[U-Boot] [PATCH] net: phy: do not read configuration register on reset

[Michael Welling]

On Wed, Dec 09, 2015 at 11:21:25AM -0800, Stefan Agner wrote:
> When doing a software reset, the reset flag should be written without
> other bits set. Writing the current state will lead to restoring the
> state of the PHY (e.g. Powerdown), which is not what is expected from
> a software reset.
> 
> Signed-off-by: Stefan Agner <stefan at agner.ch>

Acked-by: Michael Welling <mwelling at ieee.org>

> ---
> This lead to the PHY staying powered down on a reboot when using a
> Micrel PHY and not using hardware reset...
> 
> It also aligns with the behavior of Linux:
> http://lxr.free-electrons.com/source/drivers/net/phy/phy_device.c#L1122
> 
> --
> Stefan
> 
>  drivers/net/phy/phy.c | 11 ++---------
>  1 file changed, 2 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
> index 51b5746..ef9f13b 100644
> --- a/drivers/net/phy/phy.c
> +++ b/drivers/net/phy/phy.c
> @@ -717,15 +717,7 @@ int phy_reset(struct phy_device *phydev)
>  	}
>  #endif
>  
> -	reg = phy_read(phydev, devad, MII_BMCR);
> -	if (reg < 0) {
> -		debug("PHY status read failed\n");
> -		return -1;
> -	}
> -
> -	reg |= BMCR_RESET;
> -
> -	if (phy_write(phydev, devad, MII_BMCR, reg) < 0) {
> +	if (phy_write(phydev, devad, MII_BMCR, BMCR_RESET) < 0) {
>  		debug("PHY reset failed\n");
>  		return -1;
>  	}
> @@ -738,6 +730,7 @@ int phy_reset(struct phy_device *phydev)
>  	 * auto-clearing).  This should happen within 0.5 seconds per the
>  	 * IEEE spec.
>  	 */
> +	reg = phy_read(phydev, devad, MII_BMCR);
>  	while ((reg & BMCR_RESET) && timeout--) {
>  		reg = phy_read(phydev, devad, MII_BMCR);
>  
> -- 
> 2.6.3
> 
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