TQ2440開發板 Linux第一個驅動--點燈

ID:72519 · 發表于 2015-1-20 02:33

我用的是TQ2440開發板,這個程序是參考韋東山的.

4盞LED燈

以下是驅動程序

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <asm/uaccess.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <asm/arch/regs-gpio.h>
#include <asm/hardware.h>
static struct class *firstdrv_class;
static struct class_device *firstdrv_class_dev;
volatile unsigned long *gpbcon = NULL;
volatile unsigned long *gpbdat = NULL;
static int first_drv_open(struct inode *inode, struct file *file)
{
//printk("first_drv_open\n");
/* 配置gpb5,6,7,8為輸出 */
*gpbcon &= ~((0x3<<(5*2)) | (0x3<<(6*2)) | (0x3<<(7*2)) | (0x3<<(8*2)));
*gpbcon |= ((0x1<<(5*2)) |(0x1<<(6*2)) | (0x1<<(7*2)) | (0x1<<(8*2)));
return 0;
}
static ssize_t first_drv_write(struct file *file, const char __user *buf, size_t count, loff_t * ppos)
{
int val;
//printk("first_drv_write\n");
copy_from_user(&val, buf, count); // copy_to_user();
if (val == 1)
{
// 點燈
*gpbdat &= ~((1<<5) | (1<<6) | (1<<7) | (1<<8));
}
else
{
// 滅燈
*gpbdat |= (1<<5) | (1<<6) | (1<<7) | (1<<8);
}
return 0;
}
static struct file_operations first_drv_fops = {
.owner = THIS_MODULE, /* 這是一個宏，推向編譯模塊時自動創建的__this_module變量 */
.open = first_drv_open,
.write = first_drv_write,
};
int major;
static int first_drv_init(void)
{
major = register_chrdev(0, "first_drv", &first_drv_fops); // 注冊, 告訴內核
firstdrv_class = class_create(THIS_MODULE, "firstdrv");
firstdrv_class_dev = class_device_create(firstdrv_class, NULL, MKDEV(major, 0), NULL, "xyz"); /* /dev/xyz */
gpbcon = (volatile unsigned long *)ioremap(0x56000010, 16); //0x56000010是的GPIOB的
gpbdat = gpbcon + 1;
printk("first_drv_init...\n");
return 0;
}
static void first_drv_exit(void)
{
unregister_chrdev(major, "first_drv"); // 卸載
class_device_unregister(firstdrv_class_dev);
class_destroy(firstdrv_class);
iounmap(gpbcon);
printk("first_drv_exit...\n");
}
module_init(first_drv_init);
module_exit(first_drv_exit);
MODULE_LICENSE("GPL");

復制代碼

以下是測試程序

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
/* firstdrvtest on
* firstdrvtest off
*/
int main(int argc, char **argv)
{
int fd;
int val = 1;
fd = open("/dev/xyz", O_RDWR);
if (fd < 0)
{
printf("can't open!\n");
}
if (argc != 2)
{
printf("Usage :\n");
printf("%s <on|off>\n", argv[0]);
return 0;
}
if (strcmp(argv[1], "on") == 0)
{
val = 1;
}
else
{
val = 0;
}
write(fd, &val, 4);
return 0;
}

復制代碼

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TQ2440開發板 Linux第一個驅動--點燈

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