linux-kernel - Re: [PATCH 1/2] net: phy: Helper function for reading strapped configuration values

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Message-ID: <49448b00-e3fd-25df-580e-c02428f1bfe6@gmail.com>
Date:   Thu, 5 Apr 2018 09:00:13 -0700
From:   Florian Fainelli <f.fainelli@...il.com>
To:     esben.haabendal@...il.com, Andrew Lunn <andrew@...n.ch>,
        "open list:ETHERNET PHY LIBRARY" <netdev@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>
Cc:     Esben Haabendal <eha@...f.com>,
        Rasmus Villemoes <rasmus.villemoes@...vas.dk>
Subject: Re: [PATCH 1/2] net: phy: Helper function for reading strapped
 configuration values



On 04/05/2018 04:44 AM, esben.haabendal@...il.com wrote:
> From: Esben Haabendal <eha@...f.com>
> 
> Add a function for use in PHY driver probe functions, reading current
> autoneg, speed and duplex configuration from BMCR register.
> 
> Useful for PHY that supports hardware strapped configuration, enabling
> Linux to respect that configuration (i.e. strapped non-autoneg
> configuration).
> 
> Signed-off-by: Esben Haabendal <eha@...f.com>
> Cc: Rasmus Villemoes <rasmus.villemoes@...vas.dk>
> ---
>  drivers/net/phy/phy_device.c | 41 +++++++++++++++++++++++++++++++++++++++++
>  include/linux/phy.h          |  1 +
>  2 files changed, 42 insertions(+)
> 
> diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
> index 74664a6c0cdc..cc52ff2a2344 100644
> --- a/drivers/net/phy/phy_device.c
> +++ b/drivers/net/phy/phy_device.c
> @@ -1673,6 +1673,47 @@ int genphy_config_init(struct phy_device *phydev)
>  }
>  EXPORT_SYMBOL(genphy_config_init);
>  
> +/**
> + * genphy_read_config - read configuration from PHY
> + * @phydev: target phy_device struct
> + *
> + * Description: Reads MII_BMCR and sets phydev autoneg, speed and duplex
> + * accordingly.  For use in driver probe functions, to respect strapped
> + * configuration settings.
> + */
> +int genphy_read_config(struct phy_device *phydev)

This duplicates what already exists, in part at least within
genphy_read_status() can you find a way to use that?

I really wonder how this is going to work though because an user can
decide to force the PHY to have auto-negotiation disabled just like a
MAC could actually attempt to do that while connecting to the PHY...
more comments in patch 2.
-- 
Florian