Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031654AbcCQRAT (ORCPT ); Thu, 17 Mar 2016 13:00:19 -0400 Received: from devils.ext.ti.com ([198.47.26.153]:56841 "EHLO devils.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935821AbcCQRAN (ORCPT ); Thu, 17 Mar 2016 13:00:13 -0400 Subject: Re: [PATCH 4/5] pwm: pwm-tipwmss: Update documentation to use empty range property To: Rob Herring References: <1457380318-15452-1-git-send-email-fcooper@ti.com> <1457380318-15452-5-git-send-email-fcooper@ti.com> <20160317150140.GA25775@rob-hp-laptop> CC: , , , , , , , , , , , , , , , , From: "Franklin S Cooper Jr." Message-ID: <56EAE1BD.9040601@ti.com> Date: Thu, 17 Mar 2016 11:56:29 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1 MIME-Version: 1.0 In-Reply-To: <20160317150140.GA25775@rob-hp-laptop> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2313 Lines: 56 On 03/17/2016 10:01 AM, Rob Herring wrote: > On Mon, Mar 07, 2016 at 01:51:57PM -0600, Franklin S Cooper Jr wrote: >> Since the PWMSS and its subdevices (eCAP and ePWM) use the same address >> space then the range property should be empty. Update the documentation >> to show the correct usage. > Why does it matter? An empty ranges is generally not preferred. Someone pointed out that ranges should probably be empty. I double checked it with what is in the ePAPR doc and based on the definition it should be set to empty. I also checked against the am33xx.dtsi and saw that both USB and ethernet uses an empty value for ranges. Can you elaborate on why this isn't preferable? > >> Signed-off-by: Franklin S Cooper Jr >> --- >> Documentation/devicetree/bindings/pwm/pwm-tipwmss.txt | 12 ++++-------- >> 1 file changed, 4 insertions(+), 8 deletions(-) >> >> diff --git a/Documentation/devicetree/bindings/pwm/pwm-tipwmss.txt b/Documentation/devicetree/bindings/pwm/pwm-tipwmss.txt >> index f7eae77..672fa71 100644 >> --- a/Documentation/devicetree/bindings/pwm/pwm-tipwmss.txt >> +++ b/Documentation/devicetree/bindings/pwm/pwm-tipwmss.txt >> @@ -7,11 +7,9 @@ Required properties: >> Should set to 1. >> - size-cells: specify number of u32 entries needed to specify child nodes size >> in reg property. Should set to 1. >> -- ranges: describes the address mapping of a memory-mapped bus. Should set to >> - physical address map of child's base address, physical address within >> - parent's address space and length of the address map. For am33xx, >> - 3 set of child register maps present, ECAP register space, EQEP >> - register space, EHRPWM register space. >> +- ranges: describes the address mapping of a memory-mapped bus. Its value >> + should be empty since no address translation is needed between the >> + parent and the child. >> >> Also child nodes should also populated under PWMSS DT node. >> >> @@ -23,9 +21,7 @@ pwmss0: pwmss@48300000 { >> #address-cells = <1>; >> #size-cells = <1>; >> status = "disabled"; >> - ranges = <0x48300100 0x48300100 0x80 /* ECAP */ >> - 0x48300180 0x48300180 0x80 /* EQEP */ >> - 0x48300200 0x48300200 0x80>; /* EHRPWM */ >> + ranges; >> >> /* child nodes go here */ >> }; >> -- >> 2.7.0 >>