Linux kernel mirror (for testing)
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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/string.h>
14#include <linux/types.h>
15#include <linux/input.h>
16#include <linux/acpi.h>
17#include <acpi/button.h>
18
19#define SURFACE_PRO3_BUTTON_HID "MSHW0028"
20#define SURFACE_PRO4_BUTTON_HID "MSHW0040"
21#define SURFACE_BUTTON_OBJ_NAME "VGBI"
22#define SURFACE_BUTTON_DEVICE_NAME "Surface Pro 3/4 Buttons"
23
24#define MSHW0040_DSM_REVISION 0x01
25#define MSHW0040_DSM_GET_OMPR 0x02 // get OEM Platform Revision
26static const guid_t MSHW0040_DSM_UUID =
27 GUID_INIT(0x6fd05c69, 0xcde3, 0x49f4, 0x95, 0xed, 0xab, 0x16, 0x65,
28 0x49, 0x80, 0x35);
29
30#define SURFACE_BUTTON_NOTIFY_TABLET_MODE 0xc8
31
32#define SURFACE_BUTTON_NOTIFY_PRESS_POWER 0xc6
33#define SURFACE_BUTTON_NOTIFY_RELEASE_POWER 0xc7
34
35#define SURFACE_BUTTON_NOTIFY_PRESS_HOME 0xc4
36#define SURFACE_BUTTON_NOTIFY_RELEASE_HOME 0xc5
37
38#define SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_UP 0xc0
39#define SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_UP 0xc1
40
41#define SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_DOWN 0xc2
42#define SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_DOWN 0xc3
43
44MODULE_AUTHOR("Chen Yu");
45MODULE_DESCRIPTION("Surface Pro3 Button Driver");
46MODULE_LICENSE("GPL v2");
47
48/*
49 * Power button, Home button, Volume buttons support is supposed to
50 * be covered by drivers/input/misc/soc_button_array.c, which is implemented
51 * according to "Windows ACPI Design Guide for SoC Platforms".
52 * However surface pro3 seems not to obey the specs, instead it uses
53 * device VGBI(MSHW0028) for dispatching the events.
54 * We choose acpi_driver rather than platform_driver/i2c_driver because
55 * although VGBI has an i2c resource connected to i2c controller, it
56 * is not embedded in any i2c controller's scope, thus neither platform_device
57 * will be created, nor i2c_client will be enumerated, we have to use
58 * acpi_driver.
59 */
60static const struct acpi_device_id surface_button_device_ids[] = {
61 {SURFACE_PRO3_BUTTON_HID, 0},
62 {SURFACE_PRO4_BUTTON_HID, 0},
63 {"", 0},
64};
65MODULE_DEVICE_TABLE(acpi, surface_button_device_ids);
66
67struct surface_button {
68 unsigned int type;
69 struct input_dev *input;
70 char phys[32]; /* for input device */
71 unsigned long pushed;
72 bool suspended;
73};
74
75static void surface_button_notify(struct acpi_device *device, u32 event)
76{
77 struct surface_button *button = acpi_driver_data(device);
78 struct input_dev *input;
79 int key_code = KEY_RESERVED;
80 bool pressed = false;
81
82 switch (event) {
83 /* Power button press,release handle */
84 case SURFACE_BUTTON_NOTIFY_PRESS_POWER:
85 pressed = true;
86 fallthrough;
87 case SURFACE_BUTTON_NOTIFY_RELEASE_POWER:
88 key_code = KEY_POWER;
89 break;
90 /* Home button press,release handle */
91 case SURFACE_BUTTON_NOTIFY_PRESS_HOME:
92 pressed = true;
93 fallthrough;
94 case SURFACE_BUTTON_NOTIFY_RELEASE_HOME:
95 key_code = KEY_LEFTMETA;
96 break;
97 /* Volume up button press,release handle */
98 case SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_UP:
99 pressed = true;
100 fallthrough;
101 case SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_UP:
102 key_code = KEY_VOLUMEUP;
103 break;
104 /* Volume down button press,release handle */
105 case SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_DOWN:
106 pressed = true;
107 fallthrough;
108 case SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_DOWN:
109 key_code = KEY_VOLUMEDOWN;
110 break;
111 case SURFACE_BUTTON_NOTIFY_TABLET_MODE:
112 dev_warn_once(&device->dev, "Tablet mode is not supported\n");
113 break;
114 default:
115 dev_info_ratelimited(&device->dev,
116 "Unsupported event [0x%x]\n", event);
117 break;
118 }
119 input = button->input;
120 if (key_code == KEY_RESERVED)
121 return;
122 if (pressed)
123 pm_wakeup_dev_event(&device->dev, 0, button->suspended);
124 if (button->suspended)
125 return;
126 input_report_key(input, key_code, pressed?1:0);
127 input_sync(input);
128}
129
130#ifdef CONFIG_PM_SLEEP
131static int surface_button_suspend(struct device *dev)
132{
133 struct acpi_device *device = to_acpi_device(dev);
134 struct surface_button *button = acpi_driver_data(device);
135
136 button->suspended = true;
137 return 0;
138}
139
140static int surface_button_resume(struct device *dev)
141{
142 struct acpi_device *device = to_acpi_device(dev);
143 struct surface_button *button = acpi_driver_data(device);
144
145 button->suspended = false;
146 return 0;
147}
148#endif
149
150/*
151 * Surface Pro 4 and Surface Book 2 / Surface Pro 2017 use the same device
152 * ID (MSHW0040) for the power/volume buttons. Make sure this is the right
153 * device by checking for the _DSM method and OEM Platform Revision.
154 *
155 * Returns true if the driver should bind to this device, i.e. the device is
156 * either MSWH0028 (Pro 3) or MSHW0040 on a Pro 4 or Book 1.
157 */
158static bool surface_button_check_MSHW0040(struct acpi_device *dev)
159{
160 acpi_handle handle = dev->handle;
161 union acpi_object *result;
162 u64 oem_platform_rev = 0; // valid revisions are nonzero
163
164 // get OEM platform revision
165 result = acpi_evaluate_dsm_typed(handle, &MSHW0040_DSM_UUID,
166 MSHW0040_DSM_REVISION,
167 MSHW0040_DSM_GET_OMPR,
168 NULL, ACPI_TYPE_INTEGER);
169
170 /*
171 * If evaluating the _DSM fails, the method is not present. This means
172 * that we have either MSHW0028 or MSHW0040 on Pro 4 or Book 1, so we
173 * should use this driver. We use revision 0 indicating it is
174 * unavailable.
175 */
176
177 if (result) {
178 oem_platform_rev = result->integer.value;
179 ACPI_FREE(result);
180 }
181
182 dev_dbg(&dev->dev, "OEM Platform Revision %llu\n", oem_platform_rev);
183
184 return oem_platform_rev == 0;
185}
186
187
188static int surface_button_add(struct acpi_device *device)
189{
190 struct surface_button *button;
191 struct input_dev *input;
192 const char *hid = acpi_device_hid(device);
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 strscpy(acpi_device_name(device), SURFACE_BUTTON_DEVICE_NAME);
214 snprintf(button->phys, sizeof(button->phys), "%s/buttons", hid);
215
216 input->name = acpi_device_name(device);
217 input->phys = button->phys;
218 input->id.bustype = BUS_HOST;
219 input->dev.parent = &device->dev;
220 input_set_capability(input, EV_KEY, KEY_POWER);
221 input_set_capability(input, EV_KEY, KEY_LEFTMETA);
222 input_set_capability(input, EV_KEY, KEY_VOLUMEUP);
223 input_set_capability(input, EV_KEY, KEY_VOLUMEDOWN);
224
225 error = input_register_device(input);
226 if (error)
227 goto err_free_input;
228
229 device_init_wakeup(&device->dev, true);
230 dev_info(&device->dev, "%s [%s]\n", acpi_device_name(device),
231 acpi_device_bid(device));
232 return 0;
233
234 err_free_input:
235 input_free_device(input);
236 err_free_button:
237 kfree(button);
238 return error;
239}
240
241static void surface_button_remove(struct acpi_device *device)
242{
243 struct surface_button *button = acpi_driver_data(device);
244
245 input_unregister_device(button->input);
246 kfree(button);
247}
248
249static SIMPLE_DEV_PM_OPS(surface_button_pm,
250 surface_button_suspend, surface_button_resume);
251
252static struct acpi_driver surface_button_driver = {
253 .name = "surface_pro3_button",
254 .class = "SurfacePro3",
255 .ids = surface_button_device_ids,
256 .ops = {
257 .add = surface_button_add,
258 .remove = surface_button_remove,
259 .notify = surface_button_notify,
260 },
261 .drv.pm = &surface_button_pm,
262};
263
264module_acpi_driver(surface_button_driver);