On Wed, Jan 25, 2023 at 8:30 PM Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx> wrote: > > > > On 1/25/23 05:21, Muni Sekhar wrote: > > Hi, > > > > struct snd_pcm_ops callbacks can be used for sending\receiving PDM > > audio data to and from a sound card? Or is it only designed for PCM > > audio data? > > It depends what side of the sound card you are looking at, the physical > interface with external devices or the userspace interface. I am looking at the userspace interface side. > > PDM can be supported at the physical interface level as long as there is > a conversion to PCM somewhere in the hardware. Userspace will > play/record PCM. See examples in many codecs and SOCs. > > There is also the possibility of packing PDM (aka DSD) as pseudo-PCM, > that's a trick used by several USB cards. In that case of course the > sound card cannot apply any processing to the data and is just a > pass-through module. > > -- Thanks, Sekhar
