Hello,
Following some work to reduce the impact of audio resampling in Linux, we would like to use the ASRC of the i.MX8 SoCs with the S/PDIF controller. With that aim, this series of patch for the machine driver fsl-asoc-card proposes to add compatibility with the dummy codec driver. This is a first step in using the S/PDIF controller with the ASRC, as the imx-spdif machine driver uses the dummy codec with the fsl_spdif DAI driver.
The five first patches add compatibility with the dummy codec through a new compatible, fsl,imx-audio-dummy-codec. Codec parameters are set with default values.
The remaining patches add configuration options through device tree for the codec parameters that can also impact the CPU DAI. These are usually hard-coded in fsl-asoc-card for each audio codec. Because this dummy codec could be use with other CPU DAI than the S/PDIF controller, these could need specific configuration.
This series of patch was successfully built for arm64 and x86 on top of the latest for-next branch of the ASoC git tree at https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git/ on the 28/08. These modifications have also been tested on an i.MX8MN evaluation board, with a linux kernel RT v6.1.26-rt8.
Regards, Elinor Montmasson