linux-kernel - Re: [PATCH v2 10/13] pinctrl: renesas: pinctrl-rzg2l: Add support to set pulling up/down the pins

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Date: Thu, 30 May 2024 11:37:48 +0100
From: "Lad, Prabhakar" <prabhakar.csengg@...il.com>
To: claudiu beznea <claudiu.beznea@...on.dev>
Cc: Geert Uytterhoeven <geert+renesas@...der.be>, 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 10/13] pinctrl: renesas: pinctrl-rzg2l: Add support to
 set pulling up/down the pins

On Thu, May 30, 2024 at 8:48 AM claudiu beznea <claudiu.beznea@...on.dev> wrote:
>
> Hi, Prabhakar,
>
> On 23.04.2024 20:58, Prabhakar wrote:
> > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> >
> > Add support to configure bias-disable, bias-pull-up and bias-pull-down
> > properties of the pin.
> >
> > Two new function pointers get_bias_param() and get_bias_val() are
> > introduced as the values in PUPD register differ when compared to
> > RZ/G2L family and RZ/V2H(P) SoC,
> >
> > Value | RZ/G2L        | RZ/V2H
> > ---------------------------------
> > 00b:  | Bias Disabled | Pull up/down disabled
> > 01b:  | Pull-up       | Pull up/down disabled
> > 10b:  | Pull-down     | Pull-down
> > 11b:  | Prohibited    | Pull-up
> >
> > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> > ---
> > RFC->v2
> > - New patch
> > ---
> >  drivers/pinctrl/renesas/pinctrl-rzg2l.c | 73 +++++++++++++++++++++++++
> >  1 file changed, 73 insertions(+)
> >
> > diff --git a/drivers/pinctrl/renesas/pinctrl-rzg2l.c b/drivers/pinctrl/renesas/pinctrl-rzg2l.c
> > index 102fa75c71d3..c144bf43522b 100644
> > --- a/drivers/pinctrl/renesas/pinctrl-rzg2l.c
> > +++ b/drivers/pinctrl/renesas/pinctrl-rzg2l.c
> > @@ -122,6 +122,7 @@
> >  #define IOLH(off)            (0x1000 + (off) * 8)
> >  #define SR(off)                      (0x1400 + (off) * 8)
> >  #define IEN(off)             (0x1800 + (off) * 8)
> > +#define PUPD(off)            (0x1C00 + (off) * 8)
> >  #define ISEL(off)            (0x2C00 + (off) * 8)
> >  #define SD_CH(off, ch)               ((off) + (ch) * 4)
> >  #define ETH_POC(off, ch)     ((off) + (ch) * 4)
> > @@ -140,6 +141,7 @@
> >  #define IEN_MASK             0x01
> >  #define IOLH_MASK            0x03
> >  #define SR_MASK                      0x01
> > +#define PUPD_MASK            0x03
> >
> >  #define PM_INPUT             0x1
> >  #define PM_OUTPUT            0x2
> > @@ -265,6 +267,8 @@ struct rzg2l_pinctrl_data {
> >       void (*pmc_writeb)(struct rzg2l_pinctrl *pctrl, u8 val, void __iomem *addr);
> >       u32 (*read_oen)(struct rzg2l_pinctrl *pctrl, u32 caps, u32 offset, u8 pin);
> >       int (*write_oen)(struct rzg2l_pinctrl *pctrl, u32 caps, u32 offset, u8 pin, u8 oen);
> > +     int (*get_bias_param)(u8 val);
> > +     int (*get_bias_val)(enum pin_config_param param);
> >  };
> >
> >  /**
> > @@ -1081,6 +1085,38 @@ static int rzg2l_write_oen(struct rzg2l_pinctrl *pctrl, u32 caps, u32 offset, u8
> >       return 0;
> >  }
> >
> > +static int rzg2l_get_bias_param(u8 val)
> > +{
> > +     switch (val) {
> > +     case 0:
> > +             return PIN_CONFIG_BIAS_DISABLE;
> > +     case 1:
> > +             return PIN_CONFIG_BIAS_PULL_UP;
> > +     case 2:
> > +             return PIN_CONFIG_BIAS_PULL_DOWN;
> > +     default:
> > +             break;
> > +     }
> > +
> > +     return -EINVAL;
> > +}
> > +
> > +static int rzg2l_get_bias_val(enum pin_config_param param)
> > +{
> > +     switch (param) {
> > +     case PIN_CONFIG_BIAS_DISABLE:
> > +             return 0;
> > +     case PIN_CONFIG_BIAS_PULL_UP:
> > +             return 1;
> > +     case PIN_CONFIG_BIAS_PULL_DOWN:
> > +             return 2;
> > +     default:
> > +             break;
> > +     }
> > +
> > +     return -EINVAL;
> > +}
> > +
> >  static int rzg2l_pinctrl_pinconf_get(struct pinctrl_dev *pctldev,
> >                                    unsigned int _pin,
> >                                    unsigned long *config)
> > @@ -1139,6 +1175,25 @@ static int rzg2l_pinctrl_pinconf_get(struct pinctrl_dev *pctldev,
> >               arg = rzg2l_read_pin_config(pctrl, SR(off), bit, SR_MASK);
> >               break;
> >
> > +     case PIN_CONFIG_BIAS_DISABLE:
> > +     case PIN_CONFIG_BIAS_PULL_UP:
> > +     case PIN_CONFIG_BIAS_PULL_DOWN: {
>
> Block { } can be removed here.
>
> > +             if (!(cfg & PIN_CFG_PUPD))
> > +                     return -EINVAL;
> > +
> > +             ret = pctrl->data->get_bias_param(rzg2l_read_pin_config(pctrl,
> > +                                                                     PUPD(off),
> > +                                                                     bit, PUPD_MASK));
> > +             if (ret < 0)
> > +                     return ret;
> > +
> > +             if (ret != param)
> > +                     return -EINVAL;
>
> Can this happen? Otherwise it can be removed.
>
Yes this can happen (and is needed) as we want to report only the
current BIAS setting of the pin.

For example without this condition I get the below for ET1_RXD3 pin:
pin 173 (ET1_RXD3): input bias disabled, input bias pull down (0x1
ohms), input bias pull up (0x1 ohms)
with the check included:
pin 173 (ET1_RXD3): input bias disabled

Cheers,
Prabhakar