HID: Add driver for VRC-2 Car Controller

VRC-2 is 2-axis controller often used in car simulators.
Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Link: https://lore.kernel.org/r/20220902082552.2433744-2-marcus.folkesson@gmail.com

MAINTAINERS

@@ -9065,6 +9065,12 @@ F:	drivers/hid/hid-sensor-*
 F:	drivers/iio/*/hid-*
 F:	include/linux/hid-sensor-*
 
+HID VRC-2 CAR CONTROLLER DRIVER
+M:	Marcus Folkesson <marcus.folkesson@gmail.com>
+L:	linux-input@vger.kernel.org
+S:	Maintained
+F:	drivers/hid/hid-vrc2.c
+
 HID WACOM DRIVER
 M:	Ping Cheng <ping.cheng@wacom.com>
 M:	Jason Gerecke  <jason.gerecke@wacom.com>

drivers/hid/Kconfig

@@ -481,6 +481,16 @@ config HID_VIEWSONIC
 	help
 	  Support for ViewSonic/Signotec PD1011 signature pad.
 
+config HID_VRC2
+	tristate "VRC-2 Car Controller"
+	depends on HID
+	help
+        Support for VRC-2 which is a 2-axis controller often used in
+        car simulators.
+
+        To compile this driver as a module, choose M here: the
+        module will be called hid-vrc2.
+
 config HID_XIAOMI
 	tristate "Xiaomi"
 	depends on HID

drivers/hid/Makefile

@@ -136,6 +136,7 @@ obj-$(CONFIG_HID_XINMO)		+= hid-xinmo.o
 obj-$(CONFIG_HID_ZEROPLUS)	+= hid-zpff.o
 obj-$(CONFIG_HID_ZYDACRON)	+= hid-zydacron.o
 obj-$(CONFIG_HID_VIEWSONIC)	+= hid-viewsonic.o
+obj-$(CONFIG_HID_VRC2)		+= hid-vrc2.o
 
 wacom-objs			:= wacom_wac.o wacom_sys.o
 obj-$(CONFIG_HID_WACOM)		+= wacom.o

drivers/hid/hid-vrc2.c

+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * HID driver for VRC-2 2-axis Car controller
+ *
+ * Copyright (C) 2022 Marcus Folkesson <marcus.folkesson@gmail.com>
+ */
+
+#include <linux/device.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+
+/*
+ * VID/PID are probably "borrowed", so keep them locally and
+ * do not populate hid-ids.h with those.
+ */
+#define USB_VENDOR_ID_VRC2	(0x07c0)
+#define USB_DEVICE_ID_VRC2	(0x1125)
+
+static __u8 vrc2_rdesc_fixed[] = {
+	0x05, 0x01,        // Usage Page (Generic Desktop Ctrls)
+	0x09, 0x04,        // Usage (Joystick)
+	0xA1, 0x01,        // Collection (Application)
+	0x09, 0x01,        //   Usage (Pointer)
+	0xA1, 0x00,        //   Collection (Physical)
+	0x09, 0x30,        //     Usage (X)
+	0x09, 0x31,        //     Usage (Y)
+	0x15, 0x00,        //     Logical Minimum (0)
+	0x26, 0xFF, 0x07,  //     Logical Maximum (2047)
+	0x35, 0x00,        //     Physical Minimum (0)
+	0x46, 0xFF, 0x00,  //     Physical Maximum (255)
+	0x75, 0x10,        //     Report Size (16)
+	0x95, 0x02,        //     Report Count (2)
+	0x81, 0x02,        //     Input (Data,Var,Abs,No Wrap,Linear,Preferred State,No Null Position)
+	0xC0,              //   End Collection
+	0x75, 0x08,        //   Report Size (8)
+	0x95, 0x03,        //   Report Count (3)
+	0x81, 0x03,        //   Input (Cnst,Var,Abs)
+	0xC0,              // End Collection
+};
+
+static __u8 *vrc2_report_fixup(struct hid_device *hdev, __u8 *rdesc,
+				unsigned int *rsize)
+{
+	hid_info(hdev, "fixing up VRC-2 report descriptor\n");
+	*rsize = sizeof(vrc2_rdesc_fixed);
+	return vrc2_rdesc_fixed;
+}
+
+static int vrc2_probe(struct hid_device *hdev, const struct hid_device_id *id)
+{
+	int ret;
+
+	/*
+	 * The device gives us 2 separate USB endpoints.
+	 * One of those (the one with report descriptor size of 23) is just bogus so ignore it
+	 */
+	if (hdev->dev_rsize == 23)
+		return -ENODEV;
+
+	ret = hid_parse(hdev);
+	if (ret) {
+		hid_err(hdev, "parse failed\n");
+		return ret;
+	}
+
+	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
+	if (ret) {
+		hid_err(hdev, "hw start failed\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct hid_device_id vrc2_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_VRC2, USB_DEVICE_ID_VRC2) },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(hid, vrc2_devices);
+
+static struct hid_driver vrc2_driver = {
+	.name = "vrc2",
+	.id_table = vrc2_devices,
+	.report_fixup = vrc2_report_fixup,
+	.probe = vrc2_probe,
+};
+module_hid_driver(vrc2_driver);
+
+MODULE_AUTHOR("Marcus Folkesson <marcus.folkesson@gmail.com>");
+MODULE_DESCRIPTION("HID driver for VRC-2 2-axis Car controller");
+MODULE_LICENSE("GPL");