Hi Heiko,

On Wed, Jul 12, 2017 at 08:30:55PM +0200, Heiko Stuebner wrote:

Am Mittwoch, 12. Juli 2017, 10:26:39 CEST schrieb Brian Norris:

quoted

On Wed, May 03, 2017 at 10:56:25AM +0100, Guillaume Tucker wrote:

quoted

The ARM Mali Midgard GPU family is present in a number of SoCs
from many different vendors such as Samsung Exynos and Rockchip.

Import the device tree bindings documentation from the r16p0

release of the Mali Midgard GPU kernel driver:
  https://developer.arm.com/-/media/Files/downloads/mali-drivers/kernel/ma
  li-midgard-gpu/TX011-SW-99002-r16p0-00rel0.tgz> 
Remove the copyright and GPL licence header as deemed not necessary.

Redesign the "compatible" property strings to list all the Mali
Midgard GPU types and add vendor specific ones.

Drop the "clock-names" property as the Mali Midgard GPU uses only one
clock (the driver now needs to call clk_get with NULL).

Convert the "interrupt-names" property values to lower-case: "job",
"mmu" and "gpu".

Replace the deprecated "operating-points" optional property with
"operating-points-v2".

Omit the following optional properties in this initial version as they

are only used in very specific cases:
  * snoop_enable_smc
  * snoop_disable_smc
  * jm_config
  * power_model
  * system-coherency
  * ipa-model

Update the example accordingly to reflect all these changes, based on
rk3288 mali-t760.

CC: John Reitan <redacted>
Tested-by: Enric Balletbo i Serra <redacted>
Signed-off-by: Guillaume Tucker <redacted>
---

 .../devicetree/bindings/gpu/arm,mali-midgard.txt   | 86
 ++++++++++++++++++++++ 1 file changed, 86 insertions(+)
 create mode 100644
 Documentation/devicetree/bindings/gpu/arm,mali-midgard.txt> 

diff --git a/Documentation/devicetree/bindings/gpu/arm,mali-midgard.txt

b/Documentation/devicetree/bindings/gpu/arm,mali-midgard.txt new file
mode 100644
index 000000000000..d3b6e1a4713a

--- /dev/null
+++ b/Documentation/devicetree/bindings/gpu/arm,mali-midgard.txt

^^ This file name implies we're talking about a base "arm,mali-midgard"
compatible property.

it follows the precedent of arm,mali-utgard.txt and while the file-name
is not part of the compatible list, it feels way better collecting all the 
variants in one file, compared to spawning multiple ones for each soc
vendor using a mali gpu.

Also in other places the naming of binding descriptions does not follow
any compatible at all, so the filename = main-compatible does not seem
to be the rule.

Well, when they do get a name in the form of "<vendor>,<foo>.txt", the
"<vendor>,<foo>" is usually at least *a* valid compatible string. For
example, "nvidia,gk20a.txt" has several other strings, but its filename
is one of the supported ones.

Anyway, that wasn't my main worry. I was mostly curious about the body
of the text.

quoted

quoted

@@ -0,0 +1,86 @@
+ARM Mali Midgard GPU
+====================
+
+Required properties:
+
+- compatible :
+  * Must contain one of the following:
+    + "arm,mali-t604"
+    + "arm,mali-t624"
+    + "arm,mali-t628"
+    + "arm,mali-t720"
+    + "arm,mali-t760"
+    + "arm,mali-t820"
+    + "arm,mali-t830"
+    + "arm,mali-t860"
+    + "arm,mali-t880"
+  * which must be preceded by one of the following vendor specifics:
+    + "amlogic,meson-gxm-mali"
+    + "rockchip,rk3288-mali"

But it's not listed here.

quoted

+
+- reg : Physical base address of the device and length of the register
area. +
+- interrupts : Contains the three IRQ lines required by Mali Midgard
devices. +
+- interrupt-names : Contains the names of IRQ resources in the order they
were +  provided in the interrupts property. Must contain: "job", "mmu",
"gpu". +
+
+Optional properties:
+
+- clocks : Phandle to clock for the Mali Midgard device.
+
+- mali-supply : Phandle to regulator for the Mali device. Refer to
+  Documentation/devicetree/bindings/regulator/regulator.txt for details.
+
+- operating-points-v2 : Refer to
Documentation/devicetree/bindings/power/opp.txt +  for details.
+
+
+Example for a Mali-T760:
+
+gpu at ffa30000 {
+	compatible = "rockchip,rk3288-mali", "arm,mali-t760",
"arm,mali-midgard";

And it *is* used here in this example.

So, should it be used/documented or not?

No I don't think it should and have patches that drop the mali-midgard from
the example + rk3288 dtsi to not confuse people:
- https://patchwork.kernel.org/patch/9832811/
- https://patchwork.kernel.org/patch/9832807/

I didn't notice those. Thanks.

Devicetree supposedly should not contain wildcards and without knowing
for real that all of then in fact are compatible we should not assume so
[and that's hard to check with all the secrecy :-) ] . Using the real name 
(tXXX) sounds nice enough.

Fine with me.

Brian