From patchwork Sun Jan 15 10:15:48 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Heiner Kallweit X-Patchwork-Id: 643268 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 D92D9C46467 for ; Sun, 15 Jan 2023 10:18:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230462AbjAOKSq (ORCPT ); Sun, 15 Jan 2023 05:18:46 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50132 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230145AbjAOKSa (ORCPT ); Sun, 15 Jan 2023 05:18:30 -0500 Received: from mail-wr1-x42e.google.com (mail-wr1-x42e.google.com [IPv6:2a00:1450:4864:20::42e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C2794CDE3; Sun, 15 Jan 2023 02:18:29 -0800 (PST) Received: by mail-wr1-x42e.google.com with SMTP id k8so10365544wrc.9; Sun, 15 Jan 2023 02:18:29 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:in-reply-to:references:cc:to:from :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=/D0U6ZSa9ufXqRencjxkQFzJOdEXcs/cpW2jU/kZH/M=; b=K9pasKsSYWaBapGarM+zzgGQVplz5o57CJb32ZxlQ14rAfHqBMOGMYSVFnHsx7qJ9G VXRpCU0JQqDhgNsOWFInXfYDxCrZc+FcBOCUqbQ6WmqmrdTyjNHh/tCx13x89CZR6EAE IGuhsdjtoLjWxubUnetxlEI1071gXYO2zqwhyhofHnHDKXpIiedt9xi5t5jztD+Z/ZU8 Q0BBcMrGrEAK9LnEqEKd2B+AAJfNjOQ3s7gvmnUoL2sOVkFvGYLYPCNggVdGrk7TXpLu VOjtLJP03FWAtC1lTm3mlBibXHdS7GDOXvJuS+CqumZWGTFudkRvMmqMPIENZGd6THHV rXQA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:references:cc:to:from :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=/D0U6ZSa9ufXqRencjxkQFzJOdEXcs/cpW2jU/kZH/M=; b=NQy97VrQR8yabPuPMQ7cnmdD0Hy4bB2baOUeFFX11BFm4TutbDjSK7XvjH+e+7xOBd Mk9OjhCyGIi5P8PgrTfFOg31j5KbO89GfEgh7EAO20YYdfz/bUzyEzIKWlILCr0VcaPL PdhsLcAjl/pwV1sMfv/IdgSblefN3EohOlDwvgm/kpmEmrN7KQM9+TENZnMlAqZz1JfO MCpld3rbx+2MbX3o9Uu8Q+xha3SPqY7G4kWOjGMH6oXmqHKd+NpW9wAe2CMbfyrP1bZp dP52sXCFo9fIr3C+fI5T9gKd4MwUz65PhIzRCgFjxi9B25BxctSsJyjHq5pYlnL7k8fl rCxQ== X-Gm-Message-State: AFqh2kqUeQZ8F/g+4wt3wUEu68wov5InN54Z5GzozVrAn1wQPkXTCR+C yFy4Pb5I6VtZJ325q1w1TUYlKFjt9uk= X-Google-Smtp-Source: AMrXdXv48t+zyOW+TLe3yWdXReBPlpJ/rytYi71Z/PeQUGAPaIFkFLeYZzO7pVES7BjHKIz5LCALiw== X-Received: by 2002:a5d:4b0f:0:b0:2bd:c4ea:3b59 with SMTP id v15-20020a5d4b0f000000b002bdc4ea3b59mr10674279wrq.0.1673777908265; Sun, 15 Jan 2023 02:18:28 -0800 (PST) Received: from ?IPV6:2a01:c22:6e61:8c00:154f:326e:8d45:8ce7? (dynamic-2a01-0c22-6e61-8c00-154f-326e-8d45-8ce7.c22.pool.telefonica.de. [2a01:c22:6e61:8c00:154f:326e:8d45:8ce7]) by smtp.googlemail.com with ESMTPSA id l4-20020a05600012c400b002bbb2d43f65sm20419613wrx.14.2023.01.15.02.18.27 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 15 Jan 2023 02:18:27 -0800 (PST) Message-ID: Date: Sun, 15 Jan 2023 11:15:48 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.6.1 Subject: [PATCH v3 2/3] i2c: algo: bit: allow getsda to be NULL Content-Language: en-US From: Heiner Kallweit To: Rob Herring , Krzysztof Kozlowski , Wolfram Sang Cc: "linux-i2c@vger.kernel.org" , "devicetree@vger.kernel.org" References: <3a5545f3-f858-2c80-8bd4-2e0d401a1dc0@gmail.com> In-Reply-To: <3a5545f3-f858-2c80-8bd4-2e0d401a1dc0@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org This is in preparation of supporting write-only SDA in i2c-gpio. Signed-off-by: Heiner Kallweit --- v3: - check for adap->getsda in readbytes() - align warning message level for info on missing getscl/getsda --- drivers/i2c/algos/i2c-algo-bit.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/drivers/i2c/algos/i2c-algo-bit.c b/drivers/i2c/algos/i2c-algo-bit.c index fc90293af..a1b822723 100644 --- a/drivers/i2c/algos/i2c-algo-bit.c +++ b/drivers/i2c/algos/i2c-algo-bit.c @@ -184,8 +184,9 @@ static int i2c_outb(struct i2c_adapter *i2c_adap, unsigned char c) /* read ack: SDA should be pulled down by slave, or it may * NAK (usually to report problems with the data we wrote). + * Always report ACK if SDA is write-only. */ - ack = !getsda(adap); /* ack: sda is pulled low -> success */ + ack = !adap->getsda || !getsda(adap); /* ack: sda is pulled low -> success */ bit_dbg(2, &i2c_adap->dev, "i2c_outb: 0x%02x %s\n", (int)c, ack ? "A" : "NA"); @@ -232,6 +233,10 @@ static int test_bus(struct i2c_adapter *i2c_adap) const char *name = i2c_adap->name; int scl, sda, ret; + /* Testing not possible if both pins are write-only. */ + if (adap->getscl == NULL && adap->getsda == NULL) + return 0; + if (adap->pre_xfer) { ret = adap->pre_xfer(i2c_adap); if (ret < 0) @@ -420,6 +425,10 @@ static int readbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg) unsigned char *temp = msg->buf; int count = msg->len; const unsigned flags = msg->flags; + struct i2c_algo_bit_data *adap = i2c_adap->algo_data; + + if (!adap->getsda) + return -EOPNOTSUPP; while (count > 0) { inval = i2c_inb(i2c_adap); @@ -670,8 +679,11 @@ static int __i2c_bit_add_bus(struct i2c_adapter *adap, if (ret < 0) return ret; - /* Complain if SCL can't be read */ + if (bit_adap->getsda == NULL) + dev_warn(&adap->dev, "Not I2C compliant: can't read SDA\n"); + if (bit_adap->getscl == NULL) { + /* Complain if SCL can't be read */ dev_warn(&adap->dev, "Not I2C compliant: can't read SCL\n"); dev_warn(&adap->dev, "Bus may be unreliable\n"); }