[PATCH 0/3] drm/bridge: Add Lontium LT8711UXD DP-to-HDMI transparent bridge

[PATCH 0/3] drm/bridge: Add Lontium LT8711UXD DP-to-HDMI transparent bridge

[Dennis Gilmore]

The Lontium LT8711UXD supports two modes of operation: autonomous mode,
where it configures itself via strapping resistors, and I2C-controlled
mode. Review of the earlier Orange Pi 5 Pro series raised the question
of how a future board requiring I2C control should be handled, a second
compatible with a driver or we make both work with a single compatible

This patch set covers autonomous mode only. On the Orange Pi 5 Pro,
resistors R9, R17, and R27 are unpopulated, which straps MODE_SEL low
leaving the device invisible on the I2C bus; I2C control is not enabled
on this board.

The earlier review thread is at:
https://lore.kernel.org/linux-devicetree/20260425031011.2529364-4-dennis@ausil.us/

One non-obvious detail in the DTS patch: vcc3v3_dp carries
regulator-always-on because simple-bridge only fires pre_enable once a
modeset starts, but no modeset will start until the connector reports
connected, and the connector won't report connected until HPD asserts,
and HPD won't assert until the bridge is powered. Holding the enable
line high from boot breaks this deadlock.

Tested on Orange Pi 5 Pro with Linux 7.0: HPD asserts, EDID reads,
link trains, and scanout reaches the display.

Please take a look.

Thank you,

Dennis Gilmore

Dennis Gilmore (3):
  dt-bindings: display: bridge: simple: document the Lontium LT8711UXD
    DP-to-HDMI bridge
  drm/bridge: simple: Add the Lontium LT8711UXD DP-to-HDMI bridge
  arm64: dts: rockchip: orangepi-5-pro: Add LT8711UXD DP-to-HDMI bridge

 .../display/bridge/simple-bridge.yaml         |  1 +
 .../dts/rockchip/rk3588s-orangepi-5-pro.dts   | 88 ++++++++++++++++++-
 drivers/gpu/drm/bridge/simple-bridge.c        |  5 ++
 3 files changed, 91 insertions(+), 3 deletions(-)

-- 
2.54.0

[PATCH 1/3] dt-bindings: display: bridge: simple: document the Lontium LT8711UXD DP-to-HDMI bridge

[Dennis Gilmore]

The Lontium LT8711UXD is a high performance two lane Type-C/DP1.4
to HDMI2.0 converter, designed to connect a USB Type-C source or a DP1.4
source to an HDMI2.0 sink. The device can be running uncontrolled or it
can be attached over I2C, the bindings describe the uncontrolled mode.

Signed-off-by: Dennis Gilmore <dennis@ausil.us>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
---
 .../devicetree/bindings/display/bridge/simple-bridge.yaml        | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Documentation/devicetree/bindings/display/bridge/simple-bridge.yaml b/Documentation/devicetree/bindings/display/bridge/simple-bridge.yaml
index e6808419f625..752c736c8f85 100644
--- a/Documentation/devicetree/bindings/display/bridge/simple-bridge.yaml
+++ b/Documentation/devicetree/bindings/display/bridge/simple-bridge.yaml
@@ -30,6 +30,7 @@ properties:
           - algoltek,ag6311
           - asl-tek,cs5263
           - dumb-vga-dac
+          - lontium,lt8711uxd
           - parade,ps185hdm
           - radxa,ra620
           - realtek,rtd2171
-- 
2.54.0

Claude review: dt-bindings: display: bridge: simple: document the Lontium LT8711UXD DP-to-HDMI bridge

[Claude Code Review Bot]

Patch Review

**No issues.** This adds a single compatible string entry to the simple-bridge binding in the correct alphabetical position:

```yaml
          - dumb-vga-dac
+          - lontium,lt8711uxd
          - parade,ps185hdm
```

Already has `Acked-by: Krzysztof Kozlowski`.

---
Generated by Claude Code Patch Reviewer

[PATCH 2/3] drm/bridge: simple: Add the Lontium LT8711UXD DP-to-HDMI bridge

[Dennis Gilmore]

The Lontium LT8711UXD is a high performance two lane Type-C/DP1.4 to
HDMI2.0 converter, designed to connect a USB Type-C source or a DP1.4
source to an HDMI2.0 sink. The device can be run uncontrolled or it can
be attached over I2C, this supports the uncontrolled mode.

Signed-off-by: Dennis Gilmore <dennis@ausil.us>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
---
 drivers/gpu/drm/bridge/simple-bridge.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/bridge/simple-bridge.c b/drivers/gpu/drm/bridge/simple-bridge.c
index 8aa31ca3c72d..42c1f3d5ba0c 100644
--- a/drivers/gpu/drm/bridge/simple-bridge.c
+++ b/drivers/gpu/drm/bridge/simple-bridge.c
@@ -270,6 +270,11 @@ static const struct of_device_id simple_bridge_match[] = {
 		.data = &(const struct simple_bridge_info) {
 			.connector_type = DRM_MODE_CONNECTOR_HDMIA,
 		},
+	}, {
+		.compatible = "lontium,lt8711uxd",
+		.data = &(const struct simple_bridge_info) {
+			.connector_type = DRM_MODE_CONNECTOR_HDMIA,
+		},
 	}, {
 		.compatible = "parade,ps185hdm",
 		.data = &(const struct simple_bridge_info) {
-- 
2.54.0

Claude review: drm/bridge: simple: Add the Lontium LT8711UXD DP-to-HDMI bridge

[Claude Code Review Bot]

Patch Review

**No issues.** The driver change adds the OF match table entry with `DRM_MODE_CONNECTOR_HDMIA`, placed in the correct alphabetical position between the existing `dumb-vga-dac` entry and `parade,ps185hdm`:

```c
+	}, {
+		.compatible = "lontium,lt8711uxd",
+		.data = &(const struct simple_bridge_info) {
+			.connector_type = DRM_MODE_CONNECTOR_HDMIA,
+		},
```

No `timings` struct is needed since the LT8711UXD is transparent in autonomous mode. Already has `Reviewed-by: Dmitry Baryshkov`.

---
Generated by Claude Code Patch Reviewer

[PATCH 3/3] arm64: dts: rockchip: orangepi-5-pro: Add LT8711UXD DP-to-HDMI bridge

[Dennis Gilmore]

Wire up the second HDMI port on the Orange Pi 5 Pro. It uses a Lontium
LT8711UXD high performance two lane Type-C/DP1.4 to HDMI2.0 converter,
designed to connect a USB Type-C source or a DP1.4 source to an HDMI2.0
sink. The bridge can be controlled via i2c or run as an autonomous device.

The Orange Pi 5 Pro has i2c wired up to i2c6, however there are 10k
resistors left off of R9 and R17 to enable MODE_SEL, and R27 for
I2C_ADDR resulting in MODE_SEL going to GND and the bridge let in
autonomous mode. As shipped I verified that the bridge does not show up
on the i2c bus.

Signed-off-by: Dennis Gilmore <dennis@ausil.us>
---
 .../dts/rockchip/rk3588s-orangepi-5-pro.dts   | 88 ++++++++++++++++++-
 1 file changed, 85 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/boot/dts/rockchip/rk3588s-orangepi-5-pro.dts b/arch/arm64/boot/dts/rockchip/rk3588s-orangepi-5-pro.dts
index 895d954a9f23..67363709c4ca 100644
--- a/arch/arm64/boot/dts/rockchip/rk3588s-orangepi-5-pro.dts
+++ b/arch/arm64/boot/dts/rockchip/rk3588s-orangepi-5-pro.dts
@@ -14,6 +14,44 @@ aliases {
 		mmc2 = &sdio;
 	};
 
+	hdmi1-con {
+		compatible = "hdmi-connector";
+		label = "HDMI1 OUT";
+		type = "a";
+
+		port {
+			hdmi1_con_in: endpoint {
+				remote-endpoint = <&lt8711uxd_out>;
+			};
+		};
+	};
+
+	hdmi-bridge {
+		compatible = "lontium,lt8711uxd";
+		vdd-supply = <&vcc3v3_dp>;
+
+		ports {
+			#address-cells = <1>;
+			#size-cells = <0>;
+
+			port@0 {
+				reg = <0>;
+
+				lt8711uxd_in: endpoint {
+					remote-endpoint = <&dp0_out_con>;
+				};
+			};
+
+			port@1 {
+				reg = <1>;
+
+				lt8711uxd_out: endpoint {
+					remote-endpoint = <&hdmi1_con_in>;
+				};
+			};
+		};
+	};
+
 	analog-sound {
 		compatible = "simple-audio-card";
 		pinctrl-names = "default";
@@ -72,6 +110,19 @@ fan: pwm-fan {
 		pwms = <&pwm2 0 20000000 0>;
 	};
 
+	vcc3v3_dp: regulator-vcc3v3-dp {
+		compatible = "regulator-fixed";
+		enable-active-high;
+		gpios = <&gpio3 RK_PC2 GPIO_ACTIVE_HIGH>;
+		pinctrl-names = "default";
+		pinctrl-0 = <&dp_bridge_en>;
+		regulator-max-microvolt = <3300000>;
+		regulator-min-microvolt = <3300000>;
+		regulator-name = "vcc3v3_dp";
+		regulator-always-on;
+		vin-supply = <&vcc_3v3_s3>;
+	};
+
 	vcc3v3_eth: regulator-vcc3v3-eth {
 		compatible = "regulator-fixed";
 		enable-active-high;
@@ -116,6 +167,24 @@ typea_con: usb-a-connector {
 	};
 };
 
+&dp0 {
+	pinctrl-names = "default";
+	pinctrl-0 = <&dp0m0_pins>;
+	status = "okay";
+};
+
+&dp0_in {
+	dp0_in_vp1: endpoint {
+		remote-endpoint = <&vp1_out_dp0>;
+	};
+};
+
+&dp0_out {
+	dp0_out_con: endpoint {
+		remote-endpoint = <&lt8711uxd_in>;
+	};
+};
+
 &i2c1 {
 	pinctrl-names = "default";
 	pinctrl-0 = <&i2c1m4_xfer>;
@@ -217,6 +286,12 @@ bt_wake_host_irq: bt-wake-host-irq {
 		};
 	};
 
+	dp {
+		dp_bridge_en: dp-bridge-en {
+			rockchip,pins = <3 RK_PC2 RK_FUNC_GPIO &pcfg_pull_down>;
+		};
+	};
+
 	ethernet {
 		ethernet_en: ethernet-en {
 			rockchip,pins = <3 RK_PB7 RK_FUNC_GPIO &pcfg_pull_down>;
@@ -350,9 +425,16 @@ &usb_host0_xhci {
 
 &usbdp_phy0 {
 	/*
-	 * The USB3 Type-A host connector is wired to PHY lanes 2/3. Lanes 0/1
-	 * are connected to the LT8711UXD DP-to-HDMI bridge on the board.
-	 * dp-lane-mux routes USB3 SuperSpeed to the correct lanes.
+	 * USBDP PHY0 is wired to a USB3 Type-A host connector via lanes 2/3.
+	 * Additionally lanes 0/1 and the aux channel are wired to the
+	 * Lontium LT8711UXD DP-to-HDMI bridge feeding the HDMI1 connector.
 	 */
 	rockchip,dp-lane-mux = <0 1>;
 };
+
+&vp1 {
+	vp1_out_dp0: endpoint@a {
+		reg = <ROCKCHIP_VOP2_EP_DP0>;
+		remote-endpoint = <&dp0_in_vp1>;
+	};
+};
-- 
2.54.0

Claude review: arm64: dts: rockchip: orangepi-5-pro: Add LT8711UXD DP-to-HDMI bridge

[Claude Code Review Bot]

Patch Review

This wires up the full display pipeline: VOP2 vp1 → dp0 → LT8711UXD bridge → HDMI1 connector. A few observations:

**1. `regulator-always-on` (minor/acceptable):**

```dts
+	vcc3v3_dp: regulator-vcc3v3-dp {
+		...
+		regulator-always-on;
+	};
```

The cover letter documents the HPD chicken-and-egg problem well: simple-bridge only calls `pre_enable` on modeset, but modeset won't start until HPD asserts, and HPD won't assert until the bridge is powered. Holding the supply on from boot is the standard workaround for autonomous bridges. Worth noting this means the enable GPIO stays asserted during suspend — on a desktop-class SBC this is unlikely to matter, but it's a trade-off to be aware of.

**2. Missing `status = "okay"` on `&usbdp_phy0` (probably fine):**

The `&usbdp_phy0` override only updates the comment and keeps the existing `rockchip,dp-lane-mux = <0 1>;`. The base DTS (from the earlier Orange Pi 5 Pro series) presumably already enables the PHY for the USB3 Type-A port. Just confirming that the prior series does set `status = "okay"` there — if it doesn't, DP won't work.

**3. VOP2/DP pipeline matches existing patterns:**

The `&vp1` endpoint and `&dp0_in`/`&dp0_out` wiring matches the established pattern from boards like indiedroid-nova and coolpi-4b:

```dts
+&vp1 {
+	vp1_out_dp0: endpoint@a {
+		reg = <ROCKCHIP_VOP2_EP_DP0>;
+		remote-endpoint = <&dp0_in_vp1>;
+	};
+};
```

This is correct — `ROCKCHIP_VOP2_EP_DP0` = 10 = 0xa, matching the `endpoint@a` unit address.

**4. Bridge node naming (nit):**

```dts
+	hdmi-bridge {
+		compatible = "lontium,lt8711uxd";
```

Some Rockchip DTS maintainers might prefer a more descriptive node name (e.g., `dp-to-hdmi-bridge`) but `hdmi-bridge` is fine and used by other boards.

**5. `dp-lane-mux = <0 1>` (correct):**

Using lanes 0/1 for DP and implicitly leaving lanes 2/3 for USB3 SuperSpeed matches the board's schematic description where the Type-A host connector uses the other pair. This is the same pattern as coolpi-4b.

**Overall for patch 3:** Looks correct and well-structured. No blocking issues.

---
Generated by Claude Code Patch Reviewer

Claude review: drm/bridge: Add Lontium LT8711UXD DP-to-HDMI transparent bridge

[Claude Code Review Bot]

Overall Series Review

Subject: drm/bridge: Add Lontium LT8711UXD DP-to-HDMI transparent bridge
Author: Dennis Gilmore <dennis@ausil.us>
Patches: 4
Reviewed: 2026-05-05T11:54:23.781624

---

This is a clean, well-structured 3-patch series adding support for the Lontium LT8711UXD DP-to-HDMI bridge in autonomous (strapping-resistor) mode to the simple-bridge framework, and wiring it up on the Orange Pi 5 Pro. The series is minimal and correctly follows existing patterns — the dt-binding and driver patches are essentially one-line additions to existing tables. Patch 1 has an Acked-by from the DT maintainer, and patch 2 has a Reviewed-by from Dmitry Baryshkov. The DTS patch (3/3) is the bulk of the work and follows established Rockchip DP bridge patterns (matches the coolpi-4b and indiedroid-nova wiring closely). The `regulator-always-on` workaround for the HPD/power deadlock is well-documented in the cover letter.

No blocking issues. A few minor observations below.

---
Generated by Claude Code Patch Reviewer