DM355上按键程序
DM355上按键程序 收藏
利用中断捕捉按键信息，延时去抖后即可读出
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/delay.h>
#include <linux/cdev.h>
#include <linux/devfs_fs_kernel.h>
#include <linux/poll.h>
#include <asm/arch/gio.h>
#include <asm/irq.h>
#include <asm/arch/irqs.h>
#include <linux/interrupt.h>
#include <linux/timer.h>
#include <linux/param.h>
#include <asm/uaccess.h>
#include <asm/hardware.h>
#define DEVICE_NAME "buttons" /* 加载模式后，执行”cat /proc/devices”命令看到的设备名称 */
#define BUTTON_NR_DEVS 1
struct button_irq_desc {
int irq;
int pin;
int number;
char *name;
};
#define GPIO8 8
#define GPIO9 9
#define GPIO5 5
#define GPIO6 6
#define GPIO7 7
/* For registeration of charatcer device */
#define BUTTONS_STATUS_GET 1
static struct cdev c_dev;
/* device structure to make entry in device */
static dev_t dev;
static struct class_simple *af_class = NULL;
/* 用来指定按键所用的外部中断引脚及中断触发方式, 名字 */
static struct button_irq_desc button_irqs [] = {
{IRQ_DM355_GPIO8, GPIO8, 0, "KEY1"}, /* K1 */
{IRQ_DM355_GPIO9, GPIO9, 1, "KEY2"}, /* K2 */
{IRQ_DM355_GPIO5, GPIO5, 2, "KEY3"}, /* K3 */
{IRQ_DM355_GPIO6, GPIO6, 3, "KEY4"}, /* K4 */
{IRQ_DM355_GPIO7, GPIO7, 4, "KEY5"}, /* K5 */
};
/* 按键被按下的次数(准确地说，是发生中断的次数) */
static volatile int key_values [] = {0, 0, 0, 0, 0};
/* 等待队列:
* 当没有按键被按下时，如果有进程调用davinci_buttons_read函数，
* 它将休眠
*/
static DECLARE_WAIT_QUEUE_HEAD(button_waitq);
/* 中断事件标志, 中断服务程序将它置1，davinci_buttons_read将它清0 */
static volatile int ev_press = 0;
static struct timer_list button_timer;
/* 中断服务程序 void *dev_id响应管脚的button_irqs[i] 因为每个管脚的中断都注册了响应的button_irqs[i]
err = request_irq(button_irqs[i].irq, buttons_interrupt, NULL, button_irqs[i].name, (void *)&button_irqs[i]);*/
static irqreturn_t buttons_interrupt(int irq, void *dev_id,struct pt_regs *regs)
{
int i;
struct button_irq_desc *button_irqs = (struct button_irq_desc *)dev_id;
//屏蔽按键中断
button_timer.data=(unsigned long)button_irqs;
for (i = 0; i <sizeof(button_irqs)/sizeof(button_irqs[0]) ; i++) {
gpio_interrupt_disable(button_irqs[i].pin,TRIGGER_FALLING_EDGE );
}
button_timer.expires=jiffies+HZ/100;
add_timer(&button_timer);
return IRQ_RETVAL(IRQ_HANDLED);
}
static void button_timer_handler(unsigned long data)
{
int i;
int KeyStatus=0;
struct button_irq_desc *button_irqs = (struct button_irq_desc *)data;
KeyStatus=gpio_get_value(button_irqs->pin);
if(KeyStatus==0)
{
key_values[button_irqs->number] += 1;
printk("the button %d was push down\n",button_irqs->number);
ev_press = 1; /* 表示中断发生了 */
wake_up_interruptible(&button_waitq); /* 唤醒休眠的进程 */
}
//重新开启按键中断
for (i = 0; i <sizeof(button_irqs)/sizeof(button_irqs[0]) ; i++) {
gpio_interrupt_enable(button_irqs[i].pin,TRIGGER_FALLING_EDGE );
}
}
/* 应用程序对设备文件/dev/buttons执行open(...)时，
* 就会调用davinci_buttons_open函数
*/
static int davinci_buttons_open(struct inode *inode, struct file *file)
{
int i;
int err;
__REG(0x01c4000c)&=0xf1ffffff;
for (i = 0; i <sizeof(button_irqs)/sizeof(button_irqs[0]) ; i++) {//
/* Enable interrupt generation from GPIO Bank 0 (GPIO0-GPIO15) */
gpio_interrupt_bank_enable(button_irqs[i].pin);
/* Configure GPIO1 as an input */
gpio_set_direction(button_irqs[i].pin, GIO_DIR_INPUT);
/* Configure GPIO1 to generate an interrupt on falling edge only */
gpio_interrupt_enable(button_irqs[i].pin,TRIGGER_FALLING_EDGE );
gpio_interrupt_disable(button_irqs[i].pin, TRIGGER_RISING_EDGE);
// 注册中断处理函数
err = request_irq(button_irqs[i].irq, buttons_interrupt, NULL,
button_irqs[i].name, (void *)&button_irqs[i]);
if (err)
break;
}
if (err) {
// 释放已经注册的中断
i--;
for (; i >= 0; i--) {
disable_irq(button_irqs[i].irq);
free_irq(button_irqs[i].irq, (void *)&button_irqs[i]);
}
return -EBUSY;
}else
{
init_timer(&button_timer);
button_timer.function=button_timer_handler;
}
return 0;
}
/* 应用程序对设备文件/dev/buttons执行close(...)时，
* 就会调用davinci_buttons_close函数
*/
static int davinci_buttons_close(struct inode *inode, struct file *file)
{
int i;
for (i = 0; i <sizeof(button_irqs)/sizeof(button_irqs[0]); i++) {//
// 释放已经注册的中断
disable_irq(button_irqs[i].irq);
free_irq(button_irqs[i].irq, (void *)&button_irqs[i]);
}
return 0;
}
/* 应用程序对设备文件/dev/buttons执行read(...)时，
* 就会调用davinci_buttons_read函数
*/
static int davinci_buttons_read(struct file *filp, char __user *buff,
size_t count, loff_t *offp)
{
unsigned long err;
if (!ev_press) {
if (filp->f_flags & O_NONBLOCK)/*非阻塞模式 */
return -EAGAIN;
else/*阻塞模式 休眠等待中断到来*/
/* 如果ev_press等于0，休眠 */
wait_event_interruptible(button_waitq, ev_press);
}
/* 执行到这里时，ev_press等于1，将它清0 */
ev_press = 0;
/* 将按键状态复制给用户，并清0 */
err = copy_to_user(buff, (const void *)key_values, min(sizeof(key_values), count));
memset((void *)key_values, 0, sizeof(key_values));
return err ? -EFAULT : min(sizeof(key_values), count);
}
/**************************************************
* 当用户程序调用select函数时，本函数被调用
* 如果有按键数据，则select函数会立刻返回
* 如果没有按键数据，本函数使用poll_wait等待
**************************************************/
static unsigned int davinci_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;
}
/***************************************************
*
*BUTTONS_STATUS_GET 取得当前按键的状态
*
***************************************************/
static int davinci_buttons_ioctl(struct inode *inode, struct file *file,unsigned int cmd, void *arg)
{
int i=0;
switch(cmd)
{
case BUTTONS_STATUS_GET:
{
/* 将按键状态复制给用户，并清0 */
for(i=0;i<5;i++)
{
key_values[i]=gpio_get_value(button_irqs[i].pin);
}
copy_to_user((char __user *)arg, (const void *)key_values,sizeof(key_values));
memset((void *)key_values, 0, sizeof(key_values));
printk("the button status check\n");
break;
}
default:
break;
}
return 0;
}
/* 这个结构是字符设备驱动程序的核心
* 当应用程序操作设备文件时所调用的open、read、write等函数，
* 最终会调用这个结构中的对应函数
*/
static struct file_operations davinci_buttons_fops = {
.owner = THIS_MODULE, /* 这是一个宏，指向编译模块时自动创建的__this_module变量 */
.open = davinci_buttons_open,
.release = davinci_buttons_close,
.read = davinci_buttons_read,
.poll = davinci_buttons_poll,
.ioctl = davinci_buttons_ioctl,
};
/*
*
*/
static int __init davinci_buttons_init(void)
{
int err;
int result= 0;
/* 注册字符设备驱动程序
* 参数为主设备号、设备名字、file_operations结构；
* 这样，主设备号就和具体的file_operations结构联系起来了，
* 操作主设备为BUTTON_MAJOR的设备文件时，就会调用davinci_buttons_fops中的相关成员函数
* BUTTON_MAJOR可以设为0，表示由内核自动分配主设备号
*/
dev=MKDEV(79,0);
result = register_chrdev_region(dev,1,DEVICE_NAME);
if (result < 0) {
printk("Error : Could not register character device");
return -ENODEV;
}
/* Initialize character device */
cdev_init(&c_dev, &davinci_buttons_fops);
c_dev.owner = THIS_MODULE;
c_dev.ops = &davinci_buttons_fops;
err = cdev_add(&c_dev, dev, 1);
if (err) {
printk("Error : Error in Adding Davinci buttons");
unregister_chrdev_region(dev, BUTTON_NR_DEVS);
return -err;
}
af_class = class_simple_create(THIS_MODULE, DEVICE_NAME);
if (!af_class) {
printk("Error : Error in creating device class");
unregister_chrdev_region(dev, BUTTON_NR_DEVS);
class_simple_device_remove(dev);
class_simple_destroy(af_class);
cdev_del(&c_dev);
return -EIO;
}
result =devfs_mk_cdev(dev, S_IFCHR | S_IRUSR | S_IWUSR,DEVICE_NAME);
if (result < 0) {
printk("Error : Error in devfs_mk_cdev");
unregister_chrdev_region(dev, BUTTON_NR_DEVS);
class_simple_device_remove(dev);
class_simple_destroy(af_class);
cdev_del(&c_dev);
return result;
}
/* register simple device class */
class_simple_device_add(af_class, dev, NULL, DEVICE_NAME);
printk("Button register Successfully\n");
return 0;
}
/*
*
*/
static void __exit davinci_buttons_exit(void)
{
/* 卸载驱动程序 */
unregister_chrdev_region(dev, BUTTON_NR_DEVS);
/* remove simple class device */
class_simple_device_remove(dev);
devfs_remove(DEVICE_NAME);
/* destroy simple class */
class_simple_destroy(af_class);
cdev_del(&c_dev);
printk("Button register release\n");
}
/* 这两行指定驱动程序的初始化函数和卸载函数 */
module_init(davinci_buttons_init);
module_exit(davinci_buttons_exit);
/* 描述驱动程序的一些信息，不是必须的 */
MODULE_AUTHOR("jiaxinxu"); // 驱动程序的作者
MODULE_DESCRIPTION("JC_IR BUTTON Driver"); // 一些描述信息
MODULE_LICENSE("GPL"); // 遵循的协议
insmod驱动后
输入cat /dev/buttons 显示按键的输出