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Date: Sat, 2 Jun 2012 07:50:50 +0530
Message-ID: <CAKB833=F-Tkss-opb62eeF-zdGdXpG_Z=ONRazdGG1-gF1RidQ@mail.gmail.com>
Subject: Need help regarding parallel port interrupt in kernel 3.2
From: Vishal Nandanwar <operational.people@gmail.com>
To: linux-kernel@vger.kernel.org
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Hi,

I am working on a parallel port code, in which I want to achieve the
interrupt on pin 10. I have created a sample circuit as mentioned in
Book LDD. I have connected pin 9 to pin 10 and writing 0x00 and 0xFF
on the port to generate interrupt.

I have created one sample code.

##--------------------------------------------------------------------------------------------------------------------------------
[Code]
#include<linux/init.h>
#include<linux/module.h>
#include<linux/fs.h>
#include<linux/cdev.h>
#include<linux/slab.h>
#include<linux/io.h>
#include<linux/ioport.h>
#include<linux/interrupt.h>
#include<asm/uaccess.h>
#include<asm/irq.h>

#include "parportD.h"

MODULE_LICENSE("Dual BSD/GPL");

int parportD_minor, parportD_major, parportD_count;
struct cdev *parportD_cdev;
dev_t dev = 0;
int flag;
int intID = 3;
int s = 0;
struct resource *res;
unsigned long portID = 0x378;
unsigned long length = 0x08;

struct file_operations cDevice_fops = {
? ? ? ?.owner = THIS_MODULE,
? ? ? ?.read = parportD_read,
? ? ? ?.write = parportD_write,
? ? ? ?.open = parportD_open,
? ? ? ?.release = parportD_release,
};

irqreturn_t intHandle(int irq, void *dev_id)
{
? ? ? ?printk("Interrupt occured.");
? ? ? ?s = 1;
? ? ? ?outb_p(0x00, portID + 2);
? ? ? ?outb_p(0x10, portID + 2);


? ? ? ?return IRQ_HANDLED;
}

static int parportD_init(void) {

? ? ? ?int retVal, err;

? ? ? ?printk("parportD initialization started.\n");

? ? ? ?parportD_count = 0x01;
? ? ? ?parportD_minor = 0x00;

/* ? ? ?res = request_region(portID, length ,"parportD");
? ? ? ?if (res == NULL) {
? ? ? ? ? ? ? ?printk(KERN_NOTICE "Port allocation failed.");
? ? ? ? ? ? ? ?return -1;
? ? ? ?}*/

? ? ? ?retVal = alloc_chrdev_region(&dev, parportD_minor, 1, "parportD");
? ? ? ?if (retVal != 0x00) {
? ? ? ? ? ? ? ?printk(KERN_NOTICE "chrdev region allocation failed.");
? ? ? ? ? ? ? ?return -1;
? ? ? ?}

? ? ? ?parportD_major = MAJOR(dev);
? ? ? ?parportD_minor = MINOR(dev);

? ? ? ?printk("retVal = %d\n", retVal);
? ? ? ?printk("Major number = %d\n", parportD_major);
? ? ? ?printk("Minor number = %d\n", parportD_minor);
? ? ? ?printk("Device count = %d\n", parportD_count);

? ? ? ?parportD_cdev = cdev_alloc();

? ? ? ?cdev_init(parportD_cdev, &cDevice_fops);
? ? ? ?parportD_cdev->owner = THIS_MODULE;
? ? ? ?err = cdev_add(parportD_cdev, dev, 1);
? ? ? ?if (err < 0) {
? ? ? ? ? ? ? ?printk(KERN_NOTICE "Error %d adding parportD", err);
? ? ? ?} else {
? ? ? ? ? ? ? ?printk("parportD initialization completed.\n");
? ? ? ?}

? ? ? ?//request IRQ
? ? ? ?retVal = request_irq(intID, intHandle, IRQF_DISABLED, "parportD", NULL);

? ? ? ?printk("Interrupt request return value = %d\n", retVal);

? ? ? ?if (retVal ) {
? ? ? ? ? ?printk("Interrupt request failed. = %d\n", retVal);
? ? ? ?} else {
? ? ? ? ?//enable intrrupts
? ? ? ? ?outb(0x10, portID+2);
? ? ? ? ? printk("Interrupt enabled.\n");
? ? ? ?}

? ? ? ?return 0;
}

static void parportD_exit(void) {
? ? ? ?printk("parportD exit started.\n");
? ? ? ?cdev_del(parportD_cdev);
? ? ? ?free_irq(intID, NULL);
? ? ? ?release_region(0x378, 8);

? ? ? ?printk("parportD exit completed.\n");
}

int parportD_open(struct inode *inode, struct file *filep) {
? ? ? ?int retVal = 0x00;
? ? ? ?printk("parportD opend.\n");

? ? ? ?return retVal;
}

int parportD_release(struct inode *inode, struct file *filep) {
? ? ? ?printk("\nparportD released.\n");
? ? ? ?return 0x00;
}

ssize_t parportD_read(struct file *filep, char *buf, size_t count,
loff_t *f_pos) {
? ? ? ?/*ssize_t retVal = 0x00;
? ? ? ?printk("Device read received.\n");

? ? ? ?retVal = copy_to_user((void *)buf, (void*)data, count);
? ? ? ?printk("Device read = %s ratVal = %d count = %d \n", buf,
retVal, count);*/

? ? ? ?return count;
}

ssize_t parportD_write(struct file *filep, const char *buf, size_t
count, loff_t *f_pos) {
? ? ? ?printk("Device write received.\n");
? ? ? ?printk("s = %d\n", s);

? ? ? ?if(flag == 0) {
? ? ? ? ? ? ? ?flag = 1;
? ? ? ? ? ? ? ?outb(0, portID);
? ? ? ? ? ? ? ?printk("Wrote 0 on port. \n");
? ? ? ?} else {
? ? ? ? ? ? ? ?flag = 0;
? ? ? ? ? ? ? ?outb(255, portID);
? ? ? ? ? ? ? ?printk("Wrote 255 on port. \n");
? ? ? ?}

? ? ? ?printk("Data received = %s", buf);

? ? ? ?return count;
}

module_init(parportD_init);
module_exit(parportD_exit);
[/Code]
##------------------------------------------------------------------------------------------------------------------------------

Problem here is, I am not getting interrupt or my interrupt handler is
not executing. I wonder do we need to do any setting in BIOS for this
interrupt? Or do we need to enable any flag during kernel compilation?

Vishal N
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