关于 exynos 4412 按键中断 异步通知

以下是驱动测试代码：

//内核的驱动代码

#include <linux/init.h>

#include <linux/module.h> //for module_init moudule_exit

#include <linux/fs.h> //for MKDEV register_chrdev_region

#include <linux/cdev.h> //字符设备头文件

#include <linux/device.h>

#include <asm/io.h> //for ioremap

#include <linux/platform_device.h> //for 平台设备

#include <linux/of.h>

#include <linux/signal.h>

#include <linux/interrupt.h>

#define LED_MA 500 //主设备号(那一类设备)

//某些主设备号已经静态地分配给了大部分公用设备。见Documentation/devices.txt 。 这里我们常使用250

#define LED_MI 2 //次设备号(这类设备当中的具体哪个设备)

//目标:把字符设备改造为平台设备

//1. 把硬件信息，分离出去，放到设备树

//#define LED3CON 0X11000C20

//#define LED3DAT 0x11000c24

struct resource *led_res_con;

struct resource *led_res_dat;

struct resource *key1_res; //devices source pointer

struct fasync_struct *async_queue; /* 异步结构体指针，用于读 */

struct cdev led; //定义一个字符设备

#define LED_MAGIC 'L' //幻数，类似加密，避免误操作

#define LED_ON _IOW(LED_MAGIC, 1, int)

#define LED_OFF _IOW(LED_MAGIC,2,int)

unsigned int *led3_con;

unsigned int *led3_dat;

int led_open (struct inode *inode, struct file *file)

{

led3_con = ioremap((phys_addr_t)led_res_con,1); //把硬件的物理地址转换为内核的虚拟地址

if(led3_con == NULL){

printk("led3_con ioremap fail\n");

return -1;

}

led3_dat = ioremap((phys_addr_t)led_res_dat,1);

if(led3_dat == NULL){

printk("led3_dat ioremap fail\n");

return -1;

}

writel((readl(led3_con) & (~0xf)) | 1,led3_con);//led3 and key2 had use same register;

writel(1,led3_dat);

printk("led_open ok\n");

return 0;

}

int led_release(struct inode *inode, struct file *file)

{

free_irq(key1_res->start, NULL);

printk("remove OK\n");

printk("led_release ok\n");

return 0;

}

//实现自定义的个性化操作

long led_ioctl(struct file *file, unsigned int cmd, unsigned long args)

{

switch(cmd) //解析ioctl 命令

{

case LED_ON: //点亮灯

printk("led on cmd=%d\n",cmd);

writel(1,led3_dat);

break;

case LED_OFF: //灭灯

printk("led off cmd=%d\n",cmd);

writel(0,led3_dat);

break;

default:

printk("ioctl cmd no found\n");

break;

}

printk("led_ioctl end\n");

return 0;

}

irqreturn_t key_interrupt(int irqno, void *devid)

{

kill_fasync(&async_queue, SIGIO, POLL_IN); //发送SIGIO 异步通知信号

printk("irqno = %d\n", irqno);

return IRQ_HANDLED;

}

int key_fasync (int fd,struct file *filp,int mode)

{

return fasync_helper(fd,filp,mode,&async_queue);//处理标志的变更

}

//3.实现设备的文件操作

struct file_operations fops={ //设备的文件操作

.owner = THIS_MODULE,

.open = led_open,

.release = led_release,

.unlocked_ioctl = led_ioctl,

.fasync = key_fasync,

};

int led_init(struct platform_device *pdev) //把找到的平台设备的信息传进来

{

int ret;

dev_t dev_id= MKDEV(LED_MA, LED_MI); //把主次设备号合并生成设备ID

//1.注册设备号

ret =register_chrdev_region(dev_id,1,"test_led");

if(ret<0){

printk("regiser led fail\n ");

return -1;

}

//2.初始化字符设备

cdev_init(&led,&fops); //字符设备初始化

ret =cdev_add(&led,dev_id,1); //添加字符设备到系统中

if(ret<0){

printk("cdev add led fail\n ");

return -1;

}

led_res_con = pdev->resource[0].start;

led_res_dat = pdev->resource[1].start;

printk("led init go 1\n");

/*****************************************************/

key1_res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);

if (key1_res == NULL) {

printk("No resource !\n");

return -ENODEV;

}

ret = request_irq(key1_res->start, //硬件中断号 对应exynos4412-test4412.dts中test4412-key interrupts = <1 2>中的1

key_interrupt, //中断处理函数

key1_res->flags, //中断标志 IRQF_DISABLED 在表示中断处理时屏蔽掉其它所有中断

"key2", //中断名称 在cat /proc/interrupts 克看到

NULL);

if (ret < 0) {

printk("failed request irq: irqno = irq_res->start");

return ret;

}

printk("key irq init ok\n");

/*********************************************************/

return 0; //返回值为零表示运行成功 ，负值表示失败

}

void led_exit(void)

{

dev_t dev_id= MKDEV(LED_MA, LED_MI);

cdev_del(&led); //删除设备

unregister_chrdev_region(dev_id, 1); //取消注册

printk("led exit go\n");

}

//2.把内核模块的入口，改为platform_driver的入口

//module_init(led_init);

//module_exit(led_exit);

static const struct of_device_id machled[] = {

{ .compatible = "test,led3"}, //必须和设备树里的设备名字一样

{},

};

MODULE_DEVICE_TABLE(of, machled);

struct platform_driver led_platform_driver = {

.driver = {

.name = "test_led",

.owner = THIS_MODULE,

.of_match_table = of_match_ptr(machled),

},

.probe = led_init,

.remove = led_exit,

};

module_platform_driver(led_platform_driver); //声明led_platform_driver为平台设备驱动的加载入口

MODULE_LICENSE("Dual BSD/GPL");

接下来是测试代码：

#include <stdio.h>
#include <fcntl.h>

#include <unistd.h>

#include <stdlib.h>

#include <sys/ioctl.h>

#include <signal.h>

#include <sys/types.h>

#include <sys/stat.h>

#define LED_MAGIC 'L'

//#define LED_ON 1

//#define LED_OFF 2

#define LED_ON _IOW(LED_MAGIC, 1, int)

#define LED_OFF _IOW(LED_MAGIC,2,int)

int flag = 0;

void input_handler (int signum)

{

printf("receive a signal from globalfifo, signalnum : %d\n",signum);

flag = 1;

}

int main(int argc, char **argv)

{

int fd = open("/dev/led", O_RDWR);

if (fd < 0) {

printf("open /dev/led fail\n");

return -1;

}

int oflags;

signal(SIGIO, input_handler); //让input_handler()处理SIGIO信号

fcntl(fd, F_SETOWN, getpid()); //设置设备文件的所有者为本进程

oflags = fcntl(fd, F_GETFL); // 会调用 驱动中的 .fasync

fcntl(fd, F_SETFL, oflags | FASYNC); //FASYNC 设置支持异步通知模式

while(1)

{

sleep(100);

if (flag)

{

ioctl(fd, LED_OFF); //ioctl 实现设备的个性化操作（可自定义命令）

printf("LED_OFF\n"); //注意要加\n 否则打印信息可能没有

flag = 0;

}

}

}

最后测试下来还是有一些小问题，后续再看；