[PATCH v3 08/10] dt-bindings: iio: adc: ad7476: Add ROHM bd79105

From: Matti Vaittinen
Date: Fri Aug 08 2025 - 04:58:03 EST

The ROHM BD79105 is a simple, 16-bit, 1-channel ADC with a 'CONVSTART'
pin used to start the ADC conversion. Other than the 'CONVSTART', there
are 3 supply pins (one used as a reference), analog inputs, ground and
communication pins. It's worth noting that the pin somewhat confusingly
labeled as 'DIN', is a pin which should be used as a chip-select. The IC
does not have any writable registers.

The device is designed so that the output pin can, in addition to
outputting the data, be used as a 'data-ready'-IRQ. This, however, would
require the IRQ to be masked from host side for the duration of the data
reads - and it wouldn't also work when the SPI is shared. (As access to
the other SPI devices would cause data line changes to be detected as
IRQs - and the BD79105 provides no means to detect if it has generated
an IRQ).

Hence the device-tree does not contain any IRQ properties.

Add a compatible for the bd79105.

Signed-off-by: Matti Vaittinen <mazziesaccount@xxxxxxxxx>

---
Revision history:
v2 => :
- No changes

v1 => v2:
- BD79105 can provide data-ready IRQ (or GPIO) via DOUT-pin.
---
.../bindings/iio/adc/adi,ad7476.yaml | 54 +++++++++++++++++++
1 file changed, 54 insertions(+)

diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad7476.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad7476.yaml
index d0cb32f136e5..c411a7467651 100644
--- a/Documentation/devicetree/bindings/iio/adc/adi,ad7476.yaml
+++ b/Documentation/devicetree/bindings/iio/adc/adi,ad7476.yaml
@@ -41,6 +41,7 @@ properties:
- adi,ad7910
- adi,ad7920
- adi,ad7940
+ - rohm,bd79105
- ti,adc081s
- ti,adc101s
- ti,adc121s
@@ -55,6 +56,11 @@ properties:
reg:
maxItems: 1

+ interrupts:
+ description:
+ The data-ready interrupt. Provided via DOUT pin.
+ maxItems: 1
+
vcc-supply:
description:
Main powersupply voltage for the chips, sometimes referred to as VDD on
@@ -75,6 +81,10 @@ properties:
description: A GPIO used to trigger the start of a conversion
maxItems: 1

+ rdy-gpios:
+ description: A GPIO for detecting the data-ready.
+ maxItems: 1
+
required:
- compatible
- reg
@@ -82,6 +92,20 @@ required:
allOf:
- $ref: /schemas/spi/spi-peripheral-props.yaml#

+# Devices with an IRQ
+ - if:
+ properties:
+ compatible:
+ contains:
+ enum:
+ - rohm,bd79105
+ then:
+ properties:
+ interrupts: true
+ else:
+ properties:
+ interrupts: false
+
# Devices where reference is vcc
- if:
properties:
@@ -115,6 +139,7 @@ allOf:
- adi,ad7274
- adi,ad7475
- lltc,ltc2314-14
+ - rohm,bd79105
then:
properties:
vref-supply: true
@@ -131,6 +156,7 @@ allOf:
- adi,ad7274
- adi,ad7475
- lltc,ltc2314-14
+ - rohm,bd79105
then:
required:
- vref-supply
@@ -141,12 +167,28 @@ allOf:
enum:
- adi,ad7475
- adi,ad7495
+ - rohm,bd79105
then:
properties:
vdrive-supply: true
else:
properties:
vdrive-supply: false
+
+ # Devices which support polling the data-ready via GPIO
+ - if:
+ properties:
+ compatible:
+ contains:
+ enum:
+ - rohm,bd79105
+ then:
+ properties:
+ rdy-gpios: true
+ else:
+ properties:
+ rdy-gpios: false
+
- if:
properties:
compatible:
@@ -154,6 +196,7 @@ allOf:
enum:
- adi,ad7091
- adi,ad7091r
+ - rohm,bd79105
then:
properties:
adi,conversion-start-gpios: true
@@ -161,6 +204,17 @@ allOf:
properties:
adi,conversion-start-gpios: false

+ # Devices with a convstart GPIO where it is not optional
+ - if:
+ properties:
+ compatible:
+ contains:
+ enum:
+ - rohm,bd79105
+ then:
+ required:
+ - adi,conversion-start-gpios
+
unevaluatedProperties: false

examples:
--
2.50.1

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