DM8168 GPIO驱动与测试程序

本次测试针对GPIO1进行，挑选了GP1[31]，引脚的复用默认的就是GPIO

还是老规矩，贴上driver.c，Makefile，test.c：

dm8168_gpio.c:

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/uaccess.h> /* copy_to_user,copy_from_user */
#include <linux/miscdevice.h>
#include <linux/device.h>
#include <asm/io.h>

static struct class  *gpio_class;

volatile unsigned long *DIR;
volatile unsigned long *DAT;

int gpio_open (struct inode *inode,struct file *filp)

{
*DIR = 0x0;  //output
return 0;
}

ssize_t gpio_read (struct file *filp, char __user *buf, size_t count,loff_t *f_pos)
{
return 0;
}

ssize_t gpio_write (struct file *filp, const char __user *buf, size_t count,loff_t *f_pos)
{
char val_buf[2];
int ret;
ret = copy_from_user(val_buf,buf,count);

switch(val_buf[0])
{
case 0x31 :
*DAT = 0xf0000000;  //gp1[31]
break;
case 0x30 :
*DAT = 0x0;         //gp1[31]
break;
default :
break;
}
return count;
}

struct file_operations gpio_fops =
{
.owner   = THIS_MODULE,
.open    = gpio_open,
.read    = gpio_read,
.write   = gpio_write,
} ;

int major;
int gpio_init (void)
{

major = register_chrdev(0,"DM8168_gpio",&gpio_fops);
gpio_class = class_create(THIS_MODULE, "DM8168_gpio");
device_create(gpio_class,NULL,MKDEV(major,0),NULL,"gpio");

DIR = (volatile unsigned long *)ioremap(0x4804C134,4);
DAT = (volatile unsigned long *)ioremap(0x4804C13C,4);

printk ("gpio is ready\n");
return 0;
}

void gpio_exit (void)
{
unregister_chrdev(major,"DM8168_gpio");
device_destroy(gpio_class,MKDEV(major,0));
class_destroy(gpio_class);

iounmap(DIR);
iounmap(DAT);

printk ("module exit\n");
return ;
}

MODULE_LICENSE("GPL");
module_init(gpio_init);
module_exit(gpio_exit);

Makefile:

obj-m:= dm8168_gpio.o

CROSSCOMPILE := /opt/codesourcery/arm-2009q1/bin/arm-none-linux-gnueabi-

CC  := $(CROSSCOMPILE)gcc

KDIR:=/home/***/ti-ezsdk_dm816x-evm_5_03_01_15/board-support/linux-2.6.37-psp04.00.01.13.patch2

PWD :=$(shell pwd)

default:
$(MAKE) -C $(KDIR) M=$(PWD) modules ARCH=arm CROSS_COMPILE=arm-none-linux-gnueabi-
clean:
rm -rf *.ko *.o .*cmd *.mod.c .tmp_versions

gpio_test:

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

int main(int argc, char *argv[])
{
int  fd;
int  val=0;

fd=open("/dev/gpio",O_RDWR);

if(fd<0)
{
printf("open device failed !\n");
exit(1);
}
else
{
printf("open success ! \n");
}

write(fd,argv[1],1);

close(fd);
return 0;
}

测试 ：

模块编译后加载：insmod dm8168_gpio.ko

交叉编译测试程序：arm-none-linux-gnueabi-gcc -o gpio_test gpio_test.c

运行：./gpio_test 1

GP1[31]为3.3V

运行：./gpio_test 0

GP1[31]为0V