Hi,
when the codec RST input is connected to a GPIO it needs to be pulled high in order to take the pcm3168a out from reset and to make it respond to register accesses via i2c.
I have a board where one GPIO line is connected to two pcm3168a codec so runtime handling of the RST gpio is not possible (one codec would place the other codec to reset as well).
The only possible solution is to request the gpio with GPIOD_FLAGS_BIT_NONEXCLUSIVE flag, ask it to be high initially and never touch it again.
If the optinal GPIO is not described then issue the reset as the driver did.
Regards, Peter --- Peter Ujfalusi (2): bindings: sound: pcm3168a: Document optional RST gpio ASoC: pcm3168a: Add support for optional RST gpio handling
.../devicetree/bindings/sound/ti,pcm3168a.txt | 7 ++++ sound/soc/codecs/pcm3168a.c | 38 +++++++++++++++++-- 2 files changed, 41 insertions(+), 4 deletions(-)