From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753220AbbJWLvz (ORCPT ); Fri, 23 Oct 2015 07:51:55 -0400 Received: from mail.kernel.org ([198.145.29.136]:49235 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751920AbbJWLvx (ORCPT ); Fri, 23 Oct 2015 07:51:53 -0400 MIME-Version: 1.0 In-Reply-To: <3735458.2h6HCQhAOs@avalon> References: <1445233398-27129-1-git-send-email-pramodku@broadcom.com> <56293052.80402@broadcom.com> <3735458.2h6HCQhAOs@avalon> From: Rob Herring Date: Fri, 23 Oct 2015 06:51:28 -0500 Message-ID: Subject: Re: [PATCH 05/11] dt-binding: Add ngpios property to GPIO controller node To: Laurent Pinchart Cc: Ray Jui , Pramod Kumar , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , Scott Branden , Russell King , Linus Walleij , "linux-gpio@vger.kernel.org" , BCM Kernel Feedback , Jason Uy , Masahiro Yamada , Thomas Gleixner , "devicetree@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Jonas Gorski Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 >> >>> 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 ? 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. Rob