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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 9CAACC7618B for ; Fri, 26 Jul 2019 14:01:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 765D82147A for ; Fri, 26 Jul 2019 14:01:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564149691; bh=gnAI7TMKcTyegOT0vgw/DwcaWyOPR9eTp+ndZdPTykA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=oPf9GXsT+EJbEzANZpssalkAoQ7k6UP8BtivIjNVxIAjaKVSYx/MBjSn1oY2y7dR5 9IlSqCNUQFZooU95jzT/Kxb6EWKlYggERgjR4zj1SDGPBrZ96SA6bu7MPlY9PlOUpd ud/vi77EcK2EndNed3rhtD6pAgKeOoYQ80TVpcSg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727412AbfGZNjp (ORCPT ); Fri, 26 Jul 2019 09:39:45 -0400 Received: from mail.kernel.org ([198.145.29.99]:45534 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727336AbfGZNjm (ORCPT ); Fri, 26 Jul 2019 09:39:42 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 56E9322BF5; Fri, 26 Jul 2019 13:39:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564148381; bh=gnAI7TMKcTyegOT0vgw/DwcaWyOPR9eTp+ndZdPTykA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RTywxIJfRzEKNevD5GBt33NkJzuRFMulWV1Gqit5nvuSUT1RXws7vWLAo5FlxzIgU cdWvDgCfg4noFAfyTWVSx2MqL4gdGB+QZyrxj5vEwPQ5wxFbz69Fvb8hz7hSIa7IY9 aBFJy8zN9a6ANGKkevX2VC/I/PObnyK9n/ayv8J0= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Jerome Brunet , Martin Blumenstingl , Sasha Levin , linux-amlogic@lists.infradead.org, linux-clk@vger.kernel.org Subject: [PATCH AUTOSEL 5.2 04/85] clk: meson: mpll: properly handle spread spectrum Date: Fri, 26 Jul 2019 09:38:14 -0400 Message-Id: <20190726133936.11177-4-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190726133936.11177-1-sashal@kernel.org> References: <20190726133936.11177-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jerome Brunet [ Upstream commit f9b3eeebef6aabaa37a351715374de53b6da860c ] 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") Tested-by: Martin Blumenstingl Signed-off-by: Jerome Brunet Signed-off-by: Sasha Levin --- 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 f76850d99e59..d3f42e086431 100644 --- a/drivers/clk/meson/clk-mpll.c +++ b/drivers/clk/meson/clk-mpll.c @@ -119,9 +119,12 @@ static int mpll_set_rate(struct clk_hw *hw, meson_parm_write(clk->map, &mpll->sdm, sdm); 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 integer divider part */ meson_parm_write(clk->map, &mpll->n2, n2); diff --git a/drivers/clk/meson/clk-mpll.h b/drivers/clk/meson/clk-mpll.h index cf79340006dd..0f948430fed4 100644 --- a/drivers/clk/meson/clk-mpll.h +++ b/drivers/clk/meson/clk-mpll.h @@ -23,6 +23,7 @@ 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