[1/1] Input: add gamecube adapter support

Add support for the Wii U / Nintendo Switch gamecube controller adapter

Signed-off-by: Milas Robin <milas.robin@live.fr>
---
 drivers/input/joystick/Kconfig            |  20 +
 drivers/input/joystick/Makefile           |   1 +
 drivers/input/joystick/gamecube-adapter.c | 607 ++++++++++++++++++++++
 3 files changed, 628 insertions(+)
 create mode 100644 drivers/input/joystick/gamecube-adapter.c

Hi Milas,

On Thu, Mar 28, 2024 at 03:06:51AM +0100, Milas Robin wrote:
> Add support for the Wii U / Nintendo Switch gamecube controller adapter

Thank you for the driver, a few comments below.

> 
> Signed-off-by: Milas Robin <milas.robin@live.fr>
> ---
>  drivers/input/joystick/Kconfig            |  20 +
>  drivers/input/joystick/Makefile           |   1 +
>  drivers/input/joystick/gamecube-adapter.c | 607 ++++++++++++++++++++++
>  3 files changed, 628 insertions(+)
>  create mode 100644 drivers/input/joystick/gamecube-adapter.c
> 
> diff --git a/drivers/input/joystick/Kconfig b/drivers/input/joystick/Kconfig
> index 7755e5b454d2..18ab1f893ed0 100644
> --- a/drivers/input/joystick/Kconfig
> +++ b/drivers/input/joystick/Kconfig
> @@ -422,4 +422,24 @@ config JOYSTICK_SEESAW
>  	  To compile this driver as a module, choose M here: the module will be
>  	  called adafruit-seesaw.
>  
> +config JOYSTICK_NGC
> +	tristate "Nintendo GameCube adapter support"
> +	depends on USB_ARCH_HAS_HCD
> +	select USB
> +	help
> +	  Say Y here if you want to use Nintendo GameCube adapter with
> +	  your computer.
> +	  Make sure to say Y to "Joystick support" (CONFIG_INPUT_JOYDEV)
> +	  and/or "Event interface support" (CONFIG_INPUT_EVDEV) as well.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called gamecube_adapter.
> +
> +config JOYSTICK_NGC_FF
> +	bool "Nintendo GameCube adapter rumble support"
> +	depends on JOYSTICK_NGC && INPUT
> +	select INPUT_FF_MEMLESS
> +	help
> +	  Say Y here if you want to take advantage of GameCube controller rumble features.
> +
>  endif
> diff --git a/drivers/input/joystick/Makefile b/drivers/input/joystick/Makefile
> index 9976f596a920..db0f137ba57f 100644
> --- a/drivers/input/joystick/Makefile
> +++ b/drivers/input/joystick/Makefile
> @@ -25,6 +25,7 @@ obj-$(CONFIG_JOYSTICK_JOYDUMP)		+= joydump.o
>  obj-$(CONFIG_JOYSTICK_MAGELLAN)		+= magellan.o
>  obj-$(CONFIG_JOYSTICK_MAPLE)		+= maplecontrol.o
>  obj-$(CONFIG_JOYSTICK_N64)		+= n64joy.o
> +obj-$(CONFIG_JOYSTICK_NGC)		+= gamecube-adapter.o
>  obj-$(CONFIG_JOYSTICK_PSXPAD_SPI)	+= psxpad-spi.o
>  obj-$(CONFIG_JOYSTICK_PXRC)		+= pxrc.o
>  obj-$(CONFIG_JOYSTICK_QWIIC)		+= qwiic-joystick.o
> diff --git a/drivers/input/joystick/gamecube-adapter.c b/drivers/input/joystick/gamecube-adapter.c
> new file mode 100644
> index 000000000000..85d69f39d732
> --- /dev/null
> +++ b/drivers/input/joystick/gamecube-adapter.c
> @@ -0,0 +1,607 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + *  Copyright (c) 2024 Milas Robin
> + *
> + *  Based on the work of:
> + *	Michael Lelli
> + *	Dolphin Emulator project
> + */
> +
> +#include <linux/usb.h>
> +#include <linux/module.h>
> +#include <linux/slab.h>
> +#include <linux/input.h>
> +#include <linux/usb/input.h>
> +
> +/* Did not use usb-hid as it is not an hid driver */
> +#define USB_VENDOR_ID_NINTENDO		0x057e
> +#define USB_DEVICE_ID_NINTENDO_GCADAPTER 0x0337
> +
> +#define EP_IN  0x81
> +#define EP_OUT 0x02
> +
> +#define GCC_OUT_PKT_LEN 5
> +#define GCC_IN_PKT_LEN 37
> +
> +enum gamecube_status {
> +	GAMECUBE_NONE,
> +	GAMECUBE_WIRED = 0x10,
> +	GAMECUBE_WIRELESS = 0x20,
> +};
> +
> +struct gcc_data {
> +	struct ngc_data *adapter;
> +	struct input_dev *input;
> +	u8 no;
> +	u8 status;
> +	bool enable;
> +};
> +
> +struct ngc_data {
> +	char phys[64];
> +
> +	struct usb_device *udev;
> +	struct usb_interface *intf;
> +
> +	struct urb *irq_in;
> +	u8 *idata;
> +	dma_addr_t idata_dma;
> +	spinlock_t idata_lock;
> +
> +	struct urb *irq_out;
> +	struct usb_anchor irq_out_anchor;
> +	u8 *odata;
> +	dma_addr_t odata_dma;
> +	spinlock_t odata_lock;		/* output data */
> +	bool irq_out_active;		/* we must not use an active URB */

I think all of this starting with irq_out should be under #ifdef
CONFIG_JOYSTICK_NGC_FF.

> +#ifdef CONFIG_JOYSTICK_NGC_FF
> +	u8 odata_rumbles[4];
> +	bool rumble_changed;		/* if rumble need update*/
> +#endif
> +
> +	struct gcc_data controllers[4];

Would be nice to have a #define for 4.

> +	struct work_struct work;	/* create/delete controller input files */
> +};
> +
> +#ifdef CONFIG_JOYSTICK_NGC_FF
> +/* Callers must hold gdata->odata_lock spinlock */

Then please use lockdep_assert_held().

> +static int ngc_queue_rumble(struct ngc_data *gdata)
> +{
> +	int error;
> +

Please check irq_out_active flag here and also provide a stub for
!CONFIG_JOYSTICK_NGC_FF so you do not need to sprinkle #ifdef checks..

> +	memcpy(gdata->odata + 1, gdata->odata_rumbles,
> +			 sizeof(gdata->odata_rumbles));
> +	gdata->irq_out_active = true;
> +	gdata->rumble_changed = false;
> +	gdata->odata[0] = 0x11;
> +	gdata->irq_out->transfer_buffer_length = 5;
> +
> +	usb_anchor_urb(gdata->irq_out, &gdata->irq_out_anchor);
> +	error = usb_submit_urb(gdata->irq_out, GFP_ATOMIC);
> +	if (error) {
> +		dev_err(&gdata->intf->dev,
> +			"%s - usb_submit_urb failed with result %d\n",
> +			__func__, error);
> +		usb_unanchor_urb(gdata->irq_out);
> +		error = -EIO;
> +	}
> +	return error;
> +}
> +
> +static int ngc_set_rumble_value(struct ngc_data *gdata, u8 controller, u8 value)

Since you want 0 or 1 for the value make it a "bool value".

> +{
> +	unsigned long flags;
> +	int error;
/
> +
> +	value = !!value;
> +	if (controller > 4)
> +		return -EINVAL;
> +
> +	spin_lock_irqsave(&gdata->odata_lock, flags);

Let's start using guard construct:

	guard(spinlock_irqsave)(&gdata->odata_lock);
	if (gdata->odata_rumbles[controller] == value)
		return 0;

	gdata->odata_rumbles[controller] = value;
	gdata->rumble_changed = true;
	
	return ngc_queue_rumble(gdata);


> +	if (gdata->odata_rumbles[controller] == value) {
> +		spin_unlock_irqrestore(&gdata->odata_lock, flags);
> +		return 0;
> +	}
> +	gdata->odata_rumbles[controller] = value;
> +	gdata->rumble_changed = true;
> +	if (!gdata->irq_out_active)
> +		error = ngc_queue_rumble(gdata);
> +	spin_unlock_irqrestore(&gdata->odata_lock, flags);
> +	return error;
> +}
> +
> +static int ngc_rumble_play(struct input_dev *dev, void *data,
> +			      struct ff_effect *eff)
> +{
> +	struct gcc_data *gccdata = input_get_drvdata(dev);
> +	u8 value;
> +
> +	/*
> +	 * The gamecube controller  supports only a single rumble motor so if any
> +	 * magnitude is set to non-zero then we start the rumble motor. If both are
> +	 * set to zero, we stop the rumble motor.
> +	 */
> +
> +	if (eff->u.rumble.strong_magnitude || eff->u.rumble.weak_magnitude)
> +		value = 1;
> +	else
> +		value = 0;
> +	return ngc_set_rumble_value(gccdata->adapter, gccdata->no, value);

If value is a bool you can simply say

	return ngc_set_rumble_value(gccdata->adapter, gccdata->no,
				    eff->u.rumble.strong_magnitude ||
					eff->u.rumble.weak_magnitude);

> +}
> +static int ngc_init_ff(struct gcc_data *gccdev)
> +{
> +	input_set_capability(gccdev->input, EV_FF, FF_RUMBLE);
> +
> +	return input_ff_create_memless(gccdev->input, NULL, ngc_rumble_play);
> +}
> +#else
> +static int ngc_init_ff(struct gcc_data *gccdev) { return 0; }
> +#endif
> +
> +static void ngc_irq_out(struct urb *urb)
> +{
> +	struct ngc_data *gdata = urb->context;
> +	struct device *dev = &gdata->intf->dev;
> +	int status = urb->status;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&gdata->odata_lock, flags);

	guard();

> +
> +	switch (status) {
> +	case 0:
> +		/* success */
> +#ifdef CONFIG_JOYSTICK_NGC_FF
> +		gdata->irq_out_active = gdata->rumble_changed;
> +#else
> +		gdata->irq_out_active = false;
> +#endif
> +		break;
> +	case -ECONNRESET:
> +	case -ENOENT:
> +	case -ESHUTDOWN:
> +		/* this urb is terminated, clean up */
> +		dev_dbg(dev, "%s - urb shutting down with status: %d\n",
> +			__func__, status);
> +		gdata->irq_out_active = false;

Do you really want to send out URB again in this case?

> +		break;
> +
> +	default:
> +		dev_dbg(dev, "%s - nonzero urb status received: %d\n",
> +			__func__, status);

And here?

> +		break;
> +	}
> +#ifdef CONFIG_JOYSTICK_NGC_FF
> +	if (gdata->irq_out_active)
> +		ngc_queue_rumble(gdata);
> +#endif
> +	spin_unlock_irqrestore(&gdata->odata_lock, flags);
> +}
> +
> +static int ngc_init_output(struct ngc_data *gdata,
> +			 struct usb_endpoint_descriptor *irq)
> +{
> +	int error = -ENOMEM;
> +
> +	init_usb_anchor(&gdata->irq_out_anchor);
> +
> +	gdata->odata = usb_alloc_coherent(gdata->udev, GCC_OUT_PKT_LEN, GFP_KERNEL,
> +			 &gdata->odata_dma);
> +	if (!gdata->odata)
> +		return error;
> +
> +	spin_lock_init(&gdata->odata_lock);
> +
> +	gdata->irq_out = usb_alloc_urb(0, GFP_KERNEL);
> +
> +	if (!gdata->irq_out)
> +		goto err_free_coherent;
> +
> +	usb_fill_int_urb(gdata->irq_out, gdata->udev,
> +			 usb_sndintpipe(gdata->udev, irq->bEndpointAddress),
> +			 gdata->odata, GCC_OUT_PKT_LEN, ngc_irq_out, gdata,
> +			 irq->bInterval);
> +	gdata->irq_out->transfer_dma = gdata->odata_dma;
> +	gdata->irq_out->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
> +	return 0;
> +
> +err_free_coherent:
> +	usb_free_coherent(gdata->udev, GCC_OUT_PKT_LEN, gdata->odata,
> +			 gdata->odata_dma);
> +	return error;
> +}
> +
> +static void ngc_deinit_output(struct ngc_data *gdata)
> +{
> +	usb_free_urb(gdata->irq_out);
> +	usb_free_coherent(gdata->udev, GCC_OUT_PKT_LEN, gdata->odata,
> +			 gdata->odata_dma);
> +}
> +
> +static void gcc_input(struct gcc_data *gccdata, const u8 *keys)
> +{
> +	input_report_key(gccdata->input, BTN_A, !!(keys[1] & BIT(0)));
> +	input_report_key(gccdata->input, BTN_B, !!(keys[1] & BIT(1)));
> +	input_report_key(gccdata->input, BTN_X, !!(keys[1] & BIT(2)));
> +	input_report_key(gccdata->input, BTN_Y, !!(keys[1] & BIT(3)));
> +	input_report_key(gccdata->input, BTN_DPAD_LEFT, !!(keys[1] & BIT(4)));
> +	input_report_key(gccdata->input, BTN_DPAD_RIGHT, !!(keys[1] & BIT(5)));
> +	input_report_key(gccdata->input, BTN_DPAD_DOWN, !!(keys[1] & BIT(6)));
> +	input_report_key(gccdata->input, BTN_DPAD_UP, !!(keys[1] & BIT(7)));
> +
> +	input_report_key(gccdata->input, BTN_START, !!(keys[2] & BIT(0)));
> +	input_report_key(gccdata->input, BTN_TR2, !!(keys[2] & BIT(1)));
> +	input_report_key(gccdata->input, BTN_TR, !!(keys[2] & BIT(2)));
> +	input_report_key(gccdata->input, BTN_TL, !!(keys[2] & BIT(3)));


Can we maybe have a list of mapping bits to events and loop over them.
You also do not need to normalize value for input_report_key(), it does
it for you.

> +
> +	input_report_abs(gccdata->input, ABS_X, keys[3]);
> +	input_report_abs(gccdata->input, ABS_Y, keys[4] ^ 0xFF);
> +	input_report_abs(gccdata->input, ABS_RX, keys[5]);
> +	input_report_abs(gccdata->input, ABS_RY, keys[6] ^ 0xFF);
> +	input_report_abs(gccdata->input, ABS_Z, keys[7]);
> +	input_report_abs(gccdata->input, ABS_RZ, keys[8]);
> +
> +	input_sync(gccdata->input);
> +}
> +
> +
> +static u8 ngc_connected_type(u8 status)
> +{
> +	u8 type = status & (GAMECUBE_WIRED | GAMECUBE_WIRELESS);
> +
> +	switch (type) {
> +	case GAMECUBE_WIRED:
> +	case GAMECUBE_WIRELESS:
> +		return type;
> +	default:
> +		return 0;
> +	}
> +}
> +
> +static int ngc_controller_init(struct gcc_data *gccdev, u8 status)
> +{
> +	int error;
> +
> +	gccdev->input = input_allocate_device();
> +	if (!gccdev->input)
> +		return -ENOMEM;
> +
> +	input_set_drvdata(gccdev->input, gccdev);
> +	usb_to_input_id(gccdev->adapter->udev, &gccdev->input->id);
> +	gccdev->input->name = "Nintendo GameCube Controller";
> +	gccdev->input->phys = gccdev->adapter->phys;
> +
> +	set_bit(EV_KEY, gccdev->input->evbit);
> +
> +	set_bit(BTN_A, gccdev->input->keybit);
> +	set_bit(BTN_B, gccdev->input->keybit);
> +	set_bit(BTN_X, gccdev->input->keybit);
> +	set_bit(BTN_Y, gccdev->input->keybit);
> +	set_bit(BTN_DPAD_LEFT, gccdev->input->keybit);
> +	set_bit(BTN_DPAD_RIGHT, gccdev->input->keybit);
> +	set_bit(BTN_DPAD_DOWN, gccdev->input->keybit);
> +	set_bit(BTN_DPAD_UP, gccdev->input->keybit);
> +	set_bit(BTN_START, gccdev->input->keybit);
> +	set_bit(BTN_TR2, gccdev->input->keybit);
> +	set_bit(BTN_TR, gccdev->input->keybit);
> +	set_bit(BTN_TL, gccdev->input->keybit);
> +
> +	set_bit(EV_ABS, gccdev->input->evbit);
> +
> +	set_bit(ABS_X, gccdev->input->absbit);
> +	set_bit(ABS_Y, gccdev->input->absbit);
> +	set_bit(ABS_RX, gccdev->input->absbit);
> +	set_bit(ABS_RY, gccdev->input->absbit);
> +	set_bit(ABS_Z, gccdev->input->absbit);
> +	set_bit(ABS_RZ, gccdev->input->absbit);

These bits will be set by input_set_abs_params() below.

> +
> +	input_set_abs_params(gccdev->input, ABS_X, 0, 255, 16, 16);
> +	input_set_abs_params(gccdev->input, ABS_Y, 0, 255, 16, 16);
> +	input_set_abs_params(gccdev->input, ABS_RX, 0, 255, 16, 16);
> +	input_set_abs_params(gccdev->input, ABS_RY, 0, 255, 16, 16);
> +	input_set_abs_params(gccdev->input, ABS_Z, 0, 255, 16, 0);
> +	input_set_abs_params(gccdev->input, ABS_RZ, 0, 255, 16, 0);
> +	error = ngc_init_ff(gccdev);
> +	if (error) {
> +		dev_warn(&gccdev->input->dev, "Could not create ff (skipped)");
> +		goto ngc_deinit_controller;
> +	}
> +	error = input_register_device(gccdev->input);
> +	if (error)
> +		goto ngc_deinit_controller_ff;
> +	gccdev->enable = true;
> +	return 0;
> +ngc_deinit_controller_ff:
> +	input_ff_destroy(gccdev->input);
> +ngc_deinit_controller:
> +	input_free_device(gccdev->input);
> +	return error;
> +}
> +
> +static void ngc_controller_update_work(struct work_struct *work)
> +{
> +	int i;
> +	u8 status[4];
> +	bool enable[4];
> +	unsigned long flags;
> +	struct ngc_data *gdata = container_of(work, struct ngc_data, work);
> +
> +	for (i = 0; i < 4; i++) {
> +		status[i] = gdata->controllers[i].status;
> +		enable[i] = ngc_connected_type(status[i]) != 0;
> +	}
> +
> +	for (i = 0; i < 4; i++) {
> +		if (enable[i] && !gdata->controllers[i].enable) {
> +			if (ngc_controller_init(&gdata->controllers[i], status[i]) != 0)
> +				enable[i] = false;
> +		}
> +	}
> +
> +	spin_lock_irqsave(&gdata->idata_lock, flags);
> +	for (i = 0; i < 4; i++)
> +		swap(gdata->controllers[i].enable, enable[i]);
> +	spin_unlock_irqrestore(&gdata->idata_lock, flags);
> +
> +	for (i = 0; i < 4; i++) {
> +		if (enable[i] && !gdata->controllers[i].enable)
> +			input_unregister_device(gdata->controllers[i].input);
> +	}
> +}
> +
> +static void ngc_input(struct ngc_data *gdata)
> +{
> +	int i;
> +	unsigned long flags;
> +	bool updated = false;
> +
> +	for (i = 0; i < 4; i++) {
> +		updated = updated ||
> +			 gdata->idata[1 + 9 * i] != gdata->controllers[i].status;
> +		gdata->controllers[i].status = gdata->idata[1 + 9 * i];
> +	}
> +	if (updated)
> +		schedule_work(&gdata->work);
> +	spin_lock_irqsave(&gdata->idata_lock, flags);
> +	for (i = 0; i < 4; i++) {
> +		if (gdata->controllers[i].enable)
> +			gcc_input(&gdata->controllers[i], &gdata->idata[1 + 9 * i]);
> +	}
> +	spin_unlock_irqrestore(&gdata->idata_lock, flags);
> +}
> +
> +static void ngc_irq_in(struct urb *urb)
> +{
> +	struct ngc_data *gdata = urb->context;
> +	struct usb_interface *intf = gdata->intf;
> +	int error;
> +
> +	switch (urb->status) {
> +	case 0:
> +		break;
> +	case -EOVERFLOW:
> +	case -ECONNRESET:
> +	case -ENOENT:
> +	case -ESHUTDOWN:
> +		dev_dbg(&intf->dev, "controller urb shutting down: %d\n",
> +			urb->status);
> +		return;
> +	default:
> +		dev_dbg(&intf->dev, "controller urb status: %d\n", urb->status);
> +		goto exit;
> +	}
> +	if (gdata->irq_in->actual_length != GCC_IN_PKT_LEN)
> +		dev_warn(&intf->dev, "Bad sized packet\n");
> +	else if (gdata->idata[0] != 0x21)
> +		dev_warn(&intf->dev, "Unknown opcode %d\n", gdata->idata[0]);
> +	else
> +		ngc_input(gdata);
> +exit:
> +	error = usb_submit_urb(gdata->irq_in, GFP_ATOMIC);
> +	if (error)
> +		dev_err(&intf->dev, "controller urb failed: %d\n", error);
> +}
> +
> +static int ngc_init_input(struct ngc_data *gdata,
> +			 struct usb_endpoint_descriptor *irq)
> +{
> +	int error = -ENOMEM;
> +
> +	gdata->idata = usb_alloc_coherent(gdata->udev, GCC_IN_PKT_LEN, GFP_KERNEL,
> +			 &gdata->idata_dma);
> +	if (!gdata->idata)
> +		return error;
> +
> +	gdata->irq_in = usb_alloc_urb(0, GFP_KERNEL);
> +	if (!gdata->irq_in)
> +		goto err_free_coherent;
> +
> +	usb_fill_int_urb(gdata->irq_in, gdata->udev,
> +			 usb_rcvintpipe(gdata->udev, irq->bEndpointAddress),
> +			 gdata->idata, GCC_IN_PKT_LEN, ngc_irq_in, gdata,
> +			 irq->bInterval);
> +	gdata->irq_in->transfer_dma = gdata->idata_dma;
> +	gdata->irq_in->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
> +
> +	spin_lock_init(&gdata->idata_lock);
> +	INIT_WORK(&gdata->work, ngc_controller_update_work);
> +
> +	return 0;
> +
> +err_free_coherent:
> +	usb_free_coherent(gdata->udev, GCC_IN_PKT_LEN, gdata->idata,
> +			 gdata->idata_dma);
> +	return error;
> +
> +}
> +
> +
> +static void ngc_deinit_input(struct ngc_data *gdata)
> +{
> +	usb_free_urb(gdata->irq_in);
> +	usb_free_coherent(gdata->udev, GCC_IN_PKT_LEN, gdata->idata,
> +			 gdata->idata_dma);
> +}
> +
> +
> +static int ngc_init_irq(struct ngc_data *gdata)
> +{
> +	struct usb_endpoint_descriptor *eps[] = { NULL, NULL };
> +	int error;
> +
> +	error = usb_find_common_endpoints(gdata->intf->cur_altsetting, NULL, NULL,
> +					  &eps[0], &eps[1]);
> +	if (error)
> +		return -ENODEV;
> +	error = ngc_init_output(gdata, eps[1]);
> +	if (error)
> +		return error;
> +	error = ngc_init_input(gdata, eps[0]);
> +	if (error)
> +		goto err_deinit_out;
> +#ifdef CONFIG_JOYSTICK_NGC_FF
> +	memset(gdata->odata_rumbles, 0, 4);
> +	gdata->rumble_changed = false;

Don't you allocate zeroed out memory?

> +#endif
> +	gdata->irq_out_active = true;
> +	gdata->odata[0] = 0x13;
> +	gdata->irq_out->transfer_buffer_length = 1;
> +
> +	error = usb_submit_urb(gdata->irq_in, GFP_KERNEL);
> +	if (error)
> +		goto err_deinit_in;
> +
> +	usb_anchor_urb(gdata->irq_out, &gdata->irq_out_anchor);
> +	error = usb_submit_urb(gdata->irq_out, GFP_ATOMIC);
> +	if (error) {
> +		dev_err(&gdata->intf->dev,
> +			"%s - usb_submit_urb failed with result %d\n",
> +			__func__, error);
> +		usb_unanchor_urb(gdata->irq_out);
> +		error = -EIO;
> +		goto err_kill_in_urb;
> +	}
> +
> +	return 0;
> +err_kill_in_urb:
> +	usb_kill_urb(gdata->irq_in);
> +err_deinit_in:
> +	ngc_deinit_input(gdata);
> +err_deinit_out:
> +	ngc_deinit_output(gdata);
> +	return error;
> +}
> +
> +static void ngc_deinit_irq(struct ngc_data *gdata)
> +{
> +	if (!usb_wait_anchor_empty_timeout(&gdata->irq_out_anchor, 5000)) {
> +		dev_warn(&gdata->intf->dev,
> +			 "timed out waiting for output URB to complete, killing\n");
> +		usb_kill_anchored_urbs(&gdata->irq_out_anchor);

Why can't we simply kill out URB and not dean with anchoring?

> +	}
> +	usb_kill_urb(gdata->irq_in);
> +	/* Make sure we are done with presence work if it was scheduled */
> +	flush_work(&gdata->work);
> +
> +	ngc_deinit_input(gdata);
> +	ngc_deinit_output(gdata);
> +}
> +
> +static void ngc_init_controllers(struct ngc_data *gdata)
> +{
> +	int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(gdata->controllers); i++) {
> +		gdata->controllers[i].adapter = gdata;
> +		gdata->controllers[i].no = i;
> +		gdata->controllers[i].status = GAMECUBE_NONE;
> +		gdata->controllers[i].enable = false;
> +	}
> +}
> +
> +static struct attribute *ngc_attrs[] = {
> +	NULL,
> +};
> +
> +static const struct attribute_group ngc_attr_group = {
> +	.attrs = ngc_attrs,
> +};
> +
> +static int ngc_init_attr(struct ngc_data *gdata)
> +{
> +	return sysfs_create_group(&gdata->intf->dev.kobj, &ngc_attr_group);
> +}
> +
> +static void ngc_deinit_attr(struct ngc_data *gdata)
> +{
> +	sysfs_remove_group(&gdata->intf->dev.kobj, &ngc_attr_group);
> +}

What is all this for?

> +
> +
> +static int ngc_usb_probe(struct usb_interface *iface, const struct usb_device_id *id)
> +{
> +	struct usb_device *udev = interface_to_usbdev(iface);
> +	struct ngc_data *gdata;
> +	int error;
> +
> +	gdata = kzalloc(sizeof(struct ngc_data), GFP_KERNEL);
> +	if (!gdata)
> +		return -ENOMEM;
> +	usb_set_intfdata(iface, gdata);
> +	gdata->udev = udev;
> +	gdata->intf = iface;
> +
> +	usb_make_path(udev, gdata->phys, sizeof(gdata->phys));
> +	strlcat(gdata->phys, "/input0", sizeof(gdata->phys));
> +
> +	ngc_init_controllers(gdata);
> +	error = ngc_init_irq(gdata);
> +	if (error)
> +		goto err_free_devs;
> +	error = ngc_init_attr(gdata);
> +	if (error)
> +		goto err_deinit_endpoints;
> +	dev_info(&iface->dev, "New device registered\n");
> +	return 0;
> +err_deinit_endpoints:
> +	ngc_deinit_irq(gdata);
> +err_free_devs:
> +	usb_set_intfdata(iface, NULL);
> +	kfree(gdata);
> +	return error;
> +}
> +
> +static void ngc_usb_disconnect(struct usb_interface *iface)
> +{
> +	int i;
> +	struct ngc_data *gdata = usb_get_intfdata(iface);

Make this first line.

> +
> +	for (i = 0; i < 4; i++) {
> +		if (gdata->controllers[i].enable)
> +			input_unregister_device(gdata->controllers[i].input);
> +	}
> +	ngc_deinit_attr(gdata);
> +	ngc_deinit_irq(gdata);
> +	usb_set_intfdata(iface, NULL);
> +	kfree(gdata);
> +}
> +
> +static const struct usb_device_id ngc_usb_devices[] = {
> +	{ USB_DEVICE(USB_VENDOR_ID_NINTENDO,
> +		     USB_DEVICE_ID_NINTENDO_GCADAPTER) },
> +	{}
> +};
> +

Drop empty line.

> +MODULE_DEVICE_TABLE(usb, ngc_usb_devices);
> +
> +static struct usb_driver ngc_usb_driver = {
> +	.name		= "gamecube_adapter",
> +	.id_table	= ngc_usb_devices,
> +	.probe		= ngc_usb_probe,
> +	.disconnect	= ngc_usb_disconnect,
> +};
> +
> +module_usb_driver(ngc_usb_driver);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("Robin Milas <milas.robin@live.fr>");
> +MODULE_DESCRIPTION("Driver for GameCube adapter");
> -- 
> 2.44.0
> 

Thanks.