tools headers UAPI: Sync files changed by the quotactl_path unwiring
[linux-2.6-microblaze.git] / drivers / acpi / ec_sys.c
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * ec_sys.c
4  *
5  * Copyright (C) 2010 SUSE Products GmbH/Novell
6  * Author:
7  *      Thomas Renninger <trenn@suse.de>
8  */
9
10 #include <linux/kernel.h>
11 #include <linux/acpi.h>
12 #include <linux/debugfs.h>
13 #include <linux/module.h>
14 #include <linux/uaccess.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         loff_t init_off = *off;
38         int err = 0;
39
40         if (*off >= size)
41                 return 0;
42         if (*off + count >= size) {
43                 size -= *off;
44                 count = size;
45         } else
46                 size = count;
47
48         while (size) {
49                 u8 byte_read;
50                 err = ec_read(*off, &byte_read);
51                 if (err)
52                         return err;
53                 if (put_user(byte_read, buf + *off - init_off)) {
54                         if (*off - init_off)
55                                 return *off - init_off; /* partial read */
56                         return -EFAULT;
57                 }
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         int err = 0;
74
75         if (!write_support)
76                 return -EINVAL;
77
78         if (*off >= EC_SPACE_SIZE)
79                 return 0;
80         if (*off + count >= EC_SPACE_SIZE) {
81                 size = EC_SPACE_SIZE - *off;
82                 count = size;
83         }
84
85         while (size) {
86                 u8 byte_write;
87                 if (get_user(byte_write, buf + *off - init_off)) {
88                         if (*off - init_off)
89                                 return *off - init_off; /* partial write */
90                         return -EFAULT;
91                 }
92                 err = ec_write(*off, byte_write);
93                 if (err)
94                         return err;
95
96                 *off += 1;
97                 size--;
98         }
99         return count;
100 }
101
102 static const struct file_operations acpi_ec_io_ops = {
103         .owner = THIS_MODULE,
104         .open  = simple_open,
105         .read  = acpi_ec_read_io,
106         .write = acpi_ec_write_io,
107         .llseek = default_llseek,
108 };
109
110 static void acpi_ec_add_debugfs(struct acpi_ec *ec, unsigned int ec_device_count)
111 {
112         struct dentry *dev_dir;
113         char name[64];
114         umode_t mode = 0400;
115
116         if (ec_device_count == 0)
117                 acpi_ec_debugfs_dir = debugfs_create_dir("ec", NULL);
118
119         sprintf(name, "ec%u", ec_device_count);
120         dev_dir = debugfs_create_dir(name, acpi_ec_debugfs_dir);
121
122         debugfs_create_x32("gpe", 0444, dev_dir, &first_ec->gpe);
123         debugfs_create_bool("use_global_lock", 0444, dev_dir,
124                             &first_ec->global_lock);
125
126         if (write_support)
127                 mode = 0600;
128         debugfs_create_file("io", mode, dev_dir, ec, &acpi_ec_io_ops);
129 }
130
131 static int __init acpi_ec_sys_init(void)
132 {
133         if (first_ec)
134                 acpi_ec_add_debugfs(first_ec, 0);
135         return 0;
136 }
137
138 static void __exit acpi_ec_sys_exit(void)
139 {
140         debugfs_remove_recursive(acpi_ec_debugfs_dir);
141 }
142
143 module_init(acpi_ec_sys_init);
144 module_exit(acpi_ec_sys_exit);