1 // SPDX-License-Identifier: GPL-2.0-or-later 2 #include <linux/hex.h> 3 #include <linux/module.h> 4 #include <linux/sched.h> 5 #include <linux/slab.h> 6 7 #include "charlcd.h" 8 #include "hd44780_common.h" 9 10 /* LCD commands */ 11 #define LCD_CMD_DISPLAY_CLEAR 0x01 /* Clear entire display */ 12 13 #define LCD_CMD_ENTRY_MODE 0x04 /* Set entry mode */ 14 #define LCD_CMD_CURSOR_INC 0x02 /* Increment cursor */ 15 16 #define LCD_CMD_DISPLAY_CTRL 0x08 /* Display control */ 17 #define LCD_CMD_DISPLAY_ON 0x04 /* Set display on */ 18 #define LCD_CMD_CURSOR_ON 0x02 /* Set cursor on */ 19 #define LCD_CMD_BLINK_ON 0x01 /* Set blink on */ 20 21 #define LCD_CMD_SHIFT 0x10 /* Shift cursor/display */ 22 #define LCD_CMD_DISPLAY_SHIFT 0x08 /* Shift display instead of cursor */ 23 #define LCD_CMD_SHIFT_RIGHT 0x04 /* Shift display/cursor to the right */ 24 25 #define LCD_CMD_FUNCTION_SET 0x20 /* Set function */ 26 #define LCD_CMD_DATA_LEN_8BITS 0x10 /* Set data length to 8 bits */ 27 #define LCD_CMD_TWO_LINES 0x08 /* Set to two display lines */ 28 #define LCD_CMD_FONT_5X10_DOTS 0x04 /* Set char font to 5x10 dots */ 29 30 #define LCD_CMD_SET_CGRAM_ADDR 0x40 /* Set char generator RAM address */ 31 32 #define LCD_CMD_SET_DDRAM_ADDR 0x80 /* Set display data RAM address */ 33 34 /* sleeps that many milliseconds with a reschedule */ 35 static void long_sleep(int ms) 36 { 37 schedule_timeout_interruptible(msecs_to_jiffies(ms)); 38 } 39 40 int hd44780_common_print(struct charlcd *lcd, int c) 41 { 42 struct hd44780_common *hdc = lcd->drvdata; 43 44 if (lcd->addr.x < hdc->bwidth) { 45 hdc->write_data(hdc, c); 46 return 0; 47 } 48 49 return 1; 50 } 51 EXPORT_SYMBOL_GPL(hd44780_common_print); 52 53 int hd44780_common_gotoxy(struct charlcd *lcd, unsigned int x, unsigned int y) 54 { 55 struct hd44780_common *hdc = lcd->drvdata; 56 unsigned int addr; 57 58 /* 59 * we force the cursor to stay at the end of the 60 * line if it wants to go farther 61 */ 62 addr = x < hdc->bwidth ? x & (hdc->hwidth - 1) : hdc->bwidth - 1; 63 if (y & 1) 64 addr += hdc->hwidth; 65 if (y & 2) 66 addr += hdc->bwidth; 67 hdc->write_cmd(hdc, LCD_CMD_SET_DDRAM_ADDR | addr); 68 return 0; 69 } 70 EXPORT_SYMBOL_GPL(hd44780_common_gotoxy); 71 72 int hd44780_common_home(struct charlcd *lcd) 73 { 74 return hd44780_common_gotoxy(lcd, 0, 0); 75 } 76 EXPORT_SYMBOL_GPL(hd44780_common_home); 77 78 /* clears the display and resets X/Y */ 79 int hd44780_common_clear_display(struct charlcd *lcd) 80 { 81 struct hd44780_common *hdc = lcd->drvdata; 82 83 hdc->write_cmd(hdc, LCD_CMD_DISPLAY_CLEAR); 84 /* datasheet says to wait 1,64 milliseconds */ 85 long_sleep(2); 86 87 /* 88 * The Hitachi HD44780 controller (and compatible ones) reset the DDRAM 89 * address when executing the DISPLAY_CLEAR command, thus the 90 * following call is not required. However, other controllers do not 91 * (e.g. NewHaven NHD-0220DZW-AG5), thus move the cursor to home 92 * unconditionally to support both. 93 */ 94 return hd44780_common_home(lcd); 95 } 96 EXPORT_SYMBOL_GPL(hd44780_common_clear_display); 97 98 int hd44780_common_init_display(struct charlcd *lcd) 99 { 100 struct hd44780_common *hdc = lcd->drvdata; 101 102 void (*write_cmd_raw)(struct hd44780_common *hdc, int cmd); 103 u8 init; 104 105 if (hdc->ifwidth != 4 && hdc->ifwidth != 8) 106 return -EINVAL; 107 108 hdc->hd44780_common_flags = ((lcd->height > 1) ? LCD_FLAG_N : 0) | 109 LCD_FLAG_D | LCD_FLAG_C | LCD_FLAG_B; 110 111 long_sleep(20); /* wait 20 ms after power-up for the paranoid */ 112 113 /* 114 * 8-bit mode, 1 line, small fonts; let's do it 3 times, to make sure 115 * the LCD is in 8-bit mode afterwards 116 */ 117 init = LCD_CMD_FUNCTION_SET | LCD_CMD_DATA_LEN_8BITS; 118 if (hdc->ifwidth == 4) { 119 init >>= 4; 120 write_cmd_raw = hdc->write_cmd_raw4; 121 } else { 122 write_cmd_raw = hdc->write_cmd; 123 } 124 write_cmd_raw(hdc, init); 125 long_sleep(10); 126 write_cmd_raw(hdc, init); 127 long_sleep(10); 128 write_cmd_raw(hdc, init); 129 long_sleep(10); 130 131 if (hdc->ifwidth == 4) { 132 /* Switch to 4-bit mode, 1 line, small fonts */ 133 hdc->write_cmd_raw4(hdc, LCD_CMD_FUNCTION_SET >> 4); 134 long_sleep(10); 135 } 136 137 /* set font height and lines number */ 138 hdc->write_cmd(hdc, 139 LCD_CMD_FUNCTION_SET | 140 ((hdc->ifwidth == 8) ? LCD_CMD_DATA_LEN_8BITS : 0) | 141 ((hdc->hd44780_common_flags & LCD_FLAG_F) ? 142 LCD_CMD_FONT_5X10_DOTS : 0) | 143 ((hdc->hd44780_common_flags & LCD_FLAG_N) ? 144 LCD_CMD_TWO_LINES : 0)); 145 long_sleep(10); 146 147 /* display off, cursor off, blink off */ 148 hdc->write_cmd(hdc, LCD_CMD_DISPLAY_CTRL); 149 long_sleep(10); 150 151 hdc->write_cmd(hdc, 152 LCD_CMD_DISPLAY_CTRL | /* set display mode */ 153 ((hdc->hd44780_common_flags & LCD_FLAG_D) ? 154 LCD_CMD_DISPLAY_ON : 0) | 155 ((hdc->hd44780_common_flags & LCD_FLAG_C) ? 156 LCD_CMD_CURSOR_ON : 0) | 157 ((hdc->hd44780_common_flags & LCD_FLAG_B) ? 158 LCD_CMD_BLINK_ON : 0)); 159 160 charlcd_backlight(lcd, 161 (hdc->hd44780_common_flags & LCD_FLAG_L) ? 1 : 0); 162 163 long_sleep(10); 164 165 /* entry mode set : increment, cursor shifting */ 166 hdc->write_cmd(hdc, LCD_CMD_ENTRY_MODE | LCD_CMD_CURSOR_INC); 167 168 hd44780_common_clear_display(lcd); 169 return 0; 170 } 171 EXPORT_SYMBOL_GPL(hd44780_common_init_display); 172 173 int hd44780_common_shift_cursor(struct charlcd *lcd, enum charlcd_shift_dir dir) 174 { 175 struct hd44780_common *hdc = lcd->drvdata; 176 177 if (dir == CHARLCD_SHIFT_LEFT) { 178 /* back one char if not at end of line */ 179 if (lcd->addr.x < hdc->bwidth) 180 hdc->write_cmd(hdc, LCD_CMD_SHIFT); 181 } else if (dir == CHARLCD_SHIFT_RIGHT) { 182 /* allow the cursor to pass the end of the line */ 183 if (lcd->addr.x < (hdc->bwidth - 1)) 184 hdc->write_cmd(hdc, 185 LCD_CMD_SHIFT | LCD_CMD_SHIFT_RIGHT); 186 } 187 188 return 0; 189 } 190 EXPORT_SYMBOL_GPL(hd44780_common_shift_cursor); 191 192 int hd44780_common_shift_display(struct charlcd *lcd, 193 enum charlcd_shift_dir dir) 194 { 195 struct hd44780_common *hdc = lcd->drvdata; 196 197 if (dir == CHARLCD_SHIFT_LEFT) 198 hdc->write_cmd(hdc, LCD_CMD_SHIFT | LCD_CMD_DISPLAY_SHIFT); 199 else if (dir == CHARLCD_SHIFT_RIGHT) 200 hdc->write_cmd(hdc, LCD_CMD_SHIFT | LCD_CMD_DISPLAY_SHIFT | 201 LCD_CMD_SHIFT_RIGHT); 202 203 return 0; 204 } 205 EXPORT_SYMBOL_GPL(hd44780_common_shift_display); 206 207 static void hd44780_common_set_mode(struct hd44780_common *hdc) 208 { 209 hdc->write_cmd(hdc, 210 LCD_CMD_DISPLAY_CTRL | 211 ((hdc->hd44780_common_flags & LCD_FLAG_D) ? 212 LCD_CMD_DISPLAY_ON : 0) | 213 ((hdc->hd44780_common_flags & LCD_FLAG_C) ? 214 LCD_CMD_CURSOR_ON : 0) | 215 ((hdc->hd44780_common_flags & LCD_FLAG_B) ? 216 LCD_CMD_BLINK_ON : 0)); 217 } 218 219 int hd44780_common_display(struct charlcd *lcd, enum charlcd_onoff on) 220 { 221 struct hd44780_common *hdc = lcd->drvdata; 222 223 if (on == CHARLCD_ON) 224 hdc->hd44780_common_flags |= LCD_FLAG_D; 225 else 226 hdc->hd44780_common_flags &= ~LCD_FLAG_D; 227 228 hd44780_common_set_mode(hdc); 229 return 0; 230 } 231 EXPORT_SYMBOL_GPL(hd44780_common_display); 232 233 int hd44780_common_cursor(struct charlcd *lcd, enum charlcd_onoff on) 234 { 235 struct hd44780_common *hdc = lcd->drvdata; 236 237 if (on == CHARLCD_ON) 238 hdc->hd44780_common_flags |= LCD_FLAG_C; 239 else 240 hdc->hd44780_common_flags &= ~LCD_FLAG_C; 241 242 hd44780_common_set_mode(hdc); 243 return 0; 244 } 245 EXPORT_SYMBOL_GPL(hd44780_common_cursor); 246 247 int hd44780_common_blink(struct charlcd *lcd, enum charlcd_onoff on) 248 { 249 struct hd44780_common *hdc = lcd->drvdata; 250 251 if (on == CHARLCD_ON) 252 hdc->hd44780_common_flags |= LCD_FLAG_B; 253 else 254 hdc->hd44780_common_flags &= ~LCD_FLAG_B; 255 256 hd44780_common_set_mode(hdc); 257 return 0; 258 } 259 EXPORT_SYMBOL_GPL(hd44780_common_blink); 260 261 static void hd44780_common_set_function(struct hd44780_common *hdc) 262 { 263 hdc->write_cmd(hdc, 264 LCD_CMD_FUNCTION_SET | 265 ((hdc->ifwidth == 8) ? LCD_CMD_DATA_LEN_8BITS : 0) | 266 ((hdc->hd44780_common_flags & LCD_FLAG_F) ? 267 LCD_CMD_FONT_5X10_DOTS : 0) | 268 ((hdc->hd44780_common_flags & LCD_FLAG_N) ? 269 LCD_CMD_TWO_LINES : 0)); 270 } 271 272 int hd44780_common_fontsize(struct charlcd *lcd, enum charlcd_fontsize size) 273 { 274 struct hd44780_common *hdc = lcd->drvdata; 275 276 if (size == CHARLCD_FONTSIZE_LARGE) 277 hdc->hd44780_common_flags |= LCD_FLAG_F; 278 else 279 hdc->hd44780_common_flags &= ~LCD_FLAG_F; 280 281 hd44780_common_set_function(hdc); 282 return 0; 283 } 284 EXPORT_SYMBOL_GPL(hd44780_common_fontsize); 285 286 int hd44780_common_lines(struct charlcd *lcd, enum charlcd_lines lines) 287 { 288 struct hd44780_common *hdc = lcd->drvdata; 289 290 if (lines == CHARLCD_LINES_2) 291 hdc->hd44780_common_flags |= LCD_FLAG_N; 292 else 293 hdc->hd44780_common_flags &= ~LCD_FLAG_N; 294 295 hd44780_common_set_function(hdc); 296 return 0; 297 } 298 EXPORT_SYMBOL_GPL(hd44780_common_lines); 299 300 int hd44780_common_redefine_char(struct charlcd *lcd, char *esc) 301 { 302 /* Generator : LGcxxxxx...xx; must have <c> between '0' 303 * and '7', representing the numerical ASCII code of the 304 * redefined character, and <xx...xx> a sequence of 16 305 * hex digits representing 8 bytes for each character. 306 * Most LCDs will only use 5 lower bits of the 7 first 307 * bytes. 308 */ 309 310 struct hd44780_common *hdc = lcd->drvdata; 311 unsigned char cgbytes[8]; 312 unsigned char cgaddr; 313 int cgoffset; 314 int shift; 315 char value; 316 int addr; 317 318 if (!strchr(esc, ';')) 319 return 0; 320 321 esc++; 322 323 cgaddr = *(esc++) - '0'; 324 if (cgaddr > 7) 325 return 1; 326 327 cgoffset = 0; 328 shift = 0; 329 value = 0; 330 while (*esc && cgoffset < 8) { 331 int half; 332 333 shift ^= 4; 334 half = hex_to_bin(*esc++); 335 if (half < 0) 336 continue; 337 338 value |= half << shift; 339 if (shift == 0) { 340 cgbytes[cgoffset++] = value; 341 value = 0; 342 } 343 } 344 345 hdc->write_cmd(hdc, LCD_CMD_SET_CGRAM_ADDR | (cgaddr * 8)); 346 for (addr = 0; addr < cgoffset; addr++) 347 hdc->write_data(hdc, cgbytes[addr]); 348 349 /* ensures that we stop writing to CGRAM */ 350 lcd->ops->gotoxy(lcd, lcd->addr.x, lcd->addr.y); 351 return 1; 352 } 353 EXPORT_SYMBOL_GPL(hd44780_common_redefine_char); 354 355 struct charlcd *hd44780_common_alloc(void) 356 { 357 struct hd44780_common *hdc; 358 struct charlcd *lcd; 359 360 lcd = charlcd_alloc(sizeof(*hdc)); 361 if (!lcd) 362 return NULL; 363 364 hdc = lcd->drvdata; 365 hdc->ifwidth = 8; 366 hdc->bwidth = DEFAULT_LCD_BWIDTH; 367 hdc->hwidth = DEFAULT_LCD_HWIDTH; 368 return lcd; 369 } 370 EXPORT_SYMBOL_GPL(hd44780_common_alloc); 371 372 void hd44780_common_free(struct charlcd *lcd) 373 { 374 charlcd_free(lcd); 375 } 376 EXPORT_SYMBOL_GPL(hd44780_common_free); 377 378 MODULE_DESCRIPTION("Common functions for HD44780 (and compatibles) LCD displays"); 379 MODULE_LICENSE("GPL"); 380