// SPDX-License-Identifier: GPL-2.0-only
/*
* power/home/volume button support for
* Microsoft Surface Pro 3/4 tablet.
*
* Copyright (c) 2015 Intel Corporation.
* All rights reserved.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/input.h>
#include <linux/acpi.h>
#include <acpi/button.h>
#define SURFACE_PRO3_BUTTON_HID "MSHW0028"
#define SURFACE_PRO4_BUTTON_HID "MSHW0040"
#define SURFACE_BUTTON_OBJ_NAME "VGBI"
#define SURFACE_BUTTON_DEVICE_NAME "Surface Pro 3/4 Buttons"
#define MSHW0040_DSM_REVISION 0x01
#define MSHW0040_DSM_GET_OMPR 0x02 // get OEM Platform Revision
static const guid_t MSHW0040_DSM_UUID =
GUID_INIT(0x6fd05c69, 0xcde3, 0x49f4, 0x95, 0xed, 0xab, 0x16, 0x65,
0x49, 0x80, 0x35);
#define SURFACE_BUTTON_NOTIFY_TABLET_MODE 0xc8
#define SURFACE_BUTTON_NOTIFY_PRESS_POWER 0xc6
#define SURFACE_BUTTON_NOTIFY_RELEASE_POWER 0xc7
#define SURFACE_BUTTON_NOTIFY_PRESS_HOME 0xc4
#define SURFACE_BUTTON_NOTIFY_RELEASE_HOME 0xc5
#define SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_UP 0xc0
#define SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_UP 0xc1
#define SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_DOWN 0xc2
#define SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_DOWN 0xc3
MODULE_AUTHOR("Chen Yu");
MODULE_DESCRIPTION("Surface Pro3 Button Driver");
MODULE_LICENSE("GPL v2");
/*
* Power button, Home button, Volume buttons support is supposed to
* be covered by drivers/input/misc/soc_button_array.c, which is implemented
* according to "Windows ACPI Design Guide for SoC Platforms".
* However surface pro3 seems not to obey the specs, instead it uses
* device VGBI(MSHW0028) for dispatching the events.
* We choose acpi_driver rather than platform_driver/i2c_driver because
* although VGBI has an i2c resource connected to i2c controller, it
* is not embedded in any i2c controller's scope, thus neither platform_device
* will be created, nor i2c_client will be enumerated, we have to use
* acpi_driver.
*/
static const struct acpi_device_id surface_button_device_ids[] = {
{SURFACE_PRO3_BUTTON_HID, 0},
{SURFACE_PRO4_BUTTON_HID, 0},
{"", 0},
};
MODULE_DEVICE_TABLE(acpi, surface_button_device_ids);
struct surface_button {
unsigned int type;
struct input_dev *input;
char phys[32]; /* for input device */
unsigned long pushed;
bool suspended;
};
static void surface_button_notify(struct acpi_device *device, u32 event)
{
struct surface_button *button = acpi_driver_data(device);
struct input_dev *input;
int key_code = KEY_RESERVED;
bool pressed = false;
switch (event) {
/* Power button press,release handle */
case SURFACE_BUTTON_NOTIFY_PRESS_POWER:
pressed = true;
fallthrough;
case SURFACE_BUTTON_NOTIFY_RELEASE_POWER:
key_code = KEY_POWER;
break;
/* Home button press,release handle */
case SURFACE_BUTTON_NOTIFY_PRESS_HOME:
pressed = true;
fallthrough;
case SURFACE_BUTTON_NOTIFY_RELEASE_HOME:
key_code = KEY_LEFTMETA;
break;
/* Volume up button press,release handle */
case SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_UP:
pressed = true;
fallthrough;
case SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_UP:
key_code = KEY_VOLUMEUP;
break;
/* Volume down button press,release handle */
case SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_DOWN:
pressed = true;
fallthrough;
case SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_DOWN:
key_code = KEY_VOLUMEDOWN;
break;
case SURFACE_BUTTON_NOTIFY_TABLET_MODE:
dev_warn_once(&device->dev, "Tablet mode is not supported\n");
break;
default:
dev_info_ratelimited(&device->dev,
"Unsupported event [0x%x]\n", event);
break;
}
input = button->input;
if (key_code == KEY_RESERVED)
return;
if (pressed)
pm_wakeup_dev_event(&device->dev, 0, button->suspended);
if (button->suspended)
return;
input_report_key(input, key_code, pressed?1:0);
input_sync(input);
}
#ifdef CONFIG_PM_SLEEP
static int surface_button_suspend(struct device *dev)
{
struct acpi_device *device = to_acpi_device(dev);
struct surface_button *button = acpi_driver_data(device);
button->suspended = true;
return 0;
}
static int surface_button_resume(struct device *dev)
{
struct acpi_device *device = to_acpi_device(dev);
struct surface_button *button = acpi_driver_data(device);
button->suspended = false;
return 0;
}
#endif
/*
* Surface Pro 4 and Surface Book 2 / Surface Pro 2017 use the same device
* ID (MSHW0040) for the power/volume buttons. Make sure this is the right
* device by checking for the _DSM method and OEM Platform Revision.
*
* Returns true if the driver should bind to this device, i.e. the device is
* either MSWH0028 (Pro 3) or MSHW0040 on a Pro 4 or Book 1.
*/
static bool surface_button_check_MSHW0040(struct acpi_device *dev)
{
acpi_handle handle = dev->handle;
union acpi_object *result;
u64 oem_platform_rev = 0; // valid revisions are nonzero
// get OEM platform revision
result = acpi_evaluate_dsm_typed(handle, &MSHW0040_DSM_UUID,
MSHW0040_DSM_REVISION,
MSHW0040_DSM_GET_OMPR,
NULL, ACPI_TYPE_INTEGER);
/*
* If evaluating the _DSM fails, the method is not present. This means
* that we have either MSHW0028 or MSHW0040 on Pro 4 or Book 1, so we
* should use this driver. We use revision 0 indicating it is
* unavailable.
*/
if (result) {
oem_platform_rev = result->integer.value;
ACPI_FREE(result);
}
dev_dbg(&dev->dev, "OEM Platform Revision %llu\n", oem_platform_rev);
return oem_platform_rev == 0;
}
static int surface_button_add(struct acpi_device *device)
{
struct surface_button *button;
struct input_dev *input;
const char *hid = acpi_device_hid(device);
char *name;
int error;
if (strncmp(acpi_device_bid(device), SURFACE_BUTTON_OBJ_NAME,
strlen(SURFACE_BUTTON_OBJ_NAME)))
return -ENODEV;
if (!surface_button_check_MSHW0040(device))
return -ENODEV;
button = kzalloc(sizeof(struct surface_button), GFP_KERNEL);
if (!button)
return -ENOMEM;
device->driver_data = button;
button->input = input = input_allocate_device();
if (!input) {
error = -ENOMEM;
goto err_free_button;
}
name = acpi_device_name(device);
strcpy(name, SURFACE_BUTTON_DEVICE_NAME);
snprintf(button->phys, sizeof(button->phys), "%s/buttons", hid);
input->name = name;
input->phys = button->phys;
input->id.bustype = BUS_HOST;
input->dev.parent = &device->dev;
input_set_capability(input, EV_KEY, KEY_POWER);
input_set_capability(input, EV_KEY, KEY_LEFTMETA);
input_set_capability(input, EV_KEY, KEY_VOLUMEUP);
input_set_capability(input, EV_KEY, KEY_VOLUMEDOWN);
error = input_register_device(input);
if (error)
goto err_free_input;
device_init_wakeup(&device->dev, true);
dev_info(&device->dev,
"%s [%s]\n", name, acpi_device_bid(device));
return 0;
err_free_input:
input_free_device(input);
err_free_button:
kfree(button);
return error;
}
static void surface_button_remove(struct acpi_device *device)
{
struct surface_button *button = acpi_driver_data(device);
input_unregister_device(button->input);
kfree(button);
}
static SIMPLE_DEV_PM_OPS(surface_button_pm,
surface_button_suspend, surface_button_resume);
static struct acpi_driver surface_button_driver = {
.name = "surface_pro3_button",
.class = "SurfacePro3",
.ids = surface_button_device_ids,
.ops = {
.add = surface_button_add,
.remove = surface_button_remove,
.notify = surface_button_notify,
},
.drv.pm = &surface_button_pm,
};
module_acpi_driver(surface_button_driver);
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