xref: /netbsd-src/sys/dev/ic/hd44780_subr.c (revision fd5cb0acea84d278e04e640d37ca2398f894991f)
1 /* $NetBSD: hd44780_subr.c,v 1.5 2005/02/04 05:58:44 joff 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 1.5 2005/02/04 05:58:44 joff 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) ? 1 : 0)
61 #define IDX_TO_COL(idx)		(((idx) >= sc->sc_cols) ? \
62 				((idx) - sc->sc_cols) : (idx))
63 #define IDX_TO_DDADDR(idx)	((IDX_TO_ROW((idx)) == 1) ? \
64 				(HD_ROW2_ADDR + IDX_TO_COL((idx))) : \
65 				(IDX_TO_COL((idx))))
66 #define DADDR_TO_ROW(daddr)	(((daddr) >= HD_ROW2_ADDR) ? 1 : 0)
67 #define DADDR_TO_COL(daddr)	((DADDR_TO_ROW((daddr)) == 1) ? \
68 				((daddr) - HD_ROW2_ADDR) : (daddr))
69 
70 static void	hlcd_cursor(void *, int, int, int);
71 static int	hlcd_mapchar(void *, int, unsigned int *);
72 static void	hlcd_putchar(void *, int, int, u_int, long);
73 static void	hlcd_copycols(void *, int, int, int,int);
74 static void	hlcd_erasecols(void *, int, int, int, long);
75 static void	hlcd_copyrows(void *, int, int, int);
76 static void	hlcd_eraserows(void *, int, int, long);
77 static int	hlcd_allocattr(void *, int, int, int, long *);
78 static void	hlcd_updatechar(struct hd44780_chip *, int, int);
79 static void	hlcd_redraw(void *);
80 
81 const struct wsdisplay_emulops hlcd_emulops = {
82 	hlcd_cursor,
83 	hlcd_mapchar,
84 	hlcd_putchar,
85 	hlcd_copycols,
86 	hlcd_erasecols,
87 	hlcd_copyrows,
88 	hlcd_eraserows,
89 	hlcd_allocattr
90 };
91 
92 static int	hlcd_ioctl(void *, u_long, caddr_t, int, struct proc *);
93 static paddr_t	hlcd_mmap(void *, off_t, int);
94 static int	hlcd_alloc_screen(void *, const struct wsscreen_descr *,
95 		    void **, int *, int *, long *);
96 static void	hlcd_free_screen(void *, void *);
97 static int	hlcd_show_screen(void *, void *, int,
98 		    void (*) (void *, int, int), void *);
99 
100 const struct wsdisplay_accessops hlcd_accessops = {
101 	hlcd_ioctl,
102 	hlcd_mmap,
103 	hlcd_alloc_screen,
104 	hlcd_free_screen,
105 	hlcd_show_screen,
106 	0 /* load_font */
107 };
108 
109 static void
110 hlcd_cursor(id, on, row, col)
111 	void *id;
112 	int on, row, col;
113 {
114 	struct hlcd_screen *hdscr = id;
115 
116 	hdscr->hlcd_curon = on;
117 	hdscr->hlcd_curx = col;
118 	hdscr->hlcd_cury = row;
119 }
120 
121 static int
122 hlcd_mapchar(id, uni, index)
123 	void *id;
124 	int uni;
125 	unsigned int *index;
126 {
127 	if (uni < 256) {
128 		*index = uni;
129 		return (5);
130 	}
131 	*index = ' ';
132 	return (0);
133 }
134 
135 static void
136 hlcd_putchar(id, row, col, c, attr)
137 	void *id;
138 	int row, col;
139 	u_int c;
140 	long attr;
141 {
142 	struct hlcd_screen *hdscr = id;
143 
144 	c &= 0xff;
145 	if (row > 0 && (hdscr->hlcd_sc->sc_flags & HD_MULTILINE))
146 		hdscr->image[hdscr->hlcd_sc->sc_cols * row + col] = c;
147 	else
148 		hdscr->image[col] = c;
149 }
150 
151 /*
152  * copies columns inside a row.
153  */
154 static void
155 hlcd_copycols(id, row, srccol, dstcol, ncols)
156 	void *id;
157 	int row, srccol, dstcol, ncols;
158 {
159 	struct hlcd_screen *hdscr = id;
160 
161 	if ((dstcol + ncols - 1) > hdscr->hlcd_sc->sc_cols)
162 		ncols = hdscr->hlcd_sc->sc_cols - srccol;
163 
164 	if (row > 0 && (hdscr->hlcd_sc->sc_flags & HD_MULTILINE))
165 		bcopy(&hdscr->image[hdscr->hlcd_sc->sc_cols * row + srccol],
166 		    &hdscr->image[hdscr->hlcd_sc->sc_cols * row + dstcol], ncols);
167 	else
168 		bcopy(&hdscr->image[srccol], &hdscr->image[dstcol], 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))
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))
203 		return;
204 	bcopy(&hdscr->image[srcrow * ncols], &hdscr->image[dstrow * 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, cmd, data, flag, p)
233 	void *v;
234 	u_long cmd;
235 	caddr_t data;
236 	int flag;
237 	struct proc *p;
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, offset, prot)
260 	void *v;
261 	off_t offset;
262 	int prot;
263 {
264 	return -1;
265 }
266 
267 static int
268 hlcd_alloc_screen(v, type, cookiep, curxp, curyp, defattrp)
269 	void *v;
270 	const struct wsscreen_descr *type;
271 	void **cookiep;
272 	int *curxp, *curyp;
273 	long *defattrp;
274 {
275 	struct hlcd_screen *hdscr = v, *new;
276 
277 	new = *cookiep = malloc(sizeof(struct hlcd_screen), M_DEVBUF, M_WAITOK);
278 	bzero(*cookiep, sizeof(struct hlcd_screen));
279 	new->hlcd_sc = hdscr->hlcd_sc;
280 	new->image = malloc(PAGE_SIZE, M_DEVBUF, M_WAITOK);
281 	memset(new->image, ' ', PAGE_SIZE);
282 	*curxp = *curyp = *defattrp = 0;
283 	return 0;
284 }
285 
286 static void
287 hlcd_free_screen(v, cookie)
288 	void *v, *cookie;
289 {
290 }
291 
292 static int
293 hlcd_show_screen(v, cookie, waitok, cb, cbarg)
294 	void *v, *cookie, *cbarg;
295 	int waitok;
296 	void (*cb)(void *, int, int);
297 {
298 	struct hlcd_screen *hdscr = v;
299 
300 	hdscr->hlcd_sc->sc_curscr = cookie;
301 	callout_schedule(&hdscr->hlcd_sc->redraw, 1);
302 	return (0);
303 }
304 
305 static void
306 hlcd_updatechar(sc, daddr, c)
307 	struct hd44780_chip *sc;
308 	int daddr, c;
309 {
310 	int curdaddr;
311 
312 	curdaddr = COORD_TO_DADDR(sc->sc_screen.hlcd_curx,
313 	    sc->sc_screen.hlcd_cury);
314 	if (daddr != curdaddr)
315 		hd44780_ir_write(sc, cmd_ddramset(daddr));
316 
317 	hd44780_dr_write(sc, c);
318 
319 	daddr++;
320 	sc->sc_screen.hlcd_curx = DADDR_TO_COL(daddr);
321 	sc->sc_screen.hlcd_cury = DADDR_TO_ROW(daddr);
322 }
323 
324 static void
325 hlcd_redraw(arg)
326 	void *arg;
327 {
328 	struct hd44780_chip *sc = arg;
329 	int len, crsridx, startidx, x, y;
330 	u_char *img, *curimg;
331 
332 	if (sc->sc_curscr == NULL)
333 		return;
334 
335 	if (sc->sc_flags & HD_MULTILINE)
336 		len = 2 * sc->sc_cols;
337 	else
338 		len = sc->sc_cols;
339 
340 	img = sc->sc_screen.image;
341 	curimg = sc->sc_curscr->image;
342 	startidx = crsridx =
343 	    COORD_TO_IDX(sc->sc_screen.hlcd_curx, sc->sc_screen.hlcd_cury);
344 	do {
345 		if (img[crsridx] != curimg[crsridx]) {
346 			hlcd_updatechar(sc, IDX_TO_DDADDR(crsridx),
347 			    curimg[crsridx]);
348 			img[crsridx] = curimg[crsridx];
349 		}
350 		crsridx++;
351 		if (crsridx == len)
352 			crsridx = 0;
353 	} while (crsridx != startidx);
354 
355 	if (sc->sc_screen.hlcd_curx != sc->sc_curscr->hlcd_curx ||
356 	    sc->sc_screen.hlcd_cury != sc->sc_curscr->hlcd_cury) {
357 		x = sc->sc_screen.hlcd_curx = sc->sc_curscr->hlcd_curx;
358 		y = sc->sc_screen.hlcd_cury = sc->sc_curscr->hlcd_cury;
359 		hd44780_ir_write(sc, cmd_ddramset(COORD_TO_DADDR(x, y)));
360 	}
361 
362 	if (sc->sc_screen.hlcd_curon != sc->sc_curscr->hlcd_curon) {
363 		sc->sc_screen.hlcd_curon = sc->sc_curscr->hlcd_curon;
364 		if (sc->sc_screen.hlcd_curon)
365 			hd44780_ir_write(sc, cmd_dispctl(1, 1, 1));
366 		else
367 			hd44780_ir_write(sc, cmd_dispctl(1, 0, 0));
368 	}
369 
370 	callout_schedule(&sc->redraw, 1);
371 }
372 
373 
374 /*
375  * Finish device attach. sc_writereg, sc_readreg and sc_flags must be properly
376  * initialized prior to this call.
377  */
378 void
379 hd44780_attach_subr(sc)
380 	struct hd44780_chip *sc;
381 {
382 	int err = 0;
383 	/* Putc/getc are supposed to be set by platform-dependent code. */
384 	if ((sc->sc_writereg == NULL) || (sc->sc_readreg == NULL))
385 		sc->sc_dev_ok = 0;
386 
387 	/* Make sure that HD_MAX_CHARS is enough. */
388 	if ((sc->sc_flags & HD_MULTILINE) && (2 * sc->sc_cols > HD_MAX_CHARS))
389 		sc->sc_dev_ok = 0;
390 	else if (sc->sc_cols > HD_MAX_CHARS)
391 		sc->sc_dev_ok = 0;
392 
393 	if (sc->sc_dev_ok) {
394 		if ((sc->sc_flags & HD_UP) == 0)
395 			err = hd44780_init(sc);
396 		if (err != 0)
397 			printf("%s: LCD not responding or unconnected\n", sc->sc_dev->dv_xname);
398 
399 	}
400 
401 	sc->sc_screen.hlcd_sc = sc;
402 
403 	sc->sc_screen.image = malloc(PAGE_SIZE, M_DEVBUF, M_WAITOK);
404 	memset(sc->sc_screen.image, ' ', PAGE_SIZE);
405 	sc->sc_curscr = NULL;
406 	callout_init(&sc->redraw);
407 	callout_setfunc(&sc->redraw, hlcd_redraw, sc);
408 }
409 
410 /*
411  * Initialize 4-bit or 8-bit connected device.
412  */
413 int
414 hd44780_init(sc)
415 	struct hd44780_chip *sc;
416 {
417 	u_int8_t cmd, dat;
418 
419 	sc->sc_flags &= ~(HD_TIMEDOUT|HD_UP);
420 	sc->sc_dev_ok = 1;
421 	cmd = cmd_init(sc->sc_flags & HD_8BIT);
422 	hd44780_ir_write(sc, cmd);
423 	delay(HD_TIMEOUT_LONG);
424 	hd44780_ir_write(sc, cmd);
425 	hd44780_ir_write(sc, cmd);
426 
427 	cmd = cmd_funcset(
428 			sc->sc_flags & HD_8BIT,
429 			sc->sc_flags & HD_MULTILINE,
430 			sc->sc_flags & HD_BIGFONT);
431 
432 	if ((sc->sc_flags & HD_8BIT) == 0)
433 		hd44780_ir_write(sc, cmd);
434 
435 	sc->sc_flags |= HD_UP;
436 
437 	hd44780_ir_write(sc, cmd);
438 	hd44780_ir_write(sc, cmd_dispctl(0, 0, 0));
439 	hd44780_ir_write(sc, cmd_clear());
440 	hd44780_ir_write(sc, cmd_modset(1, 0));
441 
442 	if (sc->sc_flags & HD_TIMEDOUT) {
443 		sc->sc_flags &= ~HD_UP;
444 		return EIO;
445 	}
446 
447 	/* Turn display on and clear it. */
448 	hd44780_ir_write(sc, cmd_clear());
449 	hd44780_ir_write(sc, cmd_dispctl(1, 0, 0));
450 
451 	/* Attempt a simple probe for presence */
452 	hd44780_ir_write(sc, cmd_ddramset(0x5));
453 	hd44780_ir_write(sc, cmd_shift(0, 1));
454 	hd44780_busy_wait(sc);
455 	if ((dat = hd44780_ir_read(sc) & 0x7f) != 0x6) {
456 		sc->sc_dev_ok = 0;
457 		sc->sc_flags &= ~HD_UP;
458 		return EIO;
459 	}
460 	hd44780_ir_write(sc, cmd_ddramset(0));
461 
462 	return 0;
463 }
464 
465 /*
466  * Standard hd44780 ioctl() functions.
467  */
468 int
469 hd44780_ioctl_subr(sc, cmd, data)
470 	struct hd44780_chip *sc;
471 	u_long cmd;
472 	caddr_t data;
473 {
474 	u_int8_t tmp;
475 	int error = 0;
476 
477 #define hd44780_io()	((struct hd44780_io *)data)
478 #define hd44780_info()	((struct hd44780_info*)data)
479 #define hd44780_ctrl()	((struct hd44780_dispctl*)data)
480 
481 	switch (cmd) {
482 		/* Clear the LCD. */
483 		case HLCD_CLEAR:
484 			hd44780_ir_write(sc, cmd_clear());
485 			break;
486 
487 		/* Move the cursor one position to the left. */
488 		case HLCD_CURSOR_LEFT:
489 			hd44780_ir_write(sc, cmd_shift(0, 0));
490 			break;
491 
492 		/* Move the cursor one position to the right. */
493 		case HLCD_CURSOR_RIGHT:
494 			hd44780_ir_write(sc, cmd_shift(0, 1));
495 			break;
496 
497 		/* Control the LCD. */
498 		case HLCD_DISPCTL:
499 			hd44780_ir_write(sc, cmd_dispctl(
500 						hd44780_ctrl()->display_on,
501 						hd44780_ctrl()->cursor_on,
502 						hd44780_ctrl()->blink_on));
503 			break;
504 
505 		/* Get LCD configuration. */
506 		case HLCD_GET_INFO:
507 			hd44780_info()->lines
508 				= (sc->sc_flags & HD_MULTILINE) ? 2 : 1;
509 			hd44780_info()->phys_rows = sc->sc_cols;
510 			hd44780_info()->virt_rows = sc->sc_vcols;
511 			hd44780_info()->is_wide = sc->sc_flags & HD_8BIT;
512 			hd44780_info()->is_bigfont = sc->sc_flags & HD_BIGFONT;
513 			hd44780_info()->kp_present = sc->sc_flags & HD_KEYPAD;
514 			break;
515 
516 
517 		/* Reset the LCD. */
518 		case HLCD_RESET:
519 			error = hd44780_init(sc);
520 			break;
521 
522 		/* Get the current cursor position. */
523 		case HLCD_GET_CURSOR_POS:
524 			hd44780_io()->dat = (hd44780_ir_read(sc) & 0x7f);
525 			break;
526 
527 		/* Set the cursor position. */
528 		case HLCD_SET_CURSOR_POS:
529 			hd44780_ir_write(sc, cmd_ddramset(hd44780_io()->dat));
530 			break;
531 
532 		/* Get the value at the current cursor position. */
533 		case HLCD_GETC:
534 			tmp = (hd44780_ir_read(sc) & 0x7f);
535 			hd44780_ir_write(sc, cmd_ddramset(tmp));
536 			hd44780_io()->dat = hd44780_dr_read(sc);
537 			break;
538 
539 		/* Set the character at the cursor position + advance cursor. */
540 		case HLCD_PUTC:
541 			hd44780_dr_write(sc, hd44780_io()->dat);
542 			break;
543 
544 		/* Shift display left. */
545 		case HLCD_SHIFT_LEFT:
546 			hd44780_ir_write(sc, cmd_shift(1, 0));
547 			break;
548 
549 		/* Shift display right. */
550 		case HLCD_SHIFT_RIGHT:
551 			hd44780_ir_write(sc, cmd_shift(1, 1));
552 			break;
553 
554 		/* Return home. */
555 		case HLCD_HOME:
556 			hd44780_ir_write(sc, cmd_rethome());
557 			break;
558 
559 		/* Write a string to the LCD virtual area. */
560 		case HLCD_WRITE:
561 			error = hd44780_ddram_io(sc, hd44780_io(), HD_DDRAM_WRITE);
562 			break;
563 
564 		/* Read LCD virtual area. */
565 		case HLCD_READ:
566 			error = hd44780_ddram_io(sc, hd44780_io(), HD_DDRAM_READ);
567 			break;
568 
569 		/* Write to the LCD visible area. */
570 		case HLCD_REDRAW:
571 			hd44780_ddram_redraw(sc, hd44780_io());
572 			break;
573 
574 		/* Write raw instruction. */
575 		case HLCD_WRITE_INST:
576 			hd44780_ir_write(sc, hd44780_io()->dat);
577 			break;
578 
579 		/* Write raw data. */
580 		case HLCD_WRITE_DATA:
581 			hd44780_dr_write(sc, hd44780_io()->dat);
582 			break;
583 
584 		default:
585 			error = EINVAL;
586 	}
587 
588 	if (sc->sc_flags & HD_TIMEDOUT)
589 		error = EIO;
590 
591 	return error;
592 }
593 
594 /*
595  * Read/write particular area of the LCD screen.
596  */
597 int
598 hd44780_ddram_io(sc, io, dir)
599 	struct hd44780_chip *sc;
600 	struct hd44780_io *io;
601 	u_char dir;
602 {
603 	u_int8_t hi;
604 	u_int8_t addr;
605 
606 	int error = 0;
607 	u_int8_t i = 0;
608 
609 	if (io->dat < sc->sc_vcols) {
610 		hi = HD_ROW1_ADDR + sc->sc_vcols;
611 		addr = HD_ROW1_ADDR + io->dat;
612 		for (; (addr < hi) && (i < io->len); addr++, i++) {
613 			hd44780_ir_write(sc, cmd_ddramset(addr));
614 			if (dir == HD_DDRAM_READ)
615 				io->buf[i] = hd44780_dr_read(sc);
616 			else
617 				hd44780_dr_write(sc, io->buf[i]);
618 		}
619 	}
620 	if (io->dat < 2 * sc->sc_vcols) {
621 		hi = HD_ROW2_ADDR + sc->sc_vcols;
622 		if (io->dat >= sc->sc_vcols)
623 			addr = HD_ROW2_ADDR + io->dat - sc->sc_vcols;
624 		else
625 			addr = HD_ROW2_ADDR;
626 		for (; (addr < hi) && (i < io->len); addr++, i++) {
627 			hd44780_ir_write(sc, cmd_ddramset(addr));
628 			if (dir == HD_DDRAM_READ)
629 				io->buf[i] = hd44780_dr_read(sc);
630 			else
631 				hd44780_dr_write(sc, io->buf[i]);
632 		}
633 		if (i < io->len)
634 			io->len = i;
635 	} else {
636 		error = EINVAL;
637 	}
638 	return error;
639 }
640 
641 /*
642  * Write to the visible area of the display.
643  */
644 void
645 hd44780_ddram_redraw(sc, io)
646 	struct hd44780_chip *sc;
647 	struct hd44780_io *io;
648 {
649 	u_int8_t i;
650 
651 	hd44780_ir_write(sc, cmd_clear());
652 	hd44780_ir_write(sc, cmd_rethome());
653 	for (i = 0; (i < io->len) && (i < sc->sc_cols); i++) {
654 		hd44780_dr_write(sc, io->buf[i]);
655 	}
656 	hd44780_ir_write(sc, cmd_ddramset(HD_ROW2_ADDR));
657 	for (; (i < io->len); i++)
658 		hd44780_dr_write(sc, io->buf[i]);
659 }
660 
661 void
662 hd44780_busy_wait(sc)
663 	struct hd44780_chip *sc;
664 {
665 	int nloops = 100;
666 
667 	if (sc->sc_flags & HD_TIMEDOUT)
668 		return;
669 
670 	while(nloops-- && (hd44780_ir_read(sc) & BUSY_FLAG) == BUSY_FLAG);
671 
672 	if (nloops == 0) {
673 		sc->sc_flags |= HD_TIMEDOUT;
674 		sc->sc_dev_ok = 0;
675 	}
676 }
677 
678 #if defined(HD44780_STD_WIDE)
679 /*
680  * Standard 8-bit version of 'sc_writereg' (8-bit port, 8-bit access)
681  */
682 void
683 hd44780_writereg(sc, reg, cmd)
684 	struct hd44780_chip *sc;
685 	u_int32_t reg;
686 	u_int8_t cmd;
687 {
688 	bus_space_tag_t iot = sc->sc_iot;
689 	bus_space_handle_t ioh;
690 
691 	if (sc->sc_dev_ok == 0)
692 		return;
693 
694 	if (reg == 0)
695 		ioh = sc->sc_ioir;
696 	else
697 		ioh = sc->sc_iodr;
698 
699 	bus_space_write_1(iot, ioh, 0x00, cmd);
700 	delay(HD_TIMEOUT_NORMAL);
701 }
702 
703 /*
704  * Standard 8-bit version of 'sc_readreg' (8-bit port, 8-bit access)
705  */
706 u_int8_t
707 hd44780_readreg(sc, reg)
708 	struct hd44780_chip *sc;
709 	u_int32_t reg;
710 {
711 	bus_space_tag_t iot = sc->sc_iot;
712 	bus_space_handle_t ioh;
713 
714 	if (sc->sc_dev_ok == 0)
715 		return;
716 
717 	if (reg == 0)
718 		ioh = sc->sc_ioir;
719 	else
720 		ioh = sc->sc_iodr;
721 
722 	delay(HD_TIMEOUT_NORMAL);
723 	return bus_space_read_1(iot, ioh, 0x00);
724 }
725 #elif defined(HD44780_STD_SHORT)
726 /*
727  * Standard 4-bit version of 'sc_writereg' (4-bit port, 8-bit access)
728  */
729 void
730 hd44780_writereg(sc, reg, cmd)
731 	struct hd44780_chip *sc;
732 	u_int32_t reg;
733 	u_int8_t cmd;
734 {
735 	bus_space_tag_t iot = sc->sc_iot;
736 	bus_space_handle_t ioh;
737 
738 	if (sc->sc_dev_ok == 0)
739 		return;
740 
741 	if (reg == 0)
742 		ioh = sc->sc_ioir;
743 	else
744 		ioh = sc->sc_iodr;
745 
746 	bus_space_write_1(iot, ioh, 0x00, hi_bits(cmd));
747 	if (sc->sc_flags & HD_UP)
748 		bus_space_write_1(iot, ioh, 0x00, lo_bits(cmd));
749 	delay(HD_TIMEOUT_NORMAL);
750 }
751 
752 /*
753  * Standard 4-bit version of 'sc_readreg' (4-bit port, 8-bit access)
754  */
755 u_int8_t
756 hd44780_readreg(sc, reg)
757 	struct hd44780_chip *sc;
758 	u_int32_t reg;
759 {
760 	bus_space_tag_t iot = sc->sc_iot;
761 	bus_space_handle_t ioh;
762 	u_int8_t rd, dat;
763 
764 	if (sc->sc_dev_ok == 0)
765 		return;
766 
767 	if (reg == 0)
768 		ioh = sc->sc_ioir;
769 	else
770 		ioh = sc->sc_iodr;
771 
772 	rd = bus_space_read_1(iot, ioh, 0x00);
773 	dat = (rd & 0x0f) << 4;
774 	rd = bus_space_read_1(iot, ioh, 0x00);
775 	return (dat | (rd & 0x0f));
776 }
777 #endif
778