iio: make stm32 trigger driver use INDIO_HARDWARE_TRIGGERED mode

Add validate function to be use to use the correct trigger.
Add an attribute to configure device mode like for quadrature and
enable modes

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2 files changed