> -----Original Message----- > From: Ray Jui [mailto:rjui@xxxxxxxxxxxx] > Sent: 23 October 2015 21:38 > To: Laurent Pinchart; Rob Herring > Cc: Pramod Kumar; Pawel Moll; Mark Rutland; Ian Campbell; Kumar Gala; Scott > Branden; Russell King; Linus Walleij; linux-gpio@xxxxxxxxxxxxxxx; bcm-kernel- > feedback-list; Jason Uy; Masahiro Yamada; Thomas Gleixner; > devicetree@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux- > kernel@xxxxxxxxxxxxxxx; Jonas Gorski > Subject: Re: [PATCH 05/11] dt-binding: Add ngpios property to GPIO controller > node > > > > On 10/23/2015 6:02 AM, Laurent Pinchart wrote: > > 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)". > > > > Yes, it should be phrased as "required for new designs" because all new iProc > SoCs using this GPIO driver need to have this in DT. > > Thanks, > > Ray Thanks for providing feedback. I'll make sure to use this property under phrase " required for new designs " in next patch set. Regards, Pramod -- 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
