On Thursday, September 06, 2018, Guenter Roeck wrote:
> > +static void rza_wdt_calc_timeout(struct rza_wdt *priv, int timeout)
> > +{
> > + int rate = clk_get_rate(priv->clk);
>
> clk_get_rate() returns unsigned long.
OK, I'll change it.
> > + u16 counter;
> > +
> > + if (priv->cks == CKS_4BIT) {
> > + counter = DIV_ROUND_UP((timeout * rate), 4194304) + 1;
>
> two spaces ?
Oh, did see that.
> Also, I am not sure how this prevents overflows. Was't the concern
> that timeout * rate might overflow an int ?
Actually, since 32 second is the max timeout for this WDT, I think at
first I'll check to see if "timeout" is greater than 32. If it is, there
is no reason to do any math. Then I won't have to worry about any
overflows from math.
if (timeout > 32)
counter = 256;
else
counter = DIV_ROUND_UP((timeout * rate), 4194304) + 1;
> Also, why still "+ 1" ? Wasn't DIV_ROUND_UP() supposed to take care
> of that ?
Ooops, I forgot to remove the "+ 1"
> > + if (counter > 255)
> > + counter = 0;
>
> This is difficult to understand.
As you suggested, I'll change this to:
if (counter > 256)
counter = 256;
Chris
