myplatform.c
cpp
#include <linux/init.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/of_gpio.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/mod_devicetable.h>
#include <linux/cdev.h>
char number = 1;
struct gpio_desc *led1;
unsigned int irqno;
struct timer_list timer;
unsigned int major = 0;
unsigned int minor = 0;
char *devname = "myplatform";
struct cdev *cdev;
struct class *cls;
struct device *dev;
// 封装操作方法
int led_open(struct inode *inode, struct file *file)
{
return 0;
}
ssize_t led_read(struct file *file, char *ubuf, size_t size, loff_t *lof)
{
unsigned long res = copy_to_user(ubuf, &number, size < sizeof(number) ? size : sizeof(number));
return res;
}
int led_close(struct inode *inode, struct file *file)
{
return 0;
}
// 定义一个操作方法结构体对象并且初始化
struct file_operations fops = {
.open = led_open,
.read = led_read,
.release = led_close,
};
irqreturn_t key_handler(int irq, void *dev)
{
number = !number;
gpiod_set_value(led1, !gpiod_get_value(led1));
return IRQ_HANDLED;
}
int pdrv_probe(struct platform_device *pdev)
{
unsigned int dnub;
printk("%s%s%d\n", __FILE__, __func__, __LINE__);
cdev = cdev_alloc();
if (!cdev)
{
printk("字符设备驱动对象申请空间失败\n");
return -1;
}
printk("字符设备驱动对象申请空间成功\n");
cdev_init(cdev, &fops);
if (alloc_chrdev_region(&dnub, minor, 1, devname))
{
printk("动态申请设备号失败\n");
return -1;
}
printk("动态申请设备号成功\n");
major = MAJOR(dnub);
if (cdev_add(cdev, MKDEV(major, minor), 1))
{
printk("注册驱动失败\n");
return -1;
}
printk("注册驱动成功\n");
cls = class_create(THIS_MODULE, devname);
if (IS_ERR(cls))
{
printk("向上提交目录失败\n");
return -1;
}
printk("向上提交目录成功\n");
dev = device_create(cls, NULL, MKDEV(major, minor), NULL, devname);
if (IS_ERR(cls))
{
printk("向上提交设备节点信息失败\n");
return -1;
}
printk("向上提交设备节点信息成功\n");
led1 = gpiod_get_from_of_node(pdev->dev.of_node, "led1-gpio", 0, GPIOD_OUT_HIGH, NULL);
if (IS_ERR(led1))
{
printk("解析GPIO失败\n");
return -1;
}
printk("解析GPIO成功\n");
irqno = irq_of_parse_and_map(pdev->dev.of_node, 0);
if (!irqno)
{
printk("中断号解析失败\n");
return -1;
}
printk("中断号解析成功\n");
if (request_irq(irqno, key_handler, IRQF_TRIGGER_FALLING, "key", NULL))
{
printk("中断注册失败\n");
return -1;
}
printk("中断注册成功\n");
return 0;
};
int pdrv_remove(struct platform_device *pdev)
{
printk("%s%s%d\n", __FILE__, __func__, __LINE__);
gpiod_set_value(led1, 0);
gpiod_put(led1);
device_destroy(cls, MKDEV(major, minor));
class_destroy(cls);
cdev_del(cdev);
unregister_chrdev_region(MKDEV(major, minor), 1);
kfree(cdev);
free_irq(irqno, NULL);
return 0;
}
struct of_device_id oftable[] = {
{
.name = "myplatform",
//.compatible = "hqyj,myplatform",
},
{},
};
struct platform_driver pdrv = {
.probe = pdrv_probe,
.remove = pdrv_remove,
.driver = {
.name = "abcd",
.of_match_table = oftable,
},
};
module_platform_driver(pdrv);
MODULE_LICENSE("GPL");
test.c
cpp
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include "head.h"
int main()
{
int fd;
char number;
fd = open("/dev/myplatform", O_RDWR);
if (fd < 0)
{
printf("文件打开失败\n");
return -1;
}
read(fd,&number,sizeof(number));
printf("number=%d\n",number);
close(fd);
return 0;
}
设备树
结果