netdev - Re: [PATCH] phy: add support for a reset-gpio specification

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Date:	Fri, 13 May 2016 00:41:47 +0300
From:	Sergei Shtylyov <sergei.shtylyov@...entembedded.com>
To:	Uwe Kleine-König <u.kleine-koenig@...gutronix.de>,
	netdev@...r.kernel.org, devicetree@...r.kernel.org,
	Florian Fainelli <f.fainelli@...il.com>
Cc:	kernel@...gutronix.de, "Andrew F . Davis" <afd@...com>,
	Nishanth Menon <nm@...com>
Subject: Re: [PATCH] phy: add support for a reset-gpio specification

On 05/12/2016 01:00 PM, Uwe Kleine-König wrote:

> The framework only asserts (for now) that the reset gpio is not active.
>
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
> ---
>  Documentation/devicetree/bindings/net/phy.txt | 3 +++
>  drivers/net/phy/phy_device.c                  | 8 ++++++++
>  2 files changed, 11 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/net/phy.txt b/Documentation/devicetree/bindings/net/phy.txt
> index bc1c3c8bf8fa..c00a9a894547 100644
> --- a/Documentation/devicetree/bindings/net/phy.txt
> +++ b/Documentation/devicetree/bindings/net/phy.txt
> @@ -35,6 +35,8 @@ Optional Properties:
>  - broken-turn-around: If set, indicates the PHY device does not correctly
>    release the turn around line low at the end of a MDIO transaction.
>
> +- reset-gpios: Reference to a GPIO used to reset the phy.
> +
>  Example:
>
>  ethernet-phy@0 {
> @@ -42,4 +44,5 @@ ethernet-phy@0 {
>  	interrupt-parent = <40000>;
>  	interrupts = <35 1>;
>  	reg = <0>;
> +	reset-gpios = <&gpio1 17 GPIO_ACTIVE_LOW>;
 >  };

    OK, the example has PHY ID specified in the "compatible" prop. It's a 
vital detail, you should mention it somewhere...

> diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
> index e551f3a89cfd..7d666ab47271 100644
> --- a/drivers/net/phy/phy_device.c
> +++ b/drivers/net/phy/phy_device.c
[...]
> @@ -1569,9 +1570,16 @@ static int phy_probe(struct device *dev)
>  	struct device_driver *drv = phydev->mdio.dev.driver;
>  	struct phy_driver *phydrv = to_phy_driver(drv);
>  	int err = 0;
> +	struct gpio_descs *reset_gpios;
>
>  	phydev->drv = phydrv;
>
> +	/* take phy out of reset */
> +	reset_gpios = devm_gpiod_get_array_optional(dev, "reset",
> +						    GPIOD_OUT_LOW);
> +	if (IS_ERR(reset_gpios))
> +		return PTR_ERR(reset_gpios);
> +

    It would have been logical to assert back the reset GPIO in phy_remove(), 
no? Also, you'd need to store the GPIO permanently somewhere...

MBR, Sergei