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 73E74221286; Mon, 30 Jun 2025 08:24:15 +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=1751271856; cv=none; b=BjsIFR+84f8WnAVNTpIqZ/GFUeInLoa6x1tHEIz865NES5BQu/hY2/eoFrBJU9+FBWrmxooyY6Uym3NhgdBZiuUH6cfaW2pjVCW32s9HTxX+GUXRSlBqG6oQolMuf5kLEgWSi2fZjMSlA0/9Wc5cd0b6o462akNTZicF4wKEEAk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751271856; c=relaxed/simple; bh=KnqdYmSo9s5NiZ0efI74+ehXh+hBILnC72jZRK1fvLM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=e7IOZi1n6c/LL+cx5AaZ6ghpjsBZJ9+PT2rRgAHALY7H/y8RTRXeoFaOqie9I30CAJ31xAGEucr2njp1qvNewhqWEfEDxYOWO/3HLwWS6eOrxQFNssIeXb9g77y0jI9cAVfadc7kOQppcCKlPipM7uUD6TNfEd9NSaiNKUYeyXs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=r+Bb7Inn; 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="r+Bb7Inn" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2659CC4CEE3; Mon, 30 Jun 2025 08:24:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1751271854; bh=KnqdYmSo9s5NiZ0efI74+ehXh+hBILnC72jZRK1fvLM=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=r+Bb7Inn8Vy22KXD38198pUWEe8FBp2sBCqQ/yUmybovKrqN9wygoCuEuRVC5SMm2 gm5xd3AkSqygRW7xfmyOBN6Csv2e8N44KurbNvRX+ALrOeI1elU4d5Q+a1lIXLnoR6 0Q3rUcmlKktOzdHPRgv7FLNFvu4prXlIcGskbjkE7UphuvtsJJP65JhMGMUOYs5Cqi 2LYK52Rve1YoVwrRXIw1UUyWvAzX7AioHPSu2chfAnP9EYo4++db3BEsed0ItGEzzL 7znY+g/b6ynYiqNdOLnrUTGNdZARlYsWenJDUc21bFeLYj3jl7jOyCVQVTET9p3kDe lKhTxR/iCX6iw== Message-ID: <85521ded-734d-48e8-8f76-c57739102ded@kernel.org> Date: Mon, 30 Jun 2025 10:24:06 +0200 Precedence: bulk X-Mailing-List: linux-fbdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/5] dt-bindings: display: simple-framebuffer: Add interconnects property To: Hans de Goede , Luca Weiss Cc: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Javier Martinez Canillas , Helge Deller , linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org References: <20250623-simple-drm-fb-icc-v2-0-f69b86cd3d7d@fairphone.com> <20250623-simple-drm-fb-icc-v2-1-f69b86cd3d7d@fairphone.com> <20250627-mysterious-optimistic-bird-acaafb@krzk-bin> <1129bc60-f9cb-40be-9869-8ffa3b3c9748@kernel.org> <8a3ad930-bfb1-4531-9d34-fdf7d437f352@redhat.com> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 29/06/2025 14:07, Hans de Goede wrote: > Hi Krzysztof, > > On 28-Jun-25 1:49 PM, Krzysztof Kozlowski wrote: >> On 27/06/2025 11:48, Luca Weiss wrote: >>> Hi Krzysztof, >>> >>> On Fri Jun 27, 2025 at 10:08 AM CEST, Krzysztof Kozlowski wrote: >>>> On Mon, Jun 23, 2025 at 08:44:45AM +0200, Luca Weiss wrote: >>>>> Document the interconnects property which is a list of interconnect >>>>> paths that is used by the framebuffer and therefore needs to be kept >>>>> alive when the framebuffer is being used. >>>>> >>>>> Acked-by: Thomas Zimmermann >>>>> Signed-off-by: Luca Weiss >>>>> --- >>>>> Documentation/devicetree/bindings/display/simple-framebuffer.yaml | 3 +++ >>>>> 1 file changed, 3 insertions(+) >>>>> >>>>> diff --git a/Documentation/devicetree/bindings/display/simple-framebuffer.yaml b/Documentation/devicetree/bindings/display/simple-framebuffer.yaml >>>>> index 296500f9da05e296dbbeec50ba5186b6b30aaffc..f0fa0ef23d91043dfb2b220c654b80e2e80850cd 100644 >>>>> --- a/Documentation/devicetree/bindings/display/simple-framebuffer.yaml >>>>> +++ b/Documentation/devicetree/bindings/display/simple-framebuffer.yaml >>>>> @@ -79,6 +79,9 @@ properties: >>>>> power-domains: >>>>> description: List of power domains used by the framebuffer. >>>>> >>>>> + interconnects: >>>>> + description: List of interconnect paths used by the framebuffer. >>>>> + >>>> >>>> maxItems: 1, or this is not a simple FB anymore. Anything which needs >>>> some sort of resources in unknown way is not simple anymore. You need >>>> device specific bindings. >>> >>> The bindings support an arbitrary number of clocks, regulators, >>> power-domains. Why should I artificially limit the interconnects to only >>> one? >> >> And IMO they should not. Bindings are not supposed to be generic. > > The simplefb binding is a binding to allow keeping the firmware, e.g. > uboot setup framebuffer alive to e.g. show a boot splash until > the native display-engine drive loads. Needing display-engine > specific bindings totally contradicts the whole goal of No, it does not. DT is well designed for that through expressing compatibility. I did not say you cannot have generic fallback for simple use case. But this (and previous patchset) grows this into generic binding ONLY and that is not correct. > > It is generic by nature and I really do not see how clocks and > regulators are any different then interconnects here. Yeah, they are also wrong. I already commented on this. > > Note that we had a huge discussion about adding clock > and regulators to simplefb many years ago with pretty > much the same arguments against doing so. In the end it was > decided to add regulator and clocks support to the simplefb > bindings and non of the feared problems with e.g. ordening > of turning things on happened. > > A big part of this is that the claiming of clks / regulators / > interconnects by the simplefb driver is there to keep things on, > so it happens before the kernel starts tuning off unused resources > IOW everything is already up and running and this really is about > avoiding turning things off. No one asks to drop them from the driver. I only want specific front compatible which will list and constrain the properties. It is not contradictory to your statements, U-boot support, driver support. I really do not see ANY argument why this cannot follow standard DT rules. Best regards, Krzysztof