The patch titled
cdev documentation
has been added to the -mm tree. Its filename is
cdev-documentation-was-drop-second-arg-of-unregister_chrdev.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: cdev documentation
From: corbet@xxxxxxx (Jonathan Corbet)
Add some documentation comments for the cdev interface.
Signed-off-by: Jonathan Corbet <corbet@xxxxxxx>
Cc: Rolf Eike Beer <eike-kernel@xxxxxxxxx>
Cc: "Randy.Dunlap" <rdunlap@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
Documentation/DocBook/kernel-api.tmpl | 5 ++
fs/char_dev.c | 59 ++++++++++++++++++++++++
2 files changed, 64 insertions(+)
diff -puN Documentation/DocBook/kernel-api.tmpl~cdev-documentation-was-drop-second-arg-of-unregister_chrdev Documentation/DocBook/kernel-api.tmpl
--- a/Documentation/DocBook/kernel-api.tmpl~cdev-documentation-was-drop-second-arg-of-unregister_chrdev
+++ a/Documentation/DocBook/kernel-api.tmpl
@@ -454,6 +454,11 @@ X!Edrivers/pnp/system.c
!Eblock/ll_rw_blk.c
</chapter>
+ <chapter id="chrdev">
+ <title>Char devices</title>
+!Efs/char_dev.c
+ </chapter>
+
<chapter id="miscdev">
<title>Miscellaneous Devices</title>
!Edrivers/char/misc.c
diff -puN fs/char_dev.c~cdev-documentation-was-drop-second-arg-of-unregister_chrdev fs/char_dev.c
--- a/fs/char_dev.c~cdev-documentation-was-drop-second-arg-of-unregister_chrdev
+++ a/fs/char_dev.c
@@ -164,6 +164,15 @@ __unregister_chrdev_region(unsigned majo
return cd;
}
+/**
+ * register_chrdev_region() - register a range of device numbers
+ * @from: the first in the desired range of device numbers; must include
+ * the major number.
+ * @count: the number of consecutive device numbers required
+ * @name: the name of the device or driver.
+ *
+ * Return value is zero on success, a negative error code on failure.
+ */
int register_chrdev_region(dev_t from, unsigned count, const char *name)
{
struct char_device_struct *cd;
@@ -189,6 +198,17 @@ fail:
return PTR_ERR(cd);
}
+/**
+ * alloc_chrdev_region() - register a range of char device numbers
+ * @dev: output parameter for first assigned number
+ * @baseminor: first of the requested range of minor numbers
+ * @count: the number of minor numbers required
+ * @name: the name of the associated device or driver
+ *
+ * Allocates a range of char device numbers. The major number will be
+ * chosen dynamically, and returned (along with the first minor number)
+ * in @dev. Returns zero or a negative error code.
+ */
int alloc_chrdev_region(dev_t *dev, unsigned baseminor, unsigned count,
const char *name)
{
@@ -258,6 +278,15 @@ out2:
return err;
}
+/**
+ * unregister_chrdev_region() - return a range of device numbers
+ * @from: the first in the range of numbers to unregister
+ * @count: the number of device numbers to unregister
+ *
+ * This function will unregister a range of @count device numbers,
+ * starting with @from. The caller should normally be the one who
+ * allocated those numbers in the first place...
+ */
void unregister_chrdev_region(dev_t from, unsigned count)
{
dev_t to = from + count;
@@ -395,6 +424,16 @@ static int exact_lock(dev_t dev, void *d
return cdev_get(p) ? 0 : -1;
}
+/**
+ * cdev_add() - add a char device to the system
+ * @p: the cdev structure for the device
+ * @dev: the first device number for which this device is responsible
+ * @count: the number of consecutive minor numbers corresponding to this
+ * device
+ *
+ * cdev_add() adds the device represented by @p to the system, making it
+ * live immediately. A negative error code is returned on failure.
+ */
int cdev_add(struct cdev *p, dev_t dev, unsigned count)
{
p->dev = dev;
@@ -407,6 +446,13 @@ static void cdev_unmap(dev_t dev, unsign
kobj_unmap(cdev_map, dev, count);
}
+/**
+ * cdev_del() - remove a cdev from the system
+ * @p: the cdev structure to be removed
+ *
+ * cdev_del() removes @p from the system, possibly freeing the structure
+ * itself.
+ */
void cdev_del(struct cdev *p)
{
cdev_unmap(p->dev, p->count);
@@ -435,6 +481,11 @@ static struct kobj_type ktype_cdev_dynam
.release = cdev_dynamic_release,
};
+/**
+ * cdev_alloc() - allocate a cdev structure
+ *
+ * Allocates and returns a cdev structure, or NULL on failure.
+ */
struct cdev *cdev_alloc(void)
{
struct cdev *p = kzalloc(sizeof(struct cdev), GFP_KERNEL);
@@ -446,6 +497,14 @@ struct cdev *cdev_alloc(void)
return p;
}
+/**
+ * cdev_init() - initialize a cdev structure
+ * @cdev: the structure to initialize
+ * @fops: the file_operations for this device
+ *
+ * Initializes @cdev, remembering @fops, making it ready to add to the
+ * system with cdev_add().
+ */
void cdev_init(struct cdev *cdev, const struct file_operations *fops)
{
memset(cdev, 0, sizeof *cdev);
_
Patches currently in -mm which might be from corbet@xxxxxxx are
cdev-documentation-was-drop-second-arg-of-unregister_chrdev.patch
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