Re: [PATCH 00/18] *** Implement simple haptic HID support ***

From: Roderick Colenbrander <thunderbird2k@gmail.com>
To: Angela Czubak <acz@semihalf.com>
Cc: linux-input <linux-input@vger.kernel.org>,
	upstream@semihalf.com,
	Dmitry Torokhov <dmitry.torokhov@gmail.com>
Subject: Re: [PATCH 00/18] *** Implement simple haptic HID support ***
Date: Wed, 22 Dec 2021 08:17:04 -0800	[thread overview]
Message-ID: <CAEc3jaD97Oq2uJ4g=5hOzHmOBCvyj2k=++cMSFGhvp8GBadedg@mail.gmail.com> (raw)
In-Reply-To: <20211221191743.1893185-1-acz@semihalf.com>

Hi Angela,

Thanks for sharing. I would like to have a look as well at this
series. As I briefly mentioned in another thread at Sony we have a
need for haptics as well for our DualSense controller for the
PlayStation 5. There is some overlap and differences. For our use
case, FF is really showing its limits (it really doesn't work). The
key question I have is whether FF is really a good fit for your use
case or not. I don't understand this type of device well enough yet.
There might be enough demand for either a new framework (or it is the
end of the road for evdev).

Thanks,
Roderick

On Wed, Dec 22, 2021 at 7:59 AM Angela Czubak <acz@semihalf.com> wrote:
>
> This patch series introduces changes necessary to support devices
> using simple haptic HID pages.
> Implementation attempts to follow the discussion below:
> https://www.spinics.net/lists/linux-input/msg61091.html
>
> Introduce new haptic defines as specified in HID Usage Tables.
>
> Add new force feedback effect type in order to facilitate using
> simple haptic force feedback.
>
> Add INPUT_PROP_HAPTIC_TOUCHPAD to mark touchpad exposing simple haptic
> support.
>
> Add new struct hid_haptic_device so as to gather simple haptic related
> configuration and current state of the device.
>
> Function mt_get_feature() gets renamed to hid_get_feature() and is moved
> to hid-core.c as it is not specific to hid multitouch driver and may be
> reused, for instance by simple haptic specific source.
>
> Add new functions to be triggered during HID input mapping and
> configuration in order to detect simple haptic devices.
>
> Modify HID input so that haptic output reports are parsed.
>
> Initialize a haptic device.
>
> Modify FF core so that effect IDs can be shared between multiple open file
> handles.
>
> Add shared release and press effects for a simple haptic device.
>
> Calculate pressure resolution if units are grams or newtons.
>
> Add support for kernel-driven mode of simple haptic device.
>
> Toggle ABS_PRESSURE generation by input-mt on request.
>
> Implement functions allowing switching between kernel-managed mode
> and autonomous mode.
>
> Add simple haptic support for hid-multitouch driver.
>
> Implement EVIOCFF(TAKE|RELEASE)CONTROL ioctls so that userspace can take
> and release control of shared release and press effects.
>
> Fix i2c_hid_set_or_send_report so that report IDs larger than 0xF are
> handled correctly.
>
> Angela Czubak (18):
>   HID: add haptics page defines
>   Input: add FF_HID effect type
>   Input: add INPUT_PROP_HAPTIC_TOUCHPAD
>   HID: haptic: introduce hid_haptic_device
>   HID: introduce hid_get_feature
>   HID: haptic: add functions for mapping and configuration
>   HID: input: allow mapping of haptic output
>   HID: haptic: initialize haptic device
>   Input: add shared effects
>   HID: haptic: implement release and press effects
>   HID: input: calculate resolution for pressure
>   HID: haptic: add functions handling events
>   Input: MT - toggle ABS_PRESSURE pointer emulation
>   HID: haptic: add hid_haptic_switch_mode
>   HID: multitouch: add haptic multitouch support
>   Input: introduce EVIOCFF(TAKE|RELEASE)CONTROL
>   HID: haptic: add hid_haptic_change_control
>   HID: i2c-hid: fix i2c_hid_set_or_send_report
>
>  drivers/hid/Kconfig                    |  15 +
>  drivers/hid/Makefile                   |   1 +
>  drivers/hid/hid-core.c                 |  39 ++
>  drivers/hid/hid-haptic.c               | 745 +++++++++++++++++++++++++
>  drivers/hid/hid-haptic.h               | 150 +++++
>  drivers/hid/hid-input.c                |  18 +-
>  drivers/hid/hid-multitouch.c           | 109 ++--
>  drivers/hid/i2c-hid/i2c-hid-core.c     |  12 +-
>  drivers/input/evdev.c                  |   6 +
>  drivers/input/ff-core.c                | 129 ++++-
>  drivers/input/input-mt.c               |  18 +-
>  include/linux/hid.h                    |  24 +
>  include/linux/input.h                  |   5 +
>  include/linux/input/mt.h               |   4 +
>  include/uapi/linux/input-event-codes.h |   1 +
>  include/uapi/linux/input.h             |  26 +-
>  16 files changed, 1247 insertions(+), 55 deletions(-)
>  create mode 100644 drivers/hid/hid-haptic.c
>  create mode 100644 drivers/hid/hid-haptic.h
>
> --
> 2.34.1.307.g9b7440fafd-goog
>