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@linaro.org
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@vger.kernel.org Signed-off-by: Bartosz Golaszewski bartosz.golaszewski@linaro.org
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@bgdev.pl/
Regards, Antonio