led.c

基于AT91RM9200 板卡的OLED Linux 驱动程序

/* 
 * led EBI interface for Linux on Atmel AT91RM9200
 * Copyright (c) 2006 Ligang Wang
 * [e-mail]
 */

/* include some file */ 
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/ioport.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/poll.h>
#include <linux/init.h>
#include <asm/io.h>
#include <asm/system.h>
#include <asm/arch/hardware.h>
#include <asm/segment.h>

//#include "led.h"

/* define some macro for this module*/

#define DEV_MEM_SIZE 	8		//define memory size for device
#define DEV_MAJOR		250   		//major of led
#define LED_PHY_ADDR	0x80000000


static AT91PS_SYS AT91_SYS1 = (AT91PS_SYS) AT91C_VA_BASE_SYS;

static void * led_vit_addr;
/*
 * Read funcation for vfs
 */
ssize_t at91_led_read(struct file * file, char *buf, size_t count, loff_t * ppos)
{
	return 0;
}

/*
 * Write funcation for vfs
 */
ssize_t at91_led_write(struct file * file, const char * buf, size_t count, loff_t * ppos)
{
	char tmp_data[2];
	char * port;
	int retval = 0;
	retval = copy_from_user((char *)tmp_data,buf,sizeof(unsigned char)*2);
	if (retval)
		return retval;
	if(tmp_data[0] == 0)
		port = (char *)led_vit_addr;
	else
		port = (char *)(led_vit_addr+1);
		
	*port = tmp_data[1];
	return 0;
}		

/* open a device */
static int at91_led_open(struct inode* inode,struct file* file)
{
	MOD_INC_USE_COUNT;
	return 0;	
}

/*
 * Handle commands from user-space.
 */
static int at91_led_ioctl(struct inode *inode, struct file *file,
		unsigned int cmd, unsigned long arg)
{
		return 0;		
}


/*
 * setup led hardware
 */
	
static void at91_led_setup(void)
{
	//Setup bus access time width.
	AT91_SYS1->EBI_SMC2_CSR[7] = (AT91C_SMC2_NWS & 0x8) | AT91C_SMC2_WSEN
									| (AT91C_SMC2_TDF & 0x300) | AT91C_SMC2_BAT | AT91C_SMC2_DBW_8;

}

static int at91_led_release(struct inode* inode,struct file* file)
{
	MOD_DEC_USE_COUNT;
	return 0;
}

struct file_operations at91_led_fops = {
	owner:       THIS_MODULE,
	write:		at91_led_write,
	read:			at91_led_read,
	open:     at91_led_open,
	ioctl:		at91_led_ioctl,
	release:  at91_led_release,
};


/*
 * Initialize and install led driver
 */

static int __init at91_led_init(void)
{

	at91_led_setup();
	
	led_vit_addr = (unsigned long)(ioremap(LED_PHY_ADDR, DEV_MEM_SIZE));
	if (check_region(led_vit_addr, DEV_MEM_SIZE)<0) 
		return -1; 
	request_region(led_vit_addr, DEV_MEM_SIZE,"led");
	
	if(register_chrdev(DEV_MAJOR,"led",&at91_led_fops))
	{
		printk("LED: Can not register led driver \n");
		return -1;
	}
	printk("led: the led is working now\n");
	return 0;
}

/*
 * Disable and remove the led driver
 */
static void __exit at91_led_exit(void)
{
	printk("led: at91_led_exit has been called\n");
	unregister_chrdev(DEV_MAJOR,"led");
	iounmap(led_vit_addr);
	return;
}

module_init(at91_led_init);
module_exit(at91_led_exit);

MODULE_AUTHOR("Ligang Wang");
MODULE_DESCRIPTION("AT91 rm9200 led driver");
MODULE_LICENSE("GPL");