linux-kernel - Re: [PATCH v2 1/3] ASoC: hdmi-codec: Add event handler for hdmi TX

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Message-ID: <Y4Y/vEWe3dw0FPQH@sirena.org.uk>
Date:   Tue, 29 Nov 2022 17:22:04 +0000
From:   Mark Brown <broonie@...nel.org>
To:     Jiaxin Yu (俞家鑫) <Jiaxin.Yu@...iatek.com>
Cc:     "linux-mediatek@...ts.infradead.org" 
        <linux-mediatek@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Chunxu Li (李春旭) <Chunxu.Li@...iatek.com>,
        "ajye_huang@...pal.corp-partner.google.com" 
        <ajye_huang@...pal.corp-partner.google.com>,
        Allen-KH Cheng (程冠勳) 
        <Allen-KH.Cheng@...iatek.com>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        "kuninori.morimoto.gx@...esas.com" <kuninori.morimoto.gx@...esas.com>,
        "andrzej.hajda@...el.com" <andrzej.hajda@...el.com>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        Project_Global_Chrome_Upstream_Group 
        <Project_Global_Chrome_Upstream_Group@...iatek.com>,
        "robert.foss@...aro.org" <robert.foss@...aro.org>,
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        <Laurent.pinchart@...asonboard.com>,
        "neil.armstrong@...aro.org" <neil.armstrong@...aro.org>,
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        <angelogioacchino.delregno@...labora.com>,
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        "alsa-devel@...a-project.org" <alsa-devel@...a-project.org>
Subject: Re: [PATCH v2 1/3] ASoC: hdmi-codec: Add event handler for hdmi TX

On Mon, Nov 28, 2022 at 03:07:22PM +0000, Jiaxin Yu (俞家鑫) wrote:
> On Fri, 2022-11-25 at 12:18 +0000, Mark Brown wrote:
> > On Fri, Nov 25, 2022 at 05:44:11PM +0800, Jiaxin Yu wrote:

> > I'm a little unclear why this is being implemented as a DAPM
> > operation
> > rather than having the driver forward the PCM trigger op if it's
> > needed?
> > Or alternatively if a DAPM callback is needed why not provide one
> > directly rather than hooking into the trigger function - that's going
> > to
> > be called out of sequence with the rest of DAPM and be potentially
> > confusing given the very different environments that trigger and DAPM
> > operations run in.  A quick glance at the it6505 driver suggests it'd
> > be
> > happier with a DAPM callback.

> Let me describe the hardware connection about mt8186 with it6505(hdmi)
> and rt1015p(speakers).

>                        ==>it6505 
>                      = 
> DL1(FE) ==>I2S3(BE) =
>                      =
>                        ==>rt1015p

> They shared the same one i2s port, but we'd like to control them
> separately. So if hdmi-codec use the PCM trigger op, whne we turn on
> the speaker, hdmi-codec's PCM trigger op is also executed, resulting in
> sound on both devices.
> Is there another way to control them separately? Thank you.

If you just need power control for one or both devices then the machine
driver can add a _PIN_SWITCH() on the output of the device, that'll
cause DAPM to keep the device powered down when not in use.  That should
work well with the suggestion to provide a DAPM callback instead of a a
trigger operation.

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