linux/drivers/platform/x86/peaq-wmi.c
Dan Carpenter 890f658c10 platform/x86: peaq-wmi: silence a static checker warning
There is a harmless static checker warning here that unsigned values are
always >= 0.  The code looks like:

	if (peaq_ignore_events_counter && --peaq_ignore_events_counter >= 0)

The first part of the condition ensures that we never wrap around so the
code works as intended.  I've tweaked it slightly to avoid the warning.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
2017-07-25 09:56:37 -07:00

101 lines
2.9 KiB
C

/*
* PEAQ 2-in-1 WMI hotkey driver
* Copyright (C) 2017 Hans de Goede <hdegoede@redhat.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/acpi.h>
#include <linux/input-polldev.h>
#include <linux/kernel.h>
#include <linux/module.h>
#define PEAQ_DOLBY_BUTTON_GUID "ABBC0F6F-8EA1-11D1-00A0-C90629100000"
#define PEAQ_DOLBY_BUTTON_METHOD_ID 5
#define PEAQ_POLL_INTERVAL_MS 250
#define PEAQ_POLL_IGNORE_MS 500
#define PEAQ_POLL_MAX_MS 1000
MODULE_ALIAS("wmi:"PEAQ_DOLBY_BUTTON_GUID);
static unsigned int peaq_ignore_events_counter;
static struct input_polled_dev *peaq_poll_dev;
/*
* The Dolby button (yes really a Dolby button) causes an ACPI variable to get
* set on both press and release. The WMI method checks and clears that flag.
* So for a press + release we will get back One from the WMI method either once
* (if polling after the release) or twice (polling between press and release).
* We ignore events for 0.5s after the first event to avoid reporting 2 presses.
*/
static void peaq_wmi_poll(struct input_polled_dev *dev)
{
union acpi_object obj;
acpi_status status;
u32 dummy = 0;
struct acpi_buffer input = { sizeof(dummy), &dummy };
struct acpi_buffer output = { sizeof(obj), &obj };
status = wmi_evaluate_method(PEAQ_DOLBY_BUTTON_GUID, 1,
PEAQ_DOLBY_BUTTON_METHOD_ID,
&input, &output);
if (ACPI_FAILURE(status))
return;
if (obj.type != ACPI_TYPE_INTEGER) {
dev_err(&peaq_poll_dev->input->dev,
"Error WMBC did not return an integer\n");
return;
}
if (peaq_ignore_events_counter && peaq_ignore_events_counter--)
return;
if (obj.integer.value) {
input_event(peaq_poll_dev->input, EV_KEY, KEY_SOUND, 1);
input_sync(peaq_poll_dev->input);
input_event(peaq_poll_dev->input, EV_KEY, KEY_SOUND, 0);
input_sync(peaq_poll_dev->input);
peaq_ignore_events_counter = max(1u,
PEAQ_POLL_IGNORE_MS / peaq_poll_dev->poll_interval);
}
}
static int __init peaq_wmi_init(void)
{
if (!wmi_has_guid(PEAQ_DOLBY_BUTTON_GUID))
return -ENODEV;
peaq_poll_dev = input_allocate_polled_device();
if (!peaq_poll_dev)
return -ENOMEM;
peaq_poll_dev->poll = peaq_wmi_poll;
peaq_poll_dev->poll_interval = PEAQ_POLL_INTERVAL_MS;
peaq_poll_dev->poll_interval_max = PEAQ_POLL_MAX_MS;
peaq_poll_dev->input->name = "PEAQ WMI hotkeys";
peaq_poll_dev->input->phys = "wmi/input0";
peaq_poll_dev->input->id.bustype = BUS_HOST;
input_set_capability(peaq_poll_dev->input, EV_KEY, KEY_SOUND);
return input_register_polled_device(peaq_poll_dev);
}
static void __exit peaq_wmi_exit(void)
{
if (!wmi_has_guid(PEAQ_DOLBY_BUTTON_GUID))
return;
input_unregister_polled_device(peaq_poll_dev);
}
module_init(peaq_wmi_init);
module_exit(peaq_wmi_exit);
MODULE_DESCRIPTION("PEAQ 2-in-1 WMI hotkey driver");
MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
MODULE_LICENSE("GPL");