Re: [PATCH] of: mdio: Support fixed links in of_phy_get_and_connect()

[Andrew Lunn <andrew@lunn.ch>]

On Wed, Jul 11, 2018 at 07:45:11PM +0200, Linus Walleij wrote:
> By a simple extension of of_phy_get_and_connect() drivers
> that have a fixed link on e.g. RGMII can support also
> fixed links, so in addition to:
> 
> ethernet-port {
> 	phy-mode = "rgmii";
> 	phy-handle = <&foo>;
> };
> 
> This setup with a fixed-link node and no phy-handle will
> now also work just fine:
> 
> ethernet-port {
> 	phy-mode = "rgmii";
> 	fixed-link {
> 		speed = <1000>;
> 		full-duplex;
> 		pause;
> 	};
> };
> 
> This is very helpful for connecting random ethernet ports
> to e.g. DSA switches that typically reside on fixed links.
> 
> The phy-mode is still there as the fixes link in this case
> is still an RGMII link.
> 
> Tested on the Cortina Gemini driver with the Vitesse DSA
> router chip on a fixed 1Gbit link.
> 
> Suggested-by: Andrew Lunn <andrew@lunn.ch>
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

What probably make sense as a followup is add a
of_phy_disconnect_and_put(). When the module is unloaded, you leak a
fixed link, because of_phy_deregister_fixed_link() is not being
called. You also hold a reference to np which does not appear to be
released.

    Andrew