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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * power/home/volume button support for4 * 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 0x0124#define MSHW0040_DSM_GET_OMPR 0x02 // get OEM Platform Revision25static 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 0xc830 31#define SURFACE_BUTTON_NOTIFY_PRESS_POWER 0xc632#define SURFACE_BUTTON_NOTIFY_RELEASE_POWER 0xc733 34#define SURFACE_BUTTON_NOTIFY_PRESS_HOME 0xc435#define SURFACE_BUTTON_NOTIFY_RELEASE_HOME 0xc536 37#define SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_UP 0xc038#define SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_UP 0xc139 40#define SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_DOWN 0xc241#define SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_DOWN 0xc342 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 to49 * be covered by drivers/input/misc/soc_button_array.c, which is implemented50 * according to "Windows ACPI Design Guide for SoC Platforms".51 * However surface pro3 seems not to obey the specs, instead it uses52 * device VGBI(MSHW0028) for dispatching the events.53 * We choose acpi_driver rather than platform_driver/i2c_driver because54 * although VGBI has an i2c resource connected to i2c controller, it55 * is not embedded in any i2c controller's scope, thus neither platform_device56 * will be created, nor i2c_client will be enumerated, we have to use57 * 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_SLEEP130static 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#endif148 149/*150 * Surface Pro 4 and Surface Book 2 / Surface Pro 2017 use the same device151 * ID (MSHW0040) for the power/volume buttons. Make sure this is the right152 * 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 is155 * 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 nonzero162 163 // get OEM platform revision164 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 means171 * that we have either MSHW0028 or MSHW0040 on Pro 4 or Book 1, so we172 * should use this driver. We use revision 0 indicating it is173 * 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