linux之按键中断

查看原理图确认引脚

可以看到按键有两个，分别对应GPIO5_1和GPIO4_14

配置pinctrl，配置成GPIO模式

1.使用官方工具，配置下引脚

2.将生成的代码复制到设备树里

创建设备节点

生成二进制设备树文件

在工具链表下使用

make dtbs

或者使用

./scripts/dtc/dtc -I dts -O dtb -o tmp.dtb arch/arm/boot/dts/xxx.dts
// 编译 dts 为 dtb

都可以生成二进制设备树文件

#include 

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#include 


struct gpio_key{
	int gpio;
	struct gpio_desc *gpiod;
	int flag;
	int irq;
} ;

static struct gpio_key *gpio_keys_100ask;

static irqreturn_t gpio_key_isr(int irq, void *dev_id)
{
	struct gpio_key *gpio_key = dev_id;
	int val;
	val = gpiod_get_value(gpio_key->gpiod);
	

	printk("key %d %d\n", gpio_key->gpio, val);
	
	return IRQ_HANDLED;
}

/* 1. 从platform_device获得GPIO
 * 2. gpio=>irq
 * 3. request_irq
 */
static int gpio_key_probe(struct platform_device *pdev)
{
	int err;
	struct device_node *node = pdev->dev.of_node;
	int count;
	int i;
	enum of_gpio_flags flag;
	unsigned flags = GPIOF_IN;
		
	printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);

	count = of_gpio_count(node);
	if (!count)
	{
		printk("%s %s line %d, there isn't any gpio available\n", __FILE__, __FUNCTION__, __LINE__);
		return -1;
	}

	gpio_keys_100ask = kzalloc(sizeof(struct gpio_key) * count, GFP_KERNEL);
	for (i = 0; i < count; i++)
	{
		gpio_keys_100ask[i].gpio = of_get_gpio_flags(node, i, &flag);
		if (gpio_keys_100ask[i].gpio < 0)
		{
			printk("%s %s line %d, of_get_gpio_flags fail\n", __FILE__, __FUNCTION__, __LINE__);
			return -1;
		}
		gpio_keys_100ask[i].gpiod = gpio_to_desc(gpio_keys_100ask[i].gpio);
		gpio_keys_100ask[i].flag = flag & OF_GPIO_ACTIVE_LOW;

		if (flag & OF_GPIO_ACTIVE_LOW)
			flags |= GPIOF_ACTIVE_LOW;

		err = devm_gpio_request_one(&pdev->dev, gpio_keys_100ask[i].gpio, flags, NULL);

		
		gpio_keys_100ask[i].irq  = gpio_to_irq(gpio_keys_100ask[i].gpio);
	}

	for (i = 0; i < count; i++)
	{
		err = request_irq(gpio_keys_100ask[i].irq, gpio_key_isr, IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING, "100ask_gpio_key", &gpio_keys_100ask[i]);
	}
        
    return 0;
    
}

static int gpio_key_remove(struct platform_device *pdev)
{
	//int err;
	struct device_node *node = pdev->dev.of_node;
	int count;
	int i;

	count = of_gpio_count(node);
	for (i = 0; i < count; i++)
	{
		free_irq(gpio_keys_100ask[i].irq, &gpio_keys_100ask[i]);
	}
	kfree(gpio_keys_100ask);
    return 0;
}


static const struct of_device_id ask100_keys[] = {
    { .compatible = "100ask,gpio_key" },
    { },
};

/* 1. 定义platform_driver */
static struct platform_driver gpio_keys_driver = {
    .probe      = gpio_key_probe,
    .remove     = gpio_key_remove,
    .driver     = {
        .name   = "100ask_gpio_key",
        .of_match_table = ask100_keys,
    },
};

/* 2. 在入口函数注册platform_driver */
static int __init gpio_key_init(void)
{
    int err;
    
	printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
	
    err = platform_driver_register(&gpio_keys_driver); 
	
	return err;
}

/* 3. 有入口函数就应该有出口函数：卸载驱动程序时，就会去调用这个出口函数
 *     卸载platform_driver
 */
static void __exit gpio_key_exit(void)
{
	printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);

    platform_driver_unregister(&gpio_keys_driver);
}


/* 7. 其他完善：提供设备信息，自动创建设备节点                                     */

module_init(gpio_key_init);
module_exit(gpio_key_exit);

MODULE_LICENSE("GPL");

板子上执行

将生成的设备树文件放到板子上，放到/boot目录里，然后重启以下

安装驱动程序

然后执行echo “7 4 1 7” > /proc/sys/kernel/printk可以将printk函数输出的信息输出到终端。

按下按键就可以看到打印结果。