Am Montag, den 19.08.2013, 11:01 +0100 schrieb Mark Rutland: > On Mon, Aug 19, 2013 at 10:50:43AM +0100, Nicolin Chen wrote: > > Hi, > > > > On Mon, Aug 19, 2013 at 10:24:58AM +0100, Mark Rutland wrote: > > > Is this used semantically, or is it a completely arbitrary string? In > > > either case I don't see why the compatible string doesn't give the > > > driver enough to have a sensible value. > > > > > > I'm confused as to why we need this. The phrase "user-visible" in a > > > device description seems very odd. > > > > The string would be in the ALSA device list: > > ALSA device list: > > #0: imx-spdif > > > > I think it can be a sort of arbitrary as long as users know which this > > device exactly is when they catch the name by 'aplay -l' or 'arecord -l' > > > > The phrase "user-visible" is being used in many current docs, I don't > > dare to change it unless a sage gives me a suggestion. > > I can see that there is entrenched usage, but this really seems to be > embedding Linux-specific implementation details into the dt. I don't see > why the driver cannot select a sensible name, but perhaps I'm missing > something. > > Mark, is there any reason we need to handle the user-visible name of the > device this way? > > > > > > > + > > > > + - spdif-controller : The phandle of the i.MX S/PDIF controller > > > > + > > > > + > > > > +Optional properties: > > > > + > > > > + - spdif-transmitter : The phandle of the spdif-transmitter dummy > > > > codec > > > > + > > > > + - spdif-receiver : The phandle of the spdif-receiver dummy codec > > > > + > > > > +* Note: At least one of these two properties should be set in the DT > > > > binding. > > > > > > Are all four units (comlpex,controller,transmitter,receiver) really > > > separate blocks? > > > > At least they are separate drivers as I mentioned in the commit comments. > > I'm not sure that the boundary of Linux drivers should necessarily > determine the way we carve up the description of IP blocks, though > presumably it's a pretty sensible way of carving it up or we wouldn't > have done it.
The transmitter and receiver can be real external codec devices with S/PDIF input or output pads connected to the i.MX S/PDIF. One example would be the Analog Devices ADV7612 HDMI receiver, which can output audio taken from HDMI input via S/PDIF (just as via I2S). The dummy codec devices are just needed if the S/PDIF pads are directly routed to externally accessible connectors. regards Philipp _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
