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_fb_helper.h>
  20 #include <drm/drm_gem_atomic_helper.h>
  21 #include <drm/drm_gem_cma_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         .enable = panel_mipi_dbi_enable,
 216         .disable = mipi_dbi_pipe_disable,
 217         .update = mipi_dbi_pipe_update,
 218 };
 219
 220 DEFINE_DRM_GEM_CMA_FOPS(panel_mipi_dbi_fops);
 221
 222 static const struct drm_driver panel_mipi_dbi_driver = {
 223         .driver_features        = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
 224         .fops                   = &panel_mipi_dbi_fops,
 225         DRM_GEM_CMA_DRIVER_OPS_VMAP,
 226         .debugfs_init           = mipi_dbi_debugfs_init,
 227         .name                   = "panel-mipi-dbi",
 228         .desc                   = "MIPI DBI compatible display panel",
 229         .date                   = "20220103",
 230         .major                  = 1,
 231         .minor                  = 0,
 232 };
 233
 234 static int panel_mipi_dbi_get_mode(struct mipi_dbi_dev *dbidev, struct drm_display_mode *mode)
 235 {
 236         struct device *dev = dbidev->drm.dev;
 237         u16 hback_porch, vback_porch;
 238         int ret;
 239
 240         ret = of_get_drm_panel_display_mode(dev->of_node, mode, NULL);
 241         if (ret) {
 242                 dev_err(dev, "%pOF: failed to get panel-timing (error=%d)\n", dev->of_node, ret);
 243                 return ret;
 244         }
 245
 246         mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
 247
 248         hback_porch = mode->htotal - mode->hsync_end;
 249         vback_porch = mode->vtotal - mode->vsync_end;
 250
 251         /*
 252          * Make sure width and height are set and that only back porch and
 253          * pixelclock are set in the other timing values. Also check that
 254          * width and height don't exceed the 16-bit value specified by MIPI DCS.
 255          */
 256         if (!mode->hdisplay || !mode->vdisplay || mode->flags ||
 257             mode->hsync_end > mode->hdisplay || (hback_porch + mode->hdisplay) > 0xffff ||
 258             mode->vsync_end > mode->vdisplay || (vback_porch + mode->vdisplay) > 0xffff) {
 259                 dev_err(dev, "%pOF: panel-timing out of bounds\n", dev->of_node);
 260                 return -EINVAL;
 261         }
 262
 263         /* The driver doesn't use the pixel clock but it is mandatory so fake one if not set */
 264         if (!mode->clock)
 265                 mode->clock = mode->htotal * mode->vtotal * 60 / 1000;
 266
 267         dbidev->top_offset = vback_porch;
 268         dbidev->left_offset = hback_porch;
 269
 270         return 0;
 271 }
 272
 273 static int panel_mipi_dbi_spi_probe(struct spi_device *spi)
 274 {
 275         struct device *dev = &spi->dev;
 276         struct drm_display_mode mode;
 277         struct mipi_dbi_dev *dbidev;
 278         struct drm_device *drm;
 279         struct mipi_dbi *dbi;
 280         struct gpio_desc *dc;
 281         int ret;
 282
 283         dbidev = devm_drm_dev_alloc(dev, &panel_mipi_dbi_driver, struct mipi_dbi_dev, drm);
 284         if (IS_ERR(dbidev))
 285                 return PTR_ERR(dbidev);
 286
 287         dbi = &dbidev->dbi;
 288         drm = &dbidev->drm;
 289
 290         ret = panel_mipi_dbi_get_mode(dbidev, &mode);
 291         if (ret)
 292                 return ret;
 293
 294         dbidev->regulator = devm_regulator_get(dev, "power");
 295         if (IS_ERR(dbidev->regulator))
 296                 return dev_err_probe(dev, PTR_ERR(dbidev->regulator),
 297                                      "Failed to get regulator 'power'\n");
 298
 299         dbidev->backlight = devm_of_find_backlight(dev);
 300         if (IS_ERR(dbidev->backlight))
 301                 return dev_err_probe(dev, PTR_ERR(dbidev->backlight), "Failed to get backlight\n");
 302
 303         dbi->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
 304         if (IS_ERR(dbi->reset))
 305                 return dev_err_probe(dev, PTR_ERR(dbi->reset), "Failed to get GPIO 'reset'\n");
 306
 307         dc = devm_gpiod_get_optional(dev, "dc", GPIOD_OUT_LOW);
 308         if (IS_ERR(dc))
 309                 return dev_err_probe(dev, PTR_ERR(dc), "Failed to get GPIO 'dc'\n");
 310
 311         ret = mipi_dbi_spi_init(spi, dbi, dc);
 312         if (ret)
 313                 return ret;
 314
 315         if (device_property_present(dev, "write-only"))
 316                 dbi->read_commands = NULL;
 317
 318         dbidev->driver_private = panel_mipi_dbi_commands_from_fw(dev);
 319         if (IS_ERR(dbidev->driver_private))
 320                 return PTR_ERR(dbidev->driver_private);
 321
 322         ret = mipi_dbi_dev_init(dbidev, &panel_mipi_dbi_pipe_funcs, &mode, 0);
 323         if (ret)
 324                 return ret;
 325
 326         drm_mode_config_reset(drm);
 327
 328         ret = drm_dev_register(drm, 0);
 329         if (ret)
 330                 return ret;
 331
 332         spi_set_drvdata(spi, drm);
 333
 334         drm_fbdev_generic_setup(drm, 0);
 335
 336         return 0;
 337 }
 338
 339 static void panel_mipi_dbi_spi_remove(struct spi_device *spi)
 340 {
 341         struct drm_device *drm = spi_get_drvdata(spi);
 342
 343         drm_dev_unplug(drm);
 344         drm_atomic_helper_shutdown(drm);
 345 }
 346
 347 static void panel_mipi_dbi_spi_shutdown(struct spi_device *spi)
 348 {
 349         drm_atomic_helper_shutdown(spi_get_drvdata(spi));
 350 }
 351
 352 static int __maybe_unused panel_mipi_dbi_pm_suspend(struct device *dev)
 353 {
 354         return drm_mode_config_helper_suspend(dev_get_drvdata(dev));
 355 }
 356
 357 static int __maybe_unused panel_mipi_dbi_pm_resume(struct device *dev)
 358 {
 359         drm_mode_config_helper_resume(dev_get_drvdata(dev));
 360
 361         return 0;
 362 }
 363
 364 static const struct dev_pm_ops panel_mipi_dbi_pm_ops = {
 365         SET_SYSTEM_SLEEP_PM_OPS(panel_mipi_dbi_pm_suspend, panel_mipi_dbi_pm_resume)
 366 };
 367
 368 static const struct of_device_id panel_mipi_dbi_spi_of_match[] = {
 369         { .compatible = "panel-mipi-dbi-spi" },
 370         {},
 371 };
 372 MODULE_DEVICE_TABLE(of, panel_mipi_dbi_spi_of_match);
 373
 374 static const struct spi_device_id panel_mipi_dbi_spi_id[] = {
 375         { "panel-mipi-dbi-spi", 0 },
 376         { },
 377 };
 378 MODULE_DEVICE_TABLE(spi, panel_mipi_dbi_spi_id);
 379
 380 static struct spi_driver panel_mipi_dbi_spi_driver = {
 381         .driver = {
 382                 .name = "panel-mipi-dbi-spi",
 383                 .owner = THIS_MODULE,
 384                 .of_match_table = panel_mipi_dbi_spi_of_match,
 385                 .pm = &panel_mipi_dbi_pm_ops,
 386         },
 387         .id_table = panel_mipi_dbi_spi_id,
 388         .probe = panel_mipi_dbi_spi_probe,
 389         .remove = panel_mipi_dbi_spi_remove,
 390         .shutdown = panel_mipi_dbi_spi_shutdown,
 391 };
 392 module_spi_driver(panel_mipi_dbi_spi_driver);
 393
 394 MODULE_DESCRIPTION("MIPI DBI compatible display panel driver");
 395 MODULE_AUTHOR("Noralf Trønnes");
 396 MODULE_LICENSE("GPL");