drivers/staging/fbtft/fb

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This source file includes following definitions.
init_display
reset
verify_gpios
request_gpios_match
write_reg8_bus8
set_addr_win
construct_line_bitmap
iterate_diffusion_matrix
write_vmem
write
   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * FB driver for Two KS0108 LCD controllers in AGM1264K-FL display
   4  *
   5  * Copyright (C) 2014 ololoshka2871
   6  */
   7 
   8 #include <linux/module.h>
   9 #include <linux/kernel.h>
  10 #include <linux/init.h>
  11 #include <linux/gpio/consumer.h>
  12 #include <linux/delay.h>
  13 #include <linux/slab.h>
  14 
  15 #include "fbtft.h"
  16 
  17 /* Uncomment text line to use negative image on display */
  18 /*#define NEGATIVE*/
  19 
  20 #define WHITE           0xff
  21 #define BLACK           0
  22 
  23 #define DRVNAME         "fb_agm1264k-fl"
  24 #define WIDTH           64
  25 #define HEIGHT          64
  26 #define TOTALWIDTH      (WIDTH * 2)      /* because 2 x ks0108 in one display */
  27 #define FPS                     20
  28 
  29 #define EPIN            gpio.wr
  30 #define RS                      gpio.dc
  31 #define RW                      gpio.aux[2]
  32 #define CS0                     gpio.aux[0]
  33 #define CS1                     gpio.aux[1]
  34 
  35 /* diffusing error (Floyd-Steinberg) */
  36 #define DIFFUSING_MATRIX_WIDTH  2
  37 #define DIFFUSING_MATRIX_HEIGHT 2
  38 
  39 static const signed char
  40 diffusing_matrix[DIFFUSING_MATRIX_WIDTH][DIFFUSING_MATRIX_HEIGHT] = {
  41         {-1, 3},
  42         {3, 2},
  43 };
  44 
  45 static const unsigned char gamma_correction_table[] = {
  46 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1,
  47 1, 1, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 6,
  48 6, 6, 6, 7, 7, 7, 8, 8, 8, 9, 9, 9, 10, 10, 11, 11, 11, 12, 12, 13,
  49 13, 13, 14, 14, 15, 15, 16, 16, 17, 17, 18, 18, 19, 19, 20, 20, 21,
  50 22, 22, 23, 23, 24, 25, 25, 26, 26, 27, 28, 28, 29, 30, 30, 31, 32,
  51 33, 33, 34, 35, 35, 36, 37, 38, 39, 39, 40, 41, 42, 43, 43, 44, 45,
  52 46, 47, 48, 49, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61,
  53 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 73, 74, 75, 76, 77, 78, 79, 81,
  54 82, 83, 84, 85, 87, 88, 89, 90, 91, 93, 94, 95, 97, 98, 99, 100, 102,
  55 103, 105, 106, 107, 109, 110, 111, 113, 114, 116, 117, 119, 120, 121,
  56 123, 124, 126, 127, 129, 130, 132, 133, 135, 137, 138, 140, 141, 143,
  57 145, 146, 148, 149, 151, 153, 154, 156, 158, 159, 161, 163, 165, 166,
  58 168, 170, 172, 173, 175, 177, 179, 181, 182, 184, 186, 188, 190, 192,
  59 194, 196, 197, 199, 201, 203, 205, 207, 209, 211, 213, 215, 217, 219,
  60 221, 223, 225, 227, 229, 231, 234, 236, 238, 240, 242, 244, 246, 248,
  61 251, 253, 255
  62 };
  63 
  64 static int init_display(struct fbtft_par *par)
  65 {
  66         u8 i;
  67 
  68         par->fbtftops.reset(par);
  69 
  70         for (i = 0; i < 2; ++i) {
  71                 write_reg(par, i, 0x3f); /* display on */
  72                 write_reg(par, i, 0x40); /* set x to 0 */
  73                 write_reg(par, i, 0xb0); /* set page to 0 */
  74                 write_reg(par, i, 0xc0); /* set start line to 0 */
  75         }
  76 
  77         return 0;
  78 }
  79 
  80 static void reset(struct fbtft_par *par)
  81 {
  82         if (!par->gpio.reset)
  83                 return;
  84 
  85         dev_dbg(par->info->device, "%s()\n", __func__);
  86 
  87         gpiod_set_value(par->gpio.reset, 0);
  88         udelay(20);
  89         gpiod_set_value(par->gpio.reset, 1);
  90         mdelay(120);
  91 }
  92 
  93 /* Check if all necessary GPIOS defined */
  94 static int verify_gpios(struct fbtft_par *par)
  95 {
  96         int i;
  97 
  98         dev_dbg(par->info->device,
  99                 "%s()\n", __func__);
 100 
 101         if (!par->EPIN) {
 102                 dev_err(par->info->device,
 103                         "Missing info about 'wr' (aka E) gpio. Aborting.\n");
 104                 return -EINVAL;
 105         }
 106         for (i = 0; i < 8; ++i) {
 107                 if (!par->gpio.db[i]) {
 108                         dev_err(par->info->device,
 109                                 "Missing info about 'db[%i]' gpio. Aborting.\n",
 110                                 i);
 111                         return -EINVAL;
 112                 }
 113         }
 114         if (!par->CS0) {
 115                 dev_err(par->info->device,
 116                         "Missing info about 'cs0' gpio. Aborting.\n");
 117                 return -EINVAL;
 118         }
 119         if (!par->CS1) {
 120                 dev_err(par->info->device,
 121                         "Missing info about 'cs1' gpio. Aborting.\n");
 122                 return -EINVAL;
 123         }
 124         if (!par->RW) {
 125                 dev_err(par->info->device,
 126                         "Missing info about 'rw' gpio. Aborting.\n");
 127                 return -EINVAL;
 128         }
 129 
 130         return 0;
 131 }
 132 
 133 static unsigned long
 134 request_gpios_match(struct fbtft_par *par, const struct fbtft_gpio *gpio)
 135 {
 136         dev_dbg(par->info->device,
 137                 "%s('%s')\n", __func__, gpio->name);
 138 
 139         if (strcasecmp(gpio->name, "wr") == 0) {
 140                 /* left ks0108 E pin */
 141                 par->EPIN = gpio->gpio;
 142                 return GPIOD_OUT_LOW;
 143         } else if (strcasecmp(gpio->name, "cs0") == 0) {
 144                 /* left ks0108 controller pin */
 145                 par->CS0 = gpio->gpio;
 146                 return GPIOD_OUT_HIGH;
 147         } else if (strcasecmp(gpio->name, "cs1") == 0) {
 148                 /* right ks0108 controller pin */
 149                 par->CS1 = gpio->gpio;
 150                 return GPIOD_OUT_HIGH;
 151         }
 152 
 153         /* if write (rw = 0) e(1->0) perform write */
 154         /* if read (rw = 1) e(0->1) set data on D0-7*/
 155         else if (strcasecmp(gpio->name, "rw") == 0) {
 156                 par->RW = gpio->gpio;
 157                 return GPIOD_OUT_LOW;
 158         }
 159 
 160         return FBTFT_GPIO_NO_MATCH;
 161 }
 162 
 163 /* This function oses to enter commands
 164  * first byte - destination controller 0 or 1
 165  * following - commands
 166  */
 167 static void write_reg8_bus8(struct fbtft_par *par, int len, ...)
 168 {
 169         va_list args;
 170         int i, ret;
 171         u8 *buf = par->buf;
 172 
 173         if (unlikely(par->debug & DEBUG_WRITE_REGISTER)) {
 174                 va_start(args, len);
 175                 for (i = 0; i < len; i++)
 176                         buf[i] = (u8)va_arg(args, unsigned int);
 177 
 178                 va_end(args);
 179                 fbtft_par_dbg_hex(DEBUG_WRITE_REGISTER, par, par->info->device,
 180                                   u8, buf, len, "%s: ", __func__);
 181 }
 182 
 183         va_start(args, len);
 184 
 185         *buf = (u8)va_arg(args, unsigned int);
 186 
 187         if (*buf > 1) {
 188                 va_end(args);
 189                 dev_err(par->info->device,
 190                         "Incorrect chip select request (%d)\n", *buf);
 191                 return;
 192         }
 193 
 194         /* select chip */
 195         if (*buf) {
 196                 /* cs1 */
 197                 gpiod_set_value(par->CS0, 1);
 198                 gpiod_set_value(par->CS1, 0);
 199         } else {
 200                 /* cs0 */
 201                 gpiod_set_value(par->CS0, 0);
 202                 gpiod_set_value(par->CS1, 1);
 203         }
 204 
 205         gpiod_set_value(par->RS, 0); /* RS->0 (command mode) */
 206         len--;
 207 
 208         if (len) {
 209                 i = len;
 210                 while (i--)
 211                         *buf++ = (u8)va_arg(args, unsigned int);
 212                 ret = par->fbtftops.write(par, par->buf, len * (sizeof(u8)));
 213                 if (ret < 0) {
 214                         va_end(args);
 215                         dev_err(par->info->device,
 216                                 "write() failed and returned %d\n", ret);
 217                         return;
 218                 }
 219         }
 220 
 221         va_end(args);
 222 }
 223 
 224 static struct
 225 {
 226         int xs, ys_page, xe, ye_page;
 227 } addr_win;
 228 
 229 /* save display writing zone */
 230 static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
 231 {
 232         addr_win.xs = xs;
 233         addr_win.ys_page = ys / 8;
 234         addr_win.xe = xe;
 235         addr_win.ye_page = ye / 8;
 236 }
 237 
 238 static void
 239 construct_line_bitmap(struct fbtft_par *par, u8 *dest, signed short *src,
 240                       int xs, int xe, int y)
 241 {
 242         int x, i;
 243 
 244         for (x = xs; x < xe; ++x) {
 245                 u8 res = 0;
 246 
 247                 for (i = 0; i < 8; i++)
 248                         if (src[(y * 8 + i) * par->info->var.xres + x])
 249                                 res |= 1 << i;
 250 #ifdef NEGATIVE
 251                 *dest++ = res;
 252 #else
 253                 *dest++ = ~res;
 254 #endif
 255         }
 256 }
 257 
 258 static void iterate_diffusion_matrix(u32 xres, u32 yres, int x,
 259                                      int y, signed short *convert_buf,
 260                                      signed short pixel, signed short error)
 261 {
 262         u16 i, j;
 263 
 264         /* diffusion matrix row */
 265         for (i = 0; i < DIFFUSING_MATRIX_WIDTH; ++i)
 266                 /* diffusion matrix column */
 267                 for (j = 0; j < DIFFUSING_MATRIX_HEIGHT; ++j) {
 268                         signed short *write_pos;
 269                         signed char coeff;
 270 
 271                         /* skip pixels out of zone */
 272                         if (x + i < 0 || x + i >= xres || y + j >= yres)
 273                                 continue;
 274                         write_pos = &convert_buf[(y + j) * xres + x + i];
 275                         coeff = diffusing_matrix[i][j];
 276                         if (-1 == coeff) {
 277                                 /* pixel itself */
 278                                 *write_pos = pixel;
 279                         } else {
 280                                 signed short p = *write_pos + error * coeff;
 281 
 282                                 if (p > WHITE)
 283                                         p = WHITE;
 284                                 if (p < BLACK)
 285                                         p = BLACK;
 286                                 *write_pos = p;
 287                         }
 288                 }
 289 }
 290 
 291 static int write_vmem(struct fbtft_par *par, size_t offset, size_t len)
 292 {
 293         u16 *vmem16 = (u16 *)par->info->screen_buffer;
 294         u8 *buf = par->txbuf.buf;
 295         int x, y;
 296         int ret = 0;
 297 
 298         /* buffer to convert RGB565 -> grayscale16 -> Dithered image 1bpp */
 299         signed short *convert_buf = kmalloc_array(par->info->var.xres *
 300                 par->info->var.yres, sizeof(signed short), GFP_NOIO);
 301 
 302         if (!convert_buf)
 303                 return -ENOMEM;
 304 
 305         /* converting to grayscale16 */
 306         for (x = 0; x < par->info->var.xres; ++x)
 307                 for (y = 0; y < par->info->var.yres; ++y) {
 308                         u16 pixel = vmem16[y *  par->info->var.xres + x];
 309                         u16 b = pixel & 0x1f;
 310                         u16 g = (pixel & (0x3f << 5)) >> 5;
 311                         u16 r = (pixel & (0x1f << (5 + 6))) >> (5 + 6);
 312 
 313                         pixel = (299 * r + 587 * g + 114 * b) / 200;
 314                         if (pixel > 255)
 315                                 pixel = 255;
 316 
 317                         /* gamma-correction by table */
 318                         convert_buf[y *  par->info->var.xres + x] =
 319                                 (signed short)gamma_correction_table[pixel];
 320                 }
 321 
 322         /* Image Dithering */
 323         for (x = 0; x < par->info->var.xres; ++x)
 324                 for (y = 0; y < par->info->var.yres; ++y) {
 325                         signed short pixel =
 326                                 convert_buf[y *  par->info->var.xres + x];
 327                         signed short error_b = pixel - BLACK;
 328                         signed short error_w = pixel - WHITE;
 329                         signed short error;
 330 
 331                         /* what color close? */
 332                         if (abs(error_b) >= abs(error_w)) {
 333                                 /* white */
 334                                 error = error_w;
 335                                 pixel = 0xff;
 336                         } else {
 337                                 /* black */
 338                                 error = error_b;
 339                                 pixel = 0;
 340                         }
 341 
 342                         error /= 8;
 343 
 344                         iterate_diffusion_matrix(par->info->var.xres,
 345                                                  par->info->var.yres,
 346                                                  x, y, convert_buf,
 347                                                  pixel, error);
 348                 }
 349 
 350         /* 1 string = 2 pages */
 351         for (y = addr_win.ys_page; y <= addr_win.ye_page; ++y) {
 352                 /* left half of display */
 353                 if (addr_win.xs < par->info->var.xres / 2) {
 354                         construct_line_bitmap(par, buf, convert_buf,
 355                                               addr_win.xs,
 356                                               par->info->var.xres / 2, y);
 357 
 358                         len = par->info->var.xres / 2 - addr_win.xs;
 359 
 360                         /* select left side (sc0)
 361                          * set addr
 362                          */
 363                         write_reg(par, 0x00, BIT(6) | (u8)addr_win.xs);
 364                         write_reg(par, 0x00, (0x17 << 3) | (u8)y);
 365 
 366                         /* write bitmap */
 367                         gpiod_set_value(par->RS, 1); /* RS->1 (data mode) */
 368                         ret = par->fbtftops.write(par, buf, len);
 369                         if (ret < 0)
 370                                 dev_err(par->info->device,
 371                                         "write failed and returned: %d\n",
 372                                         ret);
 373                 }
 374                 /* right half of display */
 375                 if (addr_win.xe >= par->info->var.xres / 2) {
 376                         construct_line_bitmap(par, buf,
 377                                               convert_buf,
 378                                               par->info->var.xres / 2,
 379                                               addr_win.xe + 1, y);
 380 
 381                         len = addr_win.xe + 1 - par->info->var.xres / 2;
 382 
 383                         /* select right side (sc1)
 384                          * set addr
 385                          */
 386                         write_reg(par, 0x01, BIT(6));
 387                         write_reg(par, 0x01, (0x17 << 3) | (u8)y);
 388 
 389                         /* write bitmap */
 390                         gpiod_set_value(par->RS, 1); /* RS->1 (data mode) */
 391                         par->fbtftops.write(par, buf, len);
 392                         if (ret < 0)
 393                                 dev_err(par->info->device,
 394                                         "write failed and returned: %d\n",
 395                                         ret);
 396                 }
 397         }
 398         kfree(convert_buf);
 399 
 400         gpiod_set_value(par->CS0, 1);
 401         gpiod_set_value(par->CS1, 1);
 402 
 403         return ret;
 404 }
 405 
 406 static int write(struct fbtft_par *par, void *buf, size_t len)
 407 {
 408         fbtft_par_dbg_hex(DEBUG_WRITE, par, par->info->device, u8, buf, len,
 409                           "%s(len=%zu): ", __func__, len);
 410 
 411         gpiod_set_value(par->RW, 0); /* set write mode */
 412 
 413         while (len--) {
 414                 u8 i, data;
 415 
 416                 data = *(u8 *)buf++;
 417 
 418                 /* set data bus */
 419                 for (i = 0; i < 8; ++i)
 420                         gpiod_set_value(par->gpio.db[i], data & (1 << i));
 421                 /* set E */
 422                 gpiod_set_value(par->EPIN, 1);
 423                 udelay(5);
 424                 /* unset E - write */
 425                 gpiod_set_value(par->EPIN, 0);
 426                 udelay(1);
 427         }
 428 
 429         return 0;
 430 }
 431 
 432 static struct fbtft_display display = {
 433         .regwidth = 8,
 434         .width = TOTALWIDTH,
 435         .height = HEIGHT,
 436         .fps = FPS,
 437         .fbtftops = {
 438                 .init_display = init_display,
 439                 .set_addr_win = set_addr_win,
 440                 .verify_gpios = verify_gpios,
 441                 .request_gpios_match = request_gpios_match,
 442                 .reset = reset,
 443                 .write = write,
 444                 .write_register = write_reg8_bus8,
 445                 .write_vmem = write_vmem,
 446         },
 447 };
 448 
 449 FBTFT_REGISTER_DRIVER(DRVNAME, "displaytronic,fb_agm1264k-fl", &display);
 450 
 451 MODULE_ALIAS("platform:" DRVNAME);
 452 
 453 MODULE_DESCRIPTION("Two KS0108 LCD controllers in AGM1264K-FL display");
 454 MODULE_AUTHOR("ololoshka2871");
 455 MODULE_LICENSE("GPL");
/* [<][>][^][v][top][bottom][index][help] */
root/drivers/staging/fbtft/fb_agm1264k-fl.c

DEFINITIONS
