[经验]

芯灵思SinlinxA33开发板Linux中断编程4-最终代码(1)

王选

2019-2-13 16:09:15

12044

按键驱动代码：

#include
#include
#include
#include
#include
#include
#include
#include
#include
#define DEVICE_BUTTON "mybtn"
#define BTN_MAJOR 255
static char keybuf[] = {"0"};
static struct miscdevice misc = {
.minor = BTN_MAJOR,
.name = DEVICE_BUTTON,
};
irqreturn_t key_isr(int irq, void* dev)
{
int btn = 0;
//读取按键状态
btn= !gpio_get_value(GPIOL(14));
printk("key %srn", btn ? "down" : "up");
//把按键状态更新到对应的按缓冲中
keybuf = “0” + btn;
return IRQ_HANDLED;
}
static ssize_t btn_read (struct file *flp, char __user *buff, size_t count, loff_t * off)
{
int ret ;
if(!count) {
return 0;
}
ret = copy_to_user(buff, keybuf, count);
if(ret) {
printk("error:copy_to_userrn");
return -EFAULT;
}
return count;
}
static const struct file_operations dev_fops = {
.read = btn_read ,
.owner = THIS_MODULE,
};
static int __init btn_init(void)
{
int ret;
int irq;
int flags;
flags = IRQ_TYPE_EDGE_BOTH;
irq = gpio_to_irq( GPIOL(14) );
//发生中断号为irq的中断会执行key_isr函数。注册成功会在/proc/irq号/KEY文件夹出现或 cat /proc/interrupts, 记录了本中断发生的次数cat /proc/irq/442/spurious
ret = request_irq(irq,key_isr, flags, "KEY",NULL);
if(ret < 0)
{
irq = gpio_to_irq( GPIOL(14) );
disable_irq(irq);
free_irq(irq, NULL);
return ret;
}
ret = misc_register(&misc);
printk(KERN_EMERG " Device registered n ");
return ret;
}
static void __exit btn_exit(void)
{
int irq;
irq = gpio_to_irq( GPIOL(14) );
disable_irq(irq);
free_irq(irq, NULL);
misc_deregister(&misc);
printk(KERN_EMERG " Equipment logged out n");
}
module_init(btn_init);
module_exit(btn_exit);
MODULE_LICENSE("GPL");