drivers/auxdisplay/line-display.h

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