Date:   Wed, 8 Dec 2021 14:34:48 +0100
From:   Alexandre TORGUE <alexandre.torgue@...s.st.com>
To:     Lee Jones <lee.jones@...aro.org>, Rob Herring <robh+dt@...nel.org>,
        "Ahmad Fatoum" <a.fatoum@...gutronix.de>
CC:     Olivier MOYSAN <olivier.moysan@...s.st.com>,
        Fabrice GASNIER <fabrice.gasnier@...com>,
        <devicetree@...r.kernel.org>, <alsa-devel@...a-project.org>,
        Mark Brown <broonie@...nel.org>,
        <linux-kernel@...r.kernel.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        "Maxime Coquelin" <mcoquelin.stm32@...il.com>,
        <alain.volmat@...s.st.com>, <arnaud.pouliquen@...s.st.com>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [Linux-stm32] [PATCH v2 1/4] ASoC: dt-bindings: stm32: i2s: add
 audio-graph-card port

On 12/8/21 1:08 PM, Lee Jones wrote:
> On Wed, 08 Dec 2021, Alexandre TORGUE wrote:
> 
>> Hi Ahmad
>>
>> On 12/7/21 2:59 PM, Ahmad Fatoum wrote:
>>> Hello Alex,
>>>
>>> On 07.12.21 14:52, Alexandre TORGUE wrote:
>>>> Hi Rob
>>>>
>>>> On 12/1/21 11:34 PM, Rob Herring wrote:
>>>>> On Fri, Nov 26, 2021 at 11:25:27AM +0100, Olivier MOYSAN wrote:
>>>>>> Hi Rob,
>>>>>>
>>>>>> On 11/25/21 10:26 PM, Rob Herring wrote:
>>>>>>> On Thu, 25 Nov 2021 15:40:50 +0100, Olivier Moysan wrote:
>>>>>>>> The STM2 I2S DAI can be connected via the audio-graph-card.
>>>>>>>> Add port entry into the bindings.
>>>>>>>>
>>>>>>>> Signed-off-by: Olivier Moysan <olivier.moysan@...s.st.com>
>>>>>>>> ---
>>>>>>>>      Documentation/devicetree/bindings/sound/st,stm32-i2s.yaml | 5 +++++
>>>>>>>>      1 file changed, 5 insertions(+)
>>>>>>>>
>>>>>>>
>>>>>>> Running 'make dtbs_check' with the schema in this patch gives the
>>>>>>> following warnings. Consider if they are expected or the schema is
>>>>>>> incorrect. These may not be new warnings.
>>>>>>>
>>>>>>> Note that it is not yet a requirement to have 0 warnings for dtbs_check.
>>>>>>> This will change in the future.
>>>>>>>
>>>>>>> Full log is available here: https://patchwork.ozlabs.org/patch/1559750
>>>>>>>
>>>>>>>
>>>>>>> audio-controller@...0b000: 'port' does not match any of the regexes: '^port@[0-9]', 'pinctrl-[0-9]+'
>>>>>>>       arch/arm/boot/dts/stm32mp157a-dk1.dt.yaml
>>>>>>>       arch/arm/boot/dts/stm32mp157c-dk2.dt.yaml
>>>>>>>
>>>>>>
>>>>>> This warning is not a new one.
>>>>>>
>>>>>> The i2s2 node in stm32mp15xx-dkx.dtsi would require the following binding:
>>>>>> port:
>>>>>>       $ref: audio-graph-port.yaml#
>>>>>>       unevaluatedProperties: false
>>>>>>
>>>>>> However the spi binding requires to introduce a unit address:
>>>>>> patternProperties:
>>>>>>      '^port@[0-9]':
>>>>>>        $ref: audio-graph-port.yaml#
>>>>>>        unevaluatedProperties: false
>>>>>>
>>>>>> The warning can be removed by re-ordering the bindings patches in the serie,
>>>>>> as "additionalProperties: true" makes the check more tolerant on extra
>>>>>> properties.
>>>>>
>>>>> That's never right.
>>>>>
>>>>>> The patch "ASoC: dt-bindings: stm32: i2s: add audio-graph-card port" can
>>>>>> even be merely dropped.
>>>>>> So, I suggest to resend the serie without audio-graph-card patch.
>>>>>
>>>>> Only if you aren't using audio-graph-card.
>>>>>
>>>>>>
>>>>>> Does it sound too permissive to you ?
>>>>>
>>>>> I think perhaps you need to combine the schemas into 1. Or you need to
>>>>> restructure your dtsi files such that you only add spi specific
>>>>> properties when spi mode is enabled and only add i2s specific properties
>>>>> when i2s mode is enabled. Or use the /delete-property/ directive.
>>>>
>>>> Initially the aim of this series was to fix a "make W=1" warnings seen on spi and i2s nodes (duplicate unit-address). Moving both nodes in a common node + using a different compatible depending on SPI or I2S usage sounded good) but it is not enough. In this series the common node is named as following: "spi2s2: spi@...0b000". It is fine for a spi usage but if we want to use this "common node" with I2S compatible and specific bindings, the node name remains spi@... and then specific spi checks are done. For this with this series applied we got this issue reported by spi-controller.yaml:
>>>>
>>>> spi@...0b000: port@0: 'compatible' is a required property
>>>>
>>>> So, if we use two separates nodes we got W=1 warning and if we use a common node we got yaml check issue. One possibility would be to use a common node with a new node name (for example i2spi@...) but I think it is not acceptable.
>>>>
>>>> How to progress ?
>>>
>>> Atmel Flexcom can be configured to be either UART, SPI or i2c. Functions
>>> are child nodes of the flexcom node and the MFD driver matching against it,
>>> just configure the operating mode and then calls of_platform_populate.
>>>
>>> Would something along these lines fit here as well?
>>
>> Yes it could but in my mind it was not a MFD as both feature cannot be used
>> at the same time: it is either SPI or I2S and choice is done "statically" in
>> device tree depending board usage.
>>
>> Lee, what it is your feeling about that ? Will you accept to add a MFD
>> driver for this SPI/I2S peripheral whose prurpose is only to populate child
>> node (either SPI or I2S) ?
> 
>  From your description, this doesn't sound like a good fit for MFD.

Thanks Lee for your quick answer. So rename the node frop spi@... to 
i2spi@... (or something else) looks like to be the only solution. 
Depending the compatible used the well schema will be used (if well 
referenced in each stm32 spi and i2s yaml files):

--> spi-controller.yaml in case of "st,stm32h7-spi"

-->audio-controller in case of "st,stm32h7-i2s"

Rob, do you agree?

regards
alex

> 

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