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