Re: [v2, 1/4] ARM: davinci: da8xx-dt: Add ti-aemif lookup for clock matching

[David Lechner]

On 01/03/2017 02:58 AM, Sekhar Nori wrote:
> On Monday 02 January 2017 01:34 PM, Sekhar Nori wrote:
> > On Saturday 31 December 2016 06:22 AM, David Lechner wrote:
> > > On 08/10/2016 06:00 AM, Karl Beldan wrote:
> > > > Many davinci boards (da830 and da850 families) don't have their clocks
> > > > in DT yet and won't be successful in getting an unnamed aemif clock
> > > > without explicitly registering them via clk_lookups, failing the
> > > > ti-aemif memory driver probe.
> > > >
> > > > The current aemif lookup entry resolving to the same clock:
> > > >     'CLK(NULL,               "aemif",        &aemif_clk)'
> > > > remains, as it is currently used (davinci_nand is getting a named clock
> > > > "aemif").
> > > >
> > > > This change will allow to switch from the mach-davinci aemif code to
> > > > the ti-aemif memory driver.
> > > >
> > > > Signed-off-by: Karl Beldan <kbeldan@xxxxxxxxxxxx>
> > > > ---
> > >
> > > FYI, I can't boot LEGO MINDSTORMS EV3 (AM1908) with a v4.9 mainline
> > > kernel. I did a git bisect and traced it down to this patch. I'm
> > > guessing that simply reverting it will break other things.
> > >
> > > The problem is that &aemif_clk is a node in a linked list and points to
> > > itself, which creates an infinite loop when looking up the usb clocks
> > > that are later in the list.
> > >
> > > I thought there was a patch to fix this properly from one of the Bay
> > > Libre guys to fix this already, but I can't seem to find it at the
> > > moment. When it is found, it would be good to have it applied to the 4.9
> > > stable and 4.10 mainline trees.
> >
> > Yes, a patch was submitted. It is pending in my queue since I need to do
> > a few experiments myself to determine if its the best solution possible.
> > Thanks for the heads-up on need to mark it for v4.9 stable. Will do.
>
> The master branch of my tree should have the patch included. If you can
> test and confirm it works fine on the lego platform, it will be great.

Tested "ARM: davinci: da850: fix infinite loop in clk_set_rate()" 
working on LEGO Mindstorms with a 4.9.0 kernel.