From patchwork Fri Jun 21 07:30:13 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wolfram Sang X-Patchwork-Id: 806932 Received: from mail.zeus03.de (zeus03.de [194.117.254.33]) (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 184DA16B743 for ; Fri, 21 Jun 2024 07:30:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=194.117.254.33 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718955036; cv=none; b=r23LDEdt+PssnlugBnkZmmo2ze5zEw/Wa+ufHFjdxyn6aDdiTkRfUp42H0y8xd8fWqRwAp6pXpZeNiTPPyTuE3vpwd1JLg7IEyI+6i1OZMwujVHn3bhtZDbjN10yg/17S+pCRj/Xaq86WN/U5729hjuBmba1mbYIAj8RdWaAqbw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718955036; c=relaxed/simple; bh=X8INLkskdkYTHO9nLO+bqJ3aacRr5rFB23PLTToBN9k=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=AYs8sWyp2jakxpVZdz2nWMjAI2GRuqNgotDJAM7sdzAMgLAtjhf8kzb1RrHliqMN/9Op2WpwUtIrj3JWLqqnzPkYYDLeRXlm3Umjop+JpPqjlOoYJZAXwj3Gttj+r83XAtlpyT+I0M/drmD1xq1Cv0E5jpvNm4wVAcafazIMWAY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sang-engineering.com; spf=pass smtp.mailfrom=sang-engineering.com; dkim=pass (2048-bit key) header.d=sang-engineering.com header.i=@sang-engineering.com header.b=ZxXVfpDa; arc=none smtp.client-ip=194.117.254.33 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sang-engineering.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sang-engineering.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=sang-engineering.com header.i=@sang-engineering.com header.b="ZxXVfpDa" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= sang-engineering.com; h=from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:content-transfer-encoding; s=k1; bh=DWqmJaYmk7gfwFyT7gufw56IyMYdyCsAGXbbSjiY3n0=; b=ZxXVfp Da1ik4V4mvkkHeHMjxdeMRcprHpBymgYHmxAAjWaGePsGR6z26V/SH8U9SMz3B63 rLYcn9+qsLZK8fnurJxK6FYSKx6WyAz7z9ztlAY0WSHPP/ATNBl125RKjnD8o4i7 kvJYKanq6GEWKxj9X90/cjCn69QYqiRAQd/cDKujxQMMVT+QwiyhveBM/u3x6nzE Z6gcSPWOa4d4aplRSRGPAf0GhC7EsCYuT6cXFN/W1gJeNdikaP9D+hpW2oVlXthF zttPYVnZvijhDwwZC6ZWn8im6PpmBAMPV/mhOzVOZyPLg6JwjIh/4+8ArgcNAnlQ ArMHLjLWw283xi3Q== Received: (qmail 1279191 invoked from network); 21 Jun 2024 09:30:32 +0200 Received: by mail.zeus03.de with ESMTPSA (TLS_AES_256_GCM_SHA384 encrypted, authenticated); 21 Jun 2024 09:30:32 +0200 X-UD-Smtp-Session: l3s3148p1@2mPHZ2EbFpAgAwDPXzjQABqqX1QYyOSW From: Wolfram Sang To: linux-kernel@vger.kernel.org Cc: Andi Shyti , Easwar Hariharan , Wolfram Sang , linux-i2c@vger.kernel.org Subject: [PATCH v4 6/6] docs: i2c: summary: be clearer with 'controller/target' and 'adapter/client' pairs Date: Fri, 21 Jun 2024 09:30:13 +0200 Message-ID: <20240621073015.5443-7-wsa+renesas@sang-engineering.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240621073015.5443-1-wsa+renesas@sang-engineering.com> References: <20240621073015.5443-1-wsa+renesas@sang-engineering.com> Precedence: bulk X-Mailing-List: linux-i2c@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 This not only includes rewording, but also where to put which emphasis on terms in this document. Signed-off-by: Wolfram Sang --- Documentation/i2c/summary.rst | 41 ++++++++++++++++++++--------------- 1 file changed, 24 insertions(+), 17 deletions(-) diff --git a/Documentation/i2c/summary.rst b/Documentation/i2c/summary.rst index ff8bda32b9c3..579a1c7df200 100644 --- a/Documentation/i2c/summary.rst +++ b/Documentation/i2c/summary.rst @@ -31,9 +31,7 @@ implement all the common SMBus protocol semantics or messages. Terminology =========== -The I2C bus connects one or more *controller* chips and one or more *target* -chips. - +The I2C bus connects one or more controller chips and one or more target chips. .. kernel-figure:: i2c_bus.svg :alt: Simple I2C bus with one controller and 3 targets @@ -41,28 +39,37 @@ chips. Simple I2C bus A **controller** chip is a node that starts communications with targets. In the -Linux kernel implementation it is called an **adapter** or bus. Adapter -drivers are in the ``drivers/i2c/busses/`` subdirectory. +Linux kernel implementation it is also called an "adapter" or "bus". Controller +drivers are usually in the ``drivers/i2c/busses/`` subdirectory. -An **algorithm** contains general code that can be used to implement a -whole class of I2C adapters. Each specific adapter driver either depends on -an algorithm driver in the ``drivers/i2c/algos/`` subdirectory, or includes -its own implementation. +An **algorithm** contains general code that can be used to implement a whole +class of I2C controllers. Each specific controller driver either depends on an +algorithm driver in the ``drivers/i2c/algos/`` subdirectory, or includes its +own implementation. A **target** chip is a node that responds to communications when addressed by a -controller. In the Linux kernel implementation it is called a **client**. While -targets are usually separate external chips, Linux can also act as a target -(needs hardware support) and respond to another controller on the bus. This is -then called a **local target**. In contrast, an external chip is called a -**remote target**. +controller. In the Linux kernel implementation it is also called a "client". +While targets are usually separate external chips, Linux can also act as a +target (needs hardware support) and respond to another controller on the bus. +This is then called a **local target**. In contrast, an external chip is called +a **remote target**. Target drivers are kept in a directory specific to the feature they provide, for example ``drivers/gpio/`` for GPIO expanders and ``drivers/media/i2c/`` for video-related chips. -For the example configuration in figure, you will need a driver for your -I2C adapter, and drivers for your I2C devices (usually one driver for each -device). +For the example configuration in the figure above, you will need one driver for +the I2C controller, and drivers for your I2C targets. Usually one driver for +each target. + +Synonyms +-------- + +As mentioned above, the Linux I2C implementation historically uses the terms +"adapter" for controller and "client" for target. A number of data structures +have these synonyms in their name. So, when discussing implementation details, +you should be aware of these terms as well. The official wording is preferred, +though. Outdated terminology --------------------