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 3030B3BB4A; Fri, 13 Feb 2026 08:17:03 +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=1770970624; cv=none; b=T/5yb1tdlYGcwNTAtV9KkOZMPciPOaUU7dZkab27jl+n1O81UTsIL/GRr1WNT5sKcpUL/m4YN5Jo99z6a+lG49ImiBrRDwuUNph0Bo02crcK5Pl7WxgTFVUIY6xMT39Y1MSEx86/DYX71VodfgHIL5gPpM8r5ipQn26lcYkp3+8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770970624; c=relaxed/simple; bh=hbYAQt6TNDZ/qXSwhJHkgExQTtHCoS7ggq1824ovTnU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=So0yKHIZuRSIRoDDT8NliUuClIz6GchdKEwe2TVTZDg1IplIunsPtWUGMdOwuccUqEIsAQDQ3KyjodINVaAF9XJOgoYyrjbK/UbTxHfaK/2hgaVLFNCZHQ0mBLYUklxpyT+fZaR304DCY2mgL45OpIWcitwyuhIui3V3UZiwwHA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=sz+4oPuw; 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="sz+4oPuw" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9CB68C116C6; Fri, 13 Feb 2026 08:17:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1770970623; bh=hbYAQt6TNDZ/qXSwhJHkgExQTtHCoS7ggq1824ovTnU=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=sz+4oPuwy6Y0e3rrzOZBPH52OtlvC18v6Q17Tg/0qckunMalGdoOMAKPS5BvhWe0t E4XmiXd7zeq3gP8n6EJbjnWlMIh/kcAmlTPfX1oViwtfCtJkPYHif3MKg87/BnLhmn H0lo1MtX65GWK640lVwPj32jkNsBZb1TkxlNoFuOgpIT5swr6mWpIZBgSc6aNR+YOU zNJ1WZJ5nLj/JBh7IzaM6ILk7wvcEfk+q3CvzLjGl8zbLmMndKlw3RAOBoTtlhCWsI flAX+O9Cxh9tBV18rzv2V8XYRTUvbPKPlBZU8lnpl1TiiZVMQaIh6L/nNjh/GuA3x0 kti5SGsXOxbmg== Message-ID: <2f68ee18-e9d9-4da6-900c-93a7663b3c9d@kernel.org> Date: Fri, 13 Feb 2026 09:16:58 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RFC v4 1/4] media: dt-bindings: Add Amlogic V4L2 video decoder To: Zhentao Guo , Mauro Carvalho Chehab , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Neil Armstrong , Kevin Hilman , Jerome Brunet , Martin Blumenstingl Cc: linux-media@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-amlogic@lists.infradead.org References: <20260213-b4-s4-vdec-upstream-v4-0-c7112d00d662@amlogic.com> <20260213-b4-s4-vdec-upstream-v4-1-c7112d00d662@amlogic.com> <75e55ceb-e6dd-47b5-a829-66f6fbb3e13e@amlogic.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 13/02/2026 09:02, Zhentao Guo wrote: > Hi Krzysztof, > > > 在 2026/2/13 15:35, Krzysztof Kozlowski 写道: >> [ EXTERNAL EMAIL ] >> >> On 13/02/2026 06:12, Zhentao Guo via B4 Relay wrote: >>> From: Zhentao Guo >>> >>> Describe the initial support for the V4L2 stateless video decoder >>> driver used with the Amlogic S4 (S805X2) platform. >>> >>> Signed-off-by: Zhentao Guo >>> --- >>> .../bindings/media/amlogic,s4-vcodec-dec.yaml | 96 ++++++++++++++++++++++ >>> 1 file changed, 96 insertions(+) >>> >>> diff --git a/Documentation/devicetree/bindings/media/amlogic,s4-vcodec-dec.yaml b/Documentation/devicetree/bindings/media/amlogic,s4-vcodec-dec.yaml >>> new file mode 100644 >>> index 000000000000..88780514d06c >>> --- /dev/null >>> +++ b/Documentation/devicetree/bindings/media/amlogic,s4-vcodec-dec.yaml >>> @@ -0,0 +1,96 @@ >>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) >>> +# Copyright (C) 2025 Amlogic, Inc. All rights reserved >>> +%YAML 1.2 >>> +--- >>> +$id:http://devicetree.org/schemas/media/amlogic,s4-vcodec-dec.yaml# >>> +$schema:http://devicetree.org/meta-schemas/core.yaml# >>> + >>> +title: Amlogic Video Decode Accelerator >>> + >>> +maintainers: >>> + - Zhentao Guo >>> + >>> +description: >>> + The Video Decoder Accelerator present on Amlogic SOCs. >>> + It supports stateless h264 decoding. >>> + >>> +properties: >>> + compatible: >>> + const: amlogic,s4-vcodec-dec >> Why do you repeat "dec" twice? codec means decoder, so what is the last >> "dec" about? > In fact, codec means encoder+decoder, and dec is short for decoder. Yes, that's what I meant, so why do you repeat decoder? >>> + >>> + reg: >>> + maxItems: 2 >>> + >>> + reg-names: >>> + items: >>> + - const: dos >>> + - const: dmc >>> + >>> + interrupts: >>> + maxItems: 3 >>> + >>> + clocks: >>> + maxItems: 3 >>> + >>> + clock-names: >>> + items: >>> + - const: vdec >>> + - const: clk_vdec_mux >>> + - const: clk_hevcf_mux >> Name them based on their role/name in this device. Why this device would >> care that it receives a mux? Not a div? or not a gate? > Ok, previously we overlooked this. We will improve it in the next version. >>> + >>> + power-domains: >>> + maxItems: 2 >>> + >>> + power-domain-names: >>> + items: >>> + - const: vdec >>> + - const: hevc >>> + >>> + resets: >>> + maxItems: 1 >>> + >>> + amlogic,canvas: >>> + description: should point to a canvas provider node >> Why? What for? >> >> What is canvas provider? > > The canvas provider is: drivers/soc/amlogic/meson-canvas.c What is this "canvas" device. > > In short, canvas is a hardware IP inside the Amlogic SoC. The decoder IP > needs to access DDR through canvas IP, so we need to reference the Why decoder cannot access DDR directly? Best regards, Krzysztof