1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * PEAQ 2-in-1 WMI hotkey driver
  4 * Copyright (C) 2017 Hans de Goede <hdegoede@redhat.com>
  5 */
  6
  7#include <linux/acpi.h>
  8#include <linux/dmi.h>
  9#include <linux/input-polldev.h>
 10#include <linux/kernel.h>
 11#include <linux/module.h>
 12
 13#define PEAQ_DOLBY_BUTTON_GUID		"ABBC0F6F-8EA1-11D1-00A0-C90629100000"
 14#define PEAQ_DOLBY_BUTTON_METHOD_ID	5
 15#define PEAQ_POLL_INTERVAL_MS		250
 16#define PEAQ_POLL_IGNORE_MS		500
 17#define PEAQ_POLL_MAX_MS		1000
 18
 19MODULE_ALIAS("wmi:"PEAQ_DOLBY_BUTTON_GUID);
 20
 21static unsigned int peaq_ignore_events_counter;
 22static struct input_polled_dev *peaq_poll_dev;
 23
 24/*
 25 * The Dolby button (yes really a Dolby button) causes an ACPI variable to get
 26 * set on both press and release. The WMI method checks and clears that flag.
 27 * So for a press + release we will get back One from the WMI method either once
 28 * (if polling after the release) or twice (polling between press and release).
 29 * We ignore events for 0.5s after the first event to avoid reporting 2 presses.
 30 */
 31static void peaq_wmi_poll(struct input_polled_dev *dev)
 32{
 33	union acpi_object obj;
 34	acpi_status status;
 35	u32 dummy = 0;
 36
 37	struct acpi_buffer input = { sizeof(dummy), &dummy };
 38	struct acpi_buffer output = { sizeof(obj), &obj };
 39
 40	status = wmi_evaluate_method(PEAQ_DOLBY_BUTTON_GUID, 0,
 41				     PEAQ_DOLBY_BUTTON_METHOD_ID,
 42				     &input, &output);
 43	if (ACPI_FAILURE(status))
 44		return;
 45
 46	if (obj.type != ACPI_TYPE_INTEGER) {
 47		dev_err(&peaq_poll_dev->input->dev,
 48			"Error WMBC did not return an integer\n");
 49		return;
 50	}
 51
 52	if (peaq_ignore_events_counter && peaq_ignore_events_counter--)
 53		return;
 54
 55	if (obj.integer.value) {
 56		input_event(peaq_poll_dev->input, EV_KEY, KEY_SOUND, 1);
 57		input_sync(peaq_poll_dev->input);
 58		input_event(peaq_poll_dev->input, EV_KEY, KEY_SOUND, 0);
 59		input_sync(peaq_poll_dev->input);
 60		peaq_ignore_events_counter = max(1u,
 61			PEAQ_POLL_IGNORE_MS / peaq_poll_dev->poll_interval);
 62	}
 63}
 64
 65/* Some other devices (Shuttle XS35) use the same WMI GUID for other purposes */
 66static const struct dmi_system_id peaq_dmi_table[] __initconst = {
 67	{
 68		.matches = {
 69			DMI_MATCH(DMI_SYS_VENDOR, "PEAQ"),
 70			DMI_MATCH(DMI_PRODUCT_NAME, "PEAQ PMM C1010 MD99187"),
 71		},
 72	},
 73	{}
 74};
 75
 76static int __init peaq_wmi_init(void)
 77{
 78	/* WMI GUID is not unique, also check for a DMI match */
 79	if (!dmi_check_system(peaq_dmi_table))
 80		return -ENODEV;
 81
 82	if (!wmi_has_guid(PEAQ_DOLBY_BUTTON_GUID))
 83		return -ENODEV;
 84
 85	peaq_poll_dev = input_allocate_polled_device();
 86	if (!peaq_poll_dev)
 87		return -ENOMEM;
 88
 89	peaq_poll_dev->poll = peaq_wmi_poll;
 90	peaq_poll_dev->poll_interval = PEAQ_POLL_INTERVAL_MS;
 91	peaq_poll_dev->poll_interval_max = PEAQ_POLL_MAX_MS;
 92	peaq_poll_dev->input->name = "PEAQ WMI hotkeys";
 93	peaq_poll_dev->input->phys = "wmi/input0";
 94	peaq_poll_dev->input->id.bustype = BUS_HOST;
 95	input_set_capability(peaq_poll_dev->input, EV_KEY, KEY_SOUND);
 96
 97	return input_register_polled_device(peaq_poll_dev);
 98}
 99
100static void __exit peaq_wmi_exit(void)
101{
102	input_unregister_polled_device(peaq_poll_dev);
103}
104
105module_init(peaq_wmi_init);
106module_exit(peaq_wmi_exit);
107
108MODULE_DESCRIPTION("PEAQ 2-in-1 WMI hotkey driver");
109MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
110MODULE_LICENSE("GPL");