Re: [PATCH net] netsec: ignore 'phy-mode' device property on ACPI systems

From: Andrew Lunn <andrew@lunn.ch>
To: Ard Biesheuvel <ardb@kernel.org>
Cc: netdev@vger.kernel.org, Jassi Brar <jaswinder.singh@linaro.org>,
	Ilias Apalodimas <ilias.apalodimas@linaro.org>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Willy Liu <willy.liu@realtek.com>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Masahisa Kojima <masahisa.kojima@linaro.org>,
	Serge Semin <fancer.lancer@gmail.com>
Subject: Re: [PATCH net] netsec: ignore 'phy-mode' device property on ACPI systems
Date: Sun, 18 Oct 2020 19:52:18 +0200	[thread overview]
Message-ID: <20201018175218.GG456889@lunn.ch> (raw)
In-Reply-To: <20201018163625.2392-1-ardb@kernel.org>

> --- a/Documentation/devicetree/bindings/net/socionext-netsec.txt
> +++ b/Documentation/devicetree/bindings/net/socionext-netsec.txt
> @@ -30,7 +30,9 @@ Optional properties: (See ethernet.txt file in the same directory)
>  - max-frame-size: See ethernet.txt in the same directory.
>  
>  The MAC address will be determined using the optional properties
> -defined in ethernet.txt.
> +defined in ethernet.txt. The 'phy-mode' property is required, but may
> +be set to the empty string if the PHY configuration is programmed by
> +the firmware or set by hardware straps, and needs to be preserved.

In general, phy-mode is not mandatory. of_get_phy_mode() does the
right thing if it is not found, it sets &priv->phy_interface to
PHY_INTERFACE_MODE_NA, but returns -ENODEV. Also, it does not break
backwards compatibility to convert a mandatory property to
optional. So you could just do

	of_get_phy_mode(pdev->dev.of_node, &priv->phy_interface);

skip all the error checking, and document it as optional.

     Andrew