From patchwork Thu Aug 16 07:16:39 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Masahiro Yamada X-Patchwork-Id: 144322 Delivered-To: patch@linaro.org Received: by 2002:a2e:9754:0:0:0:0:0 with SMTP id f20-v6csp1729525ljj; Thu, 16 Aug 2018 00:17:50 -0700 (PDT) X-Google-Smtp-Source: AA+uWPwjgTCfCEUN3TH0snFWElVq/PkiyOXjh1A2WK63XSdVv2owPGu+4clP8JGmg9tA2zbYGnOB X-Received: by 2002:a17:902:7793:: with SMTP id o19-v6mr28185336pll.306.1534403870658; Thu, 16 Aug 2018 00:17:50 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1534403870; cv=none; d=google.com; s=arc-20160816; b=hrjcepS83IyuD8431SKKPveXT3z8sC5Q3V5824Yr+Xdxf7zCmdA/GJrKLkS4mzwhaf gLattJCfEYyNjNfK1fSgGroDfb3uUrZE0Z0m8cqZhaph2hqKkDlBAwaYnJ/xBgnxTZAw PgFOC1QkXZsFfbraH4VDzW6N5KgdQrl2s/Cl1iLIENdFOGe3qfR36nSvUatJ+jLnQS7b JOOYRFqxmc4qFYm4IfwgkR18FdHHuYnCMMeuDWLzP88eIOqj/XdV0kTXV1bcCGyLuqJ4 luWrvA+ZkjuqmeFLnmc02z2++ZSEnSlW/96SgnDxEHnbSeb/YzbR1QEa3FkkPp+ApzU7 cMOQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:references:in-reply-to:message-id:date :subject:cc:to:from:dkim-signature:dkim-filter :arc-authentication-results; bh=Yzpwtd3BlQ9HcQbHX4J5Wqq0RNmvS0W30hL7Io/DvEE=; b=vC7QJ4f49KHaKDUcMKj7Uvqhj5UQ1bHwdIHSYe3Qxc/iiXNI468YQ5aUmC35eOxNOA iPqShuQnPnqH/xFhH4trkzxU7ph9lui7Mf71dVk7afMnn93qV/QlZuPJocsFEC22tv9C /kGG3nMsq2SCiN0RsO3ewSTH+FKjTeCDyQd9RSsXaWf4sbv9+jW610Z3aw+ZRY0FWQfj x9BBYqJ0mmbiyp7HcVJS8X3eGZi/TRX2wxzE/eutZSi5kgD3Ps8FlitS/vXPXUJK0IcK Ll4VxHMOOGe/l0+F1ylftixMuhoFMm1Q2hXbdrWh/PfxpKyvXHEc7ALhE4oolvRSU2V2 kcXg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@nifty.com header.s=dec2015msa header.b=sHR03fT0; spf=pass (google.com: best guess record for domain of linux-mmc-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-mmc-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id f12-v6si24878828pgm.601.2018.08.16.00.17.50; Thu, 16 Aug 2018 00:17:50 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-mmc-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@nifty.com header.s=dec2015msa header.b=sHR03fT0; spf=pass (google.com: best guess record for domain of linux-mmc-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-mmc-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389279AbeHPKOQ (ORCPT + 5 others); Thu, 16 Aug 2018 06:14:16 -0400 Received: from conuserg-09.nifty.com ([210.131.2.76]:17406 "EHLO conuserg-09.nifty.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389275AbeHPKOP (ORCPT ); Thu, 16 Aug 2018 06:14:15 -0400 Received: from grover.tkatk1.zaq.ne.jp (zaqdadce369.zaq.ne.jp [218.220.227.105]) (authenticated) by conuserg-09.nifty.com with ESMTP id w7G7Gu2N008336; Thu, 16 Aug 2018 16:17:02 +0900 DKIM-Filter: OpenDKIM Filter v2.10.3 conuserg-09.nifty.com w7G7Gu2N008336 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nifty.com; s=dec2015msa; t=1534403822; bh=Yzpwtd3BlQ9HcQbHX4J5Wqq0RNmvS0W30hL7Io/DvEE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sHR03fT0j4Qg1LvMOcw36yE0ivSm/ZzTUIckcwPjBsKt2KPG9hZ0+7/hpyNPWRXh2 GXODYuDOIzQlSxSnfGNi7gMpjsz1lNWDKIczN029Fmvy1MqySnLbfv4jRV+Bzwdky+ HkzzUaov0ja7nMos2fKjvARja8XsFvnhXx2xip6ONCrl0yWiLVpB/7HS1HrkFjUv+u 9ARRz1si8j+PixeeOioOLKc3/ogN6ghDH6lAcbNp+xGUmG8kaOR2O/nfAAcR0KIlrn iqDDryxqglQ4CLjTIQqswQQDME5d2/jpcJLPxiBagDu49hyN7I0YI2EtREdRe/3y8Z 9sv+qZSdYdziA== X-Nifty-SrcIP: [218.220.227.105] From: Masahiro Yamada To: linux-mmc@vger.kernel.org, Wolfram Sang Cc: Masami Hiramatsu , Jassi Brar , Ulf Hansson , linux-renesas-soc@vger.kernel.org, Masahiro Yamada Subject: [PATCH v2 7/7] mmc: tmio: refactor CLK_CTL bit calculation Date: Thu, 16 Aug 2018 16:16:39 +0900 Message-Id: <1534403799-10594-8-git-send-email-yamada.masahiro@socionext.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1534403799-10594-1-git-send-email-yamada.masahiro@socionext.com> References: <1534403799-10594-1-git-send-email-yamada.masahiro@socionext.com> Sender: linux-mmc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mmc@vger.kernel.org for (clk = 0x80000080; new_clock >= (clock << 1); clk >>= 1) clock <<= 1; ... is too tricky, hence I replaced with roundup_pow_of_two(divisor) >> 2 '(clk >> 22) & 0x1' is the bit test for the 1/1 divisor, but it is not clear. 'divisor <= 1' is easier to understand. Signed-off-by: Masahiro Yamada --- Changes in v2: None drivers/mmc/host/tmio_mmc.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) -- 2.7.4 diff --git a/drivers/mmc/host/tmio_mmc.c b/drivers/mmc/host/tmio_mmc.c index b031a77..e04c322 100644 --- a/drivers/mmc/host/tmio_mmc.c +++ b/drivers/mmc/host/tmio_mmc.c @@ -48,19 +48,27 @@ static void tmio_mmc_clk_stop(struct tmio_mmc_host *host) static void tmio_mmc_set_clock(struct tmio_mmc_host *host, unsigned int new_clock) { - u32 clk = 0, clock; + unsigned int clock, divisor; + u32 clk = 0; + int clk_sel; if (new_clock == 0) { tmio_mmc_clk_stop(host); return; } - clock = host->mmc->f_min; + divisor = host->pdata->hclk / new_clock; - for (clk = 0x80000080; new_clock >= (clock << 1); clk >>= 1) - clock <<= 1; + if (divisor <= 1) { + clk_sel = 1; + clk = 0; + } else { + clk_sel = 0; + /* bit7 set: 1/512, ... bit0 set:1/4, all bits clear: 1/2 */ + clk = roundup_pow_of_two(divisor) >> 2; + } - host->pdata->set_clk_div(host->pdev, (clk >> 22) & 1); + host->pdata->set_clk_div(host->pdev, clk_sel); sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, ~CLK_CTL_SCLKEN & sd_ctrl_read16(host, CTL_SD_CARD_CLK_CTL));