dt-bindings: iio: adc: at91-sama5d2_adc: add channel specific consumer info

Added defines for channel consumer device-tree binding

Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/adc/at91-sama5d2_adc.txt

@@ -21,6 +21,14 @@ Optional properties:
   - dmas: Phandle to dma channel for the ADC.
   - dma-names: Must be "rx" when dmas property is being used.
   See ../../dma/dma.txt for details.
+  - #io-channel-cells: in case consumer drivers are attached, this must be 1.
+  See <Documentation/devicetree/bindings/iio/iio-bindings.txt> for details.
+
+Properties for consumer drivers:
+  - Consumer drivers can be connected to this producer device, as specified
+  in <Documentation/devicetree/bindings/iio/iio-bindings.txt>
+  - Channels exposed are specified in:
+  <dt-bindings/iio/adc/at91-sama5d2_adc.txt>
 
 Example:
 
@@ -38,4 +46,5 @@ adc: adc@fc030000 {
 	atmel,trigger-edge-type = <IRQ_TYPE_EDGE_BOTH>;
 	dmas = <&dma0 (AT91_XDMAC_DT_MEM_IF(0) | AT91_XDMAC_DT_PER_IF(1) | AT91_XDMAC_DT_PERID(25))>;
 	dma-names = "rx";
+	#io-channel-cells = <1>;
 }

include/dt-bindings/iio/adc/at91-sama5d2_adc.h

@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * This header provides constants for configuring the AT91 SAMA5D2 ADC
+ */
+
+#ifndef _DT_BINDINGS_IIO_ADC_AT91_SAMA5D2_ADC_H
+#define _DT_BINDINGS_IIO_ADC_AT91_SAMA5D2_ADC_H
+
+/* X relative position channel index */
+#define AT91_SAMA5D2_ADC_X_CHANNEL		24
+/* Y relative position channel index */
+#define AT91_SAMA5D2_ADC_Y_CHANNEL		25
+/* pressure channel index */
+#define AT91_SAMA5D2_ADC_P_CHANNEL		26
+
+#endif