netdev - Re: [PATCH] net/macb: add support for resetting PHY using GPIO

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Message-ID: <20151211103322.GR8644@n2100.arm.linux.org.uk>
Date:	Fri, 11 Dec 2015 10:33:22 +0000
From:	Russell King - ARM Linux <linux@....linux.org.uk>
To:	Sascha Hauer <s.hauer@...gutronix.de>
Cc:	Gregory CLEMENT <gregory.clement@...e-electrons.com>,
	Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>,
	devicetree@...r.kernel.org, netdev@...r.kernel.org,
	Nicolas Ferre <nicolas.ferre@...el.com>,
	linux-kernel@...r.kernel.org,
	"David S. Miller" <davem@...emloft.net>,
	linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH] net/macb: add support for resetting PHY using GPIO

On Fri, Dec 11, 2015 at 11:21:30AM +0100, Sascha Hauer wrote:
> On Fri, Dec 11, 2015 at 10:40:22AM +0100, Gregory CLEMENT wrote:
> > So I see 2 options:
> > 
> > - leaving the phy-reset-gpios property in the ethernet node. Thanks to
> >   this we can use the gpiod functions, and it is still possible to use
> >   manage the power management.
> > 
> > - using a reset-gpios property inside the phy node. But then the only
> >   solution to get a reference on it, will be to use
> >   of_get_named_gpio. All the gpiod functions need a reference to the
> >   device that we won't have at this point. Also we will only be able to
> >   power up the reset, but we won't have any reference to it latter.
> 
> Have you seen fwnode_get_named_gpiod()? This seems to be the right
> function for the job.

Except:

1. You don't have a dev->fwnode pointer setup.
2. Using &dev->of_node->fwnode is really going underneath the covers.

I've pointed this problem out several times with the fwnode code, which
seems to be a half-baked and incomplete design when it comes to DT.

I'd suggest using of_get_named_gpio_flags() et.al. and converting the
resulting gpio number to a gpio descriptor - or trying to push DT and
fwnode people to initialise dev->fwnode so that a proper transition to
fwnode for DT can be made.

-- 
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