linux-kernel - Re: [EXTERNAL] Re: [PATCH v2 2/5] ASoC: dt-bindings: Add tas2781 amplifier

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Message-ID: <1959eb8a-d55f-5f62-2b41-0e7ea41b27b2@linaro.org>
Date:   Thu, 11 May 2023 11:01:12 +0200
From:   Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To:     "Ding, Shenghao" <shenghao-ding@...com>
Cc:     "Lu, Kevin" <kevin-lu@...com>,
        "alsa-devel@...a-project.org" <alsa-devel@...a-project.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "Xu, Baojun" <x1077012@...com>, "Gupta, Peeyush" <peeyush@...com>,
        "Navada Kanyana, Mukund" <navada@...com>,
        "gentuser@...il.com" <gentuser@...il.com>,
        "Ryan_Chu@...tron.com" <Ryan_Chu@...tron.com>,
        "Sam_Wu@...tron.com" <Sam_Wu@...tron.com>,
        Shenghao Ding <13916275206@....com>,
        "broonie@...nel.org" <broonie@...nel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "krzysztof.kozlowski+dt@...aro.org" 
        <krzysztof.kozlowski+dt@...aro.org>,
        "robh+dt@...nel.org" <robh+dt@...nel.org>,
        "lgirdwood@...il.com" <lgirdwood@...il.com>,
        "perex@...ex.cz" <perex@...ex.cz>,
        "pierre-louis.bossart@...ux.intel.com" 
        <pierre-louis.bossart@...ux.intel.com>
Subject: Re: [EXTERNAL] Re: [PATCH v2 2/5] ASoC: dt-bindings: Add tas2781
 amplifier

On 10/05/2023 16:03, Ding, Shenghao wrote:
> 
>> +    items:
>> +      minimum: 0x38
>> +      maximum: 0x3f
> 
> ... So these are fixed? No need to encode them in such case...
> 
> and anyway actually I agree with Rob here - these addresses should be put in reg.
> [DING] if all the put in reg, the i2c_probe will be called several time. The code don not want to register several codecs, but one codec including several tas2781s.

Eh? Why and what would call probe multiple times for one device? It's
the first time I hear... I don't know, maybe Linux I2C has some
specifics, but sounds surprising.

> 
>> +      description:
>> +        I2C address of the device for different audio slots,
>> +        useless in mono case.
>> +
>> +  ti,broadcast-addr:
>> +    $ref: /schemas/types.yaml#/definitions/uint32
>> +    description:
>> +      Generic I2C address for all the tas2781 devices in
>> +      purpose of I2C broadcast during the multi-device
>> +      writes, useless in mono case.
> 
> Probably you can figure it out from previous addresses and there is no need for this property.
> [Ding] this address is the common address for all the tas2781, it can be used for dsp firmware downloading to all the tas2781s in parallel, which can save more downloading time

So the answer is yes? Then please drop it... If not, say why it cannot
be deducted from other addresses (e.g. last address + 1).

Best regards,
Krzysztof