2 * An i2c driver for the Xicor/Intersil X1205 RTC
3 * Copyright 2004 Karen Spearel
4 * Copyright 2005 Alessandro Zummo
6 * please send all reports to:
7 * Karen Spearel <kas111 at gmail dot com>
8 * Alessandro Zummo <a.zummo@towertech.it>
10 * based on a lot of other RTC drivers.
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License version 2 as
14 * published by the Free Software Foundation.
17 #include <linux/i2c.h>
18 #include <linux/bcd.h>
19 #include <linux/rtc.h>
20 #include <linux/delay.h>
22 #define DRV_VERSION "1.0.7"
24 /* Addresses to scan: none. This chip is located at
25 * 0x6f and uses a two bytes register addressing.
26 * Two bytes need to be written to read a single register,
27 * while most other chips just require one and take the second
28 * one as the data to be written. To prevent corrupting
29 * unknown chips, the user must explicitely set the probe parameter.
32 static unsigned short normal_i2c[] = { I2C_CLIENT_END };
34 /* Insmod parameters */
37 /* offsets into CCR area */
48 #define X1205_REG_SR 0x3F /* status register */
49 #define X1205_REG_Y2K 0x37
50 #define X1205_REG_DW 0x36
51 #define X1205_REG_YR 0x35
52 #define X1205_REG_MO 0x34
53 #define X1205_REG_DT 0x33
54 #define X1205_REG_HR 0x32
55 #define X1205_REG_MN 0x31
56 #define X1205_REG_SC 0x30
57 #define X1205_REG_DTR 0x13
58 #define X1205_REG_ATR 0x12
59 #define X1205_REG_INT 0x11
60 #define X1205_REG_0 0x10
61 #define X1205_REG_Y2K1 0x0F
62 #define X1205_REG_DWA1 0x0E
63 #define X1205_REG_YRA1 0x0D
64 #define X1205_REG_MOA1 0x0C
65 #define X1205_REG_DTA1 0x0B
66 #define X1205_REG_HRA1 0x0A
67 #define X1205_REG_MNA1 0x09
68 #define X1205_REG_SCA1 0x08
69 #define X1205_REG_Y2K0 0x07
70 #define X1205_REG_DWA0 0x06
71 #define X1205_REG_YRA0 0x05
72 #define X1205_REG_MOA0 0x04
73 #define X1205_REG_DTA0 0x03
74 #define X1205_REG_HRA0 0x02
75 #define X1205_REG_MNA0 0x01
76 #define X1205_REG_SCA0 0x00
78 #define X1205_CCR_BASE 0x30 /* Base address of CCR */
79 #define X1205_ALM0_BASE 0x00 /* Base address of ALARM0 */
81 #define X1205_SR_RTCF 0x01 /* Clock failure */
82 #define X1205_SR_WEL 0x02 /* Write Enable Latch */
83 #define X1205_SR_RWEL 0x04 /* Register Write Enable */
85 #define X1205_DTR_DTR0 0x01
86 #define X1205_DTR_DTR1 0x02
87 #define X1205_DTR_DTR2 0x04
89 #define X1205_HR_MIL 0x80 /* Set in ccr.hour for 24 hr mode */
92 static int x1205_attach(struct i2c_adapter *adapter);
93 static int x1205_detach(struct i2c_client *client);
94 static int x1205_probe(struct i2c_adapter *adapter, int address, int kind);
96 static struct i2c_driver x1205_driver = {
100 .id = I2C_DRIVERID_X1205,
101 .attach_adapter = &x1205_attach,
102 .detach_client = &x1205_detach,
106 * In the routines that deal directly with the x1205 hardware, we use
107 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch
108 * Epoch is initialized as 2000. Time is set to UTC.
110 static int x1205_get_datetime(struct i2c_client *client, struct rtc_time *tm,
111 unsigned char reg_base)
113 unsigned char dt_addr[2] = { 0, reg_base };
115 unsigned char buf[8];
117 struct i2c_msg msgs[] = {
118 { client->addr, 0, 2, dt_addr }, /* setup read ptr */
119 { client->addr, I2C_M_RD, 8, buf }, /* read date */
122 /* read date registers */
123 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
124 dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
128 dev_dbg(&client->dev,
129 "%s: raw read data - sec=%02x, min=%02x, hr=%02x, "
130 "mday=%02x, mon=%02x, year=%02x, wday=%02x, y2k=%02x\n",
132 buf[0], buf[1], buf[2], buf[3],
133 buf[4], buf[5], buf[6], buf[7]);
135 tm->tm_sec = BCD2BIN(buf[CCR_SEC]);
136 tm->tm_min = BCD2BIN(buf[CCR_MIN]);
137 tm->tm_hour = BCD2BIN(buf[CCR_HOUR] & 0x3F); /* hr is 0-23 */
138 tm->tm_mday = BCD2BIN(buf[CCR_MDAY]);
139 tm->tm_mon = BCD2BIN(buf[CCR_MONTH]) - 1; /* mon is 0-11 */
140 tm->tm_year = BCD2BIN(buf[CCR_YEAR])
141 + (BCD2BIN(buf[CCR_Y2K]) * 100) - 1900;
142 tm->tm_wday = buf[CCR_WDAY];
144 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
145 "mday=%d, mon=%d, year=%d, wday=%d\n",
147 tm->tm_sec, tm->tm_min, tm->tm_hour,
148 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
153 static int x1205_get_status(struct i2c_client *client, unsigned char *sr)
155 static unsigned char sr_addr[2] = { 0, X1205_REG_SR };
157 struct i2c_msg msgs[] = {
158 { client->addr, 0, 2, sr_addr }, /* setup read ptr */
159 { client->addr, I2C_M_RD, 1, sr }, /* read status */
162 /* read status register */
163 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
164 dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
171 static int x1205_set_datetime(struct i2c_client *client, struct rtc_time *tm,
172 int datetoo, u8 reg_base)
175 unsigned char buf[8];
177 static const unsigned char wel[3] = { 0, X1205_REG_SR,
180 static const unsigned char rwel[3] = { 0, X1205_REG_SR,
181 X1205_SR_WEL | X1205_SR_RWEL };
183 static const unsigned char diswe[3] = { 0, X1205_REG_SR, 0 };
185 dev_dbg(&client->dev,
186 "%s: secs=%d, mins=%d, hours=%d\n",
188 tm->tm_sec, tm->tm_min, tm->tm_hour);
190 buf[CCR_SEC] = BIN2BCD(tm->tm_sec);
191 buf[CCR_MIN] = BIN2BCD(tm->tm_min);
193 /* set hour and 24hr bit */
194 buf[CCR_HOUR] = BIN2BCD(tm->tm_hour) | X1205_HR_MIL;
196 /* should we also set the date? */
198 dev_dbg(&client->dev,
199 "%s: mday=%d, mon=%d, year=%d, wday=%d\n",
201 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
203 buf[CCR_MDAY] = BIN2BCD(tm->tm_mday);
206 buf[CCR_MONTH] = BIN2BCD(tm->tm_mon + 1);
208 /* year, since the rtc epoch*/
209 buf[CCR_YEAR] = BIN2BCD(tm->tm_year % 100);
210 buf[CCR_WDAY] = tm->tm_wday & 0x07;
211 buf[CCR_Y2K] = BIN2BCD(tm->tm_year / 100);
214 /* this sequence is required to unlock the chip */
215 if ((xfer = i2c_master_send(client, wel, 3)) != 3) {
216 dev_err(&client->dev, "%s: wel - %d\n", __FUNCTION__, xfer);
220 if ((xfer = i2c_master_send(client, rwel, 3)) != 3) {
221 dev_err(&client->dev, "%s: rwel - %d\n", __FUNCTION__, xfer);
225 /* write register's data */
226 for (i = 0; i < (datetoo ? 8 : 3); i++) {
227 unsigned char rdata[3] = { 0, reg_base + i, buf[i] };
229 xfer = i2c_master_send(client, rdata, 3);
231 dev_err(&client->dev,
232 "%s: xfer=%d addr=%02x, data=%02x\n",
234 xfer, rdata[1], rdata[2]);
239 /* disable further writes */
240 if ((xfer = i2c_master_send(client, diswe, 3)) != 3) {
241 dev_err(&client->dev, "%s: diswe - %d\n", __FUNCTION__, xfer);
248 static int x1205_fix_osc(struct i2c_client *client)
253 tm.tm_hour = tm.tm_min = tm.tm_sec = 0;
255 if ((err = x1205_set_datetime(client, &tm, 0, X1205_CCR_BASE)) < 0)
256 dev_err(&client->dev,
257 "unable to restart the oscillator\n");
262 static int x1205_get_dtrim(struct i2c_client *client, int *trim)
265 static unsigned char dtr_addr[2] = { 0, X1205_REG_DTR };
267 struct i2c_msg msgs[] = {
268 { client->addr, 0, 2, dtr_addr }, /* setup read ptr */
269 { client->addr, I2C_M_RD, 1, &dtr }, /* read dtr */
272 /* read dtr register */
273 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
274 dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
278 dev_dbg(&client->dev, "%s: raw dtr=%x\n", __FUNCTION__, dtr);
282 if (dtr & X1205_DTR_DTR0)
285 if (dtr & X1205_DTR_DTR1)
288 if (dtr & X1205_DTR_DTR2)
294 static int x1205_get_atrim(struct i2c_client *client, int *trim)
297 static unsigned char atr_addr[2] = { 0, X1205_REG_ATR };
299 struct i2c_msg msgs[] = {
300 { client->addr, 0, 2, atr_addr }, /* setup read ptr */
301 { client->addr, I2C_M_RD, 1, &atr }, /* read atr */
304 /* read atr register */
305 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
306 dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
310 dev_dbg(&client->dev, "%s: raw atr=%x\n", __FUNCTION__, atr);
312 /* atr is a two's complement value on 6 bits,
313 * perform sign extension. The formula is
314 * Catr = (atr * 0.25pF) + 11.00pF.
319 dev_dbg(&client->dev, "%s: raw atr=%x (%d)\n", __FUNCTION__, atr, atr);
321 *trim = (atr * 250) + 11000;
323 dev_dbg(&client->dev, "%s: real=%d\n", __FUNCTION__, *trim);
330 unsigned char reg, mask, min, max;
333 static int x1205_validate_client(struct i2c_client *client)
337 /* Probe array. We will read the register at the specified
338 * address and check if the given bits are zero.
340 static const unsigned char probe_zero_pattern[] = {
349 static const struct x1205_limit probe_limits_pattern[] = {
350 /* register, mask, min, max */
351 { X1205_REG_Y2K, 0xFF, 19, 20 },
352 { X1205_REG_DW, 0xFF, 0, 6 },
353 { X1205_REG_YR, 0xFF, 0, 99 },
354 { X1205_REG_MO, 0xFF, 0, 12 },
355 { X1205_REG_DT, 0xFF, 0, 31 },
356 { X1205_REG_HR, 0x7F, 0, 23 },
357 { X1205_REG_MN, 0xFF, 0, 59 },
358 { X1205_REG_SC, 0xFF, 0, 59 },
359 { X1205_REG_Y2K1, 0xFF, 19, 20 },
360 { X1205_REG_Y2K0, 0xFF, 19, 20 },
363 /* check that registers have bits a 0 where expected */
364 for (i = 0; i < ARRAY_SIZE(probe_zero_pattern); i += 2) {
367 unsigned char addr[2] = { 0, probe_zero_pattern[i] };
369 struct i2c_msg msgs[2] = {
370 { client->addr, 0, 2, addr },
371 { client->addr, I2C_M_RD, 1, &buf },
374 if ((xfer = i2c_transfer(client->adapter, msgs, 2)) != 2) {
375 dev_err(&client->dev,
376 "%s: could not read register %x\n",
377 __FUNCTION__, probe_zero_pattern[i]);
382 if ((buf & probe_zero_pattern[i+1]) != 0) {
383 dev_err(&client->dev,
384 "%s: register=%02x, zero pattern=%d, value=%x\n",
385 __FUNCTION__, probe_zero_pattern[i], i, buf);
391 /* check limits (only registers with bcd values) */
392 for (i = 0; i < ARRAY_SIZE(probe_limits_pattern); i++) {
393 unsigned char reg, value;
395 unsigned char addr[2] = { 0, probe_limits_pattern[i].reg };
397 struct i2c_msg msgs[2] = {
398 { client->addr, 0, 2, addr },
399 { client->addr, I2C_M_RD, 1, ® },
402 if ((xfer = i2c_transfer(client->adapter, msgs, 2)) != 2) {
403 dev_err(&client->dev,
404 "%s: could not read register %x\n",
405 __FUNCTION__, probe_limits_pattern[i].reg);
410 value = BCD2BIN(reg & probe_limits_pattern[i].mask);
412 if (value > probe_limits_pattern[i].max ||
413 value < probe_limits_pattern[i].min) {
414 dev_dbg(&client->dev,
415 "%s: register=%x, lim pattern=%d, value=%d\n",
416 __FUNCTION__, probe_limits_pattern[i].reg,
426 static int x1205_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
428 return x1205_get_datetime(to_i2c_client(dev),
429 &alrm->time, X1205_ALM0_BASE);
432 static int x1205_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
434 return x1205_set_datetime(to_i2c_client(dev),
435 &alrm->time, 1, X1205_ALM0_BASE);
438 static int x1205_rtc_read_time(struct device *dev, struct rtc_time *tm)
440 return x1205_get_datetime(to_i2c_client(dev),
444 static int x1205_rtc_set_time(struct device *dev, struct rtc_time *tm)
446 return x1205_set_datetime(to_i2c_client(dev),
447 tm, 1, X1205_CCR_BASE);
450 static int x1205_rtc_proc(struct device *dev, struct seq_file *seq)
452 int err, dtrim, atrim;
454 if ((err = x1205_get_dtrim(to_i2c_client(dev), &dtrim)) == 0)
455 seq_printf(seq, "digital_trim\t: %d ppm\n", dtrim);
457 if ((err = x1205_get_atrim(to_i2c_client(dev), &atrim)) == 0)
458 seq_printf(seq, "analog_trim\t: %d.%02d pF\n",
459 atrim / 1000, atrim % 1000);
463 static const struct rtc_class_ops x1205_rtc_ops = {
464 .proc = x1205_rtc_proc,
465 .read_time = x1205_rtc_read_time,
466 .set_time = x1205_rtc_set_time,
467 .read_alarm = x1205_rtc_read_alarm,
468 .set_alarm = x1205_rtc_set_alarm,
471 static ssize_t x1205_sysfs_show_atrim(struct device *dev,
472 struct device_attribute *attr, char *buf)
476 err = x1205_get_atrim(to_i2c_client(dev), &atrim);
480 return sprintf(buf, "%d.%02d pF\n", atrim / 1000, atrim % 1000);
482 static DEVICE_ATTR(atrim, S_IRUGO, x1205_sysfs_show_atrim, NULL);
484 static ssize_t x1205_sysfs_show_dtrim(struct device *dev,
485 struct device_attribute *attr, char *buf)
489 err = x1205_get_dtrim(to_i2c_client(dev), &dtrim);
493 return sprintf(buf, "%d ppm\n", dtrim);
495 static DEVICE_ATTR(dtrim, S_IRUGO, x1205_sysfs_show_dtrim, NULL);
497 static int x1205_attach(struct i2c_adapter *adapter)
499 return i2c_probe(adapter, &addr_data, x1205_probe);
502 static int x1205_probe(struct i2c_adapter *adapter, int address, int kind)
506 struct i2c_client *client;
507 struct rtc_device *rtc;
509 dev_dbg(adapter->class_dev.dev, "%s\n", __FUNCTION__);
511 if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) {
516 if (!(client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL))) {
522 client->addr = address;
523 client->driver = &x1205_driver;
524 client->adapter = adapter;
526 strlcpy(client->name, x1205_driver.driver.name, I2C_NAME_SIZE);
528 /* Verify the chip is really an X1205 */
530 if (x1205_validate_client(client) < 0) {
536 /* Inform the i2c layer */
537 if ((err = i2c_attach_client(client)))
540 dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
542 rtc = rtc_device_register(x1205_driver.driver.name, &client->dev,
543 &x1205_rtc_ops, THIS_MODULE);
550 i2c_set_clientdata(client, rtc);
552 /* Check for power failures and eventualy enable the osc */
553 if ((err = x1205_get_status(client, &sr)) == 0) {
554 if (sr & X1205_SR_RTCF) {
555 dev_err(&client->dev,
556 "power failure detected, "
557 "please set the clock\n");
559 x1205_fix_osc(client);
563 dev_err(&client->dev, "couldn't read status\n");
565 err = device_create_file(&client->dev, &dev_attr_atrim);
566 if (err) goto exit_devreg;
567 err = device_create_file(&client->dev, &dev_attr_dtrim);
568 if (err) goto exit_atrim;
573 device_remove_file(&client->dev, &dev_attr_atrim);
576 rtc_device_unregister(rtc);
579 i2c_detach_client(client);
588 static int x1205_detach(struct i2c_client *client)
591 struct rtc_device *rtc = i2c_get_clientdata(client);
594 rtc_device_unregister(rtc);
596 if ((err = i2c_detach_client(client)))
604 static int __init x1205_init(void)
606 return i2c_add_driver(&x1205_driver);
609 static void __exit x1205_exit(void)
611 i2c_del_driver(&x1205_driver);
615 "Karen Spearel <kas111 at gmail dot com>, "
616 "Alessandro Zummo <a.zummo@towertech.it>");
617 MODULE_DESCRIPTION("Xicor/Intersil X1205 RTC driver");
618 MODULE_LICENSE("GPL");
619 MODULE_VERSION(DRV_VERSION);
621 module_init(x1205_init);
622 module_exit(x1205_exit);