资料下载
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git clone https://e.coding.net/weidongshan/linux/doc_and_source_for_drivers.git
视频观看
编程_配置LCD控制器_基于IMX6ULL
参考资料,GIT仓库里:
- 芯片资料
IMX6ULL\开发板配套资料\datasheet\Core_board\CPU\IMX6ULLRM.pdf
《Chapter 34 Enhanced LCD Interface (eLCDIF)》
- IMX6ULL的LCD裸机程序
IMX6ULL\source\03_LCD\05_参考的裸机源码\03_font_test
- 内核自带的IMX6ULL LCD驱动程序
- 驱动源码:
Linux-4.9.88\drivers\video\fbdev\mxsfb.c
- 设备树:
arch/arm/boot/dts/imx6ull.dtsi
arch/arm/boot/dts/100ask_imx6ull-14x14.dts
- 本节视频编写好的代码
IMX6ULL\source\03_LCD\09_lcd_drv_lcdcontroller_config_use_devicetree
- 引脚配置工具/设备树生成工具
- 打开:http://download.100ask.net/
- 找到开发板:“100ASK_IMX6ULL_PRO开发板”
- 下载开发板配套资料
- 下载完后,工具在如下目录里:
1. 硬件相关的操作
LCD驱动程序的核心就是:
- 分配fb_info
- 设置fb_info
- 注册fb_info
- 硬件相关的设置
硬件相关的设置又可以分为3部分:
- 引脚设置
- 时钟设置
- LCD控制器设置
2. 在设备树里指定LCD参数
framebuffer-mylcd {
compatible = "100ask,lcd_drv";
pinctrl-names = "default";
pinctrl-0 = <&mylcd_pinctrl>;
backlight-gpios = <&gpio1 8 GPIO_ACTIVE_HIGH>;
clocks = <&clks IMX6UL_CLK_LCDIF_PIX>,
<&clks IMX6UL_CLK_LCDIF_APB>;
clock-names = "pix", "axi";
display = <&display0>;
display0: display {
bits-per-pixel = <24>;
bus-width = <24>;
display-timings {
native-mode = <&timing0>;
timing0: timing0_1024x768 {
clock-frequency = <50000000>;
hactive = <1024>;
vactive = <600>;
hfront-porch = <160>;
hback-porch = <140>;
hsync-len = <20>;
vback-porch = <20>;
vfront-porch = <12>;
vsync-len = <3>;
hsync-active = <0>;
vsync-active = <0>;
de-active = <1>;
pixelclk-active = <0>;
};
};
};
};
3. 编程
3.1 从设备树获得参数
时序参数、引脚极性等信息,都被保存在一个display_timing结构体里:
参考内核文件:
drivers\video\of_display_timing.c
drivers\video\fbdev\mxsfb.c
3.2 使用参数配置LCD控制器
标签:porch,开发板,LCD,Linux,active,IMX6ULL,display From: https://blog.51cto.com/weidongshan/6609554