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/regmap.h>
11 
12 #include <drm/drm_probe_helper.h>
13 #include <drm/drm_atomic_helper.h>
14 #include <drm/drm_mipi_dsi.h>
15 #include <drm/drm_of.h>
16 
17 #include <video/videomode.h>
18 
19 #define I2C_MAIN 0
20 #define I2C_ADDR_MAIN 0x48
21 
22 #define I2C_CEC_DSI 1
23 #define I2C_ADDR_CEC_DSI 0x49
24 
25 #define I2C_MAX_IDX 2
26 
27 struct lt8912 {
28 	struct device *dev;
29 	struct drm_bridge bridge;
30 	struct drm_connector connector;
31 
32 	struct i2c_client *i2c_client[I2C_MAX_IDX];
33 	struct regmap *regmap[I2C_MAX_IDX];
34 
35 	struct device_node *host_node;
36 	struct drm_bridge *hdmi_port;
37 
38 	struct mipi_dsi_device *dsi;
39 
40 	struct gpio_desc *gp_reset;
41 
42 	struct videomode mode;
43 
44 	u8 data_lanes;
45 	bool is_power_on;
46 	bool is_attached;
47 };
48 
49 static int lt8912_write_init_config(struct lt8912 *lt)
50 {
51 	const struct reg_sequence seq[] = {
52 		/* Digital clock en*/
53 		{0x08, 0xff},
54 		{0x09, 0xff},
55 		{0x0a, 0xff},
56 		{0x0b, 0x7c},
57 		{0x0c, 0xff},
58 		{0x42, 0x04},
59 
60 		/*Tx Analog*/
61 		{0x31, 0xb1},
62 		{0x32, 0xb1},
63 		{0x33, 0x0e},
64 		{0x37, 0x00},
65 		{0x38, 0x22},
66 		{0x60, 0x82},
67 
68 		/*Cbus Analog*/
69 		{0x39, 0x45},
70 		{0x3a, 0x00},
71 		{0x3b, 0x00},
72 
73 		/*HDMI Pll Analog*/
74 		{0x44, 0x31},
75 		{0x55, 0x44},
76 		{0x57, 0x01},
77 		{0x5a, 0x02},
78 
79 		/*MIPI Analog*/
80 		{0x3e, 0xd6},
81 		{0x3f, 0xd4},
82 		{0x41, 0x3c},
83 		{0xB2, 0x00},
84 	};
85 
86 	return regmap_multi_reg_write(lt->regmap[I2C_MAIN], seq, ARRAY_SIZE(seq));
87 }
88 
89 static int lt8912_write_mipi_basic_config(struct lt8912 *lt)
90 {
91 	const struct reg_sequence seq[] = {
92 		{0x12, 0x04},
93 		{0x14, 0x00},
94 		{0x15, 0x00},
95 		{0x1a, 0x03},
96 		{0x1b, 0x03},
97 	};
98 
99 	return regmap_multi_reg_write(lt->regmap[I2C_CEC_DSI], seq, ARRAY_SIZE(seq));
100 };
101 
102 static int lt8912_write_dds_config(struct lt8912 *lt)
103 {
104 	const struct reg_sequence seq[] = {
105 		{0x4e, 0xff},
106 		{0x4f, 0x56},
107 		{0x50, 0x69},
108 		{0x51, 0x80},
109 		{0x1f, 0x5e},
110 		{0x20, 0x01},
111 		{0x21, 0x2c},
112 		{0x22, 0x01},
113 		{0x23, 0xfa},
114 		{0x24, 0x00},
115 		{0x25, 0xc8},
116 		{0x26, 0x00},
117 		{0x27, 0x5e},
118 		{0x28, 0x01},
119 		{0x29, 0x2c},
120 		{0x2a, 0x01},
121 		{0x2b, 0xfa},
122 		{0x2c, 0x00},
123 		{0x2d, 0xc8},
124 		{0x2e, 0x00},
125 		{0x42, 0x64},
126 		{0x43, 0x00},
127 		{0x44, 0x04},
128 		{0x45, 0x00},
129 		{0x46, 0x59},
130 		{0x47, 0x00},
131 		{0x48, 0xf2},
132 		{0x49, 0x06},
133 		{0x4a, 0x00},
134 		{0x4b, 0x72},
135 		{0x4c, 0x45},
136 		{0x4d, 0x00},
137 		{0x52, 0x08},
138 		{0x53, 0x00},
139 		{0x54, 0xb2},
140 		{0x55, 0x00},
141 		{0x56, 0xe4},
142 		{0x57, 0x0d},
143 		{0x58, 0x00},
144 		{0x59, 0xe4},
145 		{0x5a, 0x8a},
146 		{0x5b, 0x00},
147 		{0x5c, 0x34},
148 		{0x1e, 0x4f},
149 		{0x51, 0x00},
150 	};
151 
152 	return regmap_multi_reg_write(lt->regmap[I2C_CEC_DSI], seq, ARRAY_SIZE(seq));
153 }
154 
155 static int lt8912_write_rxlogicres_config(struct lt8912 *lt)
156 {
157 	int ret;
158 
159 	ret = regmap_write(lt->regmap[I2C_MAIN], 0x03, 0x7f);
160 	usleep_range(10000, 20000);
161 	ret |= regmap_write(lt->regmap[I2C_MAIN], 0x03, 0xff);
162 
163 	return ret;
164 };
165 
166 static int lt8912_write_lvds_config(struct lt8912 *lt)
167 {
168 	const struct reg_sequence seq[] = {
169 		{0x44, 0x30},
170 		{0x51, 0x05},
171 		{0x50, 0x24},
172 		{0x51, 0x2d},
173 		{0x52, 0x04},
174 		{0x69, 0x0e},
175 		{0x69, 0x8e},
176 		{0x6a, 0x00},
177 		{0x6c, 0xb8},
178 		{0x6b, 0x51},
179 		{0x04, 0xfb},
180 		{0x04, 0xff},
181 		{0x7f, 0x00},
182 		{0xa8, 0x13},
183 		{0x02, 0xf7},
184 		{0x02, 0xff},
185 		{0x03, 0xcf},
186 		{0x03, 0xff},
187 	};
188 
189 	return regmap_multi_reg_write(lt->regmap[I2C_CEC_DSI], seq, ARRAY_SIZE(seq));
190 };
191 
192 static inline struct lt8912 *bridge_to_lt8912(struct drm_bridge *b)
193 {
194 	return container_of(b, struct lt8912, bridge);
195 }
196 
197 static inline struct lt8912 *connector_to_lt8912(struct drm_connector *c)
198 {
199 	return container_of(c, struct lt8912, connector);
200 }
201 
202 static const struct regmap_config lt8912_regmap_config = {
203 	.reg_bits = 8,
204 	.val_bits = 8,
205 	.max_register = 0xff,
206 };
207 
208 static int lt8912_init_i2c(struct lt8912 *lt, struct i2c_client *client)
209 {
210 	unsigned int i;
211 	/*
212 	 * At this time we only initialize 2 chips, but the lt8912 provides
213 	 * a third interface for the audio over HDMI configuration.
214 	 */
215 	struct i2c_board_info info[] = {
216 		{ I2C_BOARD_INFO("lt8912p0", I2C_ADDR_MAIN), },
217 		{ I2C_BOARD_INFO("lt8912p1", I2C_ADDR_CEC_DSI), },
218 	};
219 
220 	if (!lt)
221 		return -ENODEV;
222 
223 	for (i = 0; i < ARRAY_SIZE(info); i++) {
224 		if (i > 0) {
225 			lt->i2c_client[i] = i2c_new_dummy_device(client->adapter,
226 								 info[i].addr);
227 			if (IS_ERR(lt->i2c_client[i]))
228 				return PTR_ERR(lt->i2c_client[i]);
229 		}
230 
231 		lt->regmap[i] = devm_regmap_init_i2c(lt->i2c_client[i],
232 						     &lt8912_regmap_config);
233 		if (IS_ERR(lt->regmap[i]))
234 			return PTR_ERR(lt->regmap[i]);
235 	}
236 	return 0;
237 }
238 
239 static int lt8912_free_i2c(struct lt8912 *lt)
240 {
241 	unsigned int i;
242 
243 	for (i = 1; i < I2C_MAX_IDX; i++)
244 		i2c_unregister_device(lt->i2c_client[i]);
245 
246 	return 0;
247 }
248 
249 static int lt8912_hard_power_on(struct lt8912 *lt)
250 {
251 	gpiod_set_value_cansleep(lt->gp_reset, 0);
252 	msleep(20);
253 
254 	return 0;
255 }
256 
257 static void lt8912_hard_power_off(struct lt8912 *lt)
258 {
259 	gpiod_set_value_cansleep(lt->gp_reset, 1);
260 	msleep(20);
261 	lt->is_power_on = false;
262 }
263 
264 static int lt8912_video_setup(struct lt8912 *lt)
265 {
266 	u32 hactive, h_total, hpw, hfp, hbp;
267 	u32 vactive, v_total, vpw, vfp, vbp;
268 	u8 settle = 0x08;
269 	int ret;
270 
271 	if (!lt)
272 		return -EINVAL;
273 
274 	hactive = lt->mode.hactive;
275 	hfp = lt->mode.hfront_porch;
276 	hpw = lt->mode.hsync_len;
277 	hbp = lt->mode.hback_porch;
278 	h_total = hactive + hfp + hpw + hbp;
279 
280 	vactive = lt->mode.vactive;
281 	vfp = lt->mode.vfront_porch;
282 	vpw = lt->mode.vsync_len;
283 	vbp = lt->mode.vback_porch;
284 	v_total = vactive + vfp + vpw + vbp;
285 
286 	if (vactive <= 600)
287 		settle = 0x04;
288 	else if (vactive == 1080)
289 		settle = 0x0a;
290 
291 	ret = regmap_write(lt->regmap[I2C_CEC_DSI], 0x10, 0x01);
292 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x11, settle);
293 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x18, hpw);
294 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x19, vpw);
295 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x1c, hactive & 0xff);
296 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x1d, hactive >> 8);
297 
298 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x2f, 0x0c);
299 
300 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x34, h_total & 0xff);
301 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x35, h_total >> 8);
302 
303 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x36, v_total & 0xff);
304 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x37, v_total >> 8);
305 
306 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x38, vbp & 0xff);
307 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x39, vbp >> 8);
308 
309 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x3a, vfp & 0xff);
310 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x3b, vfp >> 8);
311 
312 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x3c, hbp & 0xff);
313 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x3d, hbp >> 8);
314 
315 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x3e, hfp & 0xff);
316 	ret |= regmap_write(lt->regmap[I2C_CEC_DSI], 0x3f, hfp >> 8);
317 
318 	return ret;
319 }
320 
321 static int lt8912_soft_power_on(struct lt8912 *lt)
322 {
323 	if (!lt->is_power_on) {
324 		u32 lanes = lt->data_lanes;
325 
326 		lt8912_write_init_config(lt);
327 		regmap_write(lt->regmap[I2C_CEC_DSI], 0x13, lanes & 3);
328 
329 		lt8912_write_mipi_basic_config(lt);
330 
331 		lt->is_power_on = true;
332 	}
333 
334 	return 0;
335 }
336 
337 static int lt8912_video_on(struct lt8912 *lt)
338 {
339 	int ret;
340 
341 	ret = lt8912_video_setup(lt);
342 	if (ret < 0)
343 		goto end;
344 
345 	ret = lt8912_write_dds_config(lt);
346 	if (ret < 0)
347 		goto end;
348 
349 	ret = lt8912_write_rxlogicres_config(lt);
350 	if (ret < 0)
351 		goto end;
352 
353 	ret = lt8912_write_lvds_config(lt);
354 	if (ret < 0)
355 		goto end;
356 
357 end:
358 	return ret;
359 }
360 
361 static enum drm_connector_status lt8912_check_cable_status(struct lt8912 *lt)
362 {
363 	int ret;
364 	unsigned int reg_val;
365 
366 	ret = regmap_read(lt->regmap[I2C_MAIN], 0xC1, &reg_val);
367 	if (ret)
368 		return connector_status_unknown;
369 
370 	if (reg_val & BIT(7))
371 		return connector_status_connected;
372 
373 	return connector_status_disconnected;
374 }
375 
376 static enum drm_connector_status
377 lt8912_connector_detect(struct drm_connector *connector, bool force)
378 {
379 	struct lt8912 *lt = connector_to_lt8912(connector);
380 
381 	if (lt->hdmi_port->ops & DRM_BRIDGE_OP_DETECT)
382 		return drm_bridge_detect(lt->hdmi_port);
383 
384 	return lt8912_check_cable_status(lt);
385 }
386 
387 static const struct drm_connector_funcs lt8912_connector_funcs = {
388 	.detect = lt8912_connector_detect,
389 	.fill_modes = drm_helper_probe_single_connector_modes,
390 	.destroy = drm_connector_cleanup,
391 	.reset = drm_atomic_helper_connector_reset,
392 	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
393 	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
394 };
395 
396 static enum drm_mode_status
397 lt8912_connector_mode_valid(struct drm_connector *connector,
398 			    struct drm_display_mode *mode)
399 {
400 	if (mode->clock > 150000)
401 		return MODE_CLOCK_HIGH;
402 
403 	if (mode->hdisplay > 1920)
404 		return MODE_BAD_HVALUE;
405 
406 	if (mode->vdisplay > 1080)
407 		return MODE_BAD_VVALUE;
408 
409 	return MODE_OK;
410 }
411 
412 static int lt8912_connector_get_modes(struct drm_connector *connector)
413 {
414 	struct edid *edid;
415 	int ret = -1;
416 	int num = 0;
417 	struct lt8912 *lt = connector_to_lt8912(connector);
418 	u32 bus_format = MEDIA_BUS_FMT_RGB888_1X24;
419 
420 	edid = drm_bridge_get_edid(lt->hdmi_port, connector);
421 	if (edid) {
422 		drm_connector_update_edid_property(connector, edid);
423 		num = drm_add_edid_modes(connector, edid);
424 	} else {
425 		return ret;
426 	}
427 
428 	ret = drm_display_info_set_bus_formats(&connector->display_info,
429 					       &bus_format, 1);
430 	if (ret)
431 		num = ret;
432 
433 	kfree(edid);
434 	return num;
435 }
436 
437 static const struct drm_connector_helper_funcs lt8912_connector_helper_funcs = {
438 	.get_modes = lt8912_connector_get_modes,
439 	.mode_valid = lt8912_connector_mode_valid,
440 };
441 
442 static void lt8912_bridge_mode_set(struct drm_bridge *bridge,
443 				   const struct drm_display_mode *mode,
444 				   const struct drm_display_mode *adj)
445 {
446 	struct lt8912 *lt = bridge_to_lt8912(bridge);
447 
448 	drm_display_mode_to_videomode(adj, &lt->mode);
449 }
450 
451 static void lt8912_bridge_enable(struct drm_bridge *bridge)
452 {
453 	struct lt8912 *lt = bridge_to_lt8912(bridge);
454 
455 	lt8912_video_on(lt);
456 }
457 
458 static int lt8912_attach_dsi(struct lt8912 *lt)
459 {
460 	struct device *dev = lt->dev;
461 	struct mipi_dsi_host *host;
462 	struct mipi_dsi_device *dsi;
463 	int ret = -1;
464 	const struct mipi_dsi_device_info info = { .type = "lt8912",
465 						   .channel = 0,
466 						   .node = NULL,
467 						 };
468 
469 	host = of_find_mipi_dsi_host_by_node(lt->host_node);
470 	if (!host) {
471 		dev_err(dev, "failed to find dsi host\n");
472 		return -EPROBE_DEFER;
473 	}
474 
475 	dsi = mipi_dsi_device_register_full(host, &info);
476 	if (IS_ERR(dsi)) {
477 		ret = PTR_ERR(dsi);
478 		dev_err(dev, "failed to create dsi device (%d)\n", ret);
479 		goto err_dsi_device;
480 	}
481 
482 	lt->dsi = dsi;
483 
484 	dsi->lanes = lt->data_lanes;
485 	dsi->format = MIPI_DSI_FMT_RGB888;
486 
487 	dsi->mode_flags = MIPI_DSI_MODE_VIDEO |
488 			  MIPI_DSI_MODE_VIDEO_BURST |
489 			  MIPI_DSI_MODE_LPM |
490 			  MIPI_DSI_MODE_NO_EOT_PACKET;
491 
492 	ret = mipi_dsi_attach(dsi);
493 	if (ret < 0) {
494 		dev_err(dev, "failed to attach dsi to host\n");
495 		goto err_dsi_attach;
496 	}
497 
498 	return 0;
499 
500 err_dsi_attach:
501 	mipi_dsi_device_unregister(dsi);
502 err_dsi_device:
503 	return ret;
504 }
505 
506 static void lt8912_detach_dsi(struct lt8912 *lt)
507 {
508 	mipi_dsi_detach(lt->dsi);
509 	mipi_dsi_device_unregister(lt->dsi);
510 }
511 
512 static int lt8912_bridge_connector_init(struct drm_bridge *bridge)
513 {
514 	int ret;
515 	struct lt8912 *lt = bridge_to_lt8912(bridge);
516 	struct drm_connector *connector = &lt->connector;
517 
518 	connector->polled = DRM_CONNECTOR_POLL_CONNECT |
519 			    DRM_CONNECTOR_POLL_DISCONNECT;
520 
521 	ret = drm_connector_init(bridge->dev, connector,
522 				 &lt8912_connector_funcs,
523 				 lt->hdmi_port->type);
524 	if (ret)
525 		goto exit;
526 
527 	drm_connector_helper_add(connector, &lt8912_connector_helper_funcs);
528 
529 	connector->dpms = DRM_MODE_DPMS_OFF;
530 	drm_connector_attach_encoder(connector, bridge->encoder);
531 
532 exit:
533 	return ret;
534 }
535 
536 static int lt8912_bridge_attach(struct drm_bridge *bridge,
537 				enum drm_bridge_attach_flags flags)
538 {
539 	struct lt8912 *lt = bridge_to_lt8912(bridge);
540 	int ret;
541 
542 	if (!(flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)) {
543 		ret = lt8912_bridge_connector_init(bridge);
544 		if (ret) {
545 			dev_err(lt->dev, "Failed to init bridge ! (%d)\n", ret);
546 			return ret;
547 		}
548 	}
549 
550 	ret = lt8912_hard_power_on(lt);
551 	if (ret)
552 		return ret;
553 
554 	ret = lt8912_soft_power_on(lt);
555 	if (ret)
556 		goto error;
557 
558 	ret = lt8912_attach_dsi(lt);
559 	if (ret)
560 		goto error;
561 
562 	lt->is_attached = true;
563 
564 	return 0;
565 
566 error:
567 	lt8912_hard_power_off(lt);
568 	return ret;
569 }
570 
571 static void lt8912_bridge_detach(struct drm_bridge *bridge)
572 {
573 	struct lt8912 *lt = bridge_to_lt8912(bridge);
574 
575 	if (lt->is_attached) {
576 		lt8912_detach_dsi(lt);
577 		lt8912_hard_power_off(lt);
578 		drm_connector_unregister(&lt->connector);
579 		drm_connector_cleanup(&lt->connector);
580 	}
581 }
582 
583 static enum drm_connector_status
584 lt8912_bridge_detect(struct drm_bridge *bridge)
585 {
586 	struct lt8912 *lt = bridge_to_lt8912(bridge);
587 
588 	if (lt->hdmi_port->ops & DRM_BRIDGE_OP_DETECT)
589 		return drm_bridge_detect(lt->hdmi_port);
590 
591 	return lt8912_check_cable_status(lt);
592 }
593 
594 static struct edid *lt8912_bridge_get_edid(struct drm_bridge *bridge,
595 					   struct drm_connector *connector)
596 {
597 	struct lt8912 *lt = bridge_to_lt8912(bridge);
598 
599 	/*
600 	 * edid must be read through the ddc bus but it must be
601 	 * given to the hdmi connector node.
602 	 */
603 	if (lt->hdmi_port->ops & DRM_BRIDGE_OP_EDID)
604 		return drm_bridge_get_edid(lt->hdmi_port, connector);
605 
606 	dev_warn(lt->dev, "The connected bridge does not supports DRM_BRIDGE_OP_EDID\n");
607 	return NULL;
608 }
609 
610 static const struct drm_bridge_funcs lt8912_bridge_funcs = {
611 	.attach = lt8912_bridge_attach,
612 	.detach = lt8912_bridge_detach,
613 	.mode_set = lt8912_bridge_mode_set,
614 	.enable = lt8912_bridge_enable,
615 	.detect = lt8912_bridge_detect,
616 	.get_edid = lt8912_bridge_get_edid,
617 };
618 
619 static int lt8912_parse_dt(struct lt8912 *lt)
620 {
621 	struct gpio_desc *gp_reset;
622 	struct device *dev = lt->dev;
623 	int ret;
624 	int data_lanes;
625 	struct device_node *port_node;
626 	struct device_node *endpoint;
627 
628 	gp_reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
629 	if (IS_ERR(gp_reset)) {
630 		ret = PTR_ERR(gp_reset);
631 		if (ret != -EPROBE_DEFER)
632 			dev_err(dev, "Failed to get reset gpio: %d\n", ret);
633 		return ret;
634 	}
635 	lt->gp_reset = gp_reset;
636 
637 	endpoint = of_graph_get_endpoint_by_regs(dev->of_node, 0, -1);
638 	if (!endpoint)
639 		return -ENODEV;
640 
641 	data_lanes = of_property_count_u32_elems(endpoint, "data-lanes");
642 	of_node_put(endpoint);
643 	if (data_lanes < 0) {
644 		dev_err(lt->dev, "%s: Bad data-lanes property\n", __func__);
645 		return data_lanes;
646 	}
647 	lt->data_lanes = data_lanes;
648 
649 	lt->host_node = of_graph_get_remote_node(dev->of_node, 0, -1);
650 	if (!lt->host_node) {
651 		dev_err(lt->dev, "%s: Failed to get remote port\n", __func__);
652 		return -ENODEV;
653 	}
654 
655 	port_node = of_graph_get_remote_node(dev->of_node, 1, -1);
656 	if (!port_node) {
657 		dev_err(lt->dev, "%s: Failed to get connector port\n", __func__);
658 		ret = -ENODEV;
659 		goto err_free_host_node;
660 	}
661 
662 	lt->hdmi_port = of_drm_find_bridge(port_node);
663 	if (!lt->hdmi_port) {
664 		dev_err(lt->dev, "%s: Failed to get hdmi port\n", __func__);
665 		ret = -ENODEV;
666 		goto err_free_host_node;
667 	}
668 
669 	if (!of_device_is_compatible(port_node, "hdmi-connector")) {
670 		dev_err(lt->dev, "%s: Failed to get hdmi port\n", __func__);
671 		ret = -EINVAL;
672 		goto err_free_host_node;
673 	}
674 
675 	of_node_put(port_node);
676 	return 0;
677 
678 err_free_host_node:
679 	of_node_put(port_node);
680 	of_node_put(lt->host_node);
681 	return ret;
682 }
683 
684 static int lt8912_put_dt(struct lt8912 *lt)
685 {
686 	of_node_put(lt->host_node);
687 	return 0;
688 }
689 
690 static int lt8912_probe(struct i2c_client *client,
691 			const struct i2c_device_id *id)
692 {
693 	static struct lt8912 *lt;
694 	int ret = 0;
695 	struct device *dev = &client->dev;
696 
697 	lt = devm_kzalloc(dev, sizeof(struct lt8912), GFP_KERNEL);
698 	if (!lt)
699 		return -ENOMEM;
700 
701 	lt->dev = dev;
702 	lt->i2c_client[0] = client;
703 
704 	ret = lt8912_parse_dt(lt);
705 	if (ret)
706 		goto err_dt_parse;
707 
708 	ret = lt8912_init_i2c(lt, client);
709 	if (ret)
710 		goto err_i2c;
711 
712 	i2c_set_clientdata(client, lt);
713 
714 	lt->bridge.funcs = &lt8912_bridge_funcs;
715 	lt->bridge.of_node = dev->of_node;
716 	lt->bridge.ops = (DRM_BRIDGE_OP_EDID |
717 			  DRM_BRIDGE_OP_DETECT);
718 
719 	drm_bridge_add(&lt->bridge);
720 
721 	return 0;
722 
723 err_i2c:
724 	lt8912_put_dt(lt);
725 err_dt_parse:
726 	return ret;
727 }
728 
729 static int lt8912_remove(struct i2c_client *client)
730 {
731 	struct lt8912 *lt = i2c_get_clientdata(client);
732 
733 	lt8912_bridge_detach(&lt->bridge);
734 	drm_bridge_remove(&lt->bridge);
735 	lt8912_free_i2c(lt);
736 	lt8912_put_dt(lt);
737 	return 0;
738 }
739 
740 static const struct of_device_id lt8912_dt_match[] = {
741 	{.compatible = "lontium,lt8912b"},
742 	{}
743 };
744 MODULE_DEVICE_TABLE(of, lt8912_dt_match);
745 
746 static const struct i2c_device_id lt8912_id[] = {
747 	{"lt8912", 0},
748 	{},
749 };
750 MODULE_DEVICE_TABLE(i2c, lt8912_id);
751 
752 static struct i2c_driver lt8912_i2c_driver = {
753 	.driver = {
754 		.name = "lt8912",
755 		.of_match_table = lt8912_dt_match,
756 	},
757 	.probe = lt8912_probe,
758 	.remove = lt8912_remove,
759 	.id_table = lt8912_id,
760 };
761 module_i2c_driver(lt8912_i2c_driver);
762 
763 MODULE_AUTHOR("Adrien Grassein <adrien.grassein@gmail.com>");
764 MODULE_DESCRIPTION("lt8912 drm driver");
765 MODULE_LICENSE("GPL v2");
766