[PATCH v3 03/10] dt-bindings: iio: adc: ad7606: Add iio backend bindings

Guillaume Stols
2024-10-04T21:48:51Z

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 transfer) 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 | 64 +++++++++++++++++++++-
1 file changed, 62 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad7606.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad7606.yaml
index 47081c79a1cf..a389cfda824d 100644
--- a/Documentation/devicetree/bindings/iio/adc/adi,ad7606.yaml
+++ b/Documentation/devicetree/bindings/iio/adc/adi,ad7606.yaml
@@ -129,6 +129,29 @@ 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.
+ The first is the PWM connected to CONVST or CONVST1 for the chips with 2
+ PWM connected to CONVST2 if CONVST2 is available and not shorted to
+ CONVST1.
+ minItems: 1
+ maxItems: 2
+
+ pwm-names:
+ items:
+ - const: convst1
+ - const: convst2
+
+ 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
+
+
patternProperties:
"^channel@[1-8]$":
type: object
@@ -175,12 +198,22 @@ required:
- reg
- avcc-supply
- vdrive-supply
- - interrupts
- - adi,conversion-start-gpios

allOf:
- $ref: /schemas/spi/spi-peripheral-props.yaml#

+ - oneOf:
+ - required:
+ - adi,conversion-start-gpios
+ - required:
+ - pwms
+
+ - oneOf:
+ - required:
+ - interrupts
+ - required:
+ - io-backends
+
- if:
properties:
compatible:
@@ -222,6 +255,10 @@ allOf:
adi,sw-mode: false
else:
properties:
+ pwms:
+ maxItems: 1
+ pwm-names:
+ maxItems: 1
adi,conversion-start-gpios:
maxItems: 1

@@ -247,6 +284,29 @@ allOf:
unevaluatedProperties: false

examples:
+ - |
+ #include <dt-bindings/gpio/gpio.h>
+ iio-backend {
+ #address-cells = <1>;
+ #size-cells = <0>;
+ adi_adc@0 {
+ compatible = "adi,ad7606b";
+ reg = <0>;
+ 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