Re: [alsa-devel] [PATCH 01/14] Documentation: Add SoundWire summary

From: Vinod Koul
Date: Mon Oct 23 2017 - 07:13:59 EST


On Mon, Oct 23, 2017 at 08:50:50AM +0100, Mark Brown wrote:
> On Sat, Oct 21, 2017 at 04:58:40PM +0530, Vinod Koul wrote:
> > On Sat, Oct 21, 2017 at 09:57:44AM +0100, Mark Brown wrote:
>
> > > There's lots of perfectly normal nouns in this document like Slave here
> > > which are randomly capitalized. Is there some great reason for this?
> > > It makes the document pretty distracting to read.
>
> > Slave, SoundWire etc are MIPI definitions hence capitalized.
>
> Slave? Really?
>
> > > > +provides capabilities information. DT support is not implemented at this
> > > > +time but should be trivial to add since capabilities are enabled with the
> > > > +device_property_ API.
>
> > > Since we're making this up from whole cloth rather than following an
> > > existing standard let's get a DT binding document together and review
> > > the properties that are getting defined.
>
> > I don't have a DT to test, but looking at Slimbus code I guess assumptions
> > are fair and we seem to have similar concepts and implementation.
>
> That's fine, we can still review binding documents.

I am not really sure about that part, let me see if I can come up or worst
case not talk about DT at all.

> > > > +The MIPI specification requires each Slave interface to expose a unique
> > > > +48-bit identifier, stored in 6 read only dev_id registers. This dev_id
> > > > +identifier contains vendor and part information, as well as a field enabling
> > > > +to differentiate between identical components. An additional class field is
> > > > +currently unused. Slave driver is written for the specific 48-bit
> > > > +identifier, Bus enumerates the Slave device based on the 48-bit identifier.
>
> > > So this says that the instance identifer is part of the device
> > > identifier but the driver should bind to the whole device identifer?
> > > I'd expect the driver to bind to everything except the instance
> > > identifer.
>
> > Other parts are still TBD and not really used, like Device Class, Spec
> > version. We are using only mfg id and part id for binding.
>
> That's not what the document claims.

Sorry about that fixed now. Thanks for pointing

--
~Vinod