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 25static 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 43MODULE_AUTHOR("Chen Yu"); 44MODULE_DESCRIPTION("Surface Pro3 Button Driver"); 45MODULE_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 */ 59static const struct acpi_device_id surface_button_device_ids[] = { 60 {SURFACE_PRO3_BUTTON_HID, 0}, 61 {SURFACE_PRO4_BUTTON_HID, 0}, 62 {"", 0}, 63}; 64MODULE_DEVICE_TABLE(acpi, surface_button_device_ids); 65 66struct 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 74static 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 130static 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 139static 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 */ 157static 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 187static 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 242static 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 250static SIMPLE_DEV_PM_OPS(surface_button_pm, 251 surface_button_suspend, surface_button_resume); 252 253static 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 265module_acpi_driver(surface_button_driver); 266