On 18/12/2023 13:40, Elinor Montmasson wrote:
Hello,
This is the v3 of the series of patch aiming to make the machine driver "fsl-asoc-card" compatible with use cases where there is no real codec driver. It proposes to use the "spdif_receiver" and "spdif_transmitter" drivers instead of the dummy codec. This is a first step in using the S/PDIF controller with the ASRC.
The five first patches add compatibility with the pair of codecs "spdif_receiver" and "spdif_transmitter" with a new compatible, "fsl,imx-audio-generic". Codec parameters are set with default values. Consequently, the driver is modified to work with multi-codec use cases. It can get 2 codecs phandles from the device tree, and the "fsl_asoc_card_priv" struct now has 2 "codec_priv" to store properties of both codecs. It is fixed to 2 codecs as only "fsl,imx-audio-generic" uses multiple codecs at the moment. However, the driver now uses for_each_codecs macros when possible to ease future implementations of multi-codec configurations.
The remaining patches add configuration options for the device tree. They configure the CPU DAI when using "fsl,imx-audio-generic". These options are usually hard-coded in "fsl-asoc-card.c" for each audio codec. Because the generic codec could be used with other CPU DAIs than the S/PDIF controller, setting these parameters could be required.
This series of patch was successfully built for arm64 and x86 on top of the latest for-next branch of the ASoC git tree on the 14th of December. These modifications have also been tested on an i.MX8MN evaluation board, with a linux kernel RT v6.1.26-rt8.
We also have a few questions, following remarks made by Krzysztof Kozlowski in a previous email for patch 10/10:
The compatible list for this generic sound card currently: @@ -48,6 +51,8 @@ The compatible list for this generic sound card currently:
"fsl,imx-audio-nau8822"
- "fsl,imx-audio-generic"
Generic does not look like hardware specific.
Even if our end goal is to use it with the S/PDIF controller, this new support can be used with different hardware that doesn't require a codec. Thus, we don't really want to specify "spdif" in it.
Is this compatible string not suitable ? Should we rename it to something else, like "fsl,imx-audio-no-codec" ?
Maybe Mark or Rob will help here, but for me "imx-audio" is just way too generic.
- Which generic name should we use ? Or how should we change it?
Compatible should be specific to one SoC, even if there is one driver for entire family.
Also, you add several new properties, so I really expect either converting old binding to DT schema first or adding new device in DT schema format.
- fsl-asoc-card.txt currently follows the old dt-bindings format.
Should we update it to DT schema format in this patch series before adding my new properties?
You add six new properties, so from my point of view this cannot be in TXT.
Best regards, Krzysztof