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680 lines
15 KiB
680 lines
15 KiB
// SPDX-License-Identifier: GPL-2.0+ |
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/* |
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* Character LCD driver for Linux |
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* |
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* Copyright (C) 2000-2008, Willy Tarreau <[email protected]> |
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* Copyright (C) 2016-2017 Glider bvba |
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*/ |
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#include <linux/atomic.h> |
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#include <linux/ctype.h> |
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#include <linux/fs.h> |
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#include <linux/miscdevice.h> |
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#include <linux/module.h> |
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#include <linux/notifier.h> |
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#include <linux/reboot.h> |
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#include <linux/slab.h> |
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#include <linux/uaccess.h> |
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#include <linux/workqueue.h> |
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#include <generated/utsrelease.h> |
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#include "charlcd.h" |
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/* Keep the backlight on this many seconds for each flash */ |
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#define LCD_BL_TEMPO_PERIOD 4 |
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#define LCD_ESCAPE_LEN 24 /* Max chars for LCD escape command */ |
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#define LCD_ESCAPE_CHAR 27 /* Use char 27 for escape command */ |
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struct charlcd_priv { |
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struct charlcd lcd; |
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struct delayed_work bl_work; |
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struct mutex bl_tempo_lock; /* Protects access to bl_tempo */ |
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bool bl_tempo; |
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bool must_clear; |
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/* contains the LCD config state */ |
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unsigned long int flags; |
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/* Current escape sequence and it's length or -1 if outside */ |
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struct { |
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char buf[LCD_ESCAPE_LEN + 1]; |
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int len; |
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} esc_seq; |
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unsigned long long drvdata[]; |
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}; |
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#define charlcd_to_priv(p) container_of(p, struct charlcd_priv, lcd) |
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/* Device single-open policy control */ |
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static atomic_t charlcd_available = ATOMIC_INIT(1); |
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/* turn the backlight on or off */ |
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void charlcd_backlight(struct charlcd *lcd, enum charlcd_onoff on) |
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{ |
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struct charlcd_priv *priv = charlcd_to_priv(lcd); |
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if (!lcd->ops->backlight) |
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return; |
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mutex_lock(&priv->bl_tempo_lock); |
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if (!priv->bl_tempo) |
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lcd->ops->backlight(lcd, on); |
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mutex_unlock(&priv->bl_tempo_lock); |
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} |
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EXPORT_SYMBOL_GPL(charlcd_backlight); |
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static void charlcd_bl_off(struct work_struct *work) |
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{ |
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struct delayed_work *dwork = to_delayed_work(work); |
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struct charlcd_priv *priv = |
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container_of(dwork, struct charlcd_priv, bl_work); |
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mutex_lock(&priv->bl_tempo_lock); |
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if (priv->bl_tempo) { |
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priv->bl_tempo = false; |
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if (!(priv->flags & LCD_FLAG_L)) |
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priv->lcd.ops->backlight(&priv->lcd, CHARLCD_OFF); |
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} |
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mutex_unlock(&priv->bl_tempo_lock); |
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} |
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/* turn the backlight on for a little while */ |
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void charlcd_poke(struct charlcd *lcd) |
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{ |
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struct charlcd_priv *priv = charlcd_to_priv(lcd); |
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if (!lcd->ops->backlight) |
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return; |
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cancel_delayed_work_sync(&priv->bl_work); |
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mutex_lock(&priv->bl_tempo_lock); |
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if (!priv->bl_tempo && !(priv->flags & LCD_FLAG_L)) |
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lcd->ops->backlight(lcd, CHARLCD_ON); |
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priv->bl_tempo = true; |
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schedule_delayed_work(&priv->bl_work, LCD_BL_TEMPO_PERIOD * HZ); |
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mutex_unlock(&priv->bl_tempo_lock); |
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} |
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EXPORT_SYMBOL_GPL(charlcd_poke); |
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static void charlcd_home(struct charlcd *lcd) |
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{ |
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lcd->addr.x = 0; |
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lcd->addr.y = 0; |
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lcd->ops->home(lcd); |
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} |
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static void charlcd_print(struct charlcd *lcd, char c) |
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{ |
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if (lcd->addr.x >= lcd->width) |
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return; |
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if (lcd->char_conv) |
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c = lcd->char_conv[(unsigned char)c]; |
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if (!lcd->ops->print(lcd, c)) |
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lcd->addr.x++; |
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/* prevents the cursor from wrapping onto the next line */ |
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if (lcd->addr.x == lcd->width) |
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lcd->ops->gotoxy(lcd, lcd->addr.x - 1, lcd->addr.y); |
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} |
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static void charlcd_clear_display(struct charlcd *lcd) |
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{ |
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lcd->ops->clear_display(lcd); |
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lcd->addr.x = 0; |
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lcd->addr.y = 0; |
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} |
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/* |
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* Parses a movement command of the form "(.*);", where the group can be |
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* any number of subcommands of the form "(x|y)[0-9]+". |
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* |
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* Returns whether the command is valid. The position arguments are |
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* only written if the parsing was successful. |
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* |
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* For instance: |
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* - ";" returns (<original x>, <original y>). |
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* - "x1;" returns (1, <original y>). |
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* - "y2x1;" returns (1, 2). |
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* - "x12y34x56;" returns (56, 34). |
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* - "" fails. |
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* - "x" fails. |
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* - "x;" fails. |
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* - "x1" fails. |
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* - "xy12;" fails. |
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* - "x12yy12;" fails. |
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* - "xx" fails. |
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*/ |
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static bool parse_xy(const char *s, unsigned long *x, unsigned long *y) |
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{ |
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unsigned long new_x = *x; |
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unsigned long new_y = *y; |
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char *p; |
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for (;;) { |
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if (!*s) |
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return false; |
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if (*s == ';') |
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break; |
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if (*s == 'x') { |
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new_x = simple_strtoul(s + 1, &p, 10); |
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if (p == s + 1) |
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return false; |
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s = p; |
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} else if (*s == 'y') { |
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new_y = simple_strtoul(s + 1, &p, 10); |
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if (p == s + 1) |
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return false; |
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s = p; |
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} else { |
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return false; |
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} |
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} |
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*x = new_x; |
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*y = new_y; |
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return true; |
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} |
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/* |
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* These are the file operation function for user access to /dev/lcd |
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* This function can also be called from inside the kernel, by |
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* setting file and ppos to NULL. |
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* |
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*/ |
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static inline int handle_lcd_special_code(struct charlcd *lcd) |
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{ |
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struct charlcd_priv *priv = charlcd_to_priv(lcd); |
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/* LCD special codes */ |
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int processed = 0; |
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char *esc = priv->esc_seq.buf + 2; |
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int oldflags = priv->flags; |
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/* check for display mode flags */ |
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switch (*esc) { |
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case 'D': /* Display ON */ |
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priv->flags |= LCD_FLAG_D; |
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if (priv->flags != oldflags) |
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lcd->ops->display(lcd, CHARLCD_ON); |
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processed = 1; |
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break; |
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case 'd': /* Display OFF */ |
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priv->flags &= ~LCD_FLAG_D; |
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if (priv->flags != oldflags) |
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lcd->ops->display(lcd, CHARLCD_OFF); |
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processed = 1; |
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break; |
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case 'C': /* Cursor ON */ |
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priv->flags |= LCD_FLAG_C; |
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if (priv->flags != oldflags) |
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lcd->ops->cursor(lcd, CHARLCD_ON); |
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processed = 1; |
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break; |
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case 'c': /* Cursor OFF */ |
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priv->flags &= ~LCD_FLAG_C; |
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if (priv->flags != oldflags) |
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lcd->ops->cursor(lcd, CHARLCD_OFF); |
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processed = 1; |
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break; |
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case 'B': /* Blink ON */ |
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priv->flags |= LCD_FLAG_B; |
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if (priv->flags != oldflags) |
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lcd->ops->blink(lcd, CHARLCD_ON); |
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processed = 1; |
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break; |
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case 'b': /* Blink OFF */ |
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priv->flags &= ~LCD_FLAG_B; |
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if (priv->flags != oldflags) |
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lcd->ops->blink(lcd, CHARLCD_OFF); |
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processed = 1; |
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break; |
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case '+': /* Back light ON */ |
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priv->flags |= LCD_FLAG_L; |
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if (priv->flags != oldflags) |
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charlcd_backlight(lcd, CHARLCD_ON); |
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processed = 1; |
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break; |
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case '-': /* Back light OFF */ |
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priv->flags &= ~LCD_FLAG_L; |
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if (priv->flags != oldflags) |
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charlcd_backlight(lcd, CHARLCD_OFF); |
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processed = 1; |
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break; |
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case '*': /* Flash back light */ |
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charlcd_poke(lcd); |
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processed = 1; |
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break; |
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case 'f': /* Small Font */ |
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priv->flags &= ~LCD_FLAG_F; |
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if (priv->flags != oldflags) |
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lcd->ops->fontsize(lcd, CHARLCD_FONTSIZE_SMALL); |
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processed = 1; |
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break; |
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case 'F': /* Large Font */ |
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priv->flags |= LCD_FLAG_F; |
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if (priv->flags != oldflags) |
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lcd->ops->fontsize(lcd, CHARLCD_FONTSIZE_LARGE); |
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processed = 1; |
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break; |
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case 'n': /* One Line */ |
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priv->flags &= ~LCD_FLAG_N; |
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if (priv->flags != oldflags) |
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lcd->ops->lines(lcd, CHARLCD_LINES_1); |
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processed = 1; |
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break; |
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case 'N': /* Two Lines */ |
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priv->flags |= LCD_FLAG_N; |
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if (priv->flags != oldflags) |
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lcd->ops->lines(lcd, CHARLCD_LINES_2); |
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processed = 1; |
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break; |
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case 'l': /* Shift Cursor Left */ |
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if (lcd->addr.x > 0) { |
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if (!lcd->ops->shift_cursor(lcd, CHARLCD_SHIFT_LEFT)) |
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lcd->addr.x--; |
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} |
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processed = 1; |
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break; |
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case 'r': /* shift cursor right */ |
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if (lcd->addr.x < lcd->width) { |
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if (!lcd->ops->shift_cursor(lcd, CHARLCD_SHIFT_RIGHT)) |
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lcd->addr.x++; |
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} |
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processed = 1; |
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break; |
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case 'L': /* shift display left */ |
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lcd->ops->shift_display(lcd, CHARLCD_SHIFT_LEFT); |
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processed = 1; |
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break; |
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case 'R': /* shift display right */ |
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lcd->ops->shift_display(lcd, CHARLCD_SHIFT_RIGHT); |
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processed = 1; |
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break; |
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case 'k': { /* kill end of line */ |
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int x, xs, ys; |
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xs = lcd->addr.x; |
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ys = lcd->addr.y; |
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for (x = lcd->addr.x; x < lcd->width; x++) |
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lcd->ops->print(lcd, ' '); |
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/* restore cursor position */ |
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lcd->addr.x = xs; |
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lcd->addr.y = ys; |
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lcd->ops->gotoxy(lcd, lcd->addr.x, lcd->addr.y); |
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processed = 1; |
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break; |
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} |
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case 'I': /* reinitialize display */ |
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lcd->ops->init_display(lcd); |
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priv->flags = ((lcd->height > 1) ? LCD_FLAG_N : 0) | LCD_FLAG_D | |
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LCD_FLAG_C | LCD_FLAG_B; |
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processed = 1; |
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break; |
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case 'G': |
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if (lcd->ops->redefine_char) |
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processed = lcd->ops->redefine_char(lcd, esc); |
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else |
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processed = 1; |
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break; |
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case 'x': /* gotoxy : LxXXX[yYYY]; */ |
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case 'y': /* gotoxy : LyYYY[xXXX]; */ |
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if (priv->esc_seq.buf[priv->esc_seq.len - 1] != ';') |
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break; |
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/* If the command is valid, move to the new address */ |
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if (parse_xy(esc, &lcd->addr.x, &lcd->addr.y)) |
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lcd->ops->gotoxy(lcd, lcd->addr.x, lcd->addr.y); |
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/* Regardless of its validity, mark as processed */ |
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processed = 1; |
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break; |
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} |
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return processed; |
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} |
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static void charlcd_write_char(struct charlcd *lcd, char c) |
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{ |
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struct charlcd_priv *priv = charlcd_to_priv(lcd); |
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/* first, we'll test if we're in escape mode */ |
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if ((c != '\n') && priv->esc_seq.len >= 0) { |
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/* yes, let's add this char to the buffer */ |
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priv->esc_seq.buf[priv->esc_seq.len++] = c; |
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priv->esc_seq.buf[priv->esc_seq.len] = '\0'; |
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} else { |
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/* aborts any previous escape sequence */ |
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priv->esc_seq.len = -1; |
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switch (c) { |
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case LCD_ESCAPE_CHAR: |
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/* start of an escape sequence */ |
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priv->esc_seq.len = 0; |
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priv->esc_seq.buf[priv->esc_seq.len] = '\0'; |
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break; |
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case '\b': |
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/* go back one char and clear it */ |
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if (lcd->addr.x > 0) { |
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/* back one char */ |
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if (!lcd->ops->shift_cursor(lcd, |
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CHARLCD_SHIFT_LEFT)) |
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lcd->addr.x--; |
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} |
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/* replace with a space */ |
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charlcd_print(lcd, ' '); |
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/* back one char again */ |
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if (!lcd->ops->shift_cursor(lcd, CHARLCD_SHIFT_LEFT)) |
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lcd->addr.x--; |
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break; |
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case '\f': |
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/* quickly clear the display */ |
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charlcd_clear_display(lcd); |
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break; |
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case '\n': |
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/* |
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* flush the remainder of the current line and |
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* go to the beginning of the next line |
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*/ |
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for (; lcd->addr.x < lcd->width; lcd->addr.x++) |
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lcd->ops->print(lcd, ' '); |
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lcd->addr.x = 0; |
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lcd->addr.y = (lcd->addr.y + 1) % lcd->height; |
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lcd->ops->gotoxy(lcd, lcd->addr.x, lcd->addr.y); |
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break; |
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case '\r': |
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/* go to the beginning of the same line */ |
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lcd->addr.x = 0; |
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lcd->ops->gotoxy(lcd, lcd->addr.x, lcd->addr.y); |
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break; |
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case '\t': |
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/* print a space instead of the tab */ |
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charlcd_print(lcd, ' '); |
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break; |
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default: |
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/* simply print this char */ |
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charlcd_print(lcd, c); |
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break; |
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} |
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} |
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/* |
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* now we'll see if we're in an escape mode and if the current |
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* escape sequence can be understood. |
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*/ |
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if (priv->esc_seq.len >= 2) { |
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int processed = 0; |
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if (!strcmp(priv->esc_seq.buf, "[2J")) { |
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/* clear the display */ |
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charlcd_clear_display(lcd); |
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processed = 1; |
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} else if (!strcmp(priv->esc_seq.buf, "[H")) { |
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/* cursor to home */ |
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charlcd_home(lcd); |
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processed = 1; |
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} |
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/* codes starting with ^[[L */ |
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else if ((priv->esc_seq.len >= 3) && |
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(priv->esc_seq.buf[0] == '[') && |
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(priv->esc_seq.buf[1] == 'L')) { |
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processed = handle_lcd_special_code(lcd); |
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} |
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/* LCD special escape codes */ |
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/* |
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* flush the escape sequence if it's been processed |
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* or if it is getting too long. |
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*/ |
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if (processed || (priv->esc_seq.len >= LCD_ESCAPE_LEN)) |
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priv->esc_seq.len = -1; |
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} /* escape codes */ |
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} |
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static struct charlcd *the_charlcd; |
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static ssize_t charlcd_write(struct file *file, const char __user *buf, |
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size_t count, loff_t *ppos) |
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{ |
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const char __user *tmp = buf; |
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char c; |
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for (; count-- > 0; (*ppos)++, tmp++) { |
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if (((count + 1) & 0x1f) == 0) { |
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/* |
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* charlcd_write() is invoked as a VFS->write() callback |
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* and as such it is always invoked from preemptible |
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* context and may sleep. |
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*/ |
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cond_resched(); |
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} |
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if (get_user(c, tmp)) |
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return -EFAULT; |
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charlcd_write_char(the_charlcd, c); |
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} |
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return tmp - buf; |
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} |
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static int charlcd_open(struct inode *inode, struct file *file) |
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{ |
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struct charlcd_priv *priv = charlcd_to_priv(the_charlcd); |
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int ret; |
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ret = -EBUSY; |
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if (!atomic_dec_and_test(&charlcd_available)) |
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goto fail; /* open only once at a time */ |
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ret = -EPERM; |
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if (file->f_mode & FMODE_READ) /* device is write-only */ |
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goto fail; |
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if (priv->must_clear) { |
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priv->lcd.ops->clear_display(&priv->lcd); |
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priv->must_clear = false; |
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priv->lcd.addr.x = 0; |
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priv->lcd.addr.y = 0; |
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} |
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return nonseekable_open(inode, file); |
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fail: |
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atomic_inc(&charlcd_available); |
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return ret; |
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} |
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static int charlcd_release(struct inode *inode, struct file *file) |
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{ |
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atomic_inc(&charlcd_available); |
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return 0; |
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} |
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static const struct file_operations charlcd_fops = { |
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.write = charlcd_write, |
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.open = charlcd_open, |
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.release = charlcd_release, |
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.llseek = no_llseek, |
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}; |
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static struct miscdevice charlcd_dev = { |
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.minor = LCD_MINOR, |
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.name = "lcd", |
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.fops = &charlcd_fops, |
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}; |
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static void charlcd_puts(struct charlcd *lcd, const char *s) |
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{ |
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const char *tmp = s; |
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int count = strlen(s); |
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for (; count-- > 0; tmp++) { |
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if (((count + 1) & 0x1f) == 0) |
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cond_resched(); |
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charlcd_write_char(lcd, *tmp); |
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} |
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} |
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#ifdef CONFIG_PANEL_BOOT_MESSAGE |
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#define LCD_INIT_TEXT CONFIG_PANEL_BOOT_MESSAGE |
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#else |
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#define LCD_INIT_TEXT "Linux-" UTS_RELEASE "\n" |
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#endif |
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#ifdef CONFIG_CHARLCD_BL_ON |
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#define LCD_INIT_BL "\x1b[L+" |
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#elif defined(CONFIG_CHARLCD_BL_FLASH) |
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#define LCD_INIT_BL "\x1b[L*" |
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#else |
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#define LCD_INIT_BL "\x1b[L-" |
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#endif |
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/* initialize the LCD driver */ |
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static int charlcd_init(struct charlcd *lcd) |
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{ |
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struct charlcd_priv *priv = charlcd_to_priv(lcd); |
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int ret; |
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priv->flags = ((lcd->height > 1) ? LCD_FLAG_N : 0) | LCD_FLAG_D | |
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LCD_FLAG_C | LCD_FLAG_B; |
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if (lcd->ops->backlight) { |
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mutex_init(&priv->bl_tempo_lock); |
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INIT_DELAYED_WORK(&priv->bl_work, charlcd_bl_off); |
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} |
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|
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/* |
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* before this line, we must NOT send anything to the display. |
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* Since charlcd_init_display() needs to write data, we have to |
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* enable mark the LCD initialized just before. |
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*/ |
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ret = lcd->ops->init_display(lcd); |
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if (ret) |
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return ret; |
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|
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/* display a short message */ |
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charlcd_puts(lcd, "\x1b[Lc\x1b[Lb" LCD_INIT_BL LCD_INIT_TEXT); |
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|
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/* clear the display on the next device opening */ |
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priv->must_clear = true; |
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charlcd_home(lcd); |
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return 0; |
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} |
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struct charlcd *charlcd_alloc(void) |
|
{ |
|
struct charlcd_priv *priv; |
|
struct charlcd *lcd; |
|
|
|
priv = kzalloc(sizeof(*priv), GFP_KERNEL); |
|
if (!priv) |
|
return NULL; |
|
|
|
priv->esc_seq.len = -1; |
|
|
|
lcd = &priv->lcd; |
|
|
|
return lcd; |
|
} |
|
EXPORT_SYMBOL_GPL(charlcd_alloc); |
|
|
|
void charlcd_free(struct charlcd *lcd) |
|
{ |
|
kfree(charlcd_to_priv(lcd)); |
|
} |
|
EXPORT_SYMBOL_GPL(charlcd_free); |
|
|
|
static int panel_notify_sys(struct notifier_block *this, unsigned long code, |
|
void *unused) |
|
{ |
|
struct charlcd *lcd = the_charlcd; |
|
|
|
switch (code) { |
|
case SYS_DOWN: |
|
charlcd_puts(lcd, |
|
"\x0cReloading\nSystem...\x1b[Lc\x1b[Lb\x1b[L+"); |
|
break; |
|
case SYS_HALT: |
|
charlcd_puts(lcd, "\x0cSystem Halted.\x1b[Lc\x1b[Lb\x1b[L+"); |
|
break; |
|
case SYS_POWER_OFF: |
|
charlcd_puts(lcd, "\x0cPower off.\x1b[Lc\x1b[Lb\x1b[L+"); |
|
break; |
|
default: |
|
break; |
|
} |
|
return NOTIFY_DONE; |
|
} |
|
|
|
static struct notifier_block panel_notifier = { |
|
panel_notify_sys, |
|
NULL, |
|
0 |
|
}; |
|
|
|
int charlcd_register(struct charlcd *lcd) |
|
{ |
|
int ret; |
|
|
|
ret = charlcd_init(lcd); |
|
if (ret) |
|
return ret; |
|
|
|
ret = misc_register(&charlcd_dev); |
|
if (ret) |
|
return ret; |
|
|
|
the_charlcd = lcd; |
|
register_reboot_notifier(&panel_notifier); |
|
return 0; |
|
} |
|
EXPORT_SYMBOL_GPL(charlcd_register); |
|
|
|
int charlcd_unregister(struct charlcd *lcd) |
|
{ |
|
struct charlcd_priv *priv = charlcd_to_priv(lcd); |
|
|
|
unregister_reboot_notifier(&panel_notifier); |
|
charlcd_puts(lcd, "\x0cLCD driver unloaded.\x1b[Lc\x1b[Lb\x1b[L-"); |
|
misc_deregister(&charlcd_dev); |
|
the_charlcd = NULL; |
|
if (lcd->ops->backlight) { |
|
cancel_delayed_work_sync(&priv->bl_work); |
|
priv->lcd.ops->backlight(&priv->lcd, CHARLCD_OFF); |
|
} |
|
|
|
return 0; |
|
} |
|
EXPORT_SYMBOL_GPL(charlcd_unregister); |
|
|
|
MODULE_LICENSE("GPL");
|
|
|