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", 0 },
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 acpi_device *adev)
52 {
53 	acpi_handle handle = acpi_device_handle(adev);
54 	union acpi_object *obj;
55 	u16 hid_descriptor_address;
56 
57 	if (acpi_match_device_ids(adev, i2c_hid_acpi_blacklist) == 0)
58 		return -ENODEV;
59 
60 	obj = acpi_evaluate_dsm_typed(handle, &i2c_hid_guid, 1, 1, NULL,
61 				      ACPI_TYPE_INTEGER);
62 	if (!obj) {
63 		acpi_handle_err(handle, "Error _DSM call to get HID descriptor address failed\n");
64 		return -ENODEV;
65 	}
66 
67 	hid_descriptor_address = obj->integer.value;
68 	ACPI_FREE(obj);
69 
70 	return hid_descriptor_address;
71 }
72 
73 static void i2c_hid_acpi_shutdown_tail(struct i2chid_ops *ops)
74 {
75 	struct i2c_hid_acpi *ihid_acpi = container_of(ops, struct i2c_hid_acpi, ops);
76 
77 	acpi_device_set_power(ihid_acpi->adev, ACPI_STATE_D3_COLD);
78 }
79 
80 static int i2c_hid_acpi_probe(struct i2c_client *client)
81 {
82 	struct device *dev = &client->dev;
83 	struct i2c_hid_acpi *ihid_acpi;
84 	struct acpi_device *adev;
85 	u16 hid_descriptor_address;
86 	int ret;
87 
88 	adev = ACPI_COMPANION(dev);
89 	if (!adev) {
90 		dev_err(&client->dev, "Error could not get ACPI device\n");
91 		return -ENODEV;
92 	}
93 
94 	ihid_acpi = devm_kzalloc(&client->dev, sizeof(*ihid_acpi), GFP_KERNEL);
95 	if (!ihid_acpi)
96 		return -ENOMEM;
97 
98 	ihid_acpi->adev = adev;
99 	ihid_acpi->ops.shutdown_tail = i2c_hid_acpi_shutdown_tail;
100 
101 	ret = i2c_hid_acpi_get_descriptor(adev);
102 	if (ret < 0)
103 		return ret;
104 	hid_descriptor_address = ret;
105 
106 	acpi_device_fix_up_power(adev);
107 
108 	return i2c_hid_core_probe(client, &ihid_acpi->ops,
109 				  hid_descriptor_address, 0);
110 }
111 
112 static const struct acpi_device_id i2c_hid_acpi_match[] = {
113 	{"ACPI0C50", 0 },
114 	{"PNP0C50", 0 },
115 	{ },
116 };
117 MODULE_DEVICE_TABLE(acpi, i2c_hid_acpi_match);
118 
119 static struct i2c_driver i2c_hid_acpi_driver = {
120 	.driver = {
121 		.name	= "i2c_hid_acpi",
122 		.pm	= &i2c_hid_core_pm,
123 		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
124 		.acpi_match_table = i2c_hid_acpi_match,
125 	},
126 
127 	.probe_new	= i2c_hid_acpi_probe,
128 	.remove		= i2c_hid_core_remove,
129 	.shutdown	= i2c_hid_core_shutdown,
130 };
131 
132 module_i2c_driver(i2c_hid_acpi_driver);
133 
134 MODULE_DESCRIPTION("HID over I2C ACPI driver");
135 MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@gmail.com>");
136 MODULE_LICENSE("GPL");
137