root/drivers/platform/x86/surfacepro3_button.c

DEFINITIONS

1. surface_button_notify
2. surface_button_suspend
3. surface_button_resume
4. surface_button_check_MSHW0040
5. surface_button_add
6. surface_button_remove

   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 ACPI_MODULE_NAME("surface pro 3 button");
  44 
  45 MODULE_AUTHOR("Chen Yu");
  46 MODULE_DESCRIPTION("Surface Pro3 Button Driver");
  47 MODULE_LICENSE("GPL v2");
  48 
  49 /*
  50  * Power button, Home button, Volume buttons support is supposed to
  51  * be covered by drivers/input/misc/soc_button_array.c, which is implemented
  52  * according to "Windows ACPI Design Guide for SoC Platforms".
  53  * However surface pro3 seems not to obey the specs, instead it uses
  54  * device VGBI(MSHW0028) for dispatching the events.
  55  * We choose acpi_driver rather than platform_driver/i2c_driver because
  56  * although VGBI has an i2c resource connected to i2c controller, it
  57  * is not embedded in any i2c controller's scope, thus neither platform_device
  58  * will be created, nor i2c_client will be enumerated, we have to use
  59  * acpi_driver.
  60  */
  61 static const struct acpi_device_id surface_button_device_ids[] = {
  62         {SURFACE_PRO3_BUTTON_HID,    0},
  63         {SURFACE_PRO4_BUTTON_HID,    0},
  64         {"", 0},
  65 };
  66 MODULE_DEVICE_TABLE(acpi, surface_button_device_ids);
  67 
  68 struct surface_button {
  69         unsigned int type;
  70         struct input_dev *input;
  71         char phys[32];                  /* for input device */
  72         unsigned long pushed;
  73         bool suspended;
  74 };
  75 
  76 static void surface_button_notify(struct acpi_device *device, u32 event)
  77 {
  78         struct surface_button *button = acpi_driver_data(device);
  79         struct input_dev *input;
  80         int key_code = KEY_RESERVED;
  81         bool pressed = false;
  82 
  83         switch (event) {
  84         /* Power button press,release handle */
  85         case SURFACE_BUTTON_NOTIFY_PRESS_POWER:
  86                 pressed = true;
  87                 /*fall through*/
  88         case SURFACE_BUTTON_NOTIFY_RELEASE_POWER:
  89                 key_code = KEY_POWER;
  90                 break;
  91         /* Home button press,release handle */
  92         case SURFACE_BUTTON_NOTIFY_PRESS_HOME:
  93                 pressed = true;
  94                 /*fall through*/
  95         case SURFACE_BUTTON_NOTIFY_RELEASE_HOME:
  96                 key_code = KEY_LEFTMETA;
  97                 break;
  98         /* Volume up button press,release handle */
  99         case SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_UP:
 100                 pressed = true;
 101                 /*fall through*/
 102         case SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_UP:
 103                 key_code = KEY_VOLUMEUP;
 104                 break;
 105         /* Volume down button press,release handle */
 106         case SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_DOWN:
 107                 pressed = true;
 108                 /*fall through*/
 109         case SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_DOWN:
 110                 key_code = KEY_VOLUMEDOWN;
 111                 break;
 112         case SURFACE_BUTTON_NOTIFY_TABLET_MODE:
 113                 dev_warn_once(&device->dev, "Tablet mode is not supported\n");
 114                 break;
 115         default:
 116                 dev_info_ratelimited(&device->dev,
 117                                      "Unsupported event [0x%x]\n", event);
 118                 break;
 119         }
 120         input = button->input;
 121         if (key_code == KEY_RESERVED)
 122                 return;
 123         if (pressed)
 124                 pm_wakeup_dev_event(&device->dev, 0, button->suspended);
 125         if (button->suspended)
 126                 return;
 127         input_report_key(input, key_code, pressed?1:0);
 128         input_sync(input);
 129 }
 130 
 131 #ifdef CONFIG_PM_SLEEP
 132 static int surface_button_suspend(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 = true;
 138         return 0;
 139 }
 140 
 141 static int surface_button_resume(struct device *dev)
 142 {
 143         struct acpi_device *device = to_acpi_device(dev);
 144         struct surface_button *button = acpi_driver_data(device);
 145 
 146         button->suspended = false;
 147         return 0;
 148 }
 149 #endif
 150 
 151 /*
 152  * Surface Pro 4 and Surface Book 2 / Surface Pro 2017 use the same device
 153  * ID (MSHW0040) for the power/volume buttons. Make sure this is the right
 154  * device by checking for the _DSM method and OEM Platform Revision.
 155  *
 156  * Returns true if the driver should bind to this device, i.e. the device is
 157  * either MSWH0028 (Pro 3) or MSHW0040 on a Pro 4 or Book 1.
 158  */
 159 static bool surface_button_check_MSHW0040(struct acpi_device *dev)
 160 {
 161         acpi_handle handle = dev->handle;
 162         union acpi_object *result;
 163         u64 oem_platform_rev = 0;       // valid revisions are nonzero
 164 
 165         // get OEM platform revision
 166         result = acpi_evaluate_dsm_typed(handle, &MSHW0040_DSM_UUID,
 167                                          MSHW0040_DSM_REVISION,
 168                                          MSHW0040_DSM_GET_OMPR,
 169                                          NULL, ACPI_TYPE_INTEGER);
 170 
 171         /*
 172          * If evaluating the _DSM fails, the method is not present. This means
 173          * that we have either MSHW0028 or MSHW0040 on Pro 4 or Book 1, so we
 174          * should use this driver. We use revision 0 indicating it is
 175          * unavailable.
 176          */
 177 
 178         if (result) {
 179                 oem_platform_rev = result->integer.value;
 180                 ACPI_FREE(result);
 181         }
 182 
 183         dev_dbg(&dev->dev, "OEM Platform Revision %llu\n", oem_platform_rev);
 184 
 185         return oem_platform_rev == 0;
 186 }
 187 
 188 
 189 static int surface_button_add(struct acpi_device *device)
 190 {
 191         struct surface_button *button;
 192         struct input_dev *input;
 193         const char *hid = acpi_device_hid(device);
 194         char *name;
 195         int error;
 196 
 197         if (strncmp(acpi_device_bid(device), SURFACE_BUTTON_OBJ_NAME,
 198             strlen(SURFACE_BUTTON_OBJ_NAME)))
 199                 return -ENODEV;
 200 
 201         if (!surface_button_check_MSHW0040(device))
 202                 return -ENODEV;
 203 
 204         button = kzalloc(sizeof(struct surface_button), GFP_KERNEL);
 205         if (!button)
 206                 return -ENOMEM;
 207 
 208         device->driver_data = button;
 209         button->input = input = input_allocate_device();
 210         if (!input) {
 211                 error = -ENOMEM;
 212                 goto err_free_button;
 213         }
 214 
 215         name = acpi_device_name(device);
 216         strcpy(name, SURFACE_BUTTON_DEVICE_NAME);
 217         snprintf(button->phys, sizeof(button->phys), "%s/buttons", hid);
 218 
 219         input->name = name;
 220         input->phys = button->phys;
 221         input->id.bustype = BUS_HOST;
 222         input->dev.parent = &device->dev;
 223         input_set_capability(input, EV_KEY, KEY_POWER);
 224         input_set_capability(input, EV_KEY, KEY_LEFTMETA);
 225         input_set_capability(input, EV_KEY, KEY_VOLUMEUP);
 226         input_set_capability(input, EV_KEY, KEY_VOLUMEDOWN);
 227 
 228         error = input_register_device(input);
 229         if (error)
 230                 goto err_free_input;
 231 
 232         device_init_wakeup(&device->dev, true);
 233         dev_info(&device->dev,
 234                         "%s [%s]\n", name, acpi_device_bid(device));
 235         return 0;
 236 
 237  err_free_input:
 238         input_free_device(input);
 239  err_free_button:
 240         kfree(button);
 241         return error;
 242 }
 243 
 244 static int surface_button_remove(struct acpi_device *device)
 245 {
 246         struct surface_button *button = acpi_driver_data(device);
 247 
 248         input_unregister_device(button->input);
 249         kfree(button);
 250         return 0;
 251 }
 252 
 253 static SIMPLE_DEV_PM_OPS(surface_button_pm,
 254                 surface_button_suspend, surface_button_resume);
 255 
 256 static struct acpi_driver surface_button_driver = {
 257         .name = "surface_pro3_button",
 258         .class = "SurfacePro3",
 259         .ids = surface_button_device_ids,
 260         .ops = {
 261                 .add = surface_button_add,
 262                 .remove = surface_button_remove,
 263                 .notify = surface_button_notify,
 264         },
 265         .drv.pm = &surface_button_pm,
 266 };
 267 
 268 module_acpi_driver(surface_button_driver);