Re: [PATCH v11 3/5] dt-bindings: clock: meson: add A1 PLL and Peripherals clkcs bindings

From: neil . armstrong
Date: Mon Mar 27 2023 - 09:55:57 EST


On 27/03/2023 15:19, Dmitry Rokosov wrote:
On Mon, Mar 27, 2023 at 02:03:25PM +0200, neil.armstrong@xxxxxxxxxx wrote:
On 27/03/2023 13:39, Jerome Brunet wrote:

On Mon 27 Mar 2023 at 13:51, Dmitry Rokosov <ddrokosov@xxxxxxxxxxxxxx> wrote:

On Mon, Mar 27, 2023 at 11:51:21AM +0200, Jerome Brunet wrote:

On Tue 21 Mar 2023 at 22:30, Dmitry Rokosov <ddrokosov@xxxxxxxxxxxxxx> wrote:

Add the documentation for Amlogic A1 PLL and Amlogic A1 Peripherals
clock drivers.
Introduce Amlogic A1 PLL and Amlogic A1 Peripherals device tree
bindings and include them to MAINTAINERS.

Signed-off-by: Jian Hu <jian.hu@xxxxxxxxxxx>
Signed-off-by: Dmitry Rokosov <ddrokosov@xxxxxxxxxxxxxx>
---
.../bindings/clock/amlogic,a1-clkc.yaml | 73 +++++++++++
.../bindings/clock/amlogic,a1-pll-clkc.yaml | 59 +++++++++
MAINTAINERS | 1 +
include/dt-bindings/clock/amlogic,a1-clkc.h | 113 ++++++++++++++++++
.../dt-bindings/clock/amlogic,a1-pll-clkc.h | 21 ++++
5 files changed, 267 insertions(+)
create mode 100644 Documentation/devicetree/bindings/clock/amlogic,a1-clkc.yaml
create mode 100644 Documentation/devicetree/bindings/clock/amlogic,a1-pll-clkc.yaml

There is two drivers (and 2 independent patches). There should be 2
bindings patches as well.


Before, in previous versions I had two versions, but it wasn't bisectable
approach.

You are confusing bisectable and Rob's robot. Splitting patches is more
that likely to help bisect (and patches backport) - not the other way around.

a1-clkc schema depends on a1-pll-clkc headers and vice versa.
It means dt schemas checkers will show us failure if we split them into two
patchsets.

Only because you are patches are not upstream yet ...

I know, that we can use raw digits instead of CLKID names, but IMO it doesn't
look like production schema and it requires one more patchset above the
series with proper CLKID definitons usage and proper header including.

BTW, there is an example of Rob's test bot failure found in the previous
v10 patch series due to chicken or the egg problem.
https://lore.kernel.org/all/167769997208.7087.5344356236212731922.robh@xxxxxxxxxx/

Please advise what's the best practice to resolve that..

Don't use the header in your example would solve the problem and
still be correct DT wise.

The examples are just examples, they are not required to actually
matches a real HW, as far as I know.

Exact, you can use fake lables instead of defined:

<&clkc_pll CLKID_FCLK_DIV2>,

=>
remove "#include <dt-bindings/clock/amlogic,a1-pll-clkc.h>"

<&clkc_pll_fclk_div2>,

is perfectly ok and will permit have 2 separate patches.

The dependency is only if you have a common yaml file for
both bindings files, but this is not the case here.

Simple removal of "#include <dt-bindings/clock/amlogic,a1-pll-clkc.h>"
header doesn't work, dt_binding_check make rule is failed:

I never wrote you to only remove the include, adding fake labels phandles was the logical next step.

Neil


Error: Documentation/devicetree/bindings/clock/amlogic,a1-clkc.example.dts:28.37-38 syntax error
FATAL ERROR: Unable to parse input tree

It happens, because 'dt_binding_check' generates simple dts example and
tries to compile it:

cat Documentation/devicetree/bindings/clock/amlogic,a1-clkc.example.dts
===

/dts-v1/;
/plugin/; // silence any missing phandle references


/{
compatible = "foo";
model = "foo";
#address-cells = <1>;
#size-cells = <1>;



example-0 {
#address-cells = <1>;
#size-cells = <1>;


apb {
#address-cells = <2>;
#size-cells = <2>;
clock-controller@800 {
compatible = "amlogic,a1-clkc";
reg = <0 0x800 0 0x104>;
#clock-cells = <1>;
clocks = <&clkc_pll CLKID_FCLK_DIV2>,
<&clkc_pll CLKID_FCLK_DIV3>,
<&clkc_pll CLKID_FCLK_DIV5>,
<&clkc_pll CLKID_FCLK_DIV7>,
<&clkc_pll CLKID_HIFI_PLL>,
<&xtal>;
clock-names = "fclk_div2", "fclk_div3",
"fclk_div5", "fclk_div7",
"hifi_pll", "xtal";
};
};

};
};
===

As you can see, header is required.

But looks like, dt binding checker is happy with the fake references hack :)
Below there is generated example dts:

cat Documentation/devicetree/bindings/clock/amlogic,a1-clkc.example.dts
===

/dts-v1/;
/plugin/; // silence any missing phandle references


/{
compatible = "foo";
model = "foo";
#address-cells = <1>;
#size-cells = <1>;



example-0 {
#address-cells = <1>;
#size-cells = <1>;


apb {
#address-cells = <2>;
#size-cells = <2>;
clock-controller@800 {
compatible = "amlogic,a1-clkc";
reg = <0 0x800 0 0x104>;
#clock-cells = <1>;
clocks = <&clkc_pll_fclk_div2>,
<&clkc_pll_fclk_div3>,
<&clkc_pll_fclk_div5>,
<&clkc_pll_fclk_div7>,
<&clkc_pll_hifi_pll>,
<&xtal>;
clock-names = "fclk_div2", "fclk_div3",
"fclk_div5", "fclk_div7",
"hifi_pll", "xtal";
};
};

};
};
===

Yep, we are able to cheat dt checkers, but we don't help dt developers
with such example.
May be, it's better to prepare two patches in such hierarchy:

1) A1 PLL clkc bindings with fake references without clkc headers
2) A1 clkc bindings with real CLKID bindings + A1 PLL clkc bindings fix
with real CLKID A1 clkc bindings + header.

The such approach resolves DT checkers failures and split DT bindings
into two patchsets.

[...]