As a reference you can look at the linux driver implementation for imx6 at
the next directories:
<kernel_imx>/linux/drivers/mxc/asrc
<kernel_imx>/linux/include/linux/
<kernel_imx>/linux/sound/soc/imx/
<kernel_imx>/linux/sound/soc/codec/
and the next files:
mxc_asrc.c ASRC driver implementation codes including stream interface
mxc_asrc.h ASRC register definitions and export function declarations
imx-cs42888.c memory to ASRC to ESAI TX implementation in 7.1 audio codec machine driver.
imx-pcm-dma-mx2.c memroy to ASRC to ESAI TX implementation in 7.1 audio codec platform driver
imx-esai.c memroy to ASRC to ESAI TX implementation in 7.1 audio codec cpu driver.
cs42888.c memory to ASRC to ESAI TX implementation in 7.1 audio codec codec driver.