
257 			al0e[2] = X1205_INT_AL0E;
258 
259 		xfer = i2c_master_send(client, al0e, 3);
260 		if (xfer != 3) {
261 			dev_err(&client->dev,
262 				"%s: al0e - %d\n",
263 				__func__,
264 				xfer);
265 			return -EIO;
266 		}
267 
268 		/* and wait 10msec again for this write to complete */
269 		msleep(10);
270 	}
271 
272 	/* disable further writes */
273 	xfer = i2c_master_send(client, diswe, 3);
274 	if (xfer != 3) {
275 		dev_err(&client->dev, "%s: diswe - %d\n", __func__, xfer);
276 		return -EIO;
277 	}
278 
279 	return 0;
280 }
281 
x1205_fix_osc(struct i2c_client * client)282 static int x1205_fix_osc(struct i2c_client *client)
283 {
284 	int err;
285 	struct rtc_time tm;
286 
287 	memset(&tm, 0, sizeof(tm));
288 
289 	err = x1205_set_datetime(client, &tm, X1205_CCR_BASE, 0);
290 	if (err < 0)
291 		dev_err(&client->dev, "unable to restart the oscillator\n");
292 
293 	return err;
294 }
295 
x1205_get_dtrim(struct i2c_client * client,int * trim)296 static int x1205_get_dtrim(struct i2c_client *client, int *trim)
297 {
298 	unsigned char dtr;
299 	static unsigned char dtr_addr[2] = { 0, X1205_REG_DTR };
300 
301 	struct i2c_msg msgs[] = {
302 		{	/* setup read ptr */
303 			.addr = client->addr,
304 			.len = 2,
305 			.buf = dtr_addr
306 		},
307 		{      /* read dtr */
308 			.addr = client->addr,
309 			.flags = I2C_M_RD,
310 			.len = 1,
311 			.buf = &dtr
312 		},
313 	};
314 
315 	/* read dtr register */
316 	if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) {
317 		dev_err(&client->dev, "%s: read error\n", __func__);
318 		return -EIO;
319 	}
320 
321 	dev_dbg(&client->dev, "%s: raw dtr=%x\n", __func__, dtr);
322 
323 	*trim = 0;
324 
325 	if (dtr & X1205_DTR_DTR0)
326 		*trim += 20;
327 
328 	if (dtr & X1205_DTR_DTR1)
329 		*trim += 10;
330 
331 	if (dtr & X1205_DTR_DTR2)
332 		*trim = -*trim;
333 
334 	return 0;
335 }
336 
x1205_get_atrim(struct i2c_client * client,int * trim)337 static int x1205_get_atrim(struct i2c_client *client, int *trim)
338 {
339 	s8 atr;
340 	static unsigned char atr_addr[2] = { 0, X1205_REG_ATR };
341 
342 	struct i2c_msg msgs[] = {
343 		{/* setup read ptr */
344 			.addr = client->addr,
345 			.len = 2,
346 			.buf = atr_addr
347 		},
348 		{/* read atr */
349 			.addr = client->addr,
350 			.flags = I2C_M_RD,
351 			.len = 1,
352 			.buf = &atr
353 		},
354 	};
355 
356 	/* read atr register */
357 	if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) {
358 		dev_err(&client->dev, "%s: read error\n", __func__);
359 		return -EIO;
360 	}
361 
362 	dev_dbg(&client->dev, "%s: raw atr=%x\n", __func__, atr);
363 
364 	/* atr is a two's complement value on 6 bits,
365 	 * perform sign extension. The formula is
366 	 * Catr = (atr * 0.25pF) + 11.00pF.
367 	 */
368 	atr = sign_extend32(atr, 5);
369 
370 	dev_dbg(&client->dev, "%s: raw atr=%x (%d)\n", __func__, atr, atr);
371 
372 	*trim = (atr * 250) + 11000;
373 
374 	dev_dbg(&client->dev, "%s: real=%d\n", __func__, *trim);
375 
376 	return 0;
377 }
378 
379 struct x1205_limit {
380 	unsigned char reg, mask, min, max;
381 };
382 
x1205_validate_client(struct i2c_client * client)383 static int x1205_validate_client(struct i2c_client *client)
384 {
385 	int i, xfer;
386 
387 	/* Probe array. We will read the register at the specified
388 	 * address and check if the given bits are zero.
389 	 */
390 	static const unsigned char probe_zero_pattern[] = {
391 		/* register, mask */
392 		X1205_REG_SR,	0x18,
393 		X1205_REG_DTR,	0xF8,
394 		X1205_REG_ATR,	0xC0,
395 		X1205_REG_INT,	0x18,
396 		X1205_REG_0,	0xFF,
397 	};
398 
399 	static const struct x1205_limit probe_limits_pattern[] = {
400 		/* register, mask, min, max */
401 		{ X1205_REG_Y2K,	0xFF,	19,	20	},
402 		{ X1205_REG_DW,		0xFF,	0,	6	},
403 		{ X1205_REG_YR,		0xFF,	0,	99	},
404 		{ X1205_REG_MO,		0xFF,	0,	12	},
405 		{ X1205_REG_DT,		0xFF,	0,	31	},
406 		{ X1205_REG_HR,		0x7F,	0,	23	},
407 		{ X1205_REG_MN,		0xFF,	0,	59	},
408 		{ X1205_REG_SC,		0xFF,	0,	59	},
409 		{ X1205_REG_Y2K1,	0xFF,	19,	20	},
410 		{ X1205_REG_Y2K0,	0xFF,	19,	20	},
411 	};
412 
413 	/* check that registers have bits a 0 where expected */
414 	for (i = 0; i < ARRAY_SIZE(probe_zero_pattern); i += 2) {
415 		unsigned char buf;
416 
417 		unsigned char addr[2] = { 0, probe_zero_pattern[i] };
418 
419 		struct i2c_msg msgs[2] = {
420 			{
421 				.addr = client->addr,
422 				.len = 2,
423 				.buf = addr
424 			},
425 			{
426 				.addr = client->addr,
427 				.flags = I2C_M_RD,
428 				.len = 1,
429 				.buf = &buf
430 			},
431 		};
432 
433 		xfer = i2c_transfer(client->adapter, msgs, 2);
434 		if (xfer != 2) {
435 			dev_err(&client->dev,
436 				"%s: could not read register %x\n",
437 				__func__, probe_zero_pattern[i]);
438 
439 			return -EIO;
440 		}
441 
442 		if ((buf & probe_zero_pattern[i+1]) != 0) {
443 			dev_err(&client->dev,
444 				"%s: register=%02x, zero pattern=%d, value=%x\n",
445 				__func__, probe_zero_pattern[i], i, buf);
446 
447 			return -ENODEV;
448 		}
449 	}
450 
451 	/* check limits (only registers with bcd values) */
452 	for (i = 0; i < ARRAY_SIZE(probe_limits_pattern); i++) {
453 		unsigned char reg, value;
454 
455 		unsigned char addr[2] = { 0, probe_limits_pattern[i].reg };
456 
457 		struct i2c_msg msgs[2] = {
458 			{
459 				.addr = client->addr,
460 				.len = 2,
461 				.buf = addr
462 			},
463 			{
464 				.addr = client->addr,
465 				.flags = I2C_M_RD,
466 				.len = 1,
467 				.buf = &reg
468 			},
469 		};
470 
471 		xfer = i2c_transfer(client->adapter, msgs, 2);
472 		if (xfer != 2) {
473 			dev_err(&client->dev,
474 				"%s: could not read register %x\n",
475 				__func__, probe_limits_pattern[i].reg);
476 
477 			return -EIO;
478 		}
479 
480 		value = bcd2bin(reg & probe_limits_pattern[i].mask);
481 
482 		if (value > probe_limits_pattern[i].max ||
483 			value < probe_limits_pattern[i].min) {
484 			dev_dbg(&client->dev,
485 				"%s: register=%x, lim pattern=%d, value=%d\n",
486 				__func__, probe_limits_pattern[i].reg,
487 				i, value);
488 
489 			return -ENODEV;
490 		}
491 	}
492 
493 	return 0;
494 }
495 
x1205_rtc_read_alarm(struct device * dev,struct rtc_wkalrm * alrm)496 static int x1205_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
497 {
498 	int err;
499 	unsigned char intreg, status;
500 	static unsigned char int_addr[2] = { 0, X1205_REG_INT };
501 	struct i2c_client *client = to_i2c_client(dev);
502 	struct i2c_msg msgs[] = {
503 		{ /* setup read ptr */
504 			.addr = client->addr,
505 			.len = 2,
506 			.buf = int_addr
507 		},
508 		{/* read INT register */
509 
510 			.addr = client->addr,
511 			.flags = I2C_M_RD,
512 			.len = 1,
513 			.buf = &intreg
514 		},
515 	};
516 
517 	/* read interrupt register and status register */
518 	if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) {
519 		dev_err(&client->dev, "%s: read error\n", __func__);
520 		return -EIO;
521 	}
522 	err = x1205_get_status(client, &status);
523 	if (err == 0) {
524 		alrm->pending = (status & X1205_SR_AL0) ? 1 : 0;
525 		alrm->enabled = (intreg & X1205_INT_AL0E) ? 1 : 0;
526 		err = x1205_get_datetime(client, &alrm->time, X1205_ALM0_BASE);
527 	}
528 	return err;
529 }
530 
x1205_rtc_set_alarm(struct device * dev,struct rtc_wkalrm * alrm)531 static int x1205_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
532 {
533 	return x1205_set_datetime(to_i2c_client(dev),
534 		&alrm->time, X1205_ALM0_BASE, alrm->enabled);
535 }
536 
x1205_rtc_read_time(struct device * dev,struct rtc_time * tm)537 static int x1205_rtc_read_time(struct device *dev, struct rtc_time *tm)
538 {
539 	return x1205_get_datetime(to_i2c_client(dev),
540 		tm, X1205_CCR_BASE);
541 }
542 
x1205_rtc_set_time(struct device * dev,struct rtc_time * tm)543 static int x1205_rtc_set_time(struct device *dev, struct rtc_time *tm)
544 {
545 	return x1205_set_datetime(to_i2c_client(dev),
546 		tm, X1205_CCR_BASE, 0);
547 }
548 
x1205_rtc_proc(struct device * dev,struct seq_file * seq)549 static int x1205_rtc_proc(struct device *dev, struct seq_file *seq)
550 {
551 	int err, dtrim, atrim;
552 
553 	err = x1205_get_dtrim(to_i2c_client(dev), &dtrim);
554 	if (!err)
555 		seq_printf(seq, "digital_trim\t: %d ppm\n", dtrim);
556 
557 	err = x1205_get_atrim(to_i2c_client(dev), &atrim);
558 	if (!err)
559 		seq_printf(seq, "analog_trim\t: %d.%02d pF\n",
560 			atrim / 1000, atrim % 1000);
561 	return 0;
562 }
563 
564 static const struct rtc_class_ops x1205_rtc_ops = {
565 	.proc		= x1205_rtc_proc,
566 	.read_time	= x1205_rtc_read_time,
567 	.set_time	= x1205_rtc_set_time,
568 	.read_alarm	= x1205_rtc_read_alarm,
569 	.set_alarm	= x1205_rtc_set_alarm,
570 };
571 
x1205_sysfs_show_atrim(struct device * dev,struct device_attribute * attr,char * buf)572 static ssize_t x1205_sysfs_show_atrim(struct device *dev,
573 				struct device_attribute *attr, char *buf)
574 {
575 	int err, atrim;
576 
577 	err = x1205_get_atrim(to_i2c_client(dev), &atrim);
578 	if (err)
579 		return err;
580 
581 	return sprintf(buf, "%d.%02d pF\n", atrim / 1000, atrim % 1000);
582 }
583 static DEVICE_ATTR(atrim, S_IRUGO, x1205_sysfs_show_atrim, NULL);
584 
x1205_sysfs_show_dtrim(struct device * dev,struct device_attribute * attr,char * buf)585 static ssize_t x1205_sysfs_show_dtrim(struct device *dev,
586 				struct device_attribute *attr, char *buf)
587 {
588 	int err, dtrim;
589 
590 	err = x1205_get_dtrim(to_i2c_client(dev), &dtrim);
591 	if (err)
592 		return err;
593 
594 	return sprintf(buf, "%d ppm\n", dtrim);
595 }
596 static DEVICE_ATTR(dtrim, S_IRUGO, x1205_sysfs_show_dtrim, NULL);
597 
x1205_sysfs_register(struct device * dev)598 static int x1205_sysfs_register(struct device *dev)
599 {
600 	int err;
601 
602 	err = device_create_file(dev, &dev_attr_atrim);
603 	if (err)
604 		return err;
605 
606 	err = device_create_file(dev, &dev_attr_dtrim);
607 	if (err)
608 		device_remove_file(dev, &dev_attr_atrim);
609 
610 	return err;
611 }
612 
x1205_sysfs_unregister(struct device * dev)613 static void x1205_sysfs_unregister(struct device *dev)
614 {
615 	device_remove_file(dev, &dev_attr_atrim);
616 	device_remove_file(dev, &dev_attr_dtrim);
617 }
618 
619 
x1205_probe(struct i2c_client * client,const struct i2c_device_id * id)620 static int x1205_probe(struct i2c_client *client,
621 			const struct i2c_device_id *id)
622 {
623 	int err = 0;
624 	unsigned char sr;
625 	struct rtc_device *rtc;
626 
627 	dev_dbg(&client->dev, "%s\n", __func__);
628 
629 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
630 		return -ENODEV;
631 
632 	if (x1205_validate_client(client) < 0)
633 		return -ENODEV;
634 
635 	rtc = devm_rtc_device_register(&client->dev, x1205_driver.driver.name,
636 					&x1205_rtc_ops, THIS_MODULE);
637 
638 	if (IS_ERR(rtc))
639 		return PTR_ERR(rtc);
640 
641 	i2c_set_clientdata(client, rtc);
642 
643 	/* Check for power failures and eventually enable the osc */
644 	err = x1205_get_status(client, &sr);
645 	if (!err) {
646 		if (sr & X1205_SR_RTCF) {
647 			dev_err(&client->dev,
648 				"power failure detected, "
649 				"please set the clock\n");
650 			udelay(50);
651 			x1205_fix_osc(client);
652 		}
653 	} else {
654 		dev_err(&client->dev, "couldn't read status\n");
655 	}
656 
657 	err = x1205_sysfs_register(&client->dev);
658 	if (err)
659 		dev_err(&client->dev, "Unable to create sysfs entries\n");
660 
661 	return 0;
662 }
663 
x1205_remove(struct i2c_client * client)664 static int x1205_remove(struct i2c_client *client)
665 {
666 	x1205_sysfs_unregister(&client->dev);
667 	return 0;
668 }
669 
670 static const struct i2c_device_id x1205_id[] = {
671 	{ "x1205", 0 },
672 	{ }
673 };
674 MODULE_DEVICE_TABLE(i2c, x1205_id);
675 
676 static struct i2c_driver x1205_driver = {
677 	.driver		= {
678 		.name	= "rtc-x1205",
679 	},
680 	.probe		= x1205_probe,
681 	.remove		= x1205_remove,
682 	.id_table	= x1205_id,
683 };
684 
685 module_i2c_driver(x1205_driver);
686 
687 MODULE_AUTHOR(
688 	"Karen Spearel <kas111 at gmail dot com>, "
689 	"Alessandro Zummo <a.zummo@towertech.it>");
690 MODULE_DESCRIPTION("Xicor/Intersil X1205 RTC driver");
691 MODULE_LICENSE("GPL");
692