Configuring Pins Mode Beaglebone

Question

In the beagleboard or beaglebone are different modes to work the pin. With the previous kernel they are located in /sys/kernel/debug/omap_mux. Do u know with the last Kernel

Answer 1

As it was asked above I will explain the fragment@n magic...the "fragment@n", "target" and "overlay" nodes are specific to the device tree overlay loader which patches an existing Device Tree. These nodes do not end up in the final merged DT, they are just there to tell the overlay loader what to do.

Overlay files can have multiple "patches" to the tree so to speak. Each fragment@n just declares a new patch, the "target" specifies where in the device tree the patch will be copied into and the "overlay" is the contents of the patch. Contents are merged and existing nodes are replaced. Targets can use actual DT path syntax (nodes separated by /) or aliases which is used here (&ocp and &am33xx_pinmux). Aliases are set for important nodes in the DT already.

The "compatible", "part-number" and "version" at the top are also specific to overlays and typically used like filters to determine if an overlay is supported on current hardware. All overlay files have specific syntax up to the overlay node at which point the inner contents is plain old device tree syntax. Kernels may support Device Tree but not overlays in which case you might have to copy and paste fragments into a single DTS/DTB yourself.DT and DTO is a beautiful system for embedded systems and drivers but takes getting used to.