The gpio core looks at 'FLAG_BIAS_DISABLE' in preparation of calling the gpiochip 'set_config()' hook. However, AFAICT, there's no way that this flag is set because there's no support for it in firwmare code. Moreover, in 'gpiod_configure_flags()', only pull-ups and pull-downs are being handled. On top of this, there are some users that are looking at 'PIN_CONFIG_BIAS_DISABLE' in the 'set_config()' hook. So, unless I'm missing something, it looks like this was never working for these chips. Note that the ACPI case is only compiled tested. At first glance, it seems the current patch is enough but i'm not really sure... As a side note, this came to my attention during this patchset [1] (and, ofr OF, was tested with it). [1]: https://lore.kernel.org/linux-input/20220708093448.42617-5-nuno.sa@xxxxxxxxxx/ Nuno Sá (4): gpiolib: add support for bias pull disable gpiolib: of: support bias pull disable gpiolib: acpi: support bias pull disable dt-bindings: gpio: add pull-disable flag drivers/gpio/gpiolib-acpi.c | 3 +++ drivers/gpio/gpiolib-of.c | 7 +++++++ drivers/gpio/gpiolib.c | 8 ++++++-- include/dt-bindings/gpio/gpio.h | 3 +++ include/linux/gpio/machine.h | 1 + include/linux/of_gpio.h | 1 + 6 files changed, 21 insertions(+), 2 deletions(-) -- 2.37.0
