1/*
  2 * power/home/volume button support for
  3 * Microsoft Surface Pro 3/4 tablet.
  4 *
  5 * Copyright (c) 2015 Intel Corporation.
  6 * All rights reserved.
  7 *
  8 * This program is free software; you can redistribute it and/or
  9 * modify it under the terms of the GNU General Public License
 10 * as published by the Free Software Foundation; version 2
 11 * of the License.
 12 */
 13
 14#include <linux/kernel.h>
 15#include <linux/module.h>
 16#include <linux/init.h>
 17#include <linux/types.h>
 18#include <linux/input.h>
 19#include <linux/acpi.h>
 20#include <acpi/button.h>
 21
 22#define SURFACE_PRO3_BUTTON_HID		"MSHW0028"
 23#define SURFACE_PRO4_BUTTON_HID		"MSHW0040"
 24#define SURFACE_BUTTON_OBJ_NAME		"VGBI"
 25#define SURFACE_BUTTON_DEVICE_NAME	"Surface Pro 3/4 Buttons"
 26
 27#define SURFACE_BUTTON_NOTIFY_PRESS_POWER	0xc6
 28#define SURFACE_BUTTON_NOTIFY_RELEASE_POWER	0xc7
 29
 30#define SURFACE_BUTTON_NOTIFY_PRESS_HOME	0xc4
 31#define SURFACE_BUTTON_NOTIFY_RELEASE_HOME	0xc5
 32
 33#define SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_UP	0xc0
 34#define SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_UP	0xc1
 35
 36#define SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_DOWN	0xc2
 37#define SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_DOWN	0xc3
 38
 39ACPI_MODULE_NAME("surface pro 3 button");
 40
 41MODULE_AUTHOR("Chen Yu");
 42MODULE_DESCRIPTION("Surface Pro3 Button Driver");
 43MODULE_LICENSE("GPL v2");
 44
 45/*
 46 * Power button, Home button, Volume buttons support is supposed to
 47 * be covered by drivers/input/misc/soc_button_array.c, which is implemented
 48 * according to "Windows ACPI Design Guide for SoC Platforms".
 49 * However surface pro3 seems not to obey the specs, instead it uses
 50 * device VGBI(MSHW0028) for dispatching the events.
 51 * We choose acpi_driver rather than platform_driver/i2c_driver because
 52 * although VGBI has an i2c resource connected to i2c controller, it
 53 * is not embedded in any i2c controller's scope, thus neither platform_device
 54 * will be created, nor i2c_client will be enumerated, we have to use
 55 * acpi_driver.
 56 */
 57static const struct acpi_device_id surface_button_device_ids[] = {
 58	{SURFACE_PRO3_BUTTON_HID,    0},
 59	{SURFACE_PRO4_BUTTON_HID,    0},
 60	{"", 0},
 61};
 62MODULE_DEVICE_TABLE(acpi, surface_button_device_ids);
 63
 64struct surface_button {
 65	unsigned int type;
 66	struct input_dev *input;
 67	char phys[32];			/* for input device */
 68	unsigned long pushed;
 69	bool suspended;
 70};
 71
 72static void surface_button_notify(struct acpi_device *device, u32 event)
 73{
 74	struct surface_button *button = acpi_driver_data(device);
 75	struct input_dev *input;
 76	int key_code = KEY_RESERVED;
 77	bool pressed = false;
 78
 79	switch (event) {
 80	/* Power button press,release handle */
 81	case SURFACE_BUTTON_NOTIFY_PRESS_POWER:
 82		pressed = true;
 83		/*fall through*/
 84	case SURFACE_BUTTON_NOTIFY_RELEASE_POWER:
 85		key_code = KEY_POWER;
 86		break;
 87	/* Home button press,release handle */
 88	case SURFACE_BUTTON_NOTIFY_PRESS_HOME:
 89		pressed = true;
 90		/*fall through*/
 91	case SURFACE_BUTTON_NOTIFY_RELEASE_HOME:
 92		key_code = KEY_LEFTMETA;
 93		break;
 94	/* Volume up button press,release handle */
 95	case SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_UP:
 96		pressed = true;
 97		/*fall through*/
 98	case SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_UP:
 99		key_code = KEY_VOLUMEUP;
100		break;
101	/* Volume down button press,release handle */
102	case SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_DOWN:
103		pressed = true;
104		/*fall through*/
105	case SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_DOWN:
106		key_code = KEY_VOLUMEDOWN;
107		break;
108	default:
109		dev_info_ratelimited(&device->dev,
110				  "Unsupported event [0x%x]\n", event);
111		break;
112	}
113	input = button->input;
114	if (key_code == KEY_RESERVED)
115		return;
116	if (pressed)
117		pm_wakeup_event(&device->dev, 0);
118	if (button->suspended)
119		return;
120	input_report_key(input, key_code, pressed?1:0);
121	input_sync(input);
122}
123
124#ifdef CONFIG_PM_SLEEP
125static int surface_button_suspend(struct device *dev)
126{
127	struct acpi_device *device = to_acpi_device(dev);
128	struct surface_button *button = acpi_driver_data(device);
129
130	button->suspended = true;
131	return 0;
132}
133
134static int surface_button_resume(struct device *dev)
135{
136	struct acpi_device *device = to_acpi_device(dev);
137	struct surface_button *button = acpi_driver_data(device);
138
139	button->suspended = false;
140	return 0;
141}
142#endif
143
144static int surface_button_add(struct acpi_device *device)
145{
146	struct surface_button *button;
147	struct input_dev *input;
148	const char *hid = acpi_device_hid(device);
149	char *name;
150	int error;
151
152	if (strncmp(acpi_device_bid(device), SURFACE_BUTTON_OBJ_NAME,
153	    strlen(SURFACE_BUTTON_OBJ_NAME)))
154		return -ENODEV;
155
156	button = kzalloc(sizeof(struct surface_button), GFP_KERNEL);
157	if (!button)
158		return -ENOMEM;
159
160	device->driver_data = button;
161	button->input = input = input_allocate_device();
162	if (!input) {
163		error = -ENOMEM;
164		goto err_free_button;
165	}
166
167	name = acpi_device_name(device);
168	strcpy(name, SURFACE_BUTTON_DEVICE_NAME);
169	snprintf(button->phys, sizeof(button->phys), "%s/buttons", hid);
170
171	input->name = name;
172	input->phys = button->phys;
173	input->id.bustype = BUS_HOST;
174	input->dev.parent = &device->dev;
175	input_set_capability(input, EV_KEY, KEY_POWER);
176	input_set_capability(input, EV_KEY, KEY_LEFTMETA);
177	input_set_capability(input, EV_KEY, KEY_VOLUMEUP);
178	input_set_capability(input, EV_KEY, KEY_VOLUMEDOWN);
179
180	error = input_register_device(input);
181	if (error)
182		goto err_free_input;
183	dev_info(&device->dev,
184			"%s [%s]\n", name, acpi_device_bid(device));
185	return 0;
186
187 err_free_input:
188	input_free_device(input);
189 err_free_button:
190	kfree(button);
191	return error;
192}
193
194static int surface_button_remove(struct acpi_device *device)
195{
196	struct surface_button *button = acpi_driver_data(device);
197
198	input_unregister_device(button->input);
199	kfree(button);
200	return 0;
201}
202
203static SIMPLE_DEV_PM_OPS(surface_button_pm,
204		surface_button_suspend, surface_button_resume);
205
206static struct acpi_driver surface_button_driver = {
207	.name = "surface_pro3_button",
208	.class = "SurfacePro3",
209	.ids = surface_button_device_ids,
210	.ops = {
211		.add = surface_button_add,
212		.remove = surface_button_remove,
213		.notify = surface_button_notify,
214	},
215	.drv.pm = &surface_button_pm,
216};
217
218module_acpi_driver(surface_button_driver);