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@xxxxxxxxxxxxxxxx> --- Changes in v2: - New patch drivers/usb/gadget/function/uvc_configfs.c | 60 ++++++++++++++++++++++ drivers/usb/gadget/function/uvc_configfs.h | 1 + 2 files changed, 61 insertions(+) diff --git a/drivers/usb/gadget/function/uvc_configfs.c b/drivers/usb/gadget/function/uvc_configfs.c index da2f70036993..5c51862150c4 100644 --- a/drivers/usb/gadget/function/uvc_configfs.c +++ b/drivers/usb/gadget/function/uvc_configfs.c @@ -1053,8 +1053,68 @@ 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 *strings; + struct uvcg_string *string; + struct config_item *opts_item; + struct f_uvc_opts *opts; + int ret = 0; + + mutex_lock(su_mutex); /* for navigating configfs hierarchy */ + + /* Validate that the target of the link is an entry in strings/<langid> */ + opts_item = src->ci_parent->ci_parent->ci_parent; + + strings = config_group_find_item(to_config_group(opts_item), "strings"); + if (!strings || tgt->ci_parent->ci_parent != strings) { + ret = -EINVAL; + goto put_strings; + } + + string = to_uvcg_string(tgt); + opts = to_f_uvc_opts(opts_item); + + mutex_lock(&opts->lock); + + xu->string_descriptor_index = string->usb_string.id; + + mutex_unlock(&opts->lock); + +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 = { diff --git a/drivers/usb/gadget/function/uvc_configfs.h b/drivers/usb/gadget/function/uvc_configfs.h index a714426a174a..e1308026aed6 100644 --- a/drivers/usb/gadget/function/uvc_configfs.h +++ b/drivers/usb/gadget/function/uvc_configfs.h @@ -183,6 +183,7 @@ 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; }; -- 2.34.1