Re: [PATCH v3 2/3] dt-bindings: phy: Add constants for lan966x serdes

[Horatiu Vultur <horatiu.vultur@microchip.com>]

The 10/19/2021 08:38, Rob Herring wrote:
> 
> On Tue, Oct 19, 2021 at 4:11 AM Horatiu Vultur
> <horatiu.vultur@microchip.com> wrote:
> >
> > The 10/18/2021 14:28, Rob Herring wrote:
> > >
> > > On Fri, Oct 15, 2021 at 02:39:19PM +0200, Horatiu Vultur wrote:
> > > > Lan966x has: 2 integrated PHYs, 3 SerDes and 2 RGMII interfaces. Which
> > > > requires to be muxed based on the HW representation.
> > > >
> > > > So add constants for each interface to be able to distinguish them.
> > > >
> > > > Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
> > > > ---
> > > >  include/dt-bindings/phy/phy-lan966x-serdes.h | 14 ++++++++++++++
> > > >  1 file changed, 14 insertions(+)
> > > >  create mode 100644 include/dt-bindings/phy/phy-lan966x-serdes.h
> > > >
> > > > diff --git a/include/dt-bindings/phy/phy-lan966x-serdes.h b/include/dt-bindings/phy/phy-lan966x-serdes.h
> > > > new file mode 100644
> > > > index 000000000000..8a05f93ecf41
> > > > --- /dev/null
> > > > +++ b/include/dt-bindings/phy/phy-lan966x-serdes.h
> > > > @@ -0,0 +1,14 @@
> > > > +/* SPDX-License-Identifier: (GPL-2.0 OR MIT) */
> > > > +
> > > > +#ifndef __PHY_LAN966X_SERDES_H__
> > > > +#define __PHY_LAN966X_SERDES_H__
> > > > +
> > > > +#define PHY(x)               (x)
> > > > +#define PHY_MAX              PHY(2)
> > > > +#define SERDES6G(x)  (PHY_MAX + 1 + (x))
> > > > +#define SERDES6G_MAX SERDES6G(3)
> > > > +#define RGMII(x)     (SERDES6G_MAX + 1 + (x))
> > > > +#define RGMII_MAX    RGMII(2)
> > > > +#define SERDES_MAX   (RGMII_MAX + 1)
> > >
> > > I still don't understand. #phy-cells description says we have:
> > >
> > > <port idx> <serdes idx>
> > >
> > > But here it's 3 numbers. How are these defines used to fill in the 2
> > > cells?
> >
> > Actually they are still only a number. Or maybe I am missing something.
> 
> So all the defines apply to the 2nd cell? That's what's missing.

Exactly.

> The cell description needs to spell all this out. 3 different modes or
> whatever. Explain what the h/w is comprised of in the top level
> 'description'.

I will add this description.

> 
> >
> > Maybe an example will help:
> >
> > ---
> > serdes: serdes@e2004010 {
> >     compatible = "microchip,lan966x-serdes";
> >     reg = <0xe202c000 0x9c>, <0xe2004010 0x4>;
> >     #phy-cells = <2>;
> > };
> >
> > &port0 {
> >     ...
> >     phys = <&serdes 0 SERDES6G(1)>;
> >     ...
> > };
> >
> > &port1 {
> >     ...
> >     phys = <&serdes 1 PHY(0)>;
> 
> I think CU was better, just needed some comments. PHY is pretty vague.

Same here, I will update it.

> 
> >     ...
> > }
> >
> > ...
> > ---
> >
> > Here are some existing examples based on which I have created this patch
> > series:
> > https://elixir.bootlin.com/linux/v5.15-rc6/source/arch/mips/boot/dts/mscc/ocelot_pcb120.dts#L99
> 
> None of which use PHY() or RGMII()...
> 
> 
> > https://elixir.bootlin.com/linux/v5.15-rc6/source/arch/mips/boot/dts/mscc/ocelot.dtsi#L274
> >
> > >
> > > Rob
> >
> > --
> > /Horatiu

-- 
/Horatiu