drivers/video/fbdev/ssd1307fb.c

   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/backlight.h>
  10 #include <linux/delay.h>
  11 #include <linux/fb.h>
  12 #include <linux/i2c.h>
  13 #include <linux/kernel.h>
  14 #include <linux/module.h>
  15 #include <linux/of_device.h>
  16 #include <linux/of_gpio.h>
  17 #include <linux/pwm.h>
  18 #include <linux/uaccess.h>
  19
  20 #define SSD1307FB_DATA                  0x40
  21 #define SSD1307FB_COMMAND               0x80
  22
  23 #define SSD1307FB_SET_ADDRESS_MODE      0x20
  24 #define SSD1307FB_SET_ADDRESS_MODE_HORIZONTAL   (0x00)
  25 #define SSD1307FB_SET_ADDRESS_MODE_VERTICAL     (0x01)
  26 #define SSD1307FB_SET_ADDRESS_MODE_PAGE         (0x02)
  27 #define SSD1307FB_SET_COL_RANGE         0x21
  28 #define SSD1307FB_SET_PAGE_RANGE        0x22
  29 #define SSD1307FB_CONTRAST              0x81
  30 #define SSD1307FB_CHARGE_PUMP           0x8d
  31 #define SSD1307FB_SEG_REMAP_ON          0xa1
  32 #define SSD1307FB_DISPLAY_OFF           0xae
  33 #define SSD1307FB_SET_MULTIPLEX_RATIO   0xa8
  34 #define SSD1307FB_DISPLAY_ON            0xaf
  35 #define SSD1307FB_START_PAGE_ADDRESS    0xb0
  36 #define SSD1307FB_SET_DISPLAY_OFFSET    0xd3
  37 #define SSD1307FB_SET_CLOCK_FREQ        0xd5
  38 #define SSD1307FB_SET_PRECHARGE_PERIOD  0xd9
  39 #define SSD1307FB_SET_COM_PINS_CONFIG   0xda
  40 #define SSD1307FB_SET_VCOMH             0xdb
  41
  42 #define MAX_CONTRAST 255
  43
  44 #define REFRESHRATE 1
  45
  46 static u_int refreshrate = REFRESHRATE;
  47 module_param(refreshrate, uint, 0);
  48
  49 struct ssd1307fb_par;
  50
  51 struct ssd1307fb_deviceinfo {
  52         u32 default_vcomh;
  53         u32 default_dclk_div;
  54         u32 default_dclk_frq;
  55         int need_pwm;
  56         int need_chargepump;
  57 };
  58
  59 struct ssd1307fb_par {
  60         u32 com_invdir;
  61         u32 com_lrremap;
  62         u32 com_offset;
  63         u32 com_seq;
  64         u32 contrast;
  65         u32 dclk_div;
  66         u32 dclk_frq;
  67         struct ssd1307fb_deviceinfo *device_info;
  68         struct i2c_client *client;
  69         u32 height;
  70         struct fb_info *info;
  71         u32 page_offset;
  72         u32 prechargep1;
  73         u32 prechargep2;
  74         struct pwm_device *pwm;
  75         u32 pwm_period;
  76         int reset;
  77         u32 seg_remap;
  78         u32 vcomh;
  79         u32 width;
  80 };
  81
  82 struct ssd1307fb_array {
  83         u8      type;
  84         u8      data[0];
  85 };
  86
  87 static struct fb_fix_screeninfo ssd1307fb_fix = {
  88         .id             = "Solomon SSD1307",
  89         .type           = FB_TYPE_PACKED_PIXELS,
  90         .visual         = FB_VISUAL_MONO10,
  91         .xpanstep       = 0,
  92         .ypanstep       = 0,
  93         .ywrapstep      = 0,
  94         .accel          = FB_ACCEL_NONE,
  95 };
  96
  97 static struct fb_var_screeninfo ssd1307fb_var = {
  98         .bits_per_pixel = 1,
  99 };
 100
 101 static struct ssd1307fb_array *ssd1307fb_alloc_array(u32 len, u8 type)
 102 {
 103         struct ssd1307fb_array *array;
 104
 105         array = kzalloc(sizeof(struct ssd1307fb_array) + len, GFP_KERNEL);
 106         if (!array)
 107                 return NULL;
 108
 109         array->type = type;
 110
 111         return array;
 112 }
 113
 114 static int ssd1307fb_write_array(struct i2c_client *client,
 115                                  struct ssd1307fb_array *array, u32 len)
 116 {
 117         int ret;
 118
 119         len += sizeof(struct ssd1307fb_array);
 120
 121         ret = i2c_master_send(client, (u8 *)array, len);
 122         if (ret != len) {
 123                 dev_err(&client->dev, "Couldn't send I2C command.\n");
 124                 return ret;
 125         }
 126
 127         return 0;
 128 }
 129
 130 static inline int ssd1307fb_write_cmd(struct i2c_client *client, u8 cmd)
 131 {
 132         struct ssd1307fb_array *array;
 133         int ret;
 134
 135         array = ssd1307fb_alloc_array(1, SSD1307FB_COMMAND);
 136         if (!array)
 137                 return -ENOMEM;
 138
 139         array->data[0] = cmd;
 140
 141         ret = ssd1307fb_write_array(client, array, 1);
 142         kfree(array);
 143
 144         return ret;
 145 }
 146
 147 static void ssd1307fb_update_display(struct ssd1307fb_par *par)
 148 {
 149         struct ssd1307fb_array *array;
 150         u8 *vmem = par->info->screen_base;
 151         int i, j, k;
 152
 153         array = ssd1307fb_alloc_array(par->width * par->height / 8,
 154                                       SSD1307FB_DATA);
 155         if (!array)
 156                 return;
 157
 158         /*
 159          * The screen is divided in pages, each having a height of 8
 160          * pixels, and the width of the screen. When sending a byte of
 161          * data to the controller, it gives the 8 bits for the current
 162          * column. I.e, the first byte are the 8 bits of the first
 163          * column, then the 8 bits for the second column, etc.
 164          *
 165          *
 166          * Representation of the screen, assuming it is 5 bits
 167          * wide. Each letter-number combination is a bit that controls
 168          * one pixel.
 169          *
 170          * A0 A1 A2 A3 A4
 171          * B0 B1 B2 B3 B4
 172          * C0 C1 C2 C3 C4
 173          * D0 D1 D2 D3 D4
 174          * E0 E1 E2 E3 E4
 175          * F0 F1 F2 F3 F4
 176          * G0 G1 G2 G3 G4
 177          * H0 H1 H2 H3 H4
 178          *
 179          * If you want to update this screen, you need to send 5 bytes:
 180          *  (1) A0 B0 C0 D0 E0 F0 G0 H0
 181          *  (2) A1 B1 C1 D1 E1 F1 G1 H1
 182          *  (3) A2 B2 C2 D2 E2 F2 G2 H2
 183          *  (4) A3 B3 C3 D3 E3 F3 G3 H3
 184          *  (5) A4 B4 C4 D4 E4 F4 G4 H4
 185          */
 186
 187         for (i = 0; i < (par->height / 8); i++) {
 188                 for (j = 0; j < par->width; j++) {
 189                         u32 array_idx = i * par->width + j;
 190                         array->data[array_idx] = 0;
 191                         for (k = 0; k < 8; k++) {
 192                                 u32 page_length = par->width * i;
 193                                 u32 index = page_length + (par->width * k + j) / 8;
 194                                 u8 byte = *(vmem + index);
 195                                 u8 bit = byte & (1 << (j % 8));
 196                                 bit = bit >> (j % 8);
 197                                 array->data[array_idx] |= bit << k;
 198                         }
 199                 }
 200         }
 201
 202         ssd1307fb_write_array(par->client, array, par->width * par->height / 8);
 203         kfree(array);
 204 }
 205
 206
 207 static ssize_t ssd1307fb_write(struct fb_info *info, const char __user *buf,
 208                 size_t count, loff_t *ppos)
 209 {
 210         struct ssd1307fb_par *par = info->par;
 211         unsigned long total_size;
 212         unsigned long p = *ppos;
 213         u8 __iomem *dst;
 214
 215         total_size = info->fix.smem_len;
 216
 217         if (p > total_size)
 218                 return -EINVAL;
 219
 220         if (count + p > total_size)
 221                 count = total_size - p;
 222
 223         if (!count)
 224                 return -EINVAL;
 225
 226         dst = (void __force *) (info->screen_base + p);
 227
 228         if (copy_from_user(dst, buf, count))
 229                 return -EFAULT;
 230
 231         ssd1307fb_update_display(par);
 232
 233         *ppos += count;
 234
 235         return count;
 236 }
 237
 238 static int ssd1307fb_blank(int blank_mode, struct fb_info *info)
 239 {
 240         struct ssd1307fb_par *par = info->par;
 241
 242         if (blank_mode != FB_BLANK_UNBLANK)
 243                 return ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_OFF);
 244         else
 245                 return ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_ON);
 246 }
 247
 248 static void ssd1307fb_fillrect(struct fb_info *info, const struct fb_fillrect *rect)
 249 {
 250         struct ssd1307fb_par *par = info->par;
 251         sys_fillrect(info, rect);
 252         ssd1307fb_update_display(par);
 253 }
 254
 255 static void ssd1307fb_copyarea(struct fb_info *info, const struct fb_copyarea *area)
 256 {
 257         struct ssd1307fb_par *par = info->par;
 258         sys_copyarea(info, area);
 259         ssd1307fb_update_display(par);
 260 }
 261
 262 static void ssd1307fb_imageblit(struct fb_info *info, const struct fb_image *image)
 263 {
 264         struct ssd1307fb_par *par = info->par;
 265         sys_imageblit(info, image);
 266         ssd1307fb_update_display(par);
 267 }
 268
 269 static struct fb_ops ssd1307fb_ops = {
 270         .owner          = THIS_MODULE,
 271         .fb_read        = fb_sys_read,
 272         .fb_write       = ssd1307fb_write,
 273         .fb_blank       = ssd1307fb_blank,
 274         .fb_fillrect    = ssd1307fb_fillrect,
 275         .fb_copyarea    = ssd1307fb_copyarea,
 276         .fb_imageblit   = ssd1307fb_imageblit,
 277 };
 278
 279 static void ssd1307fb_deferred_io(struct fb_info *info,
 280                                 struct list_head *pagelist)
 281 {
 282         ssd1307fb_update_display(info->par);
 283 }
 284
 285 static int ssd1307fb_init(struct ssd1307fb_par *par)
 286 {
 287         int ret;
 288         u32 precharge, dclk, com_invdir, compins;
 289
 290         if (par->device_info->need_pwm) {
 291                 par->pwm = pwm_get(&par->client->dev, NULL);
 292                 if (IS_ERR(par->pwm)) {
 293                         dev_err(&par->client->dev, "Could not get PWM from device tree!\n");
 294                         return PTR_ERR(par->pwm);
 295                 }
 296
 297                 par->pwm_period = pwm_get_period(par->pwm);
 298                 /* Enable the PWM */
 299                 pwm_config(par->pwm, par->pwm_period / 2, par->pwm_period);
 300                 pwm_enable(par->pwm);
 301
 302                 dev_dbg(&par->client->dev, "Using PWM%d with a %dns period.\n",
 303                         par->pwm->pwm, par->pwm_period);
 304         };
 305
 306         /* Set initial contrast */
 307         ret = ssd1307fb_write_cmd(par->client, SSD1307FB_CONTRAST);
 308         if (ret < 0)
 309                 return ret;
 310
 311         ret = ssd1307fb_write_cmd(par->client, par->contrast);
 312         if (ret < 0)
 313                 return ret;
 314
 315         /* Set segment re-map */
 316         if (par->seg_remap) {
 317                 ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SEG_REMAP_ON);
 318                 if (ret < 0)
 319                         return ret;
 320         };
 321
 322         /* Set COM direction */
 323         com_invdir = 0xc0 | (par->com_invdir & 0x1) << 3;
 324         ret = ssd1307fb_write_cmd(par->client,  com_invdir);
 325         if (ret < 0)
 326                 return ret;
 327
 328         /* Set multiplex ratio value */
 329         ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_MULTIPLEX_RATIO);
 330         if (ret < 0)
 331                 return ret;
 332
 333         ret = ssd1307fb_write_cmd(par->client, par->height - 1);
 334         if (ret < 0)
 335                 return ret;
 336
 337         /* set display offset value */
 338         ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_DISPLAY_OFFSET);
 339         if (ret < 0)
 340                 return ret;
 341
 342         ret = ssd1307fb_write_cmd(par->client, par->com_offset);
 343         if (ret < 0)
 344                 return ret;
 345
 346         /* Set clock frequency */
 347         ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_CLOCK_FREQ);
 348         if (ret < 0)
 349                 return ret;
 350
 351         dclk = ((par->dclk_div - 1) & 0xf) | (par->dclk_frq & 0xf) << 4;
 352         ret = ssd1307fb_write_cmd(par->client, dclk);
 353         if (ret < 0)
 354                 return ret;
 355
 356         /* Set precharge period in number of ticks from the internal clock */
 357         ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_PRECHARGE_PERIOD);
 358         if (ret < 0)
 359                 return ret;
 360
 361         precharge = (par->prechargep1 & 0xf) | (par->prechargep2 & 0xf) << 4;
 362         ret = ssd1307fb_write_cmd(par->client, precharge);
 363         if (ret < 0)
 364                 return ret;
 365
 366         /* Set COM pins configuration */
 367         ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_COM_PINS_CONFIG);
 368         if (ret < 0)
 369                 return ret;
 370
 371         compins = 0x02 | !(par->com_seq & 0x1) << 4
 372                                    | (par->com_lrremap & 0x1) << 5;
 373         ret = ssd1307fb_write_cmd(par->client, compins);
 374         if (ret < 0)
 375                 return ret;
 376
 377         /* Set VCOMH */
 378         ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_VCOMH);
 379         if (ret < 0)
 380                 return ret;
 381
 382         ret = ssd1307fb_write_cmd(par->client, par->vcomh);
 383         if (ret < 0)
 384                 return ret;
 385
 386         /* Turn on the DC-DC Charge Pump */
 387         ret = ssd1307fb_write_cmd(par->client, SSD1307FB_CHARGE_PUMP);
 388         if (ret < 0)
 389                 return ret;
 390
 391         ret = ssd1307fb_write_cmd(par->client,
 392                 (par->device_info->need_chargepump & 0x1 << 2) & 0x14);
 393         if (ret < 0)
 394                 return ret;
 395
 396         /* Switch to horizontal addressing mode */
 397         ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_ADDRESS_MODE);
 398         if (ret < 0)
 399                 return ret;
 400
 401         ret = ssd1307fb_write_cmd(par->client,
 402                                   SSD1307FB_SET_ADDRESS_MODE_HORIZONTAL);
 403         if (ret < 0)
 404                 return ret;
 405
 406         /* Set column range */
 407         ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_COL_RANGE);
 408         if (ret < 0)
 409                 return ret;
 410
 411         ret = ssd1307fb_write_cmd(par->client, 0x0);
 412         if (ret < 0)
 413                 return ret;
 414
 415         ret = ssd1307fb_write_cmd(par->client, par->width - 1);
 416         if (ret < 0)
 417                 return ret;
 418
 419         /* Set page range */
 420         ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_PAGE_RANGE);
 421         if (ret < 0)
 422                 return ret;
 423
 424         ret = ssd1307fb_write_cmd(par->client, 0x0);
 425         if (ret < 0)
 426                 return ret;
 427
 428         ret = ssd1307fb_write_cmd(par->client,
 429                                   par->page_offset + (par->height / 8) - 1);
 430         if (ret < 0)
 431                 return ret;
 432
 433         /* Turn on the display */
 434         ret = ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_ON);
 435         if (ret < 0)
 436                 return ret;
 437
 438         return 0;
 439 }
 440
 441 static int ssd1307fb_update_bl(struct backlight_device *bdev)
 442 {
 443         struct ssd1307fb_par *par = bl_get_data(bdev);
 444         int ret;
 445         int brightness = bdev->props.brightness;
 446
 447         par->contrast = brightness;
 448
 449         ret = ssd1307fb_write_cmd(par->client, SSD1307FB_CONTRAST);
 450         if (ret < 0)
 451                 return ret;
 452         ret = ssd1307fb_write_cmd(par->client, par->contrast);
 453         if (ret < 0)
 454                 return ret;
 455         return 0;
 456 }
 457
 458 static int ssd1307fb_get_brightness(struct backlight_device *bdev)
 459 {
 460         struct ssd1307fb_par *par = bl_get_data(bdev);
 461
 462         return par->contrast;
 463 }
 464
 465 static int ssd1307fb_check_fb(struct backlight_device *bdev,
 466                                    struct fb_info *info)
 467 {
 468         return (info->bl_dev == bdev);
 469 }
 470
 471 static const struct backlight_ops ssd1307fb_bl_ops = {
 472         .options        = BL_CORE_SUSPENDRESUME,
 473         .update_status  = ssd1307fb_update_bl,
 474         .get_brightness = ssd1307fb_get_brightness,
 475         .check_fb       = ssd1307fb_check_fb,
 476 };
 477
 478 static struct ssd1307fb_deviceinfo ssd1307fb_ssd1305_deviceinfo = {
 479         .default_vcomh = 0x34,
 480         .default_dclk_div = 1,
 481         .default_dclk_frq = 7,
 482 };
 483
 484 static struct ssd1307fb_deviceinfo ssd1307fb_ssd1306_deviceinfo = {
 485         .default_vcomh = 0x20,
 486         .default_dclk_div = 1,
 487         .default_dclk_frq = 8,
 488         .need_chargepump = 1,
 489 };
 490
 491 static struct ssd1307fb_deviceinfo ssd1307fb_ssd1307_deviceinfo = {
 492         .default_vcomh = 0x20,
 493         .default_dclk_div = 2,
 494         .default_dclk_frq = 12,
 495         .need_pwm = 1,
 496 };
 497
 498 static struct ssd1307fb_deviceinfo ssd1307fb_ssd1309_deviceinfo = {
 499         .default_vcomh = 0x34,
 500         .default_dclk_div = 1,
 501         .default_dclk_frq = 10,
 502 };
 503
 504 static const struct of_device_id ssd1307fb_of_match[] = {
 505         {
 506                 .compatible = "solomon,ssd1305fb-i2c",
 507                 .data = (void *)&ssd1307fb_ssd1305_deviceinfo,
 508         },
 509         {
 510                 .compatible = "solomon,ssd1306fb-i2c",
 511                 .data = (void *)&ssd1307fb_ssd1306_deviceinfo,
 512         },
 513         {
 514                 .compatible = "solomon,ssd1307fb-i2c",
 515                 .data = (void *)&ssd1307fb_ssd1307_deviceinfo,
 516         },
 517         {
 518                 .compatible = "solomon,ssd1309fb-i2c",
 519                 .data = (void *)&ssd1307fb_ssd1309_deviceinfo,
 520         },
 521         {},
 522 };
 523 MODULE_DEVICE_TABLE(of, ssd1307fb_of_match);
 524
 525 static int ssd1307fb_probe(struct i2c_client *client,
 526                            const struct i2c_device_id *id)
 527 {
 528         struct backlight_device *bl;
 529         char bl_name[12];
 530         struct fb_info *info;
 531         struct device_node *node = client->dev.of_node;
 532         struct fb_deferred_io *ssd1307fb_defio;
 533         u32 vmem_size;
 534         struct ssd1307fb_par *par;
 535         u8 *vmem;
 536         int ret;
 537
 538         if (!node) {
 539                 dev_err(&client->dev, "No device tree data found!\n");
 540                 return -EINVAL;
 541         }
 542
 543         info = framebuffer_alloc(sizeof(struct ssd1307fb_par), &client->dev);
 544         if (!info) {
 545                 dev_err(&client->dev, "Couldn't allocate framebuffer.\n");
 546                 return -ENOMEM;
 547         }
 548
 549         par = info->par;
 550         par->info = info;
 551         par->client = client;
 552
 553         par->device_info = (struct ssd1307fb_deviceinfo *)of_match_device(
 554                         ssd1307fb_of_match, &client->dev)->data;
 555
 556         par->reset = of_get_named_gpio(client->dev.of_node,
 557                                          "reset-gpios", 0);
 558         if (!gpio_is_valid(par->reset)) {
 559                 ret = -EINVAL;
 560                 goto fb_alloc_error;
 561         }
 562
 563         if (of_property_read_u32(node, "solomon,width", &par->width))
 564                 par->width = 96;
 565
 566         if (of_property_read_u32(node, "solomon,height", &par->height))
 567                 par->height = 16;
 568
 569         if (of_property_read_u32(node, "solomon,page-offset", &par->page_offset))
 570                 par->page_offset = 1;
 571
 572         if (of_property_read_u32(node, "solomon,com-offset", &par->com_offset))
 573                 par->com_offset = 0;
 574
 575         if (of_property_read_u32(node, "solomon,prechargep1", &par->prechargep1))
 576                 par->prechargep1 = 2;
 577
 578         if (of_property_read_u32(node, "solomon,prechargep2", &par->prechargep2))
 579                 par->prechargep2 = 2;
 580
 581         par->seg_remap = !of_property_read_bool(node, "solomon,segment-no-remap");
 582         par->com_seq = of_property_read_bool(node, "solomon,com-seq");
 583         par->com_lrremap = of_property_read_bool(node, "solomon,com-lrremap");
 584         par->com_invdir = of_property_read_bool(node, "solomon,com-invdir");
 585
 586         par->contrast = 127;
 587         par->vcomh = par->device_info->default_vcomh;
 588
 589         /* Setup display timing */
 590         par->dclk_div = par->device_info->default_dclk_div;
 591         par->dclk_frq = par->device_info->default_dclk_frq;
 592
 593         vmem_size = par->width * par->height / 8;
 594
 595         vmem = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
 596                                         get_order(vmem_size));
 597         if (!vmem) {
 598                 dev_err(&client->dev, "Couldn't allocate graphical memory.\n");
 599                 ret = -ENOMEM;
 600                 goto fb_alloc_error;
 601         }
 602
 603         ssd1307fb_defio = devm_kzalloc(&client->dev, sizeof(struct fb_deferred_io), GFP_KERNEL);
 604         if (!ssd1307fb_defio) {
 605                 dev_err(&client->dev, "Couldn't allocate deferred io.\n");
 606                 ret = -ENOMEM;
 607                 goto fb_alloc_error;
 608         }
 609
 610         ssd1307fb_defio->delay = HZ / refreshrate;
 611         ssd1307fb_defio->deferred_io = ssd1307fb_deferred_io;
 612
 613         info->fbops = &ssd1307fb_ops;
 614         info->fix = ssd1307fb_fix;
 615         info->fix.line_length = par->width / 8;
 616         info->fbdefio = ssd1307fb_defio;
 617
 618         info->var = ssd1307fb_var;
 619         info->var.xres = par->width;
 620         info->var.xres_virtual = par->width;
 621         info->var.yres = par->height;
 622         info->var.yres_virtual = par->height;
 623
 624         info->var.red.length = 1;
 625         info->var.red.offset = 0;
 626         info->var.green.length = 1;
 627         info->var.green.offset = 0;
 628         info->var.blue.length = 1;
 629         info->var.blue.offset = 0;
 630
 631         info->screen_base = (u8 __force __iomem *)vmem;
 632         info->fix.smem_start = __pa(vmem);
 633         info->fix.smem_len = vmem_size;
 634
 635         fb_deferred_io_init(info);
 636
 637         ret = devm_gpio_request_one(&client->dev, par->reset,
 638                                     GPIOF_OUT_INIT_HIGH,
 639                                     "oled-reset");
 640         if (ret) {
 641                 dev_err(&client->dev,
 642                         "failed to request gpio %d: %d\n",
 643                         par->reset, ret);
 644                 goto reset_oled_error;
 645         }
 646
 647         i2c_set_clientdata(client, info);
 648
 649         /* Reset the screen */
 650         gpio_set_value(par->reset, 0);
 651         udelay(4);
 652         gpio_set_value(par->reset, 1);
 653         udelay(4);
 654
 655         ret = ssd1307fb_init(par);
 656         if (ret)
 657                 goto reset_oled_error;
 658
 659         ret = register_framebuffer(info);
 660         if (ret) {
 661                 dev_err(&client->dev, "Couldn't register the framebuffer\n");
 662                 goto panel_init_error;
 663         }
 664
 665         snprintf(bl_name, sizeof(bl_name), "ssd1307fb%d", info->node);
 666         bl = backlight_device_register(bl_name, &client->dev, par,
 667                                        &ssd1307fb_bl_ops, NULL);
 668         if (IS_ERR(bl)) {
 669                 ret = PTR_ERR(bl);
 670                 dev_err(&client->dev, "unable to register backlight device: %d\n",
 671                         ret);
 672                 goto bl_init_error;
 673         }
 674
 675         bl->props.brightness = par->contrast;
 676         bl->props.max_brightness = MAX_CONTRAST;
 677         info->bl_dev = bl;
 678
 679         dev_info(&client->dev, "fb%d: %s framebuffer device registered, using %d bytes of video memory\n", info->node, info->fix.id, vmem_size);
 680
 681         return 0;
 682
 683 bl_init_error:
 684         unregister_framebuffer(info);
 685 panel_init_error:
 686         if (par->device_info->need_pwm) {
 687                 pwm_disable(par->pwm);
 688                 pwm_put(par->pwm);
 689         };
 690 reset_oled_error:
 691         fb_deferred_io_cleanup(info);
 692 fb_alloc_error:
 693         framebuffer_release(info);
 694         return ret;
 695 }
 696
 697 static int ssd1307fb_remove(struct i2c_client *client)
 698 {
 699         struct fb_info *info = i2c_get_clientdata(client);
 700         struct ssd1307fb_par *par = info->par;
 701
 702         ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_OFF);
 703
 704         backlight_device_unregister(info->bl_dev);
 705
 706         unregister_framebuffer(info);
 707         if (par->device_info->need_pwm) {
 708                 pwm_disable(par->pwm);
 709                 pwm_put(par->pwm);
 710         };
 711         fb_deferred_io_cleanup(info);
 712         __free_pages(__va(info->fix.smem_start), get_order(info->fix.smem_len));
 713         framebuffer_release(info);
 714
 715         return 0;
 716 }
 717
 718 static const struct i2c_device_id ssd1307fb_i2c_id[] = {
 719         { "ssd1305fb", 0 },
 720         { "ssd1306fb", 0 },
 721         { "ssd1307fb", 0 },
 722         { "ssd1309fb", 0 },
 723         { }
 724 };
 725 MODULE_DEVICE_TABLE(i2c, ssd1307fb_i2c_id);
 726
 727 static struct i2c_driver ssd1307fb_driver = {
 728         .probe = ssd1307fb_probe,
 729         .remove = ssd1307fb_remove,
 730         .id_table = ssd1307fb_i2c_id,
 731         .driver = {
 732                 .name = "ssd1307fb",
 733                 .of_match_table = ssd1307fb_of_match,
 734         },
 735 };
 736
 737 module_i2c_driver(ssd1307fb_driver);
 738
 739 MODULE_DESCRIPTION("FB driver for the Solomon SSD1307 OLED controller");
 740 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
 741 MODULE_LICENSE("GPL");