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