Re: [v2,2/4] watchdog: at91sam9_wdt: update device tree doc

[Guenter Roeck <linux@roeck-us.net>]

On Fri, Jun 21, 2013 at 03:23:34PM -0000, Boris BREZILLON wrote:
> Add new at91sam9 watchdog properties to the documentation.
> 
> Signed-off-by: Boris BREZILLON <b.brezillon@overkiz.com>
> Acked-by: Grant Likely<grant.likely@linaro.org>
> 
> ---
> .../devicetree/bindings/watchdog/atmel-wdt.txt     |   30 ++++++++++++++++++--
>  1 file changed, 28 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/watchdog/atmel-wdt.txt b/Documentation/devicetree/bindings/watchdog/atmel-wdt.txt
> index fcdd48f..e043106 100644
> --- a/Documentation/devicetree/bindings/watchdog/atmel-wdt.txt
> +++ b/Documentation/devicetree/bindings/watchdog/atmel-wdt.txt
> @@ -9,11 +9,37 @@ Required properties:
>  
>  Optional properties:
>  - timeout-sec: contains the watchdog timeout in seconds.
> +- interrupts : Should contain WDT interrupt.
> +- atmel,max-heartbeat-sec : Should contain the maximum heartbeat value in
> +	seconds. This value should be less than 16. It is used to compute the
> +	WDV field.
> +- atmel,min-heartbeat-sec : Should contain the minimum heartbeat value in
> +	seconds. This value should be less than 4 times the max-heartbeat-sec
> +	value. It is used to compute the WDD field.

I am a bit at loss about "less than 4 times the max-heartbeat-sec value".
Why would a min-timeout larger than the max-timeout make sense under any
condition ? Do you mean to say that max-heartbeat should be at least four
times the value of min-heartbeat (or that min-heartbeat should be less or
equal to one-forth of max-heartbeat) ?

Guenter

> +- atmel,watchdog-type : Should be "hardware" or "software". Hardware watchdog
> +	use the at91 watchdog reset. Software watchdog use the watchdog
> +	interrupt to trigger a software reset.
> +- atmel,reset-type : Should be "proc" or "all".
> +	"all" : assert peripherals and processor reset signals
> +	"proc" : assert the processor reset signal
> +	This is valid only when using "hardware" watchdog.
> +- 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.
> +- atmel,dbg-halt : Should be present if you want to stop the watchdog when
> +	entering debug state.
>  
>  Example:
> -
>  	watchdog@fffffd40 {
>  		compatible = "atmel,at91sam9260-wdt";
>  		reg = <0xfffffd40 0x10>;
> -		timeout-sec = <10>;
> +		interrupts = <1 IRQ_TYPE_LEVEL_HIGH 7>;
> +		timeout-sec = <15>;
> +		atmel,watchdog-type = "hardware";
> +		atmel,reset-type = "all";
> +		atmel,dbg-halt;
> +		atmel,idle-halt;
> +		atmel,max-heartbeat-sec = <16>;
> +		atmel,min-heartbeat-sec = <0>;
> +		status = "okay";
>  	};