[PATCH v8 02/16] device property: Add fwnode_graph_get_next_port_endpoint()
From: Chen-Yu Tsai <wenst@chromium.org>
Date: 2026-09-04 08:42:21
Also in:
driver-core, linux-acpi, linux-arm-kernel, linux-mediatek, linux-pm, linux-usb, lkml
Subsystem:
driver core, kobjects, debugfs and sysfs, software nodes and device properties, the rest · Maintainers:
Greg Kroah-Hartman, "Rafael J. Wysocki", Danilo Krummrich, Linus Torvalds
Due to design constraints of the power sequencing API, the consumer
must first be sure that the other side is actually a provider, or it
will continually get -EPROBE_DEFER when requesting the power
sequencing descriptor.
In the upcoming USB power sequencing integration, the USB hub driver
first needs to check whether a graph connection exists, and whether
the other side of the connection is a supported connector type. The
USB port is tied to a "port" firmware node, and this new helper will
be used to get the endpoint under the known "port" firmware node.
Sashiko points out that the |prev| reference put is not done if |port|
is NULL. However it seems that the fwnode_*() and of_*() API design
implicitly makes the functions no-ops if the passed in node is NULL.
So this new addition follows the same pattern.
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Bartosz Golaszewski <redacted>
Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
---
Changes since v2:
- Dropped unused |ep| variable
- Rewrote as do {} while()
- Dropped WARN() use
---
drivers/base/property.c | 25 +++++++++++++++++++++++++
include/linux/property.h | 2 ++
2 files changed, 27 insertions(+)
diff --git a/drivers/base/property.c b/drivers/base/property.c
index 68108805482d..fe7c403e3fa9 100644
--- a/drivers/base/property.c
+++ b/drivers/base/property.c@@ -1109,6 +1109,31 @@ int fwnode_irq_get_byname(const struct fwnode_handle *fwnode, const char *name) } EXPORT_SYMBOL(fwnode_irq_get_byname); +/** + * fwnode_graph_get_next_port_endpoint - Get next endpoint firmware node in port + * @port: Pointer to the target port firmware node + * @prev: Previous endpoint node or %NULL to get the first + * + * The caller is responsible for calling fwnode_handle_put() on the returned + * fwnode pointer. Note that this function also puts a reference to @prev + * unconditionally. + * + * Return: an endpoint firmware node pointer or %NULL if no more endpoints + * are available. + */ +struct fwnode_handle *fwnode_graph_get_next_port_endpoint(const struct fwnode_handle *port, + struct fwnode_handle *prev) +{ + do { + prev = fwnode_get_next_child_node(port, prev); + if (fwnode_name_eq(prev, "endpoint")) + break; + } while (prev); + + return prev; +} +EXPORT_SYMBOL_GPL(fwnode_graph_get_next_port_endpoint); + /** * fwnode_graph_get_next_endpoint - Get next endpoint firmware node * @fwnode: Pointer to the parent firmware node
diff --git a/include/linux/property.h b/include/linux/property.h
index 3dbbd01a52d0..691e792775d5 100644
--- a/include/linux/property.h
+++ b/include/linux/property.h@@ -509,6 +509,8 @@ void __iomem *fwnode_iomap(struct fwnode_handle *fwnode, int index); struct fwnode_handle *fwnode_graph_get_port_by_id(struct fwnode_handle *fwnode, u32 id, unsigned long flags); +struct fwnode_handle *fwnode_graph_get_next_port_endpoint( + const struct fwnode_handle *port, struct fwnode_handle *prev); struct fwnode_handle *fwnode_graph_get_next_endpoint( const struct fwnode_handle *fwnode, struct fwnode_handle *prev); struct fwnode_handle *
--
2.55.0.979.g7e5102b832-goog