[PATCH] watchdog: prevent the STPMIC1 watchdog probe from modifying the global turn-OFF behaviour

[PATCH] watchdog: prevent the STPMIC1 watchdog probe from modifying the global turn-OFF behaviour

[Leonard Göhrs]

According to Table 12 in the STPMIC1-datasheet (Rev 7 - December 2020)
there are the following turn-OFF conditions:

- Software switch-OFF*
- PONKEYn long key press*
- Thermal shutdown
- Overcurrent protection
- Watchdog*
- VIN_OK_Fall*

The conditions marked with an * can be re-configured from turn-Off conditions
to restart requests using the RREQ_EN-bit in the CR register
(Called RESTART_REQUEST_ENABLED in Linux/Barebox).

The watchdog code enabled this bit in it's probe function to trigger a restart
on a watchdog event. This may however result in unexpected behaviour,
like a long-press of the PONKEY resulting in a restart instead of a turn-off
when the watchdog is enabled vs. when it is not.

This change does not affect the restart and poweroff functionality provided by
the wdt driver, as the restart-/poweroff-handlers explicitly set/clear the
RESTART_REQUEST_ENABLED flag when triggering a software turn-OFF.

To prevent unexpected behaviour of the PONKEYn and other turn-OFF sources the
RESTART_REQUEST_ENABLED configuration in the probe function can and should thus be removed.

Signed-off-by: Leonard Göhrs <l.goehrs@pengutronix.de>
---
 drivers/watchdog/stpmic1_wdt.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/drivers/watchdog/stpmic1_wdt.c b/drivers/watchdog/stpmic1_wdt.c
index 12280f144..105ba39fb 100644
--- a/drivers/watchdog/stpmic1_wdt.c
+++ b/drivers/watchdog/stpmic1_wdt.c
@@ -174,10 +174,6 @@ static int stpmic1_wdt_probe(struct device_d *dev)
 	wdd->set_timeout = stpmic1_wdt_set_timeout;
 	wdd->timeout_max = PMIC_WDT_MAX_TIMEOUT;
 
-	/* have the watchdog reset, not power-off the system */
-	regmap_write_bits(wdt->regmap, SWOFF_PWRCTRL_CR,
-			  RESTART_REQUEST_ENABLED, RESTART_REQUEST_ENABLED);
-
 	ret = watchdog_register(wdd);
 	if (ret) {
 		dev_err(dev, "Failed to register watchdog device\n");
-- 
2.20.1


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Re: [PATCH] watchdog: prevent the STPMIC1 watchdog probe from modifying the global turn-OFF behaviour

[Leonard Goehrs]

It turns out that the subject line used in the original commit is
rather long and may be truncated when viewed using git log --oneline.

I would thus propose changing it to something shorter, like:

  stpmic1-wdt: don't modify global turn-off behaviour in probe

before applying it.

Sorry for the inconvenience caused
Leonard

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Re: [PATCH] watchdog: prevent the STPMIC1 watchdog probe from modifying the global turn-OFF behaviour

[Ahmad Fatoum]

Hello

On 11.02.21 16:03, Leonard Göhrs wrote:
> According to Table 12 in the STPMIC1-datasheet (Rev 7 - December 2020)
> there are the following turn-OFF conditions:
> 
> - Software switch-OFF*
> - PONKEYn long key press*
> - Thermal shutdown
> - Overcurrent protection
> - Watchdog*
> - VIN_OK_Fall*
> 
> The conditions marked with an * can be re-configured from turn-Off conditions
> to restart requests using the RREQ_EN-bit in the CR register
> (Called RESTART_REQUEST_ENABLED in Linux/Barebox).
> 
> The watchdog code enabled this bit in it's probe function to trigger a restart
> on a watchdog event. This may however result in unexpected behaviour,
> like a long-press of the PONKEY resulting in a restart instead of a turn-off
> when the watchdog is enabled vs. when it is not.
> 
> This change does not affect the restart and poweroff functionality provided by
> the wdt driver, as the restart-/poweroff-handlers explicitly set/clear the
> RESTART_REQUEST_ENABLED flag when triggering a software turn-OFF.
> 
> To prevent unexpected behaviour of the PONKEYn and other turn-OFF sources the
> RESTART_REQUEST_ENABLED configuration in the probe function can and should thus be removed.
> 
> Signed-off-by: Leonard Göhrs <l.goehrs@pengutronix.de>

Reviewed-by: Ahmad Fatoum <a.fatoum@pengutronix.de>

> ---
>  drivers/watchdog/stpmic1_wdt.c | 4 ----
>  1 file changed, 4 deletions(-)
> 
> diff --git a/drivers/watchdog/stpmic1_wdt.c b/drivers/watchdog/stpmic1_wdt.c
> index 12280f144..105ba39fb 100644
> --- a/drivers/watchdog/stpmic1_wdt.c
> +++ b/drivers/watchdog/stpmic1_wdt.c
> @@ -174,10 +174,6 @@ static int stpmic1_wdt_probe(struct device_d *dev)
>  	wdd->set_timeout = stpmic1_wdt_set_timeout;
>  	wdd->timeout_max = PMIC_WDT_MAX_TIMEOUT;
>  
> -	/* have the watchdog reset, not power-off the system */
> -	regmap_write_bits(wdt->regmap, SWOFF_PWRCTRL_CR,
> -			  RESTART_REQUEST_ENABLED, RESTART_REQUEST_ENABLED);
> -
>  	ret = watchdog_register(wdd);
>  	if (ret) {
>  		dev_err(dev, "Failed to register watchdog device\n");
> 

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Pengutronix e.K.                           |                             |
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Re: [PATCH] watchdog: prevent the STPMIC1 watchdog probe from modifying the global turn-OFF behaviour

[Sascha Hauer]

On Thu, Feb 11, 2021 at 04:03:48PM +0100, Leonard Göhrs wrote:
> According to Table 12 in the STPMIC1-datasheet (Rev 7 - December 2020)
> there are the following turn-OFF conditions:
> 
> - Software switch-OFF*
> - PONKEYn long key press*
> - Thermal shutdown
> - Overcurrent protection
> - Watchdog*
> - VIN_OK_Fall*
> 
> The conditions marked with an * can be re-configured from turn-Off conditions
> to restart requests using the RREQ_EN-bit in the CR register
> (Called RESTART_REQUEST_ENABLED in Linux/Barebox).
> 
> The watchdog code enabled this bit in it's probe function to trigger a restart
> on a watchdog event. This may however result in unexpected behaviour,
> like a long-press of the PONKEY resulting in a restart instead of a turn-off
> when the watchdog is enabled vs. when it is not.
> 
> This change does not affect the restart and poweroff functionality provided by
> the wdt driver, as the restart-/poweroff-handlers explicitly set/clear the
> RESTART_REQUEST_ENABLED flag when triggering a software turn-OFF.
> 
> To prevent unexpected behaviour of the PONKEYn and other turn-OFF sources the
> RESTART_REQUEST_ENABLED configuration in the probe function can and should thus be removed.
> 
> Signed-off-by: Leonard Göhrs <l.goehrs@pengutronix.de>
> ---
>  drivers/watchdog/stpmic1_wdt.c | 4 ----
>  1 file changed, 4 deletions(-)

Applied, thanks

Sascha

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

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