Re: [1/2] net: macb: Add phy-handle DT support

From: Andrew Lunn
Date: Thu Mar 08 2018 - 12:33:06 EST


On Wed, Mar 07, 2018 at 04:42:56PM -0600, Brad Mouring wrote:
> This optional binding (as described in the ethernet DT bindings doc)
> directs the netdev to the phydev to use. This is useful for a phy
> chip that has >1 phy in it, and two netdevs are using the same phy
> chip (i.e. the second mac's phy lives on the first mac's MDIO bus)
>
> The devicetree snippet would look something like this:
>
> ethernet@feedf00d {
> ...
> phy-handle = <&phy0> // the first netdev is physically wired to phy0
> ...
> phy0: phy@0 {
> ...
> reg = <0x0> // MDIO address 0
> ...
> }
> phy1: phy@1 {
> ...
> reg = <0x1> // MDIO address 1
> ...
> }
> ...
> }
>
> ethernet@deadbeef {
> ...
> phy-handle = <&phy1> // tells the driver to use phy1 on the
> // first mac's mdio bus (it's wired thusly)
> ...
> }
>
> The work done to add the phy_node in the first place (dacdbb4dfc1a1:
> "net: macb: add fixed-link node support") will consume the
> device_node (if found).
>
> Signed-off-by: Brad Mouring <brad.mouring@xxxxxx>
> ---
> drivers/net/ethernet/cadence/macb_main.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
> index e84afcf1ecb5..cc5b9e6e3526 100644
> --- a/drivers/net/ethernet/cadence/macb_main.c
> +++ b/drivers/net/ethernet/cadence/macb_main.c
> @@ -567,6 +567,9 @@ static int macb_mii_init(struct macb *bp)
>
> err = mdiobus_register(bp->mii_bus);
> } else {
> + /* attempt to find a phy-handle */
> + bp->phy_node = of_parse_phandle(np, "phy-handle", 0);
> +
> /* try dt phy registration */
> err = of_mdiobus_register(bp->mii_bus, np);
>

Hi Brad

I think it is more logical to do this in macb_mii_probe().

I would probably also move the fixed_link code from macb_mii_init() to
macb_mii_probe(). I would probably also move the fallback to standard
phy registration. Make macb_mii_init() about registering the MDIO bus,
and macb_mii_probe() about probing the MDIO bus to find the PHY to
use. At the moment, it is all rather mixed up.

Andrew