linux-kernel - Re: [PATCH] net: davinci_mdio: add GPIO reset logic

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Message-Id: <20170408.065545.2057882592764132853.davem@davemloft.net>
Date:   Sat, 08 Apr 2017 06:55:45 -0700 (PDT)
From:   David Miller <davem@...emloft.net>
To:     rogerq@...com
Cc:     tony@...mide.com, nsekhar@...com, jsarha@...com,
        netdev@...r.kernel.org, linux-omap@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] net: davinci_mdio: add GPIO reset logic

From: Roger Quadros <rogerq@...com>
Date: Wed, 5 Apr 2017 11:33:57 +0300

> Some boards [1] leave the PHYs at an invalid state
> during system power-up or reset thus causing unreliability
> issues with the PHY like not being detected by the mdio bus
> or link not functional. To work around these boards have
> a GPIO connected to the PHY's reset pin.
> 
> Implement GPIO reset handling for such cases.
> 
> [1] - am572x-idk, am571x-idk, a437x-idk.
> 
> Signed-off-by: Roger Quadros <rogerq@...com>
> Signed-off-by: Sekhar Nori <nsekhar@...com>

I have not seen a resolution in this discussion.

My understanding is that there are several cases (single MDIO bus whose
reset does a reset on all that MDIO bus's PHYs, etc.) and it's unclear
how to handle all such cases cleanly.