Manual Pages  — OF_FINDDEVICE

OF_finddevice – find node in device tree

SYNOPSIS DESCRIPTION EXAMPLES SEE ALSO AUTHORS CAVEATS

#include <dev/ofw/ofw_bus.h>

#include <dev/ofw/ofw_bus_subr.h>

phandle_t
OF_finddevice(const char *path);

OF_finddevice() returns the phandle for the node specified by the path. Returns -1 if the path cannot be found in the tree.

    phandle_t root, i2c;

    root = OF_finddevice("/");
    i2c = OF_finddevice("/soc/axi/i2c@a0e0000");
    if (i2c != -1) {
        ...
    }

This manual page was written by Oleksandr Tymoshenko <Mt gonzo@FreeBSD.org>.

The return value should only be checked with equality operators (equal to, not equal to) and not relational comparison (less than, greater than ). There is a discrepancy between IEEE 1275 standard and FreeBSD Ns 's internal representation of a phandle: IEEE 1275 requires the return value of this function to be -1 if the path is not found. But phandle_t is an unsigned type, so it cannot be relationally compared with -1 or 0, this comparison is always true or always false.