Re: [PATCH v2 14/17] riscv: dts: microchip: add fpga fabric section to icicle kit

[Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>]

Hi Conor,

On Fri, Dec 17, 2021 at 4:32 PM <Conor.Dooley@xxxxxxxxxxxxx> wrote:
> On 17/12/2021 13:43, Geert Uytterhoeven wrote:
> > On Fri, Dec 17, 2021 at 10:33 AM <conor.dooley@xxxxxxxxxxxxx> wrote:
> >> From: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
> >>
> >> Split the device tree for the Microchip MPFS into two sections by adding
> >> microchip-mpfs-fabric.dtsi, which contains peripherals contained in the
> >> FPGA fabric.
> >>
> >> Signed-off-by: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
> >
> > Thanks for your patch!
> >
> >> --- /dev/null
> >> +++ b/arch/riscv/boot/dts/microchip/microchip-mpfs-fabric.dtsi
> >> @@ -0,0 +1,13 @@
> >> +// SPDX-License-Identifier: (GPL-2.0 OR MIT)
> >> +/* Copyright (c) 2020-2021 Microchip Technology Inc */
> >> +
> >> +/ {
> >> +       corePWM0: pwm@41000000 {
> >> +               compatible = "microchip,corepwm";
> >> +               reg = <0x0 0x41000000 0x0 0xF0>;
> >> +               microchip,sync-update = /bits/ 8 <0>;
> >> +               #pwm-cells = <2>;
> >> +               clocks = <&clkcfg CLK_FIC3>;
> >> +               status = "disabled";
> >> +       };
> >
> > I'm wondering if these should be grouped under a "fabric" subnode,
> > like we have an "soc" subnode for on-SoC devices? Rob?
> >
> > BTW, do you already have a naming plan for different revisions of
> > FPGA fabric cores?
> Not yet (assuming you mean specifically how we will handle it in the
> device tree) - although i was talking to someone about it yesterday.
> It's possible that we might handle that via a register, but if you have
> a suggestion or some precedence that you're aware of that would be useful.
>
> The actual naming convention of the IP cores themselves, yeah. I will
> dig it up for you on Monday.

I meant what if corepwm is enhanced, and how to detect that?

SiFive uses an integer version number, even for hard cores[1].
OpenCores uses an "-rtlsvnN" suffix (isn't svn dead? ;-)
No idea what e.g. LiteX and Microwatt are planning.

[1] Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt


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