1 /* 2 * Driver for the Solomon SSD1307 OLED controller 3 * 4 * Copyright 2012 Free Electrons 5 * 6 * Licensed under the GPLv2 or later. 7 */ 8 9 #include <linux/module.h> 10 #include <linux/kernel.h> 11 #include <linux/i2c.h> 12 #include <linux/fb.h> 13 #include <linux/uaccess.h> 14 #include <linux/of_device.h> 15 #include <linux/of_gpio.h> 16 #include <linux/pwm.h> 17 #include <linux/delay.h> 18 19 #define SSD1307FB_DATA 0x40 20 #define SSD1307FB_COMMAND 0x80 21 22 #define SSD1307FB_SET_ADDRESS_MODE 0x20 23 #define SSD1307FB_SET_ADDRESS_MODE_HORIZONTAL (0x00) 24 #define SSD1307FB_SET_ADDRESS_MODE_VERTICAL (0x01) 25 #define SSD1307FB_SET_ADDRESS_MODE_PAGE (0x02) 26 #define SSD1307FB_SET_COL_RANGE 0x21 27 #define SSD1307FB_SET_PAGE_RANGE 0x22 28 #define SSD1307FB_CONTRAST 0x81 29 #define SSD1307FB_CHARGE_PUMP 0x8d 30 #define SSD1307FB_SEG_REMAP_ON 0xa1 31 #define SSD1307FB_DISPLAY_OFF 0xae 32 #define SSD1307FB_SET_MULTIPLEX_RATIO 0xa8 33 #define SSD1307FB_DISPLAY_ON 0xaf 34 #define SSD1307FB_START_PAGE_ADDRESS 0xb0 35 #define SSD1307FB_SET_DISPLAY_OFFSET 0xd3 36 #define SSD1307FB_SET_CLOCK_FREQ 0xd5 37 #define SSD1307FB_SET_PRECHARGE_PERIOD 0xd9 38 #define SSD1307FB_SET_COM_PINS_CONFIG 0xda 39 #define SSD1307FB_SET_VCOMH 0xdb 40 41 struct ssd1307fb_par; 42 43 struct ssd1307fb_ops { 44 int (*init)(struct ssd1307fb_par *); 45 int (*remove)(struct ssd1307fb_par *); 46 }; 47 48 struct ssd1307fb_par { 49 struct i2c_client *client; 50 u32 height; 51 struct fb_info *info; 52 struct ssd1307fb_ops *ops; 53 u32 page_offset; 54 struct pwm_device *pwm; 55 u32 pwm_period; 56 int reset; 57 u32 width; 58 }; 59 60 struct ssd1307fb_array { 61 u8 type; 62 u8 data[0]; 63 }; 64 65 static struct fb_fix_screeninfo ssd1307fb_fix = { 66 .id = "Solomon SSD1307", 67 .type = FB_TYPE_PACKED_PIXELS, 68 .visual = FB_VISUAL_MONO10, 69 .xpanstep = 0, 70 .ypanstep = 0, 71 .ywrapstep = 0, 72 .accel = FB_ACCEL_NONE, 73 }; 74 75 static struct fb_var_screeninfo ssd1307fb_var = { 76 .bits_per_pixel = 1, 77 }; 78 79 static struct ssd1307fb_array *ssd1307fb_alloc_array(u32 len, u8 type) 80 { 81 struct ssd1307fb_array *array; 82 83 array = kzalloc(sizeof(struct ssd1307fb_array) + len, GFP_KERNEL); 84 if (!array) 85 return NULL; 86 87 array->type = type; 88 89 return array; 90 } 91 92 static int ssd1307fb_write_array(struct i2c_client *client, 93 struct ssd1307fb_array *array, u32 len) 94 { 95 int ret; 96 97 len += sizeof(struct ssd1307fb_array); 98 99 ret = i2c_master_send(client, (u8 *)array, len); 100 if (ret != len) { 101 dev_err(&client->dev, "Couldn't send I2C command.\n"); 102 return ret; 103 } 104 105 return 0; 106 } 107 108 static inline int ssd1307fb_write_cmd(struct i2c_client *client, u8 cmd) 109 { 110 struct ssd1307fb_array *array; 111 int ret; 112 113 array = ssd1307fb_alloc_array(1, SSD1307FB_COMMAND); 114 if (!array) 115 return -ENOMEM; 116 117 array->data[0] = cmd; 118 119 ret = ssd1307fb_write_array(client, array, 1); 120 kfree(array); 121 122 return ret; 123 } 124 125 static inline int ssd1307fb_write_data(struct i2c_client *client, u8 data) 126 { 127 struct ssd1307fb_array *array; 128 int ret; 129 130 array = ssd1307fb_alloc_array(1, SSD1307FB_DATA); 131 if (!array) 132 return -ENOMEM; 133 134 array->data[0] = data; 135 136 ret = ssd1307fb_write_array(client, array, 1); 137 kfree(array); 138 139 return ret; 140 } 141 142 static void ssd1307fb_update_display(struct ssd1307fb_par *par) 143 { 144 struct ssd1307fb_array *array; 145 u8 *vmem = par->info->screen_base; 146 int i, j, k; 147 148 array = ssd1307fb_alloc_array(par->width * par->height / 8, 149 SSD1307FB_DATA); 150 if (!array) 151 return; 152 153 /* 154 * The screen is divided in pages, each having a height of 8 155 * pixels, and the width of the screen. When sending a byte of 156 * data to the controller, it gives the 8 bits for the current 157 * column. I.e, the first byte are the 8 bits of the first 158 * column, then the 8 bits for the second column, etc. 159 * 160 * 161 * Representation of the screen, assuming it is 5 bits 162 * wide. Each letter-number combination is a bit that controls 163 * one pixel. 164 * 165 * A0 A1 A2 A3 A4 166 * B0 B1 B2 B3 B4 167 * C0 C1 C2 C3 C4 168 * D0 D1 D2 D3 D4 169 * E0 E1 E2 E3 E4 170 * F0 F1 F2 F3 F4 171 * G0 G1 G2 G3 G4 172 * H0 H1 H2 H3 H4 173 * 174 * If you want to update this screen, you need to send 5 bytes: 175 * (1) A0 B0 C0 D0 E0 F0 G0 H0 176 * (2) A1 B1 C1 D1 E1 F1 G1 H1 177 * (3) A2 B2 C2 D2 E2 F2 G2 H2 178 * (4) A3 B3 C3 D3 E3 F3 G3 H3 179 * (5) A4 B4 C4 D4 E4 F4 G4 H4 180 */ 181 182 for (i = 0; i < (par->height / 8); i++) { 183 for (j = 0; j < par->width; j++) { 184 u32 array_idx = i * par->width + j; 185 array->data[array_idx] = 0; 186 for (k = 0; k < 8; k++) { 187 u32 page_length = par->width * i; 188 u32 index = page_length + (par->width * k + j) / 8; 189 u8 byte = *(vmem + index); 190 u8 bit = byte & (1 << (j % 8)); 191 bit = bit >> (j % 8); 192 array->data[array_idx] |= bit << k; 193 } 194 } 195 } 196 197 ssd1307fb_write_array(par->client, array, par->width * par->height / 8); 198 kfree(array); 199 } 200 201 202 static ssize_t ssd1307fb_write(struct fb_info *info, const char __user *buf, 203 size_t count, loff_t *ppos) 204 { 205 struct ssd1307fb_par *par = info->par; 206 unsigned long total_size; 207 unsigned long p = *ppos; 208 u8 __iomem *dst; 209 210 total_size = info->fix.smem_len; 211 212 if (p > total_size) 213 return -EINVAL; 214 215 if (count + p > total_size) 216 count = total_size - p; 217 218 if (!count) 219 return -EINVAL; 220 221 dst = (void __force *) (info->screen_base + p); 222 223 if (copy_from_user(dst, buf, count)) 224 return -EFAULT; 225 226 ssd1307fb_update_display(par); 227 228 *ppos += count; 229 230 return count; 231 } 232 233 static void ssd1307fb_fillrect(struct fb_info *info, const struct fb_fillrect *rect) 234 { 235 struct ssd1307fb_par *par = info->par; 236 sys_fillrect(info, rect); 237 ssd1307fb_update_display(par); 238 } 239 240 static void ssd1307fb_copyarea(struct fb_info *info, const struct fb_copyarea *area) 241 { 242 struct ssd1307fb_par *par = info->par; 243 sys_copyarea(info, area); 244 ssd1307fb_update_display(par); 245 } 246 247 static void ssd1307fb_imageblit(struct fb_info *info, const struct fb_image *image) 248 { 249 struct ssd1307fb_par *par = info->par; 250 sys_imageblit(info, image); 251 ssd1307fb_update_display(par); 252 } 253 254 static struct fb_ops ssd1307fb_ops = { 255 .owner = THIS_MODULE, 256 .fb_read = fb_sys_read, 257 .fb_write = ssd1307fb_write, 258 .fb_fillrect = ssd1307fb_fillrect, 259 .fb_copyarea = ssd1307fb_copyarea, 260 .fb_imageblit = ssd1307fb_imageblit, 261 }; 262 263 static void ssd1307fb_deferred_io(struct fb_info *info, 264 struct list_head *pagelist) 265 { 266 ssd1307fb_update_display(info->par); 267 } 268 269 static struct fb_deferred_io ssd1307fb_defio = { 270 .delay = HZ, 271 .deferred_io = ssd1307fb_deferred_io, 272 }; 273 274 static int ssd1307fb_ssd1307_init(struct ssd1307fb_par *par) 275 { 276 int ret; 277 278 par->pwm = pwm_get(&par->client->dev, NULL); 279 if (IS_ERR(par->pwm)) { 280 dev_err(&par->client->dev, "Could not get PWM from device tree!\n"); 281 return PTR_ERR(par->pwm); 282 } 283 284 par->pwm_period = pwm_get_period(par->pwm); 285 /* Enable the PWM */ 286 pwm_config(par->pwm, par->pwm_period / 2, par->pwm_period); 287 pwm_enable(par->pwm); 288 289 dev_dbg(&par->client->dev, "Using PWM%d with a %dns period.\n", 290 par->pwm->pwm, par->pwm_period); 291 292 /* Map column 127 of the OLED to segment 0 */ 293 ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SEG_REMAP_ON); 294 if (ret < 0) 295 return ret; 296 297 /* Turn on the display */ 298 ret = ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_ON); 299 if (ret < 0) 300 return ret; 301 302 return 0; 303 } 304 305 static int ssd1307fb_ssd1307_remove(struct ssd1307fb_par *par) 306 { 307 pwm_disable(par->pwm); 308 pwm_put(par->pwm); 309 return 0; 310 } 311 312 static struct ssd1307fb_ops ssd1307fb_ssd1307_ops = { 313 .init = ssd1307fb_ssd1307_init, 314 .remove = ssd1307fb_ssd1307_remove, 315 }; 316 317 static int ssd1307fb_ssd1306_init(struct ssd1307fb_par *par) 318 { 319 int ret; 320 321 /* Set initial contrast */ 322 ret = ssd1307fb_write_cmd(par->client, SSD1307FB_CONTRAST); 323 ret = ret & ssd1307fb_write_cmd(par->client, 0x7f); 324 if (ret < 0) 325 return ret; 326 327 /* Set COM direction */ 328 ret = ssd1307fb_write_cmd(par->client, 0xc8); 329 if (ret < 0) 330 return ret; 331 332 /* Set segment re-map */ 333 ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SEG_REMAP_ON); 334 if (ret < 0) 335 return ret; 336 337 /* Set multiplex ratio value */ 338 ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_MULTIPLEX_RATIO); 339 ret = ret & ssd1307fb_write_cmd(par->client, par->height - 1); 340 if (ret < 0) 341 return ret; 342 343 /* set display offset value */ 344 ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_DISPLAY_OFFSET); 345 ret = ssd1307fb_write_cmd(par->client, 0x20); 346 if (ret < 0) 347 return ret; 348 349 /* Set clock frequency */ 350 ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_CLOCK_FREQ); 351 ret = ret & ssd1307fb_write_cmd(par->client, 0xf0); 352 if (ret < 0) 353 return ret; 354 355 /* Set precharge period in number of ticks from the internal clock */ 356 ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_PRECHARGE_PERIOD); 357 ret = ret & ssd1307fb_write_cmd(par->client, 0x22); 358 if (ret < 0) 359 return ret; 360 361 /* Set COM pins configuration */ 362 ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_COM_PINS_CONFIG); 363 ret = ret & ssd1307fb_write_cmd(par->client, 0x22); 364 if (ret < 0) 365 return ret; 366 367 /* Set VCOMH */ 368 ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_VCOMH); 369 ret = ret & ssd1307fb_write_cmd(par->client, 0x49); 370 if (ret < 0) 371 return ret; 372 373 /* Turn on the DC-DC Charge Pump */ 374 ret = ssd1307fb_write_cmd(par->client, SSD1307FB_CHARGE_PUMP); 375 ret = ret & ssd1307fb_write_cmd(par->client, 0x14); 376 if (ret < 0) 377 return ret; 378 379 /* Switch to horizontal addressing mode */ 380 ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_ADDRESS_MODE); 381 ret = ret & ssd1307fb_write_cmd(par->client, 382 SSD1307FB_SET_ADDRESS_MODE_HORIZONTAL); 383 if (ret < 0) 384 return ret; 385 386 ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_COL_RANGE); 387 ret = ret & ssd1307fb_write_cmd(par->client, 0x0); 388 ret = ret & ssd1307fb_write_cmd(par->client, par->width - 1); 389 if (ret < 0) 390 return ret; 391 392 ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_PAGE_RANGE); 393 ret = ret & ssd1307fb_write_cmd(par->client, 0x0); 394 ret = ret & ssd1307fb_write_cmd(par->client, 395 par->page_offset + (par->height / 8) - 1); 396 if (ret < 0) 397 return ret; 398 399 /* Turn on the display */ 400 ret = ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_ON); 401 if (ret < 0) 402 return ret; 403 404 return 0; 405 } 406 407 static struct ssd1307fb_ops ssd1307fb_ssd1306_ops = { 408 .init = ssd1307fb_ssd1306_init, 409 }; 410 411 static const struct of_device_id ssd1307fb_of_match[] = { 412 { 413 .compatible = "solomon,ssd1306fb-i2c", 414 .data = (void *)&ssd1307fb_ssd1306_ops, 415 }, 416 { 417 .compatible = "solomon,ssd1307fb-i2c", 418 .data = (void *)&ssd1307fb_ssd1307_ops, 419 }, 420 {}, 421 }; 422 MODULE_DEVICE_TABLE(of, ssd1307fb_of_match); 423 424 static int ssd1307fb_probe(struct i2c_client *client, 425 const struct i2c_device_id *id) 426 { 427 struct fb_info *info; 428 struct device_node *node = client->dev.of_node; 429 u32 vmem_size; 430 struct ssd1307fb_par *par; 431 u8 *vmem; 432 int ret; 433 434 if (!node) { 435 dev_err(&client->dev, "No device tree data found!\n"); 436 return -EINVAL; 437 } 438 439 info = framebuffer_alloc(sizeof(struct ssd1307fb_par), &client->dev); 440 if (!info) { 441 dev_err(&client->dev, "Couldn't allocate framebuffer.\n"); 442 return -ENOMEM; 443 } 444 445 par = info->par; 446 par->info = info; 447 par->client = client; 448 449 par->ops = (struct ssd1307fb_ops *)of_match_device(ssd1307fb_of_match, 450 &client->dev)->data; 451 452 par->reset = of_get_named_gpio(client->dev.of_node, 453 "reset-gpios", 0); 454 if (!gpio_is_valid(par->reset)) { 455 ret = -EINVAL; 456 goto fb_alloc_error; 457 } 458 459 if (of_property_read_u32(node, "solomon,width", &par->width)) 460 par->width = 96; 461 462 if (of_property_read_u32(node, "solomon,height", &par->height)) 463 par->width = 16; 464 465 if (of_property_read_u32(node, "solomon,page-offset", &par->page_offset)) 466 par->page_offset = 1; 467 468 vmem_size = par->width * par->height / 8; 469 470 vmem = devm_kzalloc(&client->dev, vmem_size, GFP_KERNEL); 471 if (!vmem) { 472 dev_err(&client->dev, "Couldn't allocate graphical memory.\n"); 473 ret = -ENOMEM; 474 goto fb_alloc_error; 475 } 476 477 info->fbops = &ssd1307fb_ops; 478 info->fix = ssd1307fb_fix; 479 info->fix.line_length = par->width / 8; 480 info->fbdefio = &ssd1307fb_defio; 481 482 info->var = ssd1307fb_var; 483 info->var.xres = par->width; 484 info->var.xres_virtual = par->width; 485 info->var.yres = par->height; 486 info->var.yres_virtual = par->height; 487 488 info->var.red.length = 1; 489 info->var.red.offset = 0; 490 info->var.green.length = 1; 491 info->var.green.offset = 0; 492 info->var.blue.length = 1; 493 info->var.blue.offset = 0; 494 495 info->screen_base = (u8 __force __iomem *)vmem; 496 info->fix.smem_start = (unsigned long)vmem; 497 info->fix.smem_len = vmem_size; 498 499 fb_deferred_io_init(info); 500 501 ret = devm_gpio_request_one(&client->dev, par->reset, 502 GPIOF_OUT_INIT_HIGH, 503 "oled-reset"); 504 if (ret) { 505 dev_err(&client->dev, 506 "failed to request gpio %d: %d\n", 507 par->reset, ret); 508 goto reset_oled_error; 509 } 510 511 i2c_set_clientdata(client, info); 512 513 /* Reset the screen */ 514 gpio_set_value(par->reset, 0); 515 udelay(4); 516 gpio_set_value(par->reset, 1); 517 udelay(4); 518 519 if (par->ops->init) { 520 ret = par->ops->init(par); 521 if (ret) 522 goto reset_oled_error; 523 } 524 525 ret = register_framebuffer(info); 526 if (ret) { 527 dev_err(&client->dev, "Couldn't register the framebuffer\n"); 528 goto panel_init_error; 529 } 530 531 dev_info(&client->dev, "fb%d: %s framebuffer device registered, using %d bytes of video memory\n", info->node, info->fix.id, vmem_size); 532 533 return 0; 534 535 panel_init_error: 536 if (par->ops->remove) 537 par->ops->remove(par); 538 reset_oled_error: 539 fb_deferred_io_cleanup(info); 540 fb_alloc_error: 541 framebuffer_release(info); 542 return ret; 543 } 544 545 static int ssd1307fb_remove(struct i2c_client *client) 546 { 547 struct fb_info *info = i2c_get_clientdata(client); 548 struct ssd1307fb_par *par = info->par; 549 550 unregister_framebuffer(info); 551 if (par->ops->remove) 552 par->ops->remove(par); 553 fb_deferred_io_cleanup(info); 554 framebuffer_release(info); 555 556 return 0; 557 } 558 559 static const struct i2c_device_id ssd1307fb_i2c_id[] = { 560 { "ssd1306fb", 0 }, 561 { "ssd1307fb", 0 }, 562 { } 563 }; 564 MODULE_DEVICE_TABLE(i2c, ssd1307fb_i2c_id); 565 566 static struct i2c_driver ssd1307fb_driver = { 567 .probe = ssd1307fb_probe, 568 .remove = ssd1307fb_remove, 569 .id_table = ssd1307fb_i2c_id, 570 .driver = { 571 .name = "ssd1307fb", 572 .of_match_table = ssd1307fb_of_match, 573 .owner = THIS_MODULE, 574 }, 575 }; 576 577 module_i2c_driver(ssd1307fb_driver); 578 579 MODULE_DESCRIPTION("FB driver for the Solomon SSD1307 OLED controller"); 580 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>"); 581 MODULE_LICENSE("GPL"); 582