From mboxrd@z Thu Jan 1 00:00:00 1970 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 7402AC43219 for ; Thu, 5 May 2022 13:43:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238690AbiEENrN (ORCPT ); Thu, 5 May 2022 09:47:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59166 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1379855AbiEENrF (ORCPT ); Thu, 5 May 2022 09:47:05 -0400 Received: from fllv0015.ext.ti.com (fllv0015.ext.ti.com [198.47.19.141]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E9FE257999; Thu, 5 May 2022 06:43:24 -0700 (PDT) Received: from fllv0035.itg.ti.com ([10.64.41.0]) by fllv0015.ext.ti.com (8.15.2/8.15.2) with ESMTP id 245DhA3u030876; Thu, 5 May 2022 08:43:10 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1651758190; bh=7PpGp+IxjY/mFC2wCH1dJ/EU5sBQTGAt350jNpBo3oU=; h=From:To:CC:Subject:Date:In-Reply-To:References; b=h2aKHfebjZGw0M5mTyx/EmM6CIDH2KRf6D6PMo2jfhRwr7+GFLgmlQLJ+Ql2vOuUn mCIg/J0s3GM/9h31tAb4eqOENIxWoUkV+9j+APvQN8qPl0cV5eKhJhn7x/BNoxyJUq 0l6ewkMnQF4+Kbpq0brtGnlQK8mzkRA2VfIknR+4= Received: from DFLE114.ent.ti.com (dfle114.ent.ti.com [10.64.6.35]) by fllv0035.itg.ti.com (8.15.2/8.15.2) with ESMTPS id 245DhA6J053453 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 5 May 2022 08:43:10 -0500 Received: from DFLE101.ent.ti.com (10.64.6.22) by DFLE114.ent.ti.com (10.64.6.35) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2308.14; Thu, 5 May 2022 08:43:10 -0500 Received: from fllv0039.itg.ti.com (10.64.41.19) by DFLE101.ent.ti.com (10.64.6.22) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2308.14 via Frontend Transport; Thu, 5 May 2022 08:43:09 -0500 Received: from localhost (ileax41-snat.itg.ti.com [10.172.224.153]) by fllv0039.itg.ti.com (8.15.2/8.15.2) with ESMTP id 245Dh939104707; Thu, 5 May 2022 08:43:09 -0500 From: Aradhya Bhatia To: Vignesh Raghavendra CC: Nishanth Menon , Rob Herring , Linux ARM Kernel List , Devicetree List , Linux Kernel List , Aradhya Bhatia , Rahul T R Subject: [PATCH v2 3/4] arm64: dts: ti: k3-am625-sk: Update main-i2c1 frequency Date: Thu, 5 May 2022 19:13:02 +0530 Message-ID: <20220505134303.23208-4-a-bhatia1@ti.com> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220505134303.23208-1-a-bhatia1@ti.com> References: <20220505134303.23208-1-a-bhatia1@ti.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Update the main-i2c1 frequency from 400KHz to 100KHz. There are 2 devices on the i2c-1 bus. An IO-Expander and an HDMI TX. Both of these are capable of servicing i2c upto a max frequency of 400KHz. However, below warning log shows up while running any userspace application that uses the HDMI display when the main-i2c1 frequency is set at 400KHz. [ 985.773431] omap_i2c 20010000.i2c: controller timed out With some further tests using 2 frequencies, 100 KHz and 400KHz across different HDMI cable & monitor setups, it was observed that, - i2c frequency of 400KHz works fine with standard good quality HDMI cables with branded displays. It will show the controller timeout warnings only when a sub-standard / generic HDMI cable is being used. - Using 100KHz for i2c frequency, stops the warning from showing up for the generic HDMI cables as well. Since, the IO-Expander is the only other component on that i2c bus and we are not performing any intensive operations on it, it would be safe to set the i2c frequency at 100KHz in order to support a broader variety of HDMI cables. Signed-off-by: Aradhya Bhatia Reviewed-by: Rahul T R --- arch/arm64/boot/dts/ti/k3-am625-sk.dts | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/boot/dts/ti/k3-am625-sk.dts b/arch/arm64/boot/dts/ti/k3-am625-sk.dts index ab3d90d358ee..96414c5dacf7 100644 --- a/arch/arm64/boot/dts/ti/k3-am625-sk.dts +++ b/arch/arm64/boot/dts/ti/k3-am625-sk.dts @@ -357,7 +357,7 @@ &main_i2c0 { &main_i2c1 { pinctrl-names = "default"; pinctrl-0 = <&main_i2c1_pins_default>; - clock-frequency = <400000>; + clock-frequency = <100000>; exp1: gpio@22 { compatible = "ti,tca6424"; -- 2.36.0