2 * Intersil ISL1208 rtc class driver
4 * Copyright 2005,2006 Hebert Valerio Riedel <hvr@gnu.org>
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the
8 * Free Software Foundation; either version 2 of the License, or (at your
9 * option) any later version.
13 #include <linux/module.h>
14 #include <linux/i2c.h>
15 #include <linux/bcd.h>
16 #include <linux/rtc.h>
18 #define DRV_VERSION "0.3"
22 #define ISL1208_REG_SC 0x00
23 #define ISL1208_REG_MN 0x01
24 #define ISL1208_REG_HR 0x02
25 #define ISL1208_REG_HR_MIL (1<<7) /* 24h/12h mode */
26 #define ISL1208_REG_HR_PM (1<<5) /* PM/AM bit in 12h mode */
27 #define ISL1208_REG_DT 0x03
28 #define ISL1208_REG_MO 0x04
29 #define ISL1208_REG_YR 0x05
30 #define ISL1208_REG_DW 0x06
31 #define ISL1208_RTC_SECTION_LEN 7
33 /* control/status section */
34 #define ISL1208_REG_SR 0x07
35 #define ISL1208_REG_SR_ARST (1<<7) /* auto reset */
36 #define ISL1208_REG_SR_XTOSCB (1<<6) /* crystal oscillator */
37 #define ISL1208_REG_SR_WRTC (1<<4) /* write rtc */
38 #define ISL1208_REG_SR_ALM (1<<2) /* alarm */
39 #define ISL1208_REG_SR_BAT (1<<1) /* battery */
40 #define ISL1208_REG_SR_RTCF (1<<0) /* rtc fail */
41 #define ISL1208_REG_INT 0x08
42 #define ISL1208_REG_INT_ALME (1<<6) /* alarm enable */
43 #define ISL1208_REG_INT_IM (1<<7) /* interrupt/alarm mode */
44 #define ISL1208_REG_09 0x09 /* reserved */
45 #define ISL1208_REG_ATR 0x0a
46 #define ISL1208_REG_DTR 0x0b
49 #define ISL1208_REG_SCA 0x0c
50 #define ISL1208_REG_MNA 0x0d
51 #define ISL1208_REG_HRA 0x0e
52 #define ISL1208_REG_DTA 0x0f
53 #define ISL1208_REG_MOA 0x10
54 #define ISL1208_REG_DWA 0x11
55 #define ISL1208_ALARM_SECTION_LEN 6
58 #define ISL1208_REG_USR1 0x12
59 #define ISL1208_REG_USR2 0x13
60 #define ISL1208_USR_SECTION_LEN 2
62 static struct i2c_driver isl1208_driver
;
66 isl1208_i2c_read_regs(struct i2c_client
*client
, u8 reg
, u8 buf
[],
69 u8 reg_addr
[1] = { reg
};
70 struct i2c_msg msgs
[2] = {
73 .len
= sizeof(reg_addr
),
85 BUG_ON(reg
> ISL1208_REG_USR2
);
86 BUG_ON(reg
+ len
> ISL1208_REG_USR2
+ 1);
88 ret
= i2c_transfer(client
->adapter
, msgs
, 2);
96 isl1208_i2c_set_regs(struct i2c_client
*client
, u8 reg
, u8
const buf
[],
99 u8 i2c_buf
[ISL1208_REG_USR2
+ 2];
100 struct i2c_msg msgs
[1] = {
102 .addr
= client
->addr
,
109 BUG_ON(reg
> ISL1208_REG_USR2
);
110 BUG_ON(reg
+ len
> ISL1208_REG_USR2
+ 1);
113 memcpy(&i2c_buf
[1], &buf
[0], len
);
115 ret
= i2c_transfer(client
->adapter
, msgs
, 1);
121 /* simple check to see whether we have a isl1208 */
123 isl1208_i2c_validate_client(struct i2c_client
*client
)
125 u8 regs
[ISL1208_RTC_SECTION_LEN
] = { 0, };
126 u8 zero_mask
[ISL1208_RTC_SECTION_LEN
] = {
127 0x80, 0x80, 0x40, 0xc0, 0xe0, 0x00, 0xf8
132 ret
= isl1208_i2c_read_regs(client
, 0, regs
, ISL1208_RTC_SECTION_LEN
);
136 for (i
= 0; i
< ISL1208_RTC_SECTION_LEN
; ++i
) {
137 if (regs
[i
] & zero_mask
[i
]) /* check if bits are cleared */
145 isl1208_i2c_get_sr(struct i2c_client
*client
)
147 return i2c_smbus_read_byte_data(client
, ISL1208_REG_SR
);
151 isl1208_i2c_get_atr(struct i2c_client
*client
)
153 int atr
= i2c_smbus_read_byte_data(client
, ISL1208_REG_ATR
);
157 /* The 6bit value in the ATR register controls the load
158 * capacitance C_load * in steps of 0.25pF
160 * bit (1<<5) of the ATR register is inverted
162 * C_load(ATR=0x20) = 4.50pF
163 * C_load(ATR=0x00) = 12.50pF
164 * C_load(ATR=0x1f) = 20.25pF
168 atr
&= 0x3f; /* mask out lsb */
169 atr
^= 1 << 5; /* invert 6th bit */
170 atr
+= 2 * 9; /* add offset of 4.5pF; unit[atr] = 0.25pF */
176 isl1208_i2c_get_dtr(struct i2c_client
*client
)
178 int dtr
= i2c_smbus_read_byte_data(client
, ISL1208_REG_DTR
);
182 /* dtr encodes adjustments of {-60,-40,-20,0,20,40,60} ppm */
183 dtr
= ((dtr
& 0x3) * 20) * (dtr
& (1 << 2) ? -1 : 1);
189 isl1208_i2c_get_usr(struct i2c_client
*client
)
191 u8 buf
[ISL1208_USR_SECTION_LEN
] = { 0, };
194 ret
= isl1208_i2c_read_regs(client
, ISL1208_REG_USR1
, buf
,
195 ISL1208_USR_SECTION_LEN
);
199 return (buf
[1] << 8) | buf
[0];
203 isl1208_i2c_set_usr(struct i2c_client
*client
, u16 usr
)
205 u8 buf
[ISL1208_USR_SECTION_LEN
];
208 buf
[1] = (usr
>> 8) & 0xff;
210 return isl1208_i2c_set_regs(client
, ISL1208_REG_USR1
, buf
,
211 ISL1208_USR_SECTION_LEN
);
215 isl1208_rtc_toggle_alarm(struct i2c_client
*client
, int enable
)
217 int icr
= i2c_smbus_read_byte_data(client
, ISL1208_REG_INT
);
220 dev_err(&client
->dev
, "%s: reading INT failed\n", __func__
);
225 icr
|= ISL1208_REG_INT_ALME
| ISL1208_REG_INT_IM
;
227 icr
&= ~(ISL1208_REG_INT_ALME
| ISL1208_REG_INT_IM
);
229 icr
= i2c_smbus_write_byte_data(client
, ISL1208_REG_INT
, icr
);
231 dev_err(&client
->dev
, "%s: writing INT failed\n", __func__
);
239 isl1208_rtc_proc(struct device
*dev
, struct seq_file
*seq
)
241 struct i2c_client
*const client
= to_i2c_client(dev
);
242 int sr
, dtr
, atr
, usr
;
244 sr
= isl1208_i2c_get_sr(client
);
246 dev_err(&client
->dev
, "%s: reading SR failed\n", __func__
);
250 seq_printf(seq
, "status_reg\t:%s%s%s%s%s%s (0x%.2x)\n",
251 (sr
& ISL1208_REG_SR_RTCF
) ? " RTCF" : "",
252 (sr
& ISL1208_REG_SR_BAT
) ? " BAT" : "",
253 (sr
& ISL1208_REG_SR_ALM
) ? " ALM" : "",
254 (sr
& ISL1208_REG_SR_WRTC
) ? " WRTC" : "",
255 (sr
& ISL1208_REG_SR_XTOSCB
) ? " XTOSCB" : "",
256 (sr
& ISL1208_REG_SR_ARST
) ? " ARST" : "", sr
);
258 seq_printf(seq
, "batt_status\t: %s\n",
259 (sr
& ISL1208_REG_SR_RTCF
) ? "bad" : "okay");
261 dtr
= isl1208_i2c_get_dtr(client
);
263 seq_printf(seq
, "digital_trim\t: %d ppm\n", dtr
);
265 atr
= isl1208_i2c_get_atr(client
);
267 seq_printf(seq
, "analog_trim\t: %d.%.2d pF\n",
268 atr
>> 2, (atr
& 0x3) * 25);
270 usr
= isl1208_i2c_get_usr(client
);
272 seq_printf(seq
, "user_data\t: 0x%.4x\n", usr
);
278 isl1208_i2c_read_time(struct i2c_client
*client
, struct rtc_time
*tm
)
281 u8 regs
[ISL1208_RTC_SECTION_LEN
] = { 0, };
283 sr
= isl1208_i2c_get_sr(client
);
285 dev_err(&client
->dev
, "%s: reading SR failed\n", __func__
);
289 sr
= isl1208_i2c_read_regs(client
, 0, regs
, ISL1208_RTC_SECTION_LEN
);
291 dev_err(&client
->dev
, "%s: reading RTC section failed\n",
296 tm
->tm_sec
= bcd2bin(regs
[ISL1208_REG_SC
]);
297 tm
->tm_min
= bcd2bin(regs
[ISL1208_REG_MN
]);
299 /* HR field has a more complex interpretation */
301 const u8 _hr
= regs
[ISL1208_REG_HR
];
302 if (_hr
& ISL1208_REG_HR_MIL
) /* 24h format */
303 tm
->tm_hour
= bcd2bin(_hr
& 0x3f);
306 tm
->tm_hour
= bcd2bin(_hr
& 0x1f);
307 if (_hr
& ISL1208_REG_HR_PM
) /* PM flag set */
312 tm
->tm_mday
= bcd2bin(regs
[ISL1208_REG_DT
]);
313 tm
->tm_mon
= bcd2bin(regs
[ISL1208_REG_MO
]) - 1; /* rtc starts at 1 */
314 tm
->tm_year
= bcd2bin(regs
[ISL1208_REG_YR
]) + 100;
315 tm
->tm_wday
= bcd2bin(regs
[ISL1208_REG_DW
]);
321 isl1208_i2c_read_alarm(struct i2c_client
*client
, struct rtc_wkalrm
*alarm
)
323 struct rtc_time
*const tm
= &alarm
->time
;
324 u8 regs
[ISL1208_ALARM_SECTION_LEN
] = { 0, };
325 int icr
, yr
, sr
= isl1208_i2c_get_sr(client
);
328 dev_err(&client
->dev
, "%s: reading SR failed\n", __func__
);
332 sr
= isl1208_i2c_read_regs(client
, ISL1208_REG_SCA
, regs
,
333 ISL1208_ALARM_SECTION_LEN
);
335 dev_err(&client
->dev
, "%s: reading alarm section failed\n",
340 /* MSB of each alarm register is an enable bit */
341 tm
->tm_sec
= bcd2bin(regs
[ISL1208_REG_SCA
- ISL1208_REG_SCA
] & 0x7f);
342 tm
->tm_min
= bcd2bin(regs
[ISL1208_REG_MNA
- ISL1208_REG_SCA
] & 0x7f);
343 tm
->tm_hour
= bcd2bin(regs
[ISL1208_REG_HRA
- ISL1208_REG_SCA
] & 0x3f);
344 tm
->tm_mday
= bcd2bin(regs
[ISL1208_REG_DTA
- ISL1208_REG_SCA
] & 0x3f);
346 bcd2bin(regs
[ISL1208_REG_MOA
- ISL1208_REG_SCA
] & 0x1f) - 1;
347 tm
->tm_wday
= bcd2bin(regs
[ISL1208_REG_DWA
- ISL1208_REG_SCA
] & 0x03);
349 /* The alarm doesn't store the year so get it from the rtc section */
350 yr
= i2c_smbus_read_byte_data(client
, ISL1208_REG_YR
);
352 dev_err(&client
->dev
, "%s: reading RTC YR failed\n", __func__
);
355 tm
->tm_year
= bcd2bin(yr
) + 100;
357 icr
= i2c_smbus_read_byte_data(client
, ISL1208_REG_INT
);
359 dev_err(&client
->dev
, "%s: reading INT failed\n", __func__
);
362 alarm
->enabled
= !!(icr
& ISL1208_REG_INT_ALME
);
368 isl1208_i2c_set_alarm(struct i2c_client
*client
, struct rtc_wkalrm
*alarm
)
370 struct rtc_time
*alarm_tm
= &alarm
->time
;
371 u8 regs
[ISL1208_ALARM_SECTION_LEN
] = { 0, };
372 const int offs
= ISL1208_REG_SCA
;
373 unsigned long rtc_secs
, alarm_secs
;
374 struct rtc_time rtc_tm
;
377 err
= isl1208_i2c_read_time(client
, &rtc_tm
);
380 err
= rtc_tm_to_time(&rtc_tm
, &rtc_secs
);
383 err
= rtc_tm_to_time(alarm_tm
, &alarm_secs
);
387 /* If the alarm time is before the current time disable the alarm */
388 if (!alarm
->enabled
|| alarm_secs
<= rtc_secs
)
393 /* Program the alarm and enable it for each setting */
394 regs
[ISL1208_REG_SCA
- offs
] = bin2bcd(alarm_tm
->tm_sec
) | enable
;
395 regs
[ISL1208_REG_MNA
- offs
] = bin2bcd(alarm_tm
->tm_min
) | enable
;
396 regs
[ISL1208_REG_HRA
- offs
] = bin2bcd(alarm_tm
->tm_hour
) |
397 ISL1208_REG_HR_MIL
| enable
;
399 regs
[ISL1208_REG_DTA
- offs
] = bin2bcd(alarm_tm
->tm_mday
) | enable
;
400 regs
[ISL1208_REG_MOA
- offs
] = bin2bcd(alarm_tm
->tm_mon
+ 1) | enable
;
401 regs
[ISL1208_REG_DWA
- offs
] = bin2bcd(alarm_tm
->tm_wday
& 7) | enable
;
403 /* write ALARM registers */
404 err
= isl1208_i2c_set_regs(client
, offs
, regs
,
405 ISL1208_ALARM_SECTION_LEN
);
407 dev_err(&client
->dev
, "%s: writing ALARM section failed\n",
412 err
= isl1208_rtc_toggle_alarm(client
, enable
);
420 isl1208_rtc_read_time(struct device
*dev
, struct rtc_time
*tm
)
422 return isl1208_i2c_read_time(to_i2c_client(dev
), tm
);
426 isl1208_i2c_set_time(struct i2c_client
*client
, struct rtc_time
const *tm
)
429 u8 regs
[ISL1208_RTC_SECTION_LEN
] = { 0, };
431 /* The clock has an 8 bit wide bcd-coded register (they never learn)
432 * for the year. tm_year is an offset from 1900 and we are interested
433 * in the 2000-2099 range, so any value less than 100 is invalid.
435 if (tm
->tm_year
< 100)
438 regs
[ISL1208_REG_SC
] = bin2bcd(tm
->tm_sec
);
439 regs
[ISL1208_REG_MN
] = bin2bcd(tm
->tm_min
);
440 regs
[ISL1208_REG_HR
] = bin2bcd(tm
->tm_hour
) | ISL1208_REG_HR_MIL
;
442 regs
[ISL1208_REG_DT
] = bin2bcd(tm
->tm_mday
);
443 regs
[ISL1208_REG_MO
] = bin2bcd(tm
->tm_mon
+ 1);
444 regs
[ISL1208_REG_YR
] = bin2bcd(tm
->tm_year
- 100);
446 regs
[ISL1208_REG_DW
] = bin2bcd(tm
->tm_wday
& 7);
448 sr
= isl1208_i2c_get_sr(client
);
450 dev_err(&client
->dev
, "%s: reading SR failed\n", __func__
);
455 sr
= i2c_smbus_write_byte_data(client
, ISL1208_REG_SR
,
456 sr
| ISL1208_REG_SR_WRTC
);
458 dev_err(&client
->dev
, "%s: writing SR failed\n", __func__
);
462 /* write RTC registers */
463 sr
= isl1208_i2c_set_regs(client
, 0, regs
, ISL1208_RTC_SECTION_LEN
);
465 dev_err(&client
->dev
, "%s: writing RTC section failed\n",
470 /* clear WRTC again */
471 sr
= i2c_smbus_write_byte_data(client
, ISL1208_REG_SR
,
472 sr
& ~ISL1208_REG_SR_WRTC
);
474 dev_err(&client
->dev
, "%s: writing SR failed\n", __func__
);
483 isl1208_rtc_set_time(struct device
*dev
, struct rtc_time
*tm
)
485 return isl1208_i2c_set_time(to_i2c_client(dev
), tm
);
489 isl1208_rtc_read_alarm(struct device
*dev
, struct rtc_wkalrm
*alarm
)
491 return isl1208_i2c_read_alarm(to_i2c_client(dev
), alarm
);
495 isl1208_rtc_set_alarm(struct device
*dev
, struct rtc_wkalrm
*alarm
)
497 return isl1208_i2c_set_alarm(to_i2c_client(dev
), alarm
);
501 isl1208_rtc_interrupt(int irq
, void *data
)
503 unsigned long timeout
= jiffies
+ msecs_to_jiffies(1000);
504 struct i2c_client
*client
= data
;
505 struct rtc_device
*rtc
= i2c_get_clientdata(client
);
506 int handled
= 0, sr
, err
;
509 * I2C reads get NAK'ed if we read straight away after an interrupt?
510 * Using a mdelay/msleep didn't seem to help either, so we work around
511 * this by continually trying to read the register for a short time.
514 sr
= isl1208_i2c_get_sr(client
);
518 if (time_after(jiffies
, timeout
)) {
519 dev_err(&client
->dev
, "%s: reading SR failed\n",
525 if (sr
& ISL1208_REG_SR_ALM
) {
526 dev_dbg(&client
->dev
, "alarm!\n");
528 rtc_update_irq(rtc
, 1, RTC_IRQF
| RTC_AF
);
530 /* Clear the alarm */
531 sr
&= ~ISL1208_REG_SR_ALM
;
532 sr
= i2c_smbus_write_byte_data(client
, ISL1208_REG_SR
, sr
);
534 dev_err(&client
->dev
, "%s: writing SR failed\n",
539 /* Disable the alarm */
540 err
= isl1208_rtc_toggle_alarm(client
, 0);
545 return handled
? IRQ_HANDLED
: IRQ_NONE
;
548 static const struct rtc_class_ops isl1208_rtc_ops
= {
549 .proc
= isl1208_rtc_proc
,
550 .read_time
= isl1208_rtc_read_time
,
551 .set_time
= isl1208_rtc_set_time
,
552 .read_alarm
= isl1208_rtc_read_alarm
,
553 .set_alarm
= isl1208_rtc_set_alarm
,
556 /* sysfs interface */
559 isl1208_sysfs_show_atrim(struct device
*dev
,
560 struct device_attribute
*attr
, char *buf
)
562 int atr
= isl1208_i2c_get_atr(to_i2c_client(dev
));
566 return sprintf(buf
, "%d.%.2d pF\n", atr
>> 2, (atr
& 0x3) * 25);
569 static DEVICE_ATTR(atrim
, S_IRUGO
, isl1208_sysfs_show_atrim
, NULL
);
572 isl1208_sysfs_show_dtrim(struct device
*dev
,
573 struct device_attribute
*attr
, char *buf
)
575 int dtr
= isl1208_i2c_get_dtr(to_i2c_client(dev
));
579 return sprintf(buf
, "%d ppm\n", dtr
);
582 static DEVICE_ATTR(dtrim
, S_IRUGO
, isl1208_sysfs_show_dtrim
, NULL
);
585 isl1208_sysfs_show_usr(struct device
*dev
,
586 struct device_attribute
*attr
, char *buf
)
588 int usr
= isl1208_i2c_get_usr(to_i2c_client(dev
));
592 return sprintf(buf
, "0x%.4x\n", usr
);
596 isl1208_sysfs_store_usr(struct device
*dev
,
597 struct device_attribute
*attr
,
598 const char *buf
, size_t count
)
602 if (buf
[0] == '0' && (buf
[1] == 'x' || buf
[1] == 'X')) {
603 if (sscanf(buf
, "%x", &usr
) != 1)
606 if (sscanf(buf
, "%d", &usr
) != 1)
610 if (usr
< 0 || usr
> 0xffff)
613 return isl1208_i2c_set_usr(to_i2c_client(dev
), usr
) ? -EIO
: count
;
616 static DEVICE_ATTR(usr
, S_IRUGO
| S_IWUSR
, isl1208_sysfs_show_usr
,
617 isl1208_sysfs_store_usr
);
619 static struct attribute
*isl1208_rtc_attrs
[] = {
620 &dev_attr_atrim
.attr
,
621 &dev_attr_dtrim
.attr
,
626 static const struct attribute_group isl1208_rtc_sysfs_files
= {
627 .attrs
= isl1208_rtc_attrs
,
631 isl1208_probe(struct i2c_client
*client
, const struct i2c_device_id
*id
)
634 struct rtc_device
*rtc
;
636 if (!i2c_check_functionality(client
->adapter
, I2C_FUNC_I2C
))
639 if (isl1208_i2c_validate_client(client
) < 0)
642 dev_info(&client
->dev
,
643 "chip found, driver version " DRV_VERSION
"\n");
645 if (client
->irq
> 0) {
646 rc
= devm_request_threaded_irq(&client
->dev
, client
->irq
, NULL
,
647 isl1208_rtc_interrupt
,
649 isl1208_driver
.driver
.name
,
652 device_init_wakeup(&client
->dev
, 1);
653 enable_irq_wake(client
->irq
);
655 dev_err(&client
->dev
,
656 "Unable to request irq %d, no alarm support\n",
662 rtc
= devm_rtc_device_register(&client
->dev
, isl1208_driver
.driver
.name
,
668 i2c_set_clientdata(client
, rtc
);
670 rc
= isl1208_i2c_get_sr(client
);
672 dev_err(&client
->dev
, "reading status failed\n");
676 if (rc
& ISL1208_REG_SR_RTCF
)
677 dev_warn(&client
->dev
, "rtc power failure detected, "
678 "please set clock.\n");
680 rc
= sysfs_create_group(&client
->dev
.kobj
, &isl1208_rtc_sysfs_files
);
688 isl1208_remove(struct i2c_client
*client
)
690 sysfs_remove_group(&client
->dev
.kobj
, &isl1208_rtc_sysfs_files
);
695 static const struct i2c_device_id isl1208_id
[] = {
700 MODULE_DEVICE_TABLE(i2c
, isl1208_id
);
702 static struct i2c_driver isl1208_driver
= {
704 .name
= "rtc-isl1208",
706 .probe
= isl1208_probe
,
707 .remove
= isl1208_remove
,
708 .id_table
= isl1208_id
,
711 module_i2c_driver(isl1208_driver
);
713 MODULE_AUTHOR("Herbert Valerio Riedel <hvr@gnu.org>");
714 MODULE_DESCRIPTION("Intersil ISL1208 RTC driver");
715 MODULE_LICENSE("GPL");
716 MODULE_VERSION(DRV_VERSION
);