DM8168 GPIO驱动与測试程序

全栈程序员-站长 • 2021年11月29日上午9:00 • 未分类 • 阅读 62

大家好，又见面了，我是全栈君，祝每个程序员都可以多学几门语言。

本次測试针对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;
}

測试：

模块编译后载入：insmod dm8168_gpio.ko

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

执行：./gpio_test 1

GP1[31]为3.3V

执行：./gpio_test 0

GP1[31]为0V

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