xref: /linux/drivers/media/i2c/max9286.c (revision d6a5c562214f26e442c8ec3ff1e28e16675d1bcf)
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/gpio/machine.h>
19 #include <linux/i2c.h>
20 #include <linux/i2c-mux.h>
21 #include <linux/module.h>
22 #include <linux/mutex.h>
23 #include <linux/of_graph.h>
24 #include <linux/regulator/consumer.h>
25 #include <linux/slab.h>
26 
27 #include <media/v4l2-async.h>
28 #include <media/v4l2-ctrls.h>
29 #include <media/v4l2-device.h>
30 #include <media/v4l2-fwnode.h>
31 #include <media/v4l2-subdev.h>
32 
33 /* Register 0x00 */
34 #define MAX9286_MSTLINKSEL_AUTO		(7 << 5)
35 #define MAX9286_MSTLINKSEL(n)		((n) << 5)
36 #define MAX9286_EN_VS_GEN		BIT(4)
37 #define MAX9286_LINKEN(n)		(1 << (n))
38 /* Register 0x01 */
39 #define MAX9286_FSYNCMODE_ECU		(3 << 6)
40 #define MAX9286_FSYNCMODE_EXT		(2 << 6)
41 #define MAX9286_FSYNCMODE_INT_OUT	(1 << 6)
42 #define MAX9286_FSYNCMODE_INT_HIZ	(0 << 6)
43 #define MAX9286_GPIEN			BIT(5)
44 #define MAX9286_ENLMO_RSTFSYNC		BIT(2)
45 #define MAX9286_FSYNCMETH_AUTO		(2 << 0)
46 #define MAX9286_FSYNCMETH_SEMI_AUTO	(1 << 0)
47 #define MAX9286_FSYNCMETH_MANUAL	(0 << 0)
48 #define MAX9286_REG_FSYNC_PERIOD_L	0x06
49 #define MAX9286_REG_FSYNC_PERIOD_M	0x07
50 #define MAX9286_REG_FSYNC_PERIOD_H	0x08
51 /* Register 0x0a */
52 #define MAX9286_FWDCCEN(n)		(1 << ((n) + 4))
53 #define MAX9286_REVCCEN(n)		(1 << (n))
54 /* Register 0x0c */
55 #define MAX9286_HVEN			BIT(7)
56 #define MAX9286_EDC_6BIT_HAMMING	(2 << 5)
57 #define MAX9286_EDC_6BIT_CRC		(1 << 5)
58 #define MAX9286_EDC_1BIT_PARITY		(0 << 5)
59 #define MAX9286_DESEL			BIT(4)
60 #define MAX9286_INVVS			BIT(3)
61 #define MAX9286_INVHS			BIT(2)
62 #define MAX9286_HVSRC_D0		(2 << 0)
63 #define MAX9286_HVSRC_D14		(1 << 0)
64 #define MAX9286_HVSRC_D18		(0 << 0)
65 /* Register 0x0f */
66 #define MAX9286_0X0F_RESERVED		BIT(3)
67 /* Register 0x12 */
68 #define MAX9286_CSILANECNT(n)		(((n) - 1) << 6)
69 #define MAX9286_CSIDBL			BIT(5)
70 #define MAX9286_DBL			BIT(4)
71 #define MAX9286_DATATYPE_USER_8BIT	(11 << 0)
72 #define MAX9286_DATATYPE_USER_YUV_12BIT	(10 << 0)
73 #define MAX9286_DATATYPE_USER_24BIT	(9 << 0)
74 #define MAX9286_DATATYPE_RAW14		(8 << 0)
75 #define MAX9286_DATATYPE_RAW11		(7 << 0)
76 #define MAX9286_DATATYPE_RAW10		(6 << 0)
77 #define MAX9286_DATATYPE_RAW8		(5 << 0)
78 #define MAX9286_DATATYPE_YUV422_10BIT	(4 << 0)
79 #define MAX9286_DATATYPE_YUV422_8BIT	(3 << 0)
80 #define MAX9286_DATATYPE_RGB555		(2 << 0)
81 #define MAX9286_DATATYPE_RGB565		(1 << 0)
82 #define MAX9286_DATATYPE_RGB888		(0 << 0)
83 /* Register 0x15 */
84 #define MAX9286_VC(n)			((n) << 5)
85 #define MAX9286_VCTYPE			BIT(4)
86 #define MAX9286_CSIOUTEN		BIT(3)
87 #define MAX9286_0X15_RESV		(3 << 0)
88 /* Register 0x1b */
89 #define MAX9286_SWITCHIN(n)		(1 << ((n) + 4))
90 #define MAX9286_ENEQ(n)			(1 << (n))
91 /* Register 0x27 */
92 #define MAX9286_LOCKED			BIT(7)
93 /* Register 0x31 */
94 #define MAX9286_FSYNC_LOCKED		BIT(6)
95 /* Register 0x34 */
96 #define MAX9286_I2CLOCACK		BIT(7)
97 #define MAX9286_I2CSLVSH_1046NS_469NS	(3 << 5)
98 #define MAX9286_I2CSLVSH_938NS_352NS	(2 << 5)
99 #define MAX9286_I2CSLVSH_469NS_234NS	(1 << 5)
100 #define MAX9286_I2CSLVSH_352NS_117NS	(0 << 5)
101 #define MAX9286_I2CMSTBT_837KBPS	(7 << 2)
102 #define MAX9286_I2CMSTBT_533KBPS	(6 << 2)
103 #define MAX9286_I2CMSTBT_339KBPS	(5 << 2)
104 #define MAX9286_I2CMSTBT_173KBPS	(4 << 2)
105 #define MAX9286_I2CMSTBT_105KBPS	(3 << 2)
106 #define MAX9286_I2CMSTBT_84KBPS		(2 << 2)
107 #define MAX9286_I2CMSTBT_28KBPS		(1 << 2)
108 #define MAX9286_I2CMSTBT_8KBPS		(0 << 2)
109 #define MAX9286_I2CSLVTO_NONE		(3 << 0)
110 #define MAX9286_I2CSLVTO_1024US		(2 << 0)
111 #define MAX9286_I2CSLVTO_256US		(1 << 0)
112 #define MAX9286_I2CSLVTO_64US		(0 << 0)
113 /* Register 0x3b */
114 #define MAX9286_REV_TRF(n)		((n) << 4)
115 #define MAX9286_REV_AMP(n)		((((n) - 30) / 10) << 1) /* in mV */
116 #define MAX9286_REV_AMP_X		BIT(0)
117 #define MAX9286_REV_AMP_HIGH		170
118 /* Register 0x3f */
119 #define MAX9286_EN_REV_CFG		BIT(6)
120 #define MAX9286_REV_FLEN(n)		((n) - 20)
121 /* Register 0x49 */
122 #define MAX9286_VIDEO_DETECT_MASK	0x0f
123 /* Register 0x69 */
124 #define MAX9286_LFLTBMONMASKED		BIT(7)
125 #define MAX9286_LOCKMONMASKED		BIT(6)
126 #define MAX9286_AUTOCOMBACKEN		BIT(5)
127 #define MAX9286_AUTOMASKEN		BIT(4)
128 #define MAX9286_MASKLINK(n)		((n) << 0)
129 
130 /*
131  * The sink and source pads are created to match the OF graph port numbers so
132  * that their indexes can be used interchangeably.
133  */
134 #define MAX9286_NUM_GMSL		4
135 #define MAX9286_N_SINKS			4
136 #define MAX9286_N_PADS			5
137 #define MAX9286_SRC_PAD			4
138 
139 struct max9286_source {
140 	struct v4l2_subdev *sd;
141 	struct fwnode_handle *fwnode;
142 };
143 
144 struct max9286_asd {
145 	struct v4l2_async_subdev base;
146 	struct max9286_source *source;
147 };
148 
149 static inline struct max9286_asd *to_max9286_asd(struct v4l2_async_subdev *asd)
150 {
151 	return container_of(asd, struct max9286_asd, base);
152 }
153 
154 struct max9286_priv {
155 	struct i2c_client *client;
156 	struct gpio_desc *gpiod_pwdn;
157 	struct v4l2_subdev sd;
158 	struct media_pad pads[MAX9286_N_PADS];
159 	struct regulator *regulator;
160 
161 	struct gpio_chip gpio;
162 	u8 gpio_state;
163 
164 	struct i2c_mux_core *mux;
165 	unsigned int mux_channel;
166 	bool mux_open;
167 
168 	/* The initial reverse control channel amplitude. */
169 	u32 init_rev_chan_mv;
170 	u32 rev_chan_mv;
171 
172 	u32 gpio_poc[2];
173 
174 	struct v4l2_ctrl_handler ctrls;
175 	struct v4l2_ctrl *pixelrate;
176 
177 	struct v4l2_mbus_framefmt fmt[MAX9286_N_SINKS];
178 
179 	/* Protects controls and fmt structures */
180 	struct mutex mutex;
181 
182 	unsigned int nsources;
183 	unsigned int source_mask;
184 	unsigned int route_mask;
185 	unsigned int bound_sources;
186 	unsigned int csi2_data_lanes;
187 	struct max9286_source sources[MAX9286_NUM_GMSL];
188 	struct v4l2_async_notifier notifier;
189 };
190 
191 static struct max9286_source *next_source(struct max9286_priv *priv,
192 					  struct max9286_source *source)
193 {
194 	if (!source)
195 		source = &priv->sources[0];
196 	else
197 		source++;
198 
199 	for (; source < &priv->sources[MAX9286_NUM_GMSL]; source++) {
200 		if (source->fwnode)
201 			return source;
202 	}
203 
204 	return NULL;
205 }
206 
207 #define for_each_source(priv, source) \
208 	for ((source) = NULL; ((source) = next_source((priv), (source))); )
209 
210 #define to_index(priv, source) ((source) - &(priv)->sources[0])
211 
212 static inline struct max9286_priv *sd_to_max9286(struct v4l2_subdev *sd)
213 {
214 	return container_of(sd, struct max9286_priv, sd);
215 }
216 
217 /* -----------------------------------------------------------------------------
218  * I2C IO
219  */
220 
221 static int max9286_read(struct max9286_priv *priv, u8 reg)
222 {
223 	int ret;
224 
225 	ret = i2c_smbus_read_byte_data(priv->client, reg);
226 	if (ret < 0)
227 		dev_err(&priv->client->dev,
228 			"%s: register 0x%02x read failed (%d)\n",
229 			__func__, reg, ret);
230 
231 	return ret;
232 }
233 
234 static int max9286_write(struct max9286_priv *priv, u8 reg, u8 val)
235 {
236 	int ret;
237 
238 	ret = i2c_smbus_write_byte_data(priv->client, reg, val);
239 	if (ret < 0)
240 		dev_err(&priv->client->dev,
241 			"%s: register 0x%02x write failed (%d)\n",
242 			__func__, reg, ret);
243 
244 	return ret;
245 }
246 
247 /* -----------------------------------------------------------------------------
248  * I2C Multiplexer
249  */
250 
251 static void max9286_i2c_mux_configure(struct max9286_priv *priv, u8 conf)
252 {
253 	max9286_write(priv, 0x0a, conf);
254 
255 	/*
256 	 * We must sleep after any change to the forward or reverse channel
257 	 * configuration.
258 	 */
259 	usleep_range(3000, 5000);
260 }
261 
262 static void max9286_i2c_mux_open(struct max9286_priv *priv)
263 {
264 	/* Open all channels on the MAX9286 */
265 	max9286_i2c_mux_configure(priv, 0xff);
266 
267 	priv->mux_open = true;
268 }
269 
270 static void max9286_i2c_mux_close(struct max9286_priv *priv)
271 {
272 	/*
273 	 * Ensure that both the forward and reverse channel are disabled on the
274 	 * mux, and that the channel ID is invalidated to ensure we reconfigure
275 	 * on the next max9286_i2c_mux_select() call.
276 	 */
277 	max9286_i2c_mux_configure(priv, 0x00);
278 
279 	priv->mux_open = false;
280 	priv->mux_channel = -1;
281 }
282 
283 static int max9286_i2c_mux_select(struct i2c_mux_core *muxc, u32 chan)
284 {
285 	struct max9286_priv *priv = i2c_mux_priv(muxc);
286 
287 	/* Channel select is disabled when configured in the opened state. */
288 	if (priv->mux_open)
289 		return 0;
290 
291 	if (priv->mux_channel == chan)
292 		return 0;
293 
294 	priv->mux_channel = chan;
295 
296 	max9286_i2c_mux_configure(priv, MAX9286_FWDCCEN(chan) |
297 					MAX9286_REVCCEN(chan));
298 
299 	return 0;
300 }
301 
302 static int max9286_i2c_mux_init(struct max9286_priv *priv)
303 {
304 	struct max9286_source *source;
305 	int ret;
306 
307 	if (!i2c_check_functionality(priv->client->adapter,
308 				     I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
309 		return -ENODEV;
310 
311 	priv->mux = i2c_mux_alloc(priv->client->adapter, &priv->client->dev,
312 				  priv->nsources, 0, I2C_MUX_LOCKED,
313 				  max9286_i2c_mux_select, NULL);
314 	if (!priv->mux)
315 		return -ENOMEM;
316 
317 	priv->mux->priv = priv;
318 
319 	for_each_source(priv, source) {
320 		unsigned int index = to_index(priv, source);
321 
322 		ret = i2c_mux_add_adapter(priv->mux, 0, index, 0);
323 		if (ret < 0)
324 			goto error;
325 	}
326 
327 	return 0;
328 
329 error:
330 	i2c_mux_del_adapters(priv->mux);
331 	return ret;
332 }
333 
334 static void max9286_configure_i2c(struct max9286_priv *priv, bool localack)
335 {
336 	u8 config = MAX9286_I2CSLVSH_469NS_234NS | MAX9286_I2CSLVTO_1024US |
337 		    MAX9286_I2CMSTBT_105KBPS;
338 
339 	if (localack)
340 		config |= MAX9286_I2CLOCACK;
341 
342 	max9286_write(priv, 0x34, config);
343 	usleep_range(3000, 5000);
344 }
345 
346 static void max9286_reverse_channel_setup(struct max9286_priv *priv,
347 					  unsigned int chan_amplitude)
348 {
349 	u8 chan_config;
350 
351 	if (priv->rev_chan_mv == chan_amplitude)
352 		return;
353 
354 	priv->rev_chan_mv = chan_amplitude;
355 
356 	/* Reverse channel transmission time: default to 1. */
357 	chan_config = MAX9286_REV_TRF(1);
358 
359 	/*
360 	 * Reverse channel setup.
361 	 *
362 	 * - Enable custom reverse channel configuration (through register 0x3f)
363 	 *   and set the first pulse length to 35 clock cycles.
364 	 * - Adjust reverse channel amplitude: values > 130 are programmed
365 	 *   using the additional +100mV REV_AMP_X boost flag
366 	 */
367 	max9286_write(priv, 0x3f, MAX9286_EN_REV_CFG | MAX9286_REV_FLEN(35));
368 
369 	if (chan_amplitude > 100) {
370 		/* It is not possible to express values (100 < x < 130) */
371 		chan_amplitude = max(30U, chan_amplitude - 100);
372 		chan_config |= MAX9286_REV_AMP_X;
373 	}
374 	max9286_write(priv, 0x3b, chan_config | MAX9286_REV_AMP(chan_amplitude));
375 	usleep_range(2000, 2500);
376 }
377 
378 /*
379  * max9286_check_video_links() - Make sure video links are detected and locked
380  *
381  * Performs safety checks on video link status. Make sure they are detected
382  * and all enabled links are locked.
383  *
384  * Returns 0 for success, -EIO for errors.
385  */
386 static int max9286_check_video_links(struct max9286_priv *priv)
387 {
388 	unsigned int i;
389 	int ret;
390 
391 	/*
392 	 * Make sure valid video links are detected.
393 	 * The delay is not characterized in de-serializer manual, wait up
394 	 * to 5 ms.
395 	 */
396 	for (i = 0; i < 10; i++) {
397 		ret = max9286_read(priv, 0x49);
398 		if (ret < 0)
399 			return -EIO;
400 
401 		if ((ret & MAX9286_VIDEO_DETECT_MASK) == priv->source_mask)
402 			break;
403 
404 		usleep_range(350, 500);
405 	}
406 
407 	if (i == 10) {
408 		dev_err(&priv->client->dev,
409 			"Unable to detect video links: 0x%02x\n", ret);
410 		return -EIO;
411 	}
412 
413 	/* Make sure all enabled links are locked (4ms max). */
414 	for (i = 0; i < 10; i++) {
415 		ret = max9286_read(priv, 0x27);
416 		if (ret < 0)
417 			return -EIO;
418 
419 		if (ret & MAX9286_LOCKED)
420 			break;
421 
422 		usleep_range(350, 450);
423 	}
424 
425 	if (i == 10) {
426 		dev_err(&priv->client->dev, "Not all enabled links locked\n");
427 		return -EIO;
428 	}
429 
430 	return 0;
431 }
432 
433 /*
434  * max9286_check_config_link() - Detect and wait for configuration links
435  *
436  * Determine if the configuration channel is up and settled for a link.
437  *
438  * Returns 0 for success, -EIO for errors.
439  */
440 static int max9286_check_config_link(struct max9286_priv *priv,
441 				     unsigned int source_mask)
442 {
443 	unsigned int conflink_mask = (source_mask & 0x0f) << 4;
444 	unsigned int i;
445 	int ret;
446 
447 	/*
448 	 * Make sure requested configuration links are detected.
449 	 * The delay is not characterized in the chip manual: wait up
450 	 * to 5 milliseconds.
451 	 */
452 	for (i = 0; i < 10; i++) {
453 		ret = max9286_read(priv, 0x49);
454 		if (ret < 0)
455 			return -EIO;
456 
457 		ret &= 0xf0;
458 		if (ret == conflink_mask)
459 			break;
460 
461 		usleep_range(350, 500);
462 	}
463 
464 	if (ret != conflink_mask) {
465 		dev_err(&priv->client->dev,
466 			"Unable to detect configuration links: 0x%02x expected 0x%02x\n",
467 			ret, conflink_mask);
468 		return -EIO;
469 	}
470 
471 	dev_info(&priv->client->dev,
472 		 "Successfully detected configuration links after %u loops: 0x%02x\n",
473 		 i, conflink_mask);
474 
475 	return 0;
476 }
477 
478 /* -----------------------------------------------------------------------------
479  * V4L2 Subdev
480  */
481 
482 static int max9286_set_pixelrate(struct max9286_priv *priv)
483 {
484 	struct max9286_source *source = NULL;
485 	u64 pixelrate = 0;
486 
487 	for_each_source(priv, source) {
488 		struct v4l2_ctrl *ctrl;
489 		u64 source_rate = 0;
490 
491 		/* Pixel rate is mandatory to be reported by sources. */
492 		ctrl = v4l2_ctrl_find(source->sd->ctrl_handler,
493 				      V4L2_CID_PIXEL_RATE);
494 		if (!ctrl) {
495 			pixelrate = 0;
496 			break;
497 		}
498 
499 		/* All source must report the same pixel rate. */
500 		source_rate = v4l2_ctrl_g_ctrl_int64(ctrl);
501 		if (!pixelrate) {
502 			pixelrate = source_rate;
503 		} else if (pixelrate != source_rate) {
504 			dev_err(&priv->client->dev,
505 				"Unable to calculate pixel rate\n");
506 			return -EINVAL;
507 		}
508 	}
509 
510 	if (!pixelrate) {
511 		dev_err(&priv->client->dev,
512 			"No pixel rate control available in sources\n");
513 		return -EINVAL;
514 	}
515 
516 	/*
517 	 * The CSI-2 transmitter pixel rate is the single source rate multiplied
518 	 * by the number of available sources.
519 	 */
520 	return v4l2_ctrl_s_ctrl_int64(priv->pixelrate,
521 				      pixelrate * priv->nsources);
522 }
523 
524 static int max9286_notify_bound(struct v4l2_async_notifier *notifier,
525 				struct v4l2_subdev *subdev,
526 				struct v4l2_async_subdev *asd)
527 {
528 	struct max9286_priv *priv = sd_to_max9286(notifier->sd);
529 	struct max9286_source *source = to_max9286_asd(asd)->source;
530 	unsigned int index = to_index(priv, source);
531 	unsigned int src_pad;
532 	int ret;
533 
534 	ret = media_entity_get_fwnode_pad(&subdev->entity,
535 					  source->fwnode,
536 					  MEDIA_PAD_FL_SOURCE);
537 	if (ret < 0) {
538 		dev_err(&priv->client->dev,
539 			"Failed to find pad for %s\n", subdev->name);
540 		return ret;
541 	}
542 
543 	priv->bound_sources |= BIT(index);
544 	source->sd = subdev;
545 	src_pad = ret;
546 
547 	ret = media_create_pad_link(&source->sd->entity, src_pad,
548 				    &priv->sd.entity, index,
549 				    MEDIA_LNK_FL_ENABLED |
550 				    MEDIA_LNK_FL_IMMUTABLE);
551 	if (ret) {
552 		dev_err(&priv->client->dev,
553 			"Unable to link %s:%u -> %s:%u\n",
554 			source->sd->name, src_pad, priv->sd.name, index);
555 		return ret;
556 	}
557 
558 	dev_dbg(&priv->client->dev, "Bound %s pad: %u on index %u\n",
559 		subdev->name, src_pad, index);
560 
561 	/*
562 	 * As we register a subdev notifiers we won't get a .complete() callback
563 	 * here, so we have to use bound_sources to identify when all remote
564 	 * serializers have probed.
565 	 */
566 	if (priv->bound_sources != priv->source_mask)
567 		return 0;
568 
569 	/*
570 	 * All enabled sources have probed and enabled their reverse control
571 	 * channels:
572 	 *
573 	 * - Increase the reverse channel amplitude to compensate for the
574 	 *   remote ends high threshold
575 	 * - Verify all configuration links are properly detected
576 	 * - Disable auto-ack as communication on the control channel are now
577 	 *   stable.
578 	 */
579 	max9286_reverse_channel_setup(priv, MAX9286_REV_AMP_HIGH);
580 	max9286_check_config_link(priv, priv->source_mask);
581 	max9286_configure_i2c(priv, false);
582 
583 	return max9286_set_pixelrate(priv);
584 }
585 
586 static void max9286_notify_unbind(struct v4l2_async_notifier *notifier,
587 				  struct v4l2_subdev *subdev,
588 				  struct v4l2_async_subdev *asd)
589 {
590 	struct max9286_priv *priv = sd_to_max9286(notifier->sd);
591 	struct max9286_source *source = to_max9286_asd(asd)->source;
592 	unsigned int index = to_index(priv, source);
593 
594 	source->sd = NULL;
595 	priv->bound_sources &= ~BIT(index);
596 }
597 
598 static const struct v4l2_async_notifier_operations max9286_notify_ops = {
599 	.bound = max9286_notify_bound,
600 	.unbind = max9286_notify_unbind,
601 };
602 
603 static int max9286_v4l2_notifier_register(struct max9286_priv *priv)
604 {
605 	struct device *dev = &priv->client->dev;
606 	struct max9286_source *source = NULL;
607 	int ret;
608 
609 	if (!priv->nsources)
610 		return 0;
611 
612 	v4l2_async_nf_init(&priv->notifier);
613 
614 	for_each_source(priv, source) {
615 		unsigned int i = to_index(priv, source);
616 		struct max9286_asd *mas;
617 
618 		mas = v4l2_async_nf_add_fwnode(&priv->notifier, source->fwnode,
619 					       struct max9286_asd);
620 		if (IS_ERR(mas)) {
621 			dev_err(dev, "Failed to add subdev for source %u: %ld",
622 				i, PTR_ERR(mas));
623 			v4l2_async_nf_cleanup(&priv->notifier);
624 			return PTR_ERR(mas);
625 		}
626 
627 		mas->source = source;
628 	}
629 
630 	priv->notifier.ops = &max9286_notify_ops;
631 
632 	ret = v4l2_async_subdev_nf_register(&priv->sd, &priv->notifier);
633 	if (ret) {
634 		dev_err(dev, "Failed to register subdev_notifier");
635 		v4l2_async_nf_cleanup(&priv->notifier);
636 		return ret;
637 	}
638 
639 	return 0;
640 }
641 
642 static void max9286_v4l2_notifier_unregister(struct max9286_priv *priv)
643 {
644 	if (!priv->nsources)
645 		return;
646 
647 	v4l2_async_nf_unregister(&priv->notifier);
648 	v4l2_async_nf_cleanup(&priv->notifier);
649 }
650 
651 static int max9286_s_stream(struct v4l2_subdev *sd, int enable)
652 {
653 	struct max9286_priv *priv = sd_to_max9286(sd);
654 	struct max9286_source *source;
655 	unsigned int i;
656 	bool sync = false;
657 	int ret;
658 
659 	if (enable) {
660 		/*
661 		 * The frame sync between cameras is transmitted across the
662 		 * reverse channel as GPIO. We must open all channels while
663 		 * streaming to allow this synchronisation signal to be shared.
664 		 */
665 		max9286_i2c_mux_open(priv);
666 
667 		/* Start all cameras. */
668 		for_each_source(priv, source) {
669 			ret = v4l2_subdev_call(source->sd, video, s_stream, 1);
670 			if (ret)
671 				return ret;
672 		}
673 
674 		ret = max9286_check_video_links(priv);
675 		if (ret)
676 			return ret;
677 
678 		/*
679 		 * Wait until frame synchronization is locked.
680 		 *
681 		 * Manual says frame sync locking should take ~6 VTS.
682 		 * From practical experience at least 8 are required. Give
683 		 * 12 complete frames time (~400ms at 30 fps) to achieve frame
684 		 * locking before returning error.
685 		 */
686 		for (i = 0; i < 40; i++) {
687 			if (max9286_read(priv, 0x31) & MAX9286_FSYNC_LOCKED) {
688 				sync = true;
689 				break;
690 			}
691 			usleep_range(9000, 11000);
692 		}
693 
694 		if (!sync) {
695 			dev_err(&priv->client->dev,
696 				"Failed to get frame synchronization\n");
697 			return -EXDEV; /* Invalid cross-device link */
698 		}
699 
700 		/*
701 		 * Enable CSI output, VC set according to link number.
702 		 * Bit 7 must be set (chip manual says it's 0 and reserved).
703 		 */
704 		max9286_write(priv, 0x15, 0x80 | MAX9286_VCTYPE |
705 			      MAX9286_CSIOUTEN | MAX9286_0X15_RESV);
706 	} else {
707 		max9286_write(priv, 0x15, MAX9286_VCTYPE | MAX9286_0X15_RESV);
708 
709 		/* Stop all cameras. */
710 		for_each_source(priv, source)
711 			v4l2_subdev_call(source->sd, video, s_stream, 0);
712 
713 		max9286_i2c_mux_close(priv);
714 	}
715 
716 	return 0;
717 }
718 
719 static int max9286_enum_mbus_code(struct v4l2_subdev *sd,
720 				  struct v4l2_subdev_state *sd_state,
721 				  struct v4l2_subdev_mbus_code_enum *code)
722 {
723 	if (code->pad || code->index > 0)
724 		return -EINVAL;
725 
726 	code->code = MEDIA_BUS_FMT_UYVY8_1X16;
727 
728 	return 0;
729 }
730 
731 static struct v4l2_mbus_framefmt *
732 max9286_get_pad_format(struct max9286_priv *priv,
733 		       struct v4l2_subdev_state *sd_state,
734 		       unsigned int pad, u32 which)
735 {
736 	switch (which) {
737 	case V4L2_SUBDEV_FORMAT_TRY:
738 		return v4l2_subdev_get_try_format(&priv->sd, sd_state, pad);
739 	case V4L2_SUBDEV_FORMAT_ACTIVE:
740 		return &priv->fmt[pad];
741 	default:
742 		return NULL;
743 	}
744 }
745 
746 static int max9286_set_fmt(struct v4l2_subdev *sd,
747 			   struct v4l2_subdev_state *sd_state,
748 			   struct v4l2_subdev_format *format)
749 {
750 	struct max9286_priv *priv = sd_to_max9286(sd);
751 	struct v4l2_mbus_framefmt *cfg_fmt;
752 
753 	if (format->pad == MAX9286_SRC_PAD)
754 		return -EINVAL;
755 
756 	/* Refuse non YUV422 formats as we hardcode DT to 8 bit YUV422 */
757 	switch (format->format.code) {
758 	case MEDIA_BUS_FMT_UYVY8_1X16:
759 	case MEDIA_BUS_FMT_VYUY8_1X16:
760 	case MEDIA_BUS_FMT_YUYV8_1X16:
761 	case MEDIA_BUS_FMT_YVYU8_1X16:
762 		break;
763 	default:
764 		format->format.code = MEDIA_BUS_FMT_UYVY8_1X16;
765 		break;
766 	}
767 
768 	cfg_fmt = max9286_get_pad_format(priv, sd_state, format->pad,
769 					 format->which);
770 	if (!cfg_fmt)
771 		return -EINVAL;
772 
773 	mutex_lock(&priv->mutex);
774 	*cfg_fmt = format->format;
775 	mutex_unlock(&priv->mutex);
776 
777 	return 0;
778 }
779 
780 static int max9286_get_fmt(struct v4l2_subdev *sd,
781 			   struct v4l2_subdev_state *sd_state,
782 			   struct v4l2_subdev_format *format)
783 {
784 	struct max9286_priv *priv = sd_to_max9286(sd);
785 	struct v4l2_mbus_framefmt *cfg_fmt;
786 	unsigned int pad = format->pad;
787 
788 	/*
789 	 * Multiplexed Stream Support: Support link validation by returning the
790 	 * format of the first bound link. All links must have the same format,
791 	 * as we do not support mixing and matching of cameras connected to the
792 	 * max9286.
793 	 */
794 	if (pad == MAX9286_SRC_PAD)
795 		pad = __ffs(priv->bound_sources);
796 
797 	cfg_fmt = max9286_get_pad_format(priv, sd_state, pad, format->which);
798 	if (!cfg_fmt)
799 		return -EINVAL;
800 
801 	mutex_lock(&priv->mutex);
802 	format->format = *cfg_fmt;
803 	mutex_unlock(&priv->mutex);
804 
805 	return 0;
806 }
807 
808 static const struct v4l2_subdev_video_ops max9286_video_ops = {
809 	.s_stream	= max9286_s_stream,
810 };
811 
812 static const struct v4l2_subdev_pad_ops max9286_pad_ops = {
813 	.enum_mbus_code = max9286_enum_mbus_code,
814 	.get_fmt	= max9286_get_fmt,
815 	.set_fmt	= max9286_set_fmt,
816 };
817 
818 static const struct v4l2_subdev_ops max9286_subdev_ops = {
819 	.video		= &max9286_video_ops,
820 	.pad		= &max9286_pad_ops,
821 };
822 
823 static void max9286_init_format(struct v4l2_mbus_framefmt *fmt)
824 {
825 	fmt->width		= 1280;
826 	fmt->height		= 800;
827 	fmt->code		= MEDIA_BUS_FMT_UYVY8_1X16;
828 	fmt->colorspace		= V4L2_COLORSPACE_SRGB;
829 	fmt->field		= V4L2_FIELD_NONE;
830 	fmt->ycbcr_enc		= V4L2_YCBCR_ENC_DEFAULT;
831 	fmt->quantization	= V4L2_QUANTIZATION_DEFAULT;
832 	fmt->xfer_func		= V4L2_XFER_FUNC_DEFAULT;
833 }
834 
835 static int max9286_open(struct v4l2_subdev *subdev, struct v4l2_subdev_fh *fh)
836 {
837 	struct v4l2_mbus_framefmt *format;
838 	unsigned int i;
839 
840 	for (i = 0; i < MAX9286_N_SINKS; i++) {
841 		format = v4l2_subdev_get_try_format(subdev, fh->state, i);
842 		max9286_init_format(format);
843 	}
844 
845 	return 0;
846 }
847 
848 static const struct v4l2_subdev_internal_ops max9286_subdev_internal_ops = {
849 	.open = max9286_open,
850 };
851 
852 static const struct media_entity_operations max9286_media_ops = {
853 	.link_validate = v4l2_subdev_link_validate
854 };
855 
856 static int max9286_s_ctrl(struct v4l2_ctrl *ctrl)
857 {
858 	switch (ctrl->id) {
859 	case V4L2_CID_PIXEL_RATE:
860 		return 0;
861 	default:
862 		return -EINVAL;
863 	}
864 }
865 
866 static const struct v4l2_ctrl_ops max9286_ctrl_ops = {
867 	.s_ctrl = max9286_s_ctrl,
868 };
869 
870 static int max9286_v4l2_register(struct max9286_priv *priv)
871 {
872 	struct device *dev = &priv->client->dev;
873 	struct fwnode_handle *ep;
874 	int ret;
875 	int i;
876 
877 	/* Register v4l2 async notifiers for connected Camera subdevices */
878 	ret = max9286_v4l2_notifier_register(priv);
879 	if (ret) {
880 		dev_err(dev, "Unable to register V4L2 async notifiers\n");
881 		return ret;
882 	}
883 
884 	/* Configure V4L2 for the MAX9286 itself */
885 
886 	for (i = 0; i < MAX9286_N_SINKS; i++)
887 		max9286_init_format(&priv->fmt[i]);
888 
889 	v4l2_i2c_subdev_init(&priv->sd, priv->client, &max9286_subdev_ops);
890 	priv->sd.internal_ops = &max9286_subdev_internal_ops;
891 	priv->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
892 
893 	v4l2_ctrl_handler_init(&priv->ctrls, 1);
894 	priv->pixelrate = v4l2_ctrl_new_std(&priv->ctrls,
895 					    &max9286_ctrl_ops,
896 					    V4L2_CID_PIXEL_RATE,
897 					    1, INT_MAX, 1, 50000000);
898 
899 	priv->sd.ctrl_handler = &priv->ctrls;
900 	ret = priv->ctrls.error;
901 	if (ret)
902 		goto err_async;
903 
904 	priv->sd.entity.function = MEDIA_ENT_F_VID_IF_BRIDGE;
905 	priv->sd.entity.ops = &max9286_media_ops;
906 
907 	priv->pads[MAX9286_SRC_PAD].flags = MEDIA_PAD_FL_SOURCE;
908 	for (i = 0; i < MAX9286_SRC_PAD; i++)
909 		priv->pads[i].flags = MEDIA_PAD_FL_SINK;
910 	ret = media_entity_pads_init(&priv->sd.entity, MAX9286_N_PADS,
911 				     priv->pads);
912 	if (ret)
913 		goto err_async;
914 
915 	ep = fwnode_graph_get_endpoint_by_id(dev_fwnode(dev), MAX9286_SRC_PAD,
916 					     0, 0);
917 	if (!ep) {
918 		dev_err(dev, "Unable to retrieve endpoint on \"port@4\"\n");
919 		ret = -ENOENT;
920 		goto err_async;
921 	}
922 	priv->sd.fwnode = ep;
923 
924 	ret = v4l2_async_register_subdev(&priv->sd);
925 	if (ret < 0) {
926 		dev_err(dev, "Unable to register subdevice\n");
927 		goto err_put_node;
928 	}
929 
930 	return 0;
931 
932 err_put_node:
933 	fwnode_handle_put(ep);
934 err_async:
935 	max9286_v4l2_notifier_unregister(priv);
936 
937 	return ret;
938 }
939 
940 static void max9286_v4l2_unregister(struct max9286_priv *priv)
941 {
942 	fwnode_handle_put(priv->sd.fwnode);
943 	v4l2_async_unregister_subdev(&priv->sd);
944 	max9286_v4l2_notifier_unregister(priv);
945 }
946 
947 /* -----------------------------------------------------------------------------
948  * Probe/Remove
949  */
950 
951 static int max9286_setup(struct max9286_priv *priv)
952 {
953 	/*
954 	 * Link ordering values for all enabled links combinations. Orders must
955 	 * be assigned sequentially from 0 to the number of enabled links
956 	 * without leaving any hole for disabled links. We thus assign orders to
957 	 * enabled links first, and use the remaining order values for disabled
958 	 * links are all links must have a different order value;
959 	 */
960 	static const u8 link_order[] = {
961 		(3 << 6) | (2 << 4) | (1 << 2) | (0 << 0), /* xxxx */
962 		(3 << 6) | (2 << 4) | (1 << 2) | (0 << 0), /* xxx0 */
963 		(3 << 6) | (2 << 4) | (0 << 2) | (1 << 0), /* xx0x */
964 		(3 << 6) | (2 << 4) | (1 << 2) | (0 << 0), /* xx10 */
965 		(3 << 6) | (0 << 4) | (2 << 2) | (1 << 0), /* x0xx */
966 		(3 << 6) | (1 << 4) | (2 << 2) | (0 << 0), /* x1x0 */
967 		(3 << 6) | (1 << 4) | (0 << 2) | (2 << 0), /* x10x */
968 		(3 << 6) | (1 << 4) | (1 << 2) | (0 << 0), /* x210 */
969 		(0 << 6) | (3 << 4) | (2 << 2) | (1 << 0), /* 0xxx */
970 		(1 << 6) | (3 << 4) | (2 << 2) | (0 << 0), /* 1xx0 */
971 		(1 << 6) | (3 << 4) | (0 << 2) | (2 << 0), /* 1x0x */
972 		(2 << 6) | (3 << 4) | (1 << 2) | (0 << 0), /* 2x10 */
973 		(1 << 6) | (0 << 4) | (3 << 2) | (2 << 0), /* 10xx */
974 		(2 << 6) | (1 << 4) | (3 << 2) | (0 << 0), /* 21x0 */
975 		(2 << 6) | (1 << 4) | (0 << 2) | (3 << 0), /* 210x */
976 		(3 << 6) | (2 << 4) | (1 << 2) | (0 << 0), /* 3210 */
977 	};
978 
979 	/*
980 	 * Set the I2C bus speed.
981 	 *
982 	 * Enable I2C Local Acknowledge during the probe sequences of the camera
983 	 * only. This should be disabled after the mux is initialised.
984 	 */
985 	max9286_configure_i2c(priv, true);
986 	max9286_reverse_channel_setup(priv, priv->init_rev_chan_mv);
987 
988 	/*
989 	 * Enable GMSL links, mask unused ones and autodetect link
990 	 * used as CSI clock source.
991 	 */
992 	max9286_write(priv, 0x00, MAX9286_MSTLINKSEL_AUTO | priv->route_mask);
993 	max9286_write(priv, 0x0b, link_order[priv->route_mask]);
994 	max9286_write(priv, 0x69, (0xf & ~priv->route_mask));
995 
996 	/*
997 	 * Video format setup:
998 	 * Disable CSI output, VC is set according to Link number.
999 	 */
1000 	max9286_write(priv, 0x15, MAX9286_VCTYPE | MAX9286_0X15_RESV);
1001 
1002 	/* Enable CSI-2 Lane D0-D3 only, DBL mode, YUV422 8-bit. */
1003 	max9286_write(priv, 0x12, MAX9286_CSIDBL | MAX9286_DBL |
1004 		      MAX9286_CSILANECNT(priv->csi2_data_lanes) |
1005 		      MAX9286_DATATYPE_YUV422_8BIT);
1006 
1007 	/* Automatic: FRAMESYNC taken from the slowest Link. */
1008 	max9286_write(priv, 0x01, MAX9286_FSYNCMODE_INT_HIZ |
1009 		      MAX9286_FSYNCMETH_AUTO);
1010 
1011 	/* Enable HS/VS encoding, use D14/15 for HS/VS, invert VS. */
1012 	max9286_write(priv, 0x0c, MAX9286_HVEN | MAX9286_INVVS |
1013 		      MAX9286_HVSRC_D14);
1014 
1015 	/*
1016 	 * The overlap window seems to provide additional validation by tracking
1017 	 * the delay between vsync and frame sync, generating an error if the
1018 	 * delay is bigger than the programmed window, though it's not yet clear
1019 	 * what value should be set.
1020 	 *
1021 	 * As it's an optional value and can be disabled, we do so by setting
1022 	 * a 0 overlap value.
1023 	 */
1024 	max9286_write(priv, 0x63, 0);
1025 	max9286_write(priv, 0x64, 0);
1026 
1027 	/*
1028 	 * Wait for 2ms to allow the link to resynchronize after the
1029 	 * configuration change.
1030 	 */
1031 	usleep_range(2000, 5000);
1032 
1033 	return 0;
1034 }
1035 
1036 static int max9286_gpio_set(struct max9286_priv *priv, unsigned int offset,
1037 			    int value)
1038 {
1039 	if (value)
1040 		priv->gpio_state |= BIT(offset);
1041 	else
1042 		priv->gpio_state &= ~BIT(offset);
1043 
1044 	return max9286_write(priv, 0x0f,
1045 			     MAX9286_0X0F_RESERVED | priv->gpio_state);
1046 }
1047 
1048 static void max9286_gpiochip_set(struct gpio_chip *chip,
1049 				 unsigned int offset, int value)
1050 {
1051 	struct max9286_priv *priv = gpiochip_get_data(chip);
1052 
1053 	max9286_gpio_set(priv, offset, value);
1054 }
1055 
1056 static int max9286_gpiochip_get(struct gpio_chip *chip, unsigned int offset)
1057 {
1058 	struct max9286_priv *priv = gpiochip_get_data(chip);
1059 
1060 	return priv->gpio_state & BIT(offset);
1061 }
1062 
1063 static int max9286_register_gpio(struct max9286_priv *priv)
1064 {
1065 	struct device *dev = &priv->client->dev;
1066 	struct gpio_chip *gpio = &priv->gpio;
1067 	int ret;
1068 
1069 	/* Configure the GPIO */
1070 	gpio->label = dev_name(dev);
1071 	gpio->parent = dev;
1072 	gpio->owner = THIS_MODULE;
1073 	gpio->ngpio = 2;
1074 	gpio->base = -1;
1075 	gpio->set = max9286_gpiochip_set;
1076 	gpio->get = max9286_gpiochip_get;
1077 	gpio->can_sleep = true;
1078 
1079 	ret = devm_gpiochip_add_data(dev, gpio, priv);
1080 	if (ret)
1081 		dev_err(dev, "Unable to create gpio_chip\n");
1082 
1083 	return ret;
1084 }
1085 
1086 static int max9286_parse_gpios(struct max9286_priv *priv)
1087 {
1088 	struct device *dev = &priv->client->dev;
1089 	int ret;
1090 
1091 	/* GPIO values default to high */
1092 	priv->gpio_state = BIT(0) | BIT(1);
1093 
1094 	/*
1095 	 * Parse the "gpio-poc" vendor property. If the property is not
1096 	 * specified the camera power is controlled by a regulator.
1097 	 */
1098 	ret = of_property_read_u32_array(dev->of_node, "maxim,gpio-poc",
1099 					 priv->gpio_poc, 2);
1100 	if (ret == -EINVAL) {
1101 		/*
1102 		 * If gpio lines are not used for the camera power, register
1103 		 * a gpio controller for consumers.
1104 		 */
1105 		ret = max9286_register_gpio(priv);
1106 		if (ret)
1107 			return ret;
1108 
1109 		priv->regulator = devm_regulator_get(dev, "poc");
1110 		if (IS_ERR(priv->regulator)) {
1111 			return dev_err_probe(dev, PTR_ERR(priv->regulator),
1112 					     "Unable to get PoC regulator (%ld)\n",
1113 					     PTR_ERR(priv->regulator));
1114 		}
1115 
1116 		return 0;
1117 	}
1118 
1119 	/* If the property is specified make sure it is well formed. */
1120 	if (ret || priv->gpio_poc[0] > 1 ||
1121 	    (priv->gpio_poc[1] != GPIO_ACTIVE_HIGH &&
1122 	     priv->gpio_poc[1] != GPIO_ACTIVE_LOW)) {
1123 		dev_err(dev, "Invalid 'gpio-poc' property\n");
1124 		return -EINVAL;
1125 	}
1126 
1127 	return 0;
1128 }
1129 
1130 static int max9286_poc_enable(struct max9286_priv *priv, bool enable)
1131 {
1132 	int ret;
1133 
1134 	/* If the regulator is not available, use gpio to control power. */
1135 	if (!priv->regulator)
1136 		ret = max9286_gpio_set(priv, priv->gpio_poc[0],
1137 				       enable ^ priv->gpio_poc[1]);
1138 	else if (enable)
1139 		ret = regulator_enable(priv->regulator);
1140 	else
1141 		ret = regulator_disable(priv->regulator);
1142 
1143 	if (ret < 0)
1144 		dev_err(&priv->client->dev, "Unable to turn power %s\n",
1145 			enable ? "on" : "off");
1146 
1147 	return ret;
1148 }
1149 
1150 static int max9286_init(struct max9286_priv *priv)
1151 {
1152 	struct i2c_client *client = priv->client;
1153 	int ret;
1154 
1155 	ret = max9286_poc_enable(priv, true);
1156 	if (ret)
1157 		return ret;
1158 
1159 	ret = max9286_setup(priv);
1160 	if (ret) {
1161 		dev_err(&client->dev, "Unable to setup max9286\n");
1162 		goto err_poc_disable;
1163 	}
1164 
1165 	/*
1166 	 * Register all V4L2 interactions for the MAX9286 and notifiers for
1167 	 * any subdevices connected.
1168 	 */
1169 	ret = max9286_v4l2_register(priv);
1170 	if (ret) {
1171 		dev_err(&client->dev, "Failed to register with V4L2\n");
1172 		goto err_poc_disable;
1173 	}
1174 
1175 	ret = max9286_i2c_mux_init(priv);
1176 	if (ret) {
1177 		dev_err(&client->dev, "Unable to initialize I2C multiplexer\n");
1178 		goto err_v4l2_register;
1179 	}
1180 
1181 	/* Leave the mux channels disabled until they are selected. */
1182 	max9286_i2c_mux_close(priv);
1183 
1184 	return 0;
1185 
1186 err_v4l2_register:
1187 	max9286_v4l2_unregister(priv);
1188 err_poc_disable:
1189 	max9286_poc_enable(priv, false);
1190 
1191 	return ret;
1192 }
1193 
1194 static void max9286_cleanup_dt(struct max9286_priv *priv)
1195 {
1196 	struct max9286_source *source;
1197 
1198 	for_each_source(priv, source) {
1199 		fwnode_handle_put(source->fwnode);
1200 		source->fwnode = NULL;
1201 	}
1202 }
1203 
1204 static int max9286_parse_dt(struct max9286_priv *priv)
1205 {
1206 	struct device *dev = &priv->client->dev;
1207 	struct device_node *i2c_mux;
1208 	struct device_node *node = NULL;
1209 	unsigned int i2c_mux_mask = 0;
1210 	u32 reverse_channel_microvolt;
1211 
1212 	/* Balance the of_node_put() performed by of_find_node_by_name(). */
1213 	of_node_get(dev->of_node);
1214 	i2c_mux = of_find_node_by_name(dev->of_node, "i2c-mux");
1215 	if (!i2c_mux) {
1216 		dev_err(dev, "Failed to find i2c-mux node\n");
1217 		return -EINVAL;
1218 	}
1219 
1220 	/* Identify which i2c-mux channels are enabled */
1221 	for_each_child_of_node(i2c_mux, node) {
1222 		u32 id = 0;
1223 
1224 		of_property_read_u32(node, "reg", &id);
1225 		if (id >= MAX9286_NUM_GMSL)
1226 			continue;
1227 
1228 		if (!of_device_is_available(node)) {
1229 			dev_dbg(dev, "Skipping disabled I2C bus port %u\n", id);
1230 			continue;
1231 		}
1232 
1233 		i2c_mux_mask |= BIT(id);
1234 	}
1235 	of_node_put(node);
1236 	of_node_put(i2c_mux);
1237 
1238 	/* Parse the endpoints */
1239 	for_each_endpoint_of_node(dev->of_node, node) {
1240 		struct max9286_source *source;
1241 		struct of_endpoint ep;
1242 
1243 		of_graph_parse_endpoint(node, &ep);
1244 		dev_dbg(dev, "Endpoint %pOF on port %d",
1245 			ep.local_node, ep.port);
1246 
1247 		if (ep.port > MAX9286_NUM_GMSL) {
1248 			dev_err(dev, "Invalid endpoint %s on port %d",
1249 				of_node_full_name(ep.local_node), ep.port);
1250 			continue;
1251 		}
1252 
1253 		/* For the source endpoint just parse the bus configuration. */
1254 		if (ep.port == MAX9286_SRC_PAD) {
1255 			struct v4l2_fwnode_endpoint vep = {
1256 				.bus_type = V4L2_MBUS_CSI2_DPHY
1257 			};
1258 			int ret;
1259 
1260 			ret = v4l2_fwnode_endpoint_parse(
1261 					of_fwnode_handle(node), &vep);
1262 			if (ret) {
1263 				of_node_put(node);
1264 				return ret;
1265 			}
1266 
1267 			priv->csi2_data_lanes =
1268 				vep.bus.mipi_csi2.num_data_lanes;
1269 
1270 			continue;
1271 		}
1272 
1273 		/* Skip if the corresponding GMSL link is unavailable. */
1274 		if (!(i2c_mux_mask & BIT(ep.port)))
1275 			continue;
1276 
1277 		if (priv->sources[ep.port].fwnode) {
1278 			dev_err(dev,
1279 				"Multiple port endpoints are not supported: %d",
1280 				ep.port);
1281 
1282 			continue;
1283 		}
1284 
1285 		source = &priv->sources[ep.port];
1286 		source->fwnode = fwnode_graph_get_remote_endpoint(
1287 						of_fwnode_handle(node));
1288 		if (!source->fwnode) {
1289 			dev_err(dev,
1290 				"Endpoint %pOF has no remote endpoint connection\n",
1291 				ep.local_node);
1292 
1293 			continue;
1294 		}
1295 
1296 		priv->source_mask |= BIT(ep.port);
1297 		priv->nsources++;
1298 	}
1299 	of_node_put(node);
1300 
1301 	/*
1302 	 * Parse the initial value of the reverse channel amplitude from
1303 	 * the firmware interface and convert it to millivolts.
1304 	 *
1305 	 * Default it to 170mV for backward compatibility with DTBs that do not
1306 	 * provide the property.
1307 	 */
1308 	if (of_property_read_u32(dev->of_node,
1309 				 "maxim,reverse-channel-microvolt",
1310 				 &reverse_channel_microvolt))
1311 		priv->init_rev_chan_mv = 170;
1312 	else
1313 		priv->init_rev_chan_mv = reverse_channel_microvolt / 1000U;
1314 
1315 	priv->route_mask = priv->source_mask;
1316 
1317 	return 0;
1318 }
1319 
1320 static int max9286_probe(struct i2c_client *client)
1321 {
1322 	struct max9286_priv *priv;
1323 	int ret;
1324 
1325 	priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
1326 	if (!priv)
1327 		return -ENOMEM;
1328 
1329 	mutex_init(&priv->mutex);
1330 
1331 	priv->client = client;
1332 
1333 	priv->gpiod_pwdn = devm_gpiod_get_optional(&client->dev, "enable",
1334 						   GPIOD_OUT_HIGH);
1335 	if (IS_ERR(priv->gpiod_pwdn))
1336 		return PTR_ERR(priv->gpiod_pwdn);
1337 
1338 	gpiod_set_consumer_name(priv->gpiod_pwdn, "max9286-pwdn");
1339 	gpiod_set_value_cansleep(priv->gpiod_pwdn, 1);
1340 
1341 	/* Wait at least 4ms before the I2C lines latch to the address */
1342 	if (priv->gpiod_pwdn)
1343 		usleep_range(4000, 5000);
1344 
1345 	/*
1346 	 * The MAX9286 starts by default with all ports enabled, we disable all
1347 	 * ports early to ensure that all channels are disabled if we error out
1348 	 * and keep the bus consistent.
1349 	 */
1350 	max9286_i2c_mux_close(priv);
1351 
1352 	/*
1353 	 * The MAX9286 initialises with auto-acknowledge enabled by default.
1354 	 * This can be invasive to other transactions on the same bus, so
1355 	 * disable it early. It will be enabled only as and when needed.
1356 	 */
1357 	max9286_configure_i2c(priv, false);
1358 
1359 	ret = max9286_parse_gpios(priv);
1360 	if (ret)
1361 		goto err_powerdown;
1362 
1363 	ret = max9286_parse_dt(priv);
1364 	if (ret)
1365 		goto err_powerdown;
1366 
1367 	ret = max9286_init(priv);
1368 	if (ret < 0)
1369 		goto err_cleanup_dt;
1370 
1371 	return 0;
1372 
1373 err_cleanup_dt:
1374 	max9286_cleanup_dt(priv);
1375 err_powerdown:
1376 	gpiod_set_value_cansleep(priv->gpiod_pwdn, 0);
1377 
1378 	return ret;
1379 }
1380 
1381 static void max9286_remove(struct i2c_client *client)
1382 {
1383 	struct max9286_priv *priv = sd_to_max9286(i2c_get_clientdata(client));
1384 
1385 	i2c_mux_del_adapters(priv->mux);
1386 
1387 	max9286_v4l2_unregister(priv);
1388 
1389 	max9286_poc_enable(priv, false);
1390 
1391 	gpiod_set_value_cansleep(priv->gpiod_pwdn, 0);
1392 
1393 	max9286_cleanup_dt(priv);
1394 }
1395 
1396 static const struct of_device_id max9286_dt_ids[] = {
1397 	{ .compatible = "maxim,max9286" },
1398 	{},
1399 };
1400 MODULE_DEVICE_TABLE(of, max9286_dt_ids);
1401 
1402 static struct i2c_driver max9286_i2c_driver = {
1403 	.driver	= {
1404 		.name		= "max9286",
1405 		.of_match_table	= of_match_ptr(max9286_dt_ids),
1406 	},
1407 	.probe_new	= max9286_probe,
1408 	.remove		= max9286_remove,
1409 };
1410 
1411 module_i2c_driver(max9286_i2c_driver);
1412 
1413 MODULE_DESCRIPTION("Maxim MAX9286 GMSL Deserializer Driver");
1414 MODULE_AUTHOR("Jacopo Mondi, Kieran Bingham, Laurent Pinchart, Niklas Söderlund, Vladimir Barinov");
1415 MODULE_LICENSE("GPL");
1416