From patchwork Fri May 17 21:18:51 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tony Prisk X-Patchwork-Id: 2584501 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) by patchwork1.kernel.org (Postfix) with ESMTP id 11DF03FD4E for ; Fri, 17 May 2013 21:20:02 +0000 (UTC) Received: from merlin.infradead.org ([2001:4978:20e::2]) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1UdS3p-0004bN-Hs; Fri, 17 May 2013 21:19:34 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1UdS3e-0006nd-0K; Fri, 17 May 2013 21:19:22 +0000 Received: from server.prisktech.co.nz ([115.188.14.127]) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1UdS3Z-0006kP-J5 for linux-arm-kernel@lists.infradead.org; Fri, 17 May 2013 21:19:19 +0000 Received: from localhost.localdomain (unknown [192.168.0.102]) by server.prisktech.co.nz (Postfix) with ESMTP id 611B0FC0ECC; Sat, 18 May 2013 09:18:54 +1200 (NZST) From: Tony Prisk To: Mike Turquette Subject: [PATCH 3/4] clk: vt8500: Remove unnecessary divisor adjustment in vtwm_dclk_set_rate() Date: Sat, 18 May 2013 09:18:51 +1200 Message-Id: <1368825532-30917-4-git-send-email-linux@prisktech.co.nz> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1368825532-30917-1-git-send-email-linux@prisktech.co.nz> References: <1368825532-30917-1-git-send-email-linux@prisktech.co.nz> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130517_171918_069474_28B5B9D3 X-CRM114-Status: GOOD ( 12.51 ) X-Spam-Score: -2.5 (--) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-2.5 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.6 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: vt8500-wm8505-linux-kernel@googlegroups.com, Tony Prisk , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org The divisor adjustment code to ensure that a divisor is not rounded down, thereby giving a rate higher than requested, is unnecessary and in some instances results in the actual rate being much lower than requested due to rounding errors. The test is already performed in vtwm_dclk_round_rate(), which is always called when clk_set_rate is called. Due to rounding errors in the line: divisor = parent_rate / rate (clk-vt8500.c:160) we will sometimes end up adjusting the divisor twice - first in round_rate and then again in set_rate. This patch removes the test/adjustment in vtwm_dclk_set_rate. Signed-off-by: Tony Prisk --- drivers/clk/clk-vt8500.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/drivers/clk/clk-vt8500.c b/drivers/clk/clk-vt8500.c index ce401cf..82306f5 100644 --- a/drivers/clk/clk-vt8500.c +++ b/drivers/clk/clk-vt8500.c @@ -157,10 +157,6 @@ static int vt8500_dclk_set_rate(struct clk_hw *hw, unsigned long rate, divisor = parent_rate / rate; - /* If prate / rate would be decimal, incr the divisor */ - if (rate * divisor < parent_rate) - divisor++; - if (divisor == cdev->div_mask + 1) divisor = 0;