From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 644B5C46460 for ; Tue, 14 Aug 2018 20:27:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1FAA921725 for ; Tue, 14 Aug 2018 20:27:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1FAA921725 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729609AbeHNXQP (ORCPT ); Tue, 14 Aug 2018 19:16:15 -0400 Received: from mail-pl0-f52.google.com ([209.85.160.52]:42655 "EHLO mail-pl0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727755AbeHNXQP (ORCPT ); Tue, 14 Aug 2018 19:16:15 -0400 Received: by mail-pl0-f52.google.com with SMTP id g6-v6so8763811plq.9; Tue, 14 Aug 2018 13:27:23 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to:user-agent; bh=1NfZBWI5tH2sZprHouPh7mwAwhT6001VDTBSRWtlnuQ=; b=Ok1NM7kW7JfgCO6EgYj4NKMfWd0sasjZt+VB8bWhjpvjHepNazu2V4ysJWYZwGDQp+ VgDslblC0lZ7Zo6GiLVXtVLhiqQDrN2BgHS1zpHk0vw81Nc1pienNI/3vN9Revn1lEEY EyfGC5XyQPvVUcCsKo9Yz8kJzS049HqNVydbP1/etUKTcaeUrT9afYItUmspb5UqWNFg 8Os5TnQ58kpmkfiAhzy6Z8rlF3fHHr+jN3p6UmRrzazPAaNal9XRBtaLcxhG6h2aRg/7 m72d/DomOPXY80nqqVEbShAsArIIwh/Lr8brStnyvfR1/XCRINiNygWHtacNfHF2Wbgw +/bQ== X-Gm-Message-State: AOUpUlGtkl2dbm3ZtSMwxzRBRpzC3h74GhTedunwqnFK7yLRRElf2+EA dv6JzrhARCEFvd3qBWH9JQ== X-Google-Smtp-Source: AA+uWPz2rigwXLBF2U5NU9ghM2u7KwZetFgr5sQtGwXc197nv55dW/bAze9gTfPNA+AVrojw5RIUSA== X-Received: by 2002:a17:902:bc8b:: with SMTP id bb11-v6mr21369644plb.112.1534278442834; Tue, 14 Aug 2018 13:27:22 -0700 (PDT) Received: from localhost ([74.118.88.158]) by smtp.gmail.com with ESMTPSA id a17-v6sm32131965pfg.106.2018.08.14.13.27.21 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 14 Aug 2018 13:27:22 -0700 (PDT) Date: Tue, 14 Aug 2018 14:27:20 -0600 From: Rob Herring To: Baolin Wang Cc: Trent Piepho , "broonie@kernel.org" , "linux-kernel@vger.kernel.org" , "orsonzhai@gmail.com" , "devicetree@vger.kernel.org" , "zhang.lyra@gmail.com" , "mark.rutland@arm.com" , "linux-spi@vger.kernel.org" , "lanqing.liu@spreadtrum.com" Subject: Re: [PATCH 1/2] dt-bindings: spi: Add Spreadtrum SPI controller documentation Message-ID: <20180814202720.GB26606@rob-hp-laptop> References: <64681bf903104c8a02f118294e616e2a12a5ebe4.1533638405.git.baolin.wang@linaro.org> <20180807134121.GA7958@sirena.org.uk> <20180808095025.GB9346@sirena.org.uk> <20180808105451.GE9346@sirena.org.uk> <1533754621.2283.270.camel@impinj.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 09, 2018 at 11:03:11AM +0800, Baolin Wang wrote: > Hi Trent, > > On 9 August 2018 at 02:57, Trent Piepho wrote: > > On Wed, 2018-08-08 at 11:54 +0100, Mark Brown wrote: > >> On Wed, Aug 08, 2018 at 06:35:28PM +0800, Baolin Wang wrote: > >> > On 8 August 2018 at 17:50, Mark Brown wrote: > >> > > Right, I don't think we added this yet (if we did I can't see > >> > > it). I'd > >> > > add a new field to spi_transfer for this, then other controllers > >> > > with > >> > > the same support can implement it as well and drivers can start > >> > > using > >> > > it too. > >> > OK. So I will name the new filed as 'word_delay', is it OK for you? > >> > >> Sounds good, yes. > > > > Should it be in µs like the existing iter-transfer delay? I think > > perhaps units of cycles of the SPI clock make more sense? > > Since some SPI controllers just want some interval values (neither µs > unit nor cycles unit ) set into hardware, and the hardware will > convert to the correct delay time automatically. So I did not force > 'word_delay' unit as µs or cycle, and just let the slave devices > decide the unit which depends on the SPI hardware requirement. This needs to be defined units in DT, not decided by each controller. The controller capabilities just affect what are valid values (or what the resolution is). Rob