linux-kernel - Re: [PATCH v2] net: fec: add post PHY reset delay DT property

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Date:   Wed, 31 May 2017 11:44:16 -0500
From:   Rob Herring <robh@...nel.org>
To:     Quentin Schulz <quentin.schulz@...e-electrons.com>
Cc:     fugang.duan@....com, mark.rutland@....com, netdev@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        thomas.petazzoni@...e-electrons.com
Subject: Re: [PATCH v2] net: fec: add post PHY reset delay DT property

On Tue, May 23, 2017 at 11:48:08AM +0200, Quentin Schulz wrote:
> Some PHY require to wait for a bit after the reset GPIO has been
> toggled. This adds support for the DT property `phy-reset-post-delay`
> which gives the delay in milliseconds to wait after reset.
> 
> If the DT property is not given, no delay is observed. Post reset delay
> greater than 1000ms are invalid.
> 
> Signed-off-by: Quentin Schulz <quentin.schulz@...e-electrons.com>
> ---
> 
> v2:
>   - return -EINVAL when phy-reset-post-delay is greater than 1000ms
>   instead of defaulting to 1ms,
>   - remove `default to 1ms` when phy-reset-post-delay > 1000Ms from DT
>   binding doc and commit log,
>   - move phy-reset-post-delay property reading before
>   devm_gpio_request_one(),
> 
>  Documentation/devicetree/bindings/net/fsl-fec.txt |  4 ++++
>  drivers/net/ethernet/freescale/fec_main.c         | 16 +++++++++++++++-
>  2 files changed, 19 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/devicetree/bindings/net/fsl-fec.txt b/Documentation/devicetree/bindings/net/fsl-fec.txt
> index a1e3693cca16..6f55bdd52f8a 100644
> --- a/Documentation/devicetree/bindings/net/fsl-fec.txt
> +++ b/Documentation/devicetree/bindings/net/fsl-fec.txt
> @@ -15,6 +15,10 @@ Optional properties:
>  - phy-reset-active-high : If present then the reset sequence using the GPIO
>    specified in the "phy-reset-gpios" property is reversed (H=reset state,
>    L=operation state).
> +- phy-reset-post-delay : Post reset delay in milliseconds. If present then

This needs unit suffix minimally. It should also have a vendor prefix or 
be made generic.

But really, this is a property of the phy and should be in the phy node 
as should phy-reset-gpios, phy-reset-active-high, phy-supply, etc.

> +  a delay of phy-reset-post-delay milliseconds will be observed after the
> +  phy-reset-gpios has been toggled. Can be omitted thus no delay is
> +  observed. Delay is in range of 1ms to 1000ms. Other delays are invalid.
>  - phy-supply : regulator that powers the Ethernet PHY.
>  - phy-handle : phandle to the PHY device connected to this device.
>  - fixed-link : Assume a fixed link. See fixed-link.txt in the same directory.