include/expo.h - filogic/uboot - Gitiles

 /* SPDX-License-Identifier: GPL-2.0+ */
 /*
  * Copyright 2022 Google LLC
  * Written by Simon Glass <sjg@chromium.org>
  */

 #ifndef __EXPO_H
 #define __EXPO_H

 #include <dm/ofnode_decl.h>
 #include <linux/list.h>

 struct udevice;

 /**
  * enum expoact_type - types of actions reported by the expo
  *
  * @EXPOACT_NONE: no action
  * @EXPOACT_POINT_OBJ: object was highlighted (@id indicates which)
  * @EXPOACT_POINT_ITEM: menu item was highlighted (@id indicates which)
  * @EXPOACT_SELECT: menu item was selected (@id indicates which)
  * @EXPOACT_OPEN: menu was opened, so an item can be selected (@id indicates
  * which menu object)
  * @EXPOACT_CLOSE: menu was closed (@id indicates which menu object)
  * @EXPOACT_QUIT: request to exit the menu
  */
 enum expoact_type {
 	EXPOACT_NONE,
 	EXPOACT_POINT_OBJ,
 	EXPOACT_POINT_ITEM,
 	EXPOACT_SELECT,
 	EXPOACT_OPEN,
 	EXPOACT_CLOSE,
 	EXPOACT_QUIT,
 };

 /**
  * struct expo_action - an action report by the expo
  *
  * @type: Action type (EXPOACT_NONE if there is no action)
  * @select: Used for EXPOACT_POINT_ITEM and EXPOACT_SELECT
  * @id: ID number of the object affected.
  */
 struct expo_action {
 	enum expoact_type type;
 	union {
 		struct {
 			int id;
 		} select;
 	};
 };

 /**
  * struct expo_theme - theme for the expo
  *
  * @font_size: Default font size for all text
  * @menu_inset: Inset width (on each side and top/bottom) for menu items
  * @menuitem_gap_y: Gap between menu items in pixels
  */
 struct expo_theme {
 	u32 font_size;
 	u32 menu_inset;
 	u32 menuitem_gap_y;
 };

 /**
  * struct expo - information about an expo
  *
  * A group of scenes which can be presented to the user, typically to obtain
  * input or to make a selection.
  *
  * @name: Name of the expo (allocated)
  * @display: Display to use (`UCLASS_VIDEO`), or NULL to use text mode
  * @cons: Console to use (`UCLASS_VIDEO_CONSOLE`), or NULL to use text mode
  * @scene_id: Current scene ID (0 if none)
  * @next_id: Next ID number to use, for automatic allocation
  * @action: Action selected by user. At present only one is supported, with the
  * type set to EXPOACT_NONE if there is no action
  * @text_mode: true to use text mode for the menu (no vidconsole)
  * @popup: true to use popup menus, instead of showing all items
  * @priv: Private data for the controller
  * @theme: Information about fonts styles, etc.
  * @scene_head: List of scenes
  * @str_head: list of strings
  */
 struct expo {
 	char *name;
 	struct udevice *display;
 	struct udevice *cons;
 	uint scene_id;
 	uint next_id;
 	struct expo_action action;
 	bool text_mode;
 	bool popup;
 	void *priv;
 	struct expo_theme theme;
 	struct list_head scene_head;
 	struct list_head str_head;
 };

 /**
  * struct expo_string - a string that can be used in an expo
  *
  * @id: ID number of the string
  * @str: String
  * @sibling: Node to link this object to its siblings
  */
 struct expo_string {
 	uint id;
 	const char *str;
 	struct list_head sibling;
 };

 /**
  * struct scene - information about a scene in an expo
  *
  * A collection of text/image/menu items in an expo
  *
  * @expo: Expo this scene is part of
  * @name: Name of the scene (allocated)
  * @id: ID number of the scene
  * @title_id: String ID of title of the scene (allocated)
  * @highlight_id: ID of highlighted object, if any
  * @sibling: Node to link this scene to its siblings
  * @obj_head: List of objects in the scene
  */
 struct scene {
 	struct expo *expo;
 	char *name;
 	uint id;
 	uint title_id;
 	uint highlight_id;
 	struct list_head sibling;
 	struct list_head obj_head;
 };

 /**
  * enum scene_obj_t - type of a scene object
  *
  * @SCENEOBJT_NONE: Used to indicate that the type does not matter
  * @SCENEOBJT_IMAGE: Image data to render
  * @SCENEOBJT_TEXT: Text line to render
  * @SCENEOBJT_MENU: Menu containing items the user can select
  */
 enum scene_obj_t {
 	SCENEOBJT_NONE		= 0,
 	SCENEOBJT_IMAGE,
 	SCENEOBJT_TEXT,

 	/* types from here on can be highlighted */
 	SCENEOBJT_MENU,
 };

 /**
  * struct scene_dim - Dimensions of an object
  *
  * @x: x position, in pixels from left side
  * @y: y position, in pixels from top
  * @w: width, in pixels
  * @h: height, in pixels
  */
 struct scene_dim {
 	int x;
 	int y;
 	int w;
 	int h;
 };

 /**
  * enum scene_obj_flags_t - flags for objects
  *
  * @SCENEOF_HIDE: object should be hidden
  * @SCENEOF_POINT: object should be highlighted
  * @SCENEOF_OPEN: object should be opened (e.g. menu is opened so that an option
  * can be selected)
  */
 enum scene_obj_flags_t {
 	SCENEOF_HIDE	= 1 << 0,
 	SCENEOF_POINT	= 1 << 1,
 	SCENEOF_OPEN	= 1 << 2,
 };

 /**
  * struct scene_obj - information about an object in a scene
  *
  * @scene: Scene that this object relates to
  * @name: Name of the object (allocated)
  * @id: ID number of the object
  * @type: Type of this object
  * @dim: Dimensions for this object
  * @flags: Flags for this object
  * @bit_length: Number of bits used for this object in CMOS RAM
  * @start_bit: Start bit to use for this object in CMOS RAM
  * @sibling: Node to link this object to its siblings
  */
 struct scene_obj {
 	struct scene *scene;
 	char *name;
 	uint id;
 	enum scene_obj_t type;
 	struct scene_dim dim;
 	u8 flags;
 	u8 bit_length;
 	u16 start_bit;
 	struct list_head sibling;
 };

 /* object can be highlighted when moving around expo */
 static inline bool scene_obj_can_highlight(const struct scene_obj *obj)
 {
 	return obj->type >= SCENEOBJT_MENU;
 }

 /**
  * struct scene_obj_img - information about an image object in a scene
  *
  * This is a rectangular image which is blitted onto the display
  *
  * @obj: Basic object information
  * @data: Image data in BMP format
  */
 struct scene_obj_img {
 	struct scene_obj obj;
 	char *data;
 };

 /**
  * struct scene_obj_txt - information about a text object in a scene
  *
  * This is a single-line text object
  *
  * @obj: Basic object information
  * @str_id: ID of the text string to display
  * @font_name: Name of font (allocated by caller)
  * @font_size: Nominal size of font in pixels
  */
 struct scene_obj_txt {
 	struct scene_obj obj;
 	uint str_id;
 	const char *font_name;
 	uint font_size;
 };

 /**
  * struct scene_obj_menu - information about a menu object in a scene
  *
  * A menu has a number of items which can be selected by the user
  *
  * It also has:
  *
  * - a text/image object (@pointer_id) which points to the current item
  *   (@cur_item_id)
  *
  * - a preview object which shows an image related to the current item
  *
  * @obj: Basic object information
  * @title_id: ID of the title text, or 0 if none
  * @cur_item_id: ID of the current menu item, or 0 if none
  * @pointer_id: ID of the object pointing to the current selection
  * @item_head: List of items in the menu
  */
 struct scene_obj_menu {
 	struct scene_obj obj;
 	uint title_id;
 	uint cur_item_id;
 	uint pointer_id;
 	struct list_head item_head;
 };

 /**
  * enum scene_menuitem_flags_t - flags for menu items
  *
  * @SCENEMIF_GAP_BEFORE: Add a gap before this item
  */
 enum scene_menuitem_flags_t {
 	SCENEMIF_GAP_BEFORE	= 1 << 0,
 };

 /**
  * struct scene_menitem - a menu item in a menu
  *
  * A menu item has:
  *
  * - text object holding the name (short) and description (can be longer)
  * - a text object holding the keypress
  *
  * @name: Name of the item (this is allocated by this call)
  * @id: ID number of the object
  * @key_id: ID of text object to use as the keypress to show
  * @label_id: ID of text object to use as the label text
  * @desc_id: ID of text object to use as the description text
  * @preview_id: ID of the preview object, or 0 if none
  * @flags: Flags for this item
  * @sibling: Node to link this item to its siblings
  */
 struct scene_menitem {
 	char *name;
 	uint id;
 	uint key_id;
 	uint label_id;
 	uint desc_id;
 	uint preview_id;
 	uint flags;
 	struct list_head sibling;
 };

 /**
  * expo_new() - create a new expo
  *
  * Allocates a new expo
  *
  * @name: Name of expo (this is allocated by this call)
  * @priv: Private data for the controller
  * @expp: Returns a pointer to the new expo on success
  * Returns: 0 if OK, -ENOMEM if out of memory
  */
 int expo_new(const char *name, void *priv, struct expo **expp);

 /**
  * expo_destroy() - Destroy an expo and free all its memory
  *
  * @exp: Expo to destroy
  */
 void expo_destroy(struct expo *exp);

 /**
  * expo_set_dynamic_start() - Set the start of the 'dynamic' IDs
  *
  * It is common for a set of 'static' IDs to be used to refer to objects in the
  * expo. These typically use an enum so that they are defined in sequential
  * order.
  *
  * Dynamic IDs (for objects not in the enum) are intended to be used for
  * objects to which the code does not need to refer. These are ideally located
  * above the static IDs.
  *
  * Use this function to set the start of the dynamic range, making sure that the
  * value is higher than all the statically allocated IDs.
  *
  * @exp: Expo to update
  * @dyn_start: Start ID that expo should use for dynamic allocation
  */
 void expo_set_dynamic_start(struct expo *exp, uint dyn_start);

 /**
  * expo_str() - add a new string to an expo
  *
  * @exp: Expo to update
  * @name: Name to use (this is allocated by this call)
  * @id: ID to use for the new object (0 to allocate one)
  * @str: Pointer to text to display (allocated by caller)
  * Returns: ID number for the object (typically @id), or -ve on error
  */
 int expo_str(struct expo *exp, const char *name, uint id, const char *str);

 /**
  * expo_get_str() - Get a string by ID
  *
  * @exp: Expo to use
  * @id: String ID to look up
  * @returns string, or NULL if not found
  */
 const char *expo_get_str(struct expo *exp, uint id);

 /**
  * expo_set_display() - set the display to use for a expo
  *
  * @exp: Expo to update
  * @dev: Display to use (`UCLASS_VIDEO`), NULL to use text mode
  * Returns: 0 (always)
  */
 int expo_set_display(struct expo *exp, struct udevice *dev);

 /**
  * expo_calc_dims() - Calculate the dimensions of the objects
  *
  * Updates the width and height of all objects based on their contents
  *
  * @exp: Expo to update
  * Returns 0 if OK, -ENOTSUPP if there is no graphical console
  */
 int expo_calc_dims(struct expo *exp);

 /**
  * expo_set_scene_id() - Set the current scene ID
  *
  * @exp: Expo to update
  * @scene_id: New scene ID to use (0 to select no scene)
  * Returns: 0 if OK, -ENOENT if there is no scene with that ID
  */
 int expo_set_scene_id(struct expo *exp, uint scene_id);

 /**
  * expo_first_scene_id() - Get the ID of the first scene
  *
  * @exp: Expo to check
  * Returns: Scene ID of first scene, or -ENOENT if there are no scenes
  */
 int expo_first_scene_id(struct expo *exp);

 /**
  * expo_render() - render the expo on the display / console
  *
  * @exp: Expo to render
  *
  * Returns: 0 if OK, -ECHILD if there is no current scene, -ENOENT if the
  * current scene is not found, other error if something else goes wrong
  */
 int expo_render(struct expo *exp);

 /**
  * expo_set_text_mode() - Controls whether the expo renders in text mode
  *
  * @exp: Expo to update
  * @text_mode: true to use text mode, false to use the console
  */
 void expo_set_text_mode(struct expo *exp, bool text_mode);

 /**
  * scene_new() - create a new scene in a expo
  *
  * The scene is given the ID @id which must be unique across all scenes, objects
  * and items. The expo's @next_id is updated to at least @id + 1
  *
  * @exp: Expo to update
  * @name: Name to use (this is allocated by this call)
  * @id: ID to use for the new scene (0 to allocate one)
  * @scnp: Returns a pointer to the new scene on success
  * Returns: ID number for the scene (typically @id), or -ve on error
  */
 int scene_new(struct expo *exp, const char *name, uint id, struct scene **scnp);

 /**
  * expo_lookup_scene_id() - Look up a scene by ID
  *
  * @exp: Expo to check
  * @scene_id: Scene ID to look up
  * @returns pointer to scene if found, else NULL
  */
 struct scene *expo_lookup_scene_id(struct expo *exp, uint scene_id);

 /**
  * scene_highlight_first() - Highlight the first item in a scene
  *
  * This highlights the first item, so that the user can see that it is pointed
  * to
  *
  * @scn: Scene to update
  */
 void scene_highlight_first(struct scene *scn);

 /**
  * scene_set_highlight_id() - Set the object which is highlighted
  *
  * Sets a new object to highlight in the scene
  *
  * @scn: Scene to update
  * @id: ID of object to highlight
  */
 void scene_set_highlight_id(struct scene *scn, uint id);

 /**
  * scene_set_open() - Set whether an item is open or not
  *
  * @scn: Scene to update
  * @id: ID of object to update
  * @open: true to open the object, false to close it
  * Returns: 0 if OK, -ENOENT if @id is invalid
  */
 int scene_set_open(struct scene *scn, uint id, bool open);

 /**
  * scene_title_set() - set the scene title
  *
  * @scn: Scene to update
  * @title_id: Title ID to set
  * Returns: 0 if OK
  */
 int scene_title_set(struct scene *scn, uint title_id);

 /**
  * scene_obj_count() - Count the number of objects in a scene
  *
  * @scn: Scene to check
  * Returns: number of objects in the scene, 0 if none
  */
 int scene_obj_count(struct scene *scn);

 /**
  * scene_img() - add a new image to a scene
  *
  * @scn: Scene to update
  * @name: Name to use (this is allocated by this call)
  * @id: ID to use for the new object (0 to allocate one)
  * @data: Pointer to image data
  * @imgp: If non-NULL, returns the new object
  * Returns: ID number for the object (typically @id), or -ve on error
  */
 int scene_img(struct scene *scn, const char *name, uint id, char *data,
 	      struct scene_obj_img **imgp);

 /**
  * scene_txt() - add a new text object to a scene
  *
  * @scn: Scene to update
  * @name: Name to use (this is allocated by this call)
  * @id: ID to use for the new object (0 to allocate one)
  * @str_id: ID of the string to use
  * @txtp: If non-NULL, returns the new object
  * Returns: ID number for the object (typically @id), or -ve on error
  */
 int scene_txt(struct scene *scn, const char *name, uint id, uint str_id,
 	      struct scene_obj_txt **txtp);

 /**
  * scene_txt_str() - add a new string to expo and text object to a scene
  *
  * @scn: Scene to update
  * @name: Name to use (this is allocated by this call)
  * @id: ID to use for the new object (0 to allocate one)
  * @str_id: ID of the string to use
  * @str: Pointer to text to display (allocated by caller)
  * @txtp: If non-NULL, returns the new object
  * Returns: ID number for the object (typically @id), or -ve on error
  */
 int scene_txt_str(struct scene *scn, const char *name, uint id, uint str_id,
 		  const char *str, struct scene_obj_txt **txtp);

 /**
  *  scene_menu() - create a menu
  *
  * @scn: Scene to update
  * @name: Name to use (this is allocated by this call)
  * @id: ID to use for the new object (0 to allocate one)
  * @menup: If non-NULL, returns the new object
  * Returns: ID number for the object (typically @id), or -ve on error
  */
 int scene_menu(struct scene *scn, const char *name, uint id,
 	       struct scene_obj_menu **menup);

 /**
  * scene_txt_set_font() - Set the font for an object
  *
  * @scn: Scene to update
  * @id: ID of object to update
  * @font_name: Font name to use (allocated by caller)
  * @font_size: Font size to use (nominal height in pixels)
  */
 int scene_txt_set_font(struct scene *scn, uint id, const char *font_name,
 		       uint font_size);

 /**
  * scene_obj_set_pos() - Set the postion of an object
  *
  * @scn: Scene to update
  * @id: ID of object to update
  * @x: x position, in pixels from left side
  * @y: y position, in pixels from top
  * Returns: 0 if OK, -ENOENT if @id is invalid
  */
 int scene_obj_set_pos(struct scene *scn, uint id, int x, int y);

 /**
  * scene_obj_set_size() - Set the size of an object
  *
  * @scn: Scene to update
  * @id: ID of object to update
  * @w: width in pixels
  * @h: height in pixels
  * Returns: 0 if OK, -ENOENT if @id is invalid
  */
 int scene_obj_set_size(struct scene *scn, uint id, int w, int h);

 /**
  * scene_obj_set_hide() - Set whether an object is hidden
  *
  * The update happens when the expo is next rendered.
  *
  * @scn: Scene to update
  * @id: ID of object to update
  * @hide: true to hide the object, false to show it
  * Returns: 0 if OK, -ENOENT if @id is invalid
  */
 int scene_obj_set_hide(struct scene *scn, uint id, bool hide);

 /**
  * scene_menu_set_title() - Set the title of a menu
  *
  * @scn: Scene to update
  * @id: ID of menu object to update
  * @title_id: ID of text object to use as the title
  * Returns: 0 if OK, -ENOENT if @id is invalid, -EINVAL if @title_id is invalid
  */
 int scene_menu_set_title(struct scene *scn, uint id, uint title_id);

 /**
  * scene_menu_set_pointer() - Set the item pointer for a menu
  *
  * This is a visual indicator of the current item, typically a ">" character
  * which sits next to the current item and moves when the user presses the
  * up/down arrow keys
  *
  * @scn: Scene to update
  * @id: ID of menu object to update
  * @cur_item_id: ID of text or image object to use as a pointer to the current
  * item
  * Returns: 0 if OK, -ENOENT if @id is invalid, -EINVAL if @cur_item_id is invalid
  */
 int scene_menu_set_pointer(struct scene *scn, uint id, uint cur_item_id);

 /**
  * scene_obj_get_hw() - Get width and height of an object in a scene
  *
  * @scn: Scene to check
  * @id: ID of menu object to check
  * @widthp: If non-NULL, returns width of object in pixels
  * Returns: Height of object in pixels
  */
 int scene_obj_get_hw(struct scene *scn, uint id, int *widthp);

 /**
  * scene_menuitem() - Add an item to a menu
  *
  * @scn: Scene to update
  * @menu_id: ID of menu object to update
  * @name: Name to use (this is allocated by this call)
  * @id: ID to use for the new object (0 to allocate one)
  * @key_id: ID of text object to use as the keypress to show
  * @label_id: ID of text object to use as the label text
  * @desc_id: ID of text object to use as the description text
  * @preview_id: ID of object to use as the preview (text or image)
  * @flags: Flags for this item (enum scene_menuitem_flags_t)
  * @itemp: If non-NULL, returns the new object
  * Returns: ID number for the item (typically @id), or -ve on error
  */
 int scene_menuitem(struct scene *scn, uint menu_id, const char *name, uint id,
 		   uint key_id, uint label_id, uint desc_id, uint preview_id,
 		   uint flags, struct scene_menitem **itemp);

 /**
  * scene_arrange() - Arrange the scene to deal with object sizes
  *
  * Updates any menus in the scene so that their objects are in the right place.
  *
  * @scn: Scene to arrange
  * Returns: 0 if OK, -ve on error
  */
 int scene_arrange(struct scene *scn);

 /**
  * expo_send_key() - set a keypress to the expo
  *
  * @exp: Expo to receive the key
  * @key: Key to send (ASCII or enum bootmenu_key)
  * Returns: 0 if OK, -ECHILD if there is no current scene
  */
 int expo_send_key(struct expo *exp, int key);

 /**
  * expo_action_get() - read user input from the expo
  *
  * @exp: Expo to check
  * @act: Returns action
  * Returns: 0 if OK, -EAGAIN if there was no action to return
  */
 int expo_action_get(struct expo *exp, struct expo_action *act);

 /**
  * expo_apply_theme() - Apply a theme to an expo
  *
  * @exp: Expo to update
  * @node: Node containing the theme
  */
 int expo_apply_theme(struct expo *exp, ofnode node);

 /**
  * expo_build() - Build an expo from an FDT description
  *
  * Build a complete expo from a description in the provided devicetree.
  *
  * See doc/develop/expo.rst for a description of the format
  *
  * @root: Root node for expo description
  * @expp: Returns the new expo
  * Returns: 0 if OK, -ENOMEM if out of memory, -EINVAL if there is a format
  * error, -ENOENT if there is a references to a non-existent string
  */
 int expo_build(ofnode root, struct expo **expp);

 #endif /*__EXPO_H */
	/* SPDX-License-Identifier: GPL-2.0+ */
	/*
	* Copyright 2022 Google LLC
	* Written by Simon Glass <sjg@chromium.org>
	*/

	#ifndef __EXPO_H
	#define __EXPO_H

	#include <dm/ofnode_decl.h>
	#include <linux/list.h>

	struct udevice;

	/**
	* enum expoact_type - types of actions reported by the expo
	*
	* @EXPOACT_NONE: no action
	* @EXPOACT_POINT_OBJ: object was highlighted (@id indicates which)
	* @EXPOACT_POINT_ITEM: menu item was highlighted (@id indicates which)
	* @EXPOACT_SELECT: menu item was selected (@id indicates which)
	* @EXPOACT_OPEN: menu was opened, so an item can be selected (@id indicates
	* which menu object)
	* @EXPOACT_CLOSE: menu was closed (@id indicates which menu object)
	* @EXPOACT_QUIT: request to exit the menu
	*/
	enum expoact_type {
	EXPOACT_NONE,
	EXPOACT_POINT_OBJ,
	EXPOACT_POINT_ITEM,
	EXPOACT_SELECT,
	EXPOACT_OPEN,
	EXPOACT_CLOSE,
	EXPOACT_QUIT,
	};

	/**
	* struct expo_action - an action report by the expo
	*
	* @type: Action type (EXPOACT_NONE if there is no action)
	* @select: Used for EXPOACT_POINT_ITEM and EXPOACT_SELECT
	* @id: ID number of the object affected.
	*/
	struct expo_action {
	enum expoact_type type;
	union {
	struct {
	int id;
	} select;
	};
	};

	/**
	* struct expo_theme - theme for the expo
	*
	* @font_size: Default font size for all text
	* @menu_inset: Inset width (on each side and top/bottom) for menu items
	* @menuitem_gap_y: Gap between menu items in pixels
	*/
	struct expo_theme {
	u32 font_size;
	u32 menu_inset;
	u32 menuitem_gap_y;
	};

	/**
	* struct expo - information about an expo
	*
	* A group of scenes which can be presented to the user, typically to obtain
	* input or to make a selection.
	*
	* @name: Name of the expo (allocated)
	* @display: Display to use (`UCLASS_VIDEO`), or NULL to use text mode
	* @cons: Console to use (`UCLASS_VIDEO_CONSOLE`), or NULL to use text mode
	* @scene_id: Current scene ID (0 if none)
	* @next_id: Next ID number to use, for automatic allocation
	* @action: Action selected by user. At present only one is supported, with the
	* type set to EXPOACT_NONE if there is no action
	* @text_mode: true to use text mode for the menu (no vidconsole)
	* @popup: true to use popup menus, instead of showing all items
	* @priv: Private data for the controller
	* @theme: Information about fonts styles, etc.
	* @scene_head: List of scenes
	* @str_head: list of strings
	*/
	struct expo {
	char *name;
	struct udevice *display;
	struct udevice *cons;
	uint scene_id;
	uint next_id;
	struct expo_action action;
	bool text_mode;
	bool popup;
	void *priv;
	struct expo_theme theme;
	struct list_head scene_head;
	struct list_head str_head;
	};

	/**
	* struct expo_string - a string that can be used in an expo
	*
	* @id: ID number of the string
	* @str: String
	* @sibling: Node to link this object to its siblings
	*/
	struct expo_string {
	uint id;
	const char *str;
	struct list_head sibling;
	};

	/**
	* struct scene - information about a scene in an expo
	*
	* A collection of text/image/menu items in an expo
	*
	* @expo: Expo this scene is part of
	* @name: Name of the scene (allocated)
	* @id: ID number of the scene
	* @title_id: String ID of title of the scene (allocated)
	* @highlight_id: ID of highlighted object, if any
	* @sibling: Node to link this scene to its siblings
	* @obj_head: List of objects in the scene
	*/
	struct scene {
	struct expo *expo;
	char *name;
	uint id;
	uint title_id;
	uint highlight_id;
	struct list_head sibling;
	struct list_head obj_head;
	};

	/**
	* enum scene_obj_t - type of a scene object
	*
	* @SCENEOBJT_NONE: Used to indicate that the type does not matter
	* @SCENEOBJT_IMAGE: Image data to render
	* @SCENEOBJT_TEXT: Text line to render
	* @SCENEOBJT_MENU: Menu containing items the user can select
	*/
	enum scene_obj_t {
	SCENEOBJT_NONE = 0,
	SCENEOBJT_IMAGE,
	SCENEOBJT_TEXT,

	/* types from here on can be highlighted */
	SCENEOBJT_MENU,
	};

	/**
	* struct scene_dim - Dimensions of an object
	*
	* @x: x position, in pixels from left side
	* @y: y position, in pixels from top
	* @w: width, in pixels
	* @h: height, in pixels
	*/
	struct scene_dim {
	int x;
	int y;
	int w;
	int h;
	};

	/**
	* enum scene_obj_flags_t - flags for objects
	*
	* @SCENEOF_HIDE: object should be hidden
	* @SCENEOF_POINT: object should be highlighted
	* @SCENEOF_OPEN: object should be opened (e.g. menu is opened so that an option
	* can be selected)
	*/
	enum scene_obj_flags_t {
	SCENEOF_HIDE = 1 << 0,
	SCENEOF_POINT = 1 << 1,
	SCENEOF_OPEN = 1 << 2,
	};

	/**
	* struct scene_obj - information about an object in a scene
	*
	* @scene: Scene that this object relates to
	* @name: Name of the object (allocated)
	* @id: ID number of the object
	* @type: Type of this object
	* @dim: Dimensions for this object
	* @flags: Flags for this object
	* @bit_length: Number of bits used for this object in CMOS RAM
	* @start_bit: Start bit to use for this object in CMOS RAM
	* @sibling: Node to link this object to its siblings
	*/
	struct scene_obj {
	struct scene *scene;
	char *name;
	uint id;
	enum scene_obj_t type;
	struct scene_dim dim;
	u8 flags;
	u8 bit_length;
	u16 start_bit;
	struct list_head sibling;
	};

	/* object can be highlighted when moving around expo */
	static inline bool scene_obj_can_highlight(const struct scene_obj *obj)
	{
	return obj->type >= SCENEOBJT_MENU;
	}

	/**
	* struct scene_obj_img - information about an image object in a scene
	*
	* This is a rectangular image which is blitted onto the display
	*
	* @obj: Basic object information
	* @data: Image data in BMP format
	*/
	struct scene_obj_img {
	struct scene_obj obj;
	char *data;
	};

	/**
	* struct scene_obj_txt - information about a text object in a scene
	*
	* This is a single-line text object
	*
	* @obj: Basic object information
	* @str_id: ID of the text string to display
	* @font_name: Name of font (allocated by caller)
	* @font_size: Nominal size of font in pixels
	*/
	struct scene_obj_txt {
	struct scene_obj obj;
	uint str_id;
	const char *font_name;
	uint font_size;
	};

	/**
	* struct scene_obj_menu - information about a menu object in a scene
	*
	* A menu has a number of items which can be selected by the user
	*
	* It also has:
	*
	* - a text/image object (@pointer_id) which points to the current item
	* (@cur_item_id)
	*
	* - a preview object which shows an image related to the current item
	*
	* @obj: Basic object information
	* @title_id: ID of the title text, or 0 if none
	* @cur_item_id: ID of the current menu item, or 0 if none
	* @pointer_id: ID of the object pointing to the current selection
	* @item_head: List of items in the menu
	*/
	struct scene_obj_menu {
	struct scene_obj obj;
	uint title_id;
	uint cur_item_id;
	uint pointer_id;
	struct list_head item_head;
	};

	/**
	* enum scene_menuitem_flags_t - flags for menu items
	*
	* @SCENEMIF_GAP_BEFORE: Add a gap before this item
	*/
	enum scene_menuitem_flags_t {
	SCENEMIF_GAP_BEFORE = 1 << 0,
	};

	/**
	* struct scene_menitem - a menu item in a menu
	*
	* A menu item has:
	*
	* - text object holding the name (short) and description (can be longer)
	* - a text object holding the keypress
	*
	* @name: Name of the item (this is allocated by this call)
	* @id: ID number of the object
	* @key_id: ID of text object to use as the keypress to show
	* @label_id: ID of text object to use as the label text
	* @desc_id: ID of text object to use as the description text
	* @preview_id: ID of the preview object, or 0 if none
	* @flags: Flags for this item
	* @sibling: Node to link this item to its siblings
	*/
	struct scene_menitem {
	char *name;
	uint id;
	uint key_id;
	uint label_id;
	uint desc_id;
	uint preview_id;
	uint flags;
	struct list_head sibling;
	};

	/**
	* expo_new() - create a new expo
	*
	* Allocates a new expo
	*
	* @name: Name of expo (this is allocated by this call)
	* @priv: Private data for the controller
	* @expp: Returns a pointer to the new expo on success
	* Returns: 0 if OK, -ENOMEM if out of memory
	*/
	int expo_new(const char name, void priv, struct expo **expp);

	/**
	* expo_destroy() - Destroy an expo and free all its memory
	*
	* @exp: Expo to destroy
	*/
	void expo_destroy(struct expo *exp);

	/**
	* expo_set_dynamic_start() - Set the start of the 'dynamic' IDs
	*
	* It is common for a set of 'static' IDs to be used to refer to objects in the
	* expo. These typically use an enum so that they are defined in sequential
	* order.
	*
	* Dynamic IDs (for objects not in the enum) are intended to be used for
	* objects to which the code does not need to refer. These are ideally located
	* above the static IDs.
	*
	* Use this function to set the start of the dynamic range, making sure that the
	* value is higher than all the statically allocated IDs.
	*
	* @exp: Expo to update
	* @dyn_start: Start ID that expo should use for dynamic allocation
	*/
	void expo_set_dynamic_start(struct expo *exp, uint dyn_start);

	/**
	* expo_str() - add a new string to an expo
	*
	* @exp: Expo to update
	* @name: Name to use (this is allocated by this call)
	* @id: ID to use for the new object (0 to allocate one)
	* @str: Pointer to text to display (allocated by caller)
	* Returns: ID number for the object (typically @id), or -ve on error
	*/
	int expo_str(struct expo exp, const char name, uint id, const char *str);

	/**
	* expo_get_str() - Get a string by ID
	*
	* @exp: Expo to use
	* @id: String ID to look up
	* @returns string, or NULL if not found
	*/
	const char expo_get_str(struct expo exp, uint id);

	/**
	* expo_set_display() - set the display to use for a expo
	*
	* @exp: Expo to update
	* @dev: Display to use (`UCLASS_VIDEO`), NULL to use text mode
	* Returns: 0 (always)
	*/
	int expo_set_display(struct expo exp, struct udevice dev);

	/**
	* expo_calc_dims() - Calculate the dimensions of the objects
	*
	* Updates the width and height of all objects based on their contents
	*
	* @exp: Expo to update
	* Returns 0 if OK, -ENOTSUPP if there is no graphical console
	*/
	int expo_calc_dims(struct expo *exp);

	/**
	* expo_set_scene_id() - Set the current scene ID
	*
	* @exp: Expo to update
	* @scene_id: New scene ID to use (0 to select no scene)
	* Returns: 0 if OK, -ENOENT if there is no scene with that ID
	*/
	int expo_set_scene_id(struct expo *exp, uint scene_id);

	/**
	* expo_first_scene_id() - Get the ID of the first scene
	*
	* @exp: Expo to check
	* Returns: Scene ID of first scene, or -ENOENT if there are no scenes
	*/
	int expo_first_scene_id(struct expo *exp);

	/**
	* expo_render() - render the expo on the display / console
	*
	* @exp: Expo to render
	*
	* Returns: 0 if OK, -ECHILD if there is no current scene, -ENOENT if the
	* current scene is not found, other error if something else goes wrong
	*/
	int expo_render(struct expo *exp);

	/**
	* expo_set_text_mode() - Controls whether the expo renders in text mode
	*
	* @exp: Expo to update
	* @text_mode: true to use text mode, false to use the console
	*/
	void expo_set_text_mode(struct expo *exp, bool text_mode);

	/**
	* scene_new() - create a new scene in a expo
	*
	* The scene is given the ID @id which must be unique across all scenes, objects
	* and items. The expo's @next_id is updated to at least @id + 1
	*
	* @exp: Expo to update
	* @name: Name to use (this is allocated by this call)
	* @id: ID to use for the new scene (0 to allocate one)
	* @scnp: Returns a pointer to the new scene on success
	* Returns: ID number for the scene (typically @id), or -ve on error
	*/
	int scene_new(struct expo exp, const char name, uint id, struct scene **scnp);

	/**
	* expo_lookup_scene_id() - Look up a scene by ID
	*
	* @exp: Expo to check
	* @scene_id: Scene ID to look up
	* @returns pointer to scene if found, else NULL
	*/
	struct scene expo_lookup_scene_id(struct expo exp, uint scene_id);

	/**
	* scene_highlight_first() - Highlight the first item in a scene
	*
	* This highlights the first item, so that the user can see that it is pointed
	* to
	*
	* @scn: Scene to update
	*/
	void scene_highlight_first(struct scene *scn);

	/**
	* scene_set_highlight_id() - Set the object which is highlighted
	*
	* Sets a new object to highlight in the scene
	*
	* @scn: Scene to update
	* @id: ID of object to highlight
	*/
	void scene_set_highlight_id(struct scene *scn, uint id);

	/**
	* scene_set_open() - Set whether an item is open or not
	*
	* @scn: Scene to update
	* @id: ID of object to update
	* @open: true to open the object, false to close it
	* Returns: 0 if OK, -ENOENT if @id is invalid
	*/
	int scene_set_open(struct scene *scn, uint id, bool open);

	/**
	* scene_title_set() - set the scene title
	*
	* @scn: Scene to update
	* @title_id: Title ID to set
	* Returns: 0 if OK
	*/
	int scene_title_set(struct scene *scn, uint title_id);

	/**
	* scene_obj_count() - Count the number of objects in a scene
	*
	* @scn: Scene to check
	* Returns: number of objects in the scene, 0 if none
	*/
	int scene_obj_count(struct scene *scn);

	/**
	* scene_img() - add a new image to a scene
	*
	* @scn: Scene to update
	* @name: Name to use (this is allocated by this call)
	* @id: ID to use for the new object (0 to allocate one)
	* @data: Pointer to image data
	* @imgp: If non-NULL, returns the new object
	* Returns: ID number for the object (typically @id), or -ve on error
	*/
	int scene_img(struct scene scn, const char name, uint id, char *data,
	struct scene_obj_img **imgp);

	/**
	* scene_txt() - add a new text object to a scene
	*
	* @scn: Scene to update
	* @name: Name to use (this is allocated by this call)
	* @id: ID to use for the new object (0 to allocate one)
	* @str_id: ID of the string to use
	* @txtp: If non-NULL, returns the new object
	* Returns: ID number for the object (typically @id), or -ve on error
	*/
	int scene_txt(struct scene scn, const char name, uint id, uint str_id,
	struct scene_obj_txt **txtp);

	/**
	* scene_txt_str() - add a new string to expo and text object to a scene
	*
	* @scn: Scene to update
	* @name: Name to use (this is allocated by this call)
	* @id: ID to use for the new object (0 to allocate one)
	* @str_id: ID of the string to use
	* @str: Pointer to text to display (allocated by caller)
	* @txtp: If non-NULL, returns the new object
	* Returns: ID number for the object (typically @id), or -ve on error
	*/
	int scene_txt_str(struct scene scn, const char name, uint id, uint str_id,
	const char str, struct scene_obj_txt *txtp);

	/**
	* scene_menu() - create a menu
	*
	* @scn: Scene to update
	* @name: Name to use (this is allocated by this call)
	* @id: ID to use for the new object (0 to allocate one)
	* @menup: If non-NULL, returns the new object
	* Returns: ID number for the object (typically @id), or -ve on error
	*/
	int scene_menu(struct scene scn, const char name, uint id,
	struct scene_obj_menu **menup);

	/**
	* scene_txt_set_font() - Set the font for an object
	*
	* @scn: Scene to update
	* @id: ID of object to update
	* @font_name: Font name to use (allocated by caller)
	* @font_size: Font size to use (nominal height in pixels)
	*/
	int scene_txt_set_font(struct scene scn, uint id, const char font_name,
	uint font_size);

	/**
	* scene_obj_set_pos() - Set the postion of an object
	*
	* @scn: Scene to update
	* @id: ID of object to update
	* @x: x position, in pixels from left side
	* @y: y position, in pixels from top
	* Returns: 0 if OK, -ENOENT if @id is invalid
	*/
	int scene_obj_set_pos(struct scene *scn, uint id, int x, int y);

	/**
	* scene_obj_set_size() - Set the size of an object
	*
	* @scn: Scene to update
	* @id: ID of object to update
	* @w: width in pixels
	* @h: height in pixels
	* Returns: 0 if OK, -ENOENT if @id is invalid
	*/
	int scene_obj_set_size(struct scene *scn, uint id, int w, int h);

	/**
	* scene_obj_set_hide() - Set whether an object is hidden
	*
	* The update happens when the expo is next rendered.
	*
	* @scn: Scene to update
	* @id: ID of object to update
	* @hide: true to hide the object, false to show it
	* Returns: 0 if OK, -ENOENT if @id is invalid
	*/
	int scene_obj_set_hide(struct scene *scn, uint id, bool hide);

	/**
	* scene_menu_set_title() - Set the title of a menu
	*
	* @scn: Scene to update
	* @id: ID of menu object to update
	* @title_id: ID of text object to use as the title
	* Returns: 0 if OK, -ENOENT if @id is invalid, -EINVAL if @title_id is invalid
	*/
	int scene_menu_set_title(struct scene *scn, uint id, uint title_id);

	/**
	* scene_menu_set_pointer() - Set the item pointer for a menu
	*
	* This is a visual indicator of the current item, typically a ">" character
	* which sits next to the current item and moves when the user presses the
	* up/down arrow keys
	*
	* @scn: Scene to update
	* @id: ID of menu object to update
	* @cur_item_id: ID of text or image object to use as a pointer to the current
	* item
	* Returns: 0 if OK, -ENOENT if @id is invalid, -EINVAL if @cur_item_id is invalid
	*/
	int scene_menu_set_pointer(struct scene *scn, uint id, uint cur_item_id);

	/**
	* scene_obj_get_hw() - Get width and height of an object in a scene
	*
	* @scn: Scene to check
	* @id: ID of menu object to check
	* @widthp: If non-NULL, returns width of object in pixels
	* Returns: Height of object in pixels
	*/
	int scene_obj_get_hw(struct scene scn, uint id, int widthp);

	/**
	* scene_menuitem() - Add an item to a menu
	*
	* @scn: Scene to update
	* @menu_id: ID of menu object to update
	* @name: Name to use (this is allocated by this call)
	* @id: ID to use for the new object (0 to allocate one)
	* @key_id: ID of text object to use as the keypress to show
	* @label_id: ID of text object to use as the label text
	* @desc_id: ID of text object to use as the description text
	* @preview_id: ID of object to use as the preview (text or image)
	* @flags: Flags for this item (enum scene_menuitem_flags_t)
	* @itemp: If non-NULL, returns the new object
	* Returns: ID number for the item (typically @id), or -ve on error
	*/
	int scene_menuitem(struct scene scn, uint menu_id, const char name, uint id,
	uint key_id, uint label_id, uint desc_id, uint preview_id,
	uint flags, struct scene_menitem **itemp);

	/**
	* scene_arrange() - Arrange the scene to deal with object sizes
	*
	* Updates any menus in the scene so that their objects are in the right place.
	*
	* @scn: Scene to arrange
	* Returns: 0 if OK, -ve on error
	*/
	int scene_arrange(struct scene *scn);

	/**
	* expo_send_key() - set a keypress to the expo
	*
	* @exp: Expo to receive the key
	* @key: Key to send (ASCII or enum bootmenu_key)
	* Returns: 0 if OK, -ECHILD if there is no current scene
	*/
	int expo_send_key(struct expo *exp, int key);

	/**
	* expo_action_get() - read user input from the expo
	*
	* @exp: Expo to check
	* @act: Returns action
	* Returns: 0 if OK, -EAGAIN if there was no action to return
	*/
	int expo_action_get(struct expo exp, struct expo_action act);

	/**
	* expo_apply_theme() - Apply a theme to an expo
	*
	* @exp: Expo to update
	* @node: Node containing the theme
	*/
	int expo_apply_theme(struct expo *exp, ofnode node);

	/**
	* expo_build() - Build an expo from an FDT description
	*
	* Build a complete expo from a description in the provided devicetree.
	*
	* See doc/develop/expo.rst for a description of the format
	*
	* @root: Root node for expo description
	* @expp: Returns the new expo
	* Returns: 0 if OK, -ENOMEM if out of memory, -EINVAL if there is a format
	* error, -ENOENT if there is a references to a non-existent string
	*/
	int expo_build(ofnode root, struct expo **expp);

	#endif /__EXPO_H /