From patchwork Thu Jul 15 12:07:51 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andy Shevchenko X-Patchwork-Id: 12379887 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=-17.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 E1816C1B08C for ; Thu, 15 Jul 2021 12:08:23 +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 AACF0611C0 for ; Thu, 15 Jul 2021 12:08:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AACF0611C0 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-rockchip-bounces+linux-rockchip=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.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=xTGvNSrXu5EpS9uIh56/JaHTuNqrsk4pDoc53jvdGJQ=; b=QeiUYG5xq4nlJh Z/W/roK7UqvDGndru3UrLdAETYl/ww8MM3qBEkSaZd8QRqCvuh+Fd8DIDhhKvyAx4LYVKXZfdMspz OnAlDk+6krfMjXQfS7MkCOcHOmgKFCQQHQaog1fYZSY5x3/5Lkd17FdWVjeICAmxx8RAkXzpE4/2I hcqAra9eIYKS/iHWq39lqffAJWJDx17tVwaG7HuJV5yYX+BeE/rhy/jTmUcnmhrUbfY2XsAstxcaK /60P5RuEmCBQggAEiJvKNwN77rTotU5emzbfVEQBdP03CyAiTPeLQUl/d4zkGo7qr8CuT9+t+fXFQ ayqtlpjR2G8sH7pwEXJw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1m40A7-000hIY-GS; Thu, 15 Jul 2021 12:08:19 +0000 Received: from mga04.intel.com ([192.55.52.120]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1m409a-000h9c-4m; Thu, 15 Jul 2021 12:07:47 +0000 X-IronPort-AV: E=McAfee;i="6200,9189,10045"; a="208715427" X-IronPort-AV: E=Sophos;i="5.84,240,1620716400"; d="scan'208";a="208715427" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Jul 2021 05:07:41 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.84,240,1620716400"; d="scan'208";a="460371672" Received: from black.fi.intel.com ([10.237.72.28]) by orsmga008.jf.intel.com with ESMTP; 15 Jul 2021 05:07:39 -0700 Received: by black.fi.intel.com (Postfix, from userid 1003) id 52CD32CB; Thu, 15 Jul 2021 15:08:06 +0300 (EEST) From: Andy Shevchenko To: Andy Shevchenko , Heiko Stuebner , Elaine Zhang , Stephen Boyd , linux-kernel@vger.kernel.org, linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org Cc: Michael Turquette , Liu Ying Subject: [PATCH v1 2/3] clk: fractional-divider: Introduce NO_PRESCALER flag Date: Thu, 15 Jul 2021 15:07:51 +0300 Message-Id: <20210715120752.29174-2-andriy.shevchenko@linux.intel.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210715120752.29174-1-andriy.shevchenko@linux.intel.com> References: <20210715120752.29174-1-andriy.shevchenko@linux.intel.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210715_050746_233020_E7CF93E7 X-CRM114-Status: GOOD ( 15.53 ) X-BeenThere: linux-rockchip@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Upstream kernel work for Rockchip platforms List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-rockchip" Errors-To: linux-rockchip-bounces+linux-rockchip=archiver.kernel.org@lists.infradead.org The newly introduced flag, when set, makes the flow to skip the assumption that the caller will use an additional 2^scale prescaler to get the desired clock rate. Reported-by: Liu Ying Signed-off-by: Andy Shevchenko --- drivers/clk/clk-fractional-divider.c | 2 +- include/linux/clk-provider.h | 5 +++++ 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/clk/clk-fractional-divider.c b/drivers/clk/clk-fractional-divider.c index 535d299af646..b2f9aae9f172 100644 --- a/drivers/clk/clk-fractional-divider.c +++ b/drivers/clk/clk-fractional-divider.c @@ -84,7 +84,7 @@ void clk_fractional_divider_general_approximation(struct clk_hw *hw, * by (scale - fd->nwidth) bits. */ scale = fls_long(*parent_rate / rate - 1); - if (scale > fd->nwidth) + if (scale > fd->nwidth && !(fd->flags & CLK_FRAC_DIVIDER_NO_PRESCALER)) rate <<= scale - fd->nwidth; rational_best_approximation(rate, *parent_rate, diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h index d83b829305c0..f74d0afe275f 100644 --- a/include/linux/clk-provider.h +++ b/include/linux/clk-provider.h @@ -1001,6 +1001,10 @@ struct clk_hw *devm_clk_hw_register_fixed_factor(struct device *dev, * CLK_FRAC_DIVIDER_BIG_ENDIAN - By default little endian register accesses are * used for the divider register. Setting this flag makes the register * accesses big endian. + * CLK_FRAC_DIVIDER_NO_PRESCALER - By default the resulting rate may be shifted + * left by a few bits in case when the asked one is quite small to satisfy + * the desired range of denominator. If the caller wants to get the best + * rate without using an additional prescaler, this flag may be set. */ struct clk_fractional_divider { struct clk_hw hw; @@ -1022,6 +1026,7 @@ struct clk_fractional_divider { #define CLK_FRAC_DIVIDER_ZERO_BASED BIT(0) #define CLK_FRAC_DIVIDER_BIG_ENDIAN BIT(1) +#define CLK_FRAC_DIVIDER_NO_PRESCALER BIT(2) extern const struct clk_ops clk_fractional_divider_ops; struct clk *clk_register_fractional_divider(struct device *dev,