drivers/gpu/drm/tiny/repaper.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * DRM driver for Pervasive Displays RePaper branded e-ink panels
   4  *
   5  * Copyright 2013-2017 Pervasive Displays, Inc.
   6  * Copyright 2017 Noralf Trønnes
   7  *
   8  * The driver supports:
   9  * Material Film: Aurora Mb (V231)
  10  * Driver IC: G2 (eTC)
  11  *
  12  * The controller code was taken from the userspace driver:
  13  * https://github.com/repaper/gratis
  14  */
  15
  16 #include <linux/delay.h>
  17 #include <linux/gpio/consumer.h>
  18 #include <linux/module.h>
  19 #include <linux/property.h>
  20 #include <linux/sched/clock.h>
  21 #include <linux/spi/spi.h>
  22 #include <linux/thermal.h>
  23
  24 #include <drm/drm_atomic_helper.h>
  25 #include <drm/drm_connector.h>
  26 #include <drm/drm_damage_helper.h>
  27 #include <drm/drm_drv.h>
  28 #include <drm/drm_fb_dma_helper.h>
  29 #include <drm/drm_fbdev_generic.h>
  30 #include <drm/drm_format_helper.h>
  31 #include <drm/drm_framebuffer.h>
  32 #include <drm/drm_gem_atomic_helper.h>
  33 #include <drm/drm_gem_dma_helper.h>
  34 #include <drm/drm_gem_framebuffer_helper.h>
  35 #include <drm/drm_managed.h>
  36 #include <drm/drm_modes.h>
  37 #include <drm/drm_rect.h>
  38 #include <drm/drm_probe_helper.h>
  39 #include <drm/drm_simple_kms_helper.h>
  40
  41 #define REPAPER_RID_G2_COG_ID   0x12
  42
  43 enum repaper_model {
  44         /* 0 is reserved to avoid clashing with NULL */
  45         E1144CS021 = 1,
  46         E1190CS021,
  47         E2200CS021,
  48         E2271CS021,
  49 };
  50
  51 enum repaper_stage {         /* Image pixel -> Display pixel */
  52         REPAPER_COMPENSATE,  /* B -> W, W -> B (Current Image) */
  53         REPAPER_WHITE,       /* B -> N, W -> W (Current Image) */
  54         REPAPER_INVERSE,     /* B -> N, W -> B (New Image) */
  55         REPAPER_NORMAL       /* B -> B, W -> W (New Image) */
  56 };
  57
  58 enum repaper_epd_border_byte {
  59         REPAPER_BORDER_BYTE_NONE,
  60         REPAPER_BORDER_BYTE_ZERO,
  61         REPAPER_BORDER_BYTE_SET,
  62 };
  63
  64 struct repaper_epd {
  65         struct drm_device drm;
  66         struct drm_simple_display_pipe pipe;
  67         const struct drm_display_mode *mode;
  68         struct drm_connector connector;
  69         struct spi_device *spi;
  70
  71         struct gpio_desc *panel_on;
  72         struct gpio_desc *border;
  73         struct gpio_desc *discharge;
  74         struct gpio_desc *reset;
  75         struct gpio_desc *busy;
  76
  77         struct thermal_zone_device *thermal;
  78
  79         unsigned int height;
  80         unsigned int width;
  81         unsigned int bytes_per_scan;
  82         const u8 *channel_select;
  83         unsigned int stage_time;
  84         unsigned int factored_stage_time;
  85         bool middle_scan;
  86         bool pre_border_byte;
  87         enum repaper_epd_border_byte border_byte;
  88
  89         u8 *line_buffer;
  90         void *current_frame;
  91
  92         bool cleared;
  93         bool partial;
  94 };
  95
  96 static inline struct repaper_epd *drm_to_epd(struct drm_device *drm)
  97 {
  98         return container_of(drm, struct repaper_epd, drm);
  99 }
 100
 101 static int repaper_spi_transfer(struct spi_device *spi, u8 header,
 102                                 const void *tx, void *rx, size_t len)
 103 {
 104         void *txbuf = NULL, *rxbuf = NULL;
 105         struct spi_transfer tr[2] = {};
 106         u8 *headerbuf;
 107         int ret;
 108
 109         headerbuf = kmalloc(1, GFP_KERNEL);
 110         if (!headerbuf)
 111                 return -ENOMEM;
 112
 113         headerbuf[0] = header;
 114         tr[0].tx_buf = headerbuf;
 115         tr[0].len = 1;
 116
 117         /* Stack allocated tx? */
 118         if (tx && len <= 32) {
 119                 txbuf = kmemdup(tx, len, GFP_KERNEL);
 120                 if (!txbuf) {
 121                         ret = -ENOMEM;
 122                         goto out_free;
 123                 }
 124         }
 125
 126         if (rx) {
 127                 rxbuf = kmalloc(len, GFP_KERNEL);
 128                 if (!rxbuf) {
 129                         ret = -ENOMEM;
 130                         goto out_free;
 131                 }
 132         }
 133
 134         tr[1].tx_buf = txbuf ? txbuf : tx;
 135         tr[1].rx_buf = rxbuf;
 136         tr[1].len = len;
 137
 138         ndelay(80);
 139         ret = spi_sync_transfer(spi, tr, 2);
 140         if (rx && !ret)
 141                 memcpy(rx, rxbuf, len);
 142
 143 out_free:
 144         kfree(headerbuf);
 145         kfree(txbuf);
 146         kfree(rxbuf);
 147
 148         return ret;
 149 }
 150
 151 static int repaper_write_buf(struct spi_device *spi, u8 reg,
 152                              const u8 *buf, size_t len)
 153 {
 154         int ret;
 155
 156         ret = repaper_spi_transfer(spi, 0x70, &reg, NULL, 1);
 157         if (ret)
 158                 return ret;
 159
 160         return repaper_spi_transfer(spi, 0x72, buf, NULL, len);
 161 }
 162
 163 static int repaper_write_val(struct spi_device *spi, u8 reg, u8 val)
 164 {
 165         return repaper_write_buf(spi, reg, &val, 1);
 166 }
 167
 168 static int repaper_read_val(struct spi_device *spi, u8 reg)
 169 {
 170         int ret;
 171         u8 val;
 172
 173         ret = repaper_spi_transfer(spi, 0x70, &reg, NULL, 1);
 174         if (ret)
 175                 return ret;
 176
 177         ret = repaper_spi_transfer(spi, 0x73, NULL, &val, 1);
 178
 179         return ret ? ret : val;
 180 }
 181
 182 static int repaper_read_id(struct spi_device *spi)
 183 {
 184         int ret;
 185         u8 id;
 186
 187         ret = repaper_spi_transfer(spi, 0x71, NULL, &id, 1);
 188
 189         return ret ? ret : id;
 190 }
 191
 192 static void repaper_spi_mosi_low(struct spi_device *spi)
 193 {
 194         const u8 buf[1] = { 0 };
 195
 196         spi_write(spi, buf, 1);
 197 }
 198
 199 /* pixels on display are numbered from 1 so even is actually bits 1,3,5,... */
 200 static void repaper_even_pixels(struct repaper_epd *epd, u8 **pp,
 201                                 const u8 *data, u8 fixed_value, const u8 *mask,
 202                                 enum repaper_stage stage)
 203 {
 204         unsigned int b;
 205
 206         for (b = 0; b < (epd->width / 8); b++) {
 207                 if (data) {
 208                         u8 pixels = data[b] & 0xaa;
 209                         u8 pixel_mask = 0xff;
 210                         u8 p1, p2, p3, p4;
 211
 212                         if (mask) {
 213                                 pixel_mask = (mask[b] ^ pixels) & 0xaa;
 214                                 pixel_mask |= pixel_mask >> 1;
 215                         }
 216
 217                         switch (stage) {
 218                         case REPAPER_COMPENSATE: /* B -> W, W -> B (Current) */
 219                                 pixels = 0xaa | ((pixels ^ 0xaa) >> 1);
 220                                 break;
 221                         case REPAPER_WHITE:      /* B -> N, W -> W (Current) */
 222                                 pixels = 0x55 + ((pixels ^ 0xaa) >> 1);
 223                                 break;
 224                         case REPAPER_INVERSE:    /* B -> N, W -> B (New) */
 225                                 pixels = 0x55 | (pixels ^ 0xaa);
 226                                 break;
 227                         case REPAPER_NORMAL:     /* B -> B, W -> W (New) */
 228                                 pixels = 0xaa | (pixels >> 1);
 229                                 break;
 230                         }
 231
 232                         pixels = (pixels & pixel_mask) | (~pixel_mask & 0x55);
 233                         p1 = (pixels >> 6) & 0x03;
 234                         p2 = (pixels >> 4) & 0x03;
 235                         p3 = (pixels >> 2) & 0x03;
 236                         p4 = (pixels >> 0) & 0x03;
 237                         pixels = (p1 << 0) | (p2 << 2) | (p3 << 4) | (p4 << 6);
 238                         *(*pp)++ = pixels;
 239                 } else {
 240                         *(*pp)++ = fixed_value;
 241                 }
 242         }
 243 }
 244
 245 /* pixels on display are numbered from 1 so odd is actually bits 0,2,4,... */
 246 static void repaper_odd_pixels(struct repaper_epd *epd, u8 **pp,
 247                                const u8 *data, u8 fixed_value, const u8 *mask,
 248                                enum repaper_stage stage)
 249 {
 250         unsigned int b;
 251
 252         for (b = epd->width / 8; b > 0; b--) {
 253                 if (data) {
 254                         u8 pixels = data[b - 1] & 0x55;
 255                         u8 pixel_mask = 0xff;
 256
 257                         if (mask) {
 258                                 pixel_mask = (mask[b - 1] ^ pixels) & 0x55;
 259                                 pixel_mask |= pixel_mask << 1;
 260                         }
 261
 262                         switch (stage) {
 263                         case REPAPER_COMPENSATE: /* B -> W, W -> B (Current) */
 264                                 pixels = 0xaa | (pixels ^ 0x55);
 265                                 break;
 266                         case REPAPER_WHITE:      /* B -> N, W -> W (Current) */
 267                                 pixels = 0x55 + (pixels ^ 0x55);
 268                                 break;
 269                         case REPAPER_INVERSE:    /* B -> N, W -> B (New) */
 270                                 pixels = 0x55 | ((pixels ^ 0x55) << 1);
 271                                 break;
 272                         case REPAPER_NORMAL:     /* B -> B, W -> W (New) */
 273                                 pixels = 0xaa | pixels;
 274                                 break;
 275                         }
 276
 277                         pixels = (pixels & pixel_mask) | (~pixel_mask & 0x55);
 278                         *(*pp)++ = pixels;
 279                 } else {
 280                         *(*pp)++ = fixed_value;
 281                 }
 282         }
 283 }
 284
 285 /* interleave bits: (byte)76543210 -> (16 bit).7.6.5.4.3.2.1 */
 286 static inline u16 repaper_interleave_bits(u16 value)
 287 {
 288         value = (value | (value << 4)) & 0x0f0f;
 289         value = (value | (value << 2)) & 0x3333;
 290         value = (value | (value << 1)) & 0x5555;
 291
 292         return value;
 293 }
 294
 295 /* pixels on display are numbered from 1 */
 296 static void repaper_all_pixels(struct repaper_epd *epd, u8 **pp,
 297                                const u8 *data, u8 fixed_value, const u8 *mask,
 298                                enum repaper_stage stage)
 299 {
 300         unsigned int b;
 301
 302         for (b = epd->width / 8; b > 0; b--) {
 303                 if (data) {
 304                         u16 pixels = repaper_interleave_bits(data[b - 1]);
 305                         u16 pixel_mask = 0xffff;
 306
 307                         if (mask) {
 308                                 pixel_mask = repaper_interleave_bits(mask[b - 1]);
 309
 310                                 pixel_mask = (pixel_mask ^ pixels) & 0x5555;
 311                                 pixel_mask |= pixel_mask << 1;
 312                         }
 313
 314                         switch (stage) {
 315                         case REPAPER_COMPENSATE: /* B -> W, W -> B (Current) */
 316                                 pixels = 0xaaaa | (pixels ^ 0x5555);
 317                                 break;
 318                         case REPAPER_WHITE:      /* B -> N, W -> W (Current) */
 319                                 pixels = 0x5555 + (pixels ^ 0x5555);
 320                                 break;
 321                         case REPAPER_INVERSE:    /* B -> N, W -> B (New) */
 322                                 pixels = 0x5555 | ((pixels ^ 0x5555) << 1);
 323                                 break;
 324                         case REPAPER_NORMAL:     /* B -> B, W -> W (New) */
 325                                 pixels = 0xaaaa | pixels;
 326                                 break;
 327                         }
 328
 329                         pixels = (pixels & pixel_mask) | (~pixel_mask & 0x5555);
 330                         *(*pp)++ = pixels >> 8;
 331                         *(*pp)++ = pixels;
 332                 } else {
 333                         *(*pp)++ = fixed_value;
 334                         *(*pp)++ = fixed_value;
 335                 }
 336         }
 337 }
 338
 339 /* output one line of scan and data bytes to the display */
 340 static void repaper_one_line(struct repaper_epd *epd, unsigned int line,
 341                              const u8 *data, u8 fixed_value, const u8 *mask,
 342                              enum repaper_stage stage)
 343 {
 344         u8 *p = epd->line_buffer;
 345         unsigned int b;
 346
 347         repaper_spi_mosi_low(epd->spi);
 348
 349         if (epd->pre_border_byte)
 350                 *p++ = 0x00;
 351
 352         if (epd->middle_scan) {
 353                 /* data bytes */
 354                 repaper_odd_pixels(epd, &p, data, fixed_value, mask, stage);
 355
 356                 /* scan line */
 357                 for (b = epd->bytes_per_scan; b > 0; b--) {
 358                         if (line / 4 == b - 1)
 359                                 *p++ = 0x03 << (2 * (line & 0x03));
 360                         else
 361                                 *p++ = 0x00;
 362                 }
 363
 364                 /* data bytes */
 365                 repaper_even_pixels(epd, &p, data, fixed_value, mask, stage);
 366         } else {
 367                 /*
 368                  * even scan line, but as lines on display are numbered from 1,
 369                  * line: 1,3,5,...
 370                  */
 371                 for (b = 0; b < epd->bytes_per_scan; b++) {
 372                         if (0 != (line & 0x01) && line / 8 == b)
 373                                 *p++ = 0xc0 >> (line & 0x06);
 374                         else
 375                                 *p++ = 0x00;
 376                 }
 377
 378                 /* data bytes */
 379                 repaper_all_pixels(epd, &p, data, fixed_value, mask, stage);
 380
 381                 /*
 382                  * odd scan line, but as lines on display are numbered from 1,
 383                  * line: 0,2,4,6,...
 384                  */
 385                 for (b = epd->bytes_per_scan; b > 0; b--) {
 386                         if (0 == (line & 0x01) && line / 8 == b - 1)
 387                                 *p++ = 0x03 << (line & 0x06);
 388                         else
 389                                 *p++ = 0x00;
 390                 }
 391         }
 392
 393         switch (epd->border_byte) {
 394         case REPAPER_BORDER_BYTE_NONE:
 395                 break;
 396
 397         case REPAPER_BORDER_BYTE_ZERO:
 398                 *p++ = 0x00;
 399                 break;
 400
 401         case REPAPER_BORDER_BYTE_SET:
 402                 switch (stage) {
 403                 case REPAPER_COMPENSATE:
 404                 case REPAPER_WHITE:
 405                 case REPAPER_INVERSE:
 406                         *p++ = 0x00;
 407                         break;
 408                 case REPAPER_NORMAL:
 409                         *p++ = 0xaa;
 410                         break;
 411                 }
 412                 break;
 413         }
 414
 415         repaper_write_buf(epd->spi, 0x0a, epd->line_buffer,
 416                           p - epd->line_buffer);
 417
 418         /* Output data to panel */
 419         repaper_write_val(epd->spi, 0x02, 0x07);
 420
 421         repaper_spi_mosi_low(epd->spi);
 422 }
 423
 424 static void repaper_frame_fixed(struct repaper_epd *epd, u8 fixed_value,
 425                                 enum repaper_stage stage)
 426 {
 427         unsigned int line;
 428
 429         for (line = 0; line < epd->height; line++)
 430                 repaper_one_line(epd, line, NULL, fixed_value, NULL, stage);
 431 }
 432
 433 static void repaper_frame_data(struct repaper_epd *epd, const u8 *image,
 434                                const u8 *mask, enum repaper_stage stage)
 435 {
 436         unsigned int line;
 437
 438         if (!mask) {
 439                 for (line = 0; line < epd->height; line++) {
 440                         repaper_one_line(epd, line,
 441                                          &image[line * (epd->width / 8)],
 442                                          0, NULL, stage);
 443                 }
 444         } else {
 445                 for (line = 0; line < epd->height; line++) {
 446                         size_t n = line * epd->width / 8;
 447
 448                         repaper_one_line(epd, line, &image[n], 0, &mask[n],
 449                                          stage);
 450                 }
 451         }
 452 }
 453
 454 static void repaper_frame_fixed_repeat(struct repaper_epd *epd, u8 fixed_value,
 455                                        enum repaper_stage stage)
 456 {
 457         u64 start = local_clock();
 458         u64 end = start + (epd->factored_stage_time * 1000 * 1000);
 459
 460         do {
 461                 repaper_frame_fixed(epd, fixed_value, stage);
 462         } while (local_clock() < end);
 463 }
 464
 465 static void repaper_frame_data_repeat(struct repaper_epd *epd, const u8 *image,
 466                                       const u8 *mask, enum repaper_stage stage)
 467 {
 468         u64 start = local_clock();
 469         u64 end = start + (epd->factored_stage_time * 1000 * 1000);
 470
 471         do {
 472                 repaper_frame_data(epd, image, mask, stage);
 473         } while (local_clock() < end);
 474 }
 475
 476 static void repaper_get_temperature(struct repaper_epd *epd)
 477 {
 478         int ret, temperature = 0;
 479         unsigned int factor10x;
 480
 481         if (!epd->thermal)
 482                 return;
 483
 484         ret = thermal_zone_get_temp(epd->thermal, &temperature);
 485         if (ret) {
 486                 DRM_DEV_ERROR(&epd->spi->dev, "Failed to get temperature (%d)\n", ret);
 487                 return;
 488         }
 489
 490         temperature /= 1000;
 491
 492         if (temperature <= -10)
 493                 factor10x = 170;
 494         else if (temperature <= -5)
 495                 factor10x = 120;
 496         else if (temperature <= 5)
 497                 factor10x = 80;
 498         else if (temperature <= 10)
 499                 factor10x = 40;
 500         else if (temperature <= 15)
 501                 factor10x = 30;
 502         else if (temperature <= 20)
 503                 factor10x = 20;
 504         else if (temperature <= 40)
 505                 factor10x = 10;
 506         else
 507                 factor10x = 7;
 508
 509         epd->factored_stage_time = epd->stage_time * factor10x / 10;
 510 }
 511
 512 static int repaper_fb_dirty(struct drm_framebuffer *fb)
 513 {
 514         struct drm_gem_dma_object *dma_obj = drm_fb_dma_get_gem_obj(fb, 0);
 515         struct repaper_epd *epd = drm_to_epd(fb->dev);
 516         unsigned int dst_pitch = 0;
 517         struct iosys_map dst, vmap;
 518         struct drm_rect clip;
 519         int idx, ret = 0;
 520         u8 *buf = NULL;
 521
 522         if (!drm_dev_enter(fb->dev, &idx))
 523                 return -ENODEV;
 524
 525         /* repaper can't do partial updates */
 526         clip.x1 = 0;
 527         clip.x2 = fb->width;
 528         clip.y1 = 0;
 529         clip.y2 = fb->height;
 530
 531         repaper_get_temperature(epd);
 532
 533         DRM_DEBUG("Flushing [FB:%d] st=%ums\n", fb->base.id,
 534                   epd->factored_stage_time);
 535
 536         buf = kmalloc_array(fb->width, fb->height, GFP_KERNEL);
 537         if (!buf) {
 538                 ret = -ENOMEM;
 539                 goto out_exit;
 540         }
 541
 542         ret = drm_gem_fb_begin_cpu_access(fb, DMA_FROM_DEVICE);
 543         if (ret)
 544                 goto out_free;
 545
 546         iosys_map_set_vaddr(&dst, buf);
 547         iosys_map_set_vaddr(&vmap, dma_obj->vaddr);
 548         drm_fb_xrgb8888_to_mono(&dst, &dst_pitch, &vmap, fb, &clip);
 549
 550         drm_gem_fb_end_cpu_access(fb, DMA_FROM_DEVICE);
 551
 552         if (epd->partial) {
 553                 repaper_frame_data_repeat(epd, buf, epd->current_frame,
 554                                           REPAPER_NORMAL);
 555         } else if (epd->cleared) {
 556                 repaper_frame_data_repeat(epd, epd->current_frame, NULL,
 557                                           REPAPER_COMPENSATE);
 558                 repaper_frame_data_repeat(epd, epd->current_frame, NULL,
 559                                           REPAPER_WHITE);
 560                 repaper_frame_data_repeat(epd, buf, NULL, REPAPER_INVERSE);
 561                 repaper_frame_data_repeat(epd, buf, NULL, REPAPER_NORMAL);
 562
 563                 epd->partial = true;
 564         } else {
 565                 /* Clear display (anything -> white) */
 566                 repaper_frame_fixed_repeat(epd, 0xff, REPAPER_COMPENSATE);
 567                 repaper_frame_fixed_repeat(epd, 0xff, REPAPER_WHITE);
 568                 repaper_frame_fixed_repeat(epd, 0xaa, REPAPER_INVERSE);
 569                 repaper_frame_fixed_repeat(epd, 0xaa, REPAPER_NORMAL);
 570
 571                 /* Assuming a clear (white) screen output an image */
 572                 repaper_frame_fixed_repeat(epd, 0xaa, REPAPER_COMPENSATE);
 573                 repaper_frame_fixed_repeat(epd, 0xaa, REPAPER_WHITE);
 574                 repaper_frame_data_repeat(epd, buf, NULL, REPAPER_INVERSE);
 575                 repaper_frame_data_repeat(epd, buf, NULL, REPAPER_NORMAL);
 576
 577                 epd->cleared = true;
 578                 epd->partial = true;
 579         }
 580
 581         memcpy(epd->current_frame, buf, fb->width * fb->height / 8);
 582
 583         /*
 584          * An extra frame write is needed if pixels are set in the bottom line,
 585          * or else grey lines rises up from the pixels
 586          */
 587         if (epd->pre_border_byte) {
 588                 unsigned int x;
 589
 590                 for (x = 0; x < (fb->width / 8); x++)
 591                         if (buf[x + (fb->width * (fb->height - 1) / 8)]) {
 592                                 repaper_frame_data_repeat(epd, buf,
 593                                                           epd->current_frame,
 594                                                           REPAPER_NORMAL);
 595                                 break;
 596                         }
 597         }
 598
 599 out_free:
 600         kfree(buf);
 601 out_exit:
 602         drm_dev_exit(idx);
 603
 604         return ret;
 605 }
 606
 607 static void power_off(struct repaper_epd *epd)
 608 {
 609         /* Turn off power and all signals */
 610         gpiod_set_value_cansleep(epd->reset, 0);
 611         gpiod_set_value_cansleep(epd->panel_on, 0);
 612         if (epd->border)
 613                 gpiod_set_value_cansleep(epd->border, 0);
 614
 615         /* Ensure SPI MOSI and CLOCK are Low before CS Low */
 616         repaper_spi_mosi_low(epd->spi);
 617
 618         /* Discharge pulse */
 619         gpiod_set_value_cansleep(epd->discharge, 1);
 620         msleep(150);
 621         gpiod_set_value_cansleep(epd->discharge, 0);
 622 }
 623
 624 static enum drm_mode_status repaper_pipe_mode_valid(struct drm_simple_display_pipe *pipe,
 625                                                     const struct drm_display_mode *mode)
 626 {
 627         struct drm_crtc *crtc = &pipe->crtc;
 628         struct repaper_epd *epd = drm_to_epd(crtc->dev);
 629
 630         return drm_crtc_helper_mode_valid_fixed(crtc, mode, epd->mode);
 631 }
 632
 633 static void repaper_pipe_enable(struct drm_simple_display_pipe *pipe,
 634                                 struct drm_crtc_state *crtc_state,
 635                                 struct drm_plane_state *plane_state)
 636 {
 637         struct repaper_epd *epd = drm_to_epd(pipe->crtc.dev);
 638         struct spi_device *spi = epd->spi;
 639         struct device *dev = &spi->dev;
 640         bool dc_ok = false;
 641         int i, ret, idx;
 642
 643         if (!drm_dev_enter(pipe->crtc.dev, &idx))
 644                 return;
 645
 646         DRM_DEBUG_DRIVER("\n");
 647
 648         /* Power up sequence */
 649         gpiod_set_value_cansleep(epd->reset, 0);
 650         gpiod_set_value_cansleep(epd->panel_on, 0);
 651         gpiod_set_value_cansleep(epd->discharge, 0);
 652         if (epd->border)
 653                 gpiod_set_value_cansleep(epd->border, 0);
 654         repaper_spi_mosi_low(spi);
 655         usleep_range(5000, 10000);
 656
 657         gpiod_set_value_cansleep(epd->panel_on, 1);
 658         /*
 659          * This delay comes from the repaper.org userspace driver, it's not
 660          * mentioned in the datasheet.
 661          */
 662         usleep_range(10000, 15000);
 663         gpiod_set_value_cansleep(epd->reset, 1);
 664         if (epd->border)
 665                 gpiod_set_value_cansleep(epd->border, 1);
 666         usleep_range(5000, 10000);
 667         gpiod_set_value_cansleep(epd->reset, 0);
 668         usleep_range(5000, 10000);
 669         gpiod_set_value_cansleep(epd->reset, 1);
 670         usleep_range(5000, 10000);
 671
 672         /* Wait for COG to become ready */
 673         for (i = 100; i > 0; i--) {
 674                 if (!gpiod_get_value_cansleep(epd->busy))
 675                         break;
 676
 677                 usleep_range(10, 100);
 678         }
 679
 680         if (!i) {
 681                 DRM_DEV_ERROR(dev, "timeout waiting for panel to become ready.\n");
 682                 power_off(epd);
 683                 goto out_exit;
 684         }
 685
 686         repaper_read_id(spi);
 687         ret = repaper_read_id(spi);
 688         if (ret != REPAPER_RID_G2_COG_ID) {
 689                 if (ret < 0)
 690                         dev_err(dev, "failed to read chip (%d)\n", ret);
 691                 else
 692                         dev_err(dev, "wrong COG ID 0x%02x\n", ret);
 693                 power_off(epd);
 694                 goto out_exit;
 695         }
 696
 697         /* Disable OE */
 698         repaper_write_val(spi, 0x02, 0x40);
 699
 700         ret = repaper_read_val(spi, 0x0f);
 701         if (ret < 0 || !(ret & 0x80)) {
 702                 if (ret < 0)
 703                         DRM_DEV_ERROR(dev, "failed to read chip (%d)\n", ret);
 704                 else
 705                         DRM_DEV_ERROR(dev, "panel is reported broken\n");
 706                 power_off(epd);
 707                 goto out_exit;
 708         }
 709
 710         /* Power saving mode */
 711         repaper_write_val(spi, 0x0b, 0x02);
 712         /* Channel select */
 713         repaper_write_buf(spi, 0x01, epd->channel_select, 8);
 714         /* High power mode osc */
 715         repaper_write_val(spi, 0x07, 0xd1);
 716         /* Power setting */
 717         repaper_write_val(spi, 0x08, 0x02);
 718         /* Vcom level */
 719         repaper_write_val(spi, 0x09, 0xc2);
 720         /* Power setting */
 721         repaper_write_val(spi, 0x04, 0x03);
 722         /* Driver latch on */
 723         repaper_write_val(spi, 0x03, 0x01);
 724         /* Driver latch off */
 725         repaper_write_val(spi, 0x03, 0x00);
 726         usleep_range(5000, 10000);
 727
 728         /* Start chargepump */
 729         for (i = 0; i < 4; ++i) {
 730                 /* Charge pump positive voltage on - VGH/VDL on */
 731                 repaper_write_val(spi, 0x05, 0x01);
 732                 msleep(240);
 733
 734                 /* Charge pump negative voltage on - VGL/VDL on */
 735                 repaper_write_val(spi, 0x05, 0x03);
 736                 msleep(40);
 737
 738                 /* Charge pump Vcom on - Vcom driver on */
 739                 repaper_write_val(spi, 0x05, 0x0f);
 740                 msleep(40);
 741
 742                 /* check DC/DC */
 743                 ret = repaper_read_val(spi, 0x0f);
 744                 if (ret < 0) {
 745                         DRM_DEV_ERROR(dev, "failed to read chip (%d)\n", ret);
 746                         power_off(epd);
 747                         goto out_exit;
 748                 }
 749
 750                 if (ret & 0x40) {
 751                         dc_ok = true;
 752                         break;
 753                 }
 754         }
 755
 756         if (!dc_ok) {
 757                 DRM_DEV_ERROR(dev, "dc/dc failed\n");
 758                 power_off(epd);
 759                 goto out_exit;
 760         }
 761
 762         /*
 763          * Output enable to disable
 764          * The userspace driver sets this to 0x04, but the datasheet says 0x06
 765          */
 766         repaper_write_val(spi, 0x02, 0x04);
 767
 768         epd->partial = false;
 769 out_exit:
 770         drm_dev_exit(idx);
 771 }
 772
 773 static void repaper_pipe_disable(struct drm_simple_display_pipe *pipe)
 774 {
 775         struct repaper_epd *epd = drm_to_epd(pipe->crtc.dev);
 776         struct spi_device *spi = epd->spi;
 777         unsigned int line;
 778
 779         /*
 780          * This callback is not protected by drm_dev_enter/exit since we want to
 781          * turn off the display on regular driver unload. It's highly unlikely
 782          * that the underlying SPI controller is gone should this be called after
 783          * unplug.
 784          */
 785
 786         DRM_DEBUG_DRIVER("\n");
 787
 788         /* Nothing frame */
 789         for (line = 0; line < epd->height; line++)
 790                 repaper_one_line(epd, 0x7fffu, NULL, 0x00, NULL,
 791                                  REPAPER_COMPENSATE);
 792
 793         /* 2.7" */
 794         if (epd->border) {
 795                 /* Dummy line */
 796                 repaper_one_line(epd, 0x7fffu, NULL, 0x00, NULL,
 797                                  REPAPER_COMPENSATE);
 798                 msleep(25);
 799                 gpiod_set_value_cansleep(epd->border, 0);
 800                 msleep(200);
 801                 gpiod_set_value_cansleep(epd->border, 1);
 802         } else {
 803                 /* Border dummy line */
 804                 repaper_one_line(epd, 0x7fffu, NULL, 0x00, NULL,
 805                                  REPAPER_NORMAL);
 806                 msleep(200);
 807         }
 808
 809         /* not described in datasheet */
 810         repaper_write_val(spi, 0x0b, 0x00);
 811         /* Latch reset turn on */
 812         repaper_write_val(spi, 0x03, 0x01);
 813         /* Power off charge pump Vcom */
 814         repaper_write_val(spi, 0x05, 0x03);
 815         /* Power off charge pump neg voltage */
 816         repaper_write_val(spi, 0x05, 0x01);
 817         msleep(120);
 818         /* Discharge internal */
 819         repaper_write_val(spi, 0x04, 0x80);
 820         /* turn off all charge pumps */
 821         repaper_write_val(spi, 0x05, 0x00);
 822         /* Turn off osc */
 823         repaper_write_val(spi, 0x07, 0x01);
 824         msleep(50);
 825
 826         power_off(epd);
 827 }
 828
 829 static void repaper_pipe_update(struct drm_simple_display_pipe *pipe,
 830                                 struct drm_plane_state *old_state)
 831 {
 832         struct drm_plane_state *state = pipe->plane.state;
 833         struct drm_rect rect;
 834
 835         if (!pipe->crtc.state->active)
 836                 return;
 837
 838         if (drm_atomic_helper_damage_merged(old_state, state, &rect))
 839                 repaper_fb_dirty(state->fb);
 840 }
 841
 842 static const struct drm_simple_display_pipe_funcs repaper_pipe_funcs = {
 843         .mode_valid = repaper_pipe_mode_valid,
 844         .enable = repaper_pipe_enable,
 845         .disable = repaper_pipe_disable,
 846         .update = repaper_pipe_update,
 847 };
 848
 849 static int repaper_connector_get_modes(struct drm_connector *connector)
 850 {
 851         struct repaper_epd *epd = drm_to_epd(connector->dev);
 852
 853         return drm_connector_helper_get_modes_fixed(connector, epd->mode);
 854 }
 855
 856 static const struct drm_connector_helper_funcs repaper_connector_hfuncs = {
 857         .get_modes = repaper_connector_get_modes,
 858 };
 859
 860 static const struct drm_connector_funcs repaper_connector_funcs = {
 861         .reset = drm_atomic_helper_connector_reset,
 862         .fill_modes = drm_helper_probe_single_connector_modes,
 863         .destroy = drm_connector_cleanup,
 864         .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
 865         .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
 866 };
 867
 868 static const struct drm_mode_config_funcs repaper_mode_config_funcs = {
 869         .fb_create = drm_gem_fb_create_with_dirty,
 870         .atomic_check = drm_atomic_helper_check,
 871         .atomic_commit = drm_atomic_helper_commit,
 872 };
 873
 874 static const uint32_t repaper_formats[] = {
 875         DRM_FORMAT_XRGB8888,
 876 };
 877
 878 static const struct drm_display_mode repaper_e1144cs021_mode = {
 879         DRM_SIMPLE_MODE(128, 96, 29, 22),
 880 };
 881
 882 static const u8 repaper_e1144cs021_cs[] = { 0x00, 0x00, 0x00, 0x00,
 883                                             0x00, 0x0f, 0xff, 0x00 };
 884
 885 static const struct drm_display_mode repaper_e1190cs021_mode = {
 886         DRM_SIMPLE_MODE(144, 128, 36, 32),
 887 };
 888
 889 static const u8 repaper_e1190cs021_cs[] = { 0x00, 0x00, 0x00, 0x03,
 890                                             0xfc, 0x00, 0x00, 0xff };
 891
 892 static const struct drm_display_mode repaper_e2200cs021_mode = {
 893         DRM_SIMPLE_MODE(200, 96, 46, 22),
 894 };
 895
 896 static const u8 repaper_e2200cs021_cs[] = { 0x00, 0x00, 0x00, 0x00,
 897                                             0x01, 0xff, 0xe0, 0x00 };
 898
 899 static const struct drm_display_mode repaper_e2271cs021_mode = {
 900         DRM_SIMPLE_MODE(264, 176, 57, 38),
 901 };
 902
 903 static const u8 repaper_e2271cs021_cs[] = { 0x00, 0x00, 0x00, 0x7f,
 904                                             0xff, 0xfe, 0x00, 0x00 };
 905
 906 DEFINE_DRM_GEM_DMA_FOPS(repaper_fops);
 907
 908 static const struct drm_driver repaper_driver = {
 909         .driver_features        = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
 910         .fops                   = &repaper_fops,
 911         DRM_GEM_DMA_DRIVER_OPS_VMAP,
 912         .name                   = "repaper",
 913         .desc                   = "Pervasive Displays RePaper e-ink panels",
 914         .date                   = "20170405",
 915         .major                  = 1,
 916         .minor                  = 0,
 917 };
 918
 919 static const struct of_device_id repaper_of_match[] = {
 920         { .compatible = "pervasive,e1144cs021", .data = (void *)E1144CS021 },
 921         { .compatible = "pervasive,e1190cs021", .data = (void *)E1190CS021 },
 922         { .compatible = "pervasive,e2200cs021", .data = (void *)E2200CS021 },
 923         { .compatible = "pervasive,e2271cs021", .data = (void *)E2271CS021 },
 924         {},
 925 };
 926 MODULE_DEVICE_TABLE(of, repaper_of_match);
 927
 928 static const struct spi_device_id repaper_id[] = {
 929         { "e1144cs021", E1144CS021 },
 930         { "e1190cs021", E1190CS021 },
 931         { "e2200cs021", E2200CS021 },
 932         { "e2271cs021", E2271CS021 },
 933         { },
 934 };
 935 MODULE_DEVICE_TABLE(spi, repaper_id);
 936
 937 static int repaper_probe(struct spi_device *spi)
 938 {
 939         const struct drm_display_mode *mode;
 940         const struct spi_device_id *spi_id;
 941         struct device *dev = &spi->dev;
 942         enum repaper_model model;
 943         const char *thermal_zone;
 944         struct repaper_epd *epd;
 945         size_t line_buffer_size;
 946         struct drm_device *drm;
 947         const void *match;
 948         int ret;
 949
 950         match = device_get_match_data(dev);
 951         if (match) {
 952                 model = (enum repaper_model)match;
 953         } else {
 954                 spi_id = spi_get_device_id(spi);
 955                 model = (enum repaper_model)spi_id->driver_data;
 956         }
 957
 958         /* The SPI device is used to allocate dma memory */
 959         if (!dev->coherent_dma_mask) {
 960                 ret = dma_coerce_mask_and_coherent(dev, DMA_BIT_MASK(32));
 961                 if (ret) {
 962                         dev_warn(dev, "Failed to set dma mask %d\n", ret);
 963                         return ret;
 964                 }
 965         }
 966
 967         epd = devm_drm_dev_alloc(dev, &repaper_driver,
 968                                  struct repaper_epd, drm);
 969         if (IS_ERR(epd))
 970                 return PTR_ERR(epd);
 971
 972         drm = &epd->drm;
 973
 974         ret = drmm_mode_config_init(drm);
 975         if (ret)
 976                 return ret;
 977         drm->mode_config.funcs = &repaper_mode_config_funcs;
 978
 979         epd->spi = spi;
 980
 981         epd->panel_on = devm_gpiod_get(dev, "panel-on", GPIOD_OUT_LOW);
 982         if (IS_ERR(epd->panel_on)) {
 983                 ret = PTR_ERR(epd->panel_on);
 984                 if (ret != -EPROBE_DEFER)
 985                         DRM_DEV_ERROR(dev, "Failed to get gpio 'panel-on'\n");
 986                 return ret;
 987         }
 988
 989         epd->discharge = devm_gpiod_get(dev, "discharge", GPIOD_OUT_LOW);
 990         if (IS_ERR(epd->discharge)) {
 991                 ret = PTR_ERR(epd->discharge);
 992                 if (ret != -EPROBE_DEFER)
 993                         DRM_DEV_ERROR(dev, "Failed to get gpio 'discharge'\n");
 994                 return ret;
 995         }
 996
 997         epd->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
 998         if (IS_ERR(epd->reset)) {
 999                 ret = PTR_ERR(epd->reset);
1000                 if (ret != -EPROBE_DEFER)
1001                         DRM_DEV_ERROR(dev, "Failed to get gpio 'reset'\n");
1002                 return ret;
1003         }
1004
1005         epd->busy = devm_gpiod_get(dev, "busy", GPIOD_IN);
1006         if (IS_ERR(epd->busy)) {
1007                 ret = PTR_ERR(epd->busy);
1008                 if (ret != -EPROBE_DEFER)
1009                         DRM_DEV_ERROR(dev, "Failed to get gpio 'busy'\n");
1010                 return ret;
1011         }
1012
1013         if (!device_property_read_string(dev, "pervasive,thermal-zone",
1014                                          &thermal_zone)) {
1015                 epd->thermal = thermal_zone_get_zone_by_name(thermal_zone);
1016                 if (IS_ERR(epd->thermal)) {
1017                         DRM_DEV_ERROR(dev, "Failed to get thermal zone: %s\n", thermal_zone);
1018                         return PTR_ERR(epd->thermal);
1019                 }
1020         }
1021
1022         switch (model) {
1023         case E1144CS021:
1024                 mode = &repaper_e1144cs021_mode;
1025                 epd->channel_select = repaper_e1144cs021_cs;
1026                 epd->stage_time = 480;
1027                 epd->bytes_per_scan = 96 / 4;
1028                 epd->middle_scan = true; /* data-scan-data */
1029                 epd->pre_border_byte = false;
1030                 epd->border_byte = REPAPER_BORDER_BYTE_ZERO;
1031                 break;
1032
1033         case E1190CS021:
1034                 mode = &repaper_e1190cs021_mode;
1035                 epd->channel_select = repaper_e1190cs021_cs;
1036                 epd->stage_time = 480;
1037                 epd->bytes_per_scan = 128 / 4 / 2;
1038                 epd->middle_scan = false; /* scan-data-scan */
1039                 epd->pre_border_byte = false;
1040                 epd->border_byte = REPAPER_BORDER_BYTE_SET;
1041                 break;
1042
1043         case E2200CS021:
1044                 mode = &repaper_e2200cs021_mode;
1045                 epd->channel_select = repaper_e2200cs021_cs;
1046                 epd->stage_time = 480;
1047                 epd->bytes_per_scan = 96 / 4;
1048                 epd->middle_scan = true; /* data-scan-data */
1049                 epd->pre_border_byte = true;
1050                 epd->border_byte = REPAPER_BORDER_BYTE_NONE;
1051                 break;
1052
1053         case E2271CS021:
1054                 epd->border = devm_gpiod_get(dev, "border", GPIOD_OUT_LOW);
1055                 if (IS_ERR(epd->border)) {
1056                         ret = PTR_ERR(epd->border);
1057                         if (ret != -EPROBE_DEFER)
1058                                 DRM_DEV_ERROR(dev, "Failed to get gpio 'border'\n");
1059                         return ret;
1060                 }
1061
1062                 mode = &repaper_e2271cs021_mode;
1063                 epd->channel_select = repaper_e2271cs021_cs;
1064                 epd->stage_time = 630;
1065                 epd->bytes_per_scan = 176 / 4;
1066                 epd->middle_scan = true; /* data-scan-data */
1067                 epd->pre_border_byte = true;
1068                 epd->border_byte = REPAPER_BORDER_BYTE_NONE;
1069                 break;
1070
1071         default:
1072                 return -ENODEV;
1073         }
1074
1075         epd->mode = mode;
1076         epd->width = mode->hdisplay;
1077         epd->height = mode->vdisplay;
1078         epd->factored_stage_time = epd->stage_time;
1079
1080         line_buffer_size = 2 * epd->width / 8 + epd->bytes_per_scan + 2;
1081         epd->line_buffer = devm_kzalloc(dev, line_buffer_size, GFP_KERNEL);
1082         if (!epd->line_buffer)
1083                 return -ENOMEM;
1084
1085         epd->current_frame = devm_kzalloc(dev, epd->width * epd->height / 8,
1086                                           GFP_KERNEL);
1087         if (!epd->current_frame)
1088                 return -ENOMEM;
1089
1090         drm->mode_config.min_width = mode->hdisplay;
1091         drm->mode_config.max_width = mode->hdisplay;
1092         drm->mode_config.min_height = mode->vdisplay;
1093         drm->mode_config.max_height = mode->vdisplay;
1094
1095         drm_connector_helper_add(&epd->connector, &repaper_connector_hfuncs);
1096         ret = drm_connector_init(drm, &epd->connector, &repaper_connector_funcs,
1097                                  DRM_MODE_CONNECTOR_SPI);
1098         if (ret)
1099                 return ret;
1100
1101         ret = drm_simple_display_pipe_init(drm, &epd->pipe, &repaper_pipe_funcs,
1102                                            repaper_formats, ARRAY_SIZE(repaper_formats),
1103                                            NULL, &epd->connector);
1104         if (ret)
1105                 return ret;
1106
1107         drm_mode_config_reset(drm);
1108
1109         ret = drm_dev_register(drm, 0);
1110         if (ret)
1111                 return ret;
1112
1113         spi_set_drvdata(spi, drm);
1114
1115         DRM_DEBUG_DRIVER("SPI speed: %uMHz\n", spi->max_speed_hz / 1000000);
1116
1117         drm_fbdev_generic_setup(drm, 0);
1118
1119         return 0;
1120 }
1121
1122 static void repaper_remove(struct spi_device *spi)
1123 {
1124         struct drm_device *drm = spi_get_drvdata(spi);
1125
1126         drm_dev_unplug(drm);
1127         drm_atomic_helper_shutdown(drm);
1128 }
1129
1130 static void repaper_shutdown(struct spi_device *spi)
1131 {
1132         drm_atomic_helper_shutdown(spi_get_drvdata(spi));
1133 }
1134
1135 static struct spi_driver repaper_spi_driver = {
1136         .driver = {
1137                 .name = "repaper",
1138                 .of_match_table = repaper_of_match,
1139         },
1140         .id_table = repaper_id,
1141         .probe = repaper_probe,
1142         .remove = repaper_remove,
1143         .shutdown = repaper_shutdown,
1144 };
1145 module_spi_driver(repaper_spi_driver);
1146
1147 MODULE_DESCRIPTION("Pervasive Displays RePaper DRM driver");
1148 MODULE_AUTHOR("Noralf Trønnes");
1149 MODULE_LICENSE("GPL");