• Thierry Reding's avatar
    ARM: tegra: Comment out gpio-ranges properties · 4f1d8414
    Thierry Reding authored
    While the addition of these properties is technically correct it unveils
    a bug with deferred probe. The problem is that the presence of the gpio-
    range property causes the gpio-tegra driver to defer probe (it needs the
    pinctrl driver to be ready). That's technically correct, but it causes a
    couple of issues:
    
      - The keyboard on Chromebooks stops working. The reason for that is
        that the gpio-tegra device has not registered an IRQ domain by the
        time the EC SPI device is registered, hence the interrupt number
        resolves to 0. This is technically a bug in the SPI core, since it
        should really resolve the interrupt at probe time and defer if the
        IRQ domain isn't available yet. This is similar to what's done for
        I2C and platform device already.
    
      - The gpio-tegra device deferring probe means that it is moved to the
        end of the dpm_list. This list defines the suspend/resume order for
        devices. However the core lacks a way to move all users of the
        gpio-tegra device to the end of the dpm_list at the same time. This
        in turn results in a subtle bug on Jetson TK1, where the gpio-keys
        device is used to expose the power key as input. The power key is a
        convenient way to wake the system from suspend. Interestingly, the
        gpio-keys device ends up getting probed at a point after gpio-tegra
        has been probed successfully from having been deferred earlier. As
        such the driver doesn't need to defer the probe itself, and hence
        the device isn't moved to the end of the dpm_list. This causes the
        gpio-tegra device to be suspended before gpio-keys, which in turn
        leaves gpio-keys unable to wake the system from suspend.
    
    There are patches in the works to fix both of the above issues, but they
    are too involved to make it into v4.3, so in the meantime let's fix the
    regressions by commenting out the gpio-ranges properties until the fixes
    have landed.
    Signed-off-by: default avatarThierry Reding <treding@nvidia.com>
    Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
    4f1d8414
tegra30.dtsi 25.8 KB