ср, 26 бер. 2025 р. о 17:01 Miquel Raynal <miquel.ray...@bootlin.com> пише:
>
> There are already several helpers to find a udevice based on its
> position in a device tree, like getting a child or a node pointed by a
> phandle, but there was no support for graph endpoints, which are very
> common in display pipelines.
>
> Add a new helper, named uclass_get_device_by_endpoint() which enters the
> child graph reprensentation, looks for a specific port, then follows the
> remote endpoint, and finally retrieves the first parent of the given
> uclass_id.
>
> This is a very handy and straightforward way to get a bridge or a panel
> handle.
>
> Reviewed-by: Simon Glass <s...@chromium.org>
> Signed-off-by: Miquel Raynal <miquel.ray...@bootlin.com>
> ---
> drivers/core/uclass.c | 19 +++++++++++++++++++
> include/dm/uclass.h | 24 ++++++++++++++++++++++++
> 2 files changed, 43 insertions(+)
>
> diff --git a/drivers/core/uclass.c b/drivers/core/uclass.c
> index
> f846a35d6b2537bab56bca158cedfb134b37f477..ce5e61bbaa63a181a1ea6781ad6a7f06be67c7e0
> 100644
> --- a/drivers/core/uclass.c
> +++ b/drivers/core/uclass.c
> @@ -16,6 +16,7 @@
> #include <dm/device.h>
> #include <dm/device-internal.h>
> #include <dm/lists.h>
> +#include <dm/ofnode_graph.h>
> #include <dm/uclass.h>
> #include <dm/uclass-internal.h>
> #include <dm/util.h>
> @@ -582,6 +583,24 @@ int uclass_get_device_by_phandle(enum uclass_id id,
> struct udevice *parent,
> ret = uclass_find_device_by_phandle(id, parent, name, &dev);
> return uclass_get_device_tail(dev, ret, devp);
> }
> +
> +int uclass_get_device_by_endpoint(enum uclass_id class_id, struct udevice
> *dev,
> + int port_idx, int ep_idx, struct udevice
> **devp)
> +{
> + ofnode node_source = dev_ofnode(dev);
> + ofnode node_dest = ofnode_graph_get_remote_node(node_source,
> port_idx, ep_idx);
You may use dev_ofnode(dev) directly instead of node_source if you
wish, but that is up to you.
> + struct udevice *target = NULL;
> + int ret;
> +
> + if (!ofnode_valid(node_dest))
> + return -EINVAL;
> +
> + ret = uclass_find_device_by_ofnode(class_id, node_dest, &target);
You can use uclass_get_device_by_ofnode here and avoid using
uclass_get_device_tail later.
> + if (ret)
> + return -ENODEV;
> +
> + return uclass_get_device_tail(target, 0, devp);
> +}
> #endif
>
> /*
> diff --git a/include/dm/uclass.h b/include/dm/uclass.h
> index
> c279304092352200d5297ad2d17f527173ec506b..8fdd72725119aae6ad2b62f4b0c38866a910389c
> 100644
> --- a/include/dm/uclass.h
> +++ b/include/dm/uclass.h
> @@ -333,6 +333,30 @@ int uclass_get_device_by_phandle(enum uclass_id id,
> struct udevice *parent,
> int uclass_get_device_by_driver(enum uclass_id id, const struct driver *drv,
> struct udevice **devp);
>
> +/**
> + * uclass_get_device_by_endpoint() - Get a uclass device for a remote
> endpoint
> + *
> + * This searches through the parents of the specified remote endpoint
> + * for the first device matching the uclass. Said otherwise, this helper
> + * goes through the graph (endpoint) representation and searches for
> + * matching devices. Endpoints can be subnodes of the "port" node or
> + * subnodes of ports identified with a reg property, themselves in a
> + * "ports" container.
> + *
> + * The device is probed to activate it ready for use.
> + *
> + * @class_id: uclass ID to look up
> + * @dev: Device to start from
> + * @port_idx: Index of the port to follow, -1 if there is a single 'port'
> + * node without reg.
> + * @ep_idx: Index of the endpoint to follow, -1 if there is a single
> 'endpoint'
> + * node without reg.
> + * @target: Returns pointer to the first device matching the expected uclass.
> + * Return: 0 if OK, -ve on error
> + */
> +int uclass_get_device_by_endpoint(enum uclass_id class_id, struct udevice
> *dev,
> + int port_idx, int ep_idx, struct udevice
> **target);
> +
> /**
> * uclass_first_device() - Get the first device in a uclass
> *
>
> --
> 2.48.1
>
