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treewide: remove redundant IS_ERR() before error code check
[linux/fpc-iii.git] / drivers / auxdisplay / charlcd.c
blob874c259a88291880d368440437444dcf7e7b625d
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Character LCD driver for Linux
4 *
5 * Copyright (C) 2000-2008, Willy Tarreau <w@1wt.eu>
6 * Copyright (C) 2016-2017 Glider bvba
7 */
8
9 #include <linux/atomic.h>
10 #include <linux/ctype.h>
11 #include <linux/delay.h>
12 #include <linux/fs.h>
13 #include <linux/miscdevice.h>
14 #include <linux/module.h>
15 #include <linux/notifier.h>
16 #include <linux/reboot.h>
17 #include <linux/slab.h>
18 #include <linux/uaccess.h>
19 #include <linux/workqueue.h>
20
21 #include <generated/utsrelease.h>
22
23 #include "charlcd.h"
24
25 #define LCD_MINOR 156
26
27 #define DEFAULT_LCD_BWIDTH 40
28 #define DEFAULT_LCD_HWIDTH 64
29
30 /* Keep the backlight on this many seconds for each flash */
31 #define LCD_BL_TEMPO_PERIOD 4
32
33 #define LCD_FLAG_B 0x0004 /* Blink on */
34 #define LCD_FLAG_C 0x0008 /* Cursor on */
35 #define LCD_FLAG_D 0x0010 /* Display on */
36 #define LCD_FLAG_F 0x0020 /* Large font mode */
37 #define LCD_FLAG_N 0x0040 /* 2-rows mode */
38 #define LCD_FLAG_L 0x0080 /* Backlight enabled */
39
40 /* LCD commands */
41 #define LCD_CMD_DISPLAY_CLEAR 0x01 /* Clear entire display */
42
43 #define LCD_CMD_ENTRY_MODE 0x04 /* Set entry mode */
44 #define LCD_CMD_CURSOR_INC 0x02 /* Increment cursor */
45
46 #define LCD_CMD_DISPLAY_CTRL 0x08 /* Display control */
47 #define LCD_CMD_DISPLAY_ON 0x04 /* Set display on */
48 #define LCD_CMD_CURSOR_ON 0x02 /* Set cursor on */
49 #define LCD_CMD_BLINK_ON 0x01 /* Set blink on */
50
51 #define LCD_CMD_SHIFT 0x10 /* Shift cursor/display */
52 #define LCD_CMD_DISPLAY_SHIFT 0x08 /* Shift display instead of cursor */
53 #define LCD_CMD_SHIFT_RIGHT 0x04 /* Shift display/cursor to the right */
54
55 #define LCD_CMD_FUNCTION_SET 0x20 /* Set function */
56 #define LCD_CMD_DATA_LEN_8BITS 0x10 /* Set data length to 8 bits */
57 #define LCD_CMD_TWO_LINES 0x08 /* Set to two display lines */
58 #define LCD_CMD_FONT_5X10_DOTS 0x04 /* Set char font to 5x10 dots */
59
60 #define LCD_CMD_SET_CGRAM_ADDR 0x40 /* Set char generator RAM address */
61
62 #define LCD_CMD_SET_DDRAM_ADDR 0x80 /* Set display data RAM address */
63
64 #define LCD_ESCAPE_LEN 24 /* Max chars for LCD escape command */
65 #define LCD_ESCAPE_CHAR 27 /* Use char 27 for escape command */
66
67 struct charlcd_priv {
68 struct charlcd lcd;
69
70 struct delayed_work bl_work;
71 struct mutex bl_tempo_lock; /* Protects access to bl_tempo */
72 bool bl_tempo;
73
74 bool must_clear;
75
76 /* contains the LCD config state */
77 unsigned long int flags;
78
79 /* Contains the LCD X and Y offset */
80 struct {
81 unsigned long int x;
82 unsigned long int y;
83 } addr;
84
85 /* Current escape sequence and it's length or -1 if outside */
86 struct {
87 char buf[LCD_ESCAPE_LEN + 1];
88 int len;
89 } esc_seq;
90
91 unsigned long long drvdata[0];
92 };
93
94 #define charlcd_to_priv(p) container_of(p, struct charlcd_priv, lcd)
95
96 /* Device single-open policy control */
97 static atomic_t charlcd_available = ATOMIC_INIT(1);
98
99 /* sleeps that many milliseconds with a reschedule */
100 static void long_sleep(int ms)
101 {
102 schedule_timeout_interruptible(msecs_to_jiffies(ms));
103 }
104
105 /* turn the backlight on or off */
106 static void charlcd_backlight(struct charlcd *lcd, int on)
107 {
108 struct charlcd_priv *priv = charlcd_to_priv(lcd);
109
110 if (!lcd->ops->backlight)
111 return;
112
113 mutex_lock(&priv->bl_tempo_lock);
114 if (!priv->bl_tempo)
115 lcd->ops->backlight(lcd, on);
116 mutex_unlock(&priv->bl_tempo_lock);
117 }
118
119 static void charlcd_bl_off(struct work_struct *work)
120 {
121 struct delayed_work *dwork = to_delayed_work(work);
122 struct charlcd_priv *priv =
123 container_of(dwork, struct charlcd_priv, bl_work);
124
125 mutex_lock(&priv->bl_tempo_lock);
126 if (priv->bl_tempo) {
127 priv->bl_tempo = false;
128 if (!(priv->flags & LCD_FLAG_L))
129 priv->lcd.ops->backlight(&priv->lcd, 0);
130 }
131 mutex_unlock(&priv->bl_tempo_lock);
132 }
133
134 /* turn the backlight on for a little while */
135 void charlcd_poke(struct charlcd *lcd)
136 {
137 struct charlcd_priv *priv = charlcd_to_priv(lcd);
138
139 if (!lcd->ops->backlight)
140 return;
141
142 cancel_delayed_work_sync(&priv->bl_work);
143
144 mutex_lock(&priv->bl_tempo_lock);
145 if (!priv->bl_tempo && !(priv->flags & LCD_FLAG_L))
146 lcd->ops->backlight(lcd, 1);
147 priv->bl_tempo = true;
148 schedule_delayed_work(&priv->bl_work, LCD_BL_TEMPO_PERIOD * HZ);
149 mutex_unlock(&priv->bl_tempo_lock);
150 }
151 EXPORT_SYMBOL_GPL(charlcd_poke);
152
153 static void charlcd_gotoxy(struct charlcd *lcd)
154 {
155 struct charlcd_priv *priv = charlcd_to_priv(lcd);
156 unsigned int addr;
157
158 /*
159 * we force the cursor to stay at the end of the
160 * line if it wants to go farther
161 */
162 addr = priv->addr.x < lcd->bwidth ? priv->addr.x & (lcd->hwidth - 1)
163 : lcd->bwidth - 1;
164 if (priv->addr.y & 1)
165 addr += lcd->hwidth;
166 if (priv->addr.y & 2)
167 addr += lcd->bwidth;
168 lcd->ops->write_cmd(lcd, LCD_CMD_SET_DDRAM_ADDR | addr);
169 }
170
171 static void charlcd_home(struct charlcd *lcd)
172 {
173 struct charlcd_priv *priv = charlcd_to_priv(lcd);
174
175 priv->addr.x = 0;
176 priv->addr.y = 0;
177 charlcd_gotoxy(lcd);
178 }
179
180 static void charlcd_print(struct charlcd *lcd, char c)
181 {
182 struct charlcd_priv *priv = charlcd_to_priv(lcd);
183
184 if (priv->addr.x < lcd->bwidth) {
185 if (lcd->char_conv)
186 c = lcd->char_conv[(unsigned char)c];
187 lcd->ops->write_data(lcd, c);
188 priv->addr.x++;
189
190 /* prevents the cursor from wrapping onto the next line */
191 if (priv->addr.x == lcd->bwidth)
192 charlcd_gotoxy(lcd);
193 }
194 }
195
196 static void charlcd_clear_fast(struct charlcd *lcd)
197 {
198 int pos;
199
200 charlcd_home(lcd);
201
202 if (lcd->ops->clear_fast)
203 lcd->ops->clear_fast(lcd);
204 else
205 for (pos = 0; pos < min(2, lcd->height) * lcd->hwidth; pos++)
206 lcd->ops->write_data(lcd, ' ');
207
208 charlcd_home(lcd);
209 }
210
211 /* clears the display and resets X/Y */
212 static void charlcd_clear_display(struct charlcd *lcd)
213 {
214 struct charlcd_priv *priv = charlcd_to_priv(lcd);
215
216 lcd->ops->write_cmd(lcd, LCD_CMD_DISPLAY_CLEAR);
217 priv->addr.x = 0;
218 priv->addr.y = 0;
219 /* we must wait a few milliseconds (15) */
220 long_sleep(15);
221 }
222
223 static int charlcd_init_display(struct charlcd *lcd)
224 {
225 void (*write_cmd_raw)(struct charlcd *lcd, int cmd);
226 struct charlcd_priv *priv = charlcd_to_priv(lcd);
227 u8 init;
228
229 if (lcd->ifwidth != 4 && lcd->ifwidth != 8)
230 return -EINVAL;
231
232 priv->flags = ((lcd->height > 1) ? LCD_FLAG_N : 0) | LCD_FLAG_D |
233 LCD_FLAG_C | LCD_FLAG_B;
234
235 long_sleep(20); /* wait 20 ms after power-up for the paranoid */
236
237 /*
238 * 8-bit mode, 1 line, small fonts; let's do it 3 times, to make sure
239 * the LCD is in 8-bit mode afterwards
240 */
241 init = LCD_CMD_FUNCTION_SET | LCD_CMD_DATA_LEN_8BITS;
242 if (lcd->ifwidth == 4) {
243 init >>= 4;
244 write_cmd_raw = lcd->ops->write_cmd_raw4;
245 } else {
246 write_cmd_raw = lcd->ops->write_cmd;
247 }
248 write_cmd_raw(lcd, init);
249 long_sleep(10);
250 write_cmd_raw(lcd, init);
251 long_sleep(10);
252 write_cmd_raw(lcd, init);
253 long_sleep(10);
254
255 if (lcd->ifwidth == 4) {
256 /* Switch to 4-bit mode, 1 line, small fonts */
257 lcd->ops->write_cmd_raw4(lcd, LCD_CMD_FUNCTION_SET >> 4);
258 long_sleep(10);
259 }
260
261 /* set font height and lines number */
262 lcd->ops->write_cmd(lcd,
263 LCD_CMD_FUNCTION_SET |
264 ((lcd->ifwidth == 8) ? LCD_CMD_DATA_LEN_8BITS : 0) |
265 ((priv->flags & LCD_FLAG_F) ? LCD_CMD_FONT_5X10_DOTS : 0) |
266 ((priv->flags & LCD_FLAG_N) ? LCD_CMD_TWO_LINES : 0));
267 long_sleep(10);
268
269 /* display off, cursor off, blink off */
270 lcd->ops->write_cmd(lcd, LCD_CMD_DISPLAY_CTRL);
271 long_sleep(10);
272
273 lcd->ops->write_cmd(lcd,
274 LCD_CMD_DISPLAY_CTRL | /* set display mode */
275 ((priv->flags & LCD_FLAG_D) ? LCD_CMD_DISPLAY_ON : 0) |
276 ((priv->flags & LCD_FLAG_C) ? LCD_CMD_CURSOR_ON : 0) |
277 ((priv->flags & LCD_FLAG_B) ? LCD_CMD_BLINK_ON : 0));
278
279 charlcd_backlight(lcd, (priv->flags & LCD_FLAG_L) ? 1 : 0);
280
281 long_sleep(10);
282
283 /* entry mode set : increment, cursor shifting */
284 lcd->ops->write_cmd(lcd, LCD_CMD_ENTRY_MODE | LCD_CMD_CURSOR_INC);
285
286 charlcd_clear_display(lcd);
287 return 0;
288 }
289
290 /*
291 * Parses a movement command of the form "(.*);", where the group can be
292 * any number of subcommands of the form "(x|y)[0-9]+".
293 *
294 * Returns whether the command is valid. The position arguments are
295 * only written if the parsing was successful.
296 *
297 * For instance:
298 * - ";" returns (<original x>, <original y>).
299 * - "x1;" returns (1, <original y>).
300 * - "y2x1;" returns (1, 2).
301 * - "x12y34x56;" returns (56, 34).
302 * - "" fails.
303 * - "x" fails.
304 * - "x;" fails.
305 * - "x1" fails.
306 * - "xy12;" fails.
307 * - "x12yy12;" fails.
308 * - "xx" fails.
309 */
310 static bool parse_xy(const char *s, unsigned long *x, unsigned long *y)
311 {
312 unsigned long new_x = *x;
313 unsigned long new_y = *y;
314 char *p;
315
316 for (;;) {
317 if (!*s)
318 return false;
319
320 if (*s == ';')
321 break;
322
323 if (*s == 'x') {
324 new_x = simple_strtoul(s + 1, &p, 10);
325 if (p == s + 1)
326 return false;
327 s = p;
328 } else if (*s == 'y') {
329 new_y = simple_strtoul(s + 1, &p, 10);
330 if (p == s + 1)
331 return false;
332 s = p;
333 } else {
334 return false;
335 }
336 }
337
338 *x = new_x;
339 *y = new_y;
340 return true;
341 }
342
343 /*
344 * These are the file operation function for user access to /dev/lcd
345 * This function can also be called from inside the kernel, by
346 * setting file and ppos to NULL.
347 *
348 */
349
350 static inline int handle_lcd_special_code(struct charlcd *lcd)
351 {
352 struct charlcd_priv *priv = charlcd_to_priv(lcd);
353
354 /* LCD special codes */
355
356 int processed = 0;
357
358 char *esc = priv->esc_seq.buf + 2;
359 int oldflags = priv->flags;
360
361 /* check for display mode flags */
362 switch (*esc) {
363 case 'D': /* Display ON */
364 priv->flags |= LCD_FLAG_D;
365 processed = 1;
366 break;
367 case 'd': /* Display OFF */
368 priv->flags &= ~LCD_FLAG_D;
369 processed = 1;
370 break;
371 case 'C': /* Cursor ON */
372 priv->flags |= LCD_FLAG_C;
373 processed = 1;
374 break;
375 case 'c': /* Cursor OFF */
376 priv->flags &= ~LCD_FLAG_C;
377 processed = 1;
378 break;
379 case 'B': /* Blink ON */
380 priv->flags |= LCD_FLAG_B;
381 processed = 1;
382 break;
383 case 'b': /* Blink OFF */
384 priv->flags &= ~LCD_FLAG_B;
385 processed = 1;
386 break;
387 case '+': /* Back light ON */
388 priv->flags |= LCD_FLAG_L;
389 processed = 1;
390 break;
391 case '-': /* Back light OFF */
392 priv->flags &= ~LCD_FLAG_L;
393 processed = 1;
394 break;
395 case '*': /* Flash back light */
396 charlcd_poke(lcd);
397 processed = 1;
398 break;
399 case 'f': /* Small Font */
400 priv->flags &= ~LCD_FLAG_F;
401 processed = 1;
402 break;
403 case 'F': /* Large Font */
404 priv->flags |= LCD_FLAG_F;
405 processed = 1;
406 break;
407 case 'n': /* One Line */
408 priv->flags &= ~LCD_FLAG_N;
409 processed = 1;
410 break;
411 case 'N': /* Two Lines */
412 priv->flags |= LCD_FLAG_N;
413 processed = 1;
414 break;
415 case 'l': /* Shift Cursor Left */
416 if (priv->addr.x > 0) {
417 /* back one char if not at end of line */
418 if (priv->addr.x < lcd->bwidth)
419 lcd->ops->write_cmd(lcd, LCD_CMD_SHIFT);
420 priv->addr.x--;
421 }
422 processed = 1;
423 break;
424 case 'r': /* shift cursor right */
425 if (priv->addr.x < lcd->width) {
426 /* allow the cursor to pass the end of the line */
427 if (priv->addr.x < (lcd->bwidth - 1))
428 lcd->ops->write_cmd(lcd,
429 LCD_CMD_SHIFT | LCD_CMD_SHIFT_RIGHT);
430 priv->addr.x++;
431 }
432 processed = 1;
433 break;
434 case 'L': /* shift display left */
435 lcd->ops->write_cmd(lcd, LCD_CMD_SHIFT | LCD_CMD_DISPLAY_SHIFT);
436 processed = 1;
437 break;
438 case 'R': /* shift display right */
439 lcd->ops->write_cmd(lcd,
440 LCD_CMD_SHIFT | LCD_CMD_DISPLAY_SHIFT |
441 LCD_CMD_SHIFT_RIGHT);
442 processed = 1;
443 break;
444 case 'k': { /* kill end of line */
445 int x;
446
447 for (x = priv->addr.x; x < lcd->bwidth; x++)
448 lcd->ops->write_data(lcd, ' ');
449
450 /* restore cursor position */
451 charlcd_gotoxy(lcd);
452 processed = 1;
453 break;
454 }
455 case 'I': /* reinitialize display */
456 charlcd_init_display(lcd);
457 processed = 1;
458 break;
459 case 'G': {
460 /* Generator : LGcxxxxx...xx; must have <c> between '0'
461 * and '7', representing the numerical ASCII code of the
462 * redefined character, and <xx...xx> a sequence of 16
463 * hex digits representing 8 bytes for each character.
464 * Most LCDs will only use 5 lower bits of the 7 first
465 * bytes.
466 */
467
468 unsigned char cgbytes[8];
469 unsigned char cgaddr;
470 int cgoffset;
471 int shift;
472 char value;
473 int addr;
474
475 if (!strchr(esc, ';'))
476 break;
477
478 esc++;
479
480 cgaddr = *(esc++) - '0';
481 if (cgaddr > 7) {
482 processed = 1;
483 break;
484 }
485
486 cgoffset = 0;
487 shift = 0;
488 value = 0;
489 while (*esc && cgoffset < 8) {
490 shift ^= 4;
491 if (*esc >= '0' && *esc <= '9') {
492 value |= (*esc - '0') << shift;
493 } else if (*esc >= 'A' && *esc <= 'F') {
494 value |= (*esc - 'A' + 10) << shift;
495 } else if (*esc >= 'a' && *esc <= 'f') {
496 value |= (*esc - 'a' + 10) << shift;
497 } else {
498 esc++;
499 continue;
500 }
501
502 if (shift == 0) {
503 cgbytes[cgoffset++] = value;
504 value = 0;
505 }
506
507 esc++;
508 }
509
510 lcd->ops->write_cmd(lcd, LCD_CMD_SET_CGRAM_ADDR | (cgaddr * 8));
511 for (addr = 0; addr < cgoffset; addr++)
512 lcd->ops->write_data(lcd, cgbytes[addr]);
513
514 /* ensures that we stop writing to CGRAM */
515 charlcd_gotoxy(lcd);
516 processed = 1;
517 break;
518 }
519 case 'x': /* gotoxy : LxXXX[yYYY]; */
520 case 'y': /* gotoxy : LyYYY[xXXX]; */
521 if (priv->esc_seq.buf[priv->esc_seq.len - 1] != ';')
522 break;
523
524 /* If the command is valid, move to the new address */
525 if (parse_xy(esc, &priv->addr.x, &priv->addr.y))
526 charlcd_gotoxy(lcd);
527
528 /* Regardless of its validity, mark as processed */
529 processed = 1;
530 break;
531 }
532
533 /* TODO: This indent party here got ugly, clean it! */
534 /* Check whether one flag was changed */
535 if (oldflags == priv->flags)
536 return processed;
537
538 /* check whether one of B,C,D flags were changed */
539 if ((oldflags ^ priv->flags) &
540 (LCD_FLAG_B | LCD_FLAG_C | LCD_FLAG_D))
541 /* set display mode */
542 lcd->ops->write_cmd(lcd,
543 LCD_CMD_DISPLAY_CTRL |
544 ((priv->flags & LCD_FLAG_D) ? LCD_CMD_DISPLAY_ON : 0) |
545 ((priv->flags & LCD_FLAG_C) ? LCD_CMD_CURSOR_ON : 0) |
546 ((priv->flags & LCD_FLAG_B) ? LCD_CMD_BLINK_ON : 0));
547 /* check whether one of F,N flags was changed */
548 else if ((oldflags ^ priv->flags) & (LCD_FLAG_F | LCD_FLAG_N))
549 lcd->ops->write_cmd(lcd,
550 LCD_CMD_FUNCTION_SET |
551 ((lcd->ifwidth == 8) ? LCD_CMD_DATA_LEN_8BITS : 0) |
552 ((priv->flags & LCD_FLAG_F) ? LCD_CMD_FONT_5X10_DOTS : 0) |
553 ((priv->flags & LCD_FLAG_N) ? LCD_CMD_TWO_LINES : 0));
554 /* check whether L flag was changed */
555 else if ((oldflags ^ priv->flags) & LCD_FLAG_L)
556 charlcd_backlight(lcd, !!(priv->flags & LCD_FLAG_L));
557
558 return processed;
559 }
560
561 static void charlcd_write_char(struct charlcd *lcd, char c)
562 {
563 struct charlcd_priv *priv = charlcd_to_priv(lcd);
564
565 /* first, we'll test if we're in escape mode */
566 if ((c != '\n') && priv->esc_seq.len >= 0) {
567 /* yes, let's add this char to the buffer */
568 priv->esc_seq.buf[priv->esc_seq.len++] = c;
569 priv->esc_seq.buf[priv->esc_seq.len] = '\0';
570 } else {
571 /* aborts any previous escape sequence */
572 priv->esc_seq.len = -1;
573
574 switch (c) {
575 case LCD_ESCAPE_CHAR:
576 /* start of an escape sequence */
577 priv->esc_seq.len = 0;
578 priv->esc_seq.buf[priv->esc_seq.len] = '\0';
579 break;
580 case '\b':
581 /* go back one char and clear it */
582 if (priv->addr.x > 0) {
583 /*
584 * check if we're not at the
585 * end of the line
586 */
587 if (priv->addr.x < lcd->bwidth)
588 /* back one char */
589 lcd->ops->write_cmd(lcd, LCD_CMD_SHIFT);
590 priv->addr.x--;
591 }
592 /* replace with a space */
593 lcd->ops->write_data(lcd, ' ');
594 /* back one char again */
595 lcd->ops->write_cmd(lcd, LCD_CMD_SHIFT);
596 break;
597 case '\f':
598 /* quickly clear the display */
599 charlcd_clear_fast(lcd);
600 break;
601 case '\n':
602 /*
603 * flush the remainder of the current line and
604 * go to the beginning of the next line
605 */
606 for (; priv->addr.x < lcd->bwidth; priv->addr.x++)
607 lcd->ops->write_data(lcd, ' ');
608 priv->addr.x = 0;
609 priv->addr.y = (priv->addr.y + 1) % lcd->height;
610 charlcd_gotoxy(lcd);
611 break;
612 case '\r':
613 /* go to the beginning of the same line */
614 priv->addr.x = 0;
615 charlcd_gotoxy(lcd);
616 break;
617 case '\t':
618 /* print a space instead of the tab */
619 charlcd_print(lcd, ' ');
620 break;
621 default:
622 /* simply print this char */
623 charlcd_print(lcd, c);
624 break;
625 }
626 }
627
628 /*
629 * now we'll see if we're in an escape mode and if the current
630 * escape sequence can be understood.
631 */
632 if (priv->esc_seq.len >= 2) {
633 int processed = 0;
634
635 if (!strcmp(priv->esc_seq.buf, "[2J")) {
636 /* clear the display */
637 charlcd_clear_fast(lcd);
638 processed = 1;
639 } else if (!strcmp(priv->esc_seq.buf, "[H")) {
640 /* cursor to home */
641 charlcd_home(lcd);
642 processed = 1;
643 }
644 /* codes starting with ^[[L */
645 else if ((priv->esc_seq.len >= 3) &&
646 (priv->esc_seq.buf[0] == '[') &&
647 (priv->esc_seq.buf[1] == 'L')) {
648 processed = handle_lcd_special_code(lcd);
649 }
650
651 /* LCD special escape codes */
652 /*
653 * flush the escape sequence if it's been processed
654 * or if it is getting too long.
655 */
656 if (processed || (priv->esc_seq.len >= LCD_ESCAPE_LEN))
657 priv->esc_seq.len = -1;
658 } /* escape codes */
659 }
660
661 static struct charlcd *the_charlcd;
662
663 static ssize_t charlcd_write(struct file *file, const char __user *buf,
664 size_t count, loff_t *ppos)
665 {
666 const char __user *tmp = buf;
667 char c;
668
669 for (; count-- > 0; (*ppos)++, tmp++) {
670 if (!in_interrupt() && (((count + 1) & 0x1f) == 0))
671 /*
672 * let's be a little nice with other processes
673 * that need some CPU
674 */
675 schedule();
676
677 if (get_user(c, tmp))
678 return -EFAULT;
679
680 charlcd_write_char(the_charlcd, c);
681 }
682
683 return tmp - buf;
684 }
685
686 static int charlcd_open(struct inode *inode, struct file *file)
687 {
688 struct charlcd_priv *priv = charlcd_to_priv(the_charlcd);
689 int ret;
690
691 ret = -EBUSY;
692 if (!atomic_dec_and_test(&charlcd_available))
693 goto fail; /* open only once at a time */
694
695 ret = -EPERM;
696 if (file->f_mode & FMODE_READ) /* device is write-only */
697 goto fail;
698
699 if (priv->must_clear) {
700 charlcd_clear_display(&priv->lcd);
701 priv->must_clear = false;
702 }
703 return nonseekable_open(inode, file);
704
705 fail:
706 atomic_inc(&charlcd_available);
707 return ret;
708 }
709
710 static int charlcd_release(struct inode *inode, struct file *file)
711 {
712 atomic_inc(&charlcd_available);
713 return 0;
714 }
715
716 static const struct file_operations charlcd_fops = {
717 .write = charlcd_write,
718 .open = charlcd_open,
719 .release = charlcd_release,
720 .llseek = no_llseek,
721 };
722
723 static struct miscdevice charlcd_dev = {
724 .minor = LCD_MINOR,
725 .name = "lcd",
726 .fops = &charlcd_fops,
727 };
728
729 static void charlcd_puts(struct charlcd *lcd, const char *s)
730 {
731 const char *tmp = s;
732 int count = strlen(s);
733
734 for (; count-- > 0; tmp++) {
735 if (!in_interrupt() && (((count + 1) & 0x1f) == 0))
736 /*
737 * let's be a little nice with other processes
738 * that need some CPU
739 */
740 schedule();
741
742 charlcd_write_char(lcd, *tmp);
743 }
744 }
745
746 #ifdef CONFIG_PANEL_BOOT_MESSAGE
747 #define LCD_INIT_TEXT CONFIG_PANEL_BOOT_MESSAGE
748 #else
749 #define LCD_INIT_TEXT "Linux-" UTS_RELEASE "\n"
750 #endif
751
752 #ifdef CONFIG_CHARLCD_BL_ON
753 #define LCD_INIT_BL "\x1b[L+"
754 #elif defined(CONFIG_CHARLCD_BL_FLASH)
755 #define LCD_INIT_BL "\x1b[L*"
756 #else
757 #define LCD_INIT_BL "\x1b[L-"
758 #endif
759
760 /* initialize the LCD driver */
761 static int charlcd_init(struct charlcd *lcd)
762 {
763 struct charlcd_priv *priv = charlcd_to_priv(lcd);
764 int ret;
765
766 if (lcd->ops->backlight) {
767 mutex_init(&priv->bl_tempo_lock);
768 INIT_DELAYED_WORK(&priv->bl_work, charlcd_bl_off);
769 }
770
771 /*
772 * before this line, we must NOT send anything to the display.
773 * Since charlcd_init_display() needs to write data, we have to
774 * enable mark the LCD initialized just before.
775 */
776 ret = charlcd_init_display(lcd);
777 if (ret)
778 return ret;
779
780 /* display a short message */
781 charlcd_puts(lcd, "\x1b[Lc\x1b[Lb" LCD_INIT_BL LCD_INIT_TEXT);
782
783 /* clear the display on the next device opening */
784 priv->must_clear = true;
785 charlcd_home(lcd);
786 return 0;
787 }
788
789 struct charlcd *charlcd_alloc(unsigned int drvdata_size)
790 {
791 struct charlcd_priv *priv;
792 struct charlcd *lcd;
793
794 priv = kzalloc(sizeof(*priv) + drvdata_size, GFP_KERNEL);
795 if (!priv)
796 return NULL;
797
798 priv->esc_seq.len = -1;
799
800 lcd = &priv->lcd;
801 lcd->ifwidth = 8;
802 lcd->bwidth = DEFAULT_LCD_BWIDTH;
803 lcd->hwidth = DEFAULT_LCD_HWIDTH;
804 lcd->drvdata = priv->drvdata;
805
806 return lcd;
807 }
808 EXPORT_SYMBOL_GPL(charlcd_alloc);
809
810 void charlcd_free(struct charlcd *lcd)
811 {
812 kfree(charlcd_to_priv(lcd));
813 }
814 EXPORT_SYMBOL_GPL(charlcd_free);
815
816 static int panel_notify_sys(struct notifier_block *this, unsigned long code,
817 void *unused)
818 {
819 struct charlcd *lcd = the_charlcd;
820
821 switch (code) {
822 case SYS_DOWN:
823 charlcd_puts(lcd,
824 "\x0cReloading\nSystem...\x1b[Lc\x1b[Lb\x1b[L+");
825 break;
826 case SYS_HALT:
827 charlcd_puts(lcd, "\x0cSystem Halted.\x1b[Lc\x1b[Lb\x1b[L+");
828 break;
829 case SYS_POWER_OFF:
830 charlcd_puts(lcd, "\x0cPower off.\x1b[Lc\x1b[Lb\x1b[L+");
831 break;
832 default:
833 break;
834 }
835 return NOTIFY_DONE;
836 }
837
838 static struct notifier_block panel_notifier = {
839 panel_notify_sys,
840 NULL,
841 0
842 };
843
844 int charlcd_register(struct charlcd *lcd)
845 {
846 int ret;
847
848 ret = charlcd_init(lcd);
849 if (ret)
850 return ret;
851
852 ret = misc_register(&charlcd_dev);
853 if (ret)
854 return ret;
855
856 the_charlcd = lcd;
857 register_reboot_notifier(&panel_notifier);
858 return 0;
859 }
860 EXPORT_SYMBOL_GPL(charlcd_register);
861
862 int charlcd_unregister(struct charlcd *lcd)
863 {
864 struct charlcd_priv *priv = charlcd_to_priv(lcd);
865
866 unregister_reboot_notifier(&panel_notifier);
867 charlcd_puts(lcd, "\x0cLCD driver unloaded.\x1b[Lc\x1b[Lb\x1b[L-");
868 misc_deregister(&charlcd_dev);
869 the_charlcd = NULL;
870 if (lcd->ops->backlight) {
871 cancel_delayed_work_sync(&priv->bl_work);
872 priv->lcd.ops->backlight(&priv->lcd, 0);
873 }
874
875 return 0;
876 }
877 EXPORT_SYMBOL_GPL(charlcd_unregister);
878
879 MODULE_LICENSE("GPL");
Linux with added FPC-III support