[alsa-devel] ASoC Sound Driver I2S over LPE, Intel Baytrail SoC. MinnowBoard Max

[Michael Pogrebinsky]

Hi Pierre,
Thank you so much for your reply, and for sharing your repo.
This is great news for me, as I was blocked for a while on this issue. And
I'm particularly happy that this is all done on top of the 4.3 Kernel, this
is very professional of you. I will try the code, and definitely let you
know how it goes, or if I have any issues.

Thank you again,
Michael



On Tue, Nov 10, 2015 at 10:53 AM, Pierre-Louis Bossart <
pierre-louis.bossart at linux.intel.com> wrote:

> Hi Michael,
>
> I have the MinnowBoard Max with Baytrail Atom (ValleyView) SoC.
>> I'm attempting to write an Alsa (ASoC) driver for my sound card to
>> work with this board.
>> PCM should work through I2S for this sound card I have.
>>
>
> Good to hear. There are several folks in Intel trying to enable I2S over
> the low-speed connector for 3rd party enablement or help 'makers'. This is
> still work-in-progress but we can already share some elements of
> information based on our own experience:
> 1. the default 0.82 firmware doesn't enable the I2S pins, we are currently
> using a DSDT override to configure them.
> 2. the audio codec needs to be registered as a child of I2C6 (it's
> typically I2C2 on regular baytrail platforms). this is also part of the
> DSDT override.
> 3. since we need to support multiple audio codecs, we'd like to add a
> mechanism to add information in the SSDT table to be able to boot the same
> kernel and select the right drivers. Alternatively you will have to use the
> DSDT override method until this mechanism is ready.
> 4. there is no MCLK on existing MinnowBoards, so your codec will have to
> drive its PLL from the BLCK. newer versions of the MinnowBoard Turbot will
> support an MCLK but they are in pre-production stage and to the best of my
> knowledge not available commercially yet.
> 5. to get the best long-term support you really want to use the newer
> DPCM-based driver/firmware for e.g 24-bit, TDM and deep-buffer support. We
> have a set of patches that have not been published upstream yet but if you
> are interested you can look at my github
> https://github.com/plbossart/sound/tree/minnow-v4.3-24bit. In theory if
> you take this code and change the DSDT to support your _HID just like it
> was done for the rt5651 the drivers should load and register a sound card.
> Disclaimer: there is no official support on this branch and rebases/fixes
> may happen at any time. the code will be submitted upstream when ready.
>
> If you provide more information on which codec you are trying to link to
> we can help further.
> -Pierre
>



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Michael Pogrebinsky

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