1.基于GPIO子系统编写LED驱动,编写应用程序进行测试
stm32mp157a-fsmp1a.dts
内核程序:ledk.c
#include <linux/init.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_gpio.h>
#include <linux/delay.h>
#include <linux/timer.h>
struct device_node *dnode1;
struct gpio_desc *gpiono1;
struct gpio_desc *gpiono2;
struct gpio_desc *gpiono3;
struct timer_list mytimer;
unsigned int *vir_rcc;
struct class *cls;
struct device *dev;
int major;
char kbuf[128] = {0};
//定义操作方法
int mycdev_open(struct inode *inode, struct file *file)
{
printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
return 0;
}
ssize_t mycdev_read(struct file *file, char *ubuf, size_t size, loff_t *lof)
{
printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
int ret1=copy_to_user(ubuf,kbuf,size);
if(ret1)
{
printk("copy_to_user filed\n");
return -EIO;
}
return 0;
}
ssize_t mycdev_write(struct file *file, const char *ubuf, size_t size, loff_t *lof)
{
printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
int ret=copy_from_user(kbuf,ubuf,size);
if(ret)
{
printk("copy_from_user filed\n");
return -EIO;
}
//设定该GPIO管脚的输出值
if(!strcmp(kbuf,"off"))
{
gpiod_set_value(gpiono1,0);
gpiod_set_value(gpiono2,0);
gpiod_set_value(gpiono3,0);
}
else if(!strcmp(kbuf,"on"))
{
gpiod_set_value(gpiono1,1);
gpiod_set_value(gpiono2,1);
gpiod_set_value(gpiono3,1);
}
return 0;
}
int mycdev_close(struct inode *inode, struct file *file)
{
printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
return 0;
}
//定义操作方法结构体变量并赋值
struct file_operations fops = {
.open = mycdev_open,
.read = mycdev_read,
.write = mycdev_write,
.release = mycdev_close,
};
static int __init mycdev_init(void)
{
// 字符设备驱动注册
major = register_chrdev(0, "mychrdev", &fops);
if (major < 0)
{
printk("字符设备驱动注册失败\n");
return major;
}
printk("字符设备驱动注册成功:major=%d\n", major);
// 向上提交目录
cls = class_create(THIS_MODULE, "mychrdev");
if (IS_ERR(cls))
{
printk("向上提交目录失败\n");
return -PTR_ERR(cls);
}
printk("向上提交目录成功\n");
// 向上提交设备节点信息
int i; // 向上提交三次设备节点信息
for (i = 0; i < 3; i++)
{
dev = device_create(cls, NULL, MKDEV(major, i), NULL, "myled%d", i);
if (IS_ERR(dev))
{
printk("向上提交设备节点失败\n");
return -PTR_ERR(dev);
}
}
printk("向上提交设备节点成功\n");
//解析设备树节点信息
dnode1 = of_find_node_by_path("/myled");
if(dnode1 == NULL)
{
printk("path_find failed \n");
return -ENXIO;
}
//根据GPIO相关节点得到GPIO编号
gpiono1 = gpiod_get_from_of_node(dnode1,"led1-gpio",0,GPIOD_OUT_LOW,NULL);
if(IS_ERR(gpiono1))
{
printk("申请gpiono1信息失败 \n");
}
printk("申请gpiono1信息成功 \n");
gpiono2 = gpiod_get_from_of_node(dnode1,"led2-gpio",0,GPIOD_OUT_LOW,NULL);
if(IS_ERR(gpiono2))
{
printk("申请gpiono2信息失败 \n");
}
printk("申请gpiono2信息成功 \n");
gpiono3 = gpiod_get_from_of_node(dnode1,"led3-gpio",0,GPIOD_OUT_LOW,NULL);
if(IS_ERR(gpiono3))
{
printk("申请gpiono3信息失败 \n");
}
printk("申请gpiono3信息成功 \n");
//GPIO的状态
return 0;
}
static void __exit mycdev_exit(void)
{
//设定该GPIO管脚的输出值
gpiod_set_value(gpiono1,0);
gpiod_set_value(gpiono2,0);
gpiod_set_value(gpiono3,0);
//释放GPIO编号
gpiod_put(gpiono1);
gpiod_put(gpiono2);
gpiod_put(gpiono3);
// 销毁设备节点信息
int i;
for (i = 0; i < 3; i++)
{
device_destroy(cls, MKDEV(major, i));
}
// 销毁目录
class_destroy(cls);
// 注销字符设备驱动
unregister_chrdev(major, "mychrdev");
}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");
应用程序:ledu.c
#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
int main(int argc,const char * argv[])
{
int a=0;
char buf[128] = "";
char buf1[128] = "";
int fd1=open("/dev/myled0",O_RDWR);
int fd2=open("/dev/myled1",O_RDWR);
int fd3=open("/dev/myled2",O_RDWR);
if(fd1<0)
{
printf("打开设备文件1失败\n");
exit(-1);
}
if(fd2<0)
{
printf("打开设备文件2失败\n");
exit(-1);
}
if(fd3<0)
{
printf("打开设备文件3失败\n");
exit(-1);
}
memset(buf,0,sizeof(buf));
while(1)
{
printf("请输入灯的控制(1开灯/0关灯) => ");
scanf("%d",&a);
write(fd1,buf,sizeof(buf));
write(fd2,buf,sizeof(buf));
write(fd3,buf,sizeof(buf));
if(a == 1)
{
strcpy(buf,"on");
write(fd1,buf,sizeof(buf));
write(fd2,buf,sizeof(buf));
write(fd3,buf,sizeof(buf));
}
else if(a == 0)
{
strcpy(buf,"off");
write(fd1,buf,sizeof(buf));
write(fd2,buf,sizeof(buf));
write(fd3,buf,sizeof(buf));
}
read(fd1,buf1,sizeof(buf));
printf("buf1:%s\n",buf1);
}
return 0;
}
2.设置定时器,5秒钟打印一次hello world
内核程序
#include <linux/init.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_gpio.h>
#include <linux/delay.h>
#include <linux/timer.h>
struct device_node *dnode1;
struct gpio_desc *gpiono1;
struct gpio_desc *gpiono2;
struct gpio_desc *gpiono3;
struct timer_list mytimer;
char kbuf[128] = {0};
void mytimer_funtion(struct timer_list *timer)
{
//PRINTK
printk("阿巴阿巴阿巴阿巴阿巴\n");
gpiod_set_value(gpiono1,!gpiod_get_value(gpiono1));
//启用定时器
mod_timer(timer,jiffies + msecs_to_jiffies(5000));
}
static int __init mycdev_init(void)
{
//解析设备树节点信息
dnode1 = of_find_node_by_path("/myled");
if(dnode1 == NULL)
{
printk("path_find failed \n");
return -ENXIO;
}
//根据GPIO相关节点得到GPIO编号
gpiono1 = gpiod_get_from_of_node(dnode1,"led1-gpio",0,GPIOD_OUT_LOW,NULL);
if(IS_ERR(gpiono1))
{
printk("申请gpiono1信息失败 \n");
}
gpiono2 = gpiod_get_from_of_node(dnode1,"led2-gpio",0,GPIOD_OUT_LOW,NULL);
if(IS_ERR(gpiono2))
{
printk("申请gpiono2信息失败 \n");
}
gpiono3 = gpiod_get_from_of_node(dnode1,"led3-gpio",0,GPIOD_OUT_LOW,NULL);
if(IS_ERR(gpiono3))
{
printk("申请gpiono3信息失败 \n");
}
//分配定时器对象(timer_list)
//初始化定时器(timer_setup)
timer_setup(&mytimer,mytimer_funtion,0);
mytimer.expires = jiffies+HZ;
//注册定时器并启用(add_timer)
add_timer(&mytimer);
//GPIO的状态
return 0;
}
static void __exit mycdev_exit(void)
{
//设定该GPIO管脚的输出值
gpiod_set_value(gpiono1,0);
gpiod_set_value(gpiono2,0);
gpiod_set_value(gpiono3,0);
//释放GPIO编号
gpiod_put(gpiono1);
gpiod_put(gpiono2);
gpiod_put(gpiono3);
//注销定时器(del_timer)
del_timer(&mytimer);
}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");