From patchwork Thu Jun 30 03:54:27 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Pronin X-Patchwork-Id: 9206605 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 116CD60752 for ; Thu, 30 Jun 2016 03:56:22 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0296A2859C for ; Thu, 30 Jun 2016 03:56:22 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id E898E28655; Thu, 30 Jun 2016 03:56:21 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,T_DKIM_INVALID autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B98F72859C for ; Thu, 30 Jun 2016 03:56:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751917AbcF3DzR (ORCPT ); Wed, 29 Jun 2016 23:55:17 -0400 Received: from mail-pa0-f53.google.com ([209.85.220.53]:36419 "EHLO mail-pa0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751698AbcF3Dyr (ORCPT ); Wed, 29 Jun 2016 23:54:47 -0400 Received: by mail-pa0-f53.google.com with SMTP id wo6so23916560pac.3 for ; Wed, 29 Jun 2016 20:54:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=QioMLUBad80Rhpw5LhqkI9SzPJtzZag7F5Jjb8X5dLY=; b=LSYirIzeF3MFOITRGK3C2We8yIcXClNAOkJXbe2D0+fzttal8i8Uky+nz+Zqk8lW84 91bk3vZj7mlI99Zelhs/69wl1vDlb8NogGltYkkZW9mSFRQC1tYZ+9jyH4OT1uN3iFvw rzNVUXGHYnfOc23NZg7qPh6rsDE7h1iEKQs4s= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=QioMLUBad80Rhpw5LhqkI9SzPJtzZag7F5Jjb8X5dLY=; b=P0dhFlvWwTsP7lQ7KKqAV0IZ9OeMvvu4yxmFnqoNO+XyN1GmRv1mtkrdEWcxKrCg96 jJ03dVm5B7LzeXem/d2TuNsev0UiBxuZj29rt7D4/b9MqEwTNHOwp+03wtPQUluoenh7 i6qLCW0dQyNO0VO5sKWqG7S4mBmFkyH7OX1IMdx81e4yRH87/kF5oHp6h5Xh3aCrUCJU ZiaF0VcwEjrI/PpBf9x4c1g6T6a21MnEXUfOMXTNXFmV0Y6f7gqEiJ941trGjet5Y0mv q2Seu/Tl+mo9RpK2BBIR5SlBQFk1vpxi3TdZdgwnkJJ5VbHPRdfdGnaSAZqnn9N/oROE s8mA== X-Gm-Message-State: ALyK8tI3a/JxaplktPQk3fYQpYXA7PP/U2+Andop3Jhgo5ofc6ibYKL1JUWpPRykh52FNSeq X-Received: by 10.66.216.8 with SMTP id om8mr17910926pac.9.1467258871155; Wed, 29 Jun 2016 20:54:31 -0700 (PDT) Received: from apronin0.mtv.corp.google.com ([172.22.64.136]) by smtp.gmail.com with ESMTPSA id 64sm1184045pfj.96.2016.06.29.20.54.30 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Wed, 29 Jun 2016 20:54:30 -0700 (PDT) From: apronin@chromium.org To: Mark Brown Cc: linux-kernel@vger.kernel.org, linux-spi@vger.kernel.org, Andrey Pronin Subject: [PATCH 4/4] spi: Document option to insert delay between transactions Date: Wed, 29 Jun 2016 20:54:27 -0700 Message-Id: <1467258867-117727-4-git-send-email-apronin@chromium.org> X-Mailer: git-send-email 2.8.0.rc3.226.g39d4020 In-Reply-To: <1467258867-117727-1-git-send-email-apronin@chromium.org> References: <1467258867-117727-1-git-send-email-apronin@chromium.org> Sender: linux-spi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Andrey Pronin Some devices may need CS to be deasserted for some time between transactions. Added a new capability to guarantee a delay between SPI transactions for the device. Signed-off-by: Andrey Pronin --- Documentation/devicetree/bindings/spi/spi-bus.txt | 2 ++ 1 file changed, 2 insertions(+) diff --git a/Documentation/devicetree/bindings/spi/spi-bus.txt b/Documentation/devicetree/bindings/spi/spi-bus.txt index 1b7ffd4..87c117a 100644 --- a/Documentation/devicetree/bindings/spi/spi-bus.txt +++ b/Documentation/devicetree/bindings/spi/spi-bus.txt @@ -70,6 +70,8 @@ contain the following properties. sleep if there was no SPI activity (msec). - cs-wake-duration - (optional) Time it takes the device to wake up after toggling CS if it went to sleep (msec). +- xfer-delay - (optional) Delay to insert between SPI transactions + to guarantee that CS is deasserted at least for some time. Some SPI controllers and devices support Dual and Quad SPI transfer mode. It allows data in the SPI system to be transferred in 2 wires(DUAL) or 4 wires(QUAD).