[PATCH v2 0/3] iio: cdc: add Texas Instruments FDC1004 driver

[Victor Chernyakin]

This series adds support for the FDC1004 4-channel I2C capacitive sensor.
This sensor can report single-ended measurements of any one of its
channels, as well as differential measurements between any pair
of them. It has a measurement range of +-15 pF and a resolution of 0.5 fF.

Patch 1 adds higher-precision IIO_VAL_DECIMAL64_* formats, used
in the driver.
Patch 2 adds the devicetree bindings.
Patch 3 adds the driver itself.

Tested with the sensor connected over an i2c-tiny-usb adapter.

---
Changes in v2:
- Patch 1
  - Added tests
  - Added a fix in iio_format_value
- Patch 2
  - Made the power supply mandatory
- Patch 3
  - Switched from direct I2C calls to regmap
  - Added of device table
  - Removed scan indexes
  - Build up complex values incrementally
  - Adjusted list of includes
  - More designed initializers
  - Various style/whitespace tweaks
- Link to v1: https://lore.kernel.org/SN1PR12MB25286BE4E1EA3B75F8E563A9A5652@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

---
Victor Chernyakin (3):
  iio: add IIO_VAL_DECIMAL64_{ATTO,ZEPTO,YOCTO} formats
  dt-bindings: iio: cdc: add Texas Instruments FDC1004
  iio: cdc: add Texas Instruments FDC1004 driver

 .../bindings/iio/cdc/ti,fdc1004.yaml          |  46 ++
 MAINTAINERS                                   |   6 +
 drivers/iio/cdc/Kconfig                       |  10 +
 drivers/iio/cdc/Makefile                      |   1 +
 drivers/iio/cdc/fdc1004.c                     | 486 ++++++++++++++++++
 drivers/iio/industrialio-core.c               |  28 +-
 drivers/iio/test/iio-test-format.c            |  16 +
 include/linux/iio/types.h                     |   3 +
 8 files changed, 592 insertions(+), 4 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/iio/cdc/ti,fdc1004.yaml
 create mode 100644 drivers/iio/cdc/fdc1004.c

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2.53.0