drivers/gpu/drm/tiny/panel-mipi-dbi.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * DRM driver for MIPI DBI compatible display panels
   4  *
   5  * Copyright 2022 Noralf Trønnes
   6  */
   7
   8 #include <linux/backlight.h>
   9 #include <linux/delay.h>
  10 #include <linux/firmware.h>
  11 #include <linux/gpio/consumer.h>
  12 #include <linux/module.h>
  13 #include <linux/property.h>
  14 #include <linux/regulator/consumer.h>
  15 #include <linux/spi/spi.h>
  16
  17 #include <drm/drm_atomic_helper.h>
  18 #include <drm/drm_client_setup.h>
  19 #include <drm/drm_drv.h>
  20 #include <drm/drm_fbdev_dma.h>
  21 #include <drm/drm_gem_atomic_helper.h>
  22 #include <drm/drm_gem_dma_helper.h>
  23 #include <drm/drm_managed.h>
  24 #include <drm/drm_mipi_dbi.h>
  25 #include <drm/drm_modes.h>
  26 #include <drm/drm_modeset_helper.h>
  27
  28 #include <video/mipi_display.h>
  29
  30 struct panel_mipi_dbi_format {
  31         const char *name;
  32         u32 fourcc;
  33         unsigned int bpp;
  34 };
  35
  36 static const struct panel_mipi_dbi_format panel_mipi_dbi_formats[] = {
  37         { "r5g6b5", DRM_FORMAT_RGB565, 16 },
  38         { "b6x2g6x2r6x2", DRM_FORMAT_RGB888, 24 },
  39 };
  40
  41 static int panel_mipi_dbi_get_format(struct device *dev, u32 *formats, unsigned int *bpp)
  42 {
  43         const char *format_name;
  44         unsigned int i;
  45         int ret;
  46
  47         formats[1] = DRM_FORMAT_XRGB8888;
  48
  49         ret = device_property_read_string(dev, "format", &format_name);
  50         if (ret) {
  51                 /* Old Device Trees don't have this property */
  52                 formats[0] = DRM_FORMAT_RGB565;
  53                 *bpp = 16;
  54                 return 0;
  55         }
  56
  57         for (i = 0; i < ARRAY_SIZE(panel_mipi_dbi_formats); i++) {
  58                 const struct panel_mipi_dbi_format *format = &panel_mipi_dbi_formats[i];
  59
  60                 if (strcmp(format_name, format->name))
  61                         continue;
  62
  63                 formats[0] = format->fourcc;
  64                 *bpp = format->bpp;
  65                 return 0;
  66         }
  67
  68         dev_err(dev, "Pixel format is not supported: '%s'\n", format_name);
  69
  70         return -EINVAL;
  71 }
  72
  73 static const u8 panel_mipi_dbi_magic[15] = { 'M', 'I', 'P', 'I', ' ', 'D', 'B', 'I',
  74                                              0, 0, 0, 0, 0, 0, 0 };
  75
  76 /*
  77  * The display controller configuration is stored in a firmware file.
  78  * The Device Tree 'compatible' property value with a '.bin' suffix is passed
  79  * to request_firmware() to fetch this file.
  80  */
  81 struct panel_mipi_dbi_config {
  82         /* Magic string: panel_mipi_dbi_magic */
  83         u8 magic[15];
  84
  85         /* Config file format version */
  86         u8 file_format_version;
  87
  88         /*
  89          * MIPI commands to execute when the display pipeline is enabled.
  90          * This is used to configure the display controller.
  91          *
  92          * The commands are stored in a byte array with the format:
  93          *     command, num_parameters, [ parameter, ...], command, ...
  94          *
  95          * Some commands require a pause before the next command can be received.
  96          * Inserting a delay in the command sequence is done by using the NOP command with one
  97          * parameter: delay in miliseconds (the No Operation command is part of the MIPI Display
  98          * Command Set where it has no parameters).
  99          *
 100          * Example:
 101          *     command 0x11
 102          *     sleep 120ms
 103          *     command 0xb1 parameters 0x01, 0x2c, 0x2d
 104          *     command 0x29
 105          *
 106          * Byte sequence:
 107          *     0x11 0x00
 108          *     0x00 0x01 0x78
 109          *     0xb1 0x03 0x01 0x2c 0x2d
 110          *     0x29 0x00
 111          */
 112         u8 commands[];
 113 };
 114
 115 struct panel_mipi_dbi_commands {
 116         const u8 *buf;
 117         size_t len;
 118 };
 119
 120 static struct panel_mipi_dbi_commands *
 121 panel_mipi_dbi_check_commands(struct device *dev, const struct firmware *fw)
 122 {
 123         const struct panel_mipi_dbi_config *config = (struct panel_mipi_dbi_config *)fw->data;
 124         struct panel_mipi_dbi_commands *commands;
 125         size_t size = fw->size, commands_len;
 126         unsigned int i = 0;
 127
 128         if (size < sizeof(*config) + 2) { /* At least 1 command */
 129                 dev_err(dev, "config: file size=%zu is too small\n", size);
 130                 return ERR_PTR(-EINVAL);
 131         }
 132
 133         if (memcmp(config->magic, panel_mipi_dbi_magic, sizeof(config->magic))) {
 134                 dev_err(dev, "config: Bad magic: %15ph\n", config->magic);
 135                 return ERR_PTR(-EINVAL);
 136         }
 137
 138         if (config->file_format_version != 1) {
 139                 dev_err(dev, "config: version=%u is not supported\n", config->file_format_version);
 140                 return ERR_PTR(-EINVAL);
 141         }
 142
 143         drm_dev_dbg(dev, DRM_UT_DRIVER, "size=%zu version=%u\n", size, config->file_format_version);
 144
 145         commands_len = size - sizeof(*config);
 146
 147         while ((i + 1) < commands_len) {
 148                 u8 command = config->commands[i++];
 149                 u8 num_parameters = config->commands[i++];
 150                 const u8 *parameters = &config->commands[i];
 151
 152                 i += num_parameters;
 153                 if (i > commands_len) {
 154                         dev_err(dev, "config: command=0x%02x num_parameters=%u overflows\n",
 155                                 command, num_parameters);
 156                         return ERR_PTR(-EINVAL);
 157                 }
 158
 159                 if (command == 0x00 && num_parameters == 1)
 160                         drm_dev_dbg(dev, DRM_UT_DRIVER, "sleep %ums\n", parameters[0]);
 161                 else
 162                         drm_dev_dbg(dev, DRM_UT_DRIVER, "command %02x %*ph\n",
 163                                     command, num_parameters, parameters);
 164         }
 165
 166         if (i != commands_len) {
 167                 dev_err(dev, "config: malformed command array\n");
 168                 return ERR_PTR(-EINVAL);
 169         }
 170
 171         commands = devm_kzalloc(dev, sizeof(*commands), GFP_KERNEL);
 172         if (!commands)
 173                 return ERR_PTR(-ENOMEM);
 174
 175         commands->len = commands_len;
 176         commands->buf = devm_kmemdup(dev, config->commands, commands->len, GFP_KERNEL);
 177         if (!commands->buf)
 178                 return ERR_PTR(-ENOMEM);
 179
 180         return commands;
 181 }
 182
 183 static struct panel_mipi_dbi_commands *panel_mipi_dbi_commands_from_fw(struct device *dev)
 184 {
 185         struct panel_mipi_dbi_commands *commands;
 186         const struct firmware *fw;
 187         const char *compatible;
 188         char fw_name[40];
 189         int ret;
 190
 191         ret = of_property_read_string_index(dev->of_node, "compatible", 0, &compatible);
 192         if (ret)
 193                 return ERR_PTR(ret);
 194
 195         snprintf(fw_name, sizeof(fw_name), "%s.bin", compatible);
 196         ret = request_firmware(&fw, fw_name, dev);
 197         if (ret) {
 198                 dev_err(dev, "No config file found for compatible '%s' (error=%d)\n",
 199                         compatible, ret);
 200
 201                 return ERR_PTR(ret);
 202         }
 203
 204         commands = panel_mipi_dbi_check_commands(dev, fw);
 205         release_firmware(fw);
 206
 207         return commands;
 208 }
 209
 210 static void panel_mipi_dbi_commands_execute(struct mipi_dbi *dbi,
 211                                             struct panel_mipi_dbi_commands *commands)
 212 {
 213         unsigned int i = 0;
 214
 215         if (!commands)
 216                 return;
 217
 218         while (i < commands->len) {
 219                 u8 command = commands->buf[i++];
 220                 u8 num_parameters = commands->buf[i++];
 221                 const u8 *parameters = &commands->buf[i];
 222
 223                 if (command == 0x00 && num_parameters == 1)
 224                         msleep(parameters[0]);
 225                 else if (num_parameters)
 226                         mipi_dbi_command_stackbuf(dbi, command, parameters, num_parameters);
 227                 else
 228                         mipi_dbi_command(dbi, command);
 229
 230                 i += num_parameters;
 231         }
 232 }
 233
 234 static void panel_mipi_dbi_enable(struct drm_simple_display_pipe *pipe,
 235                                   struct drm_crtc_state *crtc_state,
 236                                   struct drm_plane_state *plane_state)
 237 {
 238         struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(pipe->crtc.dev);
 239         struct mipi_dbi *dbi = &dbidev->dbi;
 240         int ret, idx;
 241
 242         if (!drm_dev_enter(pipe->crtc.dev, &idx))
 243                 return;
 244
 245         drm_dbg(pipe->crtc.dev, "\n");
 246
 247         ret = mipi_dbi_poweron_conditional_reset(dbidev);
 248         if (ret < 0)
 249                 goto out_exit;
 250         if (!ret)
 251                 panel_mipi_dbi_commands_execute(dbi, dbidev->driver_private);
 252
 253         mipi_dbi_enable_flush(dbidev, crtc_state, plane_state);
 254 out_exit:
 255         drm_dev_exit(idx);
 256 }
 257
 258 static const struct drm_simple_display_pipe_funcs panel_mipi_dbi_pipe_funcs = {
 259         DRM_MIPI_DBI_SIMPLE_DISPLAY_PIPE_FUNCS(panel_mipi_dbi_enable),
 260 };
 261
 262 DEFINE_DRM_GEM_DMA_FOPS(panel_mipi_dbi_fops);
 263
 264 static const struct drm_driver panel_mipi_dbi_driver = {
 265         .driver_features        = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
 266         .fops                   = &panel_mipi_dbi_fops,
 267         DRM_GEM_DMA_DRIVER_OPS_VMAP,
 268         DRM_FBDEV_DMA_DRIVER_OPS,
 269         .debugfs_init           = mipi_dbi_debugfs_init,
 270         .name                   = "panel-mipi-dbi",
 271         .desc                   = "MIPI DBI compatible display panel",
 272         .date                   = "20220103",
 273         .major                  = 1,
 274         .minor                  = 0,
 275 };
 276
 277 static int panel_mipi_dbi_get_mode(struct mipi_dbi_dev *dbidev, struct drm_display_mode *mode)
 278 {
 279         struct device *dev = dbidev->drm.dev;
 280         u16 hback_porch, vback_porch;
 281         int ret;
 282
 283         ret = of_get_drm_panel_display_mode(dev->of_node, mode, NULL);
 284         if (ret) {
 285                 dev_err(dev, "%pOF: failed to get panel-timing (error=%d)\n", dev->of_node, ret);
 286                 return ret;
 287         }
 288
 289         mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
 290
 291         hback_porch = mode->htotal - mode->hsync_end;
 292         vback_porch = mode->vtotal - mode->vsync_end;
 293
 294         /*
 295          * Make sure width and height are set and that only back porch and
 296          * pixelclock are set in the other timing values. Also check that
 297          * width and height don't exceed the 16-bit value specified by MIPI DCS.
 298          */
 299         if (!mode->hdisplay || !mode->vdisplay || mode->flags ||
 300             mode->hsync_end > mode->hdisplay || (hback_porch + mode->hdisplay) > 0xffff ||
 301             mode->vsync_end > mode->vdisplay || (vback_porch + mode->vdisplay) > 0xffff) {
 302                 dev_err(dev, "%pOF: panel-timing out of bounds\n", dev->of_node);
 303                 return -EINVAL;
 304         }
 305
 306         /* The driver doesn't use the pixel clock but it is mandatory so fake one if not set */
 307         if (!mode->clock)
 308                 mode->clock = mode->htotal * mode->vtotal * 60 / 1000;
 309
 310         dbidev->top_offset = vback_porch;
 311         dbidev->left_offset = hback_porch;
 312
 313         return 0;
 314 }
 315
 316 static int panel_mipi_dbi_spi_probe(struct spi_device *spi)
 317 {
 318         struct device *dev = &spi->dev;
 319         struct drm_display_mode mode;
 320         struct mipi_dbi_dev *dbidev;
 321         struct drm_device *drm;
 322         struct mipi_dbi *dbi;
 323         struct gpio_desc *dc;
 324         unsigned int bpp;
 325         size_t buf_size;
 326         u32 formats[2];
 327         int ret;
 328
 329         dbidev = devm_drm_dev_alloc(dev, &panel_mipi_dbi_driver, struct mipi_dbi_dev, drm);
 330         if (IS_ERR(dbidev))
 331                 return PTR_ERR(dbidev);
 332
 333         dbi = &dbidev->dbi;
 334         drm = &dbidev->drm;
 335
 336         ret = panel_mipi_dbi_get_mode(dbidev, &mode);
 337         if (ret)
 338                 return ret;
 339
 340         dbidev->regulator = devm_regulator_get(dev, "power");
 341         if (IS_ERR(dbidev->regulator))
 342                 return dev_err_probe(dev, PTR_ERR(dbidev->regulator),
 343                                      "Failed to get regulator 'power'\n");
 344
 345         dbidev->io_regulator = devm_regulator_get(dev, "io");
 346         if (IS_ERR(dbidev->io_regulator))
 347                 return dev_err_probe(dev, PTR_ERR(dbidev->io_regulator),
 348                                      "Failed to get regulator 'io'\n");
 349
 350         dbidev->backlight = devm_of_find_backlight(dev);
 351         if (IS_ERR(dbidev->backlight))
 352                 return dev_err_probe(dev, PTR_ERR(dbidev->backlight), "Failed to get backlight\n");
 353
 354         dbi->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
 355         if (IS_ERR(dbi->reset))
 356                 return dev_err_probe(dev, PTR_ERR(dbi->reset), "Failed to get GPIO 'reset'\n");
 357
 358         /* Multiple panels can share the "dc" GPIO, but only if they are on the same SPI bus! */
 359         dc = devm_gpiod_get_optional(dev, "dc", GPIOD_OUT_LOW | GPIOD_FLAGS_BIT_NONEXCLUSIVE);
 360         if (IS_ERR(dc))
 361                 return dev_err_probe(dev, PTR_ERR(dc), "Failed to get GPIO 'dc'\n");
 362
 363         ret = mipi_dbi_spi_init(spi, dbi, dc);
 364         if (ret)
 365                 return ret;
 366
 367         if (device_property_present(dev, "write-only"))
 368                 dbi->read_commands = NULL;
 369
 370         dbidev->driver_private = panel_mipi_dbi_commands_from_fw(dev);
 371         if (IS_ERR(dbidev->driver_private))
 372                 return PTR_ERR(dbidev->driver_private);
 373
 374         ret = panel_mipi_dbi_get_format(dev, formats, &bpp);
 375         if (ret)
 376                 return ret;
 377
 378         buf_size = DIV_ROUND_UP(mode.hdisplay * mode.vdisplay * bpp, 8);
 379         ret = mipi_dbi_dev_init_with_formats(dbidev, &panel_mipi_dbi_pipe_funcs,
 380                                              formats, ARRAY_SIZE(formats),
 381                                              &mode, 0, buf_size);
 382         if (ret)
 383                 return ret;
 384
 385         drm_mode_config_reset(drm);
 386
 387         ret = drm_dev_register(drm, 0);
 388         if (ret)
 389                 return ret;
 390
 391         spi_set_drvdata(spi, drm);
 392
 393         drm_client_setup(drm, NULL);
 394
 395         return 0;
 396 }
 397
 398 static void panel_mipi_dbi_spi_remove(struct spi_device *spi)
 399 {
 400         struct drm_device *drm = spi_get_drvdata(spi);
 401
 402         drm_dev_unplug(drm);
 403         drm_atomic_helper_shutdown(drm);
 404 }
 405
 406 static void panel_mipi_dbi_spi_shutdown(struct spi_device *spi)
 407 {
 408         drm_atomic_helper_shutdown(spi_get_drvdata(spi));
 409 }
 410
 411 static int __maybe_unused panel_mipi_dbi_pm_suspend(struct device *dev)
 412 {
 413         return drm_mode_config_helper_suspend(dev_get_drvdata(dev));
 414 }
 415
 416 static int __maybe_unused panel_mipi_dbi_pm_resume(struct device *dev)
 417 {
 418         drm_mode_config_helper_resume(dev_get_drvdata(dev));
 419
 420         return 0;
 421 }
 422
 423 static const struct dev_pm_ops panel_mipi_dbi_pm_ops = {
 424         SET_SYSTEM_SLEEP_PM_OPS(panel_mipi_dbi_pm_suspend, panel_mipi_dbi_pm_resume)
 425 };
 426
 427 static const struct of_device_id panel_mipi_dbi_spi_of_match[] = {
 428         { .compatible = "panel-mipi-dbi-spi" },
 429         {},
 430 };
 431 MODULE_DEVICE_TABLE(of, panel_mipi_dbi_spi_of_match);
 432
 433 static const struct spi_device_id panel_mipi_dbi_spi_id[] = {
 434         { "panel-mipi-dbi-spi", 0 },
 435         { },
 436 };
 437 MODULE_DEVICE_TABLE(spi, panel_mipi_dbi_spi_id);
 438
 439 static struct spi_driver panel_mipi_dbi_spi_driver = {
 440         .driver = {
 441                 .name = "panel-mipi-dbi-spi",
 442                 .of_match_table = panel_mipi_dbi_spi_of_match,
 443                 .pm = &panel_mipi_dbi_pm_ops,
 444         },
 445         .id_table = panel_mipi_dbi_spi_id,
 446         .probe = panel_mipi_dbi_spi_probe,
 447         .remove = panel_mipi_dbi_spi_remove,
 448         .shutdown = panel_mipi_dbi_spi_shutdown,
 449 };
 450 module_spi_driver(panel_mipi_dbi_spi_driver);
 451
 452 MODULE_DESCRIPTION("MIPI DBI compatible display panel driver");
 453 MODULE_AUTHOR("Noralf Trønnes");
 454 MODULE_LICENSE("GPL");