.. _ModifyBSP-57:

Modify The BSP
==============

.. include:: ../substitutions.rst
.. include:: ../../common/developingwithyocto/modifyBSP1.rst

Change the Linux Kernel Device Tree
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Let's try making a small change to the kernel's device tree and enable a heartbeat LED using the User LED1 (\ |heartbeat-ref|\ ) to let us know that the system is alive automatically upon boot (this User LED1 is automatically on by default, checkout the GPIO guide to learn more about controlling it as-is):

.. image:: ../../images/phycore-am57x/AM5_GPIO.png
   :width: 700px
   :alt: phyCORE-AM57x User LEDs

Use your favorite text editor to open the device tree file corresponding to the |product| development kit's carrier board:

**Host (Ubuntu)**

.. parsed-literal::

    vi |kernel-path|\ arch/arm/boot/dts/am57xx-pcm-948.dtsi

Edit the file according to the following diff:

**Device Tree Diff**

.. parsed-literal::

    ...
            led-1 {
                label = "pcm-948:led1";
                gpios = <&gpio1 28 GPIO_ACTIVE_HIGH>;
    -           linux,default-trigger = "mmc1";
    +           linux,default-trigger = "heartbeat";
            };

            led-2 {
    ...

.. include:: ../../common/developingwithyocto/modifyBSP2.rst