DM6446之GPIO中断

 /* drivers/char/davinci_dm644x_button.c*/


 /*******************************************************************************
  * HEADER FILES
  */
 #include <linux/device.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/init.h>
 #include <linux/sched.h>
 #include <linux/kernel.h>
 #include <linux/fs.h>
 #include <linux/err.h>
 #include <linux/kdev_t.h>
 #include <linux/slab.h>
 #include <linux/mm.h>
 #include <linux/io.h>
 #include <linux/platform_device.h>
 #include <linux/types.h>
 #include <linux/cdev.h>
 #include <asm/arch/hardware.h>
 #include <asm/arch/clock.h>
 #include <asm/arch/psc.h>
 #include <linux/delay.h>
 #include <asm/arch/gpio.h>
 #include <asm/delay.h>
 #include <linux/errno.h>
 #include <asm/arch/gpio.h>
 #include <linux/interrupt.h>
 #include <linux/irq.h>                     //define for irq number
 #include <asm-arm/arch-davinci/irqs.h>
 #include <asm-arm/arch-davinci/clock.h>
 #include <asm/arch-davinci/gpio.h>
 //#include <linux/interrupt.h>
 #include <asm/uaccess.h>
 #include <asm/io.h>


 /*******************************************************************************
  * LOCAL DEFINES
  */
 #define DEVICE_NAME "buttontest"   /*定义设备驱动的名字，或设备节点名称*/
 #define BUTTON_MAJOR 200 /*使用 cat /proc/devices查看不要和存在的char节点重复*/


 /*my app gpio define*/
 #define DM644X_GPIO_BUTTON         3    /*GPIO3*/
 //#define DM644X_GPIO_INIT IRQ_GPIO3
 #define DM644X_GPIO_INIT 51

 /* 中断事件标志, 中断服务程序将它置1，buttons_read将它清0 */
 static int value=1;  //按键的电平值，按下为0


 /*******************************************************************************
  * FUNCTION DEFINITIONS
  */
 /***************************************************************************
  * Function             - gpio_demux_pins
  * Functionality        - interrupt register set
  * Input Params - None
  * Return Value - None
  * Note                 - None
  ****************************************************************************/
 void gpio_demux_pins(void)
 {
 /* PINMUX address in dm6446 */
 unsigned long pmux0;

 int addr = IO_ADDRESS(0x01c40000);
 pmux0 = inl(addr)&0xfd7fffff;
 outl(pmux0,addr);
 printk("The PINMUX0 value is %x\n!",inl(addr));

 /*ARM INTERRUPT CONTROLLER REGISTER*/

 int io_add = IO_ADDRESS(0x01c48000);

 int irq = inl(io_add + 0x0c)|0x00800000;
 outl(irq,io_add + 0x0c);
 printk("irq value is %x\n",inl(io_add + 0x0c));

 int eint = inl(io_add + 0x1c)|0x80000;
 outl(eint,io_add + 0x1c);
 printk("eint value is %x\n",inl(io_add + 0x1c));

 /* GPIO3 interrupt controller register*/
 int io_addr = IO_ADDRESS(0x01c67000);

 /*set GPIO3 interrupt enable*/
 int binen = inl(io_addr + 0x08)|0x01;
 outl(binen,io_addr+0x08);
 printk("binen value is %x\n",inl(io_addr + 0x08));

 /*set GPIO3 direction*/
 int dir = inl(addr + 0x10)|0x08;
 outl(dir,addr+0x10);
 printk("dir value is %x\n",inl(addr + 0x10));

 /*set GPIO3 raising disable*/
 int ris_clr = inl(io_addr + 0x28)|0x08;
 outl(ris_clr,io_addr+0x28);
 printk("ris_clr value is %x\n",inl(io_addr + 0x28));

 /*set GPIO3 raising set*/
 int ris = inl(io_addr + 0x24)|0x08;
 outl(ris,io_addr+0x24);
 printk("ris value is %x\n",inl(io_addr + 0x24));

 /*the GPIO3 status*/
 printk("insta value is %x\n",inl(io_addr + 0x34));
 }


 static irqreturn_t buttons_interrupt(int irq, void *dev_id,struct pt_regs *regs)
 {
     value = gpio_get_value(DM644X_GPIO_BUTTON);
 printk(KERN_INFO "key is pressed!\n");

 printk("test, value = %d\n", value);
     return IRQ_HANDLED;
 }
 static int buttons_read(struct file *filp, char __user *buff, size_t count, loff_t *offp)
 {
 value = gpio_get_value(DM644X_GPIO_BUTTON);
 printk("In kernel key_read()!\n");   //打印调试信息

        /* 将按键状态复制给用户 */

  copy_to_user(buff, (void *)&value, sizeof(value));
 // ev_press = 0;
        printk("this is at kernel, value = %d\n", value);
        return  0;
 }




 static int buttons_open(struct inode *inode, struct file *file)
 {

 int result;
     int value;

 gpio_direction_input(DM644X_GPIO_BUTTON);
     set_irq_type(DM644X_GPIO_INIT, IRQ_TYPE_EDGE_RISING);     //RISING   or  Edge Falling type
 disable_irq(DM644X_GPIO_INIT);
 enable_irq(DM644X_GPIO_INIT);
 result = request_irq(DM644X_GPIO_INIT,buttons_interrupt,IRQ_DISABLED,"buttontest","key");
     if (result < 0)
     {
         printk(KERN_INFO "Cannot initialize IRQ \n");
         return result;
     }
     printk(KERN_INFO "initialize IRQ successful, result = %d\n", result);
     value = gpio_get_value(DM644X_GPIO_BUTTON);
     disable_irq(DM644X_GPIO_INIT);
 enable_irq(DM644X_GPIO_INIT);
     printk(KERN_INFO "value = %d\n", value);
     return 0;
 }





 static int buttons_close(struct inode *inode,struct file *filp)
 {
     free_irq(DM644X_GPIO_INIT, "key");
 disable_irq(DM644X_GPIO_INIT);
 gpio_free(DM644X_GPIO_BUTTON);
     return 0;
 }


 /*定义驱动设备文件API，在linux系统当中，任何设备都可以当做文件的方式操作，这一点和单片机和MCU有很大差别*/


 static const struct file_operations davinci_dm644x_gpio_fileops = {
     .owner   = THIS_MODULE,
     .open    = buttons_open,
     .release = buttons_close,
     .read    = buttons_read,
        //.ioctl   = buttons_ioctl,
 };


 static int __init davinci_dm644x_button_open(void) /*内核初始化会调用该函数*/
 {
     int ret;
 int test;

 gpio_demux_pins();

 gpio_direction_input(DM644X_GPIO_BUTTON);

 if(gpio_is_valid(DM644X_GPIO_BUTTON) < 0)
 {
 printk("gpio is invalid\n");
 return -EINVAL;
 }
 printk("gpio is valid\n");
     test = gpio_request(DM644X_GPIO_BUTTON, "buttons_interrupt");
 if(test < 0 )
 {
 printk("failed to request gpio\n");
 return -EINVAL;
 }
 printk("request gpio ok!\n");

     ret = register_chrdev(BUTTON_MAJOR, DEVICE_NAME, &davinci_dm644x_gpio_fileops);
     if(ret < 0)
     {
         printk(KERN_INFO "dm644x_button register falid!\n");
         return ret;
     }
     printk(KERN_INFO "dm644x_button initialized\n");
     return ret;
 }

 static void __exit davinci_dm644x_button_exit(void)
 {
     unregister_chrdev(BUTTON_MAJOR, DEVICE_NAME);
 printk(KERN_INFO "dm644x_button:exit\n");
 }

 module_init(davinci_dm644x_button_open);
 module_exit(davinci_dm644x_button_exit);


 MODULE_AUTHOR("azhgul");
 MODULE_LICENSE("Dual BSD/GPL");

这里选用GPIO3作为中断源，包括设置相应中断控制寄存器，bank0中断使能， RISING     or    Edge Falling type，已经GPIO管脚复用等问题。

应用程序如下所示。

 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
 #include <sys/ioctl.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <sys/select.h>
 #include <sys/time.h>
 #include <errno.h> /

 int main(void)
 {
     int fd,key_value,ret;
     fd=open("/dev/key",0);
     if(fd<0){
         perror("open /dev/key error!\n");
         exit(1);
     }
     printf("open /dev/key sucessfully!\n");
     while(1){
         ret=read(fd,&key_value,sizeof(key_value));
         printf("In main(),key_value is '%d'\n\n",key_value);
     }
    close(fd);
     return 0;
 }