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 X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 15F46C43215 for ; Tue, 19 Nov 2019 12:03:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EC11321850 for ; Tue, 19 Nov 2019 12:03:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727833AbfKSMDn (ORCPT ); Tue, 19 Nov 2019 07:03:43 -0500 Received: from foss.arm.com ([217.140.110.172]:51560 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725280AbfKSMDm (ORCPT ); Tue, 19 Nov 2019 07:03:42 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 24E61C86; Tue, 19 Nov 2019 04:03:42 -0800 (PST) Received: from donnerap.arm.com (donnerap.cambridge.arm.com [10.1.197.44]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id BDE143F703; Tue, 19 Nov 2019 04:03:40 -0800 (PST) From: Andre Przywara To: Liviu Dudau , Sudeep Holla , Lorenzo Pieralisi Cc: Rob Herring , Mark Rutland , linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] arm64: dts: arm: juno: Fix UART frequency Date: Tue, 19 Nov 2019 12:03:31 +0000 Message-Id: <20191119120331.28243-1-andre.przywara@arm.com> X-Mailer: git-send-email 2.17.1 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Older versions of the Juno *SoC* TRM [1] recommended that the UART clock source should be 7.2738 MHz, whereas the *system* TRM [2] stated a more correct value of 7.3728 MHz. Somehow the wrong value managed to end up in our DT. Doing a prime factorisation, a modulo divide by 115200 and trying to buy a 7.2738 MHz crystal at your favourite electronics dealer suggest that the old value was actually a typo. The actual UART clock is driven by a PLL, configured via a parameter in some board.txt file in the firmware, which reads 7.37 MHz (sic!). Fix this to correct the baud rate divisor calculation on the Juno board. Signed-off-by: Andre Przywara [1] http://infocenter.arm.com/help/topic/com.arm.doc.ddi0515b.b/DDI0515B_b_juno_arm_development_platform_soc_trm.pdf [2] http://infocenter.arm.com/help/topic/com.arm.doc.100113_0000_07_en/arm_versatile_express_juno_development_platform_(v2m_juno)_technical_reference_manual_100113_0000_07_en.pdf --- arch/arm64/boot/dts/arm/juno-clocks.dtsi | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm64/boot/dts/arm/juno-clocks.dtsi b/arch/arm64/boot/dts/arm/juno-clocks.dtsi index e5e265dfa902..2870b5eeb198 100644 --- a/arch/arm64/boot/dts/arm/juno-clocks.dtsi +++ b/arch/arm64/boot/dts/arm/juno-clocks.dtsi @@ -8,10 +8,10 @@ */ / { /* SoC fixed clocks */ - soc_uartclk: refclk7273800hz { + soc_uartclk: refclk7372800hz { compatible = "fixed-clock"; #clock-cells = <0>; - clock-frequency = <7273800>; + clock-frequency = <7372800>; clock-output-names = "juno:uartclk"; }; -- 2.17.1