IoTGateway/BSP/Android/Gettingstarted/How to set LCD
1. ROM 3420 (Current default display is LVDS)
a. If wanting to set LCD as default display, you can modify the device/fsl/rom_3420_a1/BoardConfig.mk as follows.
BOARD_KERNEL_CMDLINE := console=ttymxc0,115200 init=/init <span style="color:#FF0000;">video=mxcfb0:dev=ldb,bpp=32</span> video=mxcfb1:off video=mxcfb2:off video=mxcfb3:off vmalloc=256M androidboot.console=ttymxc0 consoleblank=0 androidboot.hardware=freescale cma=384M
For ROM7421 (Current default display is LVDS), please refer to device/fsl/rom_7421_a1/BoardConfig.mk
b. If you want to change the panel for your product, please modify the LDB parameters in /kernel_imx/arch/arm/boot/dts/imx6qdl-advantech.dtsi
Pleae refer to the Device-Tree bindings for LVDS Display Bridge (ldb) as follows
LVDS Display Bridge
=======
The LVDS Display Bridge device tree node contains up to two lvds-channel
nodes describing each of the two LVDS encoder channels of the bridge.
Required properties:
- #address-cells : should be <1>
- #size-cells : should be <0>
- compatible : should be "fsl,imx53-ldb" or "fsl,imx6q-ldb".
Both LDB versions are similar, but i.MX6 has an additional
multiplexer in the front to select any of the four IPU display
interfaces as input for each LVDS channel.
- gpr : should be <&gpr> on i.MX53 and i.MX6q.
The phandle points to the iomuxc-gpr region containing the LVDS
control register.
- clocks, clock-names : phandles to the LDB divider and selector clocks and to
the display interface selector clocks, as described in
Documentation/devicetree/bindings/clock/clock-bindings.txt
The following clocks are expected on i.MX53:
"di0_pll" - LDB LVDS channel 0 mux
"di1_pll" - LDB LVDS channel 1 mux
"di0" - LDB LVDS channel 0 gate
"di1" - LDB LVDS channel 1 gate
"di0_sel" - IPU1 DI0 mux
"di1_sel" - IPU1 DI1 mux
On i.MX6q the following additional clocks are needed:
"di2_sel" - IPU2 DI0 mux
"di3_sel" - IPU2 DI1 mux
The needed clock numbers for each are documented in
Documentation/devicetree/bindings/clock/imx5-clock.txt, and in
Documentation/devicetree/bindings/clock/imx6q-clock.txt.
Optional properties:
- pinctrl-names : should be "default" on i.MX53, not used on i.MX6q
- pinctrl-0 : a phandle pointing to LVDS pin settings on i.MX53,
not used on i.MX6q
- fsl,dual-channel : boolean. if it exists, only LVDS channel 0 should
be configured - one input will be distributed on both outputs in dual
channel mode
LVDS Channel
==
Each LVDS Channel has to contain a display-timings node that describes the
video timings for the connected LVDS display. For detailed information, also
have a look at Documentation/devicetree/bindings/video/display-timing.txt.
Required properties:
- reg : should be <0> or <1>
- crtcs : a list of phandles with index pointing to the IPU display interfaces
that can be used as video source for this channel.
- fsl,data-mapping : should be "spwg" or "jeida"
This describes how the color bits are laid out in the
serialized LVDS signal.
- fsl,data-width : should be <18> or <24>
example:
gpr: iomuxc-gpr@53fa8000 {
/* ... */
};
ldb: ldb@53fa8008 {
#address-cells = <1>;
#size-cells = <0>;
compatible = "fsl,imx53-ldb";
gpr = <&gpr>;
clocks = <&clks 122>, <&clks 120>,
<&clks 115>, <&clks 116>,
<&clks 123>, <&clks 85>;
clock-names = "di0_pll", "di1_pll",
"di0_sel", "di1_sel",
"di0", "di1";
lvds-channel@0 {
reg = <0>;
crtcs = <&ipu 0>;
fsl,data-mapping = "spwg";
fsl,data-width = <24>;
display-timings {
/* ... */
};
};
lvds-channel@1 {
reg = <1>;
crtcs = <&ipu 1>;
fsl,data-mapping = "spwg";
fsl,data-width = <24>;
display-timings {
/* ... */
};
};
};