From b7eeae7b0d3b1fc034b95ae3cc86c413b6b2efb2 Mon Sep 17 00:00:00 2001
From: Kai Krakow <kai@kaishome.de>
Date: Sun, 28 Mar 2021 16:05:52 +0200
Subject: [PATCH] xpadneo, devices: Add support for synthetic devices

In preparation for mouse mode and keyboard emulation, we need to be
able to create virtual devices associated with the controller.

Signed-off-by: Kai Krakow <kai@kaishome.de>
---
 hid-xpadneo/src/hid-xpadneo.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/hid-xpadneo/src/hid-xpadneo.c b/hid-xpadneo/src/hid-xpadneo.c
index 509768de..c933992f 100644
--- a/hid-xpadneo/src/hid-xpadneo.c
+++ b/hid-xpadneo/src/hid-xpadneo.c
@@ -1224,6 +1224,36 @@ static int xpadneo_init_hw(struct hid_device *hdev)
 	return ret;
 }
 
+static int xpadneo_init_synthetic(struct xpadneo_devdata *xdata, char *suffix,
+				  struct input_dev **devp)
+{
+	struct hid_device *hdev = xdata->hdev;
+	struct input_dev *input_dev = devm_input_allocate_device(&hdev->dev);
+	size_t suffix_len, name_len;
+
+	if (!input_dev)
+		return -ENOMEM;
+
+	name_len = strlen(hdev->name);
+	suffix_len = strlen(suffix);
+	if ((name_len < suffix_len) || strcmp(xdata->hdev->name + name_len - suffix_len, suffix)) {
+		input_dev->name = kasprintf(GFP_KERNEL, "%s %s", hdev->name, suffix);
+		if (!input_dev->name)
+			return -ENOMEM;
+	}
+
+	dev_set_drvdata(&input_dev->dev, xdata);
+	input_dev->phys = hdev->phys;
+	input_dev->uniq = hdev->uniq;
+	input_dev->id.bustype = hdev->bus;
+	input_dev->id.vendor = hdev->vendor;
+	input_dev->id.product = hdev->product;
+	input_dev->id.version = hdev->version;
+
+	*devp = input_dev;
+	return 0;
+}
+
 static int xpadneo_probe(struct hid_device *hdev, const struct hid_device_id *id)
 {
 	int ret;