[字符设备]led次设备实现

--led.c

#include <linux/module.h>
#include <linux/types.h>
#include <linux/fs.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/cdev.h>
#include <linux/device.h>
#include <linux/gpio.h>
#include <asm/io.h>
#include <asm/module.h>
#include <asm/uaccess.h>
#include <mach/regs-gpio.h>
#include <mach/hardware.h>


#include "leddev.h"
#define DEVICE_NAME "led"
#define LEDDEV_MAJOR 0
#define LED_NR_DEVS  4
#define LEDON  0
#define LEDOFF 1

struct cdev *devp;

static int led_major = LEDDEV_MAJOR;

static struct class *led_class[LED_NR_DEVS];

static unsigned long led_table[] =
{
    S3C2410_GPB(5),
    S3C2410_GPB(6),
    S3C2410_GPB(7),
    S3C2410_GPB(8),
};

static unsigned int led_cfg_table[] =
{
    S3C2410_GPIO_OUTPUT,
    S3C2410_GPIO_OUTPUT,
    S3C2410_GPIO_OUTPUT,
    S3C2410_GPIO_OUTPUT,
};

static int s3c2440_leds_open(struct inode *inode, struct file *filp)
{
    int i = iminor(inode);
    filp->private_data = inode->i_cdev;
    s3c2410_gpio_cfgpin(led_table[i], led_cfg_table[i]);
    s3c2410_gpio_setpin(led_table[i], 0);
    return 0;
}

static int s3c2440_leds_ioctl(struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg)
{
    struct cdev *dev = filp->private_data;
    switch(cmd)
    {
        case LEDDEV_ON:
            s3c2410_gpio_setpin(led_table[MINOR(dev->dev)], LEDON);
            break;
        case LEDDEV_OFF:
            s3c2410_gpio_setpin(led_table[MINOR(dev->dev)], LEDOFF);
            break;
        default:
            return -EINVAL;
    }
    return 0;
}

static struct file_operations dev_fops =
{
    .owner = THIS_MODULE,
    .ioctl = s3c2440_leds_ioctl,
    .open  = s3c2440_leds_open,
};

static void s3c2440_led_setup_cdev(struct cdev *dev, int index)
{
    int err, devno = MKDEV(led_major, index);

    cdev_init(dev, &dev_fops);
    dev->owner = THIS_MODULE;
    err = cdev_add(dev, devno, 1);
    if (err)
        printk("Error %d adding LED%d", err, index);
}

static int s3c2440_led_setup_device(int index)
{
    int devno = MKDEV(led_major, index);
    char buf[100];
    memset(buf, 0, 100);
    sprintf(buf, "key_class%d", index);
    led_class[index] = class_create(THIS_MODULE, buf);
    if (IS_ERR(led_class[index]))
        return -1;
    device_create(led_class[index], NULL, devno, NULL, "%s%d", DEVICE_NAME, index);
    return 0;
}

static int __init s3c2440_led_init(void)
{
    int result, i;
    dev_t devno = MKDEV(led_major, 0);

    if (led_major)
        result = register_chrdev_region(devno, LED_NR_DEVS, DEVICE_NAME);
    else
    {
        result = alloc_chrdev_region(&devno, 0, LED_NR_DEVS, DEVICE_NAME);
        led_major = MAJOR(devno);
        printk("Major-->%d\n", led_major);
    }

    if (result < 0)
        return result;

    devp = kmalloc(LED_NR_DEVS * sizeof(struct cdev), GFP_KERNEL);

    for (i = 0; i < LED_NR_DEVS; ++i)
    {
        s3c2440_led_setup_cdev(&devp[i], i);
        s3c2440_led_setup_device(i);
    }

    return result;
}

static void __exit s3c2440_led_exit(void)
{
    int i;
    for (i = 0; i < LED_NR_DEVS; ++i)
    {
        cdev_del(&devp[i]);
        device_destroy(led_class[i], MKDEV(led_major, i));
        class_destroy(led_class[i]);
    }
    unregister_chrdev_region(MKDEV(led_major, 0), LED_NR_DEVS);
}

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Domod");
module_init(s3c2440_led_init);
module_exit(s3c2440_led_exit);

--leddev.h

#ifndef __LEDDEV_H__
#define __LEDDEV_H__

#include
#define LEDDEV_IOC_MAGIC 'l'

#define LEDDEV_ON  _IO(LEDDEV_IOC_MAGIC, 1)
#define LEDDEV_OFF _IO(LEDDEV_IOC_MAGIC, 2)

#define LEDDEV_IOC_MAXNR 2

#endif

--app-led.c
这部分有应付得嫌疑 ^_^

#include "leddev.h"
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <string.h>

int main(int argc, char **argv)
{
    int i, on, led_no;
    int fd[4];
    char buf[100];
    memset(buf, 0, 100);

    if (argc == 2)
    {
        for (i = 0; i < 4; ++i)
        {
            memset(buf, 0, 100);
            sprintf(buf, "/dev/led%d", i);
            fd[i] = open(buf, 0);
            if (fd[i] < 0)
            {
                perror("open device leds");
                exit(1);
            }
            if (sscanf(argv[1], "%d", &on) == 1 && on == 1)
                ioctl(fd[i], LEDDEV_ON, 0);
            if (sscanf(argv[1], "%d", &on) == 1 && on == 0)
                ioctl(fd[i], LEDDEV_OFF, 0);
        }
    }
    if (argc == 3)
    {
        sscanf(argv[1], "%d", &led_no);
        sscanf(argv[2], "%d", &on);
        sprintf(buf, "/dev/led%d", led_no);
        fd[led_no] = open(buf, 0);
        if (on)
            ioctl(fd[led_no], LEDDEV_ON, 0);
        else
            ioctl(fd[led_no], LEDDEV_OFF, 0);
    }

    for (i = 0; i < 4; ++i)
    {
        if (fd[i] >= 0)
            close(fd[i]);
    }
    return 0;

}

--Makefile

CFILE=app-led.c
TFILE=led.ko
ifneq ($(KERNELRELEASE),)

obj-m := led.o

else

KDIR := /home/domod/arm/kernel/src/linux-2.6.32.2
all:
make -C $(KDIR) M=$(PWD) modules ARCH=arm CROSS_COMPILE=arm-linux-
app:
arm-linux-gcc $(CFILE) -o key
sub:
cp $(TFILE) ../rootfs
clean:
rm -f *.ko *.o *.mod.o *.mod.c *.symvers  modul*

endif