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| author | Dmitry Osipenko <digetx@gmail.com> | 2020-07-01 10:42:31 +0300 |
|---|---|---|
| committer | Sam Ravnborg <sam@ravnborg.org> | 2020-07-01 10:49:02 +0200 |
| commit | 4ec0a44ba8d797876ff416fc0317a0169483d240 (patch) | |
| tree | 53a4efb7f4221e32fa8ca7edd1423d4bc107235a /drivers/of | |
| parent | 1185c406f11a49335253036feaa0169c0d174ef8 (diff) | |
| download | linux-4ec0a44ba8d797876ff416fc0317a0169483d240.tar.bz2 | |
of_graph: add of_graph_is_present()
In some cases it's very useful to silently check whether port node exists
at all in a device-tree before proceeding with parsing the graph. The DRM
bridges code is one example of such case where absence of a graph in a
device-tree is a legit condition.
This patch adds of_graph_is_present() which returns true if given
device-tree node contains OF graph port.
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200701074232.13632-2-digetx@gmail.com
Diffstat (limited to 'drivers/of')
| -rw-r--r-- | drivers/of/property.c | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/drivers/of/property.c b/drivers/of/property.c index 1f2086f4e7ce..d3f9fb98e882 100644 --- a/drivers/of/property.c +++ b/drivers/of/property.c @@ -30,6 +30,29 @@ #include "of_private.h" /** + * of_graph_is_present() - check graph's presence + * @node: pointer to device_node containing graph port + * + * Return: True if @node has a port or ports (with a port) sub-node, + * false otherwise. + */ +bool of_graph_is_present(const struct device_node *node) +{ + struct device_node *ports, *port; + + ports = of_get_child_by_name(node, "ports"); + if (ports) + node = ports; + + port = of_get_child_by_name(node, "port"); + of_node_put(ports); + of_node_put(port); + + return !!port; +} +EXPORT_SYMBOL(of_graph_is_present); + +/** * of_property_count_elems_of_size - Count the number of elements in a property * * @np: device node from which the property value is to be read. |