linux-kernel - Re: [PATCH 03/22] clk: renesas: r9a09g047: Add CLK

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Message-ID: <CAMuHMdW-CSVVDHXEXA5GwjERKaUHO4xxd9HCX0nez0vtCT18PA@mail.gmail.com>
Date: Fri, 9 Jan 2026 19:35:43 +0100
From: Geert Uytterhoeven <geert@...ux-m68k.org>
To: Tommaso Merciai <tommaso.merciai.xr@...renesas.com>
Cc: tomm.merciai@...il.com, linux-renesas-soc@...r.kernel.org, 
	biju.das.jz@...renesas.com, Andrzej Hajda <andrzej.hajda@...el.com>, 
	Neil Armstrong <neil.armstrong@...aro.org>, Robert Foss <rfoss@...nel.org>, 
	Laurent Pinchart <Laurent.pinchart@...asonboard.com>, Jonas Karlman <jonas@...boo.se>, 
	Jernej Skrabec <jernej.skrabec@...il.com>, David Airlie <airlied@...il.com>, 
	Simona Vetter <simona@...ll.ch>, Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
	Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>, Rob Herring <robh@...nel.org>, 
	Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, 
	Michael Turquette <mturquette@...libre.com>, Stephen Boyd <sboyd@...nel.org>, 
	Magnus Damm <magnus.damm@...il.com>, dri-devel@...ts.freedesktop.org, 
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org, 
	linux-clk@...r.kernel.org
Subject: Re: [PATCH 03/22] clk: renesas: r9a09g047: Add CLK_PLLDSI{0,1} clocks

On Wed, 26 Nov 2025 at 15:08, Tommaso Merciai
<tommaso.merciai.xr@...renesas.com> wrote:
> Add support for the PLLDSI{0,1} clocks in the r9a09g047 CPG driver.
>
> Introduce CLK_PLLDSI{0,1} also, introduce the
> rzg3e_cpg_pll_dsi{0,1}_limits structures to describe the frequency
> constraints specific to the RZ/G3E SoC.
>
> On Renesas RZ/G3E:
>
>  - PLLDSI0 maximum output frequency: 1218 MHz
>  - PLLDSI1 maximum output frequency: 609 MHz
>
> These limits are enforced through the newly added
> RZG3E_CPG_PLL_DSI{0,1}_LIMITS().
>
> Signed-off-by: Tommaso Merciai <tommaso.merciai.xr@...renesas.com>

> --- a/include/linux/clk/renesas.h
> +++ b/include/linux/clk/renesas.h
> @@ -153,6 +153,26 @@ struct rzv2h_pll_div_pars {
>                 .k = { .min = -32768, .max = 32767 },                   \
>         }                                                               \
>
> +#define RZG3E_CPG_PLL_DSI0_LIMITS(name)                                        \
> +       static const struct rzv2h_pll_limits (name) = {                 \
> +               .fout = { .min = 25 * MEGA, .max = 1218 * MEGA },       \
> +               .fvco = { .min = 1600 * MEGA, .max = 3200 * MEGA },     \
> +               .m = { .min = 64, .max = 533 },                         \
> +               .p = { .min = 1, .max = 4 },                            \
> +               .s = { .min = 0, .max = 6 },                            \
> +               .k = { .min = -32768, .max = 32767 },                   \
> +       }                                                               \
> +
> +#define RZG3E_CPG_PLL_DSI1_LIMITS(name)                                        \
> +       static const struct rzv2h_pll_limits (name) = {                 \
> +               .fout = { .min = 25 * MEGA, .max = 609 * MEGA },        \
> +               .fvco = { .min = 1600 * MEGA, .max = 3200 * MEGA },     \
> +               .m = { .min = 64, .max = 533 },                         \
> +               .p = { .min = 1, .max = 4 },                            \
> +               .s = { .min = 0, .max = 6 },                            \
> +               .k = { .min = -32768, .max = 32767 },                   \
> +       }                                                               \
> +
>  #ifdef CONFIG_CLK_RZV2H
>  bool rzv2h_get_pll_pars(const struct rzv2h_pll_limits *limits,
>                         struct rzv2h_pll_pars *pars, u64 freq_millihz);

So these definitions are shared with the DRM driver, and thus are a
hard dependency from DRM to clock driver.

Reviewed-by: Geert Uytterhoeven <geert+renesas@...der.be>

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-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