[PATCH 2/8] dt-bindings: iio: adc: ad7606: Add iio backend bindings

Guillaume Stols
2024-08-15T12:12:07Z

Add the required properties for iio-backend support, as well as an
example and the conditions to mutually exclude interruption and
conversion trigger with iio-backend.
The iio-backend's function is to controls the communication, and thus the
interruption pin won't be available anymore.
As a consequence, the conversion pin must be controlled externally since
we will miss information about when every single conversion cycle (i.e
conversion + data transfert) ends, hence a PWM is introduced to trigger
the conversions.

Signed-off-by: Guillaume Stols <gstols@baylibre.com>
---
.../devicetree/bindings/iio/adc/adi,ad7606.yaml | 75 +++++++++++++++++++++-
1 file changed, 72 insertions(+), 3 deletions(-)

diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad7606.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad7606.yaml
index c0008d36320f..4b324f7e3207 100644
--- a/Documentation/devicetree/bindings/iio/adc/adi,ad7606.yaml
+++ b/Documentation/devicetree/bindings/iio/adc/adi,ad7606.yaml
@@ -114,13 +114,28 @@ properties:
assumed that the pins are hardwired to VDD.
type: boolean

+ pwms:
+ description:
+ In case the conversion is triggered by a PWM instead of a GPIO plugged to
+ the CONVST pin, the PWM must be referenced.
+ minItems: 1
+ maxItems: 2
+
+ pwm-names:
+ minItems: 1
+ maxItems: 2
+
+ io-backends:
+ description:
+ A reference to the iio-backend, which is responsible handling the BUSY
+ pin's falling edge and communication.
+ An example of backend can be found at
+ http://analogdevicesinc.github.io/hdl/library/axi_ad7606x/index.html
+
required:
- compatible
- - reg
- avcc-supply
- vdrive-supply
- - interrupts
- - adi,conversion-start-gpios

# This checks if reg is a chipselect so the device is on an SPI
# bus, the if-clause will fail if reg is a tuple such as for a
@@ -137,6 +152,35 @@ then:
- spi-cpol

allOf:
+ # Communication is handled either by the backend or an interrupt.
+ - if:
+ properties:
+ pwms: false
+ then:
+ required:
+ - adi,conversion-start-gpios
+
+ - if:
+ properties:
+ adi,conversion-start-gpios: false
+ then:
+ required:
+ - pwms
+
+ - if:
+ properties:
+ interrupts: false
+ then:
+ required:
+ - io-backends
+
+ - if:
+ properties:
+ io-backends: false
+ then:
+ required:
+ - interrupts
+
- if:
properties:
compatible:
@@ -178,12 +222,37 @@ allOf:
adi,sw-mode: false
else:
properties:
+ pwms:
+ maxItems: 1
+ pwm-names:
+ maxItems: 1
adi,conversion-start-gpios:
maxItems: 1

unevaluatedProperties: false

examples:
+ - |
+ #include <dt-bindings/gpio/gpio.h>
+ / {
+ adi_adc {
+ compatible = "adi,ad7606b";
+
+ pwms = <&axi_pwm_gen 0 0>;
+
+ avcc-supply = <&adc_vref>;
+ vdrive-supply = <&vdd_supply>;
+
+ reset-gpios = <&gpio0 91 GPIO_ACTIVE_HIGH>;
+ standby-gpios = <&gpio0 90 GPIO_ACTIVE_LOW>;
+ adi,range-gpios = <&gpio0 89 GPIO_ACTIVE_HIGH>;
+ adi,oversampling-ratio-gpios = <&gpio0 88 GPIO_ACTIVE_HIGH
+ &gpio0 87 GPIO_ACTIVE_HIGH
+ &gpio0 86 GPIO_ACTIVE_HIGH>;
+ io-backends = <&iio_backend>;
+ };
+ };
+
- |
#include <dt-bindings/gpio/gpio.h>
#include <dt-bindings/interrupt-controller/irq.h>

--
2.34.1