[PATCH 1/3] clk: mvebu: add gate ctrl for Prestera kirkwood variants

[Jason Cooper]

On Wed, May 08, 2013 at 09:21:40AM +0200, Sebastian Hesselbarth wrote:
> On 05/08/2013 09:04 AM, Valentin Longchamp wrote:
> >On 05/07/2013 06:36 PM, Sebastian Hesselbarth wrote:
> >>I just checked my mails from late 2012 and there Valentin and I agreed,
> >>that not the missing bits in clock gating control registers was the root
> >>cause of km_kirkwood to hang. It was rather the phy gates (that do not/
> >>not yet exist on DT) that caused it to hang, i.e. when accessing SATA
> >>PHY registers.
> >
> >Yeah you are right, I had forgotten about this test. I just had a look at the
> >board-km_kirkwood.c and I tried to figure out a way to make sure the clock gates
> >bits never get read/written, so never get initialized. But as you say, that's
> >not the real cause of the hang but
> >
> >>Valentin, I am not against an extra clock-gating-ctrl for Prestera but
> >>maybe having an kirkwood.dtsi fork without SATA and other peripherals
> >>will also help?
> >
> >Since it's not the real problem having the extra clock-gating-ctrl would me more
> >consistent with the real Prestera HW, but maybe it's better to keep only one
> >that works for both as it's already the case, it's less code to maintain.
> >
> >A better approach would be to work on the kirkwood.dtsi as you mention it. The
> >SATA node in kirkwood.dtsi is by default disabled, is this enough or should it
> >be moved to kirkwood-6281.dtsi for instance ?
> 
> Valentin,
> 
> I guess for the long run, we will re-introduce phy gates either by
> abusing clk gates or some other way. But they will depend on existing
> OF nodes.
> 
> Considering this, it would be best to fork kirkwood.dtsi for Prestera
> and leave out all OF nodes that are not implemented there. We could
> have
> 
> kirkwood.dtsi -+-> kirkwood-kirkwood.dtsi -+-> kirkwood-6281.dtsi
>                +-> kirkwood-prestera.dtsi  +-> kirkwood-6282.dtsi

or,

kirkwood.dtsi
prestera.dtsi

-pinctrl-
kirkwood-98dx4122.dtsi (should rename to prestera-, but seems churn-ish)
kirkwood-6281.dtsi
kirkwood-6282.dtsi

-dts-
kirkwood-km_kirkwood.dts (rename/churn prestera-?)
  |-prestera.dtsi
  \-kirkwood-98dx4122.dtsi

or, honestly, how many boards are going to be based on prestera?  If
it's just the one, why not combine all the nodes into
kirkwood-km_kirkwood.dts?


thx,

Jason.