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Date:   Tue, 26 Sep 2023 12:55:53 +0300
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Subject: Re: [PATCH 25/37] pinctrl: renesas: rzg2l: adapt function number for
 RZ/G3S
To:     Geert Uytterhoeven <geert@linux-m68k.org>
Cc:     mturquette@baylibre.com, sboyd@kernel.org, robh+dt@kernel.org,
        krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org,
        ulf.hansson@linaro.org, linus.walleij@linaro.org,
        gregkh@linuxfoundation.org, jirislaby@kernel.org,
        magnus.damm@gmail.com, catalin.marinas@arm.com, will@kernel.org,
        prabhakar.mahadev-lad.rj@bp.renesas.com,
        biju.das.jz@bp.renesas.com, quic_bjorande@quicinc.com,
        arnd@arndb.de, konrad.dybcio@linaro.org, neil.armstrong@linaro.org,
        nfraprado@collabora.com, rafal@milecki.pl,
        wsa+renesas@sang-engineering.com,
        linux-renesas-soc@vger.kernel.org, linux-clk@vger.kernel.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-mmc@vger.kernel.org, linux-gpio@vger.kernel.org,
        linux-serial@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
References: <20230912045157.177966-1-claudiu.beznea.uj@bp.renesas.com>
 <20230912045157.177966-26-claudiu.beznea.uj@bp.renesas.com>
 <CAMuHMdVkttQpA-s0MrKbTVxJ6K+xXmhV3sNNLTAPSbDa0f8XYA@mail.gmail.com>
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From:   claudiu beznea <claudiu.beznea@tuxon.dev>
In-Reply-To: <CAMuHMdVkttQpA-s0MrKbTVxJ6K+xXmhV3sNNLTAPSbDa0f8XYA@mail.gmail.com>
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Hi, Geert,

On 21.09.2023 15:51, Geert Uytterhoeven wrote:
> Hi Claudiu,
> 
> Thanks for your patch!
> 
> On Tue, Sep 12, 2023 at 6:53 AM Claudiu <claudiu.beznea@tuxon.dev> wrote:
>> From: Claudiu Beznea <claudiu.beznea.uj@bp.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@bp.renesas.com>
> 
> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.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.

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

Thank you,
Claudiu Beznea

> 
> Gr{oetje,eeting}s,
> 
>                         Geert
> 
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-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