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