1/*
  2 *  Intel HID event driver for Windows 8
  3 *
  4 *  Copyright (C) 2015 Alex Hung <alex.hung@canonical.com>
  5 *  Copyright (C) 2015 Andrew Lutomirski <luto@kernel.org>
  6 *
  7 *  This program is free software; you can redistribute it and/or modify
  8 *  it under the terms of the GNU General Public License as published by
  9 *  the Free Software Foundation; either version 2 of the License, or
 10 *  (at your option) any later version.
 11 *
 12 *  This program is distributed in the hope that it will be useful,
 13 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 14 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 15 *  GNU General Public License for more details.
 16 *
 17 */
 18
 19#include <linux/kernel.h>
 20#include <linux/module.h>
 21#include <linux/init.h>
 22#include <linux/input.h>
 23#include <linux/platform_device.h>
 24#include <linux/input/sparse-keymap.h>
 25#include <linux/acpi.h>
 26#include <acpi/acpi_bus.h>
 27
 28MODULE_LICENSE("GPL");
 29MODULE_AUTHOR("Alex Hung");
 30
 31static const struct acpi_device_id intel_hid_ids[] = {
 32	{"INT33D5", 0},
 33	{"", 0},
 34};
 35
 36/* In theory, these are HID usages. */
 37static const struct key_entry intel_hid_keymap[] = {
 38	/* 1: LSuper (Page 0x07, usage 0xE3) -- unclear what to do */
 39	/* 2: Toggle SW_ROTATE_LOCK -- easy to implement if seen in wild */
 40	{ KE_KEY, 3, { KEY_NUMLOCK } },
 41	{ KE_KEY, 4, { KEY_HOME } },
 42	{ KE_KEY, 5, { KEY_END } },
 43	{ KE_KEY, 6, { KEY_PAGEUP } },
 44	{ KE_KEY, 7, { KEY_PAGEDOWN } },
 45	{ KE_KEY, 8, { KEY_RFKILL } },
 46	{ KE_KEY, 9, { KEY_POWER } },
 47	{ KE_KEY, 11, { KEY_SLEEP } },
 48	/* 13 has two different meanings in the spec -- ignore it. */
 49	{ KE_KEY, 14, { KEY_STOPCD } },
 50	{ KE_KEY, 15, { KEY_PLAYPAUSE } },
 51	{ KE_KEY, 16, { KEY_MUTE } },
 52	{ KE_KEY, 17, { KEY_VOLUMEUP } },
 53	{ KE_KEY, 18, { KEY_VOLUMEDOWN } },
 54	{ KE_KEY, 19, { KEY_BRIGHTNESSUP } },
 55	{ KE_KEY, 20, { KEY_BRIGHTNESSDOWN } },
 56	/* 27: wake -- needs special handling */
 57	{ KE_END },
 58};
 59
 60struct intel_hid_priv {
 61	struct input_dev *input_dev;
 62};
 63
 64static int intel_hid_set_enable(struct device *device, int enable)
 65{
 66	union acpi_object arg0 = { ACPI_TYPE_INTEGER };
 67	struct acpi_object_list args = { 1, &arg0 };
 68	acpi_status status;
 69
 70	arg0.integer.value = enable;
 71	status = acpi_evaluate_object(ACPI_HANDLE(device), "HDSM", &args, NULL);
 72	if (!ACPI_SUCCESS(status)) {
 73		dev_warn(device, "failed to %sable hotkeys\n",
 74			 enable ? "en" : "dis");
 75		return -EIO;
 76	}
 77
 78	return 0;
 79}
 80
 81static int intel_hid_pl_suspend_handler(struct device *device)
 82{
 83	intel_hid_set_enable(device, 0);
 84	return 0;
 85}
 86
 87static int intel_hid_pl_resume_handler(struct device *device)
 88{
 89	intel_hid_set_enable(device, 1);
 90	return 0;
 91}
 92
 93static const struct dev_pm_ops intel_hid_pl_pm_ops = {
 94	.freeze  = intel_hid_pl_suspend_handler,
 95	.restore  = intel_hid_pl_resume_handler,
 96	.suspend  = intel_hid_pl_suspend_handler,
 97	.resume  = intel_hid_pl_resume_handler,
 98};
 99
100static int intel_hid_input_setup(struct platform_device *device)
101{
102	struct intel_hid_priv *priv = dev_get_drvdata(&device->dev);
103	int ret;
104
105	priv->input_dev = input_allocate_device();
106	if (!priv->input_dev)
107		return -ENOMEM;
108
109	ret = sparse_keymap_setup(priv->input_dev, intel_hid_keymap, NULL);
110	if (ret)
111		goto err_free_device;
112
113	priv->input_dev->dev.parent = &device->dev;
114	priv->input_dev->name = "Intel HID events";
115	priv->input_dev->id.bustype = BUS_HOST;
116	set_bit(KEY_RFKILL, priv->input_dev->keybit);
117
118	ret = input_register_device(priv->input_dev);
119	if (ret)
120		goto err_free_device;
121
122	return 0;
123
124err_free_device:
125		input_free_device(priv->input_dev);
126		return ret;
127}
128
129static void intel_hid_input_destroy(struct platform_device *device)
130{
131	struct intel_hid_priv *priv = dev_get_drvdata(&device->dev);
132
133	input_unregister_device(priv->input_dev);
134}
135
136static void notify_handler(acpi_handle handle, u32 event, void *context)
137{
138	struct platform_device *device = context;
139	struct intel_hid_priv *priv = dev_get_drvdata(&device->dev);
140	unsigned long long ev_index;
141	acpi_status status;
142
143	/* The platform spec only defines one event code: 0xC0. */
144	if (event != 0xc0) {
145		dev_warn(&device->dev, "received unknown event (0x%x)\n",
146			 event);
147		return;
148	}
149
150	status = acpi_evaluate_integer(handle, "HDEM", NULL, &ev_index);
151	if (!ACPI_SUCCESS(status)) {
152		dev_warn(&device->dev, "failed to get event index\n");
153		return;
154	}
155
156	if (!sparse_keymap_report_event(priv->input_dev, ev_index, 1, true))
157		dev_info(&device->dev, "unknown event index 0x%llx\n",
158			 ev_index);
159}
160
161static int intel_hid_probe(struct platform_device *device)
162{
163	acpi_handle handle = ACPI_HANDLE(&device->dev);
164	struct intel_hid_priv *priv;
165	unsigned long long mode;
166	acpi_status status;
167	int err;
168
169	status = acpi_evaluate_integer(handle, "HDMM", NULL, &mode);
170	if (!ACPI_SUCCESS(status)) {
171		dev_warn(&device->dev, "failed to read mode\n");
172		return -ENODEV;
173	}
174
175	if (mode != 0) {
176		/*
177		 * This driver only implements "simple" mode.  There appear
178		 * to be no other modes, but we should be paranoid and check
179		 * for compatibility.
180		 */
181		dev_info(&device->dev, "platform is not in simple mode\n");
182		return -ENODEV;
183	}
184
185	priv = devm_kzalloc(&device->dev, sizeof(*priv), GFP_KERNEL);
186	if (!priv)
187		return -ENOMEM;
188	dev_set_drvdata(&device->dev, priv);
189
190	err = intel_hid_input_setup(device);
191	if (err) {
192		pr_err("Failed to setup Intel HID hotkeys\n");
193		return err;
194	}
195
196	status = acpi_install_notify_handler(handle,
197					     ACPI_DEVICE_NOTIFY,
198					     notify_handler,
199					     device);
200	if (ACPI_FAILURE(status)) {
201		err = -EBUSY;
202		goto err_remove_input;
203	}
204
205	err = intel_hid_set_enable(&device->dev, 1);
206	if (err)
207		goto err_remove_notify;
208
209	return 0;
210
211err_remove_notify:
212	acpi_remove_notify_handler(handle, ACPI_DEVICE_NOTIFY, notify_handler);
213
214err_remove_input:
215	intel_hid_input_destroy(device);
216
217	return err;
218}
219
220static int intel_hid_remove(struct platform_device *device)
221{
222	acpi_handle handle = ACPI_HANDLE(&device->dev);
223
224	acpi_remove_notify_handler(handle, ACPI_DEVICE_NOTIFY, notify_handler);
225	intel_hid_input_destroy(device);
226	intel_hid_set_enable(&device->dev, 0);
227	acpi_remove_notify_handler(handle, ACPI_DEVICE_NOTIFY, notify_handler);
228
229	/*
230	 * Even if we failed to shut off the event stream, we can still
231	 * safely detach from the device.
232	 */
233	return 0;
234}
235
236static struct platform_driver intel_hid_pl_driver = {
237	.driver = {
238		.name = "intel-hid",
239		.acpi_match_table = intel_hid_ids,
240		.pm = &intel_hid_pl_pm_ops,
241	},
242	.probe = intel_hid_probe,
243	.remove = intel_hid_remove,
244};
245MODULE_DEVICE_TABLE(acpi, intel_hid_ids);
246
247/*
248 * Unfortunately, some laptops provide a _HID="INT33D5" device with
249 * _CID="PNP0C02".  This causes the pnpacpi scan driver to claim the
250 * ACPI node, so no platform device will be created.  The pnpacpi
251 * driver rejects this device in subsequent processing, so no physical
252 * node is created at all.
253 *
254 * As a workaround until the ACPI core figures out how to handle
255 * this corner case, manually ask the ACPI platform device code to
256 * claim the ACPI node.
257 */
258static acpi_status __init
259check_acpi_dev(acpi_handle handle, u32 lvl, void *context, void **rv)
260{
261	const struct acpi_device_id *ids = context;
262	struct acpi_device *dev;
263
264	if (acpi_bus_get_device(handle, &dev) != 0)
265		return AE_OK;
266
267	if (acpi_match_device_ids(dev, ids) == 0)
268		if (acpi_create_platform_device(dev))
269			dev_info(&dev->dev,
270				 "intel-hid: created platform device\n");
271
272	return AE_OK;
273}
274
275static int __init intel_hid_init(void)
276{
277	acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
278			    ACPI_UINT32_MAX, check_acpi_dev, NULL,
279			    (void *)intel_hid_ids, NULL);
280
281	return platform_driver_register(&intel_hid_pl_driver);
282}
283module_init(intel_hid_init);
284
285static void __exit intel_hid_exit(void)
286{
287	platform_driver_unregister(&intel_hid_pl_driver);
288}
289module_exit(intel_hid_exit);