xref: /openbmc/linux/drivers/gpu/drm/tegra/dpaux.c (revision 6db6b729) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2013 NVIDIA Corporation
4  */
5 
6 #include <linux/clk.h>
7 #include <linux/delay.h>
8 #include <linux/interrupt.h>
9 #include <linux/io.h>
10 #include <linux/module.h>
11 #include <linux/of.h>
12 #include <linux/pinctrl/pinconf-generic.h>
13 #include <linux/pinctrl/pinctrl.h>
14 #include <linux/pinctrl/pinmux.h>
15 #include <linux/platform_device.h>
16 #include <linux/pm_runtime.h>
17 #include <linux/regulator/consumer.h>
18 #include <linux/reset.h>
19 #include <linux/workqueue.h>
20 
21 #include <drm/display/drm_dp_helper.h>
22 #include <drm/display/drm_dp_aux_bus.h>
23 #include <drm/drm_panel.h>
24 
25 #include "dp.h"
26 #include "dpaux.h"
27 #include "drm.h"
28 #include "trace.h"
29 
30 static DEFINE_MUTEX(dpaux_lock);
31 static LIST_HEAD(dpaux_list);
32 
33 struct tegra_dpaux_soc {
34 	unsigned int cmh;
35 	unsigned int drvz;
36 	unsigned int drvi;
37 };
38 
39 struct tegra_dpaux {
40 	struct drm_dp_aux aux;
41 	struct device *dev;
42 
43 	const struct tegra_dpaux_soc *soc;
44 
45 	void __iomem *regs;
46 	int irq;
47 
48 	struct tegra_output *output;
49 
50 	struct reset_control *rst;
51 	struct clk *clk_parent;
52 	struct clk *clk;
53 
54 	struct regulator *vdd;
55 
56 	struct completion complete;
57 	struct work_struct work;
58 	struct list_head list;
59 
60 #ifdef CONFIG_GENERIC_PINCONF
61 	struct pinctrl_dev *pinctrl;
62 	struct pinctrl_desc desc;
63 #endif
64 };
65 
66 static inline struct tegra_dpaux *to_dpaux(struct drm_dp_aux *aux)
67 {
68 	return container_of(aux, struct tegra_dpaux, aux);
69 }
70 
71 static inline struct tegra_dpaux *work_to_dpaux(struct work_struct *work)
72 {
73 	return container_of(work, struct tegra_dpaux, work);
74 }
75 
76 static inline u32 tegra_dpaux_readl(struct tegra_dpaux *dpaux,
77 				    unsigned int offset)
78 {
79 	u32 value = readl(dpaux->regs + (offset << 2));
80 
81 	trace_dpaux_readl(dpaux->dev, offset, value);
82 
83 	return value;
84 }
85 
86 static inline void tegra_dpaux_writel(struct tegra_dpaux *dpaux,
87 				      u32 value, unsigned int offset)
88 {
89 	trace_dpaux_writel(dpaux->dev, offset, value);
90 	writel(value, dpaux->regs + (offset << 2));
91 }
92 
93 static void tegra_dpaux_write_fifo(struct tegra_dpaux *dpaux, const u8 *buffer,
94 				   size_t size)
95 {
96 	size_t i, j;
97 
98 	for (i = 0; i < DIV_ROUND_UP(size, 4); i++) {
99 		size_t num = min_t(size_t, size - i * 4, 4);
100 		u32 value = 0;
101 
102 		for (j = 0; j < num; j++)
103 			value |= buffer[i * 4 + j] << (j * 8);
104 
105 		tegra_dpaux_writel(dpaux, value, DPAUX_DP_AUXDATA_WRITE(i));
106 	}
107 }
108 
109 static void tegra_dpaux_read_fifo(struct tegra_dpaux *dpaux, u8 *buffer,
110 				  size_t size)
111 {
112 	size_t i, j;
113 
114 	for (i = 0; i < DIV_ROUND_UP(size, 4); i++) {
115 		size_t num = min_t(size_t, size - i * 4, 4);
116 		u32 value;
117 
118 		value = tegra_dpaux_readl(dpaux, DPAUX_DP_AUXDATA_READ(i));
119 
120 		for (j = 0; j < num; j++)
121 			buffer[i * 4 + j] = value >> (j * 8);
122 	}
123 }
124 
125 static ssize_t tegra_dpaux_transfer(struct drm_dp_aux *aux,
126 				    struct drm_dp_aux_msg *msg)
127 {
128 	unsigned long timeout = msecs_to_jiffies(250);
129 	struct tegra_dpaux *dpaux = to_dpaux(aux);
130 	unsigned long status;
131 	ssize_t ret = 0;
132 	u8 reply = 0;
133 	u32 value;
134 
135 	/* Tegra has 4x4 byte DP AUX transmit and receive FIFOs. */
136 	if (msg->size > 16)
137 		return -EINVAL;
138 
139 	/*
140 	 * Allow zero-sized messages only for I2C, in which case they specify
141 	 * address-only transactions.
142 	 */
143 	if (msg->size < 1) {
144 		switch (msg->request & ~DP_AUX_I2C_MOT) {
145 		case DP_AUX_I2C_WRITE_STATUS_UPDATE:
146 		case DP_AUX_I2C_WRITE:
147 		case DP_AUX_I2C_READ:
148 			value = DPAUX_DP_AUXCTL_CMD_ADDRESS_ONLY;
149 			break;
150 
151 		default:
152 			return -EINVAL;
153 		}
154 	} else {
155 		/* For non-zero-sized messages, set the CMDLEN field. */
156 		value = DPAUX_DP_AUXCTL_CMDLEN(msg->size - 1);
157 	}
158 
159 	switch (msg->request & ~DP_AUX_I2C_MOT) {
160 	case DP_AUX_I2C_WRITE:
161 		if (msg->request & DP_AUX_I2C_MOT)
162 			value |= DPAUX_DP_AUXCTL_CMD_MOT_WR;
163 		else
164 			value |= DPAUX_DP_AUXCTL_CMD_I2C_WR;
165 
166 		break;
167 
168 	case DP_AUX_I2C_READ:
169 		if (msg->request & DP_AUX_I2C_MOT)
170 			value |= DPAUX_DP_AUXCTL_CMD_MOT_RD;
171 		else
172 			value |= DPAUX_DP_AUXCTL_CMD_I2C_RD;
173 
174 		break;
175 
176 	case DP_AUX_I2C_WRITE_STATUS_UPDATE:
177 		if (msg->request & DP_AUX_I2C_MOT)
178 			value |= DPAUX_DP_AUXCTL_CMD_MOT_RQ;
179 		else
180 			value |= DPAUX_DP_AUXCTL_CMD_I2C_RQ;
181 
182 		break;
183 
184 	case DP_AUX_NATIVE_WRITE:
185 		value |= DPAUX_DP_AUXCTL_CMD_AUX_WR;
186 		break;
187 
188 	case DP_AUX_NATIVE_READ:
189 		value |= DPAUX_DP_AUXCTL_CMD_AUX_RD;
190 		break;
191 
192 	default:
193 		return -EINVAL;
194 	}
195 
196 	tegra_dpaux_writel(dpaux, msg->address, DPAUX_DP_AUXADDR);
197 	tegra_dpaux_writel(dpaux, value, DPAUX_DP_AUXCTL);
198 
199 	if ((msg->request & DP_AUX_I2C_READ) == 0) {
200 		tegra_dpaux_write_fifo(dpaux, msg->buffer, msg->size);
201 		ret = msg->size;
202 	}
203 
204 	/* start transaction */
205 	value = tegra_dpaux_readl(dpaux, DPAUX_DP_AUXCTL);
206 	value |= DPAUX_DP_AUXCTL_TRANSACTREQ;
207 	tegra_dpaux_writel(dpaux, value, DPAUX_DP_AUXCTL);
208 
209 	status = wait_for_completion_timeout(&dpaux->complete, timeout);
210 	if (!status)
211 		return -ETIMEDOUT;
212 
213 	/* read status and clear errors */
214 	value = tegra_dpaux_readl(dpaux, DPAUX_DP_AUXSTAT);
215 	tegra_dpaux_writel(dpaux, 0xf00, DPAUX_DP_AUXSTAT);
216 
217 	if (value & DPAUX_DP_AUXSTAT_TIMEOUT_ERROR)
218 		return -ETIMEDOUT;
219 
220 	if ((value & DPAUX_DP_AUXSTAT_RX_ERROR) ||
221 	    (value & DPAUX_DP_AUXSTAT_SINKSTAT_ERROR) ||
222 	    (value & DPAUX_DP_AUXSTAT_NO_STOP_ERROR))
223 		return -EIO;
224 
225 	switch ((value & DPAUX_DP_AUXSTAT_REPLY_TYPE_MASK) >> 16) {
226 	case 0x00:
227 		reply = DP_AUX_NATIVE_REPLY_ACK;
228 		break;
229 
230 	case 0x01:
231 		reply = DP_AUX_NATIVE_REPLY_NACK;
232 		break;
233 
234 	case 0x02:
235 		reply = DP_AUX_NATIVE_REPLY_DEFER;
236 		break;
237 
238 	case 0x04:
239 		reply = DP_AUX_I2C_REPLY_NACK;
240 		break;
241 
242 	case 0x08:
243 		reply = DP_AUX_I2C_REPLY_DEFER;
244 		break;
245 	}
246 
247 	if ((msg->size > 0) && (msg->reply == DP_AUX_NATIVE_REPLY_ACK)) {
248 		if (msg->request & DP_AUX_I2C_READ) {
249 			size_t count = value & DPAUX_DP_AUXSTAT_REPLY_MASK;
250 
251 			/*
252 			 * There might be a smarter way to do this, but since
253 			 * the DP helpers will already retry transactions for
254 			 * an -EBUSY return value, simply reuse that instead.
255 			 */
256 			if (count != msg->size) {
257 				ret = -EBUSY;
258 				goto out;
259 			}
260 
261 			tegra_dpaux_read_fifo(dpaux, msg->buffer, count);
262 			ret = count;
263 		}
264 	}
265 
266 	msg->reply = reply;
267 
268 out:
269 	return ret;
270 }
271 
272 static void tegra_dpaux_hotplug(struct work_struct *work)
273 {
274 	struct tegra_dpaux *dpaux = work_to_dpaux(work);
275 
276 	if (dpaux->output)
277 		drm_helper_hpd_irq_event(dpaux->output->connector.dev);
278 }
279 
280 static irqreturn_t tegra_dpaux_irq(int irq, void *data)
281 {
282 	struct tegra_dpaux *dpaux = data;
283 	u32 value;
284 
285 	/* clear interrupts */
286 	value = tegra_dpaux_readl(dpaux, DPAUX_INTR_AUX);
287 	tegra_dpaux_writel(dpaux, value, DPAUX_INTR_AUX);
288 
289 	if (value & (DPAUX_INTR_PLUG_EVENT | DPAUX_INTR_UNPLUG_EVENT))
290 		schedule_work(&dpaux->work);
291 
292 	if (value & DPAUX_INTR_IRQ_EVENT) {
293 		/* TODO: handle this */
294 	}
295 
296 	if (value & DPAUX_INTR_AUX_DONE)
297 		complete(&dpaux->complete);
298 
299 	return IRQ_HANDLED;
300 }
301 
302 enum tegra_dpaux_functions {
303 	DPAUX_PADCTL_FUNC_AUX,
304 	DPAUX_PADCTL_FUNC_I2C,
305 	DPAUX_PADCTL_FUNC_OFF,
306 };
307 
308 static void tegra_dpaux_pad_power_down(struct tegra_dpaux *dpaux)
309 {
310 	u32 value = tegra_dpaux_readl(dpaux, DPAUX_HYBRID_SPARE);
311 
312 	value |= DPAUX_HYBRID_SPARE_PAD_POWER_DOWN;
313 
314 	tegra_dpaux_writel(dpaux, value, DPAUX_HYBRID_SPARE);
315 }
316 
317 static void tegra_dpaux_pad_power_up(struct tegra_dpaux *dpaux)
318 {
319 	u32 value = tegra_dpaux_readl(dpaux, DPAUX_HYBRID_SPARE);
320 
321 	value &= ~DPAUX_HYBRID_SPARE_PAD_POWER_DOWN;
322 
323 	tegra_dpaux_writel(dpaux, value, DPAUX_HYBRID_SPARE);
324 }
325 
326 static int tegra_dpaux_pad_config(struct tegra_dpaux *dpaux, unsigned function)
327 {
328 	u32 value;
329 
330 	switch (function) {
331 	case DPAUX_PADCTL_FUNC_AUX:
332 		value = DPAUX_HYBRID_PADCTL_AUX_CMH(dpaux->soc->cmh) |
333 			DPAUX_HYBRID_PADCTL_AUX_DRVZ(dpaux->soc->drvz) |
334 			DPAUX_HYBRID_PADCTL_AUX_DRVI(dpaux->soc->drvi) |
335 			DPAUX_HYBRID_PADCTL_AUX_INPUT_RCV |
336 			DPAUX_HYBRID_PADCTL_MODE_AUX;
337 		break;
338 
339 	case DPAUX_PADCTL_FUNC_I2C:
340 		value = DPAUX_HYBRID_PADCTL_I2C_SDA_INPUT_RCV |
341 			DPAUX_HYBRID_PADCTL_I2C_SCL_INPUT_RCV |
342 			DPAUX_HYBRID_PADCTL_AUX_CMH(dpaux->soc->cmh) |
343 			DPAUX_HYBRID_PADCTL_AUX_DRVZ(dpaux->soc->drvz) |
344 			DPAUX_HYBRID_PADCTL_AUX_DRVI(dpaux->soc->drvi) |
345 			DPAUX_HYBRID_PADCTL_MODE_I2C;
346 		break;
347 
348 	case DPAUX_PADCTL_FUNC_OFF:
349 		tegra_dpaux_pad_power_down(dpaux);
350 		return 0;
351 
352 	default:
353 		return -ENOTSUPP;
354 	}
355 
356 	tegra_dpaux_writel(dpaux, value, DPAUX_HYBRID_PADCTL);
357 	tegra_dpaux_pad_power_up(dpaux);
358 
359 	return 0;
360 }
361 
362 #ifdef CONFIG_GENERIC_PINCONF
363 static const struct pinctrl_pin_desc tegra_dpaux_pins[] = {
364 	PINCTRL_PIN(0, "DP_AUX_CHx_P"),
365 	PINCTRL_PIN(1, "DP_AUX_CHx_N"),
366 };
367 
368 static const unsigned tegra_dpaux_pin_numbers[] = { 0, 1 };
369 
370 static const char * const tegra_dpaux_groups[] = {
371 	"dpaux-io",
372 };
373 
374 static const char * const tegra_dpaux_functions[] = {
375 	"aux",
376 	"i2c",
377 	"off",
378 };
379 
380 static int tegra_dpaux_get_groups_count(struct pinctrl_dev *pinctrl)
381 {
382 	return ARRAY_SIZE(tegra_dpaux_groups);
383 }
384 
385 static const char *tegra_dpaux_get_group_name(struct pinctrl_dev *pinctrl,
386 					      unsigned int group)
387 {
388 	return tegra_dpaux_groups[group];
389 }
390 
391 static int tegra_dpaux_get_group_pins(struct pinctrl_dev *pinctrl,
392 				      unsigned group, const unsigned **pins,
393 				      unsigned *num_pins)
394 {
395 	*pins = tegra_dpaux_pin_numbers;
396 	*num_pins = ARRAY_SIZE(tegra_dpaux_pin_numbers);
397 
398 	return 0;
399 }
400 
401 static const struct pinctrl_ops tegra_dpaux_pinctrl_ops = {
402 	.get_groups_count = tegra_dpaux_get_groups_count,
403 	.get_group_name = tegra_dpaux_get_group_name,
404 	.get_group_pins = tegra_dpaux_get_group_pins,
405 	.dt_node_to_map = pinconf_generic_dt_node_to_map_group,
406 	.dt_free_map = pinconf_generic_dt_free_map,
407 };
408 
409 static int tegra_dpaux_get_functions_count(struct pinctrl_dev *pinctrl)
410 {
411 	return ARRAY_SIZE(tegra_dpaux_functions);
412 }
413 
414 static const char *tegra_dpaux_get_function_name(struct pinctrl_dev *pinctrl,
415 						 unsigned int function)
416 {
417 	return tegra_dpaux_functions[function];
418 }
419 
420 static int tegra_dpaux_get_function_groups(struct pinctrl_dev *pinctrl,
421 					   unsigned int function,
422 					   const char * const **groups,
423 					   unsigned * const num_groups)
424 {
425 	*num_groups = ARRAY_SIZE(tegra_dpaux_groups);
426 	*groups = tegra_dpaux_groups;
427 
428 	return 0;
429 }
430 
431 static int tegra_dpaux_set_mux(struct pinctrl_dev *pinctrl,
432 			       unsigned int function, unsigned int group)
433 {
434 	struct tegra_dpaux *dpaux = pinctrl_dev_get_drvdata(pinctrl);
435 
436 	return tegra_dpaux_pad_config(dpaux, function);
437 }
438 
439 static const struct pinmux_ops tegra_dpaux_pinmux_ops = {
440 	.get_functions_count = tegra_dpaux_get_functions_count,
441 	.get_function_name = tegra_dpaux_get_function_name,
442 	.get_function_groups = tegra_dpaux_get_function_groups,
443 	.set_mux = tegra_dpaux_set_mux,
444 };
445 #endif
446 
447 static int tegra_dpaux_probe(struct platform_device *pdev)
448 {
449 	struct tegra_dpaux *dpaux;
450 	u32 value;
451 	int err;
452 
453 	dpaux = devm_kzalloc(&pdev->dev, sizeof(*dpaux), GFP_KERNEL);
454 	if (!dpaux)
455 		return -ENOMEM;
456 
457 	dpaux->soc = of_device_get_match_data(&pdev->dev);
458 	INIT_WORK(&dpaux->work, tegra_dpaux_hotplug);
459 	init_completion(&dpaux->complete);
460 	INIT_LIST_HEAD(&dpaux->list);
461 	dpaux->dev = &pdev->dev;
462 
463 	dpaux->regs = devm_platform_ioremap_resource(pdev, 0);
464 	if (IS_ERR(dpaux->regs))
465 		return PTR_ERR(dpaux->regs);
466 
467 	dpaux->irq = platform_get_irq(pdev, 0);
468 	if (dpaux->irq < 0)
469 		return dpaux->irq;
470 
471 	if (!pdev->dev.pm_domain) {
472 		dpaux->rst = devm_reset_control_get(&pdev->dev, "dpaux");
473 		if (IS_ERR(dpaux->rst)) {
474 			dev_err(&pdev->dev,
475 				"failed to get reset control: %ld\n",
476 				PTR_ERR(dpaux->rst));
477 			return PTR_ERR(dpaux->rst);
478 		}
479 	}
480 
481 	dpaux->clk = devm_clk_get(&pdev->dev, NULL);
482 	if (IS_ERR(dpaux->clk)) {
483 		dev_err(&pdev->dev, "failed to get module clock: %ld\n",
484 			PTR_ERR(dpaux->clk));
485 		return PTR_ERR(dpaux->clk);
486 	}
487 
488 	dpaux->clk_parent = devm_clk_get(&pdev->dev, "parent");
489 	if (IS_ERR(dpaux->clk_parent)) {
490 		dev_err(&pdev->dev, "failed to get parent clock: %ld\n",
491 			PTR_ERR(dpaux->clk_parent));
492 		return PTR_ERR(dpaux->clk_parent);
493 	}
494 
495 	err = clk_set_rate(dpaux->clk_parent, 270000000);
496 	if (err < 0) {
497 		dev_err(&pdev->dev, "failed to set clock to 270 MHz: %d\n",
498 			err);
499 		return err;
500 	}
501 
502 	dpaux->vdd = devm_regulator_get_optional(&pdev->dev, "vdd");
503 	if (IS_ERR(dpaux->vdd)) {
504 		if (PTR_ERR(dpaux->vdd) != -ENODEV) {
505 			if (PTR_ERR(dpaux->vdd) != -EPROBE_DEFER)
506 				dev_err(&pdev->dev,
507 					"failed to get VDD supply: %ld\n",
508 					PTR_ERR(dpaux->vdd));
509 
510 			return PTR_ERR(dpaux->vdd);
511 		}
512 
513 		dpaux->vdd = NULL;
514 	}
515 
516 	platform_set_drvdata(pdev, dpaux);
517 	pm_runtime_enable(&pdev->dev);
518 	pm_runtime_get_sync(&pdev->dev);
519 
520 	err = devm_request_irq(dpaux->dev, dpaux->irq, tegra_dpaux_irq, 0,
521 			       dev_name(dpaux->dev), dpaux);
522 	if (err < 0) {
523 		dev_err(dpaux->dev, "failed to request IRQ#%u: %d\n",
524 			dpaux->irq, err);
525 		return err;
526 	}
527 
528 	disable_irq(dpaux->irq);
529 
530 	dpaux->aux.transfer = tegra_dpaux_transfer;
531 	dpaux->aux.dev = &pdev->dev;
532 
533 	drm_dp_aux_init(&dpaux->aux);
534 
535 	/*
536 	 * Assume that by default the DPAUX/I2C pads will be used for HDMI,
537 	 * so power them up and configure them in I2C mode.
538 	 *
539 	 * The DPAUX code paths reconfigure the pads in AUX mode, but there
540 	 * is no possibility to perform the I2C mode configuration in the
541 	 * HDMI path.
542 	 */
543 	err = tegra_dpaux_pad_config(dpaux, DPAUX_PADCTL_FUNC_I2C);
544 	if (err < 0)
545 		return err;
546 
547 #ifdef CONFIG_GENERIC_PINCONF
548 	dpaux->desc.name = dev_name(&pdev->dev);
549 	dpaux->desc.pins = tegra_dpaux_pins;
550 	dpaux->desc.npins = ARRAY_SIZE(tegra_dpaux_pins);
551 	dpaux->desc.pctlops = &tegra_dpaux_pinctrl_ops;
552 	dpaux->desc.pmxops = &tegra_dpaux_pinmux_ops;
553 	dpaux->desc.owner = THIS_MODULE;
554 
555 	dpaux->pinctrl = devm_pinctrl_register(&pdev->dev, &dpaux->desc, dpaux);
556 	if (IS_ERR(dpaux->pinctrl)) {
557 		dev_err(&pdev->dev, "failed to register pincontrol\n");
558 		return PTR_ERR(dpaux->pinctrl);
559 	}
560 #endif
561 	/* enable and clear all interrupts */
562 	value = DPAUX_INTR_AUX_DONE | DPAUX_INTR_IRQ_EVENT |
563 		DPAUX_INTR_UNPLUG_EVENT | DPAUX_INTR_PLUG_EVENT;
564 	tegra_dpaux_writel(dpaux, value, DPAUX_INTR_EN_AUX);
565 	tegra_dpaux_writel(dpaux, value, DPAUX_INTR_AUX);
566 
567 	mutex_lock(&dpaux_lock);
568 	list_add_tail(&dpaux->list, &dpaux_list);
569 	mutex_unlock(&dpaux_lock);
570 
571 	err = devm_of_dp_aux_populate_ep_devices(&dpaux->aux);
572 	if (err < 0) {
573 		dev_err(dpaux->dev, "failed to populate AUX bus: %d\n", err);
574 		return err;
575 	}
576 
577 	return 0;
578 }
579 
580 static void tegra_dpaux_remove(struct platform_device *pdev)
581 {
582 	struct tegra_dpaux *dpaux = platform_get_drvdata(pdev);
583 
584 	cancel_work_sync(&dpaux->work);
585 
586 	/* make sure pads are powered down when not in use */
587 	tegra_dpaux_pad_power_down(dpaux);
588 
589 	pm_runtime_put_sync(&pdev->dev);
590 	pm_runtime_disable(&pdev->dev);
591 
592 	mutex_lock(&dpaux_lock);
593 	list_del(&dpaux->list);
594 	mutex_unlock(&dpaux_lock);
595 }
596 
597 static int tegra_dpaux_suspend(struct device *dev)
598 {
599 	struct tegra_dpaux *dpaux = dev_get_drvdata(dev);
600 	int err = 0;
601 
602 	if (dpaux->rst) {
603 		err = reset_control_assert(dpaux->rst);
604 		if (err < 0) {
605 			dev_err(dev, "failed to assert reset: %d\n", err);
606 			return err;
607 		}
608 	}
609 
610 	usleep_range(1000, 2000);
611 
612 	clk_disable_unprepare(dpaux->clk_parent);
613 	clk_disable_unprepare(dpaux->clk);
614 
615 	return err;
616 }
617 
618 static int tegra_dpaux_resume(struct device *dev)
619 {
620 	struct tegra_dpaux *dpaux = dev_get_drvdata(dev);
621 	int err;
622 
623 	err = clk_prepare_enable(dpaux->clk);
624 	if (err < 0) {
625 		dev_err(dev, "failed to enable clock: %d\n", err);
626 		return err;
627 	}
628 
629 	err = clk_prepare_enable(dpaux->clk_parent);
630 	if (err < 0) {
631 		dev_err(dev, "failed to enable parent clock: %d\n", err);
632 		goto disable_clk;
633 	}
634 
635 	usleep_range(1000, 2000);
636 
637 	if (dpaux->rst) {
638 		err = reset_control_deassert(dpaux->rst);
639 		if (err < 0) {
640 			dev_err(dev, "failed to deassert reset: %d\n", err);
641 			goto disable_parent;
642 		}
643 
644 		usleep_range(1000, 2000);
645 	}
646 
647 	return 0;
648 
649 disable_parent:
650 	clk_disable_unprepare(dpaux->clk_parent);
651 disable_clk:
652 	clk_disable_unprepare(dpaux->clk);
653 	return err;
654 }
655 
656 static const struct dev_pm_ops tegra_dpaux_pm_ops = {
657 	RUNTIME_PM_OPS(tegra_dpaux_suspend, tegra_dpaux_resume, NULL)
658 };
659 
660 static const struct tegra_dpaux_soc tegra124_dpaux_soc = {
661 	.cmh = 0x02,
662 	.drvz = 0x04,
663 	.drvi = 0x18,
664 };
665 
666 static const struct tegra_dpaux_soc tegra210_dpaux_soc = {
667 	.cmh = 0x02,
668 	.drvz = 0x04,
669 	.drvi = 0x30,
670 };
671 
672 static const struct tegra_dpaux_soc tegra194_dpaux_soc = {
673 	.cmh = 0x02,
674 	.drvz = 0x04,
675 	.drvi = 0x2c,
676 };
677 
678 static const struct of_device_id tegra_dpaux_of_match[] = {
679 	{ .compatible = "nvidia,tegra194-dpaux", .data = &tegra194_dpaux_soc },
680 	{ .compatible = "nvidia,tegra186-dpaux", .data = &tegra210_dpaux_soc },
681 	{ .compatible = "nvidia,tegra210-dpaux", .data = &tegra210_dpaux_soc },
682 	{ .compatible = "nvidia,tegra124-dpaux", .data = &tegra124_dpaux_soc },
683 	{ },
684 };
685 MODULE_DEVICE_TABLE(of, tegra_dpaux_of_match);
686 
687 struct platform_driver tegra_dpaux_driver = {
688 	.driver = {
689 		.name = "tegra-dpaux",
690 		.of_match_table = tegra_dpaux_of_match,
691 		.pm = pm_ptr(&tegra_dpaux_pm_ops),
692 	},
693 	.probe = tegra_dpaux_probe,
694 	.remove_new = tegra_dpaux_remove,
695 };
696 
697 struct drm_dp_aux *drm_dp_aux_find_by_of_node(struct device_node *np)
698 {
699 	struct tegra_dpaux *dpaux;
700 
701 	mutex_lock(&dpaux_lock);
702 
703 	list_for_each_entry(dpaux, &dpaux_list, list)
704 		if (np == dpaux->dev->of_node) {
705 			mutex_unlock(&dpaux_lock);
706 			return &dpaux->aux;
707 		}
708 
709 	mutex_unlock(&dpaux_lock);
710 
711 	return NULL;
712 }
713 
714 int drm_dp_aux_attach(struct drm_dp_aux *aux, struct tegra_output *output)
715 {
716 	struct tegra_dpaux *dpaux = to_dpaux(aux);
717 	unsigned long timeout;
718 	int err;
719 
720 	aux->drm_dev = output->connector.dev;
721 	err = drm_dp_aux_register(aux);
722 	if (err < 0)
723 		return err;
724 
725 	output->connector.polled = DRM_CONNECTOR_POLL_HPD;
726 	dpaux->output = output;
727 
728 	if (output->panel) {
729 		enum drm_connector_status status;
730 
731 		if (dpaux->vdd) {
732 			err = regulator_enable(dpaux->vdd);
733 			if (err < 0)
734 				return err;
735 		}
736 
737 		timeout = jiffies + msecs_to_jiffies(250);
738 
739 		while (time_before(jiffies, timeout)) {
740 			status = drm_dp_aux_detect(aux);
741 
742 			if (status == connector_status_connected)
743 				break;
744 
745 			usleep_range(1000, 2000);
746 		}
747 
748 		if (status != connector_status_connected)
749 			return -ETIMEDOUT;
750 	}
751 
752 	enable_irq(dpaux->irq);
753 	return 0;
754 }
755 
756 int drm_dp_aux_detach(struct drm_dp_aux *aux)
757 {
758 	struct tegra_dpaux *dpaux = to_dpaux(aux);
759 	unsigned long timeout;
760 	int err;
761 
762 	drm_dp_aux_unregister(aux);
763 	disable_irq(dpaux->irq);
764 
765 	if (dpaux->output->panel) {
766 		enum drm_connector_status status;
767 
768 		if (dpaux->vdd) {
769 			err = regulator_disable(dpaux->vdd);
770 			if (err < 0)
771 				return err;
772 		}
773 
774 		timeout = jiffies + msecs_to_jiffies(250);
775 
776 		while (time_before(jiffies, timeout)) {
777 			status = drm_dp_aux_detect(aux);
778 
779 			if (status == connector_status_disconnected)
780 				break;
781 
782 			usleep_range(1000, 2000);
783 		}
784 
785 		if (status != connector_status_disconnected)
786 			return -ETIMEDOUT;
787 
788 		dpaux->output = NULL;
789 	}
790 
791 	return 0;
792 }
793 
794 enum drm_connector_status drm_dp_aux_detect(struct drm_dp_aux *aux)
795 {
796 	struct tegra_dpaux *dpaux = to_dpaux(aux);
797 	u32 value;
798 
799 	value = tegra_dpaux_readl(dpaux, DPAUX_DP_AUXSTAT);
800 
801 	if (value & DPAUX_DP_AUXSTAT_HPD_STATUS)
802 		return connector_status_connected;
803 
804 	return connector_status_disconnected;
805 }
806 
807 int drm_dp_aux_enable(struct drm_dp_aux *aux)
808 {
809 	struct tegra_dpaux *dpaux = to_dpaux(aux);
810 
811 	return tegra_dpaux_pad_config(dpaux, DPAUX_PADCTL_FUNC_AUX);
812 }
813 
814 int drm_dp_aux_disable(struct drm_dp_aux *aux)
815 {
816 	struct tegra_dpaux *dpaux = to_dpaux(aux);
817 
818 	tegra_dpaux_pad_power_down(dpaux);
819 
820 	return 0;
821 }
822