[PATCH v3 0/3] Add T7 PWM core clock support

[Ronald Claveau via B4 Relay]

The PWM controllers on the Amlogic S4 SoC have a system clock that
controls access to the controller, in addition to the two input
clocks of channels A and B. The A1,C3,T7 which fallback to S4 have
this third clock too.

It is currently not described in the device tree, so it is neither
referenced nor enabled by the driver.

This series adds support for it:

  - patch 1 extends the binding with a third "core" clock for
    amlogic,meson-s4-pwm, and makes clock-names required for it;
  - patch 2 makes the driver get and enable the optional "core"
    clock, leaving existing DTS' unaffected;
  - patch 3 describes the system clock in the A1-C3-S4-T7
    device tree for all the PWM controllers.

`dt_binding_check DT_SCHEMA_FILES=pwm-amlogic.yaml` test is ok

  CHKDT   ./Documentation/devicetree/bindings
warning: python package 'yamllint' not installed, skipping
  STYLE   ./Documentation/devicetree/bindings
  DTEX    Documentation/devicetree/bindings/pwm/pwm-amlogic.example.dts
  DTC [C] Documentation/devicetree/bindings/pwm/pwm-amlogic.example.dtb

Signed-off-by: Ronald Claveau <linux-kernel-dev at aliel.fr>
---
Changes in v3:
- PATCH 1: Require the third clock for S4 and all SoC which fallback to it.
- PATCH 3: Add the third clock to A1, C3 and S4.
- Link to v2: https://lore.kernel.org/r/20260925-add-t7-sys-pwm-clk-v2-0-f23a22b71a5c@aliel.fr

Changes in v2:
- PATCH 1: Permits to use "core" clock on S4 SoC and all the ones that fallback to it.
           Rename "clk_a" and "clk_b" to "channel-a" and "channel-b". Thx to Conor's feedback.
- PATCH 3: Rename channel clock-names as done on patch 1.
- Link to v1: https://lore.kernel.org/r/20260924-add-t7-sys-pwm-clk-v1-0-05b91e87f0a9@aliel.fr

---
Ronald Claveau (3):
      dt-bindings: pwm: amlogic: Add core clock for S4 like
      pwm: meson: Add optional core clock for S4 PWM
      arm64: dts: amlogic: a1-c3-s4-t7: Add core clock to PWM controller nodes

 .../devicetree/bindings/pwm/pwm-amlogic.yaml       | 21 +++++++++++++---
 arch/arm64/boot/dts/amlogic/amlogic-c3.dtsi        | 28 ++++++++++++++++------
 arch/arm64/boot/dts/amlogic/amlogic-t7.dtsi        | 28 ++++++++++++++++------
 arch/arm64/boot/dts/amlogic/meson-a1.dtsi          | 12 +++++++---
 arch/arm64/boot/dts/amlogic/meson-s4.dtsi          | 20 ++++++++++++----
 drivers/pwm/pwm-meson.c                            |  5 ++++
 6 files changed, 89 insertions(+), 25 deletions(-)
---
base-commit: f5f84daefcd92d7a630066635ecea1433ed5eac7
change-id: 20260924-add-t7-sys-pwm-clk-f0eff81bee21

Best regards,
-- 
Ronald Claveau <linux-kernel-dev at aliel.fr>