Re: [PATCH] ARM: i.MX: edmqmx6: free phy-reset gpio pin

[Sascha Hauer <s.hauer@pengutronix.de>]

Hi Silvio,

On Wed, Sep 17, 2014 at 08:33:00AM +0200, Silvio Fricke wrote:
> Since 93a6c6a808("dts: update to v3.17-rc2") we have a correct gpio
> configuration. This results in a double gpio request what receipted in a
> error message like this one:
> 
> 	gpiolib: _gpio_request: gpio-25 (phy-reset) status -16
> 
> Now with this patch the problem is gone.
> 
> Signed-off-by: Silvio Fricke <silvio.fricke@gmail.com>
> ---
>  arch/arm/boards/datamodul-edm-qmx6/board.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm/boards/datamodul-edm-qmx6/board.c b/arch/arm/boards/datamodul-edm-qmx6/board.c
> index e388e28..25f45df 100644
> --- a/arch/arm/boards/datamodul-edm-qmx6/board.c
> +++ b/arch/arm/boards/datamodul-edm-qmx6/board.c
> @@ -49,6 +49,7 @@
>  #define RQ7_GPIO_ENET_MODE2	IMX_GPIO_NR(6, 28)
>  #define RQ7_GPIO_ENET_MODE3	IMX_GPIO_NR(6, 29)
>  #define RQ7_GPIO_ENET_EN_CLK125	IMX_GPIO_NR(6, 24)
> +#define RQ7_GPIO_ENET_RESET     IMX_GPIO_NR(1, 25)
>  
>  static iomux_v3_cfg_t realq7_pads_gpio[] = {
>  	MX6Q_PAD_RGMII_RXC__GPIO_6_30,
> @@ -57,6 +58,7 @@ static iomux_v3_cfg_t realq7_pads_gpio[] = {
>  	MX6Q_PAD_RGMII_RD2__GPIO_6_28,
>  	MX6Q_PAD_RGMII_RD3__GPIO_6_29,
>  	MX6Q_PAD_RGMII_RX_CTL__GPIO_6_24,
> +	MX6Q_PAD_ENET_CRS_DV__GPIO_1_25,
>  };
>  
>  static int ksz9031rn_phy_fixup(struct phy_device *dev)
> @@ -85,12 +87,14 @@ static int realq7_enet_init(void)
>  	gpio_direction_output(RQ7_GPIO_ENET_MODE3, 1);
>  	gpio_direction_output(RQ7_GPIO_ENET_EN_CLK125, 1);
>  
> -	gpio_direction_output(25, 0);
> +	gpio_direction_output(RQ7_GPIO_ENET_RESET, 0);
>  	mdelay(50);
>  
> -	gpio_direction_output(25, 1);
> +	gpio_direction_output(RQ7_GPIO_ENET_RESET, 1);
>  	mdelay(50);
>  
> +	gpio_free(RQ7_GPIO_ENET_RESET);
> +
>  	phy_register_fixup_for_uid(PHY_ID_KSZ9031, MICREL_PHY_ID_MASK,
>  					   ksz9031rn_phy_fixup);

I'm not sure this fully works as expected. Here the code configures the
ethernet pins as gpios with defined output states and resets the phy
afterwards. This makes sure the phy bootstrap pins are configured
correctly during phy reset.
Now the driver core sets up the ethernet pins to their functional mode
and the fec driver resets the phy again with some undefined states.
IMO this phy-reset-gpio property really stinks. Not that it's in the
wrong place (should be in a phy node, not the ethernet node), it also
destroys all careful phy setup done earlier.

I don't know a good way out of this situation, but it seems we should
create a way to reset the phy either properly or not at all.

Sascha

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