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

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@ni.com>
---
 drivers/net/ethernet/cadence/macb_main.c | 3 +++
 1 file changed, 3 insertions(+)

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@ni.com>
> ---
>  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

On Thu, Mar 08, 2018 at 06:32:47PM +0100, Andrew Lunn wrote:
> 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)
> > ...
> 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

Hi Andrew

That makes sense, I'll rework and resend. Thanks for the suggestion.

Brad