drivers/auxdisplay/hd44780_common.c

   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");