Hi Rob,
Am 18.12.2019 um 22:16 schrieb Rob Herring robh@kernel.org:
On Tue, Dec 17, 2019 at 07:01:59PM +0100, H. Nikolaus Schaller wrote:
The Imagination PVR/SGX GPU is part of several SoC from multiple vendors, e.g. TI OMAP, Ingenic JZ4780, Intel Poulsbo and others.
With this binding, we describe how the SGX processor is interfaced to the SoC (registers, interrupt etc.).
In most cases, Clock, Reset and power management is handled by a parent node or elsewhere.
Tested by make dt_binding_check dtbs_check
I'm surprised that worked... (Not for long if it did).
AFAIR, it did not fail but emit thousands of warnings for other areas so I may have missed some warning but there was no error that did stop compilation.
Signed-off-by: H. Nikolaus Schaller hns@goldelico.com
.../devicetree/bindings/gpu/img,pvrsgx.yaml | 80 +++++++++++++++++++ 1 file changed, 80 insertions(+) create mode 100644 Documentation/devicetree/bindings/gpu/img,pvrsgx.yaml
diff --git a/Documentation/devicetree/bindings/gpu/img,pvrsgx.yaml b/Documentation/devicetree/bindings/gpu/img,pvrsgx.yaml new file mode 100644 index 000000000000..44799774e34d --- /dev/null +++ b/Documentation/devicetree/bindings/gpu/img,pvrsgx.yaml @@ -0,0 +1,80 @@ +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/gpu/img,pvrsgx.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml#
+title: Imagination PVR/SGX GPU
+maintainers:
- H. Nikolaus Schaller hns@goldelico.com
+description: |+
- This binding describes the Imagination SGX5 series of 3D accelerators which
- are found in several different SoC like TI OMAP, Sitara, Ingenic JZ4780,
- Allwinner A83, and Intel Poulsbo and CedarView and more.
- For an almost complete list see: https://en.wikipedia.org/wiki/PowerVR#Implementations
- Only the Imagination SGX530, SGX540 and SGX544 GPUs are currently covered by
- this binding but the extension of the pattern is straightforward.
- The SGX node is usually a child node of some DT node belonging to the SoC
- which handles clocks, reset and general address space mapping of the SGX
- register area.
+properties:
- compatible:
- enum:
- # Example: BeagleBoard A/B/C, OpenPandora 600MHz
- ti,omap3-sgx530-121, img,sgx530-121, img,sgx530Didn't I comment before this is not valid.
Not that I am aware of. Your comment was:
<<<
+properties:
- compatible:
- enum:
- # BeagleBoard ABC, OpenPandora 600MHz
I'd expect compatibles to be per SoC, not per board.
- ti,omap3-sgx530-121, img,sgx530-121, img,sgx530, img,sgx5
4 compatibles is probably a bit much. Are there not any version or feature registers that some of this could be detected? If there are, I'd assume the middle 2 strings could be dropped. If not, drop the last one and just match on the 3rd string. It's not a long list.
So I interpreted your comment is about the # comment focussing too much on boards instead of SoC and about dropping img,sgx5
You are defining the compatible string is: 'ti,omap3-sgx530-121, img,sgx530-121, img,sgx530'
Yes.
You need:
compatible: oneOf:
- description: BeagleBoard A/B/C, OpenPandora 600MHz items:
- const: ti,omap3-sgx530-121
- const: img,sgx530-121
- const: img,sgx530
And so on for each of the rest.
Hm. As far as I understand YAML, it has multiple ways to define the same structure but this manifold nature has its drawbacks.
If it is wrong I have to admit that I still do not understand how to write correct schemes... Why has it been made so difficult for us developers?
- # Example: BeagleBoard XM, GTA04, OpenPandora 1GHz
- ti,omap3-sgx530-125, img,sgx530-125, img,sgx530- # Example: BeagleBone Black
- ti,am3352-sgx530-125, img,sgx530-125, img,sgx530These 2 could be combined using 'enum' for the first item. Basically, you can group ones where the last 2 strings are the same.
Is this better readable?
IMHO, this would be a nice coding trick that would make this even more unreadable and does not add any new information.
Generally, in my opinion, a bindings document should not only satisfy the dtbs_check but should be human readable (and writeable!) so that a DTS developer can still understand and ideally copy&paste fragments. With such enum tricks and -items const: constructions this IMHO becomes more difficult.
Therefore I think the linear list is better readable and can be directly copied. If the test rig has problems with that statement, I would suggest that the parser should be modified to understand what we can easily write and read.
The same is for # comment vs. description: . The # comment is for a human reader of this document to get a hint what board the next line is intended for. It is not necessary (and IMHO impossible) to automatically test it. So I do not see any need to add a formal -description entry here.
- # Example: Pandaboard, Pandaboard ES
- ti,omap4-sgx540-120, img,sgx540-120, img,sgx540- ti,omap4-sgx544-112, img,sgx544-112, img,sgx544- # Example: OMAP5 UEVM, Pyra Handheld
- ti,omap5-sgx544-116, img,sgx544-116, img,sgx544- ti,dra7-sgx544-116, img,sgx544-116, img,sgx544- # Example: CI20
- ingenic,jz4780-sgx540-120, img,sgx540-120, img,sgx540- # the following entries are not validated with real hardware
What am I supposed to do with that? You're just defining some strings. If you're not sure they are okay, then don't define them.
I have a broader audience in mind than 'make dtbs_check'. IMHO, this document should help future developers to get an idea what to write for those SoC. Yes, it might not be 100% correct, but it is easier to correct a 99% correct definition than inventing it from scratch after dropping partially correct information I already have.
For example, we know from data sheets and public information that the allwinner a83 contains a sgx544 but it is not sure if it is the -116 variant. Or, the poulsbo has a GPU called gma500 which is an sgx535. It is only that nobody has verified this so far by real hardware.
If we leave it out and someone starts to adapt this to the poulsbo in let's say 2 years from now, that someone has to be lucky to find our discussion here and take that as a hint.
I am not sure how you are developing contributions, but my first place to start with is the existing code and not the archives of LKML.
That is my motivation adding these records right here even if they are not verified.
- # more TI SoC
- ti,am3517-sgx530-125, img,sgx530-125, img,sgx530- ti,am4-sgx530-125, img,sgx530-125, img,sgx530- ti,ti81xx-sgx530-125, img,sgx530-125, img,sgx530- # Example: Banana-Pi-M3 (Allwinner A83T)
- allwinner,sun8i-a83t-sgx544-116, img,sgx544-116, img,sgx544- # Example: Atom Z5xx
- intel,poulsbo-gma500-sgx535, img,sgx535-116, img,sgx535- # Example: Atom Z24xx
- intel,medfield-gma-sgx540, img,sgx540-116, img,sgx540- # Example: Atom N2600, D2500
- intel,cedarview-gma3600-sgx545, img,sgx545-116, img,sgx545- reg:
- maxItems: 1
- interrupts:
- maxItems: 1
+required:
- compatible
- reg
- interrupts
+additionalProperties: false
+examples:
- |+
- #include <dt-bindings/interrupt-controller/arm-gic.h>
- gpu@fe00 {
compatible = "ti,omap-omap5-sgx544-116", "img,sgx544-116", "img,sgx544", "img,sgx5";Doesn't match the schema.
Ah, thanks. I missed that when reviewing the DTS patch set. Queued for a v5.
reg = <0xfe00 0x200>;interrupts = <GIC_SPI 21 IRQ_TYPE_LEVEL_HIGH>;- };
+...
2.23.0
BR and thanks, Nikolaus