Hi Chris,

On Wed, Feb 15, 2017 at 6:33 PM, Chris Brandt [off-list ref] wrote:

On Tuesday, February 14, 2017, Geert Uytterhoeven wrote:

quoted

quoted

+Required properties:
+  - compatible: must be one or more of the following:
+    - "renesas,r7s72100-reset" for the r7s72100 SoC
+    - "renesas,wdt-reset"
+                This is a fallback for the above renesas,*-reset
+entries

Please use "renesas,r7s72100-wdt". DT describes the hardware (watchdog),
not the software policy (use it for reset only, as a max. timeout of 125
ms is too short for a usable watchdog).

I had a look at:

  Documentation/devicetree/bindings/watchdog/renesas-wdt.txt

Which has:

Required properties:
- compatible : Should be "renesas,<soctype>-wdt", and
               "renesas,rcar-gen3-wdt" as fallback.
               Examples with soctypes are:
                 - "renesas,r8a7795-wdt" (R-Car H3)
                 - "renesas,r8a7796-wdt" (R-Car M3-W)


So in my 'renesas-reset.txt' should I do:

As "reset" is software policy, perhaps you should instead extend the existing
binding document Documentation/devicetree/bindings/watchdog/renesas-wdt.txt?

Nothing says you have to use the same Linux driver for R-Car Gen3 and
RZ/A1.

A. "renesas,r7s72100-wdt", "renesas,rz-wdt"

Please don't use plain "rz", as RZ/A, RZ/G, and RZ/T are completely different
beasts.

  or just:

B. "renesas,r7s72100-wdt"   (no fallback, change the driver to add new SoCs)

Do you know if future RZ/A SoCs will use the exact same type of WDT?
If yes, you can document both "renesas,r7s72100-wdt" and "renesas,rza-wdt",
and let the driver match against the latter.
Else I'd just document and match against "renesas,r7s72100-wdt".

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

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