xref: /netbsd-src/sys/dev/ic/hd44780_subr.c (revision fad4c9f71477ae11cea2ee75ec82151ac770a534)
1 /* $NetBSD: hd44780_subr.c,v 1.9 2006/04/12 19:38:23 jmmv Exp $ */
2 
3 /*
4  * Copyright (c) 2002 Dennis I. Chernoivanov
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. The name of the author may not be used to endorse or promote products
16  *    derived from this software without specific prior written permission
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28  */
29 
30 /*
31  * Subroutines for Hitachi HD44870 style displays
32  */
33 
34 #include <sys/cdefs.h>
35 __KERNEL_RCSID(0, "$NetBSD: hd44780_subr.c,v 1.9 2006/04/12 19:38:23 jmmv Exp $");
36 
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/conf.h>
40 #include <sys/kernel.h>
41 #include <sys/malloc.h>
42 #include <sys/types.h>
43 #include <sys/ioccom.h>
44 
45 #include <machine/autoconf.h>
46 #include <machine/intr.h>
47 #include <machine/bus.h>
48 
49 #include <uvm/uvm_extern.h>
50 
51 #include <dev/wscons/wsdisplayvar.h>
52 #include <dev/wscons/wsconsio.h>
53 #include <dev/wscons/wscons_callbacks.h>
54 
55 #include <dev/ic/hd44780reg.h>
56 #include <dev/ic/hd44780var.h>
57 
58 #define COORD_TO_IDX(x, y)	((y) * sc->sc_cols + (x))
59 #define COORD_TO_DADDR(x, y)	((y) * HD_ROW2_ADDR + (x))
60 #define IDX_TO_ROW(idx)		((idx) / sc->sc_cols)
61 #define IDX_TO_COL(idx)		((idx) % sc->sc_cols)
62 #define IDX_TO_DADDR(idx)	(IDX_TO_ROW((idx)) * HD_ROW2_ADDR + \
63 				IDX_TO_COL((idx)))
64 #define DADDR_TO_ROW(daddr)	((daddr) / HD_ROW2_ADDR)
65 #define DADDR_TO_COL(daddr)	((daddr) % HD_ROW2_ADDR)
66 #define DADDR_TO_CHIPDADDR(daddr)	((daddr) % (HD_ROW2_ADDR * 2))
67 #define DADDR_TO_CHIPNO(daddr)	((daddr) / (HD_ROW2_ADDR * 2))
68 
69 static void	hlcd_cursor(void *, int, int, int);
70 static int	hlcd_mapchar(void *, int, unsigned int *);
71 static void	hlcd_putchar(void *, int, int, u_int, long);
72 static void	hlcd_copycols(void *, int, int, int,int);
73 static void	hlcd_erasecols(void *, int, int, int, long);
74 static void	hlcd_copyrows(void *, int, int, int);
75 static void	hlcd_eraserows(void *, int, int, long);
76 static int	hlcd_allocattr(void *, int, int, int, long *);
77 static void	hlcd_updatechar(struct hd44780_chip *, int, int);
78 static void	hlcd_redraw(void *);
79 
80 const struct wsdisplay_emulops hlcd_emulops = {
81 	hlcd_cursor,
82 	hlcd_mapchar,
83 	hlcd_putchar,
84 	hlcd_copycols,
85 	hlcd_erasecols,
86 	hlcd_copyrows,
87 	hlcd_eraserows,
88 	hlcd_allocattr
89 };
90 
91 static int	hlcd_ioctl(void *, void *, u_long, caddr_t, int, struct lwp *);
92 static paddr_t	hlcd_mmap(void *, void *, off_t, int);
93 static int	hlcd_alloc_screen(void *, const struct wsscreen_descr *,
94 		    void **, int *, int *, long *);
95 static void	hlcd_free_screen(void *, void *);
96 static int	hlcd_show_screen(void *, void *, int,
97 		    void (*) (void *, int, int), void *);
98 
99 const struct wsdisplay_accessops hlcd_accessops = {
100 	hlcd_ioctl,
101 	hlcd_mmap,
102 	hlcd_alloc_screen,
103 	hlcd_free_screen,
104 	hlcd_show_screen,
105 	0 /* load_font */
106 };
107 
108 static void
109 hlcd_cursor(id, on, row, col)
110 	void *id;
111 	int on, row, col;
112 {
113 	struct hlcd_screen *hdscr = id;
114 
115 	hdscr->hlcd_curon = on;
116 	hdscr->hlcd_curx = col;
117 	hdscr->hlcd_cury = row;
118 }
119 
120 static int
121 hlcd_mapchar(id, uni, index)
122 	void *id;
123 	int uni;
124 	unsigned int *index;
125 {
126 	if (uni < 256) {
127 		*index = uni;
128 		return (5);
129 	}
130 	*index = ' ';
131 	return (0);
132 }
133 
134 static void
135 hlcd_putchar(id, row, col, c, attr)
136 	void *id;
137 	int row, col;
138 	u_int c;
139 	long attr;
140 {
141 	struct hlcd_screen *hdscr = id;
142 
143 	c &= 0xff;
144 	if (row > 0 && (hdscr->hlcd_sc->sc_flags & (HD_MULTILINE|HD_MULTICHIP)))
145 		hdscr->image[hdscr->hlcd_sc->sc_cols * row + col] = c;
146 	else
147 		hdscr->image[col] = c;
148 }
149 
150 /*
151  * copies columns inside a row.
152  */
153 static void
154 hlcd_copycols(id, row, srccol, dstcol, ncols)
155 	void *id;
156 	int row, srccol, dstcol, ncols;
157 {
158 	struct hlcd_screen *hdscr = id;
159 
160 	if ((dstcol + ncols - 1) > hdscr->hlcd_sc->sc_cols)
161 		ncols = hdscr->hlcd_sc->sc_cols - srccol;
162 
163 	if (row > 0 && (hdscr->hlcd_sc->sc_flags & (HD_MULTILINE|HD_MULTICHIP)))
164 		bcopy(&hdscr->image[hdscr->hlcd_sc->sc_cols * row + srccol],
165 		    &hdscr->image[hdscr->hlcd_sc->sc_cols * row + dstcol], ncols);
166 	else
167 		bcopy(&hdscr->image[srccol], &hdscr->image[dstcol], ncols);
168 }
169 
170 
171 /*
172  * Erases a bunch of chars inside one row.
173  */
174 static void
175 hlcd_erasecols(id, row, startcol, ncols, fillattr)
176 	void *id;
177 	int row, startcol, ncols;
178 	long fillattr;
179 {
180 	struct hlcd_screen *hdscr = id;
181 
182 	if ((startcol + ncols) > hdscr->hlcd_sc->sc_cols)
183 		ncols = hdscr->hlcd_sc->sc_cols - startcol;
184 
185 	if (row > 0 && (hdscr->hlcd_sc->sc_flags & (HD_MULTILINE|HD_MULTICHIP)))
186 		memset(&hdscr->image[hdscr->hlcd_sc->sc_cols * row + startcol],
187 		    ' ', ncols);
188 	else
189 		memset(&hdscr->image[startcol], ' ', ncols);
190 }
191 
192 
193 static void
194 hlcd_copyrows(id, srcrow, dstrow, nrows)
195 	void *id;
196 	int srcrow, dstrow, nrows;
197 {
198 	struct hlcd_screen *hdscr = id;
199 	int ncols = hdscr->hlcd_sc->sc_cols;
200 
201 	if (!(hdscr->hlcd_sc->sc_flags & (HD_MULTILINE|HD_MULTICHIP)))
202 		return;
203 	bcopy(&hdscr->image[srcrow * ncols], &hdscr->image[dstrow * ncols],
204 	    nrows * ncols);
205 }
206 
207 static void
208 hlcd_eraserows(id, startrow, nrows, fillattr)
209 	void *id;
210 	int startrow, nrows;
211 	long fillattr;
212 {
213 	struct hlcd_screen *hdscr = id;
214 	int ncols = hdscr->hlcd_sc->sc_cols;
215 
216 	memset(&hdscr->image[startrow * ncols], ' ', ncols * nrows);
217 }
218 
219 
220 static int
221 hlcd_allocattr(id, fg, bg, flags, attrp)
222 	void *id;
223 	int fg, bg, flags;
224 	long *attrp;
225 {
226         *attrp = flags;
227         return 0;
228 }
229 
230 static int
231 hlcd_ioctl(v, vs, cmd, data, flag, l)
232 	void *v;
233 	void *vs;
234 	u_long cmd;
235 	caddr_t data;
236 	int flag;
237 	struct lwp *l;
238 {
239 
240 	switch (cmd) {
241 	case WSDISPLAYIO_GTYPE:
242 		*(u_int *)data = WSDISPLAY_TYPE_HDLCD;
243 		break;
244 
245 	case WSDISPLAYIO_SVIDEO:
246 		break;
247 
248 	case WSDISPLAYIO_GVIDEO:
249 		*(u_int *)data = WSDISPLAYIO_VIDEO_ON;
250 		break;
251 
252 	default:
253 		return EPASSTHROUGH;
254 	}
255 	return 0;
256 }
257 
258 static paddr_t
259 hlcd_mmap(v, vs, offset, prot)
260 	void *v;
261 	void *vs;
262 	off_t offset;
263 	int prot;
264 {
265 	return -1;
266 }
267 
268 static int
269 hlcd_alloc_screen(v, type, cookiep, curxp, curyp, defattrp)
270 	void *v;
271 	const struct wsscreen_descr *type;
272 	void **cookiep;
273 	int *curxp, *curyp;
274 	long *defattrp;
275 {
276 	struct hlcd_screen *hdscr = v, *new;
277 
278 	new = *cookiep = malloc(sizeof(struct hlcd_screen), M_DEVBUF, M_WAITOK);
279 	bzero(*cookiep, sizeof(struct hlcd_screen));
280 	new->hlcd_sc = hdscr->hlcd_sc;
281 	new->image = malloc(PAGE_SIZE, M_DEVBUF, M_WAITOK);
282 	memset(new->image, ' ', PAGE_SIZE);
283 	*curxp = *curyp = *defattrp = 0;
284 	return 0;
285 }
286 
287 static void
288 hlcd_free_screen(v, cookie)
289 	void *v, *cookie;
290 {
291 }
292 
293 static int
294 hlcd_show_screen(v, cookie, waitok, cb, cbarg)
295 	void *v, *cookie, *cbarg;
296 	int waitok;
297 	void (*cb)(void *, int, int);
298 {
299 	struct hlcd_screen *hdscr = v;
300 
301 	hdscr->hlcd_sc->sc_curscr = cookie;
302 	callout_schedule(&hdscr->hlcd_sc->redraw, 1);
303 	return (0);
304 }
305 
306 static void
307 hlcd_updatechar(sc, daddr, c)
308 	struct hd44780_chip *sc;
309 	int daddr, c;
310 {
311 	int curdaddr, en, chipdaddr;
312 
313 	curdaddr = COORD_TO_DADDR(sc->sc_screen.hlcd_curx,
314 	    sc->sc_screen.hlcd_cury);
315 	en = DADDR_TO_CHIPNO(daddr);
316 	chipdaddr = DADDR_TO_CHIPDADDR(daddr);
317 	if (daddr != curdaddr)
318 		hd44780_ir_write(sc, en, cmd_ddramset(chipdaddr));
319 
320 	hd44780_dr_write(sc, en, c);
321 
322 	daddr++;
323 	sc->sc_screen.hlcd_curx = DADDR_TO_COL(daddr);
324 	sc->sc_screen.hlcd_cury = DADDR_TO_ROW(daddr);
325 }
326 
327 static void
328 hlcd_redraw(arg)
329 	void *arg;
330 {
331 	struct hd44780_chip *sc = arg;
332 	int len, crsridx, startidx, x, y;
333 	int old_en, new_en;
334 	u_char *img, *curimg;
335 
336 	if (sc->sc_curscr == NULL)
337 		return;
338 
339 	if (sc->sc_flags & HD_MULTILINE)
340 		len = 2 * sc->sc_cols;
341 	else
342 		len = sc->sc_cols;
343 
344 	if (sc->sc_flags & HD_MULTICHIP)
345 		len = len * 2;
346 
347 	x = sc->sc_screen.hlcd_curx;
348 	y = sc->sc_screen.hlcd_cury;
349 	old_en = DADDR_TO_CHIPNO(COORD_TO_DADDR(x, y));
350 
351 	img = sc->sc_screen.image;
352 	curimg = sc->sc_curscr->image;
353 	startidx = crsridx =
354 	    COORD_TO_IDX(sc->sc_screen.hlcd_curx, sc->sc_screen.hlcd_cury);
355 	do {
356 		if (img[crsridx] != curimg[crsridx]) {
357 			hlcd_updatechar(sc, IDX_TO_DADDR(crsridx),
358 			    curimg[crsridx]);
359 			img[crsridx] = curimg[crsridx];
360 		}
361 		crsridx++;
362 		if (crsridx == len)
363 			crsridx = 0;
364 	} while (crsridx != startidx);
365 
366 	x = sc->sc_curscr->hlcd_curx;
367 	y = sc->sc_curscr->hlcd_cury;
368 	new_en = DADDR_TO_CHIPNO(COORD_TO_DADDR(x, y));
369 
370 	if (sc->sc_screen.hlcd_curx != sc->sc_curscr->hlcd_curx ||
371 	    sc->sc_screen.hlcd_cury != sc->sc_curscr->hlcd_cury) {
372 
373 		x = sc->sc_screen.hlcd_curx = sc->sc_curscr->hlcd_curx;
374 		y = sc->sc_screen.hlcd_cury = sc->sc_curscr->hlcd_cury;
375 
376 		hd44780_ir_write(sc, new_en, cmd_ddramset(
377 		    DADDR_TO_CHIPDADDR(COORD_TO_DADDR(x, y))));
378 
379 	}
380 
381 	/* visible cursor switched to other chip */
382 	if (old_en != new_en && sc->sc_screen.hlcd_curon) {
383 		hd44780_ir_write(sc, old_en, cmd_dispctl(1, 0, 0));
384 		hd44780_ir_write(sc, new_en, cmd_dispctl(1, 1, 1));
385 	}
386 
387 	if (sc->sc_screen.hlcd_curon != sc->sc_curscr->hlcd_curon) {
388 		sc->sc_screen.hlcd_curon = sc->sc_curscr->hlcd_curon;
389 		if (sc->sc_screen.hlcd_curon)
390 			hd44780_ir_write(sc, new_en, cmd_dispctl(1, 1, 1));
391 		else
392 			hd44780_ir_write(sc, new_en, cmd_dispctl(1, 0, 0));
393 	}
394 
395 	callout_schedule(&sc->redraw, 1);
396 }
397 
398 
399 /*
400  * Finish device attach. sc_writereg, sc_readreg and sc_flags must be properly
401  * initialized prior to this call.
402  */
403 void
404 hd44780_attach_subr(sc)
405 	struct hd44780_chip *sc;
406 {
407 	int err = 0;
408 	/* Putc/getc are supposed to be set by platform-dependent code. */
409 	if ((sc->sc_writereg == NULL) || (sc->sc_readreg == NULL))
410 		sc->sc_dev_ok = 0;
411 
412 	/* Make sure that HD_MAX_CHARS is enough. */
413 	if ((sc->sc_flags & HD_MULTILINE) && (2 * sc->sc_cols > HD_MAX_CHARS))
414 		sc->sc_dev_ok = 0;
415 	else if (sc->sc_cols > HD_MAX_CHARS)
416 		sc->sc_dev_ok = 0;
417 
418 	if (sc->sc_dev_ok) {
419 		if ((sc->sc_flags & HD_UP) == 0)
420 			err = hd44780_init(sc);
421 		if (err != 0)
422 			printf("%s: LCD not responding or unconnected\n", sc->sc_dev->dv_xname);
423 
424 	}
425 
426 	sc->sc_screen.hlcd_sc = sc;
427 
428 	sc->sc_screen.image = malloc(PAGE_SIZE, M_DEVBUF, M_WAITOK);
429 	memset(sc->sc_screen.image, ' ', PAGE_SIZE);
430 	sc->sc_curscr = NULL;
431 	sc->sc_curchip = 0;
432 	callout_init(&sc->redraw);
433 	callout_setfunc(&sc->redraw, hlcd_redraw, sc);
434 }
435 
436 int hd44780_init(sc)
437 	struct hd44780_chip *sc;
438 {
439 	int ret;
440 
441 	ret = hd44780_chipinit(sc, 0);
442 	if (ret != 0 || !(sc->sc_flags & HD_MULTICHIP)) return ret;
443 	else return hd44780_chipinit(sc, 1);
444 }
445 
446 /*
447  * Initialize 4-bit or 8-bit connected device.
448  */
449 int
450 hd44780_chipinit(sc, en)
451 	struct hd44780_chip *sc;
452 	u_int32_t en;
453 {
454 	u_int8_t cmd, dat;
455 
456 	sc->sc_flags &= ~(HD_TIMEDOUT|HD_UP);
457 	sc->sc_dev_ok = 1;
458 
459 	cmd = cmd_init(sc->sc_flags & HD_8BIT);
460 	hd44780_ir_write(sc, en, cmd);
461 	delay(HD_TIMEOUT_LONG);
462 	hd44780_ir_write(sc, en, cmd);
463 	hd44780_ir_write(sc, en, cmd);
464 
465 	cmd = cmd_funcset(
466 			sc->sc_flags & HD_8BIT,
467 			sc->sc_flags & HD_MULTILINE,
468 			sc->sc_flags & HD_BIGFONT);
469 
470 	if ((sc->sc_flags & HD_8BIT) == 0)
471 		hd44780_ir_write(sc, en, cmd);
472 
473 	sc->sc_flags |= HD_UP;
474 
475 	hd44780_ir_write(sc, en, cmd);
476 	hd44780_ir_write(sc, en, cmd_dispctl(0, 0, 0));
477 	hd44780_ir_write(sc, en, cmd_clear());
478 	hd44780_ir_write(sc, en, cmd_modset(1, 0));
479 
480 	if (sc->sc_flags & HD_TIMEDOUT) {
481 		sc->sc_flags &= ~HD_UP;
482 		return EIO;
483 	}
484 
485 	/* Turn display on and clear it. */
486 	hd44780_ir_write(sc, en, cmd_clear());
487 	hd44780_ir_write(sc, en, cmd_dispctl(1, 0, 0));
488 
489 	/* Attempt a simple probe for presence */
490 	hd44780_ir_write(sc, en, cmd_ddramset(0x5));
491 	hd44780_ir_write(sc, en, cmd_shift(0, 1));
492 	hd44780_busy_wait(sc, en);
493 	if ((dat = hd44780_ir_read(sc, en) & 0x7f) != 0x6) {
494 		sc->sc_dev_ok = 0;
495 		sc->sc_flags &= ~HD_UP;
496 		return EIO;
497 	}
498 	hd44780_ir_write(sc, en, cmd_ddramset(0));
499 
500 	return 0;
501 }
502 
503 /*
504  * Standard hd44780 ioctl() functions.
505  */
506 int
507 hd44780_ioctl_subr(sc, cmd, data)
508 	struct hd44780_chip *sc;
509 	u_long cmd;
510 	caddr_t data;
511 {
512 	u_int8_t tmp;
513 	int error = 0;
514 	u_int32_t en = sc->sc_curchip;
515 
516 #define hd44780_io()	((struct hd44780_io *)data)
517 #define hd44780_info()	((struct hd44780_info*)data)
518 #define hd44780_ctrl()	((struct hd44780_dispctl*)data)
519 
520 	switch (cmd) {
521 		/* Clear the LCD. */
522 		case HLCD_CLEAR:
523 			hd44780_ir_write(sc, en, cmd_clear());
524 			break;
525 
526 		/* Move the cursor one position to the left. */
527 		case HLCD_CURSOR_LEFT:
528 			hd44780_ir_write(sc, en, cmd_shift(0, 0));
529 			break;
530 
531 		/* Move the cursor one position to the right. */
532 		case HLCD_CURSOR_RIGHT:
533 			hd44780_ir_write(sc, en, cmd_shift(0, 1));
534 			break;
535 
536 		/* Control the LCD. */
537 		case HLCD_DISPCTL:
538 			hd44780_ir_write(sc, en, cmd_dispctl(
539 						hd44780_ctrl()->display_on,
540 						hd44780_ctrl()->cursor_on,
541 						hd44780_ctrl()->blink_on));
542 			break;
543 
544 		/* Get LCD configuration. */
545 		case HLCD_GET_INFO:
546 			hd44780_info()->lines
547 				= (sc->sc_flags & HD_MULTILINE) ? 2 : 1;
548 			if (sc->sc_flags & HD_MULTICHIP)
549 				hd44780_info()->lines *= 2;
550 			hd44780_info()->phys_rows = sc->sc_cols;
551 			hd44780_info()->virt_rows = sc->sc_vcols;
552 			hd44780_info()->is_wide = sc->sc_flags & HD_8BIT;
553 			hd44780_info()->is_bigfont = sc->sc_flags & HD_BIGFONT;
554 			hd44780_info()->kp_present = sc->sc_flags & HD_KEYPAD;
555 			break;
556 
557 
558 		/* Reset the LCD. */
559 		case HLCD_RESET:
560 			error = hd44780_init(sc);
561 			break;
562 
563 		/* Get the current cursor position. */
564 		case HLCD_GET_CURSOR_POS:
565 			hd44780_io()->dat = (hd44780_ir_read(sc, en) & 0x7f);
566 			break;
567 
568 		/* Set the cursor position. */
569 		case HLCD_SET_CURSOR_POS:
570 			hd44780_ir_write(sc, en, cmd_ddramset(hd44780_io()->dat));
571 			break;
572 
573 		/* Get the value at the current cursor position. */
574 		case HLCD_GETC:
575 			tmp = (hd44780_ir_read(sc, en) & 0x7f);
576 			hd44780_ir_write(sc, en, cmd_ddramset(tmp));
577 			hd44780_io()->dat = hd44780_dr_read(sc, en);
578 			break;
579 
580 		/* Set the character at the cursor position + advance cursor. */
581 		case HLCD_PUTC:
582 			hd44780_dr_write(sc, en, hd44780_io()->dat);
583 			break;
584 
585 		/* Shift display left. */
586 		case HLCD_SHIFT_LEFT:
587 			hd44780_ir_write(sc, en, cmd_shift(1, 0));
588 			break;
589 
590 		/* Shift display right. */
591 		case HLCD_SHIFT_RIGHT:
592 			hd44780_ir_write(sc, en, cmd_shift(1, 1));
593 			break;
594 
595 		/* Return home. */
596 		case HLCD_HOME:
597 			hd44780_ir_write(sc, en, cmd_rethome());
598 			break;
599 
600 		/* Write a string to the LCD virtual area. */
601 		case HLCD_WRITE:
602 			error = hd44780_ddram_io(sc, en, hd44780_io(), HD_DDRAM_WRITE);
603 			break;
604 
605 		/* Read LCD virtual area. */
606 		case HLCD_READ:
607 			error = hd44780_ddram_io(sc, en, hd44780_io(), HD_DDRAM_READ);
608 			break;
609 
610 		/* Write to the LCD visible area. */
611 		case HLCD_REDRAW:
612 			hd44780_ddram_redraw(sc, en, hd44780_io());
613 			break;
614 
615 		/* Write raw instruction. */
616 		case HLCD_WRITE_INST:
617 			hd44780_ir_write(sc, en, hd44780_io()->dat);
618 			break;
619 
620 		/* Write raw data. */
621 		case HLCD_WRITE_DATA:
622 			hd44780_dr_write(sc, en, hd44780_io()->dat);
623 			break;
624 
625 		/* Get current chip 0 or 1 (top or bottom) */
626 		case HLCD_GET_CHIPNO:
627 			*(u_int8_t *)data = sc->sc_curchip;
628 			break;
629 
630 		/* Set current chip 0 or 1 (top or bottom) */
631 		case HLCD_SET_CHIPNO:
632 			sc->sc_curchip = *(u_int8_t *)data;
633 			break;
634 
635 		default:
636 			error = EINVAL;
637 	}
638 
639 	if (sc->sc_flags & HD_TIMEDOUT)
640 		error = EIO;
641 
642 	return error;
643 }
644 
645 /*
646  * Read/write particular area of the LCD screen.
647  */
648 int
649 hd44780_ddram_io(sc, en, io, dir)
650 	struct hd44780_chip *sc;
651 	u_int32_t en;
652 	struct hd44780_io *io;
653 	u_char dir;
654 {
655 	u_int8_t hi;
656 	u_int8_t addr;
657 
658 	int error = 0;
659 	u_int8_t i = 0;
660 
661 	if (io->dat < sc->sc_vcols) {
662 		hi = HD_ROW1_ADDR + sc->sc_vcols;
663 		addr = HD_ROW1_ADDR + io->dat;
664 		for (; (addr < hi) && (i < io->len); addr++, i++) {
665 			hd44780_ir_write(sc, en, cmd_ddramset(addr));
666 			if (dir == HD_DDRAM_READ)
667 				io->buf[i] = hd44780_dr_read(sc, en);
668 			else
669 				hd44780_dr_write(sc, en, io->buf[i]);
670 		}
671 	}
672 	if (io->dat < 2 * sc->sc_vcols) {
673 		hi = HD_ROW2_ADDR + sc->sc_vcols;
674 		if (io->dat >= sc->sc_vcols)
675 			addr = HD_ROW2_ADDR + io->dat - sc->sc_vcols;
676 		else
677 			addr = HD_ROW2_ADDR;
678 		for (; (addr < hi) && (i < io->len); addr++, i++) {
679 			hd44780_ir_write(sc, en, cmd_ddramset(addr));
680 			if (dir == HD_DDRAM_READ)
681 				io->buf[i] = hd44780_dr_read(sc, en);
682 			else
683 				hd44780_dr_write(sc, en, io->buf[i]);
684 		}
685 		if (i < io->len)
686 			io->len = i;
687 	} else {
688 		error = EINVAL;
689 	}
690 	return error;
691 }
692 
693 /*
694  * Write to the visible area of the display.
695  */
696 void
697 hd44780_ddram_redraw(sc, en, io)
698 	struct hd44780_chip *sc;
699 	u_int32_t en;
700 	struct hd44780_io *io;
701 {
702 	u_int8_t i;
703 
704 	hd44780_ir_write(sc, en, cmd_clear());
705 	hd44780_ir_write(sc, en, cmd_rethome());
706 	for (i = 0; (i < io->len) && (i < sc->sc_cols); i++) {
707 		hd44780_dr_write(sc, en, io->buf[i]);
708 	}
709 	hd44780_ir_write(sc, en, cmd_ddramset(HD_ROW2_ADDR));
710 	for (; (i < io->len); i++)
711 		hd44780_dr_write(sc, en, io->buf[i]);
712 }
713 
714 void
715 hd44780_busy_wait(sc, en)
716 	struct hd44780_chip *sc;
717 	u_int32_t en;
718 {
719 	int nloops = 100;
720 
721 	if (sc->sc_flags & HD_TIMEDOUT)
722 		return;
723 
724 	while(nloops-- && (hd44780_ir_read(sc, en) & BUSY_FLAG) == BUSY_FLAG);
725 
726 	if (nloops == 0) {
727 		sc->sc_flags |= HD_TIMEDOUT;
728 		sc->sc_dev_ok = 0;
729 	}
730 }
731 
732 #if defined(HD44780_STD_WIDE)
733 /*
734  * Standard 8-bit version of 'sc_writereg' (8-bit port, 8-bit access)
735  */
736 void
737 hd44780_writereg(sc, en, reg, cmd)
738 	struct hd44780_chip *sc;
739 	u_int32_t en, reg;
740 	u_int8_t cmd;
741 {
742 	bus_space_tag_t iot = sc->sc_iot;
743 	bus_space_handle_t ioh;
744 
745 	if (sc->sc_dev_ok == 0)
746 		return;
747 
748 	if (reg == 0)
749 		ioh = sc->sc_ioir;
750 	else
751 		ioh = sc->sc_iodr;
752 
753 	bus_space_write_1(iot, ioh, 0x00, cmd);
754 	delay(HD_TIMEOUT_NORMAL);
755 }
756 
757 /*
758  * Standard 8-bit version of 'sc_readreg' (8-bit port, 8-bit access)
759  */
760 u_int8_t
761 hd44780_readreg(sc, en, reg)
762 	struct hd44780_chip *sc;
763 	u_int32_t en, reg;
764 {
765 	bus_space_tag_t iot = sc->sc_iot;
766 	bus_space_handle_t ioh;
767 
768 	if (sc->sc_dev_ok == 0)
769 		return;
770 
771 	if (reg == 0)
772 		ioh = sc->sc_ioir;
773 	else
774 		ioh = sc->sc_iodr;
775 
776 	delay(HD_TIMEOUT_NORMAL);
777 	return bus_space_read_1(iot, ioh, 0x00);
778 }
779 #elif defined(HD44780_STD_SHORT)
780 /*
781  * Standard 4-bit version of 'sc_writereg' (4-bit port, 8-bit access)
782  */
783 void
784 hd44780_writereg(sc, en, reg, cmd)
785 	struct hd44780_chip *sc;
786 	u_int32_t en, reg;
787 	u_int8_t cmd;
788 {
789 	bus_space_tag_t iot = sc->sc_iot;
790 	bus_space_handle_t ioh;
791 
792 	if (sc->sc_dev_ok == 0)
793 		return;
794 
795 	if (reg == 0)
796 		ioh = sc->sc_ioir;
797 	else
798 		ioh = sc->sc_iodr;
799 
800 	bus_space_write_1(iot, ioh, 0x00, hi_bits(cmd));
801 	if (sc->sc_flags & HD_UP)
802 		bus_space_write_1(iot, ioh, 0x00, lo_bits(cmd));
803 	delay(HD_TIMEOUT_NORMAL);
804 }
805 
806 /*
807  * Standard 4-bit version of 'sc_readreg' (4-bit port, 8-bit access)
808  */
809 u_int8_t
810 hd44780_readreg(sc, en, reg)
811 	struct hd44780_chip *sc;
812 	u_int32_t en, reg;
813 {
814 	bus_space_tag_t iot = sc->sc_iot;
815 	bus_space_handle_t ioh;
816 	u_int8_t rd, dat;
817 
818 	if (sc->sc_dev_ok == 0)
819 		return;
820 
821 	if (reg == 0)
822 		ioh = sc->sc_ioir;
823 	else
824 		ioh = sc->sc_iodr;
825 
826 	rd = bus_space_read_1(iot, ioh, 0x00);
827 	dat = (rd & 0x0f) << 4;
828 	rd = bus_space_read_1(iot, ioh, 0x00);
829 	return (dat | (rd & 0x0f));
830 }
831 #endif
832