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#define DOCK_MODE_FLAG   0x80
 21
 22MODULE_LICENSE("GPL");
 23MODULE_AUTHOR("AceLan Kao");
 24
 25static const struct acpi_device_id intel_vbtn_ids[] = {
 26	{"INT33D6", 0},
 27	{"", 0},
 28};
 29
 30/* In theory, these are HID usages. */
 31static const struct key_entry intel_vbtn_keymap[] = {
 32	{ KE_KEY, 0xC0, { KEY_POWER } },	/* power key press */
 33	{ KE_IGNORE, 0xC1, { KEY_POWER } },	/* power key release */
 34	{ KE_KEY, 0xC2, { KEY_LEFTMETA } },		/* 'Windows' key press */
 35	{ KE_KEY, 0xC3, { KEY_LEFTMETA } },		/* 'Windows' key release */
 36	{ KE_KEY, 0xC4, { KEY_VOLUMEUP } },		/* volume-up key press */
 37	{ KE_IGNORE, 0xC5, { KEY_VOLUMEUP } },		/* volume-up key release */
 38	{ KE_KEY, 0xC6, { KEY_VOLUMEDOWN } },		/* volume-down key press */
 39	{ KE_IGNORE, 0xC7, { KEY_VOLUMEDOWN } },	/* volume-down key release */
 40	{ KE_KEY,    0xC8, { KEY_ROTATE_LOCK_TOGGLE } },	/* rotate-lock key press */
 41	{ KE_KEY,    0xC9, { KEY_ROTATE_LOCK_TOGGLE } },	/* rotate-lock key release */
 42	{ KE_SW,     0xCA, { .sw = { SW_DOCK, 1 } } },		/* Docked */
 43	{ KE_SW,     0xCB, { .sw = { SW_DOCK, 0 } } },		/* Undocked */
 44	{ KE_SW,     0xCC, { .sw = { SW_TABLET_MODE, 1 } } },	/* Tablet */
 45	{ KE_SW,     0xCD, { .sw = { SW_TABLET_MODE, 0 } } },	/* Laptop */
 46	{ KE_END },
 47};
 48
 49struct intel_vbtn_priv {
 50	struct input_dev *input_dev;
 51	bool wakeup_mode;
 52};
 53
 54static int intel_vbtn_input_setup(struct platform_device *device)
 55{
 56	struct intel_vbtn_priv *priv = dev_get_drvdata(&device->dev);
 57	int ret;
 58
 59	priv->input_dev = devm_input_allocate_device(&device->dev);
 60	if (!priv->input_dev)
 61		return -ENOMEM;
 62
 63	ret = sparse_keymap_setup(priv->input_dev, intel_vbtn_keymap, NULL);
 64	if (ret)
 65		return ret;
 66
 67	priv->input_dev->dev.parent = &device->dev;
 68	priv->input_dev->name = "Intel Virtual Button driver";
 69	priv->input_dev->id.bustype = BUS_HOST;
 70
 71	return input_register_device(priv->input_dev);
 72}
 73
 74static void notify_handler(acpi_handle handle, u32 event, void *context)
 75{
 76	struct platform_device *device = context;
 77	struct intel_vbtn_priv *priv = dev_get_drvdata(&device->dev);
 78	unsigned int val = !(event & 1); /* Even=press, Odd=release */
 79	const struct key_entry *ke, *ke_rel;
 80	bool autorelease;
 81
 82	if (priv->wakeup_mode) {
 83		ke = sparse_keymap_entry_from_scancode(priv->input_dev, event);
 84		if (ke) {
 85			pm_wakeup_hard_event(&device->dev);
 86
 87			/*
 88			 * Switch events like tablet mode will wake the device
 89			 * and report the new switch position to the input
 90			 * subsystem.
 91			 */
 92			if (ke->type == KE_SW)
 93				sparse_keymap_report_event(priv->input_dev,
 94							   event,
 95							   val,
 96							   0);
 97			return;
 98		}
 99		goto out_unknown;
100	}
101
102	/*
103	 * Even press events are autorelease if there is no corresponding odd
104	 * release event, or if the odd event is KE_IGNORE.
105	 */
106	ke_rel = sparse_keymap_entry_from_scancode(priv->input_dev, event | 1);
107	autorelease = val && (!ke_rel || ke_rel->type == KE_IGNORE);
108
109	if (sparse_keymap_report_event(priv->input_dev, event, val, autorelease))
110		return;
111
112out_unknown:
113	dev_dbg(&device->dev, "unknown event index 0x%x\n", event);
114}
115
116static void detect_tablet_mode(struct platform_device *device)
117{
118	const char *chassis_type = dmi_get_system_info(DMI_CHASSIS_TYPE);
119	struct intel_vbtn_priv *priv = dev_get_drvdata(&device->dev);
120	acpi_handle handle = ACPI_HANDLE(&device->dev);
121	struct acpi_buffer vgbs_output = { ACPI_ALLOCATE_BUFFER, NULL };
122	union acpi_object *obj;
123	acpi_status status;
124	int m;
125
126	if (!(chassis_type && strcmp(chassis_type, "31") == 0))
127		goto out;
128
129	status = acpi_evaluate_object(handle, "VGBS", NULL, &vgbs_output);
130	if (ACPI_FAILURE(status))
131		goto out;
132
133	obj = vgbs_output.pointer;
134	if (!(obj && obj->type == ACPI_TYPE_INTEGER))
135		goto out;
136
137	m = !(obj->integer.value & TABLET_MODE_FLAG);
138	input_report_switch(priv->input_dev, SW_TABLET_MODE, m);
139	m = (obj->integer.value & DOCK_MODE_FLAG) ? 1 : 0;
140	input_report_switch(priv->input_dev, SW_DOCK, m);
141out:
142	kfree(vgbs_output.pointer);
143}
144
145static int intel_vbtn_probe(struct platform_device *device)
146{
147	acpi_handle handle = ACPI_HANDLE(&device->dev);
148	struct intel_vbtn_priv *priv;
149	acpi_status status;
150	int err;
151
152	status = acpi_evaluate_object(handle, "VBDL", NULL, NULL);
153	if (ACPI_FAILURE(status)) {
154		dev_warn(&device->dev, "failed to read Intel Virtual Button driver\n");
155		return -ENODEV;
156	}
157
158	priv = devm_kzalloc(&device->dev, sizeof(*priv), GFP_KERNEL);
159	if (!priv)
160		return -ENOMEM;
161	dev_set_drvdata(&device->dev, priv);
162
163	err = intel_vbtn_input_setup(device);
164	if (err) {
165		pr_err("Failed to setup Intel Virtual Button\n");
166		return err;
167	}
168
169	detect_tablet_mode(device);
170
171	status = acpi_install_notify_handler(handle,
172					     ACPI_DEVICE_NOTIFY,
173					     notify_handler,
174					     device);
175	if (ACPI_FAILURE(status))
176		return -EBUSY;
177
178	device_init_wakeup(&device->dev, true);
179	/*
180	 * In order for system wakeup to work, the EC GPE has to be marked as
181	 * a wakeup one, so do that here (this setting will persist, but it has
182	 * no effect until the wakeup mask is set for the EC GPE).
183	 */
184	acpi_ec_mark_gpe_for_wake();
185	return 0;
186}
187
188static int intel_vbtn_remove(struct platform_device *device)
189{
190	acpi_handle handle = ACPI_HANDLE(&device->dev);
191
192	device_init_wakeup(&device->dev, false);
193	acpi_remove_notify_handler(handle, ACPI_DEVICE_NOTIFY, notify_handler);
194
195	/*
196	 * Even if we failed to shut off the event stream, we can still
197	 * safely detach from the device.
198	 */
199	return 0;
200}
201
202static int intel_vbtn_pm_prepare(struct device *dev)
203{
204	if (device_may_wakeup(dev)) {
205		struct intel_vbtn_priv *priv = dev_get_drvdata(dev);
206
207		priv->wakeup_mode = true;
208	}
209	return 0;
210}
211
212static void intel_vbtn_pm_complete(struct device *dev)
213{
214	struct intel_vbtn_priv *priv = dev_get_drvdata(dev);
215
216	priv->wakeup_mode = false;
217}
218
219static int intel_vbtn_pm_resume(struct device *dev)
220{
221	intel_vbtn_pm_complete(dev);
222	return 0;
223}
224
225static const struct dev_pm_ops intel_vbtn_pm_ops = {
226	.prepare = intel_vbtn_pm_prepare,
227	.complete = intel_vbtn_pm_complete,
228	.resume = intel_vbtn_pm_resume,
229	.restore = intel_vbtn_pm_resume,
230	.thaw = intel_vbtn_pm_resume,
231};
232
233static struct platform_driver intel_vbtn_pl_driver = {
234	.driver = {
235		.name = "intel-vbtn",
236		.acpi_match_table = intel_vbtn_ids,
237		.pm = &intel_vbtn_pm_ops,
238	},
239	.probe = intel_vbtn_probe,
240	.remove = intel_vbtn_remove,
241};
242MODULE_DEVICE_TABLE(acpi, intel_vbtn_ids);
243
244static acpi_status __init
245check_acpi_dev(acpi_handle handle, u32 lvl, void *context, void **rv)
246{
247	const struct acpi_device_id *ids = context;
248	struct acpi_device *dev;
249
250	if (acpi_bus_get_device(handle, &dev) != 0)
251		return AE_OK;
252
253	if (acpi_match_device_ids(dev, ids) == 0)
254		if (acpi_create_platform_device(dev, NULL))
255			dev_info(&dev->dev,
256				 "intel-vbtn: created platform device\n");
257
258	return AE_OK;
259}
260
261static int __init intel_vbtn_init(void)
262{
263	acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
264			    ACPI_UINT32_MAX, check_acpi_dev, NULL,
265			    (void *)intel_vbtn_ids, NULL);
266
267	return platform_driver_register(&intel_vbtn_pl_driver);
268}
269module_init(intel_vbtn_init);
270
271static void __exit intel_vbtn_exit(void)
272{
273	platform_driver_unregister(&intel_vbtn_pl_driver);
274}
275module_exit(intel_vbtn_exit);