From patchwork Sun Dec 17 12:20:02 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Winklhofer X-Patchwork-Id: 755180 Received: from mail-ed1-f50.google.com (mail-ed1-f50.google.com [209.85.208.50]) (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 E7F14EADB; Sun, 17 Dec 2023 12:20:43 +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 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="M4CFEQ3k" Received: by mail-ed1-f50.google.com with SMTP id 4fb4d7f45d1cf-551c03ae050so2162096a12.2; Sun, 17 Dec 2023 04:20:43 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1702815642; x=1703420442; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=6xMyvQ0D0+nEZ9Gai87Uhvht57Iu3iXC8pPekH44If4=; b=M4CFEQ3kVnOPO0sqWQWu+rNURTI2SFCcyN4fKjpIGstSQemT0lZJQi0BBA5GLP8ti7 t9qVrWBhkAkjUzi6+pN16FzGqoJjM4i66rFPp54IxzP1uKWvl0z0WLxKKULdnceUCU4W K2+cmqx8ZnC5mqSOD1FtuMQaopgzgUh6FRBZ4TOsy4XbdqW19oeVCp6p38H+UekmfNia VmKF9uaBOAeJCRmdfm9lq5K7TZcd5pFbR8JbodO3/e7eE7pbQFmsktav/vWAGG+G/59R cZO+wQfdxgCCTxs4bBPb6b/JV3xozvO1+y4vN3T2QHmZIs+lNXFlRh/xNY+lHlJdrz5w zLCQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1702815642; x=1703420442; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=6xMyvQ0D0+nEZ9Gai87Uhvht57Iu3iXC8pPekH44If4=; b=I6HroWnXOYqZHNsq9KiwlseTd6j3tmNRiiZGBRTEcXktF+C3n8pTN7cmKV6K6X9R0s aU31Oe98FYZrgGjn3HBaPkwb3GZ8OQgnJATVkROmeK9U1gWfSZ0JD1yykMk3JniYzbqg aZjERxBsMuLg0hOMX8edvCCsopFsitwY9QhcvBnVeTL2U/U02rSjBe+jtZwQAQbh2n5B i1DvSNAfUKEvqk62+6gWSHSTRPl2ARu0+Egxa+vs6WBHxEE2C3Szu1qOYWcRvmDtUixK i+iuPbrBxEkYh4IZBzvxgWjUBUiY1KB9C8XZLA3ZHcGjKi6ImPwvIsalS/W6s184aevW 4YCA== X-Gm-Message-State: AOJu0YxC6dGm8Tknn0cfcv6iDLLRlDitiuBokKMfwBCxwC0AfYbW+3YH cx0ISaKLqKAq6MtwCZ+nKA2EKmxGm8EqYQ== X-Google-Smtp-Source: AGHT+IF8tBF81mVrLJRXLBc0CJHYJ8+mpwFKXqaSPEhBWtum8EU0q3MnMciWOn80wXXHftsNScwoUg== X-Received: by 2002:a50:ccd0:0:b0:54b:f6f7:9c4d with SMTP id b16-20020a50ccd0000000b0054bf6f79c4dmr7435314edj.38.1702815642009; Sun, 17 Dec 2023 04:20:42 -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.11.2023.12.17.04.20.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 17 Dec 2023 04:20:41 -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 0/2] w1: add UART w1 bus driver Date: Sun, 17 Dec 2023 13:20:02 +0100 Message-ID: <20231217122004.42795-1-cj.winklhofer@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Hello! This patch set contains a driver for a 1-Wire bus over UART. The driver utilizes the UART interface via the Serial Device Bus to create the 1-Wire timing patterns. It was tested on a "Raspberry Pi 3 Model B+" with a DS18B20 and on a "Variscite DART-6UL" with a DS18S20 temperature sensor. Content: - Patch 1: device tree binding - Patch 2: driver and documentation The patch was created against the w1 subsytem tree (branch w1-next): Link: https://git.kernel.org/pub/scm/linux/kernel/git/krzk/linux-w1.git/ The checkpatch.pl script reported the following error - which I am not sure how to fix: WARNING: added, moved or deleted file(s), does MAINTAINERS need updating? The technical details for 1-Wire over UART are 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 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. Hope the driver is helpful. Thanks, Christoph Christoph Winklhofer (2): dt-bindings: w1: UART 1-wire bus w1: add UART w1 bus driver .../devicetree/bindings/w1/w1-uart.yaml | 27 +++ 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 ++++++++++++++++++ 6 files changed, 276 insertions(+) create mode 100644 Documentation/devicetree/bindings/w1/w1-uart.yaml create mode 100644 Documentation/w1/masters/w1-uart.rst create mode 100644 drivers/w1/masters/w1-uart.c base-commit: efc19c44aa442197ddcbb157c6ca54a56eba8c4e