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Date:   Tue, 20 Apr 2021 14:51:32 -0500
From:   Rob Herring <robh@kernel.org>
To:     Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com>
Cc:     "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>, Felix Fietkau <nbd@nbd.name>,
        John Crispin <john@phrozen.org>,
        Sean Wang <sean.wang@mediatek.com>,
        Mark Lee <Mark-MC.Lee@mediatek.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Russell King <linux@armlinux.org.uk>, netdev@vger.kernel.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linux-mediatek@lists.infradead.org,
        =?iso-8859-1?Q?Ren=E9?= van Dorst <opensource@vdorst.com>
Subject: Re: [PATCH net-next v2 2/2] net: ethernet: mediatek: support custom
 GMAC label
Message-ID: <20210420195132.GA3686955@robh.at.kernel.org>
References: <20210419154659.44096-1-ilya.lipnitskiy@gmail.com>
 <20210419154659.44096-3-ilya.lipnitskiy@gmail.com>
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On Mon, Apr 19, 2021 at 08:46:59AM -0700, Ilya Lipnitskiy wrote:
> The MAC device name can now be set within DTS file instead of always
> being "ethX". This is helpful for DSA to clearly label the DSA master
> device and distinguish it from DSA slave ports.
> 
> For example, some devices, such as the Ubiquiti EdgeRouter X, may have
> ports labeled ethX. Labeling the master GMAC with a different prefix
> than DSA ports helps with clarity.
> 
> Suggested-by: Ren? van Dorst <opensource@vdorst.com>
> Signed-off-by: Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com>
> ---
>  drivers/net/ethernet/mediatek/mtk_eth_soc.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
> index 6b00c12c6c43..df3cda63a8c5 100644
> --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
> +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
> @@ -2845,6 +2845,7 @@ static const struct net_device_ops mtk_netdev_ops = {
>  
>  static int mtk_add_mac(struct mtk_eth *eth, struct device_node *np)
>  {
> +	const char *label = of_get_property(np, "label", NULL);
>  	const __be32 *_id = of_get_property(np, "reg", NULL);
>  	phy_interface_t phy_mode;
>  	struct phylink *phylink;
> @@ -2867,9 +2868,10 @@ static int mtk_add_mac(struct mtk_eth *eth, struct device_node *np)
>  		return -EINVAL;
>  	}
>  
> -	eth->netdev[id] = alloc_etherdev(sizeof(*mac));
> +	eth->netdev[id] = alloc_netdev(sizeof(*mac), label ? label : "eth%d",
> +				       NET_NAME_UNKNOWN, ether_setup);

'label' is generally supposed to correspond to the sticker for the 
device connector for a human to id. I can't really tell if that's the 
case here. I don't see how 'gmacX' vs. 'ethX' maps to DSA master vs. 
slave.

I don't think this should be handled within a specific driver either. If 
we're going to have a way to name things, then fix it in 
alloc_etherdev().

It can also be argued that device naming for userspace is a userspace 
(udev) problem. 

Rob