arm7(S3C44B0X)数码管驱动程序

 本程序适合基于三星44B0X arm7的开发板。我买的是蓝海微芯的开发板，不过从bios的代码可以看出是仿优龙的。八个数码管(1-8)接在了PCONE I/O口上。能够控制的有1,4-7。
如何在内核源代码树中添加驱动程序和在romfs中添加用户应用程序可以参考前两篇文章，下面只粘贴代码，注释的代码是2.6内核注册字符设备的代码，而我的板子是2.4的内核。
先看一下板子的输出吧：


          ____ _  _
         /  __| ||_|                 
    _   _| |  | | _ ____  _   _  _  _
   | | | | |  | || |  _ /| | | |/ // /
   | |_| | |__| || | | | | |_| |/    /
   |  ___/____|_||_|_| |_|/____|/_//_/
   | |
   |_|

For further information check:
http://www.uclinux.org/



BusyBox v0.60.5 (2007.06.07-12:05+0000) Built-in shell (msh)
Enter 'help' for a list of built-in commands.

# more /proc/sys/kernel/printk
7       4       1       7
# ls -l /dev/led
crw-r--r--    1 root     root     254,   0 Jan 01 00:00 /dev/led
# more /proc/ioports
01d20028-01d20033 : led
06000000-06000ffe : cs8900a
# led
Hey! device opened
Turn off LED1

/dev/led opened, fd=3
Turn off LED4
Turn off LED5
Turn off LED6
Turn off LED7
Turn on LED1
Turn on LED4
Turn on LED5
Turn on LED6
Turn on LED7
Hmmm! device closed
/dev/led closed :)

1. uClinux-dist/linux-2.4.x/drivers/char/led.c

#include <linux/module.h>
#include <linux/config.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/interrupt.h>
#include <linux/errno.h>
#include <linux/ioport.h>
#include <linux/fs.h>

#include <asm/hardware.h>
#include <asm/io.h>
#include <asm/mach/irq.h>
#include <asm/arch/irqs.h>
#include <asm/uaccess.h>
#include <asm/irq.h>

#include "led.h"


MODULE_LICENSE ("GPL");

int led_major = 254;
// int led_minor = 0;
// int number_of_devices = 1;

// struct cdev cdev;
dev_t dev = 0;

static int led_open (struct inode *inode, struct file *file)
{
    printk (KERN_INFO "Hey! device opened/n");
    return 0;
}

static int led_release (struct inode *inode, struct file *file)
{
    printk (KERN_INFO "Hmmm! device closed/n");
    return 0;
}

void led_manager(int arg, int nr)
{
    if (arg == 0) {
        printk (KERN_INFO "Turn on LED%d/n", nr);
        outb(inb(S3C44B0X_PDATE) & ~(1 << (nr - 1)), S3C44B0X_PDATE);
    } else if (arg == 1) {
        printk (KERN_INFO "Turn off LED%d/n", nr);
        outb(inb(S3C44B0X_PDATE) | (1 << (nr - 1)), S3C44B0X_PDATE);
    } else
        printk (KERN_INFO "Wrong arg/n");
}

int led_ioctl (struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg)
{
    int ret = 0;
    int nr = _IOC_NR(cmd);
    led_manager(arg, nr);

//     switch (cmd) {
//     case LED1:
//     led_manager(arg, nr);
//         break;
//
//     case LED4:
//     led_manager(arg, nr);
//         break;
//
//     case LED5:
//     led_manager(arg, nr);
//         break;
//
//     case LED6:
//     led_manager(arg, nr);
//         break;
//
//     case LED7:
//     led_manager(arg, nr);
//         break;
//
//     default:
//         break;
//     }

    return ret;
}

struct file_operations led_fops = {
    .owner = THIS_MODULE,
    .open    = led_open,
    .release = led_release,
    .ioctl = led_ioctl,
};

// static void char_reg_setup_cdev (void)
// {
//     int error, devno = MKDEV (led_major, led_minor);
//     cdev_init (&cdev, &led_fops);
//     cdev.owner = THIS_MODULE;
//     cdev.ops = &led_fops;
//     error = cdev_add (&cdev, devno , 1);
//     if (error)
//         printk (KERN_NOTICE "Error %d adding char_reg_setup_cdev", error);
//
// }

static int __init led_init (void)
{
    int result;

//  dev = MKDEV (led_major, led_minor);
//  result = register_chrdev_region (dev, number_of_devices, "led");
    request_region(S3C44B0X_PCONE, 12, "led");
    result = register_chrdev(led_major, "led", &led_fops);
    if (result<0) {
        printk (KERN_WARNING "led: can't get major number %d/n", led_major);
        return result;
    }
    outl(0x00025569, S3C44B0X_PCONE);
    outb((inl(S3C44B0X_PDATE) & 0x06), S3C44B0X_PDATE);
//  char_reg_setup_cdev ();
    printk (KERN_INFO "led_ioctl driver done/n");
    return 0;
}

static void __exit led_exit (void)
{
//  dev_t devno = MKDEV (led_major, led_minor);
//  cdev_del (&cdev);
//  unregister_chrdev_region (devno, number_of_devices);
    release_region(S3C44B0X_PCONE, 12);
    unregister_chrdev(led_major, "led");
    printk (KERN_INFO "led_ioctl cleaned up/n");
}

module_init (led_init);
module_exit (led_exit);


2. uClinux-dist/linux-2.4.x/drivers/char/led.h

#define LED_MAGIC 'k'

#define LED1 _IO (LED_MAGIC, 1)
#define LED4 _IO (LED_MAGIC, 4)
#define LED5 _IO (LED_MAGIC, 5)
#define LED6 _IO (LED_MAGIC, 6)
#define LED7 _IO (LED_MAGIC, 7)


3. uClinux-dist/user/led/led.c
 
#include <stdio.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include <fcntl.h>

#include "led.h"
#define TURNON    0
#define TURNOFF    1

int main (void)
{
    int fd;
    fd = open ("/dev/led",O_RDWR);
    if (fd < 0) {
      printf ("fd open failed/n");
      exit(0);
    }
    printf ("/n/dev/led opened, fd=%d/n",fd);
    ioctl (fd, LED1, TURNOFF);
    sleep(1);
    ioctl (fd, LED4, TURNOFF);
    sleep(1);
    ioctl (fd, LED5, TURNOFF);
    sleep(1);
    ioctl (fd, LED6, TURNOFF);
    sleep(1);
    ioctl (fd, LED7, TURNOFF);
    sleep(1);

    ioctl (fd, LED1, TURNON);
    sleep(1);
    ioctl (fd, LED4, TURNON);
    sleep(1);
    ioctl (fd, LED5, TURNON);
    sleep(1);
    ioctl (fd, LED6, TURNON);
    sleep(1);
    ioctl (fd, LED7, TURNON);
    sleep(1);

    close (fd);
    printf ("/dev/led closed :)/n");

    return 0;
}