1 /*
2  * MIPI CSI-2 Receiver Subdev for Freescale i.MX6 SOC.
3  *
4  * Copyright (c) 2012-2017 Mentor Graphics Inc.
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  */
11 #include <linux/clk.h>
12 #include <linux/interrupt.h>
13 #include <linux/io.h>
14 #include <linux/iopoll.h>
15 #include <linux/irq.h>
16 #include <linux/module.h>
17 #include <linux/of_graph.h>
18 #include <linux/platform_device.h>
19 #include <media/v4l2-device.h>
20 #include <media/v4l2-fwnode.h>
21 #include <media/v4l2-subdev.h>
22 #include "imx-media.h"
23 
24 /*
25  * there must be 5 pads: 1 input pad from sensor, and
26  * the 4 virtual channel output pads
27  */
28 #define CSI2_SINK_PAD       0
29 #define CSI2_NUM_SINK_PADS  1
30 #define CSI2_NUM_SRC_PADS   4
31 #define CSI2_NUM_PADS       5
32 
33 /*
34  * The default maximum bit-rate per lane in Mbps, if the
35  * source subdev does not provide V4L2_CID_LINK_FREQ.
36  */
37 #define CSI2_DEFAULT_MAX_MBPS 849
38 
39 struct csi2_dev {
40 	struct device          *dev;
41 	struct v4l2_subdev      sd;
42 	struct media_pad       pad[CSI2_NUM_PADS];
43 	struct clk             *dphy_clk;
44 	struct clk             *pllref_clk;
45 	struct clk             *pix_clk; /* what is this? */
46 	void __iomem           *base;
47 	struct v4l2_fwnode_bus_mipi_csi2 bus;
48 
49 	/* lock to protect all members below */
50 	struct mutex lock;
51 
52 	struct v4l2_mbus_framefmt format_mbus;
53 
54 	int                     stream_count;
55 	struct v4l2_subdev      *src_sd;
56 	bool                    sink_linked[CSI2_NUM_SRC_PADS];
57 };
58 
59 #define DEVICE_NAME "imx6-mipi-csi2"
60 
61 /* Register offsets */
62 #define CSI2_VERSION            0x000
63 #define CSI2_N_LANES            0x004
64 #define CSI2_PHY_SHUTDOWNZ      0x008
65 #define CSI2_DPHY_RSTZ          0x00c
66 #define CSI2_RESETN             0x010
67 #define CSI2_PHY_STATE          0x014
68 #define PHY_STOPSTATEDATA_BIT   4
69 #define PHY_STOPSTATEDATA(n)    BIT(PHY_STOPSTATEDATA_BIT + (n))
70 #define PHY_RXCLKACTIVEHS       BIT(8)
71 #define PHY_RXULPSCLKNOT        BIT(9)
72 #define PHY_STOPSTATECLK        BIT(10)
73 #define CSI2_DATA_IDS_1         0x018
74 #define CSI2_DATA_IDS_2         0x01c
75 #define CSI2_ERR1               0x020
76 #define CSI2_ERR2               0x024
77 #define CSI2_MSK1               0x028
78 #define CSI2_MSK2               0x02c
79 #define CSI2_PHY_TST_CTRL0      0x030
80 #define PHY_TESTCLR		BIT(0)
81 #define PHY_TESTCLK		BIT(1)
82 #define CSI2_PHY_TST_CTRL1      0x034
83 #define PHY_TESTEN		BIT(16)
84 /*
85  * i.MX CSI2IPU Gasket registers follow. The CSI2IPU gasket is
86  * not part of the MIPI CSI-2 core, but its registers fall in the
87  * same register map range.
88  */
89 #define CSI2IPU_GASKET		0xf00
90 #define CSI2IPU_YUV422_YUYV	BIT(2)
91 
92 static inline struct csi2_dev *sd_to_dev(struct v4l2_subdev *sdev)
93 {
94 	return container_of(sdev, struct csi2_dev, sd);
95 }
96 
97 /*
98  * The required sequence of MIPI CSI-2 startup as specified in the i.MX6
99  * reference manual is as follows:
100  *
101  * 1. Deassert presetn signal (global reset).
102  *        It's not clear what this "global reset" signal is (maybe APB
103  *        global reset), but in any case this step would be probably
104  *        be carried out during driver load in csi2_probe().
105  *
106  * 2. Configure MIPI Camera Sensor to put all Tx lanes in LP-11 state.
107  *        This must be carried out by the MIPI sensor's s_power(ON) subdev
108  *        op.
109  *
110  * 3. D-PHY initialization.
111  * 4. CSI2 Controller programming (Set N_LANES, deassert PHY_SHUTDOWNZ,
112  *    deassert PHY_RSTZ, deassert CSI2_RESETN).
113  * 5. Read the PHY status register (PHY_STATE) to confirm that all data and
114  *    clock lanes of the D-PHY are in LP-11 state.
115  * 6. Configure the MIPI Camera Sensor to start transmitting a clock on the
116  *    D-PHY clock lane.
117  * 7. CSI2 Controller programming - Read the PHY status register (PHY_STATE)
118  *    to confirm that the D-PHY is receiving a clock on the D-PHY clock lane.
119  *
120  * All steps 3 through 7 are carried out by csi2_s_stream(ON) here. Step
121  * 6 is accomplished by calling the source subdev's s_stream(ON) between
122  * steps 5 and 7.
123  */
124 
125 static void csi2_enable(struct csi2_dev *csi2, bool enable)
126 {
127 	if (enable) {
128 		writel(0x1, csi2->base + CSI2_PHY_SHUTDOWNZ);
129 		writel(0x1, csi2->base + CSI2_DPHY_RSTZ);
130 		writel(0x1, csi2->base + CSI2_RESETN);
131 	} else {
132 		writel(0x0, csi2->base + CSI2_PHY_SHUTDOWNZ);
133 		writel(0x0, csi2->base + CSI2_DPHY_RSTZ);
134 		writel(0x0, csi2->base + CSI2_RESETN);
135 	}
136 }
137 
138 static void csi2_set_lanes(struct csi2_dev *csi2)
139 {
140 	int lanes = csi2->bus.num_data_lanes;
141 
142 	writel(lanes - 1, csi2->base + CSI2_N_LANES);
143 }
144 
145 static void dw_mipi_csi2_phy_write(struct csi2_dev *csi2,
146 				   u32 test_code, u32 test_data)
147 {
148 	/* Clear PHY test interface */
149 	writel(PHY_TESTCLR, csi2->base + CSI2_PHY_TST_CTRL0);
150 	writel(0x0, csi2->base + CSI2_PHY_TST_CTRL1);
151 	writel(0x0, csi2->base + CSI2_PHY_TST_CTRL0);
152 
153 	/* Raise test interface strobe signal */
154 	writel(PHY_TESTCLK, csi2->base + CSI2_PHY_TST_CTRL0);
155 
156 	/* Configure address write on falling edge and lower strobe signal */
157 	writel(PHY_TESTEN | test_code, csi2->base + CSI2_PHY_TST_CTRL1);
158 	writel(0x0, csi2->base + CSI2_PHY_TST_CTRL0);
159 
160 	/* Configure data write on rising edge and raise strobe signal */
161 	writel(test_data, csi2->base + CSI2_PHY_TST_CTRL1);
162 	writel(PHY_TESTCLK, csi2->base + CSI2_PHY_TST_CTRL0);
163 
164 	/* Clear strobe signal */
165 	writel(0x0, csi2->base + CSI2_PHY_TST_CTRL0);
166 }
167 
168 /*
169  * This table is based on the table documented at
170  * https://community.nxp.com/docs/DOC-94312. It assumes
171  * a 27MHz D-PHY pll reference clock.
172  */
173 static const struct {
174 	u32 max_mbps;
175 	u32 hsfreqrange_sel;
176 } hsfreq_map[] = {
177 	{ 90, 0x00}, {100, 0x20}, {110, 0x40}, {125, 0x02},
178 	{140, 0x22}, {150, 0x42}, {160, 0x04}, {180, 0x24},
179 	{200, 0x44}, {210, 0x06}, {240, 0x26}, {250, 0x46},
180 	{270, 0x08}, {300, 0x28}, {330, 0x48}, {360, 0x2a},
181 	{400, 0x4a}, {450, 0x0c}, {500, 0x2c}, {550, 0x0e},
182 	{600, 0x2e}, {650, 0x10}, {700, 0x30}, {750, 0x12},
183 	{800, 0x32}, {850, 0x14}, {900, 0x34}, {950, 0x54},
184 	{1000, 0x74},
185 };
186 
187 static int max_mbps_to_hsfreqrange_sel(u32 max_mbps)
188 {
189 	int i;
190 
191 	for (i = 0; i < ARRAY_SIZE(hsfreq_map); i++)
192 		if (hsfreq_map[i].max_mbps > max_mbps)
193 			return hsfreq_map[i].hsfreqrange_sel;
194 
195 	return -EINVAL;
196 }
197 
198 static int csi2_dphy_init(struct csi2_dev *csi2)
199 {
200 	struct v4l2_ctrl *ctrl;
201 	u32 mbps_per_lane;
202 	int sel;
203 
204 	ctrl = v4l2_ctrl_find(csi2->src_sd->ctrl_handler,
205 			      V4L2_CID_LINK_FREQ);
206 	if (!ctrl)
207 		mbps_per_lane = CSI2_DEFAULT_MAX_MBPS;
208 	else
209 		mbps_per_lane = DIV_ROUND_UP_ULL(2 * ctrl->qmenu_int[ctrl->val],
210 						 USEC_PER_SEC);
211 
212 	sel = max_mbps_to_hsfreqrange_sel(mbps_per_lane);
213 	if (sel < 0)
214 		return sel;
215 
216 	dw_mipi_csi2_phy_write(csi2, 0x44, sel);
217 
218 	return 0;
219 }
220 
221 /*
222  * Waits for ultra-low-power state on D-PHY clock lane. This is currently
223  * unused and may not be needed at all, but keep around just in case.
224  */
225 static int __maybe_unused csi2_dphy_wait_ulp(struct csi2_dev *csi2)
226 {
227 	u32 reg;
228 	int ret;
229 
230 	/* wait for ULP on clock lane */
231 	ret = readl_poll_timeout(csi2->base + CSI2_PHY_STATE, reg,
232 				 !(reg & PHY_RXULPSCLKNOT), 0, 500000);
233 	if (ret) {
234 		v4l2_err(&csi2->sd, "ULP timeout, phy_state = 0x%08x\n", reg);
235 		return ret;
236 	}
237 
238 	/* wait until no errors on bus */
239 	ret = readl_poll_timeout(csi2->base + CSI2_ERR1, reg,
240 				 reg == 0x0, 0, 500000);
241 	if (ret) {
242 		v4l2_err(&csi2->sd, "stable bus timeout, err1 = 0x%08x\n", reg);
243 		return ret;
244 	}
245 
246 	return 0;
247 }
248 
249 /* Waits for low-power LP-11 state on data and clock lanes. */
250 static int csi2_dphy_wait_stopstate(struct csi2_dev *csi2)
251 {
252 	u32 mask, reg;
253 	int ret;
254 
255 	mask = PHY_STOPSTATECLK | (((1 << csi2->bus.num_data_lanes) - 1) <<
256 				   PHY_STOPSTATEDATA_BIT);
257 
258 	ret = readl_poll_timeout(csi2->base + CSI2_PHY_STATE, reg,
259 				 (reg & mask) == mask, 0, 500000);
260 	if (ret) {
261 		v4l2_err(&csi2->sd, "LP-11 timeout, phy_state = 0x%08x\n", reg);
262 		return ret;
263 	}
264 
265 	return 0;
266 }
267 
268 /* Wait for active clock on the clock lane. */
269 static int csi2_dphy_wait_clock_lane(struct csi2_dev *csi2)
270 {
271 	u32 reg;
272 	int ret;
273 
274 	ret = readl_poll_timeout(csi2->base + CSI2_PHY_STATE, reg,
275 				 (reg & PHY_RXCLKACTIVEHS), 0, 500000);
276 	if (ret) {
277 		v4l2_err(&csi2->sd, "clock lane timeout, phy_state = 0x%08x\n",
278 			 reg);
279 		return ret;
280 	}
281 
282 	return 0;
283 }
284 
285 /* Setup the i.MX CSI2IPU Gasket */
286 static void csi2ipu_gasket_init(struct csi2_dev *csi2)
287 {
288 	u32 reg = 0;
289 
290 	switch (csi2->format_mbus.code) {
291 	case MEDIA_BUS_FMT_YUYV8_2X8:
292 	case MEDIA_BUS_FMT_YUYV8_1X16:
293 		reg = CSI2IPU_YUV422_YUYV;
294 		break;
295 	default:
296 		break;
297 	}
298 
299 	writel(reg, csi2->base + CSI2IPU_GASKET);
300 }
301 
302 static int csi2_start(struct csi2_dev *csi2)
303 {
304 	int ret;
305 
306 	ret = clk_prepare_enable(csi2->pix_clk);
307 	if (ret)
308 		return ret;
309 
310 	/* setup the gasket */
311 	csi2ipu_gasket_init(csi2);
312 
313 	/* Step 3 */
314 	ret = csi2_dphy_init(csi2);
315 	if (ret)
316 		goto err_disable_clk;
317 
318 	/* Step 4 */
319 	csi2_set_lanes(csi2);
320 	csi2_enable(csi2, true);
321 
322 	/* Step 5 */
323 	ret = csi2_dphy_wait_stopstate(csi2);
324 	if (ret)
325 		goto err_assert_reset;
326 
327 	/* Step 6 */
328 	ret = v4l2_subdev_call(csi2->src_sd, video, s_stream, 1);
329 	ret = (ret && ret != -ENOIOCTLCMD) ? ret : 0;
330 	if (ret)
331 		goto err_assert_reset;
332 
333 	/* Step 7 */
334 	ret = csi2_dphy_wait_clock_lane(csi2);
335 	if (ret)
336 		goto err_stop_upstream;
337 
338 	return 0;
339 
340 err_stop_upstream:
341 	v4l2_subdev_call(csi2->src_sd, video, s_stream, 0);
342 err_assert_reset:
343 	csi2_enable(csi2, false);
344 err_disable_clk:
345 	clk_disable_unprepare(csi2->pix_clk);
346 	return ret;
347 }
348 
349 static void csi2_stop(struct csi2_dev *csi2)
350 {
351 	/* stop upstream */
352 	v4l2_subdev_call(csi2->src_sd, video, s_stream, 0);
353 
354 	csi2_enable(csi2, false);
355 	clk_disable_unprepare(csi2->pix_clk);
356 }
357 
358 /*
359  * V4L2 subdev operations.
360  */
361 
362 static int csi2_s_stream(struct v4l2_subdev *sd, int enable)
363 {
364 	struct csi2_dev *csi2 = sd_to_dev(sd);
365 	int i, ret = 0;
366 
367 	mutex_lock(&csi2->lock);
368 
369 	if (!csi2->src_sd) {
370 		ret = -EPIPE;
371 		goto out;
372 	}
373 
374 	for (i = 0; i < CSI2_NUM_SRC_PADS; i++) {
375 		if (csi2->sink_linked[i])
376 			break;
377 	}
378 	if (i >= CSI2_NUM_SRC_PADS) {
379 		ret = -EPIPE;
380 		goto out;
381 	}
382 
383 	/*
384 	 * enable/disable streaming only if stream_count is
385 	 * going from 0 to 1 / 1 to 0.
386 	 */
387 	if (csi2->stream_count != !enable)
388 		goto update_count;
389 
390 	dev_dbg(csi2->dev, "stream %s\n", enable ? "ON" : "OFF");
391 	if (enable)
392 		ret = csi2_start(csi2);
393 	else
394 		csi2_stop(csi2);
395 	if (ret)
396 		goto out;
397 
398 update_count:
399 	csi2->stream_count += enable ? 1 : -1;
400 	if (csi2->stream_count < 0)
401 		csi2->stream_count = 0;
402 out:
403 	mutex_unlock(&csi2->lock);
404 	return ret;
405 }
406 
407 static int csi2_link_setup(struct media_entity *entity,
408 			   const struct media_pad *local,
409 			   const struct media_pad *remote, u32 flags)
410 {
411 	struct v4l2_subdev *sd = media_entity_to_v4l2_subdev(entity);
412 	struct csi2_dev *csi2 = sd_to_dev(sd);
413 	struct v4l2_subdev *remote_sd;
414 	int ret = 0;
415 
416 	dev_dbg(csi2->dev, "link setup %s -> %s", remote->entity->name,
417 		local->entity->name);
418 
419 	remote_sd = media_entity_to_v4l2_subdev(remote->entity);
420 
421 	mutex_lock(&csi2->lock);
422 
423 	if (local->flags & MEDIA_PAD_FL_SOURCE) {
424 		if (flags & MEDIA_LNK_FL_ENABLED) {
425 			if (csi2->sink_linked[local->index - 1]) {
426 				ret = -EBUSY;
427 				goto out;
428 			}
429 			csi2->sink_linked[local->index - 1] = true;
430 		} else {
431 			csi2->sink_linked[local->index - 1] = false;
432 		}
433 	} else {
434 		if (flags & MEDIA_LNK_FL_ENABLED) {
435 			if (csi2->src_sd) {
436 				ret = -EBUSY;
437 				goto out;
438 			}
439 			csi2->src_sd = remote_sd;
440 		} else {
441 			csi2->src_sd = NULL;
442 		}
443 	}
444 
445 out:
446 	mutex_unlock(&csi2->lock);
447 	return ret;
448 }
449 
450 static struct v4l2_mbus_framefmt *
451 __csi2_get_fmt(struct csi2_dev *csi2, struct v4l2_subdev_pad_config *cfg,
452 	       unsigned int pad, enum v4l2_subdev_format_whence which)
453 {
454 	if (which == V4L2_SUBDEV_FORMAT_TRY)
455 		return v4l2_subdev_get_try_format(&csi2->sd, cfg, pad);
456 	else
457 		return &csi2->format_mbus;
458 }
459 
460 static int csi2_get_fmt(struct v4l2_subdev *sd,
461 			struct v4l2_subdev_pad_config *cfg,
462 			struct v4l2_subdev_format *sdformat)
463 {
464 	struct csi2_dev *csi2 = sd_to_dev(sd);
465 	struct v4l2_mbus_framefmt *fmt;
466 
467 	mutex_lock(&csi2->lock);
468 
469 	fmt = __csi2_get_fmt(csi2, cfg, sdformat->pad, sdformat->which);
470 
471 	sdformat->format = *fmt;
472 
473 	mutex_unlock(&csi2->lock);
474 
475 	return 0;
476 }
477 
478 static int csi2_set_fmt(struct v4l2_subdev *sd,
479 			struct v4l2_subdev_pad_config *cfg,
480 			struct v4l2_subdev_format *sdformat)
481 {
482 	struct csi2_dev *csi2 = sd_to_dev(sd);
483 	struct v4l2_mbus_framefmt *fmt;
484 	int ret = 0;
485 
486 	if (sdformat->pad >= CSI2_NUM_PADS)
487 		return -EINVAL;
488 
489 	mutex_lock(&csi2->lock);
490 
491 	if (csi2->stream_count > 0) {
492 		ret = -EBUSY;
493 		goto out;
494 	}
495 
496 	/* Output pads mirror active input pad, no limits on input pads */
497 	if (sdformat->pad != CSI2_SINK_PAD)
498 		sdformat->format = csi2->format_mbus;
499 
500 	fmt = __csi2_get_fmt(csi2, cfg, sdformat->pad, sdformat->which);
501 
502 	*fmt = sdformat->format;
503 out:
504 	mutex_unlock(&csi2->lock);
505 	return ret;
506 }
507 
508 /*
509  * retrieve our pads parsed from the OF graph by the media device
510  */
511 static int csi2_registered(struct v4l2_subdev *sd)
512 {
513 	struct csi2_dev *csi2 = sd_to_dev(sd);
514 	int i, ret;
515 
516 	for (i = 0; i < CSI2_NUM_PADS; i++) {
517 		csi2->pad[i].flags = (i == CSI2_SINK_PAD) ?
518 		MEDIA_PAD_FL_SINK : MEDIA_PAD_FL_SOURCE;
519 	}
520 
521 	/* set a default mbus format  */
522 	ret = imx_media_init_mbus_fmt(&csi2->format_mbus,
523 				      640, 480, 0, V4L2_FIELD_NONE, NULL);
524 	if (ret)
525 		return ret;
526 
527 	return media_entity_pads_init(&sd->entity, CSI2_NUM_PADS, csi2->pad);
528 }
529 
530 static const struct media_entity_operations csi2_entity_ops = {
531 	.link_setup = csi2_link_setup,
532 	.link_validate = v4l2_subdev_link_validate,
533 };
534 
535 static const struct v4l2_subdev_video_ops csi2_video_ops = {
536 	.s_stream = csi2_s_stream,
537 };
538 
539 static const struct v4l2_subdev_pad_ops csi2_pad_ops = {
540 	.init_cfg = imx_media_init_cfg,
541 	.get_fmt = csi2_get_fmt,
542 	.set_fmt = csi2_set_fmt,
543 };
544 
545 static const struct v4l2_subdev_ops csi2_subdev_ops = {
546 	.video = &csi2_video_ops,
547 	.pad = &csi2_pad_ops,
548 };
549 
550 static const struct v4l2_subdev_internal_ops csi2_internal_ops = {
551 	.registered = csi2_registered,
552 };
553 
554 static int csi2_parse_endpoints(struct csi2_dev *csi2)
555 {
556 	struct device_node *node = csi2->dev->of_node;
557 	struct device_node *epnode;
558 	struct v4l2_fwnode_endpoint ep;
559 
560 	epnode = of_graph_get_endpoint_by_regs(node, 0, -1);
561 	if (!epnode) {
562 		v4l2_err(&csi2->sd, "failed to get sink endpoint node\n");
563 		return -EINVAL;
564 	}
565 
566 	v4l2_fwnode_endpoint_parse(of_fwnode_handle(epnode), &ep);
567 	of_node_put(epnode);
568 
569 	if (ep.bus_type != V4L2_MBUS_CSI2) {
570 		v4l2_err(&csi2->sd, "invalid bus type, must be MIPI CSI2\n");
571 		return -EINVAL;
572 	}
573 
574 	csi2->bus = ep.bus.mipi_csi2;
575 
576 	dev_dbg(csi2->dev, "data lanes: %d\n", csi2->bus.num_data_lanes);
577 	dev_dbg(csi2->dev, "flags: 0x%08x\n", csi2->bus.flags);
578 	return 0;
579 }
580 
581 static int csi2_probe(struct platform_device *pdev)
582 {
583 	struct csi2_dev *csi2;
584 	struct resource *res;
585 	int ret;
586 
587 	csi2 = devm_kzalloc(&pdev->dev, sizeof(*csi2), GFP_KERNEL);
588 	if (!csi2)
589 		return -ENOMEM;
590 
591 	csi2->dev = &pdev->dev;
592 
593 	v4l2_subdev_init(&csi2->sd, &csi2_subdev_ops);
594 	v4l2_set_subdevdata(&csi2->sd, &pdev->dev);
595 	csi2->sd.internal_ops = &csi2_internal_ops;
596 	csi2->sd.entity.ops = &csi2_entity_ops;
597 	csi2->sd.dev = &pdev->dev;
598 	csi2->sd.owner = THIS_MODULE;
599 	csi2->sd.flags = V4L2_SUBDEV_FL_HAS_DEVNODE;
600 	strcpy(csi2->sd.name, DEVICE_NAME);
601 	csi2->sd.entity.function = MEDIA_ENT_F_VID_IF_BRIDGE;
602 	csi2->sd.grp_id = IMX_MEDIA_GRP_ID_CSI2;
603 
604 	ret = csi2_parse_endpoints(csi2);
605 	if (ret)
606 		return ret;
607 
608 	csi2->pllref_clk = devm_clk_get(&pdev->dev, "ref");
609 	if (IS_ERR(csi2->pllref_clk)) {
610 		v4l2_err(&csi2->sd, "failed to get pll reference clock\n");
611 		ret = PTR_ERR(csi2->pllref_clk);
612 		return ret;
613 	}
614 
615 	csi2->dphy_clk = devm_clk_get(&pdev->dev, "dphy");
616 	if (IS_ERR(csi2->dphy_clk)) {
617 		v4l2_err(&csi2->sd, "failed to get dphy clock\n");
618 		ret = PTR_ERR(csi2->dphy_clk);
619 		return ret;
620 	}
621 
622 	csi2->pix_clk = devm_clk_get(&pdev->dev, "pix");
623 	if (IS_ERR(csi2->pix_clk)) {
624 		v4l2_err(&csi2->sd, "failed to get pixel clock\n");
625 		ret = PTR_ERR(csi2->pix_clk);
626 		return ret;
627 	}
628 
629 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
630 	if (!res) {
631 		v4l2_err(&csi2->sd, "failed to get platform resources\n");
632 		return -ENODEV;
633 	}
634 
635 	csi2->base = devm_ioremap(&pdev->dev, res->start, PAGE_SIZE);
636 	if (!csi2->base) {
637 		v4l2_err(&csi2->sd, "failed to map CSI-2 registers\n");
638 		return -ENOMEM;
639 	}
640 
641 	mutex_init(&csi2->lock);
642 
643 	ret = clk_prepare_enable(csi2->pllref_clk);
644 	if (ret) {
645 		v4l2_err(&csi2->sd, "failed to enable pllref_clk\n");
646 		goto rmmutex;
647 	}
648 
649 	ret = clk_prepare_enable(csi2->dphy_clk);
650 	if (ret) {
651 		v4l2_err(&csi2->sd, "failed to enable dphy_clk\n");
652 		goto pllref_off;
653 	}
654 
655 	platform_set_drvdata(pdev, &csi2->sd);
656 
657 	ret = v4l2_async_register_subdev(&csi2->sd);
658 	if (ret)
659 		goto dphy_off;
660 
661 	return 0;
662 
663 dphy_off:
664 	clk_disable_unprepare(csi2->dphy_clk);
665 pllref_off:
666 	clk_disable_unprepare(csi2->pllref_clk);
667 rmmutex:
668 	mutex_destroy(&csi2->lock);
669 	return ret;
670 }
671 
672 static int csi2_remove(struct platform_device *pdev)
673 {
674 	struct v4l2_subdev *sd = platform_get_drvdata(pdev);
675 	struct csi2_dev *csi2 = sd_to_dev(sd);
676 
677 	v4l2_async_unregister_subdev(sd);
678 	clk_disable_unprepare(csi2->dphy_clk);
679 	clk_disable_unprepare(csi2->pllref_clk);
680 	mutex_destroy(&csi2->lock);
681 	media_entity_cleanup(&sd->entity);
682 
683 	return 0;
684 }
685 
686 static const struct of_device_id csi2_dt_ids[] = {
687 	{ .compatible = "fsl,imx6-mipi-csi2", },
688 	{ /* sentinel */ }
689 };
690 MODULE_DEVICE_TABLE(of, csi2_dt_ids);
691 
692 static struct platform_driver csi2_driver = {
693 	.driver = {
694 		.name = DEVICE_NAME,
695 		.of_match_table = csi2_dt_ids,
696 	},
697 	.probe = csi2_probe,
698 	.remove = csi2_remove,
699 };
700 
701 module_platform_driver(csi2_driver);
702 
703 MODULE_DESCRIPTION("i.MX5/6 MIPI CSI-2 Receiver driver");
704 MODULE_AUTHOR("Steve Longerbeam <steve_longerbeam@mentor.com>");
705 MODULE_LICENSE("GPL");
706