s3c6410字符设备（一）led字符驱动与测试程序

在前面gpio编程中已经写过led灯控制程序，那么现在写字符设备将变得简单许多，而且有更高级的函数让我们调用。

1.测试程序

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

int main(int argc, char **argv)
{
        int on;
        int led_no;
        int fd;

        if (argc != 3 || sscanf(argv[1], "%d", &led_no) != 1 || sscanf(argv[2],"%d", &on) != 1 ||
                        on < 0 || on > 1 || led_no < 0 || led_no > 3) {
                fprintf(stderr, "Usage: leds led_no 0|1\n");
                exit(1);
        }

        fd = open("/dev/leds0", 0); //打开设备文件
        if (fd < 0) {
                fd = open("/dev/leds", 0);
        }
        if (fd < 0) {
                perror("open device leds");
                exit(1);
        }

        ioctl(fd, on, led_no); //使用ioctl控制led
        close(fd);

        return 0;
}

2.驱动程序

#include <linux/miscdevice.h>
#include <linux/delay.h>
#include <asm/irq.h>
//#include <mach/regs-gpio.h>
#include <mach/hardware.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/types.h>
#include <linux/delay.h>
#include <linux/moduleparam.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/ioctl.h>
#include <linux/cdev.h>
#include <linux/string.h>
#include <linux/list.h>
#include <linux/pci.h>
#include <asm/uaccess.h>
#include <asm/atomic.h>
#include <asm/unistd.h>

#include <mach/map.h>
#include <mach/regs-clock.h>
#include <mach/regs-gpio.h>

#include <plat/gpio-cfg.h>
#include <mach/gpio-bank-e.h>
#include <mach/gpio-bank-k.h>

#define DEVICE_NAME "leds"

static long sbc2440_leds_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
switch(cmd) {
unsigned tmp;
case 0:
case 1:
if (arg > 4) {
return -EINVAL;
}
tmp = readl(S3C64XX_GPKDAT); //从内存映射的i/o空间读取32位数据
tmp &= ~(1 << (4 + arg));
tmp |= ( (!cmd) << (4 + arg) );
writel(tmp, S3C64XX_GPKDAT); //向i/o地址写入32位数据
//printk (DEVICE_NAME": %d %d\n", arg, cmd);
return 0;
default:
return -EINVAL;
}
}

static struct file_operations dev_fops = {
.owner= THIS_MODULE,
.unlocked_ioctl= sbc2440_leds_ioctl,
};

static struct miscdevice misc = {
.minor = MISC_DYNAMIC_MINOR,
.name = DEVICE_NAME,
.fops = &dev_fops,
};

static int __init dev_init(void)
{
int ret;

{
unsigned tmp;
tmp = readl(S3C64XX_GPKCON);
tmp = (tmp & ~(0xffffU<<16))|(0x1111U<<16);
writel(tmp, S3C64XX_GPKCON); //初始化控制寄存器

tmp = readl(S3C64XX_GPKDAT);
tmp |= (0xF << 4);
writel(tmp, S3C64XX_GPKDAT); //初始化数据寄存器
}

ret = misc_register(&misc); //注册主设备号为10的特殊字符设备

printk (DEVICE_NAME"\tinitialized\n");

return ret;
}

static void __exit dev_exit(void)
{
misc_deregister(&misc);
}

module_init(dev_init);
module_exit(dev_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("FriendlyARM Inc.");