Question about daifmt of legacy DT on simple-card

[Kuninori Morimoto]

Hi ALSA SoC
Cc Jyri

For historical reason, simple-card supports legacy DT daifmt
settings. Then, I noticed one strange code.

	-- simple-card-utils.c ---

	asoc_simple_parse_daifmt(xxx)
	{
(A)		daifmt = snd_soc_of_parse_daifmt(...);
		daifmt &= ~SND_SOC_DAIFMT_MASTER_MASK;

		if (!bitclkmaster && !framemaster) {
			/*
			 * No dai-link level and master setting was not found from
			 * sound node level, revert back to legacy DT parsing and
			 * take the settings from codec node.
			 */
(B)			daifmt = snd_soc_of_parse_daifmt(codec, NULL, NULL, NULL) |
				(daifmt & ~SND_SOC_DAIFMT_CLOCK_MASK);
		} ...
		...
	}

It rollbacks to legacy DT parsing at (B) if (A) didn't have
master settings.
Here, (B) re-try to get daifmt, and use "or" with (daifmt & ~CLOCK mask).
Why CLOCK mask ? and shouldn't it use mask when "or" ?
Otherwise FORMAT and INV part will be duplicated, I think.
for example
	daifmt = (snd_soc_of_parse_daifmt() &  SND_SOC_DAIFMT_CLOCK_MASK) |
		 (daifmt                    & ~SND_SOC_DAIFMT_CLOCK_MASK)

I think using snd_soc_of_parse_daifmt() only is very enough at (B),
but am I misunderstanding ??

The original code was from

	b3ca11ff59bc5842b01f13421a17e6d9a8936784
	("ASoC: simple-card: Move dai-link level properties away from dai subnodes")

Thank you for your help !!

Best regards
---
Kuninori Morimoto