Hi Clément,
On Fri, May 20, 2022 at 10:33 AM Clément Léger
<clement.leger@xxxxxxxxxxx> wrote:
> Le Fri, 20 May 2022 10:25:37 +0200,
> Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> a écrit :
> > On Fri, May 20, 2022 at 10:14 AM Clément Léger
> > <clement.leger@xxxxxxxxxxx> wrote:
> > > Le Fri, 20 May 2022 09:18:58 +0200,
> > > Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> a écrit :
> > > > On Thu, May 19, 2022 at 5:32 PM Clément Léger <clement.leger@xxxxxxxxxxx> wrote:
> > > > > RZ/N1 SoC includes two MAC named GMACx that are compatible with the
> > > > > "snps,dwmac" driver. GMAC1 is connected directly to the MII converter
> > > > > port 1. GMAC2 however can be used as the MAC for the switch CPU
> > > > > management port or can be muxed to be connected directly to the MII
> > > > > converter port 2. This commit add description for the GMAC2 which will
> > > > > be used by the switch description.
> > > > >
> > > > > Signed-off-by: Clément Léger <clement.leger@xxxxxxxxxxx>
> >
> > > > > --- a/arch/arm/boot/dts/r9a06g032.dtsi
> > > > > +++ b/arch/arm/boot/dts/r9a06g032.dtsi
> > > > > @@ -200,6 +200,23 @@ nand_controller: nand-controller@40102000 {
> > > > > status = "disabled";
> > > > > };
> > > > >
> > > > > + gmac2: ethernet@44002000 {
> > > > > + compatible = "snps,dwmac";
> > > >
> > > > Does this need an SoC-specific compatible value?
> > >
> > > Indeed, it might be useful to introduce a specific SoC compatible since
> > > in a near future, there might be some specific support for that gmac.
> > > Here is an overview of the gmac connection on the SoC:
> > >
> > > ┌─────────┐ ┌──────────┐
> > > │ │ │ │
> > > │ GMAC2 │ │ GMAC1 │
> > > │ │ │ │
> > > └───┬─────┘ └─────┬────┘
> > > │ │
> > > │ │
> > > │ │
> > > ┌────▼──────┐ │
> > > │ │ │
> > > ┌────────────────────────────┤ SWITCH │ │
> > > │ │ │ │
> > > │ ┌─────────────────┴─┬────┬────┘ │
> > > │ │ ┌──────┘ │ │
> > > │ │ │ │ │
> > > ┌────▼──────────▼────────────▼───────────▼─────────────▼────┐
> > > │ MII Converter │
> > > │ │
> > > │ │
> > > │ port 1 port 2 port 3 port 4 port 5 │
> > > └───────────────────────────────────────────────────────────┘
> > >
> > > As you can see, the GMAC1 is directly connected to MIIC converter and
> > > thus will need a "pcs-handle" property to point on the MII converter
> > > port whereas the GMAC2 is directly connected to the switch in GMII.
> > >
> > > Is "renesas,r9a06g032-gmac2", "renesas,rzn1-switch-gmac2" looks ok
> > > for you for this one ?
> >
> > Why "switch" in the family-specific value, but not in the SoC-specific
> > value?
>
> That's a typo, switch should be removed.
OK.
> > Are GMAC1 and GMAC2 really different, or are they identical, and is
> > the only difference in the wiring, which can be detected at run-time
> > using this "pcs-handle" property? If they're identical, they should
> > use the same compatible value.
>
> They are actually identical except the requirement for a "pcs-handle"
> for gmac1. I thought about using different compatible to enforce this by
> making it "required" with the "renesas,r9a06g032-gmac1" compatible but
> not the "renesas,r9a06g032-gmac2" one. If it's ok for you to let it
> optional and use a single compatible, I'm ok with that !
OK to make it optional. Thanks!
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
