Re: [PATCH] dp83640: Ensure against premature access to PHY registers after reset

[Andrew Lunn]

On Fri, Apr 06, 2018 at 04:05:40PM +0200, Esben Haabendal wrote:
> From: Esben Haabendal <e...@deif.com>
> 
> Signed-off-by: Esben Haabendal <e...@deif.com>
> ---
>  drivers/net/phy/dp83640.c | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
> 
> diff --git a/drivers/net/phy/dp83640.c b/drivers/net/phy/dp83640.c
> index 654f42d00092..48403170096a 100644
> --- a/drivers/net/phy/dp83640.c
> +++ b/drivers/net/phy/dp83640.c
> @@ -1207,6 +1207,22 @@ static void dp83640_remove(struct phy_device *phydev)
>       kfree(dp83640);
>  }
>  
> +static int dp83640_soft_reset(struct phy_device *phydev)
> +{
> +     int ret;
> +
> +     ret = genphy_soft_reset(phydev);
> +     if (ret < 0)
> +             return ret;
> +
> +     /* From DP83640 datasheet: "Software driver code must wait 3 us
> +      * following a software reset before allowing further serial MII
> +      * operations with the DP83640." */
> +     udelay(3);

Hi Esben

The accuracy of udelay() is not guaranteed. So you probably want to be
a bit pessimistic, and use 10.

  Andrew