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 <sjg@chromium.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

All the uclass functions for finding a device end up creating a uclass
if it doesn't exist. Add a function which instead returns NULL in this
case.

This is useful when in the 'unbind' path, since we don't want to undo
any unbinding which has already happened.

Signed-off-by: Simon Glass <sjg@chromium.org>

Correct the function documentation.

Fixes: ca031c082700 ("dm: core: introduce uclass_get_device_by_of_path()")
Reported-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

There's quite a few instances of board-specific code doing

  off = fdt_path_offset(gd->fdt_blob, ...);
  ...
  ret = uclass_get_device_by_of_offset(..., off, &dev);

looking for an eeprom or a pmic via some alias. Such code can be
simplified a little if we have a helper for directly getting a device
via device tree path (including being given as an alias).

Implement it in terms of ofnode rather than raw offsets so that this
will work whether live tree is enabled or not.

Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>

When probing a device fails NULL pointer is returned, and following
devices in uclass list cannot be iterated. Skip to next device on error
instead.

With that the only condition under which these simple iteration
functions return error is when the dm is not initialized at uclass_get
time. This is not all that interesting, change return type to void.

Fixes: 6494d708bf ("dm: Add base driver model support")
Signed-off-by: Michal Suchanek <msuchanek@suse.de>
Reviewed-by: Simon Glass <sjg@chromium.org>

Clarify documentation, fix a few more cases that could be broken by the
change.

Signed-off-by: Michal Suchanek <msuchanek@suse.de>

The _err variant iterators use the simple iterators without suffix as
basis.

However, there is no user that uclass_next_device_err for iteration,
many users of uclass_first_device_err use it to get the first and
(assumed) only device of an uclass, and a couple that use
uclass_next_device_err to get the device following a known device in the
uclass list.

While there are some truly singleton device classes in which more than
one device cannot exist these are quite rare, and most classes can have
multiple devices even if it is not the case on the SoC's EVB.

In a later patch the simple iterators will be updated to not stop on
error and return next device instead. With this in many cases the code
that expects the first device or an error if it fails to probe may get
the next device instead. Use the _check iterators as the basis of _err
iterators to preserve the old behavior.

Signed-off-by: Michal Suchanek <msuchanek@suse.de>
Reviewed-by: Simon Glass <sjg@chromium.org>

The return value is not used for anythig, and in a later patch the
behavior of the _err iterator will change in an incompatible way.

Signed-off-by: Michal Suchanek <msuchanek@suse.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
Update pvblock_probe() to avoid using internal var:
Signed-off-by: Simon Glass <sjg@chromium.org>

It seems that namelen is more common in U-Boot. Rename this function to
fit in better. Also fix a bug where it breaks the operation of
uclass_get_by_name() and add a test.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reported-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Reported-by: Tim Harvey <tharvey@gateworks.com>

Improve some of the comments in these files, which don't follow the
correct style.

Signed-off-by: Simon Glass <sjg@chromium.org>