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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 <[email protected]>
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
17MODULE_AUTHOR("Thomas Renninger <[email protected]>");
18MODULE_DESCRIPTION("ACPI EC sysfs access driver");
19MODULE_LICENSE("GPL");
20
21static bool write_support;
22module_param_hw(write_support, bool, other, 0644);
23MODULE_PARM_DESC(write_support, "Dangerous, reboot and removal of battery may "
24 "be needed.");
25
26#define EC_SPACE_SIZE 256
27
28static struct dentry *acpi_ec_debugfs_dir;
29
30static 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
64static 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
102static 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
110static 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
131static 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
138static void __exit acpi_ec_sys_exit(void)
139{
140 debugfs_remove_recursive(acpi_ec_debugfs_dir);
141}
142
143module_init(acpi_ec_sys_init);
144module_exit(acpi_ec_sys_exit);