1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | #include <linux/module.h> |
3 | #include <linux/sched.h> |
4 | #include <linux/slab.h> |
5 | |
6 | #include "charlcd.h" |
7 | #include "hd44780_common.h" |
8 | |
9 | /* LCD commands */ |
10 | #define LCD_CMD_DISPLAY_CLEAR 0x01 /* Clear entire display */ |
11 | |
12 | #define LCD_CMD_ENTRY_MODE 0x04 /* Set entry mode */ |
13 | #define LCD_CMD_CURSOR_INC 0x02 /* Increment cursor */ |
14 | |
15 | #define LCD_CMD_DISPLAY_CTRL 0x08 /* Display control */ |
16 | #define LCD_CMD_DISPLAY_ON 0x04 /* Set display on */ |
17 | #define LCD_CMD_CURSOR_ON 0x02 /* Set cursor on */ |
18 | #define LCD_CMD_BLINK_ON 0x01 /* Set blink on */ |
19 | |
20 | #define LCD_CMD_SHIFT 0x10 /* Shift cursor/display */ |
21 | #define LCD_CMD_DISPLAY_SHIFT 0x08 /* Shift display instead of cursor */ |
22 | #define LCD_CMD_SHIFT_RIGHT 0x04 /* Shift display/cursor to the right */ |
23 | |
24 | #define LCD_CMD_FUNCTION_SET 0x20 /* Set function */ |
25 | #define LCD_CMD_DATA_LEN_8BITS 0x10 /* Set data length to 8 bits */ |
26 | #define LCD_CMD_TWO_LINES 0x08 /* Set to two display lines */ |
27 | #define LCD_CMD_FONT_5X10_DOTS 0x04 /* Set char font to 5x10 dots */ |
28 | |
29 | #define LCD_CMD_SET_CGRAM_ADDR 0x40 /* Set char generator RAM address */ |
30 | |
31 | #define LCD_CMD_SET_DDRAM_ADDR 0x80 /* Set display data RAM address */ |
32 | |
33 | /* sleeps that many milliseconds with a reschedule */ |
34 | static void long_sleep(int ms) |
35 | { |
36 | schedule_timeout_interruptible(timeout: msecs_to_jiffies(m: ms)); |
37 | } |
38 | |
39 | int hd44780_common_print(struct charlcd *lcd, int c) |
40 | { |
41 | struct hd44780_common *hdc = lcd->drvdata; |
42 | |
43 | if (lcd->addr.x < hdc->bwidth) { |
44 | hdc->write_data(hdc, c); |
45 | return 0; |
46 | } |
47 | |
48 | return 1; |
49 | } |
50 | EXPORT_SYMBOL_GPL(hd44780_common_print); |
51 | |
52 | int hd44780_common_gotoxy(struct charlcd *lcd, unsigned int x, unsigned int y) |
53 | { |
54 | struct hd44780_common *hdc = lcd->drvdata; |
55 | unsigned int addr; |
56 | |
57 | /* |
58 | * we force the cursor to stay at the end of the |
59 | * line if it wants to go farther |
60 | */ |
61 | addr = x < hdc->bwidth ? x & (hdc->hwidth - 1) : hdc->bwidth - 1; |
62 | if (y & 1) |
63 | addr += hdc->hwidth; |
64 | if (y & 2) |
65 | addr += hdc->bwidth; |
66 | hdc->write_cmd(hdc, LCD_CMD_SET_DDRAM_ADDR | addr); |
67 | return 0; |
68 | } |
69 | EXPORT_SYMBOL_GPL(hd44780_common_gotoxy); |
70 | |
71 | int hd44780_common_home(struct charlcd *lcd) |
72 | { |
73 | return hd44780_common_gotoxy(lcd, 0, 0); |
74 | } |
75 | EXPORT_SYMBOL_GPL(hd44780_common_home); |
76 | |
77 | /* clears the display and resets X/Y */ |
78 | int hd44780_common_clear_display(struct charlcd *lcd) |
79 | { |
80 | struct hd44780_common *hdc = lcd->drvdata; |
81 | |
82 | hdc->write_cmd(hdc, LCD_CMD_DISPLAY_CLEAR); |
83 | /* datasheet says to wait 1,64 milliseconds */ |
84 | long_sleep(ms: 2); |
85 | |
86 | /* |
87 | * The Hitachi HD44780 controller (and compatible ones) reset the DDRAM |
88 | * address when executing the DISPLAY_CLEAR command, thus the |
89 | * following call is not required. However, other controllers do not |
90 | * (e.g. NewHaven NHD-0220DZW-AG5), thus move the cursor to home |
91 | * unconditionally to support both. |
92 | */ |
93 | return hd44780_common_home(lcd); |
94 | } |
95 | EXPORT_SYMBOL_GPL(hd44780_common_clear_display); |
96 | |
97 | int hd44780_common_init_display(struct charlcd *lcd) |
98 | { |
99 | struct hd44780_common *hdc = lcd->drvdata; |
100 | |
101 | void (*write_cmd_raw)(struct hd44780_common *hdc, int cmd); |
102 | u8 init; |
103 | |
104 | if (hdc->ifwidth != 4 && hdc->ifwidth != 8) |
105 | return -EINVAL; |
106 | |
107 | hdc->hd44780_common_flags = ((lcd->height > 1) ? LCD_FLAG_N : 0) | |
108 | LCD_FLAG_D | LCD_FLAG_C | LCD_FLAG_B; |
109 | |
110 | long_sleep(ms: 20); /* wait 20 ms after power-up for the paranoid */ |
111 | |
112 | /* |
113 | * 8-bit mode, 1 line, small fonts; let's do it 3 times, to make sure |
114 | * the LCD is in 8-bit mode afterwards |
115 | */ |
116 | init = LCD_CMD_FUNCTION_SET | LCD_CMD_DATA_LEN_8BITS; |
117 | if (hdc->ifwidth == 4) { |
118 | init >>= 4; |
119 | write_cmd_raw = hdc->write_cmd_raw4; |
120 | } else { |
121 | write_cmd_raw = hdc->write_cmd; |
122 | } |
123 | write_cmd_raw(hdc, init); |
124 | long_sleep(ms: 10); |
125 | write_cmd_raw(hdc, init); |
126 | long_sleep(ms: 10); |
127 | write_cmd_raw(hdc, init); |
128 | long_sleep(ms: 10); |
129 | |
130 | if (hdc->ifwidth == 4) { |
131 | /* Switch to 4-bit mode, 1 line, small fonts */ |
132 | hdc->write_cmd_raw4(hdc, LCD_CMD_FUNCTION_SET >> 4); |
133 | long_sleep(ms: 10); |
134 | } |
135 | |
136 | /* set font height and lines number */ |
137 | hdc->write_cmd(hdc, |
138 | LCD_CMD_FUNCTION_SET | |
139 | ((hdc->ifwidth == 8) ? LCD_CMD_DATA_LEN_8BITS : 0) | |
140 | ((hdc->hd44780_common_flags & LCD_FLAG_F) ? |
141 | LCD_CMD_FONT_5X10_DOTS : 0) | |
142 | ((hdc->hd44780_common_flags & LCD_FLAG_N) ? |
143 | LCD_CMD_TWO_LINES : 0)); |
144 | long_sleep(ms: 10); |
145 | |
146 | /* display off, cursor off, blink off */ |
147 | hdc->write_cmd(hdc, LCD_CMD_DISPLAY_CTRL); |
148 | long_sleep(ms: 10); |
149 | |
150 | hdc->write_cmd(hdc, |
151 | LCD_CMD_DISPLAY_CTRL | /* set display mode */ |
152 | ((hdc->hd44780_common_flags & LCD_FLAG_D) ? |
153 | LCD_CMD_DISPLAY_ON : 0) | |
154 | ((hdc->hd44780_common_flags & LCD_FLAG_C) ? |
155 | LCD_CMD_CURSOR_ON : 0) | |
156 | ((hdc->hd44780_common_flags & LCD_FLAG_B) ? |
157 | LCD_CMD_BLINK_ON : 0)); |
158 | |
159 | charlcd_backlight(lcd, |
160 | on: (hdc->hd44780_common_flags & LCD_FLAG_L) ? 1 : 0); |
161 | |
162 | long_sleep(ms: 10); |
163 | |
164 | /* entry mode set : increment, cursor shifting */ |
165 | hdc->write_cmd(hdc, LCD_CMD_ENTRY_MODE | LCD_CMD_CURSOR_INC); |
166 | |
167 | hd44780_common_clear_display(lcd); |
168 | return 0; |
169 | } |
170 | EXPORT_SYMBOL_GPL(hd44780_common_init_display); |
171 | |
172 | int hd44780_common_shift_cursor(struct charlcd *lcd, enum charlcd_shift_dir dir) |
173 | { |
174 | struct hd44780_common *hdc = lcd->drvdata; |
175 | |
176 | if (dir == CHARLCD_SHIFT_LEFT) { |
177 | /* back one char if not at end of line */ |
178 | if (lcd->addr.x < hdc->bwidth) |
179 | hdc->write_cmd(hdc, LCD_CMD_SHIFT); |
180 | } else if (dir == CHARLCD_SHIFT_RIGHT) { |
181 | /* allow the cursor to pass the end of the line */ |
182 | if (lcd->addr.x < (hdc->bwidth - 1)) |
183 | hdc->write_cmd(hdc, |
184 | LCD_CMD_SHIFT | LCD_CMD_SHIFT_RIGHT); |
185 | } |
186 | |
187 | return 0; |
188 | } |
189 | EXPORT_SYMBOL_GPL(hd44780_common_shift_cursor); |
190 | |
191 | int hd44780_common_shift_display(struct charlcd *lcd, |
192 | enum charlcd_shift_dir dir) |
193 | { |
194 | struct hd44780_common *hdc = lcd->drvdata; |
195 | |
196 | if (dir == CHARLCD_SHIFT_LEFT) |
197 | hdc->write_cmd(hdc, LCD_CMD_SHIFT | LCD_CMD_DISPLAY_SHIFT); |
198 | else if (dir == CHARLCD_SHIFT_RIGHT) |
199 | hdc->write_cmd(hdc, LCD_CMD_SHIFT | LCD_CMD_DISPLAY_SHIFT | |
200 | LCD_CMD_SHIFT_RIGHT); |
201 | |
202 | return 0; |
203 | } |
204 | EXPORT_SYMBOL_GPL(hd44780_common_shift_display); |
205 | |
206 | static void hd44780_common_set_mode(struct hd44780_common *hdc) |
207 | { |
208 | hdc->write_cmd(hdc, |
209 | LCD_CMD_DISPLAY_CTRL | |
210 | ((hdc->hd44780_common_flags & LCD_FLAG_D) ? |
211 | LCD_CMD_DISPLAY_ON : 0) | |
212 | ((hdc->hd44780_common_flags & LCD_FLAG_C) ? |
213 | LCD_CMD_CURSOR_ON : 0) | |
214 | ((hdc->hd44780_common_flags & LCD_FLAG_B) ? |
215 | LCD_CMD_BLINK_ON : 0)); |
216 | } |
217 | |
218 | int hd44780_common_display(struct charlcd *lcd, enum charlcd_onoff on) |
219 | { |
220 | struct hd44780_common *hdc = lcd->drvdata; |
221 | |
222 | if (on == CHARLCD_ON) |
223 | hdc->hd44780_common_flags |= LCD_FLAG_D; |
224 | else |
225 | hdc->hd44780_common_flags &= ~LCD_FLAG_D; |
226 | |
227 | hd44780_common_set_mode(hdc); |
228 | return 0; |
229 | } |
230 | EXPORT_SYMBOL_GPL(hd44780_common_display); |
231 | |
232 | int hd44780_common_cursor(struct charlcd *lcd, enum charlcd_onoff on) |
233 | { |
234 | struct hd44780_common *hdc = lcd->drvdata; |
235 | |
236 | if (on == CHARLCD_ON) |
237 | hdc->hd44780_common_flags |= LCD_FLAG_C; |
238 | else |
239 | hdc->hd44780_common_flags &= ~LCD_FLAG_C; |
240 | |
241 | hd44780_common_set_mode(hdc); |
242 | return 0; |
243 | } |
244 | EXPORT_SYMBOL_GPL(hd44780_common_cursor); |
245 | |
246 | int hd44780_common_blink(struct charlcd *lcd, enum charlcd_onoff on) |
247 | { |
248 | struct hd44780_common *hdc = lcd->drvdata; |
249 | |
250 | if (on == CHARLCD_ON) |
251 | hdc->hd44780_common_flags |= LCD_FLAG_B; |
252 | else |
253 | hdc->hd44780_common_flags &= ~LCD_FLAG_B; |
254 | |
255 | hd44780_common_set_mode(hdc); |
256 | return 0; |
257 | } |
258 | EXPORT_SYMBOL_GPL(hd44780_common_blink); |
259 | |
260 | static void hd44780_common_set_function(struct hd44780_common *hdc) |
261 | { |
262 | hdc->write_cmd(hdc, |
263 | LCD_CMD_FUNCTION_SET | |
264 | ((hdc->ifwidth == 8) ? LCD_CMD_DATA_LEN_8BITS : 0) | |
265 | ((hdc->hd44780_common_flags & LCD_FLAG_F) ? |
266 | LCD_CMD_FONT_5X10_DOTS : 0) | |
267 | ((hdc->hd44780_common_flags & LCD_FLAG_N) ? |
268 | LCD_CMD_TWO_LINES : 0)); |
269 | } |
270 | |
271 | int hd44780_common_fontsize(struct charlcd *lcd, enum charlcd_fontsize size) |
272 | { |
273 | struct hd44780_common *hdc = lcd->drvdata; |
274 | |
275 | if (size == CHARLCD_FONTSIZE_LARGE) |
276 | hdc->hd44780_common_flags |= LCD_FLAG_F; |
277 | else |
278 | hdc->hd44780_common_flags &= ~LCD_FLAG_F; |
279 | |
280 | hd44780_common_set_function(hdc); |
281 | return 0; |
282 | } |
283 | EXPORT_SYMBOL_GPL(hd44780_common_fontsize); |
284 | |
285 | int hd44780_common_lines(struct charlcd *lcd, enum charlcd_lines lines) |
286 | { |
287 | struct hd44780_common *hdc = lcd->drvdata; |
288 | |
289 | if (lines == CHARLCD_LINES_2) |
290 | hdc->hd44780_common_flags |= LCD_FLAG_N; |
291 | else |
292 | hdc->hd44780_common_flags &= ~LCD_FLAG_N; |
293 | |
294 | hd44780_common_set_function(hdc); |
295 | return 0; |
296 | } |
297 | EXPORT_SYMBOL_GPL(hd44780_common_lines); |
298 | |
299 | int hd44780_common_redefine_char(struct charlcd *lcd, char *esc) |
300 | { |
301 | /* Generator : LGcxxxxx...xx; must have <c> between '0' |
302 | * and '7', representing the numerical ASCII code of the |
303 | * redefined character, and <xx...xx> a sequence of 16 |
304 | * hex digits representing 8 bytes for each character. |
305 | * Most LCDs will only use 5 lower bits of the 7 first |
306 | * bytes. |
307 | */ |
308 | |
309 | struct hd44780_common *hdc = lcd->drvdata; |
310 | unsigned char cgbytes[8]; |
311 | unsigned char cgaddr; |
312 | int cgoffset; |
313 | int shift; |
314 | char value; |
315 | int addr; |
316 | |
317 | if (!strchr(esc, ';')) |
318 | return 0; |
319 | |
320 | esc++; |
321 | |
322 | cgaddr = *(esc++) - '0'; |
323 | if (cgaddr > 7) |
324 | return 1; |
325 | |
326 | cgoffset = 0; |
327 | shift = 0; |
328 | value = 0; |
329 | while (*esc && cgoffset < 8) { |
330 | int half; |
331 | |
332 | shift ^= 4; |
333 | half = hex_to_bin(ch: *esc++); |
334 | if (half < 0) |
335 | continue; |
336 | |
337 | value |= half << shift; |
338 | if (shift == 0) { |
339 | cgbytes[cgoffset++] = value; |
340 | value = 0; |
341 | } |
342 | } |
343 | |
344 | hdc->write_cmd(hdc, LCD_CMD_SET_CGRAM_ADDR | (cgaddr * 8)); |
345 | for (addr = 0; addr < cgoffset; addr++) |
346 | hdc->write_data(hdc, cgbytes[addr]); |
347 | |
348 | /* ensures that we stop writing to CGRAM */ |
349 | lcd->ops->gotoxy(lcd, lcd->addr.x, lcd->addr.y); |
350 | return 1; |
351 | } |
352 | EXPORT_SYMBOL_GPL(hd44780_common_redefine_char); |
353 | |
354 | struct hd44780_common *hd44780_common_alloc(void) |
355 | { |
356 | struct hd44780_common *hd; |
357 | |
358 | hd = kzalloc(size: sizeof(*hd), GFP_KERNEL); |
359 | if (!hd) |
360 | return NULL; |
361 | |
362 | hd->ifwidth = 8; |
363 | hd->bwidth = DEFAULT_LCD_BWIDTH; |
364 | hd->hwidth = DEFAULT_LCD_HWIDTH; |
365 | return hd; |
366 | } |
367 | EXPORT_SYMBOL_GPL(hd44780_common_alloc); |
368 | |
369 | MODULE_LICENSE("GPL" ); |
370 | |