drivers/gpu/drm/tiny/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/gpio/consumer.h>
  18 #include <linux/module.h>
  19 #include <linux/property.h>
  20 #include <linux/sched/clock.h>
  21 #include <linux/spi/spi.h>
  22 #include <linux/thermal.h>
  23
  24 #include <drm/clients/drm_client_setup.h>
  25 #include <drm/drm_atomic_helper.h>
  26 #include <drm/drm_connector.h>
  27 #include <drm/drm_damage_helper.h>
  28 #include <drm/drm_drv.h>
  29 #include <drm/drm_fb_dma_helper.h>
  30 #include <drm/drm_fbdev_dma.h>
  31 #include <drm/drm_format_helper.h>
  32 #include <drm/drm_framebuffer.h>
  33 #include <drm/drm_gem_atomic_helper.h>
  34 #include <drm/drm_gem_dma_helper.h>
  35 #include <drm/drm_gem_framebuffer_helper.h>
  36 #include <drm/drm_managed.h>
  37 #include <drm/drm_modes.h>
  38 #include <drm/drm_rect.h>
  39 #include <drm/drm_probe_helper.h>
  40 #include <drm/drm_simple_kms_helper.h>
  41
  42 #define REPAPER_RID_G2_COG_ID   0x12
  43
  44 enum repaper_model {
  45         /* 0 is reserved to avoid clashing with NULL */
  46         E1144CS021 = 1,
  47         E1190CS021,
  48         E2200CS021,
  49         E2271CS021,
  50 };
  51
  52 enum repaper_stage {         /* Image pixel -> Display pixel */
  53         REPAPER_COMPENSATE,  /* B -> W, W -> B (Current Image) */
  54         REPAPER_WHITE,       /* B -> N, W -> W (Current Image) */
  55         REPAPER_INVERSE,     /* B -> N, W -> B (New Image) */
  56         REPAPER_NORMAL       /* B -> B, W -> W (New Image) */
  57 };
  58
  59 enum repaper_epd_border_byte {
  60         REPAPER_BORDER_BYTE_NONE,
  61         REPAPER_BORDER_BYTE_ZERO,
  62         REPAPER_BORDER_BYTE_SET,
  63 };
  64
  65 struct repaper_epd {
  66         struct drm_device drm;
  67         struct drm_simple_display_pipe pipe;
  68         const struct drm_display_mode *mode;
  69         struct drm_connector connector;
  70         struct spi_device *spi;
  71
  72         struct gpio_desc *panel_on;
  73         struct gpio_desc *border;
  74         struct gpio_desc *discharge;
  75         struct gpio_desc *reset;
  76         struct gpio_desc *busy;
  77
  78         struct thermal_zone_device *thermal;
  79
  80         unsigned int height;
  81         unsigned int width;
  82         unsigned int bytes_per_scan;
  83         const u8 *channel_select;
  84         unsigned int stage_time;
  85         unsigned int factored_stage_time;
  86         bool middle_scan;
  87         bool pre_border_byte;
  88         enum repaper_epd_border_byte border_byte;
  89
  90         u8 *line_buffer;
  91         void *current_frame;
  92
  93         bool cleared;
  94         bool partial;
  95 };
  96
  97 static inline struct repaper_epd *drm_to_epd(struct drm_device *drm)
  98 {
  99         return container_of(drm, struct repaper_epd, drm);
 100 }
 101
 102 static int repaper_spi_transfer(struct spi_device *spi, u8 header,
 103                                 const void *tx, void *rx, size_t len)
 104 {
 105         void *txbuf = NULL, *rxbuf = NULL;
 106         struct spi_transfer tr[2] = {};
 107         u8 *headerbuf;
 108         int ret;
 109
 110         headerbuf = kmalloc(1, GFP_KERNEL);
 111         if (!headerbuf)
 112                 return -ENOMEM;
 113
 114         headerbuf[0] = header;
 115         tr[0].tx_buf = headerbuf;
 116         tr[0].len = 1;
 117
 118         /* Stack allocated tx? */
 119         if (tx && len <= 32) {
 120                 txbuf = kmemdup(tx, len, GFP_KERNEL);
 121                 if (!txbuf) {
 122                         ret = -ENOMEM;
 123                         goto out_free;
 124                 }
 125         }
 126
 127         if (rx) {
 128                 rxbuf = kmalloc(len, GFP_KERNEL);
 129                 if (!rxbuf) {
 130                         ret = -ENOMEM;
 131                         goto out_free;
 132                 }
 133         }
 134
 135         tr[1].tx_buf = txbuf ? txbuf : tx;
 136         tr[1].rx_buf = rxbuf;
 137         tr[1].len = len;
 138
 139         ndelay(80);
 140         ret = spi_sync_transfer(spi, tr, 2);
 141         if (rx && !ret)
 142                 memcpy(rx, rxbuf, len);
 143
 144 out_free:
 145         kfree(headerbuf);
 146         kfree(txbuf);
 147         kfree(rxbuf);
 148
 149         return ret;
 150 }
 151
 152 static int repaper_write_buf(struct spi_device *spi, u8 reg,
 153                              const u8 *buf, size_t len)
 154 {
 155         int ret;
 156
 157         ret = repaper_spi_transfer(spi, 0x70, &reg, NULL, 1);
 158         if (ret)
 159                 return ret;
 160
 161         return repaper_spi_transfer(spi, 0x72, buf, NULL, len);
 162 }
 163
 164 static int repaper_write_val(struct spi_device *spi, u8 reg, u8 val)
 165 {
 166         return repaper_write_buf(spi, reg, &val, 1);
 167 }
 168
 169 static int repaper_read_val(struct spi_device *spi, u8 reg)
 170 {
 171         int ret;
 172         u8 val;
 173
 174         ret = repaper_spi_transfer(spi, 0x70, &reg, NULL, 1);
 175         if (ret)
 176                 return ret;
 177
 178         ret = repaper_spi_transfer(spi, 0x73, NULL, &val, 1);
 179
 180         return ret ? ret : val;
 181 }
 182
 183 static int repaper_read_id(struct spi_device *spi)
 184 {
 185         int ret;
 186         u8 id;
 187
 188         ret = repaper_spi_transfer(spi, 0x71, NULL, &id, 1);
 189
 190         return ret ? ret : id;
 191 }
 192
 193 static void repaper_spi_mosi_low(struct spi_device *spi)
 194 {
 195         const u8 buf[1] = { 0 };
 196
 197         spi_write(spi, buf, 1);
 198 }
 199
 200 /* pixels on display are numbered from 1 so even is actually bits 1,3,5,... */
 201 static void repaper_even_pixels(struct repaper_epd *epd, u8 **pp,
 202                                 const u8 *data, u8 fixed_value, const u8 *mask,
 203                                 enum repaper_stage stage)
 204 {
 205         unsigned int b;
 206
 207         for (b = 0; b < (epd->width / 8); b++) {
 208                 if (data) {
 209                         u8 pixels = data[b] & 0xaa;
 210                         u8 pixel_mask = 0xff;
 211                         u8 p1, p2, p3, p4;
 212
 213                         if (mask) {
 214                                 pixel_mask = (mask[b] ^ pixels) & 0xaa;
 215                                 pixel_mask |= pixel_mask >> 1;
 216                         }
 217
 218                         switch (stage) {
 219                         case REPAPER_COMPENSATE: /* B -> W, W -> B (Current) */
 220                                 pixels = 0xaa | ((pixels ^ 0xaa) >> 1);
 221                                 break;
 222                         case REPAPER_WHITE:      /* B -> N, W -> W (Current) */
 223                                 pixels = 0x55 + ((pixels ^ 0xaa) >> 1);
 224                                 break;
 225                         case REPAPER_INVERSE:    /* B -> N, W -> B (New) */
 226                                 pixels = 0x55 | (pixels ^ 0xaa);
 227                                 break;
 228                         case REPAPER_NORMAL:     /* B -> B, W -> W (New) */
 229                                 pixels = 0xaa | (pixels >> 1);
 230                                 break;
 231                         }
 232
 233                         pixels = (pixels & pixel_mask) | (~pixel_mask & 0x55);
 234                         p1 = (pixels >> 6) & 0x03;
 235                         p2 = (pixels >> 4) & 0x03;
 236                         p3 = (pixels >> 2) & 0x03;
 237                         p4 = (pixels >> 0) & 0x03;
 238                         pixels = (p1 << 0) | (p2 << 2) | (p3 << 4) | (p4 << 6);
 239                         *(*pp)++ = pixels;
 240                 } else {
 241                         *(*pp)++ = fixed_value;
 242                 }
 243         }
 244 }
 245
 246 /* pixels on display are numbered from 1 so odd is actually bits 0,2,4,... */
 247 static void repaper_odd_pixels(struct repaper_epd *epd, u8 **pp,
 248                                const u8 *data, u8 fixed_value, const u8 *mask,
 249                                enum repaper_stage stage)
 250 {
 251         unsigned int b;
 252
 253         for (b = epd->width / 8; b > 0; b--) {
 254                 if (data) {
 255                         u8 pixels = data[b - 1] & 0x55;
 256                         u8 pixel_mask = 0xff;
 257
 258                         if (mask) {
 259                                 pixel_mask = (mask[b - 1] ^ pixels) & 0x55;
 260                                 pixel_mask |= pixel_mask << 1;
 261                         }
 262
 263                         switch (stage) {
 264                         case REPAPER_COMPENSATE: /* B -> W, W -> B (Current) */
 265                                 pixels = 0xaa | (pixels ^ 0x55);
 266                                 break;
 267                         case REPAPER_WHITE:      /* B -> N, W -> W (Current) */
 268                                 pixels = 0x55 + (pixels ^ 0x55);
 269                                 break;
 270                         case REPAPER_INVERSE:    /* B -> N, W -> B (New) */
 271                                 pixels = 0x55 | ((pixels ^ 0x55) << 1);
 272                                 break;
 273                         case REPAPER_NORMAL:     /* B -> B, W -> W (New) */
 274                                 pixels = 0xaa | pixels;
 275                                 break;
 276                         }
 277
 278                         pixels = (pixels & pixel_mask) | (~pixel_mask & 0x55);
 279                         *(*pp)++ = pixels;
 280                 } else {
 281                         *(*pp)++ = fixed_value;
 282                 }
 283         }
 284 }
 285
 286 /* interleave bits: (byte)76543210 -> (16 bit).7.6.5.4.3.2.1 */
 287 static inline u16 repaper_interleave_bits(u16 value)
 288 {
 289         value = (value | (value << 4)) & 0x0f0f;
 290         value = (value | (value << 2)) & 0x3333;
 291         value = (value | (value << 1)) & 0x5555;
 292
 293         return value;
 294 }
 295
 296 /* pixels on display are numbered from 1 */
 297 static void repaper_all_pixels(struct repaper_epd *epd, u8 **pp,
 298                                const u8 *data, u8 fixed_value, const u8 *mask,
 299                                enum repaper_stage stage)
 300 {
 301         unsigned int b;
 302
 303         for (b = epd->width / 8; b > 0; b--) {
 304                 if (data) {
 305                         u16 pixels = repaper_interleave_bits(data[b - 1]);
 306                         u16 pixel_mask = 0xffff;
 307
 308                         if (mask) {
 309                                 pixel_mask = repaper_interleave_bits(mask[b - 1]);
 310
 311                                 pixel_mask = (pixel_mask ^ pixels) & 0x5555;
 312                                 pixel_mask |= pixel_mask << 1;
 313                         }
 314
 315                         switch (stage) {
 316                         case REPAPER_COMPENSATE: /* B -> W, W -> B (Current) */
 317                                 pixels = 0xaaaa | (pixels ^ 0x5555);
 318                                 break;
 319                         case REPAPER_WHITE:      /* B -> N, W -> W (Current) */
 320                                 pixels = 0x5555 + (pixels ^ 0x5555);
 321                                 break;
 322                         case REPAPER_INVERSE:    /* B -> N, W -> B (New) */
 323                                 pixels = 0x5555 | ((pixels ^ 0x5555) << 1);
 324                                 break;
 325                         case REPAPER_NORMAL:     /* B -> B, W -> W (New) */
 326                                 pixels = 0xaaaa | pixels;
 327                                 break;
 328                         }
 329
 330                         pixels = (pixels & pixel_mask) | (~pixel_mask & 0x5555);
 331                         *(*pp)++ = pixels >> 8;
 332                         *(*pp)++ = pixels;
 333                 } else {
 334                         *(*pp)++ = fixed_value;
 335                         *(*pp)++ = fixed_value;
 336                 }
 337         }
 338 }
 339
 340 /* output one line of scan and data bytes to the display */
 341 static void repaper_one_line(struct repaper_epd *epd, unsigned int line,
 342                              const u8 *data, u8 fixed_value, const u8 *mask,
 343                              enum repaper_stage stage)
 344 {
 345         u8 *p = epd->line_buffer;
 346         unsigned int b;
 347
 348         repaper_spi_mosi_low(epd->spi);
 349
 350         if (epd->pre_border_byte)
 351                 *p++ = 0x00;
 352
 353         if (epd->middle_scan) {
 354                 /* data bytes */
 355                 repaper_odd_pixels(epd, &p, data, fixed_value, mask, stage);
 356
 357                 /* scan line */
 358                 for (b = epd->bytes_per_scan; b > 0; b--) {
 359                         if (line / 4 == b - 1)
 360                                 *p++ = 0x03 << (2 * (line & 0x03));
 361                         else
 362                                 *p++ = 0x00;
 363                 }
 364
 365                 /* data bytes */
 366                 repaper_even_pixels(epd, &p, data, fixed_value, mask, stage);
 367         } else {
 368                 /*
 369                  * even scan line, but as lines on display are numbered from 1,
 370                  * line: 1,3,5,...
 371                  */
 372                 for (b = 0; b < epd->bytes_per_scan; b++) {
 373                         if (0 != (line & 0x01) && line / 8 == b)
 374                                 *p++ = 0xc0 >> (line & 0x06);
 375                         else
 376                                 *p++ = 0x00;
 377                 }
 378
 379                 /* data bytes */
 380                 repaper_all_pixels(epd, &p, data, fixed_value, mask, stage);
 381
 382                 /*
 383                  * odd scan line, but as lines on display are numbered from 1,
 384                  * line: 0,2,4,6,...
 385                  */
 386                 for (b = epd->bytes_per_scan; b > 0; b--) {
 387                         if (0 == (line & 0x01) && line / 8 == b - 1)
 388                                 *p++ = 0x03 << (line & 0x06);
 389                         else
 390                                 *p++ = 0x00;
 391                 }
 392         }
 393
 394         switch (epd->border_byte) {
 395         case REPAPER_BORDER_BYTE_NONE:
 396                 break;
 397
 398         case REPAPER_BORDER_BYTE_ZERO:
 399                 *p++ = 0x00;
 400                 break;
 401
 402         case REPAPER_BORDER_BYTE_SET:
 403                 switch (stage) {
 404                 case REPAPER_COMPENSATE:
 405                 case REPAPER_WHITE:
 406                 case REPAPER_INVERSE:
 407                         *p++ = 0x00;
 408                         break;
 409                 case REPAPER_NORMAL:
 410                         *p++ = 0xaa;
 411                         break;
 412                 }
 413                 break;
 414         }
 415
 416         repaper_write_buf(epd->spi, 0x0a, epd->line_buffer,
 417                           p - epd->line_buffer);
 418
 419         /* Output data to panel */
 420         repaper_write_val(epd->spi, 0x02, 0x07);
 421
 422         repaper_spi_mosi_low(epd->spi);
 423 }
 424
 425 static void repaper_frame_fixed(struct repaper_epd *epd, u8 fixed_value,
 426                                 enum repaper_stage stage)
 427 {
 428         unsigned int line;
 429
 430         for (line = 0; line < epd->height; line++)
 431                 repaper_one_line(epd, line, NULL, fixed_value, NULL, stage);
 432 }
 433
 434 static void repaper_frame_data(struct repaper_epd *epd, const u8 *image,
 435                                const u8 *mask, enum repaper_stage stage)
 436 {
 437         unsigned int line;
 438
 439         if (!mask) {
 440                 for (line = 0; line < epd->height; line++) {
 441                         repaper_one_line(epd, line,
 442                                          &image[line * (epd->width / 8)],
 443                                          0, NULL, stage);
 444                 }
 445         } else {
 446                 for (line = 0; line < epd->height; line++) {
 447                         size_t n = line * epd->width / 8;
 448
 449                         repaper_one_line(epd, line, &image[n], 0, &mask[n],
 450                                          stage);
 451                 }
 452         }
 453 }
 454
 455 static void repaper_frame_fixed_repeat(struct repaper_epd *epd, u8 fixed_value,
 456                                        enum repaper_stage stage)
 457 {
 458         u64 start = local_clock();
 459         u64 end = start + (epd->factored_stage_time * 1000 * 1000);
 460
 461         do {
 462                 repaper_frame_fixed(epd, fixed_value, stage);
 463         } while (local_clock() < end);
 464 }
 465
 466 static void repaper_frame_data_repeat(struct repaper_epd *epd, const u8 *image,
 467                                       const u8 *mask, enum repaper_stage stage)
 468 {
 469         u64 start = local_clock();
 470         u64 end = start + (epd->factored_stage_time * 1000 * 1000);
 471
 472         do {
 473                 repaper_frame_data(epd, image, mask, stage);
 474         } while (local_clock() < end);
 475 }
 476
 477 static void repaper_get_temperature(struct repaper_epd *epd)
 478 {
 479         int ret, temperature = 0;
 480         unsigned int factor10x;
 481
 482         if (!epd->thermal)
 483                 return;
 484
 485         ret = thermal_zone_get_temp(epd->thermal, &temperature);
 486         if (ret) {
 487                 DRM_DEV_ERROR(&epd->spi->dev, "Failed to get temperature (%d)\n", ret);
 488                 return;
 489         }
 490
 491         temperature /= 1000;
 492
 493         if (temperature <= -10)
 494                 factor10x = 170;
 495         else if (temperature <= -5)
 496                 factor10x = 120;
 497         else if (temperature <= 5)
 498                 factor10x = 80;
 499         else if (temperature <= 10)
 500                 factor10x = 40;
 501         else if (temperature <= 15)
 502                 factor10x = 30;
 503         else if (temperature <= 20)
 504                 factor10x = 20;
 505         else if (temperature <= 40)
 506                 factor10x = 10;
 507         else
 508                 factor10x = 7;
 509
 510         epd->factored_stage_time = epd->stage_time * factor10x / 10;
 511 }
 512
 513 static int repaper_fb_dirty(struct drm_framebuffer *fb,
 514                             struct drm_format_conv_state *fmtcnv_state)
 515 {
 516         struct drm_gem_dma_object *dma_obj = drm_fb_dma_get_gem_obj(fb, 0);
 517         struct repaper_epd *epd = drm_to_epd(fb->dev);
 518         unsigned int dst_pitch = 0;
 519         struct iosys_map dst, vmap;
 520         struct drm_rect clip;
 521         int idx, ret = 0;
 522         u8 *buf = NULL;
 523
 524         if (!drm_dev_enter(fb->dev, &idx))
 525                 return -ENODEV;
 526
 527         /* repaper can't do partial updates */
 528         clip.x1 = 0;
 529         clip.x2 = fb->width;
 530         clip.y1 = 0;
 531         clip.y2 = fb->height;
 532
 533         repaper_get_temperature(epd);
 534
 535         DRM_DEBUG("Flushing [FB:%d] st=%ums\n", fb->base.id,
 536                   epd->factored_stage_time);
 537
 538         buf = kmalloc(fb->width * fb->height / 8, GFP_KERNEL);
 539         if (!buf) {
 540                 ret = -ENOMEM;
 541                 goto out_exit;
 542         }
 543
 544         ret = drm_gem_fb_begin_cpu_access(fb, DMA_FROM_DEVICE);
 545         if (ret)
 546                 goto out_free;
 547
 548         iosys_map_set_vaddr(&dst, buf);
 549         iosys_map_set_vaddr(&vmap, dma_obj->vaddr);
 550         drm_fb_xrgb8888_to_mono(&dst, &dst_pitch, &vmap, fb, &clip, fmtcnv_state);
 551
 552         drm_gem_fb_end_cpu_access(fb, DMA_FROM_DEVICE);
 553
 554         if (epd->partial) {
 555                 repaper_frame_data_repeat(epd, buf, epd->current_frame,
 556                                           REPAPER_NORMAL);
 557         } else if (epd->cleared) {
 558                 repaper_frame_data_repeat(epd, epd->current_frame, NULL,
 559                                           REPAPER_COMPENSATE);
 560                 repaper_frame_data_repeat(epd, epd->current_frame, NULL,
 561                                           REPAPER_WHITE);
 562                 repaper_frame_data_repeat(epd, buf, NULL, REPAPER_INVERSE);
 563                 repaper_frame_data_repeat(epd, buf, NULL, REPAPER_NORMAL);
 564
 565                 epd->partial = true;
 566         } else {
 567                 /* Clear display (anything -> white) */
 568                 repaper_frame_fixed_repeat(epd, 0xff, REPAPER_COMPENSATE);
 569                 repaper_frame_fixed_repeat(epd, 0xff, REPAPER_WHITE);
 570                 repaper_frame_fixed_repeat(epd, 0xaa, REPAPER_INVERSE);
 571                 repaper_frame_fixed_repeat(epd, 0xaa, REPAPER_NORMAL);
 572
 573                 /* Assuming a clear (white) screen output an image */
 574                 repaper_frame_fixed_repeat(epd, 0xaa, REPAPER_COMPENSATE);
 575                 repaper_frame_fixed_repeat(epd, 0xaa, REPAPER_WHITE);
 576                 repaper_frame_data_repeat(epd, buf, NULL, REPAPER_INVERSE);
 577                 repaper_frame_data_repeat(epd, buf, NULL, REPAPER_NORMAL);
 578
 579                 epd->cleared = true;
 580                 epd->partial = true;
 581         }
 582
 583         memcpy(epd->current_frame, buf, fb->width * fb->height / 8);
 584
 585         /*
 586          * An extra frame write is needed if pixels are set in the bottom line,
 587          * or else grey lines rises up from the pixels
 588          */
 589         if (epd->pre_border_byte) {
 590                 unsigned int x;
 591
 592                 for (x = 0; x < (fb->width / 8); x++)
 593                         if (buf[x + (fb->width * (fb->height - 1) / 8)]) {
 594                                 repaper_frame_data_repeat(epd, buf,
 595                                                           epd->current_frame,
 596                                                           REPAPER_NORMAL);
 597                                 break;
 598                         }
 599         }
 600
 601 out_free:
 602         kfree(buf);
 603 out_exit:
 604         drm_dev_exit(idx);
 605
 606         return ret;
 607 }
 608
 609 static void power_off(struct repaper_epd *epd)
 610 {
 611         /* Turn off power and all signals */
 612         gpiod_set_value_cansleep(epd->reset, 0);
 613         gpiod_set_value_cansleep(epd->panel_on, 0);
 614         if (epd->border)
 615                 gpiod_set_value_cansleep(epd->border, 0);
 616
 617         /* Ensure SPI MOSI and CLOCK are Low before CS Low */
 618         repaper_spi_mosi_low(epd->spi);
 619
 620         /* Discharge pulse */
 621         gpiod_set_value_cansleep(epd->discharge, 1);
 622         msleep(150);
 623         gpiod_set_value_cansleep(epd->discharge, 0);
 624 }
 625
 626 static enum drm_mode_status repaper_pipe_mode_valid(struct drm_simple_display_pipe *pipe,
 627                                                     const struct drm_display_mode *mode)
 628 {
 629         struct drm_crtc *crtc = &pipe->crtc;
 630         struct repaper_epd *epd = drm_to_epd(crtc->dev);
 631
 632         return drm_crtc_helper_mode_valid_fixed(crtc, mode, epd->mode);
 633 }
 634
 635 static void repaper_pipe_enable(struct drm_simple_display_pipe *pipe,
 636                                 struct drm_crtc_state *crtc_state,
 637                                 struct drm_plane_state *plane_state)
 638 {
 639         struct repaper_epd *epd = drm_to_epd(pipe->crtc.dev);
 640         struct spi_device *spi = epd->spi;
 641         struct device *dev = &spi->dev;
 642         bool dc_ok = false;
 643         int i, ret, idx;
 644
 645         if (!drm_dev_enter(pipe->crtc.dev, &idx))
 646                 return;
 647
 648         DRM_DEBUG_DRIVER("\n");
 649
 650         /* Power up sequence */
 651         gpiod_set_value_cansleep(epd->reset, 0);
 652         gpiod_set_value_cansleep(epd->panel_on, 0);
 653         gpiod_set_value_cansleep(epd->discharge, 0);
 654         if (epd->border)
 655                 gpiod_set_value_cansleep(epd->border, 0);
 656         repaper_spi_mosi_low(spi);
 657         usleep_range(5000, 10000);
 658
 659         gpiod_set_value_cansleep(epd->panel_on, 1);
 660         /*
 661          * This delay comes from the repaper.org userspace driver, it's not
 662          * mentioned in the datasheet.
 663          */
 664         usleep_range(10000, 15000);
 665         gpiod_set_value_cansleep(epd->reset, 1);
 666         if (epd->border)
 667                 gpiod_set_value_cansleep(epd->border, 1);
 668         usleep_range(5000, 10000);
 669         gpiod_set_value_cansleep(epd->reset, 0);
 670         usleep_range(5000, 10000);
 671         gpiod_set_value_cansleep(epd->reset, 1);
 672         usleep_range(5000, 10000);
 673
 674         /* Wait for COG to become ready */
 675         for (i = 100; i > 0; i--) {
 676                 if (!gpiod_get_value_cansleep(epd->busy))
 677                         break;
 678
 679                 usleep_range(10, 100);
 680         }
 681
 682         if (!i) {
 683                 DRM_DEV_ERROR(dev, "timeout waiting for panel to become ready.\n");
 684                 power_off(epd);
 685                 goto out_exit;
 686         }
 687
 688         repaper_read_id(spi);
 689         ret = repaper_read_id(spi);
 690         if (ret != REPAPER_RID_G2_COG_ID) {
 691                 if (ret < 0)
 692                         dev_err(dev, "failed to read chip (%d)\n", ret);
 693                 else
 694                         dev_err(dev, "wrong COG ID 0x%02x\n", ret);
 695                 power_off(epd);
 696                 goto out_exit;
 697         }
 698
 699         /* Disable OE */
 700         repaper_write_val(spi, 0x02, 0x40);
 701
 702         ret = repaper_read_val(spi, 0x0f);
 703         if (ret < 0 || !(ret & 0x80)) {
 704                 if (ret < 0)
 705                         DRM_DEV_ERROR(dev, "failed to read chip (%d)\n", ret);
 706                 else
 707                         DRM_DEV_ERROR(dev, "panel is reported broken\n");
 708                 power_off(epd);
 709                 goto out_exit;
 710         }
 711
 712         /* Power saving mode */
 713         repaper_write_val(spi, 0x0b, 0x02);
 714         /* Channel select */
 715         repaper_write_buf(spi, 0x01, epd->channel_select, 8);
 716         /* High power mode osc */
 717         repaper_write_val(spi, 0x07, 0xd1);
 718         /* Power setting */
 719         repaper_write_val(spi, 0x08, 0x02);
 720         /* Vcom level */
 721         repaper_write_val(spi, 0x09, 0xc2);
 722         /* Power setting */
 723         repaper_write_val(spi, 0x04, 0x03);
 724         /* Driver latch on */
 725         repaper_write_val(spi, 0x03, 0x01);
 726         /* Driver latch off */
 727         repaper_write_val(spi, 0x03, 0x00);
 728         usleep_range(5000, 10000);
 729
 730         /* Start chargepump */
 731         for (i = 0; i < 4; ++i) {
 732                 /* Charge pump positive voltage on - VGH/VDL on */
 733                 repaper_write_val(spi, 0x05, 0x01);
 734                 msleep(240);
 735
 736                 /* Charge pump negative voltage on - VGL/VDL on */
 737                 repaper_write_val(spi, 0x05, 0x03);
 738                 msleep(40);
 739
 740                 /* Charge pump Vcom on - Vcom driver on */
 741                 repaper_write_val(spi, 0x05, 0x0f);
 742                 msleep(40);
 743
 744                 /* check DC/DC */
 745                 ret = repaper_read_val(spi, 0x0f);
 746                 if (ret < 0) {
 747                         DRM_DEV_ERROR(dev, "failed to read chip (%d)\n", ret);
 748                         power_off(epd);
 749                         goto out_exit;
 750                 }
 751
 752                 if (ret & 0x40) {
 753                         dc_ok = true;
 754                         break;
 755                 }
 756         }
 757
 758         if (!dc_ok) {
 759                 DRM_DEV_ERROR(dev, "dc/dc failed\n");
 760                 power_off(epd);
 761                 goto out_exit;
 762         }
 763
 764         /*
 765          * Output enable to disable
 766          * The userspace driver sets this to 0x04, but the datasheet says 0x06
 767          */
 768         repaper_write_val(spi, 0x02, 0x04);
 769
 770         epd->partial = false;
 771 out_exit:
 772         drm_dev_exit(idx);
 773 }
 774
 775 static void repaper_pipe_disable(struct drm_simple_display_pipe *pipe)
 776 {
 777         struct repaper_epd *epd = drm_to_epd(pipe->crtc.dev);
 778         struct spi_device *spi = epd->spi;
 779         unsigned int line;
 780
 781         /*
 782          * This callback is not protected by drm_dev_enter/exit since we want to
 783          * turn off the display on regular driver unload. It's highly unlikely
 784          * that the underlying SPI controller is gone should this be called after
 785          * unplug.
 786          */
 787
 788         DRM_DEBUG_DRIVER("\n");
 789
 790         /* Nothing frame */
 791         for (line = 0; line < epd->height; line++)
 792                 repaper_one_line(epd, 0x7fffu, NULL, 0x00, NULL,
 793                                  REPAPER_COMPENSATE);
 794
 795         /* 2.7" */
 796         if (epd->border) {
 797                 /* Dummy line */
 798                 repaper_one_line(epd, 0x7fffu, NULL, 0x00, NULL,
 799                                  REPAPER_COMPENSATE);
 800                 msleep(25);
 801                 gpiod_set_value_cansleep(epd->border, 0);
 802                 msleep(200);
 803                 gpiod_set_value_cansleep(epd->border, 1);
 804         } else {
 805                 /* Border dummy line */
 806                 repaper_one_line(epd, 0x7fffu, NULL, 0x00, NULL,
 807                                  REPAPER_NORMAL);
 808                 msleep(200);
 809         }
 810
 811         /* not described in datasheet */
 812         repaper_write_val(spi, 0x0b, 0x00);
 813         /* Latch reset turn on */
 814         repaper_write_val(spi, 0x03, 0x01);
 815         /* Power off charge pump Vcom */
 816         repaper_write_val(spi, 0x05, 0x03);
 817         /* Power off charge pump neg voltage */
 818         repaper_write_val(spi, 0x05, 0x01);
 819         msleep(120);
 820         /* Discharge internal */
 821         repaper_write_val(spi, 0x04, 0x80);
 822         /* turn off all charge pumps */
 823         repaper_write_val(spi, 0x05, 0x00);
 824         /* Turn off osc */
 825         repaper_write_val(spi, 0x07, 0x01);
 826         msleep(50);
 827
 828         power_off(epd);
 829 }
 830
 831 static void repaper_pipe_update(struct drm_simple_display_pipe *pipe,
 832                                 struct drm_plane_state *old_state)
 833 {
 834         struct drm_plane_state *state = pipe->plane.state;
 835         struct drm_format_conv_state fmtcnv_state = DRM_FORMAT_CONV_STATE_INIT;
 836         struct drm_rect rect;
 837
 838         if (!pipe->crtc.state->active)
 839                 return;
 840
 841         if (drm_atomic_helper_damage_merged(old_state, state, &rect))
 842                 repaper_fb_dirty(state->fb, &fmtcnv_state);
 843
 844         drm_format_conv_state_release(&fmtcnv_state);
 845 }
 846
 847 static const struct drm_simple_display_pipe_funcs repaper_pipe_funcs = {
 848         .mode_valid = repaper_pipe_mode_valid,
 849         .enable = repaper_pipe_enable,
 850         .disable = repaper_pipe_disable,
 851         .update = repaper_pipe_update,
 852 };
 853
 854 static int repaper_connector_get_modes(struct drm_connector *connector)
 855 {
 856         struct repaper_epd *epd = drm_to_epd(connector->dev);
 857
 858         return drm_connector_helper_get_modes_fixed(connector, epd->mode);
 859 }
 860
 861 static const struct drm_connector_helper_funcs repaper_connector_hfuncs = {
 862         .get_modes = repaper_connector_get_modes,
 863 };
 864
 865 static const struct drm_connector_funcs repaper_connector_funcs = {
 866         .reset = drm_atomic_helper_connector_reset,
 867         .fill_modes = drm_helper_probe_single_connector_modes,
 868         .destroy = drm_connector_cleanup,
 869         .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
 870         .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
 871 };
 872
 873 static const struct drm_mode_config_funcs repaper_mode_config_funcs = {
 874         .fb_create = drm_gem_fb_create_with_dirty,
 875         .atomic_check = drm_atomic_helper_check,
 876         .atomic_commit = drm_atomic_helper_commit,
 877 };
 878
 879 static const uint32_t repaper_formats[] = {
 880         DRM_FORMAT_XRGB8888,
 881 };
 882
 883 static const struct drm_display_mode repaper_e1144cs021_mode = {
 884         DRM_SIMPLE_MODE(128, 96, 29, 22),
 885 };
 886
 887 static const u8 repaper_e1144cs021_cs[] = { 0x00, 0x00, 0x00, 0x00,
 888                                             0x00, 0x0f, 0xff, 0x00 };
 889
 890 static const struct drm_display_mode repaper_e1190cs021_mode = {
 891         DRM_SIMPLE_MODE(144, 128, 36, 32),
 892 };
 893
 894 static const u8 repaper_e1190cs021_cs[] = { 0x00, 0x00, 0x00, 0x03,
 895                                             0xfc, 0x00, 0x00, 0xff };
 896
 897 static const struct drm_display_mode repaper_e2200cs021_mode = {
 898         DRM_SIMPLE_MODE(200, 96, 46, 22),
 899 };
 900
 901 static const u8 repaper_e2200cs021_cs[] = { 0x00, 0x00, 0x00, 0x00,
 902                                             0x01, 0xff, 0xe0, 0x00 };
 903
 904 static const struct drm_display_mode repaper_e2271cs021_mode = {
 905         DRM_SIMPLE_MODE(264, 176, 57, 38),
 906 };
 907
 908 static const u8 repaper_e2271cs021_cs[] = { 0x00, 0x00, 0x00, 0x7f,
 909                                             0xff, 0xfe, 0x00, 0x00 };
 910
 911 DEFINE_DRM_GEM_DMA_FOPS(repaper_fops);
 912
 913 static const struct drm_driver repaper_driver = {
 914         .driver_features        = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
 915         .fops                   = &repaper_fops,
 916         DRM_GEM_DMA_DRIVER_OPS_VMAP,
 917         DRM_FBDEV_DMA_DRIVER_OPS,
 918         .name                   = "repaper",
 919         .desc                   = "Pervasive Displays RePaper e-ink panels",
 920         .major                  = 1,
 921         .minor                  = 0,
 922 };
 923
 924 static const struct of_device_id repaper_of_match[] = {
 925         { .compatible = "pervasive,e1144cs021", .data = (void *)E1144CS021 },
 926         { .compatible = "pervasive,e1190cs021", .data = (void *)E1190CS021 },
 927         { .compatible = "pervasive,e2200cs021", .data = (void *)E2200CS021 },
 928         { .compatible = "pervasive,e2271cs021", .data = (void *)E2271CS021 },
 929         {},
 930 };
 931 MODULE_DEVICE_TABLE(of, repaper_of_match);
 932
 933 static const struct spi_device_id repaper_id[] = {
 934         { "e1144cs021", E1144CS021 },
 935         { "e1190cs021", E1190CS021 },
 936         { "e2200cs021", E2200CS021 },
 937         { "e2271cs021", E2271CS021 },
 938         { },
 939 };
 940 MODULE_DEVICE_TABLE(spi, repaper_id);
 941
 942 static int repaper_probe(struct spi_device *spi)
 943 {
 944         const struct drm_display_mode *mode;
 945         const struct spi_device_id *spi_id;
 946         struct device *dev = &spi->dev;
 947         enum repaper_model model;
 948         const char *thermal_zone;
 949         struct repaper_epd *epd;
 950         size_t line_buffer_size;
 951         struct drm_device *drm;
 952         const void *match;
 953         int ret;
 954
 955         match = device_get_match_data(dev);
 956         if (match) {
 957                 model = (enum repaper_model)(uintptr_t)match;
 958         } else {
 959                 spi_id = spi_get_device_id(spi);
 960                 model = (enum repaper_model)spi_id->driver_data;
 961         }
 962
 963         /* The SPI device is used to allocate dma memory */
 964         if (!dev->coherent_dma_mask) {
 965                 ret = dma_coerce_mask_and_coherent(dev, DMA_BIT_MASK(32));
 966                 if (ret) {
 967                         dev_warn(dev, "Failed to set dma mask %d\n", ret);
 968                         return ret;
 969                 }
 970         }
 971
 972         epd = devm_drm_dev_alloc(dev, &repaper_driver,
 973                                  struct repaper_epd, drm);
 974         if (IS_ERR(epd))
 975                 return PTR_ERR(epd);
 976
 977         drm = &epd->drm;
 978
 979         ret = drmm_mode_config_init(drm);
 980         if (ret)
 981                 return ret;
 982         drm->mode_config.funcs = &repaper_mode_config_funcs;
 983
 984         epd->spi = spi;
 985
 986         epd->panel_on = devm_gpiod_get(dev, "panel-on", GPIOD_OUT_LOW);
 987         if (IS_ERR(epd->panel_on)) {
 988                 ret = PTR_ERR(epd->panel_on);
 989                 if (ret != -EPROBE_DEFER)
 990                         DRM_DEV_ERROR(dev, "Failed to get gpio 'panel-on'\n");
 991                 return ret;
 992         }
 993
 994         epd->discharge = devm_gpiod_get(dev, "discharge", GPIOD_OUT_LOW);
 995         if (IS_ERR(epd->discharge)) {
 996                 ret = PTR_ERR(epd->discharge);
 997                 if (ret != -EPROBE_DEFER)
 998                         DRM_DEV_ERROR(dev, "Failed to get gpio 'discharge'\n");
 999                 return ret;
1000         }
1001
1002         epd->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
1003         if (IS_ERR(epd->reset)) {
1004                 ret = PTR_ERR(epd->reset);
1005                 if (ret != -EPROBE_DEFER)
1006                         DRM_DEV_ERROR(dev, "Failed to get gpio 'reset'\n");
1007                 return ret;
1008         }
1009
1010         epd->busy = devm_gpiod_get(dev, "busy", GPIOD_IN);
1011         if (IS_ERR(epd->busy)) {
1012                 ret = PTR_ERR(epd->busy);
1013                 if (ret != -EPROBE_DEFER)
1014                         DRM_DEV_ERROR(dev, "Failed to get gpio 'busy'\n");
1015                 return ret;
1016         }
1017
1018         if (!device_property_read_string(dev, "pervasive,thermal-zone",
1019                                          &thermal_zone)) {
1020                 epd->thermal = thermal_zone_get_zone_by_name(thermal_zone);
1021                 if (IS_ERR(epd->thermal)) {
1022                         DRM_DEV_ERROR(dev, "Failed to get thermal zone: %s\n", thermal_zone);
1023                         return PTR_ERR(epd->thermal);
1024                 }
1025         }
1026
1027         switch (model) {
1028         case E1144CS021:
1029                 mode = &repaper_e1144cs021_mode;
1030                 epd->channel_select = repaper_e1144cs021_cs;
1031                 epd->stage_time = 480;
1032                 epd->bytes_per_scan = 96 / 4;
1033                 epd->middle_scan = true; /* data-scan-data */
1034                 epd->pre_border_byte = false;
1035                 epd->border_byte = REPAPER_BORDER_BYTE_ZERO;
1036                 break;
1037
1038         case E1190CS021:
1039                 mode = &repaper_e1190cs021_mode;
1040                 epd->channel_select = repaper_e1190cs021_cs;
1041                 epd->stage_time = 480;
1042                 epd->bytes_per_scan = 128 / 4 / 2;
1043                 epd->middle_scan = false; /* scan-data-scan */
1044                 epd->pre_border_byte = false;
1045                 epd->border_byte = REPAPER_BORDER_BYTE_SET;
1046                 break;
1047
1048         case E2200CS021:
1049                 mode = &repaper_e2200cs021_mode;
1050                 epd->channel_select = repaper_e2200cs021_cs;
1051                 epd->stage_time = 480;
1052                 epd->bytes_per_scan = 96 / 4;
1053                 epd->middle_scan = true; /* data-scan-data */
1054                 epd->pre_border_byte = true;
1055                 epd->border_byte = REPAPER_BORDER_BYTE_NONE;
1056                 break;
1057
1058         case E2271CS021:
1059                 epd->border = devm_gpiod_get(dev, "border", GPIOD_OUT_LOW);
1060                 if (IS_ERR(epd->border)) {
1061                         ret = PTR_ERR(epd->border);
1062                         if (ret != -EPROBE_DEFER)
1063                                 DRM_DEV_ERROR(dev, "Failed to get gpio 'border'\n");
1064                         return ret;
1065                 }
1066
1067                 mode = &repaper_e2271cs021_mode;
1068                 epd->channel_select = repaper_e2271cs021_cs;
1069                 epd->stage_time = 630;
1070                 epd->bytes_per_scan = 176 / 4;
1071                 epd->middle_scan = true; /* data-scan-data */
1072                 epd->pre_border_byte = true;
1073                 epd->border_byte = REPAPER_BORDER_BYTE_NONE;
1074                 break;
1075
1076         default:
1077                 return -ENODEV;
1078         }
1079
1080         epd->mode = mode;
1081         epd->width = mode->hdisplay;
1082         epd->height = mode->vdisplay;
1083         epd->factored_stage_time = epd->stage_time;
1084
1085         line_buffer_size = 2 * epd->width / 8 + epd->bytes_per_scan + 2;
1086         epd->line_buffer = devm_kzalloc(dev, line_buffer_size, GFP_KERNEL);
1087         if (!epd->line_buffer)
1088                 return -ENOMEM;
1089
1090         epd->current_frame = devm_kzalloc(dev, epd->width * epd->height / 8,
1091                                           GFP_KERNEL);
1092         if (!epd->current_frame)
1093                 return -ENOMEM;
1094
1095         drm->mode_config.min_width = mode->hdisplay;
1096         drm->mode_config.max_width = mode->hdisplay;
1097         drm->mode_config.min_height = mode->vdisplay;
1098         drm->mode_config.max_height = mode->vdisplay;
1099
1100         drm_connector_helper_add(&epd->connector, &repaper_connector_hfuncs);
1101         ret = drm_connector_init(drm, &epd->connector, &repaper_connector_funcs,
1102                                  DRM_MODE_CONNECTOR_SPI);
1103         if (ret)
1104                 return ret;
1105
1106         ret = drm_simple_display_pipe_init(drm, &epd->pipe, &repaper_pipe_funcs,
1107                                            repaper_formats, ARRAY_SIZE(repaper_formats),
1108                                            NULL, &epd->connector);
1109         if (ret)
1110                 return ret;
1111
1112         drm_mode_config_reset(drm);
1113
1114         ret = drm_dev_register(drm, 0);
1115         if (ret)
1116                 return ret;
1117
1118         spi_set_drvdata(spi, drm);
1119
1120         DRM_DEBUG_DRIVER("SPI speed: %uMHz\n", spi->max_speed_hz / 1000000);
1121
1122         drm_client_setup(drm, NULL);
1123
1124         return 0;
1125 }
1126
1127 static void repaper_remove(struct spi_device *spi)
1128 {
1129         struct drm_device *drm = spi_get_drvdata(spi);
1130
1131         drm_dev_unplug(drm);
1132         drm_atomic_helper_shutdown(drm);
1133 }
1134
1135 static void repaper_shutdown(struct spi_device *spi)
1136 {
1137         drm_atomic_helper_shutdown(spi_get_drvdata(spi));
1138 }
1139
1140 static struct spi_driver repaper_spi_driver = {
1141         .driver = {
1142                 .name = "repaper",
1143                 .of_match_table = repaper_of_match,
1144         },
1145         .id_table = repaper_id,
1146         .probe = repaper_probe,
1147         .remove = repaper_remove,
1148         .shutdown = repaper_shutdown,
1149 };
1150 module_spi_driver(repaper_spi_driver);
1151
1152 MODULE_DESCRIPTION("Pervasive Displays RePaper DRM driver");
1153 MODULE_AUTHOR("Noralf Trønnes");
1154 MODULE_LICENSE("GPL");