[PATCH v5 0/9] Output raw touch data via V4L2

[Nick Dyer]

This is a series of patches to add output of raw touch diagnostic data via V4L2
to the Atmel maXTouch and Synaptics RMI4 drivers.

It's a rewrite of the previous implementation which output via debugfs: it now
uses a V4L2 device in a similar way to the sur40 driver.

We have a utility which can read the data and display it in a useful format:
    https://github.com/ndyer/heatmap/commits/heatmap-v4l

These patches are also available from
    https://github.com/ndyer/linux/commits/v4l-touch-2016-06-22

Changes in v5 (Hans Verkuil review):
- Update v4l2-core:
  - Add VFL_TYPE_TOUCH, V4L2_BUF_TYPE_TOUCH_CAPTURE and V4L2_CAP_TOUCH
  - Change V4L2_INPUT_TYPE_TOUCH_SENSOR to V4L2_INPUT_TYPE_TOUCH
  - Improve DocBook documentation
  - Add FMT definitions for touch data
  - Note this will need the latest version of the heatmap util
- Synaptics RMI4 driver:
  - Remove some less important non full frame report types
  - Switch report type names to const char * array
  - Move a static array to inside context struct
- Split sur40 changes to a separate commit

Changes in v4:
- Address nits from the input side in atmel_mxt_ts patches (Dmitry Torokhov)
- Add Synaptics RMI4 F54 support patch

Changes in v3:
- Address V4L2 review comments from Hans Verkuil
- Run v4l-compliance and fix all issues - needs minor patch here:
  https://github.com/ndyer/v4l-utils/commit/cf50469773f

Changes in v2:
- Split pixfmt changes into separate commit and add DocBook
- Introduce VFL_TYPE_TOUCH_SENSOR and /dev/v4l-touch
- Remove "single node" support for now, it may be better to treat it as
  metadata later
- Explicitly set VFL_DIR_RX
- Fix Kconfig