Re: [PATCH v3 2/4] dt-bindings: pwm: amlogic: add new compatible for meson8 pwm type
From: neil . armstrong
Date: Wed Nov 29 2023 - 12:02:50 EST
Hi,
On 29/11/2023 17:26, Jerome Brunet wrote:
On Wed 29 Nov 2023 at 17:20, Neil Armstrong <neil.armstrong@xxxxxxxxxx> wrote:
Hi,
On 29/11/2023 14:39, Jerome Brunet wrote:
Add a new compatible for the pwm found in the meson8 to sm1 Amlogic SoCs,
dealing with clocks differently. This does not enable new HW. It is meant
to fix a bad DT ABI for the currently supported HW.
The original clock bindings describe which input the PWM channel
multiplexer should pick among its possible parents, which are
hard-coded in the driver. As such, it is a setting tied to the driver
implementation and does not describe the HW.
The new bindings introduce here describe the clocks input of the PWM
block
as they exist.
The old compatible is deprecated but kept to maintain ABI compatibility.
The SoC specific compatibles introduced match the SoC families supported
by the original bindings.
Signed-off-by: Jerome Brunet <jbrunet@xxxxxxxxxxxx>
---
.../devicetree/bindings/pwm/pwm-amlogic.yaml | 52 ++++++++++++++++---
1 file changed, 46 insertions(+), 6 deletions(-)
diff --git a/Documentation/devicetree/bindings/pwm/pwm-amlogic.yaml
b/Documentation/devicetree/bindings/pwm/pwm-amlogic.yaml
index 387976ed36d5..eece390114a3 100644
--- a/Documentation/devicetree/bindings/pwm/pwm-amlogic.yaml
+++ b/Documentation/devicetree/bindings/pwm/pwm-amlogic.yaml
@@ -21,23 +21,35 @@ properties:
- amlogic,meson-g12a-ee-pwm
- amlogic,meson-g12a-ao-pwm-ab
- amlogic,meson-g12a-ao-pwm-cd
- - amlogic,meson-s4-pwm
+ deprecated: true
- items:
- const: amlogic,meson-gx-pwm
- const: amlogic,meson-gxbb-pwm
+ deprecated: true
- items:
- const: amlogic,meson-gx-ao-pwm
- const: amlogic,meson-gxbb-ao-pwm
+ deprecated: true
- items:
- const: amlogic,meson8-pwm
- const: amlogic,meson8b-pwm
+ deprecated: true
I think deprecated should be moved in a third patch
The complain on v2 was that it was not clear the new binding was making
the old one obsolete. It looked to me that the deprecation old bindings
needed to go together with the introduction of the new.
I don't mind one way or the other
Is there a rule somewhere about this ?
Not sure about that, I don't think it's a problem to have both valid
at the same time, setting them deprecated afterwards looks cleaner
to avoid mixing too much changes at the same time.
Neil
+ - const: amlogic,meson8-pwm-v2
+ - items:
+ - enum:
+ - amlogic,meson8b-pwm-v2
+ - amlogic,meson-gxbb-pwm-v2
+ - amlogic,meson-axg-pwm-v2
+ - amlogic,meson-g12-pwm-v2
+ - const: amlogic,meson8-pwm-v2
+ - const: amlogic,meson-s4-pwm
reg:
maxItems: 1
clocks:
minItems: 1
- maxItems: 2
+ maxItems: 4
clock-names:
minItems: 1
@@ -58,7 +70,6 @@ allOf:
compatible:
contains:
enum:
- - amlogic,meson8-pwm
- amlogic,meson8b-pwm
- amlogic,meson-gxbb-pwm
- amlogic,meson-gxbb-ao-pwm
@@ -67,14 +78,15 @@ allOf:
- amlogic,meson-g12a-ee-pwm
- amlogic,meson-g12a-ao-pwm-ab
- amlogic,meson-g12a-ao-pwm-cd
- - amlogic,meson-gx-pwm
- - amlogic,meson-gx-ao-pwm
I don't understand why those entries are removed
It's a mistake. It should not have been added to begin with in
the first patch. "amlogic,meson-gx-*" must go along with
"amlogic,meson-gxbb-*" so it matches correctly without it.
I'll fix it
then:
- # Historic bindings tied to the driver implementation
+ # Obsolete historic bindings tied to the driver implementation
# The clocks provided here are meant to be matched with the input
# known (hard-coded) in the driver and used to select pwm clock
# source. Currently, the linux driver ignores this.
+ # This is kept to maintain ABI backward compatibility.
Same here, this should go in a third patch
properties:
+ clocks:
+ maxItems: 2
clock-names:
oneOf:
- items:
@@ -83,6 +95,27 @@ allOf:
- const: clkin0
- const: clkin1
+ # Newer binding where clock describe the actual clock inputs of the
pwm
+ # block. These are necessary but some inputs may be grounded.
+ - if:
+ properties:
+ compatible:
+ contains:
+ enum:
+ - amlogic,meson8-pwm-v2
+ then:
+ properties:
+ clocks:
+ minItems: 1
+ items:
+ - description: input clock 0 of the pwm block
+ - description: input clock 1 of the pwm block
+ - description: input clock 2 of the pwm block
+ - description: input clock 3 of the pwm block
+ clock-names: false
+ required:
+ - clocks
+
# Newer IP block take a single input per channel, instead of 4 inputs
# for both channels
- if:
@@ -112,6 +145,13 @@ examples:
clock-names = "clkin0", "clkin1";
#pwm-cells = <3>;
};
+ - |
+ pwm@2000 {
+ compatible = "amlogic,meson8-pwm-v2";
+ reg = <0x1000 0x10>;
+ clocks = <&xtal>, <0>, <&fdiv4>, <&fdiv5>;
+ #pwm-cells = <3>;
+ };
- |
pwm@1000 {
compatible = "amlogic,meson-s4-pwm";
Neil