RK3576开发板GPIO驱动入门教程，基于触觉智能开发板教学

gpio0 = &gpio0;
gpio1 = &gpio1;
gpio2 = &gpio2;
gpio3 = &gpio3;
gpio4 = &gpio4;

// 定义 LED 设备节点
/ {
    leds: leds {
        status = "okay";
        compatible = "gpio-leds";
        pinctrl-names = "default";
        pinctrl-0 = <&leds_gpio>;
        work_led: work {
            gpios = <&gpio4 RK_PC7 GPIO_ACTIVE_HIGH>;
            linux,default-trigger = "heartbeat";
        };
        hub_rst {
            gpios = <&gpio4 RK_PD0 GPIO_ACTIVE_HIGH>;
            default-state="on";
        };
    };

    // USB 电源控制
    cgpio:cgpios{
        status = "okay";
        compatible = "cust,cgpio";

        usb_pwr {	//SD-card、USB-A、Wi-Fi
            gpios = <&gpio0 RK_PB6 GPIO_ACTIVE_HIGH>;
            init-status = <1>;
        };
    };
};

&pinctrl {
    // LED 引脚配置
    led_pins: led-pins {
        rockchip,pins =
            <0 RK_PB4 RK_FUNC_GPIO &pcfg_pull_none>;
    };

    // 按键引脚配置
    key_pins: key-pins {
        rockchip,pins =
            <0 RK_PA0 RK_FUNC_GPIO &pcfg_pull_up>;
    };
};

&pinctrl {
    /* LED 引脚 - 无上拉（输出模式不需要） */
    leds_gpio: leds-gpio {
        rockchip,pins =
            <4 RK_PC7 RK_FUNC_GPIO &pcfg_pull_none>,  /* work_led */
            <4 RK_PD0 RK_FUNC_GPIO &pcfg_pull_none>;  /* hub_rst */
    };

    /* USB 电源 - 无上拉 */
    usb_pwr: usb-pwr {
        rockchip,pins =
            <0 RK_PB6 RK_FUNC_GPIO &pcfg_pull_none>;
    };

    /* 耳机检测 - 上拉（按键检测） */
    hp_det: hp-det {
        rockchip,pins = 
            <3 RK_PB0 RK_FUNC_GPIO &pcfg_pull_up>;
    };

    /* WiFi 唤醒 - 下拉 */
    wifi_host_wake_irq: wifi-host-wake-irq {
        rockchip,pins = 
            <0 RK_PB0 RK_FUNC_GPIO &pcfg_pull_down>;
    };

    /* 按键输入 - 上拉 */
    adc_keys_pins: adc-keys-pins {
        rockchip,pins =
            <0 RK_PA0 RK_FUNC_GPIO &pcfg_pull_up>;
    };

    /* I2C 引脚 - 上拉（I2C 标准需要） */
    i2c2m0_xfer: i2c2m0-xfer {
        rockchip,pins =
            <1 RK_PB3 9 &pcfg_pull_up>,  /* i2c2_sda_m0 */
            <1 RK_PB4 9 &pcfg_pull_up>;   /* i2c2_scl_m0 */
    };
};

#include <linux/gpio.h>
#include <linux/of_gpio.h>
#include <linux/platform_device.h>
struct my_gpio_dev {
    int gpio_led;
    int gpio_key;
};
static int my_gpio_probe(struct platform_device *pdev)
{
    struct device_node *np = pdev->dev.of_node;
    struct my_gpio_dev *priv;
    int ret;

    priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
    if (!priv)
        return -ENOMEM;

    /* 从设备树获取 GPIO 描述符 */
    priv->gpio_led = of_get_named_gpio(np, "led-gpios", 0);
    if (!gpio_is_valid(priv->gpio_led)) {
        dev_err(&pdev->dev, "Failed to get LED GPIO\n");
        return priv->gpio_led;
    }

    /* 申请并配置 GPIO */
    ret = devm_gpio_request_one(&pdev->dev, priv->gpio_led,
                                   GPIOF_OUT_INIT_LOW, "led");
    if (ret) {
        dev_err(&pdev->dev, "Failed to request LED GPIO\n");
        return ret;
    }

    /* 设置 GPIO 输出高电平（点亮 LED） */
    gpio_set_value(priv->gpio_led, 1);

    /* 按键 GPIO 配置为输入 */
    priv->gpio_key = of_get_named_gpio(np, "key-gpios", 0);
    ret = devm_gpio_request_one(&pdev->dev, priv->gpio_key,
                                   GPIOF_IN, "key");
    if (ret)
        return ret;

    /* 读取 GPIO 输入值 */
    int val = gpio_get_value(priv->gpio_key);
    dev_info(&pdev->dev, "Key value: %d\n", val);

    return 0;
}
static const struct of_device_id my_gpio_of_match[] = {
    { .compatible = "mycompany,my-gpio-device", },
    { }
};
static struct platform_driver my_gpio_driver = {
    .probe = my_gpio_probe,
    .driver = {
        .name = "my-gpio",
        .of_match_table = my_gpio_of_match,
    },
};

static irqreturn_t gpio_irq_handler(int irq, void *dev_id)
{
    struct my_gpio_dev *priv = dev_id;

    /* 消抖处理 */
    priv->key_pressed = !priv->key_pressed;

    return IRQ_HANDLED;
}
static int setup_gpio_irq(struct platform_device *pdev, 
                          struct my_gpio_dev *priv)
{
    int irq, ret;

    /* 将 GPIO 转换为 IRQ */
    irq = gpio_to_irq(priv->gpio_key);
    if (irq < 0)
        return irq;

    /* 申请中断 */
    ret = devm_request_irq(&pdev->dev, irq, gpio_irq_handler,
                           IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
                           "gpio-key", priv);
    if (ret)
        dev_err(&pdev->dev, "Failed to request IRQ\n");

    return ret;
}

# 导出 GPIO（以 GPIO4_PA2 为例）
# 计算 GPIO 编号：4 * 32 + 1 * 8 + 2 = 138
echo 138 > /sys/class/gpio/export
# 设置方向为输出
echo out > /sys/class/gpio/gpio138/direction
# 设置输出高电平（点亮 LED）
echo 1 > /sys/class/gpio/gpio138/value
# 设置输出低电平（熄灭 LED）
echo 0 > /sys/class/gpio/gpio138/value
# 释放 GPIO
echo 138 > /sys/class/gpio/unexport

# 查看 GPIO 占用情况
cat /sys/kernel/debug/gpio
# 查看 pinmux 配置
cat /sys/kernel/debug/pinctrl/pinctrl-rockchip/pinmux-pins
# 查看 pin 状态
cat /sys/kernel/debug/pinctrl/pinctrl-rockchip/pin

# 查看中断统计
cat /proc/interrupts | grep gpio
# 使用 devmem 直接读取寄存器
devmem 0xFE740000  # GPIO0 基地址
# 使用 io 命令（如有）
io -r -4 0xFE740000