On Wed, Feb 12, 2025 at 03:16:16PM -0300, Jonathan Santos wrote:
> 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.
>
> Add a new trigger-sources property to enable synchronization over SPI
> and future multiple devices support. This property references the
> main device (or trigger provider) responsible for generating the
> SYNC_OUT pulse to drive the SYNC_IN of device.
>
> While at it, add description to the interrupts property.
>
> Signed-off-by: Jonathan Santos <Jonathan.Santos@xxxxxxxxxx>
> ---
> v3 Changes:
> * Fixed dt-bindings errors.
> * Trigger-source is set as an alternative to sync-in-gpios, so we
> don't break the previous ABI.
> * increased maxItems from trigger-sources to 2.
>
> 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 | 28 +++++++++++++++++--
> 1 file changed, 25 insertions(+), 3 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..4bcc9e20fab9 100644
> --- a/Documentation/devicetree/bindings/iio/adc/adi,ad7768-1.yaml
> +++ b/Documentation/devicetree/bindings/iio/adc/adi,ad7768-1.yaml
> @@ -26,7 +26,19 @@ properties:
> clock-names:
> const: mclk
>
> + trigger-sources:
> + description:
> + Specifies the device responsible for driving the synchronization pin,
> + as an alternative to adi,sync-in-gpios. If the own device node is
> + referenced, The synchronization over SPI is enabled and the SYNC_OUT
> + output will drive the SYNC_IN pin.
Maybe a silly question, but why is self-reference needed here?
sync-in-gpios is a required property at present, so why can't you
operate under the assumption that neither the trigger-sources when
neither are present? Is it because only one of the sources could be
external and one internal, or there could be either one or two internal
sources? Self-referencing properties always feel like a bit of a
mistake.
> + maxItems: 2
> +
> 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':
> @@ -57,6 +69,9 @@ properties:
> "#io-channel-cells":
> const: 1
>
> + "#trigger-source-cells":
> + const: 0
> +
> required:
> - compatible
> - reg
> @@ -65,7 +80,6 @@ required:
> - vref-supply
> - spi-cpol
> - spi-cpha
> - - adi,sync-in-gpios
>
> patternProperties:
> "^channel@([0-9]|1[0-5])$":
> @@ -89,6 +103,13 @@ patternProperties:
> allOf:
> - $ref: /schemas/spi/spi-peripheral-props.yaml#
>
> + - oneOf:
> + - required:
> + - trigger-sources
> + - "#trigger-source-cells"
> + - required:
> + - adi,sync-in-gpios
> +
> unevaluatedProperties: false
>
> examples:
> @@ -99,7 +120,7 @@ examples:
> #address-cells = <1>;
> #size-cells = <0>;
>
> - adc@0 {
> + adc0: adc@0 {
> compatible = "adi,ad7768-1";
> reg = <0>;
> spi-max-frequency = <2000000>;
> @@ -108,7 +129,8 @@ examples:
> vref-supply = <&adc_vref>;
> interrupts = <25 IRQ_TYPE_EDGE_RISING>;
> interrupt-parent = <&gpio>;
> - adi,sync-in-gpios = <&gpio 22 GPIO_ACTIVE_LOW>;
> + trigger-sources = <&adc0 0>;
> + #trigger-source-cells = <0>;
> reset-gpios = <&gpio 27 GPIO_ACTIVE_LOW>;
> clocks = <&ad7768_mclk>;
> clock-names = "mclk";
> --
> 2.34.1
>
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