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/tinydrm/tinydrm.h>
  30 #include <drm/tinydrm/tinydrm-helpers.h>
  31
  32 #define REPAPER_RID_G2_COG_ID   0x12
  33
  34 enum repaper_model {
  35         E1144CS021 = 1,
  36         E1190CS021,
  37         E2200CS021,
  38         E2271CS021,
  39 };
  40
  41 enum repaper_stage {         /* Image pixel -> Display pixel */
  42         REPAPER_COMPENSATE,  /* B -> W, W -> B (Current Image) */
  43         REPAPER_WHITE,       /* B -> N, W -> W (Current Image) */
  44         REPAPER_INVERSE,     /* B -> N, W -> B (New Image) */
  45         REPAPER_NORMAL       /* B -> B, W -> W (New Image) */
  46 };
  47
  48 enum repaper_epd_border_byte {
  49         REPAPER_BORDER_BYTE_NONE,
  50         REPAPER_BORDER_BYTE_ZERO,
  51         REPAPER_BORDER_BYTE_SET,
  52 };
  53
  54 struct repaper_epd {
  55         struct tinydrm_device tinydrm;
  56         struct spi_device *spi;
  57
  58         struct gpio_desc *panel_on;
  59         struct gpio_desc *border;
  60         struct gpio_desc *discharge;
  61         struct gpio_desc *reset;
  62         struct gpio_desc *busy;
  63
  64         struct thermal_zone_device *thermal;
  65
  66         unsigned int height;
  67         unsigned int width;
  68         unsigned int bytes_per_scan;
  69         const u8 *channel_select;
  70         unsigned int stage_time;
  71         unsigned int factored_stage_time;
  72         bool middle_scan;
  73         bool pre_border_byte;
  74         enum repaper_epd_border_byte border_byte;
  75
  76         u8 *line_buffer;
  77         void *current_frame;
  78
  79         bool enabled;
  80         bool cleared;
  81         bool partial;
  82 };
  83
  84 static inline struct repaper_epd *
  85 epd_from_tinydrm(struct tinydrm_device *tdev)
  86 {
  87         return container_of(tdev, struct repaper_epd, tinydrm);
  88 }
  89
  90 static int repaper_spi_transfer(struct spi_device *spi, u8 header,
  91                                 const void *tx, void *rx, size_t len)
  92 {
  93         void *txbuf = NULL, *rxbuf = NULL;
  94         struct spi_transfer tr[2] = {};
  95         u8 *headerbuf;
  96         int ret;
  97
  98         headerbuf = kmalloc(1, GFP_KERNEL);
  99         if (!headerbuf)
 100                 return -ENOMEM;
 101
 102         headerbuf[0] = header;
 103         tr[0].tx_buf = headerbuf;
 104         tr[0].len = 1;
 105
 106         /* Stack allocated tx? */
 107         if (tx && len <= 32) {
 108                 txbuf = kmalloc(len, GFP_KERNEL);
 109                 if (!txbuf) {
 110                         ret = -ENOMEM;
 111                         goto out_free;
 112                 }
 113                 memcpy(txbuf, tx, len);
 114         }
 115
 116         if (rx) {
 117                 rxbuf = kmalloc(len, GFP_KERNEL);
 118                 if (!rxbuf) {
 119                         ret = -ENOMEM;
 120                         goto out_free;
 121                 }
 122         }
 123
 124         tr[1].tx_buf = txbuf ? txbuf : tx;
 125         tr[1].rx_buf = rxbuf;
 126         tr[1].len = len;
 127
 128         ndelay(80);
 129         ret = spi_sync_transfer(spi, tr, 2);
 130         if (rx && !ret)
 131                 memcpy(rx, rxbuf, len);
 132
 133 out_free:
 134         kfree(headerbuf);
 135         kfree(txbuf);
 136         kfree(rxbuf);
 137
 138         return ret;
 139 }
 140
 141 static int repaper_write_buf(struct spi_device *spi, u8 reg,
 142                              const u8 *buf, size_t len)
 143 {
 144         int ret;
 145
 146         ret = repaper_spi_transfer(spi, 0x70, &reg, NULL, 1);
 147         if (ret)
 148                 return ret;
 149
 150         return repaper_spi_transfer(spi, 0x72, buf, NULL, len);
 151 }
 152
 153 static int repaper_write_val(struct spi_device *spi, u8 reg, u8 val)
 154 {
 155         return repaper_write_buf(spi, reg, &val, 1);
 156 }
 157
 158 static int repaper_read_val(struct spi_device *spi, u8 reg)
 159 {
 160         int ret;
 161         u8 val;
 162
 163         ret = repaper_spi_transfer(spi, 0x70, &reg, NULL, 1);
 164         if (ret)
 165                 return ret;
 166
 167         ret = repaper_spi_transfer(spi, 0x73, NULL, &val, 1);
 168
 169         return ret ? ret : val;
 170 }
 171
 172 static int repaper_read_id(struct spi_device *spi)
 173 {
 174         int ret;
 175         u8 id;
 176
 177         ret = repaper_spi_transfer(spi, 0x71, NULL, &id, 1);
 178
 179         return ret ? ret : id;
 180 }
 181
 182 static void repaper_spi_mosi_low(struct spi_device *spi)
 183 {
 184         const u8 buf[1] = { 0 };
 185
 186         spi_write(spi, buf, 1);
 187 }
 188
 189 /* pixels on display are numbered from 1 so even is actually bits 1,3,5,... */
 190 static void repaper_even_pixels(struct repaper_epd *epd, u8 **pp,
 191                                 const u8 *data, u8 fixed_value, const u8 *mask,
 192                                 enum repaper_stage stage)
 193 {
 194         unsigned int b;
 195
 196         for (b = 0; b < (epd->width / 8); b++) {
 197                 if (data) {
 198                         u8 pixels = data[b] & 0xaa;
 199                         u8 pixel_mask = 0xff;
 200                         u8 p1, p2, p3, p4;
 201
 202                         if (mask) {
 203                                 pixel_mask = (mask[b] ^ pixels) & 0xaa;
 204                                 pixel_mask |= pixel_mask >> 1;
 205                         }
 206
 207                         switch (stage) {
 208                         case REPAPER_COMPENSATE: /* B -> W, W -> B (Current) */
 209                                 pixels = 0xaa | ((pixels ^ 0xaa) >> 1);
 210                                 break;
 211                         case REPAPER_WHITE:      /* B -> N, W -> W (Current) */
 212                                 pixels = 0x55 + ((pixels ^ 0xaa) >> 1);
 213                                 break;
 214                         case REPAPER_INVERSE:    /* B -> N, W -> B (New) */
 215                                 pixels = 0x55 | (pixels ^ 0xaa);
 216                                 break;
 217                         case REPAPER_NORMAL:     /* B -> B, W -> W (New) */
 218                                 pixels = 0xaa | (pixels >> 1);
 219                                 break;
 220                         }
 221
 222                         pixels = (pixels & pixel_mask) | (~pixel_mask & 0x55);
 223                         p1 = (pixels >> 6) & 0x03;
 224                         p2 = (pixels >> 4) & 0x03;
 225                         p3 = (pixels >> 2) & 0x03;
 226                         p4 = (pixels >> 0) & 0x03;
 227                         pixels = (p1 << 0) | (p2 << 2) | (p3 << 4) | (p4 << 6);
 228                         *(*pp)++ = pixels;
 229                 } else {
 230                         *(*pp)++ = fixed_value;
 231                 }
 232         }
 233 }
 234
 235 /* pixels on display are numbered from 1 so odd is actually bits 0,2,4,... */
 236 static void repaper_odd_pixels(struct repaper_epd *epd, u8 **pp,
 237                                const u8 *data, u8 fixed_value, const u8 *mask,
 238                                enum repaper_stage stage)
 239 {
 240         unsigned int b;
 241
 242         for (b = epd->width / 8; b > 0; b--) {
 243                 if (data) {
 244                         u8 pixels = data[b - 1] & 0x55;
 245                         u8 pixel_mask = 0xff;
 246
 247                         if (mask) {
 248                                 pixel_mask = (mask[b - 1] ^ pixels) & 0x55;
 249                                 pixel_mask |= pixel_mask << 1;
 250                         }
 251
 252                         switch (stage) {
 253                         case REPAPER_COMPENSATE: /* B -> W, W -> B (Current) */
 254                                 pixels = 0xaa | (pixels ^ 0x55);
 255                                 break;
 256                         case REPAPER_WHITE:      /* B -> N, W -> W (Current) */
 257                                 pixels = 0x55 + (pixels ^ 0x55);
 258                                 break;
 259                         case REPAPER_INVERSE:    /* B -> N, W -> B (New) */
 260                                 pixels = 0x55 | ((pixels ^ 0x55) << 1);
 261                                 break;
 262                         case REPAPER_NORMAL:     /* B -> B, W -> W (New) */
 263                                 pixels = 0xaa | pixels;
 264                                 break;
 265                         }
 266
 267                         pixels = (pixels & pixel_mask) | (~pixel_mask & 0x55);
 268                         *(*pp)++ = pixels;
 269                 } else {
 270                         *(*pp)++ = fixed_value;
 271                 }
 272         }
 273 }
 274
 275 /* interleave bits: (byte)76543210 -> (16 bit).7.6.5.4.3.2.1 */
 276 static inline u16 repaper_interleave_bits(u16 value)
 277 {
 278         value = (value | (value << 4)) & 0x0f0f;
 279         value = (value | (value << 2)) & 0x3333;
 280         value = (value | (value << 1)) & 0x5555;
 281
 282         return value;
 283 }
 284
 285 /* pixels on display are numbered from 1 */
 286 static void repaper_all_pixels(struct repaper_epd *epd, u8 **pp,
 287                                const u8 *data, u8 fixed_value, const u8 *mask,
 288                                enum repaper_stage stage)
 289 {
 290         unsigned int b;
 291
 292         for (b = epd->width / 8; b > 0; b--) {
 293                 if (data) {
 294                         u16 pixels = repaper_interleave_bits(data[b - 1]);
 295                         u16 pixel_mask = 0xffff;
 296
 297                         if (mask) {
 298                                 pixel_mask = repaper_interleave_bits(mask[b - 1]);
 299
 300                                 pixel_mask = (pixel_mask ^ pixels) & 0x5555;
 301                                 pixel_mask |= pixel_mask << 1;
 302                         }
 303
 304                         switch (stage) {
 305                         case REPAPER_COMPENSATE: /* B -> W, W -> B (Current) */
 306                                 pixels = 0xaaaa | (pixels ^ 0x5555);
 307                                 break;
 308                         case REPAPER_WHITE:      /* B -> N, W -> W (Current) */
 309                                 pixels = 0x5555 + (pixels ^ 0x5555);
 310                                 break;
 311                         case REPAPER_INVERSE:    /* B -> N, W -> B (New) */
 312                                 pixels = 0x5555 | ((pixels ^ 0x5555) << 1);
 313                                 break;
 314                         case REPAPER_NORMAL:     /* B -> B, W -> W (New) */
 315                                 pixels = 0xaaaa | pixels;
 316                                 break;
 317                         }
 318
 319                         pixels = (pixels & pixel_mask) | (~pixel_mask & 0x5555);
 320                         *(*pp)++ = pixels >> 8;
 321                         *(*pp)++ = pixels;
 322                 } else {
 323                         *(*pp)++ = fixed_value;
 324                         *(*pp)++ = fixed_value;
 325                 }
 326         }
 327 }
 328
 329 /* output one line of scan and data bytes to the display */
 330 static void repaper_one_line(struct repaper_epd *epd, unsigned int line,
 331                              const u8 *data, u8 fixed_value, const u8 *mask,
 332                              enum repaper_stage stage)
 333 {
 334         u8 *p = epd->line_buffer;
 335         unsigned int b;
 336
 337         repaper_spi_mosi_low(epd->spi);
 338
 339         if (epd->pre_border_byte)
 340                 *p++ = 0x00;
 341
 342         if (epd->middle_scan) {
 343                 /* data bytes */
 344                 repaper_odd_pixels(epd, &p, data, fixed_value, mask, stage);
 345
 346                 /* scan line */
 347                 for (b = epd->bytes_per_scan; b > 0; b--) {
 348                         if (line / 4 == b - 1)
 349                                 *p++ = 0x03 << (2 * (line & 0x03));
 350                         else
 351                                 *p++ = 0x00;
 352                 }
 353
 354                 /* data bytes */
 355                 repaper_even_pixels(epd, &p, data, fixed_value, mask, stage);
 356         } else {
 357                 /*
 358                  * even scan line, but as lines on display are numbered from 1,
 359                  * line: 1,3,5,...
 360                  */
 361                 for (b = 0; b < epd->bytes_per_scan; b++) {
 362                         if (0 != (line & 0x01) && line / 8 == b)
 363                                 *p++ = 0xc0 >> (line & 0x06);
 364                         else
 365                                 *p++ = 0x00;
 366                 }
 367
 368                 /* data bytes */
 369                 repaper_all_pixels(epd, &p, data, fixed_value, mask, stage);
 370
 371                 /*
 372                  * odd scan line, but as lines on display are numbered from 1,
 373                  * line: 0,2,4,6,...
 374                  */
 375                 for (b = epd->bytes_per_scan; b > 0; b--) {
 376                         if (0 == (line & 0x01) && line / 8 == b - 1)
 377                                 *p++ = 0x03 << (line & 0x06);
 378                         else
 379                                 *p++ = 0x00;
 380                 }
 381         }
 382
 383         switch (epd->border_byte) {
 384         case REPAPER_BORDER_BYTE_NONE:
 385                 break;
 386
 387         case REPAPER_BORDER_BYTE_ZERO:
 388                 *p++ = 0x00;
 389                 break;
 390
 391         case REPAPER_BORDER_BYTE_SET:
 392                 switch (stage) {
 393                 case REPAPER_COMPENSATE:
 394                 case REPAPER_WHITE:
 395                 case REPAPER_INVERSE:
 396                         *p++ = 0x00;
 397                         break;
 398                 case REPAPER_NORMAL:
 399                         *p++ = 0xaa;
 400                         break;
 401                 }
 402                 break;
 403         }
 404
 405         repaper_write_buf(epd->spi, 0x0a, epd->line_buffer,
 406                           p - epd->line_buffer);
 407
 408         /* Output data to panel */
 409         repaper_write_val(epd->spi, 0x02, 0x07);
 410
 411         repaper_spi_mosi_low(epd->spi);
 412 }
 413
 414 static void repaper_frame_fixed(struct repaper_epd *epd, u8 fixed_value,
 415                                 enum repaper_stage stage)
 416 {
 417         unsigned int line;
 418
 419         for (line = 0; line < epd->height; line++)
 420                 repaper_one_line(epd, line, NULL, fixed_value, NULL, stage);
 421 }
 422
 423 static void repaper_frame_data(struct repaper_epd *epd, const u8 *image,
 424                                const u8 *mask, enum repaper_stage stage)
 425 {
 426         unsigned int line;
 427
 428         if (!mask) {
 429                 for (line = 0; line < epd->height; line++) {
 430                         repaper_one_line(epd, line,
 431                                          &image[line * (epd->width / 8)],
 432                                          0, NULL, stage);
 433                 }
 434         } else {
 435                 for (line = 0; line < epd->height; line++) {
 436                         size_t n = line * epd->width / 8;
 437
 438                         repaper_one_line(epd, line, &image[n], 0, &mask[n],
 439                                          stage);
 440                 }
 441         }
 442 }
 443
 444 static void repaper_frame_fixed_repeat(struct repaper_epd *epd, u8 fixed_value,
 445                                        enum repaper_stage stage)
 446 {
 447         u64 start = local_clock();
 448         u64 end = start + (epd->factored_stage_time * 1000 * 1000);
 449
 450         do {
 451                 repaper_frame_fixed(epd, fixed_value, stage);
 452         } while (local_clock() < end);
 453 }
 454
 455 static void repaper_frame_data_repeat(struct repaper_epd *epd, const u8 *image,
 456                                       const u8 *mask, enum repaper_stage stage)
 457 {
 458         u64 start = local_clock();
 459         u64 end = start + (epd->factored_stage_time * 1000 * 1000);
 460
 461         do {
 462                 repaper_frame_data(epd, image, mask, stage);
 463         } while (local_clock() < end);
 464 }
 465
 466 static void repaper_get_temperature(struct repaper_epd *epd)
 467 {
 468         int ret, temperature = 0;
 469         unsigned int factor10x;
 470
 471         if (!epd->thermal)
 472                 return;
 473
 474         ret = thermal_zone_get_temp(epd->thermal, &temperature);
 475         if (ret) {
 476                 dev_err(&epd->spi->dev, "Failed to get temperature (%d)\n",
 477                         ret);
 478                 return;
 479         }
 480
 481         temperature /= 1000;
 482
 483         if (temperature <= -10)
 484                 factor10x = 170;
 485         else if (temperature <= -5)
 486                 factor10x = 120;
 487         else if (temperature <= 5)
 488                 factor10x = 80;
 489         else if (temperature <= 10)
 490                 factor10x = 40;
 491         else if (temperature <= 15)
 492                 factor10x = 30;
 493         else if (temperature <= 20)
 494                 factor10x = 20;
 495         else if (temperature <= 40)
 496                 factor10x = 10;
 497         else
 498                 factor10x = 7;
 499
 500         epd->factored_stage_time = epd->stage_time * factor10x / 10;
 501 }
 502
 503 static void repaper_gray8_to_mono_reversed(u8 *buf, u32 width, u32 height)
 504 {
 505         u8 *gray8 = buf, *mono = buf;
 506         int y, xb, i;
 507
 508         for (y = 0; y < height; y++)
 509                 for (xb = 0; xb < width / 8; xb++) {
 510                         u8 byte = 0x00;
 511
 512                         for (i = 0; i < 8; i++) {
 513                                 int x = xb * 8 + i;
 514
 515                                 byte >>= 1;
 516                                 if (gray8[y * width + x] >> 7)
 517                                         byte |= BIT(7);
 518                         }
 519                         *mono++ = byte;
 520                 }
 521 }
 522
 523 static int repaper_fb_dirty(struct drm_framebuffer *fb,
 524                             struct drm_file *file_priv,
 525                             unsigned int flags, unsigned int color,
 526                             struct drm_clip_rect *clips,
 527                             unsigned int num_clips)
 528 {
 529         struct drm_gem_cma_object *cma_obj = drm_fb_cma_get_gem_obj(fb, 0);
 530         struct dma_buf_attachment *import_attach = cma_obj->base.import_attach;
 531         struct tinydrm_device *tdev = fb->dev->dev_private;
 532         struct repaper_epd *epd = epd_from_tinydrm(tdev);
 533         struct drm_clip_rect clip;
 534         u8 *buf = NULL;
 535         int ret = 0;
 536
 537         /* repaper can't do partial updates */
 538         clip.x1 = 0;
 539         clip.x2 = fb->width;
 540         clip.y1 = 0;
 541         clip.y2 = fb->height;
 542
 543         mutex_lock(&tdev->dirty_lock);
 544
 545         if (!epd->enabled)
 546                 goto out_unlock;
 547
 548         /* fbdev can flush even when we're not interested */
 549         if (tdev->pipe.plane.fb != fb)
 550                 goto out_unlock;
 551
 552         repaper_get_temperature(epd);
 553
 554         DRM_DEBUG("Flushing [FB:%d] st=%ums\n", fb->base.id,
 555                   epd->factored_stage_time);
 556
 557         buf = kmalloc(fb->width * fb->height, GFP_KERNEL);
 558         if (!buf) {
 559                 ret = -ENOMEM;
 560                 goto out_unlock;
 561         }
 562
 563         if (import_attach) {
 564                 ret = dma_buf_begin_cpu_access(import_attach->dmabuf,
 565                                                DMA_FROM_DEVICE);
 566                 if (ret)
 567                         goto out_unlock;
 568         }
 569
 570         tinydrm_xrgb8888_to_gray8(buf, cma_obj->vaddr, fb, &clip);
 571
 572         if (import_attach) {
 573                 ret = dma_buf_end_cpu_access(import_attach->dmabuf,
 574                                              DMA_FROM_DEVICE);
 575                 if (ret)
 576                         goto out_unlock;
 577         }
 578
 579         repaper_gray8_to_mono_reversed(buf, fb->width, fb->height);
 580
 581         if (epd->partial) {
 582                 repaper_frame_data_repeat(epd, buf, epd->current_frame,
 583                                           REPAPER_NORMAL);
 584         } else if (epd->cleared) {
 585                 repaper_frame_data_repeat(epd, epd->current_frame, NULL,
 586                                           REPAPER_COMPENSATE);
 587                 repaper_frame_data_repeat(epd, epd->current_frame, NULL,
 588                                           REPAPER_WHITE);
 589                 repaper_frame_data_repeat(epd, buf, NULL, REPAPER_INVERSE);
 590                 repaper_frame_data_repeat(epd, buf, NULL, REPAPER_NORMAL);
 591
 592                 epd->partial = true;
 593         } else {
 594                 /* Clear display (anything -> white) */
 595                 repaper_frame_fixed_repeat(epd, 0xff, REPAPER_COMPENSATE);
 596                 repaper_frame_fixed_repeat(epd, 0xff, REPAPER_WHITE);
 597                 repaper_frame_fixed_repeat(epd, 0xaa, REPAPER_INVERSE);
 598                 repaper_frame_fixed_repeat(epd, 0xaa, REPAPER_NORMAL);
 599
 600                 /* Assuming a clear (white) screen output an image */
 601                 repaper_frame_fixed_repeat(epd, 0xaa, REPAPER_COMPENSATE);
 602                 repaper_frame_fixed_repeat(epd, 0xaa, REPAPER_WHITE);
 603                 repaper_frame_data_repeat(epd, buf, NULL, REPAPER_INVERSE);
 604                 repaper_frame_data_repeat(epd, buf, NULL, REPAPER_NORMAL);
 605
 606                 epd->cleared = true;
 607                 epd->partial = true;
 608         }
 609
 610         memcpy(epd->current_frame, buf, fb->width * fb->height / 8);
 611
 612         /*
 613          * An extra frame write is needed if pixels are set in the bottom line,
 614          * or else grey lines rises up from the pixels
 615          */
 616         if (epd->pre_border_byte) {
 617                 unsigned int x;
 618
 619                 for (x = 0; x < (fb->width / 8); x++)
 620                         if (buf[x + (fb->width * (fb->height - 1) / 8)]) {
 621                                 repaper_frame_data_repeat(epd, buf,
 622                                                           epd->current_frame,
 623                                                           REPAPER_NORMAL);
 624                                 break;
 625                         }
 626         }
 627
 628 out_unlock:
 629         mutex_unlock(&tdev->dirty_lock);
 630
 631         if (ret)
 632                 dev_err(fb->dev->dev, "Failed to update display (%d)\n", ret);
 633         kfree(buf);
 634
 635         return ret;
 636 }
 637
 638 static const struct drm_framebuffer_funcs repaper_fb_funcs = {
 639         .destroy        = drm_fb_cma_destroy,
 640         .create_handle  = drm_fb_cma_create_handle,
 641         .dirty          = repaper_fb_dirty,
 642 };
 643
 644 static void power_off(struct repaper_epd *epd)
 645 {
 646         /* Turn off power and all signals */
 647         gpiod_set_value_cansleep(epd->reset, 0);
 648         gpiod_set_value_cansleep(epd->panel_on, 0);
 649         if (epd->border)
 650                 gpiod_set_value_cansleep(epd->border, 0);
 651
 652         /* Ensure SPI MOSI and CLOCK are Low before CS Low */
 653         repaper_spi_mosi_low(epd->spi);
 654
 655         /* Discharge pulse */
 656         gpiod_set_value_cansleep(epd->discharge, 1);
 657         msleep(150);
 658         gpiod_set_value_cansleep(epd->discharge, 0);
 659 }
 660
 661 static void repaper_pipe_enable(struct drm_simple_display_pipe *pipe,
 662                                 struct drm_crtc_state *crtc_state)
 663 {
 664         struct tinydrm_device *tdev = pipe_to_tinydrm(pipe);
 665         struct repaper_epd *epd = epd_from_tinydrm(tdev);
 666         struct spi_device *spi = epd->spi;
 667         struct device *dev = &spi->dev;
 668         bool dc_ok = false;
 669         int i, ret;
 670
 671         DRM_DEBUG_DRIVER("\n");
 672
 673         /* Power up sequence */
 674         gpiod_set_value_cansleep(epd->reset, 0);
 675         gpiod_set_value_cansleep(epd->panel_on, 0);
 676         gpiod_set_value_cansleep(epd->discharge, 0);
 677         if (epd->border)
 678                 gpiod_set_value_cansleep(epd->border, 0);
 679         repaper_spi_mosi_low(spi);
 680         usleep_range(5000, 10000);
 681
 682         gpiod_set_value_cansleep(epd->panel_on, 1);
 683         /*
 684          * This delay comes from the repaper.org userspace driver, it's not
 685          * mentioned in the datasheet.
 686          */
 687         usleep_range(10000, 15000);
 688         gpiod_set_value_cansleep(epd->reset, 1);
 689         if (epd->border)
 690                 gpiod_set_value_cansleep(epd->border, 1);
 691         usleep_range(5000, 10000);
 692         gpiod_set_value_cansleep(epd->reset, 0);
 693         usleep_range(5000, 10000);
 694         gpiod_set_value_cansleep(epd->reset, 1);
 695         usleep_range(5000, 10000);
 696
 697         /* Wait for COG to become ready */
 698         for (i = 100; i > 0; i--) {
 699                 if (!gpiod_get_value_cansleep(epd->busy))
 700                         break;
 701
 702                 usleep_range(10, 100);
 703         }
 704
 705         if (!i) {
 706                 dev_err(dev, "timeout waiting for panel to become ready.\n");
 707                 power_off(epd);
 708                 return;
 709         }
 710
 711         repaper_read_id(spi);
 712         ret = repaper_read_id(spi);
 713         if (ret != REPAPER_RID_G2_COG_ID) {
 714                 if (ret < 0)
 715                         dev_err(dev, "failed to read chip (%d)\n", ret);
 716                 else
 717                         dev_err(dev, "wrong COG ID 0x%02x\n", ret);
 718                 power_off(epd);
 719                 return;
 720         }
 721
 722         /* Disable OE */
 723         repaper_write_val(spi, 0x02, 0x40);
 724
 725         ret = repaper_read_val(spi, 0x0f);
 726         if (ret < 0 || !(ret & 0x80)) {
 727                 if (ret < 0)
 728                         dev_err(dev, "failed to read chip (%d)\n", ret);
 729                 else
 730                         dev_err(dev, "panel is reported broken\n");
 731                 power_off(epd);
 732                 return;
 733         }
 734
 735         /* Power saving mode */
 736         repaper_write_val(spi, 0x0b, 0x02);
 737         /* Channel select */
 738         repaper_write_buf(spi, 0x01, epd->channel_select, 8);
 739         /* High power mode osc */
 740         repaper_write_val(spi, 0x07, 0xd1);
 741         /* Power setting */
 742         repaper_write_val(spi, 0x08, 0x02);
 743         /* Vcom level */
 744         repaper_write_val(spi, 0x09, 0xc2);
 745         /* Power setting */
 746         repaper_write_val(spi, 0x04, 0x03);
 747         /* Driver latch on */
 748         repaper_write_val(spi, 0x03, 0x01);
 749         /* Driver latch off */
 750         repaper_write_val(spi, 0x03, 0x00);
 751         usleep_range(5000, 10000);
 752
 753         /* Start chargepump */
 754         for (i = 0; i < 4; ++i) {
 755                 /* Charge pump positive voltage on - VGH/VDL on */
 756                 repaper_write_val(spi, 0x05, 0x01);
 757                 msleep(240);
 758
 759                 /* Charge pump negative voltage on - VGL/VDL on */
 760                 repaper_write_val(spi, 0x05, 0x03);
 761                 msleep(40);
 762
 763                 /* Charge pump Vcom on - Vcom driver on */
 764                 repaper_write_val(spi, 0x05, 0x0f);
 765                 msleep(40);
 766
 767                 /* check DC/DC */
 768                 ret = repaper_read_val(spi, 0x0f);
 769                 if (ret < 0) {
 770                         dev_err(dev, "failed to read chip (%d)\n", ret);
 771                         power_off(epd);
 772                         return;
 773                 }
 774
 775                 if (ret & 0x40) {
 776                         dc_ok = true;
 777                         break;
 778                 }
 779         }
 780
 781         if (!dc_ok) {
 782                 dev_err(dev, "dc/dc failed\n");
 783                 power_off(epd);
 784                 return;
 785         }
 786
 787         /*
 788          * Output enable to disable
 789          * The userspace driver sets this to 0x04, but the datasheet says 0x06
 790          */
 791         repaper_write_val(spi, 0x02, 0x04);
 792
 793         epd->enabled = true;
 794         epd->partial = false;
 795 }
 796
 797 static void repaper_pipe_disable(struct drm_simple_display_pipe *pipe)
 798 {
 799         struct tinydrm_device *tdev = pipe_to_tinydrm(pipe);
 800         struct repaper_epd *epd = epd_from_tinydrm(tdev);
 801         struct spi_device *spi = epd->spi;
 802         unsigned int line;
 803
 804         DRM_DEBUG_DRIVER("\n");
 805
 806         mutex_lock(&tdev->dirty_lock);
 807         epd->enabled = false;
 808         mutex_unlock(&tdev->dirty_lock);
 809
 810         /* Nothing frame */
 811         for (line = 0; line < epd->height; line++)
 812                 repaper_one_line(epd, 0x7fffu, NULL, 0x00, NULL,
 813                                  REPAPER_COMPENSATE);
 814
 815         /* 2.7" */
 816         if (epd->border) {
 817                 /* Dummy line */
 818                 repaper_one_line(epd, 0x7fffu, NULL, 0x00, NULL,
 819                                  REPAPER_COMPENSATE);
 820                 msleep(25);
 821                 gpiod_set_value_cansleep(epd->border, 0);
 822                 msleep(200);
 823                 gpiod_set_value_cansleep(epd->border, 1);
 824         } else {
 825                 /* Border dummy line */
 826                 repaper_one_line(epd, 0x7fffu, NULL, 0x00, NULL,
 827                                  REPAPER_NORMAL);
 828                 msleep(200);
 829         }
 830
 831         /* not described in datasheet */
 832         repaper_write_val(spi, 0x0b, 0x00);
 833         /* Latch reset turn on */
 834         repaper_write_val(spi, 0x03, 0x01);
 835         /* Power off charge pump Vcom */
 836         repaper_write_val(spi, 0x05, 0x03);
 837         /* Power off charge pump neg voltage */
 838         repaper_write_val(spi, 0x05, 0x01);
 839         msleep(120);
 840         /* Discharge internal */
 841         repaper_write_val(spi, 0x04, 0x80);
 842         /* turn off all charge pumps */
 843         repaper_write_val(spi, 0x05, 0x00);
 844         /* Turn off osc */
 845         repaper_write_val(spi, 0x07, 0x01);
 846         msleep(50);
 847
 848         power_off(epd);
 849 }
 850
 851 static const struct drm_simple_display_pipe_funcs repaper_pipe_funcs = {
 852         .enable = repaper_pipe_enable,
 853         .disable = repaper_pipe_disable,
 854         .update = tinydrm_display_pipe_update,
 855         .prepare_fb = tinydrm_display_pipe_prepare_fb,
 856 };
 857
 858 static const uint32_t repaper_formats[] = {
 859         DRM_FORMAT_XRGB8888,
 860 };
 861
 862 static const struct drm_display_mode repaper_e1144cs021_mode = {
 863         TINYDRM_MODE(128, 96, 29, 22),
 864 };
 865
 866 static const u8 repaper_e1144cs021_cs[] = { 0x00, 0x00, 0x00, 0x00,
 867                                             0x00, 0x0f, 0xff, 0x00 };
 868
 869 static const struct drm_display_mode repaper_e1190cs021_mode = {
 870         TINYDRM_MODE(144, 128, 36, 32),
 871 };
 872
 873 static const u8 repaper_e1190cs021_cs[] = { 0x00, 0x00, 0x00, 0x03,
 874                                             0xfc, 0x00, 0x00, 0xff };
 875
 876 static const struct drm_display_mode repaper_e2200cs021_mode = {
 877         TINYDRM_MODE(200, 96, 46, 22),
 878 };
 879
 880 static const u8 repaper_e2200cs021_cs[] = { 0x00, 0x00, 0x00, 0x00,
 881                                             0x01, 0xff, 0xe0, 0x00 };
 882
 883 static const struct drm_display_mode repaper_e2271cs021_mode = {
 884         TINYDRM_MODE(264, 176, 57, 38),
 885 };
 886
 887 static const u8 repaper_e2271cs021_cs[] = { 0x00, 0x00, 0x00, 0x7f,
 888                                             0xff, 0xfe, 0x00, 0x00 };
 889
 890 DEFINE_DRM_GEM_CMA_FOPS(repaper_fops);
 891
 892 static struct drm_driver repaper_driver = {
 893         .driver_features        = DRIVER_GEM | DRIVER_MODESET | DRIVER_PRIME |
 894                                   DRIVER_ATOMIC,
 895         .fops                   = &repaper_fops,
 896         TINYDRM_GEM_DRIVER_OPS,
 897         .name                   = "repaper",
 898         .desc                   = "Pervasive Displays RePaper e-ink panels",
 899         .date                   = "20170405",
 900         .major                  = 1,
 901         .minor                  = 0,
 902 };
 903
 904 static const struct of_device_id repaper_of_match[] = {
 905         { .compatible = "pervasive,e1144cs021", .data = (void *)E1144CS021 },
 906         { .compatible = "pervasive,e1190cs021", .data = (void *)E1190CS021 },
 907         { .compatible = "pervasive,e2200cs021", .data = (void *)E2200CS021 },
 908         { .compatible = "pervasive,e2271cs021", .data = (void *)E2271CS021 },
 909         {},
 910 };
 911 MODULE_DEVICE_TABLE(of, repaper_of_match);
 912
 913 static const struct spi_device_id repaper_id[] = {
 914         { "e1144cs021", E1144CS021 },
 915         { "e1190cs021", E1190CS021 },
 916         { "e2200cs021", E2200CS021 },
 917         { "e2271cs021", E2271CS021 },
 918         { },
 919 };
 920 MODULE_DEVICE_TABLE(spi, repaper_id);
 921
 922 static int repaper_probe(struct spi_device *spi)
 923 {
 924         const struct drm_display_mode *mode;
 925         const struct spi_device_id *spi_id;
 926         const struct of_device_id *match;
 927         struct device *dev = &spi->dev;
 928         struct tinydrm_device *tdev;
 929         enum repaper_model model;
 930         const char *thermal_zone;
 931         struct repaper_epd *epd;
 932         size_t line_buffer_size;
 933         int ret;
 934
 935         match = of_match_device(repaper_of_match, dev);
 936         if (match) {
 937                 model = (enum repaper_model)match->data;
 938         } else {
 939                 spi_id = spi_get_device_id(spi);
 940                 model = spi_id->driver_data;
 941         }
 942
 943         /* The SPI device is used to allocate dma memory */
 944         if (!dev->coherent_dma_mask) {
 945                 ret = dma_coerce_mask_and_coherent(dev, DMA_BIT_MASK(32));
 946                 if (ret) {
 947                         dev_warn(dev, "Failed to set dma mask %d\n", ret);
 948                         return ret;
 949                 }
 950         }
 951
 952         epd = devm_kzalloc(dev, sizeof(*epd), GFP_KERNEL);
 953         if (!epd)
 954                 return -ENOMEM;
 955
 956         epd->spi = spi;
 957
 958         epd->panel_on = devm_gpiod_get(dev, "panel-on", GPIOD_OUT_LOW);
 959         if (IS_ERR(epd->panel_on)) {
 960                 ret = PTR_ERR(epd->panel_on);
 961                 if (ret != -EPROBE_DEFER)
 962                         dev_err(dev, "Failed to get gpio 'panel-on'\n");
 963                 return ret;
 964         }
 965
 966         epd->discharge = devm_gpiod_get(dev, "discharge", GPIOD_OUT_LOW);
 967         if (IS_ERR(epd->discharge)) {
 968                 ret = PTR_ERR(epd->discharge);
 969                 if (ret != -EPROBE_DEFER)
 970                         dev_err(dev, "Failed to get gpio 'discharge'\n");
 971                 return ret;
 972         }
 973
 974         epd->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
 975         if (IS_ERR(epd->reset)) {
 976                 ret = PTR_ERR(epd->reset);
 977                 if (ret != -EPROBE_DEFER)
 978                         dev_err(dev, "Failed to get gpio 'reset'\n");
 979                 return ret;
 980         }
 981
 982         epd->busy = devm_gpiod_get(dev, "busy", GPIOD_IN);
 983         if (IS_ERR(epd->busy)) {
 984                 ret = PTR_ERR(epd->busy);
 985                 if (ret != -EPROBE_DEFER)
 986                         dev_err(dev, "Failed to get gpio 'busy'\n");
 987                 return ret;
 988         }
 989
 990         if (!device_property_read_string(dev, "pervasive,thermal-zone",
 991                                          &thermal_zone)) {
 992                 epd->thermal = thermal_zone_get_zone_by_name(thermal_zone);
 993                 if (IS_ERR(epd->thermal)) {
 994                         dev_err(dev, "Failed to get thermal zone: %s\n",
 995                                 thermal_zone);
 996                         return PTR_ERR(epd->thermal);
 997                 }
 998         }
 999
1000         switch (model) {
1001         case E1144CS021:
1002                 mode = &repaper_e1144cs021_mode;
1003                 epd->channel_select = repaper_e1144cs021_cs;
1004                 epd->stage_time = 480;
1005                 epd->bytes_per_scan = 96 / 4;
1006                 epd->middle_scan = true; /* data-scan-data */
1007                 epd->pre_border_byte = false;
1008                 epd->border_byte = REPAPER_BORDER_BYTE_ZERO;
1009                 break;
1010
1011         case E1190CS021:
1012                 mode = &repaper_e1190cs021_mode;
1013                 epd->channel_select = repaper_e1190cs021_cs;
1014                 epd->stage_time = 480;
1015                 epd->bytes_per_scan = 128 / 4 / 2;
1016                 epd->middle_scan = false; /* scan-data-scan */
1017                 epd->pre_border_byte = false;
1018                 epd->border_byte = REPAPER_BORDER_BYTE_SET;
1019                 break;
1020
1021         case E2200CS021:
1022                 mode = &repaper_e2200cs021_mode;
1023                 epd->channel_select = repaper_e2200cs021_cs;
1024                 epd->stage_time = 480;
1025                 epd->bytes_per_scan = 96 / 4;
1026                 epd->middle_scan = true; /* data-scan-data */
1027                 epd->pre_border_byte = true;
1028                 epd->border_byte = REPAPER_BORDER_BYTE_NONE;
1029                 break;
1030
1031         case E2271CS021:
1032                 epd->border = devm_gpiod_get(dev, "border", GPIOD_OUT_LOW);
1033                 if (IS_ERR(epd->border)) {
1034                         ret = PTR_ERR(epd->border);
1035                         if (ret != -EPROBE_DEFER)
1036                                 dev_err(dev, "Failed to get gpio 'border'\n");
1037                         return ret;
1038                 }
1039
1040                 mode = &repaper_e2271cs021_mode;
1041                 epd->channel_select = repaper_e2271cs021_cs;
1042                 epd->stage_time = 630;
1043                 epd->bytes_per_scan = 176 / 4;
1044                 epd->middle_scan = true; /* data-scan-data */
1045                 epd->pre_border_byte = true;
1046                 epd->border_byte = REPAPER_BORDER_BYTE_NONE;
1047                 break;
1048
1049         default:
1050                 return -ENODEV;
1051         }
1052
1053         epd->width = mode->hdisplay;
1054         epd->height = mode->vdisplay;
1055         epd->factored_stage_time = epd->stage_time;
1056
1057         line_buffer_size = 2 * epd->width / 8 + epd->bytes_per_scan + 2;
1058         epd->line_buffer = devm_kzalloc(dev, line_buffer_size, GFP_KERNEL);
1059         if (!epd->line_buffer)
1060                 return -ENOMEM;
1061
1062         epd->current_frame = devm_kzalloc(dev, epd->width * epd->height / 8,
1063                                           GFP_KERNEL);
1064         if (!epd->current_frame)
1065                 return -ENOMEM;
1066
1067         tdev = &epd->tinydrm;
1068
1069         ret = devm_tinydrm_init(dev, tdev, &repaper_fb_funcs, &repaper_driver);
1070         if (ret)
1071                 return ret;
1072
1073         ret = tinydrm_display_pipe_init(tdev, &repaper_pipe_funcs,
1074                                         DRM_MODE_CONNECTOR_VIRTUAL,
1075                                         repaper_formats,
1076                                         ARRAY_SIZE(repaper_formats), mode, 0);
1077         if (ret)
1078                 return ret;
1079
1080         drm_mode_config_reset(tdev->drm);
1081
1082         ret = devm_tinydrm_register(tdev);
1083         if (ret)
1084                 return ret;
1085
1086         spi_set_drvdata(spi, tdev);
1087
1088         DRM_DEBUG_DRIVER("Initialized %s:%s @%uMHz on minor %d\n",
1089                          tdev->drm->driver->name, dev_name(dev),
1090                          spi->max_speed_hz / 1000000,
1091                          tdev->drm->primary->index);
1092
1093         return 0;
1094 }
1095
1096 static void repaper_shutdown(struct spi_device *spi)
1097 {
1098         struct tinydrm_device *tdev = spi_get_drvdata(spi);
1099
1100         tinydrm_shutdown(tdev);
1101 }
1102
1103 static struct spi_driver repaper_spi_driver = {
1104         .driver = {
1105                 .name = "repaper",
1106                 .owner = THIS_MODULE,
1107                 .of_match_table = repaper_of_match,
1108         },
1109         .id_table = repaper_id,
1110         .probe = repaper_probe,
1111         .shutdown = repaper_shutdown,
1112 };
1113 module_spi_driver(repaper_spi_driver);
1114
1115 MODULE_DESCRIPTION("Pervasive Displays RePaper DRM driver");
1116 MODULE_AUTHOR("Noralf Trønnes");
1117 MODULE_LICENSE("GPL");