Quoting Daniel Scally (2022-12-13 08:37:32)
> Color matching descriptors are meant to be a per-format piece of data
> and we need to be able to support different descriptors for different
> formats. As a preliminary step towards that goal, switch the default
> color matching configfs functionality to point to an instance of a
> new struct uvcg_cmd (for "color matching descriptor"). Use the same
Hrm .. I can't see 'cmd' and not think 'command' ... but longer names
are longer ...
> default values for its attributes as the currently hard-coded ones so
> that the interface to userspace is consistent.
>
> Signed-off-by: Daniel Scally <dan.scally@xxxxxxxxxxxxxxxx>
> ---
> drivers/usb/gadget/function/uvc_configfs.c | 55 ++++++++++++++++------
> drivers/usb/gadget/function/uvc_configfs.h | 8 ++++
> 2 files changed, 49 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/usb/gadget/function/uvc_configfs.c b/drivers/usb/gadget/function/uvc_configfs.c
> index 26d092790f12..9918e7b6a023 100644
> --- a/drivers/usb/gadget/function/uvc_configfs.c
> +++ b/drivers/usb/gadget/function/uvc_configfs.c
> @@ -1788,20 +1788,19 @@ static ssize_t uvcg_color_matching_##cname##_show( \
> struct config_item *item, char *page) \
> { \
> struct config_group *group = to_config_group(item); \
> + struct uvcg_cmd *cmd = to_uvcg_cmd(group); \
> struct f_uvc_opts *opts; \
> struct config_item *opts_item; \
> struct mutex *su_mutex = &group->cg_subsys->su_mutex; \
> - struct uvc_color_matching_descriptor *cd; \
> int result; \
> \
> mutex_lock(su_mutex); /* for navigating configfs hierarchy */ \
> \
> opts_item = group->cg_item.ci_parent->ci_parent->ci_parent; \
> opts = to_f_uvc_opts(opts_item); \
> - cd = &opts->uvc_color_matching; \
> \
> mutex_lock(&opts->lock); \
> - result = sprintf(page, "%u\n", le##bits##_to_cpu(cd->aname)); \
> + result = sprintf(page, "%u\n", le##bits##_to_cpu(cmd->desc.aname));\
> mutex_unlock(&opts->lock); \
> \
> mutex_unlock(su_mutex); \
> @@ -1823,29 +1822,57 @@ static struct configfs_attribute *uvcg_color_matching_attrs[] = {
> NULL,
> };
>
> -static const struct uvcg_config_group_type uvcg_color_matching_type = {
> - .type = {
> - .ct_item_ops = &uvcg_config_item_ops,
> - .ct_attrs = uvcg_color_matching_attrs,
> - .ct_owner = THIS_MODULE,
> - },
> - .name = "default",
> +static void uvcg_color_matching_release(struct config_item *item)
> +{
> + struct uvcg_cmd *cmd;
> +
> + cmd = to_uvcg_cmd(to_config_group(item));
> + kfree(cmd);
> +}
> +
> +static struct configfs_item_operations uvcg_color_matching_item_ops = {
> + .release = uvcg_color_matching_release,
> +};
> +
> +static const struct config_item_type uvcg_color_matching_type = {
> + .ct_item_ops = &uvcg_color_matching_item_ops,
> + .ct_attrs = uvcg_color_matching_attrs,
> + .ct_owner = THIS_MODULE,
> };
>
> /* -----------------------------------------------------------------------------
> * streaming/color_matching
> */
>
> +static int uvcg_color_matching_create_children(struct config_group *parent)
> +{
> + struct uvcg_cmd *cmd;
> +
> + cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
> + if (!cmd)
> + return -ENOMEM;
> +
> + cmd->desc.bLength = UVC_DT_COLOR_MATCHING_SIZE;
> + cmd->desc.bDescriptorType = USB_DT_CS_INTERFACE;
> + cmd->desc.bDescriptorSubType = UVC_VS_COLORFORMAT;
> + cmd->desc.bColorPrimaries = 1;
> + cmd->desc.bTransferCharacteristics = 1;
> + cmd->desc.bMatrixCoefficients = 4;
I realise these values were taken directly as existing code, but
particularly in regards to how these values will be set from userspace -
is it easy enough to have some common definitions in a preceeding patch
that state the supported values here from the spec, to avoid 'magic
values' here ...
A header with defines or an enum isn't going to be usable from a bash
script configuring configfs, but at least a compiled program could use
the definitions.
> +
> + config_group_init_type_name(&cmd->group, "default",
> + &uvcg_color_matching_type);
> + configfs_add_default_group(&cmd->group, parent);
> +
> + return 0;
> +}
> +
> static const struct uvcg_config_group_type uvcg_color_matching_grp_type = {
> .type = {
> .ct_item_ops = &uvcg_config_item_ops,
> .ct_owner = THIS_MODULE,
> },
> .name = "color_matching",
> - .children = (const struct uvcg_config_group_type*[]) {
> - &uvcg_color_matching_type,
> - NULL,
> - },
> + .create_children = uvcg_color_matching_create_children,
> };
>
> /* -----------------------------------------------------------------------------
> diff --git a/drivers/usb/gadget/function/uvc_configfs.h b/drivers/usb/gadget/function/uvc_configfs.h
> index ad2ec8c4c78c..f990739838d5 100644
> --- a/drivers/usb/gadget/function/uvc_configfs.h
> +++ b/drivers/usb/gadget/function/uvc_configfs.h
> @@ -37,6 +37,14 @@ static inline struct uvcg_control_header *to_uvcg_control_header(struct config_i
> return container_of(item, struct uvcg_control_header, item);
> }
>
> +struct uvcg_cmd {
> + struct config_group group;
> + struct uvc_color_matching_descriptor desc;
> +};
> +
> +#define to_uvcg_cmd(group_ptr) \
> +container_of(group_ptr, struct uvcg_cmd, group)
> +
> enum uvcg_format_type {
> UVCG_UNCOMPRESSED = 0,
> UVCG_MJPEG,
> --
> 2.34.1
>
