Date: Wed, 13 Sep 2017 13:20:04 -0500
From: Rob Herring <robh@kernel.org>
To: Corentin Labbe <clabbe.montjoie@gmail.com>
Cc: Maxime Ripard <maxime.ripard@free-electrons.com>, mark.rutland@arm.com,
        wens@csie.org, linux@armlinux.org.uk, catalin.marinas@arm.com,
        will.deacon@arm.com, peppe.cavallaro@st.com, alexandre.torgue@st.com,
        andrew@lunn.ch, f.fainelli@gmail.com, netdev@vger.kernel.org,
        devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5 05/10] dt-bindings: net: dwmac-sun8i: update
 documentation about integrated PHY
Message-ID: <20170913182004.uniyo5opeilcfk7r@rob-hp-laptop>
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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@gmail.com>
> > > ---
> > >  .../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.

> 
> > > +	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.

> > > +			#address-cells = <1>;
> > > +			#size-cells = <0>;
> > > +			int_mii_phy: ethernet-phy@1 {
> > > +				reg = <1>;
> > > +				clocks = <&ccu CLK_BUS_EPHY>;
> > > +				resets = <&ccu RST_BUS_EPHY>;
> > > +				phy-is-integrated

Missing ;

> > > +			};
> > > +		};
> > 
> > ... And in your example it's a child of the mdio mux?
> > 
> 
> So I confirm, integrated PHY must be a child of integrated MDIO (that must be a child of mdio-mux).
> The example is good.
> 
> > > +		ext_mdio: mdio@0 {
> > > +			reg = <1>;

Another unit address mismatch.

Rob