netdev - Re: [PATCH] net: phy: at803x: don't depend on GPIOLIB

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Date:	Sat, 19 Mar 2016 10:01:44 +0000
From:	Måns Rullgård <mans@...sr.com>
To:	Mason <slash.tmp@...e.fr>
Cc:	Uwe Kleine-Koenig <u.kleine-koenig@...gutronix.de>,
	Sebastian Frias <sf84@...oste.net>,
	Daniel Mack <daniel@...que.org>,
	"David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org,
	lkml <linux-kernel@...r.kernel.org>,
	Florian Fainelli <f.fainelli@...il.com>,
	Fabio Estevam <festevam@...il.com>,
	Martin Blumenstingl <martin.blumenstingl@...il.com>,
	Linus Walleij <linus.walleij@...aro.org>
Subject: Re: [PATCH] net: phy: at803x: don't depend on GPIOLIB

Mason <slash.tmp@...e.fr> writes:

> On 18/03/2016 21:11, Uwe Kleine-König wrote:
>
>> Hello,
>> 
>> On Fri, Mar 18, 2016 at 08:31:20PM +0100, Mason wrote:
>>
>>> On 18/03/2016 20:12, Uwe Kleine-König wrote:
>>>
>>>> On Fri, Mar 18, 2016 at 04:56:21PM +0100, Sebastian Frias wrote:
>>>>
>>>>> What would you think of making at803x_link_change_notify() print a
>>>>> message every time it should do a reset but does not has a way to do it?
>>>>
>>>> Then this question is obsolete because the device doesn't probe.
>>>
>>> I don't understand this statement.
>>>
>>> What does it mean for a question to be obsolete?
>> 
>> If the driver doesn't probe because it cannot control the reset line,
>> you don't need to think about how it should behave in
>> at803x_link_change_notify without control of the reset line, because
>> this code isn't reached then.
>
> If I understand correctly, it is possible to soft-reset the PHY
> by writing to a specific register. The GPIO pin is useful only to
> force a hardware-reset when the PHY is wedged by some random event.

Yes, and some variants of this phy are broken and require a hard reset
in certain situations.  At least that's what the comment in the code
says.

-- 
Måns Rullgård