xref: /openbmc/linux/drivers/gpu/drm/vc4/vc4_dpi.c (revision 23c2b932)
1 /*
2  * Copyright (C) 2016 Broadcom Limited
3  *
4  * This program is free software; you can redistribute it and/or modify it
5  * under the terms of the GNU General Public License version 2 as published by
6  * the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful, but WITHOUT
9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
11  * more details.
12  *
13  * You should have received a copy of the GNU General Public License along with
14  * this program.  If not, see <http://www.gnu.org/licenses/>.
15  */
16 
17 /**
18  * DOC: VC4 DPI module
19  *
20  * The VC4 DPI hardware supports MIPI DPI type 4 and Nokia ViSSI
21  * signals, which are routed out to GPIO0-27 with the ALT2 function.
22  */
23 
24 #include "drm_atomic_helper.h"
25 #include "drm_crtc_helper.h"
26 #include "drm_edid.h"
27 #include "drm_panel.h"
28 #include "linux/clk.h"
29 #include "linux/component.h"
30 #include "linux/of_graph.h"
31 #include "linux/of_platform.h"
32 #include "vc4_drv.h"
33 #include "vc4_regs.h"
34 
35 #define DPI_C			0x00
36 # define DPI_OUTPUT_ENABLE_MODE		BIT(16)
37 
38 /* The order field takes the incoming 24 bit RGB from the pixel valve
39  * and shuffles the 3 channels.
40  */
41 # define DPI_ORDER_MASK			VC4_MASK(15, 14)
42 # define DPI_ORDER_SHIFT		14
43 # define DPI_ORDER_RGB			0
44 # define DPI_ORDER_BGR			1
45 # define DPI_ORDER_GRB			2
46 # define DPI_ORDER_BRG			3
47 
48 /* The format field takes the ORDER-shuffled pixel valve data and
49  * formats it onto the output lines.
50  */
51 # define DPI_FORMAT_MASK		VC4_MASK(13, 11)
52 # define DPI_FORMAT_SHIFT		11
53 /* This define is named in the hardware, but actually just outputs 0. */
54 # define DPI_FORMAT_9BIT_666_RGB	0
55 /* Outputs 00000000rrrrrggggggbbbbb */
56 # define DPI_FORMAT_16BIT_565_RGB_1	1
57 /* Outputs 000rrrrr00gggggg000bbbbb */
58 # define DPI_FORMAT_16BIT_565_RGB_2	2
59 /* Outputs 00rrrrr000gggggg00bbbbb0 */
60 # define DPI_FORMAT_16BIT_565_RGB_3	3
61 /* Outputs 000000rrrrrrggggggbbbbbb */
62 # define DPI_FORMAT_18BIT_666_RGB_1	4
63 /* Outputs 00rrrrrr00gggggg00bbbbbb */
64 # define DPI_FORMAT_18BIT_666_RGB_2	5
65 /* Outputs rrrrrrrrggggggggbbbbbbbb */
66 # define DPI_FORMAT_24BIT_888_RGB	6
67 
68 /* Reverses the polarity of the corresponding signal */
69 # define DPI_PIXEL_CLK_INVERT		BIT(10)
70 # define DPI_HSYNC_INVERT		BIT(9)
71 # define DPI_VSYNC_INVERT		BIT(8)
72 # define DPI_OUTPUT_ENABLE_INVERT	BIT(7)
73 
74 /* Outputs the signal the falling clock edge instead of rising. */
75 # define DPI_HSYNC_NEGATE		BIT(6)
76 # define DPI_VSYNC_NEGATE		BIT(5)
77 # define DPI_OUTPUT_ENABLE_NEGATE	BIT(4)
78 
79 /* Disables the signal */
80 # define DPI_HSYNC_DISABLE		BIT(3)
81 # define DPI_VSYNC_DISABLE		BIT(2)
82 # define DPI_OUTPUT_ENABLE_DISABLE	BIT(1)
83 
84 /* Power gate to the device, full reset at 0 -> 1 transition */
85 # define DPI_ENABLE			BIT(0)
86 
87 /* All other registers besides DPI_C return the ID */
88 #define DPI_ID			0x04
89 # define DPI_ID_VALUE		0x00647069
90 
91 /* General DPI hardware state. */
92 struct vc4_dpi {
93 	struct platform_device *pdev;
94 
95 	struct drm_encoder *encoder;
96 	struct drm_connector *connector;
97 	struct drm_panel *panel;
98 
99 	void __iomem *regs;
100 
101 	struct clk *pixel_clock;
102 	struct clk *core_clock;
103 };
104 
105 #define DPI_READ(offset) readl(dpi->regs + (offset))
106 #define DPI_WRITE(offset, val) writel(val, dpi->regs + (offset))
107 
108 /* VC4 DPI encoder KMS struct */
109 struct vc4_dpi_encoder {
110 	struct vc4_encoder base;
111 	struct vc4_dpi *dpi;
112 };
113 
114 static inline struct vc4_dpi_encoder *
115 to_vc4_dpi_encoder(struct drm_encoder *encoder)
116 {
117 	return container_of(encoder, struct vc4_dpi_encoder, base.base);
118 }
119 
120 /* VC4 DPI connector KMS struct */
121 struct vc4_dpi_connector {
122 	struct drm_connector base;
123 	struct vc4_dpi *dpi;
124 
125 	/* Since the connector is attached to just the one encoder,
126 	 * this is the reference to it so we can do the best_encoder()
127 	 * hook.
128 	 */
129 	struct drm_encoder *encoder;
130 };
131 
132 static inline struct vc4_dpi_connector *
133 to_vc4_dpi_connector(struct drm_connector *connector)
134 {
135 	return container_of(connector, struct vc4_dpi_connector, base);
136 }
137 
138 #define DPI_REG(reg) { reg, #reg }
139 static const struct {
140 	u32 reg;
141 	const char *name;
142 } dpi_regs[] = {
143 	DPI_REG(DPI_C),
144 	DPI_REG(DPI_ID),
145 };
146 
147 static void vc4_dpi_dump_regs(struct vc4_dpi *dpi)
148 {
149 	int i;
150 
151 	for (i = 0; i < ARRAY_SIZE(dpi_regs); i++) {
152 		DRM_INFO("0x%04x (%s): 0x%08x\n",
153 			 dpi_regs[i].reg, dpi_regs[i].name,
154 			 DPI_READ(dpi_regs[i].reg));
155 	}
156 }
157 
158 #ifdef CONFIG_DEBUG_FS
159 int vc4_dpi_debugfs_regs(struct seq_file *m, void *unused)
160 {
161 	struct drm_info_node *node = (struct drm_info_node *)m->private;
162 	struct drm_device *dev = node->minor->dev;
163 	struct vc4_dev *vc4 = to_vc4_dev(dev);
164 	struct vc4_dpi *dpi = vc4->dpi;
165 	int i;
166 
167 	if (!dpi)
168 		return 0;
169 
170 	for (i = 0; i < ARRAY_SIZE(dpi_regs); i++) {
171 		seq_printf(m, "%s (0x%04x): 0x%08x\n",
172 			   dpi_regs[i].name, dpi_regs[i].reg,
173 			   DPI_READ(dpi_regs[i].reg));
174 	}
175 
176 	return 0;
177 }
178 #endif
179 
180 static enum drm_connector_status
181 vc4_dpi_connector_detect(struct drm_connector *connector, bool force)
182 {
183 	struct vc4_dpi_connector *vc4_connector =
184 		to_vc4_dpi_connector(connector);
185 	struct vc4_dpi *dpi = vc4_connector->dpi;
186 
187 	if (dpi->panel)
188 		return connector_status_connected;
189 	else
190 		return connector_status_disconnected;
191 }
192 
193 static void vc4_dpi_connector_destroy(struct drm_connector *connector)
194 {
195 	drm_connector_unregister(connector);
196 	drm_connector_cleanup(connector);
197 }
198 
199 static int vc4_dpi_connector_get_modes(struct drm_connector *connector)
200 {
201 	struct vc4_dpi_connector *vc4_connector =
202 		to_vc4_dpi_connector(connector);
203 	struct vc4_dpi *dpi = vc4_connector->dpi;
204 
205 	if (dpi->panel)
206 		return drm_panel_get_modes(dpi->panel);
207 
208 	return 0;
209 }
210 
211 static struct drm_encoder *
212 vc4_dpi_connector_best_encoder(struct drm_connector *connector)
213 {
214 	struct vc4_dpi_connector *dpi_connector =
215 		to_vc4_dpi_connector(connector);
216 	return dpi_connector->encoder;
217 }
218 
219 static const struct drm_connector_funcs vc4_dpi_connector_funcs = {
220 	.dpms = drm_atomic_helper_connector_dpms,
221 	.detect = vc4_dpi_connector_detect,
222 	.fill_modes = drm_helper_probe_single_connector_modes,
223 	.destroy = vc4_dpi_connector_destroy,
224 	.reset = drm_atomic_helper_connector_reset,
225 	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
226 	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
227 };
228 
229 static const struct drm_connector_helper_funcs vc4_dpi_connector_helper_funcs = {
230 	.get_modes = vc4_dpi_connector_get_modes,
231 	.best_encoder = vc4_dpi_connector_best_encoder,
232 };
233 
234 static struct drm_connector *vc4_dpi_connector_init(struct drm_device *dev,
235 						    struct vc4_dpi *dpi)
236 {
237 	struct drm_connector *connector = NULL;
238 	struct vc4_dpi_connector *dpi_connector;
239 	int ret = 0;
240 
241 	dpi_connector = devm_kzalloc(dev->dev, sizeof(*dpi_connector),
242 				     GFP_KERNEL);
243 	if (!dpi_connector) {
244 		ret = -ENOMEM;
245 		goto fail;
246 	}
247 	connector = &dpi_connector->base;
248 
249 	dpi_connector->encoder = dpi->encoder;
250 	dpi_connector->dpi = dpi;
251 
252 	drm_connector_init(dev, connector, &vc4_dpi_connector_funcs,
253 			   DRM_MODE_CONNECTOR_DPI);
254 	drm_connector_helper_add(connector, &vc4_dpi_connector_helper_funcs);
255 
256 	connector->polled = 0;
257 	connector->interlace_allowed = 0;
258 	connector->doublescan_allowed = 0;
259 
260 	drm_mode_connector_attach_encoder(connector, dpi->encoder);
261 
262 	return connector;
263 
264  fail:
265 	if (connector)
266 		vc4_dpi_connector_destroy(connector);
267 
268 	return ERR_PTR(ret);
269 }
270 
271 static const struct drm_encoder_funcs vc4_dpi_encoder_funcs = {
272 	.destroy = drm_encoder_cleanup,
273 };
274 
275 static void vc4_dpi_encoder_disable(struct drm_encoder *encoder)
276 {
277 	struct vc4_dpi_encoder *vc4_encoder = to_vc4_dpi_encoder(encoder);
278 	struct vc4_dpi *dpi = vc4_encoder->dpi;
279 
280 	drm_panel_disable(dpi->panel);
281 
282 	clk_disable_unprepare(dpi->pixel_clock);
283 
284 	drm_panel_unprepare(dpi->panel);
285 }
286 
287 static void vc4_dpi_encoder_enable(struct drm_encoder *encoder)
288 {
289 	struct drm_display_mode *mode = &encoder->crtc->mode;
290 	struct vc4_dpi_encoder *vc4_encoder = to_vc4_dpi_encoder(encoder);
291 	struct vc4_dpi *dpi = vc4_encoder->dpi;
292 	u32 dpi_c = DPI_ENABLE | DPI_OUTPUT_ENABLE_MODE;
293 	int ret;
294 
295 	ret = drm_panel_prepare(dpi->panel);
296 	if (ret) {
297 		DRM_ERROR("Panel failed to prepare\n");
298 		return;
299 	}
300 
301 	if (dpi->connector->display_info.num_bus_formats) {
302 		u32 bus_format = dpi->connector->display_info.bus_formats[0];
303 
304 		switch (bus_format) {
305 		case MEDIA_BUS_FMT_RGB888_1X24:
306 			dpi_c |= VC4_SET_FIELD(DPI_FORMAT_24BIT_888_RGB,
307 					       DPI_FORMAT);
308 			break;
309 		case MEDIA_BUS_FMT_BGR888_1X24:
310 			dpi_c |= VC4_SET_FIELD(DPI_FORMAT_24BIT_888_RGB,
311 					       DPI_FORMAT);
312 			dpi_c |= VC4_SET_FIELD(DPI_ORDER_BGR, DPI_ORDER);
313 			break;
314 		case MEDIA_BUS_FMT_RGB666_1X24_CPADHI:
315 			dpi_c |= VC4_SET_FIELD(DPI_FORMAT_18BIT_666_RGB_2,
316 					       DPI_FORMAT);
317 			break;
318 		case MEDIA_BUS_FMT_RGB666_1X18:
319 			dpi_c |= VC4_SET_FIELD(DPI_FORMAT_18BIT_666_RGB_1,
320 					       DPI_FORMAT);
321 			break;
322 		case MEDIA_BUS_FMT_RGB565_1X16:
323 			dpi_c |= VC4_SET_FIELD(DPI_FORMAT_16BIT_565_RGB_3,
324 					       DPI_FORMAT);
325 			break;
326 		default:
327 			DRM_ERROR("Unknown media bus format %d\n", bus_format);
328 			break;
329 		}
330 	}
331 
332 	if (mode->flags & DRM_MODE_FLAG_NHSYNC)
333 		dpi_c |= DPI_HSYNC_INVERT;
334 	else if (!(mode->flags & DRM_MODE_FLAG_PHSYNC))
335 		dpi_c |= DPI_HSYNC_DISABLE;
336 
337 	if (mode->flags & DRM_MODE_FLAG_NVSYNC)
338 		dpi_c |= DPI_VSYNC_INVERT;
339 	else if (!(mode->flags & DRM_MODE_FLAG_PVSYNC))
340 		dpi_c |= DPI_VSYNC_DISABLE;
341 
342 	DPI_WRITE(DPI_C, dpi_c);
343 
344 	ret = clk_set_rate(dpi->pixel_clock, mode->clock * 1000);
345 	if (ret)
346 		DRM_ERROR("Failed to set clock rate: %d\n", ret);
347 
348 	ret = clk_prepare_enable(dpi->pixel_clock);
349 	if (ret)
350 		DRM_ERROR("Failed to set clock rate: %d\n", ret);
351 
352 	ret = drm_panel_enable(dpi->panel);
353 	if (ret) {
354 		DRM_ERROR("Panel failed to enable\n");
355 		drm_panel_unprepare(dpi->panel);
356 		return;
357 	}
358 }
359 
360 static const struct drm_encoder_helper_funcs vc4_dpi_encoder_helper_funcs = {
361 	.disable = vc4_dpi_encoder_disable,
362 	.enable = vc4_dpi_encoder_enable,
363 };
364 
365 static const struct of_device_id vc4_dpi_dt_match[] = {
366 	{ .compatible = "brcm,bcm2835-dpi", .data = NULL },
367 	{}
368 };
369 
370 /* Walks the OF graph to find the panel node and then asks DRM to look
371  * up the panel.
372  */
373 static struct drm_panel *vc4_dpi_get_panel(struct device *dev)
374 {
375 	struct device_node *endpoint, *panel_node;
376 	struct device_node *np = dev->of_node;
377 	struct drm_panel *panel;
378 
379 	endpoint = of_graph_get_next_endpoint(np, NULL);
380 	if (!endpoint) {
381 		dev_err(dev, "no endpoint to fetch DPI panel\n");
382 		return NULL;
383 	}
384 
385 	/* don't proceed if we have an endpoint but no panel_node tied to it */
386 	panel_node = of_graph_get_remote_port_parent(endpoint);
387 	of_node_put(endpoint);
388 	if (!panel_node) {
389 		dev_err(dev, "no valid panel node\n");
390 		return NULL;
391 	}
392 
393 	panel = of_drm_find_panel(panel_node);
394 	of_node_put(panel_node);
395 
396 	return panel;
397 }
398 
399 static int vc4_dpi_bind(struct device *dev, struct device *master, void *data)
400 {
401 	struct platform_device *pdev = to_platform_device(dev);
402 	struct drm_device *drm = dev_get_drvdata(master);
403 	struct vc4_dev *vc4 = to_vc4_dev(drm);
404 	struct vc4_dpi *dpi;
405 	struct vc4_dpi_encoder *vc4_dpi_encoder;
406 	int ret;
407 
408 	dpi = devm_kzalloc(dev, sizeof(*dpi), GFP_KERNEL);
409 	if (!dpi)
410 		return -ENOMEM;
411 
412 	vc4_dpi_encoder = devm_kzalloc(dev, sizeof(*vc4_dpi_encoder),
413 				       GFP_KERNEL);
414 	if (!vc4_dpi_encoder)
415 		return -ENOMEM;
416 	vc4_dpi_encoder->base.type = VC4_ENCODER_TYPE_DPI;
417 	vc4_dpi_encoder->dpi = dpi;
418 	dpi->encoder = &vc4_dpi_encoder->base.base;
419 
420 	dpi->pdev = pdev;
421 	dpi->regs = vc4_ioremap_regs(pdev, 0);
422 	if (IS_ERR(dpi->regs))
423 		return PTR_ERR(dpi->regs);
424 
425 	vc4_dpi_dump_regs(dpi);
426 
427 	if (DPI_READ(DPI_ID) != DPI_ID_VALUE) {
428 		dev_err(dev, "Port returned 0x%08x for ID instead of 0x%08x\n",
429 			DPI_READ(DPI_ID), DPI_ID_VALUE);
430 		return -ENODEV;
431 	}
432 
433 	dpi->core_clock = devm_clk_get(dev, "core");
434 	if (IS_ERR(dpi->core_clock)) {
435 		ret = PTR_ERR(dpi->core_clock);
436 		if (ret != -EPROBE_DEFER)
437 			DRM_ERROR("Failed to get core clock: %d\n", ret);
438 		return ret;
439 	}
440 	dpi->pixel_clock = devm_clk_get(dev, "pixel");
441 	if (IS_ERR(dpi->pixel_clock)) {
442 		ret = PTR_ERR(dpi->pixel_clock);
443 		if (ret != -EPROBE_DEFER)
444 			DRM_ERROR("Failed to get pixel clock: %d\n", ret);
445 		return ret;
446 	}
447 
448 	ret = clk_prepare_enable(dpi->core_clock);
449 	if (ret)
450 		DRM_ERROR("Failed to turn on core clock: %d\n", ret);
451 
452 	dpi->panel = vc4_dpi_get_panel(dev);
453 
454 	drm_encoder_init(drm, dpi->encoder, &vc4_dpi_encoder_funcs,
455 			 DRM_MODE_ENCODER_DPI, NULL);
456 	drm_encoder_helper_add(dpi->encoder, &vc4_dpi_encoder_helper_funcs);
457 
458 	dpi->connector = vc4_dpi_connector_init(drm, dpi);
459 	if (IS_ERR(dpi->connector)) {
460 		ret = PTR_ERR(dpi->connector);
461 		goto err_destroy_encoder;
462 	}
463 
464 	if (dpi->panel)
465 		drm_panel_attach(dpi->panel, dpi->connector);
466 
467 	dev_set_drvdata(dev, dpi);
468 
469 	vc4->dpi = dpi;
470 
471 	return 0;
472 
473 err_destroy_encoder:
474 	drm_encoder_cleanup(dpi->encoder);
475 	clk_disable_unprepare(dpi->core_clock);
476 	return ret;
477 }
478 
479 static void vc4_dpi_unbind(struct device *dev, struct device *master,
480 			   void *data)
481 {
482 	struct drm_device *drm = dev_get_drvdata(master);
483 	struct vc4_dev *vc4 = to_vc4_dev(drm);
484 	struct vc4_dpi *dpi = dev_get_drvdata(dev);
485 
486 	if (dpi->panel)
487 		drm_panel_detach(dpi->panel);
488 
489 	vc4_dpi_connector_destroy(dpi->connector);
490 	drm_encoder_cleanup(dpi->encoder);
491 
492 	clk_disable_unprepare(dpi->core_clock);
493 
494 	vc4->dpi = NULL;
495 }
496 
497 static const struct component_ops vc4_dpi_ops = {
498 	.bind   = vc4_dpi_bind,
499 	.unbind = vc4_dpi_unbind,
500 };
501 
502 static int vc4_dpi_dev_probe(struct platform_device *pdev)
503 {
504 	return component_add(&pdev->dev, &vc4_dpi_ops);
505 }
506 
507 static int vc4_dpi_dev_remove(struct platform_device *pdev)
508 {
509 	component_del(&pdev->dev, &vc4_dpi_ops);
510 	return 0;
511 }
512 
513 struct platform_driver vc4_dpi_driver = {
514 	.probe = vc4_dpi_dev_probe,
515 	.remove = vc4_dpi_dev_remove,
516 	.driver = {
517 		.name = "vc4_dpi",
518 		.of_match_table = vc4_dpi_dt_match,
519 	},
520 };
521