Re: AM335x OMAP2 common clock external fixed-clock registration

From: Tero Kristo
Date: Wed Apr 15 2015 - 14:43:33 EST

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:

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:

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.


+ 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>;
+ };
+ };


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

Whilest debugging I found that the of_clk_get is returning an error no matter
which clock I pass it:


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