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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 73186C43381 for ; Fri, 22 Feb 2019 08:13:25 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3FBE020823 for ; Fri, 22 Feb 2019 08:13:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="NrSJjmI8"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="VTvOlSzq" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3FBE020823 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:Date:To:In-Reply-To:From:References: Message-ID:Subject:MIME-Version:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=iP8CS6/yKWiSmTVowdAbiKX+3vy+FfZKAXxS2TMHjsc=; b=NrSJjmI8m7UchS v1JzKuBu4BYQGeQImMCrHRqx7kPdD/KNlrH915d3lV/7tsFzj1VZIfivqVE54a9yg2NrvhETVd5YR 0RXfaYFMMn09jRdKv2kA/oJ59GX6xPP4ygt9jiZb/AzS6PwIokWfe9FoBuj8NusPMNHlKbZC2PrgK UKgnL5GFBIFvudFX7dNdOtg0tsdRAW4MZfdrl0+6JY/c9O2QyLCHDfHqvS5LZyvQgJRMg7etQPESZ 9pOEYfnmSoWWgXfuve8uCQ4/rMGqWnbBv8wo1afezEVNVuWLfUXjvHZExVEMtWREqOmr3PUBA0r7Y uvsTuIx3WHp3p/sgVwZg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gx5xR-0006aU-On; Fri, 22 Feb 2019 08:13:21 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1gx5xP-0006aC-Lr for linux-arm-kernel@lists.infradead.org; Fri, 22 Feb 2019 08:13:20 +0000 Received: from localhost (unknown [104.132.0.74]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2478120823; Fri, 22 Feb 2019 08:13:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550823199; bh=ljvD/aGj+6Hipv0rUE56d5fYerjq/aYHjKYQ9G5T5gA=; h=Subject:References:From:In-Reply-To:To:Cc:Date:From; b=VTvOlSzqBB5QzLrdkk1Uc5Z8hrhsfHRq3W+a+QyxZFSZX/pM1tnFccoornqJk2S7S HtiKbukXqD2Jc42uRtF/un1afpACYWQbk4reVruBhvyYB/7PvGaPw2qTwCntsaQUBe jz7sTc/80zB3f0Z+81nA9nn2w2CohYTyRPlR+UIk= MIME-Version: 1.0 Subject: Re: [PATCH v2] clk: fractional-divider: check parent rate only if flag is set Message-ID: <155082319829.77512.7935951458664373330@swboyd.mtv.corp.google.com> User-Agent: alot/0.8 References: <20190210153806.24201-1-katsuhiro@katsuster.net> From: Stephen Boyd In-Reply-To: <20190210153806.24201-1-katsuhiro@katsuster.net> To: Katsuhiro Suzuki , Michael Turquette , linux-clk@vger.kernel.org Date: Fri, 22 Feb 2019 00:13:18 -0800 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190222_001319_731590_5BD4066A X-CRM114-Status: UNSURE ( 9.48 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Katsuhiro Suzuki , Heiko Stuebner , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Quoting Katsuhiro Suzuki (2019-02-10 07:38:06) > Custom approximation of fractional-divider may not need parent clock > rate checking. For example Rockchip SoCs work fine using grand parent > clock rate even if target rate is greater than parent. > > This patch checks parent clock rate only if CLK_SET_RATE_PARENT flag > is set. > > For detailed example, clock tree of Rockchip I2S audio hardware. > - Clock rate of CPLL is 1.2GHz, GPLL is 491.52MHz. > - i2s1_div is integer divider can divide N (N is 1~128). > Input clock is CPLL or GPLL. Initial divider value is N = 1. > Ex) PLL = CPLL, N = 10, i2s1_div output rate is > CPLL / 10 = 1.2GHz / 10 = 120MHz > - i2s1_frac is fractional divider can divide input to x/y, x and > y are 16bit integer. > > CPLL --> | selector | ---> i2s1_div -+--> | selector | --> I2S1 MCLK Applied to clk-next but I made the function into a macro because I don't see the benefit to exporting such a simple thing. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel