Currently the string descriptors for the IAD and VideoStreaming Interfaces are hardcoded into f_uvc. Now that we can create arbitrary string descriptors, add a mechanism to define string descriptors for the IAD, VC and VS interfaces by linking to the appropriate directory at function level. Signed-off-by: Daniel Scally <dan.scally@xxxxxxxxxxxxxxxx> --- Changes in v5: - None Changes in v4: - None Changes in v3: - Changed target of link to be within <gadget root>/strings - Dropped the VideoControl description since there's an attribute for that now Changes in v2: - New patch drivers/usb/gadget/function/u_uvc.h | 8 +++ drivers/usb/gadget/function/uvc_configfs.c | 60 ++++++++++++++++++++++ 2 files changed, 68 insertions(+) diff --git a/drivers/usb/gadget/function/u_uvc.h b/drivers/usb/gadget/function/u_uvc.h index 0345b8fc36ff..1ce58f61253c 100644 --- a/drivers/usb/gadget/function/u_uvc.h +++ b/drivers/usb/gadget/function/u_uvc.h @@ -82,6 +82,14 @@ struct f_uvc_opts { struct uvc_descriptor_header **uvc_hs_streaming_cls; struct uvc_descriptor_header **uvc_ss_streaming_cls; + /* + * Indexes into the function's string descriptors allowing users to set + * custom descriptions rather than the hard-coded defaults. + */ + u8 iad_index; + u8 vs0_index; + u8 vs1_index; + /* * Read/write access to configfs attributes is handled by configfs. * diff --git a/drivers/usb/gadget/function/uvc_configfs.c b/drivers/usb/gadget/function/uvc_configfs.c index 3ac27838514c..18c6a1461b7e 100644 --- a/drivers/usb/gadget/function/uvc_configfs.c +++ b/drivers/usb/gadget/function/uvc_configfs.c @@ -3174,8 +3174,68 @@ static void uvc_func_item_release(struct config_item *item) usb_put_function_instance(&opts->func_inst); } +static int uvc_func_allow_link(struct config_item *src, struct config_item *tgt) +{ + struct mutex *su_mutex = &src->ci_group->cg_subsys->su_mutex; + struct gadget_string *string; + struct config_item *strings; + struct f_uvc_opts *opts; + int ret = 0; + + mutex_lock(su_mutex); /* for navigating configfs hierarchy */ + + /* Validate that the target is an entry in strings/<langid> */ + strings = config_group_find_item(to_config_group(src->ci_parent->ci_parent), + "strings"); + if (!strings || tgt->ci_parent->ci_parent != strings) { + ret = -EINVAL; + goto put_strings; + } + + string = to_gadget_string(tgt); + + opts = to_f_uvc_opts(src); + mutex_lock(&opts->lock); + + if (!strcmp(tgt->ci_name, "iad_desc")) + opts->iad_index = string->usb_string.id; + else if (!strcmp(tgt->ci_name, "vs0_desc")) + opts->vs0_index = string->usb_string.id; + else if (!strcmp(tgt->ci_name, "vs1_desc")) + opts->vs1_index = string->usb_string.id; + else + ret = -EINVAL; + + mutex_unlock(&opts->lock); + +put_strings: + config_item_put(strings); + mutex_unlock(su_mutex); + + return ret; +} + +static void uvc_func_drop_link(struct config_item *src, struct config_item *tgt) +{ + struct f_uvc_opts *opts; + + opts = to_f_uvc_opts(src); + mutex_lock(&opts->lock); + + if (!strcmp(tgt->ci_name, "iad_desc")) + opts->iad_index = 0; + else if (!strcmp(tgt->ci_name, "vs0_desc")) + opts->vs0_index = 0; + else if (!strcmp(tgt->ci_name, "vs1_desc")) + opts->vs1_index = 0; + + mutex_unlock(&opts->lock); +} + static struct configfs_item_operations uvc_func_item_ops = { .release = uvc_func_item_release, + .allow_link = uvc_func_allow_link, + .drop_link = uvc_func_drop_link, }; #define UVCG_OPTS_ATTR(cname, aname, limit) \ -- 2.34.1