linux/drivers/platform/x86/surfacepro3_button.c
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   1/*
   2 * power/home/volume button support for
   3 * Microsoft Surface Pro 3/4 tablet.
   4 *
   5 * Copyright (c) 2015 Intel Corporation.
   6 * All rights reserved.
   7 *
   8 * This program is free software; you can redistribute it and/or
   9 * modify it under the terms of the GNU General Public License
  10 * as published by the Free Software Foundation; version 2
  11 * of the License.
  12 */
  13
  14#include <linux/kernel.h>
  15#include <linux/module.h>
  16#include <linux/init.h>
  17#include <linux/types.h>
  18#include <linux/input.h>
  19#include <linux/acpi.h>
  20#include <acpi/button.h>
  21
  22#define SURFACE_PRO3_BUTTON_HID         "MSHW0028"
  23#define SURFACE_PRO4_BUTTON_HID         "MSHW0040"
  24#define SURFACE_BUTTON_OBJ_NAME         "VGBI"
  25#define SURFACE_BUTTON_DEVICE_NAME      "Surface Pro 3/4 Buttons"
  26
  27#define SURFACE_BUTTON_NOTIFY_TABLET_MODE       0xc8
  28
  29#define SURFACE_BUTTON_NOTIFY_PRESS_POWER       0xc6
  30#define SURFACE_BUTTON_NOTIFY_RELEASE_POWER     0xc7
  31
  32#define SURFACE_BUTTON_NOTIFY_PRESS_HOME        0xc4
  33#define SURFACE_BUTTON_NOTIFY_RELEASE_HOME      0xc5
  34
  35#define SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_UP   0xc0
  36#define SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_UP 0xc1
  37
  38#define SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_DOWN         0xc2
  39#define SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_DOWN       0xc3
  40
  41ACPI_MODULE_NAME("surface pro 3 button");
  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                /*fall through*/
  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                /*fall through*/
  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                /*fall through*/
 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                /*fall through*/
 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_event(&device->dev, 0);
 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
 149static int surface_button_add(struct acpi_device *device)
 150{
 151        struct surface_button *button;
 152        struct input_dev *input;
 153        const char *hid = acpi_device_hid(device);
 154        char *name;
 155        int error;
 156
 157        if (strncmp(acpi_device_bid(device), SURFACE_BUTTON_OBJ_NAME,
 158            strlen(SURFACE_BUTTON_OBJ_NAME)))
 159                return -ENODEV;
 160
 161        button = kzalloc(sizeof(struct surface_button), GFP_KERNEL);
 162        if (!button)
 163                return -ENOMEM;
 164
 165        device->driver_data = button;
 166        button->input = input = input_allocate_device();
 167        if (!input) {
 168                error = -ENOMEM;
 169                goto err_free_button;
 170        }
 171
 172        name = acpi_device_name(device);
 173        strcpy(name, SURFACE_BUTTON_DEVICE_NAME);
 174        snprintf(button->phys, sizeof(button->phys), "%s/buttons", hid);
 175
 176        input->name = name;
 177        input->phys = button->phys;
 178        input->id.bustype = BUS_HOST;
 179        input->dev.parent = &device->dev;
 180        input_set_capability(input, EV_KEY, KEY_POWER);
 181        input_set_capability(input, EV_KEY, KEY_LEFTMETA);
 182        input_set_capability(input, EV_KEY, KEY_VOLUMEUP);
 183        input_set_capability(input, EV_KEY, KEY_VOLUMEDOWN);
 184
 185        error = input_register_device(input);
 186        if (error)
 187                goto err_free_input;
 188        dev_info(&device->dev,
 189                        "%s [%s]\n", name, acpi_device_bid(device));
 190        return 0;
 191
 192 err_free_input:
 193        input_free_device(input);
 194 err_free_button:
 195        kfree(button);
 196        return error;
 197}
 198
 199static int surface_button_remove(struct acpi_device *device)
 200{
 201        struct surface_button *button = acpi_driver_data(device);
 202
 203        input_unregister_device(button->input);
 204        kfree(button);
 205        return 0;
 206}
 207
 208static SIMPLE_DEV_PM_OPS(surface_button_pm,
 209                surface_button_suspend, surface_button_resume);
 210
 211static struct acpi_driver surface_button_driver = {
 212        .name = "surface_pro3_button",
 213        .class = "SurfacePro3",
 214        .ids = surface_button_device_ids,
 215        .ops = {
 216                .add = surface_button_add,
 217                .remove = surface_button_remove,
 218                .notify = surface_button_notify,
 219        },
 220        .drv.pm = &surface_button_pm,
 221};
 222
 223module_acpi_driver(surface_button_driver);
 224