中国教学网站,潍坊知名网站建设服务商,wordpress主题汉化版,2022百度收录越来越难了编写LED灯的驱动#xff0c;使用GPIO子系统#xff0c;里面添加按键的中断处理
1.应用程序发送指令控制LED亮灭
2.按键1 按下#xff0c;led1电位反转 按键2按下#xff0c;led2电位反转 按键3 按下#xff0c;led3电位反转
驱动程序
#include linux/init.h
#…编写LED灯的驱动使用GPIO子系统里面添加按键的中断处理
1.应用程序发送指令控制LED亮灭
2.按键1 按下led1电位反转 按键2按下led2电位反转 按键3 按下led3电位反转
驱动程序
#include linux/init.h
#include linux/module.h
#include linux/fs.h
#include linux/io.h
#include linux/device.h
#include linux/of_irq.h
#include linux/interrupt.h
#include linux/of_gpio.h//功能码
#define LED_ON _IO(l,1)
#define LED_OFF _IO(l,0)// 定义一个变量保存主设备号
unsigned int major;
char kbuf[128] {0};
unsigned int led1;
unsigned int led2;
unsigned int led3;struct class *cls;
struct device *dev;
struct device_node *devn;
unsigned int irqno1;
unsigned int irqno2;
unsigned int irqno3;// 中断处理函数
irqreturn_t myirq_handle1(int irq, void *dev)
{printk(key1 press\n);gpio_set_value(led1, !gpio_get_value(led1));return IRQ_HANDLED;
}
irqreturn_t myirq_handle2(int irq, void *dev)
{printk(key2 press\n);gpio_set_value(led2, !gpio_get_value(led2));return IRQ_HANDLED;
}
irqreturn_t myirq_handle3(int irq, void *dev)
{printk(key3 press\n);gpio_set_value(led3, !gpio_get_value(led3));return IRQ_HANDLED;
}int mycdev_open(struct inode *inode, struct file *file)
{int a inode-i_rdev;file-private_data (void *)MINOR(a);printk(%s:%s:%d\n, __FILE__, __func__, __LINE__);return 0;
}ssize_t mycdev_read(struct file *file, char *ubuf, size_t size, loff_t *loff)
{printk(%s:%s:%d\n, __FILE__, __func__, __LINE__);unsigned long ret;if (size sizeof(kbuf)){size sizeof(kbuf);}ret copy_to_user(ubuf, kbuf, size);if (ret){printk(copy_to_user failed\n);return ret;}return 0;
}ssize_t mycdev_write(struct file *file, const char *ubuf, size_t size, loff_t *loff)
{printk(%s:%s:%d\n, __FILE__, __func__, __LINE__);if (size sizeof(kbuf)){size sizeof(kbuf);}long ret;ret copy_from_user(kbuf, ubuf, size);if (ret){printk(copy_from_user failed\n);return -EIO;}return 0;
}int mycdev_close(struct inode *inode, struct file *file)
{printk(%s:%s:%d\n, __FILE__, __func__, __LINE__);return 0;
}long mycdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{unsigned int a (unsigned int)file-private_data;switch (a){case 0:switch (cmd){case LED_ON:gpio_set_value(led1, 1);break;case LED_OFF:gpio_set_value(led1, 0);break;}break;case 1:switch (cmd){case LED_ON:gpio_set_value(led2, 1);break;case LED_OFF:gpio_set_value(led2, 0);break;}break;case 2:switch (cmd){case LED_ON:gpio_set_value(led3, 1);break;case LED_OFF:gpio_set_value(led3, 0);break;}break;}return 0;
}
struct file_operations fops {.open mycdev_open,.read mycdev_read,.write mycdev_write,.release mycdev_close,.unlocked_ioctl mycdev_ioctl,
};
int irq_init(void)
{int ret;// 解析按键的设备树节点devn of_find_node_by_path(/myirq);if (NULL devn){printk(解析设备树节点失败\n);return -EFAULT;}printk(解析设备树节点成功\n);// 根据设备树节点解析出软中断号irqno1 irq_of_parse_and_map(devn, 0);if (!irqno1){printk(解析软中断号失败\n);return -ENXIO;}printk(解析软中断号成功 irqno1%d\n, irqno1);irqno2 irq_of_parse_and_map(devn, 1);if (!irqno2){printk(解析软中断号失败\n);return -ENXIO;}printk(解析软中断号成功 irqno2%d\n, irqno2);irqno3 irq_of_parse_and_map(devn, 2);if (!irqno3){printk(解析软中断号失败\n);return -ENXIO;}printk(解析软中断号成功 irqno3%d\n, irqno3);// 注册中断ret request_irq(irqno1, myirq_handle1, IRQF_TRIGGER_FALLING, key1, NULL);if (ret){printk(注册中断失败\n);return ret;}printk(注册中断成功\n);ret request_irq(irqno2, myirq_handle2, IRQF_TRIGGER_FALLING, key2, NULL);if (ret){printk(注册中断失败\n);return ret;}printk(注册中断成功\n);ret request_irq(irqno3, myirq_handle3, IRQF_TRIGGER_FALLING, key3, NULL);if (ret){printk(注册中断失败\n);return ret;}printk(注册中断成功\n);return 0;
}static int __init mycdev_init(void)
{int i, ret;irq_init();devn of_find_node_by_path(/leds);if (NULL devn){printk(解析设备树节点失败\n);return -EFAULT;}printk(解析设备树节点成功\n);// 根据解析到的设备树节点指针解析出LED的gpio编号led1 of_get_named_gpio(devn, led1-gpios, 0);if (led1 0){printk(解析led1编号失败\n);return led1;}printk(解析led1编号成功\n);// 申请led编号ret gpio_request(led1, NULL);if (ret){printk(申请led编号失败\n);return ret;}printk(申请led编号成功\n);led2 of_get_named_gpio(devn, led2-gpios, 0);if (led2 0){printk(解析led2编号失败\n);return led2;}printk(解析led1编号成功\n);// 申请led编号ret gpio_request(led2, NULL);if (ret){printk(申请led编号失败\n);return ret;}printk(申请led编号成功\n);led3 of_get_named_gpio(devn, led3-gpios, 0);if (led3 0){printk(解析led3编号失败\n);return led3;}printk(解析led3编号成功\n);// 申请led编号ret gpio_request(led3, NULL);if (ret){printk(申请led编号失败\n);return ret;}printk(申请led编号成功\n);// 注册字符设备驱动major register_chrdev(0, mychrdev, fops);if (major 0){printk(register error\n);return major;}printk(register success\n);cls class_create(THIS_MODULE, myled);if (IS_ERR(cls)){printk(向上提交目录失败\n);return -PTR_ERR(cls);}printk(向上提交目录信息成功]\n);for (i 0; i 3; i){dev device_create(cls, NULL, MKDEV(major, i), NULL, myled%d, i);if (IS_ERR(dev)){printk(向上提交结点设备信息失败\n);return -PTR_ERR(dev);}}printk(向上提交设备节点成功\n);return 0;
}static void __exit mycdev_exit(void)
{// 注销中断free_irq(irqno1, NULL);free_irq(irqno2, NULL);free_irq(irqno3, NULL);// 释放led编号gpio_put(led1);gpio_put(led2);gpio_put(led3);// 销毁节点信息int i;for (i 0; i 3; i){device_destroy(cls, MKDEV(major, i));}// 销毁目录信息class_destroy(cls);// 注销字符设备驱动unregister_chrdev(major, mycdev);
}module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE(GPL);
应用程序
#include stdio.h
#include unistd.h
#include sys/types.h
#include sys/stat.h
#include fcntl.h
#include stdlib.h
#include string.h
#include sys/ioctl.h
//功能码
#define LED_ON _IO(l,1)
#define LED_OFF _IO(l,0)int main(int argc, char const *argv[])
{int a, b, c;char buf[128] {0};printf(invoking open\n);int fd1 open(/dev/myled0, O_RDWR);if (fd1 0){printf(open file failed);exit(-1);}int fd2 open(/dev/myled1, O_RDWR);if (fd2 0){printf(open file failed);exit(-1);}int fd3 open(/dev/myled2, O_RDWR);if (fd3 0){printf(open file failed);exit(-1);}while (1){printf(请选择LED灯1LED12(LED2) 3(LED3));scanf(%d, b);printf(请输入控制指令0关灯 1开灯);scanf(%d, a);switch (b){case 1:switch (a){case 1:ioctl(fd1, LED_ON);break;case 0:ioctl(fd1, LED_OFF);break;}break;case 2:switch (a){case 1:ioctl(fd2, LED_ON);break;case 0:ioctl(fd2, LED_OFF);break;}break;case 3:switch (a){case 1:ioctl(fd3, LED_ON);break;case 0:ioctl(fd3, LED_OFF);break;}break;}}printf(invoking close\n);close(fd1);close(fd2);close(fd3);return 0;
}
