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

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