xref: /openbmc/linux/drivers/media/i2c/max9286.c (revision c4f7ac64)
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 /* Register 0x3f */
117 #define MAX9286_EN_REV_CFG		BIT(6)
118 #define MAX9286_REV_FLEN(n)		((n) - 20)
119 /* Register 0x49 */
120 #define MAX9286_VIDEO_DETECT_MASK	0x0f
121 /* Register 0x69 */
122 #define MAX9286_LFLTBMONMASKED		BIT(7)
123 #define MAX9286_LOCKMONMASKED		BIT(6)
124 #define MAX9286_AUTOCOMBACKEN		BIT(5)
125 #define MAX9286_AUTOMASKEN		BIT(4)
126 #define MAX9286_MASKLINK(n)		((n) << 0)
127 
128 /*
129  * The sink and source pads are created to match the OF graph port numbers so
130  * that their indexes can be used interchangeably.
131  */
132 #define MAX9286_NUM_GMSL		4
133 #define MAX9286_N_SINKS			4
134 #define MAX9286_N_PADS			5
135 #define MAX9286_SRC_PAD			4
136 
137 struct max9286_source {
138 	struct v4l2_subdev *sd;
139 	struct fwnode_handle *fwnode;
140 };
141 
142 struct max9286_asd {
143 	struct v4l2_async_subdev base;
144 	struct max9286_source *source;
145 };
146 
147 static inline struct max9286_asd *to_max9286_asd(struct v4l2_async_subdev *asd)
148 {
149 	return container_of(asd, struct max9286_asd, base);
150 }
151 
152 struct max9286_priv {
153 	struct i2c_client *client;
154 	struct gpio_desc *gpiod_pwdn;
155 	struct v4l2_subdev sd;
156 	struct media_pad pads[MAX9286_N_PADS];
157 	struct regulator *regulator;
158 
159 	struct gpio_chip gpio;
160 	u8 gpio_state;
161 
162 	struct i2c_mux_core *mux;
163 	unsigned int mux_channel;
164 	bool mux_open;
165 
166 	u32 reverse_channel_mv;
167 
168 	struct v4l2_ctrl_handler ctrls;
169 	struct v4l2_ctrl *pixelrate;
170 
171 	struct v4l2_mbus_framefmt fmt[MAX9286_N_SINKS];
172 
173 	/* Protects controls and fmt structures */
174 	struct mutex mutex;
175 
176 	unsigned int nsources;
177 	unsigned int source_mask;
178 	unsigned int route_mask;
179 	unsigned int bound_sources;
180 	unsigned int csi2_data_lanes;
181 	struct max9286_source sources[MAX9286_NUM_GMSL];
182 	struct v4l2_async_notifier notifier;
183 };
184 
185 static struct max9286_source *next_source(struct max9286_priv *priv,
186 					  struct max9286_source *source)
187 {
188 	if (!source)
189 		source = &priv->sources[0];
190 	else
191 		source++;
192 
193 	for (; source < &priv->sources[MAX9286_NUM_GMSL]; source++) {
194 		if (source->fwnode)
195 			return source;
196 	}
197 
198 	return NULL;
199 }
200 
201 #define for_each_source(priv, source) \
202 	for ((source) = NULL; ((source) = next_source((priv), (source))); )
203 
204 #define to_index(priv, source) ((source) - &(priv)->sources[0])
205 
206 static inline struct max9286_priv *sd_to_max9286(struct v4l2_subdev *sd)
207 {
208 	return container_of(sd, struct max9286_priv, sd);
209 }
210 
211 /* -----------------------------------------------------------------------------
212  * I2C IO
213  */
214 
215 static int max9286_read(struct max9286_priv *priv, u8 reg)
216 {
217 	int ret;
218 
219 	ret = i2c_smbus_read_byte_data(priv->client, reg);
220 	if (ret < 0)
221 		dev_err(&priv->client->dev,
222 			"%s: register 0x%02x read failed (%d)\n",
223 			__func__, reg, ret);
224 
225 	return ret;
226 }
227 
228 static int max9286_write(struct max9286_priv *priv, u8 reg, u8 val)
229 {
230 	int ret;
231 
232 	ret = i2c_smbus_write_byte_data(priv->client, reg, val);
233 	if (ret < 0)
234 		dev_err(&priv->client->dev,
235 			"%s: register 0x%02x write failed (%d)\n",
236 			__func__, reg, ret);
237 
238 	return ret;
239 }
240 
241 /* -----------------------------------------------------------------------------
242  * I2C Multiplexer
243  */
244 
245 static void max9286_i2c_mux_configure(struct max9286_priv *priv, u8 conf)
246 {
247 	max9286_write(priv, 0x0a, conf);
248 
249 	/*
250 	 * We must sleep after any change to the forward or reverse channel
251 	 * configuration.
252 	 */
253 	usleep_range(3000, 5000);
254 }
255 
256 static void max9286_i2c_mux_open(struct max9286_priv *priv)
257 {
258 	/* Open all channels on the MAX9286 */
259 	max9286_i2c_mux_configure(priv, 0xff);
260 
261 	priv->mux_open = true;
262 }
263 
264 static void max9286_i2c_mux_close(struct max9286_priv *priv)
265 {
266 	/*
267 	 * Ensure that both the forward and reverse channel are disabled on the
268 	 * mux, and that the channel ID is invalidated to ensure we reconfigure
269 	 * on the next max9286_i2c_mux_select() call.
270 	 */
271 	max9286_i2c_mux_configure(priv, 0x00);
272 
273 	priv->mux_open = false;
274 	priv->mux_channel = -1;
275 }
276 
277 static int max9286_i2c_mux_select(struct i2c_mux_core *muxc, u32 chan)
278 {
279 	struct max9286_priv *priv = i2c_mux_priv(muxc);
280 
281 	/* Channel select is disabled when configured in the opened state. */
282 	if (priv->mux_open)
283 		return 0;
284 
285 	if (priv->mux_channel == chan)
286 		return 0;
287 
288 	priv->mux_channel = chan;
289 
290 	max9286_i2c_mux_configure(priv,
291 				  MAX9286_FWDCCEN(chan) |
292 				  MAX9286_REVCCEN(chan));
293 
294 	return 0;
295 }
296 
297 static int max9286_i2c_mux_init(struct max9286_priv *priv)
298 {
299 	struct max9286_source *source;
300 	int ret;
301 
302 	if (!i2c_check_functionality(priv->client->adapter,
303 				     I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
304 		return -ENODEV;
305 
306 	priv->mux = i2c_mux_alloc(priv->client->adapter, &priv->client->dev,
307 				  priv->nsources, 0, I2C_MUX_LOCKED,
308 				  max9286_i2c_mux_select, NULL);
309 	if (!priv->mux)
310 		return -ENOMEM;
311 
312 	priv->mux->priv = priv;
313 
314 	for_each_source(priv, source) {
315 		unsigned int index = to_index(priv, source);
316 
317 		ret = i2c_mux_add_adapter(priv->mux, 0, index, 0);
318 		if (ret < 0)
319 			goto error;
320 	}
321 
322 	return 0;
323 
324 error:
325 	i2c_mux_del_adapters(priv->mux);
326 	return ret;
327 }
328 
329 static void max9286_configure_i2c(struct max9286_priv *priv, bool localack)
330 {
331 	u8 config = MAX9286_I2CSLVSH_469NS_234NS | MAX9286_I2CSLVTO_1024US |
332 		    MAX9286_I2CMSTBT_105KBPS;
333 
334 	if (localack)
335 		config |= MAX9286_I2CLOCACK;
336 
337 	max9286_write(priv, 0x34, config);
338 	usleep_range(3000, 5000);
339 }
340 
341 static void max9286_reverse_channel_setup(struct max9286_priv *priv,
342 					  unsigned int chan_amplitude)
343 {
344 	/* Reverse channel transmission time: default to 1. */
345 	u8 chan_config = MAX9286_REV_TRF(1);
346 
347 	/*
348 	 * Reverse channel setup.
349 	 *
350 	 * - Enable custom reverse channel configuration (through register 0x3f)
351 	 *   and set the first pulse length to 35 clock cycles.
352 	 * - Adjust reverse channel amplitude: values > 130 are programmed
353 	 *   using the additional +100mV REV_AMP_X boost flag
354 	 */
355 	max9286_write(priv, 0x3f, MAX9286_EN_REV_CFG | MAX9286_REV_FLEN(35));
356 
357 	if (chan_amplitude > 100) {
358 		/* It is not possible to express values (100 < x < 130) */
359 		chan_amplitude = max(30U, chan_amplitude - 100);
360 		chan_config |= MAX9286_REV_AMP_X;
361 	}
362 	max9286_write(priv, 0x3b, chan_config | MAX9286_REV_AMP(chan_amplitude));
363 	usleep_range(2000, 2500);
364 }
365 
366 /*
367  * max9286_check_video_links() - Make sure video links are detected and locked
368  *
369  * Performs safety checks on video link status. Make sure they are detected
370  * and all enabled links are locked.
371  *
372  * Returns 0 for success, -EIO for errors.
373  */
374 static int max9286_check_video_links(struct max9286_priv *priv)
375 {
376 	unsigned int i;
377 	int ret;
378 
379 	/*
380 	 * Make sure valid video links are detected.
381 	 * The delay is not characterized in de-serializer manual, wait up
382 	 * to 5 ms.
383 	 */
384 	for (i = 0; i < 10; i++) {
385 		ret = max9286_read(priv, 0x49);
386 		if (ret < 0)
387 			return -EIO;
388 
389 		if ((ret & MAX9286_VIDEO_DETECT_MASK) == priv->source_mask)
390 			break;
391 
392 		usleep_range(350, 500);
393 	}
394 
395 	if (i == 10) {
396 		dev_err(&priv->client->dev,
397 			"Unable to detect video links: 0x%02x\n", ret);
398 		return -EIO;
399 	}
400 
401 	/* Make sure all enabled links are locked (4ms max). */
402 	for (i = 0; i < 10; i++) {
403 		ret = max9286_read(priv, 0x27);
404 		if (ret < 0)
405 			return -EIO;
406 
407 		if (ret & MAX9286_LOCKED)
408 			break;
409 
410 		usleep_range(350, 450);
411 	}
412 
413 	if (i == 10) {
414 		dev_err(&priv->client->dev, "Not all enabled links locked\n");
415 		return -EIO;
416 	}
417 
418 	return 0;
419 }
420 
421 /*
422  * max9286_check_config_link() - Detect and wait for configuration links
423  *
424  * Determine if the configuration channel is up and settled for a link.
425  *
426  * Returns 0 for success, -EIO for errors.
427  */
428 static int max9286_check_config_link(struct max9286_priv *priv,
429 				     unsigned int source_mask)
430 {
431 	unsigned int conflink_mask = (source_mask & 0x0f) << 4;
432 	unsigned int i;
433 	int ret;
434 
435 	/*
436 	 * Make sure requested configuration links are detected.
437 	 * The delay is not characterized in the chip manual: wait up
438 	 * to 5 milliseconds.
439 	 */
440 	for (i = 0; i < 10; i++) {
441 		ret = max9286_read(priv, 0x49);
442 		if (ret < 0)
443 			return -EIO;
444 
445 		ret &= 0xf0;
446 		if (ret == conflink_mask)
447 			break;
448 
449 		usleep_range(350, 500);
450 	}
451 
452 	if (ret != conflink_mask) {
453 		dev_err(&priv->client->dev,
454 			"Unable to detect configuration links: 0x%02x expected 0x%02x\n",
455 			ret, conflink_mask);
456 		return -EIO;
457 	}
458 
459 	dev_info(&priv->client->dev,
460 		 "Successfully detected configuration links after %u loops: 0x%02x\n",
461 		 i, conflink_mask);
462 
463 	return 0;
464 }
465 
466 /* -----------------------------------------------------------------------------
467  * V4L2 Subdev
468  */
469 
470 static int max9286_set_pixelrate(struct max9286_priv *priv)
471 {
472 	struct max9286_source *source = NULL;
473 	u64 pixelrate = 0;
474 
475 	for_each_source(priv, source) {
476 		struct v4l2_ctrl *ctrl;
477 		u64 source_rate = 0;
478 
479 		/* Pixel rate is mandatory to be reported by sources. */
480 		ctrl = v4l2_ctrl_find(source->sd->ctrl_handler,
481 				      V4L2_CID_PIXEL_RATE);
482 		if (!ctrl) {
483 			pixelrate = 0;
484 			break;
485 		}
486 
487 		/* All source must report the same pixel rate. */
488 		source_rate = v4l2_ctrl_g_ctrl_int64(ctrl);
489 		if (!pixelrate) {
490 			pixelrate = source_rate;
491 		} else if (pixelrate != source_rate) {
492 			dev_err(&priv->client->dev,
493 				"Unable to calculate pixel rate\n");
494 			return -EINVAL;
495 		}
496 	}
497 
498 	if (!pixelrate) {
499 		dev_err(&priv->client->dev,
500 			"No pixel rate control available in sources\n");
501 		return -EINVAL;
502 	}
503 
504 	/*
505 	 * The CSI-2 transmitter pixel rate is the single source rate multiplied
506 	 * by the number of available sources.
507 	 */
508 	return v4l2_ctrl_s_ctrl_int64(priv->pixelrate,
509 				      pixelrate * priv->nsources);
510 }
511 
512 static int max9286_notify_bound(struct v4l2_async_notifier *notifier,
513 				struct v4l2_subdev *subdev,
514 				struct v4l2_async_subdev *asd)
515 {
516 	struct max9286_priv *priv = sd_to_max9286(notifier->sd);
517 	struct max9286_source *source = to_max9286_asd(asd)->source;
518 	unsigned int index = to_index(priv, source);
519 	unsigned int src_pad;
520 	int ret;
521 
522 	ret = media_entity_get_fwnode_pad(&subdev->entity,
523 					  source->fwnode,
524 					  MEDIA_PAD_FL_SOURCE);
525 	if (ret < 0) {
526 		dev_err(&priv->client->dev,
527 			"Failed to find pad for %s\n", subdev->name);
528 		return ret;
529 	}
530 
531 	priv->bound_sources |= BIT(index);
532 	source->sd = subdev;
533 	src_pad = ret;
534 
535 	ret = media_create_pad_link(&source->sd->entity, src_pad,
536 				    &priv->sd.entity, index,
537 				    MEDIA_LNK_FL_ENABLED |
538 				    MEDIA_LNK_FL_IMMUTABLE);
539 	if (ret) {
540 		dev_err(&priv->client->dev,
541 			"Unable to link %s:%u -> %s:%u\n",
542 			source->sd->name, src_pad, priv->sd.name, index);
543 		return ret;
544 	}
545 
546 	dev_dbg(&priv->client->dev, "Bound %s pad: %u on index %u\n",
547 		subdev->name, src_pad, index);
548 
549 	/*
550 	 * We can only register v4l2_async_notifiers, which do not provide a
551 	 * means to register a complete callback. bound_sources allows us to
552 	 * identify when all remote serializers have completed their probe.
553 	 */
554 	if (priv->bound_sources != priv->source_mask)
555 		return 0;
556 
557 	/*
558 	 * All enabled sources have probed and enabled their reverse control
559 	 * channels:
560 	 *
561 	 * - Increase the reverse channel amplitude to compensate for the
562 	 *   remote ends high threshold, if not done already
563 	 * - Verify all configuration links are properly detected
564 	 * - Disable auto-ack as communication on the control channel are now
565 	 *   stable.
566 	 */
567 	if (priv->reverse_channel_mv < 170)
568 		max9286_reverse_channel_setup(priv, 170);
569 	max9286_check_config_link(priv, priv->source_mask);
570 
571 	/*
572 	 * Re-configure I2C with local acknowledge disabled after cameras have
573 	 * probed.
574 	 */
575 	max9286_configure_i2c(priv, false);
576 
577 	return max9286_set_pixelrate(priv);
578 }
579 
580 static void max9286_notify_unbind(struct v4l2_async_notifier *notifier,
581 				  struct v4l2_subdev *subdev,
582 				  struct v4l2_async_subdev *asd)
583 {
584 	struct max9286_priv *priv = sd_to_max9286(notifier->sd);
585 	struct max9286_source *source = to_max9286_asd(asd)->source;
586 	unsigned int index = to_index(priv, source);
587 
588 	source->sd = NULL;
589 	priv->bound_sources &= ~BIT(index);
590 }
591 
592 static const struct v4l2_async_notifier_operations max9286_notify_ops = {
593 	.bound = max9286_notify_bound,
594 	.unbind = max9286_notify_unbind,
595 };
596 
597 static int max9286_v4l2_notifier_register(struct max9286_priv *priv)
598 {
599 	struct device *dev = &priv->client->dev;
600 	struct max9286_source *source = NULL;
601 	int ret;
602 
603 	if (!priv->nsources)
604 		return 0;
605 
606 	v4l2_async_notifier_init(&priv->notifier);
607 
608 	for_each_source(priv, source) {
609 		unsigned int i = to_index(priv, source);
610 		struct max9286_asd *mas;
611 
612 		mas = v4l2_async_notifier_add_fwnode_subdev(&priv->notifier,
613 							    source->fwnode,
614 							    struct max9286_asd);
615 		if (IS_ERR(mas)) {
616 			dev_err(dev, "Failed to add subdev for source %u: %ld",
617 				i, PTR_ERR(mas));
618 			v4l2_async_notifier_cleanup(&priv->notifier);
619 			return PTR_ERR(mas);
620 		}
621 
622 		mas->source = source;
623 	}
624 
625 	priv->notifier.ops = &max9286_notify_ops;
626 
627 	ret = v4l2_async_subdev_notifier_register(&priv->sd, &priv->notifier);
628 	if (ret) {
629 		dev_err(dev, "Failed to register subdev_notifier");
630 		v4l2_async_notifier_cleanup(&priv->notifier);
631 		return ret;
632 	}
633 
634 	return 0;
635 }
636 
637 static void max9286_v4l2_notifier_unregister(struct max9286_priv *priv)
638 {
639 	if (!priv->nsources)
640 		return;
641 
642 	v4l2_async_notifier_unregister(&priv->notifier);
643 	v4l2_async_notifier_cleanup(&priv->notifier);
644 }
645 
646 static int max9286_s_stream(struct v4l2_subdev *sd, int enable)
647 {
648 	struct max9286_priv *priv = sd_to_max9286(sd);
649 	struct max9286_source *source;
650 	unsigned int i;
651 	bool sync = false;
652 	int ret;
653 
654 	if (enable) {
655 		/*
656 		 * The frame sync between cameras is transmitted across the
657 		 * reverse channel as GPIO. We must open all channels while
658 		 * streaming to allow this synchronisation signal to be shared.
659 		 */
660 		max9286_i2c_mux_open(priv);
661 
662 		/* Start all cameras. */
663 		for_each_source(priv, source) {
664 			ret = v4l2_subdev_call(source->sd, video, s_stream, 1);
665 			if (ret)
666 				return ret;
667 		}
668 
669 		ret = max9286_check_video_links(priv);
670 		if (ret)
671 			return ret;
672 
673 		/*
674 		 * Wait until frame synchronization is locked.
675 		 *
676 		 * Manual says frame sync locking should take ~6 VTS.
677 		 * From practical experience at least 8 are required. Give
678 		 * 12 complete frames time (~400ms at 30 fps) to achieve frame
679 		 * locking before returning error.
680 		 */
681 		for (i = 0; i < 40; i++) {
682 			if (max9286_read(priv, 0x31) & MAX9286_FSYNC_LOCKED) {
683 				sync = true;
684 				break;
685 			}
686 			usleep_range(9000, 11000);
687 		}
688 
689 		if (!sync) {
690 			dev_err(&priv->client->dev,
691 				"Failed to get frame synchronization\n");
692 			return -EXDEV; /* Invalid cross-device link */
693 		}
694 
695 		/*
696 		 * Enable CSI output, VC set according to link number.
697 		 * Bit 7 must be set (chip manual says it's 0 and reserved).
698 		 */
699 		max9286_write(priv, 0x15, 0x80 | MAX9286_VCTYPE |
700 			      MAX9286_CSIOUTEN | MAX9286_0X15_RESV);
701 	} else {
702 		max9286_write(priv, 0x15, MAX9286_VCTYPE | MAX9286_0X15_RESV);
703 
704 		/* Stop all cameras. */
705 		for_each_source(priv, source)
706 			v4l2_subdev_call(source->sd, video, s_stream, 0);
707 
708 		max9286_i2c_mux_close(priv);
709 	}
710 
711 	return 0;
712 }
713 
714 static int max9286_enum_mbus_code(struct v4l2_subdev *sd,
715 				  struct v4l2_subdev_pad_config *cfg,
716 				  struct v4l2_subdev_mbus_code_enum *code)
717 {
718 	if (code->pad || code->index > 0)
719 		return -EINVAL;
720 
721 	code->code = MEDIA_BUS_FMT_UYVY8_1X16;
722 
723 	return 0;
724 }
725 
726 static struct v4l2_mbus_framefmt *
727 max9286_get_pad_format(struct max9286_priv *priv,
728 		       struct v4l2_subdev_pad_config *cfg,
729 		       unsigned int pad, u32 which)
730 {
731 	switch (which) {
732 	case V4L2_SUBDEV_FORMAT_TRY:
733 		return v4l2_subdev_get_try_format(&priv->sd, cfg, pad);
734 	case V4L2_SUBDEV_FORMAT_ACTIVE:
735 		return &priv->fmt[pad];
736 	default:
737 		return NULL;
738 	}
739 }
740 
741 static int max9286_set_fmt(struct v4l2_subdev *sd,
742 			   struct v4l2_subdev_pad_config *cfg,
743 			   struct v4l2_subdev_format *format)
744 {
745 	struct max9286_priv *priv = sd_to_max9286(sd);
746 	struct v4l2_mbus_framefmt *cfg_fmt;
747 
748 	if (format->pad == MAX9286_SRC_PAD)
749 		return -EINVAL;
750 
751 	/* Refuse non YUV422 formats as we hardcode DT to 8 bit YUV422 */
752 	switch (format->format.code) {
753 	case MEDIA_BUS_FMT_UYVY8_1X16:
754 	case MEDIA_BUS_FMT_VYUY8_1X16:
755 	case MEDIA_BUS_FMT_YUYV8_1X16:
756 	case MEDIA_BUS_FMT_YVYU8_1X16:
757 		break;
758 	default:
759 		format->format.code = MEDIA_BUS_FMT_UYVY8_1X16;
760 		break;
761 	}
762 
763 	cfg_fmt = max9286_get_pad_format(priv, cfg, format->pad, format->which);
764 	if (!cfg_fmt)
765 		return -EINVAL;
766 
767 	mutex_lock(&priv->mutex);
768 	*cfg_fmt = format->format;
769 	mutex_unlock(&priv->mutex);
770 
771 	return 0;
772 }
773 
774 static int max9286_get_fmt(struct v4l2_subdev *sd,
775 			   struct v4l2_subdev_pad_config *cfg,
776 			   struct v4l2_subdev_format *format)
777 {
778 	struct max9286_priv *priv = sd_to_max9286(sd);
779 	struct v4l2_mbus_framefmt *cfg_fmt;
780 	unsigned int pad = format->pad;
781 
782 	/*
783 	 * Multiplexed Stream Support: Support link validation by returning the
784 	 * format of the first bound link. All links must have the same format,
785 	 * as we do not support mixing and matching of cameras connected to the
786 	 * max9286.
787 	 */
788 	if (pad == MAX9286_SRC_PAD)
789 		pad = __ffs(priv->bound_sources);
790 
791 	cfg_fmt = max9286_get_pad_format(priv, cfg, pad, format->which);
792 	if (!cfg_fmt)
793 		return -EINVAL;
794 
795 	mutex_lock(&priv->mutex);
796 	format->format = *cfg_fmt;
797 	mutex_unlock(&priv->mutex);
798 
799 	return 0;
800 }
801 
802 static const struct v4l2_subdev_video_ops max9286_video_ops = {
803 	.s_stream	= max9286_s_stream,
804 };
805 
806 static const struct v4l2_subdev_pad_ops max9286_pad_ops = {
807 	.enum_mbus_code = max9286_enum_mbus_code,
808 	.get_fmt	= max9286_get_fmt,
809 	.set_fmt	= max9286_set_fmt,
810 };
811 
812 static const struct v4l2_subdev_ops max9286_subdev_ops = {
813 	.video		= &max9286_video_ops,
814 	.pad		= &max9286_pad_ops,
815 };
816 
817 static void max9286_init_format(struct v4l2_mbus_framefmt *fmt)
818 {
819 	fmt->width		= 1280;
820 	fmt->height		= 800;
821 	fmt->code		= MEDIA_BUS_FMT_UYVY8_1X16;
822 	fmt->colorspace		= V4L2_COLORSPACE_SRGB;
823 	fmt->field		= V4L2_FIELD_NONE;
824 	fmt->ycbcr_enc		= V4L2_YCBCR_ENC_DEFAULT;
825 	fmt->quantization	= V4L2_QUANTIZATION_DEFAULT;
826 	fmt->xfer_func		= V4L2_XFER_FUNC_DEFAULT;
827 }
828 
829 static int max9286_open(struct v4l2_subdev *subdev, struct v4l2_subdev_fh *fh)
830 {
831 	struct v4l2_mbus_framefmt *format;
832 	unsigned int i;
833 
834 	for (i = 0; i < MAX9286_N_SINKS; i++) {
835 		format = v4l2_subdev_get_try_format(subdev, fh->pad, i);
836 		max9286_init_format(format);
837 	}
838 
839 	return 0;
840 }
841 
842 static const struct v4l2_subdev_internal_ops max9286_subdev_internal_ops = {
843 	.open = max9286_open,
844 };
845 
846 static int max9286_s_ctrl(struct v4l2_ctrl *ctrl)
847 {
848 	switch (ctrl->id) {
849 	case V4L2_CID_PIXEL_RATE:
850 		return 0;
851 	default:
852 		return -EINVAL;
853 	}
854 }
855 
856 static const struct v4l2_ctrl_ops max9286_ctrl_ops = {
857 	.s_ctrl = max9286_s_ctrl,
858 };
859 
860 static int max9286_v4l2_register(struct max9286_priv *priv)
861 {
862 	struct device *dev = &priv->client->dev;
863 	struct fwnode_handle *ep;
864 	int ret;
865 	int i;
866 
867 	/* Register v4l2 async notifiers for connected Camera subdevices */
868 	ret = max9286_v4l2_notifier_register(priv);
869 	if (ret) {
870 		dev_err(dev, "Unable to register V4L2 async notifiers\n");
871 		return ret;
872 	}
873 
874 	/* Configure V4L2 for the MAX9286 itself */
875 
876 	for (i = 0; i < MAX9286_N_SINKS; i++)
877 		max9286_init_format(&priv->fmt[i]);
878 
879 	v4l2_i2c_subdev_init(&priv->sd, priv->client, &max9286_subdev_ops);
880 	priv->sd.internal_ops = &max9286_subdev_internal_ops;
881 	priv->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
882 
883 	v4l2_ctrl_handler_init(&priv->ctrls, 1);
884 	priv->pixelrate = v4l2_ctrl_new_std(&priv->ctrls,
885 					    &max9286_ctrl_ops,
886 					    V4L2_CID_PIXEL_RATE,
887 					    1, INT_MAX, 1, 50000000);
888 
889 	priv->sd.ctrl_handler = &priv->ctrls;
890 	ret = priv->ctrls.error;
891 	if (ret)
892 		goto err_async;
893 
894 	priv->sd.entity.function = MEDIA_ENT_F_VID_IF_BRIDGE;
895 
896 	priv->pads[MAX9286_SRC_PAD].flags = MEDIA_PAD_FL_SOURCE;
897 	for (i = 0; i < MAX9286_SRC_PAD; i++)
898 		priv->pads[i].flags = MEDIA_PAD_FL_SINK;
899 	ret = media_entity_pads_init(&priv->sd.entity, MAX9286_N_PADS,
900 				     priv->pads);
901 	if (ret)
902 		goto err_async;
903 
904 	ep = fwnode_graph_get_endpoint_by_id(dev_fwnode(dev), MAX9286_SRC_PAD,
905 					     0, 0);
906 	if (!ep) {
907 		dev_err(dev, "Unable to retrieve endpoint on \"port@4\"\n");
908 		ret = -ENOENT;
909 		goto err_async;
910 	}
911 	priv->sd.fwnode = ep;
912 
913 	ret = v4l2_async_register_subdev(&priv->sd);
914 	if (ret < 0) {
915 		dev_err(dev, "Unable to register subdevice\n");
916 		goto err_put_node;
917 	}
918 
919 	return 0;
920 
921 err_put_node:
922 	fwnode_handle_put(ep);
923 err_async:
924 	max9286_v4l2_notifier_unregister(priv);
925 
926 	return ret;
927 }
928 
929 static void max9286_v4l2_unregister(struct max9286_priv *priv)
930 {
931 	fwnode_handle_put(priv->sd.fwnode);
932 	v4l2_async_unregister_subdev(&priv->sd);
933 	max9286_v4l2_notifier_unregister(priv);
934 }
935 
936 /* -----------------------------------------------------------------------------
937  * Probe/Remove
938  */
939 
940 static int max9286_setup(struct max9286_priv *priv)
941 {
942 	/*
943 	 * Link ordering values for all enabled links combinations. Orders must
944 	 * be assigned sequentially from 0 to the number of enabled links
945 	 * without leaving any hole for disabled links. We thus assign orders to
946 	 * enabled links first, and use the remaining order values for disabled
947 	 * links are all links must have a different order value;
948 	 */
949 	static const u8 link_order[] = {
950 		(3 << 6) | (2 << 4) | (1 << 2) | (0 << 0), /* xxxx */
951 		(3 << 6) | (2 << 4) | (1 << 2) | (0 << 0), /* xxx0 */
952 		(3 << 6) | (2 << 4) | (0 << 2) | (1 << 0), /* xx0x */
953 		(3 << 6) | (2 << 4) | (1 << 2) | (0 << 0), /* xx10 */
954 		(3 << 6) | (0 << 4) | (2 << 2) | (1 << 0), /* x0xx */
955 		(3 << 6) | (1 << 4) | (2 << 2) | (0 << 0), /* x1x0 */
956 		(3 << 6) | (1 << 4) | (0 << 2) | (2 << 0), /* x10x */
957 		(3 << 6) | (1 << 4) | (1 << 2) | (0 << 0), /* x210 */
958 		(0 << 6) | (3 << 4) | (2 << 2) | (1 << 0), /* 0xxx */
959 		(1 << 6) | (3 << 4) | (2 << 2) | (0 << 0), /* 1xx0 */
960 		(1 << 6) | (3 << 4) | (0 << 2) | (2 << 0), /* 1x0x */
961 		(2 << 6) | (3 << 4) | (1 << 2) | (0 << 0), /* 2x10 */
962 		(1 << 6) | (0 << 4) | (3 << 2) | (2 << 0), /* 10xx */
963 		(2 << 6) | (1 << 4) | (3 << 2) | (0 << 0), /* 21x0 */
964 		(2 << 6) | (1 << 4) | (0 << 2) | (3 << 0), /* 210x */
965 		(3 << 6) | (2 << 4) | (1 << 2) | (0 << 0), /* 3210 */
966 	};
967 
968 	/*
969 	 * Set the I2C bus speed.
970 	 *
971 	 * Enable I2C Local Acknowledge during the probe sequences of the camera
972 	 * only. This should be disabled after the mux is initialised.
973 	 */
974 	max9286_configure_i2c(priv, true);
975 	max9286_reverse_channel_setup(priv, priv->reverse_channel_mv);
976 
977 	/*
978 	 * Enable GMSL links, mask unused ones and autodetect link
979 	 * used as CSI clock source.
980 	 */
981 	max9286_write(priv, 0x00, MAX9286_MSTLINKSEL_AUTO | priv->route_mask);
982 	max9286_write(priv, 0x0b, link_order[priv->route_mask]);
983 	max9286_write(priv, 0x69, (0xf & ~priv->route_mask));
984 
985 	/*
986 	 * Video format setup:
987 	 * Disable CSI output, VC is set according to Link number.
988 	 */
989 	max9286_write(priv, 0x15, MAX9286_VCTYPE | MAX9286_0X15_RESV);
990 
991 	/* Enable CSI-2 Lane D0-D3 only, DBL mode, YUV422 8-bit. */
992 	max9286_write(priv, 0x12, MAX9286_CSIDBL | MAX9286_DBL |
993 		      MAX9286_CSILANECNT(priv->csi2_data_lanes) |
994 		      MAX9286_DATATYPE_YUV422_8BIT);
995 
996 	/* Automatic: FRAMESYNC taken from the slowest Link. */
997 	max9286_write(priv, 0x01, MAX9286_FSYNCMODE_INT_HIZ |
998 		      MAX9286_FSYNCMETH_AUTO);
999 
1000 	/* Enable HS/VS encoding, use D14/15 for HS/VS, invert VS. */
1001 	max9286_write(priv, 0x0c, MAX9286_HVEN | MAX9286_INVVS |
1002 		      MAX9286_HVSRC_D14);
1003 
1004 	/*
1005 	 * The overlap window seems to provide additional validation by tracking
1006 	 * the delay between vsync and frame sync, generating an error if the
1007 	 * delay is bigger than the programmed window, though it's not yet clear
1008 	 * what value should be set.
1009 	 *
1010 	 * As it's an optional value and can be disabled, we do so by setting
1011 	 * a 0 overlap value.
1012 	 */
1013 	max9286_write(priv, 0x63, 0);
1014 	max9286_write(priv, 0x64, 0);
1015 
1016 	/*
1017 	 * Wait for 2ms to allow the link to resynchronize after the
1018 	 * configuration change.
1019 	 */
1020 	usleep_range(2000, 5000);
1021 
1022 	return 0;
1023 }
1024 
1025 static void max9286_gpio_set(struct gpio_chip *chip,
1026 			     unsigned int offset, int value)
1027 {
1028 	struct max9286_priv *priv = gpiochip_get_data(chip);
1029 
1030 	if (value)
1031 		priv->gpio_state |= BIT(offset);
1032 	else
1033 		priv->gpio_state &= ~BIT(offset);
1034 
1035 	max9286_write(priv, 0x0f, MAX9286_0X0F_RESERVED | priv->gpio_state);
1036 }
1037 
1038 static int max9286_gpio_get(struct gpio_chip *chip, unsigned int offset)
1039 {
1040 	struct max9286_priv *priv = gpiochip_get_data(chip);
1041 
1042 	return priv->gpio_state & BIT(offset);
1043 }
1044 
1045 static int max9286_register_gpio(struct max9286_priv *priv)
1046 {
1047 	struct device *dev = &priv->client->dev;
1048 	struct gpio_chip *gpio = &priv->gpio;
1049 	int ret;
1050 
1051 	/* Configure the GPIO */
1052 	gpio->label = dev_name(dev);
1053 	gpio->parent = dev;
1054 	gpio->owner = THIS_MODULE;
1055 	gpio->of_node = dev->of_node;
1056 	gpio->ngpio = 2;
1057 	gpio->base = -1;
1058 	gpio->set = max9286_gpio_set;
1059 	gpio->get = max9286_gpio_get;
1060 	gpio->can_sleep = true;
1061 
1062 	/* GPIO values default to high */
1063 	priv->gpio_state = BIT(0) | BIT(1);
1064 
1065 	ret = devm_gpiochip_add_data(dev, gpio, priv);
1066 	if (ret)
1067 		dev_err(dev, "Unable to create gpio_chip\n");
1068 
1069 	return ret;
1070 }
1071 
1072 static int max9286_init(struct device *dev)
1073 {
1074 	struct max9286_priv *priv;
1075 	struct i2c_client *client;
1076 	int ret;
1077 
1078 	client = to_i2c_client(dev);
1079 	priv = i2c_get_clientdata(client);
1080 
1081 	/* Enable the bus power. */
1082 	ret = regulator_enable(priv->regulator);
1083 	if (ret < 0) {
1084 		dev_err(&client->dev, "Unable to turn PoC on\n");
1085 		return ret;
1086 	}
1087 
1088 	ret = max9286_setup(priv);
1089 	if (ret) {
1090 		dev_err(dev, "Unable to setup max9286\n");
1091 		goto err_regulator;
1092 	}
1093 
1094 	/*
1095 	 * Register all V4L2 interactions for the MAX9286 and notifiers for
1096 	 * any subdevices connected.
1097 	 */
1098 	ret = max9286_v4l2_register(priv);
1099 	if (ret) {
1100 		dev_err(dev, "Failed to register with V4L2\n");
1101 		goto err_regulator;
1102 	}
1103 
1104 	ret = max9286_i2c_mux_init(priv);
1105 	if (ret) {
1106 		dev_err(dev, "Unable to initialize I2C multiplexer\n");
1107 		goto err_v4l2_register;
1108 	}
1109 
1110 	/* Leave the mux channels disabled until they are selected. */
1111 	max9286_i2c_mux_close(priv);
1112 
1113 	return 0;
1114 
1115 err_v4l2_register:
1116 	max9286_v4l2_unregister(priv);
1117 err_regulator:
1118 	regulator_disable(priv->regulator);
1119 
1120 	return ret;
1121 }
1122 
1123 static void max9286_cleanup_dt(struct max9286_priv *priv)
1124 {
1125 	struct max9286_source *source;
1126 
1127 	for_each_source(priv, source) {
1128 		fwnode_handle_put(source->fwnode);
1129 		source->fwnode = NULL;
1130 	}
1131 }
1132 
1133 static int max9286_parse_dt(struct max9286_priv *priv)
1134 {
1135 	struct device *dev = &priv->client->dev;
1136 	struct device_node *i2c_mux;
1137 	struct device_node *node = NULL;
1138 	unsigned int i2c_mux_mask = 0;
1139 	u32 reverse_channel_microvolt;
1140 
1141 	/* Balance the of_node_put() performed by of_find_node_by_name(). */
1142 	of_node_get(dev->of_node);
1143 	i2c_mux = of_find_node_by_name(dev->of_node, "i2c-mux");
1144 	if (!i2c_mux) {
1145 		dev_err(dev, "Failed to find i2c-mux node\n");
1146 		return -EINVAL;
1147 	}
1148 
1149 	/* Identify which i2c-mux channels are enabled */
1150 	for_each_child_of_node(i2c_mux, node) {
1151 		u32 id = 0;
1152 
1153 		of_property_read_u32(node, "reg", &id);
1154 		if (id >= MAX9286_NUM_GMSL)
1155 			continue;
1156 
1157 		if (!of_device_is_available(node)) {
1158 			dev_dbg(dev, "Skipping disabled I2C bus port %u\n", id);
1159 			continue;
1160 		}
1161 
1162 		i2c_mux_mask |= BIT(id);
1163 	}
1164 	of_node_put(node);
1165 	of_node_put(i2c_mux);
1166 
1167 	/* Parse the endpoints */
1168 	for_each_endpoint_of_node(dev->of_node, node) {
1169 		struct max9286_source *source;
1170 		struct of_endpoint ep;
1171 
1172 		of_graph_parse_endpoint(node, &ep);
1173 		dev_dbg(dev, "Endpoint %pOF on port %d",
1174 			ep.local_node, ep.port);
1175 
1176 		if (ep.port > MAX9286_NUM_GMSL) {
1177 			dev_err(dev, "Invalid endpoint %s on port %d",
1178 				of_node_full_name(ep.local_node), ep.port);
1179 			continue;
1180 		}
1181 
1182 		/* For the source endpoint just parse the bus configuration. */
1183 		if (ep.port == MAX9286_SRC_PAD) {
1184 			struct v4l2_fwnode_endpoint vep = {
1185 				.bus_type = V4L2_MBUS_CSI2_DPHY
1186 			};
1187 			int ret;
1188 
1189 			ret = v4l2_fwnode_endpoint_parse(
1190 					of_fwnode_handle(node), &vep);
1191 			if (ret) {
1192 				of_node_put(node);
1193 				return ret;
1194 			}
1195 
1196 			priv->csi2_data_lanes =
1197 				vep.bus.mipi_csi2.num_data_lanes;
1198 
1199 			continue;
1200 		}
1201 
1202 		/* Skip if the corresponding GMSL link is unavailable. */
1203 		if (!(i2c_mux_mask & BIT(ep.port)))
1204 			continue;
1205 
1206 		if (priv->sources[ep.port].fwnode) {
1207 			dev_err(dev,
1208 				"Multiple port endpoints are not supported: %d",
1209 				ep.port);
1210 
1211 			continue;
1212 		}
1213 
1214 		source = &priv->sources[ep.port];
1215 		source->fwnode = fwnode_graph_get_remote_endpoint(
1216 						of_fwnode_handle(node));
1217 		if (!source->fwnode) {
1218 			dev_err(dev,
1219 				"Endpoint %pOF has no remote endpoint connection\n",
1220 				ep.local_node);
1221 
1222 			continue;
1223 		}
1224 
1225 		priv->source_mask |= BIT(ep.port);
1226 		priv->nsources++;
1227 	}
1228 	of_node_put(node);
1229 
1230 	/*
1231 	 * Parse the initial value of the reverse channel amplitude from
1232 	 * the firmware interface and convert it to millivolts.
1233 	 *
1234 	 * Default it to 170mV for backward compatibility with DTBs that do not
1235 	 * provide the property.
1236 	 */
1237 	if (of_property_read_u32(dev->of_node,
1238 				 "maxim,reverse-channel-microvolt",
1239 				 &reverse_channel_microvolt))
1240 		priv->reverse_channel_mv = 170;
1241 	else
1242 		priv->reverse_channel_mv = reverse_channel_microvolt / 1000U;
1243 
1244 	priv->route_mask = priv->source_mask;
1245 
1246 	return 0;
1247 }
1248 
1249 static int max9286_probe(struct i2c_client *client)
1250 {
1251 	struct max9286_priv *priv;
1252 	int ret;
1253 
1254 	priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
1255 	if (!priv)
1256 		return -ENOMEM;
1257 
1258 	mutex_init(&priv->mutex);
1259 
1260 	priv->client = client;
1261 	i2c_set_clientdata(client, priv);
1262 
1263 	priv->gpiod_pwdn = devm_gpiod_get_optional(&client->dev, "enable",
1264 						   GPIOD_OUT_HIGH);
1265 	if (IS_ERR(priv->gpiod_pwdn))
1266 		return PTR_ERR(priv->gpiod_pwdn);
1267 
1268 	gpiod_set_consumer_name(priv->gpiod_pwdn, "max9286-pwdn");
1269 	gpiod_set_value_cansleep(priv->gpiod_pwdn, 1);
1270 
1271 	/* Wait at least 4ms before the I2C lines latch to the address */
1272 	if (priv->gpiod_pwdn)
1273 		usleep_range(4000, 5000);
1274 
1275 	/*
1276 	 * The MAX9286 starts by default with all ports enabled, we disable all
1277 	 * ports early to ensure that all channels are disabled if we error out
1278 	 * and keep the bus consistent.
1279 	 */
1280 	max9286_i2c_mux_close(priv);
1281 
1282 	/*
1283 	 * The MAX9286 initialises with auto-acknowledge enabled by default.
1284 	 * This can be invasive to other transactions on the same bus, so
1285 	 * disable it early. It will be enabled only as and when needed.
1286 	 */
1287 	max9286_configure_i2c(priv, false);
1288 
1289 	ret = max9286_register_gpio(priv);
1290 	if (ret)
1291 		goto err_powerdown;
1292 
1293 	priv->regulator = devm_regulator_get(&client->dev, "poc");
1294 	if (IS_ERR(priv->regulator)) {
1295 		if (PTR_ERR(priv->regulator) != -EPROBE_DEFER)
1296 			dev_err(&client->dev,
1297 				"Unable to get PoC regulator (%ld)\n",
1298 				PTR_ERR(priv->regulator));
1299 		ret = PTR_ERR(priv->regulator);
1300 		goto err_powerdown;
1301 	}
1302 
1303 	ret = max9286_parse_dt(priv);
1304 	if (ret)
1305 		goto err_powerdown;
1306 
1307 	ret = max9286_init(&client->dev);
1308 	if (ret < 0)
1309 		goto err_cleanup_dt;
1310 
1311 	return 0;
1312 
1313 err_cleanup_dt:
1314 	max9286_cleanup_dt(priv);
1315 err_powerdown:
1316 	gpiod_set_value_cansleep(priv->gpiod_pwdn, 0);
1317 
1318 	return ret;
1319 }
1320 
1321 static int max9286_remove(struct i2c_client *client)
1322 {
1323 	struct max9286_priv *priv = i2c_get_clientdata(client);
1324 
1325 	i2c_mux_del_adapters(priv->mux);
1326 
1327 	max9286_v4l2_unregister(priv);
1328 
1329 	regulator_disable(priv->regulator);
1330 
1331 	gpiod_set_value_cansleep(priv->gpiod_pwdn, 0);
1332 
1333 	max9286_cleanup_dt(priv);
1334 
1335 	return 0;
1336 }
1337 
1338 static const struct of_device_id max9286_dt_ids[] = {
1339 	{ .compatible = "maxim,max9286" },
1340 	{},
1341 };
1342 MODULE_DEVICE_TABLE(of, max9286_dt_ids);
1343 
1344 static struct i2c_driver max9286_i2c_driver = {
1345 	.driver	= {
1346 		.name		= "max9286",
1347 		.of_match_table	= of_match_ptr(max9286_dt_ids),
1348 	},
1349 	.probe_new	= max9286_probe,
1350 	.remove		= max9286_remove,
1351 };
1352 
1353 module_i2c_driver(max9286_i2c_driver);
1354 
1355 MODULE_DESCRIPTION("Maxim MAX9286 GMSL Deserializer Driver");
1356 MODULE_AUTHOR("Jacopo Mondi, Kieran Bingham, Laurent Pinchart, Niklas Söderlund, Vladimir Barinov");
1357 MODULE_LICENSE("GPL");
1358