From patchwork Sat Jan 6 16:02:23 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Winklhofer via B4 Relay X-Patchwork-Id: 760475 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C17FB8475; Sat, 6 Jan 2024 16:02:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="PU8g1GHx" Received: by smtp.kernel.org (Postfix) with ESMTPS id 331B1C433C7; Sat, 6 Jan 2024 16:02:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1704556947; bh=CyU2HWnIK49IXRUVfIRsjtKjJMAK+3OujvoA9cvQ0X0=; h=From:Subject:Date:To:Cc:Reply-To:From; b=PU8g1GHxFTVl/Cns8oQEYxFY75s8den6NATRH6ym1Cp0giYTmjbhXelyV+5d+wr53 8AIPBtjXC5K38rVYekTEJwwJAwbd4i5qojM6C5Zz4tskqa22Z27hO91FLrZ5O+jrL2 QTGy0Pn0Y9TYBHFv47+pKKuy3ZUWdvFr1wgDRgrtHUMqfOtVsW0DFutGCblhUEdsj8 BEazUoNoLFvky7v8Cmlv28WzKfyKfk6o965ZHLdWdTjvwxMT0ftU0EGyjwHJanDd3I HvwlFtNUp59TSCb0xezTN56jNdmpQBdNO5jkGGuK1dAhyREW8nHXgCdEGBDwv6+cPr 6BdnR2Z0eSXKA== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id 11257C46CD2; Sat, 6 Jan 2024 16:02:27 +0000 (UTC) From: Christoph Winklhofer via B4 Relay Subject: [PATCH v4 0/3] w1: add UART w1 bus driver Date: Sat, 06 Jan 2024 17:02:23 +0100 Message-Id: <20240106-w1-uart-v4-0-7fe1378a8b3e@gmail.com> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-B4-Tracking: v=1; b=H4sIAI95mWUC/02OQQ6CMBBFr0K6dsiUtoCuvIdhUXGgVaCmIGgId 7eQYFzM4iXzX97MevKWenaKZuZptL11XQB5iFhpdFcT2FtglmAikaOEicNL+wGI8jRXmiutkIX vp6fKvjfTpQhcedfCYDzpfS94Eg5RYh5LiSoFDuU9nmz3aIyryJ/rVtsmLl27Co3tB+c/W9koV u0eoX4RowCE0JHhUVwTytI/RbEsyxcXaU7A3wAAAA== To: Krzysztof Kozlowski , Rob Herring , Conor Dooley , Christoph Winklhofer , Rob Herring , Greg Kroah-Hartman , Jiri Slaby , Krzysztof Kozlowski , Jonathan Corbet Cc: devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, linux-doc@vger.kernel.org X-Mailer: b4 0.12.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1704556945; l=5244; i=cj.winklhofer@gmail.com; s=20240104; h=from:subject:message-id; bh=CyU2HWnIK49IXRUVfIRsjtKjJMAK+3OujvoA9cvQ0X0=; b=No9PAQgILfnalERUJguZqJLrU+U8keYvsT4A5lqggEkxW0ywVnZ5uppBvbrzQt1rTqzQS8p/J JESQngfn4lDAjlA/GueYT0o4V9V4zbyU4ojZ0COZrtlhX6DEgMqf1yi X-Developer-Key: i=cj.winklhofer@gmail.com; a=ed25519; pk=lgjGjOt7hFKJT9UXhgUyrdthxvZ7DJ5F1U/7d9qdAsk= X-Endpoint-Received: by B4 Relay for cj.winklhofer@gmail.com/20240104 with auth_id=111 X-Original-From: Christoph Winklhofer Reply-To: Hello! This patch 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. Changes in v4: - rework baud-rate configuration: also check max bit-time, support higher baud-rates by adding a delay to complete 1-Wire cycle. - dt-binding w1-uart: specify baud-rates for 1-Wire operations - Link to v3: https://lore.kernel.org/r/20240105-w1-uart-v3-0-8687093b2e76@gmail.com Changes in v3: - improve baud-rate configuration: use specific limits for 1-Wire reset, touch-0 and touch-1 operation, compute in nanoseconds. - remove unused header atomic.h - use function instead of macro to compute bit-time from baud-rate - switch to b4 util to publish patch: missing recipients - Link to v2: https://lore.kernel.org/lkml/20231223100408.44056-1-cj.winklhofer@gmail.com Changes in v2: - add documentation for dt-binding - allow onewire as serial child node - support different baud-rates: The driver requests a baud-rate (9600 for reset and 115200 for write/read) and tries to adapt the transmitted byte according to the actual baud-rate returned from serdev. - fix locking problem for serdev-receive and w1-master reset/touch: The received byte is now protected with a mutex - instead of the atomic, which was used before due to the concurrent store and load. - explicit error in serdev-receive: Receiving more than one byte results in an error, since the w1-uart driver is the only writer, it writes a single-byte and should receive a single byte. - fix variable names, errno-returns, wrong define CONFIG_OF - fix log flooding - fix driver remove (error-path for rxtx-function) - Link to v1: https://lore.kernel.org/all/20231217122004.42795-1-cj.winklhofer@gmail.com Krzysztof, thank your very much for your feedback! 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 1-Wire - Patch 2: allow onewire as serial child node - Patch 3: 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 (3): dt-bindings: w1: UART 1-Wire bus dt-bindings: serial: allow onewire as child node w1: add UART w1 bus driver .../devicetree/bindings/serial/serial.yaml | 2 +- .../devicetree/bindings/w1/w1-uart.yaml | 44 +++ Documentation/w1/masters/index.rst | 1 + Documentation/w1/masters/w1-uart.rst | 53 +++ drivers/w1/masters/Kconfig | 10 + drivers/w1/masters/Makefile | 1 + drivers/w1/masters/w1-uart.c | 307 ++++++++++++++++++ 7 files changed, 417 insertions(+), 1 deletion(-) 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 --- 2.43.0 base-commit: efc19c44aa442197ddcbb157c6ca54a56eba8c4e --- Christoph Winklhofer (3): dt-bindings: w1: UART 1-Wire bus dt-bindings: serial: allow onewire as child node w1: add UART w1 bus driver .../devicetree/bindings/serial/serial.yaml | 2 +- Documentation/devicetree/bindings/w1/w1-uart.yaml | 62 ++++ Documentation/w1/masters/index.rst | 1 + Documentation/w1/masters/w1-uart.rst | 54 +++ drivers/w1/masters/Kconfig | 10 + drivers/w1/masters/Makefile | 1 + drivers/w1/masters/w1-uart.c | 398 +++++++++++++++++++++ 7 files changed, 527 insertions(+), 1 deletion(-) --- base-commit: efc19c44aa442197ddcbb157c6ca54a56eba8c4e change-id: 20240104-w1-uart-ee8685a15a50 Best regards,