Add BVA CSI camera usage guide

boards/beagleplay/demos-and-tutorials/play-kernel-development.rst

 .. _play-kernel-development:
 
-.. toctree::
- :numbered:
-
-   Introduction
-
 Introduction
 #############
 

boards/beaglev/ahead/02-quick-start.rst

@@ -119,6 +119,8 @@ or a USB 3.0 super-speed micro-B cable. Connection guide for both are shown belo
 
           high-speed micro-B (USB 2.0) connection guide BeagleV Ahead.
 
+.. _beaglev-ahead-flashing-emmc:
+
 Flashing eMMC
 **************
 

boards/beaglev/ahead/05-demos.rst

@@ -3,6 +3,7 @@
 Demos
 #####
 
+
 .. todo::
 
     We need a CSI capture and DSI display demos
@@ -10,3 +11,8 @@ Demos
 .. todo::
 
     We need a cape compatibility layer demo
+
+.. toctree:: 
+    :maxdepth: 1
+    
+    demos-and-tutorials/using-csi

boards/beaglev/ahead/demos-and-tutorials/using-csi.rst

+.. _beaglev-ahead-csi:
+
+.. important:: 
+    This document is a work on progress.
+
+Using CSI Cameras
+#################
+
+.. note:: 
+    CSI support is only available in Yocto image for BeagleV Ahead, 
+    to flash latest Yoctor image on your BeagleV Ahead you can checkout 
+    :ref:`beaglev-ahead-flashing-emmc` section.
+
+
+Hardware
+*********
+
+IMX219 camera modules has been tested to work well with BeagleV Ahead, some of them are listed below:
+
+1. `Raspberry Pi Camera Board v2 - 8 Megapixels (Adafruit) <https://www.adafruit.com/product/3099>`_
+2. `Raspberry Pi NoIR Camera Board v2 - 8 Megapixels (Adafuit) <https://www.adafruit.com/product/3100>`_
+3. `Arducam IMX219 (Robu.in) <https://robu.in/product/arducam-imx219-visible-light-fixed-focus-camera-module-for-raspberry-pi/>`_
+
+In addition to the camer you'll need a 15pin to 22pin cable as well:
+
+1. `Raspberry Pi Zero FPC Camera Cable (Adafruit) <https://www.adafruit.com/product/5211>`_
+2. `Raspberry Pi Zero v1.3 Camera Cable (Adafuit) <https://www.adafruit.com/product/3157>`_
+3. `Raspberry Pi Zero V1.3 Camera Cable (Robu.in) <https://robu.in/product/raspberry-pi-zero-v1-3-camera-cable/>`_
+
+Software
+*********
+
+There are several demo applications available for testing CSI, execute commands 
+below to test your IMX219 camera on CSI0 & CSI1 ports:
+
+1. Change directory to demo application location using: ``cd /usr/share/vi/isp/test``
+2. Set environment variable ``export ISP_LOG_LEVEL=3``
+3. To test CSI0 execute: ``./camera_demo1 2 0 1 0 1920 1080 1 30 7``
+4. To test CSI1 execute: ``./camera_demo1 0 0 1 0 1920 1080 1 30 7``
+
+When you execure `camera_demo1` then you should see something like this on your console:
+
+.. code-block:: bash
+
+    ...
+    ...
+    IMX219: IMX219_IsiExposureControlIss: g=168.960999, Ti=0.050000
+    CAMERIC-MI-IRQ: isp mi frame out (59)  fps[0]: 19.74
+    IMX219: IMX219_IsiExposureControlIss: g=168.960999, Ti=0.050000
+    CAMERIC-MI-IRQ: isp mi frame out (60)  fps[0]: 19.73
+    IMX219: IMX219_IsiExposureControlIss: g=168.960999, Ti=0.050000
+    CAMERIC-MI-IRQ: isp mi frame out (61)  fps[0]: 19.72
+    IMX219: IMX219_IsiExposureControlIss: g=168.960999, Ti=0.050000
+    CAMERIC-MI-IRQ: isp mi frame out (62)  fps[0]: 19.72
+    IMX219: IMX219_IsiExposureControlIss: g=168.960999, Ti=0.050000
+    CAMERIC-MI-IRQ: isp mi frame out (63)  fps[0]: 19.71
+    ...
+    ...
+
+The output above indicates your CSI camera is working well. 
+
+.. important::
+    Usage of other demo applications will be added to this page as well.
+
+Source for these demo application can be found 
+`here <https://github.com/thead-yocto-mirror/csi_hal/tree/master/examples/camera>`_
+