[v3,09/15] dt-bindings: pwm: add microchip corepwm binding

Commit Message

Conor Dooley Jan. 14, 2022, 3:17 p.m. UTC

From: Conor Dooley <[e-mail]>

Add device tree bindings for the Microchip fpga fabric based "core" PWM controller.

Signed-off-by: Conor Dooley <[e-mail]>
---
 .../bindings/pwm/microchip,corepwm.yaml       | 75 +++++++++++++++++++
 1 file changed, 75 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/pwm/microchip,corepwm.yaml

Comments

Rob Herring (Arm) Jan. 15, 2022, 5:22 p.m. UTC | #1

On Fri, 14 Jan 2022 15:17:21 +0000, [e-mail] wrote:
> From: Conor Dooley <[e-mail]>
> 
> Add device tree bindings for the Microchip fpga fabric based "core" PWM controller.
> 
> Signed-off-by: Conor Dooley <[e-mail]>
> ---
>  .../bindings/pwm/microchip,corepwm.yaml       | 75 +++++++++++++++++++
>  1 file changed, 75 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/pwm/microchip,corepwm.yaml
> 

My bot found errors running 'make DT_CHECKER_FLAGS=-m dt_binding_check'
on your patch (DT_CHECKER_FLAGS is new in v5.13):

yamllint warnings/errors:

dtschema/dtc warnings/errors:
Documentation/devicetree/bindings/pwm/microchip,corepwm.example.dts:19:18: fatal error: dt-bindings/clock/microchip,mpfs-clock.h: No such file or directory
   19 |         #include "dt-bindings/clock/microchip,mpfs-clock.h"
      |                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.
make[1]: *** [scripts/Makefile.lib:373: Documentation/devicetree/bindings/pwm/microchip,corepwm.example.dt.yaml] Error 1
make[1]: *** Waiting for unfinished jobs....
make: *** [Makefile:1413: dt_binding_check] Error 2

doc reference errors (make refcheckdocs):

See https://patchwork.ozlabs.org/patch/1580131

This check can fail if there are any dependencies. The base for a patch
series is generally the most recent rc1.

If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:

pip3 install dtschema --upgrade

Please check and re-submit.

Patch

diff --git a/Documentation/devicetree/bindings/pwm/microchip,corepwm.yaml b/Documentation/devicetree/bindings/pwm/microchip,corepwm.yaml
new file mode 100644
index 000000000000..26a77cde2465
--- /dev/null
+++ b/Documentation/devicetree/bindings/pwm/microchip,corepwm.yaml
@@ -0,0 +1,75 @@ 
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pwm/microchip,corepwm.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Microchip ip core PWM controller bindings
+
+maintainers:
+  - Conor Dooley <[e-mail]>
+
+description: |
+  corePWM is an 16 channel pulse width modulator FPGA IP
+
+  https://www.microsemi.com/existing-parts/parts/152118
+
+properties:
+  compatible:
+    items:
+      - const: microchip,corepwm-rtl-v4
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  "#pwm-cells":
+    const: 2
+
+  microchip,sync-update:
+    description: |
+      In synchronous mode, all channels are updated at the beginning of the PWM period.
+      Asynchronous mode is relevant to applications such as LED control, where
+      synchronous updates are not required. Asynchronous mode lowers the area size,
+      reducing shadow register requirements. This can be set at run time, provided
+      SHADOW_REG_EN is asserted. SHADOW_REG_EN is set by the FPGA bitstream programmed
+      to the device.
+      Each bit corresponds to a PWM channel & represents whether synchronous mode is
+      possible for the PWM channel.
+
+    $ref: /schemas/types.yaml#/definitions/uint16
+    default: 0
+
+  microchip,dac-mode:
+    description: |
+      Optional, per-channel Low Ripple DAC mode is possible on this IP core. It creates
+      a minimum period pulse train whose High/Low average is that of the chosen duty
+      cycle. This "DAC" will have far better bandwidth and ripple performance than the
+      standard PWM algorithm can achieve.
+      Each bit corresponds to a PWM channel & represents whether dac mode is enabled
+      that PWM channel.
+
+    $ref: /schemas/types.yaml#/definitions/uint16
+    default: 0
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - "#pwm-cells"
+
+additionalProperties: false
+
+examples:
+  - |
+    #include "dt-bindings/clock/microchip,mpfs-clock.h"
+    pwm@41000000 {
+      compatible = "microchip,corepwm-rtl-v4";
+      microchip,sync-update = /bits/ 16 <0>;
+      clocks = <&clkcfg CLK_FIC3>;
+      reg = <0x41000000 0xF0>;
+      #pwm-cells = <2>;
+    };