linux-kernel - Re: [PATCH v2] net: fec: Add "phy-reset-active-low" property to DT

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Message-ID: <56CA110B.6020107@cogentembedded.com>
Date:	Sun, 21 Feb 2016 22:33:31 +0300
From:	Sergei Shtylyov <sergei.shtylyov@...entembedded.com>
To:	Bernhard Walle <bernhard@...lle.de>, fabio.estevam@...escale.com
Cc:	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
	netdev@...r.kernel.org
Subject: Re: [PATCH v2] net: fec: Add "phy-reset-active-low" property to DT

Hello.

On 02/09/2016 11:01 PM, Bernhard Walle wrote:

> We need that for a custom hardware that needs the reverse reset
> sequence.
>
> Signed-off-by: Bernhard Walle <bernhard@...lle.de>
> ---
> Changes compared to v1:
>   - Add documentation to 'phy-reset-gpios' that flags are ignored
>     as suggested by Andrew Lunn.
>
>   Documentation/devicetree/bindings/net/fsl-fec.txt | 7 ++++++-
>   drivers/net/ethernet/freescale/fec_main.c         | 8 ++++++--
>   2 files changed, 12 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/net/fsl-fec.txt b/Documentation/devicetree/bindings/net/fsl-fec.txt
> index a9eb611..0caa429 100644
> --- a/Documentation/devicetree/bindings/net/fsl-fec.txt
> +++ b/Documentation/devicetree/bindings/net/fsl-fec.txt
> @@ -7,11 +7,16 @@ Required properties:
>   - phy-mode : See ethernet.txt file in the same directory
>
>   Optional properties:
> -- phy-reset-gpios : Should specify the gpio for phy reset
> +- phy-reset-gpios : Should specify the gpio for phy reset. Additional
> +  flags are ignored, see the non-standard 'phy-reset-active-low' property
> +  instead.
>   - phy-reset-duration : Reset duration in milliseconds.  Should present
>     only if property "phy-reset-gpios" is available.  Missing the property
>     will have the duration be 1 millisecond.  Numbers greater than 1000 are
>     invalid and 1 millisecond will be used instead.
> +- phy-reset-active-low : If present then the reset sequence using the GPIO
> +  specified in the "phy-reset-gpios" property is reversed (H=reset state,
> +  L=operation state).

    It would be active high reset, no?

>   - 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.
> diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
> index 41c81f6..98caf87 100644
> --- a/drivers/net/ethernet/freescale/fec_main.c
> +++ b/drivers/net/ethernet/freescale/fec_main.c
> @@ -3229,6 +3229,7 @@ static int fec_enet_init(struct net_device *ndev)
>   static void fec_reset_phy(struct platform_device *pdev)
>   {
>   	int err, phy_reset;
> +	bool active_low = false;
>   	int msec = 1;
>   	struct device_node *np = pdev->dev.of_node;
>
> @@ -3244,14 +3245,17 @@ static void fec_reset_phy(struct platform_device *pdev)
>   	if (!gpio_is_valid(phy_reset))
>   		return;
>
> +	active_low = of_property_read_bool(np, "phy-reset-active-low");
> +
>   	err = devm_gpio_request_one(&pdev->dev, phy_reset,
> -				    GPIOF_OUT_INIT_LOW, "phy-reset");
> +			active_low ? GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW,
> +			"phy-reset");
>   	if (err) {
>   		dev_err(&pdev->dev, "failed to get phy-reset-gpios: %d\n", err);
>   		return;
>   	}
>   	msleep(msec);
> -	gpio_set_value_cansleep(phy_reset, 1);
> +	gpio_set_value_cansleep(phy_reset, !active_low);

    I believe the above expressions should be inverted.

MBR, Sergei