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* [PATCH v2] rtc: ds1307: provide an indication that the watchdog has fired
@ 2020-07-26 23:13 Chris Packham
  2020-07-27  3:15 ` Guenter Roeck
  0 siblings, 1 reply; 2+ messages in thread
From: Chris Packham @ 2020-07-26 23:13 UTC (permalink / raw)
  To: a.zummo, alexandre.belloni, linux
  Cc: linux-rtc, linux-watchdog, linux-kernel, Chris Packham

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


^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: [PATCH v2] rtc: ds1307: provide an indication that the watchdog has fired
  2020-07-26 23:13 [PATCH v2] rtc: ds1307: provide an indication that the watchdog has fired Chris Packham
@ 2020-07-27  3:15 ` Guenter Roeck
  0 siblings, 0 replies; 2+ messages in thread
From: Guenter Roeck @ 2020-07-27  3:15 UTC (permalink / raw)
  To: Chris Packham
  Cc: a.zummo, alexandre.belloni, linux-rtc, linux-watchdog, linux-kernel

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
> 

^ permalink raw reply	[flat|nested] 2+ messages in thread

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2020-07-26 23:13 [PATCH v2] rtc: ds1307: provide an indication that the watchdog has fired Chris Packham
2020-07-27  3:15 ` Guenter Roeck

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