xref: /openbmc/linux/drivers/media/i2c/max9286.c (revision 887069f4)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Maxim MAX9286 GMSL Deserializer Driver
4  *
5  * Copyright (C) 2017-2019 Jacopo Mondi
6  * Copyright (C) 2017-2019 Kieran Bingham
7  * Copyright (C) 2017-2019 Laurent Pinchart
8  * Copyright (C) 2017-2019 Niklas Söderlund
9  * Copyright (C) 2016 Renesas Electronics Corporation
10  * Copyright (C) 2015 Cogent Embedded, Inc.
11  */
12 
13 #include <linux/delay.h>
14 #include <linux/device.h>
15 #include <linux/fwnode.h>
16 #include <linux/gpio/consumer.h>
17 #include <linux/gpio/driver.h>
18 #include <linux/i2c.h>
19 #include <linux/i2c-mux.h>
20 #include <linux/module.h>
21 #include <linux/mutex.h>
22 #include <linux/of_graph.h>
23 #include <linux/regulator/consumer.h>
24 #include <linux/slab.h>
25 
26 #include <media/v4l2-async.h>
27 #include <media/v4l2-ctrls.h>
28 #include <media/v4l2-device.h>
29 #include <media/v4l2-fwnode.h>
30 #include <media/v4l2-subdev.h>
31 
32 /* Register 0x00 */
33 #define MAX9286_MSTLINKSEL_AUTO		(7 << 5)
34 #define MAX9286_MSTLINKSEL(n)		((n) << 5)
35 #define MAX9286_EN_VS_GEN		BIT(4)
36 #define MAX9286_LINKEN(n)		(1 << (n))
37 /* Register 0x01 */
38 #define MAX9286_FSYNCMODE_ECU		(3 << 6)
39 #define MAX9286_FSYNCMODE_EXT		(2 << 6)
40 #define MAX9286_FSYNCMODE_INT_OUT	(1 << 6)
41 #define MAX9286_FSYNCMODE_INT_HIZ	(0 << 6)
42 #define MAX9286_GPIEN			BIT(5)
43 #define MAX9286_ENLMO_RSTFSYNC		BIT(2)
44 #define MAX9286_FSYNCMETH_AUTO		(2 << 0)
45 #define MAX9286_FSYNCMETH_SEMI_AUTO	(1 << 0)
46 #define MAX9286_FSYNCMETH_MANUAL	(0 << 0)
47 #define MAX9286_REG_FSYNC_PERIOD_L	0x06
48 #define MAX9286_REG_FSYNC_PERIOD_M	0x07
49 #define MAX9286_REG_FSYNC_PERIOD_H	0x08
50 /* Register 0x0a */
51 #define MAX9286_FWDCCEN(n)		(1 << ((n) + 4))
52 #define MAX9286_REVCCEN(n)		(1 << (n))
53 /* Register 0x0c */
54 #define MAX9286_HVEN			BIT(7)
55 #define MAX9286_EDC_6BIT_HAMMING	(2 << 5)
56 #define MAX9286_EDC_6BIT_CRC		(1 << 5)
57 #define MAX9286_EDC_1BIT_PARITY		(0 << 5)
58 #define MAX9286_DESEL			BIT(4)
59 #define MAX9286_INVVS			BIT(3)
60 #define MAX9286_INVHS			BIT(2)
61 #define MAX9286_HVSRC_D0		(2 << 0)
62 #define MAX9286_HVSRC_D14		(1 << 0)
63 #define MAX9286_HVSRC_D18		(0 << 0)
64 /* Register 0x0f */
65 #define MAX9286_0X0F_RESERVED		BIT(3)
66 /* Register 0x12 */
67 #define MAX9286_CSILANECNT(n)		(((n) - 1) << 6)
68 #define MAX9286_CSIDBL			BIT(5)
69 #define MAX9286_DBL			BIT(4)
70 #define MAX9286_DATATYPE_USER_8BIT	(11 << 0)
71 #define MAX9286_DATATYPE_USER_YUV_12BIT	(10 << 0)
72 #define MAX9286_DATATYPE_USER_24BIT	(9 << 0)
73 #define MAX9286_DATATYPE_RAW14		(8 << 0)
74 #define MAX9286_DATATYPE_RAW11		(7 << 0)
75 #define MAX9286_DATATYPE_RAW10		(6 << 0)
76 #define MAX9286_DATATYPE_RAW8		(5 << 0)
77 #define MAX9286_DATATYPE_YUV422_10BIT	(4 << 0)
78 #define MAX9286_DATATYPE_YUV422_8BIT	(3 << 0)
79 #define MAX9286_DATATYPE_RGB555		(2 << 0)
80 #define MAX9286_DATATYPE_RGB565		(1 << 0)
81 #define MAX9286_DATATYPE_RGB888		(0 << 0)
82 /* Register 0x15 */
83 #define MAX9286_VC(n)			((n) << 5)
84 #define MAX9286_VCTYPE			BIT(4)
85 #define MAX9286_CSIOUTEN		BIT(3)
86 #define MAX9286_0X15_RESV		(3 << 0)
87 /* Register 0x1b */
88 #define MAX9286_SWITCHIN(n)		(1 << ((n) + 4))
89 #define MAX9286_ENEQ(n)			(1 << (n))
90 /* Register 0x27 */
91 #define MAX9286_LOCKED			BIT(7)
92 /* Register 0x31 */
93 #define MAX9286_FSYNC_LOCKED		BIT(6)
94 /* Register 0x34 */
95 #define MAX9286_I2CLOCACK		BIT(7)
96 #define MAX9286_I2CSLVSH_1046NS_469NS	(3 << 5)
97 #define MAX9286_I2CSLVSH_938NS_352NS	(2 << 5)
98 #define MAX9286_I2CSLVSH_469NS_234NS	(1 << 5)
99 #define MAX9286_I2CSLVSH_352NS_117NS	(0 << 5)
100 #define MAX9286_I2CMSTBT_837KBPS	(7 << 2)
101 #define MAX9286_I2CMSTBT_533KBPS	(6 << 2)
102 #define MAX9286_I2CMSTBT_339KBPS	(5 << 2)
103 #define MAX9286_I2CMSTBT_173KBPS	(4 << 2)
104 #define MAX9286_I2CMSTBT_105KBPS	(3 << 2)
105 #define MAX9286_I2CMSTBT_84KBPS		(2 << 2)
106 #define MAX9286_I2CMSTBT_28KBPS		(1 << 2)
107 #define MAX9286_I2CMSTBT_8KBPS		(0 << 2)
108 #define MAX9286_I2CSLVTO_NONE		(3 << 0)
109 #define MAX9286_I2CSLVTO_1024US		(2 << 0)
110 #define MAX9286_I2CSLVTO_256US		(1 << 0)
111 #define MAX9286_I2CSLVTO_64US		(0 << 0)
112 /* Register 0x3b */
113 #define MAX9286_REV_TRF(n)		((n) << 4)
114 #define MAX9286_REV_AMP(n)		((((n) - 30) / 10) << 1) /* in mV */
115 #define MAX9286_REV_AMP_X		BIT(0)
116 #define MAX9286_REV_AMP_HIGH		170
117 /* Register 0x3f */
118 #define MAX9286_EN_REV_CFG		BIT(6)
119 #define MAX9286_REV_FLEN(n)		((n) - 20)
120 /* Register 0x49 */
121 #define MAX9286_VIDEO_DETECT_MASK	0x0f
122 /* Register 0x69 */
123 #define MAX9286_LFLTBMONMASKED		BIT(7)
124 #define MAX9286_LOCKMONMASKED		BIT(6)
125 #define MAX9286_AUTOCOMBACKEN		BIT(5)
126 #define MAX9286_AUTOMASKEN		BIT(4)
127 #define MAX9286_MASKLINK(n)		((n) << 0)
128 
129 /*
130  * The sink and source pads are created to match the OF graph port numbers so
131  * that their indexes can be used interchangeably.
132  */
133 #define MAX9286_NUM_GMSL		4
134 #define MAX9286_N_SINKS			4
135 #define MAX9286_N_PADS			5
136 #define MAX9286_SRC_PAD			4
137 
138 struct max9286_source {
139 	struct v4l2_subdev *sd;
140 	struct fwnode_handle *fwnode;
141 };
142 
143 struct max9286_asd {
144 	struct v4l2_async_subdev base;
145 	struct max9286_source *source;
146 };
147 
148 static inline struct max9286_asd *to_max9286_asd(struct v4l2_async_subdev *asd)
149 {
150 	return container_of(asd, struct max9286_asd, base);
151 }
152 
153 struct max9286_priv {
154 	struct i2c_client *client;
155 	struct gpio_desc *gpiod_pwdn;
156 	struct v4l2_subdev sd;
157 	struct media_pad pads[MAX9286_N_PADS];
158 	struct regulator *regulator;
159 
160 	struct gpio_chip gpio;
161 	u8 gpio_state;
162 
163 	struct i2c_mux_core *mux;
164 	unsigned int mux_channel;
165 	bool mux_open;
166 
167 	/* The initial reverse control channel amplitude. */
168 	u32 init_rev_chan_mv;
169 	u32 rev_chan_mv;
170 
171 	struct v4l2_ctrl_handler ctrls;
172 	struct v4l2_ctrl *pixelrate;
173 
174 	struct v4l2_mbus_framefmt fmt[MAX9286_N_SINKS];
175 
176 	/* Protects controls and fmt structures */
177 	struct mutex mutex;
178 
179 	unsigned int nsources;
180 	unsigned int source_mask;
181 	unsigned int route_mask;
182 	unsigned int bound_sources;
183 	unsigned int csi2_data_lanes;
184 	struct max9286_source sources[MAX9286_NUM_GMSL];
185 	struct v4l2_async_notifier notifier;
186 };
187 
188 static struct max9286_source *next_source(struct max9286_priv *priv,
189 					  struct max9286_source *source)
190 {
191 	if (!source)
192 		source = &priv->sources[0];
193 	else
194 		source++;
195 
196 	for (; source < &priv->sources[MAX9286_NUM_GMSL]; source++) {
197 		if (source->fwnode)
198 			return source;
199 	}
200 
201 	return NULL;
202 }
203 
204 #define for_each_source(priv, source) \
205 	for ((source) = NULL; ((source) = next_source((priv), (source))); )
206 
207 #define to_index(priv, source) ((source) - &(priv)->sources[0])
208 
209 static inline struct max9286_priv *sd_to_max9286(struct v4l2_subdev *sd)
210 {
211 	return container_of(sd, struct max9286_priv, sd);
212 }
213 
214 /* -----------------------------------------------------------------------------
215  * I2C IO
216  */
217 
218 static int max9286_read(struct max9286_priv *priv, u8 reg)
219 {
220 	int ret;
221 
222 	ret = i2c_smbus_read_byte_data(priv->client, reg);
223 	if (ret < 0)
224 		dev_err(&priv->client->dev,
225 			"%s: register 0x%02x read failed (%d)\n",
226 			__func__, reg, ret);
227 
228 	return ret;
229 }
230 
231 static int max9286_write(struct max9286_priv *priv, u8 reg, u8 val)
232 {
233 	int ret;
234 
235 	ret = i2c_smbus_write_byte_data(priv->client, reg, val);
236 	if (ret < 0)
237 		dev_err(&priv->client->dev,
238 			"%s: register 0x%02x write failed (%d)\n",
239 			__func__, reg, ret);
240 
241 	return ret;
242 }
243 
244 /* -----------------------------------------------------------------------------
245  * I2C Multiplexer
246  */
247 
248 static void max9286_i2c_mux_configure(struct max9286_priv *priv, u8 conf)
249 {
250 	max9286_write(priv, 0x0a, conf);
251 
252 	/*
253 	 * We must sleep after any change to the forward or reverse channel
254 	 * configuration.
255 	 */
256 	usleep_range(3000, 5000);
257 }
258 
259 static void max9286_i2c_mux_open(struct max9286_priv *priv)
260 {
261 	/* Open all channels on the MAX9286 */
262 	max9286_i2c_mux_configure(priv, 0xff);
263 
264 	priv->mux_open = true;
265 }
266 
267 static void max9286_i2c_mux_close(struct max9286_priv *priv)
268 {
269 	/*
270 	 * Ensure that both the forward and reverse channel are disabled on the
271 	 * mux, and that the channel ID is invalidated to ensure we reconfigure
272 	 * on the next max9286_i2c_mux_select() call.
273 	 */
274 	max9286_i2c_mux_configure(priv, 0x00);
275 
276 	priv->mux_open = false;
277 	priv->mux_channel = -1;
278 }
279 
280 static int max9286_i2c_mux_select(struct i2c_mux_core *muxc, u32 chan)
281 {
282 	struct max9286_priv *priv = i2c_mux_priv(muxc);
283 
284 	/* Channel select is disabled when configured in the opened state. */
285 	if (priv->mux_open)
286 		return 0;
287 
288 	if (priv->mux_channel == chan)
289 		return 0;
290 
291 	priv->mux_channel = chan;
292 
293 	max9286_i2c_mux_configure(priv, MAX9286_FWDCCEN(chan) |
294 					MAX9286_REVCCEN(chan));
295 
296 	return 0;
297 }
298 
299 static int max9286_i2c_mux_init(struct max9286_priv *priv)
300 {
301 	struct max9286_source *source;
302 	int ret;
303 
304 	if (!i2c_check_functionality(priv->client->adapter,
305 				     I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
306 		return -ENODEV;
307 
308 	priv->mux = i2c_mux_alloc(priv->client->adapter, &priv->client->dev,
309 				  priv->nsources, 0, I2C_MUX_LOCKED,
310 				  max9286_i2c_mux_select, NULL);
311 	if (!priv->mux)
312 		return -ENOMEM;
313 
314 	priv->mux->priv = priv;
315 
316 	for_each_source(priv, source) {
317 		unsigned int index = to_index(priv, source);
318 
319 		ret = i2c_mux_add_adapter(priv->mux, 0, index, 0);
320 		if (ret < 0)
321 			goto error;
322 	}
323 
324 	return 0;
325 
326 error:
327 	i2c_mux_del_adapters(priv->mux);
328 	return ret;
329 }
330 
331 static void max9286_configure_i2c(struct max9286_priv *priv, bool localack)
332 {
333 	u8 config = MAX9286_I2CSLVSH_469NS_234NS | MAX9286_I2CSLVTO_1024US |
334 		    MAX9286_I2CMSTBT_105KBPS;
335 
336 	if (localack)
337 		config |= MAX9286_I2CLOCACK;
338 
339 	max9286_write(priv, 0x34, config);
340 	usleep_range(3000, 5000);
341 }
342 
343 static void max9286_reverse_channel_setup(struct max9286_priv *priv,
344 					  unsigned int chan_amplitude)
345 {
346 	u8 chan_config;
347 
348 	if (priv->rev_chan_mv == chan_amplitude)
349 		return;
350 
351 	priv->rev_chan_mv = chan_amplitude;
352 
353 	/* Reverse channel transmission time: default to 1. */
354 	chan_config = MAX9286_REV_TRF(1);
355 
356 	/*
357 	 * Reverse channel setup.
358 	 *
359 	 * - Enable custom reverse channel configuration (through register 0x3f)
360 	 *   and set the first pulse length to 35 clock cycles.
361 	 * - Adjust reverse channel amplitude: values > 130 are programmed
362 	 *   using the additional +100mV REV_AMP_X boost flag
363 	 */
364 	max9286_write(priv, 0x3f, MAX9286_EN_REV_CFG | MAX9286_REV_FLEN(35));
365 
366 	if (chan_amplitude > 100) {
367 		/* It is not possible to express values (100 < x < 130) */
368 		chan_amplitude = max(30U, chan_amplitude - 100);
369 		chan_config |= MAX9286_REV_AMP_X;
370 	}
371 	max9286_write(priv, 0x3b, chan_config | MAX9286_REV_AMP(chan_amplitude));
372 	usleep_range(2000, 2500);
373 }
374 
375 /*
376  * max9286_check_video_links() - Make sure video links are detected and locked
377  *
378  * Performs safety checks on video link status. Make sure they are detected
379  * and all enabled links are locked.
380  *
381  * Returns 0 for success, -EIO for errors.
382  */
383 static int max9286_check_video_links(struct max9286_priv *priv)
384 {
385 	unsigned int i;
386 	int ret;
387 
388 	/*
389 	 * Make sure valid video links are detected.
390 	 * The delay is not characterized in de-serializer manual, wait up
391 	 * to 5 ms.
392 	 */
393 	for (i = 0; i < 10; i++) {
394 		ret = max9286_read(priv, 0x49);
395 		if (ret < 0)
396 			return -EIO;
397 
398 		if ((ret & MAX9286_VIDEO_DETECT_MASK) == priv->source_mask)
399 			break;
400 
401 		usleep_range(350, 500);
402 	}
403 
404 	if (i == 10) {
405 		dev_err(&priv->client->dev,
406 			"Unable to detect video links: 0x%02x\n", ret);
407 		return -EIO;
408 	}
409 
410 	/* Make sure all enabled links are locked (4ms max). */
411 	for (i = 0; i < 10; i++) {
412 		ret = max9286_read(priv, 0x27);
413 		if (ret < 0)
414 			return -EIO;
415 
416 		if (ret & MAX9286_LOCKED)
417 			break;
418 
419 		usleep_range(350, 450);
420 	}
421 
422 	if (i == 10) {
423 		dev_err(&priv->client->dev, "Not all enabled links locked\n");
424 		return -EIO;
425 	}
426 
427 	return 0;
428 }
429 
430 /*
431  * max9286_check_config_link() - Detect and wait for configuration links
432  *
433  * Determine if the configuration channel is up and settled for a link.
434  *
435  * Returns 0 for success, -EIO for errors.
436  */
437 static int max9286_check_config_link(struct max9286_priv *priv,
438 				     unsigned int source_mask)
439 {
440 	unsigned int conflink_mask = (source_mask & 0x0f) << 4;
441 	unsigned int i;
442 	int ret;
443 
444 	/*
445 	 * Make sure requested configuration links are detected.
446 	 * The delay is not characterized in the chip manual: wait up
447 	 * to 5 milliseconds.
448 	 */
449 	for (i = 0; i < 10; i++) {
450 		ret = max9286_read(priv, 0x49);
451 		if (ret < 0)
452 			return -EIO;
453 
454 		ret &= 0xf0;
455 		if (ret == conflink_mask)
456 			break;
457 
458 		usleep_range(350, 500);
459 	}
460 
461 	if (ret != conflink_mask) {
462 		dev_err(&priv->client->dev,
463 			"Unable to detect configuration links: 0x%02x expected 0x%02x\n",
464 			ret, conflink_mask);
465 		return -EIO;
466 	}
467 
468 	dev_info(&priv->client->dev,
469 		 "Successfully detected configuration links after %u loops: 0x%02x\n",
470 		 i, conflink_mask);
471 
472 	return 0;
473 }
474 
475 /* -----------------------------------------------------------------------------
476  * V4L2 Subdev
477  */
478 
479 static int max9286_set_pixelrate(struct max9286_priv *priv)
480 {
481 	struct max9286_source *source = NULL;
482 	u64 pixelrate = 0;
483 
484 	for_each_source(priv, source) {
485 		struct v4l2_ctrl *ctrl;
486 		u64 source_rate = 0;
487 
488 		/* Pixel rate is mandatory to be reported by sources. */
489 		ctrl = v4l2_ctrl_find(source->sd->ctrl_handler,
490 				      V4L2_CID_PIXEL_RATE);
491 		if (!ctrl) {
492 			pixelrate = 0;
493 			break;
494 		}
495 
496 		/* All source must report the same pixel rate. */
497 		source_rate = v4l2_ctrl_g_ctrl_int64(ctrl);
498 		if (!pixelrate) {
499 			pixelrate = source_rate;
500 		} else if (pixelrate != source_rate) {
501 			dev_err(&priv->client->dev,
502 				"Unable to calculate pixel rate\n");
503 			return -EINVAL;
504 		}
505 	}
506 
507 	if (!pixelrate) {
508 		dev_err(&priv->client->dev,
509 			"No pixel rate control available in sources\n");
510 		return -EINVAL;
511 	}
512 
513 	/*
514 	 * The CSI-2 transmitter pixel rate is the single source rate multiplied
515 	 * by the number of available sources.
516 	 */
517 	return v4l2_ctrl_s_ctrl_int64(priv->pixelrate,
518 				      pixelrate * priv->nsources);
519 }
520 
521 static int max9286_notify_bound(struct v4l2_async_notifier *notifier,
522 				struct v4l2_subdev *subdev,
523 				struct v4l2_async_subdev *asd)
524 {
525 	struct max9286_priv *priv = sd_to_max9286(notifier->sd);
526 	struct max9286_source *source = to_max9286_asd(asd)->source;
527 	unsigned int index = to_index(priv, source);
528 	unsigned int src_pad;
529 	int ret;
530 
531 	ret = media_entity_get_fwnode_pad(&subdev->entity,
532 					  source->fwnode,
533 					  MEDIA_PAD_FL_SOURCE);
534 	if (ret < 0) {
535 		dev_err(&priv->client->dev,
536 			"Failed to find pad for %s\n", subdev->name);
537 		return ret;
538 	}
539 
540 	priv->bound_sources |= BIT(index);
541 	source->sd = subdev;
542 	src_pad = ret;
543 
544 	ret = media_create_pad_link(&source->sd->entity, src_pad,
545 				    &priv->sd.entity, index,
546 				    MEDIA_LNK_FL_ENABLED |
547 				    MEDIA_LNK_FL_IMMUTABLE);
548 	if (ret) {
549 		dev_err(&priv->client->dev,
550 			"Unable to link %s:%u -> %s:%u\n",
551 			source->sd->name, src_pad, priv->sd.name, index);
552 		return ret;
553 	}
554 
555 	dev_dbg(&priv->client->dev, "Bound %s pad: %u on index %u\n",
556 		subdev->name, src_pad, index);
557 
558 	/*
559 	 * As we register a subdev notifiers we won't get a .complete() callback
560 	 * here, so we have to use bound_sources to identify when all remote
561 	 * serializers have probed.
562 	 */
563 	if (priv->bound_sources != priv->source_mask)
564 		return 0;
565 
566 	/*
567 	 * All enabled sources have probed and enabled their reverse control
568 	 * channels:
569 	 *
570 	 * - Increase the reverse channel amplitude to compensate for the
571 	 *   remote ends high threshold
572 	 * - Verify all configuration links are properly detected
573 	 * - Disable auto-ack as communication on the control channel are now
574 	 *   stable.
575 	 */
576 	max9286_reverse_channel_setup(priv, MAX9286_REV_AMP_HIGH);
577 	max9286_check_config_link(priv, priv->source_mask);
578 	max9286_configure_i2c(priv, false);
579 
580 	return max9286_set_pixelrate(priv);
581 }
582 
583 static void max9286_notify_unbind(struct v4l2_async_notifier *notifier,
584 				  struct v4l2_subdev *subdev,
585 				  struct v4l2_async_subdev *asd)
586 {
587 	struct max9286_priv *priv = sd_to_max9286(notifier->sd);
588 	struct max9286_source *source = to_max9286_asd(asd)->source;
589 	unsigned int index = to_index(priv, source);
590 
591 	source->sd = NULL;
592 	priv->bound_sources &= ~BIT(index);
593 }
594 
595 static const struct v4l2_async_notifier_operations max9286_notify_ops = {
596 	.bound = max9286_notify_bound,
597 	.unbind = max9286_notify_unbind,
598 };
599 
600 static int max9286_v4l2_notifier_register(struct max9286_priv *priv)
601 {
602 	struct device *dev = &priv->client->dev;
603 	struct max9286_source *source = NULL;
604 	int ret;
605 
606 	if (!priv->nsources)
607 		return 0;
608 
609 	v4l2_async_nf_init(&priv->notifier);
610 
611 	for_each_source(priv, source) {
612 		unsigned int i = to_index(priv, source);
613 		struct max9286_asd *mas;
614 
615 		mas = v4l2_async_nf_add_fwnode(&priv->notifier, source->fwnode,
616 					       struct max9286_asd);
617 		if (IS_ERR(mas)) {
618 			dev_err(dev, "Failed to add subdev for source %u: %ld",
619 				i, PTR_ERR(mas));
620 			v4l2_async_nf_cleanup(&priv->notifier);
621 			return PTR_ERR(mas);
622 		}
623 
624 		mas->source = source;
625 	}
626 
627 	priv->notifier.ops = &max9286_notify_ops;
628 
629 	ret = v4l2_async_subdev_nf_register(&priv->sd, &priv->notifier);
630 	if (ret) {
631 		dev_err(dev, "Failed to register subdev_notifier");
632 		v4l2_async_nf_cleanup(&priv->notifier);
633 		return ret;
634 	}
635 
636 	return 0;
637 }
638 
639 static void max9286_v4l2_notifier_unregister(struct max9286_priv *priv)
640 {
641 	if (!priv->nsources)
642 		return;
643 
644 	v4l2_async_nf_unregister(&priv->notifier);
645 	v4l2_async_nf_cleanup(&priv->notifier);
646 }
647 
648 static int max9286_s_stream(struct v4l2_subdev *sd, int enable)
649 {
650 	struct max9286_priv *priv = sd_to_max9286(sd);
651 	struct max9286_source *source;
652 	unsigned int i;
653 	bool sync = false;
654 	int ret;
655 
656 	if (enable) {
657 		/*
658 		 * The frame sync between cameras is transmitted across the
659 		 * reverse channel as GPIO. We must open all channels while
660 		 * streaming to allow this synchronisation signal to be shared.
661 		 */
662 		max9286_i2c_mux_open(priv);
663 
664 		/* Start all cameras. */
665 		for_each_source(priv, source) {
666 			ret = v4l2_subdev_call(source->sd, video, s_stream, 1);
667 			if (ret)
668 				return ret;
669 		}
670 
671 		ret = max9286_check_video_links(priv);
672 		if (ret)
673 			return ret;
674 
675 		/*
676 		 * Wait until frame synchronization is locked.
677 		 *
678 		 * Manual says frame sync locking should take ~6 VTS.
679 		 * From practical experience at least 8 are required. Give
680 		 * 12 complete frames time (~400ms at 30 fps) to achieve frame
681 		 * locking before returning error.
682 		 */
683 		for (i = 0; i < 40; i++) {
684 			if (max9286_read(priv, 0x31) & MAX9286_FSYNC_LOCKED) {
685 				sync = true;
686 				break;
687 			}
688 			usleep_range(9000, 11000);
689 		}
690 
691 		if (!sync) {
692 			dev_err(&priv->client->dev,
693 				"Failed to get frame synchronization\n");
694 			return -EXDEV; /* Invalid cross-device link */
695 		}
696 
697 		/*
698 		 * Enable CSI output, VC set according to link number.
699 		 * Bit 7 must be set (chip manual says it's 0 and reserved).
700 		 */
701 		max9286_write(priv, 0x15, 0x80 | MAX9286_VCTYPE |
702 			      MAX9286_CSIOUTEN | MAX9286_0X15_RESV);
703 	} else {
704 		max9286_write(priv, 0x15, MAX9286_VCTYPE | MAX9286_0X15_RESV);
705 
706 		/* Stop all cameras. */
707 		for_each_source(priv, source)
708 			v4l2_subdev_call(source->sd, video, s_stream, 0);
709 
710 		max9286_i2c_mux_close(priv);
711 	}
712 
713 	return 0;
714 }
715 
716 static int max9286_enum_mbus_code(struct v4l2_subdev *sd,
717 				  struct v4l2_subdev_state *sd_state,
718 				  struct v4l2_subdev_mbus_code_enum *code)
719 {
720 	if (code->pad || code->index > 0)
721 		return -EINVAL;
722 
723 	code->code = MEDIA_BUS_FMT_UYVY8_1X16;
724 
725 	return 0;
726 }
727 
728 static struct v4l2_mbus_framefmt *
729 max9286_get_pad_format(struct max9286_priv *priv,
730 		       struct v4l2_subdev_state *sd_state,
731 		       unsigned int pad, u32 which)
732 {
733 	switch (which) {
734 	case V4L2_SUBDEV_FORMAT_TRY:
735 		return v4l2_subdev_get_try_format(&priv->sd, sd_state, pad);
736 	case V4L2_SUBDEV_FORMAT_ACTIVE:
737 		return &priv->fmt[pad];
738 	default:
739 		return NULL;
740 	}
741 }
742 
743 static int max9286_set_fmt(struct v4l2_subdev *sd,
744 			   struct v4l2_subdev_state *sd_state,
745 			   struct v4l2_subdev_format *format)
746 {
747 	struct max9286_priv *priv = sd_to_max9286(sd);
748 	struct v4l2_mbus_framefmt *cfg_fmt;
749 
750 	if (format->pad == MAX9286_SRC_PAD)
751 		return -EINVAL;
752 
753 	/* Refuse non YUV422 formats as we hardcode DT to 8 bit YUV422 */
754 	switch (format->format.code) {
755 	case MEDIA_BUS_FMT_UYVY8_1X16:
756 	case MEDIA_BUS_FMT_VYUY8_1X16:
757 	case MEDIA_BUS_FMT_YUYV8_1X16:
758 	case MEDIA_BUS_FMT_YVYU8_1X16:
759 		break;
760 	default:
761 		format->format.code = MEDIA_BUS_FMT_UYVY8_1X16;
762 		break;
763 	}
764 
765 	cfg_fmt = max9286_get_pad_format(priv, sd_state, format->pad,
766 					 format->which);
767 	if (!cfg_fmt)
768 		return -EINVAL;
769 
770 	mutex_lock(&priv->mutex);
771 	*cfg_fmt = format->format;
772 	mutex_unlock(&priv->mutex);
773 
774 	return 0;
775 }
776 
777 static int max9286_get_fmt(struct v4l2_subdev *sd,
778 			   struct v4l2_subdev_state *sd_state,
779 			   struct v4l2_subdev_format *format)
780 {
781 	struct max9286_priv *priv = sd_to_max9286(sd);
782 	struct v4l2_mbus_framefmt *cfg_fmt;
783 	unsigned int pad = format->pad;
784 
785 	/*
786 	 * Multiplexed Stream Support: Support link validation by returning the
787 	 * format of the first bound link. All links must have the same format,
788 	 * as we do not support mixing and matching of cameras connected to the
789 	 * max9286.
790 	 */
791 	if (pad == MAX9286_SRC_PAD)
792 		pad = __ffs(priv->bound_sources);
793 
794 	cfg_fmt = max9286_get_pad_format(priv, sd_state, pad, format->which);
795 	if (!cfg_fmt)
796 		return -EINVAL;
797 
798 	mutex_lock(&priv->mutex);
799 	format->format = *cfg_fmt;
800 	mutex_unlock(&priv->mutex);
801 
802 	return 0;
803 }
804 
805 static const struct v4l2_subdev_video_ops max9286_video_ops = {
806 	.s_stream	= max9286_s_stream,
807 };
808 
809 static const struct v4l2_subdev_pad_ops max9286_pad_ops = {
810 	.enum_mbus_code = max9286_enum_mbus_code,
811 	.get_fmt	= max9286_get_fmt,
812 	.set_fmt	= max9286_set_fmt,
813 };
814 
815 static const struct v4l2_subdev_ops max9286_subdev_ops = {
816 	.video		= &max9286_video_ops,
817 	.pad		= &max9286_pad_ops,
818 };
819 
820 static void max9286_init_format(struct v4l2_mbus_framefmt *fmt)
821 {
822 	fmt->width		= 1280;
823 	fmt->height		= 800;
824 	fmt->code		= MEDIA_BUS_FMT_UYVY8_1X16;
825 	fmt->colorspace		= V4L2_COLORSPACE_SRGB;
826 	fmt->field		= V4L2_FIELD_NONE;
827 	fmt->ycbcr_enc		= V4L2_YCBCR_ENC_DEFAULT;
828 	fmt->quantization	= V4L2_QUANTIZATION_DEFAULT;
829 	fmt->xfer_func		= V4L2_XFER_FUNC_DEFAULT;
830 }
831 
832 static int max9286_open(struct v4l2_subdev *subdev, struct v4l2_subdev_fh *fh)
833 {
834 	struct v4l2_mbus_framefmt *format;
835 	unsigned int i;
836 
837 	for (i = 0; i < MAX9286_N_SINKS; i++) {
838 		format = v4l2_subdev_get_try_format(subdev, fh->state, i);
839 		max9286_init_format(format);
840 	}
841 
842 	return 0;
843 }
844 
845 static const struct v4l2_subdev_internal_ops max9286_subdev_internal_ops = {
846 	.open = max9286_open,
847 };
848 
849 static int max9286_s_ctrl(struct v4l2_ctrl *ctrl)
850 {
851 	switch (ctrl->id) {
852 	case V4L2_CID_PIXEL_RATE:
853 		return 0;
854 	default:
855 		return -EINVAL;
856 	}
857 }
858 
859 static const struct v4l2_ctrl_ops max9286_ctrl_ops = {
860 	.s_ctrl = max9286_s_ctrl,
861 };
862 
863 static int max9286_v4l2_register(struct max9286_priv *priv)
864 {
865 	struct device *dev = &priv->client->dev;
866 	struct fwnode_handle *ep;
867 	int ret;
868 	int i;
869 
870 	/* Register v4l2 async notifiers for connected Camera subdevices */
871 	ret = max9286_v4l2_notifier_register(priv);
872 	if (ret) {
873 		dev_err(dev, "Unable to register V4L2 async notifiers\n");
874 		return ret;
875 	}
876 
877 	/* Configure V4L2 for the MAX9286 itself */
878 
879 	for (i = 0; i < MAX9286_N_SINKS; i++)
880 		max9286_init_format(&priv->fmt[i]);
881 
882 	v4l2_i2c_subdev_init(&priv->sd, priv->client, &max9286_subdev_ops);
883 	priv->sd.internal_ops = &max9286_subdev_internal_ops;
884 	priv->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
885 
886 	v4l2_ctrl_handler_init(&priv->ctrls, 1);
887 	priv->pixelrate = v4l2_ctrl_new_std(&priv->ctrls,
888 					    &max9286_ctrl_ops,
889 					    V4L2_CID_PIXEL_RATE,
890 					    1, INT_MAX, 1, 50000000);
891 
892 	priv->sd.ctrl_handler = &priv->ctrls;
893 	ret = priv->ctrls.error;
894 	if (ret)
895 		goto err_async;
896 
897 	priv->sd.entity.function = MEDIA_ENT_F_VID_IF_BRIDGE;
898 
899 	priv->pads[MAX9286_SRC_PAD].flags = MEDIA_PAD_FL_SOURCE;
900 	for (i = 0; i < MAX9286_SRC_PAD; i++)
901 		priv->pads[i].flags = MEDIA_PAD_FL_SINK;
902 	ret = media_entity_pads_init(&priv->sd.entity, MAX9286_N_PADS,
903 				     priv->pads);
904 	if (ret)
905 		goto err_async;
906 
907 	ep = fwnode_graph_get_endpoint_by_id(dev_fwnode(dev), MAX9286_SRC_PAD,
908 					     0, 0);
909 	if (!ep) {
910 		dev_err(dev, "Unable to retrieve endpoint on \"port@4\"\n");
911 		ret = -ENOENT;
912 		goto err_async;
913 	}
914 	priv->sd.fwnode = ep;
915 
916 	ret = v4l2_async_register_subdev(&priv->sd);
917 	if (ret < 0) {
918 		dev_err(dev, "Unable to register subdevice\n");
919 		goto err_put_node;
920 	}
921 
922 	return 0;
923 
924 err_put_node:
925 	fwnode_handle_put(ep);
926 err_async:
927 	max9286_v4l2_notifier_unregister(priv);
928 
929 	return ret;
930 }
931 
932 static void max9286_v4l2_unregister(struct max9286_priv *priv)
933 {
934 	fwnode_handle_put(priv->sd.fwnode);
935 	v4l2_async_unregister_subdev(&priv->sd);
936 	max9286_v4l2_notifier_unregister(priv);
937 }
938 
939 /* -----------------------------------------------------------------------------
940  * Probe/Remove
941  */
942 
943 static int max9286_setup(struct max9286_priv *priv)
944 {
945 	/*
946 	 * Link ordering values for all enabled links combinations. Orders must
947 	 * be assigned sequentially from 0 to the number of enabled links
948 	 * without leaving any hole for disabled links. We thus assign orders to
949 	 * enabled links first, and use the remaining order values for disabled
950 	 * links are all links must have a different order value;
951 	 */
952 	static const u8 link_order[] = {
953 		(3 << 6) | (2 << 4) | (1 << 2) | (0 << 0), /* xxxx */
954 		(3 << 6) | (2 << 4) | (1 << 2) | (0 << 0), /* xxx0 */
955 		(3 << 6) | (2 << 4) | (0 << 2) | (1 << 0), /* xx0x */
956 		(3 << 6) | (2 << 4) | (1 << 2) | (0 << 0), /* xx10 */
957 		(3 << 6) | (0 << 4) | (2 << 2) | (1 << 0), /* x0xx */
958 		(3 << 6) | (1 << 4) | (2 << 2) | (0 << 0), /* x1x0 */
959 		(3 << 6) | (1 << 4) | (0 << 2) | (2 << 0), /* x10x */
960 		(3 << 6) | (1 << 4) | (1 << 2) | (0 << 0), /* x210 */
961 		(0 << 6) | (3 << 4) | (2 << 2) | (1 << 0), /* 0xxx */
962 		(1 << 6) | (3 << 4) | (2 << 2) | (0 << 0), /* 1xx0 */
963 		(1 << 6) | (3 << 4) | (0 << 2) | (2 << 0), /* 1x0x */
964 		(2 << 6) | (3 << 4) | (1 << 2) | (0 << 0), /* 2x10 */
965 		(1 << 6) | (0 << 4) | (3 << 2) | (2 << 0), /* 10xx */
966 		(2 << 6) | (1 << 4) | (3 << 2) | (0 << 0), /* 21x0 */
967 		(2 << 6) | (1 << 4) | (0 << 2) | (3 << 0), /* 210x */
968 		(3 << 6) | (2 << 4) | (1 << 2) | (0 << 0), /* 3210 */
969 	};
970 
971 	/*
972 	 * Set the I2C bus speed.
973 	 *
974 	 * Enable I2C Local Acknowledge during the probe sequences of the camera
975 	 * only. This should be disabled after the mux is initialised.
976 	 */
977 	max9286_configure_i2c(priv, true);
978 	max9286_reverse_channel_setup(priv, priv->init_rev_chan_mv);
979 
980 	/*
981 	 * Enable GMSL links, mask unused ones and autodetect link
982 	 * used as CSI clock source.
983 	 */
984 	max9286_write(priv, 0x00, MAX9286_MSTLINKSEL_AUTO | priv->route_mask);
985 	max9286_write(priv, 0x0b, link_order[priv->route_mask]);
986 	max9286_write(priv, 0x69, (0xf & ~priv->route_mask));
987 
988 	/*
989 	 * Video format setup:
990 	 * Disable CSI output, VC is set according to Link number.
991 	 */
992 	max9286_write(priv, 0x15, MAX9286_VCTYPE | MAX9286_0X15_RESV);
993 
994 	/* Enable CSI-2 Lane D0-D3 only, DBL mode, YUV422 8-bit. */
995 	max9286_write(priv, 0x12, MAX9286_CSIDBL | MAX9286_DBL |
996 		      MAX9286_CSILANECNT(priv->csi2_data_lanes) |
997 		      MAX9286_DATATYPE_YUV422_8BIT);
998 
999 	/* Automatic: FRAMESYNC taken from the slowest Link. */
1000 	max9286_write(priv, 0x01, MAX9286_FSYNCMODE_INT_HIZ |
1001 		      MAX9286_FSYNCMETH_AUTO);
1002 
1003 	/* Enable HS/VS encoding, use D14/15 for HS/VS, invert VS. */
1004 	max9286_write(priv, 0x0c, MAX9286_HVEN | MAX9286_INVVS |
1005 		      MAX9286_HVSRC_D14);
1006 
1007 	/*
1008 	 * The overlap window seems to provide additional validation by tracking
1009 	 * the delay between vsync and frame sync, generating an error if the
1010 	 * delay is bigger than the programmed window, though it's not yet clear
1011 	 * what value should be set.
1012 	 *
1013 	 * As it's an optional value and can be disabled, we do so by setting
1014 	 * a 0 overlap value.
1015 	 */
1016 	max9286_write(priv, 0x63, 0);
1017 	max9286_write(priv, 0x64, 0);
1018 
1019 	/*
1020 	 * Wait for 2ms to allow the link to resynchronize after the
1021 	 * configuration change.
1022 	 */
1023 	usleep_range(2000, 5000);
1024 
1025 	return 0;
1026 }
1027 
1028 static void max9286_gpio_set(struct gpio_chip *chip,
1029 			     unsigned int offset, int value)
1030 {
1031 	struct max9286_priv *priv = gpiochip_get_data(chip);
1032 
1033 	if (value)
1034 		priv->gpio_state |= BIT(offset);
1035 	else
1036 		priv->gpio_state &= ~BIT(offset);
1037 
1038 	max9286_write(priv, 0x0f, MAX9286_0X0F_RESERVED | priv->gpio_state);
1039 }
1040 
1041 static int max9286_gpio_get(struct gpio_chip *chip, unsigned int offset)
1042 {
1043 	struct max9286_priv *priv = gpiochip_get_data(chip);
1044 
1045 	return priv->gpio_state & BIT(offset);
1046 }
1047 
1048 static int max9286_register_gpio(struct max9286_priv *priv)
1049 {
1050 	struct device *dev = &priv->client->dev;
1051 	struct gpio_chip *gpio = &priv->gpio;
1052 	int ret;
1053 
1054 	/* Configure the GPIO */
1055 	gpio->label = dev_name(dev);
1056 	gpio->parent = dev;
1057 	gpio->owner = THIS_MODULE;
1058 	gpio->of_node = dev->of_node;
1059 	gpio->ngpio = 2;
1060 	gpio->base = -1;
1061 	gpio->set = max9286_gpio_set;
1062 	gpio->get = max9286_gpio_get;
1063 	gpio->can_sleep = true;
1064 
1065 	/* GPIO values default to high */
1066 	priv->gpio_state = BIT(0) | BIT(1);
1067 
1068 	ret = devm_gpiochip_add_data(dev, gpio, priv);
1069 	if (ret)
1070 		dev_err(dev, "Unable to create gpio_chip\n");
1071 
1072 	return ret;
1073 }
1074 
1075 static int max9286_init(struct device *dev)
1076 {
1077 	struct max9286_priv *priv;
1078 	struct i2c_client *client;
1079 	int ret;
1080 
1081 	client = to_i2c_client(dev);
1082 	priv = i2c_get_clientdata(client);
1083 
1084 	/* Enable the bus power. */
1085 	ret = regulator_enable(priv->regulator);
1086 	if (ret < 0) {
1087 		dev_err(&client->dev, "Unable to turn PoC on\n");
1088 		return ret;
1089 	}
1090 
1091 	ret = max9286_setup(priv);
1092 	if (ret) {
1093 		dev_err(dev, "Unable to setup max9286\n");
1094 		goto err_regulator;
1095 	}
1096 
1097 	/*
1098 	 * Register all V4L2 interactions for the MAX9286 and notifiers for
1099 	 * any subdevices connected.
1100 	 */
1101 	ret = max9286_v4l2_register(priv);
1102 	if (ret) {
1103 		dev_err(dev, "Failed to register with V4L2\n");
1104 		goto err_regulator;
1105 	}
1106 
1107 	ret = max9286_i2c_mux_init(priv);
1108 	if (ret) {
1109 		dev_err(dev, "Unable to initialize I2C multiplexer\n");
1110 		goto err_v4l2_register;
1111 	}
1112 
1113 	/* Leave the mux channels disabled until they are selected. */
1114 	max9286_i2c_mux_close(priv);
1115 
1116 	return 0;
1117 
1118 err_v4l2_register:
1119 	max9286_v4l2_unregister(priv);
1120 err_regulator:
1121 	regulator_disable(priv->regulator);
1122 
1123 	return ret;
1124 }
1125 
1126 static void max9286_cleanup_dt(struct max9286_priv *priv)
1127 {
1128 	struct max9286_source *source;
1129 
1130 	for_each_source(priv, source) {
1131 		fwnode_handle_put(source->fwnode);
1132 		source->fwnode = NULL;
1133 	}
1134 }
1135 
1136 static int max9286_parse_dt(struct max9286_priv *priv)
1137 {
1138 	struct device *dev = &priv->client->dev;
1139 	struct device_node *i2c_mux;
1140 	struct device_node *node = NULL;
1141 	unsigned int i2c_mux_mask = 0;
1142 	u32 reverse_channel_microvolt;
1143 
1144 	/* Balance the of_node_put() performed by of_find_node_by_name(). */
1145 	of_node_get(dev->of_node);
1146 	i2c_mux = of_find_node_by_name(dev->of_node, "i2c-mux");
1147 	if (!i2c_mux) {
1148 		dev_err(dev, "Failed to find i2c-mux node\n");
1149 		return -EINVAL;
1150 	}
1151 
1152 	/* Identify which i2c-mux channels are enabled */
1153 	for_each_child_of_node(i2c_mux, node) {
1154 		u32 id = 0;
1155 
1156 		of_property_read_u32(node, "reg", &id);
1157 		if (id >= MAX9286_NUM_GMSL)
1158 			continue;
1159 
1160 		if (!of_device_is_available(node)) {
1161 			dev_dbg(dev, "Skipping disabled I2C bus port %u\n", id);
1162 			continue;
1163 		}
1164 
1165 		i2c_mux_mask |= BIT(id);
1166 	}
1167 	of_node_put(node);
1168 	of_node_put(i2c_mux);
1169 
1170 	/* Parse the endpoints */
1171 	for_each_endpoint_of_node(dev->of_node, node) {
1172 		struct max9286_source *source;
1173 		struct of_endpoint ep;
1174 
1175 		of_graph_parse_endpoint(node, &ep);
1176 		dev_dbg(dev, "Endpoint %pOF on port %d",
1177 			ep.local_node, ep.port);
1178 
1179 		if (ep.port > MAX9286_NUM_GMSL) {
1180 			dev_err(dev, "Invalid endpoint %s on port %d",
1181 				of_node_full_name(ep.local_node), ep.port);
1182 			continue;
1183 		}
1184 
1185 		/* For the source endpoint just parse the bus configuration. */
1186 		if (ep.port == MAX9286_SRC_PAD) {
1187 			struct v4l2_fwnode_endpoint vep = {
1188 				.bus_type = V4L2_MBUS_CSI2_DPHY
1189 			};
1190 			int ret;
1191 
1192 			ret = v4l2_fwnode_endpoint_parse(
1193 					of_fwnode_handle(node), &vep);
1194 			if (ret) {
1195 				of_node_put(node);
1196 				return ret;
1197 			}
1198 
1199 			priv->csi2_data_lanes =
1200 				vep.bus.mipi_csi2.num_data_lanes;
1201 
1202 			continue;
1203 		}
1204 
1205 		/* Skip if the corresponding GMSL link is unavailable. */
1206 		if (!(i2c_mux_mask & BIT(ep.port)))
1207 			continue;
1208 
1209 		if (priv->sources[ep.port].fwnode) {
1210 			dev_err(dev,
1211 				"Multiple port endpoints are not supported: %d",
1212 				ep.port);
1213 
1214 			continue;
1215 		}
1216 
1217 		source = &priv->sources[ep.port];
1218 		source->fwnode = fwnode_graph_get_remote_endpoint(
1219 						of_fwnode_handle(node));
1220 		if (!source->fwnode) {
1221 			dev_err(dev,
1222 				"Endpoint %pOF has no remote endpoint connection\n",
1223 				ep.local_node);
1224 
1225 			continue;
1226 		}
1227 
1228 		priv->source_mask |= BIT(ep.port);
1229 		priv->nsources++;
1230 	}
1231 	of_node_put(node);
1232 
1233 	/*
1234 	 * Parse the initial value of the reverse channel amplitude from
1235 	 * the firmware interface and convert it to millivolts.
1236 	 *
1237 	 * Default it to 170mV for backward compatibility with DTBs that do not
1238 	 * provide the property.
1239 	 */
1240 	if (of_property_read_u32(dev->of_node,
1241 				 "maxim,reverse-channel-microvolt",
1242 				 &reverse_channel_microvolt))
1243 		priv->init_rev_chan_mv = 170;
1244 	else
1245 		priv->init_rev_chan_mv = reverse_channel_microvolt / 1000U;
1246 
1247 	priv->route_mask = priv->source_mask;
1248 
1249 	return 0;
1250 }
1251 
1252 static int max9286_probe(struct i2c_client *client)
1253 {
1254 	struct max9286_priv *priv;
1255 	int ret;
1256 
1257 	priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
1258 	if (!priv)
1259 		return -ENOMEM;
1260 
1261 	mutex_init(&priv->mutex);
1262 
1263 	priv->client = client;
1264 	i2c_set_clientdata(client, priv);
1265 
1266 	priv->gpiod_pwdn = devm_gpiod_get_optional(&client->dev, "enable",
1267 						   GPIOD_OUT_HIGH);
1268 	if (IS_ERR(priv->gpiod_pwdn))
1269 		return PTR_ERR(priv->gpiod_pwdn);
1270 
1271 	gpiod_set_consumer_name(priv->gpiod_pwdn, "max9286-pwdn");
1272 	gpiod_set_value_cansleep(priv->gpiod_pwdn, 1);
1273 
1274 	/* Wait at least 4ms before the I2C lines latch to the address */
1275 	if (priv->gpiod_pwdn)
1276 		usleep_range(4000, 5000);
1277 
1278 	/*
1279 	 * The MAX9286 starts by default with all ports enabled, we disable all
1280 	 * ports early to ensure that all channels are disabled if we error out
1281 	 * and keep the bus consistent.
1282 	 */
1283 	max9286_i2c_mux_close(priv);
1284 
1285 	/*
1286 	 * The MAX9286 initialises with auto-acknowledge enabled by default.
1287 	 * This can be invasive to other transactions on the same bus, so
1288 	 * disable it early. It will be enabled only as and when needed.
1289 	 */
1290 	max9286_configure_i2c(priv, false);
1291 
1292 	ret = max9286_register_gpio(priv);
1293 	if (ret)
1294 		goto err_powerdown;
1295 
1296 	priv->regulator = devm_regulator_get(&client->dev, "poc");
1297 	if (IS_ERR(priv->regulator)) {
1298 		if (PTR_ERR(priv->regulator) != -EPROBE_DEFER)
1299 			dev_err(&client->dev,
1300 				"Unable to get PoC regulator (%ld)\n",
1301 				PTR_ERR(priv->regulator));
1302 		ret = PTR_ERR(priv->regulator);
1303 		goto err_powerdown;
1304 	}
1305 
1306 	ret = max9286_parse_dt(priv);
1307 	if (ret)
1308 		goto err_powerdown;
1309 
1310 	ret = max9286_init(&client->dev);
1311 	if (ret < 0)
1312 		goto err_cleanup_dt;
1313 
1314 	return 0;
1315 
1316 err_cleanup_dt:
1317 	max9286_cleanup_dt(priv);
1318 err_powerdown:
1319 	gpiod_set_value_cansleep(priv->gpiod_pwdn, 0);
1320 
1321 	return ret;
1322 }
1323 
1324 static int max9286_remove(struct i2c_client *client)
1325 {
1326 	struct max9286_priv *priv = i2c_get_clientdata(client);
1327 
1328 	i2c_mux_del_adapters(priv->mux);
1329 
1330 	max9286_v4l2_unregister(priv);
1331 
1332 	regulator_disable(priv->regulator);
1333 
1334 	gpiod_set_value_cansleep(priv->gpiod_pwdn, 0);
1335 
1336 	max9286_cleanup_dt(priv);
1337 
1338 	return 0;
1339 }
1340 
1341 static const struct of_device_id max9286_dt_ids[] = {
1342 	{ .compatible = "maxim,max9286" },
1343 	{},
1344 };
1345 MODULE_DEVICE_TABLE(of, max9286_dt_ids);
1346 
1347 static struct i2c_driver max9286_i2c_driver = {
1348 	.driver	= {
1349 		.name		= "max9286",
1350 		.of_match_table	= of_match_ptr(max9286_dt_ids),
1351 	},
1352 	.probe_new	= max9286_probe,
1353 	.remove		= max9286_remove,
1354 };
1355 
1356 module_i2c_driver(max9286_i2c_driver);
1357 
1358 MODULE_DESCRIPTION("Maxim MAX9286 GMSL Deserializer Driver");
1359 MODULE_AUTHOR("Jacopo Mondi, Kieran Bingham, Laurent Pinchart, Niklas Söderlund, Vladimir Barinov");
1360 MODULE_LICENSE("GPL");
1361