RE: [PATCH 3/6] dt-bindings: sound: Add sound card bindings for Tesla FSD

["Padmanabhan Rajanbabu" <p.rajanbabu@samsung.com>]

> -----Original Message-----
> From: Krzysztof Kozlowski [mailto:krzysztof.kozlowski@linaro.org]
> Sent: 22 October 2022 10:19 PM
> To: Padmanabhan Rajanbabu <p.rajanbabu@samsung.com>; 'Rob Herring'
> <robh@kernel.org>
> Cc: lgirdwood@gmail.com; broonie@kernel.org;
> krzysztof.kozlowski+dt@linaro.org; s.nawrocki@samsung.com;
> perex@perex.cz; tiwai@suse.com; pankaj.dubey@samsung.com;
> alim.akhtar@samsung.com; rcsekar@samsung.com;
> aswani.reddy@samsung.com; alsa-devel@alsa-project.org;
> devicetree@vger.kernel.org; linux-kernel@vger.kernel.org; linux-samsung-
> soc@vger.kernel.org
> Subject: Re: [PATCH 3/6] dt-bindings: sound: Add sound card bindings for
> Tesla FSD
> 
> On 21/10/2022 04:44, Padmanabhan Rajanbabu wrote:
> >> On Fri, Oct 14, 2022 at 03:51:48PM +0530, Padmanabhan Rajanbabu wrote:
> >>> Add dt-binding reference document to configure the DAI link for
> >>> Tesla FSD sound card driver.
> >>
> >> The simple-card or graph-card bindings don't work for you?
> > Thank you for reviewing the patch.
> >
> > The actual reason for having a custom sound card driver lies in the
> > fact that the Samsung i2s cpu dai requires configuration of some
> > Samsung specific properties like rfs, bfs, codec clock direction and
> > root clock source. We do not have flexibility of configuring the same
> > in simple card driver (sound/soc/generic/simple-card.c) or audio graph
> > card driver (sound/soc/generic/audio-graph-card.c). The binding has
> > been added to support the custom sound card driver.
> >
> > I understand from your query that the newly added card has device tree
> > nodes and properties which are used in simple card as well, but having
> > a different or new prefixes. I believe to address that, we can
> > restructure the string names to generic ones.
> 
> You must use generic, existing properties where applicable.

Okay

> 
> > But I would like to understand, to reuse the simple card or audio
> > graph card bindings, can we add secondary compatible strings in the
> > simple card dt-binding for the custom sound card to probe ?
> 
> If you see other vendor compatibles there, then yes... But there aren't any,
> right?

Yes you are right, we don't see other vendor compatibles. But, am I allowed
to add such secondary compatibles so that we can extend the simple card
and its utilities to a large extent?

If no, then I believe we will need a separate binding to extend the generic
properties.
> 
> >>
> >>>
> >>> Signed-off-by: Padmanabhan Rajanbabu <p.rajanbabu@samsung.com>
> >>> ---
> >>>  .../bindings/sound/tesla,fsd-card.yaml        | 158 ++++++++++++++++++
> >>>  1 file changed, 158 insertions(+)
> >>>  create mode 100644
> >>> Documentation/devicetree/bindings/sound/tesla,fsd-card.yaml
> >>>
> >>> diff --git
> >>> a/Documentation/devicetree/bindings/sound/tesla,fsd-card.yaml
> >>> b/Documentation/devicetree/bindings/sound/tesla,fsd-card.yaml
> >>> new file mode 100644
> >>> index 000000000000..4bd590f4ee27
> >>> --- /dev/null
> >>> +++ b/Documentation/devicetree/bindings/sound/tesla,fsd-card.yaml
> >>> @@ -0,0 +1,158 @@
> >>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) #
> >>> +Copyright
> >>> +2022 Samsung Electronics Co. Ltd.
> >>> +%YAML 1.2
> >>> +---
> >>> +$id:
> >>> +https://protect2.fireeye.com/v1/url?k=4ae54403-157e7d1c-4ae4cf4c-
> >> 000b
> >>> +abdfecba-9eb398ea304f8ae8&q=1&e=4935bed0-ce62-47dd-8faf-
> >> 4750b01e22d3&
> >>>
> >>
> +u=http%3A%2F%2Fdevicetree.org%2Fschemas%2Fsound%2Ftesla%2Cfsd-
> >> card.ya
> >>> +ml%23
> >>> +$schema:
> >>> +https://protect2.fireeye.com/v1/url?k=8c72226e-d3e91b71-8c73a921-
> >> 000b
> >>> +abdfecba-3ce999f6c052255b&q=1&e=4935bed0-ce62-47dd-8faf-
> >> 4750b01e22d3&
> >>> +u=http%3A%2F%2Fdevicetree.org%2Fmeta-schemas%2Fcore.yaml%23
> >>> +
> >>> +title: Tesla FSD ASoC sound card driver
> >>> +
> >>> +maintainers:
> >>> +  - Padmanabhan Rajanbabu <p.rajanbabu@samsung.com>
> >>> +
> >>> +description: |
> >>> +  This binding describes the node properties and essential DT
> >>> +entries of FSD
> >>> +  SoC sound card node
> >>> +
> >>> +select: false
> >>
> >> Never apply this schema. Why?
> > Sorry about it, let me change the select property to true in the next
> > patchset
> 
> No, just drop it. Look at other bindings or at example-schema
> 
> >>
> >>> +
> >>> +properties:
> >>> +  compatible:
> >>> +    enum:
> >>> +      - tesla,fsd-sndcard
> >>> +
> >>> +  model:
> >>> +    description: Describes the Name of the sound card
> >>> +    $ref: /schemas/types.yaml#/definitions/string
> >>> +
> >>> +  widgets:
> >>> +    description: A list of DAPM widgets in the sound card. Each
> >>> + entry
> > is a pair
> >>> +      of strings, the first being the widget name and the second
> >>> + being
> > the
> >>> +      widget alias
> >>> +    $ref: /schemas/types.yaml#/definitions/string-array
> >>> +
> >>> +  audio-routing:
> >>> +    description: A list of the connections between audio components.
> > Each entry
> >>> +      is a pair of strings, the first being the connection's sink,
> >>> + the
> > second
> >>> +      being the connection's source
> >>> +    $ref: /schemas/types.yaml#/definitions/string-array
> >>> +
> >>> +  dai-tdm-slot-num:
> >>> +    description: Enables TDM mode and specifies the number of TDM
> >>> + slots
> > to be
> >>> +      enabled
> >>> +    $ref: /schemas/types.yaml#/definitions/uint32
> >>> +    enum: [0, 1, 2, 3, 4, 5, 6, 7, 8]
> >>
> >> maximum: 8
> > Okay
> >>
> >>> +    default: 2
> >>> +
> >>> +  dai-tdm-slot-width:
> >>> +    description: Specifies the slot width of each TDm slot enabled
> >>> +    $ref: /schemas/types.yaml#/definitions/uint32
> >>> +    enum: [8, 16, 24]
> >>> +    default: 16
> >>
> >> All the above have types defined. You should not be redefining the types.
> > Okay
> >>
> >>> +
> >>> +  dai-link:
> >>> +    description: Holds the DAI link data between CPU, Codec and
> > Platform
> >>> +    type: object
> >>
> >>        additionalProperties: false
> > okay
> >>
> >>> +    properties:
> >>> +      link-name:
> >>> +        description: Specifies the name of the DAI link
> >>> +        $ref: /schemas/types.yaml#/definitions/string
> >>> +
> >>> +      dai-format:
> >>> +        description: Specifies the serial data format of CPU DAI
> >>> +        $ref: /schemas/types.yaml#/definitions/string
> >>> +
> >>> +      tesla,bitclock-master:
> >>> +        description: Specifies the phandle of bitclock master DAI
> >>> +        $ref: /schemas/types.yaml#/definitions/phandle
> >>> +
> >>> +      tesla,frame-master:
> >>> +        description: Specifies the phandle of frameclock master DAI
> >>> +        $ref: /schemas/types.yaml#/definitions/phandle
> >>
> >> These are common properties. Drop 'tesla'.
> > Okay
> >>
> >>> +
> >>> +      cpu:
> >>> +        description: Holds the CPU DAI node and instance
> >>> +        type: object
> >>
> >>            additionalProperties: false
> > Okay
> >>
> >>> +        properties:
> >>> +          sound-dai:
> >>> +            description: Specifies the phandle of CPU DAI node
> >>> +            $ref: /schemas/types.yaml#/definitions/phandle-array
> >>> +
> >>> +        required:
> >>> +          - sound-dai
> >>> +
> >>> +      codec:
> >>> +        description: Holds the Codec DAI node and instance
> >>> +        type: object
> >>
> >>            additionalProperties: false
> > Okay
> >>
> >>> +        properties:
> >>> +          sound-dai:
> >>> +            description: Specifies the phandle of Codec DAI node
> >>> +            $ref: /schemas/types.yaml#/definitions/phandle-array
> >>
> >> Already has a type. Need to define how many entries (maxItems: 1 ?).
> > Okay. I'll update in the upcoming patch set
> >>
> >>> +
> >>> +        required:
> >>> +          - sound-dai
> >>> +
> >>> +    required:
> >>> +      - link-name
> >>> +      - dai-format
> >>> +      - tesla,bitclock-master
> >>> +      - tesla,frame-master
> >>> +      - cpu
> >>> +
> >>> +dependencies:
> >>> +  dai-tdm-slot-width: [ 'dai-tdm-slot-num' ]
> >>
> >> This should be captured with tdm-slot.txt converted to schema.
> > Okay
> >>
> >>> +
> >>> +required:
> >>> +  - compatible
> >>> +  - model
> >>> +  - dai-link
> >>> +
> >>> +additionalProperties: false
> >>> +
> >>> +examples:
> >>> +  - |
> >>> +    sound {
> >>> +        compatible = "tesla,fsd-sndcard";
> >>> +        status = "disabled";
> >>
> >> Why have a disabled example? Other than your example won't pass your
> >> schema.
> > Thanks for noticing, I'll double check and change the example keeping
> > the status as enabled
> 
> No, just drop. Start with example-schema instead.
> 
> Best regards,
> Krzysztof