[RFC v2 03/11] dt-bindings: iio: stm32-dfsdm-adc: add scaling support

27 Jul 2023

Add scaling support to STM32 DFSDM.
This introduces the following changes:
- Add ADC generic channel binding and remove support of deprecated
channel bindings.
- DFSDM is now implemented as a channel provider, so remove io-channels
properties.
- Add iio-backend property to connect DFSDM to an SD modulator.
Signed-off-by: Olivier Moysan olivier.moysan@foss.st.com
---
 .../bindings/iio/adc/st,stm32-dfsdm-adc.yaml  | 189 ++++++------------
 1 file changed, 63 insertions(+), 126 deletions(-)

diff --git a/Documentation/devicetree/bindings/iio/adc/st,stm32-dfsdm-adc.yaml b/Documentation/devicetree/bindings/iio/adc/st,stm32-dfsdm-adc.yaml
index 1970503389aa..128545cedc7f 100644
--- a/Documentation/devicetree/bindings/iio/adc/st,stm32-dfsdm-adc.yaml
+++ b/Documentation/devicetree/bindings/iio/adc/st,stm32-dfsdm-adc.yaml
@@ -85,22 +85,14 @@ patternProperties:
         description: Specifies the DFSDM filter instance used.
         maxItems: 1
-      interrupts:
-        maxItems: 1
+      '#address-cells':
+        const: 1
-      st,adc-channels:
-        description: |
-          List of single-ended channels muxed for this ADC.
-          On stm32h7 and stm32mp1:
-          - For st,stm32-dfsdm-adc: up to 8 channels numbered from 0 to 7.
-          - For st,stm32-dfsdm-dmic: 1 channel numbered from 0 to 7.
-        $ref: /schemas/types.yaml#/definitions/uint32-array
-        items:
-          minimum: 0
-          maximum: 7
+      '#size-cells':
+        const: 0
-      st,adc-channel-names:
-        description: List of single-ended channel names.
+      interrupts:
+        maxItems: 1
st,filter-order:
         description: |
@@ -111,39 +103,6 @@ patternProperties:
         $ref: /schemas/types.yaml#/definitions/uint32
         maximum: 5
-      "#io-channel-cells":
-        const: 1
-
-      st,adc-channel-types:
-        description: |
-          Single-ended channel input type.
-          - "SPI_R": SPI with data on rising edge (default)
-          - "SPI_F": SPI with data on falling edge
-          - "MANCH_R": manchester codec, rising edge = logic 0, falling edge = logic 1
-          - "MANCH_F": manchester codec, rising edge = logic 1, falling edge = logic 0
-        items:
-          enum: [ SPI_R, SPI_F, MANCH_R, MANCH_F ]
-        $ref: /schemas/types.yaml#/definitions/non-unique-string-array
-
-      st,adc-channel-clk-src:
-        description: |
-          Conversion clock source.
-          - "CLKIN": external SPI clock (CLKIN x)
-          - "CLKOUT": internal SPI clock (CLKOUT) (default)
-          - "CLKOUT_F": internal SPI clock divided by 2 (falling edge).
-          - "CLKOUT_R": internal SPI clock divided by 2 (rising edge).
-        items:
-          enum: [ CLKIN, CLKOUT, CLKOUT_F, CLKOUT_R ]
-        $ref: /schemas/types.yaml#/definitions/non-unique-string-array
-
-      st,adc-alt-channel:
-        description:
-          Must be defined if two sigma delta modulators are
-          connected on same SPI input.
-          If not set, channel n is connected to SPI input n.
-          If set, channel n is connected to SPI input n + 1.
-        type: boolean
-
       st,filter0-sync:
         description:
           Set to 1 to synchronize with DFSDM filter instance 0.
@@ -157,14 +116,68 @@ patternProperties:
         items:
           - const: rx
+    patternProperties:
+      "^channel@([0-9]|1[0-9])$":
+        type: object
+        $ref: "adc.yaml"
+        description: Represents the external channels which are connected to the DFSDM.
+
+        properties:
+          reg:
+            items:
+              minimum: 0
+              maximum: 19
+
+          label:
+            description: |
+              Unique name to identify channel.
+
+          st,adc-channel-types:
+            description: |
+              Single-ended channel input type.
+              - "SPI_R": SPI with data on rising edge (default)
+              - "SPI_F": SPI with data on falling edge
+              - "MANCH_R": manchester codec, rising edge = logic 0, falling edge = logic 1
+              - "MANCH_F": manchester codec, rising edge = logic 1, falling edge = logic 0
+            items:
+              enum: [ SPI_R, SPI_F, MANCH_R, MANCH_F ]
+            $ref: /schemas/types.yaml#/definitions/non-unique-string-array
+
+          st,adc-channel-clk-src:
+            description: |
+              Conversion clock source.
+              - "CLKIN": external SPI clock (CLKIN x)
+              - "CLKOUT": internal SPI clock (CLKOUT) (default)
+              - "CLKOUT_F": internal SPI clock divided by 2 (falling edge).
+              - "CLKOUT_R": internal SPI clock divided by 2 (rising edge).
+            items:
+              enum: [ CLKIN, CLKOUT, CLKOUT_F, CLKOUT_R ]
+            $ref: /schemas/types.yaml#/definitions/non-unique-string-array
+
+          st,adc-alt-channel:
+            description:
+              Must be defined if two sigma delta modulators are
+              connected on same SPI input.
+              If not set, channel n is connected to SPI input n.
+              If set, channel n is connected to SPI input n + 1.
+            type: boolean
+
+          io-backends:
+            description: |
+              phandle to an external sigma delta modulator or internal ADC output.
+            $ref: /schemas/types.yaml#/definitions/phandle
+
+        required:
+          - reg
+          - io-backends
+
+        additionalProperties: false
+
     required:
       - compatible
       - reg
       - interrupts
-      - st,adc-channels
-      - st,adc-channel-names
       - st,filter-order
-      - "#io-channel-cells"
allOf:
       - if:
@@ -175,14 +188,6 @@ patternProperties:
then:
           properties:
-            st,adc-channels:
-              minItems: 1
-              maxItems: 8
-
-            st,adc-channel-names:
-              minItems: 1
-              maxItems: 8
-
             st,adc-channel-types:
               minItems: 1
               maxItems: 8
@@ -191,14 +196,6 @@ patternProperties:
               minItems: 1
               maxItems: 8
-            io-channels:
-              description:
-                From common IIO binding. Used to pipe external sigma delta
-                modulator or internal ADC output to DFSDM channel.
-
-          required:
-            - io-channels
-
       - if:
           properties:
             compatible:
@@ -207,12 +204,6 @@ patternProperties:
then:
           properties:
-            st,adc-channels:
-              maxItems: 1
-
-            st,adc-channel-names:
-              maxItems: 1
-
             st,adc-channel-types:
               maxItems: 1
@@ -237,15 +228,9 @@ patternProperties:
                 "#sound-dai-cells":
                   const: 0
-                io-channels:
-                  description:
-                    From common IIO binding. Used to pipe external sigma delta
-                    modulator or internal ADC output to DFSDM channel.
-
               required:
                 - compatible
                 - "#sound-dai-cells"
-                - io-channels
allOf:
   - if:
@@ -278,52 +263,4 @@ allOf:
                 minimum: 0
                 maximum: 5
-examples:
-  - |
-    #include <dt-bindings/interrupt-controller/arm-gic.h>
-    #include <dt-bindings/clock/stm32mp1-clks.h>
-    dfsdm: dfsdm@4400d000 {
-      compatible = "st,stm32mp1-dfsdm";
-      reg = <0x4400d000 0x800>;
-      clocks = <&rcc DFSDM_K>, <&rcc ADFSDM_K>;
-      clock-names = "dfsdm", "audio";
-      #address-cells = <1>;
-      #size-cells = <0>;
-
-      dfsdm0: filter@0 {
-        compatible = "st,stm32-dfsdm-dmic";
-        reg = <0>;
-        interrupts = <GIC_SPI 110 IRQ_TYPE_LEVEL_HIGH>;
-        dmas = <&dmamux1 101 0x400 0x01>;
-        dma-names = "rx";
-        #io-channel-cells = <1>;
-        st,adc-channels = <1>;
-        st,adc-channel-names = "dmic0";
-        st,adc-channel-types = "SPI_R";
-        st,adc-channel-clk-src = "CLKOUT";
-        st,filter-order = <5>;
-
-        asoc_pdm0: dfsdm-dai {
-          compatible = "st,stm32h7-dfsdm-dai";
-          #sound-dai-cells = <0>;
-          io-channels = <&dfsdm0 0>;
-        };
-      };
-
-      dfsdm_pdm1: filter@1 {
-        compatible = "st,stm32-dfsdm-adc";
-        reg = <1>;
-        interrupts = <GIC_SPI 111 IRQ_TYPE_LEVEL_HIGH>;
-        dmas = <&dmamux1 102 0x400 0x01>;
-        dma-names = "rx";
-        #io-channel-cells = <1>;
-        st,adc-channels = <2 3>;
-        st,adc-channel-names = "in2", "in3";
-        st,adc-channel-types = "SPI_R", "SPI_R";
-        st,adc-channel-clk-src = "CLKOUT_F", "CLKOUT_F";
-        io-channels = <&sd_adc2 &sd_adc3>;
-        st,filter-order = <1>;
-      };
-    };
-
 ...
-- 
2.25.1


    