drivers/acpi/ec_sys.c

   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
  17 MODULE_AUTHOR("Thomas Renninger <trenn@suse.de>");
  18 MODULE_DESCRIPTION("ACPI EC sysfs access driver");
  19 MODULE_LICENSE("GPL");
  20
  21 static bool write_support;
  22 module_param(write_support, bool, 0644);
  23 MODULE_PARM_DESC(write_support, "Dangerous, reboot and removal of battery may "
  24                  "be needed.");
  25
  26 #define EC_SPACE_SIZE 256
  27
  28 static struct dentry *acpi_ec_debugfs_dir;
  29
  30 static int acpi_ec_open_io(struct inode *i, struct file *f)
  31 {
  32         f->private_data = i->i_private;
  33         return 0;
  34 }
  35
  36 static ssize_t acpi_ec_read_io(struct file *f, char __user *buf,
  37                                size_t count, loff_t *off)
  38 {
  39         /* Use this if support reading/writing multiple ECs exists in ec.c:
  40          * struct acpi_ec *ec = ((struct seq_file *)f->private_data)->private;
  41          */
  42         unsigned int size = EC_SPACE_SIZE;
  43         u8 *data = (u8 *) buf;
  44         loff_t init_off = *off;
  45         int err = 0;
  46
  47         if (*off >= size)
  48                 return 0;
  49         if (*off + count >= size) {
  50                 size -= *off;
  51                 count = size;
  52         } else
  53                 size = count;
  54
  55         while (size) {
  56                 err = ec_read(*off, &data[*off - init_off]);
  57                 if (err)
  58                         return err;
  59                 *off += 1;
  60                 size--;
  61         }
  62         return count;
  63 }
  64
  65 static ssize_t acpi_ec_write_io(struct file *f, const char __user *buf,
  66                                 size_t count, loff_t *off)
  67 {
  68         /* Use this if support reading/writing multiple ECs exists in ec.c:
  69          * struct acpi_ec *ec = ((struct seq_file *)f->private_data)->private;
  70          */
  71
  72         unsigned int size = count;
  73         loff_t init_off = *off;
  74         u8 *data = (u8 *) buf;
  75         int err = 0;
  76
  77         if (*off >= EC_SPACE_SIZE)
  78                 return 0;
  79         if (*off + count >= EC_SPACE_SIZE) {
  80                 size = EC_SPACE_SIZE - *off;
  81                 count = size;
  82         }
  83
  84         while (size) {
  85                 u8 byte_write = data[*off - init_off];
  86                 err = ec_write(*off, byte_write);
  87                 if (err)
  88                         return err;
  89
  90                 *off += 1;
  91                 size--;
  92         }
  93         return count;
  94 }
  95
  96 static const struct file_operations acpi_ec_io_ops = {
  97         .owner = THIS_MODULE,
  98         .open  = acpi_ec_open_io,
  99         .read  = acpi_ec_read_io,
 100         .write = acpi_ec_write_io,
 101         .llseek = default_llseek,
 102 };
 103
 104 int acpi_ec_add_debugfs(struct acpi_ec *ec, unsigned int ec_device_count)
 105 {
 106         struct dentry *dev_dir;
 107         char name[64];
 108         umode_t mode = 0400;
 109
 110         if (ec_device_count == 0) {
 111                 acpi_ec_debugfs_dir = debugfs_create_dir("ec", NULL);
 112                 if (!acpi_ec_debugfs_dir)
 113                         return -ENOMEM;
 114         }
 115
 116         sprintf(name, "ec%u", ec_device_count);
 117         dev_dir = debugfs_create_dir(name, acpi_ec_debugfs_dir);
 118         if (!dev_dir) {
 119                 if (ec_device_count != 0)
 120                         goto error;
 121                 return -ENOMEM;
 122         }
 123
 124         if (!debugfs_create_x32("gpe", 0444, dev_dir, (u32 *)&first_ec->gpe))
 125                 goto error;
 126         if (!debugfs_create_bool("use_global_lock", 0444, dev_dir,
 127                                  (u32 *)&first_ec->global_lock))
 128                 goto error;
 129
 130         if (write_support)
 131                 mode = 0600;
 132         if (!debugfs_create_file("io", mode, dev_dir, ec, &acpi_ec_io_ops))
 133                 goto error;
 134
 135         return 0;
 136
 137 error:
 138         debugfs_remove_recursive(acpi_ec_debugfs_dir);
 139         return -ENOMEM;
 140 }
 141
 142 static int __init acpi_ec_sys_init(void)
 143 {
 144         int err = 0;
 145         if (first_ec)
 146                 err = acpi_ec_add_debugfs(first_ec, 0);
 147         else
 148                 err = -ENODEV;
 149         return err;
 150 }
 151
 152 static void __exit acpi_ec_sys_exit(void)
 153 {
 154         debugfs_remove_recursive(acpi_ec_debugfs_dir);
 155 }
 156
 157 module_init(acpi_ec_sys_init);
 158 module_exit(acpi_ec_sys_exit);