1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  adv_swbutton.c - Software Button Interface Driver.
4  *
5  *  (C) Copyright 2020 Advantech Corporation, Inc
6  *
7  */
8 #include <linux/kernel.h>
9 #include <linux/module.h>
10 #include <linux/input.h>
11 #include <linux/acpi.h>
12 #include <linux/platform_device.h>
13 
14 #define ACPI_BUTTON_HID_SWBTN               "AHC0310"
15 
16 #define ACPI_BUTTON_NOTIFY_SWBTN_RELEASE    0x86
17 #define ACPI_BUTTON_NOTIFY_SWBTN_PRESSED    0x85
18 
19 struct adv_swbutton {
20 	struct input_dev *input;
21 	char phys[32];
22 };
23 
24 /*-------------------------------------------------------------------------
25  *                               Driver Interface
26  *--------------------------------------------------------------------------
27  */
28 static void adv_swbutton_notify(acpi_handle handle, u32 event, void *context)
29 {
30 	struct platform_device *device = context;
31 	struct adv_swbutton *button = dev_get_drvdata(&device->dev);
32 
33 	switch (event) {
34 	case ACPI_BUTTON_NOTIFY_SWBTN_RELEASE:
35 		input_report_key(button->input, KEY_PROG1, 0);
36 		input_sync(button->input);
37 		break;
38 	case ACPI_BUTTON_NOTIFY_SWBTN_PRESSED:
39 		input_report_key(button->input, KEY_PROG1, 1);
40 		input_sync(button->input);
41 		break;
42 	default:
43 		dev_dbg(&device->dev, "Unsupported event [0x%x]\n", event);
44 	}
45 }
46 
47 static int adv_swbutton_probe(struct platform_device *device)
48 {
49 	struct adv_swbutton *button;
50 	struct input_dev *input;
51 	acpi_handle handle = ACPI_HANDLE(&device->dev);
52 	acpi_status status;
53 	int error;
54 
55 	button = devm_kzalloc(&device->dev, sizeof(*button), GFP_KERNEL);
56 	if (!button)
57 		return -ENOMEM;
58 
59 	dev_set_drvdata(&device->dev, button);
60 
61 	input = devm_input_allocate_device(&device->dev);
62 	if (!input)
63 		return -ENOMEM;
64 
65 	button->input = input;
66 	snprintf(button->phys, sizeof(button->phys), "%s/button/input0", ACPI_BUTTON_HID_SWBTN);
67 
68 	input->name = "Advantech Software Button";
69 	input->phys = button->phys;
70 	input->id.bustype = BUS_HOST;
71 	input->dev.parent = &device->dev;
72 	set_bit(EV_REP, input->evbit);
73 	input_set_capability(input, EV_KEY, KEY_PROG1);
74 
75 	error = input_register_device(input);
76 	if (error)
77 		return error;
78 
79 	device_init_wakeup(&device->dev, true);
80 
81 	status = acpi_install_notify_handler(handle,
82 					     ACPI_DEVICE_NOTIFY,
83 					     adv_swbutton_notify,
84 					     device);
85 	if (ACPI_FAILURE(status)) {
86 		dev_err(&device->dev, "Error installing notify handler\n");
87 		return -EIO;
88 	}
89 
90 	return 0;
91 }
92 
93 static void adv_swbutton_remove(struct platform_device *device)
94 {
95 	acpi_handle handle = ACPI_HANDLE(&device->dev);
96 
97 	acpi_remove_notify_handler(handle, ACPI_DEVICE_NOTIFY,
98 				   adv_swbutton_notify);
99 }
100 
101 static const struct acpi_device_id button_device_ids[] = {
102 	{ACPI_BUTTON_HID_SWBTN, 0},
103 	{"", 0},
104 };
105 MODULE_DEVICE_TABLE(acpi, button_device_ids);
106 
107 static struct platform_driver adv_swbutton_driver = {
108 	.driver = {
109 		.name = "adv_swbutton",
110 		.acpi_match_table = button_device_ids,
111 	},
112 	.probe = adv_swbutton_probe,
113 	.remove_new = adv_swbutton_remove,
114 };
115 module_platform_driver(adv_swbutton_driver);
116 
117 MODULE_AUTHOR("Andrea Ho");
118 MODULE_DESCRIPTION("Advantech ACPI SW Button Driver");
119 MODULE_LICENSE("GPL v2");
120