lcd_driver.c

做好的基于arm的lcd 的驱动程序

#include <linux/module.h>
#include <linux/fs.h>
#include <asm/io.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <asm/uaccess.h>
#include <linux/errno.h>
#include <linux/types.h>

MODULE_LICENSE("GPL");

unsigned int  lcd_major = 0;


static int open_lcd(struct inode *, struct file *);
static ssize_t read_lcd(struct file *, char *, size_t , loff_t *);
static int ioctl_lcd(struct inode *, struct file *, unsigned int cmd, unsigned long);
static ssize_t write_lcd(struct file *, const char *, size_t, loff_t *);
static int close_lcd(struct inode *, struct file *);
static void delay();

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

static ssize_t read_lcd(struct file *file, char *buf, size_t len, loff_t *off)
{
    return 0;
}

static ssize_t write_lcd(struct file *file, const char *buf, size_t len, loff_t *off)
{
    unsigned char *lcd_data_addr;
    unsigned char data;
    lcd_data_addr = ioremap((unsigned long)0x30000000, (unsigned long)1);
    data = *buf;
    writeb(data, lcd_data_addr);
    iounmap((void *)lcd_data_addr);
    return *off;
}
static int ioctl_lcd(struct inode *inode, struct file *file, 
	unsigned int cmd, unsigned long arg)
{
    unsigned char *lcd_row_addr;
    unsigned char *lcd_list_addr;
    unsigned char *lcd_control_addr;
    unsigned char *lcd_data_addr;
    unsigned char ctrl;
    unsigned char row;
    unsigned char list;
    unsigned char data;
    int i, j;
    lcd_control_addr = ioremap((unsigned long)0x3000000c, (unsigned long)1);
    lcd_row_addr = ioremap((unsigned long)0x30000004, (unsigned long)1);
    lcd_list_addr = ioremap((unsigned long)0x30000008, (unsigned long)1);
    lcd_data_addr = ioremap((unsigned long)0x30000000, (unsigned long)1);

    switch(cmd)
    {
	case 1:
	    //printk("before ctrl=0x%x\n", ctrl);
	    copy_from_user(&ctrl, (unsigned char *)arg, sizeof(unsigned char));
	    //printk("ofter ctrl=0x%x\n", ctrl);
	    writeb(ctrl, lcd_control_addr);
	    delay();
	    break;
	case 2:
	    copy_from_user(&row, (unsigned char *)arg, sizeof(unsigned char));
	    writeb(row, lcd_row_addr);
	    delay();
	    break;
	case 3:
	    copy_from_user(&list, (unsigned char *)arg, sizeof(unsigned char));
	    writeb(list, lcd_list_addr);
	    delay();
	    break;
	case 4:
	    copy_from_user(&data, (unsigned char *)arg, sizeof(unsigned char));
	    //printk("kernel data=0x%x\n", data);
	    for(i = 0; i < 234; i++)
	    {
		writeb(row, lcd_row_addr);
		delay();
		writeb(list, lcd_list_addr);
		delay();
		writeb(list, lcd_list_addr);
		delay();
		for(j = 0; j < 320; j++)
		{
		    writeb(data, lcd_data_addr);
		    delay();
		}
		row = row + 0x01;
	    }
    }	
    iounmap((void *)lcd_control_addr);
    iounmap((void *)lcd_row_addr);
    iounmap((void *)lcd_list_addr);
    iounmap((void *)lcd_data_addr);
    return - ENOTTY;
}

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

struct file_operations lcd_fops =
{
	open:open_lcd,
	read:read_lcd,
	write:write_lcd,
	ioctl:ioctl_lcd,
	release:close_lcd,
};

int init_module(void)
{

    int ret;
    ret = register_chrdev(lcd_major, "lcd", &lcd_fops);
    if(ret < 0) 
    {
	printk("lcd register error\n !!!");
	return ret;
    }
    else
    {
	if(lcd_major == 0)
	{
	    lcd_major = ret;
	    printk("lcd register success,lcd major is %d !!!\n", ret);
	}
	else
	{
	    printk("lcd register success,lcd major is %d !!!\n", lcd_major); 
	}
    }
    return 0;
}

void cleanup_module(void)
{
    int ret;
    ret = unregister_chrdev(lcd_major, "lcd");
    if (ret < 0)
    {
	printk("test_var unregister failure !!!\n");
    }
    else    
    {
	printk("test_var unregister success!!!\n");
    }
}

void delay() 
{
    int i,j;
    for(i=0;i<=1;i++)
	for(j=0;j<=100;j++)
	{       
	    ;
	}
}