I am using an Analogix SP6001 SlimPort Micro-USB to 4K HDMI Adapter to connect my Nexus 5 phone to an external display. The external display is not fully working yet however I think I'm close. When I plug the cable into the phone, the interrupt for the hot plug detect GPIO for the HDMI bridge (Analogix ANX7808) fires and anx78xx_handle_common_int_4() shows that the interrupt status bit is set to SP_HPD_ESYNC_ERR.
The second hot plug detect pin (for qcom,hdmi-tx-8974 for the MSM KMS/DRM driver) does not fire, and the clocks are not configured via msm_hdmi_phy_pll_init(). I suspect that this is the issue that I need to solve next.
I verified in the downstream MSM sources that IRQ 8 on the mdss is the correct IRQ number for hdmi-tx. Here's the relevant line from /proc/interrupts showing that no interrupts are triggered: 93: 0 0 0 0 mdss 8 Edge hdmi_isr.
I'm going to continue digging through the code but I'd appreciate any suggestions for things to check. I assume that the IRQs for both hot plug detect pins should fire when I plug the cable in. Unfortunately, the display doesn't work for me with the downstream kernel and I only have access to a running downstream kernel over the serial console.
High-level changes since v1: - Hot plug detect interrupt now working properly on HDMI bridge - Introduce msm8974 PLL support
I've held back some cosmetic changes to the drivers and only included the necessary changes required to get this functional. This requires the following patch I sent out on 2019-09-22 to analogix-anx78xx that corrects an i2c address: https://lore.kernel.org/lkml/20190922175940.5311-1-masneyb@onstation.org/
Brian Masney (5): drm/bridge: analogix-anx78xx: add support for avdd33 regulator drm/msm/hdmi: add msm8974 PLL support ARM: dts: qcom: pm8941: add 5vs2 regulator node ARM: dts: qcom: msm8974: add HDMI nodes ARM: dts: qcom: msm8974-hammerhead: add support for external display
.../qcom-msm8974-lge-nexus5-hammerhead.dts | 142 ++++ arch/arm/boot/dts/qcom-msm8974.dtsi | 78 ++ arch/arm/boot/dts/qcom-pm8941.dtsi | 10 + drivers/gpu/drm/bridge/analogix-anx78xx.c | 33 + drivers/gpu/drm/msm/Makefile | 1 + drivers/gpu/drm/msm/hdmi/hdmi.h | 6 + drivers/gpu/drm/msm/hdmi/hdmi_phy.c | 4 +- drivers/gpu/drm/msm/hdmi/hdmi_pll_8974.c | 684 ++++++++++++++++++ 8 files changed, 957 insertions(+), 1 deletion(-) create mode 100644 drivers/gpu/drm/msm/hdmi/hdmi_pll_8974.c