imx8mp SAI bit counter not working

Brian_B — Sun, 09 Nov 2025 01:24:37 GMT

I am working with the imx8mp processor, receiving serial data over SAI2. The SAI's VERID register indicates version 3.1 with timestamp registers. I have the SAI2 receive working and dumping the incoming data into a DMA buffer. The master clock, bit clock, and frame clock are all generated externally. I expected to get values in the timestamp counter (RTSR), bit counter (RBCR), and bit timestamp (RBCTR), but they stay at zero even as I am receiving valid data. I have verified via readback that the receive timestamp control (RTCR) is 0x000003, which should allow the timestamp counter to increment even without the bit counter incrementing. Is there anything else I need to configure to get the bit counter and timestamp working?

Re: imx8mp SAI bit counter not working

Brian_B — Sun, 09 Nov 2025 01:52:45 GMT

Never mind - apparently the regmap_read function I was using was reading back cached values. I switched to readl and now I am getting valid values.

Thanks anyway!

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imx8mp SAI bit counter not working

Re: imx8mp SAI bit counter not working