Re: [PATCH] HID: gembird: add new driver to fix Gembird JPD-DualForce 2

[Orivej Desh <orivej@gmx.fr>]

This gamepad advertises 5 absolute axis while 4 are actually used.
The first Z axis shows some garbage, so it has to be ignored by HID.
The second Z axis and the Rz one are actually Rx and Ry. Remap them.

We could also just remap and ignore the axis in .input_mapping(). I
went ahead with .report_fixup() first, so here it is.

Reported-by: Orivej Desh <orivej@gmx.fr>
Tested-by: Orivej Desh <orivej@gmx.fr>
---

* Benjamin Tissoires
> so here are the fixes I mentioned yesterday. If you could give a quick shot
> and a "tested-by" that would be even better.

I tested your patch and it works as advertised, thank you!  But your
comment about the implementation («re-assigning X to the original Z
axis») did not match the implementation, so I simplified the
implementation according to the comment, and tested it too.  Since the
patch has changed, I think you need to sign it off again.

> Jiri, I am not sure if the .input_mapping() alternative would not be better.
> Both solutions are valid, so if you do not like my memcpys, I can re-write the
> patch the other way.

 drivers/hid/Kconfig       |  6 ++++
 drivers/hid/Makefile      |  1 +
 drivers/hid/hid-core.c    |  1 +
 drivers/hid/hid-gembird.c | 77 +++++++++++++++++++++++++++++++++++++++++++++++
 drivers/hid/hid-ids.h     |  3 ++
 5 files changed, 88 insertions(+)
 create mode 100644 drivers/hid/hid-gembird.c

diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
index 57c94d7..6ab51ae 100644
--- a/drivers/hid/Kconfig
+++ b/drivers/hid/Kconfig
@@ -251,6 +251,12 @@ config HID_EZKEY
 	---help---
 	Support for Ezkey BTC 8193 keyboard.
 
+config HID_GEMBIRD
+	tristate "Gembird Joypad"
+	depends on HID
+	---help---
+	Support for Gembird JPD-DualForce 2.
+
 config HID_HOLTEK
 	tristate "Holtek HID devices"
 	depends on USB_HID
diff --git a/drivers/hid/Makefile b/drivers/hid/Makefile
index 2f8a41d..e6441bc 100644
--- a/drivers/hid/Makefile
+++ b/drivers/hid/Makefile
@@ -36,6 +36,7 @@ obj-$(CONFIG_HID_EMS_FF)	+= hid-emsff.o
 obj-$(CONFIG_HID_ELECOM)	+= hid-elecom.o
 obj-$(CONFIG_HID_ELO)		+= hid-elo.o
 obj-$(CONFIG_HID_EZKEY)		+= hid-ezkey.o
+obj-$(CONFIG_HID_GEMBIRD)	+= hid-gembird.o
 obj-$(CONFIG_HID_GT683R)	+= hid-gt683r.o
 obj-$(CONFIG_HID_GYRATION)	+= hid-gyration.o
 obj-$(CONFIG_HID_HOLTEK)	+= hid-holtek-kbd.o
diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index e982e70..22afab9 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -1844,6 +1844,7 @@ static const struct hid_device_id hid_have_special_driver[] = {
 	{ HID_USB_DEVICE(USB_VENDOR_ID_EZKEY, USB_DEVICE_ID_BTC_8193) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_GAMERON, USB_DEVICE_ID_GAMERON_DUAL_PSX_ADAPTOR) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_GAMERON, USB_DEVICE_ID_GAMERON_DUAL_PCS_ADAPTOR) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_GEMBIRD, USB_DEVICE_ID_GEMBIRD_JPD_DUALFORCE2) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_GREENASIA, 0x0003) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_GREENASIA, 0x0012) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_GYRATION, USB_DEVICE_ID_GYRATION_REMOTE) },
diff --git a/drivers/hid/hid-gembird.c b/drivers/hid/hid-gembird.c
new file mode 100644
index 0000000..cefc394
--- /dev/null
+++ b/drivers/hid/hid-gembird.c
@@ -0,0 +1,77 @@
+/*
+ *  HID driver for Gembird Joypad, "PC Game Controller"
+ *
+ *  Copyright (c) 2015 Red Hat, Inc
+ *  Copyright (c) 2015 Benjamin Tissoires
+ */
+
+/*
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ */
+
+#include <linux/device.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+
+#include "hid-ids.h"
+
+#define GEMBIRD_START_FAULTY_RDESC	22
+
+/*
+ * This gamepad advertises 5 absolute axis while 4 are actually used.
+ * The first Z axis shows some garbage, so it has to be ignored by HID.
+ * The second Z axis and the Rz one are actually Rx and Ry. Remap them.
+ */
+
+static const __u8 gembird_jpd_faulty_rdesc[] = {
+	0x09, 0x30,			/*   Usage (X)			*/
+	0x09, 0x31,			/*   Usage (Y)			*/
+	0x09, 0x32,			/*   Usage (Z)			*/
+	0x09, 0x32,			/*   Usage (Z)			*/
+	0x09, 0x35,			/*   Usage (Rz)			*/
+};
+static const __u8 gembird_jpd_fixed_rdesc[] = {
+	0x09, 0x30,			/*   Usage (X)			*/
+	0x09, 0x31,			/*   Usage (Y)			*/
+	0x09, 0x30,			/*   Usage (X) (ignored)	*/
+	0x09, 0x33,			/*   Usage (Rx)			*/
+	0x09, 0x34,			/*   Usage (Ry)			*/
+};
+
+static __u8 *gembird_report_fixup(struct hid_device *hdev, __u8 *rdesc,
+		unsigned int *rsize)
+{
+	if (*rsize >= 32 && !memcmp(&rdesc[GEMBIRD_START_FAULTY_RDESC],
+				    gembird_jpd_faulty_rdesc,
+				    sizeof(gembird_jpd_faulty_rdesc))) {
+		dev_info(&hdev->dev,
+			 "fixing Gembird JPD-DualForce 2 report descriptor.\n");
+
+		memcpy(rdesc + GEMBIRD_START_FAULTY_RDESC,
+		       gembird_jpd_fixed_rdesc,
+		       sizeof(gembird_jpd_fixed_rdesc));
+	}
+
+	return rdesc;
+}
+
+static const struct hid_device_id gembird_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_GEMBIRD,
+			 USB_DEVICE_ID_GEMBIRD_JPD_DUALFORCE2) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, gembird_devices);
+
+static struct hid_driver gembird_driver = {
+	.name = "gembird",
+	.id_table = gembird_devices,
+	.report_fixup = gembird_report_fixup,
+};
+module_hid_driver(gembird_driver);
+
+MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@gmail.com>");
+MODULE_DESCRIPTION("HID Gembird joypad driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/hid/hid-ids.h b/drivers/hid/hid-ids.h
index 602f2b7..720d5e3 100644
--- a/drivers/hid/hid-ids.h
+++ b/drivers/hid/hid-ids.h
@@ -363,6 +363,9 @@
 #define USB_DEVICE_ID_GAMERON_DUAL_PSX_ADAPTOR	0x0001
 #define USB_DEVICE_ID_GAMERON_DUAL_PCS_ADAPTOR	0x0002
 
+#define USB_VENDOR_ID_GEMBIRD			0x11ff
+#define USB_DEVICE_ID_GEMBIRD_JPD_DUALFORCE2	0x3331
+
 #define USB_VENDOR_ID_GENERAL_TOUCH	0x0dfc
 #define USB_DEVICE_ID_GENERAL_TOUCH_WIN7_TWOFINGERS 0x0003
 #define USB_DEVICE_ID_GENERAL_TOUCH_WIN8_PWT_TENFINGERS 0x0100
-- 
2.4.3