Subject: Re: [net-next: PATCH v3 2/6] net: mdiobus: Introduce fwnode_mdbiobus_register()

From: Andrew Lunn <[email-masked]>
Date: Wed, 23 Jun 2021 22:22:44 +0200

On Mon, Jun 21, 2021 at 07:30:24PM +0200, Marcin Wojtas wrote:
> This patch introduces a new helper function that
> wraps acpi_/of_ mdiobus_register() and allows its
> usage via common fwnode_ interface.
> 
> Fall back to raw mdiobus_register() in case CONFIG_FWNODE_MDIO
> is not enabled, in order to satisfy compatibility
> in all future user drivers.
> 
> Signed-off-by: Marcin Wojtas <[email-masked]>
> ---
>  include/linux/fwnode_mdio.h    | 12 +++++++++++
>  drivers/net/mdio/fwnode_mdio.c | 22 ++++++++++++++++++++
>  2 files changed, 34 insertions(+)
> 
> diff --git a/include/linux/fwnode_mdio.h b/include/linux/fwnode_mdio.h
> index faf603c48c86..13d4ae8fee0a 100644
> --- a/include/linux/fwnode_mdio.h
> +++ b/include/linux/fwnode_mdio.h
> @@ -16,6 +16,7 @@ int fwnode_mdiobus_phy_device_register(struct mii_bus *mdio,
>  int fwnode_mdiobus_register_phy(struct mii_bus *bus,
>  				struct fwnode_handle *child, u32 addr);
>  
> +int fwnode_mdiobus_register(struct mii_bus *bus, struct fwnode_handle *fwnode);
>  #else /* CONFIG_FWNODE_MDIO */
>  int fwnode_mdiobus_phy_device_register(struct mii_bus *mdio,
>  				       struct phy_device *phy,
> @@ -30,6 +31,17 @@ static inline int fwnode_mdiobus_register_phy(struct mii_bus *bus,
>  {
>  	return -EINVAL;
>  }
> +
> +static inline int fwnode_mdiobus_register(struct mii_bus *bus,
> +					  struct fwnode_handle *fwnode)
> +{
> +	/*
> +	 * Fall back to mdiobus_register() function to register a bus.
> +	 * This way, we don't have to keep compat bits around in drivers.
> +	 */
> +
> +	return mdiobus_register(mdio);
> +}
>  #endif

I looked at this some more, and in the end i decided it was O.K.

> +/**
> + * fwnode_mdiobus_register - bring up all the PHYs on a given MDIO bus and
> + *	attach them to it.
> + * @bus: Target MDIO bus.
> + * @fwnode: Pointer to fwnode of the MDIO controller.
> + *
> + * Return values are determined accordingly to acpi_/of_ mdiobus_register()
> + * operation.
> + */
> +int fwnode_mdiobus_register(struct mii_bus *bus, struct fwnode_handle *fwnode)
> +{
> +	if (is_acpi_node(fwnode))
> +		return acpi_mdiobus_register(bus, fwnode);
> +	else if (is_of_node(fwnode))
> +		return of_mdiobus_register(bus, to_of_node(fwnode));
> +	else
> +		return -EINVAL;

I wounder if here you should call mdiobus_register(mdio), rather than
-EINVAL?

I don't have a strong opinion.

Reviewed-by: Andrew Lunn <[email-masked]>

    Andrew