On Wed, 2025-02-19 at 09:38 +0100, Marek Szyprowski wrote:
> Hi Bartosz,
>
> On 10.02.2025 11:51, Bartosz Golaszewski wrote:
> > From: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
> >
> > As per the API contract - gpio_chip::get_direction() may fail and return
> > a negative error number. However, we treat it as if it always returned 0
> > or 1. Check the return value of the callback and propagate the error
> > number up the stack.
> >
> > Cc: stable@xxxxxxxxxxxxxxx
> > Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
> > ---
> > drivers/gpio/gpiolib.c | 44 +++++++++++++++++++++++++++++---------------
> > 1 file changed, 29 insertions(+), 15 deletions(-)
> >
> > diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> > index 679ed764cb14..5d3774dc748b 100644
> > --- a/drivers/gpio/gpiolib.c
> > +++ b/drivers/gpio/gpiolib.c
> > @@ -1057,8 +1057,11 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
> > desc->gdev = gdev;
> >
> > if (gc->get_direction && gpiochip_line_is_valid(gc, desc_index)) {
> > - assign_bit(FLAG_IS_OUT,
> > - &desc->flags, !gc->get_direction(gc, desc_index));
> > + ret = gc->get_direction(gc, desc_index);
> > + if (ret < 0)
> > + goto err_cleanup_desc_srcu;
> > +
> > + assign_bit(FLAG_IS_OUT, &desc->flags, !ret);
> > } else {
> > assign_bit(FLAG_IS_OUT,
> > &desc->flags, !gc->direction_input);
>
> This change breaks bcm2835 pincontrol/gpio driver (and probably others)
> in next-20250218. The problem is that some gpio lines are initially
> configured as alternate function (i.e. uart) and .get_direction returns
> -EINVAL for them, what in turn causes the whole gpio chip fail to
> register. Here is the log with WARN_ON() added to line
> drivers/pinctrl/bcm/pinctrl-bcm2835.c:350 from Raspberry Pi 4B:
Same issue with STM32 pinctrl.
I will send out shortly a patch, similar to
https://lore.kernel.org/all/20250219102750.38519-1-brgl@xxxxxxxx/
Regards,
Antonio
