[alsa-devel] [PATCH 2/3] drm/i2c: tda998x: Register ASoC hdmi-codec and add audio DT binding

[Russell King - ARM Linux]

On Fri, Aug 05, 2016 at 05:59:59PM +0100, Mark Brown wrote:
> On Fri, Aug 05, 2016 at 05:48:45PM +0100, Russell King - ARM Linux wrote:
> > On Fri, Aug 05, 2016 at 12:02:39PM +0300, Jyri Sarha wrote:
> 
> > > That may be a problem. The ASoC card device tree binding current looks
> > > for the ASoC DAI's parent's of-node if it can not find the node for the
> > > DAI-device itself.
> 
> > I don't follow.  The "parent" of this audio_pdev device above is
> > the "platform" device - /sys/devices/platform.  If ASoC is
> > referencing the parent of the above platform device for some
> > reason, it's probably not going to get anything useful from such
> > an attempt.
> 
> > Any other ASoC codec driver where the codec platform device was
> > declared with a NULL parent pointer also ends up as a child of
> > that same location.
> 
> > I'd _really_ be surprised if ASoC is even doing what you describe,
> > because such an action is totally illogical (as can be seen from
> > my description above.)
> 
> We do have some stuff in there in order to handle MFDs - they'll
> instantiate a Linux-internal virtual platform device as a child of the
> DT device that represents the device as a whole.  We're definitely not
> expecting to find anything for parentless platform devices though, it's
> only done if the ASoC level device has no of_node and the parent does.

And if we make the hdmi-codec device a child of the I2C device which
does have an of-node, what will happen?

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