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From:   Chen-Yu Tsai <wens@csie.org>
Date:   Wed, 14 Aug 2019 12:38:51 +0800
Message-ID: <CAGb2v66mp-=T=-zDYMf6Qw-vaiR3OB5Xhxie39jeKWS+Kvmecw@mail.gmail.com>
Subject: Re: [PATCH 4/5] ARM: dts: sun8i: a83t: Remove the watchdog clock
To:     Maxime Ripard <mripard@kernel.org>
Cc:     Guenter Roeck <linux@roeck-us.net>,
        Wim Van Sebroeck <wim@linux-watchdog.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Rob Herring <robh+dt@kernel.org>,
        Frank Rowand <frowand.list@gmail.com>,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
        devicetree <devicetree@vger.kernel.org>,
        Maxime Ripard <maxime.ripard@bootlin.com>
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On Tue, Aug 13, 2019 at 8:47 PM Maxime Ripard <mripard@kernel.org> wrote:
>
> From: Maxime Ripard <maxime.ripard@bootlin.com>
>
> The watchdog binding doesn't define a clock, and it indeed looks like
> there's no explicit clock feeding it.

The diagram on page 133 of the manual shows OSC24M / 750 feeding the watchdog.

Other manuals, such as the A10 one, mention:

    Watchdog clock source is OSC24M. if the OSC24M is turned off, the watchdog
    will not work.

So in fact it does use a clock signal. It's just that we've been lazy, since
the clock rate is fixed and is always on.

ChenYu

> Let's remove it from our DT.
>
> Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
> ---
>  arch/arm/boot/dts/sun8i-a83t.dtsi | 1 -
>  1 file changed, 1 deletion(-)
>
> diff --git a/arch/arm/boot/dts/sun8i-a83t.dtsi b/arch/arm/boot/dts/sun8i-a83t.dtsi
> index 523be6611c50..15f8c80f69a5 100644
> --- a/arch/arm/boot/dts/sun8i-a83t.dtsi
> +++ b/arch/arm/boot/dts/sun8i-a83t.dtsi
> @@ -817,7 +817,6 @@
>                         compatible = "allwinner,sun6i-a31-wdt";
>                         reg = <0x01c20ca0 0x20>;
>                         interrupts = <GIC_SPI 25 IRQ_TYPE_LEVEL_HIGH>;
> -                       clocks = <&osc24M>;
>                 };
>
>                 spdif: spdif@1c21000 {
> --
> 2.21.0
>