summaryrefslogtreecommitdiff
path: root/drivers/hid/hid-vivaldi-common.c
blob: bf734055d4b69ddebd39a0c3c933872b75e0fa7a (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
// SPDX-License-Identifier: GPL-2.0
/*
 * Helpers for ChromeOS HID Vivaldi keyboards
 *
 * Copyright (C) 2022 Google, Inc
 */

#include <linux/export.h>
#include <linux/hid.h>
#include <linux/input/vivaldi-fmap.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/types.h>

#include "hid-vivaldi-common.h"

#define MIN_FN_ROW_KEY 1
#define MAX_FN_ROW_KEY VIVALDI_MAX_FUNCTION_ROW_KEYS
#define HID_VD_FN_ROW_PHYSMAP 0x00000001
#define HID_USAGE_FN_ROW_PHYSMAP (HID_UP_GOOGLEVENDOR | HID_VD_FN_ROW_PHYSMAP)

/**
 * vivaldi_feature_mapping - Fill out vivaldi keymap data exposed via HID
 * @hdev: HID device to parse
 * @field: HID field to parse
 * @usage: HID usage to parse
 *
 * Note: this function assumes that driver data attached to @hdev contains an
 * instance of &struct vivaldi_data at the very beginning.
 */
void vivaldi_feature_mapping(struct hid_device *hdev,
			     struct hid_field *field, struct hid_usage *usage)
{
	struct vivaldi_data *data = hid_get_drvdata(hdev);
	struct hid_report *report = field->report;
	u8 *report_data, *buf;
	u32 report_len;
	unsigned int fn_key;
	int ret;

	if (field->logical != HID_USAGE_FN_ROW_PHYSMAP ||
	    (usage->hid & HID_USAGE_PAGE) != HID_UP_ORDINAL)
		return;

	fn_key = usage->hid & HID_USAGE;
	if (fn_key < MIN_FN_ROW_KEY || fn_key > MAX_FN_ROW_KEY)
		return;

	if (fn_key > data->num_function_row_keys)
		data->num_function_row_keys = fn_key;

	report_data = buf = hid_alloc_report_buf(report, GFP_KERNEL);
	if (!report_data)
		return;

	report_len = hid_report_len(report);
	if (!report->id) {
		/*
		 * hid_hw_raw_request() will stuff report ID (which will be 0)
		 * into the first byte of the buffer even for unnumbered
		 * reports, so we need to account for this to avoid getting
		 * -EOVERFLOW in return.
		 * Note that hid_alloc_report_buf() adds 7 bytes to the size
		 * so we can safely say that we have space for an extra byte.
		 */
		report_len++;
	}

	ret = hid_hw_raw_request(hdev, report->id, report_data,
				 report_len, HID_FEATURE_REPORT,
				 HID_REQ_GET_REPORT);
	if (ret < 0) {
		dev_warn(&hdev->dev, "failed to fetch feature %d\n",
			 field->report->id);
		goto out;
	}

	if (!report->id) {
		/*
		 * Undo the damage from hid_hw_raw_request() for unnumbered
		 * reports.
		 */
		report_data++;
		report_len--;
	}

	ret = hid_report_raw_event(hdev, HID_FEATURE_REPORT, report_data,
				   report_len, 0);
	if (ret) {
		dev_warn(&hdev->dev, "failed to report feature %d\n",
			 field->report->id);
		goto out;
	}

	data->function_row_physmap[fn_key - MIN_FN_ROW_KEY] =
		field->value[usage->usage_index];

out:
	kfree(buf);
}
EXPORT_SYMBOL_GPL(vivaldi_feature_mapping);

static ssize_t function_row_physmap_show(struct device *dev,
					 struct device_attribute *attr,
					 char *buf)
{
	struct hid_device *hdev = to_hid_device(dev);
	struct vivaldi_data *data = hid_get_drvdata(hdev);

	return vivaldi_function_row_physmap_show(data, buf);
}

static DEVICE_ATTR_RO(function_row_physmap);
static struct attribute *vivaldi_sysfs_attrs[] = {
	&dev_attr_function_row_physmap.attr,
	NULL
};

static umode_t vivaldi_is_visible(struct kobject *kobj, struct attribute *attr,
				  int n)
{
	struct hid_device *hdev = to_hid_device(kobj_to_dev(kobj));
	struct vivaldi_data *data = hid_get_drvdata(hdev);

	if (!data->num_function_row_keys)
		return 0;
	return attr->mode;
}

static const struct attribute_group vivaldi_attribute_group = {
	.attrs = vivaldi_sysfs_attrs,
	.is_visible = vivaldi_is_visible,
};

const struct attribute_group *vivaldi_attribute_groups[] = {
	&vivaldi_attribute_group,
	NULL,
};
EXPORT_SYMBOL_GPL(vivaldi_attribute_groups);

MODULE_DESCRIPTION("Helpers for ChromeOS HID Vivaldi keyboards");
MODULE_LICENSE("GPL");