From mboxrd@z Thu Jan 1 00:00:00 1970 From: laurent.pinchart@ideasonboard.com (Laurent Pinchart) Date: Fri, 23 Oct 2015 12:08:50 +0300 Subject: [PATCH 05/11] dt-binding: Add ngpios property to GPIO controller node In-Reply-To: References: <1445233398-27129-1-git-send-email-pramodku@broadcom.com> <56293052.80402@broadcom.com> Message-ID: <3735458.2h6HCQhAOs@avalon> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 > >>> Reviewed-by: Ray Jui > >>> Reviewed-by: Scott Branden > >>> --- > >>> > >>> 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 ? -- Regards, Laurent Pinchart