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

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Date:	Sat, 14 May 2016 00:16:35 +0300
From:	Sergei Shtylyov <sergei.shtylyov@...entembedded.com>
To:	Andrew Lunn <andrew@...n.ch>
Cc:	Uwe Kleine-König <u.kleine-koenig@...gutronix.de>,
	grant.likely@...aro.org, robh+dt@...nel.org,
	devicetree@...r.kernel.org, f.fainelli@...il.com,
	netdev@...r.kernel.org, frowand.list@...il.com, pawel.moll@....com,
	mark.rutland@....com, ijc+devicetree@...lion.org.uk,
	galak@...eaurora.org, linux-kernel@...r.kernel.org,
	Linus Walleij <linus.walleij@...aro.org>
Subject: Re: [PATCH RFT 1/2] phylib: add device reset GPIO support

Hello.

On 05/13/2016 07:06 AM, Andrew Lunn wrote:

>>>> +	gpiod = fwnode_get_named_gpiod(&child->fwnode, "reset-gpios");
>>>> +	/* Deassert the reset signal */
>>>> +	if (!IS_ERR(gpiod))
>>>> +		gpiod_direction_output(gpiod, 0);
>>>
>>> This is wrong I think. You must only ignore -ENODEV, all other error
>>
>>    At least -ENOSYS should also be ignored (it's returned when
>> gpiolib is not configured), right? When does -ENODEV gets returned
>> (it's not easy to follow)?
>>
>>> codes should be passed to the caller.
>>
>>    The caller doesn't care anyway...
>
> It should do.

    Tell that to Florian. So far, everybody has been happy with 
of_mdiobus_register(). Until I had to touch this code. :-)

> What if fwnode_get_named_gpiod() returns -EPROBE_DEFER
> because the GPIO driver has not been loaded yet?

    Bad luck. :-)
    Seriously, I'll see what I can do but it's not a trivial case.

> 	Andrew

MBR, Sergei