From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andrew Lunn <andrew@lunn.ch>
Subject: Re: PHY hardware reset
Date: Sun, 6 Mar 2016 01:22:21 +0100
Message-ID: <20160306002221.GC1976@lunn.ch>
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Cc: Florian Fainelli <f.fainelli@gmail.com>, netdev@vger.kernel.org
To: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
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On Sun, Mar 06, 2016 at 01:09:40AM +0300, Sergei Shtylyov wrote:
> Hello.
> 
>    I have a need to de-assert the active-low PHY hardware reset
> signal (mapped to a GPIO) before the MDIO bus scansince it's left
> asserted by the bootloader (U-Boot).

Hi Sergei

There is a thread about power sequencing for USB devices going on at
the moment. You have a very similar issue. The solution should be
generic enough to apply to MDIO busses as well as USB busses.

Search for:

[PATCH 1/3] usb: core: add power sequence for USB devices

       Andrew