From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.marcansoft.com (marcansoft.com [212.63.210.85]) (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 8D1C31DB361 for ; Tue, 26 Nov 2024 18:24:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=212.63.210.85 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732645465; cv=none; b=d2GO99Yitl322ppeJpAMWIEPGcubLWWx6d15izFFb6UgRR/Dq42Zd/mYEiW/XBldmhaz3JIvWLUG2trm3tipALn6Bce3LmGO/OVZBUylKtSjMoPx4Cau3PpTOExonHmuz1zDDsWjRkrR4OEQzQq/u/tntOFXYM8wOT4Xs7t+5gc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732645465; c=relaxed/simple; bh=hF79OJOTF3Zhn8zXCNMfZBZW+wmNbw9AS1gO9o5YyZY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=S5COozzgMNE46qTIelQcpG19CX/dLyn8c0dj7PVSfb+poWDyBM4r/ZupmfnjKRZ7eaIgNbgGSgr4daotMsupY4XFUe3Zyl30//W0aVyevfmAyWLw81+CBpk17xHi/uNbb3EaCud6iahHzW1QQDbj0ggAsxHL77RPi1oaaY4ayRU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=marcan.st; spf=pass smtp.mailfrom=marcan.st; dkim=pass (2048-bit key) header.d=marcan.st header.i=@marcan.st header.b=DrCj3ZNg; arc=none smtp.client-ip=212.63.210.85 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=marcan.st Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=marcan.st Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=marcan.st header.i=@marcan.st header.b="DrCj3ZNg" Received: from [127.0.0.1] (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: marcan@marcan.st) by mail.marcansoft.com (Postfix) with ESMTPSA id 056C441EA7; Tue, 26 Nov 2024 18:24:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=marcan.st; s=default; t=1732645452; bh=hF79OJOTF3Zhn8zXCNMfZBZW+wmNbw9AS1gO9o5YyZY=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=DrCj3ZNgdTLjEa6WgNpslR3Re7kRLIDW/oSjyfdbX0rhfHJ0NMtMr7MEJE3X0qemC jMGWqS8HVlaoEQ+GBcLBPC8IdI6jijrOIbFHhuMQqCp3xr5CA3v/MKisPcTbgoz62G av58lvd/TZ3KUf0e2hzo3w7Ms9Xer9NcHuuf2A5yVX7hG3d42yNe/rBAHQt+NeZ7C6 QSNbywgdmfFTE8fhM839bRIb2gWqFdwSwkpoLrSxSLltENbqhA0LQScpQ1CHh//2xT sm9B97wLh93yuzi0C6IDiR+Utp9Ny2HYms+SgANp7VHPuWEv0UIx7KspScgs8X0UBA +ouOVcHInABAQ== Message-ID: <3906a62b-3fb0-4ff7-bf0f-ae72009d3bc3@marcan.st> Date: Wed, 27 Nov 2024 03:24:09 +0900 Precedence: bulk X-Mailing-List: asahi@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/5] dt-bindings: display: Add Apple pre-DCP display controller bindings To: Krzysztof Kozlowski , Sasha Finkelstein Cc: Sven Peter , Alyssa Rosenzweig , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Neil Armstrong , Jessica Zhang , asahi@lists.linux.dev, linux-arm-kernel@lists.infradead.org, dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org References: <20241126-adpdrm-v2-0-c90485336c09@gmail.com> <20241126-adpdrm-v2-1-c90485336c09@gmail.com> <050d1398-cfc2-4921-b82a-95eecbcddba4@kernel.org> From: Hector Martin Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 2024/11/27 2:20, Krzysztof Kozlowski wrote: > On 26/11/2024 18:00, Sasha Finkelstein wrote: >> On Tue, 26 Nov 2024 at 17:46, Krzysztof Kozlowski wrote: >>>> +properties: >>>> + compatible: >>>> + items: >>>> + - enum: >>>> + - apple,j293-summit >>>> + - apple,j493-summit >>>> + - const: apple,summit >>> >>> Summit tells me nothing - no description, title repeats it, so I suggest >>> using device specific compatible. >> >> The j293/j493 are the device-specific compatibles, those are chassis names >> for the specific laptops the panel is present in. > > This does not address my comment. Use specific compatibles as fallback, > just like we recommend for every device. This should not be different. > If you do not know the hardware details, using generic is even less > appropriate. The panel is codenamed "summit", and that tells you everything. It's a panel sold and marketed by Apple. It is used on two devices, which are specifically referred to as the device names "j293" and "j493". There is no further information to be added here, the names chosen already contain 100% of the available information and are completely and fully specific as to what devices are involved here. There is no more specific or appropriate compatible possible. "summit" literally comes from Apple's own device tree compatible in the macOS world, which is "lcd,summit". If Apple uses it as a DT compatible, then it's a good bet it is precisely what it needs to be to identify a device. The chassis-specific versions are something we added on top of that and likely aren't even necessary since it's almost certainly precisely the same exact panel in both laptops, but as you know, it's best to be specific with DT compatibles just in case. There is plenty of prior art for compatibles that don't look like random product code gobbledygook (which I think is what you were expecting?), e.g. these panels: ti,nspire-cx-lcd-panel ste,mcde-dsi raspberrypi,7inch-touchscreen-panel olimex,lcd-olinuxino focaltech,gpt3 So yeah, the correct compatible is in fact "apple,summit". Anything else would be making things up for no reason. The vendor has chosen to call this panel "summit", so "summit" it is. We're not in the business of gratuitously assigning our own product names/codes when a suitable one already exists here. - Hector