Subject: Re: [PATCH] netdev/phy: skip disabled mdio-mux nodes

From: David Daney <[email-masked]>
Date: Tue, 07 Aug 2012 09:59:25 -0700

On 08/07/2012 09:51 AM, Timur Tabi wrote:
> The mdio-mux driver scans all child mdio nodes, without regard to whether
> the node is actually used.  Some device trees include all possible
> mdio-mux nodes and rely on the boot loader to disable those that are not
> present, based on some run-time configuration.  Those nodes need to be
> skipped.
>
> Signed-off-by: Timur Tabi<[email-masked]>
> ---
>   drivers/net/phy/mdio-mux.c |    9 +++++++++
>   1 files changed, 9 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/net/phy/mdio-mux.c b/drivers/net/phy/mdio-mux.c
> index 5c12018..d0c231e 100644
> --- a/drivers/net/phy/mdio-mux.c
> +++ b/drivers/net/phy/mdio-mux.c
> @@ -135,6 +135,15 @@ int mdio_mux_init(struct device *dev,
>   	for_each_child_of_node(dev->of_node, child_bus_node) {
>   		u32 v;
>
> +		/*
> +		 * Some device trees include all possible mdio-mux nodes and
> +		 * rely on the boot loader to disable those that are not
> +		 * present, based on some run-time configuration.  Those nodes
> +		 * need to be skipped.
> +		 */
> +		if (!of_device_is_available(child_bus_node))
> +			continue;

Although this will get the job done, I don't think it is the cleanest 
approach.

Would it be better to create a new iterator 
(for_each_available_child_of_node perhaps) that skips the unavailable 
nodes?  This seems like a general problem that is not restricted to mdio 
multiplexers.

David Daney