linux-imx

/*

 * ec_sys.c

 *

 * Copyright (C) 2010 SUSE Products GmbH/Novell

 * Author:

 *      Thomas Renninger <trenn@suse.de>

 *

 * This work is licensed under the terms of the GNU GPL, version 2.

 */

​

#include <linux/kernel.h>

#include <linux/acpi.h>

#include <linux/debugfs.h>

#include <linux/module.h>

#include <linux/uaccess.h>

#include "internal.h"

​

MODULE_AUTHOR("Thomas Renninger <trenn@suse.de>");

MODULE_DESCRIPTION("ACPI EC sysfs access driver");

MODULE_LICENSE("GPL");

​

static bool write_support;

module_param(write_support, bool, 0644);

MODULE_PARM_DESC(write_support, "Dangerous, reboot and removal of battery may "

         "be needed.");

​

#define EC_SPACE_SIZE 256

​

static struct dentry *acpi_ec_debugfs_dir;

​

static ssize_t acpi_ec_read_io(struct file *f, char __user *buf,

                   size_t count, loff_t *off)

{

    /* Use this if support reading/writing multiple ECs exists in ec.c:

     * struct acpi_ec *ec = ((struct seq_file *)f->private_data)->private;

     */

    unsigned int size = EC_SPACE_SIZE;

    loff_t init_off = *off;

    int err = 0;

​

    if (*off >= size)

        return 0;

    if (*off + count >= size) {

        size -= *off;

        count = size;

    } else

        size = count;

​

    while (size) {

        u8 byte_read;

        err = ec_read(*off, &byte_read);

        if (err)

            return err;

        if (put_user(byte_read, buf + *off - init_off)) {

            if (*off - init_off)

                return *off - init_off; /* partial read */

            return -EFAULT;

        }

        *off += 1;

        size--;

    }

    return count;

}