[PATCH v2 0/3] Add PAT9125 optical tracker driver

[Alexandre Mergnat]

PixArt Imaging PAT9125 is a miniature low power optical navigation chip using
LASER light source enabling digital surface tracking.

This device driver use IIO API to provide ponctual and/or buffered data.
The data is the delta value between two position traveled, depend on
CPI (Counts Per Inch) resolution setting chosen. The retrived data is
composed by two values, delta on the X and Y axis.

The devece support configuration through module parameter interface.

This patchset :
- Update vendor prefix
- Add the bindings for this device
- Add the device driver
- Add directory for optical tracker devices

Change since v1:
- Fix typo
- Rename some defines / variables
- Remove I2C client from driver structure
- Change type of delta_x and delta_y from s16 to s32 to simplify signed operations
- Add module parameter for axis resolution
- Replace "IIO_MOD_X_AND_Y" by "IIO_MOD_X" and "IIO_MOD_Y"
- Add sign extention macro
- Improve read value algorithm to avoid data loss
- Implement a trigger handler function which can work with any IIO trigger, independently of it own GPIO IRQ, to match with IIO requirement / behavior
- Replace iio push event function by iio trigger poll in GPIO IRQ handler
- Use triggered_buffer helpers to replace kfifo use, setup buffer, implement enable/disable setup buffer operations, IIO trigger allocation and reenable operations
- Remove useless "goto"
- Change GPIO IRQ handler from planified thread to IRQ thread
- Change GPIO IRQ trigger from low level and one shot to falling edge
- Add device unregister and buffer cleanup to driver remove function

Alexandre Mergnat (3):
  dt-bindings: Add pixart vendor
  dt-bindings: iio: ot: Add docs pat9125
  iio: Add PAT9125 optical tracker sensor

 .../devicetree/bindings/iio/ot/pat9125.txt    |  18 +
 .../devicetree/bindings/vendor-prefixes.txt   |   1 +
 drivers/iio/Kconfig                           |   1 +
 drivers/iio/Makefile                          |   1 +
 drivers/iio/ot/Kconfig                        |  16 +
 drivers/iio/ot/Makefile                       |   6 +
 drivers/iio/ot/pat9125.c                      | 487 ++++++++++++++++++
 7 files changed, 530 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/ot/pat9125.txt
 create mode 100644 drivers/iio/ot/Kconfig
 create mode 100644 drivers/iio/ot/Makefile
 create mode 100644 drivers/iio/ot/pat9125.c

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2.17.1