On Wed, Dec 8, 2021 at 2:20 AM Rob Herring <robh+dt@xxxxxxxxxx> wrote: > > On Mon, Dec 6, 2021 at 11:49 PM Jagan Teki <jagan@xxxxxxxxxxxxxxxxxxxx> wrote: > > > > Add of_get_non_port_child() helper that can be used to lookup > > non port child nodes. > > > > Some OF graphs don't require 'ports' to represent the next output > > instead, it simply adds a child node on a given parent node. This > > helper lookup that child node, however that child node is not a > > 'port' on given parent as 'port' based nodes are looked up via > > of_graph_get_remote_node(). > > > > Example OF graph representation of DSI host, which doesn't > > have 'ports'. > > This seems pretty specific to DSI and also can't handle there being > more than 1 non-port node. That's allowed for DSI too, but I don't > think I've ever seen a case. Anyways, I'd just move this to DRM rather > than common DT code. One comment on the implementation that will > shrink it. I think it can be possible to OF graph even for non-DSI, however if the end-node outputs to a panel or bridge. At the moment, I can one use case on the non-DSI side is rcar du encoder. https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/drivers/gpu/drm/rcar-du/rcar_du_encoder.c#n68 I'm not sure this can be done existing of_graph_get_remote_node, but an example. > > > > > dsi { > > #address-cells = <1>; > > #size-cells = <0>; > > > > port { > > dsi_in_tcon0: endpoint { > > remote-endpoint = <tcon0_out_dsi>; > > }; > > > > panel@0 { > > reg = <0>; > > }; > > }; > > > > Signed-off-by: Jagan Teki <jagan@xxxxxxxxxxxxxxxxxxxx> > > --- > > drivers/of/base.c | 29 +++++++++++++++++++++++++++++ > > include/linux/of.h | 6 ++++++ > > 2 files changed, 35 insertions(+) > > > > diff --git a/drivers/of/base.c b/drivers/of/base.c > > index 61de453b885c..31bbf885b0f8 100644 > > --- a/drivers/of/base.c > > +++ b/drivers/of/base.c > > @@ -854,6 +854,35 @@ struct device_node *of_get_compatible_child(const struct device_node *parent, > > } > > EXPORT_SYMBOL(of_get_compatible_child); > > > > +/** > > + * of_get_non_port_child - Find the non port child node for a given parent > > + * @node: parent node > > + * > > + * This function looks for child node which is not port child for given parent. > > + * > > + * Return: A node pointer if found, with refcount incremented, use > > + * of_node_put() on it when done. > > + * Returns NULL if node is not found. > > + */ > > +struct device_node *of_get_non_port_child(const struct device_node *parent) > > +{ > > + struct device_node *child; > > + > > + for_each_child_of_node(parent, child) { > > for_each_available_child_of_node Look like this simplifies not required to use of_device_is_available, I will use it in v2. Thanks, Jagan.
