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