Hi!
This is a very rough cut of support for the MT8173-based Acer Chromebook R13 ("Elm") platform. It mostly consists of drivers ported from the chromeos-3.18 vendor kernel, a little device tree, and a number of hacks.
This is the first iteration that worked well enough to light up the display and provide a framebuffer console, and I haven't looked much into why most of these hacks are necessary yet. The exception is the mmsys device, see "hack: mediatek: get mmsys to register as both DRM and clock device" for details on that.
You can find this series at https://github.com/uli/kernel/tree/elm-working, which also contains a config file and several ancillary bits that are required to build a kernel partition for the Chromebook. Instructions on how to do so (and various other things that have to be done to get it running on your device) are available at https://www.elinux.org/User:Uli/Acer_Chromebook_R13_GPU_test_system (These instructions have been written for the vendor kernel, but apply to mainline as well, except that you won't need any extra patches.)
Testing has so far been limited to what I needed to copy new kernel images to the device: keyboard, LCD, backlight, SD card and USB port work.
CU Uli
Ulrich Hecht (11): soc: mediatek: MediaTek Command Queue (CMDQ) driver drm/bridge: GPIO-controlled display multiplexer driver platform/chrome: ChromeOS firmware interface driver drm/bridge: Parade PS8640 MIPI DSI -> eDP converter driver drm/bridge: Analogix ANX7688 HDMI -> DP bridge driver arm64: dts: mediatek: Add Elm Rev. 3 device tree hack: mediatek: get mmsys to register as both DRM and clock device hack: drm/mediatek: roll back drm_of_find_panel_or_bridge() use drm/mediatek: add fbdev support hack: mtk-sd: use old driver from vendor kernel hack: Revert "iommu/io-pgtable: Sanitise map/unmap addresses"
arch/arm64/boot/dts/mediatek/Makefile | 1 + arch/arm64/boot/dts/mediatek/mt8173-elm-rev3.dts | 21 + arch/arm64/boot/dts/mediatek/mt8173-elm.dtsi | 210 ++ arch/arm64/boot/dts/mediatek/mt8173-oak.dtsi | 1014 ++++++++ drivers/clk/mediatek/clk-mt8173.c | 4 +- drivers/gpu/drm/bridge/Kconfig | 32 + drivers/gpu/drm/bridge/Makefile | 5 + drivers/gpu/drm/bridge/analogix-anx7688.c | 233 ++ drivers/gpu/drm/bridge/generic-gpio-mux.c | 316 +++ drivers/gpu/drm/bridge/parade-ps8640.c | 1104 +++++++++ drivers/gpu/drm/mediatek/Makefile | 2 + drivers/gpu/drm/mediatek/mtk_dpi.c | 5 +- drivers/gpu/drm/mediatek/mtk_drm_ddp.c | 5 +- drivers/gpu/drm/mediatek/mtk_drm_drv.c | 16 + drivers/gpu/drm/mediatek/mtk_drm_drv.h | 4 +- drivers/gpu/drm/mediatek/mtk_drm_fb.c | 13 + drivers/gpu/drm/mediatek/mtk_drm_fb.h | 3 + drivers/gpu/drm/mediatek/mtk_drm_fbdev.c | 184 ++ drivers/gpu/drm/mediatek/mtk_drm_fbdev.h | 32 + drivers/gpu/drm/mediatek/mtk_dsi.c | 21 +- drivers/gpu/drm/mediatek/mtk_hdmi.c | 5 +- drivers/iommu/io-pgtable-arm-v7s.c | 6 - drivers/iommu/io-pgtable-arm.c | 7 - drivers/mmc/host/mtk-sd.c | 465 ++-- drivers/platform/chrome/Kconfig | 18 + drivers/platform/chrome/Makefile | 2 + drivers/platform/chrome/chromeos.c | 120 + drivers/platform/chrome/chromeos.h | 61 + drivers/platform/chrome/chromeos_arm.c | 264 ++ drivers/platform/chrome/elog.h | 186 ++ drivers/soc/mediatek/Kconfig | 10 + drivers/soc/mediatek/Makefile | 1 + drivers/soc/mediatek/mtk-cmdq.c | 2814 ++++++++++++++++++++++ include/linux/chromeos_platform.h | 27 + include/soc/mediatek/cmdq.h | 211 ++ 35 files changed, 7161 insertions(+), 261 deletions(-) create mode 100644 arch/arm64/boot/dts/mediatek/mt8173-elm-rev3.dts create mode 100644 arch/arm64/boot/dts/mediatek/mt8173-elm.dtsi create mode 100644 arch/arm64/boot/dts/mediatek/mt8173-oak.dtsi create mode 100644 drivers/gpu/drm/bridge/analogix-anx7688.c create mode 100644 drivers/gpu/drm/bridge/generic-gpio-mux.c create mode 100644 drivers/gpu/drm/bridge/parade-ps8640.c create mode 100644 drivers/gpu/drm/mediatek/mtk_drm_fbdev.c create mode 100644 drivers/gpu/drm/mediatek/mtk_drm_fbdev.h create mode 100644 drivers/platform/chrome/chromeos.c create mode 100644 drivers/platform/chrome/chromeos.h create mode 100644 drivers/platform/chrome/chromeos_arm.c create mode 100644 drivers/platform/chrome/elog.h create mode 100644 drivers/soc/mediatek/mtk-cmdq.c create mode 100644 include/linux/chromeos_platform.h create mode 100644 include/soc/mediatek/cmdq.h