kernel/drivers/platform/x86/surfacepro3_button.c

   1 /*
   2  * power/home/volume button support for
   3  * Microsoft Surface Pro 3 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_BUTTON_HID              "MSHW0028"
  23 #define SURFACE_BUTTON_OBJ_NAME         "VGBI"
  24 #define SURFACE_BUTTON_DEVICE_NAME      "Surface Pro 3 Buttons"
  25
  26 #define SURFACE_BUTTON_NOTIFY_PRESS_POWER       0xc6
  27 #define SURFACE_BUTTON_NOTIFY_RELEASE_POWER     0xc7
  28
  29 #define SURFACE_BUTTON_NOTIFY_PRESS_HOME        0xc4
  30 #define SURFACE_BUTTON_NOTIFY_RELEASE_HOME      0xc5
  31
  32 #define SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_UP   0xc0
  33 #define SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_UP 0xc1
  34
  35 #define SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_DOWN 0xc2
  36 #define SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_DOWN       0xc3
  37
  38 ACPI_MODULE_NAME("surface pro 3 button");
  39
  40 MODULE_AUTHOR("Chen Yu");
  41 MODULE_DESCRIPTION("Surface Pro3 Button Driver");
  42 MODULE_LICENSE("GPL v2");
  43
  44 /*
  45  * Power button, Home button, Volume buttons support is supposed to
  46  * be covered by drivers/input/misc/soc_button_array.c, which is implemented
  47  * according to "Windows ACPI Design Guide for SoC Platforms".
  48  * However surface pro3 seems not to obey the specs, instead it uses
  49  * device VGBI(MSHW0028) for dispatching the events.
  50  * We choose acpi_driver rather than platform_driver/i2c_driver because
  51  * although VGBI has an i2c resource connected to i2c controller, it
  52  * is not embedded in any i2c controller's scope, thus neither platform_device
  53  * will be created, nor i2c_client will be enumerated, we have to use
  54  * acpi_driver.
  55  */
  56 static const struct acpi_device_id surface_button_device_ids[] = {
  57         {SURFACE_BUTTON_HID,    0},
  58         {"", 0},
  59 };
  60 MODULE_DEVICE_TABLE(acpi, surface_button_device_ids);
  61
  62 struct surface_button {
  63         unsigned int type;
  64         struct input_dev *input;
  65         char phys[32];                  /* for input device */
  66         unsigned long pushed;
  67         bool suspended;
  68 };
  69
  70 static void surface_button_notify(struct acpi_device *device, u32 event)
  71 {
  72         struct surface_button *button = acpi_driver_data(device);
  73         struct input_dev *input;
  74         int key_code = KEY_RESERVED;
  75         bool pressed = false;
  76
  77         switch (event) {
  78         /* Power button press,release handle */
  79         case SURFACE_BUTTON_NOTIFY_PRESS_POWER:
  80                 pressed = true;
  81                 /*fall through*/
  82         case SURFACE_BUTTON_NOTIFY_RELEASE_POWER:
  83                 key_code = KEY_POWER;
  84                 break;
  85         /* Home button press,release handle */
  86         case SURFACE_BUTTON_NOTIFY_PRESS_HOME:
  87                 pressed = true;
  88                 /*fall through*/
  89         case SURFACE_BUTTON_NOTIFY_RELEASE_HOME:
  90                 key_code = KEY_LEFTMETA;
  91                 break;
  92         /* Volume up button press,release handle */
  93         case SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_UP:
  94                 pressed = true;
  95                 /*fall through*/
  96         case SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_UP:
  97                 key_code = KEY_VOLUMEUP;
  98                 break;
  99         /* Volume down button press,release handle */
 100         case SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_DOWN:
 101                 pressed = true;
 102                 /*fall through*/
 103         case SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_DOWN:
 104                 key_code = KEY_VOLUMEDOWN;
 105                 break;
 106         default:
 107                 dev_info_ratelimited(&device->dev,
 108                                   "Unsupported event [0x%x]\n", event);
 109                 break;
 110         }
 111         input = button->input;
 112         if (KEY_RESERVED == key_code)
 113                 return;
 114         if (pressed)
 115                 pm_wakeup_event(&device->dev, 0);
 116         if (button->suspended)
 117                 return;
 118         input_report_key(input, key_code, pressed?1:0);
 119         input_sync(input);
 120 }
 121
 122 #ifdef CONFIG_PM_SLEEP
 123 static int surface_button_suspend(struct device *dev)
 124 {
 125         struct acpi_device *device = to_acpi_device(dev);
 126         struct surface_button *button = acpi_driver_data(device);
 127
 128         button->suspended = true;
 129         return 0;
 130 }
 131
 132 static int surface_button_resume(struct device *dev)
 133 {
 134         struct acpi_device *device = to_acpi_device(dev);
 135         struct surface_button *button = acpi_driver_data(device);
 136
 137         button->suspended = false;
 138         return 0;
 139 }
 140 #endif
 141
 142 static int surface_button_add(struct acpi_device *device)
 143 {
 144         struct surface_button *button;
 145         struct input_dev *input;
 146         const char *hid = acpi_device_hid(device);
 147         char *name;
 148         int error;
 149
 150         if (strncmp(acpi_device_bid(device), SURFACE_BUTTON_OBJ_NAME,
 151             strlen(SURFACE_BUTTON_OBJ_NAME)))
 152                 return -ENODEV;
 153
 154         button = kzalloc(sizeof(struct surface_button), GFP_KERNEL);
 155         if (!button)
 156                 return -ENOMEM;
 157
 158         device->driver_data = button;
 159         button->input = input = input_allocate_device();
 160         if (!input) {
 161                 error = -ENOMEM;
 162                 goto err_free_button;
 163         }
 164
 165         name = acpi_device_name(device);
 166         strcpy(name, SURFACE_BUTTON_DEVICE_NAME);
 167         snprintf(button->phys, sizeof(button->phys), "%s/buttons", hid);
 168
 169         input->name = name;
 170         input->phys = button->phys;
 171         input->id.bustype = BUS_HOST;
 172         input->dev.parent = &device->dev;
 173         input_set_capability(input, EV_KEY, KEY_POWER);
 174         input_set_capability(input, EV_KEY, KEY_LEFTMETA);
 175         input_set_capability(input, EV_KEY, KEY_VOLUMEUP);
 176         input_set_capability(input, EV_KEY, KEY_VOLUMEDOWN);
 177
 178         error = input_register_device(input);
 179         if (error)
 180                 goto err_free_input;
 181         dev_info(&device->dev,
 182                         "%s [%s]\n", name, acpi_device_bid(device));
 183         return 0;
 184
 185  err_free_input:
 186         input_free_device(input);
 187  err_free_button:
 188         kfree(button);
 189         return error;
 190 }
 191
 192 static int surface_button_remove(struct acpi_device *device)
 193 {
 194         struct surface_button *button = acpi_driver_data(device);
 195
 196         input_unregister_device(button->input);
 197         kfree(button);
 198         return 0;
 199 }
 200
 201 static SIMPLE_DEV_PM_OPS(surface_button_pm,
 202                 surface_button_suspend, surface_button_resume);
 203
 204 static struct acpi_driver surface_button_driver = {
 205         .name = "surface_pro3_button",
 206         .class = "SurfacePro3",
 207         .ids = surface_button_device_ids,
 208         .ops = {
 209                 .add = surface_button_add,
 210                 .remove = surface_button_remove,
 211                 .notify = surface_button_notify,
 212         },
 213         .drv.pm = &surface_button_pm,
 214 };
 215
 216 module_acpi_driver(surface_button_driver);