boards/shields: Add x_nucleo_cca02m1 microphone shield

Provide definition files and simple documentation for x-nucleo-cca02m1
microphone shield.

Signed-off-by: Armando Visconti <[email protected]>

Author: avisconti

boards/shields/x_nucleo_cca02m1/doc/img/x-nucleo-cca02m1.jpg

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+.. _x-nucleo-cca02m1:
+
+X-NUCLEO-CCA02M1: Digital MEMS microphones shield for STM32 Nucleo
+##################################################################
+
+Overview
+********
+The X-NUCLEO-CCA02M1 is an evaluation board based on digital MEMS microphones
+compatible with the ST morpho connector layout.
+It has two microphones soldered onto the board and is compatible with digital microphone
+coupon boards such as STEVAL-MKI129Vx and STEVAL-MKI155Vx.
+
+The X-NUCLEO-CCA02M1 allows synchronized acquisition and streaming of up to 4
+microphones through I2S, SPI or DFSDM peripherals.
+
+.. image:: img/x-nucleo-cca02m1.jpg
+     :width: 340px
+     :height: 410px
+     :align: center
+     :alt: X-NUCLEO-CCA02M1
+
+For more information about the board, see the `X-NUCLEO-CCA02M1 website`_
+
+Hardware
+********
+
+X-NUCLEO-CCA02M1 provides the following key features:
+
+ - 2 x MP34DT01 on-board microphones
+ - 4 x header (3x2) to connect up to 4 external microphones
+ - Equipped with ST morpho connector
+ - Equipped with Arduino UNO R3 connector
+ - RoHS compliant
+
+
+For more information about this shield, see the `X-NUCLEO-CCA02M1 data brief`_
+
+Programming
+***********
+
+The X-NUCLEO-CCA02M1 can be connected to the SoC through I2S, SPI, or DFSDM peripherals,
+but only I2S has been tested in Zephyr using a nucleo_f411re board.
+
+References
+**********
+
+.. target-notes::
+
+.. _X-NUCLEO-CCA02M1 website:
+   https://www.st.com/en/ecosystems/x-nucleo-cca02m1.html
+
+.. _X-NUCLEO-CCA02M1 data brief:
+   https://www.st.com/resource/en/data_brief/x-nucleo-cca02m1.pdf
+

boards/shields/x_nucleo_cca02m1/doc/index.rst

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+/*
+ * Copyright (c) 2019 STMicroelectronics
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+&arduino_i2s {
+	mp34dt01@0 {
+		compatible = "st,mpxxdtyy";
+		reg = <0>;
+		label = "MP34DT01";
+	};
+
+	mp34dt01@1 {
+		compatible = "st,mpxxdtyy";
+		reg = <1>;
+		label = "MP34DT01";
+	};
+};