[PATCH v2] powerpc/dts: Add and fix 1588 timer node for eTSEC

[Lu Y.B.]

Hi Scott,

I submitted a v3 patch for this.
Sorry for my misunderstanding and thank a lot.



Best regards,
Yangbo Lu

> -----Original Message-----
> From: Wood Scott-B07421
> Sent: Friday, July 24, 2015 11:08 PM
> To: Lu Yangbo-B47093
> Cc: linuxppc-dev at lists.ozlabs.org; linux-kernel at vger.kernel.org
> Subject: Re: [PATCH v2] powerpc/dts: Add and fix 1588 timer node for
> eTSEC
> 
> On Mon, 2015-07-20 at 01:33 -0500, Lu Yangbo-B47093 wrote:
> > > On Wed, 2015-07-15 at 21:37 -0500, Lu Yangbo-B47093 wrote:
> > > > Any comments?
> > > > Thanks.
> > >
> > > Sorry, I must have missed this on my last time through the patch
> queue.
> > > I see you've decimalized the fiper and max-adj properties, which is
> > > good... but does it really make sense for tmr-add?  I'm not familiar
> > > with what this value represents, but the numbers look more natural as
> hex (e.g.
> > > 0xaaaaaaab versus 2863311531).
> >
> > Yes, the fiper value would be writed into fiper registers. And max-adj
> > value would be used in ptp driver in driver/ptp/.
> > But you insisted that values should be in decimalism in the v1
> > patch... :)
> >
> > See the history :)
> 
> I didn't insist on decimals for *everything*, just where it makes sense,
> and that "it goes in a register" doesn't *automatically* mean that it
> doesn't make sense.
> 
> ################# history ##################
> > > > +  ptp_clock at b0e00{
> > > > +         compatible = "fsl,etsec-ptp";
> > > > +         reg = <0xb0e00 0xb0>;
> > > > +         interrupts = <68 2 0 0 69 2 0 0>;
> > > > +         fsl,tclk-period = <5>;
> > > > +         fsl,tmr-prsc    = <2>;
> > > > +         fsl,tmr-add     = <0xcccccccd>;
> > > > +         fsl,tmr-fiper1  = <0x3b9ac9fb>;
> > > > +         fsl,tmr-fiper2  = <0x00018696>;
> > > > +         fsl,max-adj     = <249999999>;
> > >
> > > Please don't use hex for numbers that make more sense as decimal.
> > > [Lu Yangbo-B47093] The hex value is register value, I think it's
> > > better to use hex.
> >
> > Whether it goes into a register doesn't matter.  Hex values are useful
> > for values which are subdivided into various bitfields, or whose hex
> > representation is simpler than decimal.  I'm not familiar with the
> > details of this hardware, but I doubt the former is the case for
> > 0x3b9ac9fb ==
> > 9999999995 or 0x18696 == 99990.
> >
> > -Scott
> > ######################################
> >
> >
> > >
> > > > > diff --git a/arch/powerpc/boot/dts/p2020rdb-pc.dtsi
> > > > > b/arch/powerpc/boot/dts/p2020rdb-pc.dtsi
> > > > > index c21d1c7..363172d 100644
> > > > > --- a/arch/powerpc/boot/dts/p2020rdb-pc.dtsi
> > > > > +++ b/arch/powerpc/boot/dts/p2020rdb-pc.dtsi
> > > > > @@ -215,12 +215,12 @@
> > > > >     };
> > > > >
> > > > >      ptp_clock at 24e00{
> > > > > -           fsl,tclk-period = <5>;
> > > > > -           fsl,tmr-prsc = <200>;
> > > > > -           fsl,tmr-add = <0xCCCCCCCD>;
> > > > > -           fsl,tmr-fiper1 = <0x3B9AC9FB>;
> > > > > -           fsl,tmr-fiper2 = <0x0001869B>;
> > > > > -           fsl,max-adj = <249999999>;
> > > > > +           fsl,tclk-period = <5>;
> > > > > +           fsl,tmr-prsc    = <2>;
> > > > > +           fsl,tmr-add     = <2863311531>;
> > > > > +           fsl,tmr-fiper1  = <999999995>;
> > > > > +           fsl,tmr-fiper2  = <99990>;
> > > > > +           fsl,max-adj     = <299999999>;
> > > > >     };
> > >
> > > And here, you're changing the value of fsl,tmr-add and fsl,max-adj.
> Why?
> >
> > The old values maybe not calculated base on the default eTSEC system
> > clock value.
> > 1588 timer couldn’t be adjusted correctly by old values.
> 
> Explain in the changelog what was wrong with the old values (don't just
> say "Fix 1588 timer node in file").
> 
> -Scott