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Date:   Wed, 17 May 2023 17:05:42 +0200
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Subject: Re: [EXTERNAL] Re: [PATCH v2 2/5] ASoC: dt-bindings: Add tas2781
 amplifier
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To:     "Ding, Shenghao" <shenghao-ding@ti.com>,
        Mark Brown <broonie@kernel.org>
Cc:     Shenghao Ding <13916275206@139.com>,
        "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
        "krzysztof.kozlowski+dt@linaro.org" 
        <krzysztof.kozlowski+dt@linaro.org>,
        "robh+dt@kernel.org" <robh+dt@kernel.org>,
        "lgirdwood@gmail.com" <lgirdwood@gmail.com>,
        "perex@perex.cz" <perex@perex.cz>,
        "pierre-louis.bossart@linux.intel.com" 
        <pierre-louis.bossart@linux.intel.com>,
        "Lu, Kevin" <kevin-lu@ti.com>,
        "alsa-devel@alsa-project.org" <alsa-devel@alsa-project.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "Xu, Baojun" <x1077012@ti.com>, "Gupta, Peeyush" <peeyush@ti.com>,
        "Navada Kanyana, Mukund" <navada@ti.com>,
        "gentuser@gmail.com" <gentuser@gmail.com>,
        "Ryan_Chu@wistron.com" <Ryan_Chu@wistron.com>,
        "Sam_Wu@wistron.com" <Sam_Wu@wistron.com>
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From:   Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
In-Reply-To: <26c335994d91492eb9439483ac98f61c@ti.com>
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On 17/05/2023 14:24, Ding, Shenghao wrote:
> 
> 
> On 11/05/2023 15:19, Ding, Shenghao wrote:
>>
>> On 11/05/2023 07:49, Mark Brown wrote:
>>>> Missing minItems, but...
>>>
>>>>> +    items:
>>>>> +      minimum: 0x38
>>>>> +      maximum: 0x3f
>>>
>>>> ... So these are fixed? No need to encode them in such case...
>>>
>>> I'm not sure I understand your concern here, there's up to 4 possible 
>>> values from 0x38-0x3f which has more than 4 possible values.
>>
>> Aren't the addresses going to be incremented by one (up to 8 of devices in total)?
> 
> With your style of replies, it looks like you wrote it...
> 
> All the addresses of tas2781 are in range from 0x38 to 0x 3f, the order of them in the audio-slots item are up to the hardware connections.
> I have studied the reg item to save multiple i2c addresses for multiple pieces of tas2781 and found that "'#address-cells':     maximum: 3"
> that means "reg" store not more than three addresses, this can't support the more than 3 pieces of tas2781, 

No entirely. This determines the size of each address, not the number of
addresses.

> such as 4-slot TDM case or multiple dual-membrane speakers case, in such a case, one speaker will use
>  two pieces of tas2781 to boost, usually at least 6 pieces of tas2781 will be used in a laptop or other device.
> 
>>
>> No, the i2c address order is not always monotonic increase or decrease, sometime it would be disorder, according to the application.
>> Each device would have eight possible i2c address, the final address depends on the hardware connections.
> 
> OK, the question about the broadcast is still there - cannot it be deduced?
> 
> The reason to define this item and add it in dts is that tell tas2781 driver code to enable broadcast and its address. 
> Removing this item means disabling broadcast. Do you want to hardcode the global address in the code?
> And this item only used as a flag to enable or disable?
> 
> Best regards,
> Krzysztof
> 

Hi Krzysztof, nice to talk with you!

I really do not know what is here mine what's yours. I could guess, but
we are all a bit busy, so I would appreciate if reading your email was
easier for me.

Best regards,
Krzysztof