Allow users to create new color matching descriptors in addition to
the default one. These must be associated with a UVC format in order
to be transmitted to the host, which is achieved by symlinking from
the format to the newly created color matching descriptor - extend
the uncompressed and mjpeg formats to support that linking operation.
Signed-off-by: Daniel Scally <dan.scally@xxxxxxxxxxxxxxxx>
---
Changes in v2:
- New section of the ABI documentation
- uvcg_format_allow_link() now checks to see if an existing link is
already there
- .allow_link() and .drop_link() track color_matching->refcnt
.../ABI/testing/configfs-usb-gadget-uvc | 17 ++++
drivers/usb/gadget/function/uvc_configfs.c | 99 ++++++++++++++++++-
2 files changed, 114 insertions(+), 2 deletions(-)
diff --git a/Documentation/ABI/testing/configfs-usb-gadget-uvc b/Documentation/ABI/testing/configfs-usb-gadget-uvc
index 53258b7c6f2d..e7753b2cb11b 100644
--- a/Documentation/ABI/testing/configfs-usb-gadget-uvc
+++ b/Documentation/ABI/testing/configfs-usb-gadget-uvc
@@ -177,6 +177,23 @@ Description: Default color matching descriptors
white
======================== ======================================
+What: /config/usb-gadget/gadget/functions/uvc.name/streaming/color_matching/name
+Date: Dec 2022
+KernelVersion: 6.3
+Description: Additional color matching descriptors
+
+ All attributes read/write:
+
+ ======================== ======================================
+ bMatrixCoefficients matrix used to compute luma and
+ chroma values from the color primaries
+ bTransferCharacteristics optoelectronic transfer
+ characteristic of the source picture,
+ also called the gamma function
+ bColorPrimaries color primaries and the reference
+ white
+ ======================== ======================================
+
What: /config/usb-gadget/gadget/functions/uvc.name/streaming/mjpeg
Date: Dec 2014
KernelVersion: 4.0
diff --git a/drivers/usb/gadget/function/uvc_configfs.c b/drivers/usb/gadget/function/uvc_configfs.c
index ef5d75942f24..3be6ca936851 100644
--- a/drivers/usb/gadget/function/uvc_configfs.c
+++ b/drivers/usb/gadget/function/uvc_configfs.c
@@ -771,6 +771,77 @@ uvcg_format_get_default_color_match(struct config_item *streaming)
return color_match;
}
+static int uvcg_format_allow_link(struct config_item *src, struct config_item *tgt)
+{
+ struct mutex *su_mutex = &src->ci_group->cg_subsys->su_mutex;
+ struct uvcg_color_matching *color_matching_desc;
+ struct config_item *streaming, *color_matching;
+ struct uvcg_format *fmt;
+ int ret = 0;
+
+ mutex_lock(su_mutex);
+
+ streaming = src->ci_parent->ci_parent;
+ color_matching = config_group_find_item(to_config_group(streaming), "color_matching");
+ if (!color_matching || color_matching != tgt->ci_parent) {
+ ret = -EINVAL;
+ goto out_put_cm;
+ }
+
+ fmt = to_uvcg_format(src);
+
+ /*
+ * There's always a color matching descriptor associated with the format
+ * but without a symlink it should only ever be the default one. If it's
+ * not the default, there's already a symlink and we should bail out.
+ */
+ color_matching_desc = uvcg_format_get_default_color_match(streaming);
+ if (fmt->color_matching != color_matching_desc) {
+ ret = -EBUSY;
+ goto out_put_cm;
+ }
+
+ color_matching_desc->refcnt--;
+
+ color_matching_desc = to_uvcg_color_matching(to_config_group(tgt));
+ fmt->color_matching = color_matching_desc;
+ color_matching_desc->refcnt++;
+
+out_put_cm:
+ config_item_put(color_matching);
+ mutex_unlock(su_mutex);
+
+ return ret;
+}
+
+static void uvcg_format_drop_link(struct config_item *src, struct config_item *tgt)
+{
+ struct mutex *su_mutex = &src->ci_group->cg_subsys->su_mutex;
+ struct uvcg_color_matching *color_matching_desc;
+ struct config_item *streaming;
+ struct uvcg_format *fmt;
+
+ mutex_lock(su_mutex);
+
+ color_matching_desc = to_uvcg_color_matching(to_config_group(tgt));
+ color_matching_desc->refcnt--;
+
+ streaming = src->ci_parent->ci_parent;
+ color_matching_desc = uvcg_format_get_default_color_match(streaming);
+
+ fmt = to_uvcg_format(src);
+ fmt->color_matching = color_matching_desc;
+ color_matching_desc->refcnt++;
+
+ mutex_unlock(su_mutex);
+}
+
+static struct configfs_item_operations uvcg_format_item_operations = {
+ .release = uvcg_config_item_release,
+ .allow_link = uvcg_format_allow_link,
+ .drop_link = uvcg_format_drop_link,
+};
+
static ssize_t uvcg_format_bma_controls_show(struct uvcg_format *f, char *page)
{
struct f_uvc_opts *opts;
@@ -1571,7 +1642,7 @@ static struct configfs_attribute *uvcg_uncompressed_attrs[] = {
};
static const struct config_item_type uvcg_uncompressed_type = {
- .ct_item_ops = &uvcg_config_item_ops,
+ .ct_item_ops = &uvcg_format_item_operations,
.ct_group_ops = &uvcg_uncompressed_group_ops,
.ct_attrs = uvcg_uncompressed_attrs,
.ct_owner = THIS_MODULE,
@@ -1767,7 +1838,7 @@ static struct configfs_attribute *uvcg_mjpeg_attrs[] = {
};
static const struct config_item_type uvcg_mjpeg_type = {
- .ct_item_ops = &uvcg_config_item_ops,
+ .ct_item_ops = &uvcg_format_item_operations,
.ct_group_ops = &uvcg_mjpeg_group_ops,
.ct_attrs = uvcg_mjpeg_attrs,
.ct_owner = THIS_MODULE,
@@ -1922,6 +1993,29 @@ static const struct config_item_type uvcg_color_matching_type = {
* streaming/color_matching
*/
+static struct config_group *uvcg_color_matching_make(struct config_group *group,
+ const char *name)
+{
+ struct uvcg_color_matching *color_match;
+
+ color_match = kzalloc(sizeof(*color_match), GFP_KERNEL);
+ if (!color_match)
+ return ERR_PTR(-ENOMEM);
+
+ color_match->desc.bLength = UVC_DT_COLOR_MATCHING_SIZE;
+ color_match->desc.bDescriptorType = USB_DT_CS_INTERFACE;
+ color_match->desc.bDescriptorSubType = UVC_VS_COLORFORMAT;
+
+ config_group_init_type_name(&color_match->group, name,
+ &uvcg_color_matching_type);
+
+ return &color_match->group;
+}
+
+static struct configfs_group_operations uvcg_color_matching_grp_group_ops = {
+ .make_group = uvcg_color_matching_make,
+};
+
static int uvcg_color_matching_create_children(struct config_group *parent)
{
struct uvcg_color_matching *color_match;
@@ -1947,6 +2041,7 @@ static int uvcg_color_matching_create_children(struct config_group *parent)
static const struct uvcg_config_group_type uvcg_color_matching_grp_type = {
.type = {
.ct_item_ops = &uvcg_config_item_ops,
+ .ct_group_ops = &uvcg_color_matching_grp_group_ops,
.ct_owner = THIS_MODULE,
},
.name = "color_matching",
--
2.34.1
