On Wed, Jun 16, 2021 at 12:00 AM Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx> wrote: > > > > 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... Hi Pierre-Louis, I am sorry about that! > > > 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. On this platform there is no TDM support, so there were two I2S data lines. > > This is confusing device capabilities and TDM link configuration. I see that in most of the use cases of multiple amps, we should use codecs and num_codecs of the link. But in this case we only want one codec to control the only GPIO shared by 4 max98357a amps I think we should be able to use 1 max98357 codec and 3 dummy codec to fulfill this use case. Not sure if the number of dummy codec would really matter. With num_codec > 1 we should be able to bypass the channel checking and just use the channel from CPU DAI. Thanks for the suggestion. > > > On Tue, Jun 1, 2021 at 2:20 PM Tzung-Bi Shih <tzungbi@xxxxxxxxxx> wrote: > >> > >> On Wed, May 26, 2021 at 11:47 PM Judy Hsiao <judyhsiao@xxxxxxxxxxxx> 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
