/*****************************************************************************
;Copyright (C) 2005  Hyesco Technology Co.,Ltd
;Institue of Automation, Chinese Academy of Sciences
;
;WebSite:				www.hyesco.com
;Description: 	Keyboard driver on Linux 
;Date:					2006-11-15		
;Author:				Hyesco			
;E_mail:				Lijg@hyesco.com
*****************************************************************************/

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/fs.h>
#include <linux/poll.h>
#include <linux/slab.h>
#include <linux/ioport.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <asm/irq.h> 				
#include <asm/arch/AT91RM9200_SYS.h>

#include <asm/arch/hardware.h>
#include <linux/types.h>
#include <linux/delay.h>
#include <linux/string.h>
#include <linux/devfs_fs_kernel.h>

//全局變量,常量；
static int major=0;
static char s_name[]="key";

#define U8 unsigned char 
#define U16 unsigned short
#define U32 unsigned int

#define key_buffer_len	10 			//定義鍵盤緩沖區長度
#define KBD_JITTER			2 			//ms
#define QUERY_FREQ  		10 			//jiffer=10ms

struct kbd_info{
	U8 bKeyBuff[key_buffer_len]; 	//retunr key code
	U8 bCount; 										//Key count in buffer
	U8 bStart; 										//start location of key
	wait_queue_head_t key_wait;
	spinlock_t lock; 
};

//*********************************************************
//定義鍵值表，4X4矩陣鍵盤
//*********************************************************
static U8 keytable1[4][4] = {
	{0x11,0x12,0x13,0x14},
	{0x21,0x22,0x23,0x24},
	{0x31,0x32,0x33,0x34},
	{0x41,0x42,0x43,0x44},
};

//*********************************************************
//函數原型
//*********************************************************
void Init_Keyboard(void);
int key_open(struct inode * inode, struct file * filp);
int key_release(struct inode * inode, struct file * filp);
unsigned int key_poll(struct file * filp, struct poll_table_struct * wait);
ssize_t key_read(struct file * filp, char * buf, size_t count, loff_t * l);
void key_run_timer(void);


static struct kbd_info ownkbd_info;
static struct timer_list key_timer;

struct file_operations key_fops = {
		owner:		THIS_MODULE,
		open:			key_open,
		release: 	key_release,
		read:    	key_read,
		poll:    	key_poll,
};


//*********************************************************
//初始化模塊函數；
//*********************************************************
static devfs_handle_t devfs_handle;
int __init KEY1_at91_init(void)
{	
		//unsigned int result = 0;
		
		
		int ret;

		//初始化鍵盤端口；
		Init_Keyboard();
		//注冊模塊；
		if ((ret=devfs_register_chrdev(major,s_name,&key_fops)) < 0)
			{
			printk("\r\n<1>Keyboard Register Fail!\r\n");
			return ret;
			}
		
		//動態分配主設備號；
		if(major == 0)
			major = ret;
		
		//建立設備文件，文件名為：key；
		devfs_handle = devfs_register(NULL, "key",DEVFS_FL_DEFAULT,
			major, 0, S_IFCHR | S_IRUSR | S_IWUSR,&key_fops, NULL);
	
		init_waitqueue_head(&ownkbd_info.key_wait);
		ownkbd_info.bCount=0;
		ownkbd_info.bStart=0;
		
		spin_lock_init(&ownkbd_info.lock);
	
		key_run_timer();
		return 0;
}

//*********************************************************
//鍵盤模塊打開函數；
//*********************************************************
int key_open(struct inode * inode, struct file * filp)
{
		MOD_INC_USE_COUNT;
		return 0;
}

//*********************************************************
//鍵盤模塊釋放函數；
//*********************************************************
int key_release(struct inode * inode,struct file * filp)
{
		MOD_DEC_USE_COUNT;
		return 0;
}

//*********************************************************
//鍵值設置函數；
//*********************************************************
static int KEY_DATA(U8 x) 
{
		int status=-1;
		switch(x)
			{
			case 0:
				//第一行輸出高電平
			  status = AT91_SYS->PIOB_PDSR & (0x1 <<0);
		    break;
			case 1:
			  //第二行輸出高電平
			  status = AT91_SYS->PIOB_PDSR & (0x1 <<1);
		    break;
			case 2:
			 	//第三行輸出高電平
			  status = AT91_SYS->PIOB_PDSR & (0x1 <<2);
		  	break;
			case 3:
			  //第四行輸出高電平
			  status = AT91_SYS->PIOB_PDSR & (0x1 <<3);
		    break;
		    
			default:
				break;
	 		}
		return status;
}		

//*********************************************************
//讀鍵函數；
//*********************************************************
ssize_t key_read(struct file * filp, char * buf, size_t count, loff_t * l)
{
		//Get count keys from keyboard
		U8 bTrueCount=0;
		U8 bTmp=0;
		if ((buf!=NULL) && (count>0) && (ownkbd_info.bCount>0))
				{
				spin_lock(&ownkbd_info.lock);

				bTrueCount=(count>ownkbd_info.bCount) ? ownkbd_info.bCount : count;
				bTmp=ownkbd_info.bStart+bTrueCount;
				if (bTmp<=key_buffer_len)
						copy_to_user(buf, ownkbd_info.bKeyBuff+ownkbd_info.bStart, bTrueCount);
				else
						{
						copy_to_user(buf, ownkbd_info.bKeyBuff+ownkbd_info.bStart, key_buffer_len-ownkbd_info.bStart);
						copy_to_user(buf+key_buffer_len-ownkbd_info.bStart, ownkbd_info.bKeyBuff, bTmp-key_buffer_len);
						}
				ownkbd_info.bCount-=bTrueCount;
				ownkbd_info.bStart+=bTrueCount;
				ownkbd_info.bStart=(ownkbd_info.bStart<key_buffer_len)?ownkbd_info.bStart : (ownkbd_info.bStart-key_buffer_len);

				spin_unlock(&ownkbd_info.lock);
				return bTrueCount;
				}
		return -1;
}

//*********************************************************
//  鍵盤輪詢函數；
//*********************************************************
unsigned int key_poll(struct file * filp, struct poll_table_struct * wait)
{
		//Support select/poll 
		spin_lock(&ownkbd_info.lock);
		poll_wait(filp,&ownkbd_info.key_wait,wait);
		if (ownkbd_info.bCount>0)
				{
				spin_unlock(&ownkbd_info.lock);
				return POLLIN |POLLRDNORM;
				}
		else
				{
				spin_unlock(&ownkbd_info.lock);
				return 0;
				}
}

//*********************************************************
//  鍵掃描函數；
//*********************************************************
int Scan_Keyboard(void)
{
		//keyboard scan main function
		//scan key board to detect if a key down or up
		//the result is stored in ownkbd_info
		unsigned char row=0,col=0;
		unsigned int iScanCode1=0,iScanCode2=0;
		U8 bKeyLocation=0;
		int i;

		spin_lock(&ownkbd_info.lock);
		
		if (ownkbd_info.bCount<key_buffer_len)
			{
			//There are remains in Key buffer, so we continue scaning
			//get the location of the key buffer if a key down/up
			bKeyLocation= ownkbd_info.bStart+ownkbd_info.bCount;
			bKeyLocation=(bKeyLocation<key_buffer_len) ? bKeyLocation : (bKeyLocation-key_buffer_len);
			
			//check key down
			if (KEY_DATA(0)==0)
		  	row=0x0;
			else if (KEY_DATA(1)==0)
				row=0x1;
			else if (KEY_DATA(2)==0)
				row=0x2;
			else if (KEY_DATA(3)==0)
				row=0x3;
			else
				goto end;
		
			//列線全送高電平
    	AT91_SYS->PIOB_SODR |= 0xf0;		//0xfc0;
	
			for(i=0;i<4;i++)	
				{
			 	//PB4~PB7依次送出低電平
			 	AT91_SYS->PIOB_CODR |= (0x10 << i);
			 	if (KEY_DATA(row) == 0)
			 		{
			 		//列值在行值的基礎上加10，便于區別；
					col = i+0xa;				
					iScanCode1 = row | (col<<4) ;
					break ;
			 		}
			 	else if(i == 3)
			 		goto end ;
			 	else
        	AT91_SYS->PIOB_SODR |= (0x10 << i);                                
   			}
		
			mdelay(KBD_JITTER);
			AT91_SYS->PIOB_CODR |=0xf0; 

			//check key down again
			if (KEY_DATA(0)==0)
		  	row=0;
			else if (KEY_DATA(1)==0)
				row=1;
			else if (KEY_DATA(2)==0)
				row=2;
			else if (KEY_DATA(3)==0)
				row=3;
			else
					goto end;	  
	  

      AT91_SYS->PIOB_SODR |= 0xf0;

			for(i=0;i<4;i++)	
			{
			 	//AT91_SYS->PIOB_SODR |= (0x1 << i);
			 	AT91_SYS->PIOB_CODR |= (0x10 << i);
			 	if (KEY_DATA(row) == 0)
			 		{
					col = i+0xa;
					iScanCode2 = row | (col<<4) ;
					break ;
					}
			 	else if(i == 3)
			 		goto end ;
			  else
			 		AT91_SYS->PIOB_CODR |= (0x10 << i);
   		}
		
	   	//鍵確認	
	   	if(iScanCode1 != iScanCode2)
	   	goto end;
	 		
	 		//AT91_SYS->PIOB_CODR |= 0xf;
			AT91_SYS->PIOB_CODR |= 0xf0;
	 
	   	//鍵up
	   	while(KEY_DATA(row)==0);
	 
	   	*(ownkbd_info.bKeyBuff+bKeyLocation)=keytable1[row][col-0xa];
			ownkbd_info.bCount++;
                        
      //DPRINTK("Key up %d\n", *(ownkbd_info.bKeyBuff+bKeyLocation));
		
		}

end:
		spin_unlock(&ownkbd_info.lock);
		AT91_SYS->PIOB_CODR |= 0xf0;
		return 0;
}/*end of scan*/


void key_timeout(unsigned long ptr)
{
    Scan_Keyboard();
	  key_run_timer();
}

void key_run_timer(void)
{
    init_timer(&key_timer);
    key_timer.function = key_timeout;
    key_timer.data = (unsigned long)0;
    key_timer.expires = jiffies + QUERY_FREQ;
    add_timer(&key_timer);
}

//*********************************************************
//  鍵盤端口初始化函數；
//*********************************************************
void Init_Keyboard(void)
{
		//PB7~PB0用作鍵盤端口，PB0～PB3作為行，PB4～PB7作為列；
		
		//使能PB7～PB0的GPIO功能
		//	PB7		PB6		PB5		PB4		PB3		PB2		PB1		PB0
		//	1			1			1			1			1			1			1			1		
		AT91_SYS->PIOB_PER |=0xff; 
		
		
		// PB0~PB3 輸入功能設置;
		// PB0~PB3 enable input;
		AT91_SYS->PIOB_ODR |=0xf; 
		
		// PB0~PB3 enable input filter;
		AT91_SYS->PIOB_IFER |=0xf;
		
		// PB0~PB3 enable Pull up;
		AT91_SYS->PIOB_PPUER |=0xf;	
		
		
		// PB4~PB7 輸出功能設置;
  	// PB4~PB7 enable output;
  	AT91_SYS->PIOB_OER |=0xf0; 
  	
		/* set PB4-7 are 0 */  
  	AT91_SYS->PIOB_CODR |=0xf0;  
  
		/* enable piob clock */
  	AT91_SYS->PMC_PCER =0x1<< AT91C_ID_PIOB;
  	
}

//*********************************************************
//注銷模塊函數；
//*********************************************************
void __exit KEY1_at91_cleanup(void)
{
		int retv;
		del_timer_sync(&key_timer);
		
		//注銷模塊；
		retv=devfs_unregister_chrdev(major,s_name);
		return;
}

module_init(KEY1_at91_init);
module_exit(KEY1_at91_cleanup);

MODULE_AUTHOR("www.hyesco.com");
MODULE_DESCRIPTION("AT91 KEY Driver (AT91_KEY)");
MODULE_LICENSE("GPL");