--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * HID support for Vivaldi Keyboard
+ *
+ * Copyright 2020 Google LLC.
+ * Author: Sean O'Brien <seobrien@chromium.org>
+ */
+
+#include <linux/hid.h>
+#include <linux/module.h>
+
+#define MIN_FN_ROW_KEY 1
+#define MAX_FN_ROW_KEY 24
+#define HID_VD_FN_ROW_PHYSMAP 0x00000001
+#define HID_USAGE_FN_ROW_PHYSMAP (HID_UP_GOOGLEVENDOR | HID_VD_FN_ROW_PHYSMAP)
+
+static struct hid_driver hid_vivaldi;
+
+struct vivaldi_data {
+ u32 function_row_physmap[MAX_FN_ROW_KEY - MIN_FN_ROW_KEY + 1];
+ int max_function_row_key;
+};
+
+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 *drvdata = hid_get_drvdata(hdev);
+ ssize_t size = 0;
+ int i;
+
+ if (!drvdata->max_function_row_key)
+ return 0;
+
+ for (i = 0; i < drvdata->max_function_row_key; i++)
+ size += sprintf(buf + size, "%02X ",
+ drvdata->function_row_physmap[i]);
+ size += sprintf(buf + size, "\n");
+ return size;
+}
+
+DEVICE_ATTR_RO(function_row_physmap);
+static struct attribute *sysfs_attrs[] = {
+ &dev_attr_function_row_physmap.attr,
+ NULL
+};
+
+static const struct attribute_group input_attribute_group = {
+ .attrs = sysfs_attrs
+};
+
+static int vivaldi_probe(struct hid_device *hdev,
+ const struct hid_device_id *id)
+{
+ struct vivaldi_data *drvdata;
+ int ret;
+
+ drvdata = devm_kzalloc(&hdev->dev, sizeof(*drvdata), GFP_KERNEL);
+ hid_set_drvdata(hdev, drvdata);
+
+ ret = hid_parse(hdev);
+ if (ret)
+ return ret;
+
+ return hid_hw_start(hdev, HID_CONNECT_DEFAULT);
+}
+
+static void vivaldi_feature_mapping(struct hid_device *hdev,
+ struct hid_field *field,
+ struct hid_usage *usage)
+{
+ struct vivaldi_data *drvdata = hid_get_drvdata(hdev);
+ int fn_key;
+ int ret;
+ u32 report_len;
+ u8 *buf;
+
+ 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 > drvdata->max_function_row_key)
+ drvdata->max_function_row_key = fn_key;
+
+ buf = hid_alloc_report_buf(field->report, GFP_KERNEL);
+ if (!buf)
+ return;
+
+ report_len = hid_report_len(field->report);
+ ret = hid_hw_raw_request(hdev, field->report->id, buf,
+ 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;
+ }
+
+ ret = hid_report_raw_event(hdev, HID_FEATURE_REPORT, buf,
+ report_len, 0);
+ if (ret) {
+ dev_warn(&hdev->dev, "failed to report feature %d\n",
+ field->report->id);
+ goto out;
+ }
+
+ drvdata->function_row_physmap[fn_key - MIN_FN_ROW_KEY] =
+ field->value[usage->usage_index];
+
+out:
+ kfree(buf);
+}
+
+static int vivaldi_input_configured(struct hid_device *hdev,
+ struct hid_input *hidinput)
+{
+ return sysfs_create_group(&hdev->dev.kobj, &input_attribute_group);
+}
+
+static const struct hid_device_id vivaldi_table[] = {
+ { HID_DEVICE(HID_BUS_ANY, HID_GROUP_VIVALDI, HID_ANY_ID,
+ HID_ANY_ID) },
+ { }
+};
+
+MODULE_DEVICE_TABLE(hid, vivaldi_table);
+
+static struct hid_driver hid_vivaldi = {
+ .name = "hid-vivaldi",
+ .id_table = vivaldi_table,
+ .probe = vivaldi_probe,
+ .feature_mapping = vivaldi_feature_mapping,
+ .input_configured = vivaldi_input_configured,
+};
+
+module_hid_driver(hid_vivaldi);
+
+MODULE_AUTHOR("Sean O'Brien");
+MODULE_DESCRIPTION("HID vivaldi driver");
+MODULE_LICENSE("GPL");