Re: [PATCH V2 4/5] gpio: DT: Rephrase "gpios" of hog node to support multiple gpios

From: Stephen Warren
Date: Tue Mar 15 2016 - 11:40:25 EST

On 03/15/2016 12:37 AM, Laxman Dewangan wrote:

On Monday 14 March 2016 10:01 PM, Stephen Warren wrote:
On 03/11/2016 06:43 AM, Laxman Dewangan wrote:
The property "gpios" of GPIO hog node support the multiple GPIO entries.
Rephrase the details of this property for this new support.

Add details of new property "label" for GPIO label name.

diff --git a/Documentation/devicetree/bindings/gpio/gpio.txt

Optional properties:
- line-name: The GPIO label name. If not present the node name is
+- label: The GPIO lable name. This can have multiple string for
+ label names to match with the GPIOs in "gpios" properties.
+ If line-name is prosent than name is taken from line-name. If
+ it is not then the name will be taken from label. If both are
+ not available then node name is used for GPIO label name.

Why are there two properties for the same thing? Why not just allow
line-name to have multiple entries instead of introducing a new property?

We can use the lin-names also but per disucssion on the patch V1 of
gpio: of: Add support to have multiple gpios in gpio-hog

Markus suggested the discussion about the discussion
"Device tree binding documentation for gpio-switch"

and on that, label is used. Also for names, "label" is going to very

So I added new property "label" to support multiple names.

It makes sense to standardize on a common name for new bindings, but this binding has already picked a name. It'd be much simpler for anyone looking at the binding (and backwards-compatibility) to just stick with it. We have to support the old name forever no matter what. Supporting two different names will just be confusing.