linux.git/include/linux/fwnode.h, branch v7.1-rc2

device property: Make modifications of fwnode "flags" thread safe

2026-03-26T21:00:59+00:00

In various places in the kernel, we modify the fwnode "flags" member
by doing either:
  fwnode->flags |= SOME_FLAG;
  fwnode->flags &= ~SOME_FLAG;

This type of modification is not thread-safe. If two threads are both
mucking with the flags at the same time then one can clobber the
other.

While flags are often modified while under the "fwnode_link_lock",
this is not universally true.

Create some accessor functions for setting, clearing, and testing the
FWNODE flags and move all users to these accessor functions. New
accessor functions use set_bit() and clear_bit(), which are
thread-safe.

Cc: stable@vger.kernel.org
Fixes: c2c724c868c4 ("driver core: Add fw_devlink_parse_fwtree()")
Reviewed-by: Andy Shevchenko 
Acked-by: Mark Brown 
Reviewed-by: Wolfram Sang 
Signed-off-by: Douglas Anderson 
Reviewed-by: Rafael J. Wysocki (Intel) 
Reviewed-by: Saravana Kannan 
Link: https://patch.msgid.link/20260317090112.v2.1.I0a4d03104ecd5103df3d76f66c8d21b1d15a2e38@changeid
[ Fix fwnode_clear_flag() argument alignment, restore dropped blank
  line in fwnode_dev_initialized(), and remove unnecessary parentheses
  around fwnode_test_flag() calls. - Danilo ]
Signed-off-by: Danilo Krummrich

device property: Add a note to the fwnode.h

2025-04-15T16:10:57+00:00

Add a note to the fwnode.h that the header should not be used
directly in the leaf drivers, they all should use the higher
level APIs and the respective headers.

The purpose of this note is to give guidance to driver writers
to avoid repeating a common mistake.

Signed-off-by: Andy Shevchenko 
Reviewed-by: Sakari Ailus 
Reviewed-by: Rafael J. Wysocki 
Reviewed-by: Zijun Hu 
Link: https://lore.kernel.org/r/20250408095229.1298005-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman

of: property: Increase NR_FWNODE_REFERENCE_ARGS

2025-02-26T19:15:57+00:00

Currently, the following two macros have different values:

// The maximal argument count for firmware node reference
 #define NR_FWNODE_REFERENCE_ARGS	8
// The maximal argument count for DT node reference
 #define MAX_PHANDLE_ARGS 16

It may cause firmware node reference's argument count out of range if
directly assign DT node reference's argument count to firmware's.

drivers/of/property.c:of_fwnode_get_reference_args() is doing the direct
assignment, so may cause firmware's argument count @args->nargs got out
of range, namely, in [9, 16].

Fix by increasing NR_FWNODE_REFERENCE_ARGS to 16 to meet DT requirement.
Will align both macros later to avoid such inconsistency.

Fixes: 3e3119d3088f ("device property: Introduce fwnode_property_get_reference_args")
Signed-off-by: Zijun Hu 
Acked-by: Sakari Ailus 
Link: https://lore.kernel.org/r/20250225-fix_arg_count-v4-1-13cdc519eb31@quicinc.com
Signed-off-by: Rob Herring (Arm)

device property: Split property reading bool and presence test ops

2025-01-13T23:47:29+00:00

The fwnode/device property API currently implement
(fwnode|device)_property_read_bool() with (fwnode|device)_property_present().
That does not allow having different behavior depending on the backend.

Specifically, the usage of (fwnode|device)_property_read_bool() on
non-boolean properties is deprecated on DT. In order to add a warning
on this deprecated use, these 2 APIs need separate ops for the backend.

Acked-by: Greg Kroah-Hartman 
Reviewed-by: Krzysztof Kozlowski 
Acked-by: Rafael J. Wysocki 
Link: https://lore.kernel.org/r/20250109-dt-type-warnings-v1-1-0150e32e716c@kernel.org
Signed-off-by: Rob Herring (Arm)

driver core: Add FWLINK_FLAG_IGNORE to completely ignore a fwnode link

2024-03-07T22:10:01+00:00

A fwnode link between specific supplier-consumer fwnodes can be added
multiple times for multiple reasons. If that dependency doesn't exist,
deleting the fwnode link once doesn't guarantee that it won't get created
again.

So, add FWLINK_FLAG_IGNORE flag to mark a fwnode link as one that needs to
be completely ignored. Since a fwnode link's flags is an OR of all the
flags passed to all the fwnode_link_add() calls to create that specific
fwnode link, the FWLINK_FLAG_IGNORE flag is preserved and can be used to
mark a fwnode link as on that need to be completely ignored until it is
deleted.

Signed-off-by: Saravana Kannan 
Acked-by: "Rafael J. Wysocki" 
Reviewed-by: Rob Herring 
Link: https://lore.kernel.org/r/20240305050458.1400667-3-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman

driver core: Adds flags param to fwnode_link_add()

2024-03-07T22:10:01+00:00

Allow the callers to set fwnode link flags when adding fwnode links.

Signed-off-by: Saravana Kannan 
Acked-by: "Rafael J. Wysocki" 
Reviewed-by: Rob Herring 
Link: https://lore.kernel.org/r/20240305050458.1400667-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman

device property: Don't use "proxy" headers

2024-03-07T22:07:26+00:00

Update header inclusions to follow IWYU (Include What You Use)
principle.

Reviewed-by: Sakari Ailus 
Acked-by: "Rafael J. Wysocki" 
Signed-off-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20240301180138.271590-5-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman

device property: Move enum dev_dma_attr to fwnode.h

2024-03-07T22:07:24+00:00

The struct fwnode_operations defines one of the callback to return
enum dev_dma_attr. But this currently is defined in property.h.
Move it to the correct location.

Reviewed-by: Sakari Ailus 
Acked-by: "Rafael J. Wysocki" 
Signed-off-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20240301180138.271590-4-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman

driver core: Move fw_devlink stuff to where it belongs

2024-03-07T22:07:22+00:00

A few APIs, i.e. fwnode_is_ancestor_of(), fwnode_get_next_parent_dev(),
and get_dev_from_fwnode(), that belong specifically to the fw_devlink APIs,
may be static, but they are not.

Resolve this mess by moving them to the driver/base/core where the all
users are being resided and make static.

No functional changes intended.

Reviewed-by: Sakari Ailus 
Acked-by: "Rafael J. Wysocki" 
Signed-off-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20240301180138.271590-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman

driver core: Drop unneeded 'extern' keyword in fwnode.h

2024-03-07T22:07:20+00:00

We do not use 'extern' keyword with functions. Remove the last one
mistakenly added to fwnode.h.

Reviewed-by: Sakari Ailus 
Acked-by: Saravana Kannan 
Acked-by: "Rafael J. Wysocki" 
Signed-off-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20240301180138.271590-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman