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adv7511 on another fclk

Question asked by chadgentry on Jan 23, 2015
Latest reply on Feb 9, 2015 by chadgentry

I'm trying to incorporate the adv7511 mini-itx project with a pcore I bought from a 3rd party.  This core and associated Linux driver require that it use fclk0.  However, if I move all the adv7511 and associated pcores to another fclk, the hdmi to the monitor gets screwed up.  I get a picture but each row is misaligned with the row above it.  The picture is fine if I don't move the clocks.

 

My suspicion is that somewhere in Linux, it's expecting to use fclk0 and fclk1 to set up the HDMI transmit clock, but when it reads fclk0, it sees a frequency besides 100MHz and configures clkgen to generate a clock based on that.  I tried to specify the right clock in the devicetree (see below) but it seems to have no effect.

 

Here's my new system:

  • the 100MHz clock is now on fclk2
  • the 200MHz clock remained on fclk3
  • I changed the hdmi_clock devicetree entry to the following

hdmi_clock: axi-clkgen@83C00000 {

   compatible = "adi,axi-clkgen-2.00.a";

   reg = <0x83C00000 0x10000>;

   #clock-cells = <0>;

   clocks = <&clkc 18>;

};

 

I'm not really sure where to go from here.

 

Thanks,

Chad

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