Android 驱动编写LED-NDK程序

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <linux/cdev.h>


MODULE_LICENSE("GPL");

#define GPM4CON 0X110002E0
#define GPM4DAT 0X110002E4

#define LED_ON _IOW(‘G‘,0,int)

#define LED_OFF _IOW(‘G‘,1,int)

static struct cdev dev;//1.1 分配cdev结构

static dev_t dev_no;
struct class *led_class;

static unsigned int *led_con;
static unsigned int *led_dat;

long led_ioctl( struct file *file, unsigned int cmd, unsigned long arg )
{
  switch( cmd )
  {
    case LED_ON:
      writel((readl(led_dat)&(~(0x1<<(arg-1)))),led_dat);
      break;

    case LED_OFF:
      writel( (readl(led_dat)|(0x1<<(arg-1))),led_dat);
      break;

    default: 
      return -EINVAL;    
      break;
  }
  return 0;
}

struct file_operations led_fops = {
  .owner = THIS_MODULE,
  .unlocked_ioctl = led_ioctl,
};


static void hw_init()
{
  
  //初始化GPIO控制寄存器
  led_con = ioremap( GPM4CON, 4 );  //地址映射
  led_dat = ioremap( GPM4DAT, 4 );
  writel((readl(led_con)&~0xffff)|0x1111,led_con);  
  writel(readl(led_dat)|0xf,led_dat);  
  
}

static int led_init()
{
  
  //1.2 初始化cdev结构
  alloc_chrdev_region( &dev_no, 0, 1, "my_led" );
  cdev_init( &dev, &led_fops );  
  dev.owner = THIS_MODULE;
  //1.3 注册cdev结构
  cdev_add( &dev, dev_no, 1 );
  //2.硬件初始化
  hw_init();
  //3.创建设备文件
  led_class = class_create(THIS_MODULE,"my_led");        //创建设备类
  device_create( led_class, NULL, dev_no,NULL,"%s","my_led");

  printk("init led device ok!\n");

  return 0;
}

void led_exit()
{
  device_destroy(led_class,dev_no);
  class_destroy(led_class);

  iounmap(led_con);
  iounmap(led_dat);

  cdev_del(&dev);
  unregister_chrdev_region(dev_no,1);
}

module_init( led_init );
module_exit( led_exit );

LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE := ndk_test_myled
LOCAL_SRC_FILES := ndk_led.c
include $(BUILD_SHARED_LIBRARY)