手里有块4寸的MIPI屏幕TFT08006，下面要完成哪吒开发板支持这块屏幕。
驱动
首先是屏幕驱动，LCD的驱动路径：
uboot的LCD驱动路径：lichee/brandy-2.0/u-boot-2018/drivers/video/sunxi/disp2/disp/lcd/
内核的LCD驱动路径：lichee/linux-5.4/drivers/video/fbdev/sunxi/disp2/disp/lcd/
可以看到，SDK已经集成了tft08006的驱动源文件。
下面要做的是分别修改uboot和内核的配置，保证tft08006的驱动分别编译到了uboot和内核。
修改uboot配置
执行cboot快捷命令进入uboot根目录，执行make menuconfig
→ Device Drivers
→ Graphics support
→ LCD panels select
[*] LCD support TFT08006 panel
修改内核配置
执行croot快捷命令进入SDK根目录，执行make kernel_menuconfig
→ Device Drivers
→ Graphics support
→ Frame buffer Devices
→ Video support for sunxi
→ LCD panels select
[*] LCD support tft08006 panel
设备树
下面要根据哪吒开发板的硬件设计，来修改设备树文件。原理图如下：
uboot设备树文件在device/config/chips/d1-h/configs/nezha/uboot-board.dts
vim device/config/chips/d1-h/configs/nezha/uboot-board.dts
修改lcd0节点
&lcd0 {
base_config_start = <1>;
lcd_used = <1>;
lcd_driver_name = “tft08006”;
lcd_backlight = <500>;
lcd_if = <4>;
lcd_x = <480>;
lcd_y = <800>;
lcd_width = <52>;
lcd_height = <52>;
lcd_dclk_freq = <25>;
lcd_pwm_used = <1>;
lcd_pwm_ch = <9>;
lcd_pwm_freq = <50000>;
lcd_pwm_pol = <1>;
lcd_pwm_max_limit = <255>;
lcd_hbp = <10>;
lcd_ht = <515>;
lcd_hspw = <5>;
lcd_vbp = <20>;
lcd_vt = <830>;
lcd_vspw = <5>;
lcd_dsi_if = <0>;
lcd_dsi_lane = <2>;
lcd_dsi_format = <0>;
lcd_dsi_te = <0>;
lcd_dsi_eotp = <0>;
lcd_frm = <0>;
lcd_io_phase = <0x0000>;
lcd_hv_clk_phase = <0>;
lcd_hv_sync_polarity= <0>;
lcd_gamma_en= <0>;
lcd_bright_curve_en = <0>;
lcd_cmap_en= <0>;
lcdgamma4iep= <22>;
lcd_gpio_0= <&pio PH 0 1 0 3 1>;
pinctrl-0 = <&dsi4lane_pins_a>;
pinctrl-1= <&dsi4lane_pins_b>;
base_config_end = <1>;
};
依据硬件原理图，定义管脚
&pio{
dsi4lane_pins_a: dsi4lane@0 {
allwinner,pins = “PD1”, “PD2”, “PD3”, “PD4”, “PD5”, “PD6”, “PD7”,“PD9”, “PD10”, “PD11”;
allwinner,pname = “PD1”, “PD2”, “PD3”, “PD4”, “PD5”, “PD6”,“PD7”, “PD9”, “PD10”, “PD11”;
allwinner,function = “dsi”;
allwinner,muxsel = <5>;
allwinner,drive = <3>;
allwinner,pull = <0>;
};
dsi4lane_pins_b: dsi4lane@1 {
allwinner,pins = "PD1", "PD2", "PD3", "PD4", "PD5", "PD6", "PD7","PD9", "PD10", "PD11";
allwinner,pname = "PD1", "PD2", "PD3", "PD4", "PD5", "PD6","PD7", "PD9", "PD10", "DP11";
allwinner,function = "io_disabled";
allwinner,muxsel = <0xf>;
allwinner,drive = <1>;
allwinner,pull = <0>;
};
}
内核设备树文件在device/config/chips/d1-h/configs/nezha/linux-5.4/board.dts
vim device/config/chips/d1-h/configs/nezha/linux-5.4/board.dts
修改&lcd0节点
&lcd0 {
base_config_start = <1>;
lcd_used= <1>;
lcd_driver_name = “tft08006”;
lcd_backlight= <500>;
lcd_if= <4>;
lcd_x= <480>;
lcd_y= <800>;
lcd_width= <52>;
lcd_height= <52>;
lcd_dclk_freq= <25>;
lcd_pwm_used= <1>;
lcd_pwm_ch= <9>;
lcd_pwm_freq= <50000>;
lcd_pwm_pol= <1>;
lcd_pwm_max_limit = <255>;
lcd_hbp= <10>;
lcd_ht= <515>;
lcd_hspw= <5>;
lcd_vbp= <20>;
lcd_vt= <830>;
lcd_vspw= <5>;
lcd_dsi_if= <0>;
lcd_dsi_lane= <2>;
lcd_dsi_format = <0>;
lcd_dsi_te= <0>;
lcd_dsi_eotp= <0>;
lcd_frm= <0>;
lcd_io_phase= <0x0000>;
lcd_hv_clk_phase = <0>;
lcd_hv_sync_polarity= <0>;
lcd_gamma_en= <0>;
lcd_bright_curve_en = <0>;
lcd_cmap_en= <0>;
lcdgamma4iep= <22>;
lcd_gpio_0= <&pio PH 0 1 0 3 1>;
pinctrl-0= <&dsi4lane_pins_a>;
pinctrl-1= <&dsi4lane_pins_b>;
base_config_end = <1>;
};
依据硬件原理图，定义管脚
&pio {
dsi4lane_pins_a: dsi4lane@0 {
allwinner,pins = “PD1”, “PD2”, “PD3”, “PD4”, “PD5”, “PD6”, “PD7”,“PD9”, “PD10”, “PD11”;
allwinner,pname = “PD1”, “PD2”, “PD3”, “PD4”, “PD5”, “PD6”,“PD7”, “PD9”, “PD10”, “PD11”;
allwinner,function = “dsi”;
allwinner,muxsel = <5>;
allwinner,drive = <3>;
allwinner,pull = <0>;
};
dsi4lane_pins_b: dsi4lane@1 {
allwinner,pins = "PD1", "PD2", "PD3", "PD4", "PD5", "PD6", "PD7","PD9", "PD10", "PD11";
allwinner,pname = "PD1", "PD2", "PD3", "PD4", "PD5", "PD6","PD7", "PD9", "PD10", "DP11";
allwinner,function = "io_disabled";
allwinner,muxsel = <0xf>;
allwinner,drive = <1>;
allwinner,pull = <0>;
};
}
编译并打包成镜像
croot
make -j4
pack
烧录并测试
将新镜像烧录到开发板后，在串口终端中输入：
lv_example 0
启动示例