Hi Laurent
On 29/12/2022 00:18, Laurent Pinchart wrote:
Hi Dan,
On Mon, Nov 21, 2022 at 09:25:08AM +0000, Daniel Scally wrote:
Hello all
This series adds support for the definition of extension units in configfs for
the UVC Gadget. The XUs are modelled as config_items within a new "extensions"
group under control, which seemed like an appropriate place to put them.
To allow the XU's to be inserted in the function graph, the bSourceID attribute
for the default output terminal is made writeable - users will need to configure
it with the bUnitID of the XU that they want to use as the OT's source. This does
mean that the XUs can _only_ be placed immediately preceding the OT, but I think
that that's fine for now.
Is this something that we'll be able to extend later in a
backward-compatible way ?
Yes...placing the XUs requires users to set the source of the Output
Terminal and the XU. If we later make them placeable anywhere in the
chain they'd just have to be set differently, I think it's fine.
Please also note that, in general, nothing prevents a device from
exposing multiple XUs, as well as exposing XUs that are not linked in
the IT to OT pipeline. Is this also something we'll be able to support
if needed ?
I've tried both scenarios already and found no problems.
Series level changes:
- Added patches 5-9 which additionally add the ability to create string
descriptors through configfs and link them to the extension units as well as
to override the default descriptors for the IAD and VC/VS interfaces
The XUs configured through this series have been tested via uvc-gadget, uvcvideo
and uvcdynctrl.
Do you have an example script that shows how to create and link an XU
through configfs ? That would give an overview of the feature, useful
for review.
Yes, but it's not currently public. I can get it updated to the
uvc-gadget master branch before I'll get round to a v3 of this series so
I can link it on that submission.
Daniel Scally (9):
usb: gadget: uvc: Make bSourceID read/write
usb: gadget: uvc: Generalise helper functions for reuse
usb: gadget: uvc: Allow definition of XUs in configfs
usb: gadget: uvc: Copy XU descriptors during .bind()
usb: gadget: uvc: Support arbitrary string descriptors
usb: gadget: uvc: Allow linking XUs to string descriptors
usb: gadget: uvc: Attach custom string descriptors
usb: gadget: uvc: Allow linking function to string descs
usb: gadget: uvc: Use custom strings if available
.../ABI/testing/configfs-usb-gadget-uvc | 50 +-
drivers/usb/gadget/function/f_uvc.c | 134 +-
drivers/usb/gadget/function/u_uvc.h | 22 +
drivers/usb/gadget/function/uvc.h | 1 +
drivers/usb/gadget/function/uvc_configfs.c | 1087 ++++++++++++++++-
drivers/usb/gadget/function/uvc_configfs.h | 60 +
6 files changed, 1283 insertions(+), 71 deletions(-)
