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(msecs_to_jiffies(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(2); 85 return 0; 86 } 87 EXPORT_SYMBOL_GPL(hd44780_common_clear_display); 88 89 int hd44780_common_init_display(struct charlcd *lcd) 90 { 91 struct hd44780_common *hdc = lcd->drvdata; 92 93 void (*write_cmd_raw)(struct hd44780_common *hdc, int cmd); 94 u8 init; 95 96 if (hdc->ifwidth != 4 && hdc->ifwidth != 8) 97 return -EINVAL; 98 99 hdc->hd44780_common_flags = ((lcd->height > 1) ? LCD_FLAG_N : 0) | 100 LCD_FLAG_D | LCD_FLAG_C | LCD_FLAG_B; 101 102 long_sleep(20); /* wait 20 ms after power-up for the paranoid */ 103 104 /* 105 * 8-bit mode, 1 line, small fonts; let's do it 3 times, to make sure 106 * the LCD is in 8-bit mode afterwards 107 */ 108 init = LCD_CMD_FUNCTION_SET | LCD_CMD_DATA_LEN_8BITS; 109 if (hdc->ifwidth == 4) { 110 init >>= 4; 111 write_cmd_raw = hdc->write_cmd_raw4; 112 } else { 113 write_cmd_raw = hdc->write_cmd; 114 } 115 write_cmd_raw(hdc, init); 116 long_sleep(10); 117 write_cmd_raw(hdc, init); 118 long_sleep(10); 119 write_cmd_raw(hdc, init); 120 long_sleep(10); 121 122 if (hdc->ifwidth == 4) { 123 /* Switch to 4-bit mode, 1 line, small fonts */ 124 hdc->write_cmd_raw4(hdc, LCD_CMD_FUNCTION_SET >> 4); 125 long_sleep(10); 126 } 127 128 /* set font height and lines number */ 129 hdc->write_cmd(hdc, 130 LCD_CMD_FUNCTION_SET | 131 ((hdc->ifwidth == 8) ? LCD_CMD_DATA_LEN_8BITS : 0) | 132 ((hdc->hd44780_common_flags & LCD_FLAG_F) ? 133 LCD_CMD_FONT_5X10_DOTS : 0) | 134 ((hdc->hd44780_common_flags & LCD_FLAG_N) ? 135 LCD_CMD_TWO_LINES : 0)); 136 long_sleep(10); 137 138 /* display off, cursor off, blink off */ 139 hdc->write_cmd(hdc, LCD_CMD_DISPLAY_CTRL); 140 long_sleep(10); 141 142 hdc->write_cmd(hdc, 143 LCD_CMD_DISPLAY_CTRL | /* set display mode */ 144 ((hdc->hd44780_common_flags & LCD_FLAG_D) ? 145 LCD_CMD_DISPLAY_ON : 0) | 146 ((hdc->hd44780_common_flags & LCD_FLAG_C) ? 147 LCD_CMD_CURSOR_ON : 0) | 148 ((hdc->hd44780_common_flags & LCD_FLAG_B) ? 149 LCD_CMD_BLINK_ON : 0)); 150 151 charlcd_backlight(lcd, 152 (hdc->hd44780_common_flags & LCD_FLAG_L) ? 1 : 0); 153 154 long_sleep(10); 155 156 /* entry mode set : increment, cursor shifting */ 157 hdc->write_cmd(hdc, LCD_CMD_ENTRY_MODE | LCD_CMD_CURSOR_INC); 158 159 hd44780_common_clear_display(lcd); 160 return 0; 161 } 162 EXPORT_SYMBOL_GPL(hd44780_common_init_display); 163 164 int hd44780_common_shift_cursor(struct charlcd *lcd, enum charlcd_shift_dir dir) 165 { 166 struct hd44780_common *hdc = lcd->drvdata; 167 168 if (dir == CHARLCD_SHIFT_LEFT) { 169 /* back one char if not at end of line */ 170 if (lcd->addr.x < hdc->bwidth) 171 hdc->write_cmd(hdc, LCD_CMD_SHIFT); 172 } else if (dir == CHARLCD_SHIFT_RIGHT) { 173 /* allow the cursor to pass the end of the line */ 174 if (lcd->addr.x < (hdc->bwidth - 1)) 175 hdc->write_cmd(hdc, 176 LCD_CMD_SHIFT | LCD_CMD_SHIFT_RIGHT); 177 } 178 179 return 0; 180 } 181 EXPORT_SYMBOL_GPL(hd44780_common_shift_cursor); 182 183 int hd44780_common_shift_display(struct charlcd *lcd, 184 enum charlcd_shift_dir dir) 185 { 186 struct hd44780_common *hdc = lcd->drvdata; 187 188 if (dir == CHARLCD_SHIFT_LEFT) 189 hdc->write_cmd(hdc, LCD_CMD_SHIFT | LCD_CMD_DISPLAY_SHIFT); 190 else if (dir == CHARLCD_SHIFT_RIGHT) 191 hdc->write_cmd(hdc, LCD_CMD_SHIFT | LCD_CMD_DISPLAY_SHIFT | 192 LCD_CMD_SHIFT_RIGHT); 193 194 return 0; 195 } 196 EXPORT_SYMBOL_GPL(hd44780_common_shift_display); 197 198 static void hd44780_common_set_mode(struct hd44780_common *hdc) 199 { 200 hdc->write_cmd(hdc, 201 LCD_CMD_DISPLAY_CTRL | 202 ((hdc->hd44780_common_flags & LCD_FLAG_D) ? 203 LCD_CMD_DISPLAY_ON : 0) | 204 ((hdc->hd44780_common_flags & LCD_FLAG_C) ? 205 LCD_CMD_CURSOR_ON : 0) | 206 ((hdc->hd44780_common_flags & LCD_FLAG_B) ? 207 LCD_CMD_BLINK_ON : 0)); 208 } 209 210 int hd44780_common_display(struct charlcd *lcd, enum charlcd_onoff on) 211 { 212 struct hd44780_common *hdc = lcd->drvdata; 213 214 if (on == CHARLCD_ON) 215 hdc->hd44780_common_flags |= LCD_FLAG_D; 216 else 217 hdc->hd44780_common_flags &= ~LCD_FLAG_D; 218 219 hd44780_common_set_mode(hdc); 220 return 0; 221 } 222 EXPORT_SYMBOL_GPL(hd44780_common_display); 223 224 int hd44780_common_cursor(struct charlcd *lcd, enum charlcd_onoff on) 225 { 226 struct hd44780_common *hdc = lcd->drvdata; 227 228 if (on == CHARLCD_ON) 229 hdc->hd44780_common_flags |= LCD_FLAG_C; 230 else 231 hdc->hd44780_common_flags &= ~LCD_FLAG_C; 232 233 hd44780_common_set_mode(hdc); 234 return 0; 235 } 236 EXPORT_SYMBOL_GPL(hd44780_common_cursor); 237 238 int hd44780_common_blink(struct charlcd *lcd, enum charlcd_onoff on) 239 { 240 struct hd44780_common *hdc = lcd->drvdata; 241 242 if (on == CHARLCD_ON) 243 hdc->hd44780_common_flags |= LCD_FLAG_B; 244 else 245 hdc->hd44780_common_flags &= ~LCD_FLAG_B; 246 247 hd44780_common_set_mode(hdc); 248 return 0; 249 } 250 EXPORT_SYMBOL_GPL(hd44780_common_blink); 251 252 static void hd44780_common_set_function(struct hd44780_common *hdc) 253 { 254 hdc->write_cmd(hdc, 255 LCD_CMD_FUNCTION_SET | 256 ((hdc->ifwidth == 8) ? LCD_CMD_DATA_LEN_8BITS : 0) | 257 ((hdc->hd44780_common_flags & LCD_FLAG_F) ? 258 LCD_CMD_FONT_5X10_DOTS : 0) | 259 ((hdc->hd44780_common_flags & LCD_FLAG_N) ? 260 LCD_CMD_TWO_LINES : 0)); 261 } 262 263 int hd44780_common_fontsize(struct charlcd *lcd, enum charlcd_fontsize size) 264 { 265 struct hd44780_common *hdc = lcd->drvdata; 266 267 if (size == CHARLCD_FONTSIZE_LARGE) 268 hdc->hd44780_common_flags |= LCD_FLAG_F; 269 else 270 hdc->hd44780_common_flags &= ~LCD_FLAG_F; 271 272 hd44780_common_set_function(hdc); 273 return 0; 274 } 275 EXPORT_SYMBOL_GPL(hd44780_common_fontsize); 276 277 int hd44780_common_lines(struct charlcd *lcd, enum charlcd_lines lines) 278 { 279 struct hd44780_common *hdc = lcd->drvdata; 280 281 if (lines == CHARLCD_LINES_2) 282 hdc->hd44780_common_flags |= LCD_FLAG_N; 283 else 284 hdc->hd44780_common_flags &= ~LCD_FLAG_N; 285 286 hd44780_common_set_function(hdc); 287 return 0; 288 } 289 EXPORT_SYMBOL_GPL(hd44780_common_lines); 290 291 int hd44780_common_redefine_char(struct charlcd *lcd, char *esc) 292 { 293 /* Generator : LGcxxxxx...xx; must have <c> between '0' 294 * and '7', representing the numerical ASCII code of the 295 * redefined character, and <xx...xx> a sequence of 16 296 * hex digits representing 8 bytes for each character. 297 * Most LCDs will only use 5 lower bits of the 7 first 298 * bytes. 299 */ 300 301 struct hd44780_common *hdc = lcd->drvdata; 302 unsigned char cgbytes[8]; 303 unsigned char cgaddr; 304 int cgoffset; 305 int shift; 306 char value; 307 int addr; 308 309 if (!strchr(esc, ';')) 310 return 0; 311 312 esc++; 313 314 cgaddr = *(esc++) - '0'; 315 if (cgaddr > 7) 316 return 1; 317 318 cgoffset = 0; 319 shift = 0; 320 value = 0; 321 while (*esc && cgoffset < 8) { 322 int half; 323 324 shift ^= 4; 325 half = hex_to_bin(*esc++); 326 if (half < 0) 327 continue; 328 329 value |= half << shift; 330 if (shift == 0) { 331 cgbytes[cgoffset++] = value; 332 value = 0; 333 } 334 } 335 336 hdc->write_cmd(hdc, LCD_CMD_SET_CGRAM_ADDR | (cgaddr * 8)); 337 for (addr = 0; addr < cgoffset; addr++) 338 hdc->write_data(hdc, cgbytes[addr]); 339 340 /* ensures that we stop writing to CGRAM */ 341 lcd->ops->gotoxy(lcd, lcd->addr.x, lcd->addr.y); 342 return 1; 343 } 344 EXPORT_SYMBOL_GPL(hd44780_common_redefine_char); 345 346 struct hd44780_common *hd44780_common_alloc(void) 347 { 348 struct hd44780_common *hd; 349 350 hd = kzalloc(sizeof(*hd), GFP_KERNEL); 351 if (!hd) 352 return NULL; 353 354 hd->ifwidth = 8; 355 hd->bwidth = DEFAULT_LCD_BWIDTH; 356 hd->hwidth = DEFAULT_LCD_HWIDTH; 357 return hd; 358 } 359 EXPORT_SYMBOL_GPL(hd44780_common_alloc); 360 361 MODULE_LICENSE("GPL"); 362