On 01/12, Jonathan Cameron wrote: > On Fri, 10 Jan 2025 18:51:06 -0300 > Marcelo Schmitt <marcelo.schmitt1@xxxxxxxxx> wrote: > > > On 01/07, Jonathan Santos wrote: > > > Add adi,sync-in-spi property to enable synchronization over SPI. > > > This should be used in the case when the GPIO cannot provide a > > > pulse synchronous with the base MCLK signal. > > > > > > User can choose between SPI, GPIO synchronization or neither of them, > > > but only if a external pulse can be provided, for example, by another > > > device in a multidevice setup. > > > > > > Signed-off-by: Jonathan Santos <Jonathan.Santos@xxxxxxxxxx> > > > --- > > > .../bindings/iio/adc/adi,ad7768-1.yaml | 24 ++++++++++++++++++- > > > 1 file changed, 23 insertions(+), 1 deletion(-) > > > > > > diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad7768-1.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad7768-1.yaml > > > index 3ce59d4d065f..55cec27bfe60 100644 > > > --- a/Documentation/devicetree/bindings/iio/adc/adi,ad7768-1.yaml > > > +++ b/Documentation/devicetree/bindings/iio/adc/adi,ad7768-1.yaml > > > @@ -47,6 +47,15 @@ properties: > > > in any way, for example if the filter decimation rate changes. > > > As the line is active low, it should be marked GPIO_ACTIVE_LOW. > > > > > > + adi,sync-in-spi: > > > + description: > > > + Enables synchronization of multiple devices over SPI. This property is > > > + used when a signal synchronous to the base MCLK signal cannot be provided > > > + via GPIO. It requires the SYNC_OUT pin to be connected to the SYNC_IN pin > > > + on the ADC. In the case of multiple devices, the SYNC_OUT pin of one device > > > + should be routed to the SYNC_IN pins of the other devices. > > So, if I'm getting it right, > > Datasheet on this is indeed complex! > > >/SYNC_IN may be driven by a GPIO (ADAQ7768-1 datasheet Figure 131), > > For that we expose a gpio binding already. If that's present we know what is going on. > > >/SYNC_IN may be driven by own device /SYNC_OUT (ADAQ7768-1 datasheet Figure 133), > > This is the default - no information provided so it isn't wired externally. > We don't normally bother to describe required chip to chip connections. > I couldn't entirely figure out if this is 'required' if we aren't driving explicitly > from GPIO or another chip but i think it is(?). > It is. If the device is not being driven by a GPIO or an external device, the user should connect the /SYNC_OUT to /SYNC_IN. We could assume that this is the case if the GPIO is not present in the devicetree, maybe put that into the description. The sync-out-sync-in property as a boolean can be quite redundant, since we also need to remove the GPIO. > >/SYNC_IN may be driven by other AD7768-1 > /SYNC_OUT pin (also Figure 133). > This is only case we are about for sync in I think. > > As long as there isn't a valid 'not connected' It think we are fine with a boolean. > If opt for a single node instace, thats ok; otherwise, David's trigger-sources suggestion seems to be the best approach. > > That is too much to describe with a boolean. > > > > If David's suggestion of using a trigger-source doesn't fit, this property > > should at least become an enum or string. > > > > > + type: boolean > > > + > > > reset-gpios: > > > maxItems: 1 > > > > > > @@ -65,7 +74,6 @@ required: > > > - vref-supply > > > - spi-cpol > > > - spi-cpha > > > - - adi,sync-in-gpios > > > > > > patternProperties: > > > "^channel@([0-9]|1[0-5])$": > > > @@ -89,6 +97,20 @@ patternProperties: > > > allOf: > > > - $ref: /schemas/spi/spi-peripheral-props.yaml# > > > > > > + # adi,sync-in-gpios and adi,sync-in-spi are mutually exclusive (neither is also valid) > > > + - if: > > > + required: > > > + - adi,sync-in-gpios > > > + then: > > > + properties: > > > + adi,sync-in-spi: false > > > + - if: > > > + required: > > > + - adi,sync-in-spi > > > + then: > > > + properties: > > > + adi,sync-in-gpios: false > > > + > > > unevaluatedProperties: false > > > > > > examples: > > > -- > > > 2.34.1 > > > >
