[PATCH] arm: gpio: Add set_flags callback to the Tegra gpio driver

[Svyatoslav Ryhel]

пн, 22 вер. 2025 р. о 11:08 Łukasz Majewski <lukma at nabladev.com> пише:
>
> Hi Svyatoslav,
>
> > пт, 19 вер. 2025 р. о 13:11 Lukasz Majewski <lukma at nabladev.com> пише:
> > >
> > > In some Tegra SoC (like e.g. T30) there is a possibility that one
> > > will configure at early boot state a pin as GPIO (to use it for
> > > e.g. carrier board detection). However, afterwards (i.e. in Linux)
> > > the same pin will be used as the special function one.
> > >
> > > Current Tegra gpio driver doesn't allow this, so callback for
> > > set_flags() has been defined to properly setup the GPIO when
> > > required.
> >
> > Please write the commit message in the imperative mood.
> >
> > > For now following flags are supported:
> > > - GPIOD_IS_AF (i.e. "alternate function").
> > > - GPIOD_IS_IN
> > > - GPIOD_IS_OUT
> > >
> > > In long term the tegra_gpio_set_flags() is going to replace
> > > direction_{input|output} callbacks.
> > >
> >
> > It is not a book chapter, describe what the commit does briefly.
>
> Sorry, but the commit message is a pretty nice form of the
> documentation.
>
> For example when you come back to a project, after a few years each
> extra sentence is priceless.
>
> >
> > > Signed-off-by: Lukasz Majewski <lukma at nabladev.com>
> > > ---
> > >  drivers/gpio/tegra_gpio.c | 24 ++++++++++++++++++++++++
> > >  1 file changed, 24 insertions(+)
> > >
> > > diff --git a/drivers/gpio/tegra_gpio.c b/drivers/gpio/tegra_gpio.c
> > > index 3d1e18854f2..1e8bd051875 100644
> > > --- a/drivers/gpio/tegra_gpio.c
> > > +++ b/drivers/gpio/tegra_gpio.c
> > > @@ -258,6 +258,29 @@ static int tegra_gpio_rfree(struct udevice
> > > *dev, unsigned int offset) return 0;
> > >  }
> > >
> > > +static int tegra_gpio_set_flags(struct udevice *dev, unsigned int
> > > offset,
> > > +                               ulong flags)
> > > +{
> > > +       struct tegra_port_info *state = dev_get_priv(dev);
> > > +       int gpio = state->base_gpio + offset;
> > > +
> > > +       debug("gpio_set_flags: pin = %d (port %d:bit %d), flag =
> > > %d\n",
> > > +             gpio, GPIO_FULLPORT(gpio), GPIO_BIT(gpio), flags);
> > > +
> >
> > Have you even built this code yourself? "flags" is of type ulong, not
> > int
>
> It was compiling, but I will double check it.
>
> >
> > > +       if (flags & GPIOD_IS_AF) {
> > > +               set_config(gpio, CFG_SFIO);
> > > +               return 0;
> > > +       } else if (flags & GPIOD_IS_IN) {
> > > +               return tegra_gpio_direction_input(dev, offset);
> > > +       } else if (flags & GPIOD_IS_OUT) {
> > > +               bool value = flags & GPIOD_IS_OUT_ACTIVE;
> > > +
> > > +               return tegra_gpio_direction_output(dev, offset,
> > > value);
> > > +       }
> > > +
> > > +       return -EINVAL;
> > > +}
> > > +
> > >  static const struct dm_gpio_ops gpio_tegra_ops = {
> > >         .direction_input        = tegra_gpio_direction_input,
> > >         .direction_output       = tegra_gpio_direction_output,
> > > @@ -266,6 +289,7 @@ static const struct dm_gpio_ops gpio_tegra_ops
> > > = { .get_function           = tegra_gpio_get_function,
> > >         .xlate                  = tegra_gpio_xlate,
> > >         .rfree                  = tegra_gpio_rfree,
> > > +       .set_flags              = tegra_gpio_set_flags,
> >
> > If you are already touching this anyway, then touch it properly. Since
> > set_flags op is meant to remove direction ops, then remove latter too.
> >
>
> Ok.
>
> > >  };
> > >
> > >  /*
> > > --
> > > 2.39.5
> > >
> >
> > This commit causes regression on LG P990 board, backlight is located
> > on gpio i2c line and with this patch gpio i2c refuses to work
> >
> > (bootloader) Core:  114 devices, 27 uclasses, devicetree: separate
> > (bootloader) MMC:   sdhci at c8000400: 1, sdhci at c8000600: 0
> > (bootloader) Loading Environment from MMC... Reading from MMC(0)...
> > *** (bootloader) Warning - bad CRC, using default environment
> > (bootloader)
> > (bootloader) Can't get i2c-5 gpios! Error: -22
> > (bootloader) Can't get i2c-5 gpios! Error: -16
> > (bootloader) In:    serial,usbkbd,button-kbd
> > (bootloader) Out:   serial,vidconsole
> > (bootloader) Err:   serial,vidconsole
> > (bootloader) Net:   No ethernet found.
> > (bootloader)
> > (bootloader) Autoboot in 0 seconds
>
> Apparently, some flags are not yet supported - like  GPIOD_PULL_UP/DOWN
> or GPIOD_OPEN_DRAIN.
>
> Is this the one from u-boot/board/lg/star/star.c function
> star_fix_panel()?
>
> Or is it somewhere else - for example in drivers/i2c/i2c-gpio.c ?
>

I have told that it comes from i2c-gpio

> For the latter it looks like I do support all the required flags.
>
> At least on my Colibri T30 it works correctly - so extra help is
> appreciated.
>
> --
> Best regards,
>
> Lukasz Majewski
>
> --
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