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[209.132.180.67]) by mx.google.com with ESMTP id q10-v6si5247090pgk.392.2018.09.28.10.29.15; Fri, 28 Sep 2018 10:29:30 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729568AbeI1Xxv (ORCPT + 99 others); Fri, 28 Sep 2018 19:53:51 -0400 Received: from mailgw01.mediatek.com ([210.61.82.183]:28251 "EHLO mailgw01.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726934AbeI1Xxv (ORCPT ); Fri, 28 Sep 2018 19:53:51 -0400 X-UUID: 291f019845d843f883bccc5bb87c9336-20180929 Received: from mtkexhb02.mediatek.inc [(172.21.101.103)] by mailgw01.mediatek.com (envelope-from ) (mhqrelay.mediatek.com ESMTP with TLS) with ESMTP id 949012611; Sat, 29 Sep 2018 01:28:59 +0800 Received: from mtkcas08.mediatek.inc (172.21.101.126) by mtkmbs08n2.mediatek.inc (172.21.101.56) with Microsoft SMTP Server (TLS) id 15.0.1395.4; Sat, 29 Sep 2018 01:28:56 +0800 Received: from [172.21.77.33] (172.21.77.33) by mtkcas08.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1395.4 via Frontend Transport; Sat, 29 Sep 2018 01:28:56 +0800 Message-ID: <1538155736.30348.85.camel@mtkswgap22> Subject: Re: [PATCH 2/2] mmc: mediatek: add bus_clk control From: Sean Wang To: Chaotian Jing CC: Ulf Hansson , Rob Herring , Mark Rutland , Matthias Brugger , Ryder Lee , Wolfram Sang , , , , , , Date: Sat, 29 Sep 2018 01:28:56 +0800 In-Reply-To: <1538134855-11198-3-git-send-email-chaotian.jing@mediatek.com> References: <1538134855-11198-1-git-send-email-chaotian.jing@mediatek.com> <1538134855-11198-3-git-send-email-chaotian.jing@mediatek.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 7bit MIME-Version: 1.0 X-TM-SNTS-SMTP: 9D4A873FA4222DAB7E281D0A14AC35E6A93D874B5F3C00A84CB068A70E33D88F2000:8 X-MTK: N Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Fri, 2018-09-28 at 19:40 +0800, Chaotian Jing wrote: > when gate MSDC0_HCLK, access register will hang, even the MSDC driver > will never accessing register after HCLK was gated, but for safety, need > gate the bus_clk(which used to access register) too. > > Signed-off-by: Chaotian Jing > --- > drivers/mmc/host/mtk-sd.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/drivers/mmc/host/mtk-sd.c b/drivers/mmc/host/mtk-sd.c > index 0484138..1c1c967 100644 > --- a/drivers/mmc/host/mtk-sd.c > +++ b/drivers/mmc/host/mtk-sd.c > @@ -387,6 +387,7 @@ struct msdc_host { > > struct clk *src_clk; /* msdc source clock */ > struct clk *h_clk; /* msdc h_clk */ > + struct clk *bus_clk; /* bus clock which used to access register */ > struct clk *src_clk_cg; /* msdc source clock control gate */ > u32 mclk; /* mmc subsystem clock frequency */ > u32 src_clk_freq; /* source clock frequency */ > @@ -660,12 +661,14 @@ static void msdc_gate_clock(struct msdc_host *host) > { > clk_disable_unprepare(host->src_clk_cg); > clk_disable_unprepare(host->src_clk); > + clk_disable_unprepare(host->bus_clk); > clk_disable_unprepare(host->h_clk); > } > > static void msdc_ungate_clock(struct msdc_host *host) > { > clk_prepare_enable(host->h_clk); > + clk_prepare_enable(host->bus_clk); > clk_prepare_enable(host->src_clk); > clk_prepare_enable(host->src_clk_cg); > while (!(readl(host->base + MSDC_CFG) & MSDC_CFG_CKSTB)) > @@ -1900,6 +1903,9 @@ static int msdc_drv_probe(struct platform_device *pdev) > goto host_free; > } > > + host->bus_clk = devm_clk_get(&pdev->dev, "bus_clk"); > + if (IS_ERR(host->bus_clk)) > + host->bus_clk = NULL; The implementation would cause all SoCs to treat the bus_clk as the optional. It seems you should add a flag to see what SoC requires the bus_clk to successfully access the related registers. > /*source clock control gate is optional clock*/ > host->src_clk_cg = devm_clk_get(&pdev->dev, "source_cg"); > if (IS_ERR(host->src_clk_cg))