1 /*
2  * HID over I2C ACPI Subclass
3  *
4  * Copyright (c) 2012 Benjamin Tissoires <benjamin.tissoires@gmail.com>
5  * Copyright (c) 2012 Ecole Nationale de l'Aviation Civile, France
6  * Copyright (c) 2012 Red Hat, Inc
7  *
8  * This code was forked out of the core code, which was partly based on
9  * "USB HID support for Linux":
10  *
11  *  Copyright (c) 1999 Andreas Gal
12  *  Copyright (c) 2000-2005 Vojtech Pavlik <vojtech@suse.cz>
13  *  Copyright (c) 2005 Michael Haboustak <mike-@cinci.rr.com> for Concept2, Inc
14  *  Copyright (c) 2007-2008 Oliver Neukum
15  *  Copyright (c) 2006-2010 Jiri Kosina
16  *
17  * This file is subject to the terms and conditions of the GNU General Public
18  * License.  See the file COPYING in the main directory of this archive for
19  * more details.
20  */
21 
22 #include <linux/acpi.h>
23 #include <linux/device.h>
24 #include <linux/i2c.h>
25 #include <linux/kernel.h>
26 #include <linux/module.h>
27 #include <linux/pm.h>
28 #include <linux/uuid.h>
29 
30 #include "i2c-hid.h"
31 
32 struct i2c_hid_acpi {
33 	struct i2chid_ops ops;
34 	struct acpi_device *adev;
35 };
36 
37 static const struct acpi_device_id i2c_hid_acpi_blacklist[] = {
38 	/*
39 	 * The CHPN0001 ACPI device, which is used to describe the Chipone
40 	 * ICN8505 controller, has a _CID of PNP0C50 but is not HID compatible.
41 	 */
42 	{ "CHPN0001" },
43 	{ }
44 };
45 
46 /* HID I²C Device: 3cdff6f7-4267-4555-ad05-b30a3d8938de */
47 static guid_t i2c_hid_guid =
48 	GUID_INIT(0x3CDFF6F7, 0x4267, 0x4555,
49 		  0xAD, 0x05, 0xB3, 0x0A, 0x3D, 0x89, 0x38, 0xDE);
50 
51 static int i2c_hid_acpi_get_descriptor(struct i2c_hid_acpi *ihid_acpi)
52 {
53 	struct acpi_device *adev = ihid_acpi->adev;
54 	acpi_handle handle = acpi_device_handle(adev);
55 	union acpi_object *obj;
56 	u16 hid_descriptor_address;
57 
58 	if (acpi_match_device_ids(adev, i2c_hid_acpi_blacklist) == 0)
59 		return -ENODEV;
60 
61 	obj = acpi_evaluate_dsm_typed(handle, &i2c_hid_guid, 1, 1, NULL,
62 				      ACPI_TYPE_INTEGER);
63 	if (!obj) {
64 		acpi_handle_err(handle, "Error _DSM call to get HID descriptor address failed\n");
65 		return -ENODEV;
66 	}
67 
68 	hid_descriptor_address = obj->integer.value;
69 	ACPI_FREE(obj);
70 
71 	return hid_descriptor_address;
72 }
73 
74 static void i2c_hid_acpi_shutdown_tail(struct i2chid_ops *ops)
75 {
76 	struct i2c_hid_acpi *ihid_acpi = container_of(ops, struct i2c_hid_acpi, ops);
77 
78 	acpi_device_set_power(ihid_acpi->adev, ACPI_STATE_D3_COLD);
79 }
80 
81 static int i2c_hid_acpi_probe(struct i2c_client *client)
82 {
83 	struct device *dev = &client->dev;
84 	struct i2c_hid_acpi *ihid_acpi;
85 	u16 hid_descriptor_address;
86 	int ret;
87 
88 	ihid_acpi = devm_kzalloc(&client->dev, sizeof(*ihid_acpi), GFP_KERNEL);
89 	if (!ihid_acpi)
90 		return -ENOMEM;
91 
92 	ihid_acpi->adev = ACPI_COMPANION(dev);
93 	ihid_acpi->ops.shutdown_tail = i2c_hid_acpi_shutdown_tail;
94 
95 	ret = i2c_hid_acpi_get_descriptor(ihid_acpi);
96 	if (ret < 0)
97 		return ret;
98 	hid_descriptor_address = ret;
99 
100 	acpi_device_fix_up_power(ihid_acpi->adev);
101 
102 	return i2c_hid_core_probe(client, &ihid_acpi->ops,
103 				  hid_descriptor_address, 0);
104 }
105 
106 static const struct acpi_device_id i2c_hid_acpi_match[] = {
107 	{ "ACPI0C50" },
108 	{ "PNP0C50" },
109 	{ }
110 };
111 MODULE_DEVICE_TABLE(acpi, i2c_hid_acpi_match);
112 
113 static struct i2c_driver i2c_hid_acpi_driver = {
114 	.driver = {
115 		.name	= "i2c_hid_acpi",
116 		.pm	= &i2c_hid_core_pm,
117 		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
118 		.acpi_match_table = i2c_hid_acpi_match,
119 	},
120 
121 	.probe		= i2c_hid_acpi_probe,
122 	.remove		= i2c_hid_core_remove,
123 	.shutdown	= i2c_hid_core_shutdown,
124 };
125 
126 module_i2c_driver(i2c_hid_acpi_driver);
127 
128 MODULE_DESCRIPTION("HID over I2C ACPI driver");
129 MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@gmail.com>");
130 MODULE_LICENSE("GPL");
131