• Martin Blumenstingl's avatar
    ARM64: dts: meson-gxl: add USB host support · 8aec5fc1
    Martin Blumenstingl authored
    This adds USB host support to the Meson GXL SoC. A dwc3 controller is
    used for host-mode, while a dwc2 controller (not added in this patch
    because I could not get it working) is used for device-mode only.
    
    The dwc3 controller's internal roothub has two USB2 ports enabled but no
    USB3 port. Each of the ports is supplied by a separate PHY. The USB pins
    are connected to the SoC's USBHOST_A and USBOTG_B pins.
    Due to the way the roothub works internally the USB PHYs are left
    enabled. When the dwc3 controller is disabled the PHY is never powered on
    so it does not draw any extra power. However, when the dwc3 host
    controller is enabled then all PHYs also have to be enabled, otherwise
    USB devices will not be detected (regardless of whether they are plugged
    into an enabled port or not). This means that only the dwc3 controller
    has to be enabled on boards with USB support (instead of requiring all
    boards to enable the PHYs additionally with the chance of forgetting to
    enable one and breaking all other ports with that as well).
    
    This also adds the USB3 PHY which currently only does some basic
    initialization. That however is required because without it high-speed
    devices (like USB thumb drives) do not work on some devices (probably
    because the bootloader does not configure the USB3 PHY registers).
    Signed-off-by: default avatarMartin Blumenstingl <martin.blumenstingl@googlemail.com>
    Signed-off-by: default avatarKevin Hilman <khilman@baylibre.com>
    8aec5fc1
meson-gxl.dtsi 14.4 KB