• Thomas Petazzoni's avatar
    gpio: add core support for pull-up/pull-down configuration · d449991c
    Thomas Petazzoni authored
    This commit adds support for configuring the pull-up and pull-down
    resistors available in some GPIO controllers. While configuring
    pull-up/pull-down is already possible through the pinctrl subsystem,
    some GPIO controllers, especially simple ones such as GPIO expanders
    on I2C, don't have any pinmuxing capability and therefore do not use
    the pinctrl subsystem.
    
    This commit implements the GPIO_PULL_UP and GPIO_PULL_DOWN flags,
    which can be used from the Device Tree, to enable a pull-up or
    pull-down resistor on a given GPIO.
    
    The flag is simply propagated all the way to the core GPIO subsystem,
    where it is used to call the gpio_chip ->set_config callback with the
    appropriate existing PIN_CONFIG_BIAS_* values.
    Signed-off-by: default avatarThomas Petazzoni <thomas.petazzoni@bootlin.com>
    Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
    d449991c
gpiolib.c 128 KB