drivers/platform/x86/surfacepro3_button.c

   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 SURFACE_BUTTON_NOTIFY_TABLET_MODE       0xc8
  24
  25 #define SURFACE_BUTTON_NOTIFY_PRESS_POWER       0xc6
  26 #define SURFACE_BUTTON_NOTIFY_RELEASE_POWER     0xc7
  27
  28 #define SURFACE_BUTTON_NOTIFY_PRESS_HOME        0xc4
  29 #define SURFACE_BUTTON_NOTIFY_RELEASE_HOME      0xc5
  30
  31 #define SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_UP   0xc0
  32 #define SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_UP 0xc1
  33
  34 #define SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_DOWN         0xc2
  35 #define SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_DOWN       0xc3
  36
  37 ACPI_MODULE_NAME("surface pro 3 button");
  38
  39 MODULE_AUTHOR("Chen Yu");
  40 MODULE_DESCRIPTION("Surface Pro3 Button Driver");
  41 MODULE_LICENSE("GPL v2");
  42
  43 /*
  44  * Power button, Home button, Volume buttons support is supposed to
  45  * be covered by drivers/input/misc/soc_button_array.c, which is implemented
  46  * according to "Windows ACPI Design Guide for SoC Platforms".
  47  * However surface pro3 seems not to obey the specs, instead it uses
  48  * device VGBI(MSHW0028) for dispatching the events.
  49  * We choose acpi_driver rather than platform_driver/i2c_driver because
  50  * although VGBI has an i2c resource connected to i2c controller, it
  51  * is not embedded in any i2c controller's scope, thus neither platform_device
  52  * will be created, nor i2c_client will be enumerated, we have to use
  53  * acpi_driver.
  54  */
  55 static const struct acpi_device_id surface_button_device_ids[] = {
  56         {SURFACE_PRO3_BUTTON_HID,    0},
  57         {SURFACE_PRO4_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         case SURFACE_BUTTON_NOTIFY_TABLET_MODE:
 107                 dev_warn_once(&device->dev, "Tablet mode is not supported\n");
 108                 break;
 109         default:
 110                 dev_info_ratelimited(&device->dev,
 111                                      "Unsupported event [0x%x]\n", event);
 112                 break;
 113         }
 114         input = button->input;
 115         if (key_code == KEY_RESERVED)
 116                 return;
 117         if (pressed)
 118                 pm_wakeup_dev_event(&device->dev, 0, button->suspended);
 119         if (button->suspended)
 120                 return;
 121         input_report_key(input, key_code, pressed?1:0);
 122         input_sync(input);
 123 }
 124
 125 #ifdef CONFIG_PM_SLEEP
 126 static int surface_button_suspend(struct device *dev)
 127 {
 128         struct acpi_device *device = to_acpi_device(dev);
 129         struct surface_button *button = acpi_driver_data(device);
 130
 131         button->suspended = true;
 132         return 0;
 133 }
 134
 135 static int surface_button_resume(struct device *dev)
 136 {
 137         struct acpi_device *device = to_acpi_device(dev);
 138         struct surface_button *button = acpi_driver_data(device);
 139
 140         button->suspended = false;
 141         return 0;
 142 }
 143 #endif
 144
 145 static int surface_button_add(struct acpi_device *device)
 146 {
 147         struct surface_button *button;
 148         struct input_dev *input;
 149         const char *hid = acpi_device_hid(device);
 150         char *name;
 151         int error;
 152
 153         if (strncmp(acpi_device_bid(device), SURFACE_BUTTON_OBJ_NAME,
 154             strlen(SURFACE_BUTTON_OBJ_NAME)))
 155                 return -ENODEV;
 156
 157         button = kzalloc(sizeof(struct surface_button), GFP_KERNEL);
 158         if (!button)
 159                 return -ENOMEM;
 160
 161         device->driver_data = button;
 162         button->input = input = input_allocate_device();
 163         if (!input) {
 164                 error = -ENOMEM;
 165                 goto err_free_button;
 166         }
 167
 168         name = acpi_device_name(device);
 169         strcpy(name, SURFACE_BUTTON_DEVICE_NAME);
 170         snprintf(button->phys, sizeof(button->phys), "%s/buttons", hid);
 171
 172         input->name = name;
 173         input->phys = button->phys;
 174         input->id.bustype = BUS_HOST;
 175         input->dev.parent = &device->dev;
 176         input_set_capability(input, EV_KEY, KEY_POWER);
 177         input_set_capability(input, EV_KEY, KEY_LEFTMETA);
 178         input_set_capability(input, EV_KEY, KEY_VOLUMEUP);
 179         input_set_capability(input, EV_KEY, KEY_VOLUMEDOWN);
 180
 181         error = input_register_device(input);
 182         if (error)
 183                 goto err_free_input;
 184
 185         device_init_wakeup(&device->dev, true);
 186         dev_info(&device->dev,
 187                         "%s [%s]\n", name, acpi_device_bid(device));
 188         return 0;
 189
 190  err_free_input:
 191         input_free_device(input);
 192  err_free_button:
 193         kfree(button);
 194         return error;
 195 }
 196
 197 static int surface_button_remove(struct acpi_device *device)
 198 {
 199         struct surface_button *button = acpi_driver_data(device);
 200
 201         input_unregister_device(button->input);
 202         kfree(button);
 203         return 0;
 204 }
 205
 206 static SIMPLE_DEV_PM_OPS(surface_button_pm,
 207                 surface_button_suspend, surface_button_resume);
 208
 209 static struct acpi_driver surface_button_driver = {
 210         .name = "surface_pro3_button",
 211         .class = "SurfacePro3",
 212         .ids = surface_button_device_ids,
 213         .ops = {
 214                 .add = surface_button_add,
 215                 .remove = surface_button_remove,
 216                 .notify = surface_button_notify,
 217         },
 218         .drv.pm = &surface_button_pm,
 219 };
 220
 221 module_acpi_driver(surface_button_driver);