Driver written, will it work?

1 files changed, 230 insertions, 0 deletions

diff --git a/hid-tminit.c b/hid-tminit.c
new file mode 100644
index 0000000..219d78c
--- /dev/null
+++ b/hid-tminit.c
@@ -0,0 +1,230 @@
+// SPDX-License-Identifier: GPL-2.0
+/**
+ * When connected to the machine, the Thrustmaster wheels appear as
+ * a «generic» hid gamepad called "Thrustmaster FFB Wheel".
+ * 
+ * When in this mode not every functionality of the wheel, like the force feedback,
+ * are available. To enable all functionalities of a Thrustmaster wheel we have to send
+ * to it a specific USB CONTROL request with a code different for each wheel.
+ *
+ * This driver tries to understand which model of Thrustmaster wheel the generic
+ * "Thrustmaster FFB Wheel" really is and then sends the appropriate control code.
+ */
+#include <linux/hid.h>
+#include <linux/usb.h>
+#include <linux/input.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include "hid-tminit.h"
+
+static void tminit_change_handler(struct urb *urb)
+{
+	struct hid_device *hdev = urb->context;
+
+	// The wheel seems to kill himself before answering the host and therefore is violating the USB protocol...
+	if(urb->status == 0 || urb->status == -EPROTO)
+		hid_info(hdev, "Success?! The wheel should have been initialized!\n");
+	else
+		hid_err(hdev, "URB to change wheel mode failed with error %d\n", urb->status);
+}
+
+/**
+ * Called by the USB subsystem when the wheel respons to our request
+ * to get [what it seems to be] the wheel's model.
+ * 
+ * If the model id is recognized then we send an opportune USB CONTROL REQUEST
+ * to switch the wheel to its full capabilities
+ */
+static void tminit_model_handler(struct urb *urb)
+{
+	struct hid_device *hdev = urb->context;
+	struct tm_wheel *tm_wheel = hid_get_drvdata(hdev);
+	uint16_t model = 0;
+	int i, ret;
+	const struct th_wheel_info *twi = 0;
+
+	if(urb->status)
+	{
+		hid_err(hdev, "URB to get model id failed with error %d\n", urb->status);
+		return;
+	}
+
+	if(tm_wheel->response->type == cpu_to_le16(0x49))
+		model = le16_to_cpu(tm_wheel->response->data.a.model);
+	else if(tm_wheel->response->type == cpu_to_le16(0x47))
+		model = le16_to_cpu(tm_wheel->response->data.b.model);
+	else
+	{
+		hid_err(hdev, "Unknow packet type 0x%x, unable to proceed further with wheel init\n", tm_wheel->response->type);
+		return;
+	}
+
+	for(i = 0; i < th_wheels_infos_length && !twi; i++)
+		if(th_wheels_infos[i].wheel_type == model)
+			twi = th_wheels_infos + i;
+	
+	if(twi)
+		hid_info(hdev, "Wheel with model id 0x%x is a %s\n", model, twi->wheel_name);
+	else
+	{
+		hid_err(hdev, "Unknown wheel's model id 0x%x, unable to proceed further with wheel init\n",model);
+		return;
+	}
+	
+	tm_wheel->change_request->wValue = cpu_to_le16(twi->switch_value);
+	usb_fill_control_urb(
+		tm_wheel->urb,
+		tm_wheel->usb_dev,
+		usb_sndctrlpipe(tm_wheel->usb_dev, 0),
+		(char*)tm_wheel->change_request,
+		0, 0, // We do not expect any response from the wheel
+		tminit_change_handler,
+		hdev
+	);
+
+	ret = usb_submit_urb(tm_wheel->urb, GFP_ATOMIC);
+	if(ret)
+		hid_err(hdev, "Error %d while submitting the change URB. I am unable to initialize this wheel...\n", ret);
+}
+
+static void tminit_remove(struct hid_device *hdev)
+{
+	struct tm_wheel *tm_wheel = hid_get_drvdata(hdev);
+
+	usb_kill_urb(tm_wheel->urb);
+
+	kzfree(tm_wheel->response);
+	kzfree(tm_wheel->model_request);
+	usb_free_urb(tm_wheel->urb);
+	kzfree(tm_wheel);
+
+	hid_hw_stop(hdev);
+}
+
+/**
+ * Function called by HID when a hid Thrustmaster FFB wheel is connected to the host.
+ * This function starts the hid dev, tries to allocate the tm_wheel data structure and
+ * finally send an USB CONTROL REQUEST to the wheel to get [what it seems to be] its
+ * model type. 
+ */
+static int tminit_probe(struct hid_device *hdev, const struct hid_device_id *id){
+	int ret = 0;
+	struct tm_wheel *tm_wheel = 0;
+
+	ret = hid_parse(hdev);
+	if(ret)
+	{
+		hid_err(hdev, "parse failed with error %d\n", ret);
+		goto error0;
+	}
+
+	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT & ~HID_CONNECT_FF);
+	if(ret)
+	{
+		hid_err(hdev, "hw start failed with error %d\n", ret);
+		goto error0;
+	}
+
+	// Now we allocate the tm_wheel
+	tm_wheel = kzalloc(sizeof(struct tm_wheel), GFP_KERNEL);
+	if(!tm_wheel)
+	{
+		ret = -ENOMEM;
+		goto error1;
+	}
+
+	tm_wheel->urb = usb_alloc_urb(0, GFP_ATOMIC);
+	if(!tm_wheel->urb)
+	{
+		ret = -ENOMEM;
+		goto error2;
+	}
+
+	tm_wheel->model_request = kzalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
+	if(! tm_wheel->model_request)
+	{
+		ret = -ENOMEM;
+		goto error3;
+	}
+	memcpy(tm_wheel->model_request, &model_request, sizeof(struct usb_ctrlrequest));
+
+	tm_wheel->response = kzalloc(sizeof(struct tm_wheel_response), GFP_KERNEL);
+	if(! tm_wheel->response)
+	{
+		ret = -ENOMEM;
+		goto error4;
+	}
+
+	tm_wheel->change_request = kzalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
+	if(! tm_wheel->model_request)
+	{
+		ret = -ENOMEM;
+		goto error5;
+	}
+	memcpy(tm_wheel->change_request, &change_request, sizeof(struct usb_ctrlrequest));
+
+	tm_wheel->usb_dev = interface_to_usbdev(to_usb_interface(hdev->dev.parent));
+	hid_set_drvdata(hdev, tm_wheel);
+
+	usb_fill_control_urb(
+		tm_wheel->urb,
+		tm_wheel->usb_dev,
+		usb_sndctrlpipe(tm_wheel->usb_dev, 0),
+		(char*)tm_wheel->model_request,
+		tm_wheel->response,
+		sizeof(struct tm_wheel_response),
+		tminit_model_handler,
+		hdev
+	);
+
+	ret = usb_submit_urb(tm_wheel->urb, GFP_ATOMIC);
+	if(ret)
+		hid_err(hdev, "Error %d while submitting the URB. I am unable to initialize this wheel...\n", ret);
+
+	return ret;
+
+error5: kzfree(tm_wheel->response);
+error4:	kzfree(tm_wheel->model_request);
+error3:	usb_free_urb(tm_wheel->urb);
+error2:	kzfree(tm_wheel);
+error1:	hid_hw_stop(hdev);
+error0:
+	return ret; 
+}
+
+static const struct hid_device_id tminit_devices[] = {
+	{ HID_USB_DEVICE(0x044f, 0xb65d)},
+	{}
+};
+
+MODULE_DEVICE_TABLE(hid, tminit_devices);
+
+static struct hid_driver tminit_driver = {
+	.name = "hid-tminit",
+	.id_table = tminit_devices,
+	.probe = tminit_probe,
+	.remove = tminit_remove,
+};
+
+static int __init tminit_init(void)
+{
+	int errno;
+
+	errno = hid_register_driver(&tminit_driver);
+
+	if(errno)
+		printk(KERN_ERR "hid-tminit: error %d while registering the hid driver\n", errno);
+
+	return errno;
+}
+
+static void __exit tminit_exit(void)
+{
+	hid_unregister_driver(&tminit_driver);
+}
+
+module_init(tminit_init);
+module_exit(tminit_exit);
+
+MODULE_AUTHOR("Dario Pagani <>");
+MODULE_LICENSE("GPL");