Re: [PATCH v2 1/5] dt-bindings: display: simple-framebuffer: Add interconnects property
From: Thomas Zimmermann <tzimmermann@suse.de>
Date: 2025-06-30 06:34:29
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dri-devel, linux-devicetree, lkml
Hi Am 28.06.25 um 13:50 schrieb Krzysztof Kozlowski:
On 27/06/2025 13:34, Thomas Zimmermann wrote:quoted
Hi Am 27.06.25 um 10:08 schrieb Krzysztof Kozlowski: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.In this context, 'simple' means that this device cannot change display modes or do graphics acceleration. The hardware itself is not necessarily simple. As Javier pointed out, it's initialized by firmwareIf hardware is not simple, then it needs specific bindings.quoted
on the actual hardware. Think of 'VGA-for-ARM'. We need these resources to keep the display working.I don't claim you do not need these resources. I claim device is not simple thus does not suit rules for generic bindings. Generic bindings are in general not allowed and we have them only for very, very simple devices. You say this is not simple device, so there you go - specific binding for this complex (not-simple) device.
No, I didn't. I said that the device is simple. I did not say that the device's hardware is simple. Sounds nonsensical, but makes sense here. The simple-framebuffer is just the range of display memory that the firmware configured for printing boot-up messages. We use it for the kernel's output as well. Being generic and simple is the exact raison d'etre for simple-framebuffer. (The display property points to the actual hardware, but we don't need it.) Best regards Thomas
Best regards, Krzysztof
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