netdev - Re: [PATCH v2 3/5] ARM: sun8i: dt: Add DT bindings documentation for Allwinner sun8i-emac

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Message-ID: <20160728134031.GC7582@Red>
Date:	Thu, 28 Jul 2016 15:40:31 +0200
From:	LABBE Corentin <clabbe.montjoie@...il.com>
To:	Maxime Ripard <maxime.ripard@...e-electrons.com>
Cc:	robh+dt@...nel.org, mark.rutland@....com, wens@...e.org,
	linux@...linux.org.uk, davem@...emloft.net, netdev@...r.kernel.org,
	devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org, linux-sunxi@...glegroups.com
Subject: Re: [PATCH v2 3/5] ARM: sun8i: dt: Add DT bindings documentation for
 Allwinner sun8i-emac

On Thu, Jul 21, 2016 at 09:55:19AM +0200, Maxime Ripard wrote:
> Hi,
> 
> On Wed, Jul 20, 2016 at 10:03:18AM +0200, LABBE Corentin wrote:
> > This patch adds documentation for Device-Tree bindings for the
> > Allwinner sun8i-emac driver.
> > 
> > Signed-off-by: LABBE Corentin <clabbe.montjoie@...il.com>
> > ---
> >  .../bindings/net/allwinner,sun8i-emac.txt          | 65 ++++++++++++++++++++++
> >  1 file changed, 65 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/net/allwinner,sun8i-emac.txt
> > 
> > diff --git a/Documentation/devicetree/bindings/net/allwinner,sun8i-emac.txt b/Documentation/devicetree/bindings/net/allwinner,sun8i-emac.txt
> > new file mode 100644
> > index 0000000..4bf4e53
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/net/allwinner,sun8i-emac.txt
> > @@ -0,0 +1,65 @@
> > +* Allwinner sun8i EMAC ethernet controller
> > +
> > +Required properties:
> > +- compatible: "allwinner,sun8i-a83t-emac", "allwinner,sun8i-h3-emac",
> > +		or "allwinner,sun50i-a64-emac"
> > +- reg: address and length of the register sets for the device.
> > +- reg-names: should be "emac" and "syscon", matching the register sets
> 
> Blindly mapping a register of some other device on the SoC doesn't
> look very reasonable.
> 

As we discuss after this mail on IRC, this register is dedicated to EMAC.

> > +- interrupts: interrupt for the device
> > +- clocks: A phandle to the reference clock for this device
> > +- clock-names: should be "ahb"
> > +- resets: A phandle to the reset control for this device
> > +- reset-names: should be "ahb"
> > +- phy-mode: See ethernet.txt
> > +- phy or phy-handle: See ethernet.txt
> > +- #address-cells: shall be 1
> > +- #size-cells: shall be 0
> > +
> > +"allwinner,sun8i-h3-emac" also requires:
> > +- clocks: an extra phandle to the reference clock for the EPHY
> > +- clock-names: an extra "ephy" entry matching the clocks property
> > +- resets: an extra phandle to the reset control for the EPHY
> > +- resets-names: an extra "ephy" entry matching the resets property
> 
> Shouldn't that be attached to the phy itself?
> 

Ok I will move them.

> > +See ethernet.txt in the same directory for generic bindings for ethernet
> > +controllers.
> > +
> > +The device node referenced by "phy" or "phy-handle" should be a child node
> > +of this node. See phy.txt for the generic PHY bindings.
> > +
> > +Optional properties:
> > +- phy-supply: phandle to a regulator if the PHY needs one
> > +- phy-io-supply: phandle to a regulator if the PHY needs a another one for I/O.
> > +		 This is sometimes found with RGMII PHYs, which use a second
> > +		 regulator for the lower I/O voltage.
> > +- allwinner,tx-delay: The setting of the TX clock delay chain
> > +- allwinner,rx-delay: The setting of the RX clock delay chain
> 
> In which unit? What is the default value?
> 

The unit is unknown to me, but I have added a comment for the default and acceptable range value.

> > +
> > +The TX/RX clock delay chain settings are board specific.
> > +
> > +Optional properties for "allwinner,sun8i-h3-emac":
> > +- allwinner,use-internal-phy: Use the H3 SoC's internal E(thernet) PHY
> 
> Can't that be derived from the presence of the phy property?
> 

Yes, I have reworked the "variant" of the driver for easily handling this.

> > +- allwinner,leds-active-low: EPHY LEDs are active low
> 
> That also seems PHY related. Overall, I feel like we really need a phy
> node for the internal phy.
> 

Moved also in the phy node.

> Maxime
> 
> -- 
> Maxime Ripard, Free Electrons
> Embedded Linux and Kernel engineering
> http://free-electrons.com

Best regards

Thanks

LABBE Corentin