Re: [PATCH v3 1/5] clk: renesas: rzv2h-cpg: Use per-SoC PLL reference frequency for calculations

[Geert Uytterhoeven]

Hi Prabhakar,

On Mon, 15 Jun 2026 at 12:48, Prabhakar <prabhakar.csengg@xxxxxxxxx> wrote:
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
>
> Introduce a per-SoC PLL reference input frequency parameter to avoid
> relying on a hardcoded 24MHz constant during PLL configuration math.
>
> Add an input_fref member to struct rzv2h_pll_limits. In the core
> calculation helper rzv2h_get_pll_pars(), derive the base input clock
> rate from limits->input_fref, utilizing the conditional ternary operator
> to fall back to 24MHz if the struct field is left uninitialized (0), and
> drop the obsolete macro RZ_V2H_OSC_CLK_IN_MEGA.
>
> This abstraction permits the reuse of the common PLL divider logic on
> newer SoC platforms like the RZ/T2H, which feature a 48 MHz PLL reference
> clock input instead of the 24 MHz signal used by RZ/V2H(P), without
> disrupting existing platforms.
>
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>

Thanks for your patch!

> --- a/include/linux/clk/renesas.h
> +++ b/include/linux/clk/renesas.h
> @@ -53,6 +53,9 @@ static inline void rzg2l_cpg_dsi_div_set_divider(u8 divider, int target) { }
>   * various parameters used to configure a PLL. These limits ensure
>   * the PLL operates within valid and stable ranges.
>   *
> + * @input_fref: Reference input frequency to the PLL (in MHz). If set

"in Hz", as pointed out by Sashiko.

> + * to 0, a default value of 24MHz is used.
> + *
>   * @fout: Output frequency range (in MHz)
>   * @fout.min: Minimum allowed output frequency
>   * @fout.max: Maximum allowed output frequency
> @@ -78,6 +81,8 @@ static inline void rzg2l_cpg_dsi_div_set_divider(u8 divider, int target) { }
>   * @k.max: Maximum delta-sigma value
>   */
>  struct rzv2h_pll_limits {
> +       u32 input_fref;
> +
>         struct {
>                 u32 min;
>                 u32 max;

The rest LGTM, so with the above fixed:
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