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 00085D73E83 for ; Thu, 29 Jan 2026 17:46:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type: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=sbQkO/aU6GO1ByLXLbgZaMgMyf+e1d/FazyAtfU3Usc=; b=l5dkToiil8DadAeQYul/O20p3d CWr/N3jccWlwyhDGg5aUTraeM+2qpL8b+F4cIKeRDyuZWjGikIdl4iRykKLRrqtforyUQS2/qbHGz Z5P/90YoXIbVqnl6ZInNWSW497oQ3TvYFlB8h4acQV0WZcYJdx0ey3oEIUbiscZ6h50Qouor+p4Uo NX0vpZuMUKbHq7M3zQHviD73sjamAU5246gRXh+j9I4PAuBLZYMvUAp/0sAflq1yB0MQ7Y7zkloeY xQijPvNXfuYckIFuFGLiPhBtjEUgWEZMxGM0ukk6Jj/G02jx2PxMQjubsv4Jfwm7xnf4luXfq+CMK cn9THQ7w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vlW6H-00000000T77-1LvT; Thu, 29 Jan 2026 17:46:37 +0000 Received: from out-178.mta0.migadu.com ([91.218.175.178]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vlW6E-00000000T6k-0kaE for linux-arm-kernel@lists.infradead.org; Thu, 29 Jan 2026 17:46:35 +0000 Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1769708791; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=sbQkO/aU6GO1ByLXLbgZaMgMyf+e1d/FazyAtfU3Usc=; b=sY+tz50AYFXBsC6bljckZOdSlmfyEXAcftS8CKgQCNTOjImPluZCAXtLfgcvmvE4s1lvEM +sN8/m4q5L5ohdcFHV5t5g0m/xQ3gvgfXinC3WU3hRdmh6ZyskdGACWzD94JEcOFOPjjnL VyfKUFzpi02PxRmAbM2lG1zaUE+TMiU= Date: Thu, 29 Jan 2026 12:46:27 -0500 MIME-Version: 1.0 Subject: Re: [PATCH 2/2] ASoC: xilinx: xlnx_i2s: Discover parameters from registers To: Mark Brown Cc: Vincenzo Frascino , Liam Girdwood , linux-sound@vger.kernel.org, Jaroslav Kysela , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Michal Simek , Takashi Iwai References: <20260129172315.3871602-1-sean.anderson@linux.dev> <20260129172315.3871602-3-sean.anderson@linux.dev> <700e4e67-a2ed-4b37-a00b-303bbc5ee6cd@sirena.org.uk> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Sean Anderson In-Reply-To: <700e4e67-a2ed-4b37-a00b-303bbc5ee6cd@sirena.org.uk> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260129_094634_532545_66A8068C X-CRM114-Status: GOOD ( 12.73 ) 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 1/29/26 12:27, Mark Brown wrote: > On Thu, Jan 29, 2026 at 12:23:15PM -0500, Sean Anderson wrote: > >> - ret = of_property_read_u32(node, "xlnx,num-channels", &drv_data->channels); > >> - ret = of_property_read_u32(node, "xlnx,dwidth", &drv_data->data_width); > > Given that the properties already exist it seems wise to continue to > parse them if available and prefer them over what we read from the > hardware, it would not shock me to discover that hardware exists where > the registers are inaccurate or need overriding due to bugs. I would be surprised if such hardware exists. These properties are automatically generated by Xilinx's tools based on the HDL core's properties. This has a few consequences: - They always exactly match the hardware unless someone has gone in and modified them. I think this is unlikely in this case because they directly reflect parameters that should not need to be adjusted. - Driver authors tend to use them even when there are hardware registers available with the same information, as Xilinx has not always been consistent in adding such registers. I am not aware of any errata regarding incorrect generation of properties for this device or cases where the number of channels or bit depth was incorrect. --Sean