Hi Chris,
On Wed, Sep 5, 2018 at 7:40 PM Chris Brandt <chris.brandt@xxxxxxxxxxx> wrote:
> The RZ/A2 watchdog timer extends the clock source options in order to give
> you longer timeout options.
>
> Signed-off-by: Chris Brandt <chris.brandt@xxxxxxxxxxx>
Thanks for your patch!
> --- a/drivers/watchdog/rza_wdt.c
> +++ b/drivers/watchdog/rza_wdt.c
> @@ -38,8 +38,37 @@ struct rza_wdt {
> struct watchdog_device wdev;
> void __iomem *base;
> struct clk *clk;
> + bool ext_cks;
> + u8 count;
> + u8 cks;
> + u8 timeout;
> };
>
> +static void rza_wdt_calc_timeout(struct rza_wdt *priv, int timeout)
> +{
> + int rate = clk_get_rate(priv->clk);
> + u16 counter;
> +
> + if (priv->ext_cks) {
> + /* Add the 1 to deal with the inevitable fraction */
> + counter = ((timeout * rate) / 4194304) + 1;
"timeout * rate" may overflow
DIV_ROUND_UP()?
> + if (counter > 255)
> + counter = 0;
> +
> + priv->cks = 0xF;
> + priv->count = 256 - counter;
> + } else {
> + /* Start timer with longest timeout */
> + priv->cks = 7;
> + priv->count = 0;
> + }
> +
> + priv->timeout = timeout;
> +
> + pr_debug("%s: timeout set to %d (WTCNT=%d)\n", __func__,
%u for unsigned.
> + timeout, priv->count);
> +}
> @@ -150,20 +184,29 @@ static int rza_wdt_probe(struct platform_device *pdev)
> return -ENOENT;
> }
>
> - /* Assume slowest clock rate possible (CKS=7) */
> - rate /= 16384;
> + if (of_device_is_compatible(np, "renesas,r7s9210-wdt"))
> + priv->ext_cks = true;
That's not the proper way to support multiple devices.
Please add an entry for "renesas,r7s9210-wdt" to rza_wdt_of_match[].
"renesas,r7s9210-wdt" must be documented in the DT bindings.
I suggest storing cks in rza_wdt_of_match[].data, and retrieving it with
of_device_get_match_data() in your probe function, so you can use that to
differentiate, and get rid of the ext_cks flag.
BTW, is the RZ/A2 WDT compatible with the RZ/A1 WDT, i.e. does it work
with the unmodified driver? If not, "renesas,rza-wdt" must not be used as a
fallback.
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
