From patchwork Mon Sep 18 06:39:22 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wenyou.Yang@microchip.com X-Patchwork-Id: 9955547 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 01FD860568 for ; Mon, 18 Sep 2017 06:43:00 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E558C28AFF for ; Mon, 18 Sep 2017 06:42:59 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id DA66928B6A; Mon, 18 Sep 2017 06:42:59 +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=-4.2 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,RCVD_IN_DNSWL_MED autolearn=unavailable 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 690A428B66 for ; Mon, 18 Sep 2017 06:42:59 +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:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version: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=afqpD+RWh1szCjy7ra0x2tWevI1z95+lUtDJwFx6ZQs=; b=cQ2oxcK6qhN8Ef txPGbjALObLGoj9XG7E0V+37AmRkCYfQVBQcUeH9yv84MpdewkOR0ztmcmwqVJJW2xofDPAezj6br blRa9q3oEXEqrfx3PkKgOUWhvCJOEuaJ05AzW4LOn5z5Vcixn4RG8K2lR9f66qn6ZcupxdMVQuEC6 j/XRrcV/FrKIPL3AnpIrGUjwSsEA29710vr2Rxbn+FLzJsiX+SIhqp+g3cjQLIEHtX/kRqiSQ2UC8 vW08LbNh+JkZQTkb/SgOAw8S16bh0lSa/t52piSKnaPsoMA1WERtMHZ+3hi+vzAaRhr9xORVXW5jg ABnuBCRDKp4VYxjUTcOA==; 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 1dtple-00068i-UM; Mon, 18 Sep 2017 06:42:54 +0000 Received: from nasmtp01.atmel.com ([192.199.1.246] helo=DVREDG02.corp.atmel.com) by bombadil.infradead.org with esmtps (Exim 4.87 #1 (Red Hat Linux)) id 1dtpl2-0005bA-Ta for linux-arm-kernel@lists.infradead.org; Mon, 18 Sep 2017 06:42:52 +0000 Received: from apsmtp01.atmel.com (10.168.254.31) by DVREDG02.corp.atmel.com (10.42.103.31) with Microsoft SMTP Server (TLS) id 14.3.235.1; Mon, 18 Sep 2017 00:41:49 -0600 Received: from shaarm01.corp.atmel.com (10.168.254.13) by apsmtp01.atmel.com (10.168.254.31) with Microsoft SMTP Server id 14.3.235.1; Mon, 18 Sep 2017 14:46:24 +0800 From: Wenyou Yang To: Mauro Carvalho Chehab Subject: [PATCH v2 2/5] media: atmel-isc: Add prepare and unprepare ops Date: Mon, 18 Sep 2017 14:39:22 +0800 Message-ID: <20170918063925.6372-3-wenyou.yang@microchip.com> X-Mailer: git-send-email 2.13.0 In-Reply-To: <20170918063925.6372-1-wenyou.yang@microchip.com> References: <20170918063925.6372-1-wenyou.yang@microchip.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20170917_234222_911375_9020B769 X-CRM114-Status: UNSURE ( 9.60 ) X-CRM114-Notice: Please train this message. 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: Wenyou Yang , Jonathan Corbet , linux-kernel@vger.kernel.org, Hans Verkuil , Sakari Ailus , linux-arm-kernel@lists.infradead.org, Linux Media Mailing List 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 A software write operation to the ISC_CLKEN or ISC_CLKDIS register requires double clock domain synchronization and is not permitted when the ISC_SR.SIP is asserted. So add the .prepare and .unprepare ops to make sure the ISC_CLKSR.SIP is unasserted before the write operation to the ISC_CLKEN or ISC_CLKDIS register. Signed-off-by: Wenyou Yang --- Changes in v2: None drivers/media/platform/atmel/atmel-isc-regs.h | 1 + drivers/media/platform/atmel/atmel-isc.c | 30 +++++++++++++++++++++++++++ 2 files changed, 31 insertions(+) diff --git a/drivers/media/platform/atmel/atmel-isc-regs.h b/drivers/media/platform/atmel/atmel-isc-regs.h index 6936ac467609..93e58fcf1d5f 100644 --- a/drivers/media/platform/atmel/atmel-isc-regs.h +++ b/drivers/media/platform/atmel/atmel-isc-regs.h @@ -42,6 +42,7 @@ /* ISC Clock Status Register */ #define ISC_CLKSR 0x00000020 +#define ISC_CLKSR_SIP BIT(31) #define ISC_CLK(n) BIT(n) diff --git a/drivers/media/platform/atmel/atmel-isc.c b/drivers/media/platform/atmel/atmel-isc.c index 78114193af4c..8b9c1cafa348 100644 --- a/drivers/media/platform/atmel/atmel-isc.c +++ b/drivers/media/platform/atmel/atmel-isc.c @@ -308,6 +308,34 @@ module_param(sensor_preferred, uint, 0644); MODULE_PARM_DESC(sensor_preferred, "Sensor is preferred to output the specified format (1-on 0-off), default 1"); +static int isc_wait_clk_stable(struct clk_hw *hw) +{ + struct isc_clk *isc_clk = to_isc_clk(hw); + struct regmap *regmap = isc_clk->regmap; + unsigned long timeout = jiffies + usecs_to_jiffies(1000); + unsigned int status; + + while (time_before(jiffies, timeout)) { + regmap_read(regmap, ISC_CLKSR, &status); + if (!(status & ISC_CLKSR_SIP)) + return 0; + + usleep_range(10, 250); + } + + return -ETIMEDOUT; +} + +static int isc_clk_prepare(struct clk_hw *hw) +{ + return isc_wait_clk_stable(hw); +} + +static void isc_clk_unprepare(struct clk_hw *hw) +{ + isc_wait_clk_stable(hw); +} + static int isc_clk_enable(struct clk_hw *hw) { struct isc_clk *isc_clk = to_isc_clk(hw); @@ -459,6 +487,8 @@ static int isc_clk_set_rate(struct clk_hw *hw, } static const struct clk_ops isc_clk_ops = { + .prepare = isc_clk_prepare, + .unprepare = isc_clk_unprepare, .enable = isc_clk_enable, .disable = isc_clk_disable, .is_enabled = isc_clk_is_enabled,