tools: topology1: imx8ulp: correct BCLK rate and change BCLK polarity and protocol #8978
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LaurentiuM1234
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kv2019i
dbaluta
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Mar 22, 2024
plbossart
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Mar 22, 2024
Rename the `RATE` parameter to `FSYNC_RATE` in order to remove ambiguity regarding what the parameter is. Signed-off-by: Laurentiu Mihalcea <laurentiu.mihalcea@nxp.com>
8ULP has two supported BT HFP scenarios: NBS and WBS. For NBS the frequency of FSYNC is 8k, while for WBS the frequency of FSYNC is 16k. Since the BCLK is computed as: Freq(BCLK) = TDM_SLOTS * TDM_SLOT_WIDTH * Freq(FSYNC) then that means we're going to end up with two different BCLK frequencies (one for each supported scenario). Currently, what we do is pass the frequency of FSYNC as a build argument, while keeping the frequency of BCLK constant (set to 256000, which would be the same value as the one used in WBS). This causes the following issues: 1) The Zephyr native SAI driver returns an error when trying to commit the configuration because the frequency of BCLK doesn't abide by the aforementioned formula. 2) We end up consuming twice as many samples in a given unit of time. To fix these issues, use the aforementioned formula to compute the frequency of BCLK. Signed-off-by: Laurentiu Mihalcea <laurentiu.mihalcea@nxp.com>
The BT codec used by the IW416 chip expects FSYNC to be asserted for only one BCLK. Also, FSYNC should be active HIGH. As such, change from I2S protocol to DSP_A protocol since the configurations made for this protocol inside the SAI driver are more suited. Also, by default, the BT codec drives data on BCLK rising edge and samples it on falling edge. With the DSP_A protocol, the SAI driver also has the same configuration, which is wrong since we can't drive and sample on the same edge and cycle. As such, invert BCLK polarity such that the SAI will drive on rising edge and sample on falling edge. Signed-off-by: Laurentiu Mihalcea <laurentiu.mihalcea@nxp.com>
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iuliana-prodan
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These patches are needed for the native transition. Trying to upstream them before the transition itself to make the PR doing the transition easier to review.