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From: Maxime Ripard <maxime@cerno.tech>
To: Samuel Holland <samuel@sholland.org>
Cc: Wim Van Sebroeck <wim@linux-watchdog.org>,
	Guenter Roeck <linux@roeck-us.net>,
	Rob Herring <robh+dt@kernel.org>, Chen-Yu Tsai <wens@csie.org>,
	Jernej Skrabec <jernej.skrabec@gmail.com>,
	devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-sunxi@lists.linux.dev, linux-watchdog@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/3] dt-bindings: watchdog: sunxi: Add compatible for R329
Date: Thu, 29 Jul 2021 14:18:19 +0200	[thread overview]
Message-ID: <20210729121819.oqryiww4mzow3kev@gilmour> (raw)
In-Reply-To: <20210726035143.53132-1-samuel@sholland.org>

Hi,

On Sun, Jul 25, 2021 at 10:51:41PM -0500, Samuel Holland wrote:
> On existing SoCs, the watchdog has a single clock input: HOSC (OSC24M)
> divided by 750.  However, starting with R329, LOSC (OSC32k) is added as
> an alternative clock source, with a bit to switch between them.
> 
> Since 24 MHz / 750 == 32 kHz, not 32.768 kHz, the hardware adjusts the
> cycle counts to keep the timeouts independent of the clock source. This
> keeps the programming interface backward-compatible.
> 
> R329 also adds two new registers, to allow software to immediately drive
> the SoC reset signal.
> 
> Signed-off-by: Samuel Holland <samuel@sholland.org>
> ---
>  .../watchdog/allwinner,sun4i-a10-wdt.yaml     | 30 ++++++++++++++++++-
>  1 file changed, 29 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/devicetree/bindings/watchdog/allwinner,sun4i-a10-wdt.yaml b/Documentation/devicetree/bindings/watchdog/allwinner,sun4i-a10-wdt.yaml
> index 9aa3c313c49f..853ceb1b7c0f 100644
> --- a/Documentation/devicetree/bindings/watchdog/allwinner,sun4i-a10-wdt.yaml
> +++ b/Documentation/devicetree/bindings/watchdog/allwinner,sun4i-a10-wdt.yaml
> @@ -24,6 +24,7 @@ properties:
>                - allwinner,sun50i-a100-wdt
>                - allwinner,sun50i-h6-wdt
>                - allwinner,sun50i-h616-wdt
> +              - allwinner,sun50i-r329-wdt
>            - const: allwinner,sun6i-a31-wdt
>        - items:
>            - const: allwinner,suniv-f1c100s-wdt
> @@ -33,7 +34,16 @@ properties:
>      maxItems: 1
>  
>    clocks:
> -    maxItems: 1
> +    minItems: 1
> +    maxItems: 2
> +
> +  clock-names:
> +    minItems: 1
> +    maxItems: 2
> +    items:
> +      enum:
> +        - hosc
> +        - losc

So I assume that the expectations are that hosc is first (or the only
valid choice with older SoCs), and losc second?

If so, we should make it clear using two const instead of an enum. Here
you state that on older SoCs we could use either the hosc or losc clocks
as source, which is incorrect.

I guess adding descriptions for clocks would be great too.

Maxime

      parent reply	other threads:[~2021-07-29 12:18 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-26  3:51 Samuel Holland
2021-07-26  3:51 ` [PATCH 2/3] dt-bindings: watchdog: sunxi: Add compatible for D1 Samuel Holland
2021-07-29  4:24   ` Guenter Roeck
2021-07-29 22:39     ` Rob Herring
2021-07-30  1:14       ` Guenter Roeck
2021-07-29 22:40   ` Rob Herring
2021-07-26  3:51 ` [PATCH 3/3] watchdog: sunxi_wdt: Add support " Samuel Holland
2021-07-29  4:11   ` Guenter Roeck
2021-07-29 12:18 ` Maxime Ripard [this message]

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