Hello. I had such situation. I developed a device board. Its function is a hydrolocation. It is developed on the basis of OMAP-L138 SOM-M1 firms Logic. To signal digitization it is applied PCM4204 Texas Instruments firms. It is necessary for me to carry out communications between OMAP-l138 and PCM4204. At first I implemented the message between kernel DSP and PCM4204. Driver MCASP working in the environment of DSP/BIOS 5.41 was for this purpose used. However then for technical reasons there was a necessity that the message was carried out between kernel ARM and PCM4204. That is the driver in the environment of Linux is necessary. For an application creation in the environment of Linux I use ti-dvsdk_omapl138-evm_4_02_00_06.Very well the architecture of ALSA is described in this article http://processors.wiki.ti.com/index.php/AM335x_Audio_Driver%27s_Guide. Unfortunately, codec driver for PCM4204 doesn't exist.I need your council. In what direction to me to move further? To try to alter the MCasP driver. To make it independent from ALSA. Or to try to write the codec driver for PCM4204. What will demand less efforts and time?
Thanks for attention.