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usb: gadget: uvc: configfs: Add bFrameIndex attributes

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- Add bFrameIndex as a UVCG_FRAME_ATTR_RO for each frame size.
- Automatically assign ascending bFrameIndex to each frame in a format.

Before all "bFrameindex" attributes were set to "1" with no way to
configure the gadget otherwise. This resulted in the host always
negotiating for bFrameIndex 1 (i.e. the first frame size of the gadget).
After the negotiation the host driver will set the user or application
selected frame size, while the gadget is actually set to the first frame
size.

Now, when the containing format is linked into the streaming header,
iterate over all child frame descriptors and assign ascending indices.
The automatically assigned indices can be read from the new read only
bFrameIndex configfs attribute in each frame descriptor item.

Signed-off-by: Joel Pepper <joel.pepper@rwth-aachen.de>
[Simplified documentation, renamed function, blank space update]
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
This commit is contained in:
Joel Pepper 2018-05-29 21:02:13 +02:00 committed by Laurent Pinchart
parent 61ff10e0ea
commit b206548be6
2 changed files with 64 additions and 0 deletions
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8
Documentation/ABI/testing/configfs-usb-gadget-uvc
View file

@ -189,6 +189,10 @@ Date: Dec 2014
KernelVersion: 4.0
Description: Specific MJPEG frame descriptors
bFrameIndex - unique id for this framedescriptor;
only defined after parent format is
linked into the streaming header;
read-only
dwFrameInterval - indicates how frame interval can be
programmed; a number of values
separated by newline can be specified
@ -240,6 +244,10 @@ Date: Dec 2014
KernelVersion: 4.0
Description: Specific uncompressed frame descriptors
bFrameIndex - unique id for this framedescriptor;
only defined after parent format is
linked into the streaming header;
read-only
dwFrameInterval - indicates how frame interval can be
programmed; a number of values
separated by newline can be specified

56
drivers/usb/gadget/function/uvc_configfs.c
View file

@ -868,6 +868,8 @@ static struct uvcg_streaming_header *to_uvcg_streaming_header(struct config_item
return container_of(item, struct uvcg_streaming_header, item);
}
static void uvcg_format_set_indices(struct config_group *fmt);
static int uvcg_streaming_header_allow_link(struct config_item *src,
struct config_item *target)
{
@ -915,6 +917,8 @@ static int uvcg_streaming_header_allow_link(struct config_item *src,
if (!target_fmt)
goto out;
uvcg_format_set_indices(to_config_group(target));
format_ptr = kzalloc(sizeof(*format_ptr), GFP_KERNEL);
if (!format_ptr) {
ret = -ENOMEM;
@ -1146,6 +1150,41 @@ end: \
\
UVC_ATTR(uvcg_frame_, cname, aname);
static ssize_t uvcg_frame_b_frame_index_show(struct config_item *item,
char *page)
{
struct uvcg_frame *f = to_uvcg_frame(item);
struct uvcg_format *fmt;
struct f_uvc_opts *opts;
struct config_item *opts_item;
struct config_item *fmt_item;
struct mutex *su_mutex = &f->item.ci_group->cg_subsys->su_mutex;
int result;
mutex_lock(su_mutex); /* for navigating configfs hierarchy */
fmt_item = f->item.ci_parent;
fmt = to_uvcg_format(fmt_item);
if (!fmt->linked) {
result = -EBUSY;
goto out;
}
opts_item = fmt_item->ci_parent->ci_parent->ci_parent;
opts = to_f_uvc_opts(opts_item);
mutex_lock(&opts->lock);
result = sprintf(page, "%d\n", f->frame.b_frame_index);
mutex_unlock(&opts->lock);
out:
mutex_unlock(su_mutex);
return result;
}
UVC_ATTR_RO(uvcg_frame_, b_frame_index, bFrameIndex);
#define noop_conversion(x) (x)
UVCG_FRAME_ATTR(bm_capabilities, bmCapabilities, noop_conversion,
@ -1294,6 +1333,7 @@ static ssize_t uvcg_frame_dw_frame_interval_store(struct config_item *item,
UVC_ATTR(uvcg_frame_, dw_frame_interval, dwFrameInterval);
static struct configfs_attribute *uvcg_frame_attrs[] = {
&uvcg_frame_attr_b_frame_index,
&uvcg_frame_attr_bm_capabilities,
&uvcg_frame_attr_w_width,
&uvcg_frame_attr_w_height,
@ -1373,6 +1413,22 @@ static void uvcg_frame_drop(struct config_group *group, struct config_item *item
config_item_put(item);
}
static void uvcg_format_set_indices(struct config_group *fmt)
{
struct config_item *ci;
unsigned int i = 1;
list_for_each_entry(ci, &fmt->cg_children, ci_entry) {
struct uvcg_frame *frm;
if (ci->ci_type != &uvcg_frame_type)
continue;
frm = to_uvcg_frame(ci);
frm->frame.b_frame_index = i++;
}
}
/* -----------------------------------------------------------------------------
* streaming/uncompressed/<NAME>
*/