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