ec_sys.c

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/*
 * ec_sys.c
 *
 * Copyright (C) 2010 SUSE Products GmbH/Novell
 * Author:
 *      Thomas Renninger <[email protected]>
 *
 * 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 "internal.h"

MODULE_AUTHOR("Thomas Renninger <[email protected]>");
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;
    u8 *data = (u8 *) buf;
    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) {
        err = ec_read(*off, &data[*off - init_off]);
        if (err)
            return err;
        *off += 1;
        size--;
    }
    return count;
}

static ssize_t acpi_ec_write_io(struct file *f, const 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 = count;
    loff_t init_off = *off;
    u8 *data = (u8 *) buf;
    int err = 0;

    if (*off >= EC_SPACE_SIZE)
        return 0;
    if (*off + count >= EC_SPACE_SIZE) {
        size = EC_SPACE_SIZE - *off;
        count = size;
    }

    while (size) {
        u8 byte_write = data[*off - init_off];
        err = ec_write(*off, byte_write);
        if (err)
            return err;

        *off += 1;
        size--;
    }
    return count;
}

static const struct file_operations acpi_ec_io_ops = {
    .owner = THIS_MODULE,
    .open  = simple_open,
    .read  = acpi_ec_read_io,
    .write = acpi_ec_write_io,
    .llseek = default_llseek,
};

int acpi_ec_add_debugfs(struct acpi_ec *ec, unsigned int ec_device_count)
{
    struct dentry *dev_dir;
    char name[64];
    umode_t mode = 0400;

    if (ec_device_count == 0) {
        acpi_ec_debugfs_dir = debugfs_create_dir("ec", NULL);
        if (!acpi_ec_debugfs_dir)
            return -ENOMEM;
    }

    sprintf(name, "ec%u", ec_device_count);
    dev_dir = debugfs_create_dir(name, acpi_ec_debugfs_dir);
    if (!dev_dir) {
        if (ec_device_count != 0)
            goto error;
        return -ENOMEM;
    }

    if (!debugfs_create_x32("gpe", 0444, dev_dir, (u32 *)&first_ec->gpe))
        goto error;
    if (!debugfs_create_bool("use_global_lock", 0444, dev_dir,
                 (u32 *)&first_ec->global_lock))
        goto error;

    if (write_support)
        mode = 0600;
    if (!debugfs_create_file("io", mode, dev_dir, ec, &acpi_ec_io_ops))
        goto error;

    return 0;

error:
    debugfs_remove_recursive(acpi_ec_debugfs_dir);
    return -ENOMEM;
}

static int __init acpi_ec_sys_init(void)
{
    int err = 0;
    if (first_ec)
        err = acpi_ec_add_debugfs(first_ec, 0);
    else
        err = -ENODEV;
    return err;
}

static void __exit acpi_ec_sys_exit(void)
{
    debugfs_remove_recursive(acpi_ec_debugfs_dir);
}

module_init(acpi_ec_sys_init);
module_exit(acpi_ec_sys_exit);