ASoC: dt-bindings: wm8904: Add DMIC, GPIO, MIC and EQ support

ASoC: dt-bindings: wm8904: Add DMIC, GPIO, MIC and EQ support

Add two properties to select the IN1L/DMICDAT1 and IN2R/DMICDAT2
functionality:
- wlf,in1l-as-dmicdat1
- wlf,in1r-as-dmicdat2

Add a property to describe the GPIO configuration registers, that can be
used to set the four multifunction pins:
- wlf,gpio-cfg

Add a property to describe the mic bias control registers:
- wlf,micbias-cfg

Add two properties to describe the Dynamic Range Controller (DRC),
allowing multiple named configurations where each config sets the 4 DRC
registers (R40-R43):
- wlf,drc-cfg-regs
- wlf,drc-cfg-names

Add three properties to describe the equalizer (ReTune Mobile), allowing
multiple named configurations (associated with a samplerate) that set
the 24 (R134-R157) EQ registers:
- wlf,retune-mobile-cfg-regs
- wlf,retune-mobile-cfg-hz
- wlf,retune-mobile-cfg-rates

The set of names and configurations for DRC and ReTune Mobile are
specified by system integrators. The names are exposed directly to
userspace as options that can be selected at runtime.

Adding the DRC and ReTune Mobile data to the DT eases the transition
from pdata, which has handled them this way for over a decade. The
parameters filled in here are almost certainly specific tuning for the
hardware so it makes sense to ship them with the hardware description.

Datasheet: https://statics.cirrus.com/pubs/proDatasheet/WM8904_Rev4.1.pdf
Signed-off-by: Ernest Van Hoecke <ernest.vanhoecke@toradex.com>
Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Reviewed-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://patch.msgid.link/20250319142059.46692-4-francesco@dolcini.it
Signed-off-by: Mark Brown <broonie@kernel.org>