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 <dvh...@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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