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=-2.4 required=3.0 tests=DKIM_SIGNED, MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID,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 36FCCC46470 for ; Wed, 8 Aug 2018 09:50:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D791521725 for ; Wed, 8 Aug 2018 09:50:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=sirena.org.uk header.i=@sirena.org.uk header.b="DBbTkO1W" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D791521725 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 S1726996AbeHHMJb (ORCPT ); Wed, 8 Aug 2018 08:09:31 -0400 Received: from heliosphere.sirena.org.uk ([172.104.155.198]:46164 "EHLO heliosphere.sirena.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726542AbeHHMJb (ORCPT ); Wed, 8 Aug 2018 08:09:31 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sirena.org.uk; s=20170815-heliosphere; h=In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=lyOh+E51IkJJarEp/Q6nRP0TBLHGLto+TqcobvCpjvI=; b=DBbTkO1WwovOmeiOEKYr+acum x1I3NgmOzf5txSYHX4JL5hqeVSyKjzJ1sFtkZntxWu5yDUQgYNcatg6NecYotYx0D93IGHpyV/dEu Ow/qCWw2mogWGV3ZUZiEVt8ObZCkGSx3hE71ZGc680GJ6cMOFyJCcKeoe8DgBmHCk3F0U=; Received: from cpc102320-sgyl38-2-0-cust46.18-2.cable.virginm.net ([82.37.168.47] helo=debutante.sirena.org.uk) by heliosphere.sirena.org.uk with esmtpa (Exim 4.89) (envelope-from ) id 1fnL6o-0001ex-Bw; Wed, 08 Aug 2018 09:50:26 +0000 Received: by debutante.sirena.org.uk (Postfix, from userid 1000) id EB3AF112433B; Wed, 8 Aug 2018 10:50:25 +0100 (BST) Date: Wed, 8 Aug 2018 10:50:25 +0100 From: Mark Brown To: Baolin Wang Cc: Rob Herring , Mark Rutland , Orson Zhai , Chunyan Zhang , lanqing.liu@spreadtrum.com, linux-spi@vger.kernel.org, DTML , LKML Subject: Re: [PATCH 1/2] dt-bindings: spi: Add Spreadtrum SPI controller documentation Message-ID: <20180808095025.GB9346@sirena.org.uk> References: <64681bf903104c8a02f118294e616e2a12a5ebe4.1533638405.git.baolin.wang@linaro.org> <20180807134121.GA7958@sirena.org.uk> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="KFztAG8eRSV9hGtP" Content-Disposition: inline In-Reply-To: X-Cookie: Should I do my BOBBIE VINTON medley? User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --KFztAG8eRSV9hGtP Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Wed, Aug 08, 2018 at 10:26:42AM +0800, Baolin Wang wrote: > Sorry for confusing. Let me try to explain it explicitly. > We can set the word size (bits_per_word) for each transmission, for > our SPI controller, after every word size transmission, we need one > interval time (hardware automatically) to make sure the slave has > enough time to receive the whole data. OK, so it's an inter word delay. Some other controllers definitely have the same feature. > Yes, I agree we should configure it at runtime by the device, but we > did not find one member to use in 'struct spi_transfer', we just find > one similar 'delay_usecs' member in 'struct spi_transfer' but not > same. We can use 'delay_usecs' to set our hardware interval value, > but we should clean it when transfer is done, since we do not need to > delay after the transfer in spi_transfer_one _message(). Or can we add > one new member maybe named 'word_interval' to indicate the interval > time between word size transmission? 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. --KFztAG8eRSV9hGtP Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAltqvOEACgkQJNaLcl1U h9CY0Af/eBUJ7rNaApVEZ8zpR9awGuzC9IkLgzgDsXKKYPO7657rD75vSDe7NhbK s+qaczqcFz7hBawHtE8wHyZP4WRyDVp5H7RiFxQ1XWCG8Sj31l3sEEXtNC3BuvLn 6sS+pqWgyyElqcyrysHOnqam2EI6VyMUTq2mNFSu+Z5GIAzMYtsQhg39aNbsG70E F3xh/Wn84anaLdYqt+2kjLoD1FaS2snHcFWRAH7sop+bz7vzd02lDeczUOOPbdFT sQ+33BqFpVb6wOaPP+lkOrACkoi0wIbHzfkZZifJ6olGqxlQpELH4hjP8M8zrXqa rzHzUapZ1Duu7QuW0UyTQ/lgPtSFuw== =vp/V -----END PGP SIGNATURE----- --KFztAG8eRSV9hGtP--