一.设定屏幕参数
1.更改设备树下的lcd节点参数
目录：arch/arm/boot/dts/imx6ull-14x14-nand-7-1024x600-c.dts
点击查看代码
&i2c2 {
goodix_ts@5d {
reg = <0x5d>;
};
};
&lcdif {
display0: display {
bits-per-pixel = <32>;//16
bus-width = <24>;
display-timings {
native-mode = <&timing0>;
timing0: timing0 {
clock-frequency = <35000000>;/*35000000*/
hactive = <720>;
vactive = <720>;
hfront-porch = <46>;
hback-porch = <44>;
hsync-len = <2>;
vback-porch = <16>;//min: 12 zsq_normal:16 18
vfront-porch = <50>;//zsq_normal: 50 16
vsync-len = <5>;//zsq_normal 5 2
hsync-active = <0>;
vsync-active = <0>;
de-active = <1>;
pixelclk-active = <1>;
};
};
};
};
2.在设备树下增加模拟spi的设备节点
目录：arch/arm/boot/dts/imx6ull-14x14-evk.dts
点击查看代码
gpiomnspis {
#address-cells = <1>;
#size-cells = <1>;
compatible = "atkalpha-gpiomnspis";
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_gpio_mnspis>;
cs-gpio = <&gpio1 20 GPIO_ACTIVE_LOW>; //uart2-tx
gpio-sck = <&gpio1 21 0>; //uart2-rx
gpio-mosi = <&gpio1 23 0>; //rts
status = "okay";
};
3.在屏幕驱动的probe函数下，对屏幕进行初始化
目录：/drivers/video/fbdev/mxsfb.c
3.1首先找到"mxsfb_probe"函数，做如下处理
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static int mxsfb_probe(struct platform_device *pdev)
{
const struct of_device_id *of_id =
of_match_device(mxsfb_dt_ids, &pdev->dev);
struct resource *res;
struct mxsfb_info *host;
struct fb_info *fb_info;
struct pinctrl *pinctrl;
int irq = platform_get_irq(pdev, 0);
int gpio, ret;
lcd_spiinit(); //add lcd_spiinit() by me
if (of_id)
pdev->id_entry = of_id->data;
gpio = of_get_named_gpio(pdev->dev.of_node, "enable-gpio", 0);
if (gpio == -EPROBE_DEFER)
return -EPROBE_DEFER;
...
}
3.2lcd初始化代码如下
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void lcd_spiinit(void)
{
gpio_lcd_spi.nd = of_find_node_by_path("/gpiomnspis");
gpio_lcd_spi.cs_gpio = of_get_named_gpio(gpio_lcd_spi.nd, "cs-gpio", 0);
gpio_lcd_spi.gpio_mosi = of_get_named_gpio(gpio_lcd_spi.nd, "gpio-mosi", 0);
gpio_lcd_spi.gpio_sck = of_get_named_gpio(gpio_lcd_spi.nd, "gpio-sck", 0);
gpio_direction_output(gpio_lcd_spi.cs_gpio, 1);
gpio_direction_output(gpio_lcd_spi.gpio_mosi, 1);
gpio_direction_output(gpio_lcd_spi.gpio_sck, 1);
Wrt_Reg_3052(0xFF,0x30);
Wrt_Reg_3052(0xFF,0x52);
Wrt_Reg_3052(0xFF,0x01);
Wrt_Reg_3052(0xE3,0x00);
Wrt_Reg_3052(0x0A,0x01);
Wrt_Reg_3052(0x23,0xA0);//A2
...
}
点击查看代码
struct gpio_lcd_spi_dev{
dev_t devids; /* 设备号 */
//struct cdev cdev; /* cdev */
struct class *class; /* 类 */
struct device *device; /* 设备 */
int major; /* 主设备号 */
int minor; /* 次设备号 */
struct device_node *nd; /* 设备节点 */
int cs_gpio; /* led 所使用的 GPIO 编号 */
int gpio_mosi;
int gpio_sck;
};
static struct gpio_lcd_spi_dev gpio_lcd_spi;
#define OLED_MOSI_SET() gpio_set_value(gpio_lcd_spi.gpio_mosi, 1);
#define OLED_MOSI_CLR() gpio_set_value(gpio_lcd_spi.gpio_mosi, 0);
#define OLED_CLK_SET() gpio_set_value(gpio_lcd_spi.gpio_sck, 1);
#define OLED_CLK_CLR() gpio_set_value(gpio_lcd_spi.gpio_sck, 0);
#define OLED_CS_Clr() gpio_set_value(gpio_lcd_spi.cs_gpio, 0);
#define OLED_CS_Set() gpio_set_value(gpio_lcd_spi.cs_gpio, 1);
static void SPI_WriteByte1(uint8_t Data)
{
unsigned char i=0;
for(i=8;i>0;i--)
{
OLED_CLK_CLR(); //将时钟拉低拉高
if(Data&0x80)
{
OLED_MOSI_SET(); //写数据1
}
else
{
OLED_MOSI_CLR(); //写数据0
}
OLED_CLK_SET(); //发送1bit数据
Data<<=1;
//usleep(1000);
//mdelay(1);
}
}
void Wrt_Reg_3052(uint8_t dat,uint8_t cmd)
{
OLED_CS_Clr();
OLED_CLK_CLR(); //将时钟拉低拉高
OLED_MOSI_CLR();
OLED_CLK_SET(); //发送1bit数据
SPI_WriteByte1(dat);
OLED_CLK_CLR(); //将时钟拉低拉高
OLED_MOSI_SET();
OLED_CLK_SET();
SPI_WriteByte1(cmd);
OLED_CS_Set();
}
void lcd_spiinit(void)
{
gpio_lcd_spi.nd = of_find_node_by_path("/gpiomnspis");