HID: elo: Revert USB reference counting

Commit 817b8b9c539 ("HID: elo: fix memory leak in elo_probe") introduced
memory leak on error path, but more importantly the whole USB reference
counting is not needed at all in the first place, as the driver itself
doesn't change the reference counting in any way, and the associated
usb_device is guaranteed to be kept around by USB core as long as the
driver binding exists.

Reported-by: Alan Stern <stern@rowland.harvard.edu>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: fbf42729d0e ("HID: elo: update the reference count of the usb device structure")
Fixes: 817b8b9c539 ("HID: elo: fix memory leak in elo_probe")
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

HID: elo: fix memory leak in elo_probe

When hid_parse() in elo_probe() fails, it forgets to call usb_put_dev to
decrease the refcount.

Fix this by adding usb_put_dev() in the error handling code of elo_probe().

Fixes: fbf42729d0e9 ("HID: elo: update the reference count of the usb device structure")
Reported-by: syzkaller <syzkaller@googlegroups.com>
Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

HID: check for valid USB device for many HID drivers

Many HID drivers assume that the HID device assigned to them is a USB
device as that was the only way HID devices used to be able to be
created in Linux. However, with the additional ways that HID devices
can be created for many different bus types, that is no longer true, so
properly check that we have a USB device associated with the HID device
before allowing a driver that makes this assumption to claim it.

Cc: Jiri Kosina <jikos@kernel.org>
Cc: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Cc: Michael Zaidman <michael.zaidman@gmail.com>
Cc: Stefan Achatz <erazor_de@users.sourceforge.net>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@foss.st.com>
Cc: linux-input@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tested-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
[bentiss: amended for thrustmater.c hunk to apply]
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Link: https://lore.kernel.org/r/20211201183503.2373082-3-gregkh@linuxfoundation.org

HID: elo: update the reference count of the usb device structure

Use usb_get_dev() to increment the reference count of the usb device
structure in order to avoid releasing the structure while it is still in
use. And use usb_put_dev() to decrement the reference count and thus,
when it will be equal to 0 the structure will be released.

Signed-off-by: Salah Triki <salah.triki@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 307

Based on 1 normalized pattern(s):

this driver is licensed under the terms of gplv2

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 1 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Armijn Hemel <armijn@tjaldur.nl>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190530000434.051516995@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

HID: elo: clear BTN_LEFT mapping

ELO devices have one Button usage in GenDesk field, which makes hid-input map
it to BTN_LEFT; that confuses userspace, which then considers the device to be
a mouse/touchpad instead of touchscreen.

Fix that by unmapping BTN_LEFT and keeping only BTN_TOUCH in place.

Signed-off-by: Jiri Kosina <jkosina@suse.cz>

HID: elo: kill not flush the work

Flushing a work that reschedules itself is not a sensible operation. It needs
to be killed. Failure to do so leads to a kernel panic in the timer code.

CC: stable@vger.kernel.org
Signed-off-by: Oliver Neukum <ONeukum@suse.com>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

HID: hid-input: allow input_configured callback return errors

When configuring input device via input_configured callback we may
encounter errors (for example input_mt_init_slots() may fail). Instead
of continuing with half-initialized input device let's allow driver
indicate failures.

Signed-off-by: Jaikumar Ganesh <jaikumarg@android.com>
Signed-off-by: Arve Hjønnevåg <arve@android.com>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Nikolai Kondrashov <Nikolai.Kondrashov@redhat.com>
Acked-by: Andrew Duggan <aduggan@synaptics.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

HID: hid-input: allow input_configured callback return errors

When configuring input device via input_configured callback we may
encounter errors (for example input_mt_init_slots() may fail). Instead
of continuing with half-initialized input device let's allow driver
indicate failures.

Signed-off-by: Jaikumar Ganesh <jaikumarg@android.com>
Signed-off-by: Arve Hjønnevåg <arve@android.com>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Nikolai Kondrashov <Nikolai.Kondrashov@redhat.com>
Acked-by: Andrew Duggan <aduggan@synaptics.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

HID: hid-elo: some systems cannot stomach work around

Some systems although they have firmware class 'M', which usually
needs a work around to not crash, must not be subjected to the
work around because the work around crashes them. They cannot be
told apart by their own device descriptor, but as they are part
of compound devices, can be identified by looking at their siblings.

Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

HID: elo: add quirks for broken firmware

One firmare version in the devices the driver takes care of is
completely broken and needs periodic pokes from our side. We
implemented this as a periodic delayed queue. The idea of the pokes
was taken from the suse enterprise kernel, in particular from Libor's
"Elo touchscreen firmware M workaround".

I am quoting him here:
This patch adds periodic polling of the Elo USB touchscreens. Needed
as a workaround for devices with M-level firmware, otherwise these
devices are known to misbehave (as reported by Elo developers).

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Tested-by: Petr Ostadal <postadal@suse.cz>
Cc: Oliver Neukum <oliver@neukum.org>
Cc: Vojtech Pavlik <vojtech@suse.cz>
Cc: Egbert Eich <eich@suse.com>
Cc: Libor Pechacek <lpechacek@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

HID: add driver for ELO 4000/4500

This is a driver for ELO 4000/4500 devices which report themselves as
HID devices, but do not really send HID events on touch. So we
introduce a new HID 'quirk' driver with a raw_event handler where we
take care of those events.

What we need additionally is an input_configured hook, because the
device does not mention anything about PRESSURE and TOUCH in its
report descriptor, but it actually generate those. So we set the bits
in the corresponding input_dev in that hook.

Thanks to Petr Ostadal who was willing to test the driver. The rest of
Cc's listed below had something to do with that driver over the years
in our enterprise tree.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Tested-by: Petr Ostadal <postadal@suse.cz>
Cc: Oliver Neukum <oliver@neukum.org>
Cc: Vojtech Pavlik <vojtech@suse.cz>
Cc: Egbert Eich <eich@suse.com>
Cc: Libor Pechacek <lpechacek@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>