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_hw(write_support, bool, other, 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(addr: *off, val: &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(addr: *off, val: 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(name: "ec" , NULL); |
118 | |
119 | sprintf(buf: name, fmt: "ec%u" , ec_device_count); |
120 | dev_dir = debugfs_create_dir(name, parent: acpi_ec_debugfs_dir); |
121 | |
122 | debugfs_create_x32(name: "gpe" , mode: 0444, parent: dev_dir, value: &first_ec->gpe); |
123 | debugfs_create_bool(name: "use_global_lock" , mode: 0444, parent: dev_dir, |
124 | value: &first_ec->global_lock); |
125 | |
126 | if (write_support) |
127 | mode = 0600; |
128 | debugfs_create_file(name: "io" , mode, parent: dev_dir, data: ec, fops: &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(ec: first_ec, ec_device_count: 0); |
135 | return 0; |
136 | } |
137 | |
138 | static void __exit acpi_ec_sys_exit(void) |
139 | { |
140 | debugfs_remove_recursive(dentry: acpi_ec_debugfs_dir); |
141 | } |
142 | |
143 | module_init(acpi_ec_sys_init); |
144 | module_exit(acpi_ec_sys_exit); |
145 | |