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_PRESS_POWER       0xc6
  28 #define SURFACE_BUTTON_NOTIFY_RELEASE_POWER     0xc7
  29
  30 #define SURFACE_BUTTON_NOTIFY_PRESS_HOME        0xc4
  31 #define SURFACE_BUTTON_NOTIFY_RELEASE_HOME      0xc5
  32
  33 #define SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_UP   0xc0
  34 #define SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_UP 0xc1
  35
  36 #define SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_DOWN 0xc2
  37 #define SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_DOWN       0xc3
  38
  39 ACPI_MODULE_NAME("surface pro 3 button");
  40
  41 MODULE_AUTHOR("Chen Yu");
  42 MODULE_DESCRIPTION("Surface Pro3 Button Driver");
  43 MODULE_LICENSE("GPL v2");
  44
  45 /*
  46  * Power button, Home button, Volume buttons support is supposed to
  47  * be covered by drivers/input/misc/soc_button_array.c, which is implemented
  48  * according to "Windows ACPI Design Guide for SoC Platforms".
  49  * However surface pro3 seems not to obey the specs, instead it uses
  50  * device VGBI(MSHW0028) for dispatching the events.
  51  * We choose acpi_driver rather than platform_driver/i2c_driver because
  52  * although VGBI has an i2c resource connected to i2c controller, it
  53  * is not embedded in any i2c controller's scope, thus neither platform_device
  54  * will be created, nor i2c_client will be enumerated, we have to use
  55  * acpi_driver.
  56  */
  57 static const struct acpi_device_id surface_button_device_ids[] = {
  58         {SURFACE_PRO3_BUTTON_HID,    0},
  59         {SURFACE_PRO4_BUTTON_HID,    0},
  60         {"", 0},
  61 };
  62 MODULE_DEVICE_TABLE(acpi, surface_button_device_ids);
  63
  64 struct surface_button {
  65         unsigned int type;
  66         struct input_dev *input;
  67         char phys[32];                  /* for input device */
  68         unsigned long pushed;
  69         bool suspended;
  70 };
  71
  72 static void surface_button_notify(struct acpi_device *device, u32 event)
  73 {
  74         struct surface_button *button = acpi_driver_data(device);
  75         struct input_dev *input;
  76         int key_code = KEY_RESERVED;
  77         bool pressed = false;
  78
  79         switch (event) {
  80         /* Power button press,release handle */
  81         case SURFACE_BUTTON_NOTIFY_PRESS_POWER:
  82                 pressed = true;
  83                 /*fall through*/
  84         case SURFACE_BUTTON_NOTIFY_RELEASE_POWER:
  85                 key_code = KEY_POWER;
  86                 break;
  87         /* Home button press,release handle */
  88         case SURFACE_BUTTON_NOTIFY_PRESS_HOME:
  89                 pressed = true;
  90                 /*fall through*/
  91         case SURFACE_BUTTON_NOTIFY_RELEASE_HOME:
  92                 key_code = KEY_LEFTMETA;
  93                 break;
  94         /* Volume up button press,release handle */
  95         case SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_UP:
  96                 pressed = true;
  97                 /*fall through*/
  98         case SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_UP:
  99                 key_code = KEY_VOLUMEUP;
 100                 break;
 101         /* Volume down button press,release handle */
 102         case SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_DOWN:
 103                 pressed = true;
 104                 /*fall through*/
 105         case SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_DOWN:
 106                 key_code = KEY_VOLUMEDOWN;
 107                 break;
 108         default:
 109                 dev_info_ratelimited(&device->dev,
 110                                   "Unsupported event [0x%x]\n", event);
 111                 break;
 112         }
 113         input = button->input;
 114         if (key_code == KEY_RESERVED)
 115                 return;
 116         if (pressed)
 117                 pm_wakeup_event(&device->dev, 0);
 118         if (button->suspended)
 119                 return;
 120         input_report_key(input, key_code, pressed?1:0);
 121         input_sync(input);
 122 }
 123
 124 #ifdef CONFIG_PM_SLEEP
 125 static int surface_button_suspend(struct device *dev)
 126 {
 127         struct acpi_device *device = to_acpi_device(dev);
 128         struct surface_button *button = acpi_driver_data(device);
 129
 130         button->suspended = true;
 131         return 0;
 132 }
 133
 134 static int surface_button_resume(struct device *dev)
 135 {
 136         struct acpi_device *device = to_acpi_device(dev);
 137         struct surface_button *button = acpi_driver_data(device);
 138
 139         button->suspended = false;
 140         return 0;
 141 }
 142 #endif
 143
 144 static int surface_button_add(struct acpi_device *device)
 145 {
 146         struct surface_button *button;
 147         struct input_dev *input;
 148         const char *hid = acpi_device_hid(device);
 149         char *name;
 150         int error;
 151
 152         if (strncmp(acpi_device_bid(device), SURFACE_BUTTON_OBJ_NAME,
 153             strlen(SURFACE_BUTTON_OBJ_NAME)))
 154                 return -ENODEV;
 155
 156         button = kzalloc(sizeof(struct surface_button), GFP_KERNEL);
 157         if (!button)
 158                 return -ENOMEM;
 159
 160         device->driver_data = button;
 161         button->input = input = input_allocate_device();
 162         if (!input) {
 163                 error = -ENOMEM;
 164                 goto err_free_button;
 165         }
 166
 167         name = acpi_device_name(device);
 168         strcpy(name, SURFACE_BUTTON_DEVICE_NAME);
 169         snprintf(button->phys, sizeof(button->phys), "%s/buttons", hid);
 170
 171         input->name = name;
 172         input->phys = button->phys;
 173         input->id.bustype = BUS_HOST;
 174         input->dev.parent = &device->dev;
 175         input_set_capability(input, EV_KEY, KEY_POWER);
 176         input_set_capability(input, EV_KEY, KEY_LEFTMETA);
 177         input_set_capability(input, EV_KEY, KEY_VOLUMEUP);
 178         input_set_capability(input, EV_KEY, KEY_VOLUMEDOWN);
 179
 180         error = input_register_device(input);
 181         if (error)
 182                 goto err_free_input;
 183         dev_info(&device->dev,
 184                         "%s [%s]\n", name, acpi_device_bid(device));
 185         return 0;
 186
 187  err_free_input:
 188         input_free_device(input);
 189  err_free_button:
 190         kfree(button);
 191         return error;
 192 }
 193
 194 static int surface_button_remove(struct acpi_device *device)
 195 {
 196         struct surface_button *button = acpi_driver_data(device);
 197
 198         input_unregister_device(button->input);
 199         kfree(button);
 200         return 0;
 201 }
 202
 203 static SIMPLE_DEV_PM_OPS(surface_button_pm,
 204                 surface_button_suspend, surface_button_resume);
 205
 206 static struct acpi_driver surface_button_driver = {
 207         .name = "surface_pro3_button",
 208         .class = "SurfacePro3",
 209         .ids = surface_button_device_ids,
 210         .ops = {
 211                 .add = surface_button_add,
 212                 .remove = surface_button_remove,
 213                 .notify = surface_button_notify,
 214         },
 215         .drv.pm = &surface_button_pm,
 216 };
 217
 218 module_acpi_driver(surface_button_driver);