[PATCH RFC] Watchdog: sbsa_gwdt: Enhance timeout range

Guenter Roeck linux at roeck-us.net
Thu May 5 16:51:14 PDT 2016


On 05/05/2016 04:38 PM, Timur Tabi wrote:
> Guenter Roeck wrote:
>> A 32-bit counter is absolutely fine. Letting it run with a 400MHz clock
>> (or was it 200 MHz ?) is the problem. A resolution of 2.5ns for a watchdog
>> timer does not really make any sense.
>
> The 10 second limit is based on a 20MHz clock.
>
Not that a resolution of 50 ns makes sense either, but 4294967296 / 20971520 = 204,
and 20971520 * 10 = 209715200 = 0x0c800000. Where does the resolution get lost ?

Guenter




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