Hello Geert,

Thank you for your feedback.

Subject: Re: [PATCH 3/3] dt-bindings: can: rcar_can: Add r8a774a1 support

Hi Fabrizio,

On Thu, Aug 23, 2018 at 3:08 PM Fabrizio Castro
[off-list ref] wrote:>

quoted

Document RZ/G2M (r8a774a1) SoC specific bindings and RZ/G2
generic bindings.

Signed-off-by: Fabrizio Castro <redacted>
Signed-off-by: Chris Paterson <redacted>
Reviewed-by: Biju Das <redacted>

Thanks for your patch!

quoted

--- a/Documentation/devicetree/bindings/net/can/rcar_can.txt
+++ b/Documentation/devicetree/bindings/net/can/rcar_can.txt

@@ -4,6 +4,7 @@ Renesas R-Car CAN controller Device Tree Bindings
 Required properties:
 - compatible: "renesas,can-r8a7743" if CAN controller is a part of R8A7743 SoC.
              "renesas,can-r8a7745" if CAN controller is a part of R8A7745 SoC.
+             "renesas,can-r8a774a1" if CAN controller is a part of R8A774A1 SoC.

Looks good to me.

quoted

              "renesas,can-r8a7778" if CAN controller is a part of R8A7778 SoC.
              "renesas,can-r8a7779" if CAN controller is a part of R8A7779 SoC.
              "renesas,can-r8a7790" if CAN controller is a part of R8A7790 SoC.

@@ -17,6 +18,7 @@ Required properties:
              "renesas,rcar-gen2-can" for a generic R-Car Gen2 or RZ/G1
              compatible device.
              "renesas,rcar-gen3-can" for a generic R-Car Gen3 compatible device.
+             "renesas,rzg-gen2-can" for a generic RZ/G2 compatible device.

AFAIK, the actual CAN module in RZ/G2M is fully compatible with the CAN
module in R-Car Gen3 SoCs. The lack of clkp2 is merely an integration
difference: as RZ/G2 SoCs do not have the CANFD module, and their CPG block
doesn't provide the CANFD clock (so the CAN device node in DT cannot refer
to that clock anyway).

Hence I don't think there's a need to introduce a "renesas,rzg-gen2-can"
compatible value.

Agreed, will drop RZ/G2 specific compatible string.

quoted

              When compatible with the generic version, nodes must list the
              SoC-specific version corresponding to the platform first
              followed by the generic version.

@@ -24,7 +26,9 @@ Required properties:
 - reg: physical base address and size of the R-Car CAN register map.
 - interrupts: interrupt specifier for the sole interrupt.
 - clocks: phandles and clock specifiers for 3 CAN clock inputs.

You still have "3" here. Perhaps
"Must contain a phandle and clock-specifier pair for each entry in
clock-names."?

Good spot, we overlooked it.

quoted

-- clock-names: 3 clock input name strings: "clkp1", "clkp2", "can_clk".
+- clock-names: 2 clock input name strings for RZ/G2: "clkp1", "can_clk".
+              3 clock input name strings for every other SoC: "clkp1", "clkp2",
+              "can_clk".

OK.

quoted

@@ -41,8 +45,9 @@ using the below properties:
 Optional properties:
 - renesas,can-clock-select: R-Car CAN Clock Source Select. Valid values are:
                            <0x0> (default) : Peripheral clock (clkp1)
-                           <0x1> : Peripheral clock (clkp2)
-                           <0x3> : Externally input clock
+                           <0x1> : Peripheral clock (clkp2) (not supported by
+                                   RZ/G2 devices)
+                           <0x3> : External input clock

I already expressed my feelings about this property in my reply to the first
patch ;-)

I know, I am not super happy about it either, maybe we will get a proper solution for this at some point in the future.

Thanks,
Fab

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

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