drivers/gpu/drm/tinydrm/repaper.c

   1 /*
   2  * DRM driver for Pervasive Displays RePaper branded e-ink panels
   3  *
   4  * Copyright 2013-2017 Pervasive Displays, Inc.
   5  * Copyright 2017 Noralf Trønnes
   6  *
   7  * The driver supports:
   8  * Material Film: Aurora Mb (V231)
   9  * Driver IC: G2 (eTC)
  10  *
  11  * The controller code was taken from the userspace driver:
  12  * https://github.com/repaper/gratis
  13  *
  14  * This program is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  */
  19
  20 #include <linux/delay.h>
  21 #include <linux/dma-buf.h>
  22 #include <linux/gpio/consumer.h>
  23 #include <linux/module.h>
  24 #include <linux/of_device.h>
  25 #include <linux/sched/clock.h>
  26 #include <linux/spi/spi.h>
  27 #include <linux/thermal.h>
  28
  29 #include <drm/drm_fb_cma_helper.h>
  30 #include <drm/drm_gem_cma_helper.h>
  31 #include <drm/drm_gem_framebuffer_helper.h>
  32 #include <drm/tinydrm/tinydrm.h>
  33 #include <drm/tinydrm/tinydrm-helpers.h>
  34
  35 #define REPAPER_RID_G2_COG_ID   0x12
  36
  37 enum repaper_model {
  38         E1144CS021 = 1,
  39         E1190CS021,
  40         E2200CS021,
  41         E2271CS021,
  42 };
  43
  44 enum repaper_stage {         /* Image pixel -> Display pixel */
  45         REPAPER_COMPENSATE,  /* B -> W, W -> B (Current Image) */
  46         REPAPER_WHITE,       /* B -> N, W -> W (Current Image) */
  47         REPAPER_INVERSE,     /* B -> N, W -> B (New Image) */
  48         REPAPER_NORMAL       /* B -> B, W -> W (New Image) */
  49 };
  50
  51 enum repaper_epd_border_byte {
  52         REPAPER_BORDER_BYTE_NONE,
  53         REPAPER_BORDER_BYTE_ZERO,
  54         REPAPER_BORDER_BYTE_SET,
  55 };
  56
  57 struct repaper_epd {
  58         struct tinydrm_device tinydrm;
  59         struct spi_device *spi;
  60
  61         struct gpio_desc *panel_on;
  62         struct gpio_desc *border;
  63         struct gpio_desc *discharge;
  64         struct gpio_desc *reset;
  65         struct gpio_desc *busy;
  66
  67         struct thermal_zone_device *thermal;
  68
  69         unsigned int height;
  70         unsigned int width;
  71         unsigned int bytes_per_scan;
  72         const u8 *channel_select;
  73         unsigned int stage_time;
  74         unsigned int factored_stage_time;
  75         bool middle_scan;
  76         bool pre_border_byte;
  77         enum repaper_epd_border_byte border_byte;
  78
  79         u8 *line_buffer;
  80         void *current_frame;
  81
  82         bool enabled;
  83         bool cleared;
  84         bool partial;
  85 };
  86
  87 static inline struct repaper_epd *
  88 epd_from_tinydrm(struct tinydrm_device *tdev)
  89 {
  90         return container_of(tdev, struct repaper_epd, tinydrm);
  91 }
  92
  93 static int repaper_spi_transfer(struct spi_device *spi, u8 header,
  94                                 const void *tx, void *rx, size_t len)
  95 {
  96         void *txbuf = NULL, *rxbuf = NULL;
  97         struct spi_transfer tr[2] = {};
  98         u8 *headerbuf;
  99         int ret;
 100
 101         headerbuf = kmalloc(1, GFP_KERNEL);
 102         if (!headerbuf)
 103                 return -ENOMEM;
 104
 105         headerbuf[0] = header;
 106         tr[0].tx_buf = headerbuf;
 107         tr[0].len = 1;
 108
 109         /* Stack allocated tx? */
 110         if (tx && len <= 32) {
 111                 txbuf = kmemdup(tx, len, GFP_KERNEL);
 112                 if (!txbuf) {
 113                         ret = -ENOMEM;
 114                         goto out_free;
 115                 }
 116         }
 117
 118         if (rx) {
 119                 rxbuf = kmalloc(len, GFP_KERNEL);
 120                 if (!rxbuf) {
 121                         ret = -ENOMEM;
 122                         goto out_free;
 123                 }
 124         }
 125
 126         tr[1].tx_buf = txbuf ? txbuf : tx;
 127         tr[1].rx_buf = rxbuf;
 128         tr[1].len = len;
 129
 130         ndelay(80);
 131         ret = spi_sync_transfer(spi, tr, 2);
 132         if (rx && !ret)
 133                 memcpy(rx, rxbuf, len);
 134
 135 out_free:
 136         kfree(headerbuf);
 137         kfree(txbuf);
 138         kfree(rxbuf);
 139
 140         return ret;
 141 }
 142
 143 static int repaper_write_buf(struct spi_device *spi, u8 reg,
 144                              const u8 *buf, size_t len)
 145 {
 146         int ret;
 147
 148         ret = repaper_spi_transfer(spi, 0x70, &reg, NULL, 1);
 149         if (ret)
 150                 return ret;
 151
 152         return repaper_spi_transfer(spi, 0x72, buf, NULL, len);
 153 }
 154
 155 static int repaper_write_val(struct spi_device *spi, u8 reg, u8 val)
 156 {
 157         return repaper_write_buf(spi, reg, &val, 1);
 158 }
 159
 160 static int repaper_read_val(struct spi_device *spi, u8 reg)
 161 {
 162         int ret;
 163         u8 val;
 164
 165         ret = repaper_spi_transfer(spi, 0x70, &reg, NULL, 1);
 166         if (ret)
 167                 return ret;
 168
 169         ret = repaper_spi_transfer(spi, 0x73, NULL, &val, 1);
 170
 171         return ret ? ret : val;
 172 }
 173
 174 static int repaper_read_id(struct spi_device *spi)
 175 {
 176         int ret;
 177         u8 id;
 178
 179         ret = repaper_spi_transfer(spi, 0x71, NULL, &id, 1);
 180
 181         return ret ? ret : id;
 182 }
 183
 184 static void repaper_spi_mosi_low(struct spi_device *spi)
 185 {
 186         const u8 buf[1] = { 0 };
 187
 188         spi_write(spi, buf, 1);
 189 }
 190
 191 /* pixels on display are numbered from 1 so even is actually bits 1,3,5,... */
 192 static void repaper_even_pixels(struct repaper_epd *epd, u8 **pp,
 193                                 const u8 *data, u8 fixed_value, const u8 *mask,
 194                                 enum repaper_stage stage)
 195 {
 196         unsigned int b;
 197
 198         for (b = 0; b < (epd->width / 8); b++) {
 199                 if (data) {
 200                         u8 pixels = data[b] & 0xaa;
 201                         u8 pixel_mask = 0xff;
 202                         u8 p1, p2, p3, p4;
 203
 204                         if (mask) {
 205                                 pixel_mask = (mask[b] ^ pixels) & 0xaa;
 206                                 pixel_mask |= pixel_mask >> 1;
 207                         }
 208
 209                         switch (stage) {
 210                         case REPAPER_COMPENSATE: /* B -> W, W -> B (Current) */
 211                                 pixels = 0xaa | ((pixels ^ 0xaa) >> 1);
 212                                 break;
 213                         case REPAPER_WHITE:      /* B -> N, W -> W (Current) */
 214                                 pixels = 0x55 + ((pixels ^ 0xaa) >> 1);
 215                                 break;
 216                         case REPAPER_INVERSE:    /* B -> N, W -> B (New) */
 217                                 pixels = 0x55 | (pixels ^ 0xaa);
 218                                 break;
 219                         case REPAPER_NORMAL:     /* B -> B, W -> W (New) */
 220                                 pixels = 0xaa | (pixels >> 1);
 221                                 break;
 222                         }
 223
 224                         pixels = (pixels & pixel_mask) | (~pixel_mask & 0x55);
 225                         p1 = (pixels >> 6) & 0x03;
 226                         p2 = (pixels >> 4) & 0x03;
 227                         p3 = (pixels >> 2) & 0x03;
 228                         p4 = (pixels >> 0) & 0x03;
 229                         pixels = (p1 << 0) | (p2 << 2) | (p3 << 4) | (p4 << 6);
 230                         *(*pp)++ = pixels;
 231                 } else {
 232                         *(*pp)++ = fixed_value;
 233                 }
 234         }
 235 }
 236
 237 /* pixels on display are numbered from 1 so odd is actually bits 0,2,4,... */
 238 static void repaper_odd_pixels(struct repaper_epd *epd, u8 **pp,
 239                                const u8 *data, u8 fixed_value, const u8 *mask,
 240                                enum repaper_stage stage)
 241 {
 242         unsigned int b;
 243
 244         for (b = epd->width / 8; b > 0; b--) {
 245                 if (data) {
 246                         u8 pixels = data[b - 1] & 0x55;
 247                         u8 pixel_mask = 0xff;
 248
 249                         if (mask) {
 250                                 pixel_mask = (mask[b - 1] ^ pixels) & 0x55;
 251                                 pixel_mask |= pixel_mask << 1;
 252                         }
 253
 254                         switch (stage) {
 255                         case REPAPER_COMPENSATE: /* B -> W, W -> B (Current) */
 256                                 pixels = 0xaa | (pixels ^ 0x55);
 257                                 break;
 258                         case REPAPER_WHITE:      /* B -> N, W -> W (Current) */
 259                                 pixels = 0x55 + (pixels ^ 0x55);
 260                                 break;
 261                         case REPAPER_INVERSE:    /* B -> N, W -> B (New) */
 262                                 pixels = 0x55 | ((pixels ^ 0x55) << 1);
 263                                 break;
 264                         case REPAPER_NORMAL:     /* B -> B, W -> W (New) */
 265                                 pixels = 0xaa | pixels;
 266                                 break;
 267                         }
 268
 269                         pixels = (pixels & pixel_mask) | (~pixel_mask & 0x55);
 270                         *(*pp)++ = pixels;
 271                 } else {
 272                         *(*pp)++ = fixed_value;
 273                 }
 274         }
 275 }
 276
 277 /* interleave bits: (byte)76543210 -> (16 bit).7.6.5.4.3.2.1 */
 278 static inline u16 repaper_interleave_bits(u16 value)
 279 {
 280         value = (value | (value << 4)) & 0x0f0f;
 281         value = (value | (value << 2)) & 0x3333;
 282         value = (value | (value << 1)) & 0x5555;
 283
 284         return value;
 285 }
 286
 287 /* pixels on display are numbered from 1 */
 288 static void repaper_all_pixels(struct repaper_epd *epd, u8 **pp,
 289                                const u8 *data, u8 fixed_value, const u8 *mask,
 290                                enum repaper_stage stage)
 291 {
 292         unsigned int b;
 293
 294         for (b = epd->width / 8; b > 0; b--) {
 295                 if (data) {
 296                         u16 pixels = repaper_interleave_bits(data[b - 1]);
 297                         u16 pixel_mask = 0xffff;
 298
 299                         if (mask) {
 300                                 pixel_mask = repaper_interleave_bits(mask[b - 1]);
 301
 302                                 pixel_mask = (pixel_mask ^ pixels) & 0x5555;
 303                                 pixel_mask |= pixel_mask << 1;
 304                         }
 305
 306                         switch (stage) {
 307                         case REPAPER_COMPENSATE: /* B -> W, W -> B (Current) */
 308                                 pixels = 0xaaaa | (pixels ^ 0x5555);
 309                                 break;
 310                         case REPAPER_WHITE:      /* B -> N, W -> W (Current) */
 311                                 pixels = 0x5555 + (pixels ^ 0x5555);
 312                                 break;
 313                         case REPAPER_INVERSE:    /* B -> N, W -> B (New) */
 314                                 pixels = 0x5555 | ((pixels ^ 0x5555) << 1);
 315                                 break;
 316                         case REPAPER_NORMAL:     /* B -> B, W -> W (New) */
 317                                 pixels = 0xaaaa | pixels;
 318                                 break;
 319                         }
 320
 321                         pixels = (pixels & pixel_mask) | (~pixel_mask & 0x5555);
 322                         *(*pp)++ = pixels >> 8;
 323                         *(*pp)++ = pixels;
 324                 } else {
 325                         *(*pp)++ = fixed_value;
 326                         *(*pp)++ = fixed_value;
 327                 }
 328         }
 329 }
 330
 331 /* output one line of scan and data bytes to the display */
 332 static void repaper_one_line(struct repaper_epd *epd, unsigned int line,
 333                              const u8 *data, u8 fixed_value, const u8 *mask,
 334                              enum repaper_stage stage)
 335 {
 336         u8 *p = epd->line_buffer;
 337         unsigned int b;
 338
 339         repaper_spi_mosi_low(epd->spi);
 340
 341         if (epd->pre_border_byte)
 342                 *p++ = 0x00;
 343
 344         if (epd->middle_scan) {
 345                 /* data bytes */
 346                 repaper_odd_pixels(epd, &p, data, fixed_value, mask, stage);
 347
 348                 /* scan line */
 349                 for (b = epd->bytes_per_scan; b > 0; b--) {
 350                         if (line / 4 == b - 1)
 351                                 *p++ = 0x03 << (2 * (line & 0x03));
 352                         else
 353                                 *p++ = 0x00;
 354                 }
 355
 356                 /* data bytes */
 357                 repaper_even_pixels(epd, &p, data, fixed_value, mask, stage);
 358         } else {
 359                 /*
 360                  * even scan line, but as lines on display are numbered from 1,
 361                  * line: 1,3,5,...
 362                  */
 363                 for (b = 0; b < epd->bytes_per_scan; b++) {
 364                         if (0 != (line & 0x01) && line / 8 == b)
 365                                 *p++ = 0xc0 >> (line & 0x06);
 366                         else
 367                                 *p++ = 0x00;
 368                 }
 369
 370                 /* data bytes */
 371                 repaper_all_pixels(epd, &p, data, fixed_value, mask, stage);
 372
 373                 /*
 374                  * odd scan line, but as lines on display are numbered from 1,
 375                  * line: 0,2,4,6,...
 376                  */
 377                 for (b = epd->bytes_per_scan; b > 0; b--) {
 378                         if (0 == (line & 0x01) && line / 8 == b - 1)
 379                                 *p++ = 0x03 << (line & 0x06);
 380                         else
 381                                 *p++ = 0x00;
 382                 }
 383         }
 384
 385         switch (epd->border_byte) {
 386         case REPAPER_BORDER_BYTE_NONE:
 387                 break;
 388
 389         case REPAPER_BORDER_BYTE_ZERO:
 390                 *p++ = 0x00;
 391                 break;
 392
 393         case REPAPER_BORDER_BYTE_SET:
 394                 switch (stage) {
 395                 case REPAPER_COMPENSATE:
 396                 case REPAPER_WHITE:
 397                 case REPAPER_INVERSE:
 398                         *p++ = 0x00;
 399                         break;
 400                 case REPAPER_NORMAL:
 401                         *p++ = 0xaa;
 402                         break;
 403                 }
 404                 break;
 405         }
 406
 407         repaper_write_buf(epd->spi, 0x0a, epd->line_buffer,
 408                           p - epd->line_buffer);
 409
 410         /* Output data to panel */
 411         repaper_write_val(epd->spi, 0x02, 0x07);
 412
 413         repaper_spi_mosi_low(epd->spi);
 414 }
 415
 416 static void repaper_frame_fixed(struct repaper_epd *epd, u8 fixed_value,
 417                                 enum repaper_stage stage)
 418 {
 419         unsigned int line;
 420
 421         for (line = 0; line < epd->height; line++)
 422                 repaper_one_line(epd, line, NULL, fixed_value, NULL, stage);
 423 }
 424
 425 static void repaper_frame_data(struct repaper_epd *epd, const u8 *image,
 426                                const u8 *mask, enum repaper_stage stage)
 427 {
 428         unsigned int line;
 429
 430         if (!mask) {
 431                 for (line = 0; line < epd->height; line++) {
 432                         repaper_one_line(epd, line,
 433                                          &image[line * (epd->width / 8)],
 434                                          0, NULL, stage);
 435                 }
 436         } else {
 437                 for (line = 0; line < epd->height; line++) {
 438                         size_t n = line * epd->width / 8;
 439
 440                         repaper_one_line(epd, line, &image[n], 0, &mask[n],
 441                                          stage);
 442                 }
 443         }
 444 }
 445
 446 static void repaper_frame_fixed_repeat(struct repaper_epd *epd, u8 fixed_value,
 447                                        enum repaper_stage stage)
 448 {
 449         u64 start = local_clock();
 450         u64 end = start + (epd->factored_stage_time * 1000 * 1000);
 451
 452         do {
 453                 repaper_frame_fixed(epd, fixed_value, stage);
 454         } while (local_clock() < end);
 455 }
 456
 457 static void repaper_frame_data_repeat(struct repaper_epd *epd, const u8 *image,
 458                                       const u8 *mask, enum repaper_stage stage)
 459 {
 460         u64 start = local_clock();
 461         u64 end = start + (epd->factored_stage_time * 1000 * 1000);
 462
 463         do {
 464                 repaper_frame_data(epd, image, mask, stage);
 465         } while (local_clock() < end);
 466 }
 467
 468 static void repaper_get_temperature(struct repaper_epd *epd)
 469 {
 470         int ret, temperature = 0;
 471         unsigned int factor10x;
 472
 473         if (!epd->thermal)
 474                 return;
 475
 476         ret = thermal_zone_get_temp(epd->thermal, &temperature);
 477         if (ret) {
 478                 DRM_DEV_ERROR(&epd->spi->dev, "Failed to get temperature (%d)\n", ret);
 479                 return;
 480         }
 481
 482         temperature /= 1000;
 483
 484         if (temperature <= -10)
 485                 factor10x = 170;
 486         else if (temperature <= -5)
 487                 factor10x = 120;
 488         else if (temperature <= 5)
 489                 factor10x = 80;
 490         else if (temperature <= 10)
 491                 factor10x = 40;
 492         else if (temperature <= 15)
 493                 factor10x = 30;
 494         else if (temperature <= 20)
 495                 factor10x = 20;
 496         else if (temperature <= 40)
 497                 factor10x = 10;
 498         else
 499                 factor10x = 7;
 500
 501         epd->factored_stage_time = epd->stage_time * factor10x / 10;
 502 }
 503
 504 static void repaper_gray8_to_mono_reversed(u8 *buf, u32 width, u32 height)
 505 {
 506         u8 *gray8 = buf, *mono = buf;
 507         int y, xb, i;
 508
 509         for (y = 0; y < height; y++)
 510                 for (xb = 0; xb < width / 8; xb++) {
 511                         u8 byte = 0x00;
 512
 513                         for (i = 0; i < 8; i++) {
 514                                 int x = xb * 8 + i;
 515
 516                                 byte >>= 1;
 517                                 if (gray8[y * width + x] >> 7)
 518                                         byte |= BIT(7);
 519                         }
 520                         *mono++ = byte;
 521                 }
 522 }
 523
 524 static int repaper_fb_dirty(struct drm_framebuffer *fb,
 525                             struct drm_file *file_priv,
 526                             unsigned int flags, unsigned int color,
 527                             struct drm_clip_rect *clips,
 528                             unsigned int num_clips)
 529 {
 530         struct drm_gem_cma_object *cma_obj = drm_fb_cma_get_gem_obj(fb, 0);
 531         struct dma_buf_attachment *import_attach = cma_obj->base.import_attach;
 532         struct tinydrm_device *tdev = fb->dev->dev_private;
 533         struct repaper_epd *epd = epd_from_tinydrm(tdev);
 534         struct drm_clip_rect clip;
 535         u8 *buf = NULL;
 536         int ret = 0;
 537
 538         /* repaper can't do partial updates */
 539         clip.x1 = 0;
 540         clip.x2 = fb->width;
 541         clip.y1 = 0;
 542         clip.y2 = fb->height;
 543
 544         if (!epd->enabled)
 545                 return 0;
 546
 547         repaper_get_temperature(epd);
 548
 549         DRM_DEBUG("Flushing [FB:%d] st=%ums\n", fb->base.id,
 550                   epd->factored_stage_time);
 551
 552         buf = kmalloc_array(fb->width, fb->height, GFP_KERNEL);
 553         if (!buf)
 554                 return -ENOMEM;
 555
 556         if (import_attach) {
 557                 ret = dma_buf_begin_cpu_access(import_attach->dmabuf,
 558                                                DMA_FROM_DEVICE);
 559                 if (ret)
 560                         goto out_free;
 561         }
 562
 563         tinydrm_xrgb8888_to_gray8(buf, cma_obj->vaddr, fb, &clip);
 564
 565         if (import_attach) {
 566                 ret = dma_buf_end_cpu_access(import_attach->dmabuf,
 567                                              DMA_FROM_DEVICE);
 568                 if (ret)
 569                         goto out_free;
 570         }
 571
 572         repaper_gray8_to_mono_reversed(buf, fb->width, fb->height);
 573
 574         if (epd->partial) {
 575                 repaper_frame_data_repeat(epd, buf, epd->current_frame,
 576                                           REPAPER_NORMAL);
 577         } else if (epd->cleared) {
 578                 repaper_frame_data_repeat(epd, epd->current_frame, NULL,
 579                                           REPAPER_COMPENSATE);
 580                 repaper_frame_data_repeat(epd, epd->current_frame, NULL,
 581                                           REPAPER_WHITE);
 582                 repaper_frame_data_repeat(epd, buf, NULL, REPAPER_INVERSE);
 583                 repaper_frame_data_repeat(epd, buf, NULL, REPAPER_NORMAL);
 584
 585                 epd->partial = true;
 586         } else {
 587                 /* Clear display (anything -> white) */
 588                 repaper_frame_fixed_repeat(epd, 0xff, REPAPER_COMPENSATE);
 589                 repaper_frame_fixed_repeat(epd, 0xff, REPAPER_WHITE);
 590                 repaper_frame_fixed_repeat(epd, 0xaa, REPAPER_INVERSE);
 591                 repaper_frame_fixed_repeat(epd, 0xaa, REPAPER_NORMAL);
 592
 593                 /* Assuming a clear (white) screen output an image */
 594                 repaper_frame_fixed_repeat(epd, 0xaa, REPAPER_COMPENSATE);
 595                 repaper_frame_fixed_repeat(epd, 0xaa, REPAPER_WHITE);
 596                 repaper_frame_data_repeat(epd, buf, NULL, REPAPER_INVERSE);
 597                 repaper_frame_data_repeat(epd, buf, NULL, REPAPER_NORMAL);
 598
 599                 epd->cleared = true;
 600                 epd->partial = true;
 601         }
 602
 603         memcpy(epd->current_frame, buf, fb->width * fb->height / 8);
 604
 605         /*
 606          * An extra frame write is needed if pixels are set in the bottom line,
 607          * or else grey lines rises up from the pixels
 608          */
 609         if (epd->pre_border_byte) {
 610                 unsigned int x;
 611
 612                 for (x = 0; x < (fb->width / 8); x++)
 613                         if (buf[x + (fb->width * (fb->height - 1) / 8)]) {
 614                                 repaper_frame_data_repeat(epd, buf,
 615                                                           epd->current_frame,
 616                                                           REPAPER_NORMAL);
 617                                 break;
 618                         }
 619         }
 620
 621 out_free:
 622         kfree(buf);
 623
 624         return ret;
 625 }
 626
 627 static const struct drm_framebuffer_funcs repaper_fb_funcs = {
 628         .destroy        = drm_gem_fb_destroy,
 629         .create_handle  = drm_gem_fb_create_handle,
 630         .dirty          = tinydrm_fb_dirty,
 631 };
 632
 633 static void power_off(struct repaper_epd *epd)
 634 {
 635         /* Turn off power and all signals */
 636         gpiod_set_value_cansleep(epd->reset, 0);
 637         gpiod_set_value_cansleep(epd->panel_on, 0);
 638         if (epd->border)
 639                 gpiod_set_value_cansleep(epd->border, 0);
 640
 641         /* Ensure SPI MOSI and CLOCK are Low before CS Low */
 642         repaper_spi_mosi_low(epd->spi);
 643
 644         /* Discharge pulse */
 645         gpiod_set_value_cansleep(epd->discharge, 1);
 646         msleep(150);
 647         gpiod_set_value_cansleep(epd->discharge, 0);
 648 }
 649
 650 static void repaper_pipe_enable(struct drm_simple_display_pipe *pipe,
 651                                 struct drm_crtc_state *crtc_state,
 652                                 struct drm_plane_state *plane_state)
 653 {
 654         struct tinydrm_device *tdev = pipe_to_tinydrm(pipe);
 655         struct repaper_epd *epd = epd_from_tinydrm(tdev);
 656         struct spi_device *spi = epd->spi;
 657         struct device *dev = &spi->dev;
 658         bool dc_ok = false;
 659         int i, ret;
 660
 661         DRM_DEBUG_DRIVER("\n");
 662
 663         /* Power up sequence */
 664         gpiod_set_value_cansleep(epd->reset, 0);
 665         gpiod_set_value_cansleep(epd->panel_on, 0);
 666         gpiod_set_value_cansleep(epd->discharge, 0);
 667         if (epd->border)
 668                 gpiod_set_value_cansleep(epd->border, 0);
 669         repaper_spi_mosi_low(spi);
 670         usleep_range(5000, 10000);
 671
 672         gpiod_set_value_cansleep(epd->panel_on, 1);
 673         /*
 674          * This delay comes from the repaper.org userspace driver, it's not
 675          * mentioned in the datasheet.
 676          */
 677         usleep_range(10000, 15000);
 678         gpiod_set_value_cansleep(epd->reset, 1);
 679         if (epd->border)
 680                 gpiod_set_value_cansleep(epd->border, 1);
 681         usleep_range(5000, 10000);
 682         gpiod_set_value_cansleep(epd->reset, 0);
 683         usleep_range(5000, 10000);
 684         gpiod_set_value_cansleep(epd->reset, 1);
 685         usleep_range(5000, 10000);
 686
 687         /* Wait for COG to become ready */
 688         for (i = 100; i > 0; i--) {
 689                 if (!gpiod_get_value_cansleep(epd->busy))
 690                         break;
 691
 692                 usleep_range(10, 100);
 693         }
 694
 695         if (!i) {
 696                 DRM_DEV_ERROR(dev, "timeout waiting for panel to become ready.\n");
 697                 power_off(epd);
 698                 return;
 699         }
 700
 701         repaper_read_id(spi);
 702         ret = repaper_read_id(spi);
 703         if (ret != REPAPER_RID_G2_COG_ID) {
 704                 if (ret < 0)
 705                         dev_err(dev, "failed to read chip (%d)\n", ret);
 706                 else
 707                         dev_err(dev, "wrong COG ID 0x%02x\n", ret);
 708                 power_off(epd);
 709                 return;
 710         }
 711
 712         /* Disable OE */
 713         repaper_write_val(spi, 0x02, 0x40);
 714
 715         ret = repaper_read_val(spi, 0x0f);
 716         if (ret < 0 || !(ret & 0x80)) {
 717                 if (ret < 0)
 718                         DRM_DEV_ERROR(dev, "failed to read chip (%d)\n", ret);
 719                 else
 720                         DRM_DEV_ERROR(dev, "panel is reported broken\n");
 721                 power_off(epd);
 722                 return;
 723         }
 724
 725         /* Power saving mode */
 726         repaper_write_val(spi, 0x0b, 0x02);
 727         /* Channel select */
 728         repaper_write_buf(spi, 0x01, epd->channel_select, 8);
 729         /* High power mode osc */
 730         repaper_write_val(spi, 0x07, 0xd1);
 731         /* Power setting */
 732         repaper_write_val(spi, 0x08, 0x02);
 733         /* Vcom level */
 734         repaper_write_val(spi, 0x09, 0xc2);
 735         /* Power setting */
 736         repaper_write_val(spi, 0x04, 0x03);
 737         /* Driver latch on */
 738         repaper_write_val(spi, 0x03, 0x01);
 739         /* Driver latch off */
 740         repaper_write_val(spi, 0x03, 0x00);
 741         usleep_range(5000, 10000);
 742
 743         /* Start chargepump */
 744         for (i = 0; i < 4; ++i) {
 745                 /* Charge pump positive voltage on - VGH/VDL on */
 746                 repaper_write_val(spi, 0x05, 0x01);
 747                 msleep(240);
 748
 749                 /* Charge pump negative voltage on - VGL/VDL on */
 750                 repaper_write_val(spi, 0x05, 0x03);
 751                 msleep(40);
 752
 753                 /* Charge pump Vcom on - Vcom driver on */
 754                 repaper_write_val(spi, 0x05, 0x0f);
 755                 msleep(40);
 756
 757                 /* check DC/DC */
 758                 ret = repaper_read_val(spi, 0x0f);
 759                 if (ret < 0) {
 760                         DRM_DEV_ERROR(dev, "failed to read chip (%d)\n", ret);
 761                         power_off(epd);
 762                         return;
 763                 }
 764
 765                 if (ret & 0x40) {
 766                         dc_ok = true;
 767                         break;
 768                 }
 769         }
 770
 771         if (!dc_ok) {
 772                 DRM_DEV_ERROR(dev, "dc/dc failed\n");
 773                 power_off(epd);
 774                 return;
 775         }
 776
 777         /*
 778          * Output enable to disable
 779          * The userspace driver sets this to 0x04, but the datasheet says 0x06
 780          */
 781         repaper_write_val(spi, 0x02, 0x04);
 782
 783         epd->enabled = true;
 784         epd->partial = false;
 785 }
 786
 787 static void repaper_pipe_disable(struct drm_simple_display_pipe *pipe)
 788 {
 789         struct tinydrm_device *tdev = pipe_to_tinydrm(pipe);
 790         struct repaper_epd *epd = epd_from_tinydrm(tdev);
 791         struct spi_device *spi = epd->spi;
 792         unsigned int line;
 793
 794         DRM_DEBUG_DRIVER("\n");
 795
 796         mutex_lock(&tdev->dirty_lock);
 797         epd->enabled = false;
 798         mutex_unlock(&tdev->dirty_lock);
 799
 800         /* Nothing frame */
 801         for (line = 0; line < epd->height; line++)
 802                 repaper_one_line(epd, 0x7fffu, NULL, 0x00, NULL,
 803                                  REPAPER_COMPENSATE);
 804
 805         /* 2.7" */
 806         if (epd->border) {
 807                 /* Dummy line */
 808                 repaper_one_line(epd, 0x7fffu, NULL, 0x00, NULL,
 809                                  REPAPER_COMPENSATE);
 810                 msleep(25);
 811                 gpiod_set_value_cansleep(epd->border, 0);
 812                 msleep(200);
 813                 gpiod_set_value_cansleep(epd->border, 1);
 814         } else {
 815                 /* Border dummy line */
 816                 repaper_one_line(epd, 0x7fffu, NULL, 0x00, NULL,
 817                                  REPAPER_NORMAL);
 818                 msleep(200);
 819         }
 820
 821         /* not described in datasheet */
 822         repaper_write_val(spi, 0x0b, 0x00);
 823         /* Latch reset turn on */
 824         repaper_write_val(spi, 0x03, 0x01);
 825         /* Power off charge pump Vcom */
 826         repaper_write_val(spi, 0x05, 0x03);
 827         /* Power off charge pump neg voltage */
 828         repaper_write_val(spi, 0x05, 0x01);
 829         msleep(120);
 830         /* Discharge internal */
 831         repaper_write_val(spi, 0x04, 0x80);
 832         /* turn off all charge pumps */
 833         repaper_write_val(spi, 0x05, 0x00);
 834         /* Turn off osc */
 835         repaper_write_val(spi, 0x07, 0x01);
 836         msleep(50);
 837
 838         power_off(epd);
 839 }
 840
 841 static const struct drm_simple_display_pipe_funcs repaper_pipe_funcs = {
 842         .enable = repaper_pipe_enable,
 843         .disable = repaper_pipe_disable,
 844         .update = tinydrm_display_pipe_update,
 845         .prepare_fb = drm_gem_fb_simple_display_pipe_prepare_fb,
 846 };
 847
 848 static const uint32_t repaper_formats[] = {
 849         DRM_FORMAT_XRGB8888,
 850 };
 851
 852 static const struct drm_display_mode repaper_e1144cs021_mode = {
 853         TINYDRM_MODE(128, 96, 29, 22),
 854 };
 855
 856 static const u8 repaper_e1144cs021_cs[] = { 0x00, 0x00, 0x00, 0x00,
 857                                             0x00, 0x0f, 0xff, 0x00 };
 858
 859 static const struct drm_display_mode repaper_e1190cs021_mode = {
 860         TINYDRM_MODE(144, 128, 36, 32),
 861 };
 862
 863 static const u8 repaper_e1190cs021_cs[] = { 0x00, 0x00, 0x00, 0x03,
 864                                             0xfc, 0x00, 0x00, 0xff };
 865
 866 static const struct drm_display_mode repaper_e2200cs021_mode = {
 867         TINYDRM_MODE(200, 96, 46, 22),
 868 };
 869
 870 static const u8 repaper_e2200cs021_cs[] = { 0x00, 0x00, 0x00, 0x00,
 871                                             0x01, 0xff, 0xe0, 0x00 };
 872
 873 static const struct drm_display_mode repaper_e2271cs021_mode = {
 874         TINYDRM_MODE(264, 176, 57, 38),
 875 };
 876
 877 static const u8 repaper_e2271cs021_cs[] = { 0x00, 0x00, 0x00, 0x7f,
 878                                             0xff, 0xfe, 0x00, 0x00 };
 879
 880 DEFINE_DRM_GEM_CMA_FOPS(repaper_fops);
 881
 882 static struct drm_driver repaper_driver = {
 883         .driver_features        = DRIVER_GEM | DRIVER_MODESET | DRIVER_PRIME |
 884                                   DRIVER_ATOMIC,
 885         .fops                   = &repaper_fops,
 886         DRM_GEM_CMA_VMAP_DRIVER_OPS,
 887         .name                   = "repaper",
 888         .desc                   = "Pervasive Displays RePaper e-ink panels",
 889         .date                   = "20170405",
 890         .major                  = 1,
 891         .minor                  = 0,
 892 };
 893
 894 static const struct of_device_id repaper_of_match[] = {
 895         { .compatible = "pervasive,e1144cs021", .data = (void *)E1144CS021 },
 896         { .compatible = "pervasive,e1190cs021", .data = (void *)E1190CS021 },
 897         { .compatible = "pervasive,e2200cs021", .data = (void *)E2200CS021 },
 898         { .compatible = "pervasive,e2271cs021", .data = (void *)E2271CS021 },
 899         {},
 900 };
 901 MODULE_DEVICE_TABLE(of, repaper_of_match);
 902
 903 static const struct spi_device_id repaper_id[] = {
 904         { "e1144cs021", E1144CS021 },
 905         { "e1190cs021", E1190CS021 },
 906         { "e2200cs021", E2200CS021 },
 907         { "e2271cs021", E2271CS021 },
 908         { },
 909 };
 910 MODULE_DEVICE_TABLE(spi, repaper_id);
 911
 912 static int repaper_probe(struct spi_device *spi)
 913 {
 914         const struct drm_display_mode *mode;
 915         const struct spi_device_id *spi_id;
 916         const struct of_device_id *match;
 917         struct device *dev = &spi->dev;
 918         struct tinydrm_device *tdev;
 919         enum repaper_model model;
 920         const char *thermal_zone;
 921         struct repaper_epd *epd;
 922         size_t line_buffer_size;
 923         int ret;
 924
 925         match = of_match_device(repaper_of_match, dev);
 926         if (match) {
 927                 model = (enum repaper_model)match->data;
 928         } else {
 929                 spi_id = spi_get_device_id(spi);
 930                 model = spi_id->driver_data;
 931         }
 932
 933         /* The SPI device is used to allocate dma memory */
 934         if (!dev->coherent_dma_mask) {
 935                 ret = dma_coerce_mask_and_coherent(dev, DMA_BIT_MASK(32));
 936                 if (ret) {
 937                         dev_warn(dev, "Failed to set dma mask %d\n", ret);
 938                         return ret;
 939                 }
 940         }
 941
 942         epd = devm_kzalloc(dev, sizeof(*epd), GFP_KERNEL);
 943         if (!epd)
 944                 return -ENOMEM;
 945
 946         epd->spi = spi;
 947
 948         epd->panel_on = devm_gpiod_get(dev, "panel-on", GPIOD_OUT_LOW);
 949         if (IS_ERR(epd->panel_on)) {
 950                 ret = PTR_ERR(epd->panel_on);
 951                 if (ret != -EPROBE_DEFER)
 952                         DRM_DEV_ERROR(dev, "Failed to get gpio 'panel-on'\n");
 953                 return ret;
 954         }
 955
 956         epd->discharge = devm_gpiod_get(dev, "discharge", GPIOD_OUT_LOW);
 957         if (IS_ERR(epd->discharge)) {
 958                 ret = PTR_ERR(epd->discharge);
 959                 if (ret != -EPROBE_DEFER)
 960                         DRM_DEV_ERROR(dev, "Failed to get gpio 'discharge'\n");
 961                 return ret;
 962         }
 963
 964         epd->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
 965         if (IS_ERR(epd->reset)) {
 966                 ret = PTR_ERR(epd->reset);
 967                 if (ret != -EPROBE_DEFER)
 968                         DRM_DEV_ERROR(dev, "Failed to get gpio 'reset'\n");
 969                 return ret;
 970         }
 971
 972         epd->busy = devm_gpiod_get(dev, "busy", GPIOD_IN);
 973         if (IS_ERR(epd->busy)) {
 974                 ret = PTR_ERR(epd->busy);
 975                 if (ret != -EPROBE_DEFER)
 976                         DRM_DEV_ERROR(dev, "Failed to get gpio 'busy'\n");
 977                 return ret;
 978         }
 979
 980         if (!device_property_read_string(dev, "pervasive,thermal-zone",
 981                                          &thermal_zone)) {
 982                 epd->thermal = thermal_zone_get_zone_by_name(thermal_zone);
 983                 if (IS_ERR(epd->thermal)) {
 984                         DRM_DEV_ERROR(dev, "Failed to get thermal zone: %s\n", thermal_zone);
 985                         return PTR_ERR(epd->thermal);
 986                 }
 987         }
 988
 989         switch (model) {
 990         case E1144CS021:
 991                 mode = &repaper_e1144cs021_mode;
 992                 epd->channel_select = repaper_e1144cs021_cs;
 993                 epd->stage_time = 480;
 994                 epd->bytes_per_scan = 96 / 4;
 995                 epd->middle_scan = true; /* data-scan-data */
 996                 epd->pre_border_byte = false;
 997                 epd->border_byte = REPAPER_BORDER_BYTE_ZERO;
 998                 break;
 999
1000         case E1190CS021:
1001                 mode = &repaper_e1190cs021_mode;
1002                 epd->channel_select = repaper_e1190cs021_cs;
1003                 epd->stage_time = 480;
1004                 epd->bytes_per_scan = 128 / 4 / 2;
1005                 epd->middle_scan = false; /* scan-data-scan */
1006                 epd->pre_border_byte = false;
1007                 epd->border_byte = REPAPER_BORDER_BYTE_SET;
1008                 break;
1009
1010         case E2200CS021:
1011                 mode = &repaper_e2200cs021_mode;
1012                 epd->channel_select = repaper_e2200cs021_cs;
1013                 epd->stage_time = 480;
1014                 epd->bytes_per_scan = 96 / 4;
1015                 epd->middle_scan = true; /* data-scan-data */
1016                 epd->pre_border_byte = true;
1017                 epd->border_byte = REPAPER_BORDER_BYTE_NONE;
1018                 break;
1019
1020         case E2271CS021:
1021                 epd->border = devm_gpiod_get(dev, "border", GPIOD_OUT_LOW);
1022                 if (IS_ERR(epd->border)) {
1023                         ret = PTR_ERR(epd->border);
1024                         if (ret != -EPROBE_DEFER)
1025                                 DRM_DEV_ERROR(dev, "Failed to get gpio 'border'\n");
1026                         return ret;
1027                 }
1028
1029                 mode = &repaper_e2271cs021_mode;
1030                 epd->channel_select = repaper_e2271cs021_cs;
1031                 epd->stage_time = 630;
1032                 epd->bytes_per_scan = 176 / 4;
1033                 epd->middle_scan = true; /* data-scan-data */
1034                 epd->pre_border_byte = true;
1035                 epd->border_byte = REPAPER_BORDER_BYTE_NONE;
1036                 break;
1037
1038         default:
1039                 return -ENODEV;
1040         }
1041
1042         epd->width = mode->hdisplay;
1043         epd->height = mode->vdisplay;
1044         epd->factored_stage_time = epd->stage_time;
1045
1046         line_buffer_size = 2 * epd->width / 8 + epd->bytes_per_scan + 2;
1047         epd->line_buffer = devm_kzalloc(dev, line_buffer_size, GFP_KERNEL);
1048         if (!epd->line_buffer)
1049                 return -ENOMEM;
1050
1051         epd->current_frame = devm_kzalloc(dev, epd->width * epd->height / 8,
1052                                           GFP_KERNEL);
1053         if (!epd->current_frame)
1054                 return -ENOMEM;
1055
1056         tdev = &epd->tinydrm;
1057
1058         ret = devm_tinydrm_init(dev, tdev, &repaper_fb_funcs, &repaper_driver);
1059         if (ret)
1060                 return ret;
1061
1062         tdev->fb_dirty = repaper_fb_dirty;
1063
1064         ret = tinydrm_display_pipe_init(tdev, &repaper_pipe_funcs,
1065                                         DRM_MODE_CONNECTOR_VIRTUAL,
1066                                         repaper_formats,
1067                                         ARRAY_SIZE(repaper_formats), mode, 0);
1068         if (ret)
1069                 return ret;
1070
1071         drm_mode_config_reset(tdev->drm);
1072         spi_set_drvdata(spi, tdev);
1073
1074         DRM_DEBUG_DRIVER("SPI speed: %uMHz\n", spi->max_speed_hz / 1000000);
1075
1076         return devm_tinydrm_register(tdev);
1077 }
1078
1079 static void repaper_shutdown(struct spi_device *spi)
1080 {
1081         struct tinydrm_device *tdev = spi_get_drvdata(spi);
1082
1083         tinydrm_shutdown(tdev);
1084 }
1085
1086 static struct spi_driver repaper_spi_driver = {
1087         .driver = {
1088                 .name = "repaper",
1089                 .owner = THIS_MODULE,
1090                 .of_match_table = repaper_of_match,
1091         },
1092         .id_table = repaper_id,
1093         .probe = repaper_probe,
1094         .shutdown = repaper_shutdown,
1095 };
1096 module_spi_driver(repaper_spi_driver);
1097
1098 MODULE_DESCRIPTION("Pervasive Displays RePaper DRM driver");
1099 MODULE_AUTHOR("Noralf Trønnes");
1100 MODULE_LICENSE("GPL");