xref: /linux/drivers/media/i2c/max9286.c (revision 81c29435073355b8194986a2193d3e7b9d449225)
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_subdev base;
165 	struct max9286_source *source;
166 };
167 
168 static inline struct max9286_asd *to_max9286_asd(struct v4l2_async_subdev *asd)
169 {
170 	return container_of(asd, struct max9286_asd, base);
171 }
172 
173 struct max9286_priv {
174 	struct i2c_client *client;
175 	struct gpio_desc *gpiod_pwdn;
176 	struct v4l2_subdev sd;
177 	struct media_pad pads[MAX9286_N_PADS];
178 	struct regulator *regulator;
179 
180 	struct gpio_chip gpio;
181 	u8 gpio_state;
182 
183 	struct i2c_mux_core *mux;
184 	unsigned int mux_channel;
185 	bool mux_open;
186 
187 	/* The initial reverse control channel amplitude. */
188 	u32 init_rev_chan_mv;
189 	u32 rev_chan_mv;
190 	u8 i2c_mstbt;
191 	u32 bus_width;
192 
193 	bool use_gpio_poc;
194 	u32 gpio_poc[2];
195 
196 	struct v4l2_ctrl_handler ctrls;
197 	struct v4l2_ctrl *pixelrate_ctrl;
198 	unsigned int pixelrate;
199 
200 	struct v4l2_mbus_framefmt fmt[MAX9286_N_SINKS];
201 	struct v4l2_fract interval;
202 
203 	/* Protects controls and fmt structures */
204 	struct mutex mutex;
205 
206 	unsigned int nsources;
207 	unsigned int source_mask;
208 	unsigned int route_mask;
209 	unsigned int bound_sources;
210 	unsigned int csi2_data_lanes;
211 	struct max9286_source sources[MAX9286_NUM_GMSL];
212 	struct v4l2_async_notifier notifier;
213 };
214 
215 static struct max9286_source *next_source(struct max9286_priv *priv,
216 					  struct max9286_source *source)
217 {
218 	if (!source)
219 		source = &priv->sources[0];
220 	else
221 		source++;
222 
223 	for (; source < &priv->sources[MAX9286_NUM_GMSL]; source++) {
224 		if (source->fwnode)
225 			return source;
226 	}
227 
228 	return NULL;
229 }
230 
231 #define for_each_source(priv, source) \
232 	for ((source) = NULL; ((source) = next_source((priv), (source))); )
233 
234 #define to_index(priv, source) ((source) - &(priv)->sources[0])
235 
236 static inline struct max9286_priv *sd_to_max9286(struct v4l2_subdev *sd)
237 {
238 	return container_of(sd, struct max9286_priv, sd);
239 }
240 
241 static const struct max9286_format_info max9286_formats[] = {
242 	{
243 		.code = MEDIA_BUS_FMT_UYVY8_1X16,
244 		.datatype = MAX9286_DATATYPE_YUV422_8BIT,
245 	}, {
246 		.code = MEDIA_BUS_FMT_VYUY8_1X16,
247 		.datatype = MAX9286_DATATYPE_YUV422_8BIT,
248 	}, {
249 		.code = MEDIA_BUS_FMT_YUYV8_1X16,
250 		.datatype = MAX9286_DATATYPE_YUV422_8BIT,
251 	}, {
252 		.code = MEDIA_BUS_FMT_YVYU8_1X16,
253 		.datatype = MAX9286_DATATYPE_YUV422_8BIT,
254 	}, {
255 		.code = MEDIA_BUS_FMT_SBGGR12_1X12,
256 		.datatype = MAX9286_DATATYPE_RAW12,
257 	}, {
258 		.code = MEDIA_BUS_FMT_SGBRG12_1X12,
259 		.datatype = MAX9286_DATATYPE_RAW12,
260 	}, {
261 		.code = MEDIA_BUS_FMT_SGRBG12_1X12,
262 		.datatype = MAX9286_DATATYPE_RAW12,
263 	}, {
264 		.code = MEDIA_BUS_FMT_SRGGB12_1X12,
265 		.datatype = MAX9286_DATATYPE_RAW12,
266 	},
267 };
268 
269 static const struct max9286_i2c_speed max9286_i2c_speeds[] = {
270 	{ .rate =   8470, .mstbt = MAX9286_I2CMSTBT_8KBPS },
271 	{ .rate =  28300, .mstbt = MAX9286_I2CMSTBT_28KBPS },
272 	{ .rate =  84700, .mstbt = MAX9286_I2CMSTBT_84KBPS },
273 	{ .rate = 105000, .mstbt = MAX9286_I2CMSTBT_105KBPS },
274 	{ .rate = 173000, .mstbt = MAX9286_I2CMSTBT_173KBPS },
275 	{ .rate = 339000, .mstbt = MAX9286_I2CMSTBT_339KBPS },
276 	{ .rate = 533000, .mstbt = MAX9286_I2CMSTBT_533KBPS },
277 	{ .rate = 837000, .mstbt = MAX9286_I2CMSTBT_837KBPS },
278 };
279 
280 /* -----------------------------------------------------------------------------
281  * I2C IO
282  */
283 
284 static int max9286_read(struct max9286_priv *priv, u8 reg)
285 {
286 	int ret;
287 
288 	ret = i2c_smbus_read_byte_data(priv->client, reg);
289 	if (ret < 0)
290 		dev_err(&priv->client->dev,
291 			"%s: register 0x%02x read failed (%d)\n",
292 			__func__, reg, ret);
293 
294 	return ret;
295 }
296 
297 static int max9286_write(struct max9286_priv *priv, u8 reg, u8 val)
298 {
299 	int ret;
300 
301 	ret = i2c_smbus_write_byte_data(priv->client, reg, val);
302 	if (ret < 0)
303 		dev_err(&priv->client->dev,
304 			"%s: register 0x%02x write failed (%d)\n",
305 			__func__, reg, ret);
306 
307 	return ret;
308 }
309 
310 /* -----------------------------------------------------------------------------
311  * I2C Multiplexer
312  */
313 
314 static void max9286_i2c_mux_configure(struct max9286_priv *priv, u8 conf)
315 {
316 	max9286_write(priv, 0x0a, conf);
317 
318 	/*
319 	 * We must sleep after any change to the forward or reverse channel
320 	 * configuration.
321 	 */
322 	usleep_range(3000, 5000);
323 }
324 
325 static void max9286_i2c_mux_open(struct max9286_priv *priv)
326 {
327 	/* Open all channels on the MAX9286 */
328 	max9286_i2c_mux_configure(priv, 0xff);
329 
330 	priv->mux_open = true;
331 }
332 
333 static void max9286_i2c_mux_close(struct max9286_priv *priv)
334 {
335 	/*
336 	 * Ensure that both the forward and reverse channel are disabled on the
337 	 * mux, and that the channel ID is invalidated to ensure we reconfigure
338 	 * on the next max9286_i2c_mux_select() call.
339 	 */
340 	max9286_i2c_mux_configure(priv, 0x00);
341 
342 	priv->mux_open = false;
343 	priv->mux_channel = -1;
344 }
345 
346 static int max9286_i2c_mux_select(struct i2c_mux_core *muxc, u32 chan)
347 {
348 	struct max9286_priv *priv = i2c_mux_priv(muxc);
349 
350 	/* Channel select is disabled when configured in the opened state. */
351 	if (priv->mux_open)
352 		return 0;
353 
354 	if (priv->mux_channel == chan)
355 		return 0;
356 
357 	priv->mux_channel = chan;
358 
359 	max9286_i2c_mux_configure(priv, MAX9286_FWDCCEN(chan) |
360 					MAX9286_REVCCEN(chan));
361 
362 	return 0;
363 }
364 
365 static int max9286_i2c_mux_init(struct max9286_priv *priv)
366 {
367 	struct max9286_source *source;
368 	int ret;
369 
370 	if (!i2c_check_functionality(priv->client->adapter,
371 				     I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
372 		return -ENODEV;
373 
374 	priv->mux = i2c_mux_alloc(priv->client->adapter, &priv->client->dev,
375 				  priv->nsources, 0, I2C_MUX_LOCKED,
376 				  max9286_i2c_mux_select, NULL);
377 	if (!priv->mux)
378 		return -ENOMEM;
379 
380 	priv->mux->priv = priv;
381 
382 	for_each_source(priv, source) {
383 		unsigned int index = to_index(priv, source);
384 
385 		ret = i2c_mux_add_adapter(priv->mux, 0, index, 0);
386 		if (ret < 0)
387 			goto error;
388 	}
389 
390 	return 0;
391 
392 error:
393 	i2c_mux_del_adapters(priv->mux);
394 	return ret;
395 }
396 
397 static void max9286_configure_i2c(struct max9286_priv *priv, bool localack)
398 {
399 	u8 config = MAX9286_I2CSLVSH_469NS_234NS | MAX9286_I2CSLVTO_1024US |
400 		    priv->i2c_mstbt;
401 
402 	if (localack)
403 		config |= MAX9286_I2CLOCACK;
404 
405 	max9286_write(priv, 0x34, config);
406 	usleep_range(3000, 5000);
407 }
408 
409 static void max9286_reverse_channel_setup(struct max9286_priv *priv,
410 					  unsigned int chan_amplitude)
411 {
412 	u8 chan_config;
413 
414 	if (priv->rev_chan_mv == chan_amplitude)
415 		return;
416 
417 	priv->rev_chan_mv = chan_amplitude;
418 
419 	/* Reverse channel transmission time: default to 1. */
420 	chan_config = MAX9286_REV_TRF(1);
421 
422 	/*
423 	 * Reverse channel setup.
424 	 *
425 	 * - Enable custom reverse channel configuration (through register 0x3f)
426 	 *   and set the first pulse length to 35 clock cycles.
427 	 * - Adjust reverse channel amplitude: values > 130 are programmed
428 	 *   using the additional +100mV REV_AMP_X boost flag
429 	 */
430 	max9286_write(priv, 0x3f, MAX9286_EN_REV_CFG | MAX9286_REV_FLEN(35));
431 
432 	if (chan_amplitude > 100) {
433 		/* It is not possible to express values (100 < x < 130) */
434 		chan_amplitude = max(30U, chan_amplitude - 100);
435 		chan_config |= MAX9286_REV_AMP_X;
436 	}
437 	max9286_write(priv, 0x3b, chan_config | MAX9286_REV_AMP(chan_amplitude));
438 	usleep_range(2000, 2500);
439 }
440 
441 /*
442  * max9286_check_video_links() - Make sure video links are detected and locked
443  *
444  * Performs safety checks on video link status. Make sure they are detected
445  * and all enabled links are locked.
446  *
447  * Returns 0 for success, -EIO for errors.
448  */
449 static int max9286_check_video_links(struct max9286_priv *priv)
450 {
451 	unsigned int i;
452 	int ret;
453 
454 	/*
455 	 * Make sure valid video links are detected.
456 	 * The delay is not characterized in de-serializer manual, wait up
457 	 * to 5 ms.
458 	 */
459 	for (i = 0; i < 10; i++) {
460 		ret = max9286_read(priv, 0x49);
461 		if (ret < 0)
462 			return -EIO;
463 
464 		if ((ret & MAX9286_VIDEO_DETECT_MASK) == priv->source_mask)
465 			break;
466 
467 		usleep_range(350, 500);
468 	}
469 
470 	if (i == 10) {
471 		dev_err(&priv->client->dev,
472 			"Unable to detect video links: 0x%02x\n", ret);
473 		return -EIO;
474 	}
475 
476 	/* Make sure all enabled links are locked (4ms max). */
477 	for (i = 0; i < 10; i++) {
478 		ret = max9286_read(priv, 0x27);
479 		if (ret < 0)
480 			return -EIO;
481 
482 		if (ret & MAX9286_LOCKED)
483 			break;
484 
485 		usleep_range(350, 450);
486 	}
487 
488 	if (i == 10) {
489 		dev_err(&priv->client->dev, "Not all enabled links locked\n");
490 		return -EIO;
491 	}
492 
493 	return 0;
494 }
495 
496 /*
497  * max9286_check_config_link() - Detect and wait for configuration links
498  *
499  * Determine if the configuration channel is up and settled for a link.
500  *
501  * Returns 0 for success, -EIO for errors.
502  */
503 static int max9286_check_config_link(struct max9286_priv *priv,
504 				     unsigned int source_mask)
505 {
506 	unsigned int conflink_mask = (source_mask & 0x0f) << 4;
507 	unsigned int i;
508 	int ret;
509 
510 	/*
511 	 * Make sure requested configuration links are detected.
512 	 * The delay is not characterized in the chip manual: wait up
513 	 * to 5 milliseconds.
514 	 */
515 	for (i = 0; i < 10; i++) {
516 		ret = max9286_read(priv, 0x49);
517 		if (ret < 0)
518 			return -EIO;
519 
520 		ret &= 0xf0;
521 		if (ret == conflink_mask)
522 			break;
523 
524 		usleep_range(350, 500);
525 	}
526 
527 	if (ret != conflink_mask) {
528 		dev_err(&priv->client->dev,
529 			"Unable to detect configuration links: 0x%02x expected 0x%02x\n",
530 			ret, conflink_mask);
531 		return -EIO;
532 	}
533 
534 	dev_info(&priv->client->dev,
535 		 "Successfully detected configuration links after %u loops: 0x%02x\n",
536 		 i, conflink_mask);
537 
538 	return 0;
539 }
540 
541 static void max9286_set_video_format(struct max9286_priv *priv,
542 				     const struct v4l2_mbus_framefmt *format)
543 {
544 	const struct max9286_format_info *info = NULL;
545 	unsigned int i;
546 
547 	for (i = 0; i < ARRAY_SIZE(max9286_formats); ++i) {
548 		if (max9286_formats[i].code == format->code) {
549 			info = &max9286_formats[i];
550 			break;
551 		}
552 	}
553 
554 	if (WARN_ON(!info))
555 		return;
556 
557 	/*
558 	 * Video format setup: disable CSI output, set VC according to Link
559 	 * number, enable I2C clock stretching when CCBSY is low, enable CCBSY
560 	 * in external GPI-to-GPO mode.
561 	 */
562 	max9286_write(priv, 0x15, MAX9286_VCTYPE | MAX9286_EN_CCBSYB_CLK_STR |
563 		      MAX9286_EN_GPI_CCBSYB);
564 
565 	/* Enable CSI-2 Lane D0-D3 only, DBL mode. */
566 	max9286_write(priv, 0x12, MAX9286_CSIDBL | MAX9286_DBL |
567 		      MAX9286_CSILANECNT(priv->csi2_data_lanes) |
568 		      info->datatype);
569 
570 	/*
571 	 * Enable HS/VS encoding, use HS as line valid source, use D14/15 for
572 	 * HS/VS, invert VS.
573 	 */
574 	max9286_write(priv, 0x0c, MAX9286_HVEN | MAX9286_DESEL |
575 		      MAX9286_INVVS | MAX9286_HVSRC_D14);
576 }
577 
578 static void max9286_set_fsync_period(struct max9286_priv *priv)
579 {
580 	u32 fsync;
581 
582 	if (!priv->interval.numerator || !priv->interval.denominator) {
583 		/*
584 		 * Special case, a null interval enables automatic FRAMESYNC
585 		 * mode. FRAMESYNC is taken from the slowest link.
586 		 */
587 		max9286_write(priv, 0x01, MAX9286_FSYNCMODE_INT_HIZ |
588 			      MAX9286_FSYNCMETH_AUTO);
589 		return;
590 	}
591 
592 	/*
593 	 * Manual FRAMESYNC
594 	 *
595 	 * The FRAMESYNC generator is configured with a period expressed as a
596 	 * number of PCLK periods.
597 	 */
598 	fsync = div_u64((u64)priv->pixelrate * priv->interval.numerator,
599 			priv->interval.denominator);
600 
601 	dev_dbg(&priv->client->dev, "fsync period %u (pclk %u)\n", fsync,
602 		priv->pixelrate);
603 
604 	max9286_write(priv, 0x01, MAX9286_FSYNCMODE_INT_OUT |
605 		      MAX9286_FSYNCMETH_MANUAL);
606 
607 	max9286_write(priv, 0x06, (fsync >> 0) & 0xff);
608 	max9286_write(priv, 0x07, (fsync >> 8) & 0xff);
609 	max9286_write(priv, 0x08, (fsync >> 16) & 0xff);
610 }
611 
612 /* -----------------------------------------------------------------------------
613  * V4L2 Subdev
614  */
615 
616 static int max9286_set_pixelrate(struct max9286_priv *priv)
617 {
618 	struct max9286_source *source = NULL;
619 	u64 pixelrate = 0;
620 
621 	for_each_source(priv, source) {
622 		struct v4l2_ctrl *ctrl;
623 		u64 source_rate = 0;
624 
625 		/* Pixel rate is mandatory to be reported by sources. */
626 		ctrl = v4l2_ctrl_find(source->sd->ctrl_handler,
627 				      V4L2_CID_PIXEL_RATE);
628 		if (!ctrl) {
629 			pixelrate = 0;
630 			break;
631 		}
632 
633 		/* All source must report the same pixel rate. */
634 		source_rate = v4l2_ctrl_g_ctrl_int64(ctrl);
635 		if (!pixelrate) {
636 			pixelrate = source_rate;
637 		} else if (pixelrate != source_rate) {
638 			dev_err(&priv->client->dev,
639 				"Unable to calculate pixel rate\n");
640 			return -EINVAL;
641 		}
642 	}
643 
644 	if (!pixelrate) {
645 		dev_err(&priv->client->dev,
646 			"No pixel rate control available in sources\n");
647 		return -EINVAL;
648 	}
649 
650 	priv->pixelrate = pixelrate;
651 
652 	/*
653 	 * The CSI-2 transmitter pixel rate is the single source rate multiplied
654 	 * by the number of available sources.
655 	 */
656 	return v4l2_ctrl_s_ctrl_int64(priv->pixelrate_ctrl,
657 				      pixelrate * priv->nsources);
658 }
659 
660 static int max9286_notify_bound(struct v4l2_async_notifier *notifier,
661 				struct v4l2_subdev *subdev,
662 				struct v4l2_async_subdev *asd)
663 {
664 	struct max9286_priv *priv = sd_to_max9286(notifier->sd);
665 	struct max9286_source *source = to_max9286_asd(asd)->source;
666 	unsigned int index = to_index(priv, source);
667 	unsigned int src_pad;
668 	int ret;
669 
670 	ret = media_entity_get_fwnode_pad(&subdev->entity,
671 					  source->fwnode,
672 					  MEDIA_PAD_FL_SOURCE);
673 	if (ret < 0) {
674 		dev_err(&priv->client->dev,
675 			"Failed to find pad for %s\n", subdev->name);
676 		return ret;
677 	}
678 
679 	priv->bound_sources |= BIT(index);
680 	source->sd = subdev;
681 	src_pad = ret;
682 
683 	ret = media_create_pad_link(&source->sd->entity, src_pad,
684 				    &priv->sd.entity, index,
685 				    MEDIA_LNK_FL_ENABLED |
686 				    MEDIA_LNK_FL_IMMUTABLE);
687 	if (ret) {
688 		dev_err(&priv->client->dev,
689 			"Unable to link %s:%u -> %s:%u\n",
690 			source->sd->name, src_pad, priv->sd.name, index);
691 		return ret;
692 	}
693 
694 	dev_dbg(&priv->client->dev, "Bound %s pad: %u on index %u\n",
695 		subdev->name, src_pad, index);
696 
697 	/*
698 	 * As we register a subdev notifiers we won't get a .complete() callback
699 	 * here, so we have to use bound_sources to identify when all remote
700 	 * serializers have probed.
701 	 */
702 	if (priv->bound_sources != priv->source_mask)
703 		return 0;
704 
705 	/*
706 	 * All enabled sources have probed and enabled their reverse control
707 	 * channels:
708 	 *
709 	 * - Increase the reverse channel amplitude to compensate for the
710 	 *   remote ends high threshold
711 	 * - Verify all configuration links are properly detected
712 	 * - Disable auto-ack as communication on the control channel are now
713 	 *   stable.
714 	 */
715 	max9286_reverse_channel_setup(priv, MAX9286_REV_AMP_HIGH);
716 	max9286_check_config_link(priv, priv->source_mask);
717 	max9286_configure_i2c(priv, false);
718 
719 	return max9286_set_pixelrate(priv);
720 }
721 
722 static void max9286_notify_unbind(struct v4l2_async_notifier *notifier,
723 				  struct v4l2_subdev *subdev,
724 				  struct v4l2_async_subdev *asd)
725 {
726 	struct max9286_priv *priv = sd_to_max9286(notifier->sd);
727 	struct max9286_source *source = to_max9286_asd(asd)->source;
728 	unsigned int index = to_index(priv, source);
729 
730 	source->sd = NULL;
731 	priv->bound_sources &= ~BIT(index);
732 }
733 
734 static const struct v4l2_async_notifier_operations max9286_notify_ops = {
735 	.bound = max9286_notify_bound,
736 	.unbind = max9286_notify_unbind,
737 };
738 
739 static int max9286_v4l2_notifier_register(struct max9286_priv *priv)
740 {
741 	struct device *dev = &priv->client->dev;
742 	struct max9286_source *source = NULL;
743 	int ret;
744 
745 	if (!priv->nsources)
746 		return 0;
747 
748 	v4l2_async_nf_init(&priv->notifier);
749 
750 	for_each_source(priv, source) {
751 		unsigned int i = to_index(priv, source);
752 		struct max9286_asd *mas;
753 
754 		mas = v4l2_async_nf_add_fwnode(&priv->notifier, source->fwnode,
755 					       struct max9286_asd);
756 		if (IS_ERR(mas)) {
757 			dev_err(dev, "Failed to add subdev for source %u: %ld",
758 				i, PTR_ERR(mas));
759 			v4l2_async_nf_cleanup(&priv->notifier);
760 			return PTR_ERR(mas);
761 		}
762 
763 		mas->source = source;
764 	}
765 
766 	priv->notifier.ops = &max9286_notify_ops;
767 
768 	ret = v4l2_async_subdev_nf_register(&priv->sd, &priv->notifier);
769 	if (ret) {
770 		dev_err(dev, "Failed to register subdev_notifier");
771 		v4l2_async_nf_cleanup(&priv->notifier);
772 		return ret;
773 	}
774 
775 	return 0;
776 }
777 
778 static void max9286_v4l2_notifier_unregister(struct max9286_priv *priv)
779 {
780 	if (!priv->nsources)
781 		return;
782 
783 	v4l2_async_nf_unregister(&priv->notifier);
784 	v4l2_async_nf_cleanup(&priv->notifier);
785 }
786 
787 static int max9286_s_stream(struct v4l2_subdev *sd, int enable)
788 {
789 	struct max9286_priv *priv = sd_to_max9286(sd);
790 	struct max9286_source *source;
791 	unsigned int i;
792 	bool sync = false;
793 	int ret;
794 
795 	if (enable) {
796 		const struct v4l2_mbus_framefmt *format;
797 
798 		/*
799 		 * Get the format from the first used sink pad, as all sink
800 		 * formats must be identical.
801 		 */
802 		format = &priv->fmt[__ffs(priv->bound_sources)];
803 
804 		max9286_set_video_format(priv, format);
805 		max9286_set_fsync_period(priv);
806 
807 		/*
808 		 * The frame sync between cameras is transmitted across the
809 		 * reverse channel as GPIO. We must open all channels while
810 		 * streaming to allow this synchronisation signal to be shared.
811 		 */
812 		max9286_i2c_mux_open(priv);
813 
814 		/* Start all cameras. */
815 		for_each_source(priv, source) {
816 			ret = v4l2_subdev_call(source->sd, video, s_stream, 1);
817 			if (ret)
818 				return ret;
819 		}
820 
821 		ret = max9286_check_video_links(priv);
822 		if (ret)
823 			return ret;
824 
825 		/*
826 		 * Wait until frame synchronization is locked.
827 		 *
828 		 * Manual says frame sync locking should take ~6 VTS.
829 		 * From practical experience at least 8 are required. Give
830 		 * 12 complete frames time (~400ms at 30 fps) to achieve frame
831 		 * locking before returning error.
832 		 */
833 		for (i = 0; i < 40; i++) {
834 			if (max9286_read(priv, 0x31) & MAX9286_FSYNC_LOCKED) {
835 				sync = true;
836 				break;
837 			}
838 			usleep_range(9000, 11000);
839 		}
840 
841 		if (!sync) {
842 			dev_err(&priv->client->dev,
843 				"Failed to get frame synchronization\n");
844 			return -EXDEV; /* Invalid cross-device link */
845 		}
846 
847 		/*
848 		 * Configure the CSI-2 output to line interleaved mode (W x (N
849 		 * x H), as opposed to the (N x W) x H mode that outputs the
850 		 * images stitched side-by-side) and enable it.
851 		 */
852 		max9286_write(priv, 0x15, MAX9286_CSI_IMAGE_TYP | MAX9286_VCTYPE |
853 			      MAX9286_CSIOUTEN | MAX9286_EN_CCBSYB_CLK_STR |
854 			      MAX9286_EN_GPI_CCBSYB);
855 	} else {
856 		max9286_write(priv, 0x15, MAX9286_VCTYPE |
857 			      MAX9286_EN_CCBSYB_CLK_STR |
858 			      MAX9286_EN_GPI_CCBSYB);
859 
860 		/* Stop all cameras. */
861 		for_each_source(priv, source)
862 			v4l2_subdev_call(source->sd, video, s_stream, 0);
863 
864 		max9286_i2c_mux_close(priv);
865 	}
866 
867 	return 0;
868 }
869 
870 static int max9286_g_frame_interval(struct v4l2_subdev *sd,
871 				    struct v4l2_subdev_frame_interval *interval)
872 {
873 	struct max9286_priv *priv = sd_to_max9286(sd);
874 
875 	if (interval->pad != MAX9286_SRC_PAD)
876 		return -EINVAL;
877 
878 	interval->interval = priv->interval;
879 
880 	return 0;
881 }
882 
883 static int max9286_s_frame_interval(struct v4l2_subdev *sd,
884 				    struct v4l2_subdev_frame_interval *interval)
885 {
886 	struct max9286_priv *priv = sd_to_max9286(sd);
887 
888 	if (interval->pad != MAX9286_SRC_PAD)
889 		return -EINVAL;
890 
891 	priv->interval = interval->interval;
892 
893 	return 0;
894 }
895 
896 static int max9286_enum_mbus_code(struct v4l2_subdev *sd,
897 				  struct v4l2_subdev_state *sd_state,
898 				  struct v4l2_subdev_mbus_code_enum *code)
899 {
900 	if (code->pad || code->index > 0)
901 		return -EINVAL;
902 
903 	code->code = MEDIA_BUS_FMT_UYVY8_1X16;
904 
905 	return 0;
906 }
907 
908 static struct v4l2_mbus_framefmt *
909 max9286_get_pad_format(struct max9286_priv *priv,
910 		       struct v4l2_subdev_state *sd_state,
911 		       unsigned int pad, u32 which)
912 {
913 	switch (which) {
914 	case V4L2_SUBDEV_FORMAT_TRY:
915 		return v4l2_subdev_get_try_format(&priv->sd, sd_state, pad);
916 	case V4L2_SUBDEV_FORMAT_ACTIVE:
917 		return &priv->fmt[pad];
918 	default:
919 		return NULL;
920 	}
921 }
922 
923 static int max9286_set_fmt(struct v4l2_subdev *sd,
924 			   struct v4l2_subdev_state *sd_state,
925 			   struct v4l2_subdev_format *format)
926 {
927 	struct max9286_priv *priv = sd_to_max9286(sd);
928 	struct v4l2_mbus_framefmt *cfg_fmt;
929 	unsigned int i;
930 
931 	if (format->pad == MAX9286_SRC_PAD)
932 		return -EINVAL;
933 
934 	/* Validate the format. */
935 	for (i = 0; i < ARRAY_SIZE(max9286_formats); ++i) {
936 		if (max9286_formats[i].code == format->format.code)
937 			break;
938 	}
939 
940 	if (i == ARRAY_SIZE(max9286_formats))
941 		format->format.code = max9286_formats[0].code;
942 
943 	cfg_fmt = max9286_get_pad_format(priv, sd_state, format->pad,
944 					 format->which);
945 	if (!cfg_fmt)
946 		return -EINVAL;
947 
948 	mutex_lock(&priv->mutex);
949 	*cfg_fmt = format->format;
950 	mutex_unlock(&priv->mutex);
951 
952 	return 0;
953 }
954 
955 static int max9286_get_fmt(struct v4l2_subdev *sd,
956 			   struct v4l2_subdev_state *sd_state,
957 			   struct v4l2_subdev_format *format)
958 {
959 	struct max9286_priv *priv = sd_to_max9286(sd);
960 	struct v4l2_mbus_framefmt *cfg_fmt;
961 	unsigned int pad = format->pad;
962 
963 	/*
964 	 * Multiplexed Stream Support: Support link validation by returning the
965 	 * format of the first bound link. All links must have the same format,
966 	 * as we do not support mixing and matching of cameras connected to the
967 	 * max9286.
968 	 */
969 	if (pad == MAX9286_SRC_PAD)
970 		pad = __ffs(priv->bound_sources);
971 
972 	cfg_fmt = max9286_get_pad_format(priv, sd_state, pad, format->which);
973 	if (!cfg_fmt)
974 		return -EINVAL;
975 
976 	mutex_lock(&priv->mutex);
977 	format->format = *cfg_fmt;
978 	mutex_unlock(&priv->mutex);
979 
980 	return 0;
981 }
982 
983 static const struct v4l2_subdev_video_ops max9286_video_ops = {
984 	.s_stream	= max9286_s_stream,
985 	.g_frame_interval = max9286_g_frame_interval,
986 	.s_frame_interval = max9286_s_frame_interval,
987 };
988 
989 static const struct v4l2_subdev_pad_ops max9286_pad_ops = {
990 	.enum_mbus_code = max9286_enum_mbus_code,
991 	.get_fmt	= max9286_get_fmt,
992 	.set_fmt	= max9286_set_fmt,
993 };
994 
995 static const struct v4l2_subdev_ops max9286_subdev_ops = {
996 	.video		= &max9286_video_ops,
997 	.pad		= &max9286_pad_ops,
998 };
999 
1000 static const struct v4l2_mbus_framefmt max9286_default_format = {
1001 	.width		= 1280,
1002 	.height		= 800,
1003 	.code		= MEDIA_BUS_FMT_UYVY8_1X16,
1004 	.colorspace	= V4L2_COLORSPACE_SRGB,
1005 	.field		= V4L2_FIELD_NONE,
1006 	.ycbcr_enc	= V4L2_YCBCR_ENC_DEFAULT,
1007 	.quantization	= V4L2_QUANTIZATION_DEFAULT,
1008 	.xfer_func	= V4L2_XFER_FUNC_DEFAULT,
1009 };
1010 
1011 static void max9286_init_format(struct v4l2_mbus_framefmt *fmt)
1012 {
1013 	*fmt = max9286_default_format;
1014 }
1015 
1016 static int max9286_open(struct v4l2_subdev *subdev, struct v4l2_subdev_fh *fh)
1017 {
1018 	struct v4l2_mbus_framefmt *format;
1019 	unsigned int i;
1020 
1021 	for (i = 0; i < MAX9286_N_SINKS; i++) {
1022 		format = v4l2_subdev_get_try_format(subdev, fh->state, i);
1023 		max9286_init_format(format);
1024 	}
1025 
1026 	return 0;
1027 }
1028 
1029 static const struct v4l2_subdev_internal_ops max9286_subdev_internal_ops = {
1030 	.open = max9286_open,
1031 };
1032 
1033 static const struct media_entity_operations max9286_media_ops = {
1034 	.link_validate = v4l2_subdev_link_validate
1035 };
1036 
1037 static int max9286_s_ctrl(struct v4l2_ctrl *ctrl)
1038 {
1039 	switch (ctrl->id) {
1040 	case V4L2_CID_PIXEL_RATE:
1041 		return 0;
1042 	default:
1043 		return -EINVAL;
1044 	}
1045 }
1046 
1047 static const struct v4l2_ctrl_ops max9286_ctrl_ops = {
1048 	.s_ctrl = max9286_s_ctrl,
1049 };
1050 
1051 static int max9286_v4l2_register(struct max9286_priv *priv)
1052 {
1053 	struct device *dev = &priv->client->dev;
1054 	struct fwnode_handle *ep;
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 	ep = fwnode_graph_get_endpoint_by_id(dev_fwnode(dev), MAX9286_SRC_PAD,
1097 					     0, 0);
1098 	if (!ep) {
1099 		dev_err(dev, "Unable to retrieve endpoint on \"port@4\"\n");
1100 		ret = -ENOENT;
1101 		goto err_async;
1102 	}
1103 	priv->sd.fwnode = ep;
1104 
1105 	ret = v4l2_async_register_subdev(&priv->sd);
1106 	if (ret < 0) {
1107 		dev_err(dev, "Unable to register subdevice\n");
1108 		goto err_put_node;
1109 	}
1110 
1111 	return 0;
1112 
1113 err_put_node:
1114 	fwnode_handle_put(ep);
1115 err_async:
1116 	v4l2_ctrl_handler_free(&priv->ctrls);
1117 	max9286_v4l2_notifier_unregister(priv);
1118 
1119 	return ret;
1120 }
1121 
1122 static void max9286_v4l2_unregister(struct max9286_priv *priv)
1123 {
1124 	fwnode_handle_put(priv->sd.fwnode);
1125 	v4l2_ctrl_handler_free(&priv->ctrls);
1126 	v4l2_async_unregister_subdev(&priv->sd);
1127 	max9286_v4l2_notifier_unregister(priv);
1128 }
1129 
1130 /* -----------------------------------------------------------------------------
1131  * Probe/Remove
1132  */
1133 
1134 static int max9286_setup(struct max9286_priv *priv)
1135 {
1136 	/*
1137 	 * Link ordering values for all enabled links combinations. Orders must
1138 	 * be assigned sequentially from 0 to the number of enabled links
1139 	 * without leaving any hole for disabled links. We thus assign orders to
1140 	 * enabled links first, and use the remaining order values for disabled
1141 	 * links are all links must have a different order value;
1142 	 */
1143 	static const u8 link_order[] = {
1144 		(3 << 6) | (2 << 4) | (1 << 2) | (0 << 0), /* xxxx */
1145 		(3 << 6) | (2 << 4) | (1 << 2) | (0 << 0), /* xxx0 */
1146 		(3 << 6) | (2 << 4) | (0 << 2) | (1 << 0), /* xx0x */
1147 		(3 << 6) | (2 << 4) | (1 << 2) | (0 << 0), /* xx10 */
1148 		(3 << 6) | (0 << 4) | (2 << 2) | (1 << 0), /* x0xx */
1149 		(3 << 6) | (1 << 4) | (2 << 2) | (0 << 0), /* x1x0 */
1150 		(3 << 6) | (1 << 4) | (0 << 2) | (2 << 0), /* x10x */
1151 		(3 << 6) | (1 << 4) | (1 << 2) | (0 << 0), /* x210 */
1152 		(0 << 6) | (3 << 4) | (2 << 2) | (1 << 0), /* 0xxx */
1153 		(1 << 6) | (3 << 4) | (2 << 2) | (0 << 0), /* 1xx0 */
1154 		(1 << 6) | (3 << 4) | (0 << 2) | (2 << 0), /* 1x0x */
1155 		(2 << 6) | (3 << 4) | (1 << 2) | (0 << 0), /* 2x10 */
1156 		(1 << 6) | (0 << 4) | (3 << 2) | (2 << 0), /* 10xx */
1157 		(2 << 6) | (1 << 4) | (3 << 2) | (0 << 0), /* 21x0 */
1158 		(2 << 6) | (1 << 4) | (0 << 2) | (3 << 0), /* 210x */
1159 		(3 << 6) | (2 << 4) | (1 << 2) | (0 << 0), /* 3210 */
1160 	};
1161 	int cfg;
1162 
1163 	/*
1164 	 * Set the I2C bus speed.
1165 	 *
1166 	 * Enable I2C Local Acknowledge during the probe sequences of the camera
1167 	 * only. This should be disabled after the mux is initialised.
1168 	 */
1169 	max9286_configure_i2c(priv, true);
1170 	max9286_reverse_channel_setup(priv, priv->init_rev_chan_mv);
1171 
1172 	/*
1173 	 * Enable GMSL links, mask unused ones and autodetect link
1174 	 * used as CSI clock source.
1175 	 */
1176 	max9286_write(priv, 0x00, MAX9286_MSTLINKSEL_AUTO | priv->route_mask);
1177 	max9286_write(priv, 0x0b, link_order[priv->route_mask]);
1178 	max9286_write(priv, 0x69, (0xf & ~priv->route_mask));
1179 
1180 	max9286_set_video_format(priv, &max9286_default_format);
1181 	max9286_set_fsync_period(priv);
1182 
1183 	cfg = max9286_read(priv, 0x1c);
1184 	if (cfg < 0)
1185 		return cfg;
1186 
1187 	dev_dbg(&priv->client->dev, "power-up config: %s immunity, %u-bit bus\n",
1188 		cfg & MAX9286_HIGHIMM(0) ? "high" : "legacy",
1189 		cfg & MAX9286_BWS ? 32 : cfg & MAX9286_HIBW ? 27 : 24);
1190 
1191 	if (priv->bus_width) {
1192 		cfg &= ~(MAX9286_HIBW | MAX9286_BWS);
1193 
1194 		if (priv->bus_width == 27)
1195 			cfg |= MAX9286_HIBW;
1196 		else if (priv->bus_width == 32)
1197 			cfg |= MAX9286_BWS;
1198 
1199 		max9286_write(priv, 0x1c, cfg);
1200 	}
1201 
1202 	/*
1203 	 * The overlap window seems to provide additional validation by tracking
1204 	 * the delay between vsync and frame sync, generating an error if the
1205 	 * delay is bigger than the programmed window, though it's not yet clear
1206 	 * what value should be set.
1207 	 *
1208 	 * As it's an optional value and can be disabled, we do so by setting
1209 	 * a 0 overlap value.
1210 	 */
1211 	max9286_write(priv, 0x63, 0);
1212 	max9286_write(priv, 0x64, 0);
1213 
1214 	/*
1215 	 * Wait for 2ms to allow the link to resynchronize after the
1216 	 * configuration change.
1217 	 */
1218 	usleep_range(2000, 5000);
1219 
1220 	return 0;
1221 }
1222 
1223 static int max9286_gpio_set(struct max9286_priv *priv, unsigned int offset,
1224 			    int value)
1225 {
1226 	if (value)
1227 		priv->gpio_state |= BIT(offset);
1228 	else
1229 		priv->gpio_state &= ~BIT(offset);
1230 
1231 	return max9286_write(priv, 0x0f,
1232 			     MAX9286_0X0F_RESERVED | priv->gpio_state);
1233 }
1234 
1235 static void max9286_gpiochip_set(struct gpio_chip *chip,
1236 				 unsigned int offset, int value)
1237 {
1238 	struct max9286_priv *priv = gpiochip_get_data(chip);
1239 
1240 	max9286_gpio_set(priv, offset, value);
1241 }
1242 
1243 static int max9286_gpiochip_get(struct gpio_chip *chip, unsigned int offset)
1244 {
1245 	struct max9286_priv *priv = gpiochip_get_data(chip);
1246 
1247 	return priv->gpio_state & BIT(offset);
1248 }
1249 
1250 static int max9286_register_gpio(struct max9286_priv *priv)
1251 {
1252 	struct device *dev = &priv->client->dev;
1253 	struct gpio_chip *gpio = &priv->gpio;
1254 	int ret;
1255 
1256 	/* Configure the GPIO */
1257 	gpio->label = dev_name(dev);
1258 	gpio->parent = dev;
1259 	gpio->owner = THIS_MODULE;
1260 	gpio->ngpio = 2;
1261 	gpio->base = -1;
1262 	gpio->set = max9286_gpiochip_set;
1263 	gpio->get = max9286_gpiochip_get;
1264 	gpio->can_sleep = true;
1265 
1266 	ret = devm_gpiochip_add_data(dev, gpio, priv);
1267 	if (ret)
1268 		dev_err(dev, "Unable to create gpio_chip\n");
1269 
1270 	return ret;
1271 }
1272 
1273 static int max9286_parse_gpios(struct max9286_priv *priv)
1274 {
1275 	struct device *dev = &priv->client->dev;
1276 	int ret;
1277 
1278 	/*
1279 	 * Parse the "gpio-poc" vendor property. If the property is not
1280 	 * specified the camera power is controlled by a regulator.
1281 	 */
1282 	ret = of_property_read_u32_array(dev->of_node, "maxim,gpio-poc",
1283 					 priv->gpio_poc, 2);
1284 	if (ret == -EINVAL) {
1285 		/*
1286 		 * If gpio lines are not used for the camera power, register
1287 		 * a gpio controller for consumers.
1288 		 */
1289 		return max9286_register_gpio(priv);
1290 	}
1291 
1292 	/* If the property is specified make sure it is well formed. */
1293 	if (ret || priv->gpio_poc[0] > 1 ||
1294 	    (priv->gpio_poc[1] != GPIO_ACTIVE_HIGH &&
1295 	     priv->gpio_poc[1] != GPIO_ACTIVE_LOW)) {
1296 		dev_err(dev, "Invalid 'gpio-poc' property\n");
1297 		return -EINVAL;
1298 	}
1299 
1300 	priv->use_gpio_poc = true;
1301 	return 0;
1302 }
1303 
1304 static int max9286_poc_power_on(struct max9286_priv *priv)
1305 {
1306 	struct max9286_source *source;
1307 	unsigned int enabled = 0;
1308 	int ret;
1309 
1310 	/* Enable the global regulator if available. */
1311 	if (priv->regulator)
1312 		return regulator_enable(priv->regulator);
1313 
1314 	if (priv->use_gpio_poc)
1315 		return max9286_gpio_set(priv, priv->gpio_poc[0],
1316 					!priv->gpio_poc[1]);
1317 
1318 	/* Otherwise use the per-port regulators. */
1319 	for_each_source(priv, source) {
1320 		ret = regulator_enable(source->regulator);
1321 		if (ret < 0)
1322 			goto error;
1323 
1324 		enabled |= BIT(to_index(priv, source));
1325 	}
1326 
1327 	return 0;
1328 
1329 error:
1330 	for_each_source(priv, source) {
1331 		if (enabled & BIT(to_index(priv, source)))
1332 			regulator_disable(source->regulator);
1333 	}
1334 
1335 	return ret;
1336 }
1337 
1338 static int max9286_poc_power_off(struct max9286_priv *priv)
1339 {
1340 	struct max9286_source *source;
1341 	int ret = 0;
1342 
1343 	if (priv->regulator)
1344 		return regulator_disable(priv->regulator);
1345 
1346 	if (priv->use_gpio_poc)
1347 		return max9286_gpio_set(priv, priv->gpio_poc[0],
1348 					priv->gpio_poc[1]);
1349 
1350 	for_each_source(priv, source) {
1351 		int err;
1352 
1353 		err = regulator_disable(source->regulator);
1354 		if (!ret)
1355 			ret = err;
1356 	}
1357 
1358 	return ret;
1359 }
1360 
1361 static int max9286_poc_enable(struct max9286_priv *priv, bool enable)
1362 {
1363 	int ret;
1364 
1365 	if (enable)
1366 		ret = max9286_poc_power_on(priv);
1367 	else
1368 		ret = max9286_poc_power_off(priv);
1369 
1370 	if (ret < 0)
1371 		dev_err(&priv->client->dev, "Unable to turn power %s\n",
1372 			enable ? "on" : "off");
1373 
1374 	return ret;
1375 }
1376 
1377 static int max9286_init(struct max9286_priv *priv)
1378 {
1379 	struct i2c_client *client = priv->client;
1380 	int ret;
1381 
1382 	ret = max9286_poc_enable(priv, true);
1383 	if (ret)
1384 		return ret;
1385 
1386 	ret = max9286_setup(priv);
1387 	if (ret) {
1388 		dev_err(&client->dev, "Unable to setup max9286\n");
1389 		goto err_poc_disable;
1390 	}
1391 
1392 	/*
1393 	 * Register all V4L2 interactions for the MAX9286 and notifiers for
1394 	 * any subdevices connected.
1395 	 */
1396 	ret = max9286_v4l2_register(priv);
1397 	if (ret) {
1398 		dev_err(&client->dev, "Failed to register with V4L2\n");
1399 		goto err_poc_disable;
1400 	}
1401 
1402 	ret = max9286_i2c_mux_init(priv);
1403 	if (ret) {
1404 		dev_err(&client->dev, "Unable to initialize I2C multiplexer\n");
1405 		goto err_v4l2_register;
1406 	}
1407 
1408 	/* Leave the mux channels disabled until they are selected. */
1409 	max9286_i2c_mux_close(priv);
1410 
1411 	return 0;
1412 
1413 err_v4l2_register:
1414 	max9286_v4l2_unregister(priv);
1415 err_poc_disable:
1416 	max9286_poc_enable(priv, false);
1417 
1418 	return ret;
1419 }
1420 
1421 static void max9286_cleanup_dt(struct max9286_priv *priv)
1422 {
1423 	struct max9286_source *source;
1424 
1425 	for_each_source(priv, source) {
1426 		fwnode_handle_put(source->fwnode);
1427 		source->fwnode = NULL;
1428 	}
1429 }
1430 
1431 static int max9286_parse_dt(struct max9286_priv *priv)
1432 {
1433 	struct device *dev = &priv->client->dev;
1434 	struct device_node *i2c_mux;
1435 	struct device_node *node = NULL;
1436 	unsigned int i2c_mux_mask = 0;
1437 	u32 reverse_channel_microvolt;
1438 	u32 i2c_clk_freq = 105000;
1439 	unsigned int i;
1440 
1441 	/* Balance the of_node_put() performed by of_find_node_by_name(). */
1442 	of_node_get(dev->of_node);
1443 	i2c_mux = of_find_node_by_name(dev->of_node, "i2c-mux");
1444 	if (!i2c_mux) {
1445 		dev_err(dev, "Failed to find i2c-mux node\n");
1446 		return -EINVAL;
1447 	}
1448 
1449 	/* Identify which i2c-mux channels are enabled */
1450 	for_each_child_of_node(i2c_mux, node) {
1451 		u32 id = 0;
1452 
1453 		of_property_read_u32(node, "reg", &id);
1454 		if (id >= MAX9286_NUM_GMSL)
1455 			continue;
1456 
1457 		if (!of_device_is_available(node)) {
1458 			dev_dbg(dev, "Skipping disabled I2C bus port %u\n", id);
1459 			continue;
1460 		}
1461 
1462 		i2c_mux_mask |= BIT(id);
1463 	}
1464 	of_node_put(node);
1465 	of_node_put(i2c_mux);
1466 
1467 	/* Parse the endpoints */
1468 	for_each_endpoint_of_node(dev->of_node, node) {
1469 		struct max9286_source *source;
1470 		struct of_endpoint ep;
1471 
1472 		of_graph_parse_endpoint(node, &ep);
1473 		dev_dbg(dev, "Endpoint %pOF on port %d",
1474 			ep.local_node, ep.port);
1475 
1476 		if (ep.port > MAX9286_NUM_GMSL) {
1477 			dev_err(dev, "Invalid endpoint %s on port %d",
1478 				of_node_full_name(ep.local_node), ep.port);
1479 			continue;
1480 		}
1481 
1482 		/* For the source endpoint just parse the bus configuration. */
1483 		if (ep.port == MAX9286_SRC_PAD) {
1484 			struct v4l2_fwnode_endpoint vep = {
1485 				.bus_type = V4L2_MBUS_CSI2_DPHY
1486 			};
1487 			int ret;
1488 
1489 			ret = v4l2_fwnode_endpoint_parse(
1490 					of_fwnode_handle(node), &vep);
1491 			if (ret) {
1492 				of_node_put(node);
1493 				return ret;
1494 			}
1495 
1496 			priv->csi2_data_lanes =
1497 				vep.bus.mipi_csi2.num_data_lanes;
1498 
1499 			continue;
1500 		}
1501 
1502 		/* Skip if the corresponding GMSL link is unavailable. */
1503 		if (!(i2c_mux_mask & BIT(ep.port)))
1504 			continue;
1505 
1506 		if (priv->sources[ep.port].fwnode) {
1507 			dev_err(dev,
1508 				"Multiple port endpoints are not supported: %d",
1509 				ep.port);
1510 
1511 			continue;
1512 		}
1513 
1514 		source = &priv->sources[ep.port];
1515 		source->fwnode = fwnode_graph_get_remote_endpoint(
1516 						of_fwnode_handle(node));
1517 		if (!source->fwnode) {
1518 			dev_err(dev,
1519 				"Endpoint %pOF has no remote endpoint connection\n",
1520 				ep.local_node);
1521 
1522 			continue;
1523 		}
1524 
1525 		priv->source_mask |= BIT(ep.port);
1526 		priv->nsources++;
1527 	}
1528 	of_node_put(node);
1529 
1530 	of_property_read_u32(dev->of_node, "maxim,bus-width", &priv->bus_width);
1531 	switch (priv->bus_width) {
1532 	case 0:
1533 		/*
1534 		 * The property isn't specified in the device tree, the driver
1535 		 * will keep the default value selected by the BWS pin.
1536 		 */
1537 	case 24:
1538 	case 27:
1539 	case 32:
1540 		break;
1541 	default:
1542 		dev_err(dev, "Invalid %s value %u\n", "maxim,bus-width",
1543 			priv->bus_width);
1544 		return -EINVAL;
1545 	}
1546 
1547 	of_property_read_u32(dev->of_node, "maxim,i2c-remote-bus-hz",
1548 			     &i2c_clk_freq);
1549 	for (i = 0; i < ARRAY_SIZE(max9286_i2c_speeds); ++i) {
1550 		const struct max9286_i2c_speed *speed = &max9286_i2c_speeds[i];
1551 
1552 		if (speed->rate == i2c_clk_freq) {
1553 			priv->i2c_mstbt = speed->mstbt;
1554 			break;
1555 		}
1556 	}
1557 
1558 	if (i == ARRAY_SIZE(max9286_i2c_speeds)) {
1559 		dev_err(dev, "Invalid %s value %u\n", "maxim,i2c-remote-bus-hz",
1560 			i2c_clk_freq);
1561 		return -EINVAL;
1562 	}
1563 
1564 	/*
1565 	 * Parse the initial value of the reverse channel amplitude from
1566 	 * the firmware interface and convert it to millivolts.
1567 	 *
1568 	 * Default it to 170mV for backward compatibility with DTBs that do not
1569 	 * provide the property.
1570 	 */
1571 	if (of_property_read_u32(dev->of_node,
1572 				 "maxim,reverse-channel-microvolt",
1573 				 &reverse_channel_microvolt))
1574 		priv->init_rev_chan_mv = 170;
1575 	else
1576 		priv->init_rev_chan_mv = reverse_channel_microvolt / 1000U;
1577 
1578 	priv->route_mask = priv->source_mask;
1579 
1580 	return 0;
1581 }
1582 
1583 static int max9286_get_poc_supplies(struct max9286_priv *priv)
1584 {
1585 	struct device *dev = &priv->client->dev;
1586 	struct max9286_source *source;
1587 	int ret;
1588 
1589 	/* Start by getting the global regulator. */
1590 	priv->regulator = devm_regulator_get_optional(dev, "poc");
1591 	if (!IS_ERR(priv->regulator))
1592 		return 0;
1593 
1594 	if (PTR_ERR(priv->regulator) != -ENODEV)
1595 		return dev_err_probe(dev, PTR_ERR(priv->regulator),
1596 				     "Unable to get PoC regulator\n");
1597 
1598 	/* If there's no global regulator, get per-port regulators. */
1599 	dev_dbg(dev,
1600 		"No global PoC regulator, looking for per-port regulators\n");
1601 	priv->regulator = NULL;
1602 
1603 	for_each_source(priv, source) {
1604 		unsigned int index = to_index(priv, source);
1605 		char name[10];
1606 
1607 		snprintf(name, sizeof(name), "port%u-poc", index);
1608 		source->regulator = devm_regulator_get(dev, name);
1609 		if (IS_ERR(source->regulator)) {
1610 			ret = PTR_ERR(source->regulator);
1611 			dev_err_probe(dev, ret,
1612 				      "Unable to get port %u PoC regulator\n",
1613 				      index);
1614 			return ret;
1615 		}
1616 	}
1617 
1618 	return 0;
1619 }
1620 
1621 static int max9286_probe(struct i2c_client *client)
1622 {
1623 	struct max9286_priv *priv;
1624 	int ret;
1625 
1626 	priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
1627 	if (!priv)
1628 		return -ENOMEM;
1629 
1630 	mutex_init(&priv->mutex);
1631 
1632 	priv->client = client;
1633 
1634 	/* GPIO values default to high */
1635 	priv->gpio_state = BIT(0) | BIT(1);
1636 
1637 	ret = max9286_parse_dt(priv);
1638 	if (ret)
1639 		goto err_cleanup_dt;
1640 
1641 	priv->gpiod_pwdn = devm_gpiod_get_optional(&client->dev, "enable",
1642 						   GPIOD_OUT_HIGH);
1643 	if (IS_ERR(priv->gpiod_pwdn)) {
1644 		ret = PTR_ERR(priv->gpiod_pwdn);
1645 		goto err_cleanup_dt;
1646 	}
1647 
1648 	gpiod_set_consumer_name(priv->gpiod_pwdn, "max9286-pwdn");
1649 	gpiod_set_value_cansleep(priv->gpiod_pwdn, 1);
1650 
1651 	/* Wait at least 4ms before the I2C lines latch to the address */
1652 	if (priv->gpiod_pwdn)
1653 		usleep_range(4000, 5000);
1654 
1655 	/*
1656 	 * The MAX9286 starts by default with all ports enabled, we disable all
1657 	 * ports early to ensure that all channels are disabled if we error out
1658 	 * and keep the bus consistent.
1659 	 */
1660 	max9286_i2c_mux_close(priv);
1661 
1662 	/*
1663 	 * The MAX9286 initialises with auto-acknowledge enabled by default.
1664 	 * This can be invasive to other transactions on the same bus, so
1665 	 * disable it early. It will be enabled only as and when needed.
1666 	 */
1667 	max9286_configure_i2c(priv, false);
1668 
1669 	ret = max9286_parse_gpios(priv);
1670 	if (ret)
1671 		goto err_powerdown;
1672 
1673 	if (!priv->use_gpio_poc) {
1674 		ret = max9286_get_poc_supplies(priv);
1675 		if (ret)
1676 			goto err_cleanup_dt;
1677 	}
1678 
1679 	ret = max9286_init(priv);
1680 	if (ret < 0)
1681 		goto err_cleanup_dt;
1682 
1683 	return 0;
1684 
1685 err_powerdown:
1686 	gpiod_set_value_cansleep(priv->gpiod_pwdn, 0);
1687 err_cleanup_dt:
1688 	max9286_cleanup_dt(priv);
1689 
1690 	return ret;
1691 }
1692 
1693 static void max9286_remove(struct i2c_client *client)
1694 {
1695 	struct max9286_priv *priv = sd_to_max9286(i2c_get_clientdata(client));
1696 
1697 	i2c_mux_del_adapters(priv->mux);
1698 
1699 	max9286_v4l2_unregister(priv);
1700 
1701 	max9286_poc_enable(priv, false);
1702 
1703 	gpiod_set_value_cansleep(priv->gpiod_pwdn, 0);
1704 
1705 	max9286_cleanup_dt(priv);
1706 }
1707 
1708 static const struct of_device_id max9286_dt_ids[] = {
1709 	{ .compatible = "maxim,max9286" },
1710 	{},
1711 };
1712 MODULE_DEVICE_TABLE(of, max9286_dt_ids);
1713 
1714 static struct i2c_driver max9286_i2c_driver = {
1715 	.driver	= {
1716 		.name		= "max9286",
1717 		.of_match_table	= of_match_ptr(max9286_dt_ids),
1718 	},
1719 	.probe_new	= max9286_probe,
1720 	.remove		= max9286_remove,
1721 };
1722 
1723 module_i2c_driver(max9286_i2c_driver);
1724 
1725 MODULE_DESCRIPTION("Maxim MAX9286 GMSL Deserializer Driver");
1726 MODULE_AUTHOR("Jacopo Mondi, Kieran Bingham, Laurent Pinchart, Niklas Söderlund, Vladimir Barinov");
1727 MODULE_LICENSE("GPL");
1728