The Lontium LT8912 MIPI-to-HDMI bridge converts the {cpu-family} MIPI-DSI signal to one suitable for HDMI displays.
To use this bridge, set the S1.4 micro-switch to OFF
Kernel configuration
You can manage the LT8912 support through the following kernel configuration option:
-
Lontium LT8912 MIPI-DSI to LVDS and HDMI/MHL bridge (
CONFIG_DRM_LONTIUM_LT8912
)
This option is enabled as built-in on the default ConnectCore 8M Nano kernel configuration file.
Kernel driver
The driver for the LT8912 bridge is located at:
File | Description |
---|---|
LT8912 MIPI-to-HDMI bridge driver |
Device tree bindings and customization
The LT8912 bridge is documented at
Documentation/devicetree/bindings/display/bridge/lontium,lt8912.txt
.
The LT8912 bridge is defined in the ConnectCore 8M Nano Development Kit device tree file.
Definition of the LT8912
&i2c3 {
clock-frequency = <100000>;
pinctrl-names = "default", "gpio";
pinctrl-0 = <&pinctrl_i2c3>;
pinctrl-1 = <&pinctrl_i2c3_gpio>;
scl-gpios = <&gpio5 18 GPIO_ACTIVE_HIGH>;
sda-gpios = <&gpio5 19 GPIO_ACTIVE_HIGH>;
status = "okay";
...
lt_bridge: lt8912@48 {
compatible = "lontium,lt8912";
reg = <0x48>;
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_lt8912>;
digi,dsi-reset = <&gpio3 7 GPIO_ACTIVE_LOW>;
hpd-gpios = <&gpio3 9 GPIO_ACTIVE_HIGH>;
digi,dsi-lanes = <4>;
status = "okay";
port {
lt8912_1_in: endpoint {
/* add lanes */
remote-endpoint = <&mipi_dsi_hdmi_out>;
};
};
};
};
...
&mipi_dsi {
status = "okay";
port@1 {
mipi_dsi_hdmi_out: endpoint {
remote-endpoint = <<8912_1_in>;
};
};
...
};
IOMUX configuration
The following IOMUX entry configures the associated reset and hotplug-detection GPIO pins.
pinctrl_lt8912: lt8912grp {
fsl,pins = <
/* Reset */
MX8MN_IOMUXC_NAND_DATA01_GPIO3_IO7 0x19
/* Interrupt */
MX8MN_IOMUXC_NAND_DATA03_GPIO3_IO9 0x19
>;
};