From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Warren Subject: Re: How to represent negative values for device tree property Date: Mon, 01 Apr 2013 16:00:47 -0600 Message-ID: <515A038F.2090902@wwwdotorg.org> References: <5159F760.1080605@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: Received: from avon.wwwdotorg.org ([70.85.31.133]:57538 "EHLO avon.wwwdotorg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753929Ab3DAWAt (ORCPT ); Mon, 1 Apr 2013 18:00:49 -0400 In-Reply-To: <5159F760.1080605@codeaurora.org> Sender: linux-arm-msm-owner@vger.kernel.org List-Id: linux-arm-msm@vger.kernel.org To: David Collins Cc: devicetree-discuss@lists.ozlabs.org, linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org On 04/01/2013 03:08 PM, David Collins wrote: > Hi, > > I am working on a thermal driver which needs to be able to read a > temperature threshold from a device tree property. The hardware supports > thresholds in the range -204.8 to +204.7 C in 0.1 C steps. I have found, > as I am sure others have as well, that dtc treats a '-' before an integer > in a dtsi file as a syntax error. Therefore, I need some artificial way > to represent negative numbers in device tree. Here are the possibilities > that I have thought of so far: Doesn't the very latest dtc, which contains integer expression support, allow unary -? I thought that code had been imported into the kernel (goes and checks) yes it has. What's the error you're seeing; over/underflow or syntax? That said, DT cells are supposed to be u32 not s32, so perhaps this isn't unexpected. From mboxrd@z Thu Jan 1 00:00:00 1970 From: swarren@wwwdotorg.org (Stephen Warren) Date: Mon, 01 Apr 2013 16:00:47 -0600 Subject: How to represent negative values for device tree property In-Reply-To: <5159F760.1080605@codeaurora.org> References: <5159F760.1080605@codeaurora.org> Message-ID: <515A038F.2090902@wwwdotorg.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 04/01/2013 03:08 PM, David Collins wrote: > Hi, > > I am working on a thermal driver which needs to be able to read a > temperature threshold from a device tree property. The hardware supports > thresholds in the range -204.8 to +204.7 C in 0.1 C steps. I have found, > as I am sure others have as well, that dtc treats a '-' before an integer > in a dtsi file as a syntax error. Therefore, I need some artificial way > to represent negative numbers in device tree. Here are the possibilities > that I have thought of so far: Doesn't the very latest dtc, which contains integer expression support, allow unary -? I thought that code had been imported into the kernel (goes and checks) yes it has. What's the error you're seeing; over/underflow or syntax? That said, DT cells are supposed to be u32 not s32, so perhaps this isn't unexpected.