linux-kernel - Re: [PATCH 25/37] pinctrl: renesas: rzg2l: adapt function number for RZ/G3S

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Message-ID: <CAMuHMdVkttQpA-s0MrKbTVxJ6K+xXmhV3sNNLTAPSbDa0f8XYA@mail.gmail.com>
Date:   Thu, 21 Sep 2023 14:51:11 +0200
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Claudiu <claudiu.beznea@...on.dev>
Cc:     mturquette@...libre.com, sboyd@...nel.org, robh+dt@...nel.org,
        krzysztof.kozlowski+dt@...aro.org, conor+dt@...nel.org,
        ulf.hansson@...aro.org, linus.walleij@...aro.org,
        gregkh@...uxfoundation.org, jirislaby@...nel.org,
        magnus.damm@...il.com, catalin.marinas@....com, will@...nel.org,
        prabhakar.mahadev-lad.rj@...renesas.com,
        biju.das.jz@...renesas.com, quic_bjorande@...cinc.com,
        arnd@...db.de, konrad.dybcio@...aro.org, neil.armstrong@...aro.org,
        nfraprado@...labora.com, rafal@...ecki.pl,
        wsa+renesas@...g-engineering.com,
        linux-renesas-soc@...r.kernel.org, linux-clk@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-mmc@...r.kernel.org, linux-gpio@...r.kernel.org,
        linux-serial@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
Subject: Re: [PATCH 25/37] pinctrl: renesas: rzg2l: adapt function number for RZ/G3S

Hi Claudiu,

Thanks for your patch!

On Tue, Sep 12, 2023 at 6:53 AM Claudiu <claudiu.beznea@...on.dev> wrote:
> From: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
>
> On RZ/G3S PFC register allow setting 8 functions for individual ports
> (function1 to function8). For function1 register need to be configured
> with 0, for function8 register need to be configured with 7.
> We cannot use zero based addressing when requesting functions from
> different code places as documentation (RZG3S_pinfunction_List_r1.0.xlsx)
> states explicitly that function0 has different meaning.

According to that table, function0 is GPIO.

> For this add a new member to struct rzg2l_hwcfg that will keep the
> offset that need to be substracted before applying a value to PFC register.
>
> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>

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

But one question below...

> --- a/drivers/pinctrl/renesas/pinctrl-rzg2l.c
> +++ b/drivers/pinctrl/renesas/pinctrl-rzg2l.c
> @@ -136,9 +136,11 @@ struct rzg2l_register_offsets {
>  /**
>   * struct rzg2l_hwcfg - hardware configuration data structure
>   * @regs: hardware specific register offsets
> + * @func_base: base number for port function (see register PFC)
>   */
>  struct rzg2l_hwcfg {
>         const struct rzg2l_register_offsets regs;
> +       u8 func_base;
>  };
>
>  struct rzg2l_dedicated_configs {
> @@ -221,6 +223,7 @@ static int rzg2l_pinctrl_set_mux(struct pinctrl_dev *pctldev,
>                                  unsigned int group_selector)
>  {
>         struct rzg2l_pinctrl *pctrl = pinctrl_dev_get_drvdata(pctldev);
> +       const struct rzg2l_hwcfg *hwcfg = pctrl->data->hwcfg;
>         const struct pinctrl_pin_desc *pin_desc;
>         unsigned int i, *psel_val, *pin_data;
>         struct function_desc *func;
> @@ -247,9 +250,9 @@ static int rzg2l_pinctrl_set_mux(struct pinctrl_dev *pctldev,
>                 off = RZG2L_PIN_CFG_TO_PORT_OFFSET(*pin_data);
>
>                 dev_dbg(pctrl->dev, "port:%u pin: %u off:%x PSEL:%u\n", port,
> -                       pin, off, psel_val[i]);
> +                       pin, off, psel_val[i] - hwcfg->func_base);
>
> -               rzg2l_pinctrl_set_pfc_mode(pctrl, pin, off, psel_val[i]);
> +               rzg2l_pinctrl_set_pfc_mode(pctrl, pin, off, psel_val[i] - hwcfg->func_base);
>         }
>
>         return 0;

Perhaps the adjustment should be done in rzg2l_dt_subnode_to_map()
instead, when obtaining MUX_FUNC() from DT? That would allow you to do
some basic validation on it too, which is currently completely missing
(reject out-of-range values overflowing into adjacent PFC fields,
reject zero on RZ/G3S).

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