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

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Date:   Tue, 26 Sep 2023 16:23:41 +0200
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     claudiu beznea <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,

On Tue, Sep 26, 2023 at 11:55 AM claudiu beznea
<claudiu.beznea@...on.dev> wrote:
> On 21.09.2023 15:51, Geert Uytterhoeven wrote:
> > 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.
>
> Yes, I'll mention it like this in the next version.
>
> >> 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).
>
> I'll have a look on this. I see .set_mux() can also be called from sysfs
> though pinmux-select exported file thus, I don't know at the moment if
> validating it on rzg2l_dt_subnode_to_map() will be enough.

OK, that's a good reason to keep it as-is.

> Would it be OK to have this outside of this series or you would prefer it now?

That can be done later. I believe currently there is no validation against
the register field size limit anyway.
Thanks!

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