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=-9.0 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 05EF5C43381 for ; Fri, 29 Mar 2019 15:33:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C40F1218AC for ; Fri, 29 Mar 2019 15:33:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=baylibre-com.20150623.gappssmtp.com header.i=@baylibre-com.20150623.gappssmtp.com header.b="JFlOjZCu" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728945AbfC2Pdj (ORCPT ); Fri, 29 Mar 2019 11:33:39 -0400 Received: from mail-wr1-f67.google.com ([209.85.221.67]:43237 "EHLO mail-wr1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729654AbfC2Pdg (ORCPT ); Fri, 29 Mar 2019 11:33:36 -0400 Received: by mail-wr1-f67.google.com with SMTP id k17so3088975wrx.10 for ; Fri, 29 Mar 2019 08:33:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=baylibre-com.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=GPit8v+Q7DtocOZEXU4jiFZqiXXyIE54mF68t3axNAg=; b=JFlOjZCuBF4USFLbmGUtrAoPYawoUOO5wzWamoY/Tyuudb+4Gu2K4bS484QHyG0il3 GOq9ccl7t08dBEtKgSNnmy554RdlGvJs9vcKT20n7kZq2+WSD4fjeic11WWGQudS2z+9 L5jhk/mBV3ZShqtJnnDPv+b8OcPLQ0G9GXNXSffdzMc+AWP3KjrQkJlnFormY9M74haX ijyHZ5Pab+pbsIfSSR7/1q0WElWoAPw4ob70hS2m3xPFQkSZb8bIkbgrUXPnicKQE0ss gmT/YLwB7QlBtEe9HfXfZF1mv7UUt+4FjMoYv7KcugC+hW6TEZ/VDjtU/WSlEdnPIm1E 8FIQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=GPit8v+Q7DtocOZEXU4jiFZqiXXyIE54mF68t3axNAg=; b=lG5V6utYQEU87XYPEnknXC2zYi3JJlWp8r7vAu8nUv2ySwaV8HpakfPnqaaKkmlsuc G9oKPIClrU7v6FyDCZy4jGXtO5+CRaYxTijlnhITB5xIgdoj0IW2vYzHxUzDDlTe23oU nIVfWCHKfFN78CFSqQUYyQ1FrkWvprJJAAAjhtGlxwuL4k2Lq2GNqIKTReN6x64lTxTk i2MHojD7llJrqCtlBEm0XPHJaXWi70eFZZvzDNwn4081m7BPBSj28TemvYMhFczNJ5LG V+DT7uyT3lszgCNJua6uVFc9bxM1HdVKNISaCyP2qKst6yAC25AlnmYFz6B9wdNPdxkx Cj6w== X-Gm-Message-State: APjAAAU6dNFdulnNG08ql8vlT7OhBT/aDXNrFQLLzY7IY/+IvaRK0/EQ EiKX/3TPQTCIyAZErmQTeEUD8w== X-Google-Smtp-Source: APXvYqwGgnk+y67GmSfAmgzYWFvp/+mQnKnCZOHwrdAllmxhqeMRmGvfJSQ3hwjYPPM9OpM+pidCzA== X-Received: by 2002:adf:db10:: with SMTP id s16mr23886951wri.181.1553873614583; Fri, 29 Mar 2019 08:33:34 -0700 (PDT) Received: from boomer.local ([2a01:e34:eeb6:4690:106b:bae3:31ed:7561]) by smtp.googlemail.com with ESMTPSA id s18sm1930173wmc.41.2019.03.29.08.33.33 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 29 Mar 2019 08:33:34 -0700 (PDT) From: Jerome Brunet To: Neil Armstrong Cc: Jerome Brunet , linux-amlogic@lists.infradead.org, linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 1/3] clk: meson: mpll: properly handle spread spectrum Date: Fri, 29 Mar 2019 16:33:23 +0100 Message-Id: <20190329153325.23869-2-jbrunet@baylibre.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190329153325.23869-1-jbrunet@baylibre.com> References: <20190329153325.23869-1-jbrunet@baylibre.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The bit 'SSEN' available on some MPLL DSS outputs is not related to the fractional part of the divider but to the function called 'Spread Spectrum'. This function might be used to solve EM issues by adding a jitter on clock signal. This widens the signal spectrum and weakens the peaks in it. While spread spectrum might be useful for some application, it is problematic for others, such as audio. This patch introduce a new flag to the MPLL driver to enable (or not) the spread spectrum function. Fixes: 1f737ffa13ef ("clk: meson: mpll: fix mpll0 fractional part ignored") Signed-off-by: Jerome Brunet --- drivers/clk/meson/clk-mpll.c | 9 ++++++--- drivers/clk/meson/clk-mpll.h | 1 + 2 files changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/clk/meson/clk-mpll.c b/drivers/clk/meson/clk-mpll.c index 64d31c8ba3d0..2d39a8bc367c 100644 --- a/drivers/clk/meson/clk-mpll.c +++ b/drivers/clk/meson/clk-mpll.c @@ -141,9 +141,12 @@ static void mpll_init(struct clk_hw *hw) /* Enable the fractional part */ meson_parm_write(clk->map, &mpll->sdm_en, 1); - /* Set additional fractional part enable if required */ - if (MESON_PARM_APPLICABLE(&mpll->ssen)) - meson_parm_write(clk->map, &mpll->ssen, 1); + /* Set spread spectrum if possible */ + if (MESON_PARM_APPLICABLE(&mpll->ssen)) { + unsigned int ss = + mpll->flags & CLK_MESON_MPLL_SPREAD_SPECTRUM ? 1 : 0; + meson_parm_write(clk->map, &mpll->ssen, ss); + } /* Set the magic misc bit if required */ if (MESON_PARM_APPLICABLE(&mpll->misc)) diff --git a/drivers/clk/meson/clk-mpll.h b/drivers/clk/meson/clk-mpll.h index 2925fb939fdd..a991d568c43a 100644 --- a/drivers/clk/meson/clk-mpll.h +++ b/drivers/clk/meson/clk-mpll.h @@ -25,6 +25,7 @@ struct meson_clk_mpll_data { }; #define CLK_MESON_MPLL_ROUND_CLOSEST BIT(0) +#define CLK_MESON_MPLL_SPREAD_SPECTRUM BIT(1) extern const struct clk_ops meson_clk_mpll_ro_ops; extern const struct clk_ops meson_clk_mpll_ops; -- 2.20.1