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Date:   Wed, 13 Sep 2023 09:26:40 +0200
From:   Herve Codina <herve.codina@bootlin.com>
To:     Conor Dooley <conor@kernel.org>
Cc:     "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>, Andrew Lunn <andrew@lunn.ch>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>, Lee Jones <lee@kernel.org>,
        Linus Walleij <linus.walleij@linaro.org>,
        Qiang Zhao <qiang.zhao@nxp.com>, Li Yang <leoyang.li@nxp.com>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Mark Brown <broonie@kernel.org>,
        Jaroslav Kysela <perex@perex.cz>,
        Takashi Iwai <tiwai@suse.com>,
        Shengjiu Wang <shengjiu.wang@gmail.com>,
        Xiubo Li <Xiubo.Lee@gmail.com>,
        Fabio Estevam <festevam@gmail.com>,
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        Christophe Leroy <christophe.leroy@csgroup.eu>,
        Randy Dunlap <rdunlap@infradead.org>, netdev@vger.kernel.org,
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        Simon Horman <horms@kernel.org>,
        Christophe JAILLET <christophe.jaillet@wanadoo.fr>,
        Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Subject: Re: [PATCH v5 08/31] dt-bindings: soc: fsl: cpm_qe: cpm1-scc-qmc:
 Add support for QMC HDLC
Message-ID: <20230913092640.76934b31@bootlin.com>
In-Reply-To: <20230912-capable-stash-c7a3e33078ac@spud>
References: <20230912081527.208499-1-herve.codina@bootlin.com>
        <20230912101018.225246-1-herve.codina@bootlin.com>
        <20230912-capable-stash-c7a3e33078ac@spud>
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Hi Conor,

On Tue, 12 Sep 2023 18:21:58 +0100
Conor Dooley <conor@kernel.org> wrote:

> On Tue, Sep 12, 2023 at 12:10:18PM +0200, Herve Codina wrote:
> > The QMC (QUICC mutichannel controller) is a controller present in some
> > PowerQUICC SoC such as MPC885.
> > The QMC HDLC uses the QMC controller to transfer HDLC data.
> >=20
> > Additionally, a framer can be connected to the QMC HDLC.
> > If present, this framer is the interface between the TDM bus used by the
> > QMC HDLC and the E1/T1 line.
> > The QMC HDLC can use this framer to get information about the E1/T1 line
> > and configure the E1/T1 line.
> >=20
> > Signed-off-by: Herve Codina <herve.codina@bootlin.com>
> > ---
> >  .../bindings/soc/fsl/cpm_qe/fsl,cpm1-scc-qmc.yaml   | 13 +++++++++++++
> >  1 file changed, 13 insertions(+)
> >=20
> > diff --git a/Documentation/devicetree/bindings/soc/fsl/cpm_qe/fsl,cpm1-=
scc-qmc.yaml b/Documentation/devicetree/bindings/soc/fsl/cpm_qe/fsl,cpm1-sc=
c-qmc.yaml
> > index 82d9beb48e00..b5073531f3f1 100644
> > --- a/Documentation/devicetree/bindings/soc/fsl/cpm_qe/fsl,cpm1-scc-qmc=
.yaml
> > +++ b/Documentation/devicetree/bindings/soc/fsl/cpm_qe/fsl,cpm1-scc-qmc=
.yaml
> > @@ -101,6 +101,16 @@ patternProperties:
> >            Channel assigned Rx time-slots within the Rx time-slots rout=
ed by the
> >            TSA to this cell.
> > =20
> > +      compatible:
> > +        const: fsl,qmc-hdlc
> > +
> > +      fsl,framer:
> > +        $ref: /schemas/types.yaml#/definitions/phandle
> > +        description:
> > +          phandle to the framer node. The framer is in charge of an E1=
/T1 line
> > +          interface connected to the TDM bus. It can be used to get th=
e E1/T1 line
> > +          status such as link up/down. =20
>=20
> Sounds like this fsl,framer property should depend on the compatible
> being present, no?

Well from the implementation point of view, only the QMC HDLC driver uses t=
his
property.

=46rom the hardware description point of view, this property means that the t=
ime slots
handled by this channel are connected to the framer. So I think it makes se=
nse for
any channel no matter the compatible (even if compatible is not present).

Should I change and constraint the fsl,framer property to the compatible pr=
esence ?
If so, is the following correct for this contraint ?
   --- 8< ---
   dependencies:
     - fsl,framer: [ compatible ];
   --- 8< ---

Regards,
Herv=C3=A9

>=20
> Thanks,
> Conor.
>=20
> > +
> >      required:
> >        - reg
> >        - fsl,tx-ts-mask
> > @@ -159,5 +169,8 @@ examples:
> >              fsl,operational-mode =3D "hdlc";
> >              fsl,tx-ts-mask =3D <0x00000000 0x0000ff00>;
> >              fsl,rx-ts-mask =3D <0x00000000 0x0000ff00>;
> > +
> > +            compatible =3D "fsl,qmc-hdlc";
> > +            fsl,framer =3D <&framer>;
> >          };
> >      };
> > --=20
> > 2.41.0
> >  =20