netdev - Re: [PATCH] net: fec: Fix phy_device lookup for phy_reset_after_clk

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Date:   Wed, 7 Oct 2020 00:02:42 +0200
From:   Marek Vasut <marex@...x.de>
To:     Florian Fainelli <f.fainelli@...il.com>, netdev@...r.kernel.org
Cc:     Christoph Niedermaier <cniedermaier@...electronics.com>,
        "David S . Miller" <davem@...emloft.net>,
        NXP Linux Team <linux-imx@....com>,
        Richard Leitner <richard.leitner@...data.com>,
        Shawn Guo <shawnguo@...nel.org>
Subject: Re: [PATCH] net: fec: Fix phy_device lookup for
 phy_reset_after_clk_enable()

On 10/6/20 11:09 PM, Florian Fainelli wrote:
> 
> 
> On 10/6/2020 1:20 PM, Marek Vasut wrote:
>> The phy_reset_after_clk_enable() is always called with ndev->phydev,
>> however that pointer may be NULL even though the PHY device instance
>> already exists and is sufficient to perform the PHY reset.
>>
>> If the PHY still is not bound to the MAC, but there is OF PHY node
>> and a matching PHY device instance already, use the OF PHY node to
>> obtain the PHY device instance, and then use that PHY device instance
>> when triggering the PHY reset.
>>
>> Fixes: 1b0a83ac04e3 ("net: fec: add phy_reset_after_clk_enable()
>> support")
>> Signed-off-by: Marek Vasut <marex@...x.de>
>> Cc: Christoph Niedermaier <cniedermaier@...electronics.com>
>> Cc: David S. Miller <davem@...emloft.net>
>> Cc: NXP Linux Team <linux-imx@....com>
>> Cc: Richard Leitner <richard.leitner@...data.com>
>> Cc: Shawn Guo <shawnguo@...nel.org>
>> ---
>>   drivers/net/ethernet/freescale/fec_main.c | 22 ++++++++++++++++++++--
>>   1 file changed, 20 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/freescale/fec_main.c
>> b/drivers/net/ethernet/freescale/fec_main.c
>> index 2d5433301843..5a4b20941aeb 100644
>> --- a/drivers/net/ethernet/freescale/fec_main.c
>> +++ b/drivers/net/ethernet/freescale/fec_main.c
>> @@ -1912,6 +1912,24 @@ static int fec_enet_mdio_write(struct mii_bus
>> *bus, int mii_id, int regnum,
>>       return ret;
>>   }
>>   +static void fec_enet_phy_reset_after_clk_enable(struct net_device
>> *ndev)
>> +{
>> +    struct fec_enet_private *fep = netdev_priv(ndev);
>> +    struct phy_device *phy_dev = ndev->phydev;
>> +
>> +    /*
>> +     * If the PHY still is not bound to the MAC, but there is
>> +     * OF PHY node and a matching PHY device instance already,
>> +     * use the OF PHY node to obtain the PHY device instance,
>> +     * and then use that PHY device instance when triggering
>> +     * the PHY reset.
>> +     */
>> +    if (!phy_dev && fep->phy_node)
>> +        phy_dev = of_phy_find_device(fep->phy_node);
> 
> Don't you need to put the phy_dev reference at some point?

Probably, yes.

But first, does this approach and this patch even make sense ?
I mean, it fixes my problem, but is this right ?