Re: [RFC] media DT bindings

[Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>]

On 07/31/2012 11:59 PM, Laurent Pinchart wrote:
> Hi Stephen,
> 
> On Tuesday 31 July 2012 17:29:24 Stephen Warren wrote:
>> On 07/31/2012 03:22 PM, Laurent Pinchart wrote:
>>> On Tuesday 31 July 2012 14:39:07 Guennadi Liakhovetski wrote:
>> ...
>>
>>>> Ok, then, how about
>>>>
>>>> 		#address-cells = <1>;
>>>> 		#size-cells = <0>;
>>>> 		...
>>>> 		ov772x-1 = {
>>>> 		
>>>> 			reg = <1>;			/* local pad # */
>>>> 			client = <&ov772x@0x21-0 0>;	/* remote phandle and pad */
>>>
>>> The client property looks good, but isn't such a usage of the reg property
>>> an abuse ? Maybe the local pad # should be a device-specific property.
>>> Many hosts won't need it, and on others it would actually need to
>>> reference a subdev, not just a pad.
>>
>> That's a very odd syntax the the phandle; I assume that "&ov772x@0x21-0"
>> is supposed to reference some other DT node. However, other nodes are
>> either referenced by:
>>
>> "&foo" where foo is a label, and the label name is unlikely to include
>> the text "@0x21"; the @ symbol probably isn't even legal in label names.
>>
>> "&{/path/to/node}" which might include the "@0x21" syntax since it might
>> be part of the node's name, but your example didn't include {}.
>>
>> I'm not sure what "-0" is meant to be in that string - a math
>> expression, or ...? If it's intended to represent some separate field
>> relative to the node the phandle references, it needs to be just another
>> cell.
> 
> I'm actually not sure what -0 represents, and I don't think we need the 
> @0x21-0 at all. I believe &ov772x@0x21-0 is supposed to just be a label. We 
> don't need an extra cell.

Ah, OK. The lexer in dtc has the following definition for label names:

LABEL		[a-zA-Z_][a-zA-Z0-9_]*