BSP_调试经验

初始化spi屏幕

V3s

主线Linux5.14

st7789V 240*240

1.修改fbtft-core.c申请GPIO函数

//添加头文件
#include <linux/gpio.h>
#include <linux/of_gpio.h>
//.......
//找到fbtft_request_one_gpio()函数，替换
static int fbtft_request_one_gpio(struct fbtft_par *par,
                  const char *name, int index,
                  struct gpio_desc **gpiop)
{
    struct device *dev = par->info->device;
    struct device_node *node = dev->of_node;
    int gpio, flags, ret = 0;
    enum of_gpio_flags of_flags;

    if (of_find_property(node, name, NULL)) {
        gpio = of_get_named_gpio_flags(node, name, index, &of_flags);
        if (gpio == -ENOENT)
            return 0;
        if (gpio == -EPROBE_DEFER)
            return gpio;
        if (gpio < 0) {
            dev_err(dev,
                "failed to get '%s' from DT\n", name);
            return gpio;
        }
        flags = (of_flags & OF_GPIO_ACTIVE_LOW) ? GPIOF_OUT_INIT_LOW :
                            GPIOF_OUT_INIT_HIGH;
        ret = devm_gpio_request_one(dev, gpio, flags,
                        dev->driver->name);
        if (ret) {
            dev_err(dev,
                "gpio_request_one('%s'=%d) failed with %d\n",
                name, gpio, ret);
            return ret;
        }

        *gpiop = gpio_to_desc(gpio);
        fbtft_par_dbg(DEBUG_REQUEST_GPIOS, par, "%s: '%s' = GPIO%d\n",
                            __func__, name, gpio);
    }

    return ret;
}

2.修改RESET函数

static void fbtft_reset(struct fbtft_par *par)
{
    if (!par->gpio.reset)
        return;
    fbtft_par_dbg(DEBUG_RESET, par, "%s()\n", __func__);
    gpiod_set_value_cansleep(par->gpio.reset, 1);
    msleep(10);
    gpiod_set_value_cansleep(par->gpio.reset, 0);
    msleep(200);
    gpiod_set_value_cansleep(par->gpio.reset, 1);
    msleep(10);
}

3.修改st7789v初始化函数

static int init_display(struct fbtft_par *par)
{
    par->fbtftops.reset(par);
    mdelay(50);
    write_reg(par,0x36,0x00);
    write_reg(par,0x3A,0x05);
    write_reg(par,0xB2,0x0C,0x0C,0x00,0x33,0x33);
    write_reg(par,0xB7,0x35);
    write_reg(par,0xBB,0x19);
    write_reg(par,0xC0,0x2C);
    write_reg(par,0xC2,0x01);
    write_reg(par,0xC3,0x12);
    write_reg(par,0xC4,0x20);
    write_reg(par,0xC6,0x0F);
    write_reg(par,0xD0,0xA4,0xA1);
    write_reg(par,0xE0,0xD0,0x04,0x0D,0x11,0x13,0x2B,0x3F,0x54,0x4C,0x18,0x0D,0x0B,0x1F,0x23);
    write_reg(par,0xE1,0xD0,0x04,0x0C,0x11,0x13,0x2C,0x3F,0x44,0x51,0x2F,0x1F,0x1F,0x20,0x23);
    write_reg(par,0x21);
    write_reg(par,0x11);
    mdelay(50);
    write_reg(par,0x29);
    mdelay(200);
    return 0;
}

4.添加设备树

&spi0 {
    clock-frequency = <100000000>;
    pinctrl-0 = <&spi0_pins_a &spi0_pins_b>;
    status = "okay";

    st7789v@0 {
        status = "okay";
        compatible = "sitronix,st7789v";
        reg = <0>;
        spi-max-frequency = <32000000>;
        rotate = <90>;
        rgb;
        fps = <30>;
        buswidth = <8>;
        reset = <&pio PC 6 GPIO_ACTIVE_LOW>;
        dc = <&pio PC 5 GPIO_ACTIVE_LOW>;
        led = <&pio PD 18 GPIO_ACTIVE_HIGH>;
        debug = <1>;
    };
};

5.配置内核

Device Drivers  --->
     [*] Staging drivers  --->
         <*>   Support for small TFT LCD display modules  --->
              <*>   FB driver for the ST7789V LCD Controller

6.编译

make -j8

不出意外的话，会输出

[    1.041255] fbtft_of_value: width = 240
[    1.045110] fbtft_of_value: height = 240
[    1.049035] fbtft_of_value: buswidth = 8
[    1.053007] fbtft_of_value: debug = 0
[    1.056675] fbtft_of_value: rotate = 0
[    1.060425] fbtft_of_value: fps = 33
[    1.601827] graphics fb0: fb_st7789v frame buffer, 240x240, 112 KiB video memory, 4 KiB buffer memory, fps=33, spi0.0 at 96 MHz

7.测试

# cat /dev/urandom > /dev/fb0 //雪花屏

设置 TFT-LCD作为终端控制台

1.设置 uboot中的 bootargs

setenv bootargs 'console=tty0 ......'

saveenv

2.修改/etc/inittab文件

console::respawn:/sbin/qetty -L console 0 vt100
#添加下面一句
tty0::askfirst:-/bin/sh 

3.重启

reboot