• H. Nikolaus Schaller's avatar
    DTS: ARM: gta04: introduce legacy spi-cs-high to make display work again · f1f028ff
    H. Nikolaus Schaller authored
    commit 6953c57a "gpio: of: Handle SPI chipselect legacy bindings"
    
    did introduce logic to centrally handle the legacy spi-cs-high property
    in combination with cs-gpios. This assumes that the polarity
    of the CS has to be inverted if spi-cs-high is missing, even
    and especially if non-legacy GPIO_ACTIVE_HIGH is specified.
    
    The DTS for the GTA04 was orginally introduced under the assumption
    that there is no need for spi-cs-high if the gpio is defined with
    proper polarity GPIO_ACTIVE_HIGH.
    
    This was not a problem until gpiolib changed the interpretation of
    GPIO_ACTIVE_HIGH and missing spi-cs-high.
    
    The effect is that the missing spi-cs-high is now interpreted as CS being
    low (despite GPIO_ACTIVE_HIGH) which turns off the SPI interface when the
    panel is to be programmed by the panel driver.
    
    Therefore, we have to add the redundant and legacy spi-cs-high property
    to properly activate CS.
    
    Cc: stable@vger.kernel.org
    Signed-off-by: default avatarH. Nikolaus Schaller <hns@goldelico.com>
    Signed-off-by: default avatarTony Lindgren <tony@atomide.com>
    f1f028ff
omap3-gta04.dtsi 22.6 KB