[PATCHv2 1/2] dts: Documentation: AT91 Watchdog, explain what atmel,idle-halt property really do

Boris Brezillon
2015-01-22T18:14:03Z

On Sun, 18 Jan 2015 14:26:50 +0100
Sylvain Rochet <sylvain.rochet@finsecur.com> wrote:

> atmel,idle-halt property should be used with care, it actually makes the
> watchdog not counting when the CPU is in idle state, therefore the
> watchdog reset time depends on mean CPU usage and will not reset at all
> of the CPU stop working while it is in idle state, which is probably not
> what you want.
>
> Signed-off-by: Sylvain Rochet <sylvain.rochet@finsecur.com>

Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>

> ---
> Documentation/devicetree/bindings/watchdog/atmel-wdt.txt | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/watchdog/atmel-wdt.txt b/Documentation/devicetree/bindings/watchdog/atmel-wdt.txt
> index f90e294..a4d8697 100644
> --- a/Documentation/devicetree/bindings/watchdog/atmel-wdt.txt
> +++ b/Documentation/devicetree/bindings/watchdog/atmel-wdt.txt
> @@ -26,6 +26,11 @@ Optional properties:
> - atmel,disable : Should be present if you want to disable the watchdog.
> - atmel,idle-halt : Should be present if you want to stop the watchdog when
> entering idle state.
> + CAUTION: This property should be used with care, it actually makes the
> + watchdog not counting when the CPU is in idle state, therefore the
> + watchdog reset time depends on mean CPU usage and will not reset at all
> + if the CPU stop working while it is in idle state, which is probably
> + not what you want.
> - atmel,dbg-halt : Should be present if you want to stop the watchdog when
> entering debug state.
>

--
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering