2 * I2C client/driver for the ST M41T80 family of i2c rtc chips.
4 * Author: Alexander Bigga <ab@mycable.de>
6 * Based on m41t00.c by Mark A. Greer <mgreer@mvista.com>
8 * 2006 (c) mycable GmbH
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2 as
12 * published by the Free Software Foundation.
16 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
18 #include <linux/bcd.h>
19 #include <linux/clk-provider.h>
20 #include <linux/i2c.h>
21 #include <linux/init.h>
22 #include <linux/kernel.h>
23 #include <linux/module.h>
24 #include <linux/of_device.h>
25 #include <linux/rtc.h>
26 #include <linux/slab.h>
27 #include <linux/mutex.h>
28 #include <linux/string.h>
29 #ifdef CONFIG_RTC_DRV_M41T80_WDT
31 #include <linux/ioctl.h>
32 #include <linux/miscdevice.h>
33 #include <linux/reboot.h>
34 #include <linux/watchdog.h>
37 #define M41T80_REG_SSEC 0x00
38 #define M41T80_REG_SEC 0x01
39 #define M41T80_REG_MIN 0x02
40 #define M41T80_REG_HOUR 0x03
41 #define M41T80_REG_WDAY 0x04
42 #define M41T80_REG_DAY 0x05
43 #define M41T80_REG_MON 0x06
44 #define M41T80_REG_YEAR 0x07
45 #define M41T80_REG_ALARM_MON 0x0a
46 #define M41T80_REG_ALARM_DAY 0x0b
47 #define M41T80_REG_ALARM_HOUR 0x0c
48 #define M41T80_REG_ALARM_MIN 0x0d
49 #define M41T80_REG_ALARM_SEC 0x0e
50 #define M41T80_REG_FLAGS 0x0f
51 #define M41T80_REG_SQW 0x13
53 #define M41T80_DATETIME_REG_SIZE (M41T80_REG_YEAR + 1)
54 #define M41T80_ALARM_REG_SIZE \
55 (M41T80_REG_ALARM_SEC + 1 - M41T80_REG_ALARM_MON)
57 #define M41T80_SQW_MAX_FREQ 32768
59 #define M41T80_SEC_ST BIT(7) /* ST: Stop Bit */
60 #define M41T80_ALMON_AFE BIT(7) /* AFE: AF Enable Bit */
61 #define M41T80_ALMON_SQWE BIT(6) /* SQWE: SQW Enable Bit */
62 #define M41T80_ALHOUR_HT BIT(6) /* HT: Halt Update Bit */
63 #define M41T80_FLAGS_OF BIT(2) /* OF: Oscillator Failure Bit */
64 #define M41T80_FLAGS_AF BIT(6) /* AF: Alarm Flag Bit */
65 #define M41T80_FLAGS_BATT_LOW BIT(4) /* BL: Battery Low Bit */
66 #define M41T80_WATCHDOG_RB2 BIT(7) /* RB: Watchdog resolution */
67 #define M41T80_WATCHDOG_RB1 BIT(1) /* RB: Watchdog resolution */
68 #define M41T80_WATCHDOG_RB0 BIT(0) /* RB: Watchdog resolution */
70 #define M41T80_FEATURE_HT BIT(0) /* Halt feature */
71 #define M41T80_FEATURE_BL BIT(1) /* Battery low indicator */
72 #define M41T80_FEATURE_SQ BIT(2) /* Squarewave feature */
73 #define M41T80_FEATURE_WD BIT(3) /* Extra watchdog resolution */
74 #define M41T80_FEATURE_SQ_ALT BIT(4) /* RSx bits are in reg 4 */
76 static DEFINE_MUTEX(m41t80_rtc_mutex
);
77 static const struct i2c_device_id m41t80_id
[] = {
78 { "m41t62", M41T80_FEATURE_SQ
| M41T80_FEATURE_SQ_ALT
},
79 { "m41t65", M41T80_FEATURE_HT
| M41T80_FEATURE_WD
},
80 { "m41t80", M41T80_FEATURE_SQ
},
81 { "m41t81", M41T80_FEATURE_HT
| M41T80_FEATURE_SQ
},
82 { "m41t81s", M41T80_FEATURE_HT
| M41T80_FEATURE_BL
| M41T80_FEATURE_SQ
},
83 { "m41t82", M41T80_FEATURE_HT
| M41T80_FEATURE_BL
| M41T80_FEATURE_SQ
},
84 { "m41t83", M41T80_FEATURE_HT
| M41T80_FEATURE_BL
| M41T80_FEATURE_SQ
},
85 { "m41st84", M41T80_FEATURE_HT
| M41T80_FEATURE_BL
| M41T80_FEATURE_SQ
},
86 { "m41st85", M41T80_FEATURE_HT
| M41T80_FEATURE_BL
| M41T80_FEATURE_SQ
},
87 { "m41st87", M41T80_FEATURE_HT
| M41T80_FEATURE_BL
| M41T80_FEATURE_SQ
},
88 { "rv4162", M41T80_FEATURE_SQ
| M41T80_FEATURE_WD
| M41T80_FEATURE_SQ_ALT
},
91 MODULE_DEVICE_TABLE(i2c
, m41t80_id
);
93 static const struct of_device_id m41t80_of_match
[] = {
95 .compatible
= "st,m41t62",
96 .data
= (void *)(M41T80_FEATURE_SQ
| M41T80_FEATURE_SQ_ALT
)
99 .compatible
= "st,m41t65",
100 .data
= (void *)(M41T80_FEATURE_HT
| M41T80_FEATURE_WD
)
103 .compatible
= "st,m41t80",
104 .data
= (void *)(M41T80_FEATURE_SQ
)
107 .compatible
= "st,m41t81",
108 .data
= (void *)(M41T80_FEATURE_HT
| M41T80_FEATURE_SQ
)
111 .compatible
= "st,m41t81s",
112 .data
= (void *)(M41T80_FEATURE_HT
| M41T80_FEATURE_BL
| M41T80_FEATURE_SQ
)
115 .compatible
= "st,m41t82",
116 .data
= (void *)(M41T80_FEATURE_HT
| M41T80_FEATURE_BL
| M41T80_FEATURE_SQ
)
119 .compatible
= "st,m41t83",
120 .data
= (void *)(M41T80_FEATURE_HT
| M41T80_FEATURE_BL
| M41T80_FEATURE_SQ
)
123 .compatible
= "st,m41t84",
124 .data
= (void *)(M41T80_FEATURE_HT
| M41T80_FEATURE_BL
| M41T80_FEATURE_SQ
)
127 .compatible
= "st,m41t85",
128 .data
= (void *)(M41T80_FEATURE_HT
| M41T80_FEATURE_BL
| M41T80_FEATURE_SQ
)
131 .compatible
= "st,m41t87",
132 .data
= (void *)(M41T80_FEATURE_HT
| M41T80_FEATURE_BL
| M41T80_FEATURE_SQ
)
135 .compatible
= "microcrystal,rv4162",
136 .data
= (void *)(M41T80_FEATURE_SQ
| M41T80_FEATURE_WD
| M41T80_FEATURE_SQ_ALT
)
138 /* DT compatibility only, do not use compatibles below: */
140 .compatible
= "st,rv4162",
141 .data
= (void *)(M41T80_FEATURE_SQ
| M41T80_FEATURE_WD
| M41T80_FEATURE_SQ_ALT
)
144 .compatible
= "rv4162",
145 .data
= (void *)(M41T80_FEATURE_SQ
| M41T80_FEATURE_WD
| M41T80_FEATURE_SQ_ALT
)
149 MODULE_DEVICE_TABLE(of
, m41t80_of_match
);
152 unsigned long features
;
153 struct i2c_client
*client
;
154 struct rtc_device
*rtc
;
155 #ifdef CONFIG_COMMON_CLK
160 static irqreturn_t
m41t80_handle_irq(int irq
, void *dev_id
)
162 struct i2c_client
*client
= dev_id
;
163 struct m41t80_data
*m41t80
= i2c_get_clientdata(client
);
164 struct mutex
*lock
= &m41t80
->rtc
->ops_lock
;
165 unsigned long events
= 0;
166 int flags
, flags_afe
;
170 flags_afe
= i2c_smbus_read_byte_data(client
, M41T80_REG_ALARM_MON
);
176 flags
= i2c_smbus_read_byte_data(client
, M41T80_REG_FLAGS
);
182 if (flags
& M41T80_FLAGS_AF
) {
183 flags
&= ~M41T80_FLAGS_AF
;
184 flags_afe
&= ~M41T80_ALMON_AFE
;
189 rtc_update_irq(m41t80
->rtc
, 1, events
);
190 i2c_smbus_write_byte_data(client
, M41T80_REG_FLAGS
, flags
);
191 i2c_smbus_write_byte_data(client
, M41T80_REG_ALARM_MON
,
200 static int m41t80_get_datetime(struct i2c_client
*client
,
203 unsigned char buf
[8];
206 flags
= i2c_smbus_read_byte_data(client
, M41T80_REG_FLAGS
);
210 if (flags
& M41T80_FLAGS_OF
) {
211 dev_err(&client
->dev
, "Oscillator failure, data is invalid.\n");
215 err
= i2c_smbus_read_i2c_block_data(client
, M41T80_REG_SSEC
,
218 dev_err(&client
->dev
, "Unable to read date\n");
222 tm
->tm_sec
= bcd2bin(buf
[M41T80_REG_SEC
] & 0x7f);
223 tm
->tm_min
= bcd2bin(buf
[M41T80_REG_MIN
] & 0x7f);
224 tm
->tm_hour
= bcd2bin(buf
[M41T80_REG_HOUR
] & 0x3f);
225 tm
->tm_mday
= bcd2bin(buf
[M41T80_REG_DAY
] & 0x3f);
226 tm
->tm_wday
= buf
[M41T80_REG_WDAY
] & 0x07;
227 tm
->tm_mon
= bcd2bin(buf
[M41T80_REG_MON
] & 0x1f) - 1;
229 /* assume 20YY not 19YY, and ignore the Century Bit */
230 tm
->tm_year
= bcd2bin(buf
[M41T80_REG_YEAR
]) + 100;
231 return rtc_valid_tm(tm
);
234 /* Sets the given date and time to the real time clock. */
235 static int m41t80_set_datetime(struct i2c_client
*client
, struct rtc_time
*tm
)
237 struct m41t80_data
*clientdata
= i2c_get_clientdata(client
);
238 unsigned char buf
[8];
241 if (tm
->tm_year
< 100 || tm
->tm_year
> 199)
244 buf
[M41T80_REG_SSEC
] = 0;
245 buf
[M41T80_REG_SEC
] = bin2bcd(tm
->tm_sec
);
246 buf
[M41T80_REG_MIN
] = bin2bcd(tm
->tm_min
);
247 buf
[M41T80_REG_HOUR
] = bin2bcd(tm
->tm_hour
);
248 buf
[M41T80_REG_DAY
] = bin2bcd(tm
->tm_mday
);
249 buf
[M41T80_REG_MON
] = bin2bcd(tm
->tm_mon
+ 1);
250 buf
[M41T80_REG_YEAR
] = bin2bcd(tm
->tm_year
- 100);
251 buf
[M41T80_REG_WDAY
] = tm
->tm_wday
;
253 /* If the square wave output is controlled in the weekday register */
254 if (clientdata
->features
& M41T80_FEATURE_SQ_ALT
) {
257 val
= i2c_smbus_read_byte_data(client
, M41T80_REG_WDAY
);
261 buf
[M41T80_REG_WDAY
] |= (val
& 0xf0);
264 err
= i2c_smbus_write_i2c_block_data(client
, M41T80_REG_SSEC
,
267 dev_err(&client
->dev
, "Unable to write to date registers\n");
271 /* Clear the OF bit of Flags Register */
272 flags
= i2c_smbus_read_byte_data(client
, M41T80_REG_FLAGS
);
276 if (i2c_smbus_write_byte_data(client
, M41T80_REG_FLAGS
,
277 flags
& ~M41T80_FLAGS_OF
)) {
278 dev_err(&client
->dev
, "Unable to write flags register\n");
285 static int m41t80_rtc_proc(struct device
*dev
, struct seq_file
*seq
)
287 struct i2c_client
*client
= to_i2c_client(dev
);
288 struct m41t80_data
*clientdata
= i2c_get_clientdata(client
);
291 if (clientdata
->features
& M41T80_FEATURE_BL
) {
292 reg
= i2c_smbus_read_byte_data(client
, M41T80_REG_FLAGS
);
293 seq_printf(seq
, "battery\t\t: %s\n",
294 (reg
& M41T80_FLAGS_BATT_LOW
) ? "exhausted" : "ok");
299 static int m41t80_rtc_read_time(struct device
*dev
, struct rtc_time
*tm
)
301 return m41t80_get_datetime(to_i2c_client(dev
), tm
);
304 static int m41t80_rtc_set_time(struct device
*dev
, struct rtc_time
*tm
)
306 return m41t80_set_datetime(to_i2c_client(dev
), tm
);
309 static int m41t80_alarm_irq_enable(struct device
*dev
, unsigned int enabled
)
311 struct i2c_client
*client
= to_i2c_client(dev
);
314 flags
= i2c_smbus_read_byte_data(client
, M41T80_REG_ALARM_MON
);
319 flags
|= M41T80_ALMON_AFE
;
321 flags
&= ~M41T80_ALMON_AFE
;
323 retval
= i2c_smbus_write_byte_data(client
, M41T80_REG_ALARM_MON
, flags
);
325 dev_err(dev
, "Unable to enable alarm IRQ %d\n", retval
);
331 static int m41t80_set_alarm(struct device
*dev
, struct rtc_wkalrm
*alrm
)
333 struct i2c_client
*client
= to_i2c_client(dev
);
337 alarmvals
[0] = bin2bcd(alrm
->time
.tm_mon
+ 1);
338 alarmvals
[1] = bin2bcd(alrm
->time
.tm_mday
);
339 alarmvals
[2] = bin2bcd(alrm
->time
.tm_hour
);
340 alarmvals
[3] = bin2bcd(alrm
->time
.tm_min
);
341 alarmvals
[4] = bin2bcd(alrm
->time
.tm_sec
);
343 /* Clear AF and AFE flags */
344 ret
= i2c_smbus_read_byte_data(client
, M41T80_REG_ALARM_MON
);
347 err
= i2c_smbus_write_byte_data(client
, M41T80_REG_ALARM_MON
,
348 ret
& ~(M41T80_ALMON_AFE
));
350 dev_err(dev
, "Unable to clear AFE bit\n");
354 /* Keep SQWE bit value */
355 alarmvals
[0] |= (ret
& M41T80_ALMON_SQWE
);
357 ret
= i2c_smbus_read_byte_data(client
, M41T80_REG_FLAGS
);
361 err
= i2c_smbus_write_byte_data(client
, M41T80_REG_FLAGS
,
362 ret
& ~(M41T80_FLAGS_AF
));
364 dev_err(dev
, "Unable to clear AF bit\n");
368 /* Write the alarm */
369 err
= i2c_smbus_write_i2c_block_data(client
, M41T80_REG_ALARM_MON
,
374 /* Enable the alarm interrupt */
376 alarmvals
[0] |= M41T80_ALMON_AFE
;
377 err
= i2c_smbus_write_byte_data(client
, M41T80_REG_ALARM_MON
,
386 static int m41t80_read_alarm(struct device
*dev
, struct rtc_wkalrm
*alrm
)
388 struct i2c_client
*client
= to_i2c_client(dev
);
392 ret
= i2c_smbus_read_i2c_block_data(client
, M41T80_REG_ALARM_MON
,
395 return ret
< 0 ? ret
: -EIO
;
397 flags
= i2c_smbus_read_byte_data(client
, M41T80_REG_FLAGS
);
401 alrm
->time
.tm_sec
= bcd2bin(alarmvals
[4] & 0x7f);
402 alrm
->time
.tm_min
= bcd2bin(alarmvals
[3] & 0x7f);
403 alrm
->time
.tm_hour
= bcd2bin(alarmvals
[2] & 0x3f);
404 alrm
->time
.tm_mday
= bcd2bin(alarmvals
[1] & 0x3f);
405 alrm
->time
.tm_mon
= bcd2bin(alarmvals
[0] & 0x3f);
407 alrm
->enabled
= !!(alarmvals
[0] & M41T80_ALMON_AFE
);
408 alrm
->pending
= (flags
& M41T80_FLAGS_AF
) && alrm
->enabled
;
413 static struct rtc_class_ops m41t80_rtc_ops
= {
414 .read_time
= m41t80_rtc_read_time
,
415 .set_time
= m41t80_rtc_set_time
,
416 .proc
= m41t80_rtc_proc
,
419 #ifdef CONFIG_PM_SLEEP
420 static int m41t80_suspend(struct device
*dev
)
422 struct i2c_client
*client
= to_i2c_client(dev
);
424 if (client
->irq
>= 0 && device_may_wakeup(dev
))
425 enable_irq_wake(client
->irq
);
430 static int m41t80_resume(struct device
*dev
)
432 struct i2c_client
*client
= to_i2c_client(dev
);
434 if (client
->irq
>= 0 && device_may_wakeup(dev
))
435 disable_irq_wake(client
->irq
);
441 static SIMPLE_DEV_PM_OPS(m41t80_pm
, m41t80_suspend
, m41t80_resume
);
443 static ssize_t
flags_show(struct device
*dev
,
444 struct device_attribute
*attr
, char *buf
)
446 struct i2c_client
*client
= to_i2c_client(dev
);
449 val
= i2c_smbus_read_byte_data(client
, M41T80_REG_FLAGS
);
452 return sprintf(buf
, "%#x\n", val
);
454 static DEVICE_ATTR_RO(flags
);
456 static struct attribute
*attrs
[] = {
457 &dev_attr_flags
.attr
,
461 static struct attribute_group attr_group
= {
465 #ifdef CONFIG_COMMON_CLK
466 #define sqw_to_m41t80_data(_hw) container_of(_hw, struct m41t80_data, sqw)
468 static unsigned long m41t80_sqw_recalc_rate(struct clk_hw
*hw
,
469 unsigned long parent_rate
)
471 struct m41t80_data
*m41t80
= sqw_to_m41t80_data(hw
);
472 struct i2c_client
*client
= m41t80
->client
;
473 int reg_sqw
= (m41t80
->features
& M41T80_FEATURE_SQ_ALT
) ?
474 M41T80_REG_WDAY
: M41T80_REG_SQW
;
475 int ret
= i2c_smbus_read_byte_data(client
, reg_sqw
);
476 unsigned long val
= M41T80_SQW_MAX_FREQ
;
485 val
= val
/ (1 << ret
);
490 static long m41t80_sqw_round_rate(struct clk_hw
*hw
, unsigned long rate
,
491 unsigned long *prate
)
493 int i
, freq
= M41T80_SQW_MAX_FREQ
;
498 for (i
= 2; i
<= ilog2(M41T80_SQW_MAX_FREQ
); i
++) {
507 static int m41t80_sqw_set_rate(struct clk_hw
*hw
, unsigned long rate
,
508 unsigned long parent_rate
)
510 struct m41t80_data
*m41t80
= sqw_to_m41t80_data(hw
);
511 struct i2c_client
*client
= m41t80
->client
;
512 int reg_sqw
= (m41t80
->features
& M41T80_FEATURE_SQ_ALT
) ?
513 M41T80_REG_WDAY
: M41T80_REG_SQW
;
514 int reg
, ret
, val
= 0;
517 if (!is_power_of_2(rate
))
520 if (val
== ilog2(M41T80_SQW_MAX_FREQ
))
522 else if (val
< (ilog2(M41T80_SQW_MAX_FREQ
) - 1))
523 val
= ilog2(M41T80_SQW_MAX_FREQ
) - val
;
528 reg
= i2c_smbus_read_byte_data(client
, reg_sqw
);
532 reg
= (reg
& 0x0f) | (val
<< 4);
534 ret
= i2c_smbus_write_byte_data(client
, reg_sqw
, reg
);
541 static int m41t80_sqw_control(struct clk_hw
*hw
, bool enable
)
543 struct m41t80_data
*m41t80
= sqw_to_m41t80_data(hw
);
544 struct i2c_client
*client
= m41t80
->client
;
545 int ret
= i2c_smbus_read_byte_data(client
, M41T80_REG_ALARM_MON
);
551 ret
|= M41T80_ALMON_SQWE
;
553 ret
&= ~M41T80_ALMON_SQWE
;
555 return i2c_smbus_write_byte_data(client
, M41T80_REG_ALARM_MON
, ret
);
558 static int m41t80_sqw_prepare(struct clk_hw
*hw
)
560 return m41t80_sqw_control(hw
, 1);
563 static void m41t80_sqw_unprepare(struct clk_hw
*hw
)
565 m41t80_sqw_control(hw
, 0);
568 static int m41t80_sqw_is_prepared(struct clk_hw
*hw
)
570 struct m41t80_data
*m41t80
= sqw_to_m41t80_data(hw
);
571 struct i2c_client
*client
= m41t80
->client
;
572 int ret
= i2c_smbus_read_byte_data(client
, M41T80_REG_ALARM_MON
);
577 return !!(ret
& M41T80_ALMON_SQWE
);
580 static const struct clk_ops m41t80_sqw_ops
= {
581 .prepare
= m41t80_sqw_prepare
,
582 .unprepare
= m41t80_sqw_unprepare
,
583 .is_prepared
= m41t80_sqw_is_prepared
,
584 .recalc_rate
= m41t80_sqw_recalc_rate
,
585 .round_rate
= m41t80_sqw_round_rate
,
586 .set_rate
= m41t80_sqw_set_rate
,
589 static struct clk
*m41t80_sqw_register_clk(struct m41t80_data
*m41t80
)
591 struct i2c_client
*client
= m41t80
->client
;
592 struct device_node
*node
= client
->dev
.of_node
;
594 struct clk_init_data init
;
597 /* First disable the clock */
598 ret
= i2c_smbus_read_byte_data(client
, M41T80_REG_ALARM_MON
);
601 ret
= i2c_smbus_write_byte_data(client
, M41T80_REG_ALARM_MON
,
602 ret
& ~(M41T80_ALMON_SQWE
));
606 init
.name
= "m41t80-sqw";
607 init
.ops
= &m41t80_sqw_ops
;
609 init
.parent_names
= NULL
;
610 init
.num_parents
= 0;
611 m41t80
->sqw
.init
= &init
;
613 /* optional override of the clockname */
614 of_property_read_string(node
, "clock-output-names", &init
.name
);
616 /* register the clock */
617 clk
= clk_register(&client
->dev
, &m41t80
->sqw
);
619 of_clk_add_provider(node
, of_clk_src_simple_get
, clk
);
625 #ifdef CONFIG_RTC_DRV_M41T80_WDT
627 *****************************************************************************
631 *****************************************************************************
633 static struct i2c_client
*save_client
;
636 #define WD_TIMO 60 /* 1..31 seconds */
638 static int wdt_margin
= WD_TIMO
;
639 module_param(wdt_margin
, int, 0);
640 MODULE_PARM_DESC(wdt_margin
, "Watchdog timeout in seconds (default 60s)");
642 static unsigned long wdt_is_open
;
643 static int boot_flag
;
648 * Reload counter one with the watchdog timeout. We don't bother reloading
649 * the cascade counter.
651 static void wdt_ping(void)
653 unsigned char i2c_data
[2];
654 struct i2c_msg msgs1
[1] = {
656 .addr
= save_client
->addr
,
662 struct m41t80_data
*clientdata
= i2c_get_clientdata(save_client
);
664 i2c_data
[0] = 0x09; /* watchdog register */
667 i2c_data
[1] = (wdt_margin
& 0xFC) | 0x83; /* resolution = 4s */
670 * WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02)
672 i2c_data
[1] = wdt_margin
<< 2 | 0x82;
675 * M41T65 has three bits for watchdog resolution. Don't set bit 7, as
676 * that would be an invalid resolution.
678 if (clientdata
->features
& M41T80_FEATURE_WD
)
679 i2c_data
[1] &= ~M41T80_WATCHDOG_RB2
;
681 i2c_transfer(save_client
->adapter
, msgs1
, 1);
689 static void wdt_disable(void)
691 unsigned char i2c_data
[2], i2c_buf
[0x10];
692 struct i2c_msg msgs0
[2] = {
694 .addr
= save_client
->addr
,
700 .addr
= save_client
->addr
,
706 struct i2c_msg msgs1
[1] = {
708 .addr
= save_client
->addr
,
716 i2c_transfer(save_client
->adapter
, msgs0
, 2);
720 i2c_transfer(save_client
->adapter
, msgs1
, 1);
725 * @file: file handle to the watchdog
726 * @buf: buffer to write (unused as data does not matter here
727 * @count: count of bytes
728 * @ppos: pointer to the position to write. No seeks allowed
730 * A write to a watchdog device is defined as a keepalive signal. Any
731 * write of data will do, as we we don't define content meaning.
733 static ssize_t
wdt_write(struct file
*file
, const char __user
*buf
,
734 size_t count
, loff_t
*ppos
)
743 static ssize_t
wdt_read(struct file
*file
, char __user
*buf
,
744 size_t count
, loff_t
*ppos
)
751 * @inode: inode of the device
752 * @file: file handle to the device
753 * @cmd: watchdog command
754 * @arg: argument pointer
756 * The watchdog API defines a common set of functions for all watchdogs
757 * according to their available features. We only actually usefully support
758 * querying capabilities and current status.
760 static int wdt_ioctl(struct file
*file
, unsigned int cmd
,
764 static struct watchdog_info ident
= {
765 .options
= WDIOF_POWERUNDER
| WDIOF_KEEPALIVEPING
|
767 .firmware_version
= 1,
768 .identity
= "M41T80 WTD"
772 case WDIOC_GETSUPPORT
:
773 return copy_to_user((struct watchdog_info __user
*)arg
, &ident
,
774 sizeof(ident
)) ? -EFAULT
: 0;
776 case WDIOC_GETSTATUS
:
777 case WDIOC_GETBOOTSTATUS
:
778 return put_user(boot_flag
, (int __user
*)arg
);
779 case WDIOC_KEEPALIVE
:
782 case WDIOC_SETTIMEOUT
:
783 if (get_user(new_margin
, (int __user
*)arg
))
785 /* Arbitrary, can't find the card's limits */
786 if (new_margin
< 1 || new_margin
> 124)
788 wdt_margin
= new_margin
;
791 case WDIOC_GETTIMEOUT
:
792 return put_user(wdt_margin
, (int __user
*)arg
);
794 case WDIOC_SETOPTIONS
:
795 if (copy_from_user(&rv
, (int __user
*)arg
, sizeof(int)))
798 if (rv
& WDIOS_DISABLECARD
) {
799 pr_info("disable watchdog\n");
803 if (rv
& WDIOS_ENABLECARD
) {
804 pr_info("enable watchdog\n");
813 static long wdt_unlocked_ioctl(struct file
*file
, unsigned int cmd
,
818 mutex_lock(&m41t80_rtc_mutex
);
819 ret
= wdt_ioctl(file
, cmd
, arg
);
820 mutex_unlock(&m41t80_rtc_mutex
);
827 * @inode: inode of device
828 * @file: file handle to device
831 static int wdt_open(struct inode
*inode
, struct file
*file
)
833 if (MINOR(inode
->i_rdev
) == WATCHDOG_MINOR
) {
834 mutex_lock(&m41t80_rtc_mutex
);
835 if (test_and_set_bit(0, &wdt_is_open
)) {
836 mutex_unlock(&m41t80_rtc_mutex
);
843 mutex_unlock(&m41t80_rtc_mutex
);
844 return nonseekable_open(inode
, file
);
851 * @inode: inode to board
852 * @file: file handle to board
855 static int wdt_release(struct inode
*inode
, struct file
*file
)
857 if (MINOR(inode
->i_rdev
) == WATCHDOG_MINOR
)
858 clear_bit(0, &wdt_is_open
);
864 * @this: our notifier block
865 * @code: the event being reported
868 * Our notifier is called on system shutdowns. We want to turn the card
869 * off at reboot otherwise the machine will reboot again during memory
870 * test or worse yet during the following fsck. This would suck, in fact
871 * trust me - if it happens it does suck.
873 static int wdt_notify_sys(struct notifier_block
*this, unsigned long code
,
876 if (code
== SYS_DOWN
|| code
== SYS_HALT
)
877 /* Disable Watchdog */
882 static const struct file_operations wdt_fops
= {
883 .owner
= THIS_MODULE
,
885 .unlocked_ioctl
= wdt_unlocked_ioctl
,
888 .release
= wdt_release
,
892 static struct miscdevice wdt_dev
= {
893 .minor
= WATCHDOG_MINOR
,
899 * The WDT card needs to learn about soft shutdowns in order to
900 * turn the timebomb registers off.
902 static struct notifier_block wdt_notifier
= {
903 .notifier_call
= wdt_notify_sys
,
905 #endif /* CONFIG_RTC_DRV_M41T80_WDT */
908 *****************************************************************************
912 *****************************************************************************
915 static void m41t80_remove_sysfs_group(void *_dev
)
917 struct device
*dev
= _dev
;
919 sysfs_remove_group(&dev
->kobj
, &attr_group
);
922 static int m41t80_probe(struct i2c_client
*client
,
923 const struct i2c_device_id
*id
)
925 struct i2c_adapter
*adapter
= to_i2c_adapter(client
->dev
.parent
);
927 struct rtc_device
*rtc
= NULL
;
929 struct m41t80_data
*m41t80_data
= NULL
;
931 if (!i2c_check_functionality(client
->adapter
, I2C_FUNC_SMBUS_I2C_BLOCK
|
932 I2C_FUNC_SMBUS_BYTE_DATA
)) {
933 dev_err(&adapter
->dev
, "doesn't support I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK\n");
937 m41t80_data
= devm_kzalloc(&client
->dev
, sizeof(*m41t80_data
),
942 m41t80_data
->client
= client
;
943 if (client
->dev
.of_node
)
944 m41t80_data
->features
= (unsigned long)
945 of_device_get_match_data(&client
->dev
);
947 m41t80_data
->features
= id
->driver_data
;
948 i2c_set_clientdata(client
, m41t80_data
);
950 if (client
->irq
> 0) {
951 rc
= devm_request_threaded_irq(&client
->dev
, client
->irq
,
952 NULL
, m41t80_handle_irq
,
953 IRQF_TRIGGER_LOW
| IRQF_ONESHOT
,
956 dev_warn(&client
->dev
, "unable to request IRQ, alarms disabled\n");
959 m41t80_rtc_ops
.read_alarm
= m41t80_read_alarm
;
960 m41t80_rtc_ops
.set_alarm
= m41t80_set_alarm
;
961 m41t80_rtc_ops
.alarm_irq_enable
= m41t80_alarm_irq_enable
;
962 /* Enable the wakealarm */
963 device_init_wakeup(&client
->dev
, true);
967 rtc
= devm_rtc_device_register(&client
->dev
, client
->name
,
968 &m41t80_rtc_ops
, THIS_MODULE
);
972 m41t80_data
->rtc
= rtc
;
974 /* Make sure HT (Halt Update) bit is cleared */
975 rc
= i2c_smbus_read_byte_data(client
, M41T80_REG_ALARM_HOUR
);
977 if (rc
>= 0 && rc
& M41T80_ALHOUR_HT
) {
978 if (m41t80_data
->features
& M41T80_FEATURE_HT
) {
979 m41t80_get_datetime(client
, &tm
);
980 dev_info(&client
->dev
, "HT bit was set!\n");
981 dev_info(&client
->dev
,
982 "Power Down at %04i-%02i-%02i %02i:%02i:%02i\n",
984 tm
.tm_mon
+ 1, tm
.tm_mday
, tm
.tm_hour
,
985 tm
.tm_min
, tm
.tm_sec
);
987 rc
= i2c_smbus_write_byte_data(client
, M41T80_REG_ALARM_HOUR
,
988 rc
& ~M41T80_ALHOUR_HT
);
992 dev_err(&client
->dev
, "Can't clear HT bit\n");
996 /* Make sure ST (stop) bit is cleared */
997 rc
= i2c_smbus_read_byte_data(client
, M41T80_REG_SEC
);
999 if (rc
>= 0 && rc
& M41T80_SEC_ST
)
1000 rc
= i2c_smbus_write_byte_data(client
, M41T80_REG_SEC
,
1001 rc
& ~M41T80_SEC_ST
);
1003 dev_err(&client
->dev
, "Can't clear ST bit\n");
1007 /* Export sysfs entries */
1008 rc
= sysfs_create_group(&(&client
->dev
)->kobj
, &attr_group
);
1010 dev_err(&client
->dev
, "Failed to create sysfs group: %d\n", rc
);
1014 rc
= devm_add_action_or_reset(&client
->dev
, m41t80_remove_sysfs_group
,
1017 dev_err(&client
->dev
,
1018 "Failed to add sysfs cleanup action: %d\n", rc
);
1022 #ifdef CONFIG_RTC_DRV_M41T80_WDT
1023 if (m41t80_data
->features
& M41T80_FEATURE_HT
) {
1024 save_client
= client
;
1025 rc
= misc_register(&wdt_dev
);
1028 rc
= register_reboot_notifier(&wdt_notifier
);
1030 misc_deregister(&wdt_dev
);
1035 #ifdef CONFIG_COMMON_CLK
1036 if (m41t80_data
->features
& M41T80_FEATURE_SQ
)
1037 m41t80_sqw_register_clk(m41t80_data
);
1042 static int m41t80_remove(struct i2c_client
*client
)
1044 #ifdef CONFIG_RTC_DRV_M41T80_WDT
1045 struct m41t80_data
*clientdata
= i2c_get_clientdata(client
);
1047 if (clientdata
->features
& M41T80_FEATURE_HT
) {
1048 misc_deregister(&wdt_dev
);
1049 unregister_reboot_notifier(&wdt_notifier
);
1056 static struct i2c_driver m41t80_driver
= {
1058 .name
= "rtc-m41t80",
1059 .of_match_table
= of_match_ptr(m41t80_of_match
),
1062 .probe
= m41t80_probe
,
1063 .remove
= m41t80_remove
,
1064 .id_table
= m41t80_id
,
1067 module_i2c_driver(m41t80_driver
);
1069 MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>");
1070 MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver");
1071 MODULE_LICENSE("GPL");