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 int sr
= i2c_smbus_read_byte_data(client
, ISL1208_REG_SR
);
155 isl1208_i2c_get_atr(struct i2c_client
*client
)
157 int atr
= i2c_smbus_read_byte_data(client
, ISL1208_REG_ATR
);
161 /* The 6bit value in the ATR register controls the load
162 * capacitance C_load * in steps of 0.25pF
164 * bit (1<<5) of the ATR register is inverted
166 * C_load(ATR=0x20) = 4.50pF
167 * C_load(ATR=0x00) = 12.50pF
168 * C_load(ATR=0x1f) = 20.25pF
172 atr
&= 0x3f; /* mask out lsb */
173 atr
^= 1 << 5; /* invert 6th bit */
174 atr
+= 2 * 9; /* add offset of 4.5pF; unit[atr] = 0.25pF */
180 isl1208_i2c_get_dtr(struct i2c_client
*client
)
182 int dtr
= i2c_smbus_read_byte_data(client
, ISL1208_REG_DTR
);
186 /* dtr encodes adjustments of {-60,-40,-20,0,20,40,60} ppm */
187 dtr
= ((dtr
& 0x3) * 20) * (dtr
& (1 << 2) ? -1 : 1);
193 isl1208_i2c_get_usr(struct i2c_client
*client
)
195 u8 buf
[ISL1208_USR_SECTION_LEN
] = { 0, };
198 ret
= isl1208_i2c_read_regs(client
, ISL1208_REG_USR1
, buf
,
199 ISL1208_USR_SECTION_LEN
);
203 return (buf
[1] << 8) | buf
[0];
207 isl1208_i2c_set_usr(struct i2c_client
*client
, u16 usr
)
209 u8 buf
[ISL1208_USR_SECTION_LEN
];
212 buf
[1] = (usr
>> 8) & 0xff;
214 return isl1208_i2c_set_regs(client
, ISL1208_REG_USR1
, buf
,
215 ISL1208_USR_SECTION_LEN
);
219 isl1208_rtc_toggle_alarm(struct i2c_client
*client
, int enable
)
221 int icr
= i2c_smbus_read_byte_data(client
, ISL1208_REG_INT
);
224 dev_err(&client
->dev
, "%s: reading INT failed\n", __func__
);
229 icr
|= ISL1208_REG_INT_ALME
| ISL1208_REG_INT_IM
;
231 icr
&= ~(ISL1208_REG_INT_ALME
| ISL1208_REG_INT_IM
);
233 icr
= i2c_smbus_write_byte_data(client
, ISL1208_REG_INT
, icr
);
235 dev_err(&client
->dev
, "%s: writing INT failed\n", __func__
);
243 isl1208_rtc_proc(struct device
*dev
, struct seq_file
*seq
)
245 struct i2c_client
*const client
= to_i2c_client(dev
);
246 int sr
, dtr
, atr
, usr
;
248 sr
= isl1208_i2c_get_sr(client
);
250 dev_err(&client
->dev
, "%s: reading SR failed\n", __func__
);
254 seq_printf(seq
, "status_reg\t:%s%s%s%s%s%s (0x%.2x)\n",
255 (sr
& ISL1208_REG_SR_RTCF
) ? " RTCF" : "",
256 (sr
& ISL1208_REG_SR_BAT
) ? " BAT" : "",
257 (sr
& ISL1208_REG_SR_ALM
) ? " ALM" : "",
258 (sr
& ISL1208_REG_SR_WRTC
) ? " WRTC" : "",
259 (sr
& ISL1208_REG_SR_XTOSCB
) ? " XTOSCB" : "",
260 (sr
& ISL1208_REG_SR_ARST
) ? " ARST" : "", sr
);
262 seq_printf(seq
, "batt_status\t: %s\n",
263 (sr
& ISL1208_REG_SR_RTCF
) ? "bad" : "okay");
265 dtr
= isl1208_i2c_get_dtr(client
);
267 seq_printf(seq
, "digital_trim\t: %d ppm\n", dtr
);
269 atr
= isl1208_i2c_get_atr(client
);
271 seq_printf(seq
, "analog_trim\t: %d.%.2d pF\n",
272 atr
>> 2, (atr
& 0x3) * 25);
274 usr
= isl1208_i2c_get_usr(client
);
276 seq_printf(seq
, "user_data\t: 0x%.4x\n", usr
);
282 isl1208_i2c_read_time(struct i2c_client
*client
, struct rtc_time
*tm
)
285 u8 regs
[ISL1208_RTC_SECTION_LEN
] = { 0, };
287 sr
= isl1208_i2c_get_sr(client
);
289 dev_err(&client
->dev
, "%s: reading SR failed\n", __func__
);
293 sr
= isl1208_i2c_read_regs(client
, 0, regs
, ISL1208_RTC_SECTION_LEN
);
295 dev_err(&client
->dev
, "%s: reading RTC section failed\n",
300 tm
->tm_sec
= bcd2bin(regs
[ISL1208_REG_SC
]);
301 tm
->tm_min
= bcd2bin(regs
[ISL1208_REG_MN
]);
303 /* HR field has a more complex interpretation */
305 const u8 _hr
= regs
[ISL1208_REG_HR
];
306 if (_hr
& ISL1208_REG_HR_MIL
) /* 24h format */
307 tm
->tm_hour
= bcd2bin(_hr
& 0x3f);
310 tm
->tm_hour
= bcd2bin(_hr
& 0x1f);
311 if (_hr
& ISL1208_REG_HR_PM
) /* PM flag set */
316 tm
->tm_mday
= bcd2bin(regs
[ISL1208_REG_DT
]);
317 tm
->tm_mon
= bcd2bin(regs
[ISL1208_REG_MO
]) - 1; /* rtc starts at 1 */
318 tm
->tm_year
= bcd2bin(regs
[ISL1208_REG_YR
]) + 100;
319 tm
->tm_wday
= bcd2bin(regs
[ISL1208_REG_DW
]);
325 isl1208_i2c_read_alarm(struct i2c_client
*client
, struct rtc_wkalrm
*alarm
)
327 struct rtc_time
*const tm
= &alarm
->time
;
328 u8 regs
[ISL1208_ALARM_SECTION_LEN
] = { 0, };
329 int icr
, yr
, sr
= isl1208_i2c_get_sr(client
);
332 dev_err(&client
->dev
, "%s: reading SR failed\n", __func__
);
336 sr
= isl1208_i2c_read_regs(client
, ISL1208_REG_SCA
, regs
,
337 ISL1208_ALARM_SECTION_LEN
);
339 dev_err(&client
->dev
, "%s: reading alarm section failed\n",
344 /* MSB of each alarm register is an enable bit */
345 tm
->tm_sec
= bcd2bin(regs
[ISL1208_REG_SCA
- ISL1208_REG_SCA
] & 0x7f);
346 tm
->tm_min
= bcd2bin(regs
[ISL1208_REG_MNA
- ISL1208_REG_SCA
] & 0x7f);
347 tm
->tm_hour
= bcd2bin(regs
[ISL1208_REG_HRA
- ISL1208_REG_SCA
] & 0x3f);
348 tm
->tm_mday
= bcd2bin(regs
[ISL1208_REG_DTA
- ISL1208_REG_SCA
] & 0x3f);
350 bcd2bin(regs
[ISL1208_REG_MOA
- ISL1208_REG_SCA
] & 0x1f) - 1;
351 tm
->tm_wday
= bcd2bin(regs
[ISL1208_REG_DWA
- ISL1208_REG_SCA
] & 0x03);
353 /* The alarm doesn't store the year so get it from the rtc section */
354 yr
= i2c_smbus_read_byte_data(client
, ISL1208_REG_YR
);
356 dev_err(&client
->dev
, "%s: reading RTC YR failed\n", __func__
);
359 tm
->tm_year
= bcd2bin(yr
) + 100;
361 icr
= i2c_smbus_read_byte_data(client
, ISL1208_REG_INT
);
363 dev_err(&client
->dev
, "%s: reading INT failed\n", __func__
);
366 alarm
->enabled
= !!(icr
& ISL1208_REG_INT_ALME
);
372 isl1208_i2c_set_alarm(struct i2c_client
*client
, struct rtc_wkalrm
*alarm
)
374 struct rtc_time
*alarm_tm
= &alarm
->time
;
375 u8 regs
[ISL1208_ALARM_SECTION_LEN
] = { 0, };
376 const int offs
= ISL1208_REG_SCA
;
377 unsigned long rtc_secs
, alarm_secs
;
378 struct rtc_time rtc_tm
;
381 err
= isl1208_i2c_read_time(client
, &rtc_tm
);
384 err
= rtc_tm_to_time(&rtc_tm
, &rtc_secs
);
387 err
= rtc_tm_to_time(alarm_tm
, &alarm_secs
);
391 /* If the alarm time is before the current time disable the alarm */
392 if (!alarm
->enabled
|| alarm_secs
<= rtc_secs
)
397 /* Program the alarm and enable it for each setting */
398 regs
[ISL1208_REG_SCA
- offs
] = bin2bcd(alarm_tm
->tm_sec
) | enable
;
399 regs
[ISL1208_REG_MNA
- offs
] = bin2bcd(alarm_tm
->tm_min
) | enable
;
400 regs
[ISL1208_REG_HRA
- offs
] = bin2bcd(alarm_tm
->tm_hour
) |
401 ISL1208_REG_HR_MIL
| enable
;
403 regs
[ISL1208_REG_DTA
- offs
] = bin2bcd(alarm_tm
->tm_mday
) | enable
;
404 regs
[ISL1208_REG_MOA
- offs
] = bin2bcd(alarm_tm
->tm_mon
+ 1) | enable
;
405 regs
[ISL1208_REG_DWA
- offs
] = bin2bcd(alarm_tm
->tm_wday
& 7) | enable
;
407 /* write ALARM registers */
408 err
= isl1208_i2c_set_regs(client
, offs
, regs
,
409 ISL1208_ALARM_SECTION_LEN
);
411 dev_err(&client
->dev
, "%s: writing ALARM section failed\n",
416 err
= isl1208_rtc_toggle_alarm(client
, enable
);
424 isl1208_rtc_read_time(struct device
*dev
, struct rtc_time
*tm
)
426 return isl1208_i2c_read_time(to_i2c_client(dev
), tm
);
430 isl1208_i2c_set_time(struct i2c_client
*client
, struct rtc_time
const *tm
)
433 u8 regs
[ISL1208_RTC_SECTION_LEN
] = { 0, };
435 /* The clock has an 8 bit wide bcd-coded register (they never learn)
436 * for the year. tm_year is an offset from 1900 and we are interested
437 * in the 2000-2099 range, so any value less than 100 is invalid.
439 if (tm
->tm_year
< 100)
442 regs
[ISL1208_REG_SC
] = bin2bcd(tm
->tm_sec
);
443 regs
[ISL1208_REG_MN
] = bin2bcd(tm
->tm_min
);
444 regs
[ISL1208_REG_HR
] = bin2bcd(tm
->tm_hour
) | ISL1208_REG_HR_MIL
;
446 regs
[ISL1208_REG_DT
] = bin2bcd(tm
->tm_mday
);
447 regs
[ISL1208_REG_MO
] = bin2bcd(tm
->tm_mon
+ 1);
448 regs
[ISL1208_REG_YR
] = bin2bcd(tm
->tm_year
- 100);
450 regs
[ISL1208_REG_DW
] = bin2bcd(tm
->tm_wday
& 7);
452 sr
= isl1208_i2c_get_sr(client
);
454 dev_err(&client
->dev
, "%s: reading SR failed\n", __func__
);
459 sr
= i2c_smbus_write_byte_data(client
, ISL1208_REG_SR
,
460 sr
| ISL1208_REG_SR_WRTC
);
462 dev_err(&client
->dev
, "%s: writing SR failed\n", __func__
);
466 /* write RTC registers */
467 sr
= isl1208_i2c_set_regs(client
, 0, regs
, ISL1208_RTC_SECTION_LEN
);
469 dev_err(&client
->dev
, "%s: writing RTC section failed\n",
474 /* clear WRTC again */
475 sr
= i2c_smbus_write_byte_data(client
, ISL1208_REG_SR
,
476 sr
& ~ISL1208_REG_SR_WRTC
);
478 dev_err(&client
->dev
, "%s: writing SR failed\n", __func__
);
487 isl1208_rtc_set_time(struct device
*dev
, struct rtc_time
*tm
)
489 return isl1208_i2c_set_time(to_i2c_client(dev
), tm
);
493 isl1208_rtc_read_alarm(struct device
*dev
, struct rtc_wkalrm
*alarm
)
495 return isl1208_i2c_read_alarm(to_i2c_client(dev
), alarm
);
499 isl1208_rtc_set_alarm(struct device
*dev
, struct rtc_wkalrm
*alarm
)
501 return isl1208_i2c_set_alarm(to_i2c_client(dev
), alarm
);
505 isl1208_rtc_interrupt(int irq
, void *data
)
507 unsigned long timeout
= jiffies
+ msecs_to_jiffies(1000);
508 struct i2c_client
*client
= data
;
509 int handled
= 0, sr
, err
;
512 * I2C reads get NAK'ed if we read straight away after an interrupt?
513 * Using a mdelay/msleep didn't seem to help either, so we work around
514 * this by continually trying to read the register for a short time.
517 sr
= isl1208_i2c_get_sr(client
);
521 if (time_after(jiffies
, timeout
)) {
522 dev_err(&client
->dev
, "%s: reading SR failed\n",
528 if (sr
& ISL1208_REG_SR_ALM
) {
529 dev_dbg(&client
->dev
, "alarm!\n");
531 /* Clear the alarm */
532 sr
&= ~ISL1208_REG_SR_ALM
;
533 sr
= i2c_smbus_write_byte_data(client
, ISL1208_REG_SR
, sr
);
535 dev_err(&client
->dev
, "%s: writing SR failed\n",
540 /* Disable the alarm */
541 err
= isl1208_rtc_toggle_alarm(client
, 0);
546 return handled
? IRQ_HANDLED
: IRQ_NONE
;
549 static const struct rtc_class_ops isl1208_rtc_ops
= {
550 .proc
= isl1208_rtc_proc
,
551 .read_time
= isl1208_rtc_read_time
,
552 .set_time
= isl1208_rtc_set_time
,
553 .read_alarm
= isl1208_rtc_read_alarm
,
554 .set_alarm
= isl1208_rtc_set_alarm
,
557 /* sysfs interface */
560 isl1208_sysfs_show_atrim(struct device
*dev
,
561 struct device_attribute
*attr
, char *buf
)
563 int atr
= isl1208_i2c_get_atr(to_i2c_client(dev
));
567 return sprintf(buf
, "%d.%.2d pF\n", atr
>> 2, (atr
& 0x3) * 25);
570 static DEVICE_ATTR(atrim
, S_IRUGO
, isl1208_sysfs_show_atrim
, NULL
);
573 isl1208_sysfs_show_dtrim(struct device
*dev
,
574 struct device_attribute
*attr
, char *buf
)
576 int dtr
= isl1208_i2c_get_dtr(to_i2c_client(dev
));
580 return sprintf(buf
, "%d ppm\n", dtr
);
583 static DEVICE_ATTR(dtrim
, S_IRUGO
, isl1208_sysfs_show_dtrim
, NULL
);
586 isl1208_sysfs_show_usr(struct device
*dev
,
587 struct device_attribute
*attr
, char *buf
)
589 int usr
= isl1208_i2c_get_usr(to_i2c_client(dev
));
593 return sprintf(buf
, "0x%.4x\n", usr
);
597 isl1208_sysfs_store_usr(struct device
*dev
,
598 struct device_attribute
*attr
,
599 const char *buf
, size_t count
)
603 if (buf
[0] == '0' && (buf
[1] == 'x' || buf
[1] == 'X')) {
604 if (sscanf(buf
, "%x", &usr
) != 1)
607 if (sscanf(buf
, "%d", &usr
) != 1)
611 if (usr
< 0 || usr
> 0xffff)
614 return isl1208_i2c_set_usr(to_i2c_client(dev
), usr
) ? -EIO
: count
;
617 static DEVICE_ATTR(usr
, S_IRUGO
| S_IWUSR
, isl1208_sysfs_show_usr
,
618 isl1208_sysfs_store_usr
);
620 static struct attribute
*isl1208_rtc_attrs
[] = {
621 &dev_attr_atrim
.attr
,
622 &dev_attr_dtrim
.attr
,
627 static const struct attribute_group isl1208_rtc_sysfs_files
= {
628 .attrs
= isl1208_rtc_attrs
,
632 isl1208_probe(struct i2c_client
*client
, const struct i2c_device_id
*id
)
635 struct rtc_device
*rtc
;
637 if (!i2c_check_functionality(client
->adapter
, I2C_FUNC_I2C
))
640 if (isl1208_i2c_validate_client(client
) < 0)
643 dev_info(&client
->dev
,
644 "chip found, driver version " DRV_VERSION
"\n");
646 if (client
->irq
> 0) {
647 rc
= request_threaded_irq(client
->irq
, NULL
,
648 isl1208_rtc_interrupt
,
650 isl1208_driver
.driver
.name
, client
);
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
= rtc_device_register(isl1208_driver
.driver
.name
,
663 &client
->dev
, &isl1208_rtc_ops
,
670 i2c_set_clientdata(client
, rtc
);
672 rc
= isl1208_i2c_get_sr(client
);
674 dev_err(&client
->dev
, "reading status failed\n");
675 goto exit_unregister
;
678 if (rc
& ISL1208_REG_SR_RTCF
)
679 dev_warn(&client
->dev
, "rtc power failure detected, "
680 "please set clock.\n");
682 rc
= sysfs_create_group(&client
->dev
.kobj
, &isl1208_rtc_sysfs_files
);
684 goto exit_unregister
;
689 rtc_device_unregister(rtc
);
692 free_irq(client
->irq
, client
);
698 isl1208_remove(struct i2c_client
*client
)
700 struct rtc_device
*rtc
= i2c_get_clientdata(client
);
702 sysfs_remove_group(&client
->dev
.kobj
, &isl1208_rtc_sysfs_files
);
703 rtc_device_unregister(rtc
);
705 free_irq(client
->irq
, client
);
710 static const struct i2c_device_id isl1208_id
[] = {
715 MODULE_DEVICE_TABLE(i2c
, isl1208_id
);
717 static struct i2c_driver isl1208_driver
= {
719 .name
= "rtc-isl1208",
721 .probe
= isl1208_probe
,
722 .remove
= isl1208_remove
,
723 .id_table
= isl1208_id
,
726 module_i2c_driver(isl1208_driver
);
728 MODULE_AUTHOR("Herbert Valerio Riedel <hvr@gnu.org>");
729 MODULE_DESCRIPTION("Intersil ISL1208 RTC driver");
730 MODULE_LICENSE("GPL");
731 MODULE_VERSION(DRV_VERSION
);