From patchwork Thu Aug 10 06:34:01 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Quentin Schulz X-Patchwork-Id: 9892801 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 9E53E60236 for ; Thu, 10 Aug 2017 06:35:29 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9438F28AAE for ; Thu, 10 Aug 2017 06:35:29 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 88AFD28AB8; Thu, 10 Aug 2017 06:35:29 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [65.50.211.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 1C7BE28AAE for ; Thu, 10 Aug 2017 06:35:28 +0000 (UTC) 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:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:References: In-Reply-To:Message-Id:Date:Subject:To:From:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=prcT6rggJ0vZEieRxYzX4yKFPVOLNEUtB673bwoJHwE=; b=ohTwrQL0Mm+1MQlKEl2w/w73Wo pLIhibko50Y28vGblwk/TU0hC1GaQ4CzOQp61simrz27TMieei0IqbMRM4naPvCG768B5Ofqx5r6h SNCUO9BcRGFzldz9T6POZIF/WmalvL6CNaU48EJtQxnGolnSxebNTC5qY+RQc9KM25v5C0Y8daoXR 3Z8WLfdYpesT5D+8sT5pn8VQqRr0BpRo3rJrIcNXMVLSYDd401ti62KkzSKpeKbmoWq9H4nn9YOij moYHMsNWatUj/VPnf9Akwc9GuAxeJCcjvx73wk8Ku+L1VvUUjJVdFyh+Frbpr9Y/On35lS/6lamyp huQ6WKeQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.87 #1 (Red Hat Linux)) id 1dfh42-0004qH-7n; Thu, 10 Aug 2017 06:35:26 +0000 Received: from mail.free-electrons.com ([62.4.15.54]) by bombadil.infradead.org with esmtp (Exim 4.87 #1 (Red Hat Linux)) id 1dfh3y-0003aY-6k for linux-arm-kernel@lists.infradead.org; Thu, 10 Aug 2017 06:35:24 +0000 Received: by mail.free-electrons.com (Postfix, from userid 110) id 6FBDA2096A; Thu, 10 Aug 2017 08:34:58 +0200 (CEST) Received: from localhost.localdomain (LStLambert-657-1-97-87.w90-63.abo.wanadoo.fr [90.63.216.87]) by mail.free-electrons.com (Postfix) with ESMTPSA id 0CDCA20936; Thu, 10 Aug 2017 08:34:58 +0200 (CEST) From: Quentin Schulz To: mturquette@baylibre.com, sboyd@codeaurora.org, robh+dt@kernel.org, mark.rutland@arm.com, lgirdwood@gmail.com, broonie@kernel.org, nicolas.ferre@microchip.com, alexandre.belloni@free-electrons.com, linux@armlinux.org.uk, boris.brezillon@free-electrons.com, perex@perex.cz, tiwai@suse.com Subject: [PATCH v5 1/7] clk: at91: clk-generated: remove useless divisor loop Date: Thu, 10 Aug 2017 08:34:01 +0200 Message-Id: X-Mailer: git-send-email 2.11.0 In-Reply-To: References: In-Reply-To: References: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20170809_233522_419034_F0C81488 X-CRM114-Status: GOOD ( 12.85 ) 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: thomas.petazzoni@free-electrons.com, devicetree@vger.kernel.org, alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org, Quentin Schulz , cyrille.pitchen@wedev4u.fr, linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP The driver requests the current clk rate of each of its parent clocks to decide whether a clock rate is suitable or not. It does not request determine_rate from a parent clock which could request a rate change in parent clock (i.e. there is no parent rate propagation). We know the rate we want (passed along req argument of the function) and the parent clock rate, thus we know the closest rounded divisor, we don't need to iterate over the available divisors to find the best one for a given clock. Signed-off-by: Quentin Schulz Acked-by: Boris Brezillon Acked-by: Nicolas Ferre --- drivers/clk/at91/clk-generated.c | 25 ++++++++++++------------- 1 file changed, 12 insertions(+), 13 deletions(-) diff --git a/drivers/clk/at91/clk-generated.c b/drivers/clk/at91/clk-generated.c index f0b7ae9..ef4b4e0 100644 --- a/drivers/clk/at91/clk-generated.c +++ b/drivers/clk/at91/clk-generated.c @@ -124,19 +124,18 @@ static int clk_generated_determine_rate(struct clk_hw *hw, (gck->range.max && min_rate > gck->range.max)) continue; - for (div = 1; div < GENERATED_MAX_DIV + 2; div++) { - tmp_rate = DIV_ROUND_CLOSEST(parent_rate, div); - tmp_diff = abs(req->rate - tmp_rate); - - if (best_diff < 0 || best_diff > tmp_diff) { - best_rate = tmp_rate; - best_diff = tmp_diff; - req->best_parent_rate = parent_rate; - req->best_parent_hw = parent; - } - - if (!best_diff || tmp_rate < req->rate) - break; + div = DIV_ROUND_CLOSEST(parent_rate, req->rate); + if (!div) + tmp_rate = parent_rate; + else + tmp_rate = parent_rate / div; + tmp_diff = abs(req->rate - tmp_rate); + + if (best_diff < 0 || best_diff > tmp_diff) { + best_rate = tmp_rate; + best_diff = tmp_diff; + req->best_parent_rate = parent_rate; + req->best_parent_hw = parent; } if (!best_diff)