xref: /openbmc/linux/drivers/media/i2c/max9286.c (revision 479965a2)
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_RAW12		(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_CSI_IMAGE_TYP		BIT(7)
85 #define MAX9286_VC(n)			((n) << 5)
86 #define MAX9286_VCTYPE			BIT(4)
87 #define MAX9286_CSIOUTEN		BIT(3)
88 #define MAX9286_SWP_ENDIAN		BIT(2)
89 #define MAX9286_EN_CCBSYB_CLK_STR	BIT(1)
90 #define MAX9286_EN_GPI_CCBSYB		BIT(0)
91 /* Register 0x1b */
92 #define MAX9286_SWITCHIN(n)		(1 << ((n) + 4))
93 #define MAX9286_ENEQ(n)			(1 << (n))
94 /* Register 0x1c */
95 #define MAX9286_HIGHIMM(n)		BIT((n) + 4)
96 #define MAX9286_I2CSEL			BIT(2)
97 #define MAX9286_HIBW			BIT(1)
98 #define MAX9286_BWS			BIT(0)
99 /* Register 0x27 */
100 #define MAX9286_LOCKED			BIT(7)
101 /* Register 0x31 */
102 #define MAX9286_FSYNC_LOCKED		BIT(6)
103 /* Register 0x34 */
104 #define MAX9286_I2CLOCACK		BIT(7)
105 #define MAX9286_I2CSLVSH_1046NS_469NS	(3 << 5)
106 #define MAX9286_I2CSLVSH_938NS_352NS	(2 << 5)
107 #define MAX9286_I2CSLVSH_469NS_234NS	(1 << 5)
108 #define MAX9286_I2CSLVSH_352NS_117NS	(0 << 5)
109 #define MAX9286_I2CMSTBT_837KBPS	(7 << 2)
110 #define MAX9286_I2CMSTBT_533KBPS	(6 << 2)
111 #define MAX9286_I2CMSTBT_339KBPS	(5 << 2)
112 #define MAX9286_I2CMSTBT_173KBPS	(4 << 2)
113 #define MAX9286_I2CMSTBT_105KBPS	(3 << 2)
114 #define MAX9286_I2CMSTBT_84KBPS		(2 << 2)
115 #define MAX9286_I2CMSTBT_28KBPS		(1 << 2)
116 #define MAX9286_I2CMSTBT_8KBPS		(0 << 2)
117 #define MAX9286_I2CSLVTO_NONE		(3 << 0)
118 #define MAX9286_I2CSLVTO_1024US		(2 << 0)
119 #define MAX9286_I2CSLVTO_256US		(1 << 0)
120 #define MAX9286_I2CSLVTO_64US		(0 << 0)
121 /* Register 0x3b */
122 #define MAX9286_REV_TRF(n)		((n) << 4)
123 #define MAX9286_REV_AMP(n)		((((n) - 30) / 10) << 1) /* in mV */
124 #define MAX9286_REV_AMP_X		BIT(0)
125 #define MAX9286_REV_AMP_HIGH		170
126 /* Register 0x3f */
127 #define MAX9286_EN_REV_CFG		BIT(6)
128 #define MAX9286_REV_FLEN(n)		((n) - 20)
129 /* Register 0x49 */
130 #define MAX9286_VIDEO_DETECT_MASK	0x0f
131 /* Register 0x69 */
132 #define MAX9286_LFLTBMONMASKED		BIT(7)
133 #define MAX9286_LOCKMONMASKED		BIT(6)
134 #define MAX9286_AUTOCOMBACKEN		BIT(5)
135 #define MAX9286_AUTOMASKEN		BIT(4)
136 #define MAX9286_MASKLINK(n)		((n) << 0)
137 
138 /*
139  * The sink and source pads are created to match the OF graph port numbers so
140  * that their indexes can be used interchangeably.
141  */
142 #define MAX9286_NUM_GMSL		4
143 #define MAX9286_N_SINKS			4
144 #define MAX9286_N_PADS			5
145 #define MAX9286_SRC_PAD			4
146 
147 struct max9286_format_info {
148 	u32 code;
149 	u8 datatype;
150 };
151 
152 struct max9286_i2c_speed {
153 	u32 rate;
154 	u8 mstbt;
155 };
156 
157 struct max9286_source {
158 	struct v4l2_subdev *sd;
159 	struct fwnode_handle *fwnode;
160 	struct regulator *regulator;
161 };
162 
163 struct max9286_asd {
164 	struct v4l2_async_connection base;
165 	struct max9286_source *source;
166 };
167 
168 static inline struct max9286_asd *
169 to_max9286_asd(struct v4l2_async_connection *asd)
170 {
171 	return container_of(asd, struct max9286_asd, base);
172 }
173 
174 struct max9286_priv {
175 	struct i2c_client *client;
176 	struct gpio_desc *gpiod_pwdn;
177 	struct v4l2_subdev sd;
178 	struct media_pad pads[MAX9286_N_PADS];
179 	struct regulator *regulator;
180 
181 	struct gpio_chip gpio;
182 	u8 gpio_state;
183 
184 	struct i2c_mux_core *mux;
185 	unsigned int mux_channel;
186 	bool mux_open;
187 
188 	/* The initial reverse control channel amplitude. */
189 	u32 init_rev_chan_mv;
190 	u32 rev_chan_mv;
191 	u8 i2c_mstbt;
192 	u32 bus_width;
193 
194 	bool use_gpio_poc;
195 	u32 gpio_poc[2];
196 
197 	struct v4l2_ctrl_handler ctrls;
198 	struct v4l2_ctrl *pixelrate_ctrl;
199 	unsigned int pixelrate;
200 
201 	struct v4l2_mbus_framefmt fmt[MAX9286_N_SINKS];
202 	struct v4l2_fract interval;
203 
204 	/* Protects controls and fmt structures */
205 	struct mutex mutex;
206 
207 	unsigned int nsources;
208 	unsigned int source_mask;
209 	unsigned int route_mask;
210 	unsigned int bound_sources;
211 	unsigned int csi2_data_lanes;
212 	struct max9286_source sources[MAX9286_NUM_GMSL];
213 	struct v4l2_async_notifier notifier;
214 };
215 
216 static struct max9286_source *next_source(struct max9286_priv *priv,
217 					  struct max9286_source *source)
218 {
219 	if (!source)
220 		source = &priv->sources[0];
221 	else
222 		source++;
223 
224 	for (; source < &priv->sources[MAX9286_NUM_GMSL]; source++) {
225 		if (source->fwnode)
226 			return source;
227 	}
228 
229 	return NULL;
230 }
231 
232 #define for_each_source(priv, source) \
233 	for ((source) = NULL; ((source) = next_source((priv), (source))); )
234 
235 #define to_index(priv, source) ((source) - &(priv)->sources[0])
236 
237 static inline struct max9286_priv *sd_to_max9286(struct v4l2_subdev *sd)
238 {
239 	return container_of(sd, struct max9286_priv, sd);
240 }
241 
242 static const struct max9286_format_info max9286_formats[] = {
243 	{
244 		.code = MEDIA_BUS_FMT_UYVY8_1X16,
245 		.datatype = MAX9286_DATATYPE_YUV422_8BIT,
246 	}, {
247 		.code = MEDIA_BUS_FMT_VYUY8_1X16,
248 		.datatype = MAX9286_DATATYPE_YUV422_8BIT,
249 	}, {
250 		.code = MEDIA_BUS_FMT_YUYV8_1X16,
251 		.datatype = MAX9286_DATATYPE_YUV422_8BIT,
252 	}, {
253 		.code = MEDIA_BUS_FMT_YVYU8_1X16,
254 		.datatype = MAX9286_DATATYPE_YUV422_8BIT,
255 	}, {
256 		.code = MEDIA_BUS_FMT_SBGGR12_1X12,
257 		.datatype = MAX9286_DATATYPE_RAW12,
258 	}, {
259 		.code = MEDIA_BUS_FMT_SGBRG12_1X12,
260 		.datatype = MAX9286_DATATYPE_RAW12,
261 	}, {
262 		.code = MEDIA_BUS_FMT_SGRBG12_1X12,
263 		.datatype = MAX9286_DATATYPE_RAW12,
264 	}, {
265 		.code = MEDIA_BUS_FMT_SRGGB12_1X12,
266 		.datatype = MAX9286_DATATYPE_RAW12,
267 	},
268 };
269 
270 static const struct max9286_i2c_speed max9286_i2c_speeds[] = {
271 	{ .rate =   8470, .mstbt = MAX9286_I2CMSTBT_8KBPS },
272 	{ .rate =  28300, .mstbt = MAX9286_I2CMSTBT_28KBPS },
273 	{ .rate =  84700, .mstbt = MAX9286_I2CMSTBT_84KBPS },
274 	{ .rate = 105000, .mstbt = MAX9286_I2CMSTBT_105KBPS },
275 	{ .rate = 173000, .mstbt = MAX9286_I2CMSTBT_173KBPS },
276 	{ .rate = 339000, .mstbt = MAX9286_I2CMSTBT_339KBPS },
277 	{ .rate = 533000, .mstbt = MAX9286_I2CMSTBT_533KBPS },
278 	{ .rate = 837000, .mstbt = MAX9286_I2CMSTBT_837KBPS },
279 };
280 
281 /* -----------------------------------------------------------------------------
282  * I2C IO
283  */
284 
285 static int max9286_read(struct max9286_priv *priv, u8 reg)
286 {
287 	int ret;
288 
289 	ret = i2c_smbus_read_byte_data(priv->client, reg);
290 	if (ret < 0)
291 		dev_err(&priv->client->dev,
292 			"%s: register 0x%02x read failed (%d)\n",
293 			__func__, reg, ret);
294 
295 	return ret;
296 }
297 
298 static int max9286_write(struct max9286_priv *priv, u8 reg, u8 val)
299 {
300 	int ret;
301 
302 	ret = i2c_smbus_write_byte_data(priv->client, reg, val);
303 	if (ret < 0)
304 		dev_err(&priv->client->dev,
305 			"%s: register 0x%02x write failed (%d)\n",
306 			__func__, reg, ret);
307 
308 	return ret;
309 }
310 
311 /* -----------------------------------------------------------------------------
312  * I2C Multiplexer
313  */
314 
315 static void max9286_i2c_mux_configure(struct max9286_priv *priv, u8 conf)
316 {
317 	max9286_write(priv, 0x0a, conf);
318 
319 	/*
320 	 * We must sleep after any change to the forward or reverse channel
321 	 * configuration.
322 	 */
323 	usleep_range(3000, 5000);
324 }
325 
326 static void max9286_i2c_mux_open(struct max9286_priv *priv)
327 {
328 	/* Open all channels on the MAX9286 */
329 	max9286_i2c_mux_configure(priv, 0xff);
330 
331 	priv->mux_open = true;
332 }
333 
334 static void max9286_i2c_mux_close(struct max9286_priv *priv)
335 {
336 	/*
337 	 * Ensure that both the forward and reverse channel are disabled on the
338 	 * mux, and that the channel ID is invalidated to ensure we reconfigure
339 	 * on the next max9286_i2c_mux_select() call.
340 	 */
341 	max9286_i2c_mux_configure(priv, 0x00);
342 
343 	priv->mux_open = false;
344 	priv->mux_channel = -1;
345 }
346 
347 static int max9286_i2c_mux_select(struct i2c_mux_core *muxc, u32 chan)
348 {
349 	struct max9286_priv *priv = i2c_mux_priv(muxc);
350 
351 	/* Channel select is disabled when configured in the opened state. */
352 	if (priv->mux_open)
353 		return 0;
354 
355 	if (priv->mux_channel == chan)
356 		return 0;
357 
358 	priv->mux_channel = chan;
359 
360 	max9286_i2c_mux_configure(priv, MAX9286_FWDCCEN(chan) |
361 					MAX9286_REVCCEN(chan));
362 
363 	return 0;
364 }
365 
366 static int max9286_i2c_mux_init(struct max9286_priv *priv)
367 {
368 	struct max9286_source *source;
369 	int ret;
370 
371 	if (!i2c_check_functionality(priv->client->adapter,
372 				     I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
373 		return -ENODEV;
374 
375 	priv->mux = i2c_mux_alloc(priv->client->adapter, &priv->client->dev,
376 				  priv->nsources, 0, I2C_MUX_LOCKED,
377 				  max9286_i2c_mux_select, NULL);
378 	if (!priv->mux)
379 		return -ENOMEM;
380 
381 	priv->mux->priv = priv;
382 
383 	for_each_source(priv, source) {
384 		unsigned int index = to_index(priv, source);
385 
386 		ret = i2c_mux_add_adapter(priv->mux, 0, index, 0);
387 		if (ret < 0)
388 			goto error;
389 	}
390 
391 	return 0;
392 
393 error:
394 	i2c_mux_del_adapters(priv->mux);
395 	return ret;
396 }
397 
398 static void max9286_configure_i2c(struct max9286_priv *priv, bool localack)
399 {
400 	u8 config = MAX9286_I2CSLVSH_469NS_234NS | MAX9286_I2CSLVTO_1024US |
401 		    priv->i2c_mstbt;
402 
403 	if (localack)
404 		config |= MAX9286_I2CLOCACK;
405 
406 	max9286_write(priv, 0x34, config);
407 	usleep_range(3000, 5000);
408 }
409 
410 static void max9286_reverse_channel_setup(struct max9286_priv *priv,
411 					  unsigned int chan_amplitude)
412 {
413 	u8 chan_config;
414 
415 	if (priv->rev_chan_mv == chan_amplitude)
416 		return;
417 
418 	priv->rev_chan_mv = chan_amplitude;
419 
420 	/* Reverse channel transmission time: default to 1. */
421 	chan_config = MAX9286_REV_TRF(1);
422 
423 	/*
424 	 * Reverse channel setup.
425 	 *
426 	 * - Enable custom reverse channel configuration (through register 0x3f)
427 	 *   and set the first pulse length to 35 clock cycles.
428 	 * - Adjust reverse channel amplitude: values > 130 are programmed
429 	 *   using the additional +100mV REV_AMP_X boost flag
430 	 */
431 	max9286_write(priv, 0x3f, MAX9286_EN_REV_CFG | MAX9286_REV_FLEN(35));
432 
433 	if (chan_amplitude > 100) {
434 		/* It is not possible to express values (100 < x < 130) */
435 		chan_amplitude = max(30U, chan_amplitude - 100);
436 		chan_config |= MAX9286_REV_AMP_X;
437 	}
438 	max9286_write(priv, 0x3b, chan_config | MAX9286_REV_AMP(chan_amplitude));
439 	usleep_range(2000, 2500);
440 }
441 
442 /*
443  * max9286_check_video_links() - Make sure video links are detected and locked
444  *
445  * Performs safety checks on video link status. Make sure they are detected
446  * and all enabled links are locked.
447  *
448  * Returns 0 for success, -EIO for errors.
449  */
450 static int max9286_check_video_links(struct max9286_priv *priv)
451 {
452 	unsigned int i;
453 	int ret;
454 
455 	/*
456 	 * Make sure valid video links are detected.
457 	 * The delay is not characterized in de-serializer manual, wait up
458 	 * to 5 ms.
459 	 */
460 	for (i = 0; i < 10; i++) {
461 		ret = max9286_read(priv, 0x49);
462 		if (ret < 0)
463 			return -EIO;
464 
465 		if ((ret & MAX9286_VIDEO_DETECT_MASK) == priv->source_mask)
466 			break;
467 
468 		usleep_range(350, 500);
469 	}
470 
471 	if (i == 10) {
472 		dev_err(&priv->client->dev,
473 			"Unable to detect video links: 0x%02x\n", ret);
474 		return -EIO;
475 	}
476 
477 	/* Make sure all enabled links are locked (4ms max). */
478 	for (i = 0; i < 10; i++) {
479 		ret = max9286_read(priv, 0x27);
480 		if (ret < 0)
481 			return -EIO;
482 
483 		if (ret & MAX9286_LOCKED)
484 			break;
485 
486 		usleep_range(350, 450);
487 	}
488 
489 	if (i == 10) {
490 		dev_err(&priv->client->dev, "Not all enabled links locked\n");
491 		return -EIO;
492 	}
493 
494 	return 0;
495 }
496 
497 /*
498  * max9286_check_config_link() - Detect and wait for configuration links
499  *
500  * Determine if the configuration channel is up and settled for a link.
501  *
502  * Returns 0 for success, -EIO for errors.
503  */
504 static int max9286_check_config_link(struct max9286_priv *priv,
505 				     unsigned int source_mask)
506 {
507 	unsigned int conflink_mask = (source_mask & 0x0f) << 4;
508 	unsigned int i;
509 	int ret;
510 
511 	/*
512 	 * Make sure requested configuration links are detected.
513 	 * The delay is not characterized in the chip manual: wait up
514 	 * to 5 milliseconds.
515 	 */
516 	for (i = 0; i < 10; i++) {
517 		ret = max9286_read(priv, 0x49);
518 		if (ret < 0)
519 			return -EIO;
520 
521 		ret &= 0xf0;
522 		if (ret == conflink_mask)
523 			break;
524 
525 		usleep_range(350, 500);
526 	}
527 
528 	if (ret != conflink_mask) {
529 		dev_err(&priv->client->dev,
530 			"Unable to detect configuration links: 0x%02x expected 0x%02x\n",
531 			ret, conflink_mask);
532 		return -EIO;
533 	}
534 
535 	dev_info(&priv->client->dev,
536 		 "Successfully detected configuration links after %u loops: 0x%02x\n",
537 		 i, conflink_mask);
538 
539 	return 0;
540 }
541 
542 static void max9286_set_video_format(struct max9286_priv *priv,
543 				     const struct v4l2_mbus_framefmt *format)
544 {
545 	const struct max9286_format_info *info = NULL;
546 	unsigned int i;
547 
548 	for (i = 0; i < ARRAY_SIZE(max9286_formats); ++i) {
549 		if (max9286_formats[i].code == format->code) {
550 			info = &max9286_formats[i];
551 			break;
552 		}
553 	}
554 
555 	if (WARN_ON(!info))
556 		return;
557 
558 	/*
559 	 * Video format setup: disable CSI output, set VC according to Link
560 	 * number, enable I2C clock stretching when CCBSY is low, enable CCBSY
561 	 * in external GPI-to-GPO mode.
562 	 */
563 	max9286_write(priv, 0x15, MAX9286_VCTYPE | MAX9286_EN_CCBSYB_CLK_STR |
564 		      MAX9286_EN_GPI_CCBSYB);
565 
566 	/* Enable CSI-2 Lane D0-D3 only, DBL mode. */
567 	max9286_write(priv, 0x12, MAX9286_CSIDBL | MAX9286_DBL |
568 		      MAX9286_CSILANECNT(priv->csi2_data_lanes) |
569 		      info->datatype);
570 
571 	/*
572 	 * Enable HS/VS encoding, use HS as line valid source, use D14/15 for
573 	 * HS/VS, invert VS.
574 	 */
575 	max9286_write(priv, 0x0c, MAX9286_HVEN | MAX9286_DESEL |
576 		      MAX9286_INVVS | MAX9286_HVSRC_D14);
577 }
578 
579 static void max9286_set_fsync_period(struct max9286_priv *priv)
580 {
581 	u32 fsync;
582 
583 	if (!priv->interval.numerator || !priv->interval.denominator) {
584 		/*
585 		 * Special case, a null interval enables automatic FRAMESYNC
586 		 * mode. FRAMESYNC is taken from the slowest link.
587 		 */
588 		max9286_write(priv, 0x01, MAX9286_FSYNCMODE_INT_HIZ |
589 			      MAX9286_FSYNCMETH_AUTO);
590 		return;
591 	}
592 
593 	/*
594 	 * Manual FRAMESYNC
595 	 *
596 	 * The FRAMESYNC generator is configured with a period expressed as a
597 	 * number of PCLK periods.
598 	 */
599 	fsync = div_u64((u64)priv->pixelrate * priv->interval.numerator,
600 			priv->interval.denominator);
601 
602 	dev_dbg(&priv->client->dev, "fsync period %u (pclk %u)\n", fsync,
603 		priv->pixelrate);
604 
605 	max9286_write(priv, 0x01, MAX9286_FSYNCMODE_INT_OUT |
606 		      MAX9286_FSYNCMETH_MANUAL);
607 
608 	max9286_write(priv, 0x06, (fsync >> 0) & 0xff);
609 	max9286_write(priv, 0x07, (fsync >> 8) & 0xff);
610 	max9286_write(priv, 0x08, (fsync >> 16) & 0xff);
611 }
612 
613 /* -----------------------------------------------------------------------------
614  * V4L2 Subdev
615  */
616 
617 static int max9286_set_pixelrate(struct max9286_priv *priv)
618 {
619 	struct max9286_source *source = NULL;
620 	u64 pixelrate = 0;
621 
622 	for_each_source(priv, source) {
623 		struct v4l2_ctrl *ctrl;
624 		u64 source_rate = 0;
625 
626 		/* Pixel rate is mandatory to be reported by sources. */
627 		ctrl = v4l2_ctrl_find(source->sd->ctrl_handler,
628 				      V4L2_CID_PIXEL_RATE);
629 		if (!ctrl) {
630 			pixelrate = 0;
631 			break;
632 		}
633 
634 		/* All source must report the same pixel rate. */
635 		source_rate = v4l2_ctrl_g_ctrl_int64(ctrl);
636 		if (!pixelrate) {
637 			pixelrate = source_rate;
638 		} else if (pixelrate != source_rate) {
639 			dev_err(&priv->client->dev,
640 				"Unable to calculate pixel rate\n");
641 			return -EINVAL;
642 		}
643 	}
644 
645 	if (!pixelrate) {
646 		dev_err(&priv->client->dev,
647 			"No pixel rate control available in sources\n");
648 		return -EINVAL;
649 	}
650 
651 	priv->pixelrate = pixelrate;
652 
653 	/*
654 	 * The CSI-2 transmitter pixel rate is the single source rate multiplied
655 	 * by the number of available sources.
656 	 */
657 	return v4l2_ctrl_s_ctrl_int64(priv->pixelrate_ctrl,
658 				      pixelrate * priv->nsources);
659 }
660 
661 static int max9286_notify_bound(struct v4l2_async_notifier *notifier,
662 				struct v4l2_subdev *subdev,
663 				struct v4l2_async_connection *asd)
664 {
665 	struct max9286_priv *priv = sd_to_max9286(notifier->sd);
666 	struct max9286_source *source = to_max9286_asd(asd)->source;
667 	unsigned int index = to_index(priv, source);
668 	unsigned int src_pad;
669 	int ret;
670 
671 	ret = media_entity_get_fwnode_pad(&subdev->entity,
672 					  source->fwnode,
673 					  MEDIA_PAD_FL_SOURCE);
674 	if (ret < 0) {
675 		dev_err(&priv->client->dev,
676 			"Failed to find pad for %s\n", subdev->name);
677 		return ret;
678 	}
679 
680 	priv->bound_sources |= BIT(index);
681 	source->sd = subdev;
682 	src_pad = ret;
683 
684 	ret = media_create_pad_link(&source->sd->entity, src_pad,
685 				    &priv->sd.entity, index,
686 				    MEDIA_LNK_FL_ENABLED |
687 				    MEDIA_LNK_FL_IMMUTABLE);
688 	if (ret) {
689 		dev_err(&priv->client->dev,
690 			"Unable to link %s:%u -> %s:%u\n",
691 			source->sd->name, src_pad, priv->sd.name, index);
692 		return ret;
693 	}
694 
695 	dev_dbg(&priv->client->dev, "Bound %s pad: %u on index %u\n",
696 		subdev->name, src_pad, index);
697 
698 	/*
699 	 * As we register a subdev notifiers we won't get a .complete() callback
700 	 * here, so we have to use bound_sources to identify when all remote
701 	 * serializers have probed.
702 	 */
703 	if (priv->bound_sources != priv->source_mask)
704 		return 0;
705 
706 	/*
707 	 * All enabled sources have probed and enabled their reverse control
708 	 * channels:
709 	 *
710 	 * - Increase the reverse channel amplitude to compensate for the
711 	 *   remote ends high threshold
712 	 * - Verify all configuration links are properly detected
713 	 * - Disable auto-ack as communication on the control channel are now
714 	 *   stable.
715 	 */
716 	max9286_reverse_channel_setup(priv, MAX9286_REV_AMP_HIGH);
717 	max9286_check_config_link(priv, priv->source_mask);
718 	max9286_configure_i2c(priv, false);
719 
720 	return max9286_set_pixelrate(priv);
721 }
722 
723 static void max9286_notify_unbind(struct v4l2_async_notifier *notifier,
724 				  struct v4l2_subdev *subdev,
725 				  struct v4l2_async_connection *asd)
726 {
727 	struct max9286_priv *priv = sd_to_max9286(notifier->sd);
728 	struct max9286_source *source = to_max9286_asd(asd)->source;
729 	unsigned int index = to_index(priv, source);
730 
731 	source->sd = NULL;
732 	priv->bound_sources &= ~BIT(index);
733 }
734 
735 static const struct v4l2_async_notifier_operations max9286_notify_ops = {
736 	.bound = max9286_notify_bound,
737 	.unbind = max9286_notify_unbind,
738 };
739 
740 static int max9286_v4l2_notifier_register(struct max9286_priv *priv)
741 {
742 	struct device *dev = &priv->client->dev;
743 	struct max9286_source *source = NULL;
744 	int ret;
745 
746 	if (!priv->nsources)
747 		return 0;
748 
749 	v4l2_async_subdev_nf_init(&priv->notifier, &priv->sd);
750 
751 	for_each_source(priv, source) {
752 		unsigned int i = to_index(priv, source);
753 		struct max9286_asd *mas;
754 
755 		mas = v4l2_async_nf_add_fwnode(&priv->notifier, source->fwnode,
756 					       struct max9286_asd);
757 		if (IS_ERR(mas)) {
758 			dev_err(dev, "Failed to add subdev for source %u: %ld",
759 				i, PTR_ERR(mas));
760 			v4l2_async_nf_cleanup(&priv->notifier);
761 			return PTR_ERR(mas);
762 		}
763 
764 		mas->source = source;
765 	}
766 
767 	priv->notifier.ops = &max9286_notify_ops;
768 
769 	ret = v4l2_async_nf_register(&priv->notifier);
770 	if (ret) {
771 		dev_err(dev, "Failed to register subdev_notifier");
772 		v4l2_async_nf_cleanup(&priv->notifier);
773 		return ret;
774 	}
775 
776 	return 0;
777 }
778 
779 static void max9286_v4l2_notifier_unregister(struct max9286_priv *priv)
780 {
781 	if (!priv->nsources)
782 		return;
783 
784 	v4l2_async_nf_unregister(&priv->notifier);
785 	v4l2_async_nf_cleanup(&priv->notifier);
786 }
787 
788 static int max9286_s_stream(struct v4l2_subdev *sd, int enable)
789 {
790 	struct max9286_priv *priv = sd_to_max9286(sd);
791 	struct max9286_source *source;
792 	unsigned int i;
793 	bool sync = false;
794 	int ret;
795 
796 	if (enable) {
797 		const struct v4l2_mbus_framefmt *format;
798 
799 		/*
800 		 * Get the format from the first used sink pad, as all sink
801 		 * formats must be identical.
802 		 */
803 		format = &priv->fmt[__ffs(priv->bound_sources)];
804 
805 		max9286_set_video_format(priv, format);
806 		max9286_set_fsync_period(priv);
807 
808 		/*
809 		 * The frame sync between cameras is transmitted across the
810 		 * reverse channel as GPIO. We must open all channels while
811 		 * streaming to allow this synchronisation signal to be shared.
812 		 */
813 		max9286_i2c_mux_open(priv);
814 
815 		/* Start all cameras. */
816 		for_each_source(priv, source) {
817 			ret = v4l2_subdev_call(source->sd, video, s_stream, 1);
818 			if (ret)
819 				return ret;
820 		}
821 
822 		ret = max9286_check_video_links(priv);
823 		if (ret)
824 			return ret;
825 
826 		/*
827 		 * Wait until frame synchronization is locked.
828 		 *
829 		 * Manual says frame sync locking should take ~6 VTS.
830 		 * From practical experience at least 8 are required. Give
831 		 * 12 complete frames time (~400ms at 30 fps) to achieve frame
832 		 * locking before returning error.
833 		 */
834 		for (i = 0; i < 40; i++) {
835 			if (max9286_read(priv, 0x31) & MAX9286_FSYNC_LOCKED) {
836 				sync = true;
837 				break;
838 			}
839 			usleep_range(9000, 11000);
840 		}
841 
842 		if (!sync) {
843 			dev_err(&priv->client->dev,
844 				"Failed to get frame synchronization\n");
845 			return -EXDEV; /* Invalid cross-device link */
846 		}
847 
848 		/*
849 		 * Configure the CSI-2 output to line interleaved mode (W x (N
850 		 * x H), as opposed to the (N x W) x H mode that outputs the
851 		 * images stitched side-by-side) and enable it.
852 		 */
853 		max9286_write(priv, 0x15, MAX9286_CSI_IMAGE_TYP | MAX9286_VCTYPE |
854 			      MAX9286_CSIOUTEN | MAX9286_EN_CCBSYB_CLK_STR |
855 			      MAX9286_EN_GPI_CCBSYB);
856 	} else {
857 		max9286_write(priv, 0x15, MAX9286_VCTYPE |
858 			      MAX9286_EN_CCBSYB_CLK_STR |
859 			      MAX9286_EN_GPI_CCBSYB);
860 
861 		/* Stop all cameras. */
862 		for_each_source(priv, source)
863 			v4l2_subdev_call(source->sd, video, s_stream, 0);
864 
865 		max9286_i2c_mux_close(priv);
866 	}
867 
868 	return 0;
869 }
870 
871 static int max9286_g_frame_interval(struct v4l2_subdev *sd,
872 				    struct v4l2_subdev_frame_interval *interval)
873 {
874 	struct max9286_priv *priv = sd_to_max9286(sd);
875 
876 	if (interval->pad != MAX9286_SRC_PAD)
877 		return -EINVAL;
878 
879 	interval->interval = priv->interval;
880 
881 	return 0;
882 }
883 
884 static int max9286_s_frame_interval(struct v4l2_subdev *sd,
885 				    struct v4l2_subdev_frame_interval *interval)
886 {
887 	struct max9286_priv *priv = sd_to_max9286(sd);
888 
889 	if (interval->pad != MAX9286_SRC_PAD)
890 		return -EINVAL;
891 
892 	priv->interval = interval->interval;
893 
894 	return 0;
895 }
896 
897 static int max9286_enum_mbus_code(struct v4l2_subdev *sd,
898 				  struct v4l2_subdev_state *sd_state,
899 				  struct v4l2_subdev_mbus_code_enum *code)
900 {
901 	if (code->pad || code->index > 0)
902 		return -EINVAL;
903 
904 	code->code = MEDIA_BUS_FMT_UYVY8_1X16;
905 
906 	return 0;
907 }
908 
909 static struct v4l2_mbus_framefmt *
910 max9286_get_pad_format(struct max9286_priv *priv,
911 		       struct v4l2_subdev_state *sd_state,
912 		       unsigned int pad, u32 which)
913 {
914 	switch (which) {
915 	case V4L2_SUBDEV_FORMAT_TRY:
916 		return v4l2_subdev_get_try_format(&priv->sd, sd_state, pad);
917 	case V4L2_SUBDEV_FORMAT_ACTIVE:
918 		return &priv->fmt[pad];
919 	default:
920 		return NULL;
921 	}
922 }
923 
924 static int max9286_set_fmt(struct v4l2_subdev *sd,
925 			   struct v4l2_subdev_state *sd_state,
926 			   struct v4l2_subdev_format *format)
927 {
928 	struct max9286_priv *priv = sd_to_max9286(sd);
929 	struct v4l2_mbus_framefmt *cfg_fmt;
930 	unsigned int i;
931 
932 	if (format->pad == MAX9286_SRC_PAD)
933 		return -EINVAL;
934 
935 	/* Validate the format. */
936 	for (i = 0; i < ARRAY_SIZE(max9286_formats); ++i) {
937 		if (max9286_formats[i].code == format->format.code)
938 			break;
939 	}
940 
941 	if (i == ARRAY_SIZE(max9286_formats))
942 		format->format.code = max9286_formats[0].code;
943 
944 	cfg_fmt = max9286_get_pad_format(priv, sd_state, format->pad,
945 					 format->which);
946 	if (!cfg_fmt)
947 		return -EINVAL;
948 
949 	mutex_lock(&priv->mutex);
950 	*cfg_fmt = format->format;
951 	mutex_unlock(&priv->mutex);
952 
953 	return 0;
954 }
955 
956 static int max9286_get_fmt(struct v4l2_subdev *sd,
957 			   struct v4l2_subdev_state *sd_state,
958 			   struct v4l2_subdev_format *format)
959 {
960 	struct max9286_priv *priv = sd_to_max9286(sd);
961 	struct v4l2_mbus_framefmt *cfg_fmt;
962 	unsigned int pad = format->pad;
963 
964 	/*
965 	 * Multiplexed Stream Support: Support link validation by returning the
966 	 * format of the first bound link. All links must have the same format,
967 	 * as we do not support mixing and matching of cameras connected to the
968 	 * max9286.
969 	 */
970 	if (pad == MAX9286_SRC_PAD)
971 		pad = __ffs(priv->bound_sources);
972 
973 	cfg_fmt = max9286_get_pad_format(priv, sd_state, pad, format->which);
974 	if (!cfg_fmt)
975 		return -EINVAL;
976 
977 	mutex_lock(&priv->mutex);
978 	format->format = *cfg_fmt;
979 	mutex_unlock(&priv->mutex);
980 
981 	return 0;
982 }
983 
984 static const struct v4l2_subdev_video_ops max9286_video_ops = {
985 	.s_stream	= max9286_s_stream,
986 	.g_frame_interval = max9286_g_frame_interval,
987 	.s_frame_interval = max9286_s_frame_interval,
988 };
989 
990 static const struct v4l2_subdev_pad_ops max9286_pad_ops = {
991 	.enum_mbus_code = max9286_enum_mbus_code,
992 	.get_fmt	= max9286_get_fmt,
993 	.set_fmt	= max9286_set_fmt,
994 };
995 
996 static const struct v4l2_subdev_ops max9286_subdev_ops = {
997 	.video		= &max9286_video_ops,
998 	.pad		= &max9286_pad_ops,
999 };
1000 
1001 static const struct v4l2_mbus_framefmt max9286_default_format = {
1002 	.width		= 1280,
1003 	.height		= 800,
1004 	.code		= MEDIA_BUS_FMT_UYVY8_1X16,
1005 	.colorspace	= V4L2_COLORSPACE_SRGB,
1006 	.field		= V4L2_FIELD_NONE,
1007 	.ycbcr_enc	= V4L2_YCBCR_ENC_DEFAULT,
1008 	.quantization	= V4L2_QUANTIZATION_DEFAULT,
1009 	.xfer_func	= V4L2_XFER_FUNC_DEFAULT,
1010 };
1011 
1012 static void max9286_init_format(struct v4l2_mbus_framefmt *fmt)
1013 {
1014 	*fmt = max9286_default_format;
1015 }
1016 
1017 static int max9286_open(struct v4l2_subdev *subdev, struct v4l2_subdev_fh *fh)
1018 {
1019 	struct v4l2_mbus_framefmt *format;
1020 	unsigned int i;
1021 
1022 	for (i = 0; i < MAX9286_N_SINKS; i++) {
1023 		format = v4l2_subdev_get_try_format(subdev, fh->state, i);
1024 		max9286_init_format(format);
1025 	}
1026 
1027 	return 0;
1028 }
1029 
1030 static const struct v4l2_subdev_internal_ops max9286_subdev_internal_ops = {
1031 	.open = max9286_open,
1032 };
1033 
1034 static const struct media_entity_operations max9286_media_ops = {
1035 	.link_validate = v4l2_subdev_link_validate
1036 };
1037 
1038 static int max9286_s_ctrl(struct v4l2_ctrl *ctrl)
1039 {
1040 	switch (ctrl->id) {
1041 	case V4L2_CID_PIXEL_RATE:
1042 		return 0;
1043 	default:
1044 		return -EINVAL;
1045 	}
1046 }
1047 
1048 static const struct v4l2_ctrl_ops max9286_ctrl_ops = {
1049 	.s_ctrl = max9286_s_ctrl,
1050 };
1051 
1052 static int max9286_v4l2_register(struct max9286_priv *priv)
1053 {
1054 	struct device *dev = &priv->client->dev;
1055 	int ret;
1056 	int i;
1057 
1058 	/* Register v4l2 async notifiers for connected Camera subdevices */
1059 	ret = max9286_v4l2_notifier_register(priv);
1060 	if (ret) {
1061 		dev_err(dev, "Unable to register V4L2 async notifiers\n");
1062 		return ret;
1063 	}
1064 
1065 	/* Configure V4L2 for the MAX9286 itself */
1066 
1067 	for (i = 0; i < MAX9286_N_SINKS; i++)
1068 		max9286_init_format(&priv->fmt[i]);
1069 
1070 	v4l2_i2c_subdev_init(&priv->sd, priv->client, &max9286_subdev_ops);
1071 	priv->sd.internal_ops = &max9286_subdev_internal_ops;
1072 	priv->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
1073 
1074 	v4l2_ctrl_handler_init(&priv->ctrls, 1);
1075 	priv->pixelrate_ctrl = v4l2_ctrl_new_std(&priv->ctrls,
1076 						 &max9286_ctrl_ops,
1077 						 V4L2_CID_PIXEL_RATE,
1078 						 1, INT_MAX, 1, 50000000);
1079 
1080 	priv->sd.ctrl_handler = &priv->ctrls;
1081 	ret = priv->ctrls.error;
1082 	if (ret)
1083 		goto err_async;
1084 
1085 	priv->sd.entity.function = MEDIA_ENT_F_VID_IF_BRIDGE;
1086 	priv->sd.entity.ops = &max9286_media_ops;
1087 
1088 	priv->pads[MAX9286_SRC_PAD].flags = MEDIA_PAD_FL_SOURCE;
1089 	for (i = 0; i < MAX9286_SRC_PAD; i++)
1090 		priv->pads[i].flags = MEDIA_PAD_FL_SINK;
1091 	ret = media_entity_pads_init(&priv->sd.entity, MAX9286_N_PADS,
1092 				     priv->pads);
1093 	if (ret)
1094 		goto err_async;
1095 
1096 	ret = v4l2_async_register_subdev(&priv->sd);
1097 	if (ret < 0) {
1098 		dev_err(dev, "Unable to register subdevice\n");
1099 		goto err_async;
1100 	}
1101 
1102 	return 0;
1103 
1104 err_async:
1105 	v4l2_ctrl_handler_free(&priv->ctrls);
1106 	max9286_v4l2_notifier_unregister(priv);
1107 
1108 	return ret;
1109 }
1110 
1111 static void max9286_v4l2_unregister(struct max9286_priv *priv)
1112 {
1113 	fwnode_handle_put(priv->sd.fwnode);
1114 	v4l2_ctrl_handler_free(&priv->ctrls);
1115 	v4l2_async_unregister_subdev(&priv->sd);
1116 	max9286_v4l2_notifier_unregister(priv);
1117 }
1118 
1119 /* -----------------------------------------------------------------------------
1120  * Probe/Remove
1121  */
1122 
1123 static int max9286_setup(struct max9286_priv *priv)
1124 {
1125 	/*
1126 	 * Link ordering values for all enabled links combinations. Orders must
1127 	 * be assigned sequentially from 0 to the number of enabled links
1128 	 * without leaving any hole for disabled links. We thus assign orders to
1129 	 * enabled links first, and use the remaining order values for disabled
1130 	 * links are all links must have a different order value;
1131 	 */
1132 	static const u8 link_order[] = {
1133 		(3 << 6) | (2 << 4) | (1 << 2) | (0 << 0), /* xxxx */
1134 		(3 << 6) | (2 << 4) | (1 << 2) | (0 << 0), /* xxx0 */
1135 		(3 << 6) | (2 << 4) | (0 << 2) | (1 << 0), /* xx0x */
1136 		(3 << 6) | (2 << 4) | (1 << 2) | (0 << 0), /* xx10 */
1137 		(3 << 6) | (0 << 4) | (2 << 2) | (1 << 0), /* x0xx */
1138 		(3 << 6) | (1 << 4) | (2 << 2) | (0 << 0), /* x1x0 */
1139 		(3 << 6) | (1 << 4) | (0 << 2) | (2 << 0), /* x10x */
1140 		(3 << 6) | (1 << 4) | (1 << 2) | (0 << 0), /* x210 */
1141 		(0 << 6) | (3 << 4) | (2 << 2) | (1 << 0), /* 0xxx */
1142 		(1 << 6) | (3 << 4) | (2 << 2) | (0 << 0), /* 1xx0 */
1143 		(1 << 6) | (3 << 4) | (0 << 2) | (2 << 0), /* 1x0x */
1144 		(2 << 6) | (3 << 4) | (1 << 2) | (0 << 0), /* 2x10 */
1145 		(1 << 6) | (0 << 4) | (3 << 2) | (2 << 0), /* 10xx */
1146 		(2 << 6) | (1 << 4) | (3 << 2) | (0 << 0), /* 21x0 */
1147 		(2 << 6) | (1 << 4) | (0 << 2) | (3 << 0), /* 210x */
1148 		(3 << 6) | (2 << 4) | (1 << 2) | (0 << 0), /* 3210 */
1149 	};
1150 	int cfg;
1151 
1152 	/*
1153 	 * Set the I2C bus speed.
1154 	 *
1155 	 * Enable I2C Local Acknowledge during the probe sequences of the camera
1156 	 * only. This should be disabled after the mux is initialised.
1157 	 */
1158 	max9286_configure_i2c(priv, true);
1159 	max9286_reverse_channel_setup(priv, priv->init_rev_chan_mv);
1160 
1161 	/*
1162 	 * Enable GMSL links, mask unused ones and autodetect link
1163 	 * used as CSI clock source.
1164 	 */
1165 	max9286_write(priv, 0x00, MAX9286_MSTLINKSEL_AUTO | priv->route_mask);
1166 	max9286_write(priv, 0x0b, link_order[priv->route_mask]);
1167 	max9286_write(priv, 0x69, (0xf & ~priv->route_mask));
1168 
1169 	max9286_set_video_format(priv, &max9286_default_format);
1170 	max9286_set_fsync_period(priv);
1171 
1172 	cfg = max9286_read(priv, 0x1c);
1173 	if (cfg < 0)
1174 		return cfg;
1175 
1176 	dev_dbg(&priv->client->dev, "power-up config: %s immunity, %u-bit bus\n",
1177 		cfg & MAX9286_HIGHIMM(0) ? "high" : "legacy",
1178 		cfg & MAX9286_BWS ? 32 : cfg & MAX9286_HIBW ? 27 : 24);
1179 
1180 	if (priv->bus_width) {
1181 		cfg &= ~(MAX9286_HIBW | MAX9286_BWS);
1182 
1183 		if (priv->bus_width == 27)
1184 			cfg |= MAX9286_HIBW;
1185 		else if (priv->bus_width == 32)
1186 			cfg |= MAX9286_BWS;
1187 
1188 		max9286_write(priv, 0x1c, cfg);
1189 	}
1190 
1191 	/*
1192 	 * The overlap window seems to provide additional validation by tracking
1193 	 * the delay between vsync and frame sync, generating an error if the
1194 	 * delay is bigger than the programmed window, though it's not yet clear
1195 	 * what value should be set.
1196 	 *
1197 	 * As it's an optional value and can be disabled, we do so by setting
1198 	 * a 0 overlap value.
1199 	 */
1200 	max9286_write(priv, 0x63, 0);
1201 	max9286_write(priv, 0x64, 0);
1202 
1203 	/*
1204 	 * Wait for 2ms to allow the link to resynchronize after the
1205 	 * configuration change.
1206 	 */
1207 	usleep_range(2000, 5000);
1208 
1209 	return 0;
1210 }
1211 
1212 static int max9286_gpio_set(struct max9286_priv *priv, unsigned int offset,
1213 			    int value)
1214 {
1215 	if (value)
1216 		priv->gpio_state |= BIT(offset);
1217 	else
1218 		priv->gpio_state &= ~BIT(offset);
1219 
1220 	return max9286_write(priv, 0x0f,
1221 			     MAX9286_0X0F_RESERVED | priv->gpio_state);
1222 }
1223 
1224 static void max9286_gpiochip_set(struct gpio_chip *chip,
1225 				 unsigned int offset, int value)
1226 {
1227 	struct max9286_priv *priv = gpiochip_get_data(chip);
1228 
1229 	max9286_gpio_set(priv, offset, value);
1230 }
1231 
1232 static int max9286_gpiochip_get(struct gpio_chip *chip, unsigned int offset)
1233 {
1234 	struct max9286_priv *priv = gpiochip_get_data(chip);
1235 
1236 	return priv->gpio_state & BIT(offset);
1237 }
1238 
1239 static int max9286_register_gpio(struct max9286_priv *priv)
1240 {
1241 	struct device *dev = &priv->client->dev;
1242 	struct gpio_chip *gpio = &priv->gpio;
1243 	int ret;
1244 
1245 	/* Configure the GPIO */
1246 	gpio->label = dev_name(dev);
1247 	gpio->parent = dev;
1248 	gpio->owner = THIS_MODULE;
1249 	gpio->ngpio = 2;
1250 	gpio->base = -1;
1251 	gpio->set = max9286_gpiochip_set;
1252 	gpio->get = max9286_gpiochip_get;
1253 	gpio->can_sleep = true;
1254 
1255 	ret = devm_gpiochip_add_data(dev, gpio, priv);
1256 	if (ret)
1257 		dev_err(dev, "Unable to create gpio_chip\n");
1258 
1259 	return ret;
1260 }
1261 
1262 static int max9286_parse_gpios(struct max9286_priv *priv)
1263 {
1264 	struct device *dev = &priv->client->dev;
1265 	int ret;
1266 
1267 	/*
1268 	 * Parse the "gpio-poc" vendor property. If the property is not
1269 	 * specified the camera power is controlled by a regulator.
1270 	 */
1271 	ret = of_property_read_u32_array(dev->of_node, "maxim,gpio-poc",
1272 					 priv->gpio_poc, 2);
1273 	if (ret == -EINVAL) {
1274 		/*
1275 		 * If gpio lines are not used for the camera power, register
1276 		 * a gpio controller for consumers.
1277 		 */
1278 		return max9286_register_gpio(priv);
1279 	}
1280 
1281 	/* If the property is specified make sure it is well formed. */
1282 	if (ret || priv->gpio_poc[0] > 1 ||
1283 	    (priv->gpio_poc[1] != GPIO_ACTIVE_HIGH &&
1284 	     priv->gpio_poc[1] != GPIO_ACTIVE_LOW)) {
1285 		dev_err(dev, "Invalid 'gpio-poc' property\n");
1286 		return -EINVAL;
1287 	}
1288 
1289 	priv->use_gpio_poc = true;
1290 	return 0;
1291 }
1292 
1293 static int max9286_poc_power_on(struct max9286_priv *priv)
1294 {
1295 	struct max9286_source *source;
1296 	unsigned int enabled = 0;
1297 	int ret;
1298 
1299 	/* Enable the global regulator if available. */
1300 	if (priv->regulator)
1301 		return regulator_enable(priv->regulator);
1302 
1303 	if (priv->use_gpio_poc)
1304 		return max9286_gpio_set(priv, priv->gpio_poc[0],
1305 					!priv->gpio_poc[1]);
1306 
1307 	/* Otherwise use the per-port regulators. */
1308 	for_each_source(priv, source) {
1309 		ret = regulator_enable(source->regulator);
1310 		if (ret < 0)
1311 			goto error;
1312 
1313 		enabled |= BIT(to_index(priv, source));
1314 	}
1315 
1316 	return 0;
1317 
1318 error:
1319 	for_each_source(priv, source) {
1320 		if (enabled & BIT(to_index(priv, source)))
1321 			regulator_disable(source->regulator);
1322 	}
1323 
1324 	return ret;
1325 }
1326 
1327 static int max9286_poc_power_off(struct max9286_priv *priv)
1328 {
1329 	struct max9286_source *source;
1330 	int ret = 0;
1331 
1332 	if (priv->regulator)
1333 		return regulator_disable(priv->regulator);
1334 
1335 	if (priv->use_gpio_poc)
1336 		return max9286_gpio_set(priv, priv->gpio_poc[0],
1337 					priv->gpio_poc[1]);
1338 
1339 	for_each_source(priv, source) {
1340 		int err;
1341 
1342 		err = regulator_disable(source->regulator);
1343 		if (!ret)
1344 			ret = err;
1345 	}
1346 
1347 	return ret;
1348 }
1349 
1350 static int max9286_poc_enable(struct max9286_priv *priv, bool enable)
1351 {
1352 	int ret;
1353 
1354 	if (enable)
1355 		ret = max9286_poc_power_on(priv);
1356 	else
1357 		ret = max9286_poc_power_off(priv);
1358 
1359 	if (ret < 0)
1360 		dev_err(&priv->client->dev, "Unable to turn power %s\n",
1361 			enable ? "on" : "off");
1362 
1363 	return ret;
1364 }
1365 
1366 static int max9286_init(struct max9286_priv *priv)
1367 {
1368 	struct i2c_client *client = priv->client;
1369 	int ret;
1370 
1371 	ret = max9286_poc_enable(priv, true);
1372 	if (ret)
1373 		return ret;
1374 
1375 	ret = max9286_setup(priv);
1376 	if (ret) {
1377 		dev_err(&client->dev, "Unable to setup max9286\n");
1378 		goto err_poc_disable;
1379 	}
1380 
1381 	/*
1382 	 * Register all V4L2 interactions for the MAX9286 and notifiers for
1383 	 * any subdevices connected.
1384 	 */
1385 	ret = max9286_v4l2_register(priv);
1386 	if (ret) {
1387 		dev_err(&client->dev, "Failed to register with V4L2\n");
1388 		goto err_poc_disable;
1389 	}
1390 
1391 	ret = max9286_i2c_mux_init(priv);
1392 	if (ret) {
1393 		dev_err(&client->dev, "Unable to initialize I2C multiplexer\n");
1394 		goto err_v4l2_register;
1395 	}
1396 
1397 	/* Leave the mux channels disabled until they are selected. */
1398 	max9286_i2c_mux_close(priv);
1399 
1400 	return 0;
1401 
1402 err_v4l2_register:
1403 	max9286_v4l2_unregister(priv);
1404 err_poc_disable:
1405 	max9286_poc_enable(priv, false);
1406 
1407 	return ret;
1408 }
1409 
1410 static void max9286_cleanup_dt(struct max9286_priv *priv)
1411 {
1412 	struct max9286_source *source;
1413 
1414 	for_each_source(priv, source) {
1415 		fwnode_handle_put(source->fwnode);
1416 		source->fwnode = NULL;
1417 	}
1418 }
1419 
1420 static int max9286_parse_dt(struct max9286_priv *priv)
1421 {
1422 	struct device *dev = &priv->client->dev;
1423 	struct device_node *i2c_mux;
1424 	struct device_node *node = NULL;
1425 	unsigned int i2c_mux_mask = 0;
1426 	u32 reverse_channel_microvolt;
1427 	u32 i2c_clk_freq = 105000;
1428 	unsigned int i;
1429 
1430 	/* Balance the of_node_put() performed by of_find_node_by_name(). */
1431 	of_node_get(dev->of_node);
1432 	i2c_mux = of_find_node_by_name(dev->of_node, "i2c-mux");
1433 	if (!i2c_mux) {
1434 		dev_err(dev, "Failed to find i2c-mux node\n");
1435 		return -EINVAL;
1436 	}
1437 
1438 	/* Identify which i2c-mux channels are enabled */
1439 	for_each_child_of_node(i2c_mux, node) {
1440 		u32 id = 0;
1441 
1442 		of_property_read_u32(node, "reg", &id);
1443 		if (id >= MAX9286_NUM_GMSL)
1444 			continue;
1445 
1446 		if (!of_device_is_available(node)) {
1447 			dev_dbg(dev, "Skipping disabled I2C bus port %u\n", id);
1448 			continue;
1449 		}
1450 
1451 		i2c_mux_mask |= BIT(id);
1452 	}
1453 	of_node_put(node);
1454 	of_node_put(i2c_mux);
1455 
1456 	/* Parse the endpoints */
1457 	for_each_endpoint_of_node(dev->of_node, node) {
1458 		struct max9286_source *source;
1459 		struct of_endpoint ep;
1460 
1461 		of_graph_parse_endpoint(node, &ep);
1462 		dev_dbg(dev, "Endpoint %pOF on port %d",
1463 			ep.local_node, ep.port);
1464 
1465 		if (ep.port > MAX9286_NUM_GMSL) {
1466 			dev_err(dev, "Invalid endpoint %s on port %d",
1467 				of_node_full_name(ep.local_node), ep.port);
1468 			continue;
1469 		}
1470 
1471 		/* For the source endpoint just parse the bus configuration. */
1472 		if (ep.port == MAX9286_SRC_PAD) {
1473 			struct v4l2_fwnode_endpoint vep = {
1474 				.bus_type = V4L2_MBUS_CSI2_DPHY
1475 			};
1476 			int ret;
1477 
1478 			ret = v4l2_fwnode_endpoint_parse(
1479 					of_fwnode_handle(node), &vep);
1480 			if (ret) {
1481 				of_node_put(node);
1482 				return ret;
1483 			}
1484 
1485 			priv->csi2_data_lanes =
1486 				vep.bus.mipi_csi2.num_data_lanes;
1487 
1488 			continue;
1489 		}
1490 
1491 		/* Skip if the corresponding GMSL link is unavailable. */
1492 		if (!(i2c_mux_mask & BIT(ep.port)))
1493 			continue;
1494 
1495 		if (priv->sources[ep.port].fwnode) {
1496 			dev_err(dev,
1497 				"Multiple port endpoints are not supported: %d",
1498 				ep.port);
1499 
1500 			continue;
1501 		}
1502 
1503 		source = &priv->sources[ep.port];
1504 		source->fwnode = fwnode_graph_get_remote_endpoint(
1505 						of_fwnode_handle(node));
1506 		if (!source->fwnode) {
1507 			dev_err(dev,
1508 				"Endpoint %pOF has no remote endpoint connection\n",
1509 				ep.local_node);
1510 
1511 			continue;
1512 		}
1513 
1514 		priv->source_mask |= BIT(ep.port);
1515 		priv->nsources++;
1516 	}
1517 	of_node_put(node);
1518 
1519 	of_property_read_u32(dev->of_node, "maxim,bus-width", &priv->bus_width);
1520 	switch (priv->bus_width) {
1521 	case 0:
1522 		/*
1523 		 * The property isn't specified in the device tree, the driver
1524 		 * will keep the default value selected by the BWS pin.
1525 		 */
1526 	case 24:
1527 	case 27:
1528 	case 32:
1529 		break;
1530 	default:
1531 		dev_err(dev, "Invalid %s value %u\n", "maxim,bus-width",
1532 			priv->bus_width);
1533 		return -EINVAL;
1534 	}
1535 
1536 	of_property_read_u32(dev->of_node, "maxim,i2c-remote-bus-hz",
1537 			     &i2c_clk_freq);
1538 	for (i = 0; i < ARRAY_SIZE(max9286_i2c_speeds); ++i) {
1539 		const struct max9286_i2c_speed *speed = &max9286_i2c_speeds[i];
1540 
1541 		if (speed->rate == i2c_clk_freq) {
1542 			priv->i2c_mstbt = speed->mstbt;
1543 			break;
1544 		}
1545 	}
1546 
1547 	if (i == ARRAY_SIZE(max9286_i2c_speeds)) {
1548 		dev_err(dev, "Invalid %s value %u\n", "maxim,i2c-remote-bus-hz",
1549 			i2c_clk_freq);
1550 		return -EINVAL;
1551 	}
1552 
1553 	/*
1554 	 * Parse the initial value of the reverse channel amplitude from
1555 	 * the firmware interface and convert it to millivolts.
1556 	 *
1557 	 * Default it to 170mV for backward compatibility with DTBs that do not
1558 	 * provide the property.
1559 	 */
1560 	if (of_property_read_u32(dev->of_node,
1561 				 "maxim,reverse-channel-microvolt",
1562 				 &reverse_channel_microvolt))
1563 		priv->init_rev_chan_mv = 170;
1564 	else
1565 		priv->init_rev_chan_mv = reverse_channel_microvolt / 1000U;
1566 
1567 	priv->route_mask = priv->source_mask;
1568 
1569 	return 0;
1570 }
1571 
1572 static int max9286_get_poc_supplies(struct max9286_priv *priv)
1573 {
1574 	struct device *dev = &priv->client->dev;
1575 	struct max9286_source *source;
1576 	int ret;
1577 
1578 	/* Start by getting the global regulator. */
1579 	priv->regulator = devm_regulator_get_optional(dev, "poc");
1580 	if (!IS_ERR(priv->regulator))
1581 		return 0;
1582 
1583 	if (PTR_ERR(priv->regulator) != -ENODEV)
1584 		return dev_err_probe(dev, PTR_ERR(priv->regulator),
1585 				     "Unable to get PoC regulator\n");
1586 
1587 	/* If there's no global regulator, get per-port regulators. */
1588 	dev_dbg(dev,
1589 		"No global PoC regulator, looking for per-port regulators\n");
1590 	priv->regulator = NULL;
1591 
1592 	for_each_source(priv, source) {
1593 		unsigned int index = to_index(priv, source);
1594 		char name[10];
1595 
1596 		snprintf(name, sizeof(name), "port%u-poc", index);
1597 		source->regulator = devm_regulator_get(dev, name);
1598 		if (IS_ERR(source->regulator)) {
1599 			ret = PTR_ERR(source->regulator);
1600 			dev_err_probe(dev, ret,
1601 				      "Unable to get port %u PoC regulator\n",
1602 				      index);
1603 			return ret;
1604 		}
1605 	}
1606 
1607 	return 0;
1608 }
1609 
1610 static int max9286_probe(struct i2c_client *client)
1611 {
1612 	struct max9286_priv *priv;
1613 	int ret;
1614 
1615 	priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
1616 	if (!priv)
1617 		return -ENOMEM;
1618 
1619 	mutex_init(&priv->mutex);
1620 
1621 	priv->client = client;
1622 
1623 	/* GPIO values default to high */
1624 	priv->gpio_state = BIT(0) | BIT(1);
1625 
1626 	ret = max9286_parse_dt(priv);
1627 	if (ret)
1628 		goto err_cleanup_dt;
1629 
1630 	priv->gpiod_pwdn = devm_gpiod_get_optional(&client->dev, "enable",
1631 						   GPIOD_OUT_HIGH);
1632 	if (IS_ERR(priv->gpiod_pwdn)) {
1633 		ret = PTR_ERR(priv->gpiod_pwdn);
1634 		goto err_cleanup_dt;
1635 	}
1636 
1637 	gpiod_set_consumer_name(priv->gpiod_pwdn, "max9286-pwdn");
1638 	gpiod_set_value_cansleep(priv->gpiod_pwdn, 1);
1639 
1640 	/* Wait at least 4ms before the I2C lines latch to the address */
1641 	if (priv->gpiod_pwdn)
1642 		usleep_range(4000, 5000);
1643 
1644 	/*
1645 	 * The MAX9286 starts by default with all ports enabled, we disable all
1646 	 * ports early to ensure that all channels are disabled if we error out
1647 	 * and keep the bus consistent.
1648 	 */
1649 	max9286_i2c_mux_close(priv);
1650 
1651 	/*
1652 	 * The MAX9286 initialises with auto-acknowledge enabled by default.
1653 	 * This can be invasive to other transactions on the same bus, so
1654 	 * disable it early. It will be enabled only as and when needed.
1655 	 */
1656 	max9286_configure_i2c(priv, false);
1657 
1658 	ret = max9286_parse_gpios(priv);
1659 	if (ret)
1660 		goto err_powerdown;
1661 
1662 	if (!priv->use_gpio_poc) {
1663 		ret = max9286_get_poc_supplies(priv);
1664 		if (ret)
1665 			goto err_cleanup_dt;
1666 	}
1667 
1668 	ret = max9286_init(priv);
1669 	if (ret < 0)
1670 		goto err_cleanup_dt;
1671 
1672 	return 0;
1673 
1674 err_powerdown:
1675 	gpiod_set_value_cansleep(priv->gpiod_pwdn, 0);
1676 err_cleanup_dt:
1677 	max9286_cleanup_dt(priv);
1678 
1679 	return ret;
1680 }
1681 
1682 static void max9286_remove(struct i2c_client *client)
1683 {
1684 	struct max9286_priv *priv = sd_to_max9286(i2c_get_clientdata(client));
1685 
1686 	i2c_mux_del_adapters(priv->mux);
1687 
1688 	max9286_v4l2_unregister(priv);
1689 
1690 	max9286_poc_enable(priv, false);
1691 
1692 	gpiod_set_value_cansleep(priv->gpiod_pwdn, 0);
1693 
1694 	max9286_cleanup_dt(priv);
1695 }
1696 
1697 static const struct of_device_id max9286_dt_ids[] = {
1698 	{ .compatible = "maxim,max9286" },
1699 	{},
1700 };
1701 MODULE_DEVICE_TABLE(of, max9286_dt_ids);
1702 
1703 static struct i2c_driver max9286_i2c_driver = {
1704 	.driver	= {
1705 		.name		= "max9286",
1706 		.of_match_table	= max9286_dt_ids,
1707 	},
1708 	.probe		= max9286_probe,
1709 	.remove		= max9286_remove,
1710 };
1711 
1712 module_i2c_driver(max9286_i2c_driver);
1713 
1714 MODULE_DESCRIPTION("Maxim MAX9286 GMSL Deserializer Driver");
1715 MODULE_AUTHOR("Jacopo Mondi, Kieran Bingham, Laurent Pinchart, Niklas Söderlund, Vladimir Barinov");
1716 MODULE_LICENSE("GPL");
1717