From patchwork Tue Sep 25 14:32:19 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Linus Walleij X-Patchwork-Id: 974454 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=linux-gpio-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=linaro.org Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=linaro.org header.i=@linaro.org header.b="WLm9bszr"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 42KNnq6bxwz9s47 for ; Wed, 26 Sep 2018 00:32:31 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729317AbeIYUkQ (ORCPT ); Tue, 25 Sep 2018 16:40:16 -0400 Received: from mail-lj1-f193.google.com ([209.85.208.193]:38385 "EHLO mail-lj1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729188AbeIYUkP (ORCPT ); Tue, 25 Sep 2018 16:40:15 -0400 Received: by mail-lj1-f193.google.com with SMTP id p6-v6so21961655ljc.5 for ; Tue, 25 Sep 2018 07:32:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id; bh=U4y6ZtputpXJXWyhFUlFmPRAtoxRofEKwhSqArkgoLA=; b=WLm9bszrOwvsEjfs/3m34sOYZNZVbZyp2pnRx+zS1orGMnW3lV7JxktGgi0xrsDG+0 JpiDlwjK+/O4Ihh0+tZhMPU2YqIngeUBKSMzp7ywDLm2KeYRz1SRSD4BTZHmPAMj6v7l phEKWDI/T9578E8KlP+13sXTtJDvUcxuR10Kc= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=U4y6ZtputpXJXWyhFUlFmPRAtoxRofEKwhSqArkgoLA=; b=cYatyGeipDZu/vA/VNfjtTnN8N5pQEparz96SfOaKlsD6UO+9zriJLdUKL6JkE5X1C FO1JQkWBRWnstTXI9egfPhVZfCm+hb2E+JtiZHx4n3thIySk56XaNdeGa0eSPxTVQWX9 Gj59IxieN7uKv+aJLQZ4d0ZXYIg7jeBf/3lP9dYY+/wbOucqB07cZQQOuQ24rhEHbV+e VeLVAlNePsq/c08FTgENVtwh0ykVhwAG8knVu62WAhUekbsQ7rl+YSQDXGl+wSoic1/P zVWIJMTsEd5TG7YqPHwoATd8KRif6jAYjRWzbpFdbk7FQDUBW6GAx7LjGYB0JJT5SJcI voPA== X-Gm-Message-State: ABuFfog1H2DsR+L0xmNj1wWKuuGAxQ9iYBJiqG+yiZC3noPvSL14f6Td biN4iBTR0veF8o3FeD206qu7mg== X-Google-Smtp-Source: ACcGV61JD9mUHRW4/RLz8NCe3kdz5MMbHz+dgEQaaqkcWwSX1HMPT5n4fHrpdcBS9c393MJ7t4tQlA== X-Received: by 2002:a2e:900a:: with SMTP id h10-v6mr1090723ljg.121.1537885947316; Tue, 25 Sep 2018 07:32:27 -0700 (PDT) Received: from localhost.bredbandsbolaget (c-ae7b71d5.014-348-6c756e10.bbcust.telenor.se. [213.113.123.174]) by smtp.gmail.com with ESMTPSA id d13-v6sm441020lfi.74.2018.09.25.07.32.25 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 25 Sep 2018 07:32:25 -0700 (PDT) From: Linus Walleij To: Mark Brown , linux-spi@vger.kernel.org, Andrzej Hajda , Lorenzo Bianconi Cc: linux-gpio@vger.kernel.org, Linus Walleij , devicetree@vger.kernel.org Subject: [PATCH 1/2] spi: Add a DT binding for high-impedance turn-around Date: Tue, 25 Sep 2018 16:32:19 +0200 Message-Id: <20180925143220.19007-1-linus.walleij@linaro.org> X-Mailer: git-send-email 2.17.1 Sender: linux-gpio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org Some 3WIRE SPI devices require the host to insert a "high-impedance turn-around" essentially a clock pulse after switching the one line from output to input. This is needed to support the TPO TPG110 panel to use the 3WIRE SPI bindings. Cc: devicetree@vger.kernel.org Cc: Andrzej Hajda Cc: Lorenzo Bianconi Signed-off-by: Linus Walleij --- ChangeLog v1->v2: - Change some spelling, instert dash in high-impedance use turn-around instead of turnaround. --- Documentation/devicetree/bindings/spi/spi-bus.txt | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/Documentation/devicetree/bindings/spi/spi-bus.txt b/Documentation/devicetree/bindings/spi/spi-bus.txt index 1f6e86f787ef..d0b2d88a20ee 100644 --- a/Documentation/devicetree/bindings/spi/spi-bus.txt +++ b/Documentation/devicetree/bindings/spi/spi-bus.txt @@ -70,6 +70,10 @@ All slave nodes can contain the following optional properties: - spi-cs-high - Empty property indicating device requires chip select active high. - spi-3wire - Empty property indicating device requires 3-wire mode. +- spi-3wire-high-impedance-turn-around - Empty property indicating that a + 3wire host need to insert a high-impedance turn-around + clock cycle after turning the one output line into an + input line. - spi-lsb-first - Empty property indicating device requires LSB first mode. - spi-tx-bus-width - The bus width (number of data wires) that is used for MOSI. Defaults to 1 if not present.