1// SPDX-License-Identifier: GPL-2.0+
  2/*
  3 *  Intel Virtual Button driver for Windows 8.1+
  4 *
  5 *  Copyright (C) 2016 AceLan Kao <acelan.kao@canonical.com>
  6 *  Copyright (C) 2016 Alex Hung <alex.hung@canonical.com>
  7 */
  8
  9#include <linux/acpi.h>
 10#include <linux/dmi.h>
 11#include <linux/input.h>
 12#include <linux/input/sparse-keymap.h>
 13#include <linux/kernel.h>
 14#include <linux/module.h>
 15#include <linux/platform_device.h>
 16#include <linux/suspend.h>
 17
 18/* When NOT in tablet mode, VGBS returns with the flag 0x40 */
 19#define TABLET_MODE_FLAG 0x40
 20
 21MODULE_LICENSE("GPL");
 22MODULE_AUTHOR("AceLan Kao");
 23
 24static const struct acpi_device_id intel_vbtn_ids[] = {
 25	{"INT33D6", 0},
 26	{"", 0},
 27};
 28
 29/* In theory, these are HID usages. */
 30static const struct key_entry intel_vbtn_keymap[] = {
 31	{ KE_KEY, 0xC0, { KEY_POWER } },	/* power key press */
 32	{ KE_IGNORE, 0xC1, { KEY_POWER } },	/* power key release */
 33	{ KE_KEY, 0xC2, { KEY_LEFTMETA } },		/* 'Windows' key press */
 34	{ KE_KEY, 0xC3, { KEY_LEFTMETA } },		/* 'Windows' key release */
 35	{ KE_KEY, 0xC4, { KEY_VOLUMEUP } },		/* volume-up key press */
 36	{ KE_IGNORE, 0xC5, { KEY_VOLUMEUP } },		/* volume-up key release */
 37	{ KE_KEY, 0xC6, { KEY_VOLUMEDOWN } },		/* volume-down key press */
 38	{ KE_IGNORE, 0xC7, { KEY_VOLUMEDOWN } },	/* volume-down key release */
 39	{ KE_KEY,    0xC8, { KEY_ROTATE_LOCK_TOGGLE } },	/* rotate-lock key press */
 40	{ KE_KEY,    0xC9, { KEY_ROTATE_LOCK_TOGGLE } },	/* rotate-lock key release */
 41	{ KE_SW,     0xCC, { .sw = { SW_TABLET_MODE, 1 } } },	/* Tablet */
 42	{ KE_SW,     0xCD, { .sw = { SW_TABLET_MODE, 0 } } },	/* Laptop */
 43	{ KE_END },
 44};
 45
 46struct intel_vbtn_priv {
 47	struct input_dev *input_dev;
 48	bool wakeup_mode;
 49};
 50
 51static int intel_vbtn_input_setup(struct platform_device *device)
 52{
 53	struct intel_vbtn_priv *priv = dev_get_drvdata(&device->dev);
 54	int ret;
 55
 56	priv->input_dev = devm_input_allocate_device(&device->dev);
 57	if (!priv->input_dev)
 58		return -ENOMEM;
 59
 60	ret = sparse_keymap_setup(priv->input_dev, intel_vbtn_keymap, NULL);
 61	if (ret)
 62		return ret;
 63
 64	priv->input_dev->dev.parent = &device->dev;
 65	priv->input_dev->name = "Intel Virtual Button driver";
 66	priv->input_dev->id.bustype = BUS_HOST;
 67
 68	return input_register_device(priv->input_dev);
 69}
 70
 71static void notify_handler(acpi_handle handle, u32 event, void *context)
 72{
 73	struct platform_device *device = context;
 74	struct intel_vbtn_priv *priv = dev_get_drvdata(&device->dev);
 75	unsigned int val = !(event & 1); /* Even=press, Odd=release */
 76	const struct key_entry *ke_rel;
 77	bool autorelease;
 78
 79	if (priv->wakeup_mode) {
 80		if (sparse_keymap_entry_from_scancode(priv->input_dev, event)) {
 81			pm_wakeup_hard_event(&device->dev);
 82			return;
 83		}
 84		goto out_unknown;
 85	}
 86
 87	/*
 88	 * Even press events are autorelease if there is no corresponding odd
 89	 * release event, or if the odd event is KE_IGNORE.
 90	 */
 91	ke_rel = sparse_keymap_entry_from_scancode(priv->input_dev, event | 1);
 92	autorelease = val && (!ke_rel || ke_rel->type == KE_IGNORE);
 93
 94	if (sparse_keymap_report_event(priv->input_dev, event, val, autorelease))
 95		return;
 96
 97out_unknown:
 98	dev_dbg(&device->dev, "unknown event index 0x%x\n", event);
 99}
100
101static void detect_tablet_mode(struct platform_device *device)
102{
103	const char *chassis_type = dmi_get_system_info(DMI_CHASSIS_TYPE);
104	struct intel_vbtn_priv *priv = dev_get_drvdata(&device->dev);
105	acpi_handle handle = ACPI_HANDLE(&device->dev);
106	struct acpi_buffer vgbs_output = { ACPI_ALLOCATE_BUFFER, NULL };
107	union acpi_object *obj;
108	acpi_status status;
109	int m;
110
111	if (!(chassis_type && strcmp(chassis_type, "31") == 0))
112		goto out;
113
114	status = acpi_evaluate_object(handle, "VGBS", NULL, &vgbs_output);
115	if (ACPI_FAILURE(status))
116		goto out;
117
118	obj = vgbs_output.pointer;
119	if (!(obj && obj->type == ACPI_TYPE_INTEGER))
120		goto out;
121
122	m = !(obj->integer.value & TABLET_MODE_FLAG);
123	input_report_switch(priv->input_dev, SW_TABLET_MODE, m);
124out:
125	kfree(vgbs_output.pointer);
126}
127
128static int intel_vbtn_probe(struct platform_device *device)
129{
130	acpi_handle handle = ACPI_HANDLE(&device->dev);
131	struct intel_vbtn_priv *priv;
132	acpi_status status;
133	int err;
134
135	status = acpi_evaluate_object(handle, "VBDL", NULL, NULL);
136	if (ACPI_FAILURE(status)) {
137		dev_warn(&device->dev, "failed to read Intel Virtual Button driver\n");
138		return -ENODEV;
139	}
140
141	priv = devm_kzalloc(&device->dev, sizeof(*priv), GFP_KERNEL);
142	if (!priv)
143		return -ENOMEM;
144	dev_set_drvdata(&device->dev, priv);
145
146	err = intel_vbtn_input_setup(device);
147	if (err) {
148		pr_err("Failed to setup Intel Virtual Button\n");
149		return err;
150	}
151
152	detect_tablet_mode(device);
153
154	status = acpi_install_notify_handler(handle,
155					     ACPI_DEVICE_NOTIFY,
156					     notify_handler,
157					     device);
158	if (ACPI_FAILURE(status))
159		return -EBUSY;
160
161	device_init_wakeup(&device->dev, true);
162	return 0;
163}
164
165static int intel_vbtn_remove(struct platform_device *device)
166{
167	acpi_handle handle = ACPI_HANDLE(&device->dev);
168
169	device_init_wakeup(&device->dev, false);
170	acpi_remove_notify_handler(handle, ACPI_DEVICE_NOTIFY, notify_handler);
171
172	/*
173	 * Even if we failed to shut off the event stream, we can still
174	 * safely detach from the device.
175	 */
176	return 0;
177}
178
179static int intel_vbtn_pm_prepare(struct device *dev)
180{
181	struct intel_vbtn_priv *priv = dev_get_drvdata(dev);
182
183	priv->wakeup_mode = true;
184	return 0;
185}
186
187static int intel_vbtn_pm_resume(struct device *dev)
188{
189	struct intel_vbtn_priv *priv = dev_get_drvdata(dev);
190
191	priv->wakeup_mode = false;
192	return 0;
193}
194
195static const struct dev_pm_ops intel_vbtn_pm_ops = {
196	.prepare = intel_vbtn_pm_prepare,
197	.resume = intel_vbtn_pm_resume,
198	.restore = intel_vbtn_pm_resume,
199	.thaw = intel_vbtn_pm_resume,
200};
201
202static struct platform_driver intel_vbtn_pl_driver = {
203	.driver = {
204		.name = "intel-vbtn",
205		.acpi_match_table = intel_vbtn_ids,
206		.pm = &intel_vbtn_pm_ops,
207	},
208	.probe = intel_vbtn_probe,
209	.remove = intel_vbtn_remove,
210};
211MODULE_DEVICE_TABLE(acpi, intel_vbtn_ids);
212
213static acpi_status __init
214check_acpi_dev(acpi_handle handle, u32 lvl, void *context, void **rv)
215{
216	const struct acpi_device_id *ids = context;
217	struct acpi_device *dev;
218
219	if (acpi_bus_get_device(handle, &dev) != 0)
220		return AE_OK;
221
222	if (acpi_match_device_ids(dev, ids) == 0)
223		if (acpi_create_platform_device(dev, NULL))
224			dev_info(&dev->dev,
225				 "intel-vbtn: created platform device\n");
226
227	return AE_OK;
228}
229
230static int __init intel_vbtn_init(void)
231{
232	acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
233			    ACPI_UINT32_MAX, check_acpi_dev, NULL,
234			    (void *)intel_vbtn_ids, NULL);
235
236	return platform_driver_register(&intel_vbtn_pl_driver);
237}
238module_init(intel_vbtn_init);
239
240static void __exit intel_vbtn_exit(void)
241{
242	platform_driver_unregister(&intel_vbtn_pl_driver);
243}
244module_exit(intel_vbtn_exit);