This series adds a driver for the USB2 PHYs found in Amlogic Meson GXL (and GXM) SoCs. Devicetree changes are intentionally missing in this series because of various other problems that need to be resolved before we get USB host support working. As usual we unfortunately don't have any documentation available. The register definitions were taken from the vendor's GPL kernel sources (see [5] if you are really interested). Translation to human readable names is done using the "best effort" algorithm. The USB situation on GXL and GXM is a bit special: the SoCs include both, a dwc3 and a dwc2 controller. The dwc3 controller IP only supports host-mode, while the dwc2 controller IP only supports device mode. The dwc3 controller has all USB3 ports disabled. GXL has two USB2 ports enabled on dwc3's internal hub, while GXM has three USB2 ports enabled. This makes the initialization a bit special: to enable any of the dwc3 controller's USB2 ports *ALL* PHYs have to be initialized (probably due to the hub's routing logic). The first USB2 PHY (hardware-wise) also supports OTG mode. The vendor kernel implements this through the USB3 PHY by re-routing the first USB2 PHY from the dwc3 controller to the dwc2 controller (which is disabled by default, but if the USB3 PHY detects that the port should enter device mode it enables the dwc2 controller). To get USB host mode working the following steps are needed: - xhci-plat must be able to manage more than one PHY for a controller, this is work-in-progress, see [0] - there are some DMA handling issues in dwc3 and the rest of the USB stack, this is solved by the "sysdev" patches from [1] - adding all USB related bits to meson-gxl.dtsi - this is work in progress but depends on the previous TODOs, see [2] and [3] This supersedes my previous series "Meson GXL and GXM USB support" [4]. [0] https://www.spinics.net/lists/linux-usb/msg151837.html [1] http://www.mail-archive.com/linux-usb@xxxxxxxxxxxxxxx/msg87077.html [2] https://github.com/xdarklight/linux/commit/e2b83785687fe859ae4bba8da8bb2fb2d7e32bfb [3] https://github.com/xdarklight/linux/commit/203ab9ea5d1bea0bf066b6738010c8072b821d87 [4] http://lists.infradead.org/pipermail/linux-amlogic/2016-November/001721.html [5] https://github.com/khadas/linux/blob/76fd19ac41bb774e396ce8009ff665f29c26c535/include/linux/amlogic/usb-gxl.h Martin Blumenstingl (2): Documentation: dt-bindings: Add documentation for the Meson GXL USB2 PHY phy: meson: add USB2 PHY support for Meson GXL and GXM .../devicetree/bindings/phy/meson-gxl-usb2-phy.txt | 17 ++ drivers/phy/Kconfig | 13 + drivers/phy/Makefile | 1 + drivers/phy/phy-meson-gxl-usb2.c | 263 +++++++++++++++++++++ 4 files changed, 294 insertions(+) create mode 100644 Documentation/devicetree/bindings/phy/meson-gxl-usb2-phy.txt create mode 100644 drivers/phy/phy-meson-gxl-usb2.c -- 2.12.0 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
