Hi Expert,
Customer know currently Ti will not put much effort to implement this u-boot feature.
Customer would like to know if they plan to do it by theirself, how can they do it?
Following is the steps I did, if anything is incorrect I would like Ti Expert can give me suggestions or direct me.
- Modify the device tree (DTS) of u-boot
- Add EPWM node and LCD backlight controls
/{
…
…
// lcd backlight pwm , ehpwm1
lcd_bl: backlight {
compatible = "pwm-backlight";
pwms = <&epwm1 0 50000 0>;
brightness-levels = <255 250 240 230 220 210 220 190 180 170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 6>;
default-brightness-level = <14>;
};
…
};
&main_pmx0 {
…
…
//Add folowing pinmux setting to declare the PIN "(B18) EHRPWM1_A or ECAP1_IN_APWM_OUT" is used for LCD Backlight PWM output.
main_lcd_dim_pin_default: lcd-dim-pins-default{
pinctrl-single,pins = <
AM62X_IOPAD(0x19C, PIN_OUTPUT, 6) /* (B18) EHRPWM1_A or ECAP1_IN_APWM_OUT */ /* LCD Panel PWM Dimming Control for Backlight*/
>;
};
}；
&epwm1 {
status = "okay";
pinctrl-names = "default";
pinctrl-0 = <&main_lcd_dim_pin_default>;
};
- Add Panel node for DPI Panel Device
/{
…
…
panel_lcd: panel_lcd{
bootph-pre-ram;
compatible = "simple-panel";
//compatible = "jspf,ph800480";
status= "okay";
backlight = <&lcd_bl>;
width-mm = <217>;
height-mm = <136>;
data-mapping = "vesa-24";
panel-timings {
bootph-pre-ram;
clock-frequency = <150274>;
hactive = <800>;
vactive = <480>;
hback-porch = <32>;
hfront-porch = <52>;
vback-porch = <24>;
vfront-porch = <8>;
hsync-len = <24>;
vsync-len = <3>;
de-active = <1>;
};
port {
lcd_in0: endpoint {
remote-endpoint = <&dpi1_out>;
};
};
};
};
- Add DSS and make it associate with DPI panel
&dss_ports {
#address-cells = <1>;
#size-cells = <0>;
/* VP1: DPI Output */
port@1 {
reg = <1>;
dpi1_out: endpoint {
remote-endpoint = <&lcd_in0>;
};
};
};
- Add simple panel support and related modules in menuconfig of u-boot
CONFIG_VIDEO_LOGO=y
CONFIG_BACKLIGHT=y
CONFIG_VIDEO_BPP8=y
CONFIG_VIDEO_BPP16=y
CONFIG_VIDEO_BPP32=y
CONFIG_VIDEO_ANSI=y
CONFIG_PANEL=y
CONFIG_SIMPLE_PANEL=y
It looks I missed some steps, the DPI panel cannot work, is there anything I can check to identify problems?
Thanks
Daniel
