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/dma-buf.h>
  18 #include <linux/gpio/consumer.h>
  19 #include <linux/module.h>
  20 #include <linux/property.h>
  21 #include <linux/sched/clock.h>
  22 #include <linux/spi/spi.h>
  23 #include <linux/thermal.h>
  24
  25 #include <drm/drm_atomic_helper.h>
  26 #include <drm/drm_connector.h>
  27 #include <drm/drm_damage_helper.h>
  28 #include <drm/drm_drv.h>
  29 #include <drm/drm_fb_cma_helper.h>
  30 #include <drm/drm_fb_helper.h>
  31 #include <drm/drm_format_helper.h>
  32 #include <drm/drm_gem_cma_helper.h>
  33 #include <drm/drm_gem_framebuffer_helper.h>
  34 #include <drm/drm_managed.h>
  35 #include <drm/drm_modes.h>
  36 #include <drm/drm_rect.h>
  37 #include <drm/drm_probe_helper.h>
  38 #include <drm/drm_simple_kms_helper.h>
  39
  40 #define REPAPER_RID_G2_COG_ID   0x12
  41
  42 enum repaper_model {
  43         /* 0 is reserved to avoid clashing with NULL */
  44         E1144CS021 = 1,
  45         E1190CS021,
  46         E2200CS021,
  47         E2271CS021,
  48 };
  49
  50 enum repaper_stage {         /* Image pixel -> Display pixel */
  51         REPAPER_COMPENSATE,  /* B -> W, W -> B (Current Image) */
  52         REPAPER_WHITE,       /* B -> N, W -> W (Current Image) */
  53         REPAPER_INVERSE,     /* B -> N, W -> B (New Image) */
  54         REPAPER_NORMAL       /* B -> B, W -> W (New Image) */
  55 };
  56
  57 enum repaper_epd_border_byte {
  58         REPAPER_BORDER_BYTE_NONE,
  59         REPAPER_BORDER_BYTE_ZERO,
  60         REPAPER_BORDER_BYTE_SET,
  61 };
  62
  63 struct repaper_epd {
  64         struct drm_device drm;
  65         struct drm_simple_display_pipe pipe;
  66         const struct drm_display_mode *mode;
  67         struct drm_connector connector;
  68         struct spi_device *spi;
  69
  70         struct gpio_desc *panel_on;
  71         struct gpio_desc *border;
  72         struct gpio_desc *discharge;
  73         struct gpio_desc *reset;
  74         struct gpio_desc *busy;
  75
  76         struct thermal_zone_device *thermal;
  77
  78         unsigned int height;
  79         unsigned int width;
  80         unsigned int bytes_per_scan;
  81         const u8 *channel_select;
  82         unsigned int stage_time;
  83         unsigned int factored_stage_time;
  84         bool middle_scan;
  85         bool pre_border_byte;
  86         enum repaper_epd_border_byte border_byte;
  87
  88         u8 *line_buffer;
  89         void *current_frame;
  90
  91         bool enabled;
  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 void repaper_gray8_to_mono_reversed(u8 *buf, u32 width, u32 height)
 513 {
 514         u8 *gray8 = buf, *mono = buf;
 515         int y, xb, i;
 516
 517         for (y = 0; y < height; y++)
 518                 for (xb = 0; xb < width / 8; xb++) {
 519                         u8 byte = 0x00;
 520
 521                         for (i = 0; i < 8; i++) {
 522                                 int x = xb * 8 + i;
 523
 524                                 byte >>= 1;
 525                                 if (gray8[y * width + x] >> 7)
 526                                         byte |= BIT(7);
 527                         }
 528                         *mono++ = byte;
 529                 }
 530 }
 531
 532 static int repaper_fb_dirty(struct drm_framebuffer *fb)
 533 {
 534         struct drm_gem_cma_object *cma_obj = drm_fb_cma_get_gem_obj(fb, 0);
 535         struct dma_buf_attachment *import_attach = cma_obj->base.import_attach;
 536         struct repaper_epd *epd = drm_to_epd(fb->dev);
 537         struct drm_rect clip;
 538         int idx, ret = 0;
 539         u8 *buf = NULL;
 540
 541         if (!epd->enabled)
 542                 return 0;
 543
 544         if (!drm_dev_enter(fb->dev, &idx))
 545                 return -ENODEV;
 546
 547         /* repaper can't do partial updates */
 548         clip.x1 = 0;
 549         clip.x2 = fb->width;
 550         clip.y1 = 0;
 551         clip.y2 = fb->height;
 552
 553         repaper_get_temperature(epd);
 554
 555         DRM_DEBUG("Flushing [FB:%d] st=%ums\n", fb->base.id,
 556                   epd->factored_stage_time);
 557
 558         buf = kmalloc_array(fb->width, fb->height, GFP_KERNEL);
 559         if (!buf) {
 560                 ret = -ENOMEM;
 561                 goto out_exit;
 562         }
 563
 564         if (import_attach) {
 565                 ret = dma_buf_begin_cpu_access(import_attach->dmabuf,
 566                                                DMA_FROM_DEVICE);
 567                 if (ret)
 568                         goto out_free;
 569         }
 570
 571         drm_fb_xrgb8888_to_gray8(buf, cma_obj->vaddr, fb, &clip);
 572
 573         if (import_attach) {
 574                 ret = dma_buf_end_cpu_access(import_attach->dmabuf,
 575                                              DMA_FROM_DEVICE);
 576                 if (ret)
 577                         goto out_free;
 578         }
 579
 580         repaper_gray8_to_mono_reversed(buf, fb->width, fb->height);
 581
 582         if (epd->partial) {
 583                 repaper_frame_data_repeat(epd, buf, epd->current_frame,
 584                                           REPAPER_NORMAL);
 585         } else if (epd->cleared) {
 586                 repaper_frame_data_repeat(epd, epd->current_frame, NULL,
 587                                           REPAPER_COMPENSATE);
 588                 repaper_frame_data_repeat(epd, epd->current_frame, NULL,
 589                                           REPAPER_WHITE);
 590                 repaper_frame_data_repeat(epd, buf, NULL, REPAPER_INVERSE);
 591                 repaper_frame_data_repeat(epd, buf, NULL, REPAPER_NORMAL);
 592
 593                 epd->partial = true;
 594         } else {
 595                 /* Clear display (anything -> white) */
 596                 repaper_frame_fixed_repeat(epd, 0xff, REPAPER_COMPENSATE);
 597                 repaper_frame_fixed_repeat(epd, 0xff, REPAPER_WHITE);
 598                 repaper_frame_fixed_repeat(epd, 0xaa, REPAPER_INVERSE);
 599                 repaper_frame_fixed_repeat(epd, 0xaa, REPAPER_NORMAL);
 600
 601                 /* Assuming a clear (white) screen output an image */
 602                 repaper_frame_fixed_repeat(epd, 0xaa, REPAPER_COMPENSATE);
 603                 repaper_frame_fixed_repeat(epd, 0xaa, REPAPER_WHITE);
 604                 repaper_frame_data_repeat(epd, buf, NULL, REPAPER_INVERSE);
 605                 repaper_frame_data_repeat(epd, buf, NULL, REPAPER_NORMAL);
 606
 607                 epd->cleared = true;
 608                 epd->partial = true;
 609         }
 610
 611         memcpy(epd->current_frame, buf, fb->width * fb->height / 8);
 612
 613         /*
 614          * An extra frame write is needed if pixels are set in the bottom line,
 615          * or else grey lines rises up from the pixels
 616          */
 617         if (epd->pre_border_byte) {
 618                 unsigned int x;
 619
 620                 for (x = 0; x < (fb->width / 8); x++)
 621                         if (buf[x + (fb->width * (fb->height - 1) / 8)]) {
 622                                 repaper_frame_data_repeat(epd, buf,
 623                                                           epd->current_frame,
 624                                                           REPAPER_NORMAL);
 625                                 break;
 626                         }
 627         }
 628
 629 out_free:
 630         kfree(buf);
 631 out_exit:
 632         drm_dev_exit(idx);
 633
 634         return ret;
 635 }
 636
 637 static void power_off(struct repaper_epd *epd)
 638 {
 639         /* Turn off power and all signals */
 640         gpiod_set_value_cansleep(epd->reset, 0);
 641         gpiod_set_value_cansleep(epd->panel_on, 0);
 642         if (epd->border)
 643                 gpiod_set_value_cansleep(epd->border, 0);
 644
 645         /* Ensure SPI MOSI and CLOCK are Low before CS Low */
 646         repaper_spi_mosi_low(epd->spi);
 647
 648         /* Discharge pulse */
 649         gpiod_set_value_cansleep(epd->discharge, 1);
 650         msleep(150);
 651         gpiod_set_value_cansleep(epd->discharge, 0);
 652 }
 653
 654 static void repaper_pipe_enable(struct drm_simple_display_pipe *pipe,
 655                                 struct drm_crtc_state *crtc_state,
 656                                 struct drm_plane_state *plane_state)
 657 {
 658         struct repaper_epd *epd = drm_to_epd(pipe->crtc.dev);
 659         struct spi_device *spi = epd->spi;
 660         struct device *dev = &spi->dev;
 661         bool dc_ok = false;
 662         int i, ret, idx;
 663
 664         if (!drm_dev_enter(pipe->crtc.dev, &idx))
 665                 return;
 666
 667         DRM_DEBUG_DRIVER("\n");
 668
 669         /* Power up sequence */
 670         gpiod_set_value_cansleep(epd->reset, 0);
 671         gpiod_set_value_cansleep(epd->panel_on, 0);
 672         gpiod_set_value_cansleep(epd->discharge, 0);
 673         if (epd->border)
 674                 gpiod_set_value_cansleep(epd->border, 0);
 675         repaper_spi_mosi_low(spi);
 676         usleep_range(5000, 10000);
 677
 678         gpiod_set_value_cansleep(epd->panel_on, 1);
 679         /*
 680          * This delay comes from the repaper.org userspace driver, it's not
 681          * mentioned in the datasheet.
 682          */
 683         usleep_range(10000, 15000);
 684         gpiod_set_value_cansleep(epd->reset, 1);
 685         if (epd->border)
 686                 gpiod_set_value_cansleep(epd->border, 1);
 687         usleep_range(5000, 10000);
 688         gpiod_set_value_cansleep(epd->reset, 0);
 689         usleep_range(5000, 10000);
 690         gpiod_set_value_cansleep(epd->reset, 1);
 691         usleep_range(5000, 10000);
 692
 693         /* Wait for COG to become ready */
 694         for (i = 100; i > 0; i--) {
 695                 if (!gpiod_get_value_cansleep(epd->busy))
 696                         break;
 697
 698                 usleep_range(10, 100);
 699         }
 700
 701         if (!i) {
 702                 DRM_DEV_ERROR(dev, "timeout waiting for panel to become ready.\n");
 703                 power_off(epd);
 704                 goto out_exit;
 705         }
 706
 707         repaper_read_id(spi);
 708         ret = repaper_read_id(spi);
 709         if (ret != REPAPER_RID_G2_COG_ID) {
 710                 if (ret < 0)
 711                         dev_err(dev, "failed to read chip (%d)\n", ret);
 712                 else
 713                         dev_err(dev, "wrong COG ID 0x%02x\n", ret);
 714                 power_off(epd);
 715                 goto out_exit;
 716         }
 717
 718         /* Disable OE */
 719         repaper_write_val(spi, 0x02, 0x40);
 720
 721         ret = repaper_read_val(spi, 0x0f);
 722         if (ret < 0 || !(ret & 0x80)) {
 723                 if (ret < 0)
 724                         DRM_DEV_ERROR(dev, "failed to read chip (%d)\n", ret);
 725                 else
 726                         DRM_DEV_ERROR(dev, "panel is reported broken\n");
 727                 power_off(epd);
 728                 goto out_exit;
 729         }
 730
 731         /* Power saving mode */
 732         repaper_write_val(spi, 0x0b, 0x02);
 733         /* Channel select */
 734         repaper_write_buf(spi, 0x01, epd->channel_select, 8);
 735         /* High power mode osc */
 736         repaper_write_val(spi, 0x07, 0xd1);
 737         /* Power setting */
 738         repaper_write_val(spi, 0x08, 0x02);
 739         /* Vcom level */
 740         repaper_write_val(spi, 0x09, 0xc2);
 741         /* Power setting */
 742         repaper_write_val(spi, 0x04, 0x03);
 743         /* Driver latch on */
 744         repaper_write_val(spi, 0x03, 0x01);
 745         /* Driver latch off */
 746         repaper_write_val(spi, 0x03, 0x00);
 747         usleep_range(5000, 10000);
 748
 749         /* Start chargepump */
 750         for (i = 0; i < 4; ++i) {
 751                 /* Charge pump positive voltage on - VGH/VDL on */
 752                 repaper_write_val(spi, 0x05, 0x01);
 753                 msleep(240);
 754
 755                 /* Charge pump negative voltage on - VGL/VDL on */
 756                 repaper_write_val(spi, 0x05, 0x03);
 757                 msleep(40);
 758
 759                 /* Charge pump Vcom on - Vcom driver on */
 760                 repaper_write_val(spi, 0x05, 0x0f);
 761                 msleep(40);
 762
 763                 /* check DC/DC */
 764                 ret = repaper_read_val(spi, 0x0f);
 765                 if (ret < 0) {
 766                         DRM_DEV_ERROR(dev, "failed to read chip (%d)\n", ret);
 767                         power_off(epd);
 768                         goto out_exit;
 769                 }
 770
 771                 if (ret & 0x40) {
 772                         dc_ok = true;
 773                         break;
 774                 }
 775         }
 776
 777         if (!dc_ok) {
 778                 DRM_DEV_ERROR(dev, "dc/dc failed\n");
 779                 power_off(epd);
 780                 goto out_exit;
 781         }
 782
 783         /*
 784          * Output enable to disable
 785          * The userspace driver sets this to 0x04, but the datasheet says 0x06
 786          */
 787         repaper_write_val(spi, 0x02, 0x04);
 788
 789         epd->enabled = true;
 790         epd->partial = false;
 791 out_exit:
 792         drm_dev_exit(idx);
 793 }
 794
 795 static void repaper_pipe_disable(struct drm_simple_display_pipe *pipe)
 796 {
 797         struct repaper_epd *epd = drm_to_epd(pipe->crtc.dev);
 798         struct spi_device *spi = epd->spi;
 799         unsigned int line;
 800
 801         /*
 802          * This callback is not protected by drm_dev_enter/exit since we want to
 803          * turn off the display on regular driver unload. It's highly unlikely
 804          * that the underlying SPI controller is gone should this be called after
 805          * unplug.
 806          */
 807
 808         if (!epd->enabled)
 809                 return;
 810
 811         DRM_DEBUG_DRIVER("\n");
 812
 813         epd->enabled = false;
 814
 815         /* Nothing frame */
 816         for (line = 0; line < epd->height; line++)
 817                 repaper_one_line(epd, 0x7fffu, NULL, 0x00, NULL,
 818                                  REPAPER_COMPENSATE);
 819
 820         /* 2.7" */
 821         if (epd->border) {
 822                 /* Dummy line */
 823                 repaper_one_line(epd, 0x7fffu, NULL, 0x00, NULL,
 824                                  REPAPER_COMPENSATE);
 825                 msleep(25);
 826                 gpiod_set_value_cansleep(epd->border, 0);
 827                 msleep(200);
 828                 gpiod_set_value_cansleep(epd->border, 1);
 829         } else {
 830                 /* Border dummy line */
 831                 repaper_one_line(epd, 0x7fffu, NULL, 0x00, NULL,
 832                                  REPAPER_NORMAL);
 833                 msleep(200);
 834         }
 835
 836         /* not described in datasheet */
 837         repaper_write_val(spi, 0x0b, 0x00);
 838         /* Latch reset turn on */
 839         repaper_write_val(spi, 0x03, 0x01);
 840         /* Power off charge pump Vcom */
 841         repaper_write_val(spi, 0x05, 0x03);
 842         /* Power off charge pump neg voltage */
 843         repaper_write_val(spi, 0x05, 0x01);
 844         msleep(120);
 845         /* Discharge internal */
 846         repaper_write_val(spi, 0x04, 0x80);
 847         /* turn off all charge pumps */
 848         repaper_write_val(spi, 0x05, 0x00);
 849         /* Turn off osc */
 850         repaper_write_val(spi, 0x07, 0x01);
 851         msleep(50);
 852
 853         power_off(epd);
 854 }
 855
 856 static void repaper_pipe_update(struct drm_simple_display_pipe *pipe,
 857                                 struct drm_plane_state *old_state)
 858 {
 859         struct drm_plane_state *state = pipe->plane.state;
 860         struct drm_rect rect;
 861
 862         if (drm_atomic_helper_damage_merged(old_state, state, &rect))
 863                 repaper_fb_dirty(state->fb);
 864 }
 865
 866 static const struct drm_simple_display_pipe_funcs repaper_pipe_funcs = {
 867         .enable = repaper_pipe_enable,
 868         .disable = repaper_pipe_disable,
 869         .update = repaper_pipe_update,
 870         .prepare_fb = drm_gem_fb_simple_display_pipe_prepare_fb,
 871 };
 872
 873 static int repaper_connector_get_modes(struct drm_connector *connector)
 874 {
 875         struct repaper_epd *epd = drm_to_epd(connector->dev);
 876         struct drm_display_mode *mode;
 877
 878         mode = drm_mode_duplicate(connector->dev, epd->mode);
 879         if (!mode) {
 880                 DRM_ERROR("Failed to duplicate mode\n");
 881                 return 0;
 882         }
 883
 884         drm_mode_set_name(mode);
 885         mode->type |= DRM_MODE_TYPE_PREFERRED;
 886         drm_mode_probed_add(connector, mode);
 887
 888         connector->display_info.width_mm = mode->width_mm;
 889         connector->display_info.height_mm = mode->height_mm;
 890
 891         return 1;
 892 }
 893
 894 static const struct drm_connector_helper_funcs repaper_connector_hfuncs = {
 895         .get_modes = repaper_connector_get_modes,
 896 };
 897
 898 static const struct drm_connector_funcs repaper_connector_funcs = {
 899         .reset = drm_atomic_helper_connector_reset,
 900         .fill_modes = drm_helper_probe_single_connector_modes,
 901         .destroy = drm_connector_cleanup,
 902         .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
 903         .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
 904 };
 905
 906 static const struct drm_mode_config_funcs repaper_mode_config_funcs = {
 907         .fb_create = drm_gem_fb_create_with_dirty,
 908         .atomic_check = drm_atomic_helper_check,
 909         .atomic_commit = drm_atomic_helper_commit,
 910 };
 911
 912 static const uint32_t repaper_formats[] = {
 913         DRM_FORMAT_XRGB8888,
 914 };
 915
 916 static const struct drm_display_mode repaper_e1144cs021_mode = {
 917         DRM_SIMPLE_MODE(128, 96, 29, 22),
 918 };
 919
 920 static const u8 repaper_e1144cs021_cs[] = { 0x00, 0x00, 0x00, 0x00,
 921                                             0x00, 0x0f, 0xff, 0x00 };
 922
 923 static const struct drm_display_mode repaper_e1190cs021_mode = {
 924         DRM_SIMPLE_MODE(144, 128, 36, 32),
 925 };
 926
 927 static const u8 repaper_e1190cs021_cs[] = { 0x00, 0x00, 0x00, 0x03,
 928                                             0xfc, 0x00, 0x00, 0xff };
 929
 930 static const struct drm_display_mode repaper_e2200cs021_mode = {
 931         DRM_SIMPLE_MODE(200, 96, 46, 22),
 932 };
 933
 934 static const u8 repaper_e2200cs021_cs[] = { 0x00, 0x00, 0x00, 0x00,
 935                                             0x01, 0xff, 0xe0, 0x00 };
 936
 937 static const struct drm_display_mode repaper_e2271cs021_mode = {
 938         DRM_SIMPLE_MODE(264, 176, 57, 38),
 939 };
 940
 941 static const u8 repaper_e2271cs021_cs[] = { 0x00, 0x00, 0x00, 0x7f,
 942                                             0xff, 0xfe, 0x00, 0x00 };
 943
 944 DEFINE_DRM_GEM_CMA_FOPS(repaper_fops);
 945
 946 static struct drm_driver repaper_driver = {
 947         .driver_features        = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
 948         .fops                   = &repaper_fops,
 949         DRM_GEM_CMA_VMAP_DRIVER_OPS,
 950         .name                   = "repaper",
 951         .desc                   = "Pervasive Displays RePaper e-ink panels",
 952         .date                   = "20170405",
 953         .major                  = 1,
 954         .minor                  = 0,
 955 };
 956
 957 static const struct of_device_id repaper_of_match[] = {
 958         { .compatible = "pervasive,e1144cs021", .data = (void *)E1144CS021 },
 959         { .compatible = "pervasive,e1190cs021", .data = (void *)E1190CS021 },
 960         { .compatible = "pervasive,e2200cs021", .data = (void *)E2200CS021 },
 961         { .compatible = "pervasive,e2271cs021", .data = (void *)E2271CS021 },
 962         {},
 963 };
 964 MODULE_DEVICE_TABLE(of, repaper_of_match);
 965
 966 static const struct spi_device_id repaper_id[] = {
 967         { "e1144cs021", E1144CS021 },
 968         { "e1190cs021", E1190CS021 },
 969         { "e2200cs021", E2200CS021 },
 970         { "e2271cs021", E2271CS021 },
 971         { },
 972 };
 973 MODULE_DEVICE_TABLE(spi, repaper_id);
 974
 975 static int repaper_probe(struct spi_device *spi)
 976 {
 977         const struct drm_display_mode *mode;
 978         const struct spi_device_id *spi_id;
 979         struct device *dev = &spi->dev;
 980         enum repaper_model model;
 981         const char *thermal_zone;
 982         struct repaper_epd *epd;
 983         size_t line_buffer_size;
 984         struct drm_device *drm;
 985         const void *match;
 986         int ret;
 987
 988         match = device_get_match_data(dev);
 989         if (match) {
 990                 model = (enum repaper_model)match;
 991         } else {
 992                 spi_id = spi_get_device_id(spi);
 993                 model = (enum repaper_model)spi_id->driver_data;
 994         }
 995
 996         /* The SPI device is used to allocate dma memory */
 997         if (!dev->coherent_dma_mask) {
 998                 ret = dma_coerce_mask_and_coherent(dev, DMA_BIT_MASK(32));
 999                 if (ret) {
1000                         dev_warn(dev, "Failed to set dma mask %d\n", ret);
1001                         return ret;
1002                 }
1003         }
1004
1005         epd = devm_drm_dev_alloc(dev, &repaper_driver,
1006                                  struct repaper_epd, drm);
1007         if (IS_ERR(epd))
1008                 return PTR_ERR(epd);
1009
1010         drm = &epd->drm;
1011
1012         ret = drmm_mode_config_init(drm);
1013         if (ret)
1014                 return ret;
1015         drm->mode_config.funcs = &repaper_mode_config_funcs;
1016
1017         epd->spi = spi;
1018
1019         epd->panel_on = devm_gpiod_get(dev, "panel-on", GPIOD_OUT_LOW);
1020         if (IS_ERR(epd->panel_on)) {
1021                 ret = PTR_ERR(epd->panel_on);
1022                 if (ret != -EPROBE_DEFER)
1023                         DRM_DEV_ERROR(dev, "Failed to get gpio 'panel-on'\n");
1024                 return ret;
1025         }
1026
1027         epd->discharge = devm_gpiod_get(dev, "discharge", GPIOD_OUT_LOW);
1028         if (IS_ERR(epd->discharge)) {
1029                 ret = PTR_ERR(epd->discharge);
1030                 if (ret != -EPROBE_DEFER)
1031                         DRM_DEV_ERROR(dev, "Failed to get gpio 'discharge'\n");
1032                 return ret;
1033         }
1034
1035         epd->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
1036         if (IS_ERR(epd->reset)) {
1037                 ret = PTR_ERR(epd->reset);
1038                 if (ret != -EPROBE_DEFER)
1039                         DRM_DEV_ERROR(dev, "Failed to get gpio 'reset'\n");
1040                 return ret;
1041         }
1042
1043         epd->busy = devm_gpiod_get(dev, "busy", GPIOD_IN);
1044         if (IS_ERR(epd->busy)) {
1045                 ret = PTR_ERR(epd->busy);
1046                 if (ret != -EPROBE_DEFER)
1047                         DRM_DEV_ERROR(dev, "Failed to get gpio 'busy'\n");
1048                 return ret;
1049         }
1050
1051         if (!device_property_read_string(dev, "pervasive,thermal-zone",
1052                                          &thermal_zone)) {
1053                 epd->thermal = thermal_zone_get_zone_by_name(thermal_zone);
1054                 if (IS_ERR(epd->thermal)) {
1055                         DRM_DEV_ERROR(dev, "Failed to get thermal zone: %s\n", thermal_zone);
1056                         return PTR_ERR(epd->thermal);
1057                 }
1058         }
1059
1060         switch (model) {
1061         case E1144CS021:
1062                 mode = &repaper_e1144cs021_mode;
1063                 epd->channel_select = repaper_e1144cs021_cs;
1064                 epd->stage_time = 480;
1065                 epd->bytes_per_scan = 96 / 4;
1066                 epd->middle_scan = true; /* data-scan-data */
1067                 epd->pre_border_byte = false;
1068                 epd->border_byte = REPAPER_BORDER_BYTE_ZERO;
1069                 break;
1070
1071         case E1190CS021:
1072                 mode = &repaper_e1190cs021_mode;
1073                 epd->channel_select = repaper_e1190cs021_cs;
1074                 epd->stage_time = 480;
1075                 epd->bytes_per_scan = 128 / 4 / 2;
1076                 epd->middle_scan = false; /* scan-data-scan */
1077                 epd->pre_border_byte = false;
1078                 epd->border_byte = REPAPER_BORDER_BYTE_SET;
1079                 break;
1080
1081         case E2200CS021:
1082                 mode = &repaper_e2200cs021_mode;
1083                 epd->channel_select = repaper_e2200cs021_cs;
1084                 epd->stage_time = 480;
1085                 epd->bytes_per_scan = 96 / 4;
1086                 epd->middle_scan = true; /* data-scan-data */
1087                 epd->pre_border_byte = true;
1088                 epd->border_byte = REPAPER_BORDER_BYTE_NONE;
1089                 break;
1090
1091         case E2271CS021:
1092                 epd->border = devm_gpiod_get(dev, "border", GPIOD_OUT_LOW);
1093                 if (IS_ERR(epd->border)) {
1094                         ret = PTR_ERR(epd->border);
1095                         if (ret != -EPROBE_DEFER)
1096                                 DRM_DEV_ERROR(dev, "Failed to get gpio 'border'\n");
1097                         return ret;
1098                 }
1099
1100                 mode = &repaper_e2271cs021_mode;
1101                 epd->channel_select = repaper_e2271cs021_cs;
1102                 epd->stage_time = 630;
1103                 epd->bytes_per_scan = 176 / 4;
1104                 epd->middle_scan = true; /* data-scan-data */
1105                 epd->pre_border_byte = true;
1106                 epd->border_byte = REPAPER_BORDER_BYTE_NONE;
1107                 break;
1108
1109         default:
1110                 return -ENODEV;
1111         }
1112
1113         epd->mode = mode;
1114         epd->width = mode->hdisplay;
1115         epd->height = mode->vdisplay;
1116         epd->factored_stage_time = epd->stage_time;
1117
1118         line_buffer_size = 2 * epd->width / 8 + epd->bytes_per_scan + 2;
1119         epd->line_buffer = devm_kzalloc(dev, line_buffer_size, GFP_KERNEL);
1120         if (!epd->line_buffer)
1121                 return -ENOMEM;
1122
1123         epd->current_frame = devm_kzalloc(dev, epd->width * epd->height / 8,
1124                                           GFP_KERNEL);
1125         if (!epd->current_frame)
1126                 return -ENOMEM;
1127
1128         drm->mode_config.min_width = mode->hdisplay;
1129         drm->mode_config.max_width = mode->hdisplay;
1130         drm->mode_config.min_height = mode->vdisplay;
1131         drm->mode_config.max_height = mode->vdisplay;
1132
1133         drm_connector_helper_add(&epd->connector, &repaper_connector_hfuncs);
1134         ret = drm_connector_init(drm, &epd->connector, &repaper_connector_funcs,
1135                                  DRM_MODE_CONNECTOR_SPI);
1136         if (ret)
1137                 return ret;
1138
1139         ret = drm_simple_display_pipe_init(drm, &epd->pipe, &repaper_pipe_funcs,
1140                                            repaper_formats, ARRAY_SIZE(repaper_formats),
1141                                            NULL, &epd->connector);
1142         if (ret)
1143                 return ret;
1144
1145         drm_mode_config_reset(drm);
1146
1147         ret = drm_dev_register(drm, 0);
1148         if (ret)
1149                 return ret;
1150
1151         spi_set_drvdata(spi, drm);
1152
1153         DRM_DEBUG_DRIVER("SPI speed: %uMHz\n", spi->max_speed_hz / 1000000);
1154
1155         drm_fbdev_generic_setup(drm, 0);
1156
1157         return 0;
1158 }
1159
1160 static int repaper_remove(struct spi_device *spi)
1161 {
1162         struct drm_device *drm = spi_get_drvdata(spi);
1163
1164         drm_dev_unplug(drm);
1165         drm_atomic_helper_shutdown(drm);
1166
1167         return 0;
1168 }
1169
1170 static void repaper_shutdown(struct spi_device *spi)
1171 {
1172         drm_atomic_helper_shutdown(spi_get_drvdata(spi));
1173 }
1174
1175 static struct spi_driver repaper_spi_driver = {
1176         .driver = {
1177                 .name = "repaper",
1178                 .of_match_table = repaper_of_match,
1179         },
1180         .id_table = repaper_id,
1181         .probe = repaper_probe,
1182         .remove = repaper_remove,
1183         .shutdown = repaper_shutdown,
1184 };
1185 module_spi_driver(repaper_spi_driver);
1186
1187 MODULE_DESCRIPTION("Pervasive Displays RePaper DRM driver");
1188 MODULE_AUTHOR("Noralf Trønnes");
1189 MODULE_LICENSE("GPL");