• Russell King's avatar
    gpio: add generic single-register fixed-direction GPIO driver · 380639c7
    Russell King authored
    Add a simple, generic, single register fixed-direction GPIO driver.
    This is able to support a single register with a mixture of inputs
    and outputs.
    
    This is different from gpio-mmio and gpio-74xx-mmio:
    * gpio-mmio doesn't allow a fixed direction, it assumes there is always
      a direction register.
    * gpio-74xx-mmio only supports all-in or all-out setups
    * gpio-74xx-mmio is DT only, this needs to support legacy too
    * they don't double-read when getting the GPIO value, as required by
      some implementations that this driver supports
    * we need to always do 32-bit reads, which bgpio doesn't guarantee
    * the current output state may not be readable from the hardware
      register - reading may reflect input status but not output status.
    Signed-off-by: default avatarRussell King <rmk+kernel@armlinux.org.uk>
    Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
    380639c7
Kconfig 35.4 KB