Re: [PATCH v3 2/8] dt-bindings: can: renesas,rcar-canfd: Document RZ/G3S SoC

[Geert Uytterhoeven]

On Tue, 14 Jul 2026 at 19:33, Claudiu Beznea
<claudiu.beznea+renesas@xxxxxxxxx> wrote:
> From: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx>
>
> The CAN FD controller found on the Renesas RZ/G3S SoC is largely compatible
> with the variant present on the RZ/G3E SoC. The main differences are:
> - the RZ/G3S provides only two CAN FD channels
> - the RZ/G3S supports only CAN FD operation; the Channel n CAN FD
>   Configuration Register does not implement the bits used to select
>   classical CAN-only mode (bit 30) or CAN FD-only mode (bit 28);
>   consequently, bit 31 (CAN FD Frame Distinction Enable) of the same
>   register is also not implemented
> - some bits in several registers (mainly reserved or status bits) are
>   read-write on the RZ/G3S but read-only on the RZ/G3E; their behavior is
>   otherwise identical: the bits read back as 0 on both SoCs and software
>   is allowed to write only 0 to them on the RZ/G3S
> - the RZ/G3S provides 256 acceptance filters, compared to 768 on the
>   RZ/G3E
> - the RZ/G3S can use PCLK clock as the CAN FD clock source through an
>   internal clock divider, while also supporting an external CAN FD clock
>   source
>
> Since:
> - the SoC clock generator provides to the CAN IP only the peripheral and
>   the RAM clocks
> - when sourced from the peripheral clock, the CAN-FD clock is obtained
>   inside the IP itself by dividing the peripheral clock
> - the assigned-clocks and assigned-clock-rates properties are specific to
>   the CAN-FD clock
> the assigned-clocks and assigned-clock-rates properties were dropped from
> the required properties list of the Renesas RZ/G3S SoC.
>
> Add documentation for the Renesas RZ/G3S SoC.
>
> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx>

Reviewed-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>

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