gpiolib: add get_config() and gpiochip_generic_get_config()

A chip with a pin control backend sets a line's configuration through
set_config() and gpiochip_generic_config(), but has no way to read one
back. gpio-mmio needs that to learn the direction of a line whose
direction lives in the pin controller.

Add the optional get_config() callback, taking the packed parameter to
query and returning its bare argument the way pinctrl_gpio_get_config()
does, and gpiochip_generic_get_config() as the pin control backed
implementation, the mirror of gpiochip_generic_config(): a chip without
pin ranges, or a kernel without pinctrl, gets -ENOTSUPP.

Nothing in gpiolib calls get_config() and there is no consumer API; it
is for the chip's own use.

Suggested-by: Linus Walleij <linusw@kernel.org>
Signed-off-by: Mehmet Fide <mehmet.fide@screeningeagle.com>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Link: https://patch.msgid.link/20260915080501.329424-4-mehmet.fide@gmail.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>

0 files changed, 0 insertions, 0 deletions