xref: /linux/drivers/gpu/drm/tegra/dpaux.c (revision a2cce7a9f1b8cc3d4edce106fb971529f1d4d9ce) 
1 /*
2  * Copyright (C) 2013 NVIDIA Corporation
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License version 2 as
6  * published by the Free Software Foundation.
7  */
8 
9 #include <linux/clk.h>
10 #include <linux/delay.h>
11 #include <linux/gpio.h>
12 #include <linux/interrupt.h>
13 #include <linux/io.h>
14 #include <linux/of_gpio.h>
15 #include <linux/platform_device.h>
16 #include <linux/reset.h>
17 #include <linux/regulator/consumer.h>
18 #include <linux/workqueue.h>
19 
20 #include <drm/drm_dp_helper.h>
21 #include <drm/drm_panel.h>
22 
23 #include "dpaux.h"
24 #include "drm.h"
25 
26 static DEFINE_MUTEX(dpaux_lock);
27 static LIST_HEAD(dpaux_list);
28 
29 struct tegra_dpaux {
30 	struct drm_dp_aux aux;
31 	struct device *dev;
32 
33 	void __iomem *regs;
34 	int irq;
35 
36 	struct tegra_output *output;
37 
38 	struct reset_control *rst;
39 	struct clk *clk_parent;
40 	struct clk *clk;
41 
42 	struct regulator *vdd;
43 
44 	struct completion complete;
45 	struct work_struct work;
46 	struct list_head list;
47 };
48 
49 static inline struct tegra_dpaux *to_dpaux(struct drm_dp_aux *aux)
50 {
51 	return container_of(aux, struct tegra_dpaux, aux);
52 }
53 
54 static inline struct tegra_dpaux *work_to_dpaux(struct work_struct *work)
55 {
56 	return container_of(work, struct tegra_dpaux, work);
57 }
58 
59 static inline u32 tegra_dpaux_readl(struct tegra_dpaux *dpaux,
60 				    unsigned long offset)
61 {
62 	return readl(dpaux->regs + (offset << 2));
63 }
64 
65 static inline void tegra_dpaux_writel(struct tegra_dpaux *dpaux,
66 				      u32 value, unsigned long offset)
67 {
68 	writel(value, dpaux->regs + (offset << 2));
69 }
70 
71 static void tegra_dpaux_write_fifo(struct tegra_dpaux *dpaux, const u8 *buffer,
72 				   size_t size)
73 {
74 	size_t i, j;
75 
76 	for (i = 0; i < DIV_ROUND_UP(size, 4); i++) {
77 		size_t num = min_t(size_t, size - i * 4, 4);
78 		u32 value = 0;
79 
80 		for (j = 0; j < num; j++)
81 			value |= buffer[i * 4 + j] << (j * 8);
82 
83 		tegra_dpaux_writel(dpaux, value, DPAUX_DP_AUXDATA_WRITE(i));
84 	}
85 }
86 
87 static void tegra_dpaux_read_fifo(struct tegra_dpaux *dpaux, u8 *buffer,
88 				  size_t size)
89 {
90 	size_t i, j;
91 
92 	for (i = 0; i < DIV_ROUND_UP(size, 4); i++) {
93 		size_t num = min_t(size_t, size - i * 4, 4);
94 		u32 value;
95 
96 		value = tegra_dpaux_readl(dpaux, DPAUX_DP_AUXDATA_READ(i));
97 
98 		for (j = 0; j < num; j++)
99 			buffer[i * 4 + j] = value >> (j * 8);
100 	}
101 }
102 
103 static ssize_t tegra_dpaux_transfer(struct drm_dp_aux *aux,
104 				    struct drm_dp_aux_msg *msg)
105 {
106 	unsigned long timeout = msecs_to_jiffies(250);
107 	struct tegra_dpaux *dpaux = to_dpaux(aux);
108 	unsigned long status;
109 	ssize_t ret = 0;
110 	u32 value;
111 
112 	/* Tegra has 4x4 byte DP AUX transmit and receive FIFOs. */
113 	if (msg->size > 16)
114 		return -EINVAL;
115 
116 	/*
117 	 * Allow zero-sized messages only for I2C, in which case they specify
118 	 * address-only transactions.
119 	 */
120 	if (msg->size < 1) {
121 		switch (msg->request & ~DP_AUX_I2C_MOT) {
122 		case DP_AUX_I2C_WRITE:
123 		case DP_AUX_I2C_READ:
124 			value = DPAUX_DP_AUXCTL_CMD_ADDRESS_ONLY;
125 			break;
126 
127 		default:
128 			return -EINVAL;
129 		}
130 	} else {
131 		/* For non-zero-sized messages, set the CMDLEN field. */
132 		value = DPAUX_DP_AUXCTL_CMDLEN(msg->size - 1);
133 	}
134 
135 	switch (msg->request & ~DP_AUX_I2C_MOT) {
136 	case DP_AUX_I2C_WRITE:
137 		if (msg->request & DP_AUX_I2C_MOT)
138 			value |= DPAUX_DP_AUXCTL_CMD_MOT_WR;
139 		else
140 			value |= DPAUX_DP_AUXCTL_CMD_I2C_WR;
141 
142 		break;
143 
144 	case DP_AUX_I2C_READ:
145 		if (msg->request & DP_AUX_I2C_MOT)
146 			value |= DPAUX_DP_AUXCTL_CMD_MOT_RD;
147 		else
148 			value |= DPAUX_DP_AUXCTL_CMD_I2C_RD;
149 
150 		break;
151 
152 	case DP_AUX_I2C_STATUS:
153 		if (msg->request & DP_AUX_I2C_MOT)
154 			value |= DPAUX_DP_AUXCTL_CMD_MOT_RQ;
155 		else
156 			value |= DPAUX_DP_AUXCTL_CMD_I2C_RQ;
157 
158 		break;
159 
160 	case DP_AUX_NATIVE_WRITE:
161 		value |= DPAUX_DP_AUXCTL_CMD_AUX_WR;
162 		break;
163 
164 	case DP_AUX_NATIVE_READ:
165 		value |= DPAUX_DP_AUXCTL_CMD_AUX_RD;
166 		break;
167 
168 	default:
169 		return -EINVAL;
170 	}
171 
172 	tegra_dpaux_writel(dpaux, msg->address, DPAUX_DP_AUXADDR);
173 	tegra_dpaux_writel(dpaux, value, DPAUX_DP_AUXCTL);
174 
175 	if ((msg->request & DP_AUX_I2C_READ) == 0) {
176 		tegra_dpaux_write_fifo(dpaux, msg->buffer, msg->size);
177 		ret = msg->size;
178 	}
179 
180 	/* start transaction */
181 	value = tegra_dpaux_readl(dpaux, DPAUX_DP_AUXCTL);
182 	value |= DPAUX_DP_AUXCTL_TRANSACTREQ;
183 	tegra_dpaux_writel(dpaux, value, DPAUX_DP_AUXCTL);
184 
185 	status = wait_for_completion_timeout(&dpaux->complete, timeout);
186 	if (!status)
187 		return -ETIMEDOUT;
188 
189 	/* read status and clear errors */
190 	value = tegra_dpaux_readl(dpaux, DPAUX_DP_AUXSTAT);
191 	tegra_dpaux_writel(dpaux, 0xf00, DPAUX_DP_AUXSTAT);
192 
193 	if (value & DPAUX_DP_AUXSTAT_TIMEOUT_ERROR)
194 		return -ETIMEDOUT;
195 
196 	if ((value & DPAUX_DP_AUXSTAT_RX_ERROR) ||
197 	    (value & DPAUX_DP_AUXSTAT_SINKSTAT_ERROR) ||
198 	    (value & DPAUX_DP_AUXSTAT_NO_STOP_ERROR))
199 		return -EIO;
200 
201 	switch ((value & DPAUX_DP_AUXSTAT_REPLY_TYPE_MASK) >> 16) {
202 	case 0x00:
203 		msg->reply = DP_AUX_NATIVE_REPLY_ACK;
204 		break;
205 
206 	case 0x01:
207 		msg->reply = DP_AUX_NATIVE_REPLY_NACK;
208 		break;
209 
210 	case 0x02:
211 		msg->reply = DP_AUX_NATIVE_REPLY_DEFER;
212 		break;
213 
214 	case 0x04:
215 		msg->reply = DP_AUX_I2C_REPLY_NACK;
216 		break;
217 
218 	case 0x08:
219 		msg->reply = DP_AUX_I2C_REPLY_DEFER;
220 		break;
221 	}
222 
223 	if ((msg->size > 0) && (msg->reply == DP_AUX_NATIVE_REPLY_ACK)) {
224 		if (msg->request & DP_AUX_I2C_READ) {
225 			size_t count = value & DPAUX_DP_AUXSTAT_REPLY_MASK;
226 
227 			if (WARN_ON(count != msg->size))
228 				count = min_t(size_t, count, msg->size);
229 
230 			tegra_dpaux_read_fifo(dpaux, msg->buffer, count);
231 			ret = count;
232 		}
233 	}
234 
235 	return ret;
236 }
237 
238 static void tegra_dpaux_hotplug(struct work_struct *work)
239 {
240 	struct tegra_dpaux *dpaux = work_to_dpaux(work);
241 
242 	if (dpaux->output)
243 		drm_helper_hpd_irq_event(dpaux->output->connector.dev);
244 }
245 
246 static irqreturn_t tegra_dpaux_irq(int irq, void *data)
247 {
248 	struct tegra_dpaux *dpaux = data;
249 	irqreturn_t ret = IRQ_HANDLED;
250 	u32 value;
251 
252 	/* clear interrupts */
253 	value = tegra_dpaux_readl(dpaux, DPAUX_INTR_AUX);
254 	tegra_dpaux_writel(dpaux, value, DPAUX_INTR_AUX);
255 
256 	if (value & (DPAUX_INTR_PLUG_EVENT | DPAUX_INTR_UNPLUG_EVENT))
257 		schedule_work(&dpaux->work);
258 
259 	if (value & DPAUX_INTR_IRQ_EVENT) {
260 		/* TODO: handle this */
261 	}
262 
263 	if (value & DPAUX_INTR_AUX_DONE)
264 		complete(&dpaux->complete);
265 
266 	return ret;
267 }
268 
269 static int tegra_dpaux_probe(struct platform_device *pdev)
270 {
271 	struct tegra_dpaux *dpaux;
272 	struct resource *regs;
273 	u32 value;
274 	int err;
275 
276 	dpaux = devm_kzalloc(&pdev->dev, sizeof(*dpaux), GFP_KERNEL);
277 	if (!dpaux)
278 		return -ENOMEM;
279 
280 	INIT_WORK(&dpaux->work, tegra_dpaux_hotplug);
281 	init_completion(&dpaux->complete);
282 	INIT_LIST_HEAD(&dpaux->list);
283 	dpaux->dev = &pdev->dev;
284 
285 	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
286 	dpaux->regs = devm_ioremap_resource(&pdev->dev, regs);
287 	if (IS_ERR(dpaux->regs))
288 		return PTR_ERR(dpaux->regs);
289 
290 	dpaux->irq = platform_get_irq(pdev, 0);
291 	if (dpaux->irq < 0) {
292 		dev_err(&pdev->dev, "failed to get IRQ\n");
293 		return -ENXIO;
294 	}
295 
296 	dpaux->rst = devm_reset_control_get(&pdev->dev, "dpaux");
297 	if (IS_ERR(dpaux->rst)) {
298 		dev_err(&pdev->dev, "failed to get reset control: %ld\n",
299 			PTR_ERR(dpaux->rst));
300 		return PTR_ERR(dpaux->rst);
301 	}
302 
303 	dpaux->clk = devm_clk_get(&pdev->dev, NULL);
304 	if (IS_ERR(dpaux->clk)) {
305 		dev_err(&pdev->dev, "failed to get module clock: %ld\n",
306 			PTR_ERR(dpaux->clk));
307 		return PTR_ERR(dpaux->clk);
308 	}
309 
310 	err = clk_prepare_enable(dpaux->clk);
311 	if (err < 0) {
312 		dev_err(&pdev->dev, "failed to enable module clock: %d\n",
313 			err);
314 		return err;
315 	}
316 
317 	reset_control_deassert(dpaux->rst);
318 
319 	dpaux->clk_parent = devm_clk_get(&pdev->dev, "parent");
320 	if (IS_ERR(dpaux->clk_parent)) {
321 		dev_err(&pdev->dev, "failed to get parent clock: %ld\n",
322 			PTR_ERR(dpaux->clk_parent));
323 		return PTR_ERR(dpaux->clk_parent);
324 	}
325 
326 	err = clk_prepare_enable(dpaux->clk_parent);
327 	if (err < 0) {
328 		dev_err(&pdev->dev, "failed to enable parent clock: %d\n",
329 			err);
330 		return err;
331 	}
332 
333 	err = clk_set_rate(dpaux->clk_parent, 270000000);
334 	if (err < 0) {
335 		dev_err(&pdev->dev, "failed to set clock to 270 MHz: %d\n",
336 			err);
337 		return err;
338 	}
339 
340 	dpaux->vdd = devm_regulator_get(&pdev->dev, "vdd");
341 	if (IS_ERR(dpaux->vdd)) {
342 		dev_err(&pdev->dev, "failed to get VDD supply: %ld\n",
343 			PTR_ERR(dpaux->vdd));
344 		return PTR_ERR(dpaux->vdd);
345 	}
346 
347 	err = devm_request_irq(dpaux->dev, dpaux->irq, tegra_dpaux_irq, 0,
348 			       dev_name(dpaux->dev), dpaux);
349 	if (err < 0) {
350 		dev_err(dpaux->dev, "failed to request IRQ#%u: %d\n",
351 			dpaux->irq, err);
352 		return err;
353 	}
354 
355 	disable_irq(dpaux->irq);
356 
357 	dpaux->aux.transfer = tegra_dpaux_transfer;
358 	dpaux->aux.dev = &pdev->dev;
359 
360 	err = drm_dp_aux_register(&dpaux->aux);
361 	if (err < 0)
362 		return err;
363 
364 	/*
365 	 * Assume that by default the DPAUX/I2C pads will be used for HDMI,
366 	 * so power them up and configure them in I2C mode.
367 	 *
368 	 * The DPAUX code paths reconfigure the pads in AUX mode, but there
369 	 * is no possibility to perform the I2C mode configuration in the
370 	 * HDMI path.
371 	 */
372 	value = tegra_dpaux_readl(dpaux, DPAUX_HYBRID_SPARE);
373 	value &= ~DPAUX_HYBRID_SPARE_PAD_POWER_DOWN;
374 	tegra_dpaux_writel(dpaux, value, DPAUX_HYBRID_SPARE);
375 
376 	value = tegra_dpaux_readl(dpaux, DPAUX_HYBRID_PADCTL);
377 	value = DPAUX_HYBRID_PADCTL_I2C_SDA_INPUT_RCV |
378 		DPAUX_HYBRID_PADCTL_I2C_SCL_INPUT_RCV |
379 		DPAUX_HYBRID_PADCTL_MODE_I2C;
380 	tegra_dpaux_writel(dpaux, value, DPAUX_HYBRID_PADCTL);
381 
382 	/* enable and clear all interrupts */
383 	value = DPAUX_INTR_AUX_DONE | DPAUX_INTR_IRQ_EVENT |
384 		DPAUX_INTR_UNPLUG_EVENT | DPAUX_INTR_PLUG_EVENT;
385 	tegra_dpaux_writel(dpaux, value, DPAUX_INTR_EN_AUX);
386 	tegra_dpaux_writel(dpaux, value, DPAUX_INTR_AUX);
387 
388 	mutex_lock(&dpaux_lock);
389 	list_add_tail(&dpaux->list, &dpaux_list);
390 	mutex_unlock(&dpaux_lock);
391 
392 	platform_set_drvdata(pdev, dpaux);
393 
394 	return 0;
395 }
396 
397 static int tegra_dpaux_remove(struct platform_device *pdev)
398 {
399 	struct tegra_dpaux *dpaux = platform_get_drvdata(pdev);
400 	u32 value;
401 
402 	/* make sure pads are powered down when not in use */
403 	value = tegra_dpaux_readl(dpaux, DPAUX_HYBRID_SPARE);
404 	value |= DPAUX_HYBRID_SPARE_PAD_POWER_DOWN;
405 	tegra_dpaux_writel(dpaux, value, DPAUX_HYBRID_SPARE);
406 
407 	drm_dp_aux_unregister(&dpaux->aux);
408 
409 	mutex_lock(&dpaux_lock);
410 	list_del(&dpaux->list);
411 	mutex_unlock(&dpaux_lock);
412 
413 	cancel_work_sync(&dpaux->work);
414 
415 	clk_disable_unprepare(dpaux->clk_parent);
416 	reset_control_assert(dpaux->rst);
417 	clk_disable_unprepare(dpaux->clk);
418 
419 	return 0;
420 }
421 
422 static const struct of_device_id tegra_dpaux_of_match[] = {
423 	{ .compatible = "nvidia,tegra210-dpaux", },
424 	{ .compatible = "nvidia,tegra124-dpaux", },
425 	{ },
426 };
427 MODULE_DEVICE_TABLE(of, tegra_dpaux_of_match);
428 
429 struct platform_driver tegra_dpaux_driver = {
430 	.driver = {
431 		.name = "tegra-dpaux",
432 		.of_match_table = tegra_dpaux_of_match,
433 	},
434 	.probe = tegra_dpaux_probe,
435 	.remove = tegra_dpaux_remove,
436 };
437 
438 struct tegra_dpaux *tegra_dpaux_find_by_of_node(struct device_node *np)
439 {
440 	struct tegra_dpaux *dpaux;
441 
442 	mutex_lock(&dpaux_lock);
443 
444 	list_for_each_entry(dpaux, &dpaux_list, list)
445 		if (np == dpaux->dev->of_node) {
446 			mutex_unlock(&dpaux_lock);
447 			return dpaux;
448 		}
449 
450 	mutex_unlock(&dpaux_lock);
451 
452 	return NULL;
453 }
454 
455 int tegra_dpaux_attach(struct tegra_dpaux *dpaux, struct tegra_output *output)
456 {
457 	unsigned long timeout;
458 	int err;
459 
460 	output->connector.polled = DRM_CONNECTOR_POLL_HPD;
461 	dpaux->output = output;
462 
463 	err = regulator_enable(dpaux->vdd);
464 	if (err < 0)
465 		return err;
466 
467 	timeout = jiffies + msecs_to_jiffies(250);
468 
469 	while (time_before(jiffies, timeout)) {
470 		enum drm_connector_status status;
471 
472 		status = tegra_dpaux_detect(dpaux);
473 		if (status == connector_status_connected) {
474 			enable_irq(dpaux->irq);
475 			return 0;
476 		}
477 
478 		usleep_range(1000, 2000);
479 	}
480 
481 	return -ETIMEDOUT;
482 }
483 
484 int tegra_dpaux_detach(struct tegra_dpaux *dpaux)
485 {
486 	unsigned long timeout;
487 	int err;
488 
489 	disable_irq(dpaux->irq);
490 
491 	err = regulator_disable(dpaux->vdd);
492 	if (err < 0)
493 		return err;
494 
495 	timeout = jiffies + msecs_to_jiffies(250);
496 
497 	while (time_before(jiffies, timeout)) {
498 		enum drm_connector_status status;
499 
500 		status = tegra_dpaux_detect(dpaux);
501 		if (status == connector_status_disconnected) {
502 			dpaux->output = NULL;
503 			return 0;
504 		}
505 
506 		usleep_range(1000, 2000);
507 	}
508 
509 	return -ETIMEDOUT;
510 }
511 
512 enum drm_connector_status tegra_dpaux_detect(struct tegra_dpaux *dpaux)
513 {
514 	u32 value;
515 
516 	value = tegra_dpaux_readl(dpaux, DPAUX_DP_AUXSTAT);
517 
518 	if (value & DPAUX_DP_AUXSTAT_HPD_STATUS)
519 		return connector_status_connected;
520 
521 	return connector_status_disconnected;
522 }
523 
524 int tegra_dpaux_enable(struct tegra_dpaux *dpaux)
525 {
526 	u32 value;
527 
528 	value = DPAUX_HYBRID_PADCTL_AUX_CMH(2) |
529 		DPAUX_HYBRID_PADCTL_AUX_DRVZ(4) |
530 		DPAUX_HYBRID_PADCTL_AUX_DRVI(0x18) |
531 		DPAUX_HYBRID_PADCTL_AUX_INPUT_RCV |
532 		DPAUX_HYBRID_PADCTL_MODE_AUX;
533 	tegra_dpaux_writel(dpaux, value, DPAUX_HYBRID_PADCTL);
534 
535 	value = tegra_dpaux_readl(dpaux, DPAUX_HYBRID_SPARE);
536 	value &= ~DPAUX_HYBRID_SPARE_PAD_POWER_DOWN;
537 	tegra_dpaux_writel(dpaux, value, DPAUX_HYBRID_SPARE);
538 
539 	return 0;
540 }
541 
542 int tegra_dpaux_disable(struct tegra_dpaux *dpaux)
543 {
544 	u32 value;
545 
546 	value = tegra_dpaux_readl(dpaux, DPAUX_HYBRID_SPARE);
547 	value |= DPAUX_HYBRID_SPARE_PAD_POWER_DOWN;
548 	tegra_dpaux_writel(dpaux, value, DPAUX_HYBRID_SPARE);
549 
550 	return 0;
551 }
552 
553 int tegra_dpaux_prepare(struct tegra_dpaux *dpaux, u8 encoding)
554 {
555 	int err;
556 
557 	err = drm_dp_dpcd_writeb(&dpaux->aux, DP_MAIN_LINK_CHANNEL_CODING_SET,
558 				 encoding);
559 	if (err < 0)
560 		return err;
561 
562 	return 0;
563 }
564 
565 int tegra_dpaux_train(struct tegra_dpaux *dpaux, struct drm_dp_link *link,
566 		      u8 pattern)
567 {
568 	u8 tp = pattern & DP_TRAINING_PATTERN_MASK;
569 	u8 status[DP_LINK_STATUS_SIZE], values[4];
570 	unsigned int i;
571 	int err;
572 
573 	err = drm_dp_dpcd_writeb(&dpaux->aux, DP_TRAINING_PATTERN_SET, pattern);
574 	if (err < 0)
575 		return err;
576 
577 	if (tp == DP_TRAINING_PATTERN_DISABLE)
578 		return 0;
579 
580 	for (i = 0; i < link->num_lanes; i++)
581 		values[i] = DP_TRAIN_MAX_PRE_EMPHASIS_REACHED |
582 			    DP_TRAIN_PRE_EMPH_LEVEL_0 |
583 			    DP_TRAIN_MAX_SWING_REACHED |
584 			    DP_TRAIN_VOLTAGE_SWING_LEVEL_0;
585 
586 	err = drm_dp_dpcd_write(&dpaux->aux, DP_TRAINING_LANE0_SET, values,
587 				link->num_lanes);
588 	if (err < 0)
589 		return err;
590 
591 	usleep_range(500, 1000);
592 
593 	err = drm_dp_dpcd_read_link_status(&dpaux->aux, status);
594 	if (err < 0)
595 		return err;
596 
597 	switch (tp) {
598 	case DP_TRAINING_PATTERN_1:
599 		if (!drm_dp_clock_recovery_ok(status, link->num_lanes))
600 			return -EAGAIN;
601 
602 		break;
603 
604 	case DP_TRAINING_PATTERN_2:
605 		if (!drm_dp_channel_eq_ok(status, link->num_lanes))
606 			return -EAGAIN;
607 
608 		break;
609 
610 	default:
611 		dev_err(dpaux->dev, "unsupported training pattern %u\n", tp);
612 		return -EINVAL;
613 	}
614 
615 	err = drm_dp_dpcd_writeb(&dpaux->aux, DP_EDP_CONFIGURATION_SET, 0);
616 	if (err < 0)
617 		return err;
618 
619 	return 0;
620 }
621