From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 79B35225A47; Wed, 2 Jul 2025 20:38:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751488687; cv=none; b=NFVX2mMPz7HrSJmB0abMG5fbE+7FTLPDeLJVjugSxSYFWSV1ZbeK9cm2EumyeB3xMMdkoHiQDvdrCUkXnW654to19WCX20PjyCLSlLdtLej2lCyEeGodipq39gUZS5ZQdXPBFQ3hIq0rwjwitGUI3ovLbmm3NY1k++1va+yz1ug= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751488687; c=relaxed/simple; bh=dDCS6QVJ7nXRWlnC2SiSC9vvqcF5+4EB5/e+hxz2kYg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=UI8685KqAWZu7vct0Pzs+IgSVyJfyFeMVkaebg3XJ4xmXdAy0XFriTHzWimyf2ATLcfYaJr785djJ4bJFMOYYFaWKjGXgUq2xyYjig6hgzD4mHtXJnGR6O7Zka8OaG4hcBXzObJSAeQcrAvW3sg5MKZ+Nu3p1fNKHN9uTTrstmE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=vPRpVWdn; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="vPRpVWdn" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BF21EC4CEE7; Wed, 2 Jul 2025 20:38:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1751488687; bh=dDCS6QVJ7nXRWlnC2SiSC9vvqcF5+4EB5/e+hxz2kYg=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=vPRpVWdnh+OJAAA7arYY7PnTcK2jpNELhtnvDh4laCUI4hYVphhNSPs460L2IVWTr 1jpr5XgjEgv88LJM91FV1cNYfzB7YLuH9t4SdJC4DNuy9RqwgcjL+99vF3iuJ1SctZ ARHOTjY1hY8ZUrKMa/jH/4mi5bmpe0EB6KOC/Y7QKXXjfTaQTMI7TcjZlR4uOWwzpO npAM2tFfXbRoGuWi1e2mt8hxCh3uiDlhHKU8fHBgR5DetbenJmcGQl54fPFsVTQ3Oh ieCiVM47209l1++MMj/p6W+sbLAwaZixwCFKlfFnwbk9kM15X/w6gTj592919C4Z9u PBAsrRUs6476w== Message-ID: <43f19fbc-838b-431e-9d02-ecacf5f43731@kernel.org> Date: Wed, 2 Jul 2025 22:38:00 +0200 Precedence: bulk X-Mailing-List: spacemit@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/8] dt-bindings: dma: marvell,mmp-dma: Add SpacemiT K1 PDMA support To: Guodong Xu Cc: Vinod Koul , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Yixun Lan , =?UTF-8?Q?Duje_Mihanovi=C4=87?= , Philipp Zabel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Alex Elder , Vivian Wang , dmaengine@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, spacemit@lists.linux.dev References: <20250701-working_dma_0701_v2-v2-0-ab6ee9171d26@riscstar.com> <20250701-working_dma_0701_v2-v2-1-ab6ee9171d26@riscstar.com> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 8bit On 01/07/2025 11:52, Guodong Xu wrote: > Hi, Krzysztof > > On Tue, Jul 1, 2025 at 3:35 PM Krzysztof Kozlowski wrote: >> >> On 01/07/2025 07:36, Guodong Xu wrote: >>> Add "spacemit,k1-pdma" compatible string to support SpacemiT K1 PDMA >>> controller. This variant requires: >> >> Why is this marvell? This should be explained here, it's really unexpected. >> > > SpacemiT K1 SoC uses the same DMA controller as Marvell MMP. They share most > of the registers (and address offsets) and only enhanced in addressing space > capability (from 32bit to 64bit). I hope you got the last comment... > > Also, spacemit,k1-pdma and marvell,pdma-1.0 use the same driver (mmp_pdma.c), > that's the reason why I chose keeping them in the same binding file. That's moderate reason. I explained here further - don't grow old bindings with completely new devices, because you keep growing old, poorer patterns. You have a new device, you can make it right. ... >>> + properties: >>> + compatible: >>> + contains: >>> + const: spacemit,k1-pdma >>> + then: >>> + required: >>> + - clocks >>> + - resets >>> + else: >>> + properties: >>> + clocks: false >>> + resets: false >>> + - if: >>> + properties: >>> + compatible: >>> + contains: >>> + enum: >>> + - marvell,pdma-1.0 >>> + - spacemit,k1-pdma >>> + then: >>> + properties: >>> + '#dma-cells': >>> + const: 2 >>> + description: >>> + The first cell contains the DMA request number for the peripheral >>> + device. The second cell is currently unused but must be present for >>> + backward compatibility. >>> + else: >>> + properties: >>> + '#dma-cells': >>> + const: 1 >>> + description: >>> + The cell contains the DMA request number for the peripheral device. >> >> >> It's getting complicated. I suggest to make your own schema. Then you >> would also switch to preferred 'sram' property instead of that legacy >> 'asram'. >> >> Really, ancient schemas should not be grown for new, completely > > The reason that they share the same device driver may not be strong enough > compared to what you said here. If DMA maintainer(s) reject complexity in driver, then it is fine. But till that happens, you should rather come with a clean new binding and don't grow legacy. Best regards, Krzysztof