linux-kernel - Re: [PATCH v4 11/23] ASoC: simple-card: Loop over all children for 'mclk-fs'

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Date:   Tue, 30 Jun 2020 09:53:13 +0530
From:   Sameer Pujar <spujar@...dia.com>
To:     Kuninori Morimoto <kuninori.morimoto.gx@...esas.com>
CC:     <spujar@...dia.com>, <broonie@...nel.org>, <perex@...ex.cz>,
        <tiwai@...e.com>, <robh+dt@...nel.org>, <lgirdwood@...il.com>,
        <thierry.reding@...il.com>, <jonathanh@...dia.com>,
        <digetx@...il.com>, <alsa-devel@...a-project.org>,
        <linux-tegra@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <sharadg@...dia.com>, <mkumard@...dia.com>,
        <viswanathl@...dia.com>, <rlokhande@...dia.com>,
        <dramesh@...dia.com>, <atalambedu@...dia.com>,
        <nwartikar@...dia.com>, <swarren@...dia.com>,
        <nicoleotsuka@...il.com>
Subject: Re: [PATCH v4 11/23] ASoC: simple-card: Loop over all children for
 'mclk-fs'



On 6/30/2020 7:38 AM, Kuninori Morimoto wrote:
> External email: Use caution opening links or attachments
>
>
> Hi Sameer
>
>>>>         snprintf(prop, sizeof(prop), "%smclk-fs", prefix);
>>>>         of_property_read_u32(node,      prop, &props->mclk_fs);
>>>>         of_property_read_u32(cpu,       prop, &props->mclk_fs);
>>>> -     of_property_read_u32(codec,     prop, &props->mclk_fs);
>>>> +
>>>> +     if (cpu != codec)
>>>> +             of_property_read_u32(codec, prop, &props->mclk_fs);
>>> Maybe we want to have "cpu" in simple_dai_link_of_dpcm() side
>>> without using magical code in simple_parse_mclk_fs() side ?
>> Are you suggesting if we should simplify simple_parse_mclk_fs() by
>> either passing 'cpu' or 'codec'?
> Oops, sorry I was misunderstand.
>
> But I still not 100% understand what do you want to do here.
> Maybe 50% is my English skill, but in your code
>
> (C)             of_property_read_u32(cpu,       prop, &props->mclk_fs);
>          -       of_property_read_u32(codec,     prop, &props->mclk_fs);
>          +
>          +       if (cpu != codec)
> (B)     +               of_property_read_u32(codec, prop, &props->mclk_fs);
>
> and
>
>          -       simple_parse_mclk_fs(top, np, codec, dai_props, prefix);
> (A)     +       simple_parse_mclk_fs(top, np, np, dai_props, prefix);
>
> Because of (A), cpu = codec = np in simple_parse_mclk_fs().
> Do we have chance to call (B) ?
> And it still have read_u32(cpu, ...) at (C),
> this means all np will read mclk_fs anyway ?
> For me, if you don't want/need mclk_fs, don't set it on DT
> is the best answer, but am I misunderstanding ?
Sorry if I was not clear before.

My goal was to get rid of 'codec' argument from DPCM function 
simple_dai_link_of_dpcm(). Patches 10/23, 11/23 are preparations for 
12/23 to have multiple Codec support.

simple_parse_mclk_fs() is used by both simple_dai_link_of_dpcm() and 
simple_dai_link_of(). To make the same API work for both the cases, I 
had to use (A) in DPCM function. Now (B) does not get used for 
simple_dai_link_of_dpcm(), but will get used by simple_dai_link_of().

If it is simpler I will just avoid 'cpu != codec' check and keep the 
function simple_parse_mclk_fs() as it is.

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