Date:   Tue, 31 Jan 2023 08:45:08 +0100
From:   Herve Codina <herve.codina@bootlin.com>
To:     Rob Herring <robh@kernel.org>
Cc:     Li Yang <leoyang.li@nxp.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Mark Brown <broonie@kernel.org>,
        Christophe Leroy <christophe.leroy@csgroup.eu>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Nicholas Piggin <npiggin@gmail.com>,
        Qiang Zhao <qiang.zhao@nxp.com>,
        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>,
        Nicolin Chen <nicoleotsuka@gmail.com>,
        linuxppc-dev@lists.ozlabs.org,
        linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, alsa-devel@alsa-project.org,
        Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Subject: Re: [PATCH v4 05/10] dt-bindings: soc: fsl: cpm_qe: Add QMC
 controller
Message-ID: <20230131084508.32b80a1b@bootlin.com>
In-Reply-To: <20230130183037.GA3076426-robh@kernel.org>
References: <20230126083222.374243-1-herve.codina@bootlin.com>
        <20230126083222.374243-6-herve.codina@bootlin.com>
        <20230130183037.GA3076426-robh@kernel.org>
Organization: Bootlin
MIME-Version: 1.0
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Precedence: bulk

Hi Rob,

On Mon, 30 Jan 2023 12:30:37 -0600
Rob Herring <robh@kernel.org> wrote:

> On Thu, Jan 26, 2023 at 09:32:17AM +0100, Herve Codina wrote:
> > Add support for the QMC (QUICC Multichannel Controller)
> > available in some PowerQUICC SoC such as MPC885 or MPC866.
> >=20
> > Signed-off-by: Herve Codina <herve.codina@bootlin.com>
> > ---
> >  .../bindings/soc/fsl/cpm_qe/fsl,qmc.yaml      | 167 ++++++++++++++++++=
 =20
>=20
> fsl,cpm1-scc-qmc.yaml

Ok, will be changed in the next iteration.

>=20
> >  1 file changed, 167 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/soc/fsl/cpm_qe/fs=
l,qmc.yaml
> >=20
> > diff --git a/Documentation/devicetree/bindings/soc/fsl/cpm_qe/fsl,qmc.y=
aml b/Documentation/devicetree/bindings/soc/fsl/cpm_qe/fsl,qmc.yaml
> > new file mode 100644
> > index 000000000000..9141a8ca183b
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/soc/fsl/cpm_qe/fsl,qmc.yaml
> > @@ -0,0 +1,167 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/soc/fsl/cpm_qe/fsl,qmc.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: PowerQUICC CPM QUICC Multichannel Controller (QMC)
> > +
> > +maintainers:
> > +  - Herve Codina <herve.codina@bootlin.com>
> > +
> > +description:
> > +  The QMC (QUICC Multichannel Controller) emulates up to 64 channels w=
ithin one
> > +  serial controller using the same TDM physical interface routed from =
TSA.
> > +
> > +properties:
> > +  compatible:
> > +    items:
> > +      - enum:
> > +          - fsl,mpc885-scc-qmc
> > +          - fsl,mpc866-scc-qmc
> > +      - const: fsl,cpm1-scc-qmc
> > +
> > +  reg:
> > +    items:
> > +      - description: SCC (Serial communication controller) register ba=
se
> > +      - description: SCC parameter ram base
> > +      - description: Dual port ram base
> > +
> > +  reg-names:
> > +    items:
> > +      - const: scc_regs
> > +      - const: scc_pram
> > +      - const: dpram
> > +
> > +  interrupts:
> > +    maxItems: 1
> > +    description: SCC interrupt line in the CPM interrupt controller
> > +
> > +  fsl,tsa-serial:
> > +    $ref: /schemas/types.yaml#/definitions/phandle-array
> > +    items:
> > +      - items:
> > +          - description: phandle to TSA node
> > +          - enum: [1, 2, 3]
> > +            description: |
> > +              TSA serial interface (dt-bindings/soc/fsl,tsa.h defines =
these
> > +              values)
> > +               - 1: SCC2
> > +               - 2: SCC3
> > +               - 3: SCC4
> > +    description:
> > +      Should be a phandle/number pair. The phandle to TSA node and the=
 TSA
> > +      serial interface to use.
> > +
> > +  '#address-cells':
> > +    const: 1
> > +
> > +  '#size-cells':
> > +    const: 0
> > +
> > +  '#chan-cells':
> > +    const: 1 =20
>=20
> What's this?

A QMC consumer, such as "QMC audio" in this series, can have a phandle with
an argument that points to this QMC node. For instance, in the "QMC audio"
node, we have:
  fsl,qmc-chan =3D <&qmc 16>;

The #chan-cells property in TSA specify the presence of this argument.

What do you think if I add the following description:
   '#chan-cells':
     const: 1
     description:
       QMC consumers that use a phandle to QMC need to pass the channel
       number with this phandle.
       For instance "fsl,qmc-chan =3D <&qmc 16>;".

>=20
> > +
> > +patternProperties:
> > +  '^channel@([0-9]|[1-5][0-9]|6[0-3])$':
> > +    description:
> > +      A channel managed by this controller
> > +    type: object
> > +
> > +    properties:
> > +      reg:
> > +        minimum: 0
> > +        maximum: 63
> > +        description:
> > +          The channel number
> > +
> > +      fsl,operational-mode:
> > +        $ref: /schemas/types.yaml#/definitions/string
> > +        enum: [transparent, hdlc]
> > +        default: transparent
> > +        description: |
> > +          The channel operational mode
> > +            - hdlc: The channel handles HDLC frames
> > +            - transparent: The channel handles raw data without any pr=
ocessing
> > +
> > +      fsl,reverse-data:
> > +        $ref: /schemas/types.yaml#/definitions/flag
> > +        description:
> > +          The bit order as seen on the channels is reversed,
> > +          transmitting/receiving the MSB of each octet first.
> > +          This flag is used only in 'transparent' mode.
> > +
> > +      fsl,tx-ts-mask:
> > +        $ref: /schemas/types.yaml#/definitions/uint64
> > +        description:
> > +          Channel assigned Tx time-slots within the Tx time-slots rout=
ed by the
> > +          TSA to this cell.
> > +
> > +      fsl,rx-ts-mask:
> > +        $ref: /schemas/types.yaml#/definitions/uint64
> > +        description:
> > +          Channel assigned Rx time-slots within the Rx time-slots rout=
ed by the
> > +          TSA to this cell.
> > +
> > +    required:
> > +      - reg
> > +      - fsl,tx-ts-mask
> > +      - fsl,rx-ts-mask
> > +
> > +required:
> > +  - compatible
> > +  - reg
> > +  - reg-names
> > +  - interrupts
> > +  - fsl,tsa-serial
> > +  - '#address-cells'
> > +  - '#size-cells'
> > +  - '#chan-cells'
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > +  - |
> > +    #include <dt-bindings/soc/fsl,tsa.h>
> > +
> > +    qmc@a60 {
> > +        compatible =3D "fsl,mpc885-scc-qmc", "fsl,cpm1-scc-qmc";
> > +        reg =3D <0xa60 0x20>,
> > +              <0x3f00 0xc0>,
> > +              <0x2000 0x1000>;
> > +        reg-names =3D "scc_regs", "scc_pram", "dpram";
> > +        interrupts =3D <27>;
> > +        interrupt-parent =3D <&CPM_PIC>;
> > +
> > +        #address-cells =3D <1>;
> > +        #size-cells =3D <0>;
> > +        #chan-cells =3D <1>;
> > +
> > +        fsl,tsa-serial =3D <&tsa FSL_CPM_TSA_SCC4>;
> > +
> > +        channel@16 {
> > +            /* Ch16 : First 4 even TS from all routed from TSA */
> > +            reg =3D <16>;
> > +            fsl,mode =3D "transparent";
> > +            fsl,reverse-data;
> > +            fsl,tx-ts-mask =3D <0x00000000 0x000000aa>;
> > +            fsl,rx-ts-mask =3D <0x00000000 0x000000aa>;
> > +        };
> > +
> > +        channel@17 {
> > +            /* Ch17 : First 4 odd TS from all routed from TSA */
> > +            reg =3D <17>;
> > +            fsl,mode =3D "transparent";
> > +            fsl,reverse-data;
> > +            fsl,tx-ts-mask =3D <0x00000000 0x00000055>;
> > +            fsl,rx-ts-mask =3D <0x00000000 0x00000055>;
> > +        };
> > +
> > +        channel@19 {
> > +            /* Ch19 : 8 TS (TS 8..15) from all routed from TSA */
> > +            reg =3D <19>;
> > +            fsl,mode =3D "hdlc";
> > +            fsl,tx-ts-mask =3D <0x00000000 0x0000ff00>;
> > +            fsl,rx-ts-mask =3D <0x00000000 0x0000ff00>;
> > +        };
> > +    };
> > --=20
> > 2.39.0
> >  =20

Thanks for the review,
Herv=C3=A9

--=20
Herv=C3=A9 Codina, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com