Hi Rob, On Friday 23 October 2015 06:51:28 Rob Herring wrote: > On Fri, Oct 23, 2015 at 4:08 AM, Laurent Pinchart wrote: > > On Thursday 22 October 2015 18:41:05 Rob Herring wrote: > >> On Thu, Oct 22, 2015 at 1:52 PM, Ray Jui wrote: > >>> On 10/22/2015 11:43 AM, Rob Herring wrote: > >>>> On Mon, Oct 19, 2015 at 12:43 AM, Pramod Kumar wrote: > >>>>> Add ngpios property to the gpio controller's DT node so that > >>>>> controller driver extracts total number of gpio lines present in > >>>>> controller from DT and removes dependency on driver. > >>>>> > >>>>> Signed-off-by: Pramod Kumar <pramodku@xxxxxxxxxxxx> > >>>>> Reviewed-by: Ray Jui <rjui@xxxxxxxxxxxx> > >>>>> Reviewed-by: Scott Branden <sbranden@xxxxxxxxxxxx> > >>>>> --- > >>>>> > >>>>> Documentation/devicetree/bindings/pinctrl/brcm,cygnus-gpio.txt | 5 > >>>>> +++ > >>>>> 1 file changed, 5 insertions(+) > >>>>> > >>>>> diff --git > >>>>> a/Documentation/devicetree/bindings/pinctrl/brcm,cygnus-gpio.txt > >>>>> b/Documentation/devicetree/bindings/pinctrl/brcm,cygnus-gpio.txt > >>>>> index f92b833..655a8d7 100644 > >>>>> --- a/Documentation/devicetree/bindings/pinctrl/brcm,cygnus-gpio.txt > >>>>> +++ b/Documentation/devicetree/bindings/pinctrl/brcm,cygnus-gpio.txt > >>>>> > >>>>> @@ -10,6 +10,9 @@ Required properties: > >>>>> Define the base and range of the I/O address space that > >>>>> contains > >>>>> > >>>>> the Cygnus > >>>>> > >>>>> GPIO/PINCONF controller registers > >>>>> > >>>>> +- ngpios: > >>>> + Total number of GPIOs the controller provides > >>>> > >>>> This must be optional for compatibility and the driver needs to handle > >>>> it not present. > >>> > >>> You meant to be compatible with existing Cygnus devices, correct? > >>> > >>> Just to clarify, here you suggest we still leave the existing hard > >>> coded ngpios in the driver, in order to be compatible with all existing > >>> Cygnus devices (while the Cygnus device tree changes to use ngpio is > >>> still being merged and through different maintainer), and have all new > >>> iProc SoCs switch to use ngpios from device tree, right? > >> > >> Yes, an existing dtb should continue to work with a new kernel. You > >> can add the DT property to the older devices too and then eventually > >> remove the hard coded values some time in the future. That could be > >> immediately (don't care about compatibility at all), a couple of > >> kernel cycles, never... It all depends on users of the impacted > >> platforms. > > > > But shouldn't the property still be documented as required to ensure that > > new DTs always include it ? > > Good point. If the intent is to eventually remove it from the driver, > then yes. We probably need "required for new designs" as a category or > maybe "recommended"? The wording is not so important here, but I'm > thinking about as we try to standardize the naming. Required for new designs sounds better than recommended. Or maybe something like "Required (optional for backward compatibility)". -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
