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SubjectRe: [PATCH] net/macb: add support for resetting PHY using GPIO
On Wed, Dec 09, 2015 at 06:49:43PM +0100, Gregory CLEMENT wrote:
> With device tree it is no more possible to reset the PHY at board
> level. Furthermore, doing in the driver allow to power down the PHY when
> the network interface is no more used.
>
> The patch introduces a new optional property "phy-reset-gpio" inspired
> from the one use for the FEC.
>
> Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
> ---
> Documentation/devicetree/bindings/net/macb.txt | 3 +++
> drivers/net/ethernet/cadence/macb.c | 26 ++++++++++++++++++++++++++
> drivers/net/ethernet/cadence/macb.h | 1 +
> 3 files changed, 30 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/net/macb.txt b/Documentation/devicetree/bindings/net/macb.txt
> index b5d7976..546d34d 100644
> --- a/Documentation/devicetree/bindings/net/macb.txt
> +++ b/Documentation/devicetree/bindings/net/macb.txt
> @@ -19,6 +19,9 @@ Required properties:
> Optional elements: 'tx_clk'
> - clocks: Phandles to input clocks.
>
> +Optional properties:
> +- phy-reset-gpio : Should specify the gpio for phy reset

Hi Gregory

It is convention to use the plural here. So it should be phy-reset-gpios.

> +
> Examples:
>
> macb0: ethernet@fffc4000 {
> diff --git a/drivers/net/ethernet/cadence/macb.c b/drivers/net/ethernet/cadence/macb.c
> index 88c1e1a..e630c56 100644
> --- a/drivers/net/ethernet/cadence/macb.c
> +++ b/drivers/net/ethernet/cadence/macb.c
> @@ -30,6 +30,7 @@
> #include <linux/of_device.h>
> #include <linux/of_mdio.h>
> #include <linux/of_net.h>
> +#include <linux/of_gpio.h>
>
> #include "macb.h"
>
> @@ -2733,6 +2734,28 @@ static int at91ether_init(struct platform_device *pdev)
> return 0;
> }
>
> +#ifdef CONFIG_OF
> +static void macb_reset_phy(struct macb *bp, struct device_node *np, int state)
> +{
> + if (!np)
> + return;
> +
> + bp->reset_gpio = of_get_named_gpio(np, "phy-reset-gpio", 0);
> +
> + if (gpio_is_valid(bp->reset_gpio))
> + gpio_direction_output(bp->reset_gpio, state);

This does not handle the flags part of the GPIO descriptor in device
tree. i.e. ACTIVE_LOW or ACTIVE_HIGH. I think the FEC driver has the
same issue, and is not the best driver to copy. Using the gpiod API
will solve this issue.

Andrew


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