Subject: UCC UART

From: Gary Thomas <[email-masked]>
Date: Tue, 22 Jun 2010 08:55:07 -0600

I'm still trying to get UCC UART to work on my MPC8358 with
the 2.6.33.3 kernel.

When I try to send data to the port, there is no output, not
even any interrupts on the device.  What I see is that the UART
driver seems to initialize fine and pushes characters into
the output buffers & descriptors.  However, there are no
interrupts hence it just sits there...

My device tree entry for this device now looks like this:
	/* ttyQE0 (UCC3) */
	serial_qe0: serial@4000 {
                 device_type = "serial";
                 compatible = "ucc_uart";
                 cell-index = <3>;
		reg = <0x2200 0x200>;
		interrupts = <34>;
		interrupt-parent = <&qeic>;
                 port-number = <0>;
		rx-clock-name = "brg1";
		tx-clock-name = "brg1";
	};

* Are there any known issues with this driver?
* Is there any way to get a handle on why no data is moving?
* Is there some way to tell if the QE even sees the descriptors?
* The driver and documentation mention a "soft UART" mode for
   chips with broken UART hardware.  How do I know if my board
   has functioning UART hardware?

Note: I have UCC1+UCC2 working great with ethernet.

Thanks for any pointers or ideas

-- 
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Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
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