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