freebsd-dev/share/man/man9/ofw_graph.9
Emmanuel Vadot 9a4eed0be2 ofw_graph: Add functions for graph bindings
Those functions are helpers to work on graph bindings.
graphs are mostly use with video related devices.
See https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/graph.txt?id=4436a3711e3249840e0679e92d3c951bcaf25515

MFC after:	1 month
Differential Revision:	https://reviews.freebsd.org/D19877
2019-04-17 20:09:01 +00:00

107 lines
3.4 KiB
Groff

.\" Copyright (c) 2019 Emmanuel Vadot <manu@freebsd.org>
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR
.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT,
.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
.\"
.\" $FreeBSD$
.\"
.Dd April 10, 2019
.Dt ofw_graph 9
.Os
.Sh NAME
.Nm ofw_graph ,
.Nm ofw_graph_get_port_by_idx ,
.Nm ofw_graph_port_get_num_endpoints ,
.Nm ofw_graph_get_endpoint_by_idx ,
.Nm ofw_graph_get_remote_endpoint ,
.Nm ofw_graph_get_remote_parent ,
.Nm ofw_graph_get_device_by_port_ep ,
.Nd Helpers for the graph bindings
.Sh SYNOPSIS
.In dev/ofw/openfirm.h
.In dev/ofw/ofw_graph.h
.Ft phandle_t
.Fn ofw_graph_get_port_by_idx "phandle_t node" "uint32_t idx"
.Ft size_t
.Fn ofw_graph_port_get_num_endpoints "phandle_t port"
.Ft phandle_t
.Fn ofw_graph_get_endpoint_by_idx "phandle_t port" "uint32_t idx"
.Ft phandle_t
.Fn ofw_graph_get_remote_endpoint "phandle_t endpoint"
.Ft phandle_t
.Fn ofw_graph_get_remote_parent "phandle_t remote"
.Ft device_t
.Fn ofw_graph_get_device_by_port_ep "phandle_t node" "uint32_t port_id" "uin32_t ep_id"
.Sh DESCRIPTION
.Pp
The ofw_graph functions are helpers to parse the DTS graph bindings
.Pp
.Fn ofw_graph_get_port_by_idx
return the port with id
.Fa idx .
It will first check node named
.Fa port@idx
and then fallback on checking the
.Fa ports
child for a child node matching the id. If no ports matching
.Fa idx
is found the function return 0.
.Pp
.Fn ofw_graph_port_get_num_endpoints
returns the number of endpoints a port node have.
.Pp
.Fn ofw_graph_get_endpoint_by_idx
return the endpoint with id
.Fa idx .
It will first check if there is a single child named
.Fa endpoint
and returns it if there is. If there is multiple endpoints it will check
the
.Fa reg
property and returns the correct
.Fa phandle_t
or 0 if none match.
.Pp
.Fn ofw_graph_get_remote_endpoint
returns the
.Fa remote-endpoint
property if it exists or 0.
.Pp
.Fn ofw_graph_get_remote_parent
returns the device node corresponding to the
.Fa remote-endpoint
phandle or 0 if none.
.Fn ofw_graph_get_device_by_port_ep
returns the device associated with the port and endpoint or
.Fa NULL
if none. The device driver should have called
.Fn OF_device_register_xref
before.
.Fn
.Sh HISTORY
The
.Nm ofw_graph
functions first appeared in
.Fx 13.0 .
The
.Nm ofw_graph
functions and manual page were written by
.An Emmanuel Vadot Aq Mt manu@FreeBSD.org .