netdev - Re: [PATCH RFT 1/2] phylib: add device reset GPIO support

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Message-ID: <573232D4.6000006@gmail.com>
Date:	Tue, 10 May 2016 12:13:24 -0700
From:	Florian Fainelli <f.fainelli@...il.com>
To:	Sergei Shtylyov <sergei.shtylyov@...entembedded.com>,
	grant.likely@...aro.org, robh+dt@...nel.org,
	devicetree@...r.kernel.org, netdev@...r.kernel.org,
	frowand.list@...il.com, pawel.moll@....com, mark.rutland@....com,
	ijc+devicetree@...lion.org.uk, galak@...eaurora.org
Cc:	linux-kernel@...r.kernel.org
Subject: Re: [PATCH RFT 1/2] phylib: add device reset GPIO support

On 05/10/2016 12:11 PM, Sergei Shtylyov wrote:
> Hello.
> 
> On 05/10/2016 09:32 PM, Florian Fainelli wrote:
> 
>>> The PHY devices sometimes do have their reset signal (maybe even power
>>> supply?) tied to some GPIO and sometimes it also does happen that a boot
>>> loader does not leave it deasserted. So far this issue has been attacked
>>> from (as I believe) a wrong angle: by teaching the MAC driver to
>>> manipulate
>>> the GPIO in question; that solution, when applied to the device
>>> trees, led
>>> to adding the PHY reset GPIO properties to the MAC device node, with one
>>> exception: Cadence MACB driver which could handle the "reset-gpios" prop
>>> in a PHY device subnode. I believe that the correct approach is to teach
>>> the 'phylib' to get the MDIO device reset GPIO from the device tree node
>>> corresponding to this device -- which this patch is doing...
>>>
>>> Note that I had to modify the  AT803x PHY driver as it would stop
>>> working
>>> otherwise as it made use of the reset GPIO for its own purposes...
>>>
>>> Signed-off-by: Sergei Shtylyov <sergei.shtylyov@...entembedded.com>
>>
>> This looks good to me:
>>
>> Acked-by: Florian Fainelli <f.fainelli@...il.com>
> 
>    Thank you! I'll send v3 without [RFT] then.
> 
>> Can you follow up with changes in phy_{suspend,resume}
> 
>    I'm not sure what changes you mean -- powering down the PHYs?

Yes, powering down, conversely up the PHY. The whole point of putting
this in PHYLIB is to be able to perform things like that. We do not need
this right now, but it would be nice if we saw that materialize at some
point.
-- 
Florian