drivers/gpu/drm/tinydrm/repaper.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * DRM driver for Pervasive Displays RePaper branded e-ink panels
   4  *
   5  * Copyright 2013-2017 Pervasive Displays, Inc.
   6  * Copyright 2017 Noralf Trønnes
   7  *
   8  * The driver supports:
   9  * Material Film: Aurora Mb (V231)
  10  * Driver IC: G2 (eTC)
  11  *
  12  * The controller code was taken from the userspace driver:
  13  * https://github.com/repaper/gratis
  14  */
  15
  16 #include <linux/delay.h>
  17 #include <linux/dma-buf.h>
  18 #include <linux/gpio/consumer.h>
  19 #include <linux/module.h>
  20 #include <linux/of_device.h>
  21 #include <linux/sched/clock.h>
  22 #include <linux/spi/spi.h>
  23 #include <linux/thermal.h>
  24
  25 #include <drm/drm_atomic_helper.h>
  26 #include <drm/drm_damage_helper.h>
  27 #include <drm/drm_drv.h>
  28 #include <drm/drm_fb_cma_helper.h>
  29 #include <drm/drm_fb_helper.h>
  30 #include <drm/drm_format_helper.h>
  31 #include <drm/drm_gem_cma_helper.h>
  32 #include <drm/drm_gem_framebuffer_helper.h>
  33 #include <drm/drm_rect.h>
  34 #include <drm/drm_vblank.h>
  35 #include <drm/drm_simple_kms_helper.h>
  36 #include <drm/tinydrm/tinydrm-helpers.h>
  37
  38 #define REPAPER_RID_G2_COG_ID   0x12
  39
  40 enum repaper_model {
  41         E1144CS021 = 1,
  42         E1190CS021,
  43         E2200CS021,
  44         E2271CS021,
  45 };
  46
  47 enum repaper_stage {         /* Image pixel -> Display pixel */
  48         REPAPER_COMPENSATE,  /* B -> W, W -> B (Current Image) */
  49         REPAPER_WHITE,       /* B -> N, W -> W (Current Image) */
  50         REPAPER_INVERSE,     /* B -> N, W -> B (New Image) */
  51         REPAPER_NORMAL       /* B -> B, W -> W (New Image) */
  52 };
  53
  54 enum repaper_epd_border_byte {
  55         REPAPER_BORDER_BYTE_NONE,
  56         REPAPER_BORDER_BYTE_ZERO,
  57         REPAPER_BORDER_BYTE_SET,
  58 };
  59
  60 struct repaper_epd {
  61         struct drm_device drm;
  62         struct drm_simple_display_pipe pipe;
  63         struct spi_device *spi;
  64
  65         struct gpio_desc *panel_on;
  66         struct gpio_desc *border;
  67         struct gpio_desc *discharge;
  68         struct gpio_desc *reset;
  69         struct gpio_desc *busy;
  70
  71         struct thermal_zone_device *thermal;
  72
  73         unsigned int height;
  74         unsigned int width;
  75         unsigned int bytes_per_scan;
  76         const u8 *channel_select;
  77         unsigned int stage_time;
  78         unsigned int factored_stage_time;
  79         bool middle_scan;
  80         bool pre_border_byte;
  81         enum repaper_epd_border_byte border_byte;
  82
  83         u8 *line_buffer;
  84         void *current_frame;
  85
  86         bool enabled;
  87         bool cleared;
  88         bool partial;
  89 };
  90
  91 static inline struct repaper_epd *drm_to_epd(struct drm_device *drm)
  92 {
  93         return container_of(drm, struct repaper_epd, drm);
  94 }
  95
  96 static int repaper_spi_transfer(struct spi_device *spi, u8 header,
  97                                 const void *tx, void *rx, size_t len)
  98 {
  99         void *txbuf = NULL, *rxbuf = NULL;
 100         struct spi_transfer tr[2] = {};
 101         u8 *headerbuf;
 102         int ret;
 103
 104         headerbuf = kmalloc(1, GFP_KERNEL);
 105         if (!headerbuf)
 106                 return -ENOMEM;
 107
 108         headerbuf[0] = header;
 109         tr[0].tx_buf = headerbuf;
 110         tr[0].len = 1;
 111
 112         /* Stack allocated tx? */
 113         if (tx && len <= 32) {
 114                 txbuf = kmemdup(tx, len, GFP_KERNEL);
 115                 if (!txbuf) {
 116                         ret = -ENOMEM;
 117                         goto out_free;
 118                 }
 119         }
 120
 121         if (rx) {
 122                 rxbuf = kmalloc(len, GFP_KERNEL);
 123                 if (!rxbuf) {
 124                         ret = -ENOMEM;
 125                         goto out_free;
 126                 }
 127         }
 128
 129         tr[1].tx_buf = txbuf ? txbuf : tx;
 130         tr[1].rx_buf = rxbuf;
 131         tr[1].len = len;
 132
 133         ndelay(80);
 134         ret = spi_sync_transfer(spi, tr, 2);
 135         if (rx && !ret)
 136                 memcpy(rx, rxbuf, len);
 137
 138 out_free:
 139         kfree(headerbuf);
 140         kfree(txbuf);
 141         kfree(rxbuf);
 142
 143         return ret;
 144 }
 145
 146 static int repaper_write_buf(struct spi_device *spi, u8 reg,
 147                              const u8 *buf, size_t len)
 148 {
 149         int ret;
 150
 151         ret = repaper_spi_transfer(spi, 0x70, &reg, NULL, 1);
 152         if (ret)
 153                 return ret;
 154
 155         return repaper_spi_transfer(spi, 0x72, buf, NULL, len);
 156 }
 157
 158 static int repaper_write_val(struct spi_device *spi, u8 reg, u8 val)
 159 {
 160         return repaper_write_buf(spi, reg, &val, 1);
 161 }
 162
 163 static int repaper_read_val(struct spi_device *spi, u8 reg)
 164 {
 165         int ret;
 166         u8 val;
 167
 168         ret = repaper_spi_transfer(spi, 0x70, &reg, NULL, 1);
 169         if (ret)
 170                 return ret;
 171
 172         ret = repaper_spi_transfer(spi, 0x73, NULL, &val, 1);
 173
 174         return ret ? ret : val;
 175 }
 176
 177 static int repaper_read_id(struct spi_device *spi)
 178 {
 179         int ret;
 180         u8 id;
 181
 182         ret = repaper_spi_transfer(spi, 0x71, NULL, &id, 1);
 183
 184         return ret ? ret : id;
 185 }
 186
 187 static void repaper_spi_mosi_low(struct spi_device *spi)
 188 {
 189         const u8 buf[1] = { 0 };
 190
 191         spi_write(spi, buf, 1);
 192 }
 193
 194 /* pixels on display are numbered from 1 so even is actually bits 1,3,5,... */
 195 static void repaper_even_pixels(struct repaper_epd *epd, u8 **pp,
 196                                 const u8 *data, u8 fixed_value, const u8 *mask,
 197                                 enum repaper_stage stage)
 198 {
 199         unsigned int b;
 200
 201         for (b = 0; b < (epd->width / 8); b++) {
 202                 if (data) {
 203                         u8 pixels = data[b] & 0xaa;
 204                         u8 pixel_mask = 0xff;
 205                         u8 p1, p2, p3, p4;
 206
 207                         if (mask) {
 208                                 pixel_mask = (mask[b] ^ pixels) & 0xaa;
 209                                 pixel_mask |= pixel_mask >> 1;
 210                         }
 211
 212                         switch (stage) {
 213                         case REPAPER_COMPENSATE: /* B -> W, W -> B (Current) */
 214                                 pixels = 0xaa | ((pixels ^ 0xaa) >> 1);
 215                                 break;
 216                         case REPAPER_WHITE:      /* B -> N, W -> W (Current) */
 217                                 pixels = 0x55 + ((pixels ^ 0xaa) >> 1);
 218                                 break;
 219                         case REPAPER_INVERSE:    /* B -> N, W -> B (New) */
 220                                 pixels = 0x55 | (pixels ^ 0xaa);
 221                                 break;
 222                         case REPAPER_NORMAL:     /* B -> B, W -> W (New) */
 223                                 pixels = 0xaa | (pixels >> 1);
 224                                 break;
 225                         }
 226
 227                         pixels = (pixels & pixel_mask) | (~pixel_mask & 0x55);
 228                         p1 = (pixels >> 6) & 0x03;
 229                         p2 = (pixels >> 4) & 0x03;
 230                         p3 = (pixels >> 2) & 0x03;
 231                         p4 = (pixels >> 0) & 0x03;
 232                         pixels = (p1 << 0) | (p2 << 2) | (p3 << 4) | (p4 << 6);
 233                         *(*pp)++ = pixels;
 234                 } else {
 235                         *(*pp)++ = fixed_value;
 236                 }
 237         }
 238 }
 239
 240 /* pixels on display are numbered from 1 so odd is actually bits 0,2,4,... */
 241 static void repaper_odd_pixels(struct repaper_epd *epd, u8 **pp,
 242                                const u8 *data, u8 fixed_value, const u8 *mask,
 243                                enum repaper_stage stage)
 244 {
 245         unsigned int b;
 246
 247         for (b = epd->width / 8; b > 0; b--) {
 248                 if (data) {
 249                         u8 pixels = data[b - 1] & 0x55;
 250                         u8 pixel_mask = 0xff;
 251
 252                         if (mask) {
 253                                 pixel_mask = (mask[b - 1] ^ pixels) & 0x55;
 254                                 pixel_mask |= pixel_mask << 1;
 255                         }
 256
 257                         switch (stage) {
 258                         case REPAPER_COMPENSATE: /* B -> W, W -> B (Current) */
 259                                 pixels = 0xaa | (pixels ^ 0x55);
 260                                 break;
 261                         case REPAPER_WHITE:      /* B -> N, W -> W (Current) */
 262                                 pixels = 0x55 + (pixels ^ 0x55);
 263                                 break;
 264                         case REPAPER_INVERSE:    /* B -> N, W -> B (New) */
 265                                 pixels = 0x55 | ((pixels ^ 0x55) << 1);
 266                                 break;
 267                         case REPAPER_NORMAL:     /* B -> B, W -> W (New) */
 268                                 pixels = 0xaa | pixels;
 269                                 break;
 270                         }
 271
 272                         pixels = (pixels & pixel_mask) | (~pixel_mask & 0x55);
 273                         *(*pp)++ = pixels;
 274                 } else {
 275                         *(*pp)++ = fixed_value;
 276                 }
 277         }
 278 }
 279
 280 /* interleave bits: (byte)76543210 -> (16 bit).7.6.5.4.3.2.1 */
 281 static inline u16 repaper_interleave_bits(u16 value)
 282 {
 283         value = (value | (value << 4)) & 0x0f0f;
 284         value = (value | (value << 2)) & 0x3333;
 285         value = (value | (value << 1)) & 0x5555;
 286
 287         return value;
 288 }
 289
 290 /* pixels on display are numbered from 1 */
 291 static void repaper_all_pixels(struct repaper_epd *epd, u8 **pp,
 292                                const u8 *data, u8 fixed_value, const u8 *mask,
 293                                enum repaper_stage stage)
 294 {
 295         unsigned int b;
 296
 297         for (b = epd->width / 8; b > 0; b--) {
 298                 if (data) {
 299                         u16 pixels = repaper_interleave_bits(data[b - 1]);
 300                         u16 pixel_mask = 0xffff;
 301
 302                         if (mask) {
 303                                 pixel_mask = repaper_interleave_bits(mask[b - 1]);
 304
 305                                 pixel_mask = (pixel_mask ^ pixels) & 0x5555;
 306                                 pixel_mask |= pixel_mask << 1;
 307                         }
 308
 309                         switch (stage) {
 310                         case REPAPER_COMPENSATE: /* B -> W, W -> B (Current) */
 311                                 pixels = 0xaaaa | (pixels ^ 0x5555);
 312                                 break;
 313                         case REPAPER_WHITE:      /* B -> N, W -> W (Current) */
 314                                 pixels = 0x5555 + (pixels ^ 0x5555);
 315                                 break;
 316                         case REPAPER_INVERSE:    /* B -> N, W -> B (New) */
 317                                 pixels = 0x5555 | ((pixels ^ 0x5555) << 1);
 318                                 break;
 319                         case REPAPER_NORMAL:     /* B -> B, W -> W (New) */
 320                                 pixels = 0xaaaa | pixels;
 321                                 break;
 322                         }
 323
 324                         pixels = (pixels & pixel_mask) | (~pixel_mask & 0x5555);
 325                         *(*pp)++ = pixels >> 8;
 326                         *(*pp)++ = pixels;
 327                 } else {
 328                         *(*pp)++ = fixed_value;
 329                         *(*pp)++ = fixed_value;
 330                 }
 331         }
 332 }
 333
 334 /* output one line of scan and data bytes to the display */
 335 static void repaper_one_line(struct repaper_epd *epd, unsigned int line,
 336                              const u8 *data, u8 fixed_value, const u8 *mask,
 337                              enum repaper_stage stage)
 338 {
 339         u8 *p = epd->line_buffer;
 340         unsigned int b;
 341
 342         repaper_spi_mosi_low(epd->spi);
 343
 344         if (epd->pre_border_byte)
 345                 *p++ = 0x00;
 346
 347         if (epd->middle_scan) {
 348                 /* data bytes */
 349                 repaper_odd_pixels(epd, &p, data, fixed_value, mask, stage);
 350
 351                 /* scan line */
 352                 for (b = epd->bytes_per_scan; b > 0; b--) {
 353                         if (line / 4 == b - 1)
 354                                 *p++ = 0x03 << (2 * (line & 0x03));
 355                         else
 356                                 *p++ = 0x00;
 357                 }
 358
 359                 /* data bytes */
 360                 repaper_even_pixels(epd, &p, data, fixed_value, mask, stage);
 361         } else {
 362                 /*
 363                  * even scan line, but as lines on display are numbered from 1,
 364                  * line: 1,3,5,...
 365                  */
 366                 for (b = 0; b < epd->bytes_per_scan; b++) {
 367                         if (0 != (line & 0x01) && line / 8 == b)
 368                                 *p++ = 0xc0 >> (line & 0x06);
 369                         else
 370                                 *p++ = 0x00;
 371                 }
 372
 373                 /* data bytes */
 374                 repaper_all_pixels(epd, &p, data, fixed_value, mask, stage);
 375
 376                 /*
 377                  * odd scan line, but as lines on display are numbered from 1,
 378                  * line: 0,2,4,6,...
 379                  */
 380                 for (b = epd->bytes_per_scan; b > 0; b--) {
 381                         if (0 == (line & 0x01) && line / 8 == b - 1)
 382                                 *p++ = 0x03 << (line & 0x06);
 383                         else
 384                                 *p++ = 0x00;
 385                 }
 386         }
 387
 388         switch (epd->border_byte) {
 389         case REPAPER_BORDER_BYTE_NONE:
 390                 break;
 391
 392         case REPAPER_BORDER_BYTE_ZERO:
 393                 *p++ = 0x00;
 394                 break;
 395
 396         case REPAPER_BORDER_BYTE_SET:
 397                 switch (stage) {
 398                 case REPAPER_COMPENSATE:
 399                 case REPAPER_WHITE:
 400                 case REPAPER_INVERSE:
 401                         *p++ = 0x00;
 402                         break;
 403                 case REPAPER_NORMAL:
 404                         *p++ = 0xaa;
 405                         break;
 406                 }
 407                 break;
 408         }
 409
 410         repaper_write_buf(epd->spi, 0x0a, epd->line_buffer,
 411                           p - epd->line_buffer);
 412
 413         /* Output data to panel */
 414         repaper_write_val(epd->spi, 0x02, 0x07);
 415
 416         repaper_spi_mosi_low(epd->spi);
 417 }
 418
 419 static void repaper_frame_fixed(struct repaper_epd *epd, u8 fixed_value,
 420                                 enum repaper_stage stage)
 421 {
 422         unsigned int line;
 423
 424         for (line = 0; line < epd->height; line++)
 425                 repaper_one_line(epd, line, NULL, fixed_value, NULL, stage);
 426 }
 427
 428 static void repaper_frame_data(struct repaper_epd *epd, const u8 *image,
 429                                const u8 *mask, enum repaper_stage stage)
 430 {
 431         unsigned int line;
 432
 433         if (!mask) {
 434                 for (line = 0; line < epd->height; line++) {
 435                         repaper_one_line(epd, line,
 436                                          &image[line * (epd->width / 8)],
 437                                          0, NULL, stage);
 438                 }
 439         } else {
 440                 for (line = 0; line < epd->height; line++) {
 441                         size_t n = line * epd->width / 8;
 442
 443                         repaper_one_line(epd, line, &image[n], 0, &mask[n],
 444                                          stage);
 445                 }
 446         }
 447 }
 448
 449 static void repaper_frame_fixed_repeat(struct repaper_epd *epd, u8 fixed_value,
 450                                        enum repaper_stage stage)
 451 {
 452         u64 start = local_clock();
 453         u64 end = start + (epd->factored_stage_time * 1000 * 1000);
 454
 455         do {
 456                 repaper_frame_fixed(epd, fixed_value, stage);
 457         } while (local_clock() < end);
 458 }
 459
 460 static void repaper_frame_data_repeat(struct repaper_epd *epd, const u8 *image,
 461                                       const u8 *mask, enum repaper_stage stage)
 462 {
 463         u64 start = local_clock();
 464         u64 end = start + (epd->factored_stage_time * 1000 * 1000);
 465
 466         do {
 467                 repaper_frame_data(epd, image, mask, stage);
 468         } while (local_clock() < end);
 469 }
 470
 471 static void repaper_get_temperature(struct repaper_epd *epd)
 472 {
 473         int ret, temperature = 0;
 474         unsigned int factor10x;
 475
 476         if (!epd->thermal)
 477                 return;
 478
 479         ret = thermal_zone_get_temp(epd->thermal, &temperature);
 480         if (ret) {
 481                 DRM_DEV_ERROR(&epd->spi->dev, "Failed to get temperature (%d)\n", ret);
 482                 return;
 483         }
 484
 485         temperature /= 1000;
 486
 487         if (temperature <= -10)
 488                 factor10x = 170;
 489         else if (temperature <= -5)
 490                 factor10x = 120;
 491         else if (temperature <= 5)
 492                 factor10x = 80;
 493         else if (temperature <= 10)
 494                 factor10x = 40;
 495         else if (temperature <= 15)
 496                 factor10x = 30;
 497         else if (temperature <= 20)
 498                 factor10x = 20;
 499         else if (temperature <= 40)
 500                 factor10x = 10;
 501         else
 502                 factor10x = 7;
 503
 504         epd->factored_stage_time = epd->stage_time * factor10x / 10;
 505 }
 506
 507 static void repaper_gray8_to_mono_reversed(u8 *buf, u32 width, u32 height)
 508 {
 509         u8 *gray8 = buf, *mono = buf;
 510         int y, xb, i;
 511
 512         for (y = 0; y < height; y++)
 513                 for (xb = 0; xb < width / 8; xb++) {
 514                         u8 byte = 0x00;
 515
 516                         for (i = 0; i < 8; i++) {
 517                                 int x = xb * 8 + i;
 518
 519                                 byte >>= 1;
 520                                 if (gray8[y * width + x] >> 7)
 521                                         byte |= BIT(7);
 522                         }
 523                         *mono++ = byte;
 524                 }
 525 }
 526
 527 static int repaper_fb_dirty(struct drm_framebuffer *fb)
 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 repaper_epd *epd = drm_to_epd(fb->dev);
 532         struct drm_rect clip;
 533         int idx, ret = 0;
 534         u8 *buf = NULL;
 535
 536         if (!epd->enabled)
 537                 return 0;
 538
 539         if (!drm_dev_enter(fb->dev, &idx))
 540                 return -ENODEV;
 541
 542         /* repaper can't do partial updates */
 543         clip.x1 = 0;
 544         clip.x2 = fb->width;
 545         clip.y1 = 0;
 546         clip.y2 = fb->height;
 547
 548         repaper_get_temperature(epd);
 549
 550         DRM_DEBUG("Flushing [FB:%d] st=%ums\n", fb->base.id,
 551                   epd->factored_stage_time);
 552
 553         buf = kmalloc_array(fb->width, fb->height, GFP_KERNEL);
 554         if (!buf) {
 555                 ret = -ENOMEM;
 556                 goto out_exit;
 557         }
 558
 559         if (import_attach) {
 560                 ret = dma_buf_begin_cpu_access(import_attach->dmabuf,
 561                                                DMA_FROM_DEVICE);
 562                 if (ret)
 563                         goto out_free;
 564         }
 565
 566         drm_fb_xrgb8888_to_gray8(buf, cma_obj->vaddr, fb, &clip);
 567
 568         if (import_attach) {
 569                 ret = dma_buf_end_cpu_access(import_attach->dmabuf,
 570                                              DMA_FROM_DEVICE);
 571                 if (ret)
 572                         goto out_free;
 573         }
 574
 575         repaper_gray8_to_mono_reversed(buf, fb->width, fb->height);
 576
 577         if (epd->partial) {
 578                 repaper_frame_data_repeat(epd, buf, epd->current_frame,
 579                                           REPAPER_NORMAL);
 580         } else if (epd->cleared) {
 581                 repaper_frame_data_repeat(epd, epd->current_frame, NULL,
 582                                           REPAPER_COMPENSATE);
 583                 repaper_frame_data_repeat(epd, epd->current_frame, NULL,
 584                                           REPAPER_WHITE);
 585                 repaper_frame_data_repeat(epd, buf, NULL, REPAPER_INVERSE);
 586                 repaper_frame_data_repeat(epd, buf, NULL, REPAPER_NORMAL);
 587
 588                 epd->partial = true;
 589         } else {
 590                 /* Clear display (anything -> white) */
 591                 repaper_frame_fixed_repeat(epd, 0xff, REPAPER_COMPENSATE);
 592                 repaper_frame_fixed_repeat(epd, 0xff, REPAPER_WHITE);
 593                 repaper_frame_fixed_repeat(epd, 0xaa, REPAPER_INVERSE);
 594                 repaper_frame_fixed_repeat(epd, 0xaa, REPAPER_NORMAL);
 595
 596                 /* Assuming a clear (white) screen output an image */
 597                 repaper_frame_fixed_repeat(epd, 0xaa, REPAPER_COMPENSATE);
 598                 repaper_frame_fixed_repeat(epd, 0xaa, REPAPER_WHITE);
 599                 repaper_frame_data_repeat(epd, buf, NULL, REPAPER_INVERSE);
 600                 repaper_frame_data_repeat(epd, buf, NULL, REPAPER_NORMAL);
 601
 602                 epd->cleared = true;
 603                 epd->partial = true;
 604         }
 605
 606         memcpy(epd->current_frame, buf, fb->width * fb->height / 8);
 607
 608         /*
 609          * An extra frame write is needed if pixels are set in the bottom line,
 610          * or else grey lines rises up from the pixels
 611          */
 612         if (epd->pre_border_byte) {
 613                 unsigned int x;
 614
 615                 for (x = 0; x < (fb->width / 8); x++)
 616                         if (buf[x + (fb->width * (fb->height - 1) / 8)]) {
 617                                 repaper_frame_data_repeat(epd, buf,
 618                                                           epd->current_frame,
 619                                                           REPAPER_NORMAL);
 620                                 break;
 621                         }
 622         }
 623
 624 out_free:
 625         kfree(buf);
 626 out_exit:
 627         drm_dev_exit(idx);
 628
 629         return ret;
 630 }
 631
 632 static void power_off(struct repaper_epd *epd)
 633 {
 634         /* Turn off power and all signals */
 635         gpiod_set_value_cansleep(epd->reset, 0);
 636         gpiod_set_value_cansleep(epd->panel_on, 0);
 637         if (epd->border)
 638                 gpiod_set_value_cansleep(epd->border, 0);
 639
 640         /* Ensure SPI MOSI and CLOCK are Low before CS Low */
 641         repaper_spi_mosi_low(epd->spi);
 642
 643         /* Discharge pulse */
 644         gpiod_set_value_cansleep(epd->discharge, 1);
 645         msleep(150);
 646         gpiod_set_value_cansleep(epd->discharge, 0);
 647 }
 648
 649 static void repaper_pipe_enable(struct drm_simple_display_pipe *pipe,
 650                                 struct drm_crtc_state *crtc_state,
 651                                 struct drm_plane_state *plane_state)
 652 {
 653         struct repaper_epd *epd = drm_to_epd(pipe->crtc.dev);
 654         struct spi_device *spi = epd->spi;
 655         struct device *dev = &spi->dev;
 656         bool dc_ok = false;
 657         int i, ret, idx;
 658
 659         if (!drm_dev_enter(pipe->crtc.dev, &idx))
 660                 return;
 661
 662         DRM_DEBUG_DRIVER("\n");
 663
 664         /* Power up sequence */
 665         gpiod_set_value_cansleep(epd->reset, 0);
 666         gpiod_set_value_cansleep(epd->panel_on, 0);
 667         gpiod_set_value_cansleep(epd->discharge, 0);
 668         if (epd->border)
 669                 gpiod_set_value_cansleep(epd->border, 0);
 670         repaper_spi_mosi_low(spi);
 671         usleep_range(5000, 10000);
 672
 673         gpiod_set_value_cansleep(epd->panel_on, 1);
 674         /*
 675          * This delay comes from the repaper.org userspace driver, it's not
 676          * mentioned in the datasheet.
 677          */
 678         usleep_range(10000, 15000);
 679         gpiod_set_value_cansleep(epd->reset, 1);
 680         if (epd->border)
 681                 gpiod_set_value_cansleep(epd->border, 1);
 682         usleep_range(5000, 10000);
 683         gpiod_set_value_cansleep(epd->reset, 0);
 684         usleep_range(5000, 10000);
 685         gpiod_set_value_cansleep(epd->reset, 1);
 686         usleep_range(5000, 10000);
 687
 688         /* Wait for COG to become ready */
 689         for (i = 100; i > 0; i--) {
 690                 if (!gpiod_get_value_cansleep(epd->busy))
 691                         break;
 692
 693                 usleep_range(10, 100);
 694         }
 695
 696         if (!i) {
 697                 DRM_DEV_ERROR(dev, "timeout waiting for panel to become ready.\n");
 698                 power_off(epd);
 699                 goto out_exit;
 700         }
 701
 702         repaper_read_id(spi);
 703         ret = repaper_read_id(spi);
 704         if (ret != REPAPER_RID_G2_COG_ID) {
 705                 if (ret < 0)
 706                         dev_err(dev, "failed to read chip (%d)\n", ret);
 707                 else
 708                         dev_err(dev, "wrong COG ID 0x%02x\n", ret);
 709                 power_off(epd);
 710                 goto out_exit;
 711         }
 712
 713         /* Disable OE */
 714         repaper_write_val(spi, 0x02, 0x40);
 715
 716         ret = repaper_read_val(spi, 0x0f);
 717         if (ret < 0 || !(ret & 0x80)) {
 718                 if (ret < 0)
 719                         DRM_DEV_ERROR(dev, "failed to read chip (%d)\n", ret);
 720                 else
 721                         DRM_DEV_ERROR(dev, "panel is reported broken\n");
 722                 power_off(epd);
 723                 goto out_exit;
 724         }
 725
 726         /* Power saving mode */
 727         repaper_write_val(spi, 0x0b, 0x02);
 728         /* Channel select */
 729         repaper_write_buf(spi, 0x01, epd->channel_select, 8);
 730         /* High power mode osc */
 731         repaper_write_val(spi, 0x07, 0xd1);
 732         /* Power setting */
 733         repaper_write_val(spi, 0x08, 0x02);
 734         /* Vcom level */
 735         repaper_write_val(spi, 0x09, 0xc2);
 736         /* Power setting */
 737         repaper_write_val(spi, 0x04, 0x03);
 738         /* Driver latch on */
 739         repaper_write_val(spi, 0x03, 0x01);
 740         /* Driver latch off */
 741         repaper_write_val(spi, 0x03, 0x00);
 742         usleep_range(5000, 10000);
 743
 744         /* Start chargepump */
 745         for (i = 0; i < 4; ++i) {
 746                 /* Charge pump positive voltage on - VGH/VDL on */
 747                 repaper_write_val(spi, 0x05, 0x01);
 748                 msleep(240);
 749
 750                 /* Charge pump negative voltage on - VGL/VDL on */
 751                 repaper_write_val(spi, 0x05, 0x03);
 752                 msleep(40);
 753
 754                 /* Charge pump Vcom on - Vcom driver on */
 755                 repaper_write_val(spi, 0x05, 0x0f);
 756                 msleep(40);
 757
 758                 /* check DC/DC */
 759                 ret = repaper_read_val(spi, 0x0f);
 760                 if (ret < 0) {
 761                         DRM_DEV_ERROR(dev, "failed to read chip (%d)\n", ret);
 762                         power_off(epd);
 763                         goto out_exit;
 764                 }
 765
 766                 if (ret & 0x40) {
 767                         dc_ok = true;
 768                         break;
 769                 }
 770         }
 771
 772         if (!dc_ok) {
 773                 DRM_DEV_ERROR(dev, "dc/dc failed\n");
 774                 power_off(epd);
 775                 goto out_exit;
 776         }
 777
 778         /*
 779          * Output enable to disable
 780          * The userspace driver sets this to 0x04, but the datasheet says 0x06
 781          */
 782         repaper_write_val(spi, 0x02, 0x04);
 783
 784         epd->enabled = true;
 785         epd->partial = false;
 786 out_exit:
 787         drm_dev_exit(idx);
 788 }
 789
 790 static void repaper_pipe_disable(struct drm_simple_display_pipe *pipe)
 791 {
 792         struct repaper_epd *epd = drm_to_epd(pipe->crtc.dev);
 793         struct spi_device *spi = epd->spi;
 794         unsigned int line;
 795
 796         /*
 797          * This callback is not protected by drm_dev_enter/exit since we want to
 798          * turn off the display on regular driver unload. It's highly unlikely
 799          * that the underlying SPI controller is gone should this be called after
 800          * unplug.
 801          */
 802
 803         if (!epd->enabled)
 804                 return;
 805
 806         DRM_DEBUG_DRIVER("\n");
 807
 808         epd->enabled = false;
 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 void repaper_pipe_update(struct drm_simple_display_pipe *pipe,
 852                                 struct drm_plane_state *old_state)
 853 {
 854         struct drm_plane_state *state = pipe->plane.state;
 855         struct drm_crtc *crtc = &pipe->crtc;
 856         struct drm_rect rect;
 857
 858         if (drm_atomic_helper_damage_merged(old_state, state, &rect))
 859                 repaper_fb_dirty(state->fb);
 860
 861         if (crtc->state->event) {
 862                 spin_lock_irq(&crtc->dev->event_lock);
 863                 drm_crtc_send_vblank_event(crtc, crtc->state->event);
 864                 spin_unlock_irq(&crtc->dev->event_lock);
 865                 crtc->state->event = NULL;
 866         }
 867 }
 868
 869 static const struct drm_simple_display_pipe_funcs repaper_pipe_funcs = {
 870         .enable = repaper_pipe_enable,
 871         .disable = repaper_pipe_disable,
 872         .update = repaper_pipe_update,
 873         .prepare_fb = drm_gem_fb_simple_display_pipe_prepare_fb,
 874 };
 875
 876 static const struct drm_mode_config_funcs repaper_mode_config_funcs = {
 877         .fb_create = drm_gem_fb_create_with_dirty,
 878         .atomic_check = drm_atomic_helper_check,
 879         .atomic_commit = drm_atomic_helper_commit,
 880 };
 881
 882 static void repaper_release(struct drm_device *drm)
 883 {
 884         struct repaper_epd *epd = drm_to_epd(drm);
 885
 886         DRM_DEBUG_DRIVER("\n");
 887
 888         drm_mode_config_cleanup(drm);
 889         drm_dev_fini(drm);
 890         kfree(epd);
 891 }
 892
 893 static const uint32_t repaper_formats[] = {
 894         DRM_FORMAT_XRGB8888,
 895 };
 896
 897 static const struct drm_display_mode repaper_e1144cs021_mode = {
 898         DRM_SIMPLE_MODE(128, 96, 29, 22),
 899 };
 900
 901 static const u8 repaper_e1144cs021_cs[] = { 0x00, 0x00, 0x00, 0x00,
 902                                             0x00, 0x0f, 0xff, 0x00 };
 903
 904 static const struct drm_display_mode repaper_e1190cs021_mode = {
 905         DRM_SIMPLE_MODE(144, 128, 36, 32),
 906 };
 907
 908 static const u8 repaper_e1190cs021_cs[] = { 0x00, 0x00, 0x00, 0x03,
 909                                             0xfc, 0x00, 0x00, 0xff };
 910
 911 static const struct drm_display_mode repaper_e2200cs021_mode = {
 912         DRM_SIMPLE_MODE(200, 96, 46, 22),
 913 };
 914
 915 static const u8 repaper_e2200cs021_cs[] = { 0x00, 0x00, 0x00, 0x00,
 916                                             0x01, 0xff, 0xe0, 0x00 };
 917
 918 static const struct drm_display_mode repaper_e2271cs021_mode = {
 919         DRM_SIMPLE_MODE(264, 176, 57, 38),
 920 };
 921
 922 static const u8 repaper_e2271cs021_cs[] = { 0x00, 0x00, 0x00, 0x7f,
 923                                             0xff, 0xfe, 0x00, 0x00 };
 924
 925 DEFINE_DRM_GEM_CMA_FOPS(repaper_fops);
 926
 927 static struct drm_driver repaper_driver = {
 928         .driver_features        = DRIVER_GEM | DRIVER_MODESET | DRIVER_PRIME |
 929                                   DRIVER_ATOMIC,
 930         .fops                   = &repaper_fops,
 931         .release                = repaper_release,
 932         DRM_GEM_CMA_VMAP_DRIVER_OPS,
 933         .name                   = "repaper",
 934         .desc                   = "Pervasive Displays RePaper e-ink panels",
 935         .date                   = "20170405",
 936         .major                  = 1,
 937         .minor                  = 0,
 938 };
 939
 940 static const struct of_device_id repaper_of_match[] = {
 941         { .compatible = "pervasive,e1144cs021", .data = (void *)E1144CS021 },
 942         { .compatible = "pervasive,e1190cs021", .data = (void *)E1190CS021 },
 943         { .compatible = "pervasive,e2200cs021", .data = (void *)E2200CS021 },
 944         { .compatible = "pervasive,e2271cs021", .data = (void *)E2271CS021 },
 945         {},
 946 };
 947 MODULE_DEVICE_TABLE(of, repaper_of_match);
 948
 949 static const struct spi_device_id repaper_id[] = {
 950         { "e1144cs021", E1144CS021 },
 951         { "e1190cs021", E1190CS021 },
 952         { "e2200cs021", E2200CS021 },
 953         { "e2271cs021", E2271CS021 },
 954         { },
 955 };
 956 MODULE_DEVICE_TABLE(spi, repaper_id);
 957
 958 static int repaper_probe(struct spi_device *spi)
 959 {
 960         const struct drm_display_mode *mode;
 961         const struct spi_device_id *spi_id;
 962         const struct of_device_id *match;
 963         struct device *dev = &spi->dev;
 964         enum repaper_model model;
 965         const char *thermal_zone;
 966         struct repaper_epd *epd;
 967         size_t line_buffer_size;
 968         struct drm_device *drm;
 969         int ret;
 970
 971         match = of_match_device(repaper_of_match, dev);
 972         if (match) {
 973                 model = (enum repaper_model)match->data;
 974         } else {
 975                 spi_id = spi_get_device_id(spi);
 976                 model = spi_id->driver_data;
 977         }
 978
 979         /* The SPI device is used to allocate dma memory */
 980         if (!dev->coherent_dma_mask) {
 981                 ret = dma_coerce_mask_and_coherent(dev, DMA_BIT_MASK(32));
 982                 if (ret) {
 983                         dev_warn(dev, "Failed to set dma mask %d\n", ret);
 984                         return ret;
 985                 }
 986         }
 987
 988         epd = kzalloc(sizeof(*epd), GFP_KERNEL);
 989         if (!epd)
 990                 return -ENOMEM;
 991
 992         drm = &epd->drm;
 993
 994         ret = devm_drm_dev_init(dev, drm, &repaper_driver);
 995         if (ret) {
 996                 kfree(epd);
 997                 return ret;
 998         }
 999
1000         drm_mode_config_init(drm);
1001         drm->mode_config.funcs = &repaper_mode_config_funcs;
1002
1003         epd->spi = spi;
1004
1005         epd->panel_on = devm_gpiod_get(dev, "panel-on", GPIOD_OUT_LOW);
1006         if (IS_ERR(epd->panel_on)) {
1007                 ret = PTR_ERR(epd->panel_on);
1008                 if (ret != -EPROBE_DEFER)
1009                         DRM_DEV_ERROR(dev, "Failed to get gpio 'panel-on'\n");
1010                 return ret;
1011         }
1012
1013         epd->discharge = devm_gpiod_get(dev, "discharge", GPIOD_OUT_LOW);
1014         if (IS_ERR(epd->discharge)) {
1015                 ret = PTR_ERR(epd->discharge);
1016                 if (ret != -EPROBE_DEFER)
1017                         DRM_DEV_ERROR(dev, "Failed to get gpio 'discharge'\n");
1018                 return ret;
1019         }
1020
1021         epd->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
1022         if (IS_ERR(epd->reset)) {
1023                 ret = PTR_ERR(epd->reset);
1024                 if (ret != -EPROBE_DEFER)
1025                         DRM_DEV_ERROR(dev, "Failed to get gpio 'reset'\n");
1026                 return ret;
1027         }
1028
1029         epd->busy = devm_gpiod_get(dev, "busy", GPIOD_IN);
1030         if (IS_ERR(epd->busy)) {
1031                 ret = PTR_ERR(epd->busy);
1032                 if (ret != -EPROBE_DEFER)
1033                         DRM_DEV_ERROR(dev, "Failed to get gpio 'busy'\n");
1034                 return ret;
1035         }
1036
1037         if (!device_property_read_string(dev, "pervasive,thermal-zone",
1038                                          &thermal_zone)) {
1039                 epd->thermal = thermal_zone_get_zone_by_name(thermal_zone);
1040                 if (IS_ERR(epd->thermal)) {
1041                         DRM_DEV_ERROR(dev, "Failed to get thermal zone: %s\n", thermal_zone);
1042                         return PTR_ERR(epd->thermal);
1043                 }
1044         }
1045
1046         switch (model) {
1047         case E1144CS021:
1048                 mode = &repaper_e1144cs021_mode;
1049                 epd->channel_select = repaper_e1144cs021_cs;
1050                 epd->stage_time = 480;
1051                 epd->bytes_per_scan = 96 / 4;
1052                 epd->middle_scan = true; /* data-scan-data */
1053                 epd->pre_border_byte = false;
1054                 epd->border_byte = REPAPER_BORDER_BYTE_ZERO;
1055                 break;
1056
1057         case E1190CS021:
1058                 mode = &repaper_e1190cs021_mode;
1059                 epd->channel_select = repaper_e1190cs021_cs;
1060                 epd->stage_time = 480;
1061                 epd->bytes_per_scan = 128 / 4 / 2;
1062                 epd->middle_scan = false; /* scan-data-scan */
1063                 epd->pre_border_byte = false;
1064                 epd->border_byte = REPAPER_BORDER_BYTE_SET;
1065                 break;
1066
1067         case E2200CS021:
1068                 mode = &repaper_e2200cs021_mode;
1069                 epd->channel_select = repaper_e2200cs021_cs;
1070                 epd->stage_time = 480;
1071                 epd->bytes_per_scan = 96 / 4;
1072                 epd->middle_scan = true; /* data-scan-data */
1073                 epd->pre_border_byte = true;
1074                 epd->border_byte = REPAPER_BORDER_BYTE_NONE;
1075                 break;
1076
1077         case E2271CS021:
1078                 epd->border = devm_gpiod_get(dev, "border", GPIOD_OUT_LOW);
1079                 if (IS_ERR(epd->border)) {
1080                         ret = PTR_ERR(epd->border);
1081                         if (ret != -EPROBE_DEFER)
1082                                 DRM_DEV_ERROR(dev, "Failed to get gpio 'border'\n");
1083                         return ret;
1084                 }
1085
1086                 mode = &repaper_e2271cs021_mode;
1087                 epd->channel_select = repaper_e2271cs021_cs;
1088                 epd->stage_time = 630;
1089                 epd->bytes_per_scan = 176 / 4;
1090                 epd->middle_scan = true; /* data-scan-data */
1091                 epd->pre_border_byte = true;
1092                 epd->border_byte = REPAPER_BORDER_BYTE_NONE;
1093                 break;
1094
1095         default:
1096                 return -ENODEV;
1097         }
1098
1099         epd->width = mode->hdisplay;
1100         epd->height = mode->vdisplay;
1101         epd->factored_stage_time = epd->stage_time;
1102
1103         line_buffer_size = 2 * epd->width / 8 + epd->bytes_per_scan + 2;
1104         epd->line_buffer = devm_kzalloc(dev, line_buffer_size, GFP_KERNEL);
1105         if (!epd->line_buffer)
1106                 return -ENOMEM;
1107
1108         epd->current_frame = devm_kzalloc(dev, epd->width * epd->height / 8,
1109                                           GFP_KERNEL);
1110         if (!epd->current_frame)
1111                 return -ENOMEM;
1112
1113         ret = tinydrm_display_pipe_init(drm, &epd->pipe, &repaper_pipe_funcs,
1114                                         DRM_MODE_CONNECTOR_VIRTUAL,
1115                                         repaper_formats,
1116                                         ARRAY_SIZE(repaper_formats), mode, 0);
1117         if (ret)
1118                 return ret;
1119
1120         drm_mode_config_reset(drm);
1121
1122         ret = drm_dev_register(drm, 0);
1123         if (ret)
1124                 return ret;
1125
1126         spi_set_drvdata(spi, drm);
1127
1128         DRM_DEBUG_DRIVER("SPI speed: %uMHz\n", spi->max_speed_hz / 1000000);
1129
1130         drm_fbdev_generic_setup(drm, 0);
1131
1132         return 0;
1133 }
1134
1135 static int repaper_remove(struct spi_device *spi)
1136 {
1137         struct drm_device *drm = spi_get_drvdata(spi);
1138
1139         drm_dev_unplug(drm);
1140         drm_atomic_helper_shutdown(drm);
1141
1142         return 0;
1143 }
1144
1145 static void repaper_shutdown(struct spi_device *spi)
1146 {
1147         drm_atomic_helper_shutdown(spi_get_drvdata(spi));
1148 }
1149
1150 static struct spi_driver repaper_spi_driver = {
1151         .driver = {
1152                 .name = "repaper",
1153                 .owner = THIS_MODULE,
1154                 .of_match_table = repaper_of_match,
1155         },
1156         .id_table = repaper_id,
1157         .probe = repaper_probe,
1158         .remove = repaper_remove,
1159         .shutdown = repaper_shutdown,
1160 };
1161 module_spi_driver(repaper_spi_driver);
1162
1163 MODULE_DESCRIPTION("Pervasive Displays RePaper DRM driver");
1164 MODULE_AUTHOR("Noralf Trønnes");
1165 MODULE_LICENSE("GPL");