1 /* SPDX-License-Identifier: GPL-2.0-or-later */ 2 /* 3 * Character line display core support 4 * 5 * Copyright (C) 2016 Imagination Technologies 6 * Author: Paul Burton <paul.burton@mips.com> 7 * 8 * Copyright (C) 2021 Glider bv 9 * Copyright (C) 2025 Jean-François Lessard 10 */ 11 12 #ifndef _LINEDISP_H 13 #define _LINEDISP_H 14 15 #include <linux/device.h> 16 #include <linux/timer_types.h> 17 18 #include <linux/map_to_7segment.h> 19 #include <linux/map_to_14segment.h> 20 21 struct linedisp; 22 23 /** 24 * enum linedisp_map_type - type of the character mapping 25 * @LINEDISP_MAP_SEG7: Map characters to 7 segment display 26 * @LINEDISP_MAP_SEG14: Map characters to 14 segment display 27 */ 28 enum linedisp_map_type { 29 LINEDISP_MAP_SEG7, 30 LINEDISP_MAP_SEG14, 31 }; 32 33 /** 34 * struct linedisp_map - character mapping 35 * @type: type of the character mapping 36 * @map: conversion character mapping 37 * @size: size of the @map 38 */ 39 struct linedisp_map { 40 enum linedisp_map_type type; 41 union { 42 struct seg7_conversion_map seg7; 43 struct seg14_conversion_map seg14; 44 } map; 45 unsigned int size; 46 }; 47 48 /** 49 * struct linedisp_ops - character line display operations 50 * @get_map_type: Function called to get the character mapping, if required 51 * @update: Function called to update the display. This must not sleep! 52 */ 53 struct linedisp_ops { 54 int (*get_map_type)(struct linedisp *linedisp); 55 void (*update)(struct linedisp *linedisp); 56 }; 57 58 /** 59 * struct linedisp - character line display private data structure 60 * @dev: the line display device 61 * @timer: timer used to implement scrolling 62 * @ops: character line display operations 63 * @buf: pointer to the buffer for the string currently displayed 64 * @message: the full message to display or scroll on the display 65 * @num_chars: the number of characters that can be displayed 66 * @message_len: the length of the @message string 67 * @scroll_pos: index of the first character of @message currently displayed 68 * @scroll_rate: scroll interval in jiffies 69 * @id: instance id of this display 70 */ 71 struct linedisp { 72 struct device dev; 73 struct timer_list timer; 74 const struct linedisp_ops *ops; 75 struct linedisp_map *map; 76 char *buf; 77 char *message; 78 unsigned int num_chars; 79 unsigned int message_len; 80 unsigned int scroll_pos; 81 unsigned int scroll_rate; 82 unsigned int id; 83 }; 84 85 int linedisp_attach(struct linedisp *linedisp, struct device *dev, 86 unsigned int num_chars, const struct linedisp_ops *ops); 87 void linedisp_detach(struct device *dev); 88 int linedisp_register(struct linedisp *linedisp, struct device *parent, 89 unsigned int num_chars, const struct linedisp_ops *ops); 90 void linedisp_unregister(struct linedisp *linedisp); 91 92 #endif /* LINEDISP_H */ 93