testled.c

px270平台下的led灯显示驱动源码,通过bc7281键盘芯片来驱动,可以实现四个(可扩展)led数码管的任意显示

#include <linux/config.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>

#include <linux/miscdevice.h>
#include <linux/sched.h>
#include <linux/delay.h>
#include <linux/poll.h>
#include <linux/spinlock.h>
#include <asm/irq.h>
#include <linux/delay.h>

#include <asm/hardware.h>

#define GPIO_11 11
#define GPIO_91 91
#define GPIO_17 17
//--------------------------------------------------------
static void delay(int nu)
{
	int i,j;
	j=nu*20;
	for(i=1;i<j;i++)
	mdelay(50);
}
static void read_GPIO_state(int gpio_port)
{
	if((GPDR(gpio_port)&GPIO_bit(gpio_port)))
		printk("GPIO%d pin's direction is out\n",gpio_port);
	else
		printk("GPIO%d pin's direction is in\n",gpio_port);
	
	if((GPLR(gpio_port)&GPIO_bit(gpio_port)))
		printk("GPIO%d pin's voltage is high\n",gpio_port);
	else
		printk("GPIO%d pin's voltage is low\n",gpio_port);
}
static void GPIO_init(void)
{
	set_GPIO_mode(GPIO_11|GPIO_IN);//dat
	set_GPIO_mode(GPIO_17|GPIO_IN);//key
	set_GPIO_mode(GPIO_91|GPIO_OUT);//clk
}
//the valid moment of a clk is the falling edge,we set the clk pin low first,so while
//calling send_a_clock ,wo get the falling edge immediately, 
static void send_a_clock(int gpio_port)
{
	GPCR(gpio_port)|=GPIO_bit(gpio_port);
	udelay(4);
	GPSR(gpio_port)|=GPIO_bit(gpio_port);
	udelay(3);

}
//GPIO_write_bit send the highest bit of a byte,itcost 3us while is called
static int GPIO_write_bit(int gpio_port,int data_write)
{
	unsigned i,tmp;
	int mask=0x80;
	set_GPIO_mode(GPIO_11|GPIO_OUT);// set dat pin out first
	tmp=data_write;
	tmp&=mask;
	i=tmp;
	if(i)
		GPSR(gpio_port)|=GPIO_bit(gpio_port);//gpio_port pin export 1
	else
		GPCR(gpio_port)|=GPIO_bit(gpio_port);//gpio_port pin export 0
}

static int GPIO_read_bit(int gpio_port)  
{
	set_GPIO_mode(gpio_port|GPIO_IN);//set dat pin in first
	if(GPLR(gpio_port)&GPIO_bit(gpio_port))
		return 1;	
	else
		return 0;
}
static int BC7281_read_reg(int reg_nr)
{
	unsigned long i;
	int reg,data;
	data=0;
	reg=reg_nr;
	reg|=0x80;      //read cmd
//send the cmd byte,the cmd contends register address and r/w bit
	do
	{
		send_a_clock(GPIO_91);
	}
	while((GPLR(GPIO_11)&GPIO_bit(GPIO_11)));//send clks until dat turn to low
	send_a_clock(GPIO_91);
	while(!(GPLR(GPIO_11)&GPIO_bit(GPIO_11)));//when dat turn to low ,we send a clk ,and wait dat turn to 
											 //high (dat pin of 7281 mod  is in )
	for(i=0;i<8;i++)   //send 8 bit
	{
		GPIO_write_bit(GPIO_11, reg);
		reg=reg*2;
		send_a_clock(GPIO_91);
		udelay(5);//the output status should keep for more than 5us,so that 7281can read it
	}
	GPSR(GPIO_11)|=GPIO_bit(GPIO_11);
	set_GPIO_mode(GPIO_11|GPIO_IN);   //set gpio11 direction to in before reading from 7281
//read from reg in bc7281
	send_a_clock(GPIO_91);
	while(GPLR(GPIO_11)&GPIO_bit(GPIO_11));//send only one clk,and wait until dat turn to low
	send_a_clock(GPIO_91);// when dat pin turn to low ,we send a clk,7281 send a bit
	for(i=0;i<8;i++)
	{
		udelay(2);
		data<<1;
		if(GPLR(GPIO_11)&GPIO_bit(GPIO_11))
			data|=0x01;
		send_a_clock(GPIO_91);
		
	}
	return data;
	

}
static int BC7281_write_reg(int reg_nr,int command)
{
	unsigned long i;
	int reg= reg_nr;
	int cmd=command;
//send the cmd byte,the cmd contends register address and r/w bit
	do
	{
		send_a_clock(GPIO_91);
	}
	while((GPLR(GPIO_11)&GPIO_bit(GPIO_11)));//send clks until dat turn to low
	send_a_clock(GPIO_91);
	while(!(GPLR(GPIO_11)&GPIO_bit(GPIO_11)));//when dat turn to low ,we send a clk ,and wait dat turn to 
						                                    //high (dat pin of 7281 mod  is in )
	for(i=0;i<8;i++)	 //send 8 bit
	{
		GPIO_write_bit(GPIO_11, reg);
		reg=reg*2;
		send_a_clock(GPIO_91);
		udelay(5);
	}
	set_GPIO_mode(GPIO_11|GPIO_IN);
//send the data byte,the byte to write to 7281
		do
	{
		send_a_clock(GPIO_91);
	}
	while((GPLR(GPIO_11)&GPIO_bit(GPIO_11)));
	send_a_clock(GPIO_91);
	while(!(GPLR(GPIO_11)&GPIO_bit(GPIO_11)));
	for(i=0;i<8;i++)
	{
		GPIO_write_bit(GPIO_11, cmd);
		cmd=cmd*2;
		send_a_clock(GPIO_91);
		udelay(5);
	}
	set_GPIO_mode(GPIO_11|GPIO_IN);//don't forget wo set gpio11 mod in.
}
static int BC7281_init(void)
{
	int data=0x80;
	int reg=0x12;
	printk("BC7281 init... ...\n");
	BC7281_write_reg(reg, data);//set control reg ,
	BC7281_read_reg(0x13);
}

static int __init LED_init(void)
{
	int i,key;
	int readstate=0;
	printk("module init... ...\n");
	GPIO_init();
	printk("read gpio state after init\n");
	read_GPIO_state(11);
	read_GPIO_state(17);
	read_GPIO_state(91);
	BC7281_init();
	for(i=0;i<1;i++)
	{
	// 0
	BC7281_write_reg(0x00,0xc0);
	//BC7281_write_reg(0x01,0xc0);
	//BC7281_write_reg(0x02,0xc0);
	//BC7281_write_reg(0x03,0xc0);
	delay(1);
	// 1
	//BC7281_write_reg(0x00,0xf9);
	BC7281_write_reg(0x01,0xf9);
	//BC7281_write_reg(0x02,0xf9);
	//BC7281_write_reg(0x03,0xf9);
	delay(1);
	// 2
	//BC7281_write_reg(0x00,0xa4);
	//BC7281_write_reg(0x01,0xa4);
	BC7281_write_reg(0x02,0xa4);
	//BC7281_write_reg(0x03,0xa4);
	delay(1);
	// 3
	//BC7281_write_reg(0x00,0xb0);
	//BC7281_write_reg(0x01,0xb0);
	//BC7281_write_reg(0x02,0xb0);
	BC7281_write_reg(0x03,0xb0);
	delay(1);
	// 4
	/*BC7281_write_reg(0x00,0x99);
	BC7281_write_reg(0x01,0x99);
	BC7281_write_reg(0x02,0x99);
	BC7281_write_reg(0x03,0x99);
	delay(1);
	// 5
	BC7281_write_reg(0x00,0x92);
	BC7281_write_reg(0x01,0x92);
	BC7281_write_reg(0x02,0x92);
	BC7281_write_reg(0x03,0x92);
	delay(1);
	// 6
	BC7281_write_reg(0x00,0x82);
	BC7281_write_reg(0x01,0x82);
	BC7281_write_reg(0x02,0x82);
	BC7281_write_reg(0x03,0x82);
	delay(1);
	// 7
	BC7281_write_reg(0x00,0xf8);
	BC7281_write_reg(0x01,0xf8);
	BC7281_write_reg(0x02,0xf8);
	BC7281_write_reg(0x03,0xf8);
	delay(1);
	// 8
	BC7281_write_reg(0x00,0x80);
	BC7281_write_reg(0x01,0x80);
	BC7281_write_reg(0x02,0x80);
	BC7281_write_reg(0x03,0x80);
	delay(1);
	// 9
	BC7281_write_reg(0x00,0x90);
	BC7281_write_reg(0x01,0x90);
	BC7281_write_reg(0x02,0x90);
	BC7281_write_reg(0x03,0x90);
	delay(1);*/
		}
	BC7281_write_reg(0x12, 0x00);
	BC7281_init();
	key=BC7281_read_reg(0x13);
	printk("the key is:%d",key);
	printk("init over!\n");
	return 0;
}
static void __exit LED_exit(void)
{
	printk("module exit\n");
}
//----------------------------------------------------------
MODULE_AUTHOR("liuxianyu"); 
MODULE_LICENSE("GPL"); 
module_init(LED_init); 
module_exit(LED_exit);