@@ -1064,8 +1064,60 @@ static void uvcg_extension_release(struct config_item *item)
kfree(xu);
}
+static int uvcg_extension_allow_link(struct config_item *src, struct config_item *tgt)
+{
+ struct mutex *su_mutex = &src->ci_group->cg_subsys->su_mutex;
+ struct uvcg_extension *xu = to_uvcg_extension(src);
+ struct config_item *gadget_item;
+ struct gadget_string *string;
+ struct config_item *strings;
+ int ret = 0;
+
+ mutex_lock(su_mutex); /* for navigating configfs hierarchy */
+
+ /* Validate that the target of the link is an entry in strings/<langid> */
+ gadget_item = src->ci_parent->ci_parent->ci_parent->ci_parent->ci_parent;
+ strings = config_group_find_item(to_config_group(gadget_item), "strings");
+ if (!strings || tgt->ci_parent->ci_parent != strings) {
+ ret = -EINVAL;
+ goto put_strings;
+ }
+
+ string = to_gadget_string(tgt);
+ xu->string_descriptor_index = string->usb_string.id;
+
+put_strings:
+ config_item_put(strings);
+ mutex_unlock(su_mutex);
+
+ return ret;
+}
+
+static void uvcg_extension_drop_link(struct config_item *src, struct config_item *tgt)
+{
+ struct mutex *su_mutex = &src->ci_group->cg_subsys->su_mutex;
+ struct uvcg_extension *xu = to_uvcg_extension(src);
+ struct config_item *opts_item;
+ struct f_uvc_opts *opts;
+
+ mutex_lock(su_mutex); /* for navigating configfs hierarchy */
+
+ opts_item = src->ci_parent->ci_parent->ci_parent;
+ opts = to_f_uvc_opts(opts_item);
+
+ mutex_lock(&opts->lock);
+
+ xu->string_descriptor_index = 0;
+
+ mutex_unlock(&opts->lock);
+
+ mutex_unlock(su_mutex);
+}
+
static struct configfs_item_operations uvcg_extension_item_ops = {
.release = uvcg_extension_release,
+ .allow_link = uvcg_extension_allow_link,
+ .drop_link = uvcg_extension_drop_link,
};
static const struct config_item_type uvcg_extension_type = {
@@ -163,6 +163,7 @@ struct uvcg_extension_unit_descriptor {
struct uvcg_extension {
struct config_item item;
struct list_head list;
+ u8 string_descriptor_index;
struct uvcg_extension_unit_descriptor desc;
};
Add .allow_link() and .drop_link() callbacks to allow users to link an extension unit descriptor to a string descriptor. Signed-off-by: Daniel Scally <dan.scally@ideasonboard.com> --- Changes in v5: - None Changes in v4: - None Changes in v3: - Changed the target of the links to in <gadget root>/strings Changes in v2: - New patch drivers/usb/gadget/function/uvc_configfs.c | 52 ++++++++++++++++++++++ drivers/usb/gadget/function/uvc_configfs.h | 1 + 2 files changed, 53 insertions(+)