LXR linux/drivers/platform/surface/surfacepro3

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * power/home/volume button support for
   4 * Microsoft Surface Pro 3/4 tablet.
   5 *
   6 * Copyright (c) 2015 Intel Corporation.
   7 * All rights reserved.
   8 */
   9
  10#include <linux/kernel.h>
  11#include <linux/module.h>
  12#include <linux/init.h>
  13#include <linux/types.h>
  14#include <linux/input.h>
  15#include <linux/acpi.h>
  16#include <acpi/button.h>
  17
  18#define SURFACE_PRO3_BUTTON_HID         "MSHW0028"
  19#define SURFACE_PRO4_BUTTON_HID         "MSHW0040"
  20#define SURFACE_BUTTON_OBJ_NAME         "VGBI"
  21#define SURFACE_BUTTON_DEVICE_NAME      "Surface Pro 3/4 Buttons"
  22
  23#define MSHW0040_DSM_REVISION           0x01
  24#define MSHW0040_DSM_GET_OMPR           0x02    // get OEM Platform Revision
  25static const guid_t MSHW0040_DSM_UUID =
  26        GUID_INIT(0x6fd05c69, 0xcde3, 0x49f4, 0x95, 0xed, 0xab, 0x16, 0x65,
  27                  0x49, 0x80, 0x35);
  28
  29#define SURFACE_BUTTON_NOTIFY_TABLET_MODE       0xc8
  30
  31#define SURFACE_BUTTON_NOTIFY_PRESS_POWER       0xc6
  32#define SURFACE_BUTTON_NOTIFY_RELEASE_POWER     0xc7
  33
  34#define SURFACE_BUTTON_NOTIFY_PRESS_HOME        0xc4
  35#define SURFACE_BUTTON_NOTIFY_RELEASE_HOME      0xc5
  36
  37#define SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_UP   0xc0
  38#define SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_UP 0xc1
  39
  40#define SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_DOWN         0xc2
  41#define SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_DOWN       0xc3
  42
  43MODULE_AUTHOR("Chen Yu");
  44MODULE_DESCRIPTION("Surface Pro3 Button Driver");
  45MODULE_LICENSE("GPL v2");
  46
  47/*
  48 * Power button, Home button, Volume buttons support is supposed to
  49 * be covered by drivers/input/misc/soc_button_array.c, which is implemented
  50 * according to "Windows ACPI Design Guide for SoC Platforms".
  51 * However surface pro3 seems not to obey the specs, instead it uses
  52 * device VGBI(MSHW0028) for dispatching the events.
  53 * We choose acpi_driver rather than platform_driver/i2c_driver because
  54 * although VGBI has an i2c resource connected to i2c controller, it
  55 * is not embedded in any i2c controller's scope, thus neither platform_device
  56 * will be created, nor i2c_client will be enumerated, we have to use
  57 * acpi_driver.
  58 */
  59static const struct acpi_device_id surface_button_device_ids[] = {
  60        {SURFACE_PRO3_BUTTON_HID,    0},
  61        {SURFACE_PRO4_BUTTON_HID,    0},
  62        {"", 0},
  63};
  64MODULE_DEVICE_TABLE(acpi, surface_button_device_ids);
  65
  66struct surface_button {
  67        unsigned int type;
  68        struct input_dev *input;
  69        char phys[32];                  /* for input device */
  70        unsigned long pushed;
  71        bool suspended;
  72};
  73
  74static void surface_button_notify(struct acpi_device *device, u32 event)
  75{
  76        struct surface_button *button = acpi_driver_data(device);
  77        struct input_dev *input;
  78        int key_code = KEY_RESERVED;
  79        bool pressed = false;
  80
  81        switch (event) {
  82        /* Power button press,release handle */
  83        case SURFACE_BUTTON_NOTIFY_PRESS_POWER:
  84                pressed = true;
  85                fallthrough;
  86        case SURFACE_BUTTON_NOTIFY_RELEASE_POWER:
  87                key_code = KEY_POWER;
  88                break;
  89        /* Home button press,release handle */
  90        case SURFACE_BUTTON_NOTIFY_PRESS_HOME:
  91                pressed = true;
  92                fallthrough;
  93        case SURFACE_BUTTON_NOTIFY_RELEASE_HOME:
  94                key_code = KEY_LEFTMETA;
  95                break;
  96        /* Volume up button press,release handle */
  97        case SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_UP:
  98                pressed = true;
  99                fallthrough;
 100        case SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_UP:
 101                key_code = KEY_VOLUMEUP;
 102                break;
 103        /* Volume down button press,release handle */
 104        case SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_DOWN:
 105                pressed = true;
 106                fallthrough;
 107        case SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_DOWN:
 108                key_code = KEY_VOLUMEDOWN;
 109                break;
 110        case SURFACE_BUTTON_NOTIFY_TABLET_MODE:
 111                dev_warn_once(&device->dev, "Tablet mode is not supported\n");
 112                break;
 113        default:
 114                dev_info_ratelimited(&device->dev,
 115                                     "Unsupported event [0x%x]\n", event);
 116                break;
 117        }
 118        input = button->input;
 119        if (key_code == KEY_RESERVED)
 120                return;
 121        if (pressed)
 122                pm_wakeup_dev_event(&device->dev, 0, button->suspended);
 123        if (button->suspended)
 124                return;
 125        input_report_key(input, key_code, pressed?1:0);
 126        input_sync(input);
 127}
 128
 129#ifdef CONFIG_PM_SLEEP
 130static int surface_button_suspend(struct device *dev)
 131{
 132        struct acpi_device *device = to_acpi_device(dev);
 133        struct surface_button *button = acpi_driver_data(device);
 134
 135        button->suspended = true;
 136        return 0;
 137}
 138
 139static int surface_button_resume(struct device *dev)
 140{
 141        struct acpi_device *device = to_acpi_device(dev);
 142        struct surface_button *button = acpi_driver_data(device);
 143
 144        button->suspended = false;
 145        return 0;
 146}
 147#endif
 148
 149/*
 150 * Surface Pro 4 and Surface Book 2 / Surface Pro 2017 use the same device
 151 * ID (MSHW0040) for the power/volume buttons. Make sure this is the right
 152 * device by checking for the _DSM method and OEM Platform Revision.
 153 *
 154 * Returns true if the driver should bind to this device, i.e. the device is
 155 * either MSWH0028 (Pro 3) or MSHW0040 on a Pro 4 or Book 1.
 156 */
 157static bool surface_button_check_MSHW0040(struct acpi_device *dev)
 158{
 159        acpi_handle handle = dev->handle;
 160        union acpi_object *result;
 161        u64 oem_platform_rev = 0;       // valid revisions are nonzero
 162
 163        // get OEM platform revision
 164        result = acpi_evaluate_dsm_typed(handle, &MSHW0040_DSM_UUID,
 165                                         MSHW0040_DSM_REVISION,
 166                                         MSHW0040_DSM_GET_OMPR,
 167                                         NULL, ACPI_TYPE_INTEGER);
 168
 169        /*
 170         * If evaluating the _DSM fails, the method is not present. This means
 171         * that we have either MSHW0028 or MSHW0040 on Pro 4 or Book 1, so we
 172         * should use this driver. We use revision 0 indicating it is
 173         * unavailable.
 174         */
 175
 176        if (result) {
 177                oem_platform_rev = result->integer.value;
 178                ACPI_FREE(result);
 179        }
 180
 181        dev_dbg(&dev->dev, "OEM Platform Revision %llu\n", oem_platform_rev);
 182
 183        return oem_platform_rev == 0;
 184}
 185
 186
 187static int surface_button_add(struct acpi_device *device)
 188{
 189        struct surface_button *button;
 190        struct input_dev *input;
 191        const char *hid = acpi_device_hid(device);
 192        char *name;
 193        int error;
 194
 195        if (strncmp(acpi_device_bid(device), SURFACE_BUTTON_OBJ_NAME,
 196            strlen(SURFACE_BUTTON_OBJ_NAME)))
 197                return -ENODEV;
 198
 199        if (!surface_button_check_MSHW0040(device))
 200                return -ENODEV;
 201
 202        button = kzalloc(sizeof(struct surface_button), GFP_KERNEL);
 203        if (!button)
 204                return -ENOMEM;
 205
 206        device->driver_data = button;
 207        button->input = input = input_allocate_device();
 208        if (!input) {
 209                error = -ENOMEM;
 210                goto err_free_button;
 211        }
 212
 213        name = acpi_device_name(device);
 214        strcpy(name, SURFACE_BUTTON_DEVICE_NAME);
 215        snprintf(button->phys, sizeof(button->phys), "%s/buttons", hid);
 216
 217        input->name = name;
 218        input->phys = button->phys;
 219        input->id.bustype = BUS_HOST;
 220        input->dev.parent = &device->dev;
 221        input_set_capability(input, EV_KEY, KEY_POWER);
 222        input_set_capability(input, EV_KEY, KEY_LEFTMETA);
 223        input_set_capability(input, EV_KEY, KEY_VOLUMEUP);
 224        input_set_capability(input, EV_KEY, KEY_VOLUMEDOWN);
 225
 226        error = input_register_device(input);
 227        if (error)
 228                goto err_free_input;
 229
 230        device_init_wakeup(&device->dev, true);
 231        dev_info(&device->dev,
 232                        "%s [%s]\n", name, acpi_device_bid(device));
 233        return 0;
 234
 235 err_free_input:
 236        input_free_device(input);
 237 err_free_button:
 238        kfree(button);
 239        return error;
 240}
 241
 242static int surface_button_remove(struct acpi_device *device)
 243{
 244        struct surface_button *button = acpi_driver_data(device);
 245
 246        input_unregister_device(button->input);
 247        kfree(button);
 248        return 0;
 249}
 250
 251static SIMPLE_DEV_PM_OPS(surface_button_pm,
 252                surface_button_suspend, surface_button_resume);
 253
 254static struct acpi_driver surface_button_driver = {
 255        .name = "surface_pro3_button",
 256        .class = "SurfacePro3",
 257        .ids = surface_button_device_ids,
 258        .ops = {
 259                .add = surface_button_add,
 260                .remove = surface_button_remove,
 261                .notify = surface_button_notify,
 262        },
 263        .drv.pm = &surface_button_pm,
 264};
 265
 266module_acpi_driver(surface_button_driver);
 267