[MinnowBoard] Where is the MBM I2S driver in Linux

[li yuqian]

Hi Darren,

Thanks for the reply.

I check those driver, and i can understand there are three parts for the
LPE driver to working, special for the LPE firmware need to adde it. i can
figure it out in the
https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/tree/sound/soc/intel/sst-acpi.c?id=refs/tags/v4.0.4
line 249 and 250.

but when i checked that sst-acpi.c, i found the baytrial sst is not support
the DMA data transfer, see the resindex_dma_base = -1 in line 262 and line
51 /* DMA only valid when resindex_dma_base != -1*/

Am i correct? the MBM i2s does not support DMA data transfer?

Thanks.

2015-06-02 4:11 GMT+08:00 Darren Hart <dvhart at linux.intel.com>:

> On 5/30/15 7:17 PM, li yuqian wrote:
> > i checked the mainline kernel, seems there is a I2S driver with DMA for
> > the MBM, if i want use I2S to connect a codec, where i can find the MBM
> > i2s driver?
>
> Thanks to Kevin Strasser for educating me on the various components.
>
> There isn't an I2S bus driver like there is for SPI, I2C, etc. There are
> three components:
>
> 1) LPE Firmware for the SoC
> This communicates directly with the ADSP and I2S hw. You can find a
> build for Baytrail in the upstream linux-firmware repo, named:
> "fw_sst_0f28.bin-48kHz_i2s_master". This will need to get installed to
> the rootfs as "/lib/firmware/intel/fw_sst_0f28.bin-48kHz_i2s_master".
>
> 2) Machine-codec specific driver
> Assuming you are using the latest upstream kernel sources, you can find
> all the LPE machine drivers in "sound/soc/intel/boards". A corresponding
> machine driver for a Bay Trail SoC using the max98090 codec is
> "sound/soc/intel/boards/byt-max98090.c". The machine driver depends on
> the codec driver and LPE platform driver. LPE platform driver files for
> BYT: "sound/soc/intel/baytrail/*"
>
> 3) Codec driver
> For example: "sound/soc/codecs/max98090.c"
>
>
> --
> Darren Hart
> Intel Open Source Technology Center
>
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