Read key value Driver

#include <linux/module.h>

#include <linux/kernel.h>

#include <linux/fs.h>

#include <linux/init.h>

#include <linux/delay.h>

#include <asm/uaccess.h>

#include <asm/irq.h>

#include <asm/io.h>

#include <asm/arch/regs-gpio.h>

#include <asm/hardware.h>

static struct class *seconddrv_class;

static struct Class_device *seconddrv_class_dev;

volatile unsigned long *gpfcon;

volatile unsigned long *gpfdat;

volatile unsigned long *gpgcon;

volatile unsigned long *gpgdat;

static int Second_drv_open (struct inode *inode, struct file *file) {

/* Configure gpf0,2 as input pin

*/ *

Gpgcon &=~ ((0x3<< (0*2)) | (0x3<< (2*2)));

/* Configure gpf3,11 as input pin */

*gpfcon &=~ ((0x3<< (3*2)) | (0x3<< (11*2)));

return 0;

}

ssize_t second_drv_read (struct file *file, char __user *buf, size_t size, loff_t *ppos) {

/* Returns the level of four pins */

unsigned char key_vals[4];

int regval;

if (Size! = sizeof (key_vals))

Return-einval;

/* Read gpf0,2*/

Regval= *gpfdat;

Key_vals [0]= (Regval & (1<<0))? 1:0;

Key_vals [1]= (Regval & (1<<2))? 1:0;

/* Read gpf3,11*/

Regval= *gpgdat;

Key_vals [2]= (Regval & (1<<3))? 1:0;

Key_vals [3]= (Regval & (1<<11))? 1:0;

Copy_to_user (buf, key_vals, sizeof (key_vals));

return sizeof (key_vals);

}

static struct file_operations second_drv_fops= {

. Owner=this_module,

. open = Second_drv_open,

. read= Second_drv_read,};

int major;

static int Second_drv_init () {

Major=register_chrdev (0, "Second_drv", & Second_drv_fops);

Seconddrv_class = Class_create (This_module, "seconddrv");

/*if (Is_err (Firstdrv_class))

Return Ptr_err (Firstdrv_class); */

seconddrv_class_dev= class_device_create (Seconddrv_class, NULL, MKDEV (major, 0), NULL, "buttons");

/*if (Unlikely (Is_err (Firstdrv_class_dev)))

Return Ptr_err (FIRSTDRV_CLASS_DEV); */

Gpfcon = (volatile unsigned long *) Ioremap (0x56000050,16);

gpfdat=gpfcon+1;

Gpgcon = (volatile unsigned long *) Ioremap (0x56000060,16);

gpgdat=gpgcon+1;

return 0;

}

static void Second_drv_exit () {

Unregister_chrdev (Major, "second_drv");

Class_device_unregister (Seconddrv_class_dev);

Class_destroy (Seconddrv_class);

Iounmap (Gpfcon);

Iounmap (Gpgcon);

return 0;

}

Module_init (Second_drv_init);

Module_exit (Second_drv_exit);

Module_license ("GPL");

Read key value Driver