Re: [alsa-devel] [PATCH linux-next v2 9/9] ASoC: rsnd: add busif property to dai stream

From: Kuninori Morimoto
Date: Tue Oct 09 2018 - 03:47:22 EST



Hi Jiada

Thanks for your feedback

> 1ch:  (tdm_slots < 4) Basic mode, (tdm_slots >= 4) TDM Split mode
> 2ch: (2 <= tdm_slots < 8) Basic mode, (tdm_slots >= 8) TDM Ex-Split mode
> 4ch: (4 <= tdm_slots < 8) Basic mode, (tdm_slots >= 8) TDM Ex-Split mode
> 6ch: (6 <= tdm_slots < 8) Basic mode, (tdm_slots == 8) TDM Extended
> mode, (8 < tdm_slots) TDM Ex-Split mode
> 8ch: (6 <= tdm_slots < 8) TDM Extended mode, (8 <= tdm_slots < 16)
> Basic mode, (tdm_slots == 16) TDM Ex-Split
> 10ch: TDM Ex-Split mode
> 16ch: Basic Mode

Sorry, but I couldn't understand what this table means ?
For example, what does "1ch" mean ?
It looks like "1ch playback by TDM"...

> The reason I added rsnd_ssi_select_busif(io, chan) in rsnd_hw_params()
> in patch ASoC: rsnd: add busif property to dai stream of v2 patch-set,
> is because runtime channel is necessary information to determine which
> BUSIFx to select,
> (which is mentioned in above)
> and at this stage (rsnd_hw_params()), all other control settings
> (register setting, dma address calculation etc)
> haven't been done, so corresponding dai-link can be considered to be
> not active at this timing
> but maybe you have better suggestion when to automatically select BUSIFx

My image is like this.

sound {
compatible = "simple-scu-audio-card or new card";
...
simple-audio-card,convert-channels = <8>;
...
busif0: simple-audio-card,cpu@0 { sound-dai = <&rcar_sound 0>; };
busif1: simple-audio-card,cpu@1 { sound-dai = <&rcar_sound 1>; };
busif2: simple-audio-card,cpu@2 { sound-dai = <&rcar_sound 2>; };
busif3: simple-audio-card,cpu@3 { sound-dai = <&rcar_sound 3>; };
simple-audio-card,codec { sound-dai = <&xxx>; };
};

rcar_sound {
dai0 { playback = <&ssiu0 ssi0>; }
dai1 { playback = <&ssiu1 ssi0>; }
dai2 { playback = <&ssiu2 ssi0>; }
dai3 { playback = <&ssiu3 ssi0>; }
};

Best regards
---
Kuninori Morimoto