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"); 826