linux-kernel - Re: [PATCH v3 7/7] ASoC: dt-bindings: mediatek,mt8188-afe: add audio properties

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Date:   Fri, 5 May 2023 07:31:44 +0000
From:   Trevor Wu (吳文良) <Trevor.Wu@...iatek.com>
To:     "robh@...nel.org" <robh@...nel.org>
CC:     "linux-mediatek@...ts.infradead.org" 
        <linux-mediatek@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "broonie@...nel.org" <broonie@...nel.org>,
        "tiwai@...e.com" <tiwai@...e.com>,
        "lgirdwood@...il.com" <lgirdwood@...il.com>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "krzysztof.kozlowski+dt@...aro.org" 
        <krzysztof.kozlowski+dt@...aro.org>,
        "matthias.bgg@...il.com" <matthias.bgg@...il.com>,
        "perex@...ex.cz" <perex@...ex.cz>,
        "alsa-devel@...a-project.org" <alsa-devel@...a-project.org>,
        "angelogioacchino.delregno@...labora.com" 
        <angelogioacchino.delregno@...labora.com>
Subject: Re: [PATCH v3 7/7] ASoC: dt-bindings: mediatek,mt8188-afe: add audio
 properties

On Thu, 2023-04-27 at 09:48 -0500, Rob Herring wrote:
> External email : Please do not click links or open attachments until
> you have verified the sender or the content.
> 
> 
> On Wed, Apr 26, 2023 at 01:51:24PM +0800, Trevor Wu wrote:
> > Add apll1_d4 to clocks for switching the parent of top_a1sys_hp
> > dynamically. On the other hand, "mediatek,infracfg" is included for
> > bus
> > protection.
> 
> Bus protection? Meaning access controls for the device? If so,
> there's a
> proposed binding[1] for just that. If that's something Mediatek needs
> too, please participate in that discussion. It's easier to define new
> common bindings if there is more than one user.
> 

Hi Rob,

Bus protection is a function used to prevent from the unexpected glitch
during the reset. The suggested reset control flow is listed as below.

bus protection on
module reset
bus protection off

I think it is not the same as access control of the device. In
addition, no framework or controller was implemented for MTK bus
protection. Here, I just make use of the property to get the phandle of
infracfg to access the register for bus protection.

> > 
> > Signed-off-by: Trevor Wu <trevor.wu@...iatek.com>
> > ---
> >  .../bindings/sound/mediatek,mt8188-afe.yaml          | 12
> > ++++++++++--
> >  1 file changed, 10 insertions(+), 2 deletions(-)
> > 
> > diff --git
> > a/Documentation/devicetree/bindings/sound/mediatek,mt8188-afe.yaml
> > b/Documentation/devicetree/bindings/sound/mediatek,mt8188-afe.yaml
> > index 82ccb32f08f2..eb58de8c0e68 100644
> > --- a/Documentation/devicetree/bindings/sound/mediatek,mt8188-
> > afe.yaml
> > +++ b/Documentation/devicetree/bindings/sound/mediatek,mt8188-
> > afe.yaml
> > @@ -29,6 +29,10 @@ properties:
> >      $ref: /schemas/types.yaml#/definitions/phandle
> >      description: The phandle of the mediatek topckgen controller
> > 
> > +  mediatek,infracfg:
> > +    $ref: /schemas/types.yaml#/definitions/phandle
> > +    description: The phandle of the mediatek infracfg controller
> > +
> >    power-domains:
> >      maxItems: 1
> > 
> > @@ -52,6 +56,7 @@ properties:
> >        - description: mux for i2si1_mck
> >        - description: mux for i2si2_mck
> >        - description: audio 26m clock
> > +      - description: audio pll1 divide 4
> > 
> >    clock-names:
> >      items:
> > @@ -73,6 +78,7 @@ properties:
> >        - const: i2si1_m_sel
> >        - const: i2si2_m_sel
> >        - const: adsp_audio_26m
> > +      - const: apll1_d4
> 
> A new required entry may break the ABI. If that's okay, it needs to
> be
> explained in the commit msg.
> 

It should be OK, because the project is still developing and there is
no device tree file for mt8188 upstream. I will add the reason to the
message in v4.

Sorry, I didn't notice that before. I will review my future work and
check if any required property or item should be included to the
binding before mt8188 audio device tree upstream.

Thanks,
Trevor

> Rob
> 
> [1] 
> https://lore.kernel.org/lkml/cover.1668070216.git.oleksii_moisieiev@epam.com/