51 lines
2.1 KiB
Plaintext
51 lines
2.1 KiB
Plaintext
NXP Audio Mixer (AUDMIX).
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The Audio Mixer is a on-chip functional module that allows mixing of two
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audio streams into a single audio stream. Audio Mixer has two input serial
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audio interfaces. These are driven by two Synchronous Audio interface
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modules (SAI). Each input serial interface carries 8 audio channels in its
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frame in TDM manner. Mixer mixes audio samples of corresponding channels
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from two interfaces into a single sample. Before mixing, audio samples of
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two inputs can be attenuated based on configuration. The output of the
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Audio Mixer is also a serial audio interface. Like input interfaces it has
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the same TDM frame format. This output is used to drive the serial DAC TDM
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interface of audio codec and also sent to the external pins along with the
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receive path of normal audio SAI module for readback by the CPU.
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The output of Audio Mixer can be selected from any of the three streams
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- serial audio input 1
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- serial audio input 2
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- mixed audio
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Mixing operation is independent of audio sample rate but the two audio
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input streams must have same audio sample rate with same number of channels
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in TDM frame to be eligible for mixing.
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Device driver required properties:
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=================================
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- compatible : Compatible list, contains "fsl,imx8qm-audmix"
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- reg : Offset and length of the register set for the device.
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- clocks : Must contain an entry for each entry in clock-names.
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- clock-names : Must include the "ipg" for register access.
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- power-domains : Must contain the phandle to AUDMIX power domain node
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- dais : Must contain a list of phandles to AUDMIX connected
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DAIs. The current implementation requires two phandles
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to SAI interfaces to be provided, the first SAI in the
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list being used to route the AUDMIX output.
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Device driver configuration example:
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======================================
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audmix: audmix@59840000 {
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compatible = "fsl,imx8qm-audmix";
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reg = <0x0 0x59840000 0x0 0x10000>;
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clocks = <&clk IMX8QXP_AUD_AUDMIX_IPG>;
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clock-names = "ipg";
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power-domains = <&pd_audmix>;
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dais = <&sai4>, <&sai5>;
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};
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