iio: core: add IIO_VAL_DECIMAL64_FEMTO format type

Extend the IIO_VAL_DECIMAL64_* family with a femto-scaled variant
(scale 15), following the existing MILLI/MICRO/NANO/PICO pattern. Both
the read formatting path in __iio_format_value() and the write parsing
path in iio_write_channel_info() (via kstrtodec64()) already derive
their scale from "type - IIO_VAL_DECIMAL64_BASE", so the new type only
needs to be added to the respective switch cases.

This is needed by drivers reporting very small SI quantities where the
existing pico scale loses precision. For example the Sensirion SLF3S
liquid flow sensor reports its volume-flow scale in m^3/s, where the
SLF3S-0600F scale is ~1.667e-12 m^3/s: at pico scale only a single
significant digit survives, whereas femto scale preserves the full
sensor resolution.

Signed-off-by: Wadim Mueller <wafgo01@gmail.com>
Reviewed-by: Rodrigo Alencar <rodrigo.alencar@analog.com>
Signed-off-by: Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>

0 files changed, 0 insertions, 0 deletions