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

On 08/10/2011 01:30 PM, Robin Holt wrote:

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

quoted

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

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

Gah, I don't know how "rdb" replaced "flexcan" in the above.  Sorry for
any confusion.

I am so confused.  fsl,p1010-flexcan refers, in my mind at least, to
a particular chiplet on the p1010 freescale processor. 

It refers to a particular version of the flexcan logic, for which the
hardware doc people weren't kind enough to give us a public version number.

It has been common and recommended practice in such cases, when there
are multiple chips containing the same device, to pick a canonical chip
(such as the first one to have the device or to be supported) and have
others claim compatibility with it.

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?

The programming model of the flexcan chiplet.

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"

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

   - fsl,p1010-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>;
  };

-Scott