Hi, Matthias & Enric:
On Fri, 2020-02-14 at 13:19 +0100, Enric Balletbo i Serra wrote:
Hi CK,
On 14/2/20 11:01, Matthias Brugger wrote:
On 14/02/2020 07:42, CK Hu wrote:
Hi, Matthias:
On Thu, 2020-02-13 at 21:19 +0100, matthias.bgg@kernel.org wrote:
From: Matthias Brugger mbrugger@suse.com
The mmsys block provides registers and clocks for the display subsystem. The binding description should therefore live together with the rest of the display descriptions. Move it to display/mediatek.
Yes, for the upstreamed driver, only display (DRM) use mmsys clock. For some MDP patches [1] in progress, MDP also use mmsys clock. So we just consider what's upstreamed now?
Let me jump into the discussion, and sorry if my question is silly because I'm just starting to look at this code.
IMO we should consider all the cases to find a proper fix on all this, and if MDP uses also mmsys clocks this approach will not work. I think the main problem here and the big question is what exactly is the MMSYS block, is an independent clock controller that provides clocks to DRM and other blocks? or is hardly tied to the DRM block in some way?
Could you give us a block schema on how the things are interconnected?
If is an independent clock controller I think there was a mistake when the first drm driver was pushed by using the compatible = "mediatek,mt8173-mmsys" as id for that driver.
I correct my mistake first. In mt8173, mdp has already upstreamed [1].
There are many partitions in Mediatek SoC. mmsys is one of these partition. There are many function blocks in mmsys such as OVL, RDMA, RSZ, WROT, .... Some data routing between these blocks are fixed but some are changeable. For application, we group them into display path and mdp path. Clock gating register of these blocks are in the range of 0x14000000 ~ 0x14000fff. The routing control register of these blocks are also in the range of 0x14000000 ~ 0x14000fff. So the control function belong to mmsys partition but not belong to specific function block would in the register range of 0x14000000 ~ 0x14000fff. I think there could be two definition of mmsys device. One is that mmsys device is the whole mmsys partiotion, so OVL, RDMA, ... would be sub device of it. Another is that mmsys just control register of 0x14000000 ~ 0x14000fff, so it's part of mmsys partition like OVL, RDMA, ..... Currently we define mmsys as the latter one. I've no idea how to map mmsys into current Linux hardware category, but I think it is not just a display device.
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch...
Regards, CK
Thanks, Enric
I'm not sure if I understand you correctly. Are you proposing to keep the binding description in arm/mediatek?
Regards, Matthias
[1] https://patchwork.kernel.org/patch/11140747/
Regards, CK
Signed-off-by: Matthias Brugger mbrugger@suse.com
Changes in v7:
- move the binding description
Changes in v6: None Changes in v5: None Changes in v4: None Changes in v3: None Changes in v2: None
.../bindings/{arm => display}/mediatek/mediatek,mmsys.txt | 0 1 file changed, 0 insertions(+), 0 deletions(-) rename Documentation/devicetree/bindings/{arm => display}/mediatek/mediatek,mmsys.txt (100%)
diff --git a/Documentation/devicetree/bindings/arm/mediatek/mediatek,mmsys.txt b/Documentation/devicetree/bindings/display/mediatek/mediatek,mmsys.txt similarity index 100% rename from Documentation/devicetree/bindings/arm/mediatek/mediatek,mmsys.txt rename to Documentation/devicetree/bindings/display/mediatek/mediatek,mmsys.txt
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