Device Interface - Texas Instruments OMAP35 Series User Manual

5.5. Software Interfaces
This section provides the details of the Application Interface and the Driver
Interface for the ALSA Audio driver.
5.5.1. Application Interface
Application developer uses ALSA-lib, a user space library, rather than the kernel
API. The library offers 100% of the functionality of the kernel API, but adds
major improvements in usability, making the application code simpler and better
looking.
The online-documentation for the same is available at:
http://www.alsa-project.org/alsa-doc/alsa-lib/

5.5.1.1. Device Interface

The operational interface in /dev/ contains three main types of devices: (a)
PCM devices for recording or playing digitized sound samples, (b) CTL devices
that allow manipulating the internal mixer and routing of the card, and (c) MIDI
devices to control the MIDI port of the card, if any.
Table 5.3. Device Interface
5.5.1.2. Proc Interface
The /proc/asound kernel interface is a status and configuration interface. A
lot of useful information about the sound system can be found in the /proc/
asound subdirectory.
See the table below for different proc entries in /proc/asound:
56
Name
/dev/snd/controlC0
/dev/snd/pcmC0D0c
/dev/snd/pcmC0D0p
Platform Support Products
Description
Control devices (i.e. mixer, etc).
PCM Card 0 Device 0 Capture device.
PCM Card 0 Device 0 Playback device..
Audio Driver
Software Interfaces
Version 02.01.01.08