最近一直在找带中断的led驱动程序先贴出来方便自己复习。
/*Tiny6410_buttons_xyl.c*/
/*引用的头文件*/
#include <linux/module.h>
/*模块有关的*/
#include <linux/kernel.h>
/*内核有关的*/
#include <linux/fs.h>
/*文件系统有关的*/
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/poll.h>
#include <linux/irq.h>
#include <asm/irq.h>
/*中断*/
#include <asm/io.h>
#include <linux/interrupt.h>
/*linux中断*/
#include <asm/uaccess.h>
#include <mach/hardware.h>
#include <linux/platform_device.h>
#include <linux/cdev.h>
#include <linux/miscdevice.h>
#include <mach/map.h>
#include <mach/regs-clock.h>
#include <mach/regs-gpio.h>
/*寄存器设置*/
#include <plat/gpio-cfg.h>
#include <mach/gpio-bank-n.h>
#include <mach/gpio-bank-l.h>
#define DEVICE_NAME "buttons"
/*设备名*/
/*定义按钮中断的描述结构体*/
struct button_irq_desc {
int irq;
/*中断号,中断号唯一表示一个中断*/
int number;
/*编号*/
char *name;
/*名称*/
};
/*指定8个按键的信息*/
static struct button_irq_desc button_irqs [] = {
{IRQ_EINT( 0), 0, "KEY0"},
{IRQ_EINT( 1), 1, "KEY1"},
{IRQ_EINT( 2), 2, "KEY2"},
{IRQ_EINT( 3), 3, "KEY3"},
{IRQ_EINT( 4), 4, "KEY4"},
{IRQ_EINT( 5), 5, "KEY5"},
{IRQ_EINT(19), 6, "KEY6"},
{IRQ_EINT(20), 7, "KEY7"},
};
static volatile char key_values [] = {'0', '0', '0', '0', '0', '0', '0', '0'};
/*key_values数组,这个数组是存放按键操作结果的
0表示无数据可读,1表示有数据可读*/
static DECLARE_WAIT_QUEUE_HEAD(button_waitq);
/*button_waitq是按键等待队列的名称*/
/*宏DECLARE_WAIT_QUEUE_HEAD( )*/
/*该宏是创建了一个等待队列*/
/*等待队列,是进程调度的一种重要方法*/
/*按键一按下,就会激活其等待队列里的进程,来做相应的处理*/
/*按键的等待队列,或者说中断所设置的等待队列,*/
/*是中断处理中非常重要的资源,它大大扩展了中断处理的能力*/
static volatile int ev_press = 0;
/*初始为0*/
static irqreturn_t buttons_interrupt(int irq, void *dev_id)
/*参数dev_id ---具体是哪一个按钮*/
{
struct button_irq_desc *button_irqs = (struct button_irq_desc *)dev_id;
int down;
int number;
unsigned tmp;
udelay(0);
number = button_irqs->number;
switch(number) {
case 0: case 1: case 2: case 3: case 4: case 5:
tmp = readl(S3C64XX_GPNDAT);
down = !(tmp & (1<<number));
break;
case 6: case 7:
tmp = readl(S3C64XX_GPLDAT);
down = !(tmp & (1 << (number + 5)));
break;
default:
down = 0;
}
if (down != (key_values[number] & 1)) {
key_values[number] = '0' + down;
ev_press = 1;
wake_up_interruptible(&button_waitq);
}
return IRQ_RETVAL(IRQ_HANDLED);
}
static int s3c64xx_buttons_open(struct inode *inode, struct file *file)
/*s3c64xx_buttons_open()函数申明*/
/*驱动函数open调用的具体函数*/
/*由open函数具体实现硬件的初始化工作*/
/*以及软件的初始化工作*/
/*为我们的键盘设备的运行创造好环境*/
{
int i;
int err = 0;
for (i = 0; i < sizeof(button_irqs)/sizeof(button_irqs[0]); i++) {
if (button_irqs[i].irq < 0) {
continue;
}
err = request_irq(button_irqs[i].irq, buttons_interrupt, IRQ_TYPE_EDGE_BOTH,
button_irqs[i].name, (void *)&button_irqs[i]);
if (err)
break;
}
if (err) {
i--;
for (; i >= 0; i--) {
if (button_irqs[i].irq < 0) {
continue;
}
disable_irq(button_irqs[i].irq);
free_irq(button_irqs[i].irq, (void *)&button_irqs[i]);
}
return -EBUSY;
}
ev_press = 1;
return 0;
}
/*mini2440_buttons_close()函数的申明*/
/*release调用的具体函数*/
/*设备软件环境的拆卸*/
/*具体就是中断的释放工作*/
/*因为中断资源,也是系统宝贵的资源,所以不用的时候,要释放*/
static int s3c64xx_buttons_close(struct inode *inode, struct file *file)
{
int i;
for (i = 0; i < sizeof(button_irqs)/sizeof(button_irqs[0]); i++) {
if (button_irqs[i].irq < 0) {
continue;
}
free_irq(button_irqs[i].irq, (void *)&button_irqs[i]);
}
return 0;
}
/*mini2440_buttons_read()函数的申明*/
/*read调用的具体函数*/
/*由它读取键盘输入的结果*/
/*实质上就是读取key_values数组的值*/
/*它完成了键盘作为输入设备的核心功能*/
/*数组是否可读,要根据标志位ev_press来判断*/
/*如果数组可读,则读取数据到用户buffer中*/
/*如果数组不可读,则进程进入等待队列,等待到数组可读为止*/
/*等待队列机制,是中断管理中常用到的机制*/
/*因为有些进程经常需要等待某一事件的发生*/
static int s3c64xx_buttons_read(struct file *filp, char __user *buff, size_t count, loff_t *offp)
/*注意__user,指的是用户空间*/
/*即要把键盘的输入结果读取到用户空间去*/
{
unsigned long err;
if (!ev_press) {
if (filp->f_flags & O_NONBLOCK)
return -EAGAIN;
else
wait_event_interruptible(button_waitq, ev_press);
}
ev_press = 0;
err = copy_to_user((void *)buff, (const void *)(&key_values), min(sizeof(key_values), count));
return err ? -EFAULT : min(sizeof(key_values), count);
}
/*mini2440_buttons_poll()函数的申明*/
/*poll调用的具体函数*/
/*poll实质上是select的调用函数*/
/*如果有按键数据,则select会立刻返回*/
/*如果没有按键数据,则等待*/
/*实质上这是键盘等待输入的机制*/
static unsigned int s3c64xx_buttons_poll( struct file *file, struct poll_table_struct *wait)
{
unsigned int mask = 0;
poll_wait(file, &button_waitq, wait);
if (ev_press)
mask |= POLLIN | POLLRDNORM;
return mask;
}
/*file_operations结构体*/
/*驱动函数的设置*/
/*分别将前面的驱动函数设置进来*/
static struct file_operations dev_fops = {
.owner = THIS_MODULE,
.open = s3c64xx_buttons_open,
.release = s3c64xx_buttons_close,
.read = s3c64xx_buttons_read,
.poll = s3c64xx_buttons_poll,
};
static struct miscdevice misc = {
.minor = MISC_DYNAMIC_MINOR,
.name = DEVICE_NAME,
.fops = &dev_fops,
};
static int __init dev_init(void)
{
int ret;
ret = misc_register(&misc);
printk (DEVICE_NAME"\tinitialized\n");
return ret;
}
static void __exit dev_exit(void)
{
misc_deregister(&misc);
}
module_init(dev_init);
module_exit(dev_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("FriendlyARM Inc.");