[alsa-devel] Question about struct snd_soc_dai() :: cpu_dai->codec

[Vinod Koul]

On Fri, Jul 29, 2016 at 11:07:49AM +0200, Lars-Peter Clausen wrote:
> On 07/29/2016 02:30 AM, Takashi Sakamoto wrote:
> > Lars,
> > 
> > On Jul 29 2016 05:33, Lars-Peter Clausen wrote:
> >> Hotplug is something that always pops up sooner or later. E.g. if someone
> >> puts a ASoC supported CODEC on a hot-pluggable device (maybe USB) we
> >> don't want to duplicate the code, but be able to reuse.
> > 
> > (A bit to sidetrack)
> > 
> > To me, it's unclear for devices on USB. When ALSA SoC part supports these
> > devices, what is the scenario you assumed? In short, assuming we put codes
> > to ALSA SoC part, what is the shape of the corresponding devices and links
> > of pairs of endpoints? Additionally, in this case, what codes are able to be
> > reused?
> 
> Lets say you have USB stick with a small micro controller or FPGA which has
> a USB interface on one side and a I2S and I2C interface on the other side.
> The I2S and I2C are connected to a CODEC. I2S for data, I2C for control. If
> the interface is implemented in a way so that it is just a simple USB to I2C
> bridge, this means the raw I2C commands are send over the USB interface you
> can implement a I2C adapter driver for this bridge. If you have that you can
> instantiate the existing ASoC CODEC driver, which is a I2C device driver, on
> the bus registered by the adapter.

That still seems a bit fancy hardware :)

If we can reasonably support this, I am for it. But not making stuff
overtly complex...

-- 
~Vinod