linux-kernel - Re: [PATCH v2 1/4] dt-bindings: bluetooth: add 'qcom,product-variant'

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Message-ID: <d2bfeaed-818d-4440-a88b-106a334caa22@quicinc.com>
Date: Thu, 21 Nov 2024 12:44:55 +0800
From: Cheng Jiang <quic_chejiang@...cinc.com>
To: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
CC: Marcel Holtmann <marcel@...tmann.org>,
        Luiz Augusto von Dentz
	<luiz.dentz@...il.com>,
        Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski
	<krzk+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Bjorn Andersson
	<andersson@...nel.org>,
        Konrad Dybcio <konradybcio@...nel.org>,
        "Balakrishna
 Godavarthi" <quic_bgodavar@...cinc.com>,
        Rocky Liao
	<quic_rjliao@...cinc.com>, <quic_zijuhu@...cinc.com>,
        <linux-bluetooth@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <linux-arm-msm@...r.kernel.org>,
        <quic_mohamull@...cinc.com>
Subject: Re: [PATCH v2 1/4] dt-bindings: bluetooth: add 'qcom,product-variant'

Hi Dmitry,

On 11/21/2024 12:38 PM, Dmitry Baryshkov wrote:
> On Thu, 21 Nov 2024 at 06:02, Cheng Jiang <quic_chejiang@...cinc.com> wrote:
>>
>> Hi Dmitry,
>>
>> On 11/20/2024 6:43 PM, Dmitry Baryshkov wrote:
>>> On Wed, Nov 20, 2024 at 05:54:25PM +0800, Cheng Jiang wrote:
>>>> Several Qualcomm projects will use the same Bluetooth chip, each
>>>> focusing on different features. For instance, consumer projects
>>>> prioritize the A2DP SRC feature, while IoT projects focus on the A2DP
>>>> SINK feature, which may have more optimizations for coexistence when
>>>> acting as a SINK. Due to the patch size, it is not feasible to include
>>>> all features in a single firmware.
>>>>
>>>> Therefore, the 'product-variant' devicetree property is used to provide
>>>> product information for the Bluetooth driver to load the appropriate
>>>> firmware.
>>>>
>>>> If this property is not defined, the default firmware will be loaded,
>>>> ensuring there are no backward compatibility issues with older
>>>> devicetrees.
>>>>
>>>> The product-variant defines like this:
>>>>   0 - 15 (16 bits) are product line specific definitions
>>>>   16 - 23 (8 bits) are for the product line.
>>>>   24 - 31 (8 bits) are reserved for future use, 0 currently
>>>
>>> Please use text strings instead of encoding this information into random
>>> integers and then using just 3 bits out of 32.
>> Ack. Originally intended to make it more flexible for future use. It can be
>> text strings for current requirement.
> 
> No, fixed-format data isn't flexible. Fine-grained properties are.
> Please define exactly what is necessary rather than leaving empty
> holes "for future expansion".=
Got it. Thank you for the guidance. 
> 
>>>
>>>>
>>>> |---------------------------------------------------------------------|
>>>> |                       32 Bits                                       |
>>>> |---------------------------------------------------------------------|
>>>> |  31 - 24 (bits)   |    23 - 16 (bits)   | 15 - 0 (16 bits)          |
>>>> |---------------------------------------------------------------------|
>>>> |   Reserved        |    0: default       | 0: default                |
>>>> |                   |    1: CE            |                           |
>>>> |                   |    2: IoT           |                           |
>>>> |                   |    3: Auto          |                           |
>>>> |                   |    4: Reserved      |                           |
>>>> |---------------------------------------------------------------------|
>>>>
>>>> Signed-off-by: Cheng Jiang <quic_chejiang@...cinc.com>
>>>> ---
>>>>  .../bindings/net/bluetooth/qualcomm-bluetooth.yaml          | 6 ++++++
>>>>  1 file changed, 6 insertions(+)
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/net/bluetooth/qualcomm-bluetooth.yaml b/Documentation/devicetree/bindings/net/bluetooth/qualcomm-bluetooth.yaml
>>>> index 7bb68311c609..9019fe7bcdc6 100644
>>>> --- a/Documentation/devicetree/bindings/net/bluetooth/qualcomm-bluetooth.yaml
>>>> +++ b/Documentation/devicetree/bindings/net/bluetooth/qualcomm-bluetooth.yaml
>>>> @@ -110,6 +110,12 @@ properties:
>>>>      description:
>>>>        boot firmware is incorrectly passing the address in big-endian order
>>>>
>>>> +  qcom,product-variant:
>>>> +    $ref: /schemas/types.yaml#/definitions/uint32
>>>> +    description:
>>>> +      specify the product information for driver to load the appropriate firmware
>>>
>>> DT describes hardware. Is this a hardware property?
>>
>> It has been added to identify the firmware image for the platform. The driver
>> parses it, and then the rampatch is selected from a specify directory. Currently,
>> there is a 'firmware-name' parameter, but it is only used to specify the NVM
>> (config) file. We also need to specify the rampatch (TLV file).
>>
>>
>> Can we re-use the "firmware-name"? add two segments like the following?
>> firmware-name = "rampatch_xx.tlv",  "nvm_xx.bin";
> 
> I think this is the better solution
Ack. Will submit a new change based on this. 
> 
>>
>> Or add a new property to specify the rampatch file?
>> rampatch-name = "rampatch_xx.tlv";
>>
>>>
>>>> +
>>>> +
>>>>  required:
>>>>    - compatible
>>>>
>>>> --
>>>> 2.25.1
>>>>
>>>
>>
> 
>