linux-kernel - Re: [PATCH v2 03/13] pinctrl: renesas: pinctrl-rzg2l: Allow more bits for pin configuration

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Date: Wed, 22 May 2024 12:19:31 +0200
From: Geert Uytterhoeven <geert@...ux-m68k.org>
To: Prabhakar <prabhakar.csengg@...il.com>
Cc: Linus Walleij <linus.walleij@...aro.org>, Rob Herring <robh@...nel.org>, 
	Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, 
	Magnus Damm <magnus.damm@...il.com>, linux-renesas-soc@...r.kernel.org, 
	linux-gpio@...r.kernel.org, devicetree@...r.kernel.org, 
	linux-kernel@...r.kernel.org, Biju Das <biju.das.jz@...renesas.com>, 
	Fabrizio Castro <fabrizio.castro.jz@...esas.com>, 
	Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
Subject: Re: [PATCH v2 03/13] pinctrl: renesas: pinctrl-rzg2l: Allow more bits
 for pin configuration

Hi Prabhakar,

On Tue, Apr 23, 2024 at 7:59 PM Prabhakar <prabhakar.csengg@...il.com> wrote:
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
>
> The pin configuration bits have been growing for every new SoCs being
> added for the pinctrl-rzg2l driver which would mean updating the macros
> every time for each new configuration. To avoid this allocate additional
> bits for pin configuration by relocating the known fixed bits to the very
> end of the configuration.
>
> Also update the size of 'cfg' to 'u64' to allow more configuration bits in
> the 'struct rzg2l_variable_pin_cfg'.
>
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> ---
> RFC->v2
> - Merged the macros and rzg2l_variable_pin_cfg changes into single patch
> - Updated types for the config changes

Thanks for the update!

> --- a/drivers/pinctrl/renesas/pinctrl-rzg2l.c
> +++ b/drivers/pinctrl/renesas/pinctrl-rzg2l.c
> @@ -78,9 +78,9 @@
>                                          PIN_CFG_FILNUM | \
>                                          PIN_CFG_FILCLKSEL)
>
> -#define PIN_CFG_PIN_MAP_MASK           GENMASK_ULL(35, 28)
> -#define PIN_CFG_PIN_REG_MASK           GENMASK(27, 20)
> -#define PIN_CFG_MASK                   GENMASK(19, 0)
> +#define PIN_CFG_PIN_MAP_MASK           GENMASK_ULL(62, 55)
> +#define PIN_CFG_PIN_REG_MASK           GENMASK_ULL(54, 47)
> +#define PIN_CFG_MASK                   GENMASK_ULL(46, 0)
>
>  /*
>   * m indicates the bitmap of supported pins, a is the register index

> @@ -241,9 +241,9 @@ struct rzg2l_dedicated_configs {
>   * @pin: port pin
>   */
>  struct rzg2l_variable_pin_cfg {
> -       u32 cfg:20;
> -       u32 port:5;
> -       u32 pin:3;
> +       u64 cfg:46;

47, to match PIN_CFG_MASK()?

> +       u64 port:5;
> +       u64 pin:3;
>  };

To avoid such mistakes, and to increase uniformity, I think it would
be good to get rid of this structure, and replace it by masks, to be
used with FIELD_GET() and FIELD_PREP_CONST().

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68korg

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