We are using the audio driver included with the windows CE bsp. We need to be able to programatically switch between mic1, mic2, RXIN inputs and speaker, headphone, and I2S outputs in an application. From my understanding, and audio driver is responsible for hooking the windows waveform audio interface calls to support certain mixer functions. After studying the API I wrote an application to query the mixer, lines, and controls, but the result was that I got back mostly empty information and it seems the driver does not support the mixer in the WAI.

It seems that the audio driver runs as a layer on top of the PMIC driver (power management chip which includes the audio). The PMIC driver documentation includes information about setting and retrieving register values by address, through an IOCTL code. However, I have searched and do not have any header file that includes the values for the IOCTL codes that are given. Also the audio driver itself has no documentation. I was thinking about possibly trying to bypass the audio driver by setting registers directly in the PMIC, but I would imagine this is probably undesirable because of possible conflicts with some kind of internal state in the audio driver itself (not to mention the time investment it would take to do this).

I have the following three questions that I need answered.

• Does the audio driver allow me to switch between sources and destinations through an application at run time? (between RXIN, MIC1, MIC2 and speaker, headset, I2S interface) And, if so, how?
• Is there a document for the “Audio driver reference”, online there is a document on everything but the audio driver. Are there IOCTL codes for the audio driver?
• What are the values for the IOCTL codes and the format for the structs for the PMIC driver? I do not seem to have the required header file which should include the IOCTL codes and STRUCTS.