Difference between revisions of "LCD"
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| − | ==S5P4418/ | + | [[LCD/zh|查看中文]] |
| − | === | + | ==S5P4418/S5P6818 1wire backlight adjustment== |
| − | + | ===LCD backlight adjustment==== | |
<syntaxhighlight lang="bash"> | <syntaxhighlight lang="bash"> | ||
| − | + | sudo sh -c "echo '10' >/dev/backlight-1wire" | |
</syntaxhighlight> | </syntaxhighlight> | ||
| − | + | value range：0~127 | |
| − | === | + | ===Turn off the LCD backlight=== |
| − | + | ||
<syntaxhighlight lang="bash"> | <syntaxhighlight lang="bash"> | ||
| − | + | sudo sh -c "echo '0' >/dev/backlight-1wire" | |
</syntaxhighlight> | </syntaxhighlight> | ||
| − | == | + | ==RK3399 platform: adjust the LCD backlight== |
| − | + | The backlight can be controlled manually through the node in this path: /sys/class/backlight/backlight | |
| − | == | + | ==S5P6818 platform: Add your own screen support== |
| − | ===4. | + | ===Kernel 4.4=== |
| − | + | ====Display driver==== | |
| − | + | It is recommended to debug uboot v2016.01, the relevant files are located in board/s5p6818/nanopi3/ , focusing on lcds.c<br/> | |
| + | Debugging the kernel 4.4 again, the driver is drivers/gpu/drm/panel/panel-friendlyelec.c | ||
| + | ====Touch Screen Driver==== | ||
| + | You may refre to HD900 touch screen driver:<br/> | ||
| + | drivers/input/touchscreen/friendlyelec/st1572.c<br/> | ||
| + | Or the following driver: | ||
| + | drivers/input/touchscreen/st1232.c<br/> | ||
| − | ===3. | + | ===Kernel 3.4=== |
| − | + | For Android, to add your own screen support, you need to modify u-boot-2014.07 and linux-3.4.y. you can download and compile these 2 parts according to the wiki.<br/> | |
<br/> | <br/> | ||
u-boot-2014.07<br/> | u-boot-2014.07<br/> | ||
Latest revision as of 10:40, 9 September 2021
Contents
1 S5P4418/S5P6818 1wire backlight adjustment
1.1 LCD backlight adjustment=
sudo sh -c "echo '10' >/dev/backlight-1wire"
value range：0~127
1.2 Turn off the LCD backlight
sudo sh -c "echo '0' >/dev/backlight-1wire"
2 RK3399 platform: adjust the LCD backlight
The backlight can be controlled manually through the node in this path: /sys/class/backlight/backlight
3 S5P6818 platform: Add your own screen support
3.1 Kernel 4.4
3.1.1 Display driver
It is recommended to debug uboot v2016.01, the relevant files are located in board/s5p6818/nanopi3/ , focusing on lcds.c
Debugging the kernel 4.4 again, the driver is drivers/gpu/drm/panel/panel-friendlyelec.c
3.1.2 Touch Screen Driver
You may refre to HD900 touch screen driver:
drivers/input/touchscreen/friendlyelec/st1572.c
Or the following driver:
drivers/input/touchscreen/st1232.c
3.2 Kernel 3.4
For Android, to add your own screen support, you need to modify u-boot-2014.07 and linux-3.4.y. you can download and compile these 2 parts according to the wiki.
u-boot-2014.07
board/s5p6818/nanopi3/lcds.c - 包含了我们所支持的屏的时序信息
board/s5p6818/nanopi3/onewire.c - 这是一线的实现，主要是用来识别屏
board/s5p6818/nanopi3/board.c - bd_lcd_init() 是屏的初始化处理
对于用户自己的屏，可以先修改 lcds.c ，增加自己的屏的参数，然后强制使用自己的参数
另外，部分屏因硬件特性的差异，初始化时需要配置不同的IO驱动能力，这需要根据自己实际的情况来测试，具体可查看命令类似 _gpio_init 的函数
如果用户的屏的LVDS 接口的，则nanopi2_lcd_config 中是通过 LCD_VESA
uboot中屏显示正常后，便可移植linux-3.4.y
linux-3.4.y
arch/arm/plat-s5p6818/nanopi3/lcds.c - 和 uboot中的类似，包含了屏的时序参数
可将uboot已调试好的参数增加到这里，这时候需要留意一下内核命令参数 lcd=XXX ，uboot会传递此参数给内核。
4 T4，M4安卓7修改屏幕方向的问题
第一步: 使用Type-C连接PC与板子，在PC上使用adb 拉取板子上的文件到PC上
adb pull /system/build.prop
第二步: 在PC上修改 build.prop
a) 修改 ro.sf.hwrotation=90
b) 增加 sys.hwc.device.primary=HDMI-A
第三步: 在PC上使用以下命令将修改过的 build.prop 推送到板子
adb root; adb remount; adb push build.prop /system/
第四步: 重启板子，可使用以下命令重启板子
adb reboot
5 T4 H702E LCD driver
drivers/gpu/drm/panel/panel-friendlyelec.c
drivers/gpu/drm/panel/panel-friendlyelec.h
And DTS file:
arch/arm64/boot/dts/rockchip/rk3399-nanopi4-common.dtsi
Related configuration:
panel: edp-panel {
compatible = "lcds", "simple-panel";
status = "okay";
backlight = <&pwm_bl>;
power-supply = <&vcc_lcd>;
prepare-delay-ms = <20>;
enable-delay-ms = <20>;
ports {
edp_panel: endpoint {
remote-endpoint = <&edp_out>;
};
};
};
6 HD702 touch screen driver
touch screen: gt9xx
linux 3.4: drivers/input/touchscreen/gt9xx.c
linux 4.4: drivers/input/touchscreen/friendlyelec/gt9xx.c
