dell-wmi-aio.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* WMI hotkeys support for Dell All-In-One series
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/input.h>
#include <linux/input/sparse-keymap.h>
#include <linux/acpi.h>
#include <linux/string.h>
MODULE_DESCRIPTION("WMI hotkeys driver for Dell All-In-One series");
MODULE_LICENSE("GPL");
#define EVENT_GUID1 "284A0E6B-380E-472A-921F-E52786257FB4"
#define EVENT_GUID2 "02314822-307C-4F66-BF0E-48AEAEB26CC8"
struct dell_wmi_event {
u16 length;
/* 0x000: A hot key pressed or an event occurred
* 0x00F: A sequence of hot keys are pressed */
u16 type;
u16 event[];
};
static const char *dell_wmi_aio_guids[] = {
EVENT_GUID1,
EVENT_GUID2,
NULL
};
MODULE_ALIAS("wmi:"EVENT_GUID1);
MODULE_ALIAS("wmi:"EVENT_GUID2);
static const struct key_entry dell_wmi_aio_keymap[] = {
{ KE_KEY, 0xc0, { KEY_VOLUMEUP } },
{ KE_KEY, 0xc1, { KEY_VOLUMEDOWN } },
{ KE_KEY, 0xe030, { KEY_VOLUMEUP } },
{ KE_KEY, 0xe02e, { KEY_VOLUMEDOWN } },
{ KE_KEY, 0xe020, { KEY_MUTE } },
{ KE_KEY, 0xe027, { KEY_DISPLAYTOGGLE } },
{ KE_KEY, 0xe006, { KEY_BRIGHTNESSUP } },
{ KE_KEY, 0xe005, { KEY_BRIGHTNESSDOWN } },
{ KE_KEY, 0xe00b, { KEY_SWITCHVIDEOMODE } },
{ KE_END, 0 }
};
static struct input_dev *dell_wmi_aio_input_dev;
/*
* The new WMI event data format will follow the dell_wmi_event structure
* So, we will check if the buffer matches the format
*/
static bool dell_wmi_aio_event_check(u8 *buffer, int length)
{
struct dell_wmi_event *event = (struct dell_wmi_event *)buffer;
if (event == NULL || length < 6)
return false;
if ((event->type == 0 || event->type == 0xf) &&
event->length >= 2)
return true;
return false;
}
static void dell_wmi_aio_notify(u32 value, void *context)
{
struct acpi_buffer response = { ACPI_ALLOCATE_BUFFER, NULL };
union acpi_object *obj;
struct dell_wmi_event *event;
acpi_status status;
status = wmi_get_event_data(value, &response);
if (status != AE_OK) {
pr_info("bad event status 0x%x\n", status);
return;
}
obj = (union acpi_object *)response.pointer;
if (obj) {
unsigned int scancode = 0;
switch (obj->type) {
case ACPI_TYPE_INTEGER:
/* Most All-In-One correctly return integer scancode */
scancode = obj->integer.value;
sparse_keymap_report_event(dell_wmi_aio_input_dev,
scancode, 1, true);
break;
case ACPI_TYPE_BUFFER:
if (dell_wmi_aio_event_check(obj->buffer.pointer,
obj->buffer.length)) {
event = (struct dell_wmi_event *)
obj->buffer.pointer;
scancode = event->event[0];
} else {
/* Broken machines return the scancode in a
buffer */
if (obj->buffer.pointer &&
obj->buffer.length > 0)
scancode = obj->buffer.pointer[0];
}
if (scancode)
sparse_keymap_report_event(
dell_wmi_aio_input_dev,
scancode, 1, true);
break;
}
}
kfree(obj);
}
static int __init dell_wmi_aio_input_setup(void)
{
int err;
dell_wmi_aio_input_dev = input_allocate_device();
if (!dell_wmi_aio_input_dev)
return -ENOMEM;
dell_wmi_aio_input_dev->name = "Dell AIO WMI hotkeys";
dell_wmi_aio_input_dev->phys = "wmi/input0";
dell_wmi_aio_input_dev->id.bustype = BUS_HOST;
err = sparse_keymap_setup(dell_wmi_aio_input_dev,
dell_wmi_aio_keymap, NULL);
if (err) {
pr_err("Unable to setup input device keymap\n");
goto err_free_dev;
}
err = input_register_device(dell_wmi_aio_input_dev);
if (err) {
pr_info("Unable to register input device\n");
goto err_free_dev;
}
return 0;
err_free_dev:
input_free_device(dell_wmi_aio_input_dev);
return err;
}
static const char *dell_wmi_aio_find(void)
{
int i;
for (i = 0; dell_wmi_aio_guids[i] != NULL; i++)
if (wmi_has_guid(dell_wmi_aio_guids[i]))
return dell_wmi_aio_guids[i];
return NULL;
}
static int __init dell_wmi_aio_init(void)
{
int err;
const char *guid;
guid = dell_wmi_aio_find();
if (!guid) {
pr_warn("No known WMI GUID found\n");
return -ENXIO;
}
err = dell_wmi_aio_input_setup();
if (err)
return err;
err = wmi_install_notify_handler(guid, dell_wmi_aio_notify, NULL);
if (err) {
pr_err("Unable to register notify handler - %d\n", err);
input_unregister_device(dell_wmi_aio_input_dev);
return err;
}
return 0;
}
static void __exit dell_wmi_aio_exit(void)
{
const char *guid;
guid = dell_wmi_aio_find();
wmi_remove_notify_handler(guid);
input_unregister_device(dell_wmi_aio_input_dev);
}
module_init(dell_wmi_aio_init);
module_exit(dell_wmi_aio_exit);