[PATCH 3/7] arm64: dts: qcom: c630: Enable DisplayPort alt mode

[Ard Biesheuvel <ardb+git@google.com>]

From: Ard Biesheuvel <ardb@kernel.org>

The right-hand USB-C port supports DisplayPort alt mode. The EC takes care
of entering it, and ucsi_yoga_c630 already sets the orientation of the
combo PHY and passes the EC's DP hotplug events down the bridge chain. All
that is missing is the DisplayPort controller, which sdm845.dtsi already
connects to the combo PHY.

Limit it to two lanes. That is what the PHY provides alongside USB3 in its
default mode, and it matches pin assignment D, which the EC picked with
the monitor I tested. Four lanes would need the PHY to be switched to its
DP only mode, which nothing does on this platform.

Tested with a USB-C monitor: 1920x1200@60 over two lanes at HBR2, with the
monitor's USB3 hub working at the same time.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/arm64/boot/dts/qcom/sdm850-lenovo-yoga-c630.dts | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/arm64/boot/dts/qcom/sdm850-lenovo-yoga-c630.dts b/arch/arm64/boot/dts/qcom/sdm850-lenovo-yoga-c630.dts
index a4a573ea7e4a..0645ab429177 100644
--- a/arch/arm64/boot/dts/qcom/sdm850-lenovo-yoga-c630.dts
+++ b/arch/arm64/boot/dts/qcom/sdm850-lenovo-yoga-c630.dts
@@ -589,6 +589,14 @@ &mdss {
 	status = "okay";
 };
 
+&mdss_dp {
+	status = "okay";
+};
+
+&mdss_dp_out {
+	data-lanes = <0 1>;
+};
+
 &mdss_dsi0 {
 	status = "okay";
 	vdda-supply = <&vreg_l26a_1p2>;
-- 
2.56.0.611.g1030f0b940-goog