Message-ID: <96b01241-d57d-a460-4a8b-9e83eaab24ae@linaro.org>
Date:   Fri, 17 Mar 2023 09:54:07 +0100
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Subject: Re: [PATCH v2 1/7] dt-bindings: misc: Add the Lantiq PEF2466 E1/T1/J1
 framer
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To:     Herve Codina <herve.codina@bootlin.com>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Mark Brown <broonie@kernel.org>,
        Derek Kiernan <derek.kiernan@xilinx.com>,
        Dragan Cvetic <dragan.cvetic@xilinx.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.com>
Cc:     linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
        alsa-devel@alsa-project.org,
        Christophe Leroy <christophe.leroy@csgroup.eu>,
        Thomas Petazzoni <thomas.petazzoni@bootlin.com>
References: <20230316122741.577663-1-herve.codina@bootlin.com>
 <20230316122741.577663-2-herve.codina@bootlin.com>
From:   Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
In-Reply-To: <20230316122741.577663-2-herve.codina@bootlin.com>
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Precedence: bulk

On 16/03/2023 13:27, Herve Codina wrote:
> The Lantiq PEF2256 is a framer and line interface component designed to
> fulfill all required interfacing between an analog E1/T1/J1 line and the
> digital PCM system highway/H.100 bus.
> 
> Signed-off-by: Herve Codina <herve.codina@bootlin.com>
> ---
>  .../bindings/misc/lantiq,pef2256.yaml         | 190 ++++++++++++++++++
>  1 file changed, 190 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/misc/lantiq,pef2256.yaml
> 
> diff --git a/Documentation/devicetree/bindings/misc/lantiq,pef2256.yaml b/Documentation/devicetree/bindings/misc/lantiq,pef2256.yaml
> new file mode 100644
> index 000000000000..1ba788d06a14
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/misc/lantiq,pef2256.yaml
> @@ -0,0 +1,190 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/misc/lantiq,pef2256.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Lantiq PEF2256
> +
> +maintainers:
> +  - Herve Codina <herve.codina@bootlin.com>
> +
> +description:
> +  The Lantiq PEF2256, also known as Infineon PEF2256 or FALC256, is a framer and
> +  line interface component designed to fulfill all required interfacing between
> +  an analog E1/T1/J1 line and the digital PCM system highway/H.100 bus.
> +
> +properties:
> +  compatible:
> +    const: lantiq,pef2256
> +
> +  reg:
> +    maxItems: 1
> +
> +  clocks:
> +    items:
> +      - description: Master clock
> +
> +  clock-names:
> +    items:
> +      - const: mclk
> +
> +  interrupts:
> +    maxItems: 1
> +
> +  reset-gpios:
> +    description:
> +      GPIO used to reset the device.
> +    maxItems: 1
> +
> +  pinctrl:
> +    allOf:
> +      - $ref: "/schemas/pinctrl/pinctrl.yaml#"

Drop quotes. Drop allOf, no need for it.

additionalProperties: false

> +
> +    patternProperties:
> +      '-pins$':
> +        type: object
> +        allOf:
> +          - $ref: "/schemas/pinctrl/pincfg-node.yaml#"

Drop quotes. Drop allOf, no need for it.

additionalProperties: false


> +
> +        properties:
> +          pins:
> +            enum: [ RPA, RPB, RPC, RPD, XPA, XPB, XPC, XPD ]
> +
> +          function:
> +            enum: [ SYPR, RFM, RFMB, RSIGM, RSIG, DLR, FREEZE, RFSP, LOS,
> +                    SYPX, XFMS, XSIG, TCLK, XMFB, XSIGM, DLX, XCLK, XLT,
> +                    GPI, GPOH, GPOL ]
> +
> +        required:
> +          - pins
> +          - function
> +
> +  lantiq,line-interface:
> +    $ref: /schemas/types.yaml#/definitions/string
> +    enum: [e1, t1j1]
> +    default: e1
> +    description: |
> +      The line interface type
> +        - e1: E1 line
> +        - t1j1: T1/J1 line
> +
> +  lantiq,sysclk-rate-hz:
> +    enum: [2048000, 4096000, 8192000, 16384000]
> +    default: 2048000
> +    description:
> +      Clock rate (Hz) on the system highway.

I am pretty sure we have discussions on sysclk for other drivers. First,
why you cannot use assigned-clock-rates? Or clk_get_rate() if this is
about being consumer?

Second, there is already system-clock-frequency property, so use it.

> +
> +  lantiq,data-rate-bps:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    enum: [2048000, 4096000, 8192000, 16384000]
> +    default: 2048000
> +    description:
> +      Data rate (bit per seconds) on the system highway.

Why do you need it? How is it different from clock? Do you expect some
DDR here?

> +
> +  lantiq,clock-falling-edge:
> +    $ref: /schemas/types.yaml#/definitions/flag
> +    description:
> +      Data is sent on falling edge of the clock (and received on the rising
> +      edge). If 'clock-falling-edge' is not present, data is sent on the
> +      rising edge (and received on the falling edge).
> +
> +  lantiq,channel-phase:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    enum: [0, 1, 2, 3, 4, 5, 6, 7]
> +    default: 0
> +    description:
> +      The pef2256 delivers a full frame (32 8bit time-slots in E1 and 24 8bit
> +      time-slots 8 8bit signaling in E1/J1) every 125us. This lead to a data
> +      rate of 2048000 bit/s. When lantiq,data-rate-bps is more than 2048000
> +      bit/s, the data (all 32 8bit) present in the frame are interleave with
> +      unused time-slots. The lantiq,channel-phase property allows to set the
> +      correct alignment of the interleave mechanism.
> +      For instance, suppose lantiq,data-rate-bps = 8192000 (ie 4*2048000), and
> +      lantiq,channel-phase = 2, the interleave schema with unused time-slots
> +      (nu) and used time-slots (XX) for TSi is
> +        nu nu XX nu nu nu XX nu nu nu XX nu
> +        <-- TSi --> <- TSi+1 -> <- TSi+2 ->
> +      With lantiq,data-rate-bps = 8192000, and lantiq,channel-phase = 1, the
> +      interleave schema is
> +        nu XX nu nu nu XX nu nu nu XX nu nu
> +        <-- TSi --> <- TSi+1 -> <- TSi+2 ->
> +      With lantiq,data-rate-bps = 4096000 (ie 2*2048000), and
> +      lantiq,channel-phase = 1, the interleave schema is
> +        nu    XX    nu    XX    nu    XX
> +        <-- TSi --> <- TSi+1 -> <- TSi+2 ->
> +
> +  lantiq,subordinate:
> +    $ref: /schemas/types.yaml#/definitions/flag
> +    description:
> +      If present, the pef2256 works in subordinate mode. In this mode it
> +      synchronizes on line interface clock signals. Otherwise, it synchronizes
> +      on internal clocks.
> +
> +allOf:
> +  - if:
> +      properties:
> +        lantiq,line-interface:
> +          contains:
> +            const: e1
> +    then:
> +      properties:
> +        lantiq,frame-format:

Do not define properties in if:then, but in top-level. Disallow them or
customize for the specific cases in if:then

> +          $ref: /schemas/types.yaml#/definitions/string
> +          enum: [doubleframe, crc4-multiframe, auto-multiframe]
> +          default: doubleframe
> +          description: |
> +            The E1 line interface frame format
> +              - doubleframe: Doubleframe format
> +              - crc4-multiframe: CRC4 multiframe format
> +              - auto-multiframe: CRC4 multiframe format with interworking
> +                                 capabilities (ITU-T G.706 Annex B)
> +
> +    else:
> +      # T1/J1 line
> +      properties:
> +        lantiq,frame-format:

Same problem - definitions go to top level.

> +          $ref: /schemas/types.yaml#/definitions/string
> +          enum: [4frame, 12frame, 24frame, 72frame]
> +          default: 12frame
> +          description: |
> +            The T1/J1 line interface frame format
> +              - 4frame: 4-frame multiframe format (F4)
> +              - 12frame: 12-frame multiframe format (F12, D3/4)
> +              - 24frame: 24-frame multiframe format (ESF)
> +              - 72frame: 72-frame multiframe format (F72, remote switch mode)
> +
> +required:
> +  - compatible
> +  - reg
> +  - clocks
> +  - clock-names
> +  - interrupts
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/gpio/gpio.h>
> +    pef2256@2000000 {

Figure out some generic node name.

> +      compatible = "lantiq,pef2256";
> +      reg = <0x2000000 0xFF>;

Lowercase hex

> +      interrupts = <8 1>;

if 1 is interrupt flag, use proper defines.

> +      interrupt-parent = <&PIC>;
> +      clocks = <&clk_mclk>;
> +      clock-names = "mclk";
> +      reset-gpios = <&gpio 11 GPIO_ACTIVE_LOW>;
> +      lantiq,sysclk-rate-hz = <8192000>;
> +      lantiq,data-rate-bps = <4096000>;
> +
> +      pinctrl {
> +        pef2256_rpa_sypr: rpa-pins {
> +          pins = "RPA";
> +          function = "SYPR";
> +        };
> +        pef2256_xpa_sypx: xpa-pins {
> +          pins = "XPA";
> +          function = "SYPX";
> +        };
> +      };
> +    };

Best regards,
Krzysztof