Message-ID: <20180116231625.e3sgum667xfuumx4@dtor-ws>
Date:   Tue, 16 Jan 2018 15:16:25 -0800
From:   Dmitry Torokhov <dmitry.torokhov@...il.com>
To:     Marcus Folkesson <marcus.folkesson@...il.com>
Cc:     Jonathan Corbet <corbet@....net>,
        Tomohiro Yoshidomi <sylph23k@...il.com>,
        David Herrmann <dh.herrmann@...il.com>,
        Philippe Ombredanne <pombredanne@...b.com>,
        Kate Stewart <kstewart@...uxfoundation.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-input@...r.kernel.org, linux-doc@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] input: pxrc: new driver for PhoenixRC Flight
 Controller Adapter

Hi Marcus,

On Sat, Jan 13, 2018 at 09:15:32PM +0100, Marcus Folkesson wrote:
> This driver let you plug in your RC controller to the adapter and
> use it as input device in various RC simulators.
> 
> Signed-off-by: Marcus Folkesson <marcus.folkesson@...il.com>
> ---
> v3:
> 	- Use RUDDER and MISC instead of TILT_X and TILT_Y
> 	- Drop kref and anchor
> 	- Rework URB handling
> 	- Add PM support

How did you test the PM support? By default the autopm is disabled on
USB devices; you need to enable it by writing to sysfs (I believe you
need to 'echo "auto" > /sys/bus/usb/<device>/power/control) and see if
it gets autosuspended when not in use and resumed after you start
interacting with it.

> v2:
> 	- Change module license to GPLv2 to match SPDX tag
> 
>  Documentation/input/devices/pxrc.rst |  57 +++++++
>  drivers/input/joystick/Kconfig       |   9 +
>  drivers/input/joystick/Makefile      |   1 +
>  drivers/input/joystick/pxrc.c        | 320 +++++++++++++++++++++++++++++++++++
>  4 files changed, 387 insertions(+)
>  create mode 100644 Documentation/input/devices/pxrc.rst
>  create mode 100644 drivers/input/joystick/pxrc.c
> 
> diff --git a/Documentation/input/devices/pxrc.rst b/Documentation/input/devices/pxrc.rst
> new file mode 100644
> index 000000000000..ca11f646bae8
> --- /dev/null
> +++ b/Documentation/input/devices/pxrc.rst
> @@ -0,0 +1,57 @@
> +=======================================================
> +pxrc - PhoenixRC Flight Controller Adapter
> +=======================================================
> +
> +:Author: Marcus Folkesson <marcus.folkesson@...il.com>
> +
> +This driver let you use your own RC controller plugged into the
> +adapter that comes with PhoenixRC [1]_ or other compatible adapters.
> +
> +The adapter supports 7 analog channels and 1 digital input switch.
> +
> +Notes
> +=====
> +
> +Many RC controllers is able to configure which stick goes to which channel.
> +This is also configurable in most simulators, so a matching is not necessary.
> +
> +The driver is generating the following input event for analog channels:
> +
> ++---------+----------------+
> +| Channel |      Event     |
> ++=========+================+
> +|     1   |  ABS_X         |
> ++---------+----------------+
> +|     2   |  ABS_Y         |
> ++---------+----------------+
> +|     3   |  ABS_RX        |
> ++---------+----------------+
> +|     4   |  ABS_RY        |
> ++---------+----------------+
> +|     5   |  ABS_RUDDER    |
> ++---------+----------------+
> +|     6   |  ABS_THROTTLE  |
> ++---------+----------------+
> +|     7   |  ABS_MISC      |
> ++---------+----------------+
> +
> +The digital input switch is generated as an `BTN_A` event.
> +
> +Manual Testing
> +==============
> +
> +To test this driver's functionality you may use `input-event` which is part of
> +the `input layer utilities` suite [2]_.
> +
> +For example::
> +
> +    > modprobe pxrc
> +    > input-events <devnr>
> +
> +To print all input events from input `devnr`.
> +
> +References
> +==========
> +
> +.. [1] http://www.phoenix-sim.com/
> +.. [2] https://www.kraxel.org/cgit/input/
> diff --git a/drivers/input/joystick/Kconfig b/drivers/input/joystick/Kconfig
> index f3c2f6ea8b44..18ab6dafff41 100644
> --- a/drivers/input/joystick/Kconfig
> +++ b/drivers/input/joystick/Kconfig
> @@ -351,4 +351,13 @@ config JOYSTICK_PSXPAD_SPI_FF
>  
>  	  To drive rumble motor a dedicated power supply is required.
>  
> +config JOYSTICK_PXRC
> +	tristate "PhoenixRC Flight Controller Adapter"
> +	depends on USB_ARCH_HAS_HCD
> +	select USB
> +	help
> +	  Say Y here if you want to use the PhoenixRC Flight Controller Adapter.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called pxrc.
>  endif
> diff --git a/drivers/input/joystick/Makefile b/drivers/input/joystick/Makefile
> index 67651efda2e1..dd0492ebbed7 100644
> --- a/drivers/input/joystick/Makefile
> +++ b/drivers/input/joystick/Makefile
> @@ -23,6 +23,7 @@ obj-$(CONFIG_JOYSTICK_JOYDUMP)		+= joydump.o
>  obj-$(CONFIG_JOYSTICK_MAGELLAN)		+= magellan.o
>  obj-$(CONFIG_JOYSTICK_MAPLE)		+= maplecontrol.o
>  obj-$(CONFIG_JOYSTICK_PSXPAD_SPI)	+= psxpad-spi.o
> +obj-$(CONFIG_JOYSTICK_PXRC)			+= pxrc.o
>  obj-$(CONFIG_JOYSTICK_SIDEWINDER)	+= sidewinder.o
>  obj-$(CONFIG_JOYSTICK_SPACEBALL)	+= spaceball.o
>  obj-$(CONFIG_JOYSTICK_SPACEORB)		+= spaceorb.o
> diff --git a/drivers/input/joystick/pxrc.c b/drivers/input/joystick/pxrc.c
> new file mode 100644
> index 000000000000..98d9b8184c46
> --- /dev/null
> +++ b/drivers/input/joystick/pxrc.c
> @@ -0,0 +1,320 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Driver for Phoenix RC Flight Controller Adapter
> + *
> + * Copyright (C) 2018 Marcus Folkesson <marcus.folkesson@...il.com>
> + *
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/errno.h>
> +#include <linux/slab.h>
> +#include <linux/module.h>
> +#include <linux/uaccess.h>
> +#include <linux/usb.h>
> +#include <linux/usb/input.h>
> +#include <linux/mutex.h>
> +#include <linux/input.h>
> +
> +#define PXRC_VENDOR_ID	(0x1781)
> +#define PXRC_PRODUCT_ID	(0x0898)
> +
> +static const struct usb_device_id pxrc_table[] = {
> +	{ USB_DEVICE(PXRC_VENDOR_ID, PXRC_PRODUCT_ID) },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(usb, pxrc_table);
> +
> +struct pxrc {
> +	struct input_dev	*input;
> +	struct usb_device	*udev;
> +	struct usb_interface	*intf;
> +	struct urb		*urb;
> +	__u8			epaddr;
> +	char			phys[64];
> +	unsigned char           *data;
> +	size_t			bsize;
> +};
> +
> +static void pxrc_usb_irq(struct urb *urb)
> +{
> +	struct pxrc *pxrc = urb->context;
> +	int error;
> +
> +	switch (urb->status) {
> +	case 0:
> +		/* success */
> +		break;
> +	case -ETIME:
> +		/* this urb is timing out */
> +		dev_dbg(&pxrc->intf->dev,
> +			"%s - urb timed out - was the device unplugged?\n",
> +			__func__);
> +		return;
> +	case -ECONNRESET:
> +	case -ENOENT:
> +	case -ESHUTDOWN:
> +	case -EPIPE:
> +		/* this urb is terminated, clean up */
> +		dev_dbg(&pxrc->intf->dev, "%s - urb shutting down with status: %d\n",
> +			__func__, urb->status);
> +		return;
> +	default:
> +		dev_dbg(&pxrc->intf->dev, "%s - nonzero urb status received: %d\n",
> +			__func__, urb->status);
> +		goto exit;
> +	}
> +
> +	if (urb->actual_length == 8) {
> +		input_report_abs(pxrc->input, ABS_X, pxrc->data[0]);
> +		input_report_abs(pxrc->input, ABS_Y, pxrc->data[2]);
> +		input_report_abs(pxrc->input, ABS_RX, pxrc->data[3]);
> +		input_report_abs(pxrc->input, ABS_RY, pxrc->data[4]);
> +		input_report_abs(pxrc->input, ABS_RUDDER, pxrc->data[5]);
> +		input_report_abs(pxrc->input, ABS_THROTTLE, pxrc->data[6]);
> +		input_report_abs(pxrc->input, ABS_MISC, pxrc->data[7]);
> +
> +		input_report_key(pxrc->input, BTN_A, pxrc->data[1]);
> +	}
> +
> +exit:

I think you need

	usb_mark_last_busy(interface_to_usbdev(pxrc->intf));

here.

> +	/* Resubmit to fetch new fresh URBs */
> +	error = usb_submit_urb(urb, GFP_ATOMIC);
> +	if (error && error != -EPERM)
> +		dev_err(&pxrc->intf->dev,
> +			"%s - usb_submit_urb failed with result: %d",
> +			__func__, error);
> +}
> +
> +static int pxrc_open(struct input_dev *input)
> +{
> +	struct pxrc *pxrc = input_get_drvdata(input);
> +	int retval;
> +
> +	retval = usb_autopm_get_interface(pxrc->intf);
> +	if (retval) {
> +		dev_err(&pxrc->intf->dev,
> +			"%s - usb_autopm_get_interface failed, error: %d\n",
> +			__func__, retval);
> +		return retval;
> +	}
> +
> +	retval = usb_submit_urb(pxrc->urb, GFP_KERNEL);
> +	if (retval) {
> +		dev_err(&pxrc->intf->dev,
> +			"%s - usb_submit_urb failed, error: %d\n",
> +			__func__, retval);
> +		retval = -EIO;
> +		goto out;
> +	}
> +
> +	pxrc->intf->needs_remote_wakeup = 1;
> +
> +out:
> +	usb_autopm_put_interface(pxrc->intf);
> +	return retval;
> +}
> +
> +static void pxrc_close(struct input_dev *input)
> +{
> +	struct pxrc *pxrc = input_get_drvdata(input);
> +	int autopm_error;
> +
> +	autopm_error = usb_autopm_get_interface(pxrc->intf);
> +
> +	usb_kill_urb(pxrc->urb);
> +	pxrc->intf->needs_remote_wakeup = 0;
> +
> +	if (!autopm_error)
> +		usb_autopm_put_interface(pxrc->intf);
> +}
> +
> +static int pxrc_usb_init(struct pxrc *pxrc)
> +{
> +	struct usb_endpoint_descriptor *epirq;
> +	unsigned int pipe;
> +	int retval;
> +
> +	/* Set up the endpoint information */
> +	/* This device only has an interrupt endpoint */
> +	retval = usb_find_common_endpoints(pxrc->intf->cur_altsetting,
> +			NULL, NULL, &epirq, NULL);
> +	if (retval) {
> +		dev_err(&pxrc->intf->dev,
> +			"Could not find endpoint\n");
> +		goto error;
> +	}
> +
> +	pxrc->bsize = usb_endpoint_maxp(epirq);
> +	pxrc->epaddr = epirq->bEndpointAddress;
> +	pxrc->data = devm_kmalloc(&pxrc->intf->dev, pxrc->bsize, GFP_KERNEL);
> +	if (!pxrc->data) {
> +		retval = -ENOMEM;
> +		goto error;
> +	}
> +
> +	usb_set_intfdata(pxrc->intf, pxrc);
> +	usb_make_path(pxrc->udev, pxrc->phys, sizeof(pxrc->phys));
> +	strlcat(pxrc->phys, "/input0", sizeof(pxrc->phys));
> +
> +	pxrc->urb = usb_alloc_urb(0, GFP_KERNEL);
> +	if (!pxrc->urb) {
> +		retval = -ENOMEM;
> +		goto error;
> +	}
> +
> +	pipe = usb_rcvintpipe(pxrc->udev, pxrc->epaddr),
> +	usb_fill_int_urb(pxrc->urb, pxrc->udev, pipe, pxrc->data, pxrc->bsize,
> +						pxrc_usb_irq, pxrc, 1);
> +
> +error:
> +	return retval;
> +
> +
> +}
> +
> +
> +static int pxrc_input_init(struct pxrc *pxrc)
> +{
> +	pxrc->input = devm_input_allocate_device(&pxrc->intf->dev);
> +	if (pxrc->input == NULL) {
> +		dev_err(&pxrc->intf->dev, "couldn't allocate input device\n");
> +		return -ENOMEM;
> +	}
> +
> +	pxrc->input->name = "PXRC Flight Controller Adapter";
> +	pxrc->input->phys = pxrc->phys;
> +	usb_to_input_id(pxrc->udev, &pxrc->input->id);
> +
> +	pxrc->input->open = pxrc_open;
> +	pxrc->input->close = pxrc_close;
> +
> +	input_set_capability(pxrc->input, EV_KEY, BTN_A);
> +	input_set_abs_params(pxrc->input, ABS_X, 0, 255, 0, 0);
> +	input_set_abs_params(pxrc->input, ABS_Y, 0, 255, 0, 0);
> +	input_set_abs_params(pxrc->input, ABS_RX, 0, 255, 0, 0);
> +	input_set_abs_params(pxrc->input, ABS_RY, 0, 255, 0, 0);
> +	input_set_abs_params(pxrc->input, ABS_RUDDER, 0, 255, 0, 0);
> +	input_set_abs_params(pxrc->input, ABS_THROTTLE, 0, 255, 0, 0);
> +	input_set_abs_params(pxrc->input, ABS_MISC, 0, 255, 0, 0);
> +
> +	input_set_drvdata(pxrc->input, pxrc);
> +
> +	return input_register_device(pxrc->input);
> +}
> +
> +static int pxrc_probe(struct usb_interface *intf,
> +		      const struct usb_device_id *id)
> +{
> +	struct pxrc *pxrc;
> +	int retval;
> +
> +	pxrc = devm_kzalloc(&intf->dev, sizeof(*pxrc), GFP_KERNEL);
> +
> +	if (!pxrc)
> +		return -ENOMEM;
> +
> +	pxrc->udev = usb_get_dev(interface_to_usbdev(intf));
> +	pxrc->intf = intf;
> +
> +	retval = pxrc_usb_init(pxrc);
> +	if (retval)
> +		goto error;
> +
> +	retval = pxrc_input_init(pxrc);
> +	if (retval)
> +		goto err_free_urb;
> +
> +	return 0;
> +
> +err_free_urb:
> +	usb_free_urb(pxrc->urb);
> +
> +error:
> +	return retval;
> +}
> +
> +static void pxrc_disconnect(struct usb_interface *intf)
> +{
> +	struct pxrc *pxrc = usb_get_intfdata(intf);
> +
> +	usb_free_urb(pxrc->urb);
> +	usb_set_intfdata(intf, NULL);
> +}
> +
> +static int pxrc_suspend(struct usb_interface *intf, pm_message_t message)
> +{
> +	struct pxrc *pxrc = usb_get_intfdata(intf);
> +	struct input_dev *input_dev = pxrc->input;
> +
> +	mutex_lock(&input_dev->mutex);
> +	usb_kill_urb(pxrc->urb);
> +	mutex_unlock(&input_dev->mutex);
> +
> +	return 0;
> +}
> +
> +static int pxrc_resume(struct usb_interface *intf)
> +{
> +	struct pxrc *pxrc = usb_get_intfdata(intf);
> +	struct input_dev *input_dev = pxrc->input;
> +	int retval = 0;
> +
> +	mutex_lock(&input_dev->mutex);
> +
> +	if (input_dev->users && usb_submit_urb(pxrc->urb, GFP_NOIO) < 0)
> +		retval = -EIO;
> +
> +	mutex_unlock(&input_dev->mutex);
> +
> +	return retval;
> +}
> +
> +static int pxrc_pre_reset(struct usb_interface *intf)
> +{
> +	struct pxrc *pxrc = usb_get_intfdata(intf);
> +	struct input_dev *input_dev = pxrc->input;
> +
> +	mutex_lock(&input_dev->mutex);
> +	usb_kill_urb(pxrc->urb);
> +
> +	return 0;
> +}
> +
> +static int pxrc_post_reset(struct usb_interface *intf)
> +{
> +	struct pxrc *pxrc = usb_get_intfdata(intf);
> +	struct input_dev *input_dev = pxrc->input;
> +	int retval = 0;
> +
> +	if (input_dev->users && usb_submit_urb(pxrc->urb, GFP_NOIO) < 0)
> +		retval = -EIO;
> +
> +	mutex_unlock(&input_dev->mutex);
> +
> +	return retval;
> +}
> +
> +static int pxrc_reset_resume(struct usb_interface *intf)
> +{
> +	return pxrc_resume(intf);
> +}
> +
> +static struct usb_driver pxrc_driver = {
> +	.name =		"pxrc",
> +	.probe =	pxrc_probe,
> +	.disconnect =	pxrc_disconnect,
> +	.id_table =	pxrc_table,
> +	.suspend	= pxrc_suspend,
> +	.resume		= pxrc_resume,
> +	.pre_reset	= pxrc_pre_reset,
> +	.post_reset	= pxrc_post_reset,
> +	.reset_resume	= pxrc_reset_resume,
> +	.supports_autosuspend = 1,
> +};
> +
> +module_usb_driver(pxrc_driver);
> +
> +MODULE_AUTHOR("Marcus Folkesson <marcus.folkesson@...il.com>");
> +MODULE_DESCRIPTION("PhoenixRC Flight Controller Adapter");
> +MODULE_LICENSE("GPL v2");
> -- 
> 2.15.1
> 

Thank you.

-- 
Dmitry

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