xref: /linux/drivers/gpu/drm/tiny/panel-mipi-dbi.c (revision 5ea5880764cbb164afb17a62e76ca75dc371409d) 
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 
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 *
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 
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 
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 
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 
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 
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 
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 
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 
517 static void panel_mipi_dbi_spi_shutdown(struct spi_device *spi)
518 {
519 	drm_atomic_helper_shutdown(spi_get_drvdata(spi));
520 }
521 
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 
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