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