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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id C3026C48297 for ; Mon, 12 Feb 2024 17:32:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:From:References:CC:To:Subject: MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=8ILoAJGLoui5zpsukwJzdZ2WmcZ1KYpPRuSouBof2p8=; b=nPxOb+mfhf1a2q pRHcpGePsElGSRmUT6y01TaWBn0998ISuDwfSBqikcWhe4Ki/WHJ+A8nq58yMjSOl5K2fjIHyjgJD WJ2aK3i84UOvPK05TdhHFnrROYOqUYgi0STxsvPe6eO0AVFhYzEzmhmOYXyOAy1+OVZxF+w4Rss7s tBabWPz2jmrj7qzV0PHMNO4r/NpYHxTbHjYc4jBiWveXZFxQD82dGtjbab53YnH8HKpyk6NUdi/OJ GIZ6Ah7tXg0l7VVeBX0wgaUl1Cx0Q0Q1Bo6AejA0nlWsqfqle+gbte+05fcMbMcHE5CykY4zHmtJN A4UVMGo41Y6Bj7lLWSKg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rZa9s-00000006Rf2-0HWd; Mon, 12 Feb 2024 17:31:56 +0000 Received: from lelv0143.ext.ti.com ([198.47.23.248]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1rZa9o-00000006Rbm-2moJ for linux-arm-kernel@lists.infradead.org; Mon, 12 Feb 2024 17:31:54 +0000 Received: from lelv0265.itg.ti.com ([10.180.67.224]) by lelv0143.ext.ti.com (8.15.2/8.15.2) with ESMTP id 41CHVb0B072153; Mon, 12 Feb 2024 11:31:37 -0600 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1707759097; bh=qFz9E77b4ViF9Ae4NJ5AyukglGb22Hx5MYZrPMtvh8U=; h=Date:Subject:To:CC:References:From:In-Reply-To; b=vY9es+EJTElRhv974rrJFZCjZneMsLhdE0IM/fc1iNCLJG9qz97PTFf6R8EEQZsCB hG5l1CtT1c8LQRGEgrCKKOiTW5yDKe/cL/dZxFAsaV+nJk0ik5hl2dFYcpfbX690W+ x+kxxMBJQLYJcp/VWNtkVZ8PYHZ86Vg8aQy4rA+4= Received: from DLEE106.ent.ti.com (dlee106.ent.ti.com [157.170.170.36]) by lelv0265.itg.ti.com (8.15.2/8.15.2) with ESMTPS id 41CHVb9r021585 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Mon, 12 Feb 2024 11:31:37 -0600 Received: from DLEE100.ent.ti.com (157.170.170.30) by DLEE106.ent.ti.com (157.170.170.36) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2507.23; Mon, 12 Feb 2024 11:31:36 -0600 Received: from lelvsmtp5.itg.ti.com (10.180.75.250) by DLEE100.ent.ti.com (157.170.170.30) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2507.23 via Frontend Transport; Mon, 12 Feb 2024 11:31:36 -0600 Received: from [128.247.81.105] (judy-hp.dhcp.ti.com [128.247.81.105]) by lelvsmtp5.itg.ti.com (8.15.2/8.15.2) with ESMTP id 41CHVagU066580; Mon, 12 Feb 2024 11:31:36 -0600 Message-ID: <22af7436-8833-4049-bdbb-f79bb3314ee8@ti.com> Date: Mon, 12 Feb 2024 11:31:36 -0600 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v1 0/9] Fix MMC properties on Sitara devices Content-Language: en-US To: Francesco Dolcini CC: Rob Herring , Krzysztof Kozlowski , Conor Dooley , Nishanth Menon , Vignesh Raghavendra , Tero Kristo , , , References: <20240207225526.3953230-1-jm@ti.com> <20240211154411.GA3360@francesco-nb> From: Judith Mendez In-Reply-To: <20240211154411.GA3360@francesco-nb> X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240212_093152_842503_9736B625 X-CRM114-Status: GOOD ( 20.67 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Francesco, On 2/11/24 9:44 AM, Francesco Dolcini wrote: > Hello Judith and TI folks, > > On Wed, Feb 07, 2024 at 04:55:17PM -0600, Judith Mendez wrote: >> This patch series aims to add or fix MMC properties: >> OTAPDLY/ITAPDLY. >> >> The DLL properties ti,trm-icp and ti,driver-strength-ohm >> should also be updated since only AM64x and AM62p devices >> have a DLL to enable, so remove these properties when not >> applicable. > > Do you have any reference regarding this change? TI reference manual or > anything like that? I believe there is no specific documentation that states outright that these device tree properties are not applicable for devices like AM62x. There are a few hints in the device datasheet and TRM, if the MMC PHY has a DLL to enable, DLL properties should show in both docs. Also, you can read the MMC bindings doc description: https://github.com/torvalds/linux/blob/master/Documentation/devicetree /bindings/mmc/sdhci-am654.yaml#L179 > > No change needed in sdhci_am654.c? It seems that `drv_strength` is written > to some register unconditionally, is it ok to do so? Actually, we only write this value to the register if there is a DLL to enable. If we have this property in device tree for devices like AM62x and AM62ax, this property is ignored in the driver. So I am removing this property from device tree as part of the effort to clean up MMC nodes in device tree. > > Do this change implies that there is no way to configure the drive > strength on such SoCs and MMC/SD trace impedance must be the nominal > 50ohm? We do not support changing drive strength for these devices. My understanding is that the drive strength should default to about 40 ohms, which should be good enough for any eMMC operating mode. ~ Judith > > Thanks, > Francesco > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel