[PATCH] ASoC: max98357a: set channels_max to 4

Tue Jun 15 09:00:10 PDT 2021

On 6/15/21 10:47 AM, Cheng-yi Chiang wrote:
> Hi Tzung-Bi,
> 
> On a platform, the four max98357a amps will be controlled by only one
> codec device, as GPIO for SD_MODE is shared by all amps and is the
> only thing to be controlled.
> In this sense, I think we can treat max98357a DAI as if it supports
> four channels.
> I understand that this solution is not scalable, because one can
> control as many amps as they want.
> Theoretically, the number of supported channels by this codec device
> is unlimited.
> I found that rt1015.c has similar usage.
> Do you have a better suggestion to support this kind of use case ?
> Thanks!

please don't top-post...

I don't think it's correct to declare 4-channel support at the 
individual codec DAI level when in practice each device will be provided 
with a TDM mask that selects two slots.

This is confusing device capabilities and TDM link configuration.

> On Tue, Jun 1, 2021 at 2:20 PM Tzung-Bi Shih <tzungbi at google.com> wrote:
>>
>> On Wed, May 26, 2021 at 11:47 PM Judy Hsiao <judyhsiao at chromium.org> wrote:
>>> Sets channels_max to 4 to support QUAD channel.
>>
>> Could you point out probably the up-to-date MAX98357A datasheet for
>> 4-channel support?
>>
>> On a related note, from the public datasheet I could find[1], "Table
>> 5" only shows 2 channel's configuration.
>>
>> [1]: https://pdf1.alldatasheet.com/datasheet-pdf/view/623796/MAXIM/MAX98357A.html