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Implement SPDIF bypass mode. It implies internal SoC routing of SPDIF input signal to SPDIF output signal. The test bed requires two boards: B1 configured in bypass mode, and B2 to feed B1 SPDIF RX port and read B1 SPDIF TX port: B2 TX -> B1 RX, B2 RX <- B1 TX. The test procedure: a) Boot both boards b) B2: start "arecord <spdifcard> -r 48kHz | aplay <local DAC>" c) B2: start "aplay <spdifcard> -r 48kHz <2ch 48kHz audio file>" d) B1: enable bypass mode: amixer -cimxspdif cset numid=8,iface=PCM,name='Bypass Mode' on e) B2: check DAC audio, make sure the same sample rate is used at steps b) and c), in example above the rate is 48kHz. f) B1: try to run "aplay" or "arecord" on imxspdif card while in bypass mode - both must fail until bypass mode is disabled g) B1: disable bypass mode: amixer -cimxspdif cset numid=8,iface=PCM,name='Bypass Mode' off h) B1: check the usual playback and capture on imxspdif card. During this test try to set bypass mode - must not be allowed while playback or capture is running. Signed-off-by: Viorel Suman <viorel.suman@nxp.com> Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com> Link: https://lore.kernel.org/r/1632649760-1651-1-git-send-email-shengjiu.wang@nxp.com Signed-off-by: Mark Brown <broonie@kernel.org>
Linux kernel
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