Commit 1933861d authored Dec 03, 2013 by Andrzej Pietrasiewicz Committed by Felipe Balbi Dec 12, 2013

usb: gadget: configfs: allow setting function instance's name



USB function's configfs config group is created in a generic way in
usb/gadget/configfs.c:function_make(), which in turn delegates actual
allocation and setup of the USB function instance to a particular
implementation, e.g. in f_acm.c. The said implementation does its job
in a parameter-less function e.g. acm_alloc_instance(), which results
in creating an unnamed config group, whose name is set later in
function_make(). function_make() creates the name by parsing a string
of the form:

<function name>.<instance name>

which comes from userspace as a parameter to mkdir invocation.

Up to now only <function name> has been used, while <instance name>
has been ignored. This patch adds a set_inst_name() operation to
struct usb_function_instance which allows passing the <instance name>
from function_make() so that it is not ignored. It is entirely up to the
implementor of set_inst_name() what to do with the <instance name>.

In a typical case, the struct usb_function_instance is embedded in a
larger struct which is retrieved in set_inst_name() with container_of(),
and the larger struct contains a field to store the <instance name>.

Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

parent b963a81a

drivers/usb/gadget/configfs.c

+7 −0

Original line number	Original line	Diff line number	Diff line
	@@ -564,6 +564,13 @@ static struct config_group *function_make(
	usb_put_function_instance(fi);		usb_put_function_instance(fi);
	return ERR_PTR(ret);		return ERR_PTR(ret);
	}		}
			if (fi->set_inst_name) {
			ret = fi->set_inst_name(fi, instance_name);
			if (ret) {
			usb_put_function_instance(fi);
			return ERR_PTR(ret);
			}
			}

	gi = container_of(group, struct gadget_info, functions_group);		gi = container_of(group, struct gadget_info, functions_group);

include/linux/usb/composite.h

+2 −0

Original line number	Original line	Diff line number	Diff line
	@@ -468,6 +468,8 @@ struct usb_function_instance {
	struct config_group group;		struct config_group group;
	struct list_head cfs_list;		struct list_head cfs_list;
	struct usb_function_driver *fd;		struct usb_function_driver *fd;
			int (set_inst_name)(struct usb_function_instance inst,
			const char *name);
	void (free_func_inst)(struct usb_function_instance inst);		void (free_func_inst)(struct usb_function_instance inst);
	};		};