netdev - Re: [PATCH RESEND net-next v2 1/8] dt-bindings: net: dwmac-sun8i: Clean up clock delay chain descriptions

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Message-ID: <CAGb2v66nqWnioS1pwfWFtMZFZSWvf4SwXr_ExnnGvYsK9RU_LA@mail.gmail.com>
Date:   Sun, 13 May 2018 12:53:27 -0700
From:   Chen-Yu Tsai <wens@...e.org>
To:     Andrew Lunn <andrew@...n.ch>
Cc:     Giuseppe Cavallaro <peppe.cavallaro@...com>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        devicetree <devicetree@...r.kernel.org>,
        netdev <netdev@...r.kernel.org>,
        Corentin Labbe <clabbe.montjoie@...il.com>,
        Icenowy Zheng <icenowy@...c.io>,
        Maxime Ripard <maxime.ripard@...tlin.com>,
        Rob Herring <robh+dt@...nel.org>
Subject: Re: [PATCH RESEND net-next v2 1/8] dt-bindings: net: dwmac-sun8i:
 Clean up clock delay chain descriptions

On Sun, May 13, 2018 at 12:49 PM, Andrew Lunn <andrew@...n.ch> wrote:
> On Mon, May 14, 2018 at 03:14:18AM +0800, Chen-Yu Tsai wrote:
>> The clock delay chains found in the glue layer for dwmac-sun8i are only
>> used with RGMII PHYs. They are not intended for non-RGMII PHYs, such as
>> MII external PHYs or the internal PHY. Also, a recent SoC has a smaller
>> range of possible values for the delay chain.
>>
>> This patch reformats the delay chain section of the device tree binding
>> to make it clear that the delay chains only apply to RGMII PHYs, and
>> make it easier to add the R40-specific bits later.
>>
>> Signed-off-by: Chen-Yu Tsai <wens@...e.org>
>> Reviewed-by: Rob Herring <robh@...nel.org>
>> Acked-by: Maxime Ripard <maxime.ripard@...tlin.com>
>> ---
>>  Documentation/devicetree/bindings/net/dwmac-sun8i.txt | 11 +++++++----
>>  1 file changed, 7 insertions(+), 4 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/net/dwmac-sun8i.txt b/Documentation/devicetree/bindings/net/dwmac-sun8i.txt
>> index 3d6d5fa0c4d5..e04ce75e24a3 100644
>> --- a/Documentation/devicetree/bindings/net/dwmac-sun8i.txt
>> +++ b/Documentation/devicetree/bindings/net/dwmac-sun8i.txt
>> @@ -28,10 +28,13 @@ Required properties:
>>    - allwinner,sun8i-a83t-system-controller
>>
>>  Optional properties:
>> -- allwinner,tx-delay-ps: TX clock delay chain value in ps. Range value is 0-700. Default is 0)
>> -- allwinner,rx-delay-ps: RX clock delay chain value in ps. Range value is 0-3100. Default is 0)
>> -Both delay properties need to be a multiple of 100. They control the delay for
>> -external PHY.
>> +- allwinner,tx-delay-ps: TX clock delay chain value in ps.
>> +                      Range is 0-700. Default is 0.
>> +- allwinner,rx-delay-ps: RX clock delay chain value in ps.
>> +                      Range is 0-3100. Default is 0.
>> +Both delay properties need to be a multiple of 100. They control the
>> +clock delay for external RGMII PHY. They do not apply to the internal
>> +PHY or external non-RGMII PHYs.
>
> Hi Chen-Yu
>
> Are these delays the MAC applies? Not the PHY. It would be good to
> make it clear here these are MAC imposed delays.

Yes these are applied on the MAC side. Being described in the device
tree bindings for the MAC, I thought this was implied to be the case?
Are there known exceptions?

Thanks
ChenYu