HID: hid-logitech-hidpp: Add basic support for Logitech G920

This patch adds basic support for the Logitech G920 wheel when in HID
mode. This wheel 'speaks' the HID++ protocol, and therefor is driven
with hid-logitech-hidpp.

At this stage the driver only shows that it can communicate with the
wheel by outputting the name discovered over HID++.

The normal HID functions work to give input functionality using
joystick/event interface.

Note: in 'hidpp_probe()' we have to start the hardware to get packets
flowing, the same might apply in future for other devices which don't
use the unifying protocol.

Signed-off-by: Simon Wood <simon@mungewell.org>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-hidpp.c
index 0f53dc8..98b8f09 100644
--- a/drivers/hid/hid-logitech-hidpp.c
+++ b/drivers/hid/hid-logitech-hidpp.c
@@ -49,11 +49,13 @@
 #define HIDPP_QUIRK_CLASS_WTP			BIT(0)
 #define HIDPP_QUIRK_CLASS_M560			BIT(1)
 #define HIDPP_QUIRK_CLASS_K400			BIT(2)
+#define HIDPP_QUIRK_CLASS_G920			BIT(3)
 
 /* bits 2..20 are reserved for classes */
 #define HIDPP_QUIRK_CONNECT_EVENTS		BIT(21)
 #define HIDPP_QUIRK_WTP_PHYSICAL_BUTTONS	BIT(22)
 #define HIDPP_QUIRK_NO_HIDINPUT			BIT(23)
+#define HIDPP_QUIRK_FORCE_OUTPUT_REPORTS	BIT(24)
 
 #define HIDPP_QUIRK_DELAYED_INIT		(HIDPP_QUIRK_NO_HIDINPUT | \
 						 HIDPP_QUIRK_CONNECT_EVENTS)
@@ -146,8 +148,11 @@
 static int __hidpp_send_report(struct hid_device *hdev,
 				struct hidpp_report *hidpp_report)
 {
+	struct hidpp_device *hidpp = hid_get_drvdata(hdev);
 	int fields_count, ret;
 
+	hidpp = hid_get_drvdata(hdev);
+
 	switch (hidpp_report->report_id) {
 	case REPORT_ID_HIDPP_SHORT:
 		fields_count = HIDPP_REPORT_SHORT_LENGTH;
@@ -168,9 +173,13 @@
 	 */
 	hidpp_report->device_index = 0xff;
 
-	ret = hid_hw_raw_request(hdev, hidpp_report->report_id,
-		(u8 *)hidpp_report, fields_count, HID_OUTPUT_REPORT,
-		HID_REQ_SET_REPORT);
+	if (hidpp->quirks & HIDPP_QUIRK_FORCE_OUTPUT_REPORTS) {
+		ret = hid_hw_output_report(hdev, (u8 *)hidpp_report, fields_count);
+	} else {
+		ret = hid_hw_raw_request(hdev, hidpp_report->report_id,
+			(u8 *)hidpp_report, fields_count, HID_OUTPUT_REPORT,
+			HID_REQ_SET_REPORT);
+	}
 
 	return ret == fields_count ? 0 : -1;
 }
@@ -1430,10 +1439,12 @@
 	else
 		name = hidpp_get_device_name(hidpp);
 
-	if (!name)
+	if (!name) {
 		hid_err(hdev, "unable to retrieve the name of the device");
-	else
+	} else {
+		dbg_hid("HID++: Got name: %s\n", name);
 		snprintf(hdev->name, sizeof(hdev->name), "%s", name);
+	}
 
 	kfree(name);
 }
@@ -1596,6 +1607,25 @@
 		goto hid_parse_fail;
 	}
 
+	if (hidpp->quirks & HIDPP_QUIRK_NO_HIDINPUT)
+		connect_mask &= ~HID_CONNECT_HIDINPUT;
+
+	if (hidpp->quirks & HIDPP_QUIRK_CLASS_G920) {
+		ret = hid_hw_start(hdev, connect_mask);
+		if (ret) {
+			hid_err(hdev, "hw start failed\n");
+			goto hid_hw_start_fail;
+		}
+		ret = hid_hw_open(hdev);
+		if (ret < 0) {
+			dev_err(&hdev->dev, "%s:hid_hw_open returned error:%d\n",
+				__func__, ret);
+			hid_hw_stop(hdev);
+			goto hid_hw_start_fail;
+		}
+	}
+
+
 	/* Allow incoming packets */
 	hid_device_io_start(hdev);
 
@@ -1604,8 +1634,7 @@
 		if (!connected) {
 			ret = -ENODEV;
 			hid_err(hdev, "Device not connected");
-			hid_device_io_stop(hdev);
-			goto hid_parse_fail;
+			goto hid_hw_open_failed;
 		}
 
 		hid_info(hdev, "HID++ %u.%u device connected.\n",
@@ -1618,19 +1647,18 @@
 	if (connected && (hidpp->quirks & HIDPP_QUIRK_CLASS_WTP)) {
 		ret = wtp_get_config(hidpp);
 		if (ret)
-			goto hid_parse_fail;
+			goto hid_hw_open_failed;
 	}
 
 	/* Block incoming packets */
 	hid_device_io_stop(hdev);
 
-	if (hidpp->quirks & HIDPP_QUIRK_NO_HIDINPUT)
-		connect_mask &= ~HID_CONNECT_HIDINPUT;
-
-	ret = hid_hw_start(hdev, connect_mask);
-	if (ret) {
-		hid_err(hdev, "%s:hid_hw_start returned error\n", __func__);
-		goto hid_hw_start_fail;
+	if (!(hidpp->quirks & HIDPP_QUIRK_CLASS_G920)) {
+		ret = hid_hw_start(hdev, connect_mask);
+		if (ret) {
+			hid_err(hdev, "%s:hid_hw_start returned error\n", __func__);
+			goto hid_hw_start_fail;
+		}
 	}
 
 	if (hidpp->quirks & HIDPP_QUIRK_CONNECT_EVENTS) {
@@ -1642,6 +1670,12 @@
 
 	return ret;
 
+hid_hw_open_failed:
+	hid_device_io_stop(hdev);
+	if (hidpp->quirks & HIDPP_QUIRK_CLASS_G920) {
+		hid_hw_close(hdev);
+		hid_hw_stop(hdev);
+	}
 hid_hw_start_fail:
 hid_parse_fail:
 	cancel_work_sync(&hidpp->work);
@@ -1655,9 +1689,11 @@
 {
 	struct hidpp_device *hidpp = hid_get_drvdata(hdev);
 
+	if (hidpp->quirks & HIDPP_QUIRK_CLASS_G920)
+		hid_hw_close(hdev);
+	hid_hw_stop(hdev);
 	cancel_work_sync(&hidpp->work);
 	mutex_destroy(&hidpp->send_mutex);
-	hid_hw_stop(hdev);
 }
 
 static const struct hid_device_id hidpp_devices[] = {
@@ -1685,6 +1721,9 @@
 
 	{ HID_DEVICE(BUS_USB, HID_GROUP_LOGITECH_DJ_DEVICE,
 		USB_VENDOR_ID_LOGITECH, HID_ANY_ID)},
+
+	{ HID_USB_DEVICE(USB_VENDOR_ID_LOGITECH, USB_DEVICE_ID_LOGITECH_G920_WHEEL),
+		.driver_data = HIDPP_QUIRK_CLASS_G920 | HIDPP_QUIRK_FORCE_OUTPUT_REPORTS},
 	{}
 };