linux-kernel - Re: [PATCH v1 2/3] ASoC: rsnd: Allow reconfiguration of clock rate

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Date:   06 Aug 2019 17:05:52 +0900
From:   Kuninori Morimoto <kuninori.morimoto.gx@...esas.com>
To:     Jiada Wang <jiada_wang@...tor.com>
Cc:     <lgirdwood@...il.com>, <broonie@...nel.org>, <perex@...ex.cz>,
        <tiwai@...e.com>, <twischer@...adit-jv.com>,
        <alsa-devel@...a-project.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v1 2/3] ASoC: rsnd: Allow reconfiguration of clock rate


Hi Jiada

> > 2nd, can we keep usrcnt setup as-is ?
> > I guess we can just avoid rsnd_ssi_master_clk_start() if ssi->rate was not 0 ?
> 
> I don't fully understand your 2nd question,
> in case of rsnd_ssi_master_clk_stop(), if avoid
> rsnd_ssi_master_clk_stop() when ssi->rate is 0 by apply following
> change
> 
>  	static void rsnd_ssi_master_clk_stop(struct rsnd_mod *mod,
>  				     struct rsnd_dai_stream *io)
>  	{
>  		...
>  -		if (ssi->usrcnt > 1)
>  +		if (ssi->rate == 0)
>  			return;
>  		...
>  	}
> 
> then when any IO stream with same SSI calls .hw_free,
> the other IO stream's clock will be stopped too.

I think we can find more simple solution if we can find good ideas.
For example, how about to add new counter for hw_params/hw_free ?
Anyway, [3/3] patch is too much over-kill to me.

And, please don't exchange usrcnt inc/dec position at [2/3].
It is for open/close.

Thank you for your help !!
Best regards
---
Kuninori Morimoto