There are i2s signals provided in low-speed connector on such boards as required by 96boards spec. Looks like it is possible to actually playback something via these pins after adding missing parts here and there. I tested simple widely available cheap DACs like UDA1334 and PCM5102A and they works just fine without need for mclk. I guess any DAC that can handle 48 kHz and 16bit will do. In theory db845 can work without mezzanine board and this provides one more use-case to playback sound and not all mezzanines have cosy audio connectors. After staring at https://patchwork.kernel.org/project/linux-arm-kernel/patch/20210621074152.306362-1-judyhsiao@xxxxxxxxxxxx/ I suspect that this might not gonna fly since it requires dummy codec. Or maybe specific half-dummy qcom codec for such use-case is required to verify hw parameters. Couldn't say. Alexey Klimov (3): ASoC: qcom: common: set codecless link to be a backend ASoC: qcom: sdm845: add handling of secondary MI2S clock arm64: dts: qcom: sdm845-db845c: add i2s playback support via LS1 connector arch/arm64/boot/dts/qcom/sdm845-db845c.dts | 43 +++++++++++++++++++++- sound/soc/qcom/common.c | 4 ++ sound/soc/qcom/sdm845.c | 5 ++- 3 files changed, 48 insertions(+), 4 deletions(-) -- 2.45.2
