drivers/platform/surface/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 MSHW0040_DSM_REVISION           0x01
  24 #define MSHW0040_DSM_GET_OMPR           0x02    // get OEM Platform Revision
  25 static const guid_t MSHW0040_DSM_UUID =
  26         GUID_INIT(0x6fd05c69, 0xcde3, 0x49f4, 0x95, 0xed, 0xab, 0x16, 0x65,
  27                   0x49, 0x80, 0x35);
  28
  29 #define SURFACE_BUTTON_NOTIFY_TABLET_MODE       0xc8
  30
  31 #define SURFACE_BUTTON_NOTIFY_PRESS_POWER       0xc6
  32 #define SURFACE_BUTTON_NOTIFY_RELEASE_POWER     0xc7
  33
  34 #define SURFACE_BUTTON_NOTIFY_PRESS_HOME        0xc4
  35 #define SURFACE_BUTTON_NOTIFY_RELEASE_HOME      0xc5
  36
  37 #define SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_UP   0xc0
  38 #define SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_UP 0xc1
  39
  40 #define SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_DOWN         0xc2
  41 #define SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_DOWN       0xc3
  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                 fallthrough;
  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                 fallthrough;
  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                 fallthrough;
 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                 fallthrough;
 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_dev_event(&device->dev, 0, button->suspended);
 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 /*
 150  * Surface Pro 4 and Surface Book 2 / Surface Pro 2017 use the same device
 151  * ID (MSHW0040) for the power/volume buttons. Make sure this is the right
 152  * device by checking for the _DSM method and OEM Platform Revision.
 153  *
 154  * Returns true if the driver should bind to this device, i.e. the device is
 155  * either MSWH0028 (Pro 3) or MSHW0040 on a Pro 4 or Book 1.
 156  */
 157 static bool surface_button_check_MSHW0040(struct acpi_device *dev)
 158 {
 159         acpi_handle handle = dev->handle;
 160         union acpi_object *result;
 161         u64 oem_platform_rev = 0;       // valid revisions are nonzero
 162
 163         // get OEM platform revision
 164         result = acpi_evaluate_dsm_typed(handle, &MSHW0040_DSM_UUID,
 165                                          MSHW0040_DSM_REVISION,
 166                                          MSHW0040_DSM_GET_OMPR,
 167                                          NULL, ACPI_TYPE_INTEGER);
 168
 169         /*
 170          * If evaluating the _DSM fails, the method is not present. This means
 171          * that we have either MSHW0028 or MSHW0040 on Pro 4 or Book 1, so we
 172          * should use this driver. We use revision 0 indicating it is
 173          * unavailable.
 174          */
 175
 176         if (result) {
 177                 oem_platform_rev = result->integer.value;
 178                 ACPI_FREE(result);
 179         }
 180
 181         dev_dbg(&dev->dev, "OEM Platform Revision %llu\n", oem_platform_rev);
 182
 183         return oem_platform_rev == 0;
 184 }
 185
 186
 187 static int surface_button_add(struct acpi_device *device)
 188 {
 189         struct surface_button *button;
 190         struct input_dev *input;
 191         const char *hid = acpi_device_hid(device);
 192         char *name;
 193         int error;
 194
 195         if (strncmp(acpi_device_bid(device), SURFACE_BUTTON_OBJ_NAME,
 196             strlen(SURFACE_BUTTON_OBJ_NAME)))
 197                 return -ENODEV;
 198
 199         if (!surface_button_check_MSHW0040(device))
 200                 return -ENODEV;
 201
 202         button = kzalloc(sizeof(struct surface_button), GFP_KERNEL);
 203         if (!button)
 204                 return -ENOMEM;
 205
 206         device->driver_data = button;
 207         button->input = input = input_allocate_device();
 208         if (!input) {
 209                 error = -ENOMEM;
 210                 goto err_free_button;
 211         }
 212
 213         name = acpi_device_name(device);
 214         strcpy(name, SURFACE_BUTTON_DEVICE_NAME);
 215         snprintf(button->phys, sizeof(button->phys), "%s/buttons", hid);
 216
 217         input->name = name;
 218         input->phys = button->phys;
 219         input->id.bustype = BUS_HOST;
 220         input->dev.parent = &device->dev;
 221         input_set_capability(input, EV_KEY, KEY_POWER);
 222         input_set_capability(input, EV_KEY, KEY_LEFTMETA);
 223         input_set_capability(input, EV_KEY, KEY_VOLUMEUP);
 224         input_set_capability(input, EV_KEY, KEY_VOLUMEDOWN);
 225
 226         error = input_register_device(input);
 227         if (error)
 228                 goto err_free_input;
 229
 230         device_init_wakeup(&device->dev, true);
 231         dev_info(&device->dev,
 232                         "%s [%s]\n", name, acpi_device_bid(device));
 233         return 0;
 234
 235  err_free_input:
 236         input_free_device(input);
 237  err_free_button:
 238         kfree(button);
 239         return error;
 240 }
 241
 242 static void surface_button_remove(struct acpi_device *device)
 243 {
 244         struct surface_button *button = acpi_driver_data(device);
 245
 246         input_unregister_device(button->input);
 247         kfree(button);
 248 }
 249
 250 static SIMPLE_DEV_PM_OPS(surface_button_pm,
 251                 surface_button_suspend, surface_button_resume);
 252
 253 static struct acpi_driver surface_button_driver = {
 254         .name = "surface_pro3_button",
 255         .class = "SurfacePro3",
 256         .ids = surface_button_device_ids,
 257         .ops = {
 258                 .add = surface_button_add,
 259                 .remove = surface_button_remove,
 260                 .notify = surface_button_notify,
 261         },
 262         .drv.pm = &surface_button_pm,
 263 };
 264
 265 module_acpi_driver(surface_button_driver);