3d265fce43
- skipping paragraph macro: Pp after Sh - sections out of conventional order: Sh EXAMPLES - whitespace at end of input line - normalizing date format
74 lines
2.5 KiB
Groff
74 lines
2.5 KiB
Groff
.\"
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.\" Copyright (c) 2018 Oleksandr Tymoshenko <gonzo@FreeBSD.org>
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.\"
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR
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.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT,
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.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd April 9, 2018
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.Dt OF_FINDDEVICE 9
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.Os
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.Sh NAME
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.Nm OF_finddevice
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.Nd find node in device tree
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.Sh SYNOPSIS
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.In dev/ofw/ofw_bus.h
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.In dev/ofw/ofw_bus_subr.h
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.Ft phandle_t
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.Fn OF_finddevice "const char *path"
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.Sh DESCRIPTION
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.Fn OF_finddevice
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returns the phandle for the node specified by the
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.Fa path .
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Returns -1 if the path cannot be found in the tree.
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.Sh EXAMPLES
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.Bd -literal
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phandle_t root, i2c;
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root = OF_finddevice("/");
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i2c = OF_finddevice("/soc/axi/i2c@a0e0000");
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if (i2c != -1) {
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...
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}
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.Ed
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.Sh SEE ALSO
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.Xr OF_child 9
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.Xr OF_parent 9
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.Xr OF_peer 9
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.Sh AUTHORS
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.An -nosplit
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This manual page was written by
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.An Oleksandr Tymoshenko Aq Mt gonzo@FreeBSD.org .
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.Sh CAVEATS
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The return value should only be checked with equality
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operators (equal to, not equal to) and not relational comparison
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(less than, greater than ).
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There is a discrepancy between IEEE 1275 standard and
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.Fx Ns 's
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internal representation of a phandle: IEEE 1275
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requires the return value of this function to be -1 if the path
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is not found.
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But phandle_t is an unsigned type, so it cannot
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be relationally compared with -1 or 0, this comparison
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is always true or always false.
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