Input: Break out MT data

Move all MT-related things to a separate place. This saves some
bytes for non-mt input devices, and prepares for new MT features.

Reviewed-and-tested-by: Benjamin Tissoires <benjamin.tissoires@enac.fr>
Tested-by: Ping Cheng <pingc@wacom.com>
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
Input: Improve the events-per-packet estimate

The events-per-packet estimate has so far been used by MT devices
only. This patch adjusts the packet buffer size to also accomodate the
KEY and MSC events.  Keyboards normally send one or two keys at a
time. MT devices normally send a number of button keys along with the
MT information.  The buffer size chosen here covers those cases, and
matches the default buffer size in evdev. Since the input estimate is
now preferred, remove the special input-mt estimate.

Reviewed-and-tested-by: Ping Cheng <pingc@wacom.com>
Tested-by: Benjamin Tissoires <benjamin.tissoires@enac.fr>
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
Input: Make sure we follow all EV_KEY events

For some EV_KEY types, sending a larger-than-one value causes the
input state to oscillate. This patch makes sure this cannot happen,
clearing up the autorepeat bypass logic in the process.

Tested-by: Benjamin Tissoires <benjamin.tissoires@enac.fr>
Tested-by: Ping Cheng <pingc@wacom.com>
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
Input: Move autorepeat to the event-passing phase

Preparing to split event filtering and event passing, move the
autorepeat function to the point where the event is actually passed.

Tested-by: Benjamin Tissoires <benjamin.tissoires@enac.fr>
Tested-by: Ping Cheng <pingc@wacom.com>
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
Input: Send events one packet at a time

On heavy event loads, such as a multitouch driver, the irqsoff latency
can be as high as 250 us.  By accumulating a frame worth of data
before passing it on, the latency can be dramatically reduced.  As a
side effect, the special EV_SYN handling can be removed, since the
frame is now atomic.

This patch adds the events() handler callback and uses it if it
exists. The latency is improved by 50 us even without the callback.

Cc: Daniel Kurtz <djkurtz@chromium.org>
Tested-by: Benjamin Tissoires <benjamin.tissoires@enac.fr>
Tested-by: Ping Cheng <pingc@wacom.com>
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
Input: evdev - Add the events() callback

By sending a full frame of events at the same time, the irqsoff
latency at heavy load is brought down from 200 us to 100 us.

Cc: Daniel Kurtz <djkurtz@chromium.org>
Tested-by: Benjamin Tissoires <benjamin.tissoires@enac.fr>
Tested-by: Ping Cheng <pingc@wacom.com>
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
Input: MT - Add flags to input_mt_init_slots()

Preparing to move more repeated code into the mt core, add a flags
argument to the input_mt_slots_init() function.

Reviewed-and-tested-by: Benjamin Tissoires <benjamin.tissoires@enac.fr>
Tested-by: Ping Cheng <pingc@wacom.com>
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
Input: MT - Handle frame synchronization in core

Most MT drivers perform the same actions on frame synchronization.
Some actions, like dropping unseen contacts, are also unnecessarily
complex. Collect common frame synchronization tasks in a new function,
input_mt_sync_frame(). Depending on the flags set, it drops unseen
contacts and performs pointer emulation.

With init flags and frame synchronization in place, most MT drivers
can be simplified. First out are the bcm5974 and hid-multitouch
drivers, following this patch.

Reviewed-and-tested-by: Benjamin Tissoires <benjamin.tissoires@enac.fr>
Tested-by: Ping Cheng <pingc@wacom.com>
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
Input: MT - Add in-kernel tracking

With the INPUT_MT_TRACK flag set, the function input_mt_assign_slots()
can be used to match a new set of contacts against the currently used
slots. The algorithm used is based on Lagrange relaxation, and performs
very well in practice; slower than mtdev for a few corner cases, but
faster in most commonly occuring cases.

Tested-by: Benjamin Tissoires <benjamin.tissoires@enac.fr>
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
Input: MT - Get slot by key

Some devices use an internal key for tracking which cannot be directly
mapped to slots. This patch provides a key-to-slot mapping, which can
be used by drivers of such devices.

Reviewed-and-tested-by: Benjamin Tissoires <benjamin.tissoires@enac.fr>
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
Input: bcm5974 - only setup button urb for TYPE1 devices

The early generations with this trackpad used the separate mouse
interface to produce button events. With the introduction of the
button pads, this information was moved to the trackpad interface,
leaving the mouse interface unused. The driver is still setting up
both interfaces, which has not caused any problems - until now.

It turns out that without the CONFIG_USB_EHCI_TT_NEWSCHED option, the
driver may return an ENOSPC upon bt_urb submission, resulting in a
failure to open the device. This happens everytime on the MacBookPro
Retina (and likely on other mid-2012 models), but earlier MacBook
models seem to work fine.

This patch skips the bt_urb setup for TYPE2 devices, which arguably
should have been done in the first place.

Tested-by: Benjamin Tissoires <benjamin.tissoires@enac.fr>
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
Input: bcm5974 - Preparatory renames

Rename touch properties to match established nomenclature, and define
the maximum number of fingers.

Tested-by: Benjamin Tissoires <benjamin.tissoires@enac.fr>
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
Input: bcm5974 - Drop pressure and width emulation

The ABS_PRESSURE and ABS_WIDTH have special scales, and were initially
added solely for thumb and palm recognition in the synaptics driver.
This never really get used, however, and userspace quickly moved to
MT solutions instead. This patch drops the unused events.

Tested-by: Benjamin Tissoires <benjamin.tissoires@enac.fr>
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
Input: bcm5974 - Drop the logical dimensions

The logical scale was previously used to produce special width values
to userspace, and its only present use is to put "pressure" hysteresis
on a common scale. However, bcm5974 trackpads are very accurate and
work well without hysteresis.

This patch simplifies the driver and device data by removing the logical
scale altogether. While at it, the fake pressure range is replaced by the
orientation range, which will be used in a subsequent patch.

Tested-by: Benjamin Tissoires <benjamin.tissoires@enac.fr>
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
Input: bcm5974 - Convert to MT-B

Use of the in-kernel tracking code to convert the driver to MT-B.

With ten fingers on the pad, the in-kernel tracking adds approximately
25 us to the maximum irqsoff latency. Under normal workloads, however,
the tracking has no measurable effect.

Tested-by: Benjamin Tissoires <benjamin.tissoires@enac.fr>
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
HID: Add an input configured notification callback

A hid device may create several input devices, and a driver may need
to prepare or finalize the configuration per input device. Currently,
there is no sane way for a driver to know when a device has been
configured. This patch adds a callback providing that information.

Reviewed-and-tested-by: Benjamin Tissoires <benjamin.tissoires@enac.fr>
Tested-by: Ping Cheng <pingc@wacom.com>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
HID: hid-multitouch: Simplify setup and frame synchronization

With the input_configured() callback in place, the setup and frame
synchronization can be simplified. The input device initialization is
moved to mt_input_configured(), to make sure the full HID report has been
seen.

Reviewed-and-tested-by: Benjamin Tissoires <benjamin.tissoires@enac.fr>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
HID: hid-multitouch: Remove the redundant touch state

With the input_mt_sync_frame() function in place, there is no longer
any need to keep the full touch state in the driver. This patch
removes the slot state and replaces the lookup code with the input-mt
equivalent.

Reviewed-and-tested-by: Benjamin Tissoires <benjamin.tissoires@enac.fr>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
HID: hid-multitouch: Fix contact count on 3M panels

Some devices report the number of contacts via the unreliable
CONTACTCOUNT usage, rather than using the CONTACTMAX feature.
Without this patch, the 3M devices are constrained to the default
maximum of ten fingers.

Cc: Benjamin Tissoires <benjamin.tissoires@enac.fr>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
HID: Allow more fields in the hid report

Some recent hardware define more than 128 fields in the report
descriptor. Increase the limit to 256. This adds another kilobyte of
memory per report.

Tested-by: Ping Cheng <pingc@wacom.com>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>