xref: /netbsd-src/sys/dev/ic/hd44780_subr.c (revision bbde328be4e75ea9ad02e9715ea13ca54b797ada)
1 /* $NetBSD: hd44780_subr.c,v 1.20 2009/08/30 02:07:05 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 1.20 2009/08/30 02:07:05 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(void *id, int on, int row, int col)
110 {
111 	struct hlcd_screen *hdscr = id;
112 
113 	hdscr->hlcd_curon = on;
114 	hdscr->hlcd_curx = col;
115 	hdscr->hlcd_cury = row;
116 }
117 
118 static int
119 hlcd_mapchar(void *id, int uni, unsigned int *index)
120 {
121 
122 	if (uni < 256) {
123 		*index = uni;
124 		return 5;
125 	}
126 	*index = ' ';
127 	return 0;
128 }
129 
130 static void
131 hlcd_putchar(void *id, int row, int col, u_int c, long attr)
132 {
133 	struct hlcd_screen *hdscr = id;
134 
135 	c &= 0xff;
136 	if (row > 0 && (hdscr->hlcd_sc->sc_flags & (HD_MULTILINE|HD_MULTICHIP)))
137 		hdscr->image[hdscr->hlcd_sc->sc_cols * row + col] = c;
138 	else
139 		hdscr->image[col] = c;
140 }
141 
142 /*
143  * copies columns inside a row.
144  */
145 static void
146 hlcd_copycols(void *id, int row, int srccol, int dstcol, int ncols)
147 {
148 	struct hlcd_screen *hdscr = id;
149 
150 	if ((dstcol + ncols - 1) > hdscr->hlcd_sc->sc_cols)
151 		ncols = hdscr->hlcd_sc->sc_cols - srccol;
152 
153 	if (row > 0 && (hdscr->hlcd_sc->sc_flags & (HD_MULTILINE|HD_MULTICHIP)))
154 		memmove(&hdscr->image[hdscr->hlcd_sc->sc_cols * row + dstcol],
155 		    &hdscr->image[hdscr->hlcd_sc->sc_cols * row + srccol],
156 		    ncols);
157 	else
158 		memmove(&hdscr->image[dstcol], &hdscr->image[srccol], ncols);
159 }
160 
161 
162 /*
163  * Erases a bunch of chars inside one row.
164  */
165 static void
166 hlcd_erasecols(void *id, int row, int startcol, int ncols, long fillattr)
167 {
168 	struct hlcd_screen *hdscr = id;
169 
170 	if ((startcol + ncols) > hdscr->hlcd_sc->sc_cols)
171 		ncols = hdscr->hlcd_sc->sc_cols - startcol;
172 
173 	if (row > 0 && (hdscr->hlcd_sc->sc_flags & (HD_MULTILINE|HD_MULTICHIP)))
174 		memset(&hdscr->image[hdscr->hlcd_sc->sc_cols * row + startcol],
175 		    ' ', ncols);
176 	else
177 		memset(&hdscr->image[startcol], ' ', ncols);
178 }
179 
180 
181 static void
182 hlcd_copyrows(void *id, int srcrow, int dstrow, int nrows)
183 {
184 	struct hlcd_screen *hdscr = id;
185 	int ncols = hdscr->hlcd_sc->sc_cols;
186 
187 	if (!(hdscr->hlcd_sc->sc_flags & (HD_MULTILINE|HD_MULTICHIP)))
188 		return;
189 	memmove(&hdscr->image[dstrow * ncols], &hdscr->image[srcrow * ncols],
190 	    nrows * ncols);
191 }
192 
193 static void
194 hlcd_eraserows(void *id, int startrow, int nrows, long fillattr)
195 {
196 	struct hlcd_screen *hdscr = id;
197 	int ncols = hdscr->hlcd_sc->sc_cols;
198 
199 	memset(&hdscr->image[startrow * ncols], ' ', ncols * nrows);
200 }
201 
202 
203 static int
204 hlcd_allocattr(void *id, int fg, int bg, int flags, long *attrp)
205 {
206 
207         *attrp = flags;
208         return 0;
209 }
210 
211 static int
212 hlcd_ioctl(void *v, void *vs, u_long cmd, void *data, int flag, struct lwp *l)
213 {
214 
215 	switch (cmd) {
216 	case WSDISPLAYIO_GTYPE:
217 		*(u_int *)data = WSDISPLAY_TYPE_HDLCD;
218 		break;
219 
220 	case WSDISPLAYIO_SVIDEO:
221 		break;
222 
223 	case WSDISPLAYIO_GVIDEO:
224 		*(u_int *)data = WSDISPLAYIO_VIDEO_ON;
225 		break;
226 
227 	default:
228 		return EPASSTHROUGH;
229 	}
230 	return 0;
231 }
232 
233 static paddr_t
234 hlcd_mmap(void *v, void *vs, off_t offset, int prot)
235 {
236 
237 	return -1;
238 }
239 
240 static int
241 hlcd_alloc_screen(void *v, const struct wsscreen_descr *type, void **cookiep,
242     int *curxp, int *curyp, long *defattrp)
243 {
244 	struct hlcd_screen *hdscr = v, *new;
245 
246 	new = *cookiep = malloc(sizeof(struct hlcd_screen),
247 				M_DEVBUF, M_WAITOK|M_ZERO);
248 	new->hlcd_sc = hdscr->hlcd_sc;
249 	new->image = malloc(PAGE_SIZE, M_DEVBUF, M_WAITOK);
250 	memset(new->image, ' ', PAGE_SIZE);
251 	*curxp = *curyp = *defattrp = 0;
252 	return 0;
253 }
254 
255 static void
256 hlcd_free_screen(void *v, void *cookie)
257 {
258 }
259 
260 static int
261 hlcd_show_screen(void *v, void *cookie, int waitok,
262     void (*cb)(void *, int, int), void *cbarg)
263 {
264 	struct hlcd_screen *hdscr = v;
265 
266 	hdscr->hlcd_sc->sc_curscr = cookie;
267 	callout_schedule(&hdscr->hlcd_sc->redraw, 1);
268 	return 0;
269 }
270 
271 static void
272 hlcd_updatechar(struct hd44780_chip *sc, int daddr, int c)
273 {
274 	int curdaddr, en, chipdaddr;
275 
276 	curdaddr = COORD_TO_DADDR(sc->sc_screen.hlcd_curx,
277 	    sc->sc_screen.hlcd_cury);
278 	en = DADDR_TO_CHIPNO(daddr);
279 	chipdaddr = DADDR_TO_CHIPDADDR(daddr);
280 	if (daddr != curdaddr)
281 		hd44780_ir_write(sc, en, cmd_ddramset(chipdaddr));
282 
283 	hd44780_dr_write(sc, en, c);
284 
285 	daddr++;
286 	sc->sc_screen.hlcd_curx = DADDR_TO_COL(daddr);
287 	sc->sc_screen.hlcd_cury = DADDR_TO_ROW(daddr);
288 }
289 
290 static void
291 hlcd_redraw(void *arg)
292 {
293 	struct hd44780_chip *sc = arg;
294 	int len, crsridx, startidx, x, y;
295 	int old_en, new_en;
296 	uint8_t *img, *curimg;
297 
298 	if (sc->sc_curscr == NULL)
299 		return;
300 
301 	if (sc->sc_flags & HD_MULTILINE)
302 		len = 2 * sc->sc_cols;
303 	else
304 		len = sc->sc_cols;
305 
306 	if (sc->sc_flags & HD_MULTICHIP)
307 		len = len * 2;
308 
309 	x = sc->sc_screen.hlcd_curx;
310 	y = sc->sc_screen.hlcd_cury;
311 	old_en = DADDR_TO_CHIPNO(COORD_TO_DADDR(x, y));
312 
313 	img = sc->sc_screen.image;
314 	curimg = sc->sc_curscr->image;
315 	startidx = crsridx =
316 	    COORD_TO_IDX(sc->sc_screen.hlcd_curx, sc->sc_screen.hlcd_cury);
317 	do {
318 		if (img[crsridx] != curimg[crsridx]) {
319 			hlcd_updatechar(sc, IDX_TO_DADDR(crsridx),
320 			    curimg[crsridx]);
321 			img[crsridx] = curimg[crsridx];
322 		}
323 		crsridx++;
324 		if (crsridx == len)
325 			crsridx = 0;
326 	} while (crsridx != startidx);
327 
328 	x = sc->sc_curscr->hlcd_curx;
329 	y = sc->sc_curscr->hlcd_cury;
330 	new_en = DADDR_TO_CHIPNO(COORD_TO_DADDR(x, y));
331 
332 	if (sc->sc_screen.hlcd_curx != sc->sc_curscr->hlcd_curx ||
333 	    sc->sc_screen.hlcd_cury != sc->sc_curscr->hlcd_cury) {
334 
335 		x = sc->sc_screen.hlcd_curx = sc->sc_curscr->hlcd_curx;
336 		y = sc->sc_screen.hlcd_cury = sc->sc_curscr->hlcd_cury;
337 
338 		hd44780_ir_write(sc, new_en, cmd_ddramset(
339 		    DADDR_TO_CHIPDADDR(COORD_TO_DADDR(x, y))));
340 
341 	}
342 
343 	/* visible cursor switched to other chip */
344 	if (old_en != new_en && sc->sc_screen.hlcd_curon) {
345 		hd44780_ir_write(sc, old_en, cmd_dispctl(1, 0, 0));
346 		hd44780_ir_write(sc, new_en, cmd_dispctl(1, 1, 1));
347 	}
348 
349 	if (sc->sc_screen.hlcd_curon != sc->sc_curscr->hlcd_curon) {
350 		sc->sc_screen.hlcd_curon = sc->sc_curscr->hlcd_curon;
351 		if (sc->sc_screen.hlcd_curon)
352 			hd44780_ir_write(sc, new_en, cmd_dispctl(1, 1, 1));
353 		else
354 			hd44780_ir_write(sc, new_en, cmd_dispctl(1, 0, 0));
355 	}
356 
357 	callout_schedule(&sc->redraw, 1);
358 }
359 
360 
361 /*
362  * Finish device attach. sc_writereg, sc_readreg and sc_flags must be properly
363  * initialized prior to this call.
364  */
365 void
366 hd44780_attach_subr(struct hd44780_chip *sc)
367 {
368 	int err = 0;
369 
370 	/* Putc/getc are supposed to be set by platform-dependent code. */
371 	if ((sc->sc_writereg == NULL) || (sc->sc_readreg == NULL))
372 		sc->sc_dev_ok = 0;
373 
374 	/* Make sure that HD_MAX_CHARS is enough. */
375 	if ((sc->sc_flags & HD_MULTILINE) && (2 * sc->sc_cols > HD_MAX_CHARS))
376 		sc->sc_dev_ok = 0;
377 	else if (sc->sc_cols > HD_MAX_CHARS)
378 		sc->sc_dev_ok = 0;
379 
380 	if (sc->sc_dev_ok) {
381 		if ((sc->sc_flags & HD_UP) == 0)
382 			err = hd44780_init(sc);
383 		if (err != 0)
384 			aprint_error_dev(sc->sc_dev,
385 			    "LCD not responding or unconnected\n");
386 	}
387 
388 	sc->sc_screen.hlcd_sc = sc;
389 
390 	sc->sc_screen.image = malloc(PAGE_SIZE, M_DEVBUF, M_WAITOK);
391 	memset(sc->sc_screen.image, ' ', PAGE_SIZE);
392 	sc->sc_curscr = NULL;
393 	sc->sc_curchip = 0;
394 	callout_init(&sc->redraw, 0);
395 	callout_setfunc(&sc->redraw, hlcd_redraw, sc);
396 }
397 
398 int hd44780_init(struct hd44780_chip *sc)
399 {
400 	int ret;
401 
402 	ret = hd44780_chipinit(sc, 0);
403 	if (ret != 0 || !(sc->sc_flags & HD_MULTICHIP))
404 		return ret;
405 	else
406 		return hd44780_chipinit(sc, 1);
407 }
408 
409 /*
410  * Initialize 4-bit or 8-bit connected device.
411  */
412 int
413 hd44780_chipinit(struct hd44780_chip *sc, uint32_t en)
414 {
415 	uint8_t cmd, dat;
416 
417 	sc->sc_flags &= ~(HD_TIMEDOUT|HD_UP);
418 	sc->sc_dev_ok = 1;
419 
420 	cmd = cmd_init(sc->sc_flags & HD_8BIT);
421 	hd44780_ir_write(sc, en, cmd);
422 	delay(HD_TIMEOUT_LONG);
423 	hd44780_ir_write(sc, en, cmd);
424 	hd44780_ir_write(sc, en, cmd);
425 
426 	cmd = cmd_funcset(
427 			sc->sc_flags & HD_8BIT,
428 			sc->sc_flags & HD_MULTILINE,
429 			sc->sc_flags & HD_BIGFONT);
430 
431 	if ((sc->sc_flags & HD_8BIT) == 0)
432 		hd44780_ir_write(sc, en, cmd);
433 
434 	sc->sc_flags |= HD_UP;
435 
436 	hd44780_ir_write(sc, en, cmd);
437 	hd44780_ir_write(sc, en, cmd_dispctl(0, 0, 0));
438 	hd44780_ir_write(sc, en, cmd_clear());
439 	hd44780_ir_write(sc, en, cmd_modset(1, 0));
440 
441 	if (sc->sc_flags & HD_TIMEDOUT) {
442 		sc->sc_flags &= ~HD_UP;
443 		return EIO;
444 	}
445 
446 	/* Turn display on and clear it. */
447 	hd44780_ir_write(sc, en, cmd_clear());
448 	hd44780_ir_write(sc, en, cmd_dispctl(1, 0, 0));
449 
450 	/* Attempt a simple probe for presence */
451 	hd44780_ir_write(sc, en, cmd_ddramset(0x5));
452 	hd44780_ir_write(sc, en, cmd_shift(0, 1));
453 	hd44780_busy_wait(sc, en);
454 	if ((dat = hd44780_ir_read(sc, en) & 0x7f) != 0x6) {
455 		sc->sc_dev_ok = 0;
456 		sc->sc_flags &= ~HD_UP;
457 		return EIO;
458 	}
459 	hd44780_ir_write(sc, en, cmd_ddramset(0));
460 
461 	return 0;
462 }
463 
464 /*
465  * Standard hd44780 ioctl() functions.
466  */
467 int
468 hd44780_ioctl_subr(struct hd44780_chip *sc, u_long cmd, void *data)
469 {
470 	uint8_t tmp;
471 	int error = 0;
472 	uint32_t en = sc->sc_curchip;
473 
474 #define hd44780_io()	((struct hd44780_io *)data)
475 #define hd44780_info()	((struct hd44780_info *)data)
476 #define hd44780_ctrl()	((struct hd44780_dispctl *)data)
477 
478 	switch (cmd) {
479 	case HLCD_CLEAR:
480 		/* Clear the LCD. */
481 		hd44780_ir_write(sc, en, cmd_clear());
482 		break;
483 
484 	case HLCD_CURSOR_LEFT:
485 		/* Move the cursor one position to the left. */
486 		hd44780_ir_write(sc, en, cmd_shift(0, 0));
487 			break;
488 
489 	case HLCD_CURSOR_RIGHT:
490 		/* Move the cursor one position to the right. */
491 		hd44780_ir_write(sc, en, cmd_shift(0, 1));
492 		break;
493 
494 	case HLCD_DISPCTL:
495 		/* Control the LCD. */
496 		hd44780_ir_write(sc, en, cmd_dispctl(
497 					hd44780_ctrl()->display_on,
498 					hd44780_ctrl()->cursor_on,
499 					hd44780_ctrl()->blink_on));
500 		break;
501 
502 	case HLCD_GET_INFO:
503 		/* Get LCD configuration. */
504 		hd44780_info()->lines
505 			= (sc->sc_flags & HD_MULTILINE) ? 2 : 1;
506 		if (sc->sc_flags & HD_MULTICHIP)
507 			hd44780_info()->lines *= 2;
508 		hd44780_info()->phys_rows = sc->sc_cols;
509 		hd44780_info()->virt_rows = sc->sc_vcols;
510 		hd44780_info()->is_wide = sc->sc_flags & HD_8BIT;
511 		hd44780_info()->is_bigfont = sc->sc_flags & HD_BIGFONT;
512 		hd44780_info()->kp_present = sc->sc_flags & HD_KEYPAD;
513 		break;
514 
515 
516 	case HLCD_RESET:
517 		/* Reset the LCD. */
518 		error = hd44780_init(sc);
519 		break;
520 
521 	case HLCD_GET_CURSOR_POS:
522 		/* Get the current cursor position. */
523 		hd44780_io()->dat = (hd44780_ir_read(sc, en) & 0x7f);
524 		break;
525 
526 	case HLCD_SET_CURSOR_POS:
527 		/* Set the cursor position. */
528 		hd44780_ir_write(sc, en, cmd_ddramset(hd44780_io()->dat));
529 		break;
530 
531 	case HLCD_GETC:
532 		/* Get the value at the current cursor position. */
533 		tmp = (hd44780_ir_read(sc, en) & 0x7f);
534 		hd44780_ir_write(sc, en, cmd_ddramset(tmp));
535 		hd44780_io()->dat = hd44780_dr_read(sc, en);
536 		break;
537 
538 	case HLCD_PUTC:
539 		/* Set the character at the cursor position + advance cursor. */
540 		hd44780_dr_write(sc, en, hd44780_io()->dat);
541 		break;
542 
543 	case HLCD_SHIFT_LEFT:
544 		/* Shift display left. */
545 		hd44780_ir_write(sc, en, cmd_shift(1, 0));
546 		break;
547 
548 	case HLCD_SHIFT_RIGHT:
549 		/* Shift display right. */
550 		hd44780_ir_write(sc, en, cmd_shift(1, 1));
551 		break;
552 
553 	case HLCD_HOME:
554 		/* Return home. */
555 		hd44780_ir_write(sc, en, cmd_rethome());
556 		break;
557 
558 	case HLCD_WRITE:
559 		/* Write a string to the LCD virtual area. */
560 		error = hd44780_ddram_io(sc, en, hd44780_io(), HD_DDRAM_WRITE);
561 		break;
562 
563 	case HLCD_READ:
564 		/* Read LCD virtual area. */
565 		error = hd44780_ddram_io(sc, en, hd44780_io(), HD_DDRAM_READ);
566 		break;
567 
568 	case HLCD_REDRAW:
569 		/* Write to the LCD visible area. */
570 		hd44780_ddram_redraw(sc, en, hd44780_io());
571 		break;
572 
573 	case HLCD_WRITE_INST:
574 		/* Write raw instruction. */
575 		hd44780_ir_write(sc, en, hd44780_io()->dat);
576 		break;
577 
578 	case HLCD_WRITE_DATA:
579 		/* Write raw data. */
580 		hd44780_dr_write(sc, en, hd44780_io()->dat);
581 		break;
582 
583 	case HLCD_GET_CHIPNO:
584 		/* Get current chip 0 or 1 (top or bottom) */
585 		*(uint8_t *)data = sc->sc_curchip;
586 		break;
587 
588 	case HLCD_SET_CHIPNO:
589 		/* Set current chip 0 or 1 (top or bottom) */
590 		sc->sc_curchip = *(uint8_t *)data;
591 		break;
592 
593 	default:
594 		error = EINVAL;
595 	}
596 
597 	if (sc->sc_flags & HD_TIMEDOUT)
598 		error = EIO;
599 
600 	return error;
601 }
602 
603 /*
604  * Read/write particular area of the LCD screen.
605  */
606 int
607 hd44780_ddram_io(struct hd44780_chip *sc, uint32_t en, struct hd44780_io *io,
608     uint8_t dir)
609 {
610 	uint8_t hi;
611 	uint8_t addr;
612 	int error = 0;
613 	uint8_t i = 0;
614 
615 	if (io->dat < sc->sc_vcols) {
616 		hi = HD_ROW1_ADDR + sc->sc_vcols;
617 		addr = HD_ROW1_ADDR + io->dat;
618 		for (; (addr < hi) && (i < io->len); addr++, i++) {
619 			hd44780_ir_write(sc, en, cmd_ddramset(addr));
620 			if (dir == HD_DDRAM_READ)
621 				io->buf[i] = hd44780_dr_read(sc, en);
622 			else
623 				hd44780_dr_write(sc, en, io->buf[i]);
624 		}
625 	}
626 	if (io->dat < 2 * sc->sc_vcols) {
627 		hi = HD_ROW2_ADDR + sc->sc_vcols;
628 		if (io->dat >= sc->sc_vcols)
629 			addr = HD_ROW2_ADDR + io->dat - sc->sc_vcols;
630 		else
631 			addr = HD_ROW2_ADDR;
632 		for (; (addr < hi) && (i < io->len); addr++, i++) {
633 			hd44780_ir_write(sc, en, cmd_ddramset(addr));
634 			if (dir == HD_DDRAM_READ)
635 				io->buf[i] = hd44780_dr_read(sc, en);
636 			else
637 				hd44780_dr_write(sc, en, io->buf[i]);
638 		}
639 		if (i < io->len)
640 			io->len = i;
641 	} else {
642 		error = EINVAL;
643 	}
644 	return error;
645 }
646 
647 /*
648  * Write to the visible area of the display.
649  */
650 void
651 hd44780_ddram_redraw(struct hd44780_chip *sc, uint32_t en,
652     struct hd44780_io *io)
653 {
654 	uint8_t i;
655 
656 	hd44780_ir_write(sc, en, cmd_clear());
657 	hd44780_ir_write(sc, en, cmd_rethome());
658 	hd44780_ir_write(sc, en, cmd_ddramset(HD_ROW1_ADDR));
659 	for (i = 0; (i < io->len) && (i < sc->sc_cols); i++) {
660 		hd44780_dr_write(sc, en, io->buf[i]);
661 	}
662 	hd44780_ir_write(sc, en, cmd_ddramset(HD_ROW2_ADDR));
663 	for (; (i < io->len); i++)
664 		hd44780_dr_write(sc, en, io->buf[i]);
665 }
666 
667 void
668 hd44780_busy_wait(struct hd44780_chip *sc, uint32_t en)
669 {
670 	int nloops = 100;
671 
672 	if (sc->sc_flags & HD_TIMEDOUT)
673 		return;
674 
675 	while (nloops-- && (hd44780_ir_read(sc, en) & BUSY_FLAG) == BUSY_FLAG)
676 		continue;
677 
678 	if (nloops == 0) {
679 		sc->sc_flags |= HD_TIMEDOUT;
680 		sc->sc_dev_ok = 0;
681 	}
682 }
683 
684 #if defined(HD44780_STD_WIDE)
685 /*
686  * Standard 8-bit version of 'sc_writereg' (8-bit port, 8-bit access)
687  */
688 void
689 hd44780_writereg(struct hd44780_chip *sc, uint32_t en, uint32_t reg,
690     uint8_t cmd)
691 {
692 	bus_space_tag_t iot = sc->sc_iot;
693 	bus_space_handle_t ioh;
694 
695 	if (sc->sc_dev_ok == 0)
696 		return;
697 
698 	if (reg == 0)
699 		ioh = sc->sc_ioir;
700 	else
701 		ioh = sc->sc_iodr;
702 
703 	bus_space_write_1(iot, ioh, 0x00, cmd);
704 	delay(HD_TIMEOUT_NORMAL);
705 }
706 
707 /*
708  * Standard 8-bit version of 'sc_readreg' (8-bit port, 8-bit access)
709  */
710 uint8_t
711 hd44780_readreg(struct hd44780_chip *sc, uint32_t en, uint32_t reg)
712 {
713 	bus_space_tag_t iot = sc->sc_iot;
714 	bus_space_handle_t ioh;
715 
716 	if (sc->sc_dev_ok == 0)
717 		return;
718 
719 	if (reg == 0)
720 		ioh = sc->sc_ioir;
721 	else
722 		ioh = sc->sc_iodr;
723 
724 	delay(HD_TIMEOUT_NORMAL);
725 	return bus_space_read_1(iot, ioh, 0x00);
726 }
727 #elif defined(HD44780_STD_SHORT)
728 /*
729  * Standard 4-bit version of 'sc_writereg' (4-bit port, 8-bit access)
730  */
731 void
732 hd44780_writereg(struct hd44780_chip *sc, uint32_t en, uint32_t reg,
733     uint8_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 uint8_t
756 hd44780_readreg(struct hd44780_chip *sc, uint32_t en, uint32_t reg)
757 {
758 	bus_space_tag_t iot = sc->sc_iot;
759 	bus_space_handle_t ioh;
760 	uint8_t rd, dat;
761 
762 	if (sc->sc_dev_ok == 0)
763 		return;
764 
765 	if (reg == 0)
766 		ioh = sc->sc_ioir;
767 	else
768 		ioh = sc->sc_iodr;
769 
770 	rd = bus_space_read_1(iot, ioh, 0x00);
771 	dat = (rd & 0x0f) << 4;
772 	rd = bus_space_read_1(iot, ioh, 0x00);
773 	return (dat | (rd & 0x0f));
774 }
775 #endif
776