Re: [PATCH v11 5/5] powerpc: Fix up fsl-flexcan device tree binding.

On Wed, Aug 10, 2011 at 12:36:22PM -0500, Scott Wood wrote:

On 08/10/2011 12:19 PM, Robin Holt wrote:

quoted

On Wed, Aug 10, 2011 at 11:56:28AM -0500, Scott Wood wrote:

quoted

On 08/10/2011 11:27 AM, Robin Holt wrote:

quoted

-CPI Clock- Can Protocol Interface Clock
-	This CLK_SRC bit of CTRL(control register) selects the clock source to
-	the CAN Protocol Interface(CPI) to be either the peripheral clock
-	(driven by the PLL) or the crystal oscillator clock. The selected clock
-	is the one fed to the prescaler to generate the Serial Clock (Sclock).
-	The PRESDIV field of CTRL(control register) controls a prescaler that
-	generates the Serial Clock (Sclock), whose period defines the
-	time quantum used to compose the CAN waveform.
+- compatible : Should be "fsl,flexcan" and optionally
+               "fsl,flexcan-<processor>"

fsl,<processor>-flexcan, and it should not be optional, and should come
before "fsl,flexcan".

Also may want to list fsl,p1010-rdb as a "canonical compatible" for
anything which is backwards compatible with p1010's implementation.

How do I specify 'canonical compatible'?

Something like:

  compatible: Should be "fsl,<processor>-flexcan" and "fsl,flexcan".

  An implementation should also claim any of the following compatibles
  that it is fully backwards compatible with:

  - fsl,p1010-rdb

I am so confused.  fsl,p1010-flexcan refers, in my mind at least, to
a particular chiplet on the p1010 freescale processor.  fsl,p1010-rdb
would mean nothing to me as that is a p1010 processor with two flexcan
chiplets wired to a pair of DB-9 jacks.  For the driver, what additional
information is being conveyed?

Let's cut to the chase.  Here is what I have after incorporating your
earlier comment about the compatible line.  Please mark this up to
exactly what you are asking for.

Thanks,
Robin
------------------------------------------------------------------------
Flexcan CAN contoller on Freescale's ARM and PowerPC processors

Required properties:

- compatible : Should be "fsl,<processor>-flexcan" and "fsl,flexcan"
- reg : Offset and length of the register set for this device
- interrupts : Interrupt tuple for this device

Example:

  can@1c000 {
          compatible = "fsl,p1010-flexcan", "fsl,flexcan";
          reg = <0x1c000 0x1000>;
          interrupts = <48 0x2>;
          interrupt-parent = <&mpic>;
  };