This adds support for the ADAQ7767-1, ADAQ7768-1 and ADAQ7769-1 devices. 

The ADAQ7768-1 and ADAQ7769-1 integrate a programmable gain amplifier (PGA)
with 7 and 8 gain options, respectively. The ADAQ7767-1 and ADAQ7769-1 
also feature a 3-pin selectable Anti-aliasing filter (AAF) gain.

---
Changes in v3:
* Renamed adi,gain-milli to adi,aaf-gain-bp. Now it represents basis points
  (one hundredth of a percent).
* ad7768_channel_masks removed along with available_masks element in
  ad7768_chip_info struct. It does not add anything for single channels,
  so not needed, at least for now.
* New patch adding 64-bit fractional number types to math.h.
* Moved aaf gain parsing to its own function, and now returning after
  warning to avoid setting a variable when it shouldn't (avoid confusion).
* ad7768_set_pga_gain(): removed the pgia enable check, relying on the
  regmap cache.
* Addressed other review comments, see individual patches.

Changes in v2:
* adi,aaf-gain property renamed to adi,gain-milli. Default value added.
* fixed some commit messages. 
* Added 'select RATIONAL' to Kconfig.
* Added lock to protect PGA value access.
* rewrote AAF gain check and replaced error returns with warnings.
* Addressed other review comments, see individual patches.
* Link to v1: https://lore.kernel.org/linux-iio/cover.1754617360.git.Jonathan.Santos@analog.com/T/#t
---
Jonathan Santos (4):
  dt-bindings: iio: adc: ad7768-1: add new supported parts
  iio: adc: ad7768-1: introduce chip info for future multidevice support
  math.h: Add 64-bit fractional numbers types
  iio: adc: ad7768-1: add support for ADAQ776x-1 ADC Family

 .../bindings/iio/adc/adi,ad7768-1.yaml        |  44 ++-
 drivers/iio/adc/Kconfig                       |   1 +
 drivers/iio/adc/ad7768-1.c                    | 359 ++++++++++++++++--
 include/linux/math.h                          |   2 +
 4 files changed, 377 insertions(+), 29 deletions(-)


base-commit: 91812d3843409c235f336f32f1c37ddc790f1e03
-- 
2.34.1