Hi Shimoda-san,
On Mon, Jun 3, 2019 at 11:31 AM Yoshihiro Shimoda
<yoshihiro.shimoda.uh@xxxxxxxxxxx> wrote:
> According to the hardware manual of R-Car Gen2 and Gen3,
> software should wait a few RLCK cycles as following:
> - Delay 2 cycles before setting watchdog counter.
> - Delay 3 cycles before disabling module clock.
>
> So, this patch adds such delays.
>
> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
Thanks for your patch!
> --- a/drivers/watchdog/renesas_wdt.c
> +++ b/drivers/watchdog/renesas_wdt.c
> @@ -70,6 +71,16 @@ static int rwdt_init_timeout(struct watchdog_device *wdev)
> return 0;
> }
>
> +static void rwdt_wait(struct rwdt_priv *priv, unsigned long cycles)
"unsigned int" should be sufficiently large.
> +{
> + unsigned long periods, delays;
> +
> + periods = DIV_ROUND_UP(priv->clk_rate, cycles);
Shouldn't the above be a division with rounding down (i.e. a plain C
division), instead of a division with rounding up?
> + delays = DIV_ROUND_UP(1000000UL, periods);
Given cycles is always a small number, accuracy can be improved, and one
division can be avoided, by calculation this as:
delays = DIV_ROUND_UP(cycles * 1000000 / priv->clk_rate);
> +
> + usleep_range(delays, 2 * delays);
> +}
The rest looks good to me, so
Reviewed-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
