[alsa-devel] [PATCH v3] ASoC: simple-card: add Device Tree support

[Kuninori Morimoto]

Hi Mark (Brown), Mark (Rutland)

I had sent v4 patch, but I removed simple-card,card-name on it.
But, as Mark (Brown) explained, I think simple-card,card-name
is very helpful for users.
I can send v5 patch (with it), or incremental patch if we can have it.
So, I need your comment

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> On Thu, Oct 24, 2013 at 06:17:59PM +0100, Mark Rutland wrote:
> > On Fri, Oct 04, 2013 at 01:04:41AM +0100, Kuninori Morimoto wrote:
> 
> > > +- simple-audio,card-name		: simple-audio card name
> 
> > What's this used for?
> 
> This serves two useful functions.  One is that this is used for display
> to users so they have a friendly name for the sound card (it is
> relatively common to have multiple sound cards in the system).  The
> other is that it is essentially a compatibility string for configuration
> - you get a lot of sound devices that are electrically identical and
> hence look the same from a driver point of view but due different
> physical form factors should be configured differently.
> 
> > > +- format				: specific format if needed, see below
> > > +- frame-master				: frame master
> > > +- bitclock-master			: bitclock master
> > > +- bitclock-inversion			: clock inversion
> > > +- frame-inversion			: frame inversion
> 
> > What do these mean? Repeating the name without a dash is completely unhelpful.
> > Describe what these imply.
> 
> These are all boolean propeties.  The meanings should be obvious or at
> least very easily discoverable to anyone with any familiarity with audio
> hardware; if you can understand what to do with them they should be OK.
> 
> > > +- clocks				: phandle for system clock rate
> 
> > Just one clock?
> 
> This is a limitation from the simple card, anything that needs more
> complex clocking should be using a different binding.
> 
> > > +- system-clock-frequency		: system clock rate
> > > +					  it will overwrite clocks's rate
> 
> > This seems very odd.
> 
> > Why do you want to overwrite a clock's rate?
> 
> It's relatively common to derive the audio clock from a general purpose
> programmable clock which needs to be configured appropriately for use.
> 
> > > +simple-audio,format
> > > +	"i2s"
> > > +	"right_j"
> > > +	"left_j"
> > > +	"dsp_a"
> > > +	"dsp_b"
> > > +	"ac97"
> > > +	"pdm"
> > > +	"msb"
> > > +	"lsb"
> 
> > What do these mean? Why are they not described when the property was defined above?
> 
> This is another one where the names should be clear for people familiar
> with the hardware, they're well known terms.
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Best regards
---
Kuninori Morimoto