netdev - Re: [PATCH net-next 3/3] net: phy: mdio-gpio: Handle phy_ignore_ta

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Date:	Wed, 13 May 2015 13:17:06 +0200
From:	Bert Vermeulen <bert@...t.com>
To:	Florian Fainelli <f.fainelli@...il.com>, netdev@...r.kernel.org
CC:	davem@...emloft.net, jogo@...nwrt.org
Subject: Re: [PATCH net-next 3/3] net: phy: mdio-gpio: Handle phy_ignore_ta_mask

On 05/12/2015 07:33 PM, Florian Fainelli wrote:
> Update mdiobb_read() to read whether the PHY has a broken turn-around,
> and if it does, ignore it to make the read succeeed.
> 
> Signed-off-by: Florian Fainelli <f.fainelli@...il.com>
> ---
>  drivers/net/phy/mdio-bitbang.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/phy/mdio-bitbang.c b/drivers/net/phy/mdio-bitbang.c
> index daec9b05d168..61a543c788cc 100644
> --- a/drivers/net/phy/mdio-bitbang.c
> +++ b/drivers/net/phy/mdio-bitbang.c
> @@ -165,8 +165,11 @@ static int mdiobb_read(struct mii_bus *bus, int phy, int reg)
>  
>  	ctrl->ops->set_mdio_dir(ctrl, 0);
>  
> -	/* check the turnaround bit: the PHY should be driving it to zero */
> -	if (mdiobb_get_bit(ctrl) != 0) {
> +	/* check the turnaround bit: the PHY should be driving it to zero, if this
> +	 * PHY is listed in phy_ignore_ta_mask as having broken TA, skip that
> +	 */
> +	if (mdiobb_get_bit(ctrl) != 0 &&
> +	    !(bus->phy_ignore_ta_mask & (1 << phy))) {
>  		/* PHY didn't drive TA low -- flush any bits it
>  		 * may be trying to send.
>  		 */
> 

Note that this means a PHY with a broken TA is marked with a 1 bit here,
which is exactly the reverse of the mii_bus.phy_mask field -- where a 0 bit
means ignore the PHY when probing.

For the record I think it's the phy_mask usage that doesn't make sense here,
but the inconsistency is unfortunate.


-- 
Bert Vermeulen        bert@...t.com          email/xmpp
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