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authorLinus Torvalds <torvalds@linux-foundation.org>2019-11-27 11:06:20 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2019-11-27 11:06:20 -0800
commit9a3d7fd275be4559277667228902824165153c80 (patch)
tree09e74ef51c6388ac42b6123ad789ebc5b6ad8ed6 /Documentation/filesystems
parent0dd09bc02c1bad55e92306ca83b38b3cf48b9f40 (diff)
parent0e4a459f56c32d3e52ae69a4b447db2f48a65f44 (diff)
Merge tag 'driver-core-5.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core updates from Greg KH: "Here is the "big" set of driver core patches for 5.5-rc1 There's a few minor cleanups and fixes in here, but the majority of the patches in here fall into two buckets: - debugfs api cleanups and fixes - driver core device link support for boot dependancy issues The debugfs api cleanups are working to slowly refactor the debugfs apis so that it is even harder to use incorrectly. That work has been happening for the past few kernel releases and will continue over time, it's a long-term project/goal The driver core device link support missed 5.4 by just a bit, so it's been sitting and baking for many months now. It's from Saravana Kannan to help resolve the problems that DT-based systems have at boot time with dependancy graphs and kernel modules. Turns out that no one has actually tried to build a generic arm64 kernel with loads of modules and have it "just work" for a variety of platforms (like a distro kernel). The big problem turned out to be a lack of dependency information between different areas of DT entries, and the work here resolves that problem and now allows devices to boot properly, and quicker than a monolith kernel. All of these patches have been in linux-next for a long time with no reported issues" * tag 'driver-core-5.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (68 commits) tracing: Remove unnecessary DEBUG_FS dependency of: property: Add device link support for interrupt-parent, dmas and -gpio(s) debugfs: Fix !DEBUG_FS debugfs_create_automount of: property: Add device link support for "iommu-map" of: property: Fix the semantics of of_is_ancestor_of() i2c: of: Populate fwnode in of_i2c_get_board_info() drivers: base: Fix Kconfig indentation firmware_loader: Fix labels with comma for builtin firmware driver core: Allow device link operations inside sync_state() driver core: platform: Declare ret variable only once cpu-topology: declare parse_acpi_topology in <linux/arch_topology.h> crypto: hisilicon: no need to check return value of debugfs_create functions driver core: platform: use the correct callback type for bus_find_device firmware_class: make firmware caching configurable driver core: Clarify documentation for fwnode_operations.add_links() mailbox: tegra: Fix superfluous IRQ error message net: caif: Fix debugfs on 64-bit platforms mac80211: Use debugfs_create_xul() helper media: c8sectpfe: no need to check return value of debugfs_create functions of: property: Add device link support for iommus, mboxes and io-channels ...
Diffstat (limited to 'Documentation/filesystems')
-rw-r--r--Documentation/filesystems/debugfs.txt50
1 files changed, 29 insertions, 21 deletions
diff --git a/Documentation/filesystems/debugfs.txt b/Documentation/filesystems/debugfs.txt
index 9e27c843d00e..dc497b96fa4f 100644
--- a/Documentation/filesystems/debugfs.txt
+++ b/Documentation/filesystems/debugfs.txt
@@ -68,41 +68,49 @@ actually necessary; the debugfs code provides a number of helper functions
for simple situations. Files containing a single integer value can be
created with any of:
- struct dentry *debugfs_create_u8(const char *name, umode_t mode,
- struct dentry *parent, u8 *value);
- struct dentry *debugfs_create_u16(const char *name, umode_t mode,
- struct dentry *parent, u16 *value);
+ void debugfs_create_u8(const char *name, umode_t mode,
+ struct dentry *parent, u8 *value);
+ void debugfs_create_u16(const char *name, umode_t mode,
+ struct dentry *parent, u16 *value);
struct dentry *debugfs_create_u32(const char *name, umode_t mode,
struct dentry *parent, u32 *value);
- struct dentry *debugfs_create_u64(const char *name, umode_t mode,
- struct dentry *parent, u64 *value);
+ void debugfs_create_u64(const char *name, umode_t mode,
+ struct dentry *parent, u64 *value);
These files support both reading and writing the given value; if a specific
file should not be written to, simply set the mode bits accordingly. The
values in these files are in decimal; if hexadecimal is more appropriate,
the following functions can be used instead:
- struct dentry *debugfs_create_x8(const char *name, umode_t mode,
- struct dentry *parent, u8 *value);
- struct dentry *debugfs_create_x16(const char *name, umode_t mode,
- struct dentry *parent, u16 *value);
- struct dentry *debugfs_create_x32(const char *name, umode_t mode,
- struct dentry *parent, u32 *value);
- struct dentry *debugfs_create_x64(const char *name, umode_t mode,
- struct dentry *parent, u64 *value);
+ void debugfs_create_x8(const char *name, umode_t mode,
+ struct dentry *parent, u8 *value);
+ void debugfs_create_x16(const char *name, umode_t mode,
+ struct dentry *parent, u16 *value);
+ void debugfs_create_x32(const char *name, umode_t mode,
+ struct dentry *parent, u32 *value);
+ void debugfs_create_x64(const char *name, umode_t mode,
+ struct dentry *parent, u64 *value);
These functions are useful as long as the developer knows the size of the
value to be exported. Some types can have different widths on different
-architectures, though, complicating the situation somewhat. There is a
-function meant to help out in one special case:
+architectures, though, complicating the situation somewhat. There are
+functions meant to help out in such special cases:
- struct dentry *debugfs_create_size_t(const char *name, umode_t mode,
- struct dentry *parent,
- size_t *value);
+ void debugfs_create_size_t(const char *name, umode_t mode,
+ struct dentry *parent, size_t *value);
As might be expected, this function will create a debugfs file to represent
a variable of type size_t.
+Similarly, there are helpers for variables of type unsigned long, in decimal
+and hexadecimal:
+
+ struct dentry *debugfs_create_ulong(const char *name, umode_t mode,
+ struct dentry *parent,
+ unsigned long *value);
+ void debugfs_create_xul(const char *name, umode_t mode,
+ struct dentry *parent, unsigned long *value);
+
Boolean values can be placed in debugfs with:
struct dentry *debugfs_create_bool(const char *name, umode_t mode,
@@ -114,8 +122,8 @@ lower-case values, or 1 or 0. Any other input will be silently ignored.
Also, atomic_t values can be placed in debugfs with:
- struct dentry *debugfs_create_atomic_t(const char *name, umode_t mode,
- struct dentry *parent, atomic_t *value)
+ void debugfs_create_atomic_t(const char *name, umode_t mode,
+ struct dentry *parent, atomic_t *value)
A read of this file will get atomic_t values, and a write of this file
will set atomic_t values.