1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (c) 2018, The Linux Foundation. All rights reserved.
4  */
5 
6 #include <linux/device.h>
7 #include <linux/delay.h>
8 #include <linux/gpio/consumer.h>
9 #include <linux/i2c.h>
10 #include <linux/media-bus-format.h>
11 #include <linux/regmap.h>
12 
13 #include <drm/drm_probe_helper.h>
14 #include <drm/drm_atomic_helper.h>
15 #include <drm/drm_edid.h>
16 #include <drm/drm_mipi_dsi.h>
17 #include <drm/drm_of.h>
18 
19 #include <video/videomode.h>
20 
21 #define I2C_MAIN 0
22 #define I2C_ADDR_MAIN 0x48
23 
24 #define I2C_CEC_DSI 1
25 #define I2C_ADDR_CEC_DSI 0x49
26 
27 #define I2C_MAX_IDX 2
28 
29 struct lt8912 {
30 	struct device *dev;
31 	struct drm_bridge bridge;
32 	struct drm_connector connector;
33 
34 	struct i2c_client *i2c_client[I2C_MAX_IDX];
35 	struct regmap *regmap[I2C_MAX_IDX];
36 
37 	struct device_node *host_node;
38 	struct drm_bridge *hdmi_port;
39 
40 	struct mipi_dsi_device *dsi;
41 
42 	struct gpio_desc *gp_reset;
43 
44 	struct videomode mode;
45 
46 	u8 data_lanes;
47 	bool is_power_on;
48 	bool is_attached;
49 };
50 
51 static int lt8912_write_init_config(struct lt8912 *lt)
52 {
53 	const struct reg_sequence seq[] = {
54 		/* Digital clock en*/
55 		{0x08, 0xff},
56 		{0x09, 0xff},
57 		{0x0a, 0xff},
58 		{0x0b, 0x7c},
59 		{0x0c, 0xff},
60 		{0x42, 0x04},
61 
62 		/*Tx Analog*/
63 		{0x31, 0xb1},
64 		{0x32, 0xb1},
65 		{0x33, 0x0e},
66 		{0x37, 0x00},
67 		{0x38, 0x22},
68 		{0x60, 0x82},
69 
70 		/*Cbus Analog*/
71 		{0x39, 0x45},
72 		{0x3a, 0x00},
73 		{0x3b, 0x00},
74 
75 		/*HDMI Pll Analog*/
76 		{0x44, 0x31},
77 		{0x55, 0x44},
78 		{0x57, 0x01},
79 		{0x5a, 0x02},
80 
81 		/*MIPI Analog*/
82 		{0x3e, 0xd6},
83 		{0x3f, 0xd4},
84 		{0x41, 0x3c},
85 		{0xB2, 0x00},
86 	};
87 
88 	return regmap_multi_reg_write(lt->regmap[I2C_MAIN], seq, ARRAY_SIZE(seq));
89 }
90 
91 static int lt8912_write_mipi_basic_config(struct lt8912 *lt)
92 {
93 	const struct reg_sequence seq[] = {
94 		{0x12, 0x04},
95 		{0x14, 0x00},
96 		{0x15, 0x00},
97 		{0x1a, 0x03},
98 		{0x1b, 0x03},
99 	};
100 
101 	return regmap_multi_reg_write(lt->regmap[I2C_CEC_DSI], seq, ARRAY_SIZE(seq));
102 };
103 
104 static int lt8912_write_dds_config(struct lt8912 *lt)
105 {
106 	const struct reg_sequence seq[] = {
107 		{0x4e, 0xff},
108 		{0x4f, 0x56},
109 		{0x50, 0x69},
110 		{0x51, 0x80},
111 		{0x1f, 0x5e},
112 		{0x20, 0x01},
113 		{0x21, 0x2c},
114 		{0x22, 0x01},
115 		{0x23, 0xfa},
116 		{0x24, 0x00},
117 		{0x25, 0xc8},
118 		{0x26, 0x00},
119 		{0x27, 0x5e},
120 		{0x28, 0x01},
121 		{0x29, 0x2c},
122 		{0x2a, 0x01},
123 		{0x2b, 0xfa},
124 		{0x2c, 0x00},
125 		{0x2d, 0xc8},
126 		{0x2e, 0x00},
127 		{0x42, 0x64},
128 		{0x43, 0x00},
129 		{0x44, 0x04},
130 		{0x45, 0x00},
131 		{0x46, 0x59},
132 		{0x47, 0x00},
133 		{0x48, 0xf2},
134 		{0x49, 0x06},
135 		{0x4a, 0x00},
136 		{0x4b, 0x72},
137 		{0x4c, 0x45},
138 		{0x4d, 0x00},
139 		{0x52, 0x08},
140 		{0x53, 0x00},
141 		{0x54, 0xb2},
142 		{0x55, 0x00},
143 		{0x56, 0xe4},
144 		{0x57, 0x0d},
145 		{0x58, 0x00},
146 		{0x59, 0xe4},
147 		{0x5a, 0x8a},
148 		{0x5b, 0x00},
149 		{0x5c, 0x34},
150 		{0x1e, 0x4f},
151 		{0x51, 0x00},
152 	};
153 
154 	return regmap_multi_reg_write(lt->regmap[I2C_CEC_DSI], seq, ARRAY_SIZE(seq));
155 }
156 
157 static int lt8912_write_rxlogicres_config(struct lt8912 *lt)
158 {
159 	int ret;
160 
161 	ret = regmap_write(lt->regmap[I2C_MAIN], 0x03, 0x7f);
162 	usleep_range(10000, 20000);
163 	ret |= regmap_write(lt->regmap[I2C_MAIN], 0x03, 0xff);
164 
165 	return ret;
166 };
167 
168 /* enable LVDS output with some hardcoded configuration, not required for the HDMI output */
169 static int lt8912_write_lvds_config(struct lt8912 *lt)
170 {
171 	const struct reg_sequence seq[] = {
172 		// lvds power up
173 		{0x44, 0x30},
174 		{0x51, 0x05},
175 
176 		// core pll bypass
177 		{0x50, 0x24}, // cp=50uA
178 		{0x51, 0x2d}, // Pix_clk as reference, second order passive LPF PLL
179 		{0x52, 0x04}, // loopdiv=0, use second-order PLL
180 		{0x69, 0x0e}, // CP_PRESET_DIV_RATIO
181 		{0x69, 0x8e},
182 		{0x6a, 0x00},
183 		{0x6c, 0xb8}, // RGD_CP_SOFT_K_EN,RGD_CP_SOFT_K[13:8]
184 		{0x6b, 0x51},
185 
186 		{0x04, 0xfb}, // core pll reset
187 		{0x04, 0xff},
188 
189 		// scaler bypass
190 		{0x7f, 0x00}, // disable scaler
191 		{0xa8, 0x13}, // 0x13: JEIDA, 0x33: VESA
192 
193 		{0x02, 0xf7}, // lvds pll reset
194 		{0x02, 0xff},
195 		{0x03, 0xcf},
196 		{0x03, 0xff},
197 	};
198 
199 	return regmap_multi_reg_write(lt->regmap[I2C_MAIN], seq, ARRAY_SIZE(seq));
200 };
201 
202 static inline struct lt8912 *bridge_to_lt8912(struct drm_bridge *b)
203 {
204 	return container_of(b, struct lt8912, bridge);
205 }
206 
207 static inline struct lt8912 *connector_to_lt8912(struct drm_connector *c)
208 {
209 	return container_of(c, struct lt8912, connector);
210 }
211 
212 static const struct regmap_config lt8912_regmap_config = {
213 	.reg_bits = 8,
214 	.val_bits = 8,
215 	.max_register = 0xff,
216 };
217 
218 static int lt8912_init_i2c(struct lt8912 *lt, struct i2c_client *client)
219 {
220 	unsigned int i;
221 	/*
222 	 * At this time we only initialize 2 chips, but the lt8912 provides
223 	 * a third interface for the audio over HDMI configuration.
224 	 */
225 	struct i2c_board_info info[] = {
226 		{ I2C_BOARD_INFO("lt8912p0", I2C_ADDR_MAIN), },
227 		{ I2C_BOARD_INFO("lt8912p1", I2C_ADDR_CEC_DSI), },
228 	};
229 
230 	if (!lt)
231 		return -ENODEV;
232 
233 	for (i = 0; i < ARRAY_SIZE(info); i++) {
234 		if (i > 0) {
235 			lt->i2c_client[i] = i2c_new_dummy_device(client->adapter,
236 								 info[i].addr);
237 			if (IS_ERR(lt->i2c_client[i]))
238 				return PTR_ERR(lt->i2c_client[i]);
239 		}
240 
241 		lt->regmap[i] = devm_regmap_init_i2c(lt->i2c_client[i],
242 						     &lt8912_regmap_config);
243 		if (IS_ERR(lt->regmap[i]))
244 			return PTR_ERR(lt->regmap[i]);
245 	}
246 	return 0;
247 }
248 
249 static int lt8912_free_i2c(struct lt8912 *lt)
250 {
251 	unsigned int i;
252 
253 	for (i = 1; i < I2C_MAX_IDX; i++)
254 		i2c_unregister_device(lt->i2c_client[i]);
255 
256 	return 0;
257 }
258 
259 static int lt8912_hard_power_on(struct lt8912 *lt)
260 {
261 	gpiod_set_value_cansleep(lt->gp_reset, 0);
262 	msleep(20);
263 
264 	return 0;
265 }
266 
267 static void lt8912_hard_power_off(struct lt8912 *lt)
268 {
269 	gpiod_set_value_cansleep(lt->gp_reset, 1);
270 	msleep(20);
271 	lt->is_power_on = false;
272 }
273 
274 static int lt8912_video_setup(struct lt8912 *lt)
275 {
276 	u32 hactive, h_total, hpw, hfp, hbp;
277 	u32 vactive, v_total, vpw, vfp, vbp;
278 	u8 settle = 0x08;
279 	int ret, hsync_activehigh, vsync_activehigh;
280 
281 	if (!lt)
282 		return -EINVAL;
283 
284 	hactive = lt->mode.hactive;
285 	hfp = lt->mode.hfront_porch;
286 	hpw = lt->mode.hsync_len;
287 	hbp = lt->mode.hback_porch;
288 	h_total = hactive + hfp + hpw + hbp;
289 	hsync_activehigh = lt->mode.flags & DISPLAY_FLAGS_HSYNC_HIGH;
290 
291 	vactive = lt->mode.vactive;
292 	vfp = lt->mode.vfront_porch;
293 	vpw = lt->mode.vsync_len;
294 	vbp = lt->mode.vback_porch;
295 	v_total = vactive + vfp + vpw + vbp;
296 	vsync_activehigh = lt->mode.flags & DISPLAY_FLAGS_VSYNC_HIGH;
297 
298 	if (vactive <= 600)
299 		settle = 0x04;
300 	else if (vactive == 1080)
301 		settle = 0x0a;
302 
303 	ret = regmap_write(lt->regmap[I2C_CEC_DSI], 0x10, 0x01);
304 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x11, settle);
305 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x18, hpw);
306 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x19, vpw);
307 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x1c, hactive & 0xff);
308 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x1d, hactive >> 8);
309 
310 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x2f, 0x0c);
311 
312 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x34, h_total & 0xff);
313 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x35, h_total >> 8);
314 
315 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x36, v_total & 0xff);
316 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x37, v_total >> 8);
317 
318 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x38, vbp & 0xff);
319 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x39, vbp >> 8);
320 
321 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x3a, vfp & 0xff);
322 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x3b, vfp >> 8);
323 
324 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x3c, hbp & 0xff);
325 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x3d, hbp >> 8);
326 
327 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x3e, hfp & 0xff);
328 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x3f, hfp >> 8);
329 
330 	ret |= regmap_update_bits(lt->regmap[I2C_MAIN], 0xab, BIT(0),
331 				  vsync_activehigh ? BIT(0) : 0);
332 	ret |= regmap_update_bits(lt->regmap[I2C_MAIN], 0xab, BIT(1),
333 				  hsync_activehigh ? BIT(1) : 0);
334 	ret |= regmap_update_bits(lt->regmap[I2C_MAIN], 0xb2, BIT(0),
335 				  lt->connector.display_info.is_hdmi ? BIT(0) : 0);
336 
337 	return ret;
338 }
339 
340 static int lt8912_soft_power_on(struct lt8912 *lt)
341 {
342 	if (!lt->is_power_on) {
343 		u32 lanes = lt->data_lanes;
344 
345 		lt8912_write_init_config(lt);
346 		regmap_write(lt->regmap[I2C_CEC_DSI], 0x13, lanes & 3);
347 
348 		lt8912_write_mipi_basic_config(lt);
349 
350 		lt->is_power_on = true;
351 	}
352 
353 	return 0;
354 }
355 
356 static int lt8912_video_on(struct lt8912 *lt)
357 {
358 	int ret;
359 
360 	ret = lt8912_video_setup(lt);
361 	if (ret < 0)
362 		goto end;
363 
364 	ret = lt8912_write_dds_config(lt);
365 	if (ret < 0)
366 		goto end;
367 
368 	ret = lt8912_write_rxlogicres_config(lt);
369 	if (ret < 0)
370 		goto end;
371 
372 	ret = lt8912_write_lvds_config(lt);
373 	if (ret < 0)
374 		goto end;
375 
376 end:
377 	return ret;
378 }
379 
380 static enum drm_connector_status lt8912_check_cable_status(struct lt8912 *lt)
381 {
382 	int ret;
383 	unsigned int reg_val;
384 
385 	ret = regmap_read(lt->regmap[I2C_MAIN], 0xC1, &reg_val);
386 	if (ret)
387 		return connector_status_unknown;
388 
389 	if (reg_val & BIT(7))
390 		return connector_status_connected;
391 
392 	return connector_status_disconnected;
393 }
394 
395 static enum drm_connector_status
396 lt8912_connector_detect(struct drm_connector *connector, bool force)
397 {
398 	struct lt8912 *lt = connector_to_lt8912(connector);
399 
400 	if (lt->hdmi_port->ops & DRM_BRIDGE_OP_DETECT)
401 		return drm_bridge_detect(lt->hdmi_port);
402 
403 	return lt8912_check_cable_status(lt);
404 }
405 
406 static const struct drm_connector_funcs lt8912_connector_funcs = {
407 	.detect = lt8912_connector_detect,
408 	.fill_modes = drm_helper_probe_single_connector_modes,
409 	.destroy = drm_connector_cleanup,
410 	.reset = drm_atomic_helper_connector_reset,
411 	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
412 	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
413 };
414 
415 static enum drm_mode_status
416 lt8912_connector_mode_valid(struct drm_connector *connector,
417 			    struct drm_display_mode *mode)
418 {
419 	if (mode->clock > 150000)
420 		return MODE_CLOCK_HIGH;
421 
422 	if (mode->hdisplay > 1920)
423 		return MODE_BAD_HVALUE;
424 
425 	if (mode->vdisplay > 1080)
426 		return MODE_BAD_VVALUE;
427 
428 	return MODE_OK;
429 }
430 
431 static int lt8912_connector_get_modes(struct drm_connector *connector)
432 {
433 	struct edid *edid;
434 	int ret = -1;
435 	int num = 0;
436 	struct lt8912 *lt = connector_to_lt8912(connector);
437 	u32 bus_format = MEDIA_BUS_FMT_RGB888_1X24;
438 
439 	edid = drm_bridge_get_edid(lt->hdmi_port, connector);
440 	if (edid) {
441 		drm_connector_update_edid_property(connector, edid);
442 		num = drm_add_edid_modes(connector, edid);
443 	} else {
444 		return ret;
445 	}
446 
447 	ret = drm_display_info_set_bus_formats(&connector->display_info,
448 					       &bus_format, 1);
449 	if (ret)
450 		num = ret;
451 
452 	kfree(edid);
453 	return num;
454 }
455 
456 static const struct drm_connector_helper_funcs lt8912_connector_helper_funcs = {
457 	.get_modes = lt8912_connector_get_modes,
458 	.mode_valid = lt8912_connector_mode_valid,
459 };
460 
461 static void lt8912_bridge_mode_set(struct drm_bridge *bridge,
462 				   const struct drm_display_mode *mode,
463 				   const struct drm_display_mode *adj)
464 {
465 	struct lt8912 *lt = bridge_to_lt8912(bridge);
466 
467 	drm_display_mode_to_videomode(adj, &lt->mode);
468 }
469 
470 static void lt8912_bridge_enable(struct drm_bridge *bridge)
471 {
472 	struct lt8912 *lt = bridge_to_lt8912(bridge);
473 
474 	lt8912_video_on(lt);
475 }
476 
477 static int lt8912_attach_dsi(struct lt8912 *lt)
478 {
479 	struct device *dev = lt->dev;
480 	struct mipi_dsi_host *host;
481 	struct mipi_dsi_device *dsi;
482 	int ret = -1;
483 	const struct mipi_dsi_device_info info = { .type = "lt8912",
484 						   .channel = 0,
485 						   .node = NULL,
486 						 };
487 
488 	host = of_find_mipi_dsi_host_by_node(lt->host_node);
489 	if (!host) {
490 		dev_err(dev, "failed to find dsi host\n");
491 		return -EPROBE_DEFER;
492 	}
493 
494 	dsi = devm_mipi_dsi_device_register_full(dev, host, &info);
495 	if (IS_ERR(dsi)) {
496 		ret = PTR_ERR(dsi);
497 		dev_err(dev, "failed to create dsi device (%d)\n", ret);
498 		return ret;
499 	}
500 
501 	lt->dsi = dsi;
502 
503 	dsi->lanes = lt->data_lanes;
504 	dsi->format = MIPI_DSI_FMT_RGB888;
505 
506 	dsi->mode_flags = MIPI_DSI_MODE_VIDEO |
507 			  MIPI_DSI_MODE_VIDEO_BURST |
508 			  MIPI_DSI_MODE_LPM |
509 			  MIPI_DSI_MODE_NO_EOT_PACKET;
510 
511 	ret = devm_mipi_dsi_attach(dev, dsi);
512 	if (ret < 0) {
513 		dev_err(dev, "failed to attach dsi to host\n");
514 		return ret;
515 	}
516 
517 	return 0;
518 }
519 
520 static int lt8912_bridge_connector_init(struct drm_bridge *bridge)
521 {
522 	int ret;
523 	struct lt8912 *lt = bridge_to_lt8912(bridge);
524 	struct drm_connector *connector = &lt->connector;
525 
526 	connector->polled = DRM_CONNECTOR_POLL_CONNECT |
527 			    DRM_CONNECTOR_POLL_DISCONNECT;
528 
529 	ret = drm_connector_init(bridge->dev, connector,
530 				 &lt8912_connector_funcs,
531 				 lt->hdmi_port->type);
532 	if (ret)
533 		goto exit;
534 
535 	drm_connector_helper_add(connector, &lt8912_connector_helper_funcs);
536 
537 	connector->dpms = DRM_MODE_DPMS_OFF;
538 	drm_connector_attach_encoder(connector, bridge->encoder);
539 
540 exit:
541 	return ret;
542 }
543 
544 static int lt8912_bridge_attach(struct drm_bridge *bridge,
545 				enum drm_bridge_attach_flags flags)
546 {
547 	struct lt8912 *lt = bridge_to_lt8912(bridge);
548 	int ret;
549 
550 	if (!(flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)) {
551 		ret = lt8912_bridge_connector_init(bridge);
552 		if (ret) {
553 			dev_err(lt->dev, "Failed to init bridge ! (%d)\n", ret);
554 			return ret;
555 		}
556 	}
557 
558 	ret = lt8912_hard_power_on(lt);
559 	if (ret)
560 		return ret;
561 
562 	ret = lt8912_soft_power_on(lt);
563 	if (ret)
564 		goto error;
565 
566 	lt->is_attached = true;
567 
568 	return 0;
569 
570 error:
571 	lt8912_hard_power_off(lt);
572 	return ret;
573 }
574 
575 static void lt8912_bridge_detach(struct drm_bridge *bridge)
576 {
577 	struct lt8912 *lt = bridge_to_lt8912(bridge);
578 
579 	if (lt->is_attached) {
580 		lt8912_hard_power_off(lt);
581 		drm_connector_unregister(&lt->connector);
582 		drm_connector_cleanup(&lt->connector);
583 	}
584 }
585 
586 static enum drm_connector_status
587 lt8912_bridge_detect(struct drm_bridge *bridge)
588 {
589 	struct lt8912 *lt = bridge_to_lt8912(bridge);
590 
591 	if (lt->hdmi_port->ops & DRM_BRIDGE_OP_DETECT)
592 		return drm_bridge_detect(lt->hdmi_port);
593 
594 	return lt8912_check_cable_status(lt);
595 }
596 
597 static struct edid *lt8912_bridge_get_edid(struct drm_bridge *bridge,
598 					   struct drm_connector *connector)
599 {
600 	struct lt8912 *lt = bridge_to_lt8912(bridge);
601 
602 	/*
603 	 * edid must be read through the ddc bus but it must be
604 	 * given to the hdmi connector node.
605 	 */
606 	if (lt->hdmi_port->ops & DRM_BRIDGE_OP_EDID)
607 		return drm_bridge_get_edid(lt->hdmi_port, connector);
608 
609 	dev_warn(lt->dev, "The connected bridge does not supports DRM_BRIDGE_OP_EDID\n");
610 	return NULL;
611 }
612 
613 static const struct drm_bridge_funcs lt8912_bridge_funcs = {
614 	.attach = lt8912_bridge_attach,
615 	.detach = lt8912_bridge_detach,
616 	.mode_set = lt8912_bridge_mode_set,
617 	.enable = lt8912_bridge_enable,
618 	.detect = lt8912_bridge_detect,
619 	.get_edid = lt8912_bridge_get_edid,
620 };
621 
622 static int lt8912_parse_dt(struct lt8912 *lt)
623 {
624 	struct gpio_desc *gp_reset;
625 	struct device *dev = lt->dev;
626 	int ret;
627 	int data_lanes;
628 	struct device_node *port_node;
629 
630 	gp_reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
631 	if (IS_ERR(gp_reset)) {
632 		ret = PTR_ERR(gp_reset);
633 		if (ret != -EPROBE_DEFER)
634 			dev_err(dev, "Failed to get reset gpio: %d\n", ret);
635 		return ret;
636 	}
637 	lt->gp_reset = gp_reset;
638 
639 	data_lanes = drm_of_get_data_lanes_count_ep(dev->of_node, 0, -1, 1, 4);
640 	if (data_lanes < 0) {
641 		dev_err(lt->dev, "%s: Bad data-lanes property\n", __func__);
642 		return data_lanes;
643 	}
644 
645 	lt->data_lanes = data_lanes;
646 
647 	lt->host_node = of_graph_get_remote_node(dev->of_node, 0, -1);
648 	if (!lt->host_node) {
649 		dev_err(lt->dev, "%s: Failed to get remote port\n", __func__);
650 		return -ENODEV;
651 	}
652 
653 	port_node = of_graph_get_remote_node(dev->of_node, 1, -1);
654 	if (!port_node) {
655 		dev_err(lt->dev, "%s: Failed to get connector port\n", __func__);
656 		ret = -ENODEV;
657 		goto err_free_host_node;
658 	}
659 
660 	lt->hdmi_port = of_drm_find_bridge(port_node);
661 	if (!lt->hdmi_port) {
662 		dev_err(lt->dev, "%s: Failed to get hdmi port\n", __func__);
663 		ret = -ENODEV;
664 		goto err_free_host_node;
665 	}
666 
667 	if (!of_device_is_compatible(port_node, "hdmi-connector")) {
668 		dev_err(lt->dev, "%s: Failed to get hdmi port\n", __func__);
669 		ret = -EINVAL;
670 		goto err_free_host_node;
671 	}
672 
673 	of_node_put(port_node);
674 	return 0;
675 
676 err_free_host_node:
677 	of_node_put(port_node);
678 	of_node_put(lt->host_node);
679 	return ret;
680 }
681 
682 static int lt8912_put_dt(struct lt8912 *lt)
683 {
684 	of_node_put(lt->host_node);
685 	return 0;
686 }
687 
688 static int lt8912_probe(struct i2c_client *client,
689 			const struct i2c_device_id *id)
690 {
691 	static struct lt8912 *lt;
692 	int ret = 0;
693 	struct device *dev = &client->dev;
694 
695 	lt = devm_kzalloc(dev, sizeof(struct lt8912), GFP_KERNEL);
696 	if (!lt)
697 		return -ENOMEM;
698 
699 	lt->dev = dev;
700 	lt->i2c_client[0] = client;
701 
702 	ret = lt8912_parse_dt(lt);
703 	if (ret)
704 		goto err_dt_parse;
705 
706 	ret = lt8912_init_i2c(lt, client);
707 	if (ret)
708 		goto err_i2c;
709 
710 	i2c_set_clientdata(client, lt);
711 
712 	lt->bridge.funcs = &lt8912_bridge_funcs;
713 	lt->bridge.of_node = dev->of_node;
714 	lt->bridge.ops = (DRM_BRIDGE_OP_EDID |
715 			  DRM_BRIDGE_OP_DETECT);
716 
717 	drm_bridge_add(&lt->bridge);
718 
719 	ret = lt8912_attach_dsi(lt);
720 	if (ret)
721 		goto err_attach;
722 
723 	return 0;
724 
725 err_attach:
726 	drm_bridge_remove(&lt->bridge);
727 	lt8912_free_i2c(lt);
728 err_i2c:
729 	lt8912_put_dt(lt);
730 err_dt_parse:
731 	return ret;
732 }
733 
734 static void lt8912_remove(struct i2c_client *client)
735 {
736 	struct lt8912 *lt = i2c_get_clientdata(client);
737 
738 	lt8912_bridge_detach(&lt->bridge);
739 	drm_bridge_remove(&lt->bridge);
740 	lt8912_free_i2c(lt);
741 	lt8912_put_dt(lt);
742 }
743 
744 static const struct of_device_id lt8912_dt_match[] = {
745 	{.compatible = "lontium,lt8912b"},
746 	{}
747 };
748 MODULE_DEVICE_TABLE(of, lt8912_dt_match);
749 
750 static const struct i2c_device_id lt8912_id[] = {
751 	{"lt8912", 0},
752 	{},
753 };
754 MODULE_DEVICE_TABLE(i2c, lt8912_id);
755 
756 static struct i2c_driver lt8912_i2c_driver = {
757 	.driver = {
758 		.name = "lt8912",
759 		.of_match_table = lt8912_dt_match,
760 	},
761 	.probe = lt8912_probe,
762 	.remove = lt8912_remove,
763 	.id_table = lt8912_id,
764 };
765 module_i2c_driver(lt8912_i2c_driver);
766 
767 MODULE_AUTHOR("Adrien Grassein <adrien.grassein@gmail.com>");
768 MODULE_DESCRIPTION("lt8912 drm driver");
769 MODULE_LICENSE("GPL v2");
770