1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  Airplane mode button for AMD, HP & Xiaomi laptops
4  *
5  *  Copyright (C) 2014-2017 Alex Hung <alex.hung@canonical.com>
6  *  Copyright (C) 2021 Advanced Micro Devices
7  */
8 
9 #include <linux/kernel.h>
10 #include <linux/module.h>
11 #include <linux/init.h>
12 #include <linux/input.h>
13 #include <linux/platform_device.h>
14 #include <linux/acpi.h>
15 #include <acpi/acpi_bus.h>
16 
17 MODULE_LICENSE("GPL");
18 MODULE_AUTHOR("Alex Hung");
19 MODULE_ALIAS("acpi*:HPQ6001:*");
20 MODULE_ALIAS("acpi*:WSTADEF:*");
21 MODULE_ALIAS("acpi*:AMDI0051:*");
22 
23 struct wl_button {
24 	struct input_dev *input_dev;
25 	char phys[32];
26 };
27 
28 static const struct acpi_device_id wl_ids[] = {
29 	{"HPQ6001", 0},
30 	{"WSTADEF", 0},
31 	{"AMDI0051", 0},
32 	{"", 0},
33 };
34 
35 static int wireless_input_setup(struct acpi_device *device)
36 {
37 	struct wl_button *button = acpi_driver_data(device);
38 	int err;
39 
40 	button->input_dev = input_allocate_device();
41 	if (!button->input_dev)
42 		return -ENOMEM;
43 
44 	snprintf(button->phys, sizeof(button->phys), "%s/input0", acpi_device_hid(device));
45 
46 	button->input_dev->name = "Wireless hotkeys";
47 	button->input_dev->phys = button->phys;
48 	button->input_dev->id.bustype = BUS_HOST;
49 	button->input_dev->evbit[0] = BIT(EV_KEY);
50 	set_bit(KEY_RFKILL, button->input_dev->keybit);
51 
52 	err = input_register_device(button->input_dev);
53 	if (err)
54 		goto err_free_dev;
55 
56 	return 0;
57 
58 err_free_dev:
59 	input_free_device(button->input_dev);
60 	return err;
61 }
62 
63 static void wireless_input_destroy(struct acpi_device *device)
64 {
65 	struct wl_button *button = acpi_driver_data(device);
66 
67 	input_unregister_device(button->input_dev);
68 	kfree(button);
69 }
70 
71 static void wl_notify(struct acpi_device *acpi_dev, u32 event)
72 {
73 	struct wl_button *button = acpi_driver_data(acpi_dev);
74 
75 	if (event != 0x80) {
76 		pr_info("Received unknown event (0x%x)\n", event);
77 		return;
78 	}
79 
80 	input_report_key(button->input_dev, KEY_RFKILL, 1);
81 	input_sync(button->input_dev);
82 	input_report_key(button->input_dev, KEY_RFKILL, 0);
83 	input_sync(button->input_dev);
84 }
85 
86 static int wl_add(struct acpi_device *device)
87 {
88 	struct wl_button *button;
89 	int err;
90 
91 	button = kzalloc(sizeof(struct wl_button), GFP_KERNEL);
92 	if (!button)
93 		return -ENOMEM;
94 
95 	device->driver_data = button;
96 
97 	err = wireless_input_setup(device);
98 	if (err) {
99 		pr_err("Failed to setup wireless hotkeys\n");
100 		kfree(button);
101 	}
102 
103 	return err;
104 }
105 
106 static void wl_remove(struct acpi_device *device)
107 {
108 	wireless_input_destroy(device);
109 }
110 
111 static struct acpi_driver wl_driver = {
112 	.name	= "wireless-hotkey",
113 	.owner	= THIS_MODULE,
114 	.ids	= wl_ids,
115 	.ops	= {
116 		.add	= wl_add,
117 		.remove	= wl_remove,
118 		.notify	= wl_notify,
119 	},
120 };
121 
122 module_acpi_driver(wl_driver);
123