Author | Tokens | Token Proportion | Commits | Commit Proportion |
---|---|---|---|---|
Geert Uytterhoeven | 725 | 77.21% | 4 | 50.00% |
Paul Burton | 205 | 21.83% | 1 | 12.50% |
Jesse Chan | 7 | 0.75% | 1 | 12.50% |
Thomas Gleixner | 1 | 0.11% | 1 | 12.50% |
Kees Cook | 1 | 0.11% | 1 | 12.50% |
Total | 939 | 8 |
// SPDX-License-Identifier: GPL-2.0-or-later /* * Character line display core support * * Copyright (C) 2016 Imagination Technologies * Author: Paul Burton <paul.burton@mips.com> * * Copyright (C) 2021 Glider bv */ #include <generated/utsrelease.h> #include <linux/device.h> #include <linux/module.h> #include <linux/slab.h> #include <linux/string.h> #include <linux/sysfs.h> #include <linux/timer.h> #include "line-display.h" #define DEFAULT_SCROLL_RATE (HZ / 2) /** * 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) { struct linedisp *linedisp = from_timer(linedisp, t, timer); unsigned int i, ch = linedisp->scroll_pos; unsigned int num_chars = linedisp->num_chars; /* update the current message string */ for (i = 0; i < num_chars;) { /* copy as many characters from the string as possible */ for (; i < num_chars && ch < linedisp->message_len; i++, ch++) linedisp->buf[i] = linedisp->message[ch]; /* wrap around to the start of the string */ ch = 0; } /* update the display */ linedisp->update(linedisp); /* move on to the next character */ linedisp->scroll_pos++; linedisp->scroll_pos %= linedisp->message_len; /* rearm the timer */ if (linedisp->message_len > num_chars && linedisp->scroll_rate) mod_timer(&linedisp->timer, jiffies + linedisp->scroll_rate); } /** * 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) { char *new_msg; /* stop the scroll timer */ del_timer_sync(&linedisp->timer); if (count == -1) count = strlen(msg); /* if the string ends with a newline, trim it */ if (msg[count - 1] == '\n') count--; if (!count) { /* Clear the display */ kfree(linedisp->message); linedisp->message = NULL; linedisp->message_len = 0; memset(linedisp->buf, ' ', linedisp->num_chars); linedisp->update(linedisp); return 0; } new_msg = kmemdup_nul(msg, count, GFP_KERNEL); if (!new_msg) return -ENOMEM; kfree(linedisp->message); linedisp->message = new_msg; linedisp->message_len = count; linedisp->scroll_pos = 0; /* update the display */ linedisp_scroll(&linedisp->timer); return 0; } /** * 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) { struct linedisp *linedisp = container_of(dev, struct linedisp, dev); return sysfs_emit(buf, "%s\n", linedisp->message); } /** * 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) { struct linedisp *linedisp = container_of(dev, struct linedisp, dev); int err; err = linedisp_display(linedisp, buf, count); return err ?: count; } static DEVICE_ATTR_RW(message); static ssize_t scroll_step_ms_show(struct device *dev, struct device_attribute *attr, char *buf) { struct linedisp *linedisp = container_of(dev, struct linedisp, dev); return sysfs_emit(buf, "%u\n", jiffies_to_msecs(linedisp->scroll_rate)); } static ssize_t scroll_step_ms_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { struct linedisp *linedisp = container_of(dev, struct linedisp, dev); unsigned int ms; if (kstrtouint(buf, 10, &ms) != 0) return -EINVAL; linedisp->scroll_rate = msecs_to_jiffies(ms); if (linedisp->message && linedisp->message_len > linedisp->num_chars) { del_timer_sync(&linedisp->timer); if (linedisp->scroll_rate) linedisp_scroll(&linedisp->timer); } return count; } static DEVICE_ATTR_RW(scroll_step_ms); static struct attribute *linedisp_attrs[] = { &dev_attr_message.attr, &dev_attr_scroll_step_ms.attr, NULL, }; ATTRIBUTE_GROUPS(linedisp); static const struct device_type linedisp_type = { .groups = linedisp_groups, }; /** * 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 * @buf: pointer to a buffer that can hold @num_chars characters * @update: Function called to update the display. This must not sleep! * * Return: zero on success, else a negative error code. */ int linedisp_register(struct linedisp *linedisp, struct device *parent, unsigned int num_chars, char *buf, void (*update)(struct linedisp *linedisp)) { static atomic_t linedisp_id = ATOMIC_INIT(-1); int err; memset(linedisp, 0, sizeof(*linedisp)); linedisp->dev.parent = parent; linedisp->dev.type = &linedisp_type; linedisp->update = update; linedisp->buf = buf; linedisp->num_chars = num_chars; linedisp->scroll_rate = DEFAULT_SCROLL_RATE; device_initialize(&linedisp->dev); dev_set_name(&linedisp->dev, "linedisp.%lu", (unsigned long)atomic_inc_return(&linedisp_id)); /* initialise a timer for scrolling the message */ timer_setup(&linedisp->timer, linedisp_scroll, 0); err = device_add(&linedisp->dev); if (err) goto out_del_timer; /* display a default message */ err = linedisp_display(linedisp, "Linux " UTS_RELEASE " ", -1); if (err) goto out_del_dev; return 0; out_del_dev: device_del(&linedisp->dev); out_del_timer: del_timer_sync(&linedisp->timer); put_device(&linedisp->dev); return err; } EXPORT_SYMBOL_GPL(linedisp_register); /** * 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) { device_del(&linedisp->dev); del_timer_sync(&linedisp->timer); kfree(linedisp->message); put_device(&linedisp->dev); } EXPORT_SYMBOL_GPL(linedisp_unregister); MODULE_LICENSE("GPL");
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