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/of.h> 14 #include <linux/property.h> 15 #include <linux/regulator/consumer.h> 16 #include <linux/spi/spi.h> 17 18 #include <drm/clients/drm_client_setup.h> 19 #include <drm/drm_atomic_helper.h> 20 #include <drm/drm_drv.h> 21 #include <drm/drm_fbdev_dma.h> 22 #include <drm/drm_gem_atomic_helper.h> 23 #include <drm/drm_gem_dma_helper.h> 24 #include <drm/drm_managed.h> 25 #include <drm/drm_mipi_dbi.h> 26 #include <drm/drm_modes.h> 27 #include <drm/drm_modeset_helper.h> 28 29 #include <video/mipi_display.h> 30 31 struct panel_mipi_dbi_format { 32 const char *name; 33 u32 fourcc; 34 unsigned int bpp; 35 }; 36 37 static const struct panel_mipi_dbi_format panel_mipi_dbi_formats[] = { 38 { "r5g6b5", DRM_FORMAT_RGB565, 16 }, 39 { "b6x2g6x2r6x2", DRM_FORMAT_RGB888, 24 }, 40 }; 41 42 static int panel_mipi_dbi_get_format(struct device *dev, u32 *formats, unsigned int *bpp) 43 { 44 const char *format_name; 45 unsigned int i; 46 int ret; 47 48 formats[1] = DRM_FORMAT_XRGB8888; 49 50 ret = device_property_read_string(dev, "format", &format_name); 51 if (ret) { 52 /* Old Device Trees don't have this property */ 53 formats[0] = DRM_FORMAT_RGB565; 54 *bpp = 16; 55 return 0; 56 } 57 58 for (i = 0; i < ARRAY_SIZE(panel_mipi_dbi_formats); i++) { 59 const struct panel_mipi_dbi_format *format = &panel_mipi_dbi_formats[i]; 60 61 if (strcmp(format_name, format->name)) 62 continue; 63 64 formats[0] = format->fourcc; 65 *bpp = format->bpp; 66 return 0; 67 } 68 69 dev_err(dev, "Pixel format is not supported: '%s'\n", format_name); 70 71 return -EINVAL; 72 } 73 74 static const u8 panel_mipi_dbi_magic[15] = { 'M', 'I', 'P', 'I', ' ', 'D', 'B', 'I', 75 0, 0, 0, 0, 0, 0, 0 }; 76 77 /* 78 * The display controller configuration is stored in a firmware file. 79 * The Device Tree 'compatible' property value with a '.bin' suffix is passed 80 * to request_firmware() to fetch this file. 81 */ 82 struct panel_mipi_dbi_config { 83 /* Magic string: panel_mipi_dbi_magic */ 84 u8 magic[15]; 85 86 /* Config file format version */ 87 u8 file_format_version; 88 89 /* 90 * MIPI commands to execute when the display pipeline is enabled. 91 * This is used to configure the display controller. 92 * 93 * The commands are stored in a byte array with the format: 94 * command, num_parameters, [ parameter, ...], command, ... 95 * 96 * Some commands require a pause before the next command can be received. 97 * Inserting a delay in the command sequence is done by using the NOP command with one 98 * parameter: delay in miliseconds (the No Operation command is part of the MIPI Display 99 * Command Set where it has no parameters). 100 * 101 * Example: 102 * command 0x11 103 * sleep 120ms 104 * command 0xb1 parameters 0x01, 0x2c, 0x2d 105 * command 0x29 106 * 107 * Byte sequence: 108 * 0x11 0x00 109 * 0x00 0x01 0x78 110 * 0xb1 0x03 0x01 0x2c 0x2d 111 * 0x29 0x00 112 */ 113 u8 commands[]; 114 }; 115 116 struct panel_mipi_dbi_commands { 117 const u8 *buf; 118 size_t len; 119 }; 120 121 static struct panel_mipi_dbi_commands * 122 panel_mipi_dbi_check_commands(struct device *dev, const struct firmware *fw) 123 { 124 const struct panel_mipi_dbi_config *config = (struct panel_mipi_dbi_config *)fw->data; 125 struct panel_mipi_dbi_commands *commands; 126 size_t size = fw->size, commands_len; 127 unsigned int i = 0; 128 129 if (size < sizeof(*config) + 2) { /* At least 1 command */ 130 dev_err(dev, "config: file size=%zu is too small\n", size); 131 return ERR_PTR(-EINVAL); 132 } 133 134 if (memcmp(config->magic, panel_mipi_dbi_magic, sizeof(config->magic))) { 135 dev_err(dev, "config: Bad magic: %15ph\n", config->magic); 136 return ERR_PTR(-EINVAL); 137 } 138 139 if (config->file_format_version != 1) { 140 dev_err(dev, "config: version=%u is not supported\n", config->file_format_version); 141 return ERR_PTR(-EINVAL); 142 } 143 144 drm_dev_dbg(dev, DRM_UT_DRIVER, "size=%zu version=%u\n", size, config->file_format_version); 145 146 commands_len = size - sizeof(*config); 147 148 while ((i + 1) < commands_len) { 149 u8 command = config->commands[i++]; 150 u8 num_parameters = config->commands[i++]; 151 const u8 *parameters = &config->commands[i]; 152 153 i += num_parameters; 154 if (i > commands_len) { 155 dev_err(dev, "config: command=0x%02x num_parameters=%u overflows\n", 156 command, num_parameters); 157 return ERR_PTR(-EINVAL); 158 } 159 160 if (command == 0x00 && num_parameters == 1) 161 drm_dev_dbg(dev, DRM_UT_DRIVER, "sleep %ums\n", parameters[0]); 162 else 163 drm_dev_dbg(dev, DRM_UT_DRIVER, "command %02x %*ph\n", 164 command, num_parameters, parameters); 165 } 166 167 if (i != commands_len) { 168 dev_err(dev, "config: malformed command array\n"); 169 return ERR_PTR(-EINVAL); 170 } 171 172 commands = devm_kzalloc(dev, sizeof(*commands), GFP_KERNEL); 173 if (!commands) 174 return ERR_PTR(-ENOMEM); 175 176 commands->len = commands_len; 177 commands->buf = devm_kmemdup(dev, config->commands, commands->len, GFP_KERNEL); 178 if (!commands->buf) 179 return ERR_PTR(-ENOMEM); 180 181 return commands; 182 } 183 184 static struct panel_mipi_dbi_commands *panel_mipi_dbi_commands_from_fw(struct device *dev) 185 { 186 struct panel_mipi_dbi_commands *commands; 187 const struct firmware *fw; 188 const char *compatible; 189 char fw_name[40]; 190 int ret; 191 192 ret = of_property_read_string_index(dev->of_node, "compatible", 0, &compatible); 193 if (ret) 194 return ERR_PTR(ret); 195 196 snprintf(fw_name, sizeof(fw_name), "%s.bin", compatible); 197 ret = request_firmware(&fw, fw_name, dev); 198 if (ret) { 199 dev_err(dev, "No config file found for compatible '%s' (error=%d)\n", 200 compatible, ret); 201 202 return ERR_PTR(ret); 203 } 204 205 commands = panel_mipi_dbi_check_commands(dev, fw); 206 release_firmware(fw); 207 208 return commands; 209 } 210 211 static void panel_mipi_dbi_commands_execute(struct mipi_dbi *dbi, 212 struct panel_mipi_dbi_commands *commands) 213 { 214 unsigned int i = 0; 215 216 if (!commands) 217 return; 218 219 while (i < commands->len) { 220 u8 command = commands->buf[i++]; 221 u8 num_parameters = commands->buf[i++]; 222 const u8 *parameters = &commands->buf[i]; 223 224 if (command == 0x00 && num_parameters == 1) 225 msleep(parameters[0]); 226 else if (num_parameters) 227 mipi_dbi_command_stackbuf(dbi, command, parameters, num_parameters); 228 else 229 mipi_dbi_command(dbi, command); 230 231 i += num_parameters; 232 } 233 } 234 235 static void panel_mipi_dbi_enable(struct drm_simple_display_pipe *pipe, 236 struct drm_crtc_state *crtc_state, 237 struct drm_plane_state *plane_state) 238 { 239 struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(pipe->crtc.dev); 240 struct mipi_dbi *dbi = &dbidev->dbi; 241 int ret, idx; 242 243 if (!drm_dev_enter(pipe->crtc.dev, &idx)) 244 return; 245 246 drm_dbg(pipe->crtc.dev, "\n"); 247 248 ret = mipi_dbi_poweron_conditional_reset(dbidev); 249 if (ret < 0) 250 goto out_exit; 251 if (!ret) 252 panel_mipi_dbi_commands_execute(dbi, dbidev->driver_private); 253 254 mipi_dbi_enable_flush(dbidev, crtc_state, plane_state); 255 out_exit: 256 drm_dev_exit(idx); 257 } 258 259 static const struct drm_simple_display_pipe_funcs panel_mipi_dbi_pipe_funcs = { 260 DRM_MIPI_DBI_SIMPLE_DISPLAY_PIPE_FUNCS(panel_mipi_dbi_enable), 261 }; 262 263 DEFINE_DRM_GEM_DMA_FOPS(panel_mipi_dbi_fops); 264 265 static const struct drm_driver panel_mipi_dbi_driver = { 266 .driver_features = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC, 267 .fops = &panel_mipi_dbi_fops, 268 DRM_GEM_DMA_DRIVER_OPS_VMAP, 269 DRM_FBDEV_DMA_DRIVER_OPS, 270 .debugfs_init = mipi_dbi_debugfs_init, 271 .name = "panel-mipi-dbi", 272 .desc = "MIPI DBI compatible display panel", 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"); 455