RE: [PATCH] DT: add MDIO node for FMan node

[Shaohui Xie <Shaohui.Xie@xxxxxxxxxxxxx>]

> -----Original Message-----
> From: Wood Scott-B07421
> Sent: Tuesday, November 11, 2014 8:23 AM
> To: shh.xie@xxxxxxxxx
> Cc: linuxppc-dev@xxxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; Medve
> Emilian-EMMEDVE1; Xie Shaohui-B21989
> Subject: Re: [PATCH] DT: add MDIO node for FMan node
> 
> On Tue, 2014-11-04 at 19:56 +0800, shh.xie@xxxxxxxxx wrote:
> > From: Shaohui Xie <Shaohui.Xie@xxxxxxxxxxxxx>
> >
> > This binding is for FMan MDIO, it covers FMan v2 & FMan v3.
> >
> > Signed-off-by: Shaohui Xie <Shaohui.Xie@xxxxxxxxxxxxx>
> > ---
> > based on http://patchwork.ozlabs.org/patch/390351/
> > for 'next' of
> > git://git.kernel.org/pub/scm/linux/kernel/git/scottwood/linux.git
> 
> Are there any other FMan pieces that are missing from the above patch?
[S.H] I'm adding Igal for this comment.

> 
> >  .../devicetree/bindings/powerpc/fsl/fman.txt       | 69
> ++++++++++++++++++++++
> >  1 file changed, 69 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/powerpc/fsl/fman.txt
> > b/Documentation/devicetree/bindings/powerpc/fsl/fman.txt
> > index da8e5f2..83c2f14 100644
> > --- a/Documentation/devicetree/bindings/powerpc/fsl/fman.txt
> > +++ b/Documentation/devicetree/bindings/powerpc/fsl/fman.txt
> > @@ -7,6 +7,7 @@ CONTENTS
> >    - FMan MURAM Node
> >    - FMan dTSEC/XGEC/mEMAC Node
> >    - FMan IEEE 1588 Node
> > +  - FMan MDIO Node
> >    - Example
> >
> >
> > ======================================================================
> > ======= @@ -352,6 +353,67 @@ ptp-timer@fe000 {  };
> >
> >
> > ======================================================================
> > =======
> > +FMan MDIO Node
> > +
> > +DESCRIPTION
> > +
> > +The MDIO is a bus to which the PHY devices are connected.
> > +
> > +PROPERTIES
> > +
> > +- compatible
> > +		Usage: required
> > +		Value type: <stringlist>
> > +		Definition: A standard property.
> > +		Must include "fsl,fman-mdio" for 1 Gb/s MDIO from FMan v2.
> > +		Must include "fsl,fman-xmdio" for 10 Gb/s MDIO from FMan v2.
> > +		Must include "fsl,fman-memac-mdio" for 1/10 Gb/s MDIO from
> > +		FMan v3.
> > +
> > +- reg
> > +		Usage: required
> > +		Value type: <prop-encoded-array>
> > +		Definition: A standard property.
> > +
> > +- bus-frequency
> > +		Usage: optional
> > +		Value type: <u32>
> > +		Definition: Default MDIO bus clock speed.
> 
> Use clocks/clock-names
[S.H] The MDIO uses Fman clock and divides it to a proper value which is specified by this property.

> 
> > +- interrupts
> > +		Usage: optional
> > +		Value type: <prop-encoded-array>
> > +		Definition: MDIO controller event interrupts.
> 
> One interrupt or multiple?
[S.H] One for 1 Gb/s, one for 10 Gb/s.

> 
> > +
> > +- type
> > +		Usage: required for FMan v3
> > +		Value type: <stringlist>
> > +		Definition: A standard property.
> 
> What standard is "type" defined in?
[S.H] It's to differentiate between the internal and external MDIO, I'm not quite sure about naming it, or what could be better way to differentiate the MDIOs?

> 
> > +		FMan v3 has internal MDIO for internal PCS(Physical Coding
> > +		Sublayer) PHYs and external MDIO for external PHYs.
> > +		The settings and programming routines for internal/external
> > +		MDIO are different. Must include "internal" for internal MDIO,
> > +		must include "external" for external MDIO.
> 
> I assume fman v2 is always internal?  How about a boolean "fsl,fman-
> internal-phy" property instead?
[S.H] Both Fman v2 & v3 have internal/external MDIO, Fman v2 uses internal MDIO for TBI operations to set the SGMII PHY, 
The TBI implements transmit/receive portions of PCS, it's not used in Linux. The PCS on Fman V3 are not just for SGMII, it has more implementations, it's used in Linux.

> 
> > +
> > +EXAMPLE
> > +
> > +Example for FMan v2:
> > +
> > +mdio@f1000 {
> > +	compatible = "fsl,fman-xmdio";
> > +	reg = <0xf1000 0x1000>;
> > +};
> > +
> > +Example for FMan v3:
> > +
> > +mdio@fd000 {
> > +	compatible = "fsl,fman-memac-mdio";
> > +	reg = <0xfd000 0x1000>;
> > +	bus-frequency = <2500000>;
> > +	type = "external";
> > +};
> > +
> > +=====================================================================
> > +========
> >  Example
> >
> >  fman@400000 {
> > @@ -526,4 +588,11 @@ fman@400000 {
> >  		compatible = "fsl,fman-ptp-timer";
> >  		reg = <0xfe000 0x1000>;
> >  	};
> > +
> > +	mdio@fd000 {
> > +		compatible = "fsl,fman-memac-mdio";
> > +		reg = <0xfd000 0x1000>;
> > +		bus-frequency = <2500000>;
> > +		type = "external";
> > +	};
> >  };
> 
> The rest of the example is fman v2; don't mix an fman v3 node in with
> that.
[S.H] OK. Will fix it.

Thanks!
Shaohui
 

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