Re: [PATCH v2 1/5] dt-bindings: display: simple-framebuffer: Add interconnects property
From: Krzysztof Kozlowski <krzk@kernel.org>
Date: 2025-06-30 08:24:15
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On 29/06/2025 14:07, Hans de Goede wrote:
Hi Krzysztof, On 28-Jun-25 1:49 PM, Krzysztof Kozlowski wrote:quoted
On 27/06/2025 11:48, Luca Weiss wrote:quoted
Hi Krzysztof, On Fri Jun 27, 2025 at 10:08 AM CEST, Krzysztof Kozlowski wrote:quoted
On Mon, Jun 23, 2025 at 08:44:45AM +0200, Luca Weiss wrote:quoted
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 <tzimmermann@suse.de> Signed-off-by: Luca Weiss <redacted> --- 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