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'.

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@amarulasolutions.com --- 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) { + if (of_node_name_eq(child, "port")) + continue; + + if (!of_device_is_available(child)) { + of_node_put(child); + continue; + } + break; + } + + return child; +} +EXPORT_SYMBOL(of_get_non_port_child); + /** * of_get_child_by_name - Find the child node by name for a given parent * @node: parent node diff --git a/include/linux/of.h b/include/linux/of.h index ff143a027abc..3e699becef82 100644 --- a/include/linux/of.h +++ b/include/linux/of.h @@ -290,6 +290,7 @@ extern struct device_node *of_get_next_child(const struct device_node *node, extern struct device_node *of_get_next_available_child( const struct device_node *node, struct device_node *prev);

+extern struct device_node *of_get_non_port_child(const struct device_node *parent); extern struct device_node *of_get_compatible_child(const struct device_node *parent, const char *compatible); extern struct device_node *of_get_child_by_name(const struct device_node *node, @@ -678,6 +679,11 @@ static inline bool of_have_populated_dt(void) return false; }

+static inline struct device_node *of_get_non_port_child(const struct device_node *parent) +{ + return NULL; +} + static inline struct device_node *of_get_compatible_child(const struct device_node *parent, const char *compatible) {

drm_of_find_panel_or_bridge can lookup panel or bridge for a given node based on the OF graph port and endpoint and it fails to use if the given node has a child panel or bridge.

This patch add support to lookup that given node has child panel or bridge however that child node cannot be a 'port'.

Examples OF graph representation of DSI host, which doesn't have 'ports'

dsi { compatible = "allwinner,sun6i-a31-mipi-dsi"; #address-cells = <1>; #size-cells = <0>;

port { dsi_in_tcon0: endpoint { remote-endpoint = <tcon0_out_dsi>; };

panel@0 { reg = <0>; }; };

dsi { compatible = "allwinner,sun6i-a31-mipi-dsi"; #address-cells = <1>; #size-cells = <0>;

port { dsi_in_tcon0: endpoint { remote-endpoint = <tcon0_out_dsi>; };

bridge@0 { reg = <0>;

ports { #address-cells = <1>; #size-cells = <0>;

bridge_out: port@1 { reg = <1>;

bridge_out_panel: endpoint { remote-endpoint = <&panel_out_bridge>; }; }; }; }; };

dsi0 { compatible = "ste,mcde-dsi"; #address-cells = <1>; #size-cells = <0>;

panel@0 { reg = <0>; }; };

Signed-off-by: Jagan Teki jagan@amarulasolutions.com --- drivers/gpu/drm/drm_of.c | 36 ++++++++++++++++++++++++++---------- 1 file changed, 26 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/drm_of.c b/drivers/gpu/drm/drm_of.c index 59d368ea006b..1c4cb809d7bc 100644 --- a/drivers/gpu/drm/drm_of.c +++ b/drivers/gpu/drm/drm_of.c @@ -249,18 +249,34 @@ int drm_of_find_panel_or_bridge(const struct device_node *np, if (panel) *panel = NULL;

- /* - * of_graph_get_remote_node() produces a noisy error message if port - * node isn't found and the absence of the port is a legit case here, - * so at first we silently check whether graph presents in the - * device-tree node. + /** + * Some OF graphs don't require 'ports' to represent the next output + * instead, it simply adds a child node on a given parent node. + * Lookup that child node for a given parent however that child + * cannot be a 'port'. + * + * Add precedence to lookup non port child as of_graph_get_remote_node() + * returns valid even if OF graph has 'port' but that OF graph remote + * node is not register panel or bridge. */ - if (!of_graph_is_present(np)) - return -ENODEV; + if (!of_get_child_by_name(np, "ports")) { + remote = of_get_non_port_child(np); + if (!remote) + return -ENODEV; + } else { + /* + * of_graph_get_remote_node() produces a noisy error message if port + * node isn't found and the absence of the port is a legit case here, + * so at first we silently check whether graph presents in the + * device-tree node. + */ + if (!of_graph_is_present(np)) + return -ENODEV;

- remote = of_graph_get_remote_node(np, port, endpoint); - if (!remote) - return -ENODEV; + remote = of_graph_get_remote_node(np, port, endpoint); + if (!remote) + return -ENODEV; + }

if (panel) { *panel = of_drm_find_panel(remote);