[v10,1/3] dt-bindings: pwm: Add binding for Allwinner D1/T113-S3/R329 PWM controller

Commit Message

Александр Шубин Oct. 11, 2024, 10:27 a.m. UTC

Allwinner's D1, T113-S3 and R329 SoCs have a new pwm
controller witch is different from the previous pwm-sun4i.

The D1 and T113 are identical in terms of peripherals,
they differ only in the architecture of the CPU core, and
even share the majority of their DT. Because of that,
using the same compatible makes sense.
The R329 is a different SoC though, and should have
a different compatible string added, especially as there
is a difference in the number of channels.

D1 and T113s SoCs have one PWM controller with 8 channels.
R329 SoC has two PWM controllers in both power domains, one of
them has 9 channels (CPUX one) and the other has 6 (CPUS one).

Add a device tree binding for them.

Signed-off-by: Aleksandr Shubin <[e-mail]>
Reviewed-by: Conor Dooley <[e-mail]>
---
 .../bindings/pwm/allwinner,sun20i-pwm.yaml    | 84 +++++++++++++++++++
 1 file changed, 84 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/pwm/allwinner,sun20i-pwm.yaml

Comments

Uwe Kleine-König Oct. 29, 2024, 8:56 a.m. UTC | #1

Hello,

On Fri, Oct 11, 2024 at 01:27:32PM +0300, Aleksandr Shubin wrote:
> +  allwinner,pwm-channels:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description: The number of PWM channels configured for this instance
> +    enum: [6, 9]

I wonder if the number of channels is a property common enough that we
can use "num-pwm-channels" here instead of a vendor specific property.
Or would you suggest a different name? gpio-controller nodes have
"ngpios", so maybe "npwms"?

A quick grep suggests we already have:

	fsl,pwm-number in mxs-pwm.yaml
	st,pwm-num-chan in pwm-st.txt
	snps,pwm-number in snps,dw-apb-timers-pwm2.yaml

As a follow up this could then be used by pwmchip_alloc() to determine
the number of channels if the passed npwm value is 0.

Best regards
Uwe

Александр Шубин Nov. 10, 2024, 11:16 a.m. UTC | #2

Hello Uwe,

I appreciate your suggestion to use a more standardized
property name like "pwm-number" instead of vendor-specific names.

Since the name "pwm-number" is present in two drivers,
we could consider using this name here as an option.
Or perhaps we should choose a new common name "npwms"
as you suggested?

Please let me know what you think about this.

Best regards,
Aleksandr.

вт, 29 окт. 2024 г. в 11:56, Uwe Kleine-König <[e-mail]>:
>
> Hello,
>
> On Fri, Oct 11, 2024 at 01:27:32PM +0300, Aleksandr Shubin wrote:
> > +  allwinner,pwm-channels:
> > +    $ref: /schemas/types.yaml#/definitions/uint32
> > +    description: The number of PWM channels configured for this instance
> > +    enum: [6, 9]
>
> I wonder if the number of channels is a property common enough that we
> can use "num-pwm-channels" here instead of a vendor specific property.
> Or would you suggest a different name? gpio-controller nodes have
> "ngpios", so maybe "npwms"?
>
> A quick grep suggests we already have:
>
>         fsl,pwm-number in mxs-pwm.yaml
>         st,pwm-num-chan in pwm-st.txt
>         snps,pwm-number in snps,dw-apb-timers-pwm2.yaml
>
> As a follow up this could then be used by pwmchip_alloc() to determine
> the number of channels if the passed npwm value is 0.
>
> Best regards
> Uwe

Patch

diff --git a/Documentation/devicetree/bindings/pwm/allwinner,sun20i-pwm.yaml b/Documentation/devicetree/bindings/pwm/allwinner,sun20i-pwm.yaml
new file mode 100644
index 000000000000..89cebf7841a6
--- /dev/null
+++ b/Documentation/devicetree/bindings/pwm/allwinner,sun20i-pwm.yaml
@@ -0,0 +1,84 @@ 
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pwm/allwinner,sun20i-pwm.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Allwinner D1, T113-S3 and R329 PWM
+
+maintainers:
+  - Aleksandr Shubin <[e-mail]>
+  - Brandon Cheo Fusi <[e-mail]>
+
+properties:
+  compatible:
+    oneOf:
+      - const: allwinner,sun20i-d1-pwm
+      - items:
+          - const: allwinner,sun50i-r329-pwm
+          - const: allwinner,sun20i-d1-pwm
+
+  reg:
+    maxItems: 1
+
+  "#pwm-cells":
+    const: 3
+
+  clocks:
+    items:
+      - description: Bus clock
+      - description: 24 MHz oscillator
+      - description: APB clock
+
+  clock-names:
+    items:
+      - const: bus
+      - const: hosc
+      - const: apb
+
+  resets:
+    maxItems: 1
+
+  allwinner,pwm-channels:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: The number of PWM channels configured for this instance
+    enum: [6, 9]
+
+allOf:
+  - $ref: pwm.yaml#
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: allwinner,sun50i-r329-pwm
+
+    then:
+      required:
+        - allwinner,pwm-channels
+
+unevaluatedProperties: false
+
+required:
+  - compatible
+  - reg
+  - "#pwm-cells"
+  - clocks
+  - clock-names
+  - resets
+
+examples:
+  - |
+    #include <dt-bindings/clock/sun20i-d1-ccu.h>
+    #include <dt-bindings/reset/sun20i-d1-ccu.h>
+
+    pwm: pwm@2000c00 {
+      compatible = "allwinner,sun20i-d1-pwm";
+      reg = <0x02000c00 0x400>;
+      clocks = <&ccu CLK_BUS_PWM>, <&dcxo>, <&ccu CLK_APB0>;
+      clock-names = "bus", "hosc", "apb";
+      resets = <&ccu RST_BUS_PWM>;
+      #pwm-cells = <0x3>;
+    };
+
+...