drivers/platform/x86/surfacepro3_button.c

   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
  41 ACPI_MODULE_NAME("surface pro 3 button");
  42
  43 MODULE_AUTHOR("Chen Yu");
  44 MODULE_DESCRIPTION("Surface Pro3 Button Driver");
  45 MODULE_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  */
  59 static const struct acpi_device_id surface_button_device_ids[] = {
  60         {SURFACE_PRO3_BUTTON_HID,    0},
  61         {SURFACE_PRO4_BUTTON_HID,    0},
  62         {"", 0},
  63 };
  64 MODULE_DEVICE_TABLE(acpi, surface_button_device_ids);
  65
  66 struct 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
  74 static 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
 130 static 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
 139 static 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 static 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
 199 static 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
 208 static SIMPLE_DEV_PM_OPS(surface_button_pm,
 209                 surface_button_suspend, surface_button_resume);
 210
 211 static 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
 223 module_acpi_driver(surface_button_driver);