驱动开发7 基于GPIO子系统编写LED驱动，编写应用程序进行测试设置定时器，5秒钟打印一次hello world

驱动代码

#include <linux/init.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_gpio.h>
#include <linux/gpio.h>
#include <linux/timer.h>
#include <linux/of_irq.h>
#include <linux/interrupt.h>
/*myled{                           led1-gpio=<&gpioe 10 0>;led2-gpio=<&gpiof 10 0>;led3-gpio=<&gpioe 8 0>;};
*/
struct device_node *dnode; //设备树节点对象指针
struct gpio_desc *gpiono; //gpio描述信息属性名
struct gpio_desc *gpiono2;
struct gpio_desc *gpiono3;struct timer_list mytimer;
//定时器处理函数
void mytimer_function(struct timer_list *timer)
{//LED1状态取反printk("hello world\n");gpiod_set_value(gpiono,!gpiod_get_value(gpiono));gpiod_set_value(gpiono2,!gpiod_get_value(gpiono2));gpiod_set_value(gpiono3,!gpiod_get_value(gpiono3));//再次启动定时器mod_timer(timer, jiffies + 5 * HZ);
}
static int __init mycdev_init(void)
{//解析设备树节点信息dnode = of_find_node_by_path("/myled");if(dnode == NULL){printk("解析设备树节点失败\n");return -ENXIO;}//获取LED1 GPIO编号gpiono = gpiod_get_from_of_node(dnode,"led1-gpio",0,GPIOD_OUT_LOW,NULL);if(IS_ERR(gpiono)){printk("获取GPIO编号失败\n");return -PTR_ERR(gpiono);}//获取LED2 GPIO编号gpiono2 = gpiod_get_from_of_node(dnode,"led2-gpio",0,GPIOD_OUT_LOW,NULL);if(IS_ERR(gpiono2)){printk("获取GPIO编号失败\n");return -PTR_ERR(gpiono2);}//获取LED3 GPIO编号gpiono3 = gpiod_get_from_of_node(dnode,"led3-gpio",0,GPIOD_OUT_LOW,NULL);if(IS_ERR(gpiono3)){printk("获取GPIO编号失败\n");return -PTR_ERR(gpiono3);}//初始化定时器对象timer_setup(&mytimer,mytimer_function,0);mytimer.expires=jiffies+HZ; //定时1s//注册定时器add_timer(&mytimer);return 0;
}
static void __exit mycdev_exit(void)
{//注销定时器del_timer(&mytimer);//灯灭gpiod_set_value(gpiono,0);gpiod_set_value(gpiono2,0);gpiod_set_value(gpiono3,0);//释放GPIO编号gpiod_put(gpiono);gpiod_put(gpiono2);gpiod_put(gpiono3);
}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");

效果演示