On 1/27/25 9:11 AM, Jonathan Santos wrote:
> Add a new trigger-sources property to enable synchronization across
> multiple devices. This property references the main device (or
> trigger provider) responsible for generating the pulse to drive the
> SYNC_IN of all devices in the setup.
>
> In addition to GPIO synchronization, The AD7768-1 also supports
> synchronization over SPI, which use is recommended when the GPIO
> cannot provide a pulse synchronous with the base MCLK signal. It
> consists of looping back the SYNC_OUT to the SYNC_IN pin and send
> a command via SPI to trigger the synchronization.
>
> SPI-based synchronization is enabled in the absence of adi,sync-in-gpios
> property. Since adi,sync-in-gpios is not long the only method, remove it
> from required properties.
>
> While at it, add description to the interrupt property.
>
> Signed-off-by: Jonathan Santos <Jonathan.Santos@xxxxxxxxxx>
> ---
> v2 Changes:
> * Patch added as replacement for adi,sync-in-spi patch.
> * addressed the request for a description to interrupts property.
> ---
> .../bindings/iio/adc/adi,ad7768-1.yaml | 22 +++++++++++++++++--
> 1 file changed, 20 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad7768-1.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad7768-1.yaml
> index 3ce59d4d065f..3e119cf1754b 100644
> --- a/Documentation/devicetree/bindings/iio/adc/adi,ad7768-1.yaml
> +++ b/Documentation/devicetree/bindings/iio/adc/adi,ad7768-1.yaml
> @@ -26,7 +26,17 @@ properties:
> clock-names:
> const: mclk
>
> + trigger-sources:
> + description:
> + References the main device responsible for synchronization. In a single
> + device setup, reference the own node.
> + maxItems: 1
We probably actually need 2 here. One for /SYNC_IN and one for a GPIO3 pin
acting as the /START signal.
> +
> interrupts:
> + description:
> + Specifies the interrupt line associated with the ADC. This refers
> + to the DRDY (Data Ready) pin, which signals when conversion results are
> + available.
> maxItems: 1
>
> '#address-cells':
> @@ -46,6 +56,8 @@ properties:
> sampling. A pulse is always required if the configuration is changed
> in any way, for example if the filter decimation rate changes.
> As the line is active low, it should be marked GPIO_ACTIVE_LOW.
> + In the absence of this property, Synchronization over SPI will be
> + enabled.
Isn't /SYNC_OUT connected to /SYNC_IN required for synchronization over SPI?
If yes, instead of adding this text, I would make the binding have:
oneOf:
- required:
- trigger-sources
- required:
- adi,sync-in-gpios
>
> reset-gpios:
> maxItems: 1
> @@ -57,6 +69,9 @@ properties:
> "#io-channel-cells":
> const: 1
>
> + "#trigger-source-cells":
> + const: 0
> +
> required:
> - compatible
> - reg
> @@ -65,7 +80,8 @@ required:
> - vref-supply
> - spi-cpol
> - spi-cpha
> - - adi,sync-in-gpios
> + - trigger-sources
> + - #trigger-source-cells
>
> patternProperties:
> "^channel@([0-9]|1[0-5])$":
> @@ -99,7 +115,7 @@ examples:
> #address-cells = <1>;
> #size-cells = <0>;
>
> - adc@0 {
> + adc0: adc@0 {
> compatible = "adi,ad7768-1";
> reg = <0>;
> spi-max-frequency = <2000000>;
> @@ -109,6 +125,8 @@ examples:
> interrupts = <25 IRQ_TYPE_EDGE_RISING>;
> interrupt-parent = <&gpio>;
> adi,sync-in-gpios = <&gpio 22 GPIO_ACTIVE_LOW>;
Don't we need to drop adi,sync-in-gpios here? I don't think we would have two
things connected to /SYNC_IN at the same time.
> + trigger-sources = <&adc0>;
> + #trigger-source-cells = <0>;
> reset-gpios = <&gpio 27 GPIO_ACTIVE_LOW>;
> clocks = <&ad7768_mclk>;
> clock-names = "mclk";
