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Message-ID: <38f6708476e9beca4583ccc2a62e238a4981b735.camel@bootlin.com>
Subject: Re: [PATCH RESEND net] net: phy: xgmiitorgmii: Support generic PHY
 status read
From:   Paul Kocialkowski <paul.kocialkowski@bootlin.com>
To:     Florian Fainelli <f.fainelli@gmail.com>, netdev@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Cc:     Andrew Lunn <andrew@lunn.ch>,
        Heiner Kallweit <hkallweit1@gmail.com>,
        "David S . Miller" <davem@davemloft.net>,
        Michal Simek <michal.simek@xilinx.com>,
        Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Date:   Fri, 15 Feb 2019 19:34:28 +0100
In-Reply-To: <387ed483-b205-beda-319d-6f2b8ea55601@gmail.com>
References: <20190215163220.20041-1-paul.kocialkowski@bootlin.com>
         <387ed483-b205-beda-319d-6f2b8ea55601@gmail.com>
Organization: Bootlin
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Hi,

On Fri, 2019-02-15 at 09:38 -0800, Florian Fainelli wrote:
> On 2/15/19 8:32 AM, Paul Kocialkowski wrote:
> > Some PHY drivers like the generic one do not provide a read_status
> > callback on their own but rely on genphy_read_status being called
> > directly.
> > 
> > With the current code, this results in a NULL function pointer call.
> > Call genphy_read_status instead when there is no specific callback.
> > 
> > Fixes: f411a6160bd4 ("net: phy: Add gmiitorgmii converter support")
> > Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
> > ---
> > Added Fixes tag and net label for resend.
> 
> You would want to use phy_read_status() which encapsulates that check as
> well as checks that the phy_drv pointer is not NULL.

Well, this driver is a bit different and our priv->phy_drv != phydev-
>drv, so we can't use the helper directly. I should probably have
mentionned it in the commit message, sorry!

As I was mentionning to Andrew in the initial submission of this patch,
this driver is a bit unusual since it represents a GMII to RGMII
bridge, so it's not actually a PHY driver on its own -- it just sticks
itself in between the actual PHY and the MAC.

Cheers and thanks for the review,

Paul

> >  drivers/net/phy/xilinx_gmii2rgmii.c | 5 ++++-
> >  1 file changed, 4 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/net/phy/xilinx_gmii2rgmii.c b/drivers/net/phy/xilinx_gmii2rgmii.c
> > index 74a8782313cf..bd6084e315de 100644
> > --- a/drivers/net/phy/xilinx_gmii2rgmii.c
> > +++ b/drivers/net/phy/xilinx_gmii2rgmii.c
> > @@ -44,7 +44,10 @@ static int xgmiitorgmii_read_status(struct phy_device *phydev)
> >  	u16 val = 0;
> >  	int err;
> >  
> > -	err = priv->phy_drv->read_status(phydev);
> > +	if (priv->phy_drv->read_status)
> > +		err = priv->phy_drv->read_status(phydev);
> > +	else
> > +		err = genphy_read_status(phydev);
> >  	if (err < 0)
> >  		return err;
> >  
> > 
> 
> 
-- 
Paul Kocialkowski, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com