1 // SPDX-License-Identifier: GPL-2.0+
3  * Character LCD driver for Linux
5  * Copyright (C) 2000-2008, Willy Tarreau <w@1wt.eu>
6  * Copyright (C) 2016-2017 Glider bvba
24 /* Keep the backlight on this many seconds for each flash */
27 #define LCD_ESCAPE_LEN		24	/* Max chars for LCD escape command */
31 	struct charlcd lcd;  member
39 	/* contains the LCD config state */
42 	/* Current escape sequence and it's length or -1 if outside */
51 #define charlcd_to_priv(p)	container_of(p, struct charlcd_priv, lcd)
53 /* Device single-open policy control */
56 /* turn the backlight on or off */
57 void charlcd_backlight(struct charlcd *lcd, enum charlcd_onoff on)  in charlcd_backlight()  argument
59 	struct charlcd_priv *priv = charlcd_to_priv(lcd);  in charlcd_backlight()
61 	if (!lcd->ops->backlight)  in charlcd_backlight()
64 	mutex_lock(&priv->bl_tempo_lock);  in charlcd_backlight()
65 	if (!priv->bl_tempo)  in charlcd_backlight()
66 		lcd->ops->backlight(lcd, on);  in charlcd_backlight()
67 	mutex_unlock(&priv->bl_tempo_lock);  in charlcd_backlight()
77 	mutex_lock(&priv->bl_tempo_lock);  in charlcd_bl_off()
78 	if (priv->bl_tempo) {  in charlcd_bl_off()
79 		priv->bl_tempo = false;  in charlcd_bl_off()
80 		if (!(priv->flags & LCD_FLAG_L))  in charlcd_bl_off()
81 			priv->lcd.ops->backlight(&priv->lcd, CHARLCD_OFF);  in charlcd_bl_off()
83 	mutex_unlock(&priv->bl_tempo_lock);  in charlcd_bl_off()
86 /* turn the backlight on for a little while */
87 void charlcd_poke(struct charlcd *lcd)  in charlcd_poke()  argument
89 	struct charlcd_priv *priv = charlcd_to_priv(lcd);  in charlcd_poke()
91 	if (!lcd->ops->backlight)  in charlcd_poke()
94 	cancel_delayed_work_sync(&priv->bl_work);  in charlcd_poke()
96 	mutex_lock(&priv->bl_tempo_lock);  in charlcd_poke()
97 	if (!priv->bl_tempo && !(priv->flags & LCD_FLAG_L))  in charlcd_poke()
98 		lcd->ops->backlight(lcd, CHARLCD_ON);  in charlcd_poke()
99 	priv->bl_tempo = true;  in charlcd_poke()
100 	schedule_delayed_work(&priv->bl_work, LCD_BL_TEMPO_PERIOD * HZ);  in charlcd_poke()
101 	mutex_unlock(&priv->bl_tempo_lock);  in charlcd_poke()
105 static void charlcd_home(struct charlcd *lcd)  in charlcd_home()  argument
107 	lcd->addr.x = 0;  in charlcd_home()
108 	lcd->addr.y = 0;  in charlcd_home()
109 	lcd->ops->home(lcd);  in charlcd_home()
112 static void charlcd_print(struct charlcd *lcd, char c)  in charlcd_print()  argument
114 	if (lcd->addr.x >= lcd->width)  in charlcd_print()
117 	if (lcd->char_conv)  in charlcd_print()
118 		c = lcd->char_conv[(unsigned char)c];  in charlcd_print()
120 	if (!lcd->ops->print(lcd, c))  in charlcd_print()
121 		lcd->addr.x++;  in charlcd_print()
124 	if (lcd->addr.x == lcd->width)  in charlcd_print()
125 		lcd->ops->gotoxy(lcd, lcd->addr.x - 1, lcd->addr.y);  in charlcd_print()
128 static void charlcd_clear_display(struct charlcd *lcd)  in charlcd_clear_display()  argument
130 	lcd->ops->clear_display(lcd);  in charlcd_clear_display()
131 	lcd->addr.x = 0;  in charlcd_clear_display()
132 	lcd->addr.y = 0;  in charlcd_clear_display()
137  * any number of subcommands of the form "(x|y)[0-9]+".
143  *   - ";"          returns (<original x>, <original y>).
144  *   - "x1;"        returns (1, <original y>).
145  *   - "y2x1;"      returns (1, 2).
146  *   - "x12y34x56;" returns (56, 34).
147  *   - ""           fails.
148  *   - "x"          fails.
149  *   - "x;"         fails.
150  *   - "x1"         fails.
151  *   - "xy12;"      fails.
152  *   - "x12yy12;"   fails.
153  *   - "xx"         fails.
189  * These are the file operation function for user access to /dev/lcd
195 static inline int handle_lcd_special_code(struct charlcd *lcd)  in handle_lcd_special_code()  argument
197 	struct charlcd_priv *priv = charlcd_to_priv(lcd);  in handle_lcd_special_code()
199 	/* LCD special codes */  in handle_lcd_special_code()
203 	char *esc = priv->esc_seq.buf + 2;  in handle_lcd_special_code()
204 	int oldflags = priv->flags;  in handle_lcd_special_code()
209 		priv->flags |= LCD_FLAG_D;  in handle_lcd_special_code()
210 		if (priv->flags != oldflags)  in handle_lcd_special_code()
211 			lcd->ops->display(lcd, CHARLCD_ON);  in handle_lcd_special_code()
216 		priv->flags &= ~LCD_FLAG_D;  in handle_lcd_special_code()
217 		if (priv->flags != oldflags)  in handle_lcd_special_code()
218 			lcd->ops->display(lcd, CHARLCD_OFF);  in handle_lcd_special_code()
223 		priv->flags |= LCD_FLAG_C;  in handle_lcd_special_code()
224 		if (priv->flags != oldflags)  in handle_lcd_special_code()
225 			lcd->ops->cursor(lcd, CHARLCD_ON);  in handle_lcd_special_code()
230 		priv->flags &= ~LCD_FLAG_C;  in handle_lcd_special_code()
231 		if (priv->flags != oldflags)  in handle_lcd_special_code()
232 			lcd->ops->cursor(lcd, CHARLCD_OFF);  in handle_lcd_special_code()
237 		priv->flags |= LCD_FLAG_B;  in handle_lcd_special_code()
238 		if (priv->flags != oldflags)  in handle_lcd_special_code()
239 			lcd->ops->blink(lcd, CHARLCD_ON);  in handle_lcd_special_code()
244 		priv->flags &= ~LCD_FLAG_B;  in handle_lcd_special_code()
245 		if (priv->flags != oldflags)  in handle_lcd_special_code()
246 			lcd->ops->blink(lcd, CHARLCD_OFF);  in handle_lcd_special_code()
251 		priv->flags |= LCD_FLAG_L;  in handle_lcd_special_code()
252 		if (priv->flags != oldflags)  in handle_lcd_special_code()
253 			charlcd_backlight(lcd, CHARLCD_ON);  in handle_lcd_special_code()
257 	case '-':	/* Back light OFF */  in handle_lcd_special_code()
258 		priv->flags &= ~LCD_FLAG_L;  in handle_lcd_special_code()
259 		if (priv->flags != oldflags)  in handle_lcd_special_code()
260 			charlcd_backlight(lcd, CHARLCD_OFF);  in handle_lcd_special_code()
265 		charlcd_poke(lcd);  in handle_lcd_special_code()
269 		priv->flags &= ~LCD_FLAG_F;  in handle_lcd_special_code()
270 		if (priv->flags != oldflags)  in handle_lcd_special_code()
271 			lcd->ops->fontsize(lcd, CHARLCD_FONTSIZE_SMALL);  in handle_lcd_special_code()
276 		priv->flags |= LCD_FLAG_F;  in handle_lcd_special_code()
277 		if (priv->flags != oldflags)  in handle_lcd_special_code()
278 			lcd->ops->fontsize(lcd, CHARLCD_FONTSIZE_LARGE);  in handle_lcd_special_code()
283 		priv->flags &= ~LCD_FLAG_N;  in handle_lcd_special_code()
284 		if (priv->flags != oldflags)  in handle_lcd_special_code()
285 			lcd->ops->lines(lcd, CHARLCD_LINES_1);  in handle_lcd_special_code()
290 		priv->flags |= LCD_FLAG_N;  in handle_lcd_special_code()
291 		if (priv->flags != oldflags)  in handle_lcd_special_code()
292 			lcd->ops->lines(lcd, CHARLCD_LINES_2);  in handle_lcd_special_code()
297 		if (lcd->addr.x > 0) {  in handle_lcd_special_code()
298 			if (!lcd->ops->shift_cursor(lcd, CHARLCD_SHIFT_LEFT))  in handle_lcd_special_code()
299 				lcd->addr.x--;  in handle_lcd_special_code()
305 		if (lcd->addr.x < lcd->width) {  in handle_lcd_special_code()
306 			if (!lcd->ops->shift_cursor(lcd, CHARLCD_SHIFT_RIGHT))  in handle_lcd_special_code()
307 				lcd->addr.x++;  in handle_lcd_special_code()
313 		lcd->ops->shift_display(lcd, CHARLCD_SHIFT_LEFT);  in handle_lcd_special_code()
317 		lcd->ops->shift_display(lcd, CHARLCD_SHIFT_RIGHT);  in handle_lcd_special_code()
323 		xs = lcd->addr.x;  in handle_lcd_special_code()
324 		ys = lcd->addr.y;  in handle_lcd_special_code()
325 		for (x = lcd->addr.x; x < lcd->width; x++)  in handle_lcd_special_code()
326 			lcd->ops->print(lcd, ' ');  in handle_lcd_special_code()
329 		lcd->addr.x = xs;  in handle_lcd_special_code()
330 		lcd->addr.y = ys;  in handle_lcd_special_code()
331 		lcd->ops->gotoxy(lcd, lcd->addr.x, lcd->addr.y);  in handle_lcd_special_code()
336 		lcd->ops->init_display(lcd);  in handle_lcd_special_code()
337 		priv->flags = ((lcd->height > 1) ? LCD_FLAG_N : 0) | LCD_FLAG_D |  in handle_lcd_special_code()
342 		if (lcd->ops->redefine_char)  in handle_lcd_special_code()
343 			processed = lcd->ops->redefine_char(lcd, esc);  in handle_lcd_special_code()
350 		if (priv->esc_seq.buf[priv->esc_seq.len - 1] != ';')  in handle_lcd_special_code()
354 		if (parse_xy(esc, &lcd->addr.x, &lcd->addr.y))  in handle_lcd_special_code()
355 			lcd->ops->gotoxy(lcd, lcd->addr.x, lcd->addr.y);  in handle_lcd_special_code()
365 static void charlcd_write_char(struct charlcd *lcd, char c)  in charlcd_write_char()  argument
367 	struct charlcd_priv *priv = charlcd_to_priv(lcd);  in charlcd_write_char()
370 	if ((c != '\n') && priv->esc_seq.len >= 0) {  in charlcd_write_char()
372 		priv->esc_seq.buf[priv->esc_seq.len++] = c;  in charlcd_write_char()
373 		priv->esc_seq.buf[priv->esc_seq.len] = '\0';  in charlcd_write_char()
376 		priv->esc_seq.len = -1;  in charlcd_write_char()
381 			priv->esc_seq.len = 0;  in charlcd_write_char()
382 			priv->esc_seq.buf[priv->esc_seq.len] = '\0';  in charlcd_write_char()
386 			if (lcd->addr.x > 0) {  in charlcd_write_char()
388 				if (!lcd->ops->shift_cursor(lcd,  in charlcd_write_char()
390 					lcd->addr.x--;  in charlcd_write_char()
393 			charlcd_print(lcd, ' ');  in charlcd_write_char()
395 			if (!lcd->ops->shift_cursor(lcd, CHARLCD_SHIFT_LEFT))  in charlcd_write_char()
396 				lcd->addr.x--;  in charlcd_write_char()
401 			charlcd_clear_display(lcd);  in charlcd_write_char()
408 			for (; lcd->addr.x < lcd->width; lcd->addr.x++)  in charlcd_write_char()
409 				lcd->ops->print(lcd, ' ');  in charlcd_write_char()
411 			lcd->addr.x = 0;  in charlcd_write_char()
412 			lcd->addr.y = (lcd->addr.y + 1) % lcd->height;  in charlcd_write_char()
413 			lcd->ops->gotoxy(lcd, lcd->addr.x, lcd->addr.y);  in charlcd_write_char()
417 			lcd->addr.x = 0;  in charlcd_write_char()
418 			lcd->ops->gotoxy(lcd, lcd->addr.x, lcd->addr.y);  in charlcd_write_char()
422 			charlcd_print(lcd, ' ');  in charlcd_write_char()
426 			charlcd_print(lcd, c);  in charlcd_write_char()
435 	if (priv->esc_seq.len >= 2) {  in charlcd_write_char()
438 		if (!strcmp(priv->esc_seq.buf, "[2J")) {  in charlcd_write_char()
440 			charlcd_clear_display(lcd);  in charlcd_write_char()
442 		} else if (!strcmp(priv->esc_seq.buf, "[H")) {  in charlcd_write_char()
444 			charlcd_home(lcd);  in charlcd_write_char()
448 		else if ((priv->esc_seq.len >= 3) &&  in charlcd_write_char()
449 			 (priv->esc_seq.buf[0] == '[') &&  in charlcd_write_char()
450 			 (priv->esc_seq.buf[1] == 'L')) {  in charlcd_write_char()
451 			processed = handle_lcd_special_code(lcd);  in charlcd_write_char()
454 		/* LCD special escape codes */  in charlcd_write_char()
459 		if (processed || (priv->esc_seq.len >= LCD_ESCAPE_LEN))  in charlcd_write_char()
460 			priv->esc_seq.len = -1;  in charlcd_write_char()
472 	for (; count-- > 0; (*ppos)++, tmp++) {  in charlcd_write()
475 			 * charlcd_write() is invoked as a VFS->write() callback  in charlcd_write()
483 			return -EFAULT;  in charlcd_write()
488 	return tmp - buf;  in charlcd_write()
496 	ret = -EBUSY;  in charlcd_open()
500 	ret = -EPERM;  in charlcd_open()
501 	if (file->f_mode & FMODE_READ)	/* device is write-only */  in charlcd_open()
504 	if (priv->must_clear) {  in charlcd_open()
505 		priv->lcd.ops->clear_display(&priv->lcd);  in charlcd_open()
506 		priv->must_clear = false;  in charlcd_open()
507 		priv->lcd.addr.x = 0;  in charlcd_open()
508 		priv->lcd.addr.y = 0;  in charlcd_open()
532 	.name	= "lcd",
536 static void charlcd_puts(struct charlcd *lcd, const char *s)  in charlcd_puts()  argument
541 	for (; count-- > 0; tmp++) {  in charlcd_puts()
545 		charlcd_write_char(lcd, *tmp);  in charlcd_puts()
552 #define LCD_INIT_TEXT "Linux-" UTS_RELEASE "\n"
560 #define LCD_INIT_BL "\x1b[L-"
563 /* initialize the LCD driver */
564 static int charlcd_init(struct charlcd *lcd)  in charlcd_init()  argument
566 	struct charlcd_priv *priv = charlcd_to_priv(lcd);  in charlcd_init()
569 	priv->flags = ((lcd->height > 1) ? LCD_FLAG_N : 0) | LCD_FLAG_D |  in charlcd_init()
571 	if (lcd->ops->backlight) {  in charlcd_init()
572 		mutex_init(&priv->bl_tempo_lock);  in charlcd_init()
573 		INIT_DELAYED_WORK(&priv->bl_work, charlcd_bl_off);  in charlcd_init()
579 	 * enable mark the LCD initialized just before.  in charlcd_init()
581 	ret = lcd->ops->init_display(lcd);  in charlcd_init()
586 	charlcd_puts(lcd, "\x1b[Lc\x1b[Lb" LCD_INIT_BL LCD_INIT_TEXT);  in charlcd_init()
589 	priv->must_clear = true;  in charlcd_init()
590 	charlcd_home(lcd);  in charlcd_init()
597 	struct charlcd *lcd;  in charlcd_alloc()  local
603 	priv->esc_seq.len = -1;  in charlcd_alloc()
605 	lcd = &priv->lcd;  in charlcd_alloc()
607 	return lcd;  in charlcd_alloc()
611 void charlcd_free(struct charlcd *lcd)  in charlcd_free()  argument
613 	kfree(charlcd_to_priv(lcd));  in charlcd_free()
620 	struct charlcd *lcd = the_charlcd;  in panel_notify_sys()  local
624 		charlcd_puts(lcd,  in panel_notify_sys()
628 		charlcd_puts(lcd, "\x0cSystem Halted.\x1b[Lc\x1b[Lb\x1b[L+");  in panel_notify_sys()
631 		charlcd_puts(lcd, "\x0cPower off.\x1b[Lc\x1b[Lb\x1b[L+");  in panel_notify_sys()
643 int charlcd_register(struct charlcd *lcd)  in charlcd_register()  argument
647 	ret = charlcd_init(lcd);  in charlcd_register()
655 	the_charlcd = lcd;  in charlcd_register()
661 int charlcd_unregister(struct charlcd *lcd)  in charlcd_unregister()  argument
663 	struct charlcd_priv *priv = charlcd_to_priv(lcd);  in charlcd_unregister()
666 	charlcd_puts(lcd, "\x0cLCD driver unloaded.\x1b[Lc\x1b[Lb\x1b[L-");  in charlcd_unregister()
669 	if (lcd->ops->backlight) {  in charlcd_unregister()
670 		cancel_delayed_work_sync(&priv->bl_work);  in charlcd_unregister()
671 		priv->lcd.ops->backlight(&priv->lcd, CHARLCD_OFF);  in charlcd_unregister()