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 (*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;
85		if (get_user(byte_write, buf + *off - init_off)) {
86			if (*off - init_off)
87				return *off - init_off; /* partial write */
88			return -EFAULT;
89		}
90		err = ec_write(*off, byte_write);
91		if (err)
92			return err;
93
94		*off += 1;
95		size--;
96	}
97	return count;
98}
99
100static const struct file_operations acpi_ec_io_ops = {
101	.owner = THIS_MODULE,
102	.open  = simple_open,
103	.read  = acpi_ec_read_io,
104	.write = acpi_ec_write_io,
105	.llseek = default_llseek,
106};
107
108static int acpi_ec_add_debugfs(struct acpi_ec *ec, unsigned int ec_device_count)
109{
110	struct dentry *dev_dir;
111	char name[64];
112	umode_t mode = 0400;
113
114	if (ec_device_count == 0) {
115		acpi_ec_debugfs_dir = debugfs_create_dir("ec", NULL);
116		if (!acpi_ec_debugfs_dir)
117			return -ENOMEM;
118	}
119
120	sprintf(name, "ec%u", ec_device_count);
121	dev_dir = debugfs_create_dir(name, acpi_ec_debugfs_dir);
122	if (!dev_dir) {
123		if (ec_device_count != 0)
124			goto error;
125		return -ENOMEM;
126	}
127
128	if (!debugfs_create_x32("gpe", 0444, dev_dir, (u32 *)&first_ec->gpe))
129		goto error;
130	if (!debugfs_create_bool("use_global_lock", 0444, dev_dir,
131				 (u32 *)&first_ec->global_lock))
132		goto error;
133
134	if (write_support)
135		mode = 0600;
136	if (!debugfs_create_file("io", mode, dev_dir, ec, &acpi_ec_io_ops))
137		goto error;
138
139	return 0;
140
141error:
142	debugfs_remove_recursive(acpi_ec_debugfs_dir);
143	return -ENOMEM;
144}
145
146static int __init acpi_ec_sys_init(void)
147{
148	int err = 0;
149	if (first_ec)
150		err = acpi_ec_add_debugfs(first_ec, 0);
151	else
152		err = -ENODEV;
153	return err;
154}
155
156static void __exit acpi_ec_sys_exit(void)
157{
158	debugfs_remove_recursive(acpi_ec_debugfs_dir);
159}
160
161module_init(acpi_ec_sys_init);
162module_exit(acpi_ec_sys_exit);
163