drivers/auxdisplay/lcd2s.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  console driver for LCD2S 4x20 character displays connected through i2c.
   4  *  The display also has a spi interface, but the driver does not support
   5  *  this yet.
   6  *
   7  *  This is a driver allowing you to use a LCD2S 4x20 from modtronix
   8  *  engineering as auxdisplay character device.
   9  *
  10  *  (C) 2019 by Lemonage Software GmbH
  11  *  Author: Lars Pöschel <poeschel@lemonage.de>
  12  *  All rights reserved.
  13  */
  14 #include <linux/kernel.h>
  15 #include <linux/module.h>
  16 #include <linux/slab.h>
  17 #include <linux/i2c.h>
  18 #include <linux/delay.h>
  19
  20 #include "charlcd.h"
  21
  22 #define LCD2S_CMD_CUR_MOVES_FWD         0x09
  23 #define LCD2S_CMD_CUR_BLINK_OFF         0x10
  24 #define LCD2S_CMD_CUR_UL_OFF            0x11
  25 #define LCD2S_CMD_DISPLAY_OFF           0x12
  26 #define LCD2S_CMD_CUR_BLINK_ON          0x18
  27 #define LCD2S_CMD_CUR_UL_ON             0x19
  28 #define LCD2S_CMD_DISPLAY_ON            0x1a
  29 #define LCD2S_CMD_BACKLIGHT_OFF         0x20
  30 #define LCD2S_CMD_BACKLIGHT_ON          0x28
  31 #define LCD2S_CMD_WRITE                 0x80
  32 #define LCD2S_CMD_MOV_CUR_RIGHT         0x83
  33 #define LCD2S_CMD_MOV_CUR_LEFT          0x84
  34 #define LCD2S_CMD_SHIFT_RIGHT           0x85
  35 #define LCD2S_CMD_SHIFT_LEFT            0x86
  36 #define LCD2S_CMD_SHIFT_UP              0x87
  37 #define LCD2S_CMD_SHIFT_DOWN            0x88
  38 #define LCD2S_CMD_CUR_ADDR              0x89
  39 #define LCD2S_CMD_CUR_POS               0x8a
  40 #define LCD2S_CMD_CUR_RESET             0x8b
  41 #define LCD2S_CMD_CLEAR                 0x8c
  42 #define LCD2S_CMD_DEF_CUSTOM_CHAR       0x92
  43 #define LCD2S_CMD_READ_STATUS           0xd0
  44
  45 #define LCD2S_CHARACTER_SIZE            8
  46
  47 #define LCD2S_STATUS_BUF_MASK           0x7f
  48
  49 struct lcd2s_data {
  50         struct i2c_client *i2c;
  51         struct charlcd *charlcd;
  52 };
  53
  54 static s32 lcd2s_wait_buf_free(const struct i2c_client *client, int count)
  55 {
  56         s32 status;
  57
  58         status = i2c_smbus_read_byte_data(client, LCD2S_CMD_READ_STATUS);
  59         if (status < 0)
  60                 return status;
  61
  62         while ((status & LCD2S_STATUS_BUF_MASK) < count) {
  63                 mdelay(1);
  64                 status = i2c_smbus_read_byte_data(client,
  65                                                   LCD2S_CMD_READ_STATUS);
  66                 if (status < 0)
  67                         return status;
  68         }
  69         return 0;
  70 }
  71
  72 static int lcd2s_i2c_master_send(const struct i2c_client *client,
  73                                  const char *buf, int count)
  74 {
  75         s32 status;
  76
  77         status = lcd2s_wait_buf_free(client, count);
  78         if (status < 0)
  79                 return status;
  80
  81         return i2c_master_send(client, buf, count);
  82 }
  83
  84 static int lcd2s_i2c_smbus_write_byte(const struct i2c_client *client, u8 value)
  85 {
  86         s32 status;
  87
  88         status = lcd2s_wait_buf_free(client, 1);
  89         if (status < 0)
  90                 return status;
  91
  92         return i2c_smbus_write_byte(client, value);
  93 }
  94
  95 static int lcd2s_print(struct charlcd *lcd, int c)
  96 {
  97         struct lcd2s_data *lcd2s = lcd->drvdata;
  98         u8 buf[2] = { LCD2S_CMD_WRITE, c };
  99
 100         lcd2s_i2c_master_send(lcd2s->i2c, buf, sizeof(buf));
 101         return 0;
 102 }
 103
 104 static int lcd2s_gotoxy(struct charlcd *lcd, unsigned int x, unsigned int y)
 105 {
 106         struct lcd2s_data *lcd2s = lcd->drvdata;
 107         u8 buf[] = { LCD2S_CMD_CUR_POS, y + 1, x + 1};
 108
 109         lcd2s_i2c_master_send(lcd2s->i2c, buf, sizeof(buf));
 110
 111         return 0;
 112 }
 113
 114 static int lcd2s_home(struct charlcd *lcd)
 115 {
 116         struct lcd2s_data *lcd2s = lcd->drvdata;
 117
 118         lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_RESET);
 119         return 0;
 120 }
 121
 122 static int lcd2s_init_display(struct charlcd *lcd)
 123 {
 124         struct lcd2s_data *lcd2s = lcd->drvdata;
 125
 126         /* turn everything off, but display on */
 127         lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_DISPLAY_ON);
 128         lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_BACKLIGHT_OFF);
 129         lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_MOVES_FWD);
 130         lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_BLINK_OFF);
 131         lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_UL_OFF);
 132         lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CLEAR);
 133
 134         return 0;
 135 }
 136
 137 static int lcd2s_shift_cursor(struct charlcd *lcd, enum charlcd_shift_dir dir)
 138 {
 139         struct lcd2s_data *lcd2s = lcd->drvdata;
 140
 141         if (dir == CHARLCD_SHIFT_LEFT)
 142                 lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_MOV_CUR_LEFT);
 143         else
 144                 lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_MOV_CUR_RIGHT);
 145
 146         return 0;
 147 }
 148
 149 static int lcd2s_shift_display(struct charlcd *lcd, enum charlcd_shift_dir dir)
 150 {
 151         struct lcd2s_data *lcd2s = lcd->drvdata;
 152
 153         if (dir == CHARLCD_SHIFT_LEFT)
 154                 lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_SHIFT_LEFT);
 155         else
 156                 lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_SHIFT_RIGHT);
 157
 158         return 0;
 159 }
 160
 161 static void lcd2s_backlight(struct charlcd *lcd, enum charlcd_onoff on)
 162 {
 163         struct lcd2s_data *lcd2s = lcd->drvdata;
 164
 165         if (on)
 166                 lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_BACKLIGHT_ON);
 167         else
 168                 lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_BACKLIGHT_OFF);
 169 }
 170
 171 static int lcd2s_display(struct charlcd *lcd, enum charlcd_onoff on)
 172 {
 173         struct lcd2s_data *lcd2s = lcd->drvdata;
 174
 175         if (on)
 176                 lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_DISPLAY_ON);
 177         else
 178                 lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_DISPLAY_OFF);
 179
 180         return 0;
 181 }
 182
 183 static int lcd2s_cursor(struct charlcd *lcd, enum charlcd_onoff on)
 184 {
 185         struct lcd2s_data *lcd2s = lcd->drvdata;
 186
 187         if (on)
 188                 lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_UL_ON);
 189         else
 190                 lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_UL_OFF);
 191
 192         return 0;
 193 }
 194
 195 static int lcd2s_blink(struct charlcd *lcd, enum charlcd_onoff on)
 196 {
 197         struct lcd2s_data *lcd2s = lcd->drvdata;
 198
 199         if (on)
 200                 lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_BLINK_ON);
 201         else
 202                 lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_BLINK_OFF);
 203
 204         return 0;
 205 }
 206
 207 static int lcd2s_fontsize(struct charlcd *lcd, enum charlcd_fontsize size)
 208 {
 209         return 0;
 210 }
 211
 212 static int lcd2s_lines(struct charlcd *lcd, enum charlcd_lines lines)
 213 {
 214         return 0;
 215 }
 216
 217 static int lcd2s_redefine_char(struct charlcd *lcd, char *esc)
 218 {
 219         /* Generator : LGcxxxxx...xx; must have <c> between '0'
 220          * and '7', representing the numerical ASCII code of the
 221          * redefined character, and <xx...xx> a sequence of 16
 222          * hex digits representing 8 bytes for each character.
 223          * Most LCDs will only use 5 lower bits of the 7 first
 224          * bytes.
 225          */
 226
 227         struct lcd2s_data *lcd2s = lcd->drvdata;
 228         u8 buf[LCD2S_CHARACTER_SIZE + 2] = { LCD2S_CMD_DEF_CUSTOM_CHAR };
 229         u8 value;
 230         int shift, i;
 231
 232         if (!strchr(esc, ';'))
 233                 return 0;
 234
 235         esc++;
 236
 237         buf[1] = *(esc++) - '0';
 238         if (buf[1] > 7)
 239                 return 1;
 240
 241         i = 0;
 242         shift = 0;
 243         value = 0;
 244         while (*esc && i < LCD2S_CHARACTER_SIZE + 2) {
 245                 int half;
 246
 247                 shift ^= 4;
 248                 half = hex_to_bin(*esc++);
 249                 if (half < 0)
 250                         continue;
 251
 252                 value |= half << shift;
 253                 if (shift == 0) {
 254                         buf[i++] = value;
 255                         value = 0;
 256                 }
 257         }
 258
 259         lcd2s_i2c_master_send(lcd2s->i2c, buf, sizeof(buf));
 260         return 1;
 261 }
 262
 263 static int lcd2s_clear_display(struct charlcd *lcd)
 264 {
 265         struct lcd2s_data *lcd2s = lcd->drvdata;
 266
 267         /* This implicitly sets cursor to first row and column */
 268         lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CLEAR);
 269         return 0;
 270 }
 271
 272 static const struct charlcd_ops lcd2s_ops = {
 273         .print          = lcd2s_print,
 274         .backlight      = lcd2s_backlight,
 275         .gotoxy         = lcd2s_gotoxy,
 276         .home           = lcd2s_home,
 277         .clear_display  = lcd2s_clear_display,
 278         .init_display   = lcd2s_init_display,
 279         .shift_cursor   = lcd2s_shift_cursor,
 280         .shift_display  = lcd2s_shift_display,
 281         .display        = lcd2s_display,
 282         .cursor         = lcd2s_cursor,
 283         .blink          = lcd2s_blink,
 284         .fontsize       = lcd2s_fontsize,
 285         .lines          = lcd2s_lines,
 286         .redefine_char  = lcd2s_redefine_char,
 287 };
 288
 289 static int lcd2s_i2c_probe(struct i2c_client *i2c,
 290                                 const struct i2c_device_id *id)
 291 {
 292         struct charlcd *lcd;
 293         struct lcd2s_data *lcd2s;
 294         int err;
 295
 296         if (!i2c_check_functionality(i2c->adapter,
 297                         I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
 298                         I2C_FUNC_SMBUS_WRITE_BLOCK_DATA))
 299                 return -EIO;
 300
 301         /* Test, if the display is responding */
 302         err = lcd2s_i2c_smbus_write_byte(i2c, LCD2S_CMD_DISPLAY_OFF);
 303         if (err < 0)
 304                 return err;
 305
 306         lcd = charlcd_alloc();
 307         if (!lcd)
 308                 return -ENOMEM;
 309
 310         lcd2s = kzalloc(sizeof(struct lcd2s_data), GFP_KERNEL);
 311         if (!lcd2s) {
 312                 err = -ENOMEM;
 313                 goto fail1;
 314         }
 315
 316         lcd->drvdata = lcd2s;
 317         lcd2s->i2c = i2c;
 318         lcd2s->charlcd = lcd;
 319
 320         /* Required properties */
 321         err = device_property_read_u32(&i2c->dev, "display-height-chars",
 322                         &lcd->height);
 323         if (err)
 324                 goto fail2;
 325
 326         err = device_property_read_u32(&i2c->dev, "display-width-chars",
 327                         &lcd->width);
 328         if (err)
 329                 goto fail2;
 330
 331         lcd->ops = &lcd2s_ops;
 332
 333         err = charlcd_register(lcd2s->charlcd);
 334         if (err)
 335                 goto fail2;
 336
 337         i2c_set_clientdata(i2c, lcd2s);
 338         return 0;
 339
 340 fail2:
 341         kfree(lcd2s);
 342 fail1:
 343         kfree(lcd);
 344         return err;
 345 }
 346
 347 static int lcd2s_i2c_remove(struct i2c_client *i2c)
 348 {
 349         struct lcd2s_data *lcd2s = i2c_get_clientdata(i2c);
 350
 351         charlcd_unregister(lcd2s->charlcd);
 352         kfree(lcd2s->charlcd);
 353         return 0;
 354 }
 355
 356 static const struct i2c_device_id lcd2s_i2c_id[] = {
 357         { "lcd2s", 0 },
 358         { }
 359 };
 360 MODULE_DEVICE_TABLE(i2c, lcd2s_i2c_id);
 361
 362 #ifdef CONFIG_OF
 363 static const struct of_device_id lcd2s_of_table[] = {
 364         { .compatible = "modtronix,lcd2s" },
 365         { }
 366 };
 367 MODULE_DEVICE_TABLE(of, lcd2s_of_table);
 368 #endif
 369
 370 static struct i2c_driver lcd2s_i2c_driver = {
 371         .driver = {
 372                 .name = "lcd2s",
 373 #ifdef CONFIG_OF
 374                 .of_match_table = of_match_ptr(lcd2s_of_table),
 375 #endif
 376         },
 377         .probe = lcd2s_i2c_probe,
 378         .remove = lcd2s_i2c_remove,
 379         .id_table = lcd2s_i2c_id,
 380 };
 381
 382 static int __init lcd2s_modinit(void)
 383 {
 384         int ret = 0;
 385
 386         ret = i2c_add_driver(&lcd2s_i2c_driver);
 387         if (ret != 0)
 388                 pr_err("Failed to register lcd2s driver\n");
 389
 390         return ret;
 391 }
 392 module_init(lcd2s_modinit)
 393
 394 static void __exit lcd2s_exit(void)
 395 {
 396         i2c_del_driver(&lcd2s_i2c_driver);
 397 }
 398 module_exit(lcd2s_exit)
 399
 400 MODULE_DESCRIPTION("LCD2S character display driver");
 401 MODULE_AUTHOR("Lars Poeschel");
 402 MODULE_LICENSE("GPL");