[PATCH] debugfs: Add debugfs_create_ulong()

[Viresh Kumar]

Add debugfs_create_ulong() for the users of type 'unsigned long'. These
will be 32 bits long on a 32 bit machine and 64 bits long on a 64 bit
machine and so can't use the traditional debugfs_create_u64() or
debugfs_create_u32() APIs.

Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
---
Hi Greg,

I thought there were few supporters of this interface and I need it for
the OPP debugfs stuff. So this is an attempt to move the discussion out
of the closed thread, to an open one where others can join.

And if all goes well, then you can apply it directly. Its tested with
the OPP debugfs stuff :)

 fs/debugfs/file.c       | 55 +++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/debugfs.h |  4 ++++
 2 files changed, 59 insertions(+)

diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c
index b70c20fae502..28a7fe6ea618 100644
--- a/fs/debugfs/file.c
+++ b/fs/debugfs/file.c
@@ -251,6 +251,60 @@ struct dentry *debugfs_create_u64(const char *name, umode_t mode,
 }
 EXPORT_SYMBOL_GPL(debugfs_create_u64);
 
+static int debugfs_ulong_set(void *data, u64 val)
+{
+	*(unsigned long *)data = val;
+	return 0;
+}
+
+static int debugfs_ulong_get(void *data, u64 *val)
+{
+	*val = *(unsigned long *)data;
+	return 0;
+}
+DEFINE_SIMPLE_ATTRIBUTE(fops_ulong, debugfs_ulong_get, debugfs_ulong_set, "%llu\n");
+DEFINE_SIMPLE_ATTRIBUTE(fops_ulong_ro, debugfs_ulong_get, NULL, "%llu\n");
+DEFINE_SIMPLE_ATTRIBUTE(fops_ulong_wo, NULL, debugfs_ulong_set, "%llu\n");
+
+/**
+ * debugfs_create_ulong - create a debugfs file that is used to read and write
+ * an unsigned long value.
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is %NULL, then the
+ *          file will be created in the root of the debugfs filesystem.
+ * @value: a pointer to the variable that the file should read to and write
+ *         from.
+ *
+ * This function creates a file in debugfs with the given name that
+ * contains the value of the variable @value.  If the @mode variable is so
+ * set, it can be read from, and written to.
+ *
+ * This function will return a pointer to a dentry if it succeeds.  This
+ * pointer must be passed to the debugfs_remove() function when the file is
+ * to be removed (no automatic cleanup happens if your module is unloaded,
+ * you are responsible here.)  If an error occurs, %NULL will be returned.
+ *
+ * If debugfs is not enabled in the kernel, the value -%ENODEV will be
+ * returned.  It is not wise to check for this value, but rather, check for
+ * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
+ * code.
+ */
+struct dentry *debugfs_create_ulong(const char *name, umode_t mode,
+				    struct dentry *parent, unsigned long *value)
+{
+	/* if there are no write bits set, make read only */
+	if (!(mode & S_IWUGO))
+		return debugfs_create_file(name, mode, parent, value, &fops_ulong_ro);
+	/* if there are no read bits set, make write only */
+	if (!(mode & S_IRUGO))
+		return debugfs_create_file(name, mode, parent, value, &fops_ulong_wo);
+
+	return debugfs_create_file(name, mode, parent, value, &fops_ulong);
+}
+EXPORT_SYMBOL_GPL(debugfs_create_ulong);
+
 DEFINE_SIMPLE_ATTRIBUTE(fops_x8, debugfs_u8_get, debugfs_u8_set, "0x%02llx\n");
 DEFINE_SIMPLE_ATTRIBUTE(fops_x8_ro, debugfs_u8_get, NULL, "0x%02llx\n");
 DEFINE_SIMPLE_ATTRIBUTE(fops_x8_wo, NULL, debugfs_u8_set, "0x%02llx\n");
@@ -264,6 +318,7 @@ DEFINE_SIMPLE_ATTRIBUTE(fops_x32_ro, debugfs_u32_get, NULL, "0x%08llx\n");
 DEFINE_SIMPLE_ATTRIBUTE(fops_x32_wo, NULL, debugfs_u32_set, "0x%08llx\n");
 
 DEFINE_SIMPLE_ATTRIBUTE(fops_x64, debugfs_u64_get, debugfs_u64_set, "0x%016llx\n");
+DEFINE_SIMPLE_ATTRIBUTE(fops_xlong, debugfs_ulong_get, debugfs_ulong_set, "0x%016llx\n");
 
 /*
  * debugfs_create_x{8,16,32,64} - create a debugfs file that is used to read and write an unsigned {8,16,32,64}-bit value
diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h
index 8321fe3058d6..60b150248b54 100644
--- a/include/linux/debugfs.h
+++ b/include/linux/debugfs.h
@@ -79,6 +79,8 @@ 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);
+struct dentry *debugfs_create_ulong(const char *name, umode_t mode,
+				    struct dentry *parent, unsigned long *value);
 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,
@@ -87,6 +89,8 @@ 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);
+struct dentry *debugfs_create_xlong(const char *name, umode_t mode,
+				    struct dentry *parent, unsigned long *value);
 struct dentry *debugfs_create_size_t(const char *name, umode_t mode,
 				     struct dentry *parent, size_t *value);
 struct dentry *debugfs_create_atomic_t(const char *name, umode_t mode,
-- 
2.4.0

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