From patchwork Sat Aug 8 16:10:27 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Russell King X-Patchwork-Id: 6975441 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 64A309F402 for ; Sat, 8 Aug 2015 16:14:57 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 76EDE205F7 for ; Sat, 8 Aug 2015 16:14:56 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 9533E20562 for ; Sat, 8 Aug 2015 16:14:55 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZO6k6-0006Mb-Ld; Sat, 08 Aug 2015 16:13:06 +0000 Received: from pandora.arm.linux.org.uk ([2001:4d48:ad52:3201:214:fdff:fe10:1be6]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZO6ib-0004Hm-15 for linux-arm-kernel@lists.infradead.org; Sat, 08 Aug 2015 16:11:40 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=arm.linux.org.uk; s=pandora-2014; h=Date:Sender:Message-Id:Content-Type:Content-Transfer-Encoding:MIME-Version:Subject:Cc:To:From:References:In-Reply-To; bh=yzONKHWclhtOC4z3dTOmAYY+LVxtnNaVDvt3pjfiNvQ=; b=ojPPonY+6SgA2jDjc6jndBBq1EzlfzWIDlIugt+ie4BiiGZ6VlOIuHHJJHKoLUaQ4No1cZ75qcZ3tUgtupVqaUcI4+vQGDI05pqpIYG1QlSZ4NkOarWhKaVl+sqTuc0/zThoPoqSiSkT5o7c93yaaoPY+tysYT8t/JzzH1fOaY8=; Received: from e0022681537dd.dyn.arm.linux.org.uk ([2001:4d48:ad52:3201:222:68ff:fe15:37dd]:60400 helo=rmk-PC.arm.linux.org.uk) by pandora.arm.linux.org.uk with esmtpsa (TLSv1:AES128-SHA:128) (Exim 4.82_1-5b7a7c0-XX) (envelope-from ) id 1ZO6he-0006T5-4m; Sat, 08 Aug 2015 17:10:34 +0100 Received: from rmk by rmk-PC.arm.linux.org.uk with local (Exim 4.82_1-5b7a7c0-XX) (envelope-from ) id 1ZO6hX-0003NK-0H; Sat, 08 Aug 2015 17:10:27 +0100 In-Reply-To: <20150808160936.GN7557@n2100.arm.linux.org.uk> References: <20150808160936.GN7557@n2100.arm.linux.org.uk> From: Russell King To: linux-rockchip@lists.infradead.org, alsa-devel@alsa-project.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH 5/9] drm: bridge/dw_hdmi: avoid being recursive in N calculation MIME-Version: 1.0 Content-Disposition: inline Message-Id: Date: Sat, 08 Aug 2015 17:10:27 +0100 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150808_091135_223058_7CFFA5BC X-CRM114-Status: GOOD ( 11.13 ) X-Spam-Score: -2.4 (--) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Fabio Estevam , Takashi Iwai , Sascha Hauer , Jaroslav Kysela , David Airlie , Mark Brown , Philipp Zabel , Yakir Yang , Andy Yan , Jon Nettleton Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.5 required=5.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_MED,RP_MATCHES_RCVD,T_DKIM_INVALID,UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP There's no need to be recursive when computing the N value for the ACR packet - we can instead calculate the multiplier prior to our switch() based lookup, and multiply the N value appropriately afterwards. Signed-off-by: Russell King Reviewed-by: Douglas Anderson Tested-by: Douglas Anderson --- drivers/gpu/drm/bridge/dw_hdmi.c | 25 +++++++++---------------- 1 file changed, 9 insertions(+), 16 deletions(-) diff --git a/drivers/gpu/drm/bridge/dw_hdmi.c b/drivers/gpu/drm/bridge/dw_hdmi.c index a8b243278774..f0e6059f818a 100644 --- a/drivers/gpu/drm/bridge/dw_hdmi.c +++ b/drivers/gpu/drm/bridge/dw_hdmi.c @@ -221,6 +221,12 @@ static unsigned int hdmi_compute_n(unsigned int freq, unsigned long pixel_clk, unsigned int ratio) { unsigned int n = (128 * freq) / 1000; + unsigned int mult = 1; + + while (freq > 48000) { + mult *= 2; + freq /= 2; + } switch (freq) { case 32000: @@ -232,6 +238,7 @@ static unsigned int hdmi_compute_n(unsigned int freq, unsigned long pixel_clk, n = 11648; else n = 4096; + n *= mult; break; case 44100: @@ -243,6 +250,7 @@ static unsigned int hdmi_compute_n(unsigned int freq, unsigned long pixel_clk, n = (ratio == 150) ? 17836 : 8918; else n = 6272; + n *= mult; break; case 48000: @@ -256,22 +264,7 @@ static unsigned int hdmi_compute_n(unsigned int freq, unsigned long pixel_clk, n = (ratio == 150) ? 11648 : 5824; else n = 6144; - break; - - case 88200: - n = hdmi_compute_n(44100, pixel_clk, ratio) * 2; - break; - - case 96000: - n = hdmi_compute_n(48000, pixel_clk, ratio) * 2; - break; - - case 176400: - n = hdmi_compute_n(44100, pixel_clk, ratio) * 4; - break; - - case 192000: - n = hdmi_compute_n(48000, pixel_clk, ratio) * 4; + n *= mult; break; default: