From patchwork Mon Aug 8 14:17:00 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luca Ceresoli X-Patchwork-Id: 596292 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8D805C25B0C for ; Mon, 8 Aug 2022 14:17:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235330AbiHHORn (ORCPT ); Mon, 8 Aug 2022 10:17:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46342 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243322AbiHHORm (ORCPT ); Mon, 8 Aug 2022 10:17:42 -0400 Received: from relay2-d.mail.gandi.net (relay2-d.mail.gandi.net [IPv6:2001:4b98:dc4:8::222]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A01282A2; Mon, 8 Aug 2022 07:17:41 -0700 (PDT) Received: from booty.fritz.box (unknown [77.244.183.192]) (Authenticated sender: luca.ceresoli@bootlin.com) by mail.gandi.net (Postfix) with ESMTPA id 941E440012; Mon, 8 Aug 2022 14:17:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1659968260; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=kkRPJXzP0mY0E2xI3MgL2tePFS/x97TuGCmrpd8sMf8=; b=HKqjwnT0YuT2hKZfdiLSvcNKsORkzCgBYN0bpfpUfVL+ASMO7n1HmCEoQN9S38/BvV/Sav /FZx5rHIIq2/kNaYFxqjLl7rQQ/DACOsmeVXw+8IH7UaFALAe9SaCj2ZZz2Qlt4miXe9nO fFQrZzk4msnkbSd6HKecTA1viE/RaE29r2XRHqufeVg9IR2GzSFtB1F75gsTcxweDH0PGx h+ErO44vvlnF3AjHoIOVGiaL1ssOS0MUV21vbKSXHuzvelLd8F5kpNiQgYquN7xzdWwq2F yCVJ0ps4slCI8+YM68nQmWGZeeSNRxdeq1mK8I1RXmI17eaBBwTAqOHbSuLfxw== From: luca.ceresoli@bootlin.com To: linux-doc@vger.kernel.org, linux-i2c@vger.kernel.org Cc: Luca Ceresoli , Wolfram Sang , Peter Rosin , linux-kernel@vger.kernel.org Subject: [PATCH 1/9] docs: i2c: i2c-protocol: update introductory paragraph Date: Mon, 8 Aug 2022 16:17:00 +0200 Message-Id: <20220808141708.1021103-2-luca.ceresoli@bootlin.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220808141708.1021103-1-luca.ceresoli@bootlin.com> References: <20220808141708.1021103-1-luca.ceresoli@bootlin.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org From: Luca Ceresoli This sentence dates back to the pre-git era and it does not look very prefessional... As there is no clear definition of "finished", and given this page is already a pretty good overview, not to mention it is not the kernel responsibility to document the protocol in detail, let's update the text accordingly. Signed-off-by: Luca Ceresoli --- Documentation/i2c/i2c-protocol.rst | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/Documentation/i2c/i2c-protocol.rst b/Documentation/i2c/i2c-protocol.rst index b2092f8f815d..9ecf03f5de33 100644 --- a/Documentation/i2c/i2c-protocol.rst +++ b/Documentation/i2c/i2c-protocol.rst @@ -2,7 +2,8 @@ The I2C Protocol ================ -This document describes the I2C protocol. Or will, when it is finished :-) +This document is an overview of the basic I2C transactions and the kernel +APIs to perform them. Key to symbols ============== From patchwork Mon Aug 8 14:17:01 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luca Ceresoli X-Patchwork-Id: 596138 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 17189C25B0E for ; Mon, 8 Aug 2022 14:17:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243431AbiHHORp (ORCPT ); Mon, 8 Aug 2022 10:17:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46374 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243357AbiHHORn (ORCPT ); Mon, 8 Aug 2022 10:17:43 -0400 Received: from relay2-d.mail.gandi.net (relay2-d.mail.gandi.net [217.70.183.194]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7FF26CDA; Mon, 8 Aug 2022 07:17:42 -0700 (PDT) Received: from booty.fritz.box (unknown [77.244.183.192]) (Authenticated sender: luca.ceresoli@bootlin.com) by mail.gandi.net (Postfix) with ESMTPA id 7642C40020; Mon, 8 Aug 2022 14:17:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1659968261; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=+RpzD04feUpzsPHQPlUrUQU23dieVOTj7WEn2/g+uqY=; b=jBpJOIP3kqmtpqCNy7/AtcMdVx3svr2ajsPfb6zQEr15GteYOSbidiRVygAHhm3aeaBa83 BTj0VmpLev7cd2q0EkHi8sXa3dlrpJWKQnuYu/luBBAgZeHknCnBJEMaP5t6zRrMTux09Y BgDWtaWB3/hJH/1IoIHoN2OWJ95kvt+ROmCFTwnA+YCnip2Ghlv+mAWEOHWQawiaAKCU1r MWUGjNYFqr1/3AF6BjA7C3+9SUVjZ8r6rSj4IVPkGilEX85NmSl9n3lBptq8ZVGE4un8d6 D2nVyF9i+yShfN6qQ0llSFHwEOmcc6Zw6tT77Prp4VyRg+WT48q/KePDlHVnhA== From: luca.ceresoli@bootlin.com To: linux-doc@vger.kernel.org, linux-i2c@vger.kernel.org Cc: Luca Ceresoli , Wolfram Sang , Peter Rosin , linux-kernel@vger.kernel.org Subject: [PATCH 2/9] docs: i2c: i2c-protocol,smbus-protocol: remove nonsense words Date: Mon, 8 Aug 2022 16:17:01 +0200 Message-Id: <20220808141708.1021103-3-luca.ceresoli@bootlin.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220808141708.1021103-1-luca.ceresoli@bootlin.com> References: <20220808141708.1021103-1-luca.ceresoli@bootlin.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org From: Luca Ceresoli "as usual" does not mean much here, especially as these are introductory sections and 10-bit addressing hasn't been introduced yet. Signed-off-by: Luca Ceresoli --- Documentation/i2c/i2c-protocol.rst | 2 +- Documentation/i2c/smbus-protocol.rst | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/Documentation/i2c/i2c-protocol.rst b/Documentation/i2c/i2c-protocol.rst index 9ecf03f5de33..7ffada1f3335 100644 --- a/Documentation/i2c/i2c-protocol.rst +++ b/Documentation/i2c/i2c-protocol.rst @@ -13,7 +13,7 @@ S Start condition P Stop condition Rd/Wr (1 bit) Read/Write bit. Rd equals 1, Wr equals 0. A, NA (1 bit) Acknowledge (ACK) and Not Acknowledge (NACK) bit -Addr (7 bits) I2C 7 bit address. Note that this can be expanded as usual to +Addr (7 bits) I2C 7 bit address. Note that this can be expanded to get a 10 bit I2C address. Comm (8 bits) Command byte, a data byte which often selects a register on the device. diff --git a/Documentation/i2c/smbus-protocol.rst b/Documentation/i2c/smbus-protocol.rst index 00d8e17d0aca..55e209c7e520 100644 --- a/Documentation/i2c/smbus-protocol.rst +++ b/Documentation/i2c/smbus-protocol.rst @@ -41,7 +41,7 @@ Sr Repeated start condition, used to switch from write to P Stop condition Rd/Wr (1 bit) Read/Write bit. Rd equals 1, Wr equals 0. A, NA (1 bit) Acknowledge (ACK) and Not Acknowledge (NACK) bit -Addr (7 bits) I2C 7 bit address. Note that this can be expanded as usual to +Addr (7 bits) I2C 7 bit address. Note that this can be expanded to get a 10 bit I2C address. Comm (8 bits) Command byte, a data byte which often selects a register on the device. From patchwork Mon Aug 8 14:17:02 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luca Ceresoli X-Patchwork-Id: 596137 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D9B93C282E7 for ; Mon, 8 Aug 2022 14:17:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243434AbiHHORq (ORCPT ); Mon, 8 Aug 2022 10:17:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46394 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243378AbiHHORo (ORCPT ); Mon, 8 Aug 2022 10:17:44 -0400 Received: from relay2-d.mail.gandi.net (relay2-d.mail.gandi.net [IPv6:2001:4b98:dc4:8::222]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8D616DF9; Mon, 8 Aug 2022 07:17:43 -0700 (PDT) Received: from booty.fritz.box (unknown [77.244.183.192]) (Authenticated sender: luca.ceresoli@bootlin.com) by mail.gandi.net (Postfix) with ESMTPA id 4B14D40022; Mon, 8 Aug 2022 14:17:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1659968262; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=7LWos+3Nat6ZJ6Jrt0Y6a2rt6FhVH50B0A/I/sZ/L0c=; b=RhQx0/m5oUl4IpNjZ7hGUz3SOa2uzgysGRElbtxe8in6kRSOwq9/HXT+UsJAkH8lRc7VlZ S3PMz2BrKD7/EuWfAoFQWYwqJqHyo76gABPoXWixnpkw2VBriZL2vkyS+hi+Cqqv+Mpz2Q vjIYAmILYArwcQsKjwz/0a27K3WOSU2Qe/U7O88frOZF3IjE6OHeriyvz9uVfB1VTccBys p2rkEZY78I+9LgoqCrmsS6fNFNsBX5iOmkuofT/glp3yRTzVtWAfgV60YGHnJxSwkzBmWa tqm6oVkrgZqQ83ssNbyoFaabZLG3ddWoT2H1It3d1+W/HGdiohTTeOvgc3acRQ== From: luca.ceresoli@bootlin.com To: linux-doc@vger.kernel.org, linux-i2c@vger.kernel.org Cc: Luca Ceresoli , Wolfram Sang , Peter Rosin , linux-kernel@vger.kernel.org Subject: [PATCH 3/9] docs: i2c: i2c-protocol: remove unused legend items Date: Mon, 8 Aug 2022 16:17:02 +0200 Message-Id: <20220808141708.1021103-4-luca.ceresoli@bootlin.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220808141708.1021103-1-luca.ceresoli@bootlin.com> References: <20220808141708.1021103-1-luca.ceresoli@bootlin.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org From: Luca Ceresoli "Comm", "Count", "DataLow", "DataHigh" are not used in this section. Signed-off-by: Luca Ceresoli --- Documentation/i2c/i2c-protocol.rst | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/Documentation/i2c/i2c-protocol.rst b/Documentation/i2c/i2c-protocol.rst index 7ffada1f3335..df0febfe6410 100644 --- a/Documentation/i2c/i2c-protocol.rst +++ b/Documentation/i2c/i2c-protocol.rst @@ -15,11 +15,7 @@ Rd/Wr (1 bit) Read/Write bit. Rd equals 1, Wr equals 0. A, NA (1 bit) Acknowledge (ACK) and Not Acknowledge (NACK) bit Addr (7 bits) I2C 7 bit address. Note that this can be expanded to get a 10 bit I2C address. -Comm (8 bits) Command byte, a data byte which often selects a register on - the device. -Data (8 bits) A plain data byte. Sometimes, I write DataLow, DataHigh - for 16 bit data. -Count (8 bits) A data byte containing the length of a block operation. +Data (8 bits) A plain data byte. [..] Data sent by I2C device, as opposed to data sent by the host adapter. From patchwork Mon Aug 8 14:17:03 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luca Ceresoli X-Patchwork-Id: 596291 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E80DDC25B08 for ; Mon, 8 Aug 2022 14:17:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243494AbiHHORy (ORCPT ); Mon, 8 Aug 2022 10:17:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46430 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243381AbiHHORp (ORCPT ); Mon, 8 Aug 2022 10:17:45 -0400 Received: from relay2-d.mail.gandi.net (relay2-d.mail.gandi.net [IPv6:2001:4b98:dc4:8::222]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6D1E3E1D; Mon, 8 Aug 2022 07:17:44 -0700 (PDT) Received: from booty.fritz.box (unknown [77.244.183.192]) (Authenticated sender: luca.ceresoli@bootlin.com) by mail.gandi.net (Postfix) with ESMTPA id 295DE40009; Mon, 8 Aug 2022 14:17:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1659968262; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=s8gzQTvX0pOI7ot4Zo9ZL6U8ilRBCDjzvp41cYqckpw=; b=Mz+jQQpjIJkcHGrl2iLMnHSCBUxWyXVhiK38JuREwBqHPK62+NNxawqtzcNxu4VzZmZOqa p+vFb//6xmRjCZjxGXsj5kuw9bGuxfJ+ubkNLjguNMSHtHWPqn5KH3gJ2Rro/9Il4DnKJW Rf34IkosI+BvDD1RoRXLkBJq6IaiMzm5rsQrAIaV1wLNRPtfNOFenmi7Eg4ZZCp4GSsn8p EWVa3yHtWlTqGRNs06QaKfnmTZY0+/q1uUZ3mWm4vJVju4GnlkP/GZaNvXoN12ZVVO6yhF DilbHSwOvijScvB1fdcrUayQHRdCoz0CNFmOeJbXKqG+zwYEk7ooaJmZ5P9CVg== From: luca.ceresoli@bootlin.com To: linux-doc@vger.kernel.org, linux-i2c@vger.kernel.org Cc: Luca Ceresoli , Wolfram Sang , Peter Rosin , linux-kernel@vger.kernel.org Subject: [PATCH 4/9] docs: i2c: smbus-protocol: improve DataLow/DataHigh definition Date: Mon, 8 Aug 2022 16:17:03 +0200 Message-Id: <20220808141708.1021103-5-luca.ceresoli@bootlin.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220808141708.1021103-1-luca.ceresoli@bootlin.com> References: <20220808141708.1021103-1-luca.ceresoli@bootlin.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org From: Luca Ceresoli Use a more professional wording. Signed-off-by: Luca Ceresoli --- Documentation/i2c/smbus-protocol.rst | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/Documentation/i2c/smbus-protocol.rst b/Documentation/i2c/smbus-protocol.rst index 55e209c7e520..4942c4cad4ad 100644 --- a/Documentation/i2c/smbus-protocol.rst +++ b/Documentation/i2c/smbus-protocol.rst @@ -45,8 +45,8 @@ Addr (7 bits) I2C 7 bit address. Note that this can be expanded to get a 10 bit I2C address. Comm (8 bits) Command byte, a data byte which often selects a register on the device. -Data (8 bits) A plain data byte. Sometimes, I write DataLow, DataHigh - for 16 bit data. +Data (8 bits) A plain data byte. DataLow and DataHigh represent the low and + high byte of a 16 bit word. Count (8 bits) A data byte containing the length of a block operation. [..] Data sent by I2C device, as opposed to data sent by the host From patchwork Mon Aug 8 14:17:04 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luca Ceresoli X-Patchwork-Id: 596136 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7F3CCC3F6B0 for ; Mon, 8 Aug 2022 14:17:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243282AbiHHORz (ORCPT ); Mon, 8 Aug 2022 10:17:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46444 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243443AbiHHORq (ORCPT ); Mon, 8 Aug 2022 10:17:46 -0400 Received: from relay2-d.mail.gandi.net (relay2-d.mail.gandi.net [217.70.183.194]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4CA55D53; Mon, 8 Aug 2022 07:17:45 -0700 (PDT) Received: from booty.fritz.box (unknown [77.244.183.192]) (Authenticated sender: luca.ceresoli@bootlin.com) by mail.gandi.net (Postfix) with ESMTPA id 23F4E40024; Mon, 8 Aug 2022 14:17:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1659968263; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=BBYpbjiOzI/XSRD48IW6eqP+HMklhyXTPxaqJfq58wo=; b=kgTWo0N5Sd0xVauvHQmzKFDU8l0lTVplBoDkMYUqXQ1HBm21S/btifYfOGEeR3TulgccR4 vYA1pX/fuDz4HlmrlXRtfHEUAjFf9DlNPoFvTZtn315zjHYDMG8Y1vwg70Iuc3ZSBfH542 T2QVes6oPM8U8vAJpEHyHXrShA+gIC17vdOlhb3YV+LLhWmoZDBf+LxiW51hjBiDdhmFgX 7bpJYMtVZPYTN4lZ5waK1xUgIueBnvKq/eF8rFG2rlQzh3QHpBXvDyQ2XPjzIgJAyoxeVO aLHV+Acse106gNtNSkCCkQmKKi6UEnoFmKYKYapCsa/AdCr9UVMs0kH76PB6zA== From: luca.ceresoli@bootlin.com To: linux-doc@vger.kernel.org, linux-i2c@vger.kernel.org Cc: Luca Ceresoli , Wolfram Sang , Peter Rosin , linux-kernel@vger.kernel.org Subject: [PATCH 5/9] docs: i2c: instantiating-devices: add syntax coloring to dts and C blocks Date: Mon, 8 Aug 2022 16:17:04 +0200 Message-Id: <20220808141708.1021103-6-luca.ceresoli@bootlin.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220808141708.1021103-1-luca.ceresoli@bootlin.com> References: <20220808141708.1021103-1-luca.ceresoli@bootlin.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org From: Luca Ceresoli These blocks can be nicely coloured via Sphinx. Signed-off-by: Luca Ceresoli --- Documentation/i2c/instantiating-devices.rst | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/Documentation/i2c/instantiating-devices.rst b/Documentation/i2c/instantiating-devices.rst index 890c9360ce19..3ea056a95812 100644 --- a/Documentation/i2c/instantiating-devices.rst +++ b/Documentation/i2c/instantiating-devices.rst @@ -31,7 +31,9 @@ Declare the I2C devices via devicetree On platforms using devicetree, the declaration of I2C devices is done in subnodes of the master controller. -Example:: +Example: + +.. code-block:: dts i2c1: i2c@400a0000 { /* ... master properties skipped ... */ @@ -71,7 +73,9 @@ code. Instantiating I2C devices via board files is done with an array of struct i2c_board_info which is registered by calling i2c_register_board_info(). -Example (from omap2 h4):: +Example (from omap2 h4): + +.. code-block:: c static struct i2c_board_info h4_i2c_board_info[] __initdata = { { @@ -111,7 +115,9 @@ bus in advance, so the method 1 described above can't be used. Instead, you can instantiate your I2C devices explicitly. This is done by filling a struct i2c_board_info and calling i2c_new_client_device(). -Example (from the sfe4001 network driver):: +Example (from the sfe4001 network driver): + +.. code-block:: c static struct i2c_board_info sfe4001_hwmon_info = { I2C_BOARD_INFO("max6647", 0x4e), @@ -136,7 +142,9 @@ it may have different addresses from one board to the next (manufacturer changing its design without notice). In this case, you can call i2c_new_scanned_device() instead of i2c_new_client_device(). -Example (from the nxp OHCI driver):: +Example (from the nxp OHCI driver): + +.. code-block:: c static const unsigned short normal_i2c[] = { 0x2c, 0x2d, I2C_CLIENT_END }; From patchwork Mon Aug 8 14:17:05 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luca Ceresoli X-Patchwork-Id: 596290 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 98C7BC25B0E for ; Mon, 8 Aug 2022 14:17:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243521AbiHHOR4 (ORCPT ); Mon, 8 Aug 2022 10:17:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46500 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243451AbiHHORr (ORCPT ); Mon, 8 Aug 2022 10:17:47 -0400 Received: from relay2-d.mail.gandi.net (relay2-d.mail.gandi.net [IPv6:2001:4b98:dc4:8::222]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 273DDE1F; Mon, 8 Aug 2022 07:17:46 -0700 (PDT) Received: from booty.fritz.box (unknown [77.244.183.192]) (Authenticated sender: luca.ceresoli@bootlin.com) by mail.gandi.net (Postfix) with ESMTPA id 239F740023; Mon, 8 Aug 2022 14:17:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1659968264; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=f/RQOfRAEuYlxpaBgdy2xoxxpuzSBGjIuj6Pa8upvDM=; b=Ffxeb1YNIarNews4CIJI8cbgm+UCqX/TGrmYlyB/rCOk1uWvq55WRCeN3a0RuY2dPp6M62 SHKNDJ2+dfVWf18dIIYC02PZ+G1I7HJZ6nCctaPGvJ3t6C9xsc58g/D+uQuwflqMRi5ZCv 7b6AIaMG9Wpjw8JvqB+YAX/yxlAtw37fHzvAdNUEYSEeC3s+5ujZTCorvsxtsxUYON8YYT 3jLXduWrSzCR8R3O+d5P8h0pR/e0FUgjN2cl2Nn0pTnq8GUchOSCD3AkL06DWq83yOaQ3A 3c8xQiEfaSDSg0qj2nQAE2dEqZaJvW2GSY6lq+w/kWFisf0xj9lUVeFsfrvUtg== From: luca.ceresoli@bootlin.com To: linux-doc@vger.kernel.org, linux-i2c@vger.kernel.org Cc: Luca Ceresoli , Wolfram Sang , Peter Rosin , linux-kernel@vger.kernel.org Subject: [PATCH 6/9] docs: i2c: i2c-topology: fix incorrect heading Date: Mon, 8 Aug 2022 16:17:05 +0200 Message-Id: <20220808141708.1021103-7-luca.ceresoli@bootlin.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220808141708.1021103-1-luca.ceresoli@bootlin.com> References: <20220808141708.1021103-1-luca.ceresoli@bootlin.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org From: Luca Ceresoli "Etc" here was never meant to be a heading, it became one while converting to ReST. It would be easy to just convert it to plain text, but rather remove it and add an introductory text before the list that conveys the same meaning but with a better reading flow. Fixes: ccf988b66d69 ("docs: i2c: convert to ReST and add to driver-api bookset") Signed-off-by: Luca Ceresoli --- Documentation/i2c/i2c-topology.rst | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/Documentation/i2c/i2c-topology.rst b/Documentation/i2c/i2c-topology.rst index 7cb53819778e..1b11535c8946 100644 --- a/Documentation/i2c/i2c-topology.rst +++ b/Documentation/i2c/i2c-topology.rst @@ -5,6 +5,8 @@ I2C muxes and complex topologies There are a couple of reasons for building more complex I2C topologies than a straight-forward I2C bus with one adapter and one or more devices. +Some example use cases are: + 1. A mux may be needed on the bus to prevent address collisions. 2. The bus may be accessible from some external bus master, and arbitration @@ -14,9 +16,6 @@ than a straight-forward I2C bus with one adapter and one or more devices. from the I2C bus, at least most of the time, and sits behind a gate that has to be operated before the device can be accessed. -Etc -=== - These constructs are represented as I2C adapter trees by Linux, where each adapter has a parent adapter (except the root adapter) and zero or more child adapters. The root adapter is the actual adapter that issues From patchwork Mon Aug 8 14:17:06 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luca Ceresoli X-Patchwork-Id: 596135 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1C927C25B08 for ; Mon, 8 Aug 2022 14:17:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243482AbiHHOR4 (ORCPT ); Mon, 8 Aug 2022 10:17:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46566 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231898AbiHHORt (ORCPT ); Mon, 8 Aug 2022 10:17:49 -0400 Received: from relay2-d.mail.gandi.net (relay2-d.mail.gandi.net [IPv6:2001:4b98:dc4:8::222]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 38047F2D; Mon, 8 Aug 2022 07:17:47 -0700 (PDT) Received: from booty.fritz.box (unknown [77.244.183.192]) (Authenticated sender: luca.ceresoli@bootlin.com) by mail.gandi.net (Postfix) with ESMTPA id F07CC4001D; Mon, 8 Aug 2022 14:17:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1659968265; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=gE5Me+n3eT2J+SCi3DhEyKj3QomarnaCcuG786z1UJY=; b=WugxYO1UCudpSAwWVAgC333QyRN5xz7NFOoSEkhS21hEaAShzSNQc7J76a21hSio7CW//6 7zfrEOcyIFAlJqP21cJXb8xgWwZ27VUmesT/JRXQWHLWkXlYlipvSA6bzrovP8CO3CPe1q eQj56hpN2GTPaAYgEzLwWQu5VpjvFba1+ADQ2tAC/1S/qWX08ZmMxRQhkrHVfCjFoUDI6o E4tLJ+n+Hh/7DMZvjT/GV5+n5s+6qivrU6pMRB29Bs4cZHbTdU8YhXFp8XWRZKk/FSTS2e ILgbTTI7vzEb5f8CER9QIJb5N0L40CwFLcpL4afiqCE4W4Yu8cMSwk1itLOFdw== From: luca.ceresoli@bootlin.com To: linux-doc@vger.kernel.org, linux-i2c@vger.kernel.org Cc: Luca Ceresoli , Wolfram Sang , Peter Rosin , linux-kernel@vger.kernel.org Subject: [PATCH 7/9] docs: i2c: i2c-topology: reorder sections more logically Date: Mon, 8 Aug 2022 16:17:06 +0200 Message-Id: <20220808141708.1021103-8-luca.ceresoli@bootlin.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220808141708.1021103-1-luca.ceresoli@bootlin.com> References: <20220808141708.1021103-1-luca.ceresoli@bootlin.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org From: Luca Ceresoli The sequence of sections is a bit confusing here: * we list the mux locking scheme for existing drivers before introducing what mux locking schemes are * we list the caveats for each locking scheme (which are tricky) before the example of the simple use case Restructure it entirely with the following logic: * Intro ("I2C muxes and complex topologies") * Locking - mux-locked - example - caveats - parent-locked - example - caveats * Complex examples * Mux type of existing device drivers While there, also apply some other improvements: * convert the caveat list from a table (with only one column carrying content) to a bullet list. * add a small introductory text to bridge the gap from listing the use cases to telling about the hardware components to handle them and then the device drivers that implement those. * make empty lines usage more uniform Signed-off-by: Luca Ceresoli --- Documentation/i2c/i2c-topology.rst | 206 +++++++++++++++-------------- 1 file changed, 109 insertions(+), 97 deletions(-) diff --git a/Documentation/i2c/i2c-topology.rst b/Documentation/i2c/i2c-topology.rst index 1b11535c8946..6f2da7f386fd 100644 --- a/Documentation/i2c/i2c-topology.rst +++ b/Documentation/i2c/i2c-topology.rst @@ -16,7 +16,10 @@ Some example use cases are: from the I2C bus, at least most of the time, and sits behind a gate that has to be operated before the device can be accessed. -These constructs are represented as I2C adapter trees by Linux, where +Several types of hardware components such as I2C muxes, I2C gates and I2C +arbitrators allow to handle such needs. + +These components are represented as I2C adapter trees by Linux, where each adapter has a parent adapter (except the root adapter) and zero or more child adapters. The root adapter is the actual adapter that issues I2C transfers, and all adapters with a parent are part of an "i2c-mux" @@ -34,46 +37,7 @@ Locking ======= There are two variants of locking available to I2C muxes, they can be -mux-locked or parent-locked muxes. As is evident from below, it can be -useful to know if a mux is mux-locked or if it is parent-locked. The -following list was correct at the time of writing: - -In drivers/i2c/muxes/: - -====================== ============================================= -i2c-arb-gpio-challenge Parent-locked -i2c-mux-gpio Normally parent-locked, mux-locked iff - all involved gpio pins are controlled by the - same I2C root adapter that they mux. -i2c-mux-gpmux Normally parent-locked, mux-locked iff - specified in device-tree. -i2c-mux-ltc4306 Mux-locked -i2c-mux-mlxcpld Parent-locked -i2c-mux-pca9541 Parent-locked -i2c-mux-pca954x Parent-locked -i2c-mux-pinctrl Normally parent-locked, mux-locked iff - all involved pinctrl devices are controlled - by the same I2C root adapter that they mux. -i2c-mux-reg Parent-locked -====================== ============================================= - -In drivers/iio/: - -====================== ============================================= -gyro/mpu3050 Mux-locked -imu/inv_mpu6050/ Mux-locked -====================== ============================================= - -In drivers/media/: - -======================= ============================================= -dvb-frontends/lgdt3306a Mux-locked -dvb-frontends/m88ds3103 Parent-locked -dvb-frontends/rtl2830 Parent-locked -dvb-frontends/rtl2832 Mux-locked -dvb-frontends/si2168 Mux-locked -usb/cx231xx/ Parent-locked -======================= ============================================= +mux-locked or parent-locked muxes. Mux-locked muxes @@ -88,40 +52,8 @@ full transaction, unrelated I2C transfers may interleave the different stages of the transaction. This has the benefit that the mux driver may be easier and cleaner to implement, but it has some caveats. -==== ===================================================================== -ML1. If you build a topology with a mux-locked mux being the parent - of a parent-locked mux, this might break the expectation from the - parent-locked mux that the root adapter is locked during the - transaction. - -ML2. It is not safe to build arbitrary topologies with two (or more) - mux-locked muxes that are not siblings, when there are address - collisions between the devices on the child adapters of these - non-sibling muxes. - - I.e. the select-transfer-deselect transaction targeting e.g. device - address 0x42 behind mux-one may be interleaved with a similar - operation targeting device address 0x42 behind mux-two. The - intension with such a topology would in this hypothetical example - be that mux-one and mux-two should not be selected simultaneously, - but mux-locked muxes do not guarantee that in all topologies. - -ML3. A mux-locked mux cannot be used by a driver for auto-closing - gates/muxes, i.e. something that closes automatically after a given - number (one, in most cases) of I2C transfers. Unrelated I2C transfers - may creep in and close prematurely. - -ML4. If any non-I2C operation in the mux driver changes the I2C mux state, - the driver has to lock the root adapter during that operation. - Otherwise garbage may appear on the bus as seen from devices - behind the mux, when an unrelated I2C transfer is in flight during - the non-I2C mux-changing operation. -==== ===================================================================== - - Mux-locked Example ------------------- - +~~~~~~~~~~~~~~~~~~ :: @@ -152,6 +84,39 @@ This means that accesses to D2 are lockout out for the full duration of the entire operation. But accesses to D3 are possibly interleaved at any point. +Mux-locked caveats +~~~~~~~~~~~~~~~~~~ + +When using a mux-locked mux, be aware of the following restrictions: + +* If you build a topology with a mux-locked mux being the parent + of a parent-locked mux, this might break the expectation from the + parent-locked mux that the root adapter is locked during the + transaction. + +* It is not safe to build arbitrary topologies with two (or more) + mux-locked muxes that are not siblings, when there are address + collisions between the devices on the child adapters of these + non-sibling muxes. + + I.e. the select-transfer-deselect transaction targeting e.g. device + address 0x42 behind mux-one may be interleaved with a similar + operation targeting device address 0x42 behind mux-two. The + intension with such a topology would in this hypothetical example + be that mux-one and mux-two should not be selected simultaneously, + but mux-locked muxes do not guarantee that in all topologies. + +* A mux-locked mux cannot be used by a driver for auto-closing + gates/muxes, i.e. something that closes automatically after a given + number (one, in most cases) of I2C transfers. Unrelated I2C transfers + may creep in and close prematurely. + +* If any non-I2C operation in the mux driver changes the I2C mux state, + the driver has to lock the root adapter during that operation. + Otherwise garbage may appear on the bus as seen from devices + behind the mux, when an unrelated I2C transfer is in flight during + the non-I2C mux-changing operation. + Parent-locked muxes ------------------- @@ -160,28 +125,10 @@ Parent-locked muxes lock the parent adapter during the full select- transfer-deselect transaction. The implication is that the mux driver has to ensure that any and all I2C transfers through that parent adapter during the transaction are unlocked I2C transfers (using e.g. -__i2c_transfer), or a deadlock will follow. There are a couple of -caveats. - -==== ==================================================================== -PL1. If you build a topology with a parent-locked mux being the child - of another mux, this might break a possible assumption from the - child mux that the root adapter is unused between its select op - and the actual transfer (e.g. if the child mux is auto-closing - and the parent mux issues I2C transfers as part of its select). - This is especially the case if the parent mux is mux-locked, but - it may also happen if the parent mux is parent-locked. - -PL2. If select/deselect calls out to other subsystems such as gpio, - pinctrl, regmap or iio, it is essential that any I2C transfers - caused by these subsystems are unlocked. This can be convoluted to - accomplish, maybe even impossible if an acceptably clean solution - is sought. -==== ==================================================================== - +__i2c_transfer), or a deadlock will follow. Parent-locked Example ---------------------- +~~~~~~~~~~~~~~~~~~~~~ :: @@ -211,10 +158,29 @@ When there is an access to D1, this happens: 9. M1 unlocks its parent adapter. 10. M1 unlocks muxes on its parent. - This means that accesses to both D2 and D3 are locked out for the full duration of the entire operation. +Parent-locked Caveats +~~~~~~~~~~~~~~~~~~~~~ + +When using a parent-locked mux, be aware of the following restrictions: + +* If you build a topology with a parent-locked mux being the child + of another mux, this might break a possible assumption from the + child mux that the root adapter is unused between its select op + and the actual transfer (e.g. if the child mux is auto-closing + and the parent mux issues I2C transfers as part of its select). + This is especially the case if the parent mux is mux-locked, but + it may also happen if the parent mux is parent-locked. + +* If select/deselect calls out to other subsystems such as gpio, + pinctrl, regmap or iio, it is essential that any I2C transfers + caused by these subsystems are unlocked. This can be convoluted to + accomplish, maybe even impossible if an acceptably clean solution + is sought. + + Complex Examples ================ @@ -260,8 +226,10 @@ This is a good topology:: When device D1 is accessed, accesses to D2 are locked out for the full duration of the operation (muxes on the top child adapter of M1 are locked). But accesses to D3 and D4 are possibly interleaved at -any point. Accesses to D3 locks out D1 and D2, but accesses to D4 -are still possibly interleaved. +any point. + +Accesses to D3 locks out D1 and D2, but accesses to D4 are still possibly +interleaved. Mux-locked mux as parent of parent-locked mux @@ -393,3 +361,47 @@ This is a good topology:: When D1 or D2 are accessed, accesses to D3 and D4 are locked out while accesses to D5 may interleave. When D3 or D4 are accessed, accesses to all other devices are locked out. + + +Mux type of existing device drivers +=================================== + +Whether a device is mux-locked or parent-locked depends on its +implementation. The following list was correct at the time of writing: + +In drivers/i2c/muxes/: + +====================== ============================================= +i2c-arb-gpio-challenge Parent-locked +i2c-mux-gpio Normally parent-locked, mux-locked iff + all involved gpio pins are controlled by the + same I2C root adapter that they mux. +i2c-mux-gpmux Normally parent-locked, mux-locked iff + specified in device-tree. +i2c-mux-ltc4306 Mux-locked +i2c-mux-mlxcpld Parent-locked +i2c-mux-pca9541 Parent-locked +i2c-mux-pca954x Parent-locked +i2c-mux-pinctrl Normally parent-locked, mux-locked iff + all involved pinctrl devices are controlled + by the same I2C root adapter that they mux. +i2c-mux-reg Parent-locked +====================== ============================================= + +In drivers/iio/: + +====================== ============================================= +gyro/mpu3050 Mux-locked +imu/inv_mpu6050/ Mux-locked +====================== ============================================= + +In drivers/media/: + +======================= ============================================= +dvb-frontends/lgdt3306a Mux-locked +dvb-frontends/m88ds3103 Parent-locked +dvb-frontends/rtl2830 Parent-locked +dvb-frontends/rtl2832 Mux-locked +dvb-frontends/si2168 Mux-locked +usb/cx231xx/ Parent-locked +======================= ============================================= From patchwork Mon Aug 8 14:17:07 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luca Ceresoli X-Patchwork-Id: 596289 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C6079C28B2C for ; Mon, 8 Aug 2022 14:17:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243534AbiHHOR5 (ORCPT ); Mon, 8 Aug 2022 10:17:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46760 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243477AbiHHORy (ORCPT ); Mon, 8 Aug 2022 10:17:54 -0400 Received: from relay2-d.mail.gandi.net (relay2-d.mail.gandi.net [IPv6:2001:4b98:dc4:8::222]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7977E2185; Mon, 8 Aug 2022 07:17:48 -0700 (PDT) Received: from booty.fritz.box (unknown [77.244.183.192]) (Authenticated sender: luca.ceresoli@bootlin.com) by mail.gandi.net (Postfix) with ESMTPA id D91B840021; Mon, 8 Aug 2022 14:17:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1659968266; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Vse0PXbfgREFWzjPw765Sr7JMn/or8fQexoNuL2Z1o0=; b=JvAV4ABjljWyPhGQmfuWo0DDdGgRa7hTwWhoRFvR8yOJ/F4s2ObP8kRPNGMdQNXlMs0XAn HxjqQXzBDPg0hUQvu73Rc6XnEl+bOZ62B5LrGVbnOXSkt+u72GojJd9un6W/f3D5nlSkVW XJRbYOoxl5FAEvlhucoTh7sQQAQmctzDTvzZsMo6aYoJ3oW9HoqYeaXlX8wToM7toTa2rH 6jaZWtBT1khCKHLqRGCNZv60HcPT7IFWLNuXFzSxhM0MuRb6CKZJnaW/UtLVFdlBuOC1BQ AHMasrELZKsw1Mi0XTBmjgbTNgozw+a78W+x3I55y0EVFOOSVjkcJCKmTPG5Eg== From: luca.ceresoli@bootlin.com To: linux-doc@vger.kernel.org, linux-i2c@vger.kernel.org Cc: Luca Ceresoli , Wolfram Sang , Peter Rosin , linux-kernel@vger.kernel.org Subject: [PATCH 8/9] docs: i2c: i2c-sysfs: improve wording Date: Mon, 8 Aug 2022 16:17:07 +0200 Message-Id: <20220808141708.1021103-9-luca.ceresoli@bootlin.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220808141708.1021103-1-luca.ceresoli@bootlin.com> References: <20220808141708.1021103-1-luca.ceresoli@bootlin.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org From: Luca Ceresoli Improve wording in a couple sentences. Signed-off-by: Luca Ceresoli --- Documentation/i2c/i2c-sysfs.rst | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/Documentation/i2c/i2c-sysfs.rst b/Documentation/i2c/i2c-sysfs.rst index 6b68b95cd427..d816a23b80f2 100644 --- a/Documentation/i2c/i2c-sysfs.rst +++ b/Documentation/i2c/i2c-sysfs.rst @@ -51,11 +51,10 @@ Google Pixel 3 phone for example:: ``i2c-2`` is an I2C bus whose number is 2, and ``2-0049`` is an I2C device on bus 2 address 0x49 bound with a kernel driver. -Terminologies -============= +Terminology +=========== -First, let us define a couple of terminologies to avoid confusions in the later -sections. +First, let us define some terms to avoid confusions in the later sections. (Physical) I2C Bus Controller ----------------------------- @@ -117,7 +116,7 @@ Walk through Logical I2C Bus For the following content, we will use a more complex I2C topology as an example. Here is a brief graph for the I2C topology. If you do not understand -this graph at the first glance, do not be afraid to continue reading this doc +this graph at first glance, do not be afraid to continue reading this doc and review it when you finish reading. :: From patchwork Mon Aug 8 14:17:08 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luca Ceresoli X-Patchwork-Id: 596134 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 39580C25B0C for ; Mon, 8 Aug 2022 14:18:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243504AbiHHOSE (ORCPT ); Mon, 8 Aug 2022 10:18:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46766 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243487AbiHHORy (ORCPT ); Mon, 8 Aug 2022 10:17:54 -0400 Received: from relay2-d.mail.gandi.net (relay2-d.mail.gandi.net [IPv6:2001:4b98:dc4:8::222]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0361F2651; Mon, 8 Aug 2022 07:17:48 -0700 (PDT) Received: from booty.fritz.box (unknown [77.244.183.192]) (Authenticated sender: luca.ceresoli@bootlin.com) by mail.gandi.net (Postfix) with ESMTPA id AD23A40020; Mon, 8 Aug 2022 14:17:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1659968267; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=pyimITfYwt3DejxDZgcbCvqHq6RQhBlBuA0ezeFDKiY=; b=NKVB+a7xZq38HyvuMUsGZ4uuCdObXTEDP7EACfzRBHTNybzlIdtguSWANv5Ge4gqM3NuP1 oaoXhG1Lh1T1aygrtWXyrgPSQuoE9x3EeQnTJLBqBTAmHqgOiugRaydA2HzE8EFdsklfGR yCIZ2DvovWl0Nr7AcsfeIEs0mAn51X8M4yNr/jg0AuwNFEyXrmj3gvFYHe4KoujytEcLN0 vOUuhWRDcWElPzlqxDgk5RZlWlHdc+5KbpgbCe1rDNNb8q8tT3t+QZJpAYhS+Gq+T3qn1w 6Q5KF5a4v/frDZcTA+CzGUi+97XBlmbLXqlJQQkx3GKYXT97nl3ulrMi/xhT0A== From: luca.ceresoli@bootlin.com To: linux-doc@vger.kernel.org, linux-i2c@vger.kernel.org Cc: Luca Ceresoli , Wolfram Sang , Peter Rosin , linux-kernel@vger.kernel.org Subject: [PATCH 9/9] docs: i2c: i2c-sysfs: fix hyperlinks Date: Mon, 8 Aug 2022 16:17:08 +0200 Message-Id: <20220808141708.1021103-10-luca.ceresoli@bootlin.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220808141708.1021103-1-luca.ceresoli@bootlin.com> References: <20220808141708.1021103-1-luca.ceresoli@bootlin.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org From: Luca Ceresoli dts files cannot be linked conveniently, thus replace them with literal formatting. The links to other rst pages are broken, fix them using the proper syntax. Fixes: 31df7195b100 ("Documentation: i2c: Add doc for I2C sysfs") Signed-off-by: Luca Ceresoli --- Documentation/i2c/i2c-sysfs.rst | 15 ++++----------- 1 file changed, 4 insertions(+), 11 deletions(-) diff --git a/Documentation/i2c/i2c-sysfs.rst b/Documentation/i2c/i2c-sysfs.rst index d816a23b80f2..b6d31290fc4b 100644 --- a/Documentation/i2c/i2c-sysfs.rst +++ b/Documentation/i2c/i2c-sysfs.rst @@ -99,9 +99,7 @@ Caveat This may be a confusing part for people who only know about the physical I2C design of a board. It is actually possible to rename the I2C bus physical number to a different number in logical I2C bus level in Device Tree Source (DTS) under -section ``aliases``. See -`arch/arm/boot/dts/nuvoton-npcm730-gsj.dts -<../../arch/arm/boot/dts/nuvoton-npcm730-gsj.dts>`_ +section ``aliases``. See ``arch/arm/boot/dts/nuvoton-npcm730-gsj.dts`` for an example of DTS file. Best Practice: **(To kernel software developers)** It is better to keep the I2C @@ -289,8 +287,7 @@ MUX channel 0, and all the way to ``i2c-19`` for the MUX channel 3. The kernel software developer is able to pin the fanout MUX channels to a static logical I2C bus number in the DTS. This doc will not go through the details on how to implement this in DTS, but we can see an example in: -`arch/arm/boot/dts/aspeed-bmc-facebook-wedge400.dts -<../../arch/arm/boot/dts/aspeed-bmc-facebook-wedge400.dts>`_ +``arch/arm/boot/dts/aspeed-bmc-facebook-wedge400.dts`` In the above example, there is an 8-channel I2C MUX at address 0x70 on physical I2C bus 2. The channel 2 of the MUX is defined as ``imux18`` in DTS, @@ -382,13 +379,9 @@ Sysfs for the I2C sensor device:: For more info on the Hwmon Sysfs, refer to the doc: -`Naming and data format standards for sysfs files -<../hwmon/sysfs-interface.rst>`_ +../hwmon/sysfs-interface.rst Instantiate I2C Devices in I2C Sysfs ------------------------------------ -Refer to the doc: - -`How to instantiate I2C devices, Method 4: Instantiate from user-space -`_ +Refer to section "Method 4: Instantiate from user-space" of instantiating-devices.rst