1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 *  WMI hotkeys support for Dell All-In-One series
4 */
5
6#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
7
8#include <linux/kernel.h>
9#include <linux/module.h>
10#include <linux/init.h>
11#include <linux/types.h>
12#include <linux/input.h>
13#include <linux/input/sparse-keymap.h>
14#include <linux/acpi.h>
15#include <linux/string.h>
16
17MODULE_DESCRIPTION("WMI hotkeys driver for Dell All-In-One series");
18MODULE_LICENSE("GPL");
19
20#define EVENT_GUID1 "284A0E6B-380E-472A-921F-E52786257FB4"
21#define EVENT_GUID2 "02314822-307C-4F66-BF0E-48AEAEB26CC8"
22
23struct dell_wmi_event {
24	u16	length;
25	/* 0x000: A hot key pressed or an event occurred
26	 * 0x00F: A sequence of hot keys are pressed */
27	u16	type;
28	u16	event[];
29};
30
31static const char *dell_wmi_aio_guids[] = {
32	EVENT_GUID1,
33	EVENT_GUID2,
34	NULL
35};
36
37MODULE_ALIAS("wmi:"EVENT_GUID1);
38MODULE_ALIAS("wmi:"EVENT_GUID2);
39
40static const struct key_entry dell_wmi_aio_keymap[] = {
41	{ KE_KEY, 0xc0, { KEY_VOLUMEUP } },
42	{ KE_KEY, 0xc1, { KEY_VOLUMEDOWN } },
43	{ KE_KEY, 0xe030, { KEY_VOLUMEUP } },
44	{ KE_KEY, 0xe02e, { KEY_VOLUMEDOWN } },
45	{ KE_KEY, 0xe020, { KEY_MUTE } },
46	{ KE_KEY, 0xe027, { KEY_DISPLAYTOGGLE } },
47	{ KE_KEY, 0xe006, { KEY_BRIGHTNESSUP } },
48	{ KE_KEY, 0xe005, { KEY_BRIGHTNESSDOWN } },
49	{ KE_KEY, 0xe00b, { KEY_SWITCHVIDEOMODE } },
50	{ KE_END, 0 }
51};
52
53static struct input_dev *dell_wmi_aio_input_dev;
54
55/*
56 * The new WMI event data format will follow the dell_wmi_event structure
57 * So, we will check if the buffer matches the format
58 */
59static bool dell_wmi_aio_event_check(u8 *buffer, int length)
60{
61	struct dell_wmi_event *event = (struct dell_wmi_event *)buffer;
62
63	if (event == NULL || length < 6)
64		return false;
65
66	if ((event->type == 0 || event->type == 0xf) &&
67			event->length >= 2)
68		return true;
69
70	return false;
71}
72
73static void dell_wmi_aio_notify(u32 value, void *context)
74{
75	struct acpi_buffer response = { ACPI_ALLOCATE_BUFFER, NULL };
76	union acpi_object *obj;
77	struct dell_wmi_event *event;
78	acpi_status status;
79
80	status = wmi_get_event_data(value, &response);
81	if (status != AE_OK) {
82		pr_info("bad event status 0x%x\n", status);
83		return;
84	}
85
86	obj = (union acpi_object *)response.pointer;
87	if (obj) {
88		unsigned int scancode = 0;
89
90		switch (obj->type) {
91		case ACPI_TYPE_INTEGER:
92			/* Most All-In-One correctly return integer scancode */
93			scancode = obj->integer.value;
94			sparse_keymap_report_event(dell_wmi_aio_input_dev,
95				scancode, 1, true);
96			break;
97		case ACPI_TYPE_BUFFER:
98			if (dell_wmi_aio_event_check(obj->buffer.pointer,
99						obj->buffer.length)) {
100				event = (struct dell_wmi_event *)
101					obj->buffer.pointer;
102				scancode = event->event[0];
103			} else {
104				/* Broken machines return the scancode in a
105				   buffer */
106				if (obj->buffer.pointer &&
107						obj->buffer.length > 0)
108					scancode = obj->buffer.pointer[0];
109			}
110			if (scancode)
111				sparse_keymap_report_event(
112					dell_wmi_aio_input_dev,
113					scancode, 1, true);
114			break;
115		}
116	}
117	kfree(obj);
118}
119
120static int __init dell_wmi_aio_input_setup(void)
121{
122	int err;
123
124	dell_wmi_aio_input_dev = input_allocate_device();
125
126	if (!dell_wmi_aio_input_dev)
127		return -ENOMEM;
128
129	dell_wmi_aio_input_dev->name = "Dell AIO WMI hotkeys";
130	dell_wmi_aio_input_dev->phys = "wmi/input0";
131	dell_wmi_aio_input_dev->id.bustype = BUS_HOST;
132
133	err = sparse_keymap_setup(dell_wmi_aio_input_dev,
134			dell_wmi_aio_keymap, NULL);
135	if (err) {
136		pr_err("Unable to setup input device keymap\n");
137		goto err_free_dev;
138	}
139	err = input_register_device(dell_wmi_aio_input_dev);
140	if (err) {
141		pr_info("Unable to register input device\n");
142		goto err_free_dev;
143	}
144	return 0;
145
146err_free_dev:
147	input_free_device(dell_wmi_aio_input_dev);
148	return err;
149}
150
151static const char *dell_wmi_aio_find(void)
152{
153	int i;
154
155	for (i = 0; dell_wmi_aio_guids[i] != NULL; i++)
156		if (wmi_has_guid(dell_wmi_aio_guids[i]))
157			return dell_wmi_aio_guids[i];
158
159	return NULL;
160}
161
162static int __init dell_wmi_aio_init(void)
163{
164	int err;
165	const char *guid;
166
167	guid = dell_wmi_aio_find();
168	if (!guid) {
169		pr_warn("No known WMI GUID found\n");
170		return -ENXIO;
171	}
172
173	err = dell_wmi_aio_input_setup();
174	if (err)
175		return err;
176
177	err = wmi_install_notify_handler(guid, dell_wmi_aio_notify, NULL);
178	if (err) {
179		pr_err("Unable to register notify handler - %d\n", err);
180		input_unregister_device(dell_wmi_aio_input_dev);
181		return err;
182	}
183
184	return 0;
185}
186
187static void __exit dell_wmi_aio_exit(void)
188{
189	const char *guid;
190
191	guid = dell_wmi_aio_find();
192	wmi_remove_notify_handler(guid);
193	input_unregister_device(dell_wmi_aio_input_dev);
194}
195
196module_init(dell_wmi_aio_init);
197module_exit(dell_wmi_aio_exit);
198