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 "internal.h"
  15
  16 MODULE_AUTHOR("Thomas Renninger <trenn@suse.de>");
  17 MODULE_DESCRIPTION("ACPI EC sysfs access driver");
  18 MODULE_LICENSE("GPL");
  19
  20 static bool write_support;
  21 module_param(write_support, bool, 0644);
  22 MODULE_PARM_DESC(write_support, "Dangerous, reboot and removal of battery may "
  23                  "be needed.");
  24
  25 #define EC_SPACE_SIZE 256
  26
  27 struct sysdev_class acpi_ec_sysdev_class = {
  28         .name = "ec",
  29 };
  30
  31 static struct dentry *acpi_ec_debugfs_dir;
  32
  33 static int acpi_ec_open_io(struct inode *i, struct file *f)
  34 {
  35         f->private_data = i->i_private;
  36         return 0;
  37 }
  38
  39 static ssize_t acpi_ec_read_io(struct file *f, char __user *buf,
  40                                size_t count, loff_t *off)
  41 {
  42         /* Use this if support reading/writing multiple ECs exists in ec.c:
  43          * struct acpi_ec *ec = ((struct seq_file *)f->private_data)->private;
  44          */
  45         unsigned int size = EC_SPACE_SIZE;
  46         u8 *data = (u8 *) buf;
  47         loff_t init_off = *off;
  48         int err = 0;
  49
  50         if (*off >= size)
  51                 return 0;
  52         if (*off + count >= size) {
  53                 size -= *off;
  54                 count = size;
  55         } else
  56                 size = count;
  57
  58         while (size) {
  59                 err = ec_read(*off, &data[*off - init_off]);
  60                 if (err)
  61                         return err;
  62                 *off += 1;
  63                 size--;
  64         }
  65         return count;
  66 }
  67
  68 static ssize_t acpi_ec_write_io(struct file *f, const char __user *buf,
  69                                 size_t count, loff_t *off)
  70 {
  71         /* Use this if support reading/writing multiple ECs exists in ec.c:
  72          * struct acpi_ec *ec = ((struct seq_file *)f->private_data)->private;
  73          */
  74
  75         unsigned int size = count;
  76         loff_t init_off = *off;
  77         u8 *data = (u8 *) buf;
  78         int err = 0;
  79
  80         if (*off >= EC_SPACE_SIZE)
  81                 return 0;
  82         if (*off + count >= EC_SPACE_SIZE) {
  83                 size = EC_SPACE_SIZE - *off;
  84                 count = size;
  85         }
  86
  87         while (size) {
  88                 u8 byte_write = data[*off - init_off];
  89                 err = ec_write(*off, byte_write);
  90                 if (err)
  91                         return err;
  92
  93                 *off += 1;
  94                 size--;
  95         }
  96         return count;
  97 }
  98
  99 static struct file_operations acpi_ec_io_ops = {
 100         .owner = THIS_MODULE,
 101         .open  = acpi_ec_open_io,
 102         .read  = acpi_ec_read_io,
 103         .write = acpi_ec_write_io,
 104 };
 105
 106 int acpi_ec_add_debugfs(struct acpi_ec *ec, unsigned int ec_device_count)
 107 {
 108         struct dentry *dev_dir;
 109         char name[64];
 110         mode_t mode = 0400;
 111
 112         if (ec_device_count == 0) {
 113                 acpi_ec_debugfs_dir = debugfs_create_dir("ec", NULL);
 114                 if (!acpi_ec_debugfs_dir)
 115                         return -ENOMEM;
 116         }
 117
 118         sprintf(name, "ec%u", ec_device_count);
 119         dev_dir = debugfs_create_dir(name, acpi_ec_debugfs_dir);
 120         if (!dev_dir) {
 121                 if (ec_device_count != 0)
 122                         goto error;
 123                 return -ENOMEM;
 124         }
 125
 126         if (!debugfs_create_x32("gpe", 0444, dev_dir, (u32 *)&first_ec->gpe))
 127                 goto error;
 128         if (!debugfs_create_bool("use_global_lock", 0444, dev_dir,
 129                                  (u32 *)&first_ec->global_lock))
 130                 goto error;
 131
 132         if (write_support)
 133                 mode = 0600;
 134         if (!debugfs_create_file("io", mode, dev_dir, ec, &acpi_ec_io_ops))
 135                 goto error;
 136
 137         return 0;
 138
 139 error:
 140         debugfs_remove_recursive(acpi_ec_debugfs_dir);
 141         return -ENOMEM;
 142 }
 143
 144 static int __init acpi_ec_sys_init(void)
 145 {
 146         int err = 0;
 147         if (first_ec)
 148                 err = acpi_ec_add_debugfs(first_ec, 0);
 149         else
 150                 err = -ENODEV;
 151         return err;
 152 }
 153
 154 static void __exit acpi_ec_sys_exit(void)
 155 {
 156         debugfs_remove_recursive(acpi_ec_debugfs_dir);
 157 }
 158
 159 module_init(acpi_ec_sys_init);
 160 module_exit(acpi_ec_sys_exit);