Re: [PATCH] Add watchdog driver for w90p910

From: Wim Van Sebroeck
Date: Wed Aug 05 2009 - 06:31:41 EST


Hi Wan,

> > I have an additional question: which timeout values can you set? is it 0, 1, 2 and 3 seconds?
>
> The 0, 1, 2 and 3 is not seconds, rather than 'level' , it means my
> watchdog controller can only set four grades,
> When WTIS bit of REG_WTCR was set one value of the 0, 1, 2 and 3, the
> real time interval can be calculated via following formula .
>
> WTIS real time interval (formula)
> 0x00 ((2^ 14 ) * ((external crystal freq) / 256))seconds
> 0x01 ((2^ 16 ) * ((external crystal freq) / 256))seconds
> 0x02 ((2^ 18 ) * ((external crystal freq) / 256))seconds
> 0x03 ((2^ 20 ) * ((external crystal freq) / 256))seconds
>
> The external crystal freq is 15Mhz in w90p910 evaluation board. so I
> set the '0x00' as a default value, it means the real time interval is
> 0.28 second approximately.

Hmm, the watchdog API works in seconds.
A timer will need to be used like in similar watchdog drivers (like at91sam9_wdt.c, pcwd.c).

Kind regards,
Wim.

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