VAR-SOM-AM43 USB OTG host

VAR-SOM-AM43 - USB OTG as host

From a SW perspective, the developer should do the following:

Download a VAR-SOM-AM43 kernel out-of-tree.
Update var-som-am43.dts, as follows:

$ gedit arch/arm/boot/dts/var-som-am43.dts
...
           usb@47401800 {
                               status = "okay";
                               dr_mode = "host"; /* <<-- Add this line */
                        };
...

Build var-som-am43.dtb and replace it on flash / NFS.

Once the var-som-am43.dtb has been replaced on the rootfs - The USB-OTG port will function in Host-only mode.

At this point, the user can simply connect a USB Mouse or DOK to the OTG port.