[PATCH] cdev documentation (cf3e43db) · Commits · e / devices / android_kernel_fairphone_FP3

Documentation/DocBook/kernel-api.tmpl

+5 −0

Original line number	Diff line number	Diff line
		@@ -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

fs/char_dev.c

+59 −0

Original line number	Diff line number	Diff line
		@@ -183,6 +183,15 @@ __unregister_chrdev_region(unsigned major, unsigned baseminor, int minorct)
		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;
		@@ -208,6 +217,17 @@ int register_chrdev_region(dev_t from, unsigned count, const char *name)
		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)
		{
		@@ -277,6 +297,15 @@ int register_chrdev(unsigned int major, const char *name,
		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;
		@@ -414,6 +443,16 @@ static int exact_lock(dev_t dev, void *data)
		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;
		@@ -426,6 +465,13 @@ static void cdev_unmap(dev_t dev, unsigned count)
		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);
		@@ -454,6 +500,11 @@ static struct kobj_type ktype_cdev_dynamic = {
		.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);
		@@ -465,6 +516,14 @@ 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);