Re: [PATCH v3 4/6] mfd: dt: Add bindings for the Aspeed LPC Host Controller (LHC)

[Andrew Jeffery <andrew@aj.id.au>]

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On Mon, 2016-12-12 at 09:30 -0600, Rob Herring wrote:
> On Tue, Dec 06, 2016 at 01:53:19PM +1100, Andrew Jeffery wrote:
> > The LPC bus pinmux configuration on fifth generation Aspeed SoCs depends
> > on bits in both the System Control Unit and the LPC Host Controller.
> > 
> > The Aspeed LPC Host Controller is described as a child node of the
> > LPC host-range syscon device for arbitration of access by the host
> > controller and pinmux drivers.
> > 
> > > > Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
> > ---
> >  .../devicetree/bindings/mfd/aspeed-lpc.txt         | 22 ++++++++++++++++++++++
> >  1 file changed, 22 insertions(+)
> > 
> > diff --git a/Documentation/devicetree/bindings/mfd/aspeed-lpc.txt b/Documentation/devicetree/bindings/mfd/aspeed-lpc.txt
> > index a97131aba446..9de318ef72da 100644
> > --- a/Documentation/devicetree/bindings/mfd/aspeed-lpc.txt
> > +++ b/Documentation/devicetree/bindings/mfd/aspeed-lpc.txt
> > > > @@ -109,3 +109,25 @@ lpc: lpc@1e789000 {
> > > >  	};
> >  };
> >  
> > +Host Node Children
> > +==================
> > +
> > +LPC Host Controller
> > +-------------------
> > +
> > +The Aspeed LPC Host Controller configures the Low Pin Count (LPC) bus behaviour
> > +between the host and the baseboard management controller. The registers exist
> > +in the "host" portion of the Aspeed LPC controller, which must be the parent of
> > +the LPC host controller node.
> > +
> > +Required properties:
> > > > +- compatible:		"aspeed,ast2500-lhc";
> > > > +- reg:			contains offset/length value of the LHC memory
> > +			region.
> 
> How many regions? Looks like 2.

Yes, two. The first region is registers configuring various LPC host
controller properties. The second region is for configuring the LPC
serial IRQ trigger modes.

Would you like me to say as much in the patch? It's not a completely
clear split of functionality as other serial IRQ properties are also
described in the first region. Maybe describing the datasheet's
register names for the regions (LHCR[0-8] for the first, LHCR[A-B] for
the second) would help?

Cheers,

Andrew

> 
> > +
> > +Example:
> > +
> > > > +lhc: lhc@20 {
> > > > +	compatible = "aspeed,ast2500-lhc";
> > > > +	reg = <0x20 0x24 0x48 0x8>;
> > +};
> > -- 
> > 2.9.3
> > 

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