From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0043CC43381 for ; Fri, 1 Mar 2019 16:51:28 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C6C7C20818 for ; Fri, 1 Mar 2019 16:51:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="ghPhbY7M" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C6C7C20818 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender:Content-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=1QuSNeg2RS+FxErfvL4i4WlYnw3ptWjA+s0dR6t74Ik=; b=ghPhbY7MqNhZy8KNvmo95AjnL mZxgt6E1vrG7wSJHBxE8rAsUHO6RnZ3TzUnaQgtgiFSTMmwZJ7c92ahkt2/2NDhphHg6pkJcMVXJ7 0LEVyhKndrHYKLZeOOvH6xjveFyx/ZkaVWNx15LJ+Sm2tXjy/0vVs8yDiLDQsYw36EgLtAdwRHwUL 02a4Un0AfLS265ze1M1lDCMEsyeGxh2jAfytQdHLFtfr7CH/zal1cludSapfgY3iA0NjFRQl8yw1O Sv0aKioRqxbOLcUyO6X3s0CItdO+g3gIH0nFuEi4nORYmeZxYSpwdC1ZZ0k9ekrr2ilNhtLVM5bk4 uJBwk9JSQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gzlNZ-0001p8-Lj; Fri, 01 Mar 2019 16:51:21 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gzlNV-0001oe-Vg; Fri, 01 Mar 2019 16:51:19 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 4D39680D; Fri, 1 Mar 2019 08:51:16 -0800 (PST) Received: from [10.1.196.75] (e110467-lin.cambridge.arm.com [10.1.196.75]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0DAFA3F575; Fri, 1 Mar 2019 08:51:12 -0800 (PST) Subject: Re: [PATCH 1/3] phy: rockchip-emmc: Allow to set drive impedance via DTS. To: Christoph Muellner , robh+dt@kernel.org, mark.rutland@arm.com, heiko@sntech.de, shawn.lin@rock-chips.com References: <20190301153348.29870-1-christoph.muellner@theobroma-systems.com> From: Robin Murphy Message-ID: <1347b956-5682-1f86-b38c-7768bb9ffd23@arm.com> Date: Fri, 1 Mar 2019 16:51:11 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <20190301153348.29870-1-christoph.muellner@theobroma-systems.com> Content-Language: en-GB X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190301_085118_035381_BCF0E3FB X-CRM114-Status: GOOD ( 25.84 ) 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: devicetree@vger.kernel.org, Matthias Brugger , Emil Renner Berthing , Viresh Kumar , Randy Li , linux-kernel@vger.kernel.org, Vicente Bergas , Douglas Anderson , linux-rockchip@lists.infradead.org, Tony Xie , Klaus Goger , Enric Balletbo i Serra , Philipp Tomsich , Kishon Vijay Abraham I , Ezequiel Garcia , linux-arm-kernel@lists.infradead.org Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 01/03/2019 15:33, Christoph Muellner wrote: > The rockchip-emmc PHY can be configured with different > drive impedance values. Currenlty a value of 50 Ohm is > hard coded into the driver. > > This patch introduces the DTS property 'drive-impedance-ohm' > for the rockchip-emmc phy node, which uses the value from the DTS > to setup the drive impedance accordingly. > > Signed-off-by: Christoph Muellner > Signed-off-by: Philipp Tomsich > --- > drivers/phy/rockchip/phy-rockchip-emmc.c | 38 ++++++++++++++++++++++++++++++-- > 1 file changed, 36 insertions(+), 2 deletions(-) > > diff --git a/drivers/phy/rockchip/phy-rockchip-emmc.c b/drivers/phy/rockchip/phy-rockchip-emmc.c > index 19bf84f0bc67..5413fa73dd45 100644 > --- a/drivers/phy/rockchip/phy-rockchip-emmc.c > +++ b/drivers/phy/rockchip/phy-rockchip-emmc.c > @@ -87,6 +87,7 @@ struct rockchip_emmc_phy { > unsigned int reg_offset; > struct regmap *reg_base; > struct clk *emmcclk; > + unsigned int drive_impedance; > }; > > static int rockchip_emmc_phy_power(struct phy *phy, bool on_off) > @@ -281,10 +282,10 @@ static int rockchip_emmc_phy_power_on(struct phy *phy) > { > struct rockchip_emmc_phy *rk_phy = phy_get_drvdata(phy); > > - /* Drive impedance: 50 Ohm */ > + /* Drive impedance: from DTS */ > regmap_write(rk_phy->reg_base, > rk_phy->reg_offset + GRF_EMMCPHY_CON6, > - HIWORD_UPDATE(PHYCTRL_DR_50OHM, > + HIWORD_UPDATE(rk_phy->drive_impedance, > PHYCTRL_DR_MASK, > PHYCTRL_DR_SHIFT)); > > @@ -314,6 +315,28 @@ static const struct phy_ops ops = { > .owner = THIS_MODULE, > }; > > +static u32 convert_drive_impedance_ohm(struct platform_device *pdev, u32 dr_ohm) > +{ > + switch (dr_ohm) { > + case 100: > + return PHYCTRL_DR_100OHM; > + case 66: > + return PHYCTRL_DR_66OHM; > + case 50: > + return PHYCTRL_DR_50OHM; > + case 40: > + return PHYCTRL_DR_40OHM; > + case 33: > + return PHYCTRL_DR_33OHM; > + } > + > + dev_warn(&pdev->dev, > + "Invalid value %u for drive-impedance-ohm. " > + "Falling back to 50 Ohm.\n", > + dr_ohm); > + return PHYCTRL_DR_50OHM; > +} > + > static int rockchip_emmc_phy_probe(struct platform_device *pdev) > { > struct device *dev = &pdev->dev; > @@ -322,6 +345,7 @@ static int rockchip_emmc_phy_probe(struct platform_device *pdev) > struct phy_provider *phy_provider; > struct regmap *grf; > unsigned int reg_offset; > + u32 val; > > if (!dev->parent || !dev->parent->of_node) > return -ENODEV; > @@ -345,6 +369,16 @@ static int rockchip_emmc_phy_probe(struct platform_device *pdev) > rk_phy->reg_offset = reg_offset; > rk_phy->reg_base = grf; > > + if (of_property_read_u32(dev->of_node, "drive-impedance-ohm", &val)) { > + dev_info(dev, > + "Missing drive-impedance-ohm property in node %s " > + "Falling back to 50 Ohm.\n", > + dev->of_node->name); I think we're aiming to use %pOF for node names now, but here it looks redundant anyway - dev_info() will already show the device name, which for an of_platform device is the same thing. > + rk_phy->drive_impedance = PHYCTRL_DR_50OHM; > + } else { > + rk_phy->drive_impedance = convert_drive_impedance_ohm(pdev, val); > + } FWIW, if you initialise val to the default (i.e. 50) then you could get rid of the "else" case and just do the conversion unconditionally. That's a fairly common idiom for reading optional properties. Robin. > + > generic_phy = devm_phy_create(dev, dev->of_node, &ops); > if (IS_ERR(generic_phy)) { > dev_err(dev, "failed to create PHY\n"); > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel