Re: AM335x OMAP2 common clock external fixed-clock registration

[Tero Kristo]

On 04/15/2015 05:09 PM, Michael Welling wrote:
> On Wed, Apr 15, 2015 at 09:34:48AM +0300, Tero Kristo wrote:
> > On 04/15/2015 12:17 AM, Michael Welling wrote:
> > > Greetings,
> > >
> > > I have developed an AM3354 based SoM and it uses an external SI5351 clock
> > > generator to drive the clock inputs for an external duart and I2S audio
> > > master clock. With the registration according to the documentation the
> > > reference clock is not being detected and hence the clock generator is
> > > not working as expect.
> > >
> > > After trying many different things, I started to look around the mailing
> > > lists to find information related to this issue.
> > >
> > > I came acrossed post that has the exact same issue:
> > > https://lkml.org/lkml/2013/2/18/468
> > >
> > > Seeing as the patch did not land upstream, I am wondering if there is
> > > a solution that I am not seeing.
> > >
> > > I am willing to provide a patch given appropriate guidance.
> >
> > Hi Michael,
> >
> > The info on the email you referenced is kind of obsolete, TI SoCs
> > are calling of_clk_init() during boot now, and thus external clock
> > nodes should be registered fine also. Maybe you can provide the
> > actual DTS patch you are trying out so we can help better...? Are
>
> See attached patch and console output.

I see a bug in your dt data.

<snip>

+	clocks {
+		ref27: ref27 {
+			#clock-cells = <0>;
+			compatibale = "fixed-clock";

This should be compatible, right? DT is annoying in that it doesn't 
verify property names.

+			clock-frequency = <27000000>;
+		};
+	};

-Tero

> > you seeing any boot time error / warning prints for your new clock?
>
> With the debug messages on you see that the reference clock is not being
> detected.
>
> Whilest debugging I found that the of_clk_get is returning an error no matter
> which clock I pass it:
> http://lxr.free-electrons.com/source/drivers/clk/clk-si5351.c#L1131
>
> > -Tero

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