From patchwork Sun Dec 17 12:20:03 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Winklhofer X-Patchwork-Id: 180002 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a05:7300:24d3:b0:fb:cd0c:d3e with SMTP id r19csp675609dyi; Sun, 17 Dec 2023 04:21:32 -0800 (PST) X-Google-Smtp-Source: AGHT+IGhfOcfl96/hIy6IHBuQMBJF99IslGpS2epm4fDSfsPVJxRDgUZg2YaPD1zUkkbiybwsxSb X-Received: by 2002:a05:6a21:19b:b0:194:425d:bda with SMTP id le27-20020a056a21019b00b00194425d0bdamr61038pzb.55.1702815692573; Sun, 17 Dec 2023 04:21:32 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1702815692; cv=none; d=google.com; s=arc-20160816; b=AtMpYD24z7UKKMv18df991paXHd2wf1IMXdssRK0sZFjOkBxXMDTnGJJ7Q4K599z5D TI1O4L1kJttXmDGJmlEbBgeDkluP6gfUOUZmrR9Zg7Hugi018As9Bxj1wW6UeRsN/Lvw B+O0gc0jUoMvkQq/SFSarT634ioiYYEbEAd4Y/qn6mdOOvKlJ2NvR98cK4Xgb+C9ZKUR BvlwbEMCBuam7CXY6BjVzTxZ76b3ymYFA48mVqc+OS88JKlE/zVtmzGXlV/kfJfF2tXZ sgFUchAEO5x/zQAfepYNc5SHB1KwBS0zj44f21OpcZJQMDEJBsltGMBmIFzP1ix7j2by 3tpA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-transfer-encoding:mime-version:list-unsubscribe :list-subscribe:list-id:precedence:references:in-reply-to:message-id :date:subject:cc:to:from:dkim-signature; bh=ASUrErE9IB4rBsV06LSlQI5+Mv2WPJpJ2KbkeexjDLU=; fh=EI065BL1O5Z7XQnp588pIE3j/TBmNqn9jjQVJsWdQuk=; b=MsolxIS3gH/do8of67ZTif3i88otoxvkqd6mEjEFbPgMYTI5AV3dJsI0xg7LW1N3C7 eMBcv2E/TpoKU0In8aQfJ9rMTE+FAVjzeBHFqCwanYFszcG7Rw6dITd86mV4h710KOoy uKclyxRcIvJy2yNbJjfJLheqMPp040/spGkD8YhV6zRHy8j+VK/SSW+R4XTXBVqCpSye 6vNQVuwMfBiFAhwU5rNHjWiFiwCbLrrTmdvTA3sKyEa1/2NXUG85apim4I+Hn97qAbAr IP2vB3lphe1nHal6Lk5niJHs1X0Jt3x9lU1QSwjMKhloBYDXC9HxDr0IJ6jL5tdPBZrh 0SJA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20230601 header.b=gU29NcpZ; spf=pass (google.com: domain of linux-kernel+bounces-2571-ouuuleilei=gmail.com@vger.kernel.org designates 147.75.48.161 as permitted sender) smtp.mailfrom="linux-kernel+bounces-2571-ouuuleilei=gmail.com@vger.kernel.org"; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: from sy.mirrors.kernel.org (sy.mirrors.kernel.org. [147.75.48.161]) by mx.google.com with ESMTPS id j4-20020a170902da8400b001cf6aac6b5fsi16260634plx.559.2023.12.17.04.21.32 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 17 Dec 2023 04:21:32 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel+bounces-2571-ouuuleilei=gmail.com@vger.kernel.org designates 147.75.48.161 as permitted sender) client-ip=147.75.48.161; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20230601 header.b=gU29NcpZ; spf=pass (google.com: domain of linux-kernel+bounces-2571-ouuuleilei=gmail.com@vger.kernel.org designates 147.75.48.161 as permitted sender) smtp.mailfrom="linux-kernel+bounces-2571-ouuuleilei=gmail.com@vger.kernel.org"; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: from smtp.subspace.kernel.org (wormhole.subspace.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sy.mirrors.kernel.org (Postfix) with ESMTPS id C7550B21D5E for ; Sun, 17 Dec 2023 12:21:27 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id AEEF135281; Sun, 17 Dec 2023 12:20:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="gU29NcpZ" X-Original-To: linux-kernel@vger.kernel.org Received: from mail-lj1-f170.google.com (mail-lj1-f170.google.com [209.85.208.170]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7B05432C63; Sun, 17 Dec 2023 12:20:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Received: by mail-lj1-f170.google.com with SMTP id 38308e7fff4ca-2cc5d9cf766so13552211fa.2; Sun, 17 Dec 2023 04:20:45 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1702815643; x=1703420443; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=ASUrErE9IB4rBsV06LSlQI5+Mv2WPJpJ2KbkeexjDLU=; b=gU29NcpZF16mxO3rhk+Vpw/IQjjl3LlDIgKLDODM66RmYBDd46BTaWsCCjgqxbkVD4 MWKo4VdJFnNJskKO3OhI/EdBaihK8R59fn+q72bXEgs7PMm1DuYSTTgrGIh7X+22bYrc fMibr4USVqz3mOOy1u5NNu7p+T6mlg0cQdIlqfIm/WMckAFoddtRvcTwMdK9xzKFJgf4 l4sLvEfR7FKnJ2+O0TvMGQdLf9U4naOXr0gaIu3kvSGnwU7Nt1H6viBNSmBaXVHmg64C TghNjzvHWPPGErgBxV/MYQs8wTa116fOORXBeML46EYXLx9YomXro3S/QMkbMqazhLEC MztA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1702815643; x=1703420443; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=ASUrErE9IB4rBsV06LSlQI5+Mv2WPJpJ2KbkeexjDLU=; b=FdN1Rf42iqi6YiJlO1sagajx0O5cHT6R52/LPno6wvB/uSiHOSG9vcKxA6HtfwO2zK P68wyR8rpWj7N57htOTkqe/oTUXyBiXvJos4E6lpR7uqlsv7y2ee1t6XCQ6mNEIcDjav nD2MpPppa1cD825FQ5Yg4aLTZD5cxMo/WkeARUMSvD5xrB8wDdsHT5VH5oj4gEM25/PK 86oMHo3akISjKPmJEPbtCH8OTW9FU8pleoQfhfsWmGDJox52nVL8BijbC0f3IaDzj86V Hwmh3B+xYkNsOZVmVq2+qiBCPhHc24Y9xzG2YsRTHTfOlhCcQ8fjNkj4dbhVW07Mg9e9 I0jw== X-Gm-Message-State: AOJu0Ywe/UYomVRdE+SO9x4RREd3pkl2l2vg3qYUMBgyZwDlpBMob/SX us6WYOqvPwFHtY4VKUF56ACppufz1Bqc1w== X-Received: by 2002:a2e:9c94:0:b0:2cc:5368:6c52 with SMTP id x20-20020a2e9c94000000b002cc53686c52mr1367636lji.93.1702815643222; Sun, 17 Dec 2023 04:20:43 -0800 (PST) Received: from localhost.localdomain (2a02-8388-0502-f480-6c32-186a-368b-d6a9.cable.dynamic.v6.surfer.at. [2a02:8388:502:f480:6c32:186a:368b:d6a9]) by smtp.gmail.com with ESMTPSA id es21-20020a056402381500b0055267663784sm3495621edb.11.2023.12.17.04.20.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 17 Dec 2023 04:20:42 -0800 (PST) From: Christoph Winklhofer To: krzysztof.kozlowski@linaro.org, robh+dt@kernel.org, conor+dt@kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Christoph Winklhofer Subject: [PATCH 1/2] dt-bindings: w1: UART 1-wire bus Date: Sun, 17 Dec 2023 13:20:03 +0100 Message-ID: <20231217122004.42795-2-cj.winklhofer@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20231217122004.42795-1-cj.winklhofer@gmail.com> References: <20231217122004.42795-1-cj.winklhofer@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1785531667774792718 X-GMAIL-MSGID: 1785531667774792718 Add device tree binding for UART 1-wire bus driver. Signed-off-by: Christoph Winklhofer --- .../devicetree/bindings/w1/w1-uart.yaml | 27 +++++++++++++++++++ 1 file changed, 27 insertions(+) create mode 100644 Documentation/devicetree/bindings/w1/w1-uart.yaml diff --git a/Documentation/devicetree/bindings/w1/w1-uart.yaml b/Documentation/devicetree/bindings/w1/w1-uart.yaml new file mode 100644 index 000000000000..1a4fbe1d7c60 --- /dev/null +++ b/Documentation/devicetree/bindings/w1/w1-uart.yaml @@ -0,0 +1,27 @@ +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/w1/w1-uart.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: UART 1-Wire Bus + +maintainers: + - Christoph Winklhofer + +properties: + compatible: + const: w1-uart + +required: + - compatible + +additionalProperties: false + +examples: + - | + serial { + onewire { + compatible = "w1-uart"; + }; + }; From patchwork Sun Dec 17 12:20:04 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Winklhofer X-Patchwork-Id: 180003 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a05:7300:24d3:b0:fb:cd0c:d3e with SMTP id r19csp675638dyi; Sun, 17 Dec 2023 04:21:38 -0800 (PST) X-Google-Smtp-Source: AGHT+IH/5Oe53s+MDJHhEQLw4NHS+PGOtdePXNkpUEvvjf6ovjTxHoZ5oQiFSq1GSZpT57pIvBVF X-Received: by 2002:a50:9fa8:0:b0:553:184a:a49 with SMTP id c37-20020a509fa8000000b00553184a0a49mr654201edf.151.1702815698121; Sun, 17 Dec 2023 04:21:38 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1702815698; cv=none; d=google.com; s=arc-20160816; b=OZUSdYKuw7pYcLBV1dDQa+R+oXm62T+qWQWau7MF9lOcafnY7mpfV6njguiTQ81l+o Up8nXijFp/wLa0goZYXWfpPyFWT7x54zvyoJ7OMUMjzUFSg3BfhuHNttrccdrrapq02A k42PjkVJce7DKSKHjcIlowsf50BuL0AzNHChecHhnlmTWL9EUbgpUJvNffkkoR/z4JJk ld9Gyp3Paz04s59OCialtwYL1tu3QkRk6B4428LFhfyMhCt/ZGgyzLdwwb1TaHPPHEmG MMF/N+dA1JVorVoH2tYZHNhNmYXKMeLkbml8Nmam+oa3FML9p/zARdYHeEyYxjI71C4d VLwg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-transfer-encoding:mime-version:list-unsubscribe :list-subscribe:list-id:precedence:references:in-reply-to:message-id :date:subject:cc:to:from:dkim-signature; bh=SV4tUKQSEvk0f5P2I2zO6ntBly6ayKPyNhOH2Mn+g8s=; fh=EI065BL1O5Z7XQnp588pIE3j/TBmNqn9jjQVJsWdQuk=; b=O7qBEEkfLnxZT44LSBcyx9cG0SVIWarkWaD64f5KZU8doJNqIOIsO8+G9VoRp98dn9 9BM+U5/825ePMIlSREEM2pEFybyaQJCM+2ImMqySUM+8N+UwtX52ZqHAAFK4DF/wjQBv UoHq6hQmBzX5tRplXlSWF1i/BqgHLosgEOOAwMIDy59kyVniAYTiNIMPx062N2Jn7cgK WFXAXkuR7+zXq2MpZ3pyOA9S6iDa5J/I0E8fkKWRnMfTQA8ZhruRqRhEMnjM/OXd1LDt kgV3H/7ORWda5RAcUTm413ai83izVj4f91bL7mrTw/jXT7zxcqeRDzDqHnBnxMSosD44 oy7Q== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20230601 header.b=jg57VAxc; spf=pass (google.com: domain of linux-kernel+bounces-2572-ouuuleilei=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) smtp.mailfrom="linux-kernel+bounces-2572-ouuuleilei=gmail.com@vger.kernel.org"; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: from am.mirrors.kernel.org (am.mirrors.kernel.org. [2604:1380:4601:e00::3]) by mx.google.com with ESMTPS id i18-20020a508712000000b0054d88a05cddsi9330034edb.611.2023.12.17.04.21.37 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 17 Dec 2023 04:21:38 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel+bounces-2572-ouuuleilei=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) client-ip=2604:1380:4601:e00::3; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20230601 header.b=jg57VAxc; spf=pass (google.com: domain of linux-kernel+bounces-2572-ouuuleilei=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) smtp.mailfrom="linux-kernel+bounces-2572-ouuuleilei=gmail.com@vger.kernel.org"; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: from smtp.subspace.kernel.org (wormhole.subspace.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by am.mirrors.kernel.org (Postfix) with ESMTPS id 7DFA41F21443 for ; Sun, 17 Dec 2023 12:21:37 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id EB087364CE; Sun, 17 Dec 2023 12:20:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="jg57VAxc" X-Original-To: linux-kernel@vger.kernel.org Received: from mail-ed1-f51.google.com (mail-ed1-f51.google.com [209.85.208.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6F60932C84; Sun, 17 Dec 2023 12:20:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Received: by mail-ed1-f51.google.com with SMTP id 4fb4d7f45d1cf-5522ba3f94aso2302702a12.1; Sun, 17 Dec 2023 04:20:46 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1702815644; x=1703420444; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=SV4tUKQSEvk0f5P2I2zO6ntBly6ayKPyNhOH2Mn+g8s=; b=jg57VAxcgbF2rOowVFsQPmOxP8G5F26W5wUOSvfti/iYYJwNLTtHMxOHffFNCeeuSo 31hJ9Lcb49HEFph8uUlGcN8jVL1PGWKbBc7T182kb85ZTDzS4RUzISBF1fn3z4yx2Qaf 3KMahk3WgTQ2jP25RAr8RdOwFgEopWCWVN++juZkpQ/6sdhmJIL0pK8CgNCxTW8Fp0KA 3eusVteWc9lynM2Hh+qLMXdKEEPcN3Ypp47JtXbR9sX1gIEBOySWcH2OnqgNX/YdUbBf RcMNwpnyY6Tam7HiFCmX6edRtd7mui7emK9zVE3tYfFmKK9FUs37GtlpnKO9oAnD3uJw t+1Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1702815644; x=1703420444; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=SV4tUKQSEvk0f5P2I2zO6ntBly6ayKPyNhOH2Mn+g8s=; b=EQkpYHN+J02iD8oSaTkSUKSbrHHK6sawXBaBsyf60d6YHbVEIz2ohoqh5wkZJzPrYc qyFQxWR29rGtI2cs5NYtra4PuvfazhwE+Gi6RL/lze9LsOkHosCucsd+lbZ5Y2aVsgrM C4w1NstkaZxczPcAWCEccxbVe/xARMPFZslSHvWZBegFpEHII6Yi0XekN2diY1y5Tkue SAkGHlfawjxywqaSyquKp7vIck3o5wzDbsjHgZY1yG7DGwt8/o3piRgAsEkg63F8vJfR CiY4e7jYfNb6fsidERpp+DQc6P7Eo2CKuPtDE/M+tK1WBj1V6mPYpPRCVWnSLrp4nFUO d+1Q== X-Gm-Message-State: AOJu0YyY8qbVh8HyTkqRfCxeNVYvjVw3rubSFGby4cmuC6hjZSDE05Lo z6NldfntxXBNa5XNQ7RWN3QDDq320JLwMA== X-Received: by 2002:a50:c251:0:b0:552:918f:1346 with SMTP id t17-20020a50c251000000b00552918f1346mr1524393edf.80.1702815644428; Sun, 17 Dec 2023 04:20:44 -0800 (PST) Received: from localhost.localdomain (2a02-8388-0502-f480-6c32-186a-368b-d6a9.cable.dynamic.v6.surfer.at. [2a02:8388:502:f480:6c32:186a:368b:d6a9]) by smtp.gmail.com with ESMTPSA id es21-20020a056402381500b0055267663784sm3495621edb.11.2023.12.17.04.20.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 17 Dec 2023 04:20:44 -0800 (PST) From: Christoph Winklhofer To: krzysztof.kozlowski@linaro.org, robh+dt@kernel.org, conor+dt@kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Christoph Winklhofer Subject: [PATCH 2/2] w1: add UART w1 bus driver Date: Sun, 17 Dec 2023 13:20:04 +0100 Message-ID: <20231217122004.42795-3-cj.winklhofer@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20231217122004.42795-1-cj.winklhofer@gmail.com> References: <20231217122004.42795-1-cj.winklhofer@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1785531643399139168 X-GMAIL-MSGID: 1785531673534677240 Add a UART 1-wire bus driver. The driver utilizes the UART interface via the Serial Device Bus to create the 1-wire timing patterns. The driver was tested on a "Raspberry Pi 3B" with a DS18B20 and on a "Variscite DART-6UL" with a DS18S20 temperature sensor. The 1-wire timing pattern and the corresponding UART baud-rate with the interpretation of the transferred bytes are described in the document: Link: https://www.analog.com/en/technical-articles/using-a-uart-to-implement-a-1wire-bus-master.html In short, the UART peripheral must support full-duplex and operate in open-drain mode. The timing patterns are generated by a specific combination of baud-rate and transmitted byte, which corresponds to a 1-Wire read bit, write bit or reset. Signed-off-by: Christoph Winklhofer --- Documentation/w1/masters/index.rst | 1 + Documentation/w1/masters/w1-uart.rst | 48 +++++++ drivers/w1/masters/Kconfig | 10 ++ drivers/w1/masters/Makefile | 1 + drivers/w1/masters/w1-uart.c | 189 +++++++++++++++++++++++++++ 5 files changed, 249 insertions(+) create mode 100644 Documentation/w1/masters/w1-uart.rst create mode 100644 drivers/w1/masters/w1-uart.c diff --git a/Documentation/w1/masters/index.rst b/Documentation/w1/masters/index.rst index 4442a98850ad..cc40189909fd 100644 --- a/Documentation/w1/masters/index.rst +++ b/Documentation/w1/masters/index.rst @@ -12,3 +12,4 @@ mxc-w1 omap-hdq w1-gpio + w1-uart diff --git a/Documentation/w1/masters/w1-uart.rst b/Documentation/w1/masters/w1-uart.rst new file mode 100644 index 000000000000..0f546cf77f13 --- /dev/null +++ b/Documentation/w1/masters/w1-uart.rst @@ -0,0 +1,48 @@ +.. SPDX-License-Identifier: GPL-2.0-or-later + +===================== +Kernel driver w1-uart +===================== + +Author: Christoph Winklhofer + + +Description +----------- + +UART 1-wire bus driver. The driver utilizes the UART interface via the +Serial Device Bus to create the 1-Wire timing patterns as described in +the document `"Using a UART to Implement a 1-Wire Bus Master"`_. + +.. _"Using a UART to Implement a 1-Wire Bus Master": https://www.analog.com/en/technical-articles/using-a-uart-to-implement-a-1wire-bus-master.html + +In short, the UART peripheral must support full-duplex and operate in +open-drain mode. The timing patterns are generated by a specific +combination of baud-rate and transmitted byte, which corresponds to a +1-Wire read bit, write bit or reset pulse. + +For instance the timing pattern for a 1-Wire reset and presence detect uses +the baud-rate 9600, i.e. 104.2 us per bit. The transmitted byte 0xf0 over +UART (least significant bit first, start-bit low) sets the reset low time +for 1-Wire to 521 us. A present 1-Wire device changes the received byte by +pulling the line low, which is used by the driver to evaluate the result of +the 1-Wire operation. + +Similar for a 1-Wire read bit or write bit, which uses the baud-rate +115200, i.e. 8.7 us per bit. The transmitted byte 0x00 is used for a +Write-0 operation and the byte 0xff for Read-0, Read-1 and Write-1. + + +Usage +----- + +Specify the UART 1-wire bus in the device tree by adding the single child +onewire to the serial node (e.g. uart0). For example: +:: + + @uart0 { + ... + onewire { + compatible = "w1-uart"; + }; + }; diff --git a/drivers/w1/masters/Kconfig b/drivers/w1/masters/Kconfig index 513c0b114337..e6049a75b35b 100644 --- a/drivers/w1/masters/Kconfig +++ b/drivers/w1/masters/Kconfig @@ -78,5 +78,15 @@ config W1_MASTER_SGI This support is also available as a module. If so, the module will be called sgi_w1. +config W1_MASTER_UART + tristate "UART 1-wire driver" + depends on SERIAL_DEV_BUS + help + Say Y here if you want to communicate with your 1-wire devices using + UART interface. + + This support is also available as a module. If so, the module + will be called w1-uart. + endmenu diff --git a/drivers/w1/masters/Makefile b/drivers/w1/masters/Makefile index 6c5a21f9b88c..227f80987e69 100644 --- a/drivers/w1/masters/Makefile +++ b/drivers/w1/masters/Makefile @@ -12,3 +12,4 @@ obj-$(CONFIG_W1_MASTER_MXC) += mxc_w1.o obj-$(CONFIG_W1_MASTER_GPIO) += w1-gpio.o obj-$(CONFIG_HDQ_MASTER_OMAP) += omap_hdq.o obj-$(CONFIG_W1_MASTER_SGI) += sgi_w1.o +obj-$(CONFIG_W1_MASTER_UART) += w1-uart.o diff --git a/drivers/w1/masters/w1-uart.c b/drivers/w1/masters/w1-uart.c new file mode 100644 index 000000000000..e0da8ebfef58 --- /dev/null +++ b/drivers/w1/masters/w1-uart.c @@ -0,0 +1,189 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * w1-uart - UART 1-Wire bus driver + * + * Uses the UART interface (via Serial Device Bus) to create the 1-Wire + * timing patterns. Implements the following 1-Wire master interface: + * + * - reset_bus: baud-rate 9600 (bit time 104.2 us) and tx-byte 0xf0 + * + * - touch_bit: baud-rate 115200 (bit time 8.7 us) and tx-byte 0x00 + * (Write-0) or 0xff (Read-0, Read-1, Write-1) + * + * Author: Christoph Winklhofer + */ + +#include +#include +#include +#include +#include +#include +#include + +#define W1_UART_TIMEOUT msecs_to_jiffies(500) + +struct w1_uart_device { + struct serdev_device *serdev; + struct w1_bus_master bus; + + struct completion buf_received; + atomic_t buf; + + unsigned int baudrate; +}; + +/* + * Send one byte (tx_byte) and read one byte (rx_byte) via serdev. + */ +static int w1_uart_serdev_tx_rx(struct w1_uart_device *w1dev, + unsigned int baudrate, unsigned char tx_byte, + unsigned char *rx_byte) +{ + struct serdev_device *serdev = w1dev->serdev; + struct device *dev = &serdev->dev; + int ret; + + serdev_device_write_flush(serdev); + if (w1dev->baudrate != baudrate) { + w1dev->baudrate = serdev_device_set_baudrate(serdev, baudrate); + if (w1dev->baudrate != baudrate) { + dev_err(dev, "set baudrate failed\n"); + return -1; + } + } + + reinit_completion(&w1dev->buf_received); + ret = serdev_device_write_buf(serdev, &tx_byte, 1); + if (ret != 1) { + dev_err(dev, "write failed\n"); + return -1; + } + ret = wait_for_completion_interruptible_timeout(&w1dev->buf_received, + W1_UART_TIMEOUT); + if (ret <= 0) { + dev_err(dev, "receive failed\n"); + return -1; + } + + *rx_byte = (unsigned char)atomic_read(&w1dev->buf); + return 0; +} + +static int w1_uart_serdev_receive_buf(struct serdev_device *serdev, + const unsigned char *buf, size_t count) +{ + struct w1_uart_device *w1dev = serdev_device_get_drvdata(serdev); + + if (count > 0) { + atomic_set(&w1dev->buf, buf[count - 1]); + complete(&w1dev->buf_received); + } + + return count; +} + +static const struct serdev_device_ops w1_uart_serdev_ops = { + .receive_buf = w1_uart_serdev_receive_buf, + .write_wakeup = serdev_device_write_wakeup, +}; + +/* + * 1-wire reset and presence detect: + * The baud-rate 9600 (104.2 us per bit) and the byte 0xf0 generates a + * reset low time of 521 us (start-bit low). A present slave will + * manipulate the received byte by pulling the 1-wire low. + */ +static u8 w1_uart_reset_bus(void *data) +{ + struct w1_uart_device *w1dev = data; + unsigned char buf; + int ret; + + ret = w1_uart_serdev_tx_rx(w1dev, 9600, 0xf0, &buf); + if (ret < 0) + return -1; + + /* Device present (0) or no device (1) */ + return buf != 0xf0 ? 0 : 1; +} + +/* + * 1-Wire read and write cycle: + * The baud-rate 115200 (8.7 us per bit) and the byte 0xff generates the + * timing pattern for Read-0, Read-1 and Write-1 operation, with a low + * time of 8.7 us (start-bit low). Only the Read-0 manipulates the + * received byte, all others left the line untouched. + */ +static u8 w1_uart_touch_bit(void *data, u8 bit) +{ + struct w1_uart_device *w1dev = data; + unsigned char buf; + int ret; + + ret = w1_uart_serdev_tx_rx(w1dev, 115200, bit ? 0xff : 0x00, &buf); + /* return inactive bus state on error */ + if (ret < 0) + return 1; + + return buf == 0xff ? 1 : 0; +} + +static int w1_uart_probe(struct serdev_device *serdev) +{ + struct device *dev = &serdev->dev; + struct w1_uart_device *w1dev; + int ret; + + w1dev = devm_kzalloc(dev, sizeof(struct w1_uart_device), GFP_KERNEL); + if (!w1dev) + return -ENOMEM; + w1dev->bus.data = w1dev; + w1dev->bus.reset_bus = w1_uart_reset_bus; + w1dev->bus.touch_bit = w1_uart_touch_bit; + w1dev->serdev = serdev; + + serdev_device_set_drvdata(serdev, w1dev); + serdev_device_set_client_ops(serdev, &w1_uart_serdev_ops); + + init_completion(&w1dev->buf_received); + + ret = devm_serdev_device_open(dev, serdev); + if (ret < 0) + return ret; + serdev_device_set_parity(serdev, SERDEV_PARITY_NONE); + serdev_device_set_flow_control(serdev, false); + + return w1_add_master_device(&w1dev->bus); +} + +static void w1_uart_remove(struct serdev_device *serdev) +{ + struct w1_uart_device *w1dev = serdev_device_get_drvdata(serdev); + + complete(&w1dev->buf_received); + w1_remove_master_device(&w1dev->bus); +} + +#ifdef CONFIG_OF +static const struct of_device_id w1_uart_of_match[] = { + { .compatible = "w1-uart" }, + {}, +}; +MODULE_DEVICE_TABLE(of, w1_uart_of_match); +#endif + +static struct serdev_device_driver w1_uart_driver = { + .driver = { + .name = "w1-uart", + .of_match_table = of_match_ptr(w1_uart_of_match), + }, + .probe = w1_uart_probe, + .remove = w1_uart_remove, +}; + +module_serdev_device_driver(w1_uart_driver); + +MODULE_DESCRIPTION("UART w1 bus driver"); +MODULE_AUTHOR("Christoph Winklhofer "); +MODULE_LICENSE("GPL");