Re: [PATCH 1/1] pinctrl: sunxi: add GPIO get_direction callback

[James Hilliard]

On Tue, Feb 10, 2026 at 8:49 PM Chen-Yu Tsai <wens@xxxxxxxxxx> wrote:
>
> On Wed, Feb 11, 2026 at 11:33 AM James Hilliard
> <james.hilliard1@xxxxxxxxx> wrote:
>
> Ah, you beat me to it.
>
> > Implement sunxi_pinctrl_gpio_get_direction() and wire it into
> > the sunxi gpio_chip setup.
>
> Can you also mention that without this, calls to gpiochip_get_direction()
> cause a big warning?

Yeah, this was mostly just to silence that warning(I don't think I actually
was actually using the functionality).

> > The new callback reads the pin mux register and compares the mux
> > value against the pin descriptor gpio_in and gpio_out functions
> > to report GPIO_LINE_DIRECTION_IN or GPIO_LINE_DIRECTION_OUT.
> > If the pin is muxed to irq, report it as input.
> >
> > Signed-off-by: James Hilliard <james.hilliard1@xxxxxxxxx>
> > ---
> >  drivers/pinctrl/sunxi/pinctrl-sunxi.c | 32 +++++++++++++++++++++++++++
> >  1 file changed, 32 insertions(+)
> >
> > diff --git a/drivers/pinctrl/sunxi/pinctrl-sunxi.c b/drivers/pinctrl/sunxi/pinctrl-sunxi.c
> > index 0fb057a07dcc..424f23be27b2 100644
> > --- a/drivers/pinctrl/sunxi/pinctrl-sunxi.c
> > +++ b/drivers/pinctrl/sunxi/pinctrl-sunxi.c
> > @@ -995,6 +995,37 @@ static int sunxi_pinctrl_gpio_direction_output(struct gpio_chip *chip,
> >                                             chip->base + offset, false);
> >  }
> >
> > +static int sunxi_pinctrl_gpio_get_direction(struct gpio_chip *chip,
> > +                                           unsigned int offset)
> > +{
> > +       struct sunxi_pinctrl *pctl = gpiochip_get_data(chip);
> > +       struct sunxi_desc_function *in, *out, *irq;
> > +       u32 reg, shift, mask, val;
> > +       u16 pin = chip->base + offset;
> > +
> > +       in = sunxi_pinctrl_desc_find_function_by_pin(pctl, pin, "gpio_in");
> > +       out = sunxi_pinctrl_desc_find_function_by_pin(pctl, pin, "gpio_out");
> > +       if (!in || !out)
> > +               return -EINVAL;
> > +
> > +       irq = sunxi_pinctrl_desc_find_function_by_pin(pctl, pin, "irq");
>
> This is less efficient, as you end up (linearly) searching the whole pin
> array three times.
>
> What I did in my version was implement a search based on pin and muxval.
> I can send that out if it's OK with you.

If you have a better patch I'll just use that instead of sending
a follow up.

>
>
> ChenYu
>
> > +
> > +       sunxi_mux_reg(pctl, offset, &reg, &shift, &mask);
> > +       val = (readl(pctl->membase + reg) & mask) >> shift;
> > +
> > +       if (val == in->muxval)
> > +               return GPIO_LINE_DIRECTION_IN;
> > +
> > +       if (val == out->muxval)
> > +               return GPIO_LINE_DIRECTION_OUT;
> > +
> > +       /* IRQ function is effectively input. */
> > +       if (irq && val == irq->muxval)
> > +               return GPIO_LINE_DIRECTION_IN;
> > +
> > +       return -EINVAL;
> > +}
> > +
> >  static int sunxi_pinctrl_gpio_of_xlate(struct gpio_chip *gc,
> >                                 const struct of_phandle_args *gpiospec,
> >                                 u32 *flags)
> > @@ -1603,6 +1634,7 @@ int sunxi_pinctrl_init_with_flags(struct platform_device *pdev,
> >         pctl->chip->set_config = gpiochip_generic_config;
> >         pctl->chip->direction_input = sunxi_pinctrl_gpio_direction_input;
> >         pctl->chip->direction_output = sunxi_pinctrl_gpio_direction_output;
> > +       pctl->chip->get_direction = sunxi_pinctrl_gpio_get_direction;
> >         pctl->chip->get = sunxi_pinctrl_gpio_get;
> >         pctl->chip->set = sunxi_pinctrl_gpio_set;
> >         pctl->chip->of_xlate = sunxi_pinctrl_gpio_of_xlate;
> > --
> > 2.43.0
> >