diff mbox series

[v6,5/9] dt-bindings: iio: add backend support to sd modulator

Message ID 20240730084640.1307938-6-olivier.moysan@foss.st.com
State Not Applicable
Headers show
Series iio: adc: dfsdm: add scaling support | expand

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Commit Message

Olivier Moysan July 30, 2024, 8:46 a.m. UTC
The legacy sd modulator driver registers the sigma delta modulator as
an IIO channel provider. This implementation is not convenient when the
SD modulator has to be cascaded with another IIO device. The scaling
information is distributed across devices, which makes it difficult to
report consistent scaling data on IIO devices.

The solution is to expose these cascaded IIO devices as an aggregate
device, which report global scaling information.
Add IIO backend support to SD modulator to allow scaling information
management.

Signed-off-by: Olivier Moysan <olivier.moysan@foss.st.com>
---
 .../iio/adc/sigma-delta-modulator.yaml         | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

Comments

Rob Herring Aug. 6, 2024, 2:49 p.m. UTC | #1
On Tue, 30 Jul 2024 10:46:35 +0200, Olivier Moysan wrote:
> The legacy sd modulator driver registers the sigma delta modulator as
> an IIO channel provider. This implementation is not convenient when the
> SD modulator has to be cascaded with another IIO device. The scaling
> information is distributed across devices, which makes it difficult to
> report consistent scaling data on IIO devices.
> 
> The solution is to expose these cascaded IIO devices as an aggregate
> device, which report global scaling information.
> Add IIO backend support to SD modulator to allow scaling information
> management.
> 
> Signed-off-by: Olivier Moysan <olivier.moysan@foss.st.com>
> ---
>  .../iio/adc/sigma-delta-modulator.yaml         | 18 ++++++++++++++++--
>  1 file changed, 16 insertions(+), 2 deletions(-)
> 

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/iio/adc/sigma-delta-modulator.yaml b/Documentation/devicetree/bindings/iio/adc/sigma-delta-modulator.yaml
index cab0d425eaa4..7d33c4e09905 100644
--- a/Documentation/devicetree/bindings/iio/adc/sigma-delta-modulator.yaml
+++ b/Documentation/devicetree/bindings/iio/adc/sigma-delta-modulator.yaml
@@ -18,18 +18,32 @@  properties:
       - sd-modulator
       - ads1201
 
+  '#io-backend-cells':
+    const: 0
+
   '#io-channel-cells':
     const: 0
 
 required:
   - compatible
-  - '#io-channel-cells'
+
+anyOf:
+  - required: ['#io-backend-cells']
+  - required: ['#io-channel-cells']
 
 additionalProperties: false
 
 examples:
   - |
-    ads1202: adc {
+    // Backend binding example. SD modulator configured as an IIO backend device
+    ads1201_0: adc {
+      compatible = "sd-modulator";
+      #io-backend-cells = <0>;
+    };
+
+  - |
+    // Legacy binding example. SD modulator configured as an IIO channel provider
+    ads1201_1: adc {
       compatible = "sd-modulator";
       #io-channel-cells = <0>;
     };