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>
20 #define ISL1208_REG_SC 0x00
21 #define ISL1208_REG_MN 0x01
22 #define ISL1208_REG_HR 0x02
23 #define ISL1208_REG_HR_MIL (1<<7) /* 24h/12h mode */
24 #define ISL1208_REG_HR_PM (1<<5) /* PM/AM bit in 12h mode */
25 #define ISL1208_REG_DT 0x03
26 #define ISL1208_REG_MO 0x04
27 #define ISL1208_REG_YR 0x05
28 #define ISL1208_REG_DW 0x06
29 #define ISL1208_RTC_SECTION_LEN 7
31 /* control/status section */
32 #define ISL1208_REG_SR 0x07
33 #define ISL1208_REG_SR_ARST (1<<7) /* auto reset */
34 #define ISL1208_REG_SR_XTOSCB (1<<6) /* crystal oscillator */
35 #define ISL1208_REG_SR_WRTC (1<<4) /* write rtc */
36 #define ISL1208_REG_SR_ALM (1<<2) /* alarm */
37 #define ISL1208_REG_SR_BAT (1<<1) /* battery */
38 #define ISL1208_REG_SR_RTCF (1<<0) /* rtc fail */
39 #define ISL1208_REG_INT 0x08
40 #define ISL1208_REG_INT_ALME (1<<6) /* alarm enable */
41 #define ISL1208_REG_INT_IM (1<<7) /* interrupt/alarm mode */
42 #define ISL1208_REG_09 0x09 /* reserved */
43 #define ISL1208_REG_ATR 0x0a
44 #define ISL1208_REG_DTR 0x0b
47 #define ISL1208_REG_SCA 0x0c
48 #define ISL1208_REG_MNA 0x0d
49 #define ISL1208_REG_HRA 0x0e
50 #define ISL1208_REG_DTA 0x0f
51 #define ISL1208_REG_MOA 0x10
52 #define ISL1208_REG_DWA 0x11
53 #define ISL1208_ALARM_SECTION_LEN 6
56 #define ISL1208_REG_USR1 0x12
57 #define ISL1208_REG_USR2 0x13
58 #define ISL1208_USR_SECTION_LEN 2
60 static struct i2c_driver isl1208_driver
;
64 isl1208_i2c_read_regs(struct i2c_client
*client
, u8 reg
, u8 buf
[],
67 u8 reg_addr
[1] = { reg
};
68 struct i2c_msg msgs
[2] = {
71 .len
= sizeof(reg_addr
),
83 BUG_ON(reg
> ISL1208_REG_USR2
);
84 BUG_ON(reg
+ len
> ISL1208_REG_USR2
+ 1);
86 ret
= i2c_transfer(client
->adapter
, msgs
, 2);
94 isl1208_i2c_set_regs(struct i2c_client
*client
, u8 reg
, u8
const buf
[],
97 u8 i2c_buf
[ISL1208_REG_USR2
+ 2];
98 struct i2c_msg msgs
[1] = {
100 .addr
= client
->addr
,
107 BUG_ON(reg
> ISL1208_REG_USR2
);
108 BUG_ON(reg
+ len
> ISL1208_REG_USR2
+ 1);
111 memcpy(&i2c_buf
[1], &buf
[0], len
);
113 ret
= i2c_transfer(client
->adapter
, msgs
, 1);
119 /* simple check to see whether we have a isl1208 */
121 isl1208_i2c_validate_client(struct i2c_client
*client
)
123 u8 regs
[ISL1208_RTC_SECTION_LEN
] = { 0, };
124 u8 zero_mask
[ISL1208_RTC_SECTION_LEN
] = {
125 0x80, 0x80, 0x40, 0xc0, 0xe0, 0x00, 0xf8
130 ret
= isl1208_i2c_read_regs(client
, 0, regs
, ISL1208_RTC_SECTION_LEN
);
134 for (i
= 0; i
< ISL1208_RTC_SECTION_LEN
; ++i
) {
135 if (regs
[i
] & zero_mask
[i
]) /* check if bits are cleared */
143 isl1208_i2c_get_sr(struct i2c_client
*client
)
145 return i2c_smbus_read_byte_data(client
, ISL1208_REG_SR
);
149 isl1208_i2c_get_atr(struct i2c_client
*client
)
151 int atr
= i2c_smbus_read_byte_data(client
, ISL1208_REG_ATR
);
155 /* The 6bit value in the ATR register controls the load
156 * capacitance C_load * in steps of 0.25pF
158 * bit (1<<5) of the ATR register is inverted
160 * C_load(ATR=0x20) = 4.50pF
161 * C_load(ATR=0x00) = 12.50pF
162 * C_load(ATR=0x1f) = 20.25pF
166 atr
&= 0x3f; /* mask out lsb */
167 atr
^= 1 << 5; /* invert 6th bit */
168 atr
+= 2 * 9; /* add offset of 4.5pF; unit[atr] = 0.25pF */
174 isl1208_i2c_get_dtr(struct i2c_client
*client
)
176 int dtr
= i2c_smbus_read_byte_data(client
, ISL1208_REG_DTR
);
180 /* dtr encodes adjustments of {-60,-40,-20,0,20,40,60} ppm */
181 dtr
= ((dtr
& 0x3) * 20) * (dtr
& (1 << 2) ? -1 : 1);
187 isl1208_i2c_get_usr(struct i2c_client
*client
)
189 u8 buf
[ISL1208_USR_SECTION_LEN
] = { 0, };
192 ret
= isl1208_i2c_read_regs(client
, ISL1208_REG_USR1
, buf
,
193 ISL1208_USR_SECTION_LEN
);
197 return (buf
[1] << 8) | buf
[0];
201 isl1208_i2c_set_usr(struct i2c_client
*client
, u16 usr
)
203 u8 buf
[ISL1208_USR_SECTION_LEN
];
206 buf
[1] = (usr
>> 8) & 0xff;
208 return isl1208_i2c_set_regs(client
, ISL1208_REG_USR1
, buf
,
209 ISL1208_USR_SECTION_LEN
);
213 isl1208_rtc_toggle_alarm(struct i2c_client
*client
, int enable
)
215 int icr
= i2c_smbus_read_byte_data(client
, ISL1208_REG_INT
);
218 dev_err(&client
->dev
, "%s: reading INT failed\n", __func__
);
223 icr
|= ISL1208_REG_INT_ALME
| ISL1208_REG_INT_IM
;
225 icr
&= ~(ISL1208_REG_INT_ALME
| ISL1208_REG_INT_IM
);
227 icr
= i2c_smbus_write_byte_data(client
, ISL1208_REG_INT
, icr
);
229 dev_err(&client
->dev
, "%s: writing INT failed\n", __func__
);
237 isl1208_rtc_proc(struct device
*dev
, struct seq_file
*seq
)
239 struct i2c_client
*const client
= to_i2c_client(dev
);
240 int sr
, dtr
, atr
, usr
;
242 sr
= isl1208_i2c_get_sr(client
);
244 dev_err(&client
->dev
, "%s: reading SR failed\n", __func__
);
248 seq_printf(seq
, "status_reg\t:%s%s%s%s%s%s (0x%.2x)\n",
249 (sr
& ISL1208_REG_SR_RTCF
) ? " RTCF" : "",
250 (sr
& ISL1208_REG_SR_BAT
) ? " BAT" : "",
251 (sr
& ISL1208_REG_SR_ALM
) ? " ALM" : "",
252 (sr
& ISL1208_REG_SR_WRTC
) ? " WRTC" : "",
253 (sr
& ISL1208_REG_SR_XTOSCB
) ? " XTOSCB" : "",
254 (sr
& ISL1208_REG_SR_ARST
) ? " ARST" : "", sr
);
256 seq_printf(seq
, "batt_status\t: %s\n",
257 (sr
& ISL1208_REG_SR_RTCF
) ? "bad" : "okay");
259 dtr
= isl1208_i2c_get_dtr(client
);
261 seq_printf(seq
, "digital_trim\t: %d ppm\n", dtr
);
263 atr
= isl1208_i2c_get_atr(client
);
265 seq_printf(seq
, "analog_trim\t: %d.%.2d pF\n",
266 atr
>> 2, (atr
& 0x3) * 25);
268 usr
= isl1208_i2c_get_usr(client
);
270 seq_printf(seq
, "user_data\t: 0x%.4x\n", usr
);
276 isl1208_i2c_read_time(struct i2c_client
*client
, struct rtc_time
*tm
)
279 u8 regs
[ISL1208_RTC_SECTION_LEN
] = { 0, };
281 sr
= isl1208_i2c_get_sr(client
);
283 dev_err(&client
->dev
, "%s: reading SR failed\n", __func__
);
287 sr
= isl1208_i2c_read_regs(client
, 0, regs
, ISL1208_RTC_SECTION_LEN
);
289 dev_err(&client
->dev
, "%s: reading RTC section failed\n",
294 tm
->tm_sec
= bcd2bin(regs
[ISL1208_REG_SC
]);
295 tm
->tm_min
= bcd2bin(regs
[ISL1208_REG_MN
]);
297 /* HR field has a more complex interpretation */
299 const u8 _hr
= regs
[ISL1208_REG_HR
];
300 if (_hr
& ISL1208_REG_HR_MIL
) /* 24h format */
301 tm
->tm_hour
= bcd2bin(_hr
& 0x3f);
304 tm
->tm_hour
= bcd2bin(_hr
& 0x1f);
305 if (_hr
& ISL1208_REG_HR_PM
) /* PM flag set */
310 tm
->tm_mday
= bcd2bin(regs
[ISL1208_REG_DT
]);
311 tm
->tm_mon
= bcd2bin(regs
[ISL1208_REG_MO
]) - 1; /* rtc starts at 1 */
312 tm
->tm_year
= bcd2bin(regs
[ISL1208_REG_YR
]) + 100;
313 tm
->tm_wday
= bcd2bin(regs
[ISL1208_REG_DW
]);
319 isl1208_i2c_read_alarm(struct i2c_client
*client
, struct rtc_wkalrm
*alarm
)
321 struct rtc_time
*const tm
= &alarm
->time
;
322 u8 regs
[ISL1208_ALARM_SECTION_LEN
] = { 0, };
323 int icr
, yr
, sr
= isl1208_i2c_get_sr(client
);
326 dev_err(&client
->dev
, "%s: reading SR failed\n", __func__
);
330 sr
= isl1208_i2c_read_regs(client
, ISL1208_REG_SCA
, regs
,
331 ISL1208_ALARM_SECTION_LEN
);
333 dev_err(&client
->dev
, "%s: reading alarm section failed\n",
338 /* MSB of each alarm register is an enable bit */
339 tm
->tm_sec
= bcd2bin(regs
[ISL1208_REG_SCA
- ISL1208_REG_SCA
] & 0x7f);
340 tm
->tm_min
= bcd2bin(regs
[ISL1208_REG_MNA
- ISL1208_REG_SCA
] & 0x7f);
341 tm
->tm_hour
= bcd2bin(regs
[ISL1208_REG_HRA
- ISL1208_REG_SCA
] & 0x3f);
342 tm
->tm_mday
= bcd2bin(regs
[ISL1208_REG_DTA
- ISL1208_REG_SCA
] & 0x3f);
344 bcd2bin(regs
[ISL1208_REG_MOA
- ISL1208_REG_SCA
] & 0x1f) - 1;
345 tm
->tm_wday
= bcd2bin(regs
[ISL1208_REG_DWA
- ISL1208_REG_SCA
] & 0x03);
347 /* The alarm doesn't store the year so get it from the rtc section */
348 yr
= i2c_smbus_read_byte_data(client
, ISL1208_REG_YR
);
350 dev_err(&client
->dev
, "%s: reading RTC YR failed\n", __func__
);
353 tm
->tm_year
= bcd2bin(yr
) + 100;
355 icr
= i2c_smbus_read_byte_data(client
, ISL1208_REG_INT
);
357 dev_err(&client
->dev
, "%s: reading INT failed\n", __func__
);
360 alarm
->enabled
= !!(icr
& ISL1208_REG_INT_ALME
);
366 isl1208_i2c_set_alarm(struct i2c_client
*client
, struct rtc_wkalrm
*alarm
)
368 struct rtc_time
*alarm_tm
= &alarm
->time
;
369 u8 regs
[ISL1208_ALARM_SECTION_LEN
] = { 0, };
370 const int offs
= ISL1208_REG_SCA
;
371 struct rtc_time rtc_tm
;
374 err
= isl1208_i2c_read_time(client
, &rtc_tm
);
378 /* If the alarm time is before the current time disable the alarm */
379 if (!alarm
->enabled
|| rtc_tm_sub(alarm_tm
, &rtc_tm
) <= 0)
384 /* Program the alarm and enable it for each setting */
385 regs
[ISL1208_REG_SCA
- offs
] = bin2bcd(alarm_tm
->tm_sec
) | enable
;
386 regs
[ISL1208_REG_MNA
- offs
] = bin2bcd(alarm_tm
->tm_min
) | enable
;
387 regs
[ISL1208_REG_HRA
- offs
] = bin2bcd(alarm_tm
->tm_hour
) |
388 ISL1208_REG_HR_MIL
| enable
;
390 regs
[ISL1208_REG_DTA
- offs
] = bin2bcd(alarm_tm
->tm_mday
) | enable
;
391 regs
[ISL1208_REG_MOA
- offs
] = bin2bcd(alarm_tm
->tm_mon
+ 1) | enable
;
392 regs
[ISL1208_REG_DWA
- offs
] = bin2bcd(alarm_tm
->tm_wday
& 7) | enable
;
394 /* write ALARM registers */
395 err
= isl1208_i2c_set_regs(client
, offs
, regs
,
396 ISL1208_ALARM_SECTION_LEN
);
398 dev_err(&client
->dev
, "%s: writing ALARM section failed\n",
403 err
= isl1208_rtc_toggle_alarm(client
, enable
);
411 isl1208_rtc_read_time(struct device
*dev
, struct rtc_time
*tm
)
413 return isl1208_i2c_read_time(to_i2c_client(dev
), tm
);
417 isl1208_i2c_set_time(struct i2c_client
*client
, struct rtc_time
const *tm
)
420 u8 regs
[ISL1208_RTC_SECTION_LEN
] = { 0, };
422 /* The clock has an 8 bit wide bcd-coded register (they never learn)
423 * for the year. tm_year is an offset from 1900 and we are interested
424 * in the 2000-2099 range, so any value less than 100 is invalid.
426 if (tm
->tm_year
< 100)
429 regs
[ISL1208_REG_SC
] = bin2bcd(tm
->tm_sec
);
430 regs
[ISL1208_REG_MN
] = bin2bcd(tm
->tm_min
);
431 regs
[ISL1208_REG_HR
] = bin2bcd(tm
->tm_hour
) | ISL1208_REG_HR_MIL
;
433 regs
[ISL1208_REG_DT
] = bin2bcd(tm
->tm_mday
);
434 regs
[ISL1208_REG_MO
] = bin2bcd(tm
->tm_mon
+ 1);
435 regs
[ISL1208_REG_YR
] = bin2bcd(tm
->tm_year
- 100);
437 regs
[ISL1208_REG_DW
] = bin2bcd(tm
->tm_wday
& 7);
439 sr
= isl1208_i2c_get_sr(client
);
441 dev_err(&client
->dev
, "%s: reading SR failed\n", __func__
);
446 sr
= i2c_smbus_write_byte_data(client
, ISL1208_REG_SR
,
447 sr
| ISL1208_REG_SR_WRTC
);
449 dev_err(&client
->dev
, "%s: writing SR failed\n", __func__
);
453 /* write RTC registers */
454 sr
= isl1208_i2c_set_regs(client
, 0, regs
, ISL1208_RTC_SECTION_LEN
);
456 dev_err(&client
->dev
, "%s: writing RTC section failed\n",
461 /* clear WRTC again */
462 sr
= i2c_smbus_write_byte_data(client
, ISL1208_REG_SR
,
463 sr
& ~ISL1208_REG_SR_WRTC
);
465 dev_err(&client
->dev
, "%s: writing SR failed\n", __func__
);
474 isl1208_rtc_set_time(struct device
*dev
, struct rtc_time
*tm
)
476 return isl1208_i2c_set_time(to_i2c_client(dev
), tm
);
480 isl1208_rtc_read_alarm(struct device
*dev
, struct rtc_wkalrm
*alarm
)
482 return isl1208_i2c_read_alarm(to_i2c_client(dev
), alarm
);
486 isl1208_rtc_set_alarm(struct device
*dev
, struct rtc_wkalrm
*alarm
)
488 return isl1208_i2c_set_alarm(to_i2c_client(dev
), alarm
);
492 isl1208_rtc_interrupt(int irq
, void *data
)
494 unsigned long timeout
= jiffies
+ msecs_to_jiffies(1000);
495 struct i2c_client
*client
= data
;
496 struct rtc_device
*rtc
= i2c_get_clientdata(client
);
497 int handled
= 0, sr
, err
;
500 * I2C reads get NAK'ed if we read straight away after an interrupt?
501 * Using a mdelay/msleep didn't seem to help either, so we work around
502 * this by continually trying to read the register for a short time.
505 sr
= isl1208_i2c_get_sr(client
);
509 if (time_after(jiffies
, timeout
)) {
510 dev_err(&client
->dev
, "%s: reading SR failed\n",
516 if (sr
& ISL1208_REG_SR_ALM
) {
517 dev_dbg(&client
->dev
, "alarm!\n");
519 rtc_update_irq(rtc
, 1, RTC_IRQF
| RTC_AF
);
521 /* Clear the alarm */
522 sr
&= ~ISL1208_REG_SR_ALM
;
523 sr
= i2c_smbus_write_byte_data(client
, ISL1208_REG_SR
, sr
);
525 dev_err(&client
->dev
, "%s: writing SR failed\n",
530 /* Disable the alarm */
531 err
= isl1208_rtc_toggle_alarm(client
, 0);
536 return handled
? IRQ_HANDLED
: IRQ_NONE
;
539 static const struct rtc_class_ops isl1208_rtc_ops
= {
540 .proc
= isl1208_rtc_proc
,
541 .read_time
= isl1208_rtc_read_time
,
542 .set_time
= isl1208_rtc_set_time
,
543 .read_alarm
= isl1208_rtc_read_alarm
,
544 .set_alarm
= isl1208_rtc_set_alarm
,
547 /* sysfs interface */
550 isl1208_sysfs_show_atrim(struct device
*dev
,
551 struct device_attribute
*attr
, char *buf
)
553 int atr
= isl1208_i2c_get_atr(to_i2c_client(dev
));
557 return sprintf(buf
, "%d.%.2d pF\n", atr
>> 2, (atr
& 0x3) * 25);
560 static DEVICE_ATTR(atrim
, S_IRUGO
, isl1208_sysfs_show_atrim
, NULL
);
563 isl1208_sysfs_show_dtrim(struct device
*dev
,
564 struct device_attribute
*attr
, char *buf
)
566 int dtr
= isl1208_i2c_get_dtr(to_i2c_client(dev
));
570 return sprintf(buf
, "%d ppm\n", dtr
);
573 static DEVICE_ATTR(dtrim
, S_IRUGO
, isl1208_sysfs_show_dtrim
, NULL
);
576 isl1208_sysfs_show_usr(struct device
*dev
,
577 struct device_attribute
*attr
, char *buf
)
579 int usr
= isl1208_i2c_get_usr(to_i2c_client(dev
));
583 return sprintf(buf
, "0x%.4x\n", usr
);
587 isl1208_sysfs_store_usr(struct device
*dev
,
588 struct device_attribute
*attr
,
589 const char *buf
, size_t count
)
593 if (buf
[0] == '0' && (buf
[1] == 'x' || buf
[1] == 'X')) {
594 if (sscanf(buf
, "%x", &usr
) != 1)
597 if (sscanf(buf
, "%d", &usr
) != 1)
601 if (usr
< 0 || usr
> 0xffff)
604 return isl1208_i2c_set_usr(to_i2c_client(dev
), usr
) ? -EIO
: count
;
607 static DEVICE_ATTR(usr
, S_IRUGO
| S_IWUSR
, isl1208_sysfs_show_usr
,
608 isl1208_sysfs_store_usr
);
610 static struct attribute
*isl1208_rtc_attrs
[] = {
611 &dev_attr_atrim
.attr
,
612 &dev_attr_dtrim
.attr
,
617 static const struct attribute_group isl1208_rtc_sysfs_files
= {
618 .attrs
= isl1208_rtc_attrs
,
622 isl1208_probe(struct i2c_client
*client
, const struct i2c_device_id
*id
)
625 struct rtc_device
*rtc
;
627 if (!i2c_check_functionality(client
->adapter
, I2C_FUNC_I2C
))
630 if (isl1208_i2c_validate_client(client
) < 0)
633 if (client
->irq
> 0) {
634 rc
= devm_request_threaded_irq(&client
->dev
, client
->irq
, NULL
,
635 isl1208_rtc_interrupt
,
636 IRQF_SHARED
| IRQF_ONESHOT
,
637 isl1208_driver
.driver
.name
,
640 device_init_wakeup(&client
->dev
, 1);
641 enable_irq_wake(client
->irq
);
643 dev_err(&client
->dev
,
644 "Unable to request irq %d, no alarm support\n",
650 rtc
= devm_rtc_device_register(&client
->dev
, isl1208_driver
.driver
.name
,
656 i2c_set_clientdata(client
, rtc
);
658 rc
= isl1208_i2c_get_sr(client
);
660 dev_err(&client
->dev
, "reading status failed\n");
664 if (rc
& ISL1208_REG_SR_RTCF
)
665 dev_warn(&client
->dev
, "rtc power failure detected, "
666 "please set clock.\n");
668 rc
= sysfs_create_group(&client
->dev
.kobj
, &isl1208_rtc_sysfs_files
);
676 isl1208_remove(struct i2c_client
*client
)
678 sysfs_remove_group(&client
->dev
.kobj
, &isl1208_rtc_sysfs_files
);
683 static const struct i2c_device_id isl1208_id
[] = {
688 MODULE_DEVICE_TABLE(i2c
, isl1208_id
);
690 static struct i2c_driver isl1208_driver
= {
692 .name
= "rtc-isl1208",
694 .probe
= isl1208_probe
,
695 .remove
= isl1208_remove
,
696 .id_table
= isl1208_id
,
699 module_i2c_driver(isl1208_driver
);
701 MODULE_AUTHOR("Herbert Valerio Riedel <hvr@gnu.org>");
702 MODULE_DESCRIPTION("Intersil ISL1208 RTC driver");
703 MODULE_LICENSE("GPL");