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[v2] rtc: ds1307: provide an indication that the watchdog has fired

Message ID 20200726231306.734-1-chris.packham@alliedtelesis.co.nz
State Superseded
Headers show
Series [v2] rtc: ds1307: provide an indication that the watchdog has fired | expand

Commit Message

Chris Packham July 26, 2020, 11:13 p.m. UTC
There's not much feedback when the ds1388 watchdog fires. Generally it
yanks on the reset line and the board reboots. Capture the fact that the
watchdog has fired in the past so that userspace can retrieve it via
WDIOC_GETBOOTSTATUS. This should help distinguish a watchdog triggered
reset from a power interruption.

Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
---
Changes in v2:
- Set bootstatus to WDIOF_CARDRESET and let userspace decide what to do with
  the information.

 drivers/rtc/rtc-ds1307.c | 8 ++++++++
 1 file changed, 8 insertions(+)

Comments

Guenter Roeck July 27, 2020, 3:15 a.m. UTC | #1
On Mon, Jul 27, 2020 at 11:13:06AM +1200, Chris Packham wrote:
> There's not much feedback when the ds1388 watchdog fires. Generally it
> yanks on the reset line and the board reboots. Capture the fact that the
> watchdog has fired in the past so that userspace can retrieve it via
> WDIOC_GETBOOTSTATUS. This should help distinguish a watchdog triggered
> reset from a power interruption.
> 
> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
> ---
> Changes in v2:
> - Set bootstatus to WDIOF_CARDRESET and let userspace decide what to do with
>   the information.
> 
>  drivers/rtc/rtc-ds1307.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
> index 49702942bb08..209736db510d 100644
> --- a/drivers/rtc/rtc-ds1307.c
> +++ b/drivers/rtc/rtc-ds1307.c
> @@ -868,6 +868,14 @@ static int ds1388_wdt_start(struct watchdog_device *wdt_dev)
>  	struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
>  	u8 regs[2];
>  	int ret;
> +	int val;
> +
> +	ret = regmap_read(ds1307->regmap, DS1388_REG_FLAG, &val);
> +	if (ret)
> +		return ret;
> +
> +	if (val & DS1388_BIT_WF)
> +		wdt_dev->bootstatus = WDIOF_CARDRESET;

This should be done during probe, ie in ds1307_wdt_register().

Guenter

>  
>  	ret = regmap_update_bits(ds1307->regmap, DS1388_REG_FLAG,
>  				 DS1388_BIT_WF, 0);
> -- 
> 2.27.0
>
diff mbox series

Patch

diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
index 49702942bb08..209736db510d 100644
--- a/drivers/rtc/rtc-ds1307.c
+++ b/drivers/rtc/rtc-ds1307.c
@@ -868,6 +868,14 @@  static int ds1388_wdt_start(struct watchdog_device *wdt_dev)
 	struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
 	u8 regs[2];
 	int ret;
+	int val;
+
+	ret = regmap_read(ds1307->regmap, DS1388_REG_FLAG, &val);
+	if (ret)
+		return ret;
+
+	if (val & DS1388_BIT_WF)
+		wdt_dev->bootstatus = WDIOF_CARDRESET;
 
 	ret = regmap_update_bits(ds1307->regmap, DS1388_REG_FLAG,
 				 DS1388_BIT_WF, 0);