[PATCH][v2] powerpc/fsl-booke: Add T1040D4RDB/T1042D4RDB board support

Scott Wood scottwood at freescale.com
Sat Jul 18 03:07:01 AEST 2015


On Fri, 2015-07-17 at 01:17 -0500, Jain Priyanka-B32167 wrote:
> 
> > -----Original Message-----
> > From: Wood Scott-B07421
> > Sent: Friday, July 17, 2015 1:06 AM
> > To: Jain Priyanka-B32167
> > Cc: linuxppc-dev at lists.ozlabs.org
> > Subject: Re: [PATCH][v2] powerpc/fsl-booke: Add T1040D4RDB/T1042D4RDB
> > board support
> > 
> > > > +                i2c at 118100{
> > > > +                      mux at 77{
> > > > +                             compatible = "nxp,pca9546";
> > > > +                             reg = <0x77>;
> > > > +                             #address-cells = <1>;
> > > > +                             #size-cells = <0>;
> > > > +                     };
> > > > +             };
> > > 
> > > A mux with no nodes under it (and yet it has #address-cells/#size-
> > > cells)?
> > > What is it multiplexing?
> > > [Priyanka]: PCA9546 is i2c mux device , to which other i2c devices
> > > (up-to 8
> > > ) can be further connected on output channels On T104xD4RDB,  channel
> > > 0, 1, 3 line are connected to PEX device, Channel 2 to hdmi interface
> > > (initialization is done in u-boot only), other channels are grounded.
> > > So, as such Linux is not using the second level I2C devices connected
> > > on this MUX device. So, I have not shown next level hierarchy.
> > > Should I replace 'mux' with some other name? . Please suggest.
> > 
> > The device tree describes the hardware, not just what Linux uses... but 
> > what
> > I don't understand is why you describe the mux at all if you're not going 
> > to
> > describe what goes underneath it.
> > 
> [Jain Priyanka-B32167] : Is below looks OK?
> i2c at 118100{
>  +                      i2c at 77{
>  +                             compatible = "nxp,pca9546";
>  +                             reg = <0x77>;
>  +                             #address-cells = <1>;
>  +                             #size-cells = <0>;
>  +                     };
>  +             };

Where in my above comment did it appear that I was complaining about the node 
name?

-Scott



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