+static int uclogic_input_mapping(struct hid_device *hdev, struct hid_input *hi,
+ struct hid_field *field, struct hid_usage *usage,
+ unsigned long **bit, int *max)
+{
+ struct uclogic_drvdata *drvdata = hid_get_drvdata(hdev);
+
+ /* discard the unused pen interface */
+ if ((drvdata->ignore_pen_usage) &&
+ (field->application == HID_DG_PEN))
+ return -1;
+
+ /* let hid-core decide what to do */
+ return 0;
+}
+
+static void uclogic_input_configured(struct hid_device *hdev,
+ struct hid_input *hi)
+{
+ char *name;
+ const char *suffix = NULL;
+ struct hid_field *field;
+ size_t len;
+
+ /* no report associated (HID_QUIRK_MULTI_INPUT not set) */
+ if (!hi->report)
+ return;
+
+ field = hi->report->field[0];
+
+ switch (field->application) {
+ case HID_GD_KEYBOARD:
+ suffix = "Keyboard";
+ break;
+ case HID_GD_MOUSE:
+ suffix = "Mouse";
+ break;
+ case HID_GD_KEYPAD:
+ suffix = "Pad";
+ break;
+ case HID_DG_PEN:
+ suffix = "Pen";
+ break;
+ case HID_CP_CONSUMER_CONTROL:
+ suffix = "Consumer Control";
+ break;
+ case HID_GD_SYSTEM_CONTROL:
+ suffix = "System Control";
+ break;
+ }
+
+ if (suffix) {
+ len = strlen(hdev->name) + 2 + strlen(suffix);
+ name = devm_kzalloc(&hi->input->dev, len, GFP_KERNEL);
+ if (name) {
+ snprintf(name, len, "%s %s", hdev->name, suffix);
+ hi->input->name = name;
+ }
+ }
+}
+
+/**
+ * Enable fully-functional tablet mode and determine device parameters.
+ *
+ * @hdev: HID device
+ */
+static int uclogic_tablet_enable(struct hid_device *hdev)
+{
+ int rc;
+ struct usb_device *usb_dev = hid_to_usb_dev(hdev);
+ struct uclogic_drvdata *drvdata = hid_get_drvdata(hdev);
+ __le16 *buf = NULL;
+ size_t len;
+ s32 params[UCLOGIC_PH_ID_NUM];
+ s32 resolution;
+ __u8 *p;
+ s32 v;
+
+ /*
+ * Read string descriptor containing tablet parameters. The specific
+ * string descriptor and data were discovered by sniffing the Windows
+ * driver traffic.
+ * NOTE: This enables fully-functional tablet mode.
+ */
+ len = UCLOGIC_PRM_NUM * sizeof(*buf);
+ buf = kmalloc(len, GFP_KERNEL);
+ if (buf == NULL) {
+ hid_err(hdev, "failed to allocate parameter buffer\n");
+ rc = -ENOMEM;
+ goto cleanup;
+ }
+ rc = usb_control_msg(usb_dev, usb_rcvctrlpipe(usb_dev, 0),
+ USB_REQ_GET_DESCRIPTOR, USB_DIR_IN,
+ (USB_DT_STRING << 8) + 0x64,
+ 0x0409, buf, len,
+ USB_CTRL_GET_TIMEOUT);
+ if (rc == -EPIPE) {
+ hid_err(hdev, "device parameters not found\n");
+ rc = -ENODEV;
+ goto cleanup;
+ } else if (rc < 0) {
+ hid_err(hdev, "failed to get device parameters: %d\n", rc);
+ rc = -ENODEV;
+ goto cleanup;
+ } else if (rc != len) {
+ hid_err(hdev, "invalid device parameters\n");
+ rc = -ENODEV;
+ goto cleanup;
+ }
+
+ /* Extract device parameters */
+ params[UCLOGIC_PH_ID_X_LM] = le16_to_cpu(buf[UCLOGIC_PRM_X_LM]);
+ params[UCLOGIC_PH_ID_Y_LM] = le16_to_cpu(buf[UCLOGIC_PRM_Y_LM]);
+ params[UCLOGIC_PH_ID_PRESSURE_LM] =
+ le16_to_cpu(buf[UCLOGIC_PRM_PRESSURE_LM]);
+ resolution = le16_to_cpu(buf[UCLOGIC_PRM_RESOLUTION]);
+ if (resolution == 0) {
+ params[UCLOGIC_PH_ID_X_PM] = 0;
+ params[UCLOGIC_PH_ID_Y_PM] = 0;
+ } else {
+ params[UCLOGIC_PH_ID_X_PM] = params[UCLOGIC_PH_ID_X_LM] *
+ 1000 / resolution;
+ params[UCLOGIC_PH_ID_Y_PM] = params[UCLOGIC_PH_ID_Y_LM] *
+ 1000 / resolution;
+ }
+
+ /* Allocate fixed report descriptor */
+ drvdata->rdesc = devm_kzalloc(&hdev->dev,
+ sizeof(uclogic_tablet_rdesc_template),
+ GFP_KERNEL);
+ if (drvdata->rdesc == NULL) {
+ hid_err(hdev, "failed to allocate fixed rdesc\n");
+ rc = -ENOMEM;
+ goto cleanup;
+ }
+ drvdata->rsize = sizeof(uclogic_tablet_rdesc_template);
+
+ /* Format fixed report descriptor */
+ memcpy(drvdata->rdesc, uclogic_tablet_rdesc_template,
+ drvdata->rsize);
+ for (p = drvdata->rdesc;
+ p <= drvdata->rdesc + drvdata->rsize - 4;) {
+ if (p[0] == 0xFE && p[1] == 0xED && p[2] == 0x1D &&
+ p[3] < sizeof(params)) {
+ v = params[p[3]];
+ put_unaligned(cpu_to_le32(v), (s32 *)p);
+ p += 4;
+ } else {
+ p++;
+ }
+ }
+
+ rc = 0;
+
+cleanup:
+ kfree(buf);
+ return rc;
+}
+
+static int uclogic_probe(struct hid_device *hdev,
+ const struct hid_device_id *id)
+{
+ int rc;
+ struct usb_interface *intf = to_usb_interface(hdev->dev.parent);
+ struct uclogic_drvdata *drvdata;
+
+ /*
+ * libinput requires the pad interface to be on a different node
+ * than the pen, so use QUIRK_MULTI_INPUT for all tablets.
+ */
+ hdev->quirks |= HID_QUIRK_MULTI_INPUT;
+ hdev->quirks |= HID_QUIRK_NO_EMPTY_INPUT;
+
+ /* Allocate and assign driver data */
+ drvdata = devm_kzalloc(&hdev->dev, sizeof(*drvdata), GFP_KERNEL);
+ if (drvdata == NULL)
+ return -ENOMEM;
+
+ hid_set_drvdata(hdev, drvdata);
+
+ switch (id->product) {
+ case USB_DEVICE_ID_HUION_TABLET:
+ /* If this is the pen interface */
+ if (intf->cur_altsetting->desc.bInterfaceNumber == 0) {
+ rc = uclogic_tablet_enable(hdev);
+ if (rc) {
+ hid_err(hdev, "tablet enabling failed\n");
+ return rc;
+ }
+ drvdata->invert_pen_inrange = true;
+ } else {
+ drvdata->ignore_pen_usage = true;
+ }
+ break;
+ }
+
+ rc = hid_parse(hdev);
+ if (rc) {
+ hid_err(hdev, "parse failed\n");
+ return rc;
+ }
+
+ rc = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
+ if (rc) {
+ hid_err(hdev, "hw start failed\n");
+ return rc;
+ }
+
+ return 0;
+}
+
+static int uclogic_raw_event(struct hid_device *hdev, struct hid_report *report,
+ u8 *data, int size)
+{
+ struct uclogic_drvdata *drvdata = hid_get_drvdata(hdev);
+
+ if ((drvdata->invert_pen_inrange) &&
+ (report->type == HID_INPUT_REPORT) &&
+ (report->id == UCLOGIC_PEN_REPORT_ID) &&
+ (size >= 2))
+ /* Invert the in-range bit */
+ data[1] ^= 0x40;
+
+ return 0;
+}
+