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library:rk3568:lcddrv
Table of Contents
LCD @ Core-3568J
1. 硬件信息
1.1 LCD接口
模块参数
分辨率：128×160
驱动芯片：ST7735S
接口类型：SPI
背光电流：30mA
电压：3.3V
模块接口
| pin | Name | Feature |
|---|---|---|
| 1 | NC | |
| 2 | GND | |
| 3 | LED- | |
| 4 | LED+ | |
| 5 | GND | |
| 6 | /RESET | 复位，低有效 |
| 7 | A0 | 指令/数据， L：指令，H：数据 |
| 8 | SDA | |
| 9 | SCK | |
| 10 | VCC | 电源2.8~3.3v |
| 11 | IOVCC | IO电压2.8~3.3v |
| 12 | /CS | 片选，低有效 |
| 13 | GND | |
| 14 | NC |
1.2 控制接口
| No | 信号 | pin@Core-3568J | pin@rk3568 | GPIO |
|---|---|---|---|---|
| 1 | /RESET | 169 | GPIO0_A6 | |
| 2 | /CS | 185 | SPI0_CS0_M0 | GPIO0_C6 |
| 3 | SCK | 175 | SPI0_CLK_M0 | GPIO0_B5 |
| 4 | SDA | 159 | SPI0_MOSI_M0 | GPIO0_B6 |
| 5 | CD | 173 | GPIO0_C1 | |
| 6 | BL | 171 | GPIO0_C3 |
2. Linux驱动设计（A）
采用gpio-leds + spidev方式连接LCD模块，模块端口信号采用两种驱动：
- io: /Reset,BL,CD信号，使用gpio-leds驱动
- spi: /CS,SCK,SDA使用spidev驱动
2.1 控制IO
2.1.1 dts
lcd_reset: reset {
label = "lcd:reset";
linux,default-trigger = "none";
default-state = "on";
gpios = <&gpio0 RK_PA6 GPIO_ACTIVE_HIGH>;
};
lcd_backlight: backlight {
label = "lcd:backlight";
linux,default-trigger = "none";
default-state = "on";
gpios = <&gpio0 RK_PC3 GPIO_ACTIVE_HIGH>;
};
lcd_data: data {
label = "lcd:data";
linux,default-trigger = "none";
default-state = "on";
gpios = <&gpio0 RK_PC1 GPIO_ACTIVE_HIGH>;
};
添加以上3个pin的gpio-leds节点，驱动成功后的访问入口为：
/sys/class/leds/lcd:reset /sys/class/leds/lcd:backlight /sys/class/leds/lcd:data
可以用命令测试这几个pin的状态：
# backlight = 1 echo 1 > /sys/class/leds/lcd:backlight # backlight = 0 echo 1 > /sys/class/leds/lcd:backlight
2.2 spidev配置
修改DTS及添加驱动到内核
2.2.1 内核配置spidev
Device Drivers ‐‐‐>
[*] SPI support ‐‐‐>
<*> Rockchip SPI controller driver
[*] User mode SPI device driver support
2.2.2 dts配置
- rk3568-firefly-mplayer.dtsi
添加节点spi0
&spi0 {
status = "okay";
max-freq = <50000000>;
pinctrl-0 = <&spi0m0_cs0 &spi0m0_cs0 &spi0m0_pins>;
pinctrl-1 = <&spi0m0_cs0 &spi0m0_cs0 &spi0m0_pins_hs>;
spidev@0 {
compatible = "rockchip,spidev";
reg = <0>; // CS0
spi-max-frequency = <5000000>;
};
};
- pinctrl-0/1 重写覆盖了原定义，cs脚使用 spi0m0_cs1 代替 spi0m0_cs0
- 停用冲突的管脚: uart8,pwm7等
2.3 Demo script
library/rk3568/lcddrv.txt · Last modified: 2022/11/02 23:55 by lhaosen
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