linux-kernel - Re: [PATCH v2 3/5] pinctrl: renesas: pinctrl-rzg2l: Add support to get/set pin config for GPIO port pins

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Message-ID: <CA+V-a8u0CMhoYJB8buZugG4Kd4BEkviv_WpBTgmJr6y2+gb-sg@mail.gmail.com>
Date:   Tue, 9 Nov 2021 15:24:48 +0000
From:   "Lad, Prabhakar" <prabhakar.csengg@...il.com>
To:     Geert Uytterhoeven <geert@...ux-m68k.org>
Cc:     Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux-Renesas <linux-renesas-soc@...r.kernel.org>,
        Biju Das <biju.das.jz@...renesas.com>
Subject: Re: [PATCH v2 3/5] pinctrl: renesas: pinctrl-rzg2l: Add support to
 get/set pin config for GPIO port pins

Hi Geert,

On Tue, Nov 9, 2021 at 3:00 PM Geert Uytterhoeven <geert@...ux-m68k.org> wrote:
>
> Hi Prabhakar,
>
> On Tue, Nov 9, 2021 at 3:31 PM Lad, Prabhakar
> <prabhakar.csengg@...il.com> wrote:
> > On Mon, Nov 8, 2021 at 3:36 PM Geert Uytterhoeven <geert@...ux-m68k.org> wrote:
> > > On Fri, Oct 29, 2021 at 2:44 PM Lad Prabhakar
> > > <prabhakar.mahadev-lad.rj@...renesas.com> wrote:
> > > > Add support to get/set pin config for GPIO port pins.
> > > >
> > > > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> > > > Reviewed-by: Biju Das <biju.das.jz@...renesas.com>
> > >
> > > Thanks for your patch!
> > >
> > > > --- a/drivers/pinctrl/renesas/pinctrl-rzg2l.c
> > > > +++ b/drivers/pinctrl/renesas/pinctrl-rzg2l.c
> > >
> > > > @@ -495,6 +512,14 @@ static int rzg2l_pinctrl_pinconf_get(struct pinctrl_dev *pctldev,
> > > >                 port = RZG2L_SINGLE_PIN_GET_PORT(*pin_data);
> > > >                 cfg = RZG2L_SINGLE_PIN_GET_CFGS(*pin_data);
> > > >                 bit = RZG2L_SINGLE_PIN_GET_BIT(*pin_data);
> > > > +       } else {
> > > > +               cfg = RZG2L_GPIO_PORT_GET_CFGS(*pin_data);
> > > > +               port = RZG2L_PIN_ID_TO_PORT(_pin);
> > > > +               bit = RZG2L_PIN_ID_TO_PIN(_pin);
> > > > +               port_pin = true;
> > >
> > > Instead of setting this flag, perhaps port should be adjusted?
> >
> > Something like below?
> >
> > #define RZG2L_PORT_START_OFFSET 0x10
> >
> > port = RZG2L_PIN_ID_TO_PORT_pin) + RZG2L_PORT_START_OFFSET;
> > rzg2l_validate_gpio_pin(pctrl, *pin_data, port - RZG2L_PORT_START_OFFSET, bit)
>
> Or adjust port after the call to rzg2l_validate_gpio_pin(), to avoid adding
> the offset first, and subtracting it again for calling the latter?
>
> > and rename port -> port_offset in rzg2l_pinctrl_pinconf_get/set
>
> That makes sense.  Currently "port" has two meanings: it can mean
> either the GPIO port index, or the global register index covering both
> single function pin groups and GPIO port indices.
> RZG2L_SINGLE_PIN_GET_PORT() returns the latter.
> RZG2L_PIN_ID_TO_PORT() returns the former, thus needing an extra offset
> to convert to the global register index.
>
for symmetry will rename the below:
RZG2L_SINGLE_PIN_GET_PORT -> RZG2L_SINGLE_PIN_GET_PORT_OFFSET

Introduce a new macros:
#define RZG2L_PORT_START_OFFSET 0x10
#define RZG2L_PIN_ID_TO_PORT_OFFSET(id) (((id) / RZG2L_PINS_PER_PORT)
+ RZG2L_PORT_START_OFFSET)

And use the above two in rzg2l_pinctrl_pinconf_get/set along with
renaming  port -> port_offset

And for rzg2l_validate_gpio_pin() will use below instead:
rzg2l_validate_gpio_pin(pctrl, *pin_data, RZG2L_PIN_ID_TO_PORT(_pin), bit);

> > Or
> > would you prefer to change the RZG2L_PIN_ID_TO_PORT macro and adjust
> > the entire file?
>
> Changing RZG2L_PIN_ID_TO_PORT() would imply changing all macros
> accessing GPIO registers, and is thus quite intrusive.
>
Agreed, I will drop this option.

Cheers,
Prabhakar
> > > Then rzg2l_r{ead,mw}_pin_config() don't have to care about that
> > > anymore.
> > >
> > Agreed.
>
> 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