[PATCH v6 03/10] dt-bindings: iio: adc: adi,ad7{124,173,192,780}: Allow specifications of a gpio for irq line

Uwe Kleine-König
2024-12-06T17:29:18Z

For the AD7124 chip and some of its cousins the logical irq line (R̅D̅Y̅)
is physically on the same pin as the spi MISO output (DOUT) and so
reading a register might trigger an interrupt. For correct operation
it's critical that the actual state of the pin can be read to judge if
an interrupt event is a real one or just a spurious one triggered by
toggling the line in its MISO mode.

Allow specification of an "rdy-gpios" property that references a GPIO
that can be used for that purpose. While this is typically the same GPIO
also used (implicitly) as interrupt source, it is still supposed that
the interrupt is specified as before and usual.

Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
---
.../devicetree/bindings/iio/adc/adi,ad7124.yaml | 13 +++++++++++++
.../devicetree/bindings/iio/adc/adi,ad7173.yaml | 12 ++++++++++++
.../devicetree/bindings/iio/adc/adi,ad7192.yaml | 15 +++++++++++++++
.../devicetree/bindings/iio/adc/adi,ad7780.yaml | 11 +++++++++++
4 files changed, 51 insertions(+)

diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad7124.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad7124.yaml
index 35ed04350e28..7146a654ae38 100644
--- a/Documentation/devicetree/bindings/iio/adc/adi,ad7124.yaml
+++ b/Documentation/devicetree/bindings/iio/adc/adi,ad7124.yaml
@@ -37,6 +37,17 @@ properties:
description: IRQ line for the ADC
maxItems: 1

+ rdy-gpios:
+ description:
+ GPIO reading the R̅D̅Y̅ line. Having such a GPIO is technically optional but
+ highly recommended because DOUT/R̅D̅Y̅ toggles during SPI transfers (in its
+ DOUT aka MISO role) and so usually triggers a spurious interrupt. The
+ distinction between such a spurious event and a real one can only be done
+ by reading such a GPIO. (There is a register telling the same
+ information, but accessing that one needs a SPI transfer which then
+ triggers another interrupt event.)
+ maxItems: 1
+
'#address-cells':
const: 1

@@ -111,6 +122,7 @@ unevaluatedProperties: false

examples:
- |
+ #include <dt-bindings/gpio/gpio.h>
spi {
#address-cells = <1>;
#size-cells = <0>;
@@ -121,6 +133,7 @@ examples:
spi-max-frequency = <5000000>;
interrupts = <25 2>;
interrupt-parent = <&gpio>;
+ rdy-gpios = <&gpio 25 GPIO_ACTIVE_LOW>;
refin1-supply = <&adc_vref>;
clocks = <&ad7124_mclk>;
clock-names = "mclk";
diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad7173.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad7173.yaml
index ad15cf9bc2ff..21ee319d4675 100644
--- a/Documentation/devicetree/bindings/iio/adc/adi,ad7173.yaml
+++ b/Documentation/devicetree/bindings/iio/adc/adi,ad7173.yaml
@@ -135,6 +135,17 @@ properties:
'#clock-cells':
const: 0

+ rdy-gpios:
+ description:
+ GPIO reading the R̅D̅Y̅ line. Having such a GPIO is technically optional but
+ highly recommended because DOUT/R̅D̅Y̅ toggles during SPI transfers (in its
+ DOUT aka MISO role) and so usually triggers a spurious interrupt. The
+ distinction between such a spurious event and a real one can only be done
+ by reading such a GPIO. (There is a register telling the same
+ information, but accessing that one needs a SPI transfer which then
+ triggers another interrupt event.)
+ maxItems: 1
+
patternProperties:
"^channel@[0-9a-f]$":
type: object
@@ -443,6 +454,7 @@ examples:
interrupts = <25 IRQ_TYPE_EDGE_FALLING>;
interrupt-names = "rdy";
interrupt-parent = <&gpio>;
+ rdy-gpios = <&gpio 25 GPIO_ACTIVE_LOW>;
spi-max-frequency = <5000000>;
gpio-controller;
#gpio-cells = <2>;
diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad7192.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad7192.yaml
index 66dd1c549bd3..0bd2c6906c83 100644
--- a/Documentation/devicetree/bindings/iio/adc/adi,ad7192.yaml
+++ b/Documentation/devicetree/bindings/iio/adc/adi,ad7192.yaml
@@ -106,6 +106,17 @@ properties:
description: see Documentation/devicetree/bindings/iio/adc/adc.yaml
type: boolean

+ rdy-gpios:
+ description:
+ GPIO reading the R̅D̅Y̅ line. Having such a GPIO is technically optional but
+ highly recommended because DOUT/R̅D̅Y̅ toggles during SPI transfers (in its
+ DOUT aka MISO role) and so usually triggers a spurious interrupt. The
+ distinction between such a spurious event and a real one can only be done
+ by reading such a GPIO. (There is a register telling the same
+ information, but accessing that one needs a SPI transfer which then
+ triggers another interrupt event.)
+ maxItems: 1
+
patternProperties:
"^channel@[0-9a-f]+$":
type: object
@@ -181,6 +192,7 @@ unevaluatedProperties: false

examples:
- |
+ #include <dt-bindings/gpio/gpio.h>
spi {
#address-cells = <1>;
#size-cells = <0>;
@@ -195,6 +207,7 @@ examples:
clock-names = "mclk";
interrupts = <25 0x2>;
interrupt-parent = <&gpio>;
+ rdy-gpios = <&gpio 25 GPIO_ACTIVE_LOW>;
aincom-supply = <&aincom>;
dvdd-supply = <&dvdd>;
avdd-supply = <&avdd>;
@@ -207,6 +220,7 @@ examples:
};
};
- |
+ #include <dt-bindings/gpio/gpio.h>
spi {
#address-cells = <1>;
#size-cells = <0>;
@@ -224,6 +238,7 @@ examples:
#clock-cells = <0>;
interrupts = <25 0x2>;
interrupt-parent = <&gpio>;
+ rdy-gpios = <&gpio 25 GPIO_ACTIVE_LOW>;
aincom-supply = <&aincom>;
dvdd-supply = <&dvdd>;
avdd-supply = <&avdd>;
diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad7780.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad7780.yaml
index be2616ff9af6..5c8df45bfab0 100644
--- a/Documentation/devicetree/bindings/iio/adc/adi,ad7780.yaml
+++ b/Documentation/devicetree/bindings/iio/adc/adi,ad7780.yaml
@@ -63,6 +63,17 @@ properties:
marked GPIO_ACTIVE_LOW.
maxItems: 1

+ rdy-gpios:
+ description:
+ GPIO reading the R̅D̅Y̅ line. Having such a GPIO is technically optional but
+ highly recommended because DOUT/R̅D̅Y̅ toggles during SPI transfers (in its
+ DOUT aka MISO role) and so usually triggers a spurious interrupt. The
+ distinction between such a spurious event and a real one can only be done
+ by reading such a GPIO. (There is a register telling the same
+ information, but accessing that one needs a SPI transfer which then
+ triggers another interrupt event.)
+ maxItems: 1
+
required:
- compatible
- reg
--
2.45.2