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Linux 4.16.11
[linux/fpc-iii.git] / drivers / auxdisplay / charlcd.c
blob642afd88870ba99ef1c79db74b457515079684b7
1 /*
2 * Character LCD driver for Linux
3 *
4 * Copyright (C) 2000-2008, Willy Tarreau <w@1wt.eu>
5 * Copyright (C) 2016-2017 Glider bvba
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 */
12
13 #include <linux/atomic.h>
14 #include <linux/delay.h>
15 #include <linux/fs.h>
16 #include <linux/miscdevice.h>
17 #include <linux/module.h>
18 #include <linux/notifier.h>
19 #include <linux/reboot.h>
20 #include <linux/slab.h>
21 #include <linux/uaccess.h>
22 #include <linux/workqueue.h>
23
24 #include <generated/utsrelease.h>
25
26 #include <misc/charlcd.h>
27
28 #define LCD_MINOR 156
29
30 #define DEFAULT_LCD_BWIDTH 40
31 #define DEFAULT_LCD_HWIDTH 64
32
33 /* Keep the backlight on this many seconds for each flash */
34 #define LCD_BL_TEMPO_PERIOD 4
35
36 #define LCD_FLAG_B 0x0004 /* Blink on */
37 #define LCD_FLAG_C 0x0008 /* Cursor on */
38 #define LCD_FLAG_D 0x0010 /* Display on */
39 #define LCD_FLAG_F 0x0020 /* Large font mode */
40 #define LCD_FLAG_N 0x0040 /* 2-rows mode */
41 #define LCD_FLAG_L 0x0080 /* Backlight enabled */
42
43 /* LCD commands */
44 #define LCD_CMD_DISPLAY_CLEAR 0x01 /* Clear entire display */
45
46 #define LCD_CMD_ENTRY_MODE 0x04 /* Set entry mode */
47 #define LCD_CMD_CURSOR_INC 0x02 /* Increment cursor */
48
49 #define LCD_CMD_DISPLAY_CTRL 0x08 /* Display control */
50 #define LCD_CMD_DISPLAY_ON 0x04 /* Set display on */
51 #define LCD_CMD_CURSOR_ON 0x02 /* Set cursor on */
52 #define LCD_CMD_BLINK_ON 0x01 /* Set blink on */
53
54 #define LCD_CMD_SHIFT 0x10 /* Shift cursor/display */
55 #define LCD_CMD_DISPLAY_SHIFT 0x08 /* Shift display instead of cursor */
56 #define LCD_CMD_SHIFT_RIGHT 0x04 /* Shift display/cursor to the right */
57
58 #define LCD_CMD_FUNCTION_SET 0x20 /* Set function */
59 #define LCD_CMD_DATA_LEN_8BITS 0x10 /* Set data length to 8 bits */
60 #define LCD_CMD_TWO_LINES 0x08 /* Set to two display lines */
61 #define LCD_CMD_FONT_5X10_DOTS 0x04 /* Set char font to 5x10 dots */
62
63 #define LCD_CMD_SET_CGRAM_ADDR 0x40 /* Set char generator RAM address */
64
65 #define LCD_CMD_SET_DDRAM_ADDR 0x80 /* Set display data RAM address */
66
67 #define LCD_ESCAPE_LEN 24 /* Max chars for LCD escape command */
68 #define LCD_ESCAPE_CHAR 27 /* Use char 27 for escape command */
69
70 struct charlcd_priv {
71 struct charlcd lcd;
72
73 struct delayed_work bl_work;
74 struct mutex bl_tempo_lock; /* Protects access to bl_tempo */
75 bool bl_tempo;
76
77 bool must_clear;
78
79 /* contains the LCD config state */
80 unsigned long int flags;
81
82 /* Contains the LCD X and Y offset */
83 struct {
84 unsigned long int x;
85 unsigned long int y;
86 } addr;
87
88 /* Current escape sequence and it's length or -1 if outside */
89 struct {
90 char buf[LCD_ESCAPE_LEN + 1];
91 int len;
92 } esc_seq;
93
94 unsigned long long drvdata[0];
95 };
96
97 #define to_priv(p) container_of(p, struct charlcd_priv, lcd)
98
99 /* Device single-open policy control */
100 static atomic_t charlcd_available = ATOMIC_INIT(1);
101
102 /* sleeps that many milliseconds with a reschedule */
103 static void long_sleep(int ms)
104 {
105 if (in_interrupt())
106 mdelay(ms);
107 else
108 schedule_timeout_interruptible(msecs_to_jiffies(ms));
109 }
110
111 /* turn the backlight on or off */
112 static void charlcd_backlight(struct charlcd *lcd, int on)
113 {
114 struct charlcd_priv *priv = to_priv(lcd);
115
116 if (!lcd->ops->backlight)
117 return;
118
119 mutex_lock(&priv->bl_tempo_lock);
120 if (!priv->bl_tempo)
121 lcd->ops->backlight(lcd, on);
122 mutex_unlock(&priv->bl_tempo_lock);
123 }
124
125 static void charlcd_bl_off(struct work_struct *work)
126 {
127 struct delayed_work *dwork = to_delayed_work(work);
128 struct charlcd_priv *priv =
129 container_of(dwork, struct charlcd_priv, bl_work);
130
131 mutex_lock(&priv->bl_tempo_lock);
132 if (priv->bl_tempo) {
133 priv->bl_tempo = false;
134 if (!(priv->flags & LCD_FLAG_L))
135 priv->lcd.ops->backlight(&priv->lcd, 0);
136 }
137 mutex_unlock(&priv->bl_tempo_lock);
138 }
139
140 /* turn the backlight on for a little while */
141 void charlcd_poke(struct charlcd *lcd)
142 {
143 struct charlcd_priv *priv = to_priv(lcd);
144
145 if (!lcd->ops->backlight)
146 return;
147
148 cancel_delayed_work_sync(&priv->bl_work);
149
150 mutex_lock(&priv->bl_tempo_lock);
151 if (!priv->bl_tempo && !(priv->flags & LCD_FLAG_L))
152 lcd->ops->backlight(lcd, 1);
153 priv->bl_tempo = true;
154 schedule_delayed_work(&priv->bl_work, LCD_BL_TEMPO_PERIOD * HZ);
155 mutex_unlock(&priv->bl_tempo_lock);
156 }
157 EXPORT_SYMBOL_GPL(charlcd_poke);
158
159 static void charlcd_gotoxy(struct charlcd *lcd)
160 {
161 struct charlcd_priv *priv = to_priv(lcd);
162 unsigned int addr;
163
164 /*
165 * we force the cursor to stay at the end of the
166 * line if it wants to go farther
167 */
168 addr = priv->addr.x < lcd->bwidth ? priv->addr.x & (lcd->hwidth - 1)
169 : lcd->bwidth - 1;
170 if (priv->addr.y & 1)
171 addr += lcd->hwidth;
172 if (priv->addr.y & 2)
173 addr += lcd->bwidth;
174 lcd->ops->write_cmd(lcd, LCD_CMD_SET_DDRAM_ADDR | addr);
175 }
176
177 static void charlcd_home(struct charlcd *lcd)
178 {
179 struct charlcd_priv *priv = to_priv(lcd);
180
181 priv->addr.x = 0;
182 priv->addr.y = 0;
183 charlcd_gotoxy(lcd);
184 }
185
186 static void charlcd_print(struct charlcd *lcd, char c)
187 {
188 struct charlcd_priv *priv = to_priv(lcd);
189
190 if (priv->addr.x < lcd->bwidth) {
191 if (lcd->char_conv)
192 c = lcd->char_conv[(unsigned char)c];
193 lcd->ops->write_data(lcd, c);
194 priv->addr.x++;
195 }
196 /* prevents the cursor from wrapping onto the next line */
197 if (priv->addr.x == lcd->bwidth)
198 charlcd_gotoxy(lcd);
199 }
200
201 static void charlcd_clear_fast(struct charlcd *lcd)
202 {
203 int pos;
204
205 charlcd_home(lcd);
206
207 if (lcd->ops->clear_fast)
208 lcd->ops->clear_fast(lcd);
209 else
210 for (pos = 0; pos < min(2, lcd->height) * lcd->hwidth; pos++)
211 lcd->ops->write_data(lcd, ' ');
212
213 charlcd_home(lcd);
214 }
215
216 /* clears the display and resets X/Y */
217 static void charlcd_clear_display(struct charlcd *lcd)
218 {
219 struct charlcd_priv *priv = to_priv(lcd);
220
221 lcd->ops->write_cmd(lcd, LCD_CMD_DISPLAY_CLEAR);
222 priv->addr.x = 0;
223 priv->addr.y = 0;
224 /* we must wait a few milliseconds (15) */
225 long_sleep(15);
226 }
227
228 static int charlcd_init_display(struct charlcd *lcd)
229 {
230 void (*write_cmd_raw)(struct charlcd *lcd, int cmd);
231 struct charlcd_priv *priv = to_priv(lcd);
232 u8 init;
233
234 if (lcd->ifwidth != 4 && lcd->ifwidth != 8)
235 return -EINVAL;
236
237 priv->flags = ((lcd->height > 1) ? LCD_FLAG_N : 0) | LCD_FLAG_D |
238 LCD_FLAG_C | LCD_FLAG_B;
239
240 long_sleep(20); /* wait 20 ms after power-up for the paranoid */
241
242 /*
243 * 8-bit mode, 1 line, small fonts; let's do it 3 times, to make sure
244 * the LCD is in 8-bit mode afterwards
245 */
246 init = LCD_CMD_FUNCTION_SET | LCD_CMD_DATA_LEN_8BITS;
247 if (lcd->ifwidth == 4) {
248 init >>= 4;
249 write_cmd_raw = lcd->ops->write_cmd_raw4;
250 } else {
251 write_cmd_raw = lcd->ops->write_cmd;
252 }
253 write_cmd_raw(lcd, init);
254 long_sleep(10);
255 write_cmd_raw(lcd, init);
256 long_sleep(10);
257 write_cmd_raw(lcd, init);
258 long_sleep(10);
259
260 if (lcd->ifwidth == 4) {
261 /* Switch to 4-bit mode, 1 line, small fonts */
262 lcd->ops->write_cmd_raw4(lcd, LCD_CMD_FUNCTION_SET >> 4);
263 long_sleep(10);
264 }
265
266 /* set font height and lines number */
267 lcd->ops->write_cmd(lcd,
268 LCD_CMD_FUNCTION_SET |
269 ((lcd->ifwidth == 8) ? LCD_CMD_DATA_LEN_8BITS : 0) |
270 ((priv->flags & LCD_FLAG_F) ? LCD_CMD_FONT_5X10_DOTS : 0) |
271 ((priv->flags & LCD_FLAG_N) ? LCD_CMD_TWO_LINES : 0));
272 long_sleep(10);
273
274 /* display off, cursor off, blink off */
275 lcd->ops->write_cmd(lcd, LCD_CMD_DISPLAY_CTRL);
276 long_sleep(10);
277
278 lcd->ops->write_cmd(lcd,
279 LCD_CMD_DISPLAY_CTRL | /* set display mode */
280 ((priv->flags & LCD_FLAG_D) ? LCD_CMD_DISPLAY_ON : 0) |
281 ((priv->flags & LCD_FLAG_C) ? LCD_CMD_CURSOR_ON : 0) |
282 ((priv->flags & LCD_FLAG_B) ? LCD_CMD_BLINK_ON : 0));
283
284 charlcd_backlight(lcd, (priv->flags & LCD_FLAG_L) ? 1 : 0);
285
286 long_sleep(10);
287
288 /* entry mode set : increment, cursor shifting */
289 lcd->ops->write_cmd(lcd, LCD_CMD_ENTRY_MODE | LCD_CMD_CURSOR_INC);
290
291 charlcd_clear_display(lcd);
292 return 0;
293 }
294
295 /*
296 * These are the file operation function for user access to /dev/lcd
297 * This function can also be called from inside the kernel, by
298 * setting file and ppos to NULL.
299 *
300 */
301
302 static inline int handle_lcd_special_code(struct charlcd *lcd)
303 {
304 struct charlcd_priv *priv = to_priv(lcd);
305
306 /* LCD special codes */
307
308 int processed = 0;
309
310 char *esc = priv->esc_seq.buf + 2;
311 int oldflags = priv->flags;
312
313 /* check for display mode flags */
314 switch (*esc) {
315 case 'D': /* Display ON */
316 priv->flags |= LCD_FLAG_D;
317 processed = 1;
318 break;
319 case 'd': /* Display OFF */
320 priv->flags &= ~LCD_FLAG_D;
321 processed = 1;
322 break;
323 case 'C': /* Cursor ON */
324 priv->flags |= LCD_FLAG_C;
325 processed = 1;
326 break;
327 case 'c': /* Cursor OFF */
328 priv->flags &= ~LCD_FLAG_C;
329 processed = 1;
330 break;
331 case 'B': /* Blink ON */
332 priv->flags |= LCD_FLAG_B;
333 processed = 1;
334 break;
335 case 'b': /* Blink OFF */
336 priv->flags &= ~LCD_FLAG_B;
337 processed = 1;
338 break;
339 case '+': /* Back light ON */
340 priv->flags |= LCD_FLAG_L;
341 processed = 1;
342 break;
343 case '-': /* Back light OFF */
344 priv->flags &= ~LCD_FLAG_L;
345 processed = 1;
346 break;
347 case '*': /* Flash back light */
348 charlcd_poke(lcd);
349 processed = 1;
350 break;
351 case 'f': /* Small Font */
352 priv->flags &= ~LCD_FLAG_F;
353 processed = 1;
354 break;
355 case 'F': /* Large Font */
356 priv->flags |= LCD_FLAG_F;
357 processed = 1;
358 break;
359 case 'n': /* One Line */
360 priv->flags &= ~LCD_FLAG_N;
361 processed = 1;
362 break;
363 case 'N': /* Two Lines */
364 priv->flags |= LCD_FLAG_N;
365 break;
366 case 'l': /* Shift Cursor Left */
367 if (priv->addr.x > 0) {
368 /* back one char if not at end of line */
369 if (priv->addr.x < lcd->bwidth)
370 lcd->ops->write_cmd(lcd, LCD_CMD_SHIFT);
371 priv->addr.x--;
372 }
373 processed = 1;
374 break;
375 case 'r': /* shift cursor right */
376 if (priv->addr.x < lcd->width) {
377 /* allow the cursor to pass the end of the line */
378 if (priv->addr.x < (lcd->bwidth - 1))
379 lcd->ops->write_cmd(lcd,
380 LCD_CMD_SHIFT | LCD_CMD_SHIFT_RIGHT);
381 priv->addr.x++;
382 }
383 processed = 1;
384 break;
385 case 'L': /* shift display left */
386 lcd->ops->write_cmd(lcd, LCD_CMD_SHIFT | LCD_CMD_DISPLAY_SHIFT);
387 processed = 1;
388 break;
389 case 'R': /* shift display right */
390 lcd->ops->write_cmd(lcd,
391 LCD_CMD_SHIFT | LCD_CMD_DISPLAY_SHIFT |
392 LCD_CMD_SHIFT_RIGHT);
393 processed = 1;
394 break;
395 case 'k': { /* kill end of line */
396 int x;
397
398 for (x = priv->addr.x; x < lcd->bwidth; x++)
399 lcd->ops->write_data(lcd, ' ');
400
401 /* restore cursor position */
402 charlcd_gotoxy(lcd);
403 processed = 1;
404 break;
405 }
406 case 'I': /* reinitialize display */
407 charlcd_init_display(lcd);
408 processed = 1;
409 break;
410 case 'G': {
411 /* Generator : LGcxxxxx...xx; must have <c> between '0'
412 * and '7', representing the numerical ASCII code of the
413 * redefined character, and <xx...xx> a sequence of 16
414 * hex digits representing 8 bytes for each character.
415 * Most LCDs will only use 5 lower bits of the 7 first
416 * bytes.
417 */
418
419 unsigned char cgbytes[8];
420 unsigned char cgaddr;
421 int cgoffset;
422 int shift;
423 char value;
424 int addr;
425
426 if (!strchr(esc, ';'))
427 break;
428
429 esc++;
430
431 cgaddr = *(esc++) - '0';
432 if (cgaddr > 7) {
433 processed = 1;
434 break;
435 }
436
437 cgoffset = 0;
438 shift = 0;
439 value = 0;
440 while (*esc && cgoffset < 8) {
441 shift ^= 4;
442 if (*esc >= '0' && *esc <= '9') {
443 value |= (*esc - '0') << shift;
444 } else if (*esc >= 'A' && *esc <= 'Z') {
445 value |= (*esc - 'A' + 10) << shift;
446 } else if (*esc >= 'a' && *esc <= 'z') {
447 value |= (*esc - 'a' + 10) << shift;
448 } else {
449 esc++;
450 continue;
451 }
452
453 if (shift == 0) {
454 cgbytes[cgoffset++] = value;
455 value = 0;
456 }
457
458 esc++;
459 }
460
461 lcd->ops->write_cmd(lcd, LCD_CMD_SET_CGRAM_ADDR | (cgaddr * 8));
462 for (addr = 0; addr < cgoffset; addr++)
463 lcd->ops->write_data(lcd, cgbytes[addr]);
464
465 /* ensures that we stop writing to CGRAM */
466 charlcd_gotoxy(lcd);
467 processed = 1;
468 break;
469 }
470 case 'x': /* gotoxy : LxXXX[yYYY]; */
471 case 'y': /* gotoxy : LyYYY[xXXX]; */
472 if (!strchr(esc, ';'))
473 break;
474
475 while (*esc) {
476 if (*esc == 'x') {
477 esc++;
478 if (kstrtoul(esc, 10, &priv->addr.x) < 0)
479 break;
480 } else if (*esc == 'y') {
481 esc++;
482 if (kstrtoul(esc, 10, &priv->addr.y) < 0)
483 break;
484 } else {
485 break;
486 }
487 }
488
489 charlcd_gotoxy(lcd);
490 processed = 1;
491 break;
492 }
493
494 /* TODO: This indent party here got ugly, clean it! */
495 /* Check whether one flag was changed */
496 if (oldflags == priv->flags)
497 return processed;
498
499 /* check whether one of B,C,D flags were changed */
500 if ((oldflags ^ priv->flags) &
501 (LCD_FLAG_B | LCD_FLAG_C | LCD_FLAG_D))
502 /* set display mode */
503 lcd->ops->write_cmd(lcd,
504 LCD_CMD_DISPLAY_CTRL |
505 ((priv->flags & LCD_FLAG_D) ? LCD_CMD_DISPLAY_ON : 0) |
506 ((priv->flags & LCD_FLAG_C) ? LCD_CMD_CURSOR_ON : 0) |
507 ((priv->flags & LCD_FLAG_B) ? LCD_CMD_BLINK_ON : 0));
508 /* check whether one of F,N flags was changed */
509 else if ((oldflags ^ priv->flags) & (LCD_FLAG_F | LCD_FLAG_N))
510 lcd->ops->write_cmd(lcd,
511 LCD_CMD_FUNCTION_SET |
512 ((lcd->ifwidth == 8) ? LCD_CMD_DATA_LEN_8BITS : 0) |
513 ((priv->flags & LCD_FLAG_F) ? LCD_CMD_FONT_5X10_DOTS : 0) |
514 ((priv->flags & LCD_FLAG_N) ? LCD_CMD_TWO_LINES : 0));
515 /* check whether L flag was changed */
516 else if ((oldflags ^ priv->flags) & LCD_FLAG_L)
517 charlcd_backlight(lcd, !!(priv->flags & LCD_FLAG_L));
518
519 return processed;
520 }
521
522 static void charlcd_write_char(struct charlcd *lcd, char c)
523 {
524 struct charlcd_priv *priv = to_priv(lcd);
525
526 /* first, we'll test if we're in escape mode */
527 if ((c != '\n') && priv->esc_seq.len >= 0) {
528 /* yes, let's add this char to the buffer */
529 priv->esc_seq.buf[priv->esc_seq.len++] = c;
530 priv->esc_seq.buf[priv->esc_seq.len] = 0;
531 } else {
532 /* aborts any previous escape sequence */
533 priv->esc_seq.len = -1;
534
535 switch (c) {
536 case LCD_ESCAPE_CHAR:
537 /* start of an escape sequence */
538 priv->esc_seq.len = 0;
539 priv->esc_seq.buf[priv->esc_seq.len] = 0;
540 break;
541 case '\b':
542 /* go back one char and clear it */
543 if (priv->addr.x > 0) {
544 /*
545 * check if we're not at the
546 * end of the line
547 */
548 if (priv->addr.x < lcd->bwidth)
549 /* back one char */
550 lcd->ops->write_cmd(lcd, LCD_CMD_SHIFT);
551 priv->addr.x--;
552 }
553 /* replace with a space */
554 lcd->ops->write_data(lcd, ' ');
555 /* back one char again */
556 lcd->ops->write_cmd(lcd, LCD_CMD_SHIFT);
557 break;
558 case '\014':
559 /* quickly clear the display */
560 charlcd_clear_fast(lcd);
561 break;
562 case '\n':
563 /*
564 * flush the remainder of the current line and
565 * go to the beginning of the next line
566 */
567 for (; priv->addr.x < lcd->bwidth; priv->addr.x++)
568 lcd->ops->write_data(lcd, ' ');
569 priv->addr.x = 0;
570 priv->addr.y = (priv->addr.y + 1) % lcd->height;
571 charlcd_gotoxy(lcd);
572 break;
573 case '\r':
574 /* go to the beginning of the same line */
575 priv->addr.x = 0;
576 charlcd_gotoxy(lcd);
577 break;
578 case '\t':
579 /* print a space instead of the tab */
580 charlcd_print(lcd, ' ');
581 break;
582 default:
583 /* simply print this char */
584 charlcd_print(lcd, c);
585 break;
586 }
587 }
588
589 /*
590 * now we'll see if we're in an escape mode and if the current
591 * escape sequence can be understood.
592 */
593 if (priv->esc_seq.len >= 2) {
594 int processed = 0;
595
596 if (!strcmp(priv->esc_seq.buf, "[2J")) {
597 /* clear the display */
598 charlcd_clear_fast(lcd);
599 processed = 1;
600 } else if (!strcmp(priv->esc_seq.buf, "[H")) {
601 /* cursor to home */
602 charlcd_home(lcd);
603 processed = 1;
604 }
605 /* codes starting with ^[[L */
606 else if ((priv->esc_seq.len >= 3) &&
607 (priv->esc_seq.buf[0] == '[') &&
608 (priv->esc_seq.buf[1] == 'L')) {
609 processed = handle_lcd_special_code(lcd);
610 }
611
612 /* LCD special escape codes */
613 /*
614 * flush the escape sequence if it's been processed
615 * or if it is getting too long.
616 */
617 if (processed || (priv->esc_seq.len >= LCD_ESCAPE_LEN))
618 priv->esc_seq.len = -1;
619 } /* escape codes */
620 }
621
622 static struct charlcd *the_charlcd;
623
624 static ssize_t charlcd_write(struct file *file, const char __user *buf,
625 size_t count, loff_t *ppos)
626 {
627 const char __user *tmp = buf;
628 char c;
629
630 for (; count-- > 0; (*ppos)++, tmp++) {
631 if (!in_interrupt() && (((count + 1) & 0x1f) == 0))
632 /*
633 * let's be a little nice with other processes
634 * that need some CPU
635 */
636 schedule();
637
638 if (get_user(c, tmp))
639 return -EFAULT;
640
641 charlcd_write_char(the_charlcd, c);
642 }
643
644 return tmp - buf;
645 }
646
647 static int charlcd_open(struct inode *inode, struct file *file)
648 {
649 struct charlcd_priv *priv = to_priv(the_charlcd);
650 int ret;
651
652 ret = -EBUSY;
653 if (!atomic_dec_and_test(&charlcd_available))
654 goto fail; /* open only once at a time */
655
656 ret = -EPERM;
657 if (file->f_mode & FMODE_READ) /* device is write-only */
658 goto fail;
659
660 if (priv->must_clear) {
661 charlcd_clear_display(&priv->lcd);
662 priv->must_clear = false;
663 }
664 return nonseekable_open(inode, file);
665
666 fail:
667 atomic_inc(&charlcd_available);
668 return ret;
669 }
670
671 static int charlcd_release(struct inode *inode, struct file *file)
672 {
673 atomic_inc(&charlcd_available);
674 return 0;
675 }
676
677 static const struct file_operations charlcd_fops = {
678 .write = charlcd_write,
679 .open = charlcd_open,
680 .release = charlcd_release,
681 .llseek = no_llseek,
682 };
683
684 static struct miscdevice charlcd_dev = {
685 .minor = LCD_MINOR,
686 .name = "lcd",
687 .fops = &charlcd_fops,
688 };
689
690 static void charlcd_puts(struct charlcd *lcd, const char *s)
691 {
692 const char *tmp = s;
693 int count = strlen(s);
694
695 for (; count-- > 0; tmp++) {
696 if (!in_interrupt() && (((count + 1) & 0x1f) == 0))
697 /*
698 * let's be a little nice with other processes
699 * that need some CPU
700 */
701 schedule();
702
703 charlcd_write_char(lcd, *tmp);
704 }
705 }
706
707 /* initialize the LCD driver */
708 static int charlcd_init(struct charlcd *lcd)
709 {
710 struct charlcd_priv *priv = to_priv(lcd);
711 int ret;
712
713 if (lcd->ops->backlight) {
714 mutex_init(&priv->bl_tempo_lock);
715 INIT_DELAYED_WORK(&priv->bl_work, charlcd_bl_off);
716 }
717
718 /*
719 * before this line, we must NOT send anything to the display.
720 * Since charlcd_init_display() needs to write data, we have to
721 * enable mark the LCD initialized just before.
722 */
723 ret = charlcd_init_display(lcd);
724 if (ret)
725 return ret;
726
727 /* display a short message */
728 #ifdef CONFIG_PANEL_CHANGE_MESSAGE
729 #ifdef CONFIG_PANEL_BOOT_MESSAGE
730 charlcd_puts(lcd, "\x1b[Lc\x1b[Lb\x1b[L*" CONFIG_PANEL_BOOT_MESSAGE);
731 #endif
732 #else
733 charlcd_puts(lcd, "\x1b[Lc\x1b[Lb\x1b[L*Linux-" UTS_RELEASE "\n");
734 #endif
735 /* clear the display on the next device opening */
736 priv->must_clear = true;
737 charlcd_home(lcd);
738 return 0;
739 }
740
741 struct charlcd *charlcd_alloc(unsigned int drvdata_size)
742 {
743 struct charlcd_priv *priv;
744 struct charlcd *lcd;
745
746 priv = kzalloc(sizeof(*priv) + drvdata_size, GFP_KERNEL);
747 if (!priv)
748 return NULL;
749
750 priv->esc_seq.len = -1;
751
752 lcd = &priv->lcd;
753 lcd->ifwidth = 8;
754 lcd->bwidth = DEFAULT_LCD_BWIDTH;
755 lcd->hwidth = DEFAULT_LCD_HWIDTH;
756 lcd->drvdata = priv->drvdata;
757
758 return lcd;
759 }
760 EXPORT_SYMBOL_GPL(charlcd_alloc);
761
762 static int panel_notify_sys(struct notifier_block *this, unsigned long code,
763 void *unused)
764 {
765 struct charlcd *lcd = the_charlcd;
766
767 switch (code) {
768 case SYS_DOWN:
769 charlcd_puts(lcd,
770 "\x0cReloading\nSystem...\x1b[Lc\x1b[Lb\x1b[L+");
771 break;
772 case SYS_HALT:
773 charlcd_puts(lcd, "\x0cSystem Halted.\x1b[Lc\x1b[Lb\x1b[L+");
774 break;
775 case SYS_POWER_OFF:
776 charlcd_puts(lcd, "\x0cPower off.\x1b[Lc\x1b[Lb\x1b[L+");
777 break;
778 default:
779 break;
780 }
781 return NOTIFY_DONE;
782 }
783
784 static struct notifier_block panel_notifier = {
785 panel_notify_sys,
786 NULL,
787 0
788 };
789
790 int charlcd_register(struct charlcd *lcd)
791 {
792 int ret;
793
794 ret = charlcd_init(lcd);
795 if (ret)
796 return ret;
797
798 ret = misc_register(&charlcd_dev);
799 if (ret)
800 return ret;
801
802 the_charlcd = lcd;
803 register_reboot_notifier(&panel_notifier);
804 return 0;
805 }
806 EXPORT_SYMBOL_GPL(charlcd_register);
807
808 int charlcd_unregister(struct charlcd *lcd)
809 {
810 struct charlcd_priv *priv = to_priv(lcd);
811
812 unregister_reboot_notifier(&panel_notifier);
813 charlcd_puts(lcd, "\x0cLCD driver unloaded.\x1b[Lc\x1b[Lb\x1b[L-");
814 misc_deregister(&charlcd_dev);
815 the_charlcd = NULL;
816 if (lcd->ops->backlight) {
817 cancel_delayed_work_sync(&priv->bl_work);
818 priv->lcd.ops->backlight(&priv->lcd, 0);
819 }
820
821 return 0;
822 }
823 EXPORT_SYMBOL_GPL(charlcd_unregister);
824
825 MODULE_LICENSE("GPL");
Linux with added FPC-III support