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
#include
#include
#include
/* copy_to_user,copy_from_user */ #include
#include
#include
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
#include
#include
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