xref: /netbsd-src/sys/dev/ic/hd44780_subr.c (revision 8b0f9554ff8762542c4defc4f70e1eb76fb508fa)
1 /* $NetBSD: hd44780_subr.c,v 1.13 2007/11/01 13:05:32 tsutsui 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 1.13 2007/11/01 13:05:32 tsutsui 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 <sys/intr.h>
47 #include <sys/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, void *, 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 		memmove(&hdscr->image[hdscr->hlcd_sc->sc_cols * row + dstcol],
165 		    &hdscr->image[hdscr->hlcd_sc->sc_cols * row + srccol],
166 		    ncols);
167 	else
168 		memmove(&hdscr->image[dstcol], &hdscr->image[srccol], ncols);
169 }
170 
171 
172 /*
173  * Erases a bunch of chars inside one row.
174  */
175 static void
176 hlcd_erasecols(id, row, startcol, ncols, fillattr)
177 	void *id;
178 	int row, startcol, ncols;
179 	long fillattr;
180 {
181 	struct hlcd_screen *hdscr = id;
182 
183 	if ((startcol + ncols) > hdscr->hlcd_sc->sc_cols)
184 		ncols = hdscr->hlcd_sc->sc_cols - startcol;
185 
186 	if (row > 0 && (hdscr->hlcd_sc->sc_flags & (HD_MULTILINE|HD_MULTICHIP)))
187 		memset(&hdscr->image[hdscr->hlcd_sc->sc_cols * row + startcol],
188 		    ' ', ncols);
189 	else
190 		memset(&hdscr->image[startcol], ' ', ncols);
191 }
192 
193 
194 static void
195 hlcd_copyrows(id, srcrow, dstrow, nrows)
196 	void *id;
197 	int srcrow, dstrow, nrows;
198 {
199 	struct hlcd_screen *hdscr = id;
200 	int ncols = hdscr->hlcd_sc->sc_cols;
201 
202 	if (!(hdscr->hlcd_sc->sc_flags & (HD_MULTILINE|HD_MULTICHIP)))
203 		return;
204 	memmove(&hdscr->image[dstrow * ncols], &hdscr->image[srcrow * ncols],
205 	    nrows * ncols);
206 }
207 
208 static void
209 hlcd_eraserows(id, startrow, nrows, fillattr)
210 	void *id;
211 	int startrow, nrows;
212 	long fillattr;
213 {
214 	struct hlcd_screen *hdscr = id;
215 	int ncols = hdscr->hlcd_sc->sc_cols;
216 
217 	memset(&hdscr->image[startrow * ncols], ' ', ncols * nrows);
218 }
219 
220 
221 static int
222 hlcd_allocattr(id, fg, bg, flags, attrp)
223 	void *id;
224 	int fg, bg, flags;
225 	long *attrp;
226 {
227         *attrp = flags;
228         return 0;
229 }
230 
231 static int
232 hlcd_ioctl(v, vs, cmd, data, flag, l)
233 	void *v;
234 	void *vs;
235 	u_long cmd;
236 	void *data;
237 	int flag;
238 	struct lwp *l;
239 {
240 
241 	switch (cmd) {
242 	case WSDISPLAYIO_GTYPE:
243 		*(u_int *)data = WSDISPLAY_TYPE_HDLCD;
244 		break;
245 
246 	case WSDISPLAYIO_SVIDEO:
247 		break;
248 
249 	case WSDISPLAYIO_GVIDEO:
250 		*(u_int *)data = WSDISPLAYIO_VIDEO_ON;
251 		break;
252 
253 	default:
254 		return EPASSTHROUGH;
255 	}
256 	return 0;
257 }
258 
259 static paddr_t
260 hlcd_mmap(v, vs, offset, prot)
261 	void *v;
262 	void *vs;
263 	off_t offset;
264 	int prot;
265 {
266 	return -1;
267 }
268 
269 static int
270 hlcd_alloc_screen(v, type, cookiep, curxp, curyp, defattrp)
271 	void *v;
272 	const struct wsscreen_descr *type;
273 	void **cookiep;
274 	int *curxp, *curyp;
275 	long *defattrp;
276 {
277 	struct hlcd_screen *hdscr = v, *new;
278 
279 	new = *cookiep = malloc(sizeof(struct hlcd_screen), M_DEVBUF, M_WAITOK);
280 	bzero(*cookiep, sizeof(struct hlcd_screen));
281 	new->hlcd_sc = hdscr->hlcd_sc;
282 	new->image = malloc(PAGE_SIZE, M_DEVBUF, M_WAITOK);
283 	memset(new->image, ' ', PAGE_SIZE);
284 	*curxp = *curyp = *defattrp = 0;
285 	return 0;
286 }
287 
288 static void
289 hlcd_free_screen(v, cookie)
290 	void *v, *cookie;
291 {
292 }
293 
294 static int
295 hlcd_show_screen(v, cookie, waitok, cb, cbarg)
296 	void *v, *cookie, *cbarg;
297 	int waitok;
298 	void (*cb)(void *, int, int);
299 {
300 	struct hlcd_screen *hdscr = v;
301 
302 	hdscr->hlcd_sc->sc_curscr = cookie;
303 	callout_schedule(&hdscr->hlcd_sc->redraw, 1);
304 	return (0);
305 }
306 
307 static void
308 hlcd_updatechar(sc, daddr, c)
309 	struct hd44780_chip *sc;
310 	int daddr, c;
311 {
312 	int curdaddr, en, chipdaddr;
313 
314 	curdaddr = COORD_TO_DADDR(sc->sc_screen.hlcd_curx,
315 	    sc->sc_screen.hlcd_cury);
316 	en = DADDR_TO_CHIPNO(daddr);
317 	chipdaddr = DADDR_TO_CHIPDADDR(daddr);
318 	if (daddr != curdaddr)
319 		hd44780_ir_write(sc, en, cmd_ddramset(chipdaddr));
320 
321 	hd44780_dr_write(sc, en, c);
322 
323 	daddr++;
324 	sc->sc_screen.hlcd_curx = DADDR_TO_COL(daddr);
325 	sc->sc_screen.hlcd_cury = DADDR_TO_ROW(daddr);
326 }
327 
328 static void
329 hlcd_redraw(arg)
330 	void *arg;
331 {
332 	struct hd44780_chip *sc = arg;
333 	int len, crsridx, startidx, x, y;
334 	int old_en, new_en;
335 	u_char *img, *curimg;
336 
337 	if (sc->sc_curscr == NULL)
338 		return;
339 
340 	if (sc->sc_flags & HD_MULTILINE)
341 		len = 2 * sc->sc_cols;
342 	else
343 		len = sc->sc_cols;
344 
345 	if (sc->sc_flags & HD_MULTICHIP)
346 		len = len * 2;
347 
348 	x = sc->sc_screen.hlcd_curx;
349 	y = sc->sc_screen.hlcd_cury;
350 	old_en = DADDR_TO_CHIPNO(COORD_TO_DADDR(x, y));
351 
352 	img = sc->sc_screen.image;
353 	curimg = sc->sc_curscr->image;
354 	startidx = crsridx =
355 	    COORD_TO_IDX(sc->sc_screen.hlcd_curx, sc->sc_screen.hlcd_cury);
356 	do {
357 		if (img[crsridx] != curimg[crsridx]) {
358 			hlcd_updatechar(sc, IDX_TO_DADDR(crsridx),
359 			    curimg[crsridx]);
360 			img[crsridx] = curimg[crsridx];
361 		}
362 		crsridx++;
363 		if (crsridx == len)
364 			crsridx = 0;
365 	} while (crsridx != startidx);
366 
367 	x = sc->sc_curscr->hlcd_curx;
368 	y = sc->sc_curscr->hlcd_cury;
369 	new_en = DADDR_TO_CHIPNO(COORD_TO_DADDR(x, y));
370 
371 	if (sc->sc_screen.hlcd_curx != sc->sc_curscr->hlcd_curx ||
372 	    sc->sc_screen.hlcd_cury != sc->sc_curscr->hlcd_cury) {
373 
374 		x = sc->sc_screen.hlcd_curx = sc->sc_curscr->hlcd_curx;
375 		y = sc->sc_screen.hlcd_cury = sc->sc_curscr->hlcd_cury;
376 
377 		hd44780_ir_write(sc, new_en, cmd_ddramset(
378 		    DADDR_TO_CHIPDADDR(COORD_TO_DADDR(x, y))));
379 
380 	}
381 
382 	/* visible cursor switched to other chip */
383 	if (old_en != new_en && sc->sc_screen.hlcd_curon) {
384 		hd44780_ir_write(sc, old_en, cmd_dispctl(1, 0, 0));
385 		hd44780_ir_write(sc, new_en, cmd_dispctl(1, 1, 1));
386 	}
387 
388 	if (sc->sc_screen.hlcd_curon != sc->sc_curscr->hlcd_curon) {
389 		sc->sc_screen.hlcd_curon = sc->sc_curscr->hlcd_curon;
390 		if (sc->sc_screen.hlcd_curon)
391 			hd44780_ir_write(sc, new_en, cmd_dispctl(1, 1, 1));
392 		else
393 			hd44780_ir_write(sc, new_en, cmd_dispctl(1, 0, 0));
394 	}
395 
396 	callout_schedule(&sc->redraw, 1);
397 }
398 
399 
400 /*
401  * Finish device attach. sc_writereg, sc_readreg and sc_flags must be properly
402  * initialized prior to this call.
403  */
404 void
405 hd44780_attach_subr(sc)
406 	struct hd44780_chip *sc;
407 {
408 	int err = 0;
409 	/* Putc/getc are supposed to be set by platform-dependent code. */
410 	if ((sc->sc_writereg == NULL) || (sc->sc_readreg == NULL))
411 		sc->sc_dev_ok = 0;
412 
413 	/* Make sure that HD_MAX_CHARS is enough. */
414 	if ((sc->sc_flags & HD_MULTILINE) && (2 * sc->sc_cols > HD_MAX_CHARS))
415 		sc->sc_dev_ok = 0;
416 	else if (sc->sc_cols > HD_MAX_CHARS)
417 		sc->sc_dev_ok = 0;
418 
419 	if (sc->sc_dev_ok) {
420 		if ((sc->sc_flags & HD_UP) == 0)
421 			err = hd44780_init(sc);
422 		if (err != 0)
423 			printf("%s: LCD not responding or unconnected\n", sc->sc_dev->dv_xname);
424 
425 	}
426 
427 	sc->sc_screen.hlcd_sc = sc;
428 
429 	sc->sc_screen.image = malloc(PAGE_SIZE, M_DEVBUF, M_WAITOK);
430 	memset(sc->sc_screen.image, ' ', PAGE_SIZE);
431 	sc->sc_curscr = NULL;
432 	sc->sc_curchip = 0;
433 	callout_init(&sc->redraw, 0);
434 	callout_setfunc(&sc->redraw, hlcd_redraw, sc);
435 }
436 
437 int hd44780_init(sc)
438 	struct hd44780_chip *sc;
439 {
440 	int ret;
441 
442 	ret = hd44780_chipinit(sc, 0);
443 	if (ret != 0 || !(sc->sc_flags & HD_MULTICHIP)) return ret;
444 	else return hd44780_chipinit(sc, 1);
445 }
446 
447 /*
448  * Initialize 4-bit or 8-bit connected device.
449  */
450 int
451 hd44780_chipinit(sc, en)
452 	struct hd44780_chip *sc;
453 	u_int32_t en;
454 {
455 	u_int8_t cmd, dat;
456 
457 	sc->sc_flags &= ~(HD_TIMEDOUT|HD_UP);
458 	sc->sc_dev_ok = 1;
459 
460 	cmd = cmd_init(sc->sc_flags & HD_8BIT);
461 	hd44780_ir_write(sc, en, cmd);
462 	delay(HD_TIMEOUT_LONG);
463 	hd44780_ir_write(sc, en, cmd);
464 	hd44780_ir_write(sc, en, cmd);
465 
466 	cmd = cmd_funcset(
467 			sc->sc_flags & HD_8BIT,
468 			sc->sc_flags & HD_MULTILINE,
469 			sc->sc_flags & HD_BIGFONT);
470 
471 	if ((sc->sc_flags & HD_8BIT) == 0)
472 		hd44780_ir_write(sc, en, cmd);
473 
474 	sc->sc_flags |= HD_UP;
475 
476 	hd44780_ir_write(sc, en, cmd);
477 	hd44780_ir_write(sc, en, cmd_dispctl(0, 0, 0));
478 	hd44780_ir_write(sc, en, cmd_clear());
479 	hd44780_ir_write(sc, en, cmd_modset(1, 0));
480 
481 	if (sc->sc_flags & HD_TIMEDOUT) {
482 		sc->sc_flags &= ~HD_UP;
483 		return EIO;
484 	}
485 
486 	/* Turn display on and clear it. */
487 	hd44780_ir_write(sc, en, cmd_clear());
488 	hd44780_ir_write(sc, en, cmd_dispctl(1, 0, 0));
489 
490 	/* Attempt a simple probe for presence */
491 	hd44780_ir_write(sc, en, cmd_ddramset(0x5));
492 	hd44780_ir_write(sc, en, cmd_shift(0, 1));
493 	hd44780_busy_wait(sc, en);
494 	if ((dat = hd44780_ir_read(sc, en) & 0x7f) != 0x6) {
495 		sc->sc_dev_ok = 0;
496 		sc->sc_flags &= ~HD_UP;
497 		return EIO;
498 	}
499 	hd44780_ir_write(sc, en, cmd_ddramset(0));
500 
501 	return 0;
502 }
503 
504 /*
505  * Standard hd44780 ioctl() functions.
506  */
507 int
508 hd44780_ioctl_subr(sc, cmd, data)
509 	struct hd44780_chip *sc;
510 	u_long cmd;
511 	void *data;
512 {
513 	u_int8_t tmp;
514 	int error = 0;
515 	u_int32_t en = sc->sc_curchip;
516 
517 #define hd44780_io()	((struct hd44780_io *)data)
518 #define hd44780_info()	((struct hd44780_info*)data)
519 #define hd44780_ctrl()	((struct hd44780_dispctl*)data)
520 
521 	switch (cmd) {
522 		/* Clear the LCD. */
523 		case HLCD_CLEAR:
524 			hd44780_ir_write(sc, en, cmd_clear());
525 			break;
526 
527 		/* Move the cursor one position to the left. */
528 		case HLCD_CURSOR_LEFT:
529 			hd44780_ir_write(sc, en, cmd_shift(0, 0));
530 			break;
531 
532 		/* Move the cursor one position to the right. */
533 		case HLCD_CURSOR_RIGHT:
534 			hd44780_ir_write(sc, en, cmd_shift(0, 1));
535 			break;
536 
537 		/* Control the LCD. */
538 		case HLCD_DISPCTL:
539 			hd44780_ir_write(sc, en, cmd_dispctl(
540 						hd44780_ctrl()->display_on,
541 						hd44780_ctrl()->cursor_on,
542 						hd44780_ctrl()->blink_on));
543 			break;
544 
545 		/* Get LCD configuration. */
546 		case HLCD_GET_INFO:
547 			hd44780_info()->lines
548 				= (sc->sc_flags & HD_MULTILINE) ? 2 : 1;
549 			if (sc->sc_flags & HD_MULTICHIP)
550 				hd44780_info()->lines *= 2;
551 			hd44780_info()->phys_rows = sc->sc_cols;
552 			hd44780_info()->virt_rows = sc->sc_vcols;
553 			hd44780_info()->is_wide = sc->sc_flags & HD_8BIT;
554 			hd44780_info()->is_bigfont = sc->sc_flags & HD_BIGFONT;
555 			hd44780_info()->kp_present = sc->sc_flags & HD_KEYPAD;
556 			break;
557 
558 
559 		/* Reset the LCD. */
560 		case HLCD_RESET:
561 			error = hd44780_init(sc);
562 			break;
563 
564 		/* Get the current cursor position. */
565 		case HLCD_GET_CURSOR_POS:
566 			hd44780_io()->dat = (hd44780_ir_read(sc, en) & 0x7f);
567 			break;
568 
569 		/* Set the cursor position. */
570 		case HLCD_SET_CURSOR_POS:
571 			hd44780_ir_write(sc, en, cmd_ddramset(hd44780_io()->dat));
572 			break;
573 
574 		/* Get the value at the current cursor position. */
575 		case HLCD_GETC:
576 			tmp = (hd44780_ir_read(sc, en) & 0x7f);
577 			hd44780_ir_write(sc, en, cmd_ddramset(tmp));
578 			hd44780_io()->dat = hd44780_dr_read(sc, en);
579 			break;
580 
581 		/* Set the character at the cursor position + advance cursor. */
582 		case HLCD_PUTC:
583 			hd44780_dr_write(sc, en, hd44780_io()->dat);
584 			break;
585 
586 		/* Shift display left. */
587 		case HLCD_SHIFT_LEFT:
588 			hd44780_ir_write(sc, en, cmd_shift(1, 0));
589 			break;
590 
591 		/* Shift display right. */
592 		case HLCD_SHIFT_RIGHT:
593 			hd44780_ir_write(sc, en, cmd_shift(1, 1));
594 			break;
595 
596 		/* Return home. */
597 		case HLCD_HOME:
598 			hd44780_ir_write(sc, en, cmd_rethome());
599 			break;
600 
601 		/* Write a string to the LCD virtual area. */
602 		case HLCD_WRITE:
603 			error = hd44780_ddram_io(sc, en, hd44780_io(), HD_DDRAM_WRITE);
604 			break;
605 
606 		/* Read LCD virtual area. */
607 		case HLCD_READ:
608 			error = hd44780_ddram_io(sc, en, hd44780_io(), HD_DDRAM_READ);
609 			break;
610 
611 		/* Write to the LCD visible area. */
612 		case HLCD_REDRAW:
613 			hd44780_ddram_redraw(sc, en, hd44780_io());
614 			break;
615 
616 		/* Write raw instruction. */
617 		case HLCD_WRITE_INST:
618 			hd44780_ir_write(sc, en, hd44780_io()->dat);
619 			break;
620 
621 		/* Write raw data. */
622 		case HLCD_WRITE_DATA:
623 			hd44780_dr_write(sc, en, hd44780_io()->dat);
624 			break;
625 
626 		/* Get current chip 0 or 1 (top or bottom) */
627 		case HLCD_GET_CHIPNO:
628 			*(u_int8_t *)data = sc->sc_curchip;
629 			break;
630 
631 		/* Set current chip 0 or 1 (top or bottom) */
632 		case HLCD_SET_CHIPNO:
633 			sc->sc_curchip = *(u_int8_t *)data;
634 			break;
635 
636 		default:
637 			error = EINVAL;
638 	}
639 
640 	if (sc->sc_flags & HD_TIMEDOUT)
641 		error = EIO;
642 
643 	return error;
644 }
645 
646 /*
647  * Read/write particular area of the LCD screen.
648  */
649 int
650 hd44780_ddram_io(sc, en, io, dir)
651 	struct hd44780_chip *sc;
652 	u_int32_t en;
653 	struct hd44780_io *io;
654 	u_char dir;
655 {
656 	u_int8_t hi;
657 	u_int8_t addr;
658 
659 	int error = 0;
660 	u_int8_t i = 0;
661 
662 	if (io->dat < sc->sc_vcols) {
663 		hi = HD_ROW1_ADDR + sc->sc_vcols;
664 		addr = HD_ROW1_ADDR + io->dat;
665 		for (; (addr < hi) && (i < io->len); addr++, i++) {
666 			hd44780_ir_write(sc, en, cmd_ddramset(addr));
667 			if (dir == HD_DDRAM_READ)
668 				io->buf[i] = hd44780_dr_read(sc, en);
669 			else
670 				hd44780_dr_write(sc, en, io->buf[i]);
671 		}
672 	}
673 	if (io->dat < 2 * sc->sc_vcols) {
674 		hi = HD_ROW2_ADDR + sc->sc_vcols;
675 		if (io->dat >= sc->sc_vcols)
676 			addr = HD_ROW2_ADDR + io->dat - sc->sc_vcols;
677 		else
678 			addr = HD_ROW2_ADDR;
679 		for (; (addr < hi) && (i < io->len); addr++, i++) {
680 			hd44780_ir_write(sc, en, cmd_ddramset(addr));
681 			if (dir == HD_DDRAM_READ)
682 				io->buf[i] = hd44780_dr_read(sc, en);
683 			else
684 				hd44780_dr_write(sc, en, io->buf[i]);
685 		}
686 		if (i < io->len)
687 			io->len = i;
688 	} else {
689 		error = EINVAL;
690 	}
691 	return error;
692 }
693 
694 /*
695  * Write to the visible area of the display.
696  */
697 void
698 hd44780_ddram_redraw(sc, en, io)
699 	struct hd44780_chip *sc;
700 	u_int32_t en;
701 	struct hd44780_io *io;
702 {
703 	u_int8_t i;
704 
705 	hd44780_ir_write(sc, en, cmd_clear());
706 	hd44780_ir_write(sc, en, cmd_rethome());
707 	hd44780_ir_write(sc, en, cmd_ddramset(HD_ROW1_ADDR));
708 	for (i = 0; (i < io->len) && (i < sc->sc_cols); i++) {
709 		hd44780_dr_write(sc, en, io->buf[i]);
710 	}
711 	hd44780_ir_write(sc, en, cmd_ddramset(HD_ROW2_ADDR));
712 	for (; (i < io->len); i++)
713 		hd44780_dr_write(sc, en, io->buf[i]);
714 }
715 
716 void
717 hd44780_busy_wait(sc, en)
718 	struct hd44780_chip *sc;
719 	u_int32_t en;
720 {
721 	int nloops = 100;
722 
723 	if (sc->sc_flags & HD_TIMEDOUT)
724 		return;
725 
726 	while(nloops-- && (hd44780_ir_read(sc, en) & BUSY_FLAG) == BUSY_FLAG);
727 
728 	if (nloops == 0) {
729 		sc->sc_flags |= HD_TIMEDOUT;
730 		sc->sc_dev_ok = 0;
731 	}
732 }
733 
734 #if defined(HD44780_STD_WIDE)
735 /*
736  * Standard 8-bit version of 'sc_writereg' (8-bit port, 8-bit access)
737  */
738 void
739 hd44780_writereg(sc, en, reg, cmd)
740 	struct hd44780_chip *sc;
741 	u_int32_t en, reg;
742 	u_int8_t cmd;
743 {
744 	bus_space_tag_t iot = sc->sc_iot;
745 	bus_space_handle_t ioh;
746 
747 	if (sc->sc_dev_ok == 0)
748 		return;
749 
750 	if (reg == 0)
751 		ioh = sc->sc_ioir;
752 	else
753 		ioh = sc->sc_iodr;
754 
755 	bus_space_write_1(iot, ioh, 0x00, cmd);
756 	delay(HD_TIMEOUT_NORMAL);
757 }
758 
759 /*
760  * Standard 8-bit version of 'sc_readreg' (8-bit port, 8-bit access)
761  */
762 u_int8_t
763 hd44780_readreg(sc, en, reg)
764 	struct hd44780_chip *sc;
765 	u_int32_t en, reg;
766 {
767 	bus_space_tag_t iot = sc->sc_iot;
768 	bus_space_handle_t ioh;
769 
770 	if (sc->sc_dev_ok == 0)
771 		return;
772 
773 	if (reg == 0)
774 		ioh = sc->sc_ioir;
775 	else
776 		ioh = sc->sc_iodr;
777 
778 	delay(HD_TIMEOUT_NORMAL);
779 	return bus_space_read_1(iot, ioh, 0x00);
780 }
781 #elif defined(HD44780_STD_SHORT)
782 /*
783  * Standard 4-bit version of 'sc_writereg' (4-bit port, 8-bit access)
784  */
785 void
786 hd44780_writereg(sc, en, reg, cmd)
787 	struct hd44780_chip *sc;
788 	u_int32_t en, reg;
789 	u_int8_t cmd;
790 {
791 	bus_space_tag_t iot = sc->sc_iot;
792 	bus_space_handle_t ioh;
793 
794 	if (sc->sc_dev_ok == 0)
795 		return;
796 
797 	if (reg == 0)
798 		ioh = sc->sc_ioir;
799 	else
800 		ioh = sc->sc_iodr;
801 
802 	bus_space_write_1(iot, ioh, 0x00, hi_bits(cmd));
803 	if (sc->sc_flags & HD_UP)
804 		bus_space_write_1(iot, ioh, 0x00, lo_bits(cmd));
805 	delay(HD_TIMEOUT_NORMAL);
806 }
807 
808 /*
809  * Standard 4-bit version of 'sc_readreg' (4-bit port, 8-bit access)
810  */
811 u_int8_t
812 hd44780_readreg(sc, en, reg)
813 	struct hd44780_chip *sc;
814 	u_int32_t en, reg;
815 {
816 	bus_space_tag_t iot = sc->sc_iot;
817 	bus_space_handle_t ioh;
818 	u_int8_t rd, dat;
819 
820 	if (sc->sc_dev_ok == 0)
821 		return;
822 
823 	if (reg == 0)
824 		ioh = sc->sc_ioir;
825 	else
826 		ioh = sc->sc_iodr;
827 
828 	rd = bus_space_read_1(iot, ioh, 0x00);
829 	dat = (rd & 0x0f) << 4;
830 	rd = bus_space_read_1(iot, ioh, 0x00);
831 	return (dat | (rd & 0x0f));
832 }
833 #endif
834