Re: [PATCH v5 05/10] dt-bindings: net: dwmac-sun8i: update documentation about integrated PHY

From: Corentin Labbe
Date: Thu Sep 14 2017 - 14:53:17 EST

On Wed, Sep 13, 2017 at 01:20:04PM -0500, Rob Herring wrote:
> On Fri, Sep 08, 2017 at 09:43:25AM +0200, Corentin Labbe wrote:
> > On Fri, Sep 08, 2017 at 09:25:38AM +0200, Maxime Ripard wrote:
> > > On Fri, Sep 08, 2017 at 09:11:51AM +0200, Corentin Labbe wrote:
> > > > This patch add documentation about the MDIO switch used on sun8i-h3-emac
> > > > for integrated PHY.
> > > >
> > > > Signed-off-by: Corentin Labbe <clabbe.montjoie@xxxxxxxxx>
> > > > ---
> > > > .../devicetree/bindings/net/dwmac-sun8i.txt | 127 +++++++++++++++++++--
> > > > 1 file changed, 120 insertions(+), 7 deletions(-)
> > > >
> > > > diff --git a/Documentation/devicetree/bindings/net/dwmac-sun8i.txt b/Documentation/devicetree/bindings/net/dwmac-sun8i.txt
> > > > index 725f3b187886..3fa0e54825ea 100644
> > > > --- a/Documentation/devicetree/bindings/net/dwmac-sun8i.txt
> > > > +++ b/Documentation/devicetree/bindings/net/dwmac-sun8i.txt
> > > > @@ -39,7 +39,7 @@ Optional properties for the following compatibles:
> > > > - allwinner,leds-active-low: EPHY LEDs are active low
> > > >
> > > > Required child node of emac:
> > > > -- mdio bus node: should be named mdio
> > > > +- mdio bus node: should be labelled mdio
> > >
> > > labels do not end up in the final DT (while the names do) so why are
> > > you making this change?
> > >
> >
> > I misunderstood label/name.
> > Anyway, this contrainst should leave due to "snps,dwmac-mdio MDIOs are automatically registered"
> >
> > > >
> > > > Required properties of the mdio node:
> > > > - #address-cells: shall be 1
> > > > @@ -48,14 +48,28 @@ Required properties of the mdio node:
> > > > The device node referenced by "phy" or "phy-handle" should be a child node
> > > > of the mdio node. See phy.txt for the generic PHY bindings.
> > > >
> > > > -Required properties of the phy node with the following compatibles:
> > > > +The following compatibles require an mdio-mux node called "mdio-mux":
> > > > + - "allwinner,sun8i-h3-emac"
> > > > + - "allwinner,sun8i-v3s-emac":
> > > > +Required properties for the mdio-mux node:
> > > > + - compatible = "mdio-mux"
> > > > + - one child mdio for the integrated mdio
> > > > + - one child mdio for the external mdio if present (V3s have none)
> > > > +Required properties for the mdio-mux children node:
> > > > + - reg: 0 for internal MDIO bus, 1 for external MDIO bus
> > > > +
> > > > +The following compatibles require a PHY node representing the integrated
> > > > +PHY, under the integrated MDIO bus node if an mdio-mux node is used:
> > > > - "allwinner,sun8i-h3-emac",
> > > > - "allwinner,sun8i-v3s-emac":
> > > > +
> > > > +Required properties of the integrated phy node:
> > > > - clocks: a phandle to the reference clock for the EPHY
> > > > - resets: a phandle to the reset control for the EPHY
> > > > +- phy-is-integrated
> > > > +- Should be a child of the integrated mdio
> > >
> > > I'm not sure what you mean by that, you ask that it should (so not
> > > required?) be a child of the integrated mdio...
> > >
> >
> > I will change words to "must"
> >
> > > >
> > > > -Example:
> > > > -
> > > > +Example with integrated PHY:
> > > > emac: ethernet@1c0b000 {
> > > > compatible = "allwinner,sun8i-h3-emac";
> > > > syscon = <&syscon>;
> > > > @@ -72,13 +86,112 @@ emac: ethernet@1c0b000 {
> > > > phy-handle = <&int_mii_phy>;
> > > > phy-mode = "mii";
> > > > allwinner,leds-active-low;
> > > > +
> > > > + mdio0: mdio {
> > >
> > > (You don't label it mdio here, unlike what was asked before)
> > >
> > > > + #address-cells = <1>;
> > > > + #size-cells = <0>;
> > > > + compatible = "snps,dwmac-mdio";
> > > > + };
> > >
> > > I think Rob wanted that node gone?
> > >
> >
> > MDIO mux does not work without a parent MDIO, either gived by "parent-bus" or directly via mdio_mux_init() (like it is the case in dwmac-sun8i)
>
> Is the MDIO controller "allwinner,sun8i-h3-emac" or "snps,dwmac-mdio"?
> If the latter, then I think the node is fine, but then the mux should be
> a child node of it. IOW, the child of an MDIO controller should either
> be a mux node or slave devices.
>

It will be snps,dwmac-mdio but putting mdio-mux as a child of it (the mdio node) give me:
[ 18.175338] libphy: stmmac: probed
[ 18.175379] mdio_bus stmmac-0: /soc/ethernet@1c30000/mdio/mdio-mux has invalid PHY address
[ 18.175408] mdio_bus stmmac-0: scan phy mdio-mux at address 0
[ 18.175450] mdio_bus stmmac-0: scan phy mdio-mux at address 1
[ 18.175482] mdio_bus stmmac-0: scan phy mdio-mux at address 2
[ 18.175513] mdio_bus stmmac-0: scan phy mdio-mux at address 3
[ 18.175544] mdio_bus stmmac-0: scan phy mdio-mux at address 4
[ 18.175575] mdio_bus stmmac-0: scan phy mdio-mux at address 5
[ 18.175607] mdio_bus stmmac-0: scan phy mdio-mux at address 6
[ 18.175638] mdio_bus stmmac-0: scan phy mdio-mux at address 7
[ 18.175669] mdio_bus stmmac-0: scan phy mdio-mux at address 8
[ 18.175700] mdio_bus stmmac-0: scan phy mdio-mux at address 9
[ 18.175731] mdio_bus stmmac-0: scan phy mdio-mux at address 10
[ 18.175762] mdio_bus stmmac-0: scan phy mdio-mux at address 11
[ 18.175795] mdio_bus stmmac-0: scan phy mdio-mux at address 12
[ 18.175827] mdio_bus stmmac-0: scan phy mdio-mux at address 13
[ 18.175858] mdio_bus stmmac-0: scan phy mdio-mux at address 14
[ 18.175889] mdio_bus stmmac-0: scan phy mdio-mux at address 15
[ 18.175919] mdio_bus stmmac-0: scan phy mdio-mux at address 16
[ 18.175951] mdio_bus stmmac-0: scan phy mdio-mux at address 17
[ 18.175982] mdio_bus stmmac-0: scan phy mdio-mux at address 18
[ 18.176014] mdio_bus stmmac-0: scan phy mdio-mux at address 19
[ 18.176045] mdio_bus stmmac-0: scan phy mdio-mux at address 20
[ 18.176076] mdio_bus stmmac-0: scan phy mdio-mux at address 21
[ 18.176107] mdio_bus stmmac-0: scan phy mdio-mux at address 22
[ 18.176139] mdio_bus stmmac-0: scan phy mdio-mux at address 23
[ 18.176170] mdio_bus stmmac-0: scan phy mdio-mux at address 24
[ 18.176202] mdio_bus stmmac-0: scan phy mdio-mux at address 25
[ 18.176233] mdio_bus stmmac-0: scan phy mdio-mux at address 26
[ 18.176271] mdio_bus stmmac-0: scan phy mdio-mux at address 27
[ 18.176320] mdio_bus stmmac-0: scan phy mdio-mux at address 28
[ 18.176371] mdio_bus stmmac-0: scan phy mdio-mux at address 29
[ 18.176420] mdio_bus stmmac-0: scan phy mdio-mux at address 30
[ 18.176452] mdio_bus stmmac-0: scan phy mdio-mux at address 31

Adding a fake <reg> to mdio-mux remove it.
Does it is acceptable ? or perhaps patching of_mdiobus_register() to not scan node with compatible "mdio-mux".

> >
> > > > + mdio-mux {
> > > > + compatible = "mdio-mux";
> > > > + #address-cells = <1>;
> > > > + #size-cells = <0>;
> > > > +
> > > > + int_mdio: mdio@1 {
> > > > + reg = <0>;
>
> unit address of 1 and reg prop of 0 don't match. Build your dtb with
> W=2.
>

reg are arbitrary value (like mdio-mux-mmioreg), but in our case it is easy to fix this warning.

Thanks