[字符设备]led驱动(定时器)

练习定时器
--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 <linux/timer.h>
#include <linux/types.h>
#include <asm/io.h>
#include <asm/module.h>
#include <asm/uaccess.h>
#include <mach/regs-gpio.h>
#include <mach/hardware.h>


#define DEVICE_NAME "leds"
#define LEDDEV_MAJOR 0
#define LED_NR_DEVS  1
#define LEDON  0
#define LEDOFF 1

struct led_dev
{
    struct cdev dev;
    atomic_t index;
    struct timer_list timer;
};
struct led_dev *devp;
struct class *my_class;

static int led_major = LEDDEV_MAJOR;

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 void s3c2440_timer_handle(unsigned long arg)
{
    int i;
    mod_timer(&devp->timer, jiffies + HZ);
    atomic_inc(&devp->index);
    i = devp->index.counter;
    if (atomic_sub_and_test(4, &devp->index))
        atomic_set(&devp->index, 0);
    else
        atomic_set(&devp->index, i);

    for (i = 0; i < 4; ++i)
        s3c2410_gpio_setpin(led_table[i], 1);
    s3c2410_gpio_setpin(led_table[devp->index.counter], 0);
}

static int s3c2440_leds_open(struct inode *inode, struct file *filp)
{
    int i;
    for(i = 0; i < 4; ++i)
    {
        s3c2410_gpio_cfgpin(led_table[i], led_cfg_table[i]);
        s3c2410_gpio_setpin(led_table[i], 1);
    }
    init_timer(&devp->timer);
    devp->timer.function = &s3c2440_timer_handle;
    devp->timer.expires = jiffies + HZ;

    add_timer(&devp->timer);
    atomic_set(&devp->index, 0);
    return 0;
}


static int s3c2440_leds_release(struct inode *inode, struct file *filp)
{
    del_timer(&devp->timer);
    return 0;
}

static struct file_operations dev_fops =
{
    .owner = THIS_MODULE,
    .open  = s3c2440_leds_open,
    .release = s3c2440_leds_release,
};


static int __init s3c2440_led_init(void)
{
    int result;
    struct device *devxx;
    dev_t devno = MKDEV(led_major, 0);

    if (led_major)
        result = register_chrdev_region(devno, 1, DEVICE_NAME);
    else
    {
        result = alloc_chrdev_region(&devno, 0, 1, DEVICE_NAME);
        led_major = MAJOR(devno);
        printk("Major-->%d\n", led_major);
    }

    if (result < 0)
        return result;

    devp = kmalloc(sizeof(struct led_dev), GFP_KERNEL);
    if (!devp)
    {
        result = -ENOMEM;
        goto fail_malloc;
    }

    cdev_init(&devp->dev, &dev_fops);
    devp->dev.owner = THIS_MODULE;
    devp->dev.ops = &dev_fops;

    cdev_add(&devp->dev, devno, LED_NR_DEVS);

    my_class = class_create(THIS_MODULE, "my_class");
    if (IS_ERR(my_class))
        return -1;
    devxx = device_create(my_class, NULL, devno, NULL, DEVICE_NAME);
    if (IS_ERR(devxx))
    {
        printk("create device node fail!\n");
        return -1;
    }
    printk("create device node sucess!\n");
    return 0;

fail_malloc:
    unregister_chrdev_region(MKDEV(led_major, 0), LED_NR_DEVS);
    return result;
}

static void __exit s3c2440_led_exit(void)
{
    cdev_del(&devp->dev);
    device_destroy(my_class, MKDEV(led_major, 0));
    class_destroy(my_class);
    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);

--app-led.c

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

int main(int argc, char **argv)
{
    int fd;
    fd = open("/dev/leds", 0);
    while(1);
}

--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 app
sub:
    cp $(TFILE) ../rootfs
clean:
    rm -f *.ko *.o *.mod.o *.mod.c *.symvers  modul*

endif