linux/drivers/auxdisplay/line-display.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Character line display core support
 *
 * Copyright (C) 2016 Imagination Technologies
 * Author: Paul Burton <[email protected]>
 *
 * Copyright (C) 2021 Glider bv
 */

#ifndef CONFIG_PANEL_BOOT_MESSAGE
#include <generated/utsrelease.h>
#endif

#include <linux/container_of.h>
#include <linux/device.h>
#include <linux/export.h>
#include <linux/idr.h>
#include <linux/jiffies.h>
#include <linux/kstrtox.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/sysfs.h>
#include <linux/timer.h>

#include <linux/map_to_7segment.h>
#include <linux/map_to_14segment.h>

#include "line-display.h"

#define DEFAULT_SCROLL_RATE …

/**
 * linedisp_scroll() - scroll the display by a character
 * @t: really a pointer to the private data structure
 *
 * Scroll the current message along the display by one character, rearming the
 * timer if required.
 */
static void linedisp_scroll(struct timer_list *t)
{ … }

/**
 * linedisp_display() - set the message to be displayed
 * @linedisp: pointer to the private data structure
 * @msg: the message to display
 * @count: length of msg, or -1
 *
 * Display a new message @msg on the display. @msg can be longer than the
 * number of characters the display can display, in which case it will begin
 * scrolling across the display.
 *
 * Return: 0 on success, -ENOMEM on memory allocation failure
 */
static int linedisp_display(struct linedisp *linedisp, const char *msg,
			    ssize_t count)
{ … }

/**
 * message_show() - read message via sysfs
 * @dev: the display device
 * @attr: the display message attribute
 * @buf: the buffer to read the message into
 *
 * Read the current message being displayed or scrolled across the display into
 * @buf, for reads from sysfs.
 *
 * Return: the number of characters written to @buf
 */
static ssize_t message_show(struct device *dev, struct device_attribute *attr,
			    char *buf)
{ … }

/**
 * message_store() - write a new message via sysfs
 * @dev: the display device
 * @attr: the display message attribute
 * @buf: the buffer containing the new message
 * @count: the size of the message in @buf
 *
 * Write a new message to display or scroll across the display from sysfs.
 *
 * Return: the size of the message on success, else -ERRNO
 */
static ssize_t message_store(struct device *dev, struct device_attribute *attr,
			     const char *buf, size_t count)
{ … }

static DEVICE_ATTR_RW(message);

static ssize_t scroll_step_ms_show(struct device *dev,
				   struct device_attribute *attr, char *buf)
{ … }

static ssize_t scroll_step_ms_store(struct device *dev,
				    struct device_attribute *attr,
				    const char *buf, size_t count)
{ … }

static DEVICE_ATTR_RW(scroll_step_ms);

static ssize_t map_seg_show(struct device *dev, struct device_attribute *attr, char *buf)
{ … }

static ssize_t map_seg_store(struct device *dev, struct device_attribute *attr,
			     const char *buf, size_t count)
{ … }

static const SEG7_DEFAULT_MAP(initial_map_seg7);
static DEVICE_ATTR(map_seg7, 0644, map_seg_show, map_seg_store);

static const SEG14_DEFAULT_MAP(initial_map_seg14);
static DEVICE_ATTR(map_seg14, 0644, map_seg_show, map_seg_store);

static struct attribute *linedisp_attrs[] = …;

static umode_t linedisp_attr_is_visible(struct kobject *kobj, struct attribute *attr, int n)
{
	struct device *dev = kobj_to_dev(kobj);
	struct linedisp *linedisp = container_of(dev, struct linedisp, dev);
	struct linedisp_map *map = linedisp->map;
	umode_t mode = attr->mode;

	if (attr == &dev_attr_map_seg7.attr) {
		if (!map)
			return 0;
		if (map->type != LINEDISP_MAP_SEG7)
			return 0;
	}

	if (attr == &dev_attr_map_seg14.attr) {
		if (!map)
			return 0;
		if (map->type != LINEDISP_MAP_SEG14)
			return 0;
	}

	return mode;
};

static const struct attribute_group linedisp_group = …;
__ATTRIBUTE_GROUPS(…);

static DEFINE_IDA(linedisp_id);

static void linedisp_release(struct device *dev)
{ … }

static const struct device_type linedisp_type = …;

static int linedisp_init_map(struct linedisp *linedisp)
{ … }

#ifdef CONFIG_PANEL_BOOT_MESSAGE
#define LINEDISP_INIT_TEXT …
#else
#define LINEDISP_INIT_TEXT …
#endif

/**
 * linedisp_register - register a character line display
 * @linedisp: pointer to character line display structure
 * @parent: parent device
 * @num_chars: the number of characters that can be displayed
 * @ops: character line display operations
 *
 * Return: zero on success, else a negative error code.
 */
int linedisp_register(struct linedisp *linedisp, struct device *parent,
		      unsigned int num_chars, const struct linedisp_ops *ops)
{ … }
EXPORT_SYMBOL_NS_GPL(…);

/**
 * linedisp_unregister - unregister a character line display
 * @linedisp: pointer to character line display structure registered previously
 *	      with linedisp_register()
 */
void linedisp_unregister(struct linedisp *linedisp)
{ … }
EXPORT_SYMBOL_NS_GPL(…);

MODULE_DESCRIPTION(…) …;
MODULE_LICENSE(…) …;