drivers/hid/hid-vivaldi.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * HID support for Vivaldi Keyboard
   4  *
   5  * Copyright 2020 Google LLC.
   6  * Author: Sean O'Brien <seobrien@chromium.org>
   7  */
   8
   9 #include <linux/hid.h>
  10 #include <linux/module.h>
  11
  12 #define MIN_FN_ROW_KEY  1
  13 #define MAX_FN_ROW_KEY  24
  14 #define HID_VD_FN_ROW_PHYSMAP 0x00000001
  15 #define HID_USAGE_FN_ROW_PHYSMAP (HID_UP_GOOGLEVENDOR | HID_VD_FN_ROW_PHYSMAP)
  16
  17 static struct hid_driver hid_vivaldi;
  18
  19 struct vivaldi_data {
  20         u32 function_row_physmap[MAX_FN_ROW_KEY - MIN_FN_ROW_KEY + 1];
  21         int max_function_row_key;
  22 };
  23
  24 static ssize_t function_row_physmap_show(struct device *dev,
  25                                          struct device_attribute *attr,
  26                                          char *buf)
  27 {
  28         struct hid_device *hdev = to_hid_device(dev);
  29         struct vivaldi_data *drvdata = hid_get_drvdata(hdev);
  30         ssize_t size = 0;
  31         int i;
  32
  33         if (!drvdata->max_function_row_key)
  34                 return 0;
  35
  36         for (i = 0; i < drvdata->max_function_row_key; i++)
  37                 size += sprintf(buf + size, "%02X ",
  38                                 drvdata->function_row_physmap[i]);
  39         size += sprintf(buf + size, "\n");
  40         return size;
  41 }
  42
  43 DEVICE_ATTR_RO(function_row_physmap);
  44 static struct attribute *sysfs_attrs[] = {
  45         &dev_attr_function_row_physmap.attr,
  46         NULL
  47 };
  48
  49 static const struct attribute_group input_attribute_group = {
  50         .attrs = sysfs_attrs
  51 };
  52
  53 static int vivaldi_probe(struct hid_device *hdev,
  54                          const struct hid_device_id *id)
  55 {
  56         struct vivaldi_data *drvdata;
  57         int ret;
  58
  59         drvdata = devm_kzalloc(&hdev->dev, sizeof(*drvdata), GFP_KERNEL);
  60         hid_set_drvdata(hdev, drvdata);
  61
  62         ret = hid_parse(hdev);
  63         if (ret)
  64                 return ret;
  65
  66         return hid_hw_start(hdev, HID_CONNECT_DEFAULT);
  67 }
  68
  69 static void vivaldi_feature_mapping(struct hid_device *hdev,
  70                                     struct hid_field *field,
  71                                     struct hid_usage *usage)
  72 {
  73         struct vivaldi_data *drvdata = hid_get_drvdata(hdev);
  74         int fn_key;
  75         int ret;
  76         u32 report_len;
  77         u8 *buf;
  78
  79         if (field->logical != HID_USAGE_FN_ROW_PHYSMAP ||
  80             (usage->hid & HID_USAGE_PAGE) != HID_UP_ORDINAL)
  81                 return;
  82
  83         fn_key = (usage->hid & HID_USAGE);
  84         if (fn_key < MIN_FN_ROW_KEY || fn_key > MAX_FN_ROW_KEY)
  85                 return;
  86         if (fn_key > drvdata->max_function_row_key)
  87                 drvdata->max_function_row_key = fn_key;
  88
  89         buf = hid_alloc_report_buf(field->report, GFP_KERNEL);
  90         if (!buf)
  91                 return;
  92
  93         report_len = hid_report_len(field->report);
  94         ret = hid_hw_raw_request(hdev, field->report->id, buf,
  95                                  report_len, HID_FEATURE_REPORT,
  96                                  HID_REQ_GET_REPORT);
  97         if (ret < 0) {
  98                 dev_warn(&hdev->dev, "failed to fetch feature %d\n",
  99                          field->report->id);
 100                 goto out;
 101         }
 102
 103         ret = hid_report_raw_event(hdev, HID_FEATURE_REPORT, buf,
 104                                    report_len, 0);
 105         if (ret) {
 106                 dev_warn(&hdev->dev, "failed to report feature %d\n",
 107                          field->report->id);
 108                 goto out;
 109         }
 110
 111         drvdata->function_row_physmap[fn_key - MIN_FN_ROW_KEY] =
 112             field->value[usage->usage_index];
 113
 114 out:
 115         kfree(buf);
 116 }
 117
 118 static int vivaldi_input_configured(struct hid_device *hdev,
 119                                     struct hid_input *hidinput)
 120 {
 121         return sysfs_create_group(&hdev->dev.kobj, &input_attribute_group);
 122 }
 123
 124 static const struct hid_device_id vivaldi_table[] = {
 125         { HID_DEVICE(HID_BUS_ANY, HID_GROUP_VIVALDI, HID_ANY_ID,
 126                      HID_ANY_ID) },
 127         { }
 128 };
 129
 130 MODULE_DEVICE_TABLE(hid, vivaldi_table);
 131
 132 static struct hid_driver hid_vivaldi = {
 133         .name = "hid-vivaldi",
 134         .id_table = vivaldi_table,
 135         .probe = vivaldi_probe,
 136         .feature_mapping = vivaldi_feature_mapping,
 137         .input_configured = vivaldi_input_configured,
 138 };
 139
 140 module_hid_driver(hid_vivaldi);
 141
 142 MODULE_AUTHOR("Sean O'Brien");
 143 MODULE_DESCRIPTION("HID vivaldi driver");
 144 MODULE_LICENSE("GPL");