Re: [PATCH v3] input: pxrc: new driver for PhoenixRC Flight Controller Adapter
From: Marcus Folkesson
Date: Wed Jan 17 2018 - 08:59:01 EST
Hello Dmitry,
On Tue, Jan 16, 2018 at 03:16:25PM -0800, Dmitry Torokhov wrote:
> 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@xxxxxxxxx>
> > ---
> > 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.
The test I've done is simply reading from the input device and then call
`pm-suspend`.
It works, suspend is called and reset_resume() will submit the URB
again. Without the PM code, the application did not read any events upon
resume.
However, I found another tricky part.
If I enable autosuspend (as you suggest) it will suspend when noone is
using the device. Good.
But when someone is opening the device, input_dev->users is counted up
to 1 before resume() is called.
Is this intended?
This code (from resume()) will therefor allways submit the URB:
if (input_dev->users && usb_submit_urb(pxrc->urb, GFP_NOIO) < 0)
Then open() is called and fails because the urb is allready submitted.
input_dev->users is only incremented in input.c:input_open_device() what
I can tell?
I will move the submitting code to reset_resume() instead.
>
> > 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@xxxxxxxxx>
> > +
> > +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@xxxxxxxxx>
> > + *
> > + */
> > +
> > +#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.
>
Yes. Thank you.
> > + /* 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@xxxxxxxxx>");
> > +MODULE_DESCRIPTION("PhoenixRC Flight Controller Adapter");
> > +MODULE_LICENSE("GPL v2");
> > --
> > 2.15.1
> >
>
> Thank you.
>
> --
> Dmitry
Best regards
Marcus Folkesson