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 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
  59 static 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
  90 static 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
  98 int 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
 131 error:
 132         debugfs_remove_recursive(acpi_ec_debugfs_dir);
 133         return -ENOMEM;
 134 }
 135
 136 static 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
 146 static void __exit acpi_ec_sys_exit(void)
 147 {
 148         debugfs_remove_recursive(acpi_ec_debugfs_dir);
 149 }
 150
 151 module_init(acpi_ec_sys_init);
 152 module_exit(acpi_ec_sys_exit);