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 5CBC714AD2D; Mon, 3 Mar 2025 07:31:31 +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=1740987092; cv=none; b=ky5TbUiFvALlMlTaKigdQDLDUk1W1AH8b/MvXagBb0Xk5b5TIUiiItID+KCOXnGO/FZcObnLbedkgXfb+ftAmS7DSkS22QklUVqV4BV6nIGoQvPJgXEgBoZ2vgEJPVqmaIh7lFxE6VDHu+fAPHnBR0ZpQyLX3HUQtBJovb9FZlI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740987092; c=relaxed/simple; bh=Rp+ML2bibpqktoLUGR92Bz7M855WOGJIx85KWI6GPlY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Qs/rqmr1PCo3H0sUZ9KVUfarUOj+NsP1wfjmQLXG0WIKQaeK6qK+/w0+UQD3te/wCKDFiZbRc6rN+Yg4pTVy0sssnopchUbeRiJxphCiNlC7pclhI9TvEdcC++q8C0edegJVN+a8VOs4y6a2Ba5yl/IkOPBqx//O5BB/9CHblbQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=HTzEGiFf; 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="HTzEGiFf" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AA799C4CED6; Mon, 3 Mar 2025 07:31:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1740987091; bh=Rp+ML2bibpqktoLUGR92Bz7M855WOGJIx85KWI6GPlY=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=HTzEGiFfHLV4w3wmTYdgM1MCufXU4oIQ7PNRV0iGYfH7O1AlC9I9jG8mRefk8kGMk hHaX3prwYZyBKkE9OkYkGGbfe4+xwGnXulJ7Tn+Yqhbes5R4tmKYP75jte80SDKIrX ORktdyG6hGNsc+7RzDE68WQt/m9XnfY8ftWGpyWBeQ2r/NSrTW1qY8x8VokwBvGAtf KwjwSt0LjcHRMPqtg1L3JUujWt3sRkfsY3yO5yyHWKsDWKS3aIcwN+ecSJXmqz/oNX IH1cwiQLFaJoLuhdLdx/btKuJqw+tg0teun2eDbRAcaZAqjQ2JrgstmwN5S8kQPsss 7blHovP1SNM+A== Message-ID: <3d729159-4d13-4a61-88c7-3be992b23728@kernel.org> Date: Mon, 3 Mar 2025 08:31:24 +0100 Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/2] media: dt-bindings: Add dt bindings for m2m-deinterlace device To: Matthew Majewski Cc: Mauro Carvalho Chehab , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Hans Verkuil , "Dr. David Alan Gilbert" , Neil Armstrong , Uwe Kleine-Konig , Andrzej Pietrasiewicz , devicetree@vger.kernel.org, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org References: <20250214231759.119481-1-mattwmajewski@gmail.com> <20250214231759.119481-2-mattwmajewski@gmail.com> <20250218-eggplant-skylark-of-swiftness-dcf6ba@krzk-bin> <69cb2e95c291f17cff42b45e7c871f30a85c060d.camel@gmail.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 26/02/2025 23:41, Matthew Majewski wrote: > Hi Krzysztof, > > On Tue, 2025-02-18 at 09:30 +0100, Krzysztof Kozlowski wrote: >> On Fri, Feb 14, 2025 at 06:17:58PM -0500, Matthew Majewski wrote: >>> Create a new yaml schema file to describe the device tree bindings >>> for >>> generic m2m-deinterlace device. >>> >>> This device is supported on any hardware that provides a MEM_TO_MEM >> >> Which device? I don't see here any device name/model. > > By "device" I am referring to the m2m-deinterlace device, which I > explained is a quasi-virtual device. If this is confusing wording I can > change. > >> I asked to provide here some examples of devices. > > As I wrote, supported devices/hardware is anything that provides a > MEM_TO_MEM capable dma-controller with interleaved transfer support. I > did not list specific devices because the bindings are supposed to be > generic, as they are not describing actual silicon. But if you want me I already told you that no. Bindings are not supposed to be generic. >From where did you get such information? > to list some devices which provide a compatible dma-controller, here > are devices I found in the current mainline kernel: > > - TI OMAP Soc Family > - TI Davinci Soc Family > - TI Keystone Processor Family > - IMX27 Processor and variants > - Several Microchip Processors (sama5, sam9x7, sam9x60) That's too generic - you just listed SoCs, which consist of dozen or hundred of devices. Which hardware piece is here? Maybe this is not for a real device, but then this should be marked clearly. > > As I mentioned in my original email, I have personally tested on a > BeagleBone Black with an AM335X OMAP processor. There are likely many > more devices with compatible dma-controllers that could be supported > with additional dmaengine driver support. > > >>> capable dma channel with interleaved trasfer support. Device tree >>> bindings are for providing appropriate dma channel to device. >> >> Don't describe what DT is, but the hardware. >> > > Ok, will remove reference to DT. > >>> +description: |- >>> +  A generic memory2memory device for deinterlacing video using >>> dmaengine. It can >>> +  convert between interlaced buffer formats and can convert >>> interlaced to >>> +  progressive using a simple line-doubling algorithm. This device >>> can be used on >>> +  any hardware that provides a MEM_TO_MEM capable dma controller >>> that supports >>> +  interleaved transfers. >> >> And how do you program that device to deinterlace? How do you signal >> end >> of frame/data when writing to the memory? >> >> It still looks all this is for driver :/ >> > > All of the deinterlacing is handled by the dma channel. To simplify a > bit, m2m-deinterlace basically just translates video format information > into appropriate interleaved dma transfers. Everything else (and > everything hardware specific) is handled by the dma engine, such as > initiation and signaling completion of transfers. So the device is the dma controller and maybe all this should be folded into that controller bindings. > > I think an appropriate analogy for m2m-deinterlace would be spi-gpio. > Since spi-gpio leverages gpio for bitbanging the spi protocol, the > bindings do not need to describe any clocks, spi-controller registers, Sure, SPI GPIO is Linux driver, not a device and I am asking about it all the time. > etc. All of the hardware specific components are abstracted away by the > gpio controller. But the spi-gpio bindings still exist to specify which > gpios are used. Best regards, Krzysztof