dell-wmi-aio.c

  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(union acpi_object *obj, void *context)
 74{
 75	struct dell_wmi_event *event;
 76
 77	if (obj) {
 78		unsigned int scancode = 0;
 79
 80		switch (obj->type) {
 81		case ACPI_TYPE_INTEGER:
 82			/* Most All-In-One correctly return integer scancode */
 83			scancode = obj->integer.value;
 84			sparse_keymap_report_event(dell_wmi_aio_input_dev,
 85				scancode, 1, true);
 86			break;
 87		case ACPI_TYPE_BUFFER:
 88			if (dell_wmi_aio_event_check(obj->buffer.pointer,
 89						obj->buffer.length)) {
 90				event = (struct dell_wmi_event *)
 91					obj->buffer.pointer;
 92				scancode = event->event[0];
 93			} else {
 94				/* Broken machines return the scancode in a
 95				   buffer */
 96				if (obj->buffer.pointer &&
 97						obj->buffer.length > 0)
 98					scancode = obj->buffer.pointer[0];
 99			}
100			if (scancode)
101				sparse_keymap_report_event(
102					dell_wmi_aio_input_dev,
103					scancode, 1, true);
104			break;
105		}
106	}
107}
108
109static int __init dell_wmi_aio_input_setup(void)
110{
111	int err;
112
113	dell_wmi_aio_input_dev = input_allocate_device();
114
115	if (!dell_wmi_aio_input_dev)
116		return -ENOMEM;
117
118	dell_wmi_aio_input_dev->name = "Dell AIO WMI hotkeys";
119	dell_wmi_aio_input_dev->phys = "wmi/input0";
120	dell_wmi_aio_input_dev->id.bustype = BUS_HOST;
121
122	err = sparse_keymap_setup(dell_wmi_aio_input_dev,
123			dell_wmi_aio_keymap, NULL);
124	if (err) {
125		pr_err("Unable to setup input device keymap\n");
126		goto err_free_dev;
127	}
128	err = input_register_device(dell_wmi_aio_input_dev);
129	if (err) {
130		pr_info("Unable to register input device\n");
131		goto err_free_dev;
132	}
133	return 0;
134
135err_free_dev:
136	input_free_device(dell_wmi_aio_input_dev);
137	return err;
138}
139
140static const char *dell_wmi_aio_find(void)
141{
142	int i;
143
144	for (i = 0; dell_wmi_aio_guids[i] != NULL; i++)
145		if (wmi_has_guid(dell_wmi_aio_guids[i]))
146			return dell_wmi_aio_guids[i];
147
148	return NULL;
149}
150
151static int __init dell_wmi_aio_init(void)
152{
153	int err;
154	const char *guid;
155
156	guid = dell_wmi_aio_find();
157	if (!guid) {
158		pr_warn("No known WMI GUID found\n");
159		return -ENXIO;
160	}
161
162	err = dell_wmi_aio_input_setup();
163	if (err)
164		return err;
165
166	err = wmi_install_notify_handler(guid, dell_wmi_aio_notify, NULL);
167	if (err) {
168		pr_err("Unable to register notify handler - %d\n", err);
169		input_unregister_device(dell_wmi_aio_input_dev);
170		return err;
171	}
172
173	return 0;
174}
175
176static void __exit dell_wmi_aio_exit(void)
177{
178	const char *guid;
179
180	guid = dell_wmi_aio_find();
181	wmi_remove_notify_handler(guid);
182	input_unregister_device(dell_wmi_aio_input_dev);
183}
184
185module_init(dell_wmi_aio_init);
186module_exit(dell_wmi_aio_exit);