linux-kernel - Re: [PATCH 2/2] Documentation: cs35l41: Shared boost properties

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Date:   Tue, 7 Feb 2023 17:48:59 +0100
From:   Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To:     Lucas Tanure <lucas.tanure@...labora.com>,
        David Rhodes <david.rhodes@...rus.com>,
        Charles Keepax <ckeepax@...nsource.cirrus.com>,
        Liam Girdwood <lgirdwood@...il.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Mark Brown <broonie@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Jaroslav Kysela <perex@...ex.cz>, Takashi Iwai <tiwai@...e.com>
Cc:     alsa-devel@...a-project.org, devicetree@...r.kernel.org,
        patches@...nsource.cirrus.com, linux-kernel@...r.kernel.org,
        kernel@...labora.com
Subject: Re: [PATCH 2/2] Documentation: cs35l41: Shared boost properties

On 07/02/2023 17:34, Lucas Tanure wrote:
> On 07-02-2023 16:13, Krzysztof Kozlowski wrote:
>> On 07/02/2023 16:46, Lucas Tanure wrote:
>>>>> +      Shared boost allows two amplifiers to share a single boost circuit by
>>>>> +      communicating on the MDSYNC bus. The passive amplifier does not control
>>>>> +      the boost and receives data from the active amplifier. GPIO1 should be
>>>>> +      configured for Sync when shared boost is used. Shared boost is not
>>>>> +      compatible with External boost. Active amplifier requires
>>>>> +      boost-peak-milliamp, boost-ind-nanohenry and boost-cap-microfarad.
>>>>>          0 = Internal Boost
>>>>>          1 = External Boost
>>>>> +      2 = Reserved
>>>>
>>>> How binding can be reserved? For what and why? Drop. 2 is shared active,
>>>> 3 is shared passive.
>>> 2 Is shared boost without VSPK switch, a mode not supported for new
>>> system designs. But there is laptops using it, so we need to keep
>>> supporting in the driver.
>>
>> That's not the answer. 2 is nothing here, so it cannot be reserved.
>> Aren't you mixing now some register value with bindings?
>>
>> Best regards,
>> Krzysztof
>>
>>
> I have added a new patch with propper documentation.
> And I would like to use 3 and 4 for shared boost as 
> CS35L41_EXT_BOOST_NO_VSPK_SWITCH already exist as 2 and is used in the 
> current driver.

I don't see CS35L41_EXT_BOOST_NO_VSPK_SWITCH in the bindings.

> The laptop that uses CS35L41_EXT_BOOST_NO_VSPK_SWITCH doesn't have the 
> property "cirrus,boost-type", but to make everything consistent I would 
> prefer to use 3 and 4 for the new boost types.
> Is that ok with you?

I don't see how it is related. The value does not exist, so whether
laptop has that property or not, is not really related, right?

Best regards,
Krzysztof