xref: /freebsd/share/man/man9/OF_finddevice.9 (revision 77c1fcec914bae1232762ca0b0462abd6957ff26)
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26.\" $FreeBSD$
27.\"
28.Dd April 9, 2018
29.Dt OF_FINDDEVICE 9
30.Os
31.Sh NAME
32.Nm OF_finddevice
33.Nd find node in device tree
34.Sh SYNOPSIS
35.In dev/ofw/ofw_bus.h
36.In dev/ofw/ofw_bus_subr.h
37.Ft phandle_t
38.Fn OF_finddevice "const char *path"
39.Sh DESCRIPTION
40.Pp
41.Fn OF_finddevice
42returns the phandle for the node specified by the
43.Fa path .
44Returns -1 if the path cannot be found in the tree.
45.Sh CAVEATS
46The return value should only be checked with equality
47operators (equal to, not equal to) and not relational comparison
48(less than, greater than ).
49There is a discrepancy between IEEE 1275 standard and
50.Fx Ns 's
51internal representation of a phandle: IEEE 1275
52requires the return value of this function to be -1 if the path
53is not found.
54But phandle_t is an unsigned type, so it cannot
55be relationally compared with -1 or 0, this comparison
56is always true or always false.
57.Sh EXAMPLES
58.Bd -literal
59    phandle_t root, i2c;
60
61    root = OF_finddevice("/");
62    i2c = OF_finddevice("/soc/axi/i2c@a0e0000");
63    if (i2c != -1) {
64        ...
65    }
66.Ed
67.Sh SEE ALSO
68.Xr OF_child 9
69.Xr OF_parent 9
70.Xr OF_peer 9
71.Sh AUTHORS
72.An -nosplit
73This manual page was written by
74.An Oleksandr Tymoshenko Aq Mt gonzo@FreeBSD.org .
75