Embed the video_device struct to simplify the error handling and in
order to (eventually) get rid of video_device_alloc/release.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

Switch this driver over to the V4L2 core locking mechanism in preparation
for switching to unlocked_ioctl. Suggested by Laurent Pinchart.

This patch introduces a new mutex at the struct uvc_video level and
drops the old mutex at the queue level. The new lock is now used for all
ioctl locking and in the release file operation (the driver always has
to take care of locking in file operations, the core only serializes
ioctls).

Note that the mmap and get_unmapped_area file operations no longer take
a lock. Commit f035eb4e976ef5a059e30bc91cfd310ff030a7d3 fixed a AB-BA
deadlock by moving all the locking down into vb2, so the mmap and
get_unmapped_area file operations should no longer do any locking before
calling into vb2.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

Add support for using the uvc function as a component of USB gadgets composed
with configfs.

Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

If the caller of uvc_alloc() does not provide enough
descriptors, binding the function should fail, so appropriate
code is returned from uvc_copy_descriptors().

uvc_function_bind() is modified accordingly to account for possible
errors from uvc_copy_descriptors().

Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

When configfs is integrated, CONFIGFS_ATTR_STRUCT and CONFIGFS_ATTR_OPS
macros should be used, but the latter expects that tere is a to_f_uvc_opts
function accepting a config_item, whereas the macro being changed
can be applied to a different type of argument.

Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

when our ->disable() method is called, we must
make sure to teardown all our resources, including
endpoints.

Signed-off-by: Felipe Balbi <balbi@ti.com>

just like any other endpoint, we must enable/disable
our video control endpoint based on calls to our
->set_alt() method.

Signed-off-by: Felipe Balbi <balbi@ti.com>

If our alternate setting has been selected, we must
return that on a subsequent Get Interface request
even if we're not streaming.

Signed-off-by: Felipe Balbi <balbi@ti.com>

If a set_alt() to the same alternate setting that's
already selected is received, functions are required
to reset the interface state, this means we must disable
all endpoints and reenable them again.

This is also documented on our kdoc for struct usb_function

* @set_alt: (REQUIRED) Reconfigures altsettings; function drivers may
*	initialize usb_ep.driver data at this time (when it is used).
*	Note that setting an interface to its current altsetting resets
*	interface state, and that all interfaces have a disabled state.

Signed-off-by: Felipe Balbi <balbi@ti.com>

The struct usb_endpoint_descriptor wMaxPacketSize field the struct
usb_ss_ep_comp_descriptor wBytesPerInterval field are stored in
little-endian format. Convert the values from CPU order to little endian
before storing the values.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>