drivers/gpu/drm/tiny/sharp-memory.c

   1 // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
   2
   3 #include <drm/drm_atomic.h>
   4 #include <drm/drm_atomic_helper.h>
   5 #include <drm/drm_client_setup.h>
   6 #include <drm/drm_connector.h>
   7 #include <drm/drm_damage_helper.h>
   8 #include <drm/drm_drv.h>
   9 #include <drm/drm_fb_dma_helper.h>
  10 #include <drm/drm_fbdev_dma.h>
  11 #include <drm/drm_format_helper.h>
  12 #include <drm/drm_framebuffer.h>
  13 #include <drm/drm_gem_atomic_helper.h>
  14 #include <drm/drm_gem_dma_helper.h>
  15 #include <drm/drm_gem_framebuffer_helper.h>
  16 #include <drm/drm_managed.h>
  17 #include <drm/drm_modes.h>
  18 #include <drm/drm_probe_helper.h>
  19 #include <drm/drm_rect.h>
  20 #include <linux/bitrev.h>
  21 #include <linux/delay.h>
  22 #include <linux/gpio/consumer.h>
  23 #include <linux/kthread.h>
  24 #include <linux/mod_devicetable.h>
  25 #include <linux/module.h>
  26 #include <linux/mutex.h>
  27 #include <linux/pwm.h>
  28 #include <linux/spi/spi.h>
  29
  30 #define SHARP_MODE_PERIOD 8
  31 #define SHARP_ADDR_PERIOD 8
  32 #define SHARP_DUMMY_PERIOD 8
  33
  34 #define SHARP_MEMORY_DISPLAY_MAINTAIN_MODE 0
  35 #define SHARP_MEMORY_DISPLAY_UPDATE_MODE 1
  36 #define SHARP_MEMORY_DISPLAY_CLEAR_MODE 4
  37
  38 enum sharp_memory_model {
  39         LS010B7DH04,
  40         LS011B7DH03,
  41         LS012B7DD01,
  42         LS013B7DH03,
  43         LS013B7DH05,
  44         LS018B7DH02,
  45         LS027B7DH01,
  46         LS027B7DH01A,
  47         LS032B7DD02,
  48         LS044Q7DH01,
  49 };
  50
  51 enum sharp_memory_vcom_mode {
  52         SHARP_MEMORY_SOFTWARE_VCOM,
  53         SHARP_MEMORY_EXTERNAL_VCOM,
  54         SHARP_MEMORY_PWM_VCOM
  55 };
  56
  57 struct sharp_memory_device {
  58         struct drm_device drm;
  59         struct spi_device *spi;
  60
  61         const struct drm_display_mode *mode;
  62
  63         struct drm_crtc crtc;
  64         struct drm_plane plane;
  65         struct drm_encoder encoder;
  66         struct drm_connector connector;
  67
  68         struct gpio_desc *enable_gpio;
  69
  70         struct task_struct *sw_vcom_signal;
  71         struct pwm_device *pwm_vcom_signal;
  72
  73         enum sharp_memory_vcom_mode vcom_mode;
  74         u8 vcom;
  75
  76         u32 pitch;
  77         u32 tx_buffer_size;
  78         u8 *tx_buffer;
  79
  80         /* When vcom_mode == "software" a kthread is used to periodically send a
  81          * 'maintain display' message over spi. This mutex ensures tx_buffer access
  82          * and spi bus usage is synchronized in this case.
  83          */
  84         struct mutex tx_mutex;
  85 };
  86
  87 static inline int sharp_memory_spi_write(struct spi_device *spi, void *buf, size_t len)
  88 {
  89         /* Reverse the bit order */
  90         for (u8 *b = buf; b < ((u8 *)buf) + len; ++b)
  91                 *b = bitrev8(*b);
  92
  93         return spi_write(spi, buf, len);
  94 }
  95
  96 static inline struct sharp_memory_device *drm_to_sharp_memory_device(struct drm_device *drm)
  97 {
  98         return container_of(drm, struct sharp_memory_device, drm);
  99 }
 100
 101 DEFINE_DRM_GEM_DMA_FOPS(sharp_memory_fops);
 102
 103 static const struct drm_driver sharp_memory_drm_driver = {
 104         .driver_features        = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
 105         .fops                   = &sharp_memory_fops,
 106         DRM_GEM_DMA_DRIVER_OPS_VMAP,
 107         DRM_FBDEV_DMA_DRIVER_OPS,
 108         .name                   = "sharp_memory_display",
 109         .desc                   = "Sharp Display Memory LCD",
 110         .date                   = "20231129",
 111         .major                  = 1,
 112         .minor                  = 0,
 113 };
 114
 115 static inline void sharp_memory_set_tx_buffer_mode(u8 *buffer, u8 mode, u8 vcom)
 116 {
 117         *buffer = mode | (vcom << 1);
 118 }
 119
 120 static inline void sharp_memory_set_tx_buffer_addresses(u8 *buffer,
 121                                                         struct drm_rect clip,
 122                                                         u32 pitch)
 123 {
 124         for (u32 line = 0; line < clip.y2; ++line)
 125                 buffer[line * pitch] = line + 1;
 126 }
 127
 128 static void sharp_memory_set_tx_buffer_data(u8 *buffer,
 129                                             struct drm_framebuffer *fb,
 130                                             struct drm_rect clip,
 131                                             u32 pitch,
 132                                             struct drm_format_conv_state *fmtcnv_state)
 133 {
 134         int ret;
 135         struct iosys_map dst, vmap;
 136         struct drm_gem_dma_object *dma_obj = drm_fb_dma_get_gem_obj(fb, 0);
 137
 138         ret = drm_gem_fb_begin_cpu_access(fb, DMA_FROM_DEVICE);
 139         if (ret)
 140                 return;
 141
 142         iosys_map_set_vaddr(&dst, buffer);
 143         iosys_map_set_vaddr(&vmap, dma_obj->vaddr);
 144
 145         drm_fb_xrgb8888_to_mono(&dst, &pitch, &vmap, fb, &clip, fmtcnv_state);
 146
 147         drm_gem_fb_end_cpu_access(fb, DMA_FROM_DEVICE);
 148 }
 149
 150 static int sharp_memory_update_display(struct sharp_memory_device *smd,
 151                                        struct drm_framebuffer *fb,
 152                                        struct drm_rect clip,
 153                                        struct drm_format_conv_state *fmtcnv_state)
 154 {
 155         int ret;
 156         u32 pitch = smd->pitch;
 157         u8 vcom = smd->vcom;
 158         u8 *tx_buffer = smd->tx_buffer;
 159         u32 tx_buffer_size = smd->tx_buffer_size;
 160
 161         mutex_lock(&smd->tx_mutex);
 162
 163         /* Populate the transmit buffer with frame data */
 164         sharp_memory_set_tx_buffer_mode(&tx_buffer[0],
 165                                         SHARP_MEMORY_DISPLAY_UPDATE_MODE, vcom);
 166         sharp_memory_set_tx_buffer_addresses(&tx_buffer[1], clip, pitch);
 167         sharp_memory_set_tx_buffer_data(&tx_buffer[2], fb, clip, pitch, fmtcnv_state);
 168
 169         ret = sharp_memory_spi_write(smd->spi, tx_buffer, tx_buffer_size);
 170
 171         mutex_unlock(&smd->tx_mutex);
 172
 173         return ret;
 174 }
 175
 176 static int sharp_memory_maintain_display(struct sharp_memory_device *smd)
 177 {
 178         int ret;
 179         u8 vcom = smd->vcom;
 180         u8 *tx_buffer = smd->tx_buffer;
 181
 182         mutex_lock(&smd->tx_mutex);
 183
 184         sharp_memory_set_tx_buffer_mode(&tx_buffer[0], SHARP_MEMORY_DISPLAY_MAINTAIN_MODE, vcom);
 185         tx_buffer[1] = 0; /* Write dummy data */
 186         ret = sharp_memory_spi_write(smd->spi, tx_buffer, 2);
 187
 188         mutex_unlock(&smd->tx_mutex);
 189
 190         return ret;
 191 }
 192
 193 static int sharp_memory_clear_display(struct sharp_memory_device *smd)
 194 {
 195         int ret;
 196         u8 vcom = smd->vcom;
 197         u8 *tx_buffer = smd->tx_buffer;
 198
 199         mutex_lock(&smd->tx_mutex);
 200
 201         sharp_memory_set_tx_buffer_mode(&tx_buffer[0], SHARP_MEMORY_DISPLAY_CLEAR_MODE, vcom);
 202         tx_buffer[1] = 0; /* write dummy data */
 203         ret = sharp_memory_spi_write(smd->spi, tx_buffer, 2);
 204
 205         mutex_unlock(&smd->tx_mutex);
 206
 207         return ret;
 208 }
 209
 210 static void sharp_memory_fb_dirty(struct drm_framebuffer *fb, struct drm_rect *rect,
 211                                   struct drm_format_conv_state *fmtconv_state)
 212 {
 213         struct drm_rect clip;
 214         struct sharp_memory_device *smd = drm_to_sharp_memory_device(fb->dev);
 215
 216         /* Always update a full line regardless of what is dirty */
 217         clip.x1 = 0;
 218         clip.x2 = fb->width;
 219         clip.y1 = rect->y1;
 220         clip.y2 = rect->y2;
 221
 222         sharp_memory_update_display(smd, fb, clip, fmtconv_state);
 223 }
 224
 225 static int sharp_memory_plane_atomic_check(struct drm_plane *plane,
 226                                            struct drm_atomic_state *state)
 227 {
 228         struct drm_plane_state *plane_state = drm_atomic_get_new_plane_state(state, plane);
 229         struct sharp_memory_device *smd;
 230         struct drm_crtc_state *crtc_state;
 231
 232         smd = container_of(plane, struct sharp_memory_device, plane);
 233         crtc_state = drm_atomic_get_new_crtc_state(state, &smd->crtc);
 234
 235         return drm_atomic_helper_check_plane_state(plane_state, crtc_state,
 236                                                    DRM_PLANE_NO_SCALING,
 237                                                    DRM_PLANE_NO_SCALING,
 238                                                    false, false);
 239 }
 240
 241 static void sharp_memory_plane_atomic_update(struct drm_plane *plane,
 242                                              struct drm_atomic_state *state)
 243 {
 244         struct drm_plane_state *old_state = drm_atomic_get_old_plane_state(state, plane);
 245         struct drm_plane_state *plane_state = plane->state;
 246         struct drm_format_conv_state fmtcnv_state = DRM_FORMAT_CONV_STATE_INIT;
 247         struct sharp_memory_device *smd;
 248         struct drm_rect rect;
 249
 250         smd = container_of(plane, struct sharp_memory_device, plane);
 251         if (!smd->crtc.state->active)
 252                 return;
 253
 254         if (drm_atomic_helper_damage_merged(old_state, plane_state, &rect))
 255                 sharp_memory_fb_dirty(plane_state->fb, &rect, &fmtcnv_state);
 256
 257         drm_format_conv_state_release(&fmtcnv_state);
 258 }
 259
 260 static const struct drm_plane_helper_funcs sharp_memory_plane_helper_funcs = {
 261         .prepare_fb = drm_gem_plane_helper_prepare_fb,
 262         .atomic_check = sharp_memory_plane_atomic_check,
 263         .atomic_update = sharp_memory_plane_atomic_update,
 264 };
 265
 266 static bool sharp_memory_format_mod_supported(struct drm_plane *plane,
 267                                               u32 format,
 268                                               u64 modifier)
 269 {
 270         return modifier == DRM_FORMAT_MOD_LINEAR;
 271 }
 272
 273 static const struct drm_plane_funcs sharp_memory_plane_funcs = {
 274         .update_plane = drm_atomic_helper_update_plane,
 275         .disable_plane = drm_atomic_helper_disable_plane,
 276         .destroy = drm_plane_cleanup,
 277         .reset = drm_atomic_helper_plane_reset,
 278         .atomic_duplicate_state = drm_atomic_helper_plane_duplicate_state,
 279         .atomic_destroy_state = drm_atomic_helper_plane_destroy_state,
 280         .format_mod_supported = sharp_memory_format_mod_supported,
 281 };
 282
 283 static enum drm_mode_status sharp_memory_crtc_mode_valid(struct drm_crtc *crtc,
 284                                                          const struct drm_display_mode *mode)
 285 {
 286         struct sharp_memory_device *smd = drm_to_sharp_memory_device(crtc->dev);
 287
 288         return drm_crtc_helper_mode_valid_fixed(crtc, mode, smd->mode);
 289 }
 290
 291 static int sharp_memory_crtc_check(struct drm_crtc *crtc,
 292                                    struct drm_atomic_state *state)
 293 {
 294         struct drm_crtc_state *crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
 295         int ret;
 296
 297         if (!crtc_state->enable)
 298                 goto out;
 299
 300         ret = drm_atomic_helper_check_crtc_primary_plane(crtc_state);
 301         if (ret)
 302                 return ret;
 303
 304 out:
 305         return drm_atomic_add_affected_planes(state, crtc);
 306 }
 307
 308 static int sharp_memory_sw_vcom_signal_thread(void *data)
 309 {
 310         struct sharp_memory_device *smd = data;
 311
 312         while (!kthread_should_stop()) {
 313                 smd->vcom ^= 1; /* Toggle vcom */
 314                 sharp_memory_maintain_display(smd);
 315                 msleep(1000);
 316         }
 317
 318         return 0;
 319 }
 320
 321 static void sharp_memory_crtc_enable(struct drm_crtc *crtc,
 322                                      struct drm_atomic_state *state)
 323 {
 324         struct sharp_memory_device *smd = drm_to_sharp_memory_device(crtc->dev);
 325
 326         sharp_memory_clear_display(smd);
 327
 328         if (smd->enable_gpio)
 329                 gpiod_set_value(smd->enable_gpio, 1);
 330 }
 331
 332 static void sharp_memory_crtc_disable(struct drm_crtc *crtc,
 333                                       struct drm_atomic_state *state)
 334 {
 335         struct sharp_memory_device *smd = drm_to_sharp_memory_device(crtc->dev);
 336
 337         sharp_memory_clear_display(smd);
 338
 339         if (smd->enable_gpio)
 340                 gpiod_set_value(smd->enable_gpio, 0);
 341 }
 342
 343 static const struct drm_crtc_helper_funcs sharp_memory_crtc_helper_funcs = {
 344         .mode_valid = sharp_memory_crtc_mode_valid,
 345         .atomic_check = sharp_memory_crtc_check,
 346         .atomic_enable = sharp_memory_crtc_enable,
 347         .atomic_disable = sharp_memory_crtc_disable,
 348 };
 349
 350 static const struct drm_crtc_funcs sharp_memory_crtc_funcs = {
 351         .reset = drm_atomic_helper_crtc_reset,
 352         .destroy = drm_crtc_cleanup,
 353         .set_config = drm_atomic_helper_set_config,
 354         .page_flip = drm_atomic_helper_page_flip,
 355         .atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
 356         .atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
 357 };
 358
 359 static const struct drm_encoder_funcs sharp_memory_encoder_funcs = {
 360         .destroy = drm_encoder_cleanup,
 361 };
 362
 363 static int sharp_memory_connector_get_modes(struct drm_connector *connector)
 364 {
 365         struct sharp_memory_device *smd = drm_to_sharp_memory_device(connector->dev);
 366
 367         return drm_connector_helper_get_modes_fixed(connector, smd->mode);
 368 }
 369
 370 static const struct drm_connector_helper_funcs sharp_memory_connector_hfuncs = {
 371         .get_modes = sharp_memory_connector_get_modes,
 372 };
 373
 374 static const struct drm_connector_funcs sharp_memory_connector_funcs = {
 375         .reset = drm_atomic_helper_connector_reset,
 376         .fill_modes = drm_helper_probe_single_connector_modes,
 377         .destroy = drm_connector_cleanup,
 378         .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
 379         .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
 380
 381 };
 382
 383 static const struct drm_mode_config_funcs sharp_memory_mode_config_funcs = {
 384         .fb_create = drm_gem_fb_create_with_dirty,
 385         .atomic_check = drm_atomic_helper_check,
 386         .atomic_commit = drm_atomic_helper_commit,
 387 };
 388
 389 static const struct drm_display_mode sharp_memory_ls010b7dh04_mode = {
 390         DRM_SIMPLE_MODE(128, 128, 18, 18),
 391 };
 392
 393 static const struct drm_display_mode sharp_memory_ls011b7dh03_mode = {
 394         DRM_SIMPLE_MODE(160, 68, 25, 10),
 395 };
 396
 397 static const struct drm_display_mode sharp_memory_ls012b7dd01_mode = {
 398         DRM_SIMPLE_MODE(184, 38, 29, 6),
 399 };
 400
 401 static const struct drm_display_mode sharp_memory_ls013b7dh03_mode = {
 402         DRM_SIMPLE_MODE(128, 128, 23, 23),
 403 };
 404
 405 static const struct drm_display_mode sharp_memory_ls013b7dh05_mode = {
 406         DRM_SIMPLE_MODE(144, 168, 20, 24),
 407 };
 408
 409 static const struct drm_display_mode sharp_memory_ls018b7dh02_mode = {
 410         DRM_SIMPLE_MODE(230, 303, 27, 36),
 411 };
 412
 413 static const struct drm_display_mode sharp_memory_ls027b7dh01_mode = {
 414         DRM_SIMPLE_MODE(400, 240, 58, 35),
 415 };
 416
 417 static const struct drm_display_mode sharp_memory_ls032b7dd02_mode = {
 418         DRM_SIMPLE_MODE(336, 536, 42, 68),
 419 };
 420
 421 static const struct drm_display_mode sharp_memory_ls044q7dh01_mode = {
 422         DRM_SIMPLE_MODE(320, 240, 89, 67),
 423 };
 424
 425 static const struct spi_device_id sharp_memory_ids[] = {
 426         {"ls010b7dh04", (kernel_ulong_t)&sharp_memory_ls010b7dh04_mode},
 427         {"ls011b7dh03", (kernel_ulong_t)&sharp_memory_ls011b7dh03_mode},
 428         {"ls012b7dd01", (kernel_ulong_t)&sharp_memory_ls012b7dd01_mode},
 429         {"ls013b7dh03", (kernel_ulong_t)&sharp_memory_ls013b7dh03_mode},
 430         {"ls013b7dh05", (kernel_ulong_t)&sharp_memory_ls013b7dh05_mode},
 431         {"ls018b7dh02", (kernel_ulong_t)&sharp_memory_ls018b7dh02_mode},
 432         {"ls027b7dh01", (kernel_ulong_t)&sharp_memory_ls027b7dh01_mode},
 433         {"ls027b7dh01a", (kernel_ulong_t)&sharp_memory_ls027b7dh01_mode},
 434         {"ls032b7dd02", (kernel_ulong_t)&sharp_memory_ls032b7dd02_mode},
 435         {"ls044q7dh01", (kernel_ulong_t)&sharp_memory_ls044q7dh01_mode},
 436         {},
 437 };
 438 MODULE_DEVICE_TABLE(spi, sharp_memory_ids);
 439
 440 static const struct of_device_id sharp_memory_of_match[] = {
 441         {.compatible = "sharp,ls010b7dh04", &sharp_memory_ls010b7dh04_mode},
 442         {.compatible = "sharp,ls011b7dh03", &sharp_memory_ls011b7dh03_mode},
 443         {.compatible = "sharp,ls012b7dd01", &sharp_memory_ls012b7dd01_mode},
 444         {.compatible = "sharp,ls013b7dh03", &sharp_memory_ls013b7dh03_mode},
 445         {.compatible = "sharp,ls013b7dh05", &sharp_memory_ls013b7dh05_mode},
 446         {.compatible = "sharp,ls018b7dh02", &sharp_memory_ls018b7dh02_mode},
 447         {.compatible = "sharp,ls027b7dh01", &sharp_memory_ls027b7dh01_mode},
 448         {.compatible = "sharp,ls027b7dh01a", &sharp_memory_ls027b7dh01_mode},
 449         {.compatible = "sharp,ls032b7dd02", &sharp_memory_ls032b7dd02_mode},
 450         {.compatible = "sharp,ls044q7dh01", &sharp_memory_ls044q7dh01_mode},
 451         {},
 452 };
 453 MODULE_DEVICE_TABLE(of, sharp_memory_of_match);
 454
 455 static const u32 sharp_memory_formats[] = {
 456         DRM_FORMAT_XRGB8888,
 457 };
 458
 459 static int sharp_memory_pipe_init(struct drm_device *dev,
 460                                   struct sharp_memory_device *smd,
 461                                   const u32 *formats, unsigned int format_count,
 462                                   const u64 *format_modifiers)
 463 {
 464         int ret;
 465         struct drm_encoder *encoder = &smd->encoder;
 466         struct drm_plane *plane = &smd->plane;
 467         struct drm_crtc *crtc = &smd->crtc;
 468         struct drm_connector *connector = &smd->connector;
 469
 470         drm_plane_helper_add(plane, &sharp_memory_plane_helper_funcs);
 471         ret = drm_universal_plane_init(dev, plane, 0,
 472                                        &sharp_memory_plane_funcs,
 473                                        formats, format_count,
 474                                        format_modifiers,
 475                                        DRM_PLANE_TYPE_PRIMARY, NULL);
 476         if (ret)
 477                 return ret;
 478
 479         drm_crtc_helper_add(crtc, &sharp_memory_crtc_helper_funcs);
 480         ret = drm_crtc_init_with_planes(dev, crtc, plane, NULL,
 481                                         &sharp_memory_crtc_funcs, NULL);
 482         if (ret)
 483                 return ret;
 484
 485         encoder->possible_crtcs = drm_crtc_mask(crtc);
 486         ret = drm_encoder_init(dev, encoder, &sharp_memory_encoder_funcs,
 487                                DRM_MODE_ENCODER_NONE, NULL);
 488         if (ret)
 489                 return ret;
 490
 491         ret = drm_connector_init(&smd->drm, &smd->connector,
 492                                  &sharp_memory_connector_funcs,
 493                                  DRM_MODE_CONNECTOR_SPI);
 494         if (ret)
 495                 return ret;
 496
 497         drm_connector_helper_add(&smd->connector,
 498                                  &sharp_memory_connector_hfuncs);
 499
 500         return drm_connector_attach_encoder(connector, encoder);
 501 }
 502
 503 static int sharp_memory_init_pwm_vcom_signal(struct sharp_memory_device *smd)
 504 {
 505         int ret;
 506         struct device *dev = &smd->spi->dev;
 507         struct pwm_state pwm_state;
 508
 509         smd->pwm_vcom_signal = devm_pwm_get(dev, NULL);
 510         if (IS_ERR(smd->pwm_vcom_signal))
 511                 return dev_err_probe(dev, PTR_ERR(smd->pwm_vcom_signal),
 512                                      "Could not get pwm device\n");
 513
 514         pwm_init_state(smd->pwm_vcom_signal, &pwm_state);
 515         pwm_set_relative_duty_cycle(&pwm_state, 1, 10);
 516         pwm_state.enabled = true;
 517         ret = pwm_apply_might_sleep(smd->pwm_vcom_signal, &pwm_state);
 518         if (ret)
 519                 return dev_err_probe(dev, -EINVAL, "Could not apply pwm state\n");
 520
 521         return 0;
 522 }
 523
 524 static int sharp_memory_probe(struct spi_device *spi)
 525 {
 526         int ret;
 527         struct device *dev;
 528         struct sharp_memory_device *smd;
 529         struct drm_device *drm;
 530         const char *vcom_mode_str;
 531
 532         dev = &spi->dev;
 533
 534         ret = spi_setup(spi);
 535         if (ret < 0)
 536                 return dev_err_probe(dev, ret, "Failed to setup spi device\n");
 537
 538         if (!dev->coherent_dma_mask) {
 539                 ret = dma_coerce_mask_and_coherent(dev, DMA_BIT_MASK(32));
 540                 if (ret)
 541                         return dev_err_probe(dev, ret, "Failed to set dma mask\n");
 542         }
 543
 544         smd = devm_drm_dev_alloc(dev, &sharp_memory_drm_driver,
 545                                  struct sharp_memory_device, drm);
 546         if (!smd)
 547                 return -ENOMEM;
 548
 549         spi_set_drvdata(spi, smd);
 550
 551         smd->spi = spi;
 552         drm = &smd->drm;
 553         ret = drmm_mode_config_init(drm);
 554         if (ret)
 555                 return dev_err_probe(dev, ret, "Failed to initialize drm config\n");
 556
 557         smd->enable_gpio = devm_gpiod_get_optional(dev, "enable", GPIOD_OUT_HIGH);
 558         if (!smd->enable_gpio)
 559                 dev_warn(dev, "Enable gpio not defined\n");
 560
 561         drm->mode_config.funcs = &sharp_memory_mode_config_funcs;
 562         smd->mode = spi_get_device_match_data(spi);
 563
 564         smd->pitch = (SHARP_ADDR_PERIOD + smd->mode->hdisplay + SHARP_DUMMY_PERIOD) / 8;
 565         smd->tx_buffer_size = (SHARP_MODE_PERIOD +
 566                                (SHARP_ADDR_PERIOD + (smd->mode->hdisplay) + SHARP_DUMMY_PERIOD) *
 567                                smd->mode->vdisplay) / 8;
 568
 569         smd->tx_buffer = devm_kzalloc(dev, smd->tx_buffer_size, GFP_KERNEL);
 570         if (!smd->tx_buffer)
 571                 return -ENOMEM;
 572
 573         mutex_init(&smd->tx_mutex);
 574
 575         /*
 576          * VCOM is a signal that prevents DC bias from being built up in
 577          * the panel resulting in pixels being forever stuck in one state.
 578          *
 579          * This driver supports three different methods to generate this
 580          * signal depending on EXTMODE pin:
 581          *
 582          * software (EXTMODE = L) - This mode uses a kthread to
 583          * periodically send a "maintain display" message to the display,
 584          * toggling the vcom bit on and off with each message
 585          *
 586          * external (EXTMODE = H) - This mode relies on an external
 587          * clock to generate the signal on the EXTCOMM pin
 588          *
 589          * pwm (EXTMODE = H) - This mode uses a pwm device to generate
 590          * the signal on the EXTCOMM pin
 591          *
 592          */
 593         if (device_property_read_string(dev, "sharp,vcom-mode", &vcom_mode_str))
 594                 return dev_err_probe(dev, -EINVAL,
 595                                      "Unable to find sharp,vcom-mode node in device tree\n");
 596
 597         if (!strcmp("software", vcom_mode_str)) {
 598                 smd->vcom_mode = SHARP_MEMORY_SOFTWARE_VCOM;
 599                 smd->sw_vcom_signal = kthread_run(sharp_memory_sw_vcom_signal_thread,
 600                                                   smd, "sw_vcom_signal");
 601
 602         } else if (!strcmp("external", vcom_mode_str)) {
 603                 smd->vcom_mode = SHARP_MEMORY_EXTERNAL_VCOM;
 604
 605         } else if (!strcmp("pwm", vcom_mode_str)) {
 606                 smd->vcom_mode = SHARP_MEMORY_PWM_VCOM;
 607                 ret = sharp_memory_init_pwm_vcom_signal(smd);
 608                 if (ret)
 609                         return ret;
 610         } else {
 611                 return dev_err_probe(dev, -EINVAL, "Invalid value set for vcom-mode\n");
 612         }
 613
 614         drm->mode_config.min_width = smd->mode->hdisplay;
 615         drm->mode_config.max_width = smd->mode->hdisplay;
 616         drm->mode_config.min_height = smd->mode->vdisplay;
 617         drm->mode_config.max_height = smd->mode->vdisplay;
 618
 619         ret = sharp_memory_pipe_init(drm, smd, sharp_memory_formats,
 620                                      ARRAY_SIZE(sharp_memory_formats),
 621                                      NULL);
 622         if (ret)
 623                 return dev_err_probe(dev, ret, "Failed to initialize display pipeline.\n");
 624
 625         drm_plane_enable_fb_damage_clips(&smd->plane);
 626         drm_mode_config_reset(drm);
 627
 628         ret = drm_dev_register(drm, 0);
 629         if (ret)
 630                 return dev_err_probe(dev, ret, "Failed to register drm device.\n");
 631
 632         drm_client_setup(drm, NULL);
 633
 634         return 0;
 635 }
 636
 637 static void sharp_memory_remove(struct spi_device *spi)
 638 {
 639         struct sharp_memory_device *smd = spi_get_drvdata(spi);
 640
 641         drm_dev_unplug(&smd->drm);
 642         drm_atomic_helper_shutdown(&smd->drm);
 643
 644         switch (smd->vcom_mode) {
 645         case SHARP_MEMORY_SOFTWARE_VCOM:
 646                 kthread_stop(smd->sw_vcom_signal);
 647                 break;
 648
 649         case SHARP_MEMORY_EXTERNAL_VCOM:
 650                 break;
 651
 652         case SHARP_MEMORY_PWM_VCOM:
 653                 pwm_disable(smd->pwm_vcom_signal);
 654                 break;
 655         }
 656 }
 657
 658 static struct spi_driver sharp_memory_spi_driver = {
 659         .driver = {
 660                 .name = "sharp_memory",
 661                 .of_match_table = sharp_memory_of_match,
 662         },
 663         .probe = sharp_memory_probe,
 664         .remove = sharp_memory_remove,
 665         .id_table = sharp_memory_ids,
 666 };
 667 module_spi_driver(sharp_memory_spi_driver);
 668
 669 MODULE_AUTHOR("Alex Lanzano <[email protected]>");
 670 MODULE_DESCRIPTION("SPI Protocol driver for the sharp_memory display");
 671 MODULE_LICENSE("GPL");