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 #include <drm/drm_print.h>
29
30 #include <video/mipi_display.h>
31
32 struct panel_mipi_dbi_format {
33 const char *name;
34 u32 fourcc;
35 unsigned int bpp;
36 };
37
38 static const struct panel_mipi_dbi_format panel_mipi_dbi_formats[] = {
39 { "r5g6b5", DRM_FORMAT_RGB565, 16 },
40 { "b6x2g6x2r6x2", DRM_FORMAT_RGB888, 24 },
41 };
42
panel_mipi_dbi_get_format(struct device * dev,u32 * formats,unsigned int * bpp)43 static int panel_mipi_dbi_get_format(struct device *dev, u32 *formats, unsigned int *bpp)
44 {
45 const char *format_name;
46 unsigned int i;
47 int ret;
48
49 formats[1] = DRM_FORMAT_XRGB8888;
50
51 ret = device_property_read_string(dev, "format", &format_name);
52 if (ret) {
53 /* Old Device Trees don't have this property */
54 formats[0] = DRM_FORMAT_RGB565;
55 *bpp = 16;
56 return 0;
57 }
58
59 for (i = 0; i < ARRAY_SIZE(panel_mipi_dbi_formats); i++) {
60 const struct panel_mipi_dbi_format *format = &panel_mipi_dbi_formats[i];
61
62 if (strcmp(format_name, format->name))
63 continue;
64
65 formats[0] = format->fourcc;
66 *bpp = format->bpp;
67 return 0;
68 }
69
70 dev_err(dev, "Pixel format is not supported: '%s'\n", format_name);
71
72 return -EINVAL;
73 }
74
75 static const u8 panel_mipi_dbi_magic[15] = { 'M', 'I', 'P', 'I', ' ', 'D', 'B', 'I',
76 0, 0, 0, 0, 0, 0, 0 };
77
78 /*
79 * The display controller configuration is stored in a firmware file.
80 * The Device Tree 'compatible' property value with a '.bin' suffix is passed
81 * to request_firmware() to fetch this file.
82 */
83 struct panel_mipi_dbi_config {
84 /* Magic string: panel_mipi_dbi_magic */
85 u8 magic[15];
86
87 /* Config file format version */
88 u8 file_format_version;
89
90 /*
91 * MIPI commands to execute when the display pipeline is enabled.
92 * This is used to configure the display controller.
93 *
94 * The commands are stored in a byte array with the format:
95 * command, num_parameters, [ parameter, ...], command, ...
96 *
97 * Some commands require a pause before the next command can be received.
98 * Inserting a delay in the command sequence is done by using the NOP command with one
99 * parameter: delay in miliseconds (the No Operation command is part of the MIPI Display
100 * Command Set where it has no parameters).
101 *
102 * Example:
103 * command 0x11
104 * sleep 120ms
105 * command 0xb1 parameters 0x01, 0x2c, 0x2d
106 * command 0x29
107 *
108 * Byte sequence:
109 * 0x11 0x00
110 * 0x00 0x01 0x78
111 * 0xb1 0x03 0x01 0x2c 0x2d
112 * 0x29 0x00
113 */
114 u8 commands[];
115 };
116
117 struct panel_mipi_dbi_commands {
118 const u8 *buf;
119 size_t len;
120 };
121
122 static struct panel_mipi_dbi_commands *
panel_mipi_dbi_check_commands(struct device * dev,const struct firmware * fw)123 panel_mipi_dbi_check_commands(struct device *dev, const struct firmware *fw)
124 {
125 const struct panel_mipi_dbi_config *config = (struct panel_mipi_dbi_config *)fw->data;
126 struct panel_mipi_dbi_commands *commands;
127 size_t size = fw->size, commands_len;
128 unsigned int i = 0;
129
130 if (size < sizeof(*config) + 2) { /* At least 1 command */
131 dev_err(dev, "config: file size=%zu is too small\n", size);
132 return ERR_PTR(-EINVAL);
133 }
134
135 if (memcmp(config->magic, panel_mipi_dbi_magic, sizeof(config->magic))) {
136 dev_err(dev, "config: Bad magic: %15ph\n", config->magic);
137 return ERR_PTR(-EINVAL);
138 }
139
140 if (config->file_format_version != 1) {
141 dev_err(dev, "config: version=%u is not supported\n", config->file_format_version);
142 return ERR_PTR(-EINVAL);
143 }
144
145 drm_dev_dbg(dev, DRM_UT_DRIVER, "size=%zu version=%u\n", size, config->file_format_version);
146
147 commands_len = size - sizeof(*config);
148
149 while ((i + 1) < commands_len) {
150 u8 command = config->commands[i++];
151 u8 num_parameters = config->commands[i++];
152 const u8 *parameters = &config->commands[i];
153
154 i += num_parameters;
155 if (i > commands_len) {
156 dev_err(dev, "config: command=0x%02x num_parameters=%u overflows\n",
157 command, num_parameters);
158 return ERR_PTR(-EINVAL);
159 }
160
161 if (command == 0x00 && num_parameters == 1)
162 drm_dev_dbg(dev, DRM_UT_DRIVER, "sleep %ums\n", parameters[0]);
163 else
164 drm_dev_dbg(dev, DRM_UT_DRIVER, "command %02x %*ph\n",
165 command, num_parameters, parameters);
166 }
167
168 if (i != commands_len) {
169 dev_err(dev, "config: malformed command array\n");
170 return ERR_PTR(-EINVAL);
171 }
172
173 commands = devm_kzalloc(dev, sizeof(*commands), GFP_KERNEL);
174 if (!commands)
175 return ERR_PTR(-ENOMEM);
176
177 commands->len = commands_len;
178 commands->buf = devm_kmemdup(dev, config->commands, commands->len, GFP_KERNEL);
179 if (!commands->buf)
180 return ERR_PTR(-ENOMEM);
181
182 return commands;
183 }
184
panel_mipi_dbi_commands_from_fw(struct device * dev)185 static struct panel_mipi_dbi_commands *panel_mipi_dbi_commands_from_fw(struct device *dev)
186 {
187 struct panel_mipi_dbi_commands *commands;
188 const struct firmware *fw;
189 const char *compatible;
190 char fw_name[40];
191 int ret;
192
193 ret = of_property_read_string_index(dev->of_node, "compatible", 0, &compatible);
194 if (ret)
195 return ERR_PTR(ret);
196
197 snprintf(fw_name, sizeof(fw_name), "%s.bin", compatible);
198 ret = request_firmware(&fw, fw_name, dev);
199 if (ret) {
200 dev_err(dev, "No config file found for compatible '%s' (error=%d)\n",
201 compatible, ret);
202
203 return ERR_PTR(ret);
204 }
205
206 commands = panel_mipi_dbi_check_commands(dev, fw);
207 release_firmware(fw);
208
209 return commands;
210 }
211
panel_mipi_dbi_commands_execute(struct mipi_dbi * dbi,struct panel_mipi_dbi_commands * commands)212 static void panel_mipi_dbi_commands_execute(struct mipi_dbi *dbi,
213 struct panel_mipi_dbi_commands *commands)
214 {
215 unsigned int i = 0;
216
217 if (!commands)
218 return;
219
220 while (i < commands->len) {
221 u8 command = commands->buf[i++];
222 u8 num_parameters = commands->buf[i++];
223 const u8 *parameters = &commands->buf[i];
224
225 if (command == 0x00 && num_parameters == 1)
226 msleep(parameters[0]);
227 else if (num_parameters)
228 mipi_dbi_command_stackbuf(dbi, command, parameters, num_parameters);
229 else
230 mipi_dbi_command(dbi, command);
231
232 i += num_parameters;
233 }
234 }
235
236 struct panel_mipi_dbi_device {
237 struct mipi_dbi_dev dbidev;
238
239 struct drm_plane plane;
240 struct drm_crtc crtc;
241 struct drm_encoder encoder;
242 struct drm_connector connector;
243 };
244
to_panel_mipi_dbi_device(struct drm_device * dev)245 static struct panel_mipi_dbi_device *to_panel_mipi_dbi_device(struct drm_device *dev)
246 {
247 return container_of(drm_to_mipi_dbi_dev(dev), struct panel_mipi_dbi_device, dbidev);
248 }
249
250 static const u64 panel_mipi_dbi_plane_format_modifiers[] = {
251 DRM_MIPI_DBI_PLANE_FORMAT_MODIFIERS,
252 };
253
254 static const struct drm_plane_helper_funcs panel_mipi_dbi_plane_helper_funcs = {
255 DRM_MIPI_DBI_PLANE_HELPER_FUNCS,
256 };
257
258 static const struct drm_plane_funcs panel_mipi_dbi_plane_funcs = {
259 DRM_MIPI_DBI_PLANE_FUNCS,
260 .destroy = drm_plane_cleanup,
261 };
262
panel_mipi_dbi_crtc_helper_atomic_enable(struct drm_crtc * crtc,struct drm_atomic_state * state)263 static void panel_mipi_dbi_crtc_helper_atomic_enable(struct drm_crtc *crtc,
264 struct drm_atomic_state *state)
265 {
266 struct drm_device *drm = crtc->dev;
267 struct panel_mipi_dbi_device *panel_mipi_dbi = to_panel_mipi_dbi_device(drm);
268 struct mipi_dbi_dev *dbidev = &panel_mipi_dbi->dbidev;
269 struct mipi_dbi *dbi = &dbidev->dbi;
270 int ret, idx;
271
272 if (!drm_dev_enter(drm, &idx))
273 return;
274
275 drm_dbg(drm, "\n");
276
277 ret = mipi_dbi_poweron_conditional_reset(dbidev);
278 if (ret < 0)
279 goto out_exit;
280 if (!ret)
281 panel_mipi_dbi_commands_execute(dbi, dbidev->driver_private);
282
283 backlight_enable(dbidev->backlight);
284 out_exit:
285 drm_dev_exit(idx);
286 }
287
288 static const struct drm_crtc_helper_funcs panel_mipi_dbi_crtc_helper_funcs = {
289 DRM_MIPI_DBI_CRTC_HELPER_FUNCS,
290 .atomic_enable = panel_mipi_dbi_crtc_helper_atomic_enable,
291 };
292
293 static const struct drm_crtc_funcs panel_mipi_dbi_crtc_funcs = {
294 DRM_MIPI_DBI_CRTC_FUNCS,
295 .destroy = drm_crtc_cleanup,
296 };
297
298 static const struct drm_encoder_funcs panel_mipi_dbi_encoder_funcs = {
299 .destroy = drm_encoder_cleanup,
300 };
301
302 static const struct drm_connector_helper_funcs panel_mipi_dbi_connector_helper_funcs = {
303 DRM_MIPI_DBI_CONNECTOR_HELPER_FUNCS,
304 };
305
306 static const struct drm_connector_funcs panel_mipi_dbi_connector_funcs = {
307 DRM_MIPI_DBI_CONNECTOR_FUNCS,
308 .destroy = drm_connector_cleanup,
309 };
310
311 static const struct drm_mode_config_helper_funcs panel_mipi_dbi_mode_config_helper_funcs = {
312 DRM_MIPI_DBI_MODE_CONFIG_HELPER_FUNCS,
313 };
314
315 static const struct drm_mode_config_funcs panel_mipi_dbi_mode_config_funcs = {
316 DRM_MIPI_DBI_MODE_CONFIG_FUNCS,
317 };
318
319 DEFINE_DRM_GEM_DMA_FOPS(panel_mipi_dbi_fops);
320
321 static const struct drm_driver panel_mipi_dbi_driver = {
322 .driver_features = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
323 .fops = &panel_mipi_dbi_fops,
324 DRM_GEM_DMA_DRIVER_OPS_VMAP,
325 DRM_FBDEV_DMA_DRIVER_OPS,
326 .debugfs_init = mipi_dbi_debugfs_init,
327 .name = "panel-mipi-dbi",
328 .desc = "MIPI DBI compatible display panel",
329 .major = 1,
330 .minor = 0,
331 };
332
panel_mipi_dbi_get_mode(struct mipi_dbi_dev * dbidev,struct drm_display_mode * mode)333 static int panel_mipi_dbi_get_mode(struct mipi_dbi_dev *dbidev, struct drm_display_mode *mode)
334 {
335 struct device *dev = dbidev->drm.dev;
336 u16 hback_porch, vback_porch;
337 int ret;
338
339 ret = of_get_drm_panel_display_mode(dev->of_node, mode, NULL);
340 if (ret) {
341 dev_err(dev, "%pOF: failed to get panel-timing (error=%d)\n", dev->of_node, ret);
342 return ret;
343 }
344
345 mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
346
347 hback_porch = mode->htotal - mode->hsync_end;
348 vback_porch = mode->vtotal - mode->vsync_end;
349
350 /*
351 * Make sure width and height are set and that only back porch and
352 * pixelclock are set in the other timing values. Also check that
353 * width and height don't exceed the 16-bit value specified by MIPI DCS.
354 */
355 if (!mode->hdisplay || !mode->vdisplay || mode->flags ||
356 mode->hsync_end > mode->hdisplay || (hback_porch + mode->hdisplay) > 0xffff ||
357 mode->vsync_end > mode->vdisplay || (vback_porch + mode->vdisplay) > 0xffff) {
358 dev_err(dev, "%pOF: panel-timing out of bounds\n", dev->of_node);
359 return -EINVAL;
360 }
361
362 /* The driver doesn't use the pixel clock but it is mandatory so fake one if not set */
363 if (!mode->clock)
364 mode->clock = mode->htotal * mode->vtotal * 60 / 1000;
365
366 dbidev->top_offset = vback_porch;
367 dbidev->left_offset = hback_porch;
368
369 return 0;
370 }
371
panel_mipi_dbi_spi_probe(struct spi_device * spi)372 static int panel_mipi_dbi_spi_probe(struct spi_device *spi)
373 {
374 struct device *dev = &spi->dev;
375 struct panel_mipi_dbi_device *panel_mipi_dbi;
376 struct mipi_dbi_dev *dbidev;
377 struct drm_device *drm;
378 struct drm_display_mode mode;
379 struct mipi_dbi *dbi;
380 struct gpio_desc *dc;
381 unsigned int bpp;
382 size_t buf_size;
383 u32 formats[2];
384 struct drm_plane *plane;
385 struct drm_crtc *crtc;
386 struct drm_encoder *encoder;
387 struct drm_connector *connector;
388 int ret;
389
390 panel_mipi_dbi = devm_drm_dev_alloc(dev, &panel_mipi_dbi_driver,
391 struct panel_mipi_dbi_device,
392 dbidev.drm);
393 if (IS_ERR(panel_mipi_dbi))
394 return PTR_ERR(panel_mipi_dbi);
395 dbidev = &panel_mipi_dbi->dbidev;
396 dbi = &dbidev->dbi;
397 drm = &dbidev->drm;
398
399 ret = panel_mipi_dbi_get_mode(dbidev, &mode);
400 if (ret)
401 return ret;
402
403 dbidev->regulator = devm_regulator_get(dev, "power");
404 if (IS_ERR(dbidev->regulator))
405 return dev_err_probe(dev, PTR_ERR(dbidev->regulator),
406 "Failed to get regulator 'power'\n");
407
408 dbidev->io_regulator = devm_regulator_get(dev, "io");
409 if (IS_ERR(dbidev->io_regulator))
410 return dev_err_probe(dev, PTR_ERR(dbidev->io_regulator),
411 "Failed to get regulator 'io'\n");
412
413 dbidev->backlight = devm_of_find_backlight(dev);
414 if (IS_ERR(dbidev->backlight))
415 return dev_err_probe(dev, PTR_ERR(dbidev->backlight), "Failed to get backlight\n");
416
417 dbi->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
418 if (IS_ERR(dbi->reset))
419 return dev_err_probe(dev, PTR_ERR(dbi->reset), "Failed to get GPIO 'reset'\n");
420
421 /* Multiple panels can share the "dc" GPIO, but only if they are on the same SPI bus! */
422 dc = devm_gpiod_get_optional(dev, "dc", GPIOD_OUT_LOW | GPIOD_FLAGS_BIT_NONEXCLUSIVE);
423 if (IS_ERR(dc))
424 return dev_err_probe(dev, PTR_ERR(dc), "Failed to get GPIO 'dc'\n");
425
426 ret = mipi_dbi_spi_init(spi, dbi, dc);
427 if (ret)
428 return ret;
429
430 if (device_property_present(dev, "write-only"))
431 dbi->read_commands = NULL;
432
433 dbidev->driver_private = panel_mipi_dbi_commands_from_fw(dev);
434 if (IS_ERR(dbidev->driver_private))
435 return PTR_ERR(dbidev->driver_private);
436
437 ret = panel_mipi_dbi_get_format(dev, formats, &bpp);
438 if (ret)
439 return ret;
440
441 buf_size = DIV_ROUND_UP(mode.hdisplay * mode.vdisplay * bpp, 8);
442 ret = drm_mipi_dbi_dev_init(dbidev, &mode, formats[0], 0, buf_size);
443 if (ret)
444 return ret;
445
446 ret = drmm_mode_config_init(drm);
447 if (ret)
448 return ret;
449
450 drm->mode_config.min_width = dbidev->mode.hdisplay;
451 drm->mode_config.max_width = dbidev->mode.hdisplay;
452 drm->mode_config.min_height = dbidev->mode.vdisplay;
453 drm->mode_config.max_height = dbidev->mode.vdisplay;
454 drm->mode_config.funcs = &panel_mipi_dbi_mode_config_funcs;
455 drm->mode_config.preferred_depth = bpp;
456 drm->mode_config.helper_private = &panel_mipi_dbi_mode_config_helper_funcs;
457
458 plane = &panel_mipi_dbi->plane;
459 ret = drm_universal_plane_init(drm, plane, 0, &panel_mipi_dbi_plane_funcs,
460 formats, ARRAY_SIZE(formats),
461 panel_mipi_dbi_plane_format_modifiers,
462 DRM_PLANE_TYPE_PRIMARY, NULL);
463 if (ret)
464 return ret;
465 drm_plane_helper_add(plane, &panel_mipi_dbi_plane_helper_funcs);
466 drm_plane_enable_fb_damage_clips(plane);
467
468 crtc = &panel_mipi_dbi->crtc;
469 ret = drm_crtc_init_with_planes(drm, crtc, plane, NULL, &panel_mipi_dbi_crtc_funcs,
470 NULL);
471 if (ret)
472 return ret;
473 drm_crtc_helper_add(crtc, &panel_mipi_dbi_crtc_helper_funcs);
474
475 encoder = &panel_mipi_dbi->encoder;
476 ret = drm_encoder_init(drm, encoder, &panel_mipi_dbi_encoder_funcs,
477 DRM_MODE_ENCODER_NONE, NULL);
478 if (ret)
479 return ret;
480 encoder->possible_crtcs = drm_crtc_mask(crtc);
481
482 connector = &panel_mipi_dbi->connector;
483 ret = drm_connector_init(drm, connector, &panel_mipi_dbi_connector_funcs,
484 DRM_MODE_CONNECTOR_SPI);
485 if (ret)
486 return ret;
487 drm_connector_helper_add(connector, &panel_mipi_dbi_connector_helper_funcs);
488
489 ret = drm_connector_attach_encoder(connector, encoder);
490 if (ret)
491 return ret;
492
493 drm_mode_config_reset(drm);
494
495 ret = drm_dev_register(drm, 0);
496 if (ret)
497 return ret;
498
499 spi_set_drvdata(spi, drm);
500
501 if (bpp == 16)
502 drm_client_setup_with_fourcc(drm, DRM_FORMAT_RGB565);
503 else
504 drm_client_setup_with_fourcc(drm, DRM_FORMAT_RGB888);
505
506 return 0;
507 }
508
panel_mipi_dbi_spi_remove(struct spi_device * spi)509 static void panel_mipi_dbi_spi_remove(struct spi_device *spi)
510 {
511 struct drm_device *drm = spi_get_drvdata(spi);
512
513 drm_dev_unplug(drm);
514 drm_atomic_helper_shutdown(drm);
515 }
516
panel_mipi_dbi_spi_shutdown(struct spi_device * spi)517 static void panel_mipi_dbi_spi_shutdown(struct spi_device *spi)
518 {
519 drm_atomic_helper_shutdown(spi_get_drvdata(spi));
520 }
521
panel_mipi_dbi_pm_suspend(struct device * dev)522 static int __maybe_unused panel_mipi_dbi_pm_suspend(struct device *dev)
523 {
524 return drm_mode_config_helper_suspend(dev_get_drvdata(dev));
525 }
526
panel_mipi_dbi_pm_resume(struct device * dev)527 static int __maybe_unused panel_mipi_dbi_pm_resume(struct device *dev)
528 {
529 drm_mode_config_helper_resume(dev_get_drvdata(dev));
530
531 return 0;
532 }
533
534 static const struct dev_pm_ops panel_mipi_dbi_pm_ops = {
535 SET_SYSTEM_SLEEP_PM_OPS(panel_mipi_dbi_pm_suspend, panel_mipi_dbi_pm_resume)
536 };
537
538 static const struct of_device_id panel_mipi_dbi_spi_of_match[] = {
539 { .compatible = "panel-mipi-dbi-spi" },
540 {},
541 };
542 MODULE_DEVICE_TABLE(of, panel_mipi_dbi_spi_of_match);
543
544 static const struct spi_device_id panel_mipi_dbi_spi_id[] = {
545 { "panel-mipi-dbi-spi", 0 },
546 { },
547 };
548 MODULE_DEVICE_TABLE(spi, panel_mipi_dbi_spi_id);
549
550 static struct spi_driver panel_mipi_dbi_spi_driver = {
551 .driver = {
552 .name = "panel-mipi-dbi-spi",
553 .of_match_table = panel_mipi_dbi_spi_of_match,
554 .pm = &panel_mipi_dbi_pm_ops,
555 },
556 .id_table = panel_mipi_dbi_spi_id,
557 .probe = panel_mipi_dbi_spi_probe,
558 .remove = panel_mipi_dbi_spi_remove,
559 .shutdown = panel_mipi_dbi_spi_shutdown,
560 };
561 module_spi_driver(panel_mipi_dbi_spi_driver);
562
563 MODULE_DESCRIPTION("MIPI DBI compatible display panel driver");
564 MODULE_AUTHOR("Noralf Trønnes");
565 MODULE_LICENSE("GPL");
566