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