1/*
  2 * PEAQ 2-in-1 WMI hotkey driver
  3 * Copyright (C) 2017 Hans de Goede <hdegoede@redhat.com>
  4 *
  5 * This program is free software; you can redistribute it and/or modify
  6 * it under the terms of the GNU General Public License version 2 as
  7 * published by the Free Software Foundation.
  8 */
  9
 10#include <linux/acpi.h>
 11#include <linux/dmi.h>
 12#include <linux/input-polldev.h>
 13#include <linux/kernel.h>
 14#include <linux/module.h>
 15
 16#define PEAQ_DOLBY_BUTTON_GUID		"ABBC0F6F-8EA1-11D1-00A0-C90629100000"
 17#define PEAQ_DOLBY_BUTTON_METHOD_ID	5
 18#define PEAQ_POLL_INTERVAL_MS		250
 19#define PEAQ_POLL_IGNORE_MS		500
 20#define PEAQ_POLL_MAX_MS		1000
 21
 22MODULE_ALIAS("wmi:"PEAQ_DOLBY_BUTTON_GUID);
 23
 24static unsigned int peaq_ignore_events_counter;
 25static struct input_polled_dev *peaq_poll_dev;
 26
 27/*
 28 * The Dolby button (yes really a Dolby button) causes an ACPI variable to get
 29 * set on both press and release. The WMI method checks and clears that flag.
 30 * So for a press + release we will get back One from the WMI method either once
 31 * (if polling after the release) or twice (polling between press and release).
 32 * We ignore events for 0.5s after the first event to avoid reporting 2 presses.
 33 */
 34static void peaq_wmi_poll(struct input_polled_dev *dev)
 35{
 36	union acpi_object obj;
 37	acpi_status status;
 38	u32 dummy = 0;
 39
 40	struct acpi_buffer input = { sizeof(dummy), &dummy };
 41	struct acpi_buffer output = { sizeof(obj), &obj };
 42
 43	status = wmi_evaluate_method(PEAQ_DOLBY_BUTTON_GUID, 0,
 44				     PEAQ_DOLBY_BUTTON_METHOD_ID,
 45				     &input, &output);
 46	if (ACPI_FAILURE(status))
 47		return;
 48
 49	if (obj.type != ACPI_TYPE_INTEGER) {
 50		dev_err(&peaq_poll_dev->input->dev,
 51			"Error WMBC did not return an integer\n");
 52		return;
 53	}
 54
 55	if (peaq_ignore_events_counter && peaq_ignore_events_counter--)
 56		return;
 57
 58	if (obj.integer.value) {
 59		input_event(peaq_poll_dev->input, EV_KEY, KEY_SOUND, 1);
 60		input_sync(peaq_poll_dev->input);
 61		input_event(peaq_poll_dev->input, EV_KEY, KEY_SOUND, 0);
 62		input_sync(peaq_poll_dev->input);
 63		peaq_ignore_events_counter = max(1u,
 64			PEAQ_POLL_IGNORE_MS / peaq_poll_dev->poll_interval);
 65	}
 66}
 67
 68/* Some other devices (Shuttle XS35) use the same WMI GUID for other purposes */
 69static const struct dmi_system_id peaq_dmi_table[] __initconst = {
 70	{
 71		.matches = {
 72			DMI_MATCH(DMI_SYS_VENDOR, "PEAQ"),
 73			DMI_MATCH(DMI_PRODUCT_NAME, "PEAQ PMM C1010 MD99187"),
 74		},
 75	},
 76	{}
 77};
 78
 79static int __init peaq_wmi_init(void)
 80{
 81	/* WMI GUID is not unique, also check for a DMI match */
 82	if (!dmi_check_system(peaq_dmi_table))
 83		return -ENODEV;
 84
 85	if (!wmi_has_guid(PEAQ_DOLBY_BUTTON_GUID))
 86		return -ENODEV;
 87
 88	peaq_poll_dev = input_allocate_polled_device();
 89	if (!peaq_poll_dev)
 90		return -ENOMEM;
 91
 92	peaq_poll_dev->poll = peaq_wmi_poll;
 93	peaq_poll_dev->poll_interval = PEAQ_POLL_INTERVAL_MS;
 94	peaq_poll_dev->poll_interval_max = PEAQ_POLL_MAX_MS;
 95	peaq_poll_dev->input->name = "PEAQ WMI hotkeys";
 96	peaq_poll_dev->input->phys = "wmi/input0";
 97	peaq_poll_dev->input->id.bustype = BUS_HOST;
 98	input_set_capability(peaq_poll_dev->input, EV_KEY, KEY_SOUND);
 99
100	return input_register_polled_device(peaq_poll_dev);
101}
102
103static void __exit peaq_wmi_exit(void)
104{
105	input_unregister_polled_device(peaq_poll_dev);
106}
107
108module_init(peaq_wmi_init);
109module_exit(peaq_wmi_exit);
110
111MODULE_DESCRIPTION("PEAQ 2-in-1 WMI hotkey driver");
112MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
113MODULE_LICENSE("GPL");