linux/drivers/acpi/ec_sys.c
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   1/*
   2 * ec_sys.c
   3 *
   4 * Copyright (C) 2010 SUSE Products GmbH/Novell
   5 * Author:
   6 *      Thomas Renninger <trenn@suse.de>
   7 *
   8 * This work is licensed under the terms of the GNU GPL, version 2.
   9 */
  10
  11#include <linux/kernel.h>
  12#include <linux/acpi.h>
  13#include <linux/debugfs.h>
  14#include <linux/module.h>
  15#include "internal.h"
  16
  17MODULE_AUTHOR("Thomas Renninger <trenn@suse.de>");
  18MODULE_DESCRIPTION("ACPI EC sysfs access driver");
  19MODULE_LICENSE("GPL");
  20
  21static bool write_support;
  22module_param(write_support, bool, 0644);
  23MODULE_PARM_DESC(write_support, "Dangerous, reboot and removal of battery may "
  24                 "be needed.");
  25
  26#define EC_SPACE_SIZE 256
  27
  28static struct dentry *acpi_ec_debugfs_dir;
  29
  30static ssize_t acpi_ec_read_io(struct file *f, char __user *buf,
  31                               size_t count, loff_t *off)
  32{
  33        /* Use this if support reading/writing multiple ECs exists in ec.c:
  34         * struct acpi_ec *ec = ((struct seq_file *)f->private_data)->private;
  35         */
  36        unsigned int size = EC_SPACE_SIZE;
  37        u8 *data = (u8 *) buf;
  38        loff_t init_off = *off;
  39        int err = 0;
  40
  41        if (*off >= size)
  42                return 0;
  43        if (*off + count >= size) {
  44                size -= *off;
  45                count = size;
  46        } else
  47                size = count;
  48
  49        while (size) {
  50                err = ec_read(*off, &data[*off - init_off]);
  51                if (err)
  52                        return err;
  53                *off += 1;
  54                size--;
  55        }
  56        return count;
  57}
  58
  59static ssize_t acpi_ec_write_io(struct file *f, const char __user *buf,
  60                                size_t count, loff_t *off)
  61{
  62        /* Use this if support reading/writing multiple ECs exists in ec.c:
  63         * struct acpi_ec *ec = ((struct seq_file *)f->private_data)->private;
  64         */
  65
  66        unsigned int size = count;
  67        loff_t init_off = *off;
  68        u8 *data = (u8 *) buf;
  69        int err = 0;
  70
  71        if (*off >= EC_SPACE_SIZE)
  72                return 0;
  73        if (*off + count >= EC_SPACE_SIZE) {
  74                size = EC_SPACE_SIZE - *off;
  75                count = size;
  76        }
  77
  78        while (size) {
  79                u8 byte_write = data[*off - init_off];
  80                err = ec_write(*off, byte_write);
  81                if (err)
  82                        return err;
  83
  84                *off += 1;
  85                size--;
  86        }
  87        return count;
  88}
  89
  90static const struct file_operations acpi_ec_io_ops = {
  91        .owner = THIS_MODULE,
  92        .open  = simple_open,
  93        .read  = acpi_ec_read_io,
  94        .write = acpi_ec_write_io,
  95        .llseek = default_llseek,
  96};
  97
  98int acpi_ec_add_debugfs(struct acpi_ec *ec, unsigned int ec_device_count)
  99{
 100        struct dentry *dev_dir;
 101        char name[64];
 102        umode_t mode = 0400;
 103
 104        if (ec_device_count == 0) {
 105                acpi_ec_debugfs_dir = debugfs_create_dir("ec", NULL);
 106                if (!acpi_ec_debugfs_dir)
 107                        return -ENOMEM;
 108        }
 109
 110        sprintf(name, "ec%u", ec_device_count);
 111        dev_dir = debugfs_create_dir(name, acpi_ec_debugfs_dir);
 112        if (!dev_dir) {
 113                if (ec_device_count != 0)
 114                        goto error;
 115                return -ENOMEM;
 116        }
 117
 118        if (!debugfs_create_x32("gpe", 0444, dev_dir, (u32 *)&first_ec->gpe))
 119                goto error;
 120        if (!debugfs_create_bool("use_global_lock", 0444, dev_dir,
 121                                 (u32 *)&first_ec->global_lock))
 122                goto error;
 123
 124        if (write_support)
 125                mode = 0600;
 126        if (!debugfs_create_file("io", mode, dev_dir, ec, &acpi_ec_io_ops))
 127                goto error;
 128
 129        return 0;
 130
 131error:
 132        debugfs_remove_recursive(acpi_ec_debugfs_dir);
 133        return -ENOMEM;
 134}
 135
 136static int __init acpi_ec_sys_init(void)
 137{
 138        int err = 0;
 139        if (first_ec)
 140                err = acpi_ec_add_debugfs(first_ec, 0);
 141        else
 142                err = -ENODEV;
 143        return err;
 144}
 145
 146static void __exit acpi_ec_sys_exit(void)
 147{
 148        debugfs_remove_recursive(acpi_ec_debugfs_dir);
 149}
 150
 151module_init(acpi_ec_sys_init);
 152module_exit(acpi_ec_sys_exit);
 153
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