1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (c) 2018, The Linux Foundation. All rights reserved.
4  * datasheet: https://www.ti.com/lit/ds/symlink/sn65dsi86.pdf
5  */
6 
7 #include <linux/auxiliary_bus.h>
8 #include <linux/bits.h>
9 #include <linux/clk.h>
10 #include <linux/debugfs.h>
11 #include <linux/gpio/consumer.h>
12 #include <linux/gpio/driver.h>
13 #include <linux/i2c.h>
14 #include <linux/iopoll.h>
15 #include <linux/module.h>
16 #include <linux/of_graph.h>
17 #include <linux/pm_runtime.h>
18 #include <linux/regmap.h>
19 #include <linux/regulator/consumer.h>
20 
21 #include <asm/unaligned.h>
22 
23 #include <drm/drm_atomic.h>
24 #include <drm/drm_atomic_helper.h>
25 #include <drm/drm_bridge.h>
26 #include <drm/drm_dp_aux_bus.h>
27 #include <drm/drm_dp_helper.h>
28 #include <drm/drm_mipi_dsi.h>
29 #include <drm/drm_of.h>
30 #include <drm/drm_panel.h>
31 #include <drm/drm_print.h>
32 #include <drm/drm_probe_helper.h>
33 
34 #define SN_DEVICE_REV_REG			0x08
35 #define SN_DPPLL_SRC_REG			0x0A
36 #define  DPPLL_CLK_SRC_DSICLK			BIT(0)
37 #define  REFCLK_FREQ_MASK			GENMASK(3, 1)
38 #define  REFCLK_FREQ(x)				((x) << 1)
39 #define  DPPLL_SRC_DP_PLL_LOCK			BIT(7)
40 #define SN_PLL_ENABLE_REG			0x0D
41 #define SN_DSI_LANES_REG			0x10
42 #define  CHA_DSI_LANES_MASK			GENMASK(4, 3)
43 #define  CHA_DSI_LANES(x)			((x) << 3)
44 #define SN_DSIA_CLK_FREQ_REG			0x12
45 #define SN_CHA_ACTIVE_LINE_LENGTH_LOW_REG	0x20
46 #define SN_CHA_VERTICAL_DISPLAY_SIZE_LOW_REG	0x24
47 #define SN_CHA_HSYNC_PULSE_WIDTH_LOW_REG	0x2C
48 #define SN_CHA_HSYNC_PULSE_WIDTH_HIGH_REG	0x2D
49 #define  CHA_HSYNC_POLARITY			BIT(7)
50 #define SN_CHA_VSYNC_PULSE_WIDTH_LOW_REG	0x30
51 #define SN_CHA_VSYNC_PULSE_WIDTH_HIGH_REG	0x31
52 #define  CHA_VSYNC_POLARITY			BIT(7)
53 #define SN_CHA_HORIZONTAL_BACK_PORCH_REG	0x34
54 #define SN_CHA_VERTICAL_BACK_PORCH_REG		0x36
55 #define SN_CHA_HORIZONTAL_FRONT_PORCH_REG	0x38
56 #define SN_CHA_VERTICAL_FRONT_PORCH_REG		0x3A
57 #define SN_LN_ASSIGN_REG			0x59
58 #define  LN_ASSIGN_WIDTH			2
59 #define SN_ENH_FRAME_REG			0x5A
60 #define  VSTREAM_ENABLE				BIT(3)
61 #define  LN_POLRS_OFFSET			4
62 #define  LN_POLRS_MASK				0xf0
63 #define SN_DATA_FORMAT_REG			0x5B
64 #define  BPP_18_RGB				BIT(0)
65 #define SN_HPD_DISABLE_REG			0x5C
66 #define  HPD_DISABLE				BIT(0)
67 #define SN_GPIO_IO_REG				0x5E
68 #define  SN_GPIO_INPUT_SHIFT			4
69 #define  SN_GPIO_OUTPUT_SHIFT			0
70 #define SN_GPIO_CTRL_REG			0x5F
71 #define  SN_GPIO_MUX_INPUT			0
72 #define  SN_GPIO_MUX_OUTPUT			1
73 #define  SN_GPIO_MUX_SPECIAL			2
74 #define  SN_GPIO_MUX_MASK			0x3
75 #define SN_AUX_WDATA_REG(x)			(0x64 + (x))
76 #define SN_AUX_ADDR_19_16_REG			0x74
77 #define SN_AUX_ADDR_15_8_REG			0x75
78 #define SN_AUX_ADDR_7_0_REG			0x76
79 #define SN_AUX_ADDR_MASK			GENMASK(19, 0)
80 #define SN_AUX_LENGTH_REG			0x77
81 #define SN_AUX_CMD_REG				0x78
82 #define  AUX_CMD_SEND				BIT(0)
83 #define  AUX_CMD_REQ(x)				((x) << 4)
84 #define SN_AUX_RDATA_REG(x)			(0x79 + (x))
85 #define SN_SSC_CONFIG_REG			0x93
86 #define  DP_NUM_LANES_MASK			GENMASK(5, 4)
87 #define  DP_NUM_LANES(x)			((x) << 4)
88 #define SN_DATARATE_CONFIG_REG			0x94
89 #define  DP_DATARATE_MASK			GENMASK(7, 5)
90 #define  DP_DATARATE(x)				((x) << 5)
91 #define SN_ML_TX_MODE_REG			0x96
92 #define  ML_TX_MAIN_LINK_OFF			0
93 #define  ML_TX_NORMAL_MODE			BIT(0)
94 #define SN_AUX_CMD_STATUS_REG			0xF4
95 #define  AUX_IRQ_STATUS_AUX_RPLY_TOUT		BIT(3)
96 #define  AUX_IRQ_STATUS_AUX_SHORT		BIT(5)
97 #define  AUX_IRQ_STATUS_NAT_I2C_FAIL		BIT(6)
98 
99 #define MIN_DSI_CLK_FREQ_MHZ	40
100 
101 /* fudge factor required to account for 8b/10b encoding */
102 #define DP_CLK_FUDGE_NUM	10
103 #define DP_CLK_FUDGE_DEN	8
104 
105 /* Matches DP_AUX_MAX_PAYLOAD_BYTES (for now) */
106 #define SN_AUX_MAX_PAYLOAD_BYTES	16
107 
108 #define SN_REGULATOR_SUPPLY_NUM		4
109 
110 #define SN_MAX_DP_LANES			4
111 #define SN_NUM_GPIOS			4
112 #define SN_GPIO_PHYSICAL_OFFSET		1
113 
114 #define SN_LINK_TRAINING_TRIES		10
115 
116 /**
117  * struct ti_sn65dsi86 - Platform data for ti-sn65dsi86 driver.
118  * @bridge_aux:   AUX-bus sub device for MIPI-to-eDP bridge functionality.
119  * @gpio_aux:     AUX-bus sub device for GPIO controller functionality.
120  * @aux_aux:      AUX-bus sub device for eDP AUX channel functionality.
121  *
122  * @dev:          Pointer to the top level (i2c) device.
123  * @regmap:       Regmap for accessing i2c.
124  * @aux:          Our aux channel.
125  * @bridge:       Our bridge.
126  * @connector:    Our connector.
127  * @host_node:    Remote DSI node.
128  * @dsi:          Our MIPI DSI source.
129  * @refclk:       Our reference clock.
130  * @next_bridge:  The bridge on the eDP side.
131  * @enable_gpio:  The GPIO we toggle to enable the bridge.
132  * @supplies:     Data for bulk enabling/disabling our regulators.
133  * @dp_lanes:     Count of dp_lanes we're using.
134  * @ln_assign:    Value to program to the LN_ASSIGN register.
135  * @ln_polrs:     Value for the 4-bit LN_POLRS field of SN_ENH_FRAME_REG.
136  * @comms_enabled: If true then communication over the aux channel is enabled.
137  * @comms_mutex:   Protects modification of comms_enabled.
138  *
139  * @gchip:        If we expose our GPIOs, this is used.
140  * @gchip_output: A cache of whether we've set GPIOs to output.  This
141  *                serves double-duty of keeping track of the direction and
142  *                also keeping track of whether we've incremented the
143  *                pm_runtime reference count for this pin, which we do
144  *                whenever a pin is configured as an output.  This is a
145  *                bitmap so we can do atomic ops on it without an extra
146  *                lock so concurrent users of our 4 GPIOs don't stomp on
147  *                each other's read-modify-write.
148  */
149 struct ti_sn65dsi86 {
150 	struct auxiliary_device		bridge_aux;
151 	struct auxiliary_device		gpio_aux;
152 	struct auxiliary_device		aux_aux;
153 
154 	struct device			*dev;
155 	struct regmap			*regmap;
156 	struct drm_dp_aux		aux;
157 	struct drm_bridge		bridge;
158 	struct drm_connector		connector;
159 	struct device_node		*host_node;
160 	struct mipi_dsi_device		*dsi;
161 	struct clk			*refclk;
162 	struct drm_bridge		*next_bridge;
163 	struct gpio_desc		*enable_gpio;
164 	struct regulator_bulk_data	supplies[SN_REGULATOR_SUPPLY_NUM];
165 	int				dp_lanes;
166 	u8				ln_assign;
167 	u8				ln_polrs;
168 	bool				comms_enabled;
169 	struct mutex			comms_mutex;
170 
171 #if defined(CONFIG_OF_GPIO)
172 	struct gpio_chip		gchip;
173 	DECLARE_BITMAP(gchip_output, SN_NUM_GPIOS);
174 #endif
175 };
176 
177 static const struct regmap_range ti_sn65dsi86_volatile_ranges[] = {
178 	{ .range_min = 0, .range_max = 0xFF },
179 };
180 
181 static const struct regmap_access_table ti_sn_bridge_volatile_table = {
182 	.yes_ranges = ti_sn65dsi86_volatile_ranges,
183 	.n_yes_ranges = ARRAY_SIZE(ti_sn65dsi86_volatile_ranges),
184 };
185 
186 static const struct regmap_config ti_sn65dsi86_regmap_config = {
187 	.reg_bits = 8,
188 	.val_bits = 8,
189 	.volatile_table = &ti_sn_bridge_volatile_table,
190 	.cache_type = REGCACHE_NONE,
191 };
192 
193 static void ti_sn65dsi86_write_u16(struct ti_sn65dsi86 *pdata,
194 				   unsigned int reg, u16 val)
195 {
196 	regmap_write(pdata->regmap, reg, val & 0xFF);
197 	regmap_write(pdata->regmap, reg + 1, val >> 8);
198 }
199 
200 static u32 ti_sn_bridge_get_dsi_freq(struct ti_sn65dsi86 *pdata)
201 {
202 	u32 bit_rate_khz, clk_freq_khz;
203 	struct drm_display_mode *mode =
204 		&pdata->bridge.encoder->crtc->state->adjusted_mode;
205 
206 	bit_rate_khz = mode->clock *
207 			mipi_dsi_pixel_format_to_bpp(pdata->dsi->format);
208 	clk_freq_khz = bit_rate_khz / (pdata->dsi->lanes * 2);
209 
210 	return clk_freq_khz;
211 }
212 
213 /* clk frequencies supported by bridge in Hz in case derived from REFCLK pin */
214 static const u32 ti_sn_bridge_refclk_lut[] = {
215 	12000000,
216 	19200000,
217 	26000000,
218 	27000000,
219 	38400000,
220 };
221 
222 /* clk frequencies supported by bridge in Hz in case derived from DACP/N pin */
223 static const u32 ti_sn_bridge_dsiclk_lut[] = {
224 	468000000,
225 	384000000,
226 	416000000,
227 	486000000,
228 	460800000,
229 };
230 
231 static void ti_sn_bridge_set_refclk_freq(struct ti_sn65dsi86 *pdata)
232 {
233 	int i;
234 	u32 refclk_rate;
235 	const u32 *refclk_lut;
236 	size_t refclk_lut_size;
237 
238 	if (pdata->refclk) {
239 		refclk_rate = clk_get_rate(pdata->refclk);
240 		refclk_lut = ti_sn_bridge_refclk_lut;
241 		refclk_lut_size = ARRAY_SIZE(ti_sn_bridge_refclk_lut);
242 		clk_prepare_enable(pdata->refclk);
243 	} else {
244 		refclk_rate = ti_sn_bridge_get_dsi_freq(pdata) * 1000;
245 		refclk_lut = ti_sn_bridge_dsiclk_lut;
246 		refclk_lut_size = ARRAY_SIZE(ti_sn_bridge_dsiclk_lut);
247 	}
248 
249 	/* for i equals to refclk_lut_size means default frequency */
250 	for (i = 0; i < refclk_lut_size; i++)
251 		if (refclk_lut[i] == refclk_rate)
252 			break;
253 
254 	regmap_update_bits(pdata->regmap, SN_DPPLL_SRC_REG, REFCLK_FREQ_MASK,
255 			   REFCLK_FREQ(i));
256 }
257 
258 static void ti_sn65dsi86_enable_comms(struct ti_sn65dsi86 *pdata)
259 {
260 	mutex_lock(&pdata->comms_mutex);
261 
262 	/* configure bridge ref_clk */
263 	ti_sn_bridge_set_refclk_freq(pdata);
264 
265 	/*
266 	 * HPD on this bridge chip is a bit useless.  This is an eDP bridge
267 	 * so the HPD is an internal signal that's only there to signal that
268 	 * the panel is done powering up.  ...but the bridge chip debounces
269 	 * this signal by between 100 ms and 400 ms (depending on process,
270 	 * voltage, and temperate--I measured it at about 200 ms).  One
271 	 * particular panel asserted HPD 84 ms after it was powered on meaning
272 	 * that we saw HPD 284 ms after power on.  ...but the same panel said
273 	 * that instead of looking at HPD you could just hardcode a delay of
274 	 * 200 ms.  We'll assume that the panel driver will have the hardcoded
275 	 * delay in its prepare and always disable HPD.
276 	 *
277 	 * If HPD somehow makes sense on some future panel we'll have to
278 	 * change this to be conditional on someone specifying that HPD should
279 	 * be used.
280 	 */
281 	regmap_update_bits(pdata->regmap, SN_HPD_DISABLE_REG, HPD_DISABLE,
282 			   HPD_DISABLE);
283 
284 	pdata->comms_enabled = true;
285 
286 	mutex_unlock(&pdata->comms_mutex);
287 }
288 
289 static void ti_sn65dsi86_disable_comms(struct ti_sn65dsi86 *pdata)
290 {
291 	mutex_lock(&pdata->comms_mutex);
292 
293 	pdata->comms_enabled = false;
294 	clk_disable_unprepare(pdata->refclk);
295 
296 	mutex_unlock(&pdata->comms_mutex);
297 }
298 
299 static int __maybe_unused ti_sn65dsi86_resume(struct device *dev)
300 {
301 	struct ti_sn65dsi86 *pdata = dev_get_drvdata(dev);
302 	int ret;
303 
304 	ret = regulator_bulk_enable(SN_REGULATOR_SUPPLY_NUM, pdata->supplies);
305 	if (ret) {
306 		DRM_ERROR("failed to enable supplies %d\n", ret);
307 		return ret;
308 	}
309 
310 	/* td2: min 100 us after regulators before enabling the GPIO */
311 	usleep_range(100, 110);
312 
313 	gpiod_set_value(pdata->enable_gpio, 1);
314 
315 	/*
316 	 * If we have a reference clock we can enable communication w/ the
317 	 * panel (including the aux channel) w/out any need for an input clock
318 	 * so we can do it in resume which lets us read the EDID before
319 	 * pre_enable(). Without a reference clock we need the MIPI reference
320 	 * clock so reading early doesn't work.
321 	 */
322 	if (pdata->refclk)
323 		ti_sn65dsi86_enable_comms(pdata);
324 
325 	return ret;
326 }
327 
328 static int __maybe_unused ti_sn65dsi86_suspend(struct device *dev)
329 {
330 	struct ti_sn65dsi86 *pdata = dev_get_drvdata(dev);
331 	int ret;
332 
333 	if (pdata->refclk)
334 		ti_sn65dsi86_disable_comms(pdata);
335 
336 	gpiod_set_value(pdata->enable_gpio, 0);
337 
338 	ret = regulator_bulk_disable(SN_REGULATOR_SUPPLY_NUM, pdata->supplies);
339 	if (ret)
340 		DRM_ERROR("failed to disable supplies %d\n", ret);
341 
342 	return ret;
343 }
344 
345 static const struct dev_pm_ops ti_sn65dsi86_pm_ops = {
346 	SET_RUNTIME_PM_OPS(ti_sn65dsi86_suspend, ti_sn65dsi86_resume, NULL)
347 	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
348 				pm_runtime_force_resume)
349 };
350 
351 static int status_show(struct seq_file *s, void *data)
352 {
353 	struct ti_sn65dsi86 *pdata = s->private;
354 	unsigned int reg, val;
355 
356 	seq_puts(s, "STATUS REGISTERS:\n");
357 
358 	pm_runtime_get_sync(pdata->dev);
359 
360 	/* IRQ Status Registers, see Table 31 in datasheet */
361 	for (reg = 0xf0; reg <= 0xf8; reg++) {
362 		regmap_read(pdata->regmap, reg, &val);
363 		seq_printf(s, "[0x%02x] = 0x%08x\n", reg, val);
364 	}
365 
366 	pm_runtime_put_autosuspend(pdata->dev);
367 
368 	return 0;
369 }
370 
371 DEFINE_SHOW_ATTRIBUTE(status);
372 
373 static void ti_sn65dsi86_debugfs_remove(void *data)
374 {
375 	debugfs_remove_recursive(data);
376 }
377 
378 static void ti_sn65dsi86_debugfs_init(struct ti_sn65dsi86 *pdata)
379 {
380 	struct device *dev = pdata->dev;
381 	struct dentry *debugfs;
382 	int ret;
383 
384 	debugfs = debugfs_create_dir(dev_name(dev), NULL);
385 
386 	/*
387 	 * We might get an error back if debugfs wasn't enabled in the kernel
388 	 * so let's just silently return upon failure.
389 	 */
390 	if (IS_ERR_OR_NULL(debugfs))
391 		return;
392 
393 	ret = devm_add_action_or_reset(dev, ti_sn65dsi86_debugfs_remove, debugfs);
394 	if (ret)
395 		return;
396 
397 	debugfs_create_file("status", 0600, debugfs, pdata, &status_fops);
398 }
399 
400 /* -----------------------------------------------------------------------------
401  * Auxiliary Devices (*not* AUX)
402  */
403 
404 static void ti_sn65dsi86_uninit_aux(void *data)
405 {
406 	auxiliary_device_uninit(data);
407 }
408 
409 static void ti_sn65dsi86_delete_aux(void *data)
410 {
411 	auxiliary_device_delete(data);
412 }
413 
414 /*
415  * AUX bus docs say that a non-NULL release is mandatory, but it makes no
416  * sense for the model used here where all of the aux devices are allocated
417  * in the single shared structure. We'll use this noop as a workaround.
418  */
419 static void ti_sn65dsi86_noop(struct device *dev) {}
420 
421 static int ti_sn65dsi86_add_aux_device(struct ti_sn65dsi86 *pdata,
422 				       struct auxiliary_device *aux,
423 				       const char *name)
424 {
425 	struct device *dev = pdata->dev;
426 	int ret;
427 
428 	aux->name = name;
429 	aux->dev.parent = dev;
430 	aux->dev.release = ti_sn65dsi86_noop;
431 	device_set_of_node_from_dev(&aux->dev, dev);
432 	ret = auxiliary_device_init(aux);
433 	if (ret)
434 		return ret;
435 	ret = devm_add_action_or_reset(dev, ti_sn65dsi86_uninit_aux, aux);
436 	if (ret)
437 		return ret;
438 
439 	ret = auxiliary_device_add(aux);
440 	if (ret)
441 		return ret;
442 	ret = devm_add_action_or_reset(dev, ti_sn65dsi86_delete_aux, aux);
443 
444 	return ret;
445 }
446 
447 /* -----------------------------------------------------------------------------
448  * AUX Adapter
449  */
450 
451 static struct ti_sn65dsi86 *aux_to_ti_sn65dsi86(struct drm_dp_aux *aux)
452 {
453 	return container_of(aux, struct ti_sn65dsi86, aux);
454 }
455 
456 static ssize_t ti_sn_aux_transfer(struct drm_dp_aux *aux,
457 				  struct drm_dp_aux_msg *msg)
458 {
459 	struct ti_sn65dsi86 *pdata = aux_to_ti_sn65dsi86(aux);
460 	u32 request = msg->request & ~(DP_AUX_I2C_MOT | DP_AUX_I2C_WRITE_STATUS_UPDATE);
461 	u32 request_val = AUX_CMD_REQ(msg->request);
462 	u8 *buf = msg->buffer;
463 	unsigned int len = msg->size;
464 	unsigned int val;
465 	int ret;
466 	u8 addr_len[SN_AUX_LENGTH_REG + 1 - SN_AUX_ADDR_19_16_REG];
467 
468 	if (len > SN_AUX_MAX_PAYLOAD_BYTES)
469 		return -EINVAL;
470 
471 	pm_runtime_get_sync(pdata->dev);
472 	mutex_lock(&pdata->comms_mutex);
473 
474 	/*
475 	 * If someone tries to do a DDC over AUX transaction before pre_enable()
476 	 * on a device without a dedicated reference clock then we just can't
477 	 * do it. Fail right away. This prevents non-refclk users from reading
478 	 * the EDID before enabling the panel but such is life.
479 	 */
480 	if (!pdata->comms_enabled) {
481 		ret = -EIO;
482 		goto exit;
483 	}
484 
485 	switch (request) {
486 	case DP_AUX_NATIVE_WRITE:
487 	case DP_AUX_I2C_WRITE:
488 	case DP_AUX_NATIVE_READ:
489 	case DP_AUX_I2C_READ:
490 		regmap_write(pdata->regmap, SN_AUX_CMD_REG, request_val);
491 		/* Assume it's good */
492 		msg->reply = 0;
493 		break;
494 	default:
495 		ret = -EINVAL;
496 		goto exit;
497 	}
498 
499 	BUILD_BUG_ON(sizeof(addr_len) != sizeof(__be32));
500 	put_unaligned_be32((msg->address & SN_AUX_ADDR_MASK) << 8 | len,
501 			   addr_len);
502 	regmap_bulk_write(pdata->regmap, SN_AUX_ADDR_19_16_REG, addr_len,
503 			  ARRAY_SIZE(addr_len));
504 
505 	if (request == DP_AUX_NATIVE_WRITE || request == DP_AUX_I2C_WRITE)
506 		regmap_bulk_write(pdata->regmap, SN_AUX_WDATA_REG(0), buf, len);
507 
508 	/* Clear old status bits before start so we don't get confused */
509 	regmap_write(pdata->regmap, SN_AUX_CMD_STATUS_REG,
510 		     AUX_IRQ_STATUS_NAT_I2C_FAIL |
511 		     AUX_IRQ_STATUS_AUX_RPLY_TOUT |
512 		     AUX_IRQ_STATUS_AUX_SHORT);
513 
514 	regmap_write(pdata->regmap, SN_AUX_CMD_REG, request_val | AUX_CMD_SEND);
515 
516 	/* Zero delay loop because i2c transactions are slow already */
517 	ret = regmap_read_poll_timeout(pdata->regmap, SN_AUX_CMD_REG, val,
518 				       !(val & AUX_CMD_SEND), 0, 50 * 1000);
519 	if (ret)
520 		goto exit;
521 
522 	ret = regmap_read(pdata->regmap, SN_AUX_CMD_STATUS_REG, &val);
523 	if (ret)
524 		goto exit;
525 
526 	if (val & AUX_IRQ_STATUS_AUX_RPLY_TOUT) {
527 		/*
528 		 * The hardware tried the message seven times per the DP spec
529 		 * but it hit a timeout. We ignore defers here because they're
530 		 * handled in hardware.
531 		 */
532 		ret = -ETIMEDOUT;
533 		goto exit;
534 	}
535 
536 	if (val & AUX_IRQ_STATUS_AUX_SHORT) {
537 		ret = regmap_read(pdata->regmap, SN_AUX_LENGTH_REG, &len);
538 		if (ret)
539 			goto exit;
540 	} else if (val & AUX_IRQ_STATUS_NAT_I2C_FAIL) {
541 		switch (request) {
542 		case DP_AUX_I2C_WRITE:
543 		case DP_AUX_I2C_READ:
544 			msg->reply |= DP_AUX_I2C_REPLY_NACK;
545 			break;
546 		case DP_AUX_NATIVE_READ:
547 		case DP_AUX_NATIVE_WRITE:
548 			msg->reply |= DP_AUX_NATIVE_REPLY_NACK;
549 			break;
550 		}
551 		len = 0;
552 		goto exit;
553 	}
554 
555 	if (request != DP_AUX_NATIVE_WRITE && request != DP_AUX_I2C_WRITE && len != 0)
556 		ret = regmap_bulk_read(pdata->regmap, SN_AUX_RDATA_REG(0), buf, len);
557 
558 exit:
559 	mutex_unlock(&pdata->comms_mutex);
560 	pm_runtime_mark_last_busy(pdata->dev);
561 	pm_runtime_put_autosuspend(pdata->dev);
562 
563 	if (ret)
564 		return ret;
565 	return len;
566 }
567 
568 static int ti_sn_aux_probe(struct auxiliary_device *adev,
569 			   const struct auxiliary_device_id *id)
570 {
571 	struct ti_sn65dsi86 *pdata = dev_get_drvdata(adev->dev.parent);
572 	int ret;
573 
574 	pdata->aux.name = "ti-sn65dsi86-aux";
575 	pdata->aux.dev = &adev->dev;
576 	pdata->aux.transfer = ti_sn_aux_transfer;
577 	drm_dp_aux_init(&pdata->aux);
578 
579 	ret = devm_of_dp_aux_populate_ep_devices(&pdata->aux);
580 	if (ret)
581 		return ret;
582 
583 	/*
584 	 * The eDP to MIPI bridge parts don't work until the AUX channel is
585 	 * setup so we don't add it in the main driver probe, we add it now.
586 	 */
587 	return ti_sn65dsi86_add_aux_device(pdata, &pdata->bridge_aux, "bridge");
588 }
589 
590 static const struct auxiliary_device_id ti_sn_aux_id_table[] = {
591 	{ .name = "ti_sn65dsi86.aux", },
592 	{},
593 };
594 
595 static struct auxiliary_driver ti_sn_aux_driver = {
596 	.name = "aux",
597 	.probe = ti_sn_aux_probe,
598 	.id_table = ti_sn_aux_id_table,
599 };
600 
601 /* -----------------------------------------------------------------------------
602  * DRM Connector Operations
603  */
604 
605 static struct ti_sn65dsi86 *
606 connector_to_ti_sn65dsi86(struct drm_connector *connector)
607 {
608 	return container_of(connector, struct ti_sn65dsi86, connector);
609 }
610 
611 static int ti_sn_bridge_connector_get_modes(struct drm_connector *connector)
612 {
613 	struct ti_sn65dsi86 *pdata = connector_to_ti_sn65dsi86(connector);
614 
615 	return drm_bridge_get_modes(pdata->next_bridge, connector);
616 }
617 
618 static enum drm_mode_status
619 ti_sn_bridge_connector_mode_valid(struct drm_connector *connector,
620 				  struct drm_display_mode *mode)
621 {
622 	/* maximum supported resolution is 4K at 60 fps */
623 	if (mode->clock > 594000)
624 		return MODE_CLOCK_HIGH;
625 
626 	return MODE_OK;
627 }
628 
629 static struct drm_connector_helper_funcs ti_sn_bridge_connector_helper_funcs = {
630 	.get_modes = ti_sn_bridge_connector_get_modes,
631 	.mode_valid = ti_sn_bridge_connector_mode_valid,
632 };
633 
634 static const struct drm_connector_funcs ti_sn_bridge_connector_funcs = {
635 	.fill_modes = drm_helper_probe_single_connector_modes,
636 	.destroy = drm_connector_cleanup,
637 	.reset = drm_atomic_helper_connector_reset,
638 	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
639 	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
640 };
641 
642 static int ti_sn_bridge_connector_init(struct ti_sn65dsi86 *pdata)
643 {
644 	int ret;
645 
646 	ret = drm_connector_init(pdata->bridge.dev, &pdata->connector,
647 				 &ti_sn_bridge_connector_funcs,
648 				 DRM_MODE_CONNECTOR_eDP);
649 	if (ret) {
650 		DRM_ERROR("Failed to initialize connector with drm\n");
651 		return ret;
652 	}
653 
654 	drm_connector_helper_add(&pdata->connector,
655 				 &ti_sn_bridge_connector_helper_funcs);
656 	drm_connector_attach_encoder(&pdata->connector, pdata->bridge.encoder);
657 
658 	return 0;
659 }
660 
661 /*------------------------------------------------------------------------------
662  * DRM Bridge
663  */
664 
665 static struct ti_sn65dsi86 *bridge_to_ti_sn65dsi86(struct drm_bridge *bridge)
666 {
667 	return container_of(bridge, struct ti_sn65dsi86, bridge);
668 }
669 
670 static int ti_sn_bridge_attach(struct drm_bridge *bridge,
671 			       enum drm_bridge_attach_flags flags)
672 {
673 	int ret, val;
674 	struct ti_sn65dsi86 *pdata = bridge_to_ti_sn65dsi86(bridge);
675 	struct mipi_dsi_host *host;
676 	struct mipi_dsi_device *dsi;
677 	const struct mipi_dsi_device_info info = { .type = "ti_sn_bridge",
678 						   .channel = 0,
679 						   .node = NULL,
680 						 };
681 
682 	if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) {
683 		DRM_ERROR("Fix bridge driver to make connector optional!");
684 		return -EINVAL;
685 	}
686 
687 	pdata->aux.drm_dev = bridge->dev;
688 	ret = drm_dp_aux_register(&pdata->aux);
689 	if (ret < 0) {
690 		drm_err(bridge->dev, "Failed to register DP AUX channel: %d\n", ret);
691 		return ret;
692 	}
693 
694 	ret = ti_sn_bridge_connector_init(pdata);
695 	if (ret < 0)
696 		goto err_conn_init;
697 
698 	/*
699 	 * TODO: ideally finding host resource and dsi dev registration needs
700 	 * to be done in bridge probe. But some existing DSI host drivers will
701 	 * wait for any of the drm_bridge/drm_panel to get added to the global
702 	 * bridge/panel list, before completing their probe. So if we do the
703 	 * dsi dev registration part in bridge probe, before populating in
704 	 * the global bridge list, then it will cause deadlock as dsi host probe
705 	 * will never complete, neither our bridge probe. So keeping it here
706 	 * will satisfy most of the existing host drivers. Once the host driver
707 	 * is fixed we can move the below code to bridge probe safely.
708 	 */
709 	host = of_find_mipi_dsi_host_by_node(pdata->host_node);
710 	if (!host) {
711 		DRM_ERROR("failed to find dsi host\n");
712 		ret = -ENODEV;
713 		goto err_dsi_host;
714 	}
715 
716 	dsi = mipi_dsi_device_register_full(host, &info);
717 	if (IS_ERR(dsi)) {
718 		DRM_ERROR("failed to create dsi device\n");
719 		ret = PTR_ERR(dsi);
720 		goto err_dsi_host;
721 	}
722 
723 	/* TODO: setting to 4 MIPI lanes always for now */
724 	dsi->lanes = 4;
725 	dsi->format = MIPI_DSI_FMT_RGB888;
726 	dsi->mode_flags = MIPI_DSI_MODE_VIDEO;
727 
728 	/* check if continuous dsi clock is required or not */
729 	pm_runtime_get_sync(pdata->dev);
730 	regmap_read(pdata->regmap, SN_DPPLL_SRC_REG, &val);
731 	pm_runtime_put_autosuspend(pdata->dev);
732 	if (!(val & DPPLL_CLK_SRC_DSICLK))
733 		dsi->mode_flags |= MIPI_DSI_CLOCK_NON_CONTINUOUS;
734 
735 	ret = mipi_dsi_attach(dsi);
736 	if (ret < 0) {
737 		DRM_ERROR("failed to attach dsi to host\n");
738 		goto err_dsi_attach;
739 	}
740 	pdata->dsi = dsi;
741 
742 	/* We never want the next bridge to *also* create a connector: */
743 	flags |= DRM_BRIDGE_ATTACH_NO_CONNECTOR;
744 
745 	/* Attach the next bridge */
746 	ret = drm_bridge_attach(bridge->encoder, pdata->next_bridge,
747 				&pdata->bridge, flags);
748 	if (ret < 0)
749 		goto err_dsi_detach;
750 
751 	return 0;
752 
753 err_dsi_detach:
754 	mipi_dsi_detach(dsi);
755 err_dsi_attach:
756 	mipi_dsi_device_unregister(dsi);
757 err_dsi_host:
758 	drm_connector_cleanup(&pdata->connector);
759 err_conn_init:
760 	drm_dp_aux_unregister(&pdata->aux);
761 	return ret;
762 }
763 
764 static void ti_sn_bridge_detach(struct drm_bridge *bridge)
765 {
766 	drm_dp_aux_unregister(&bridge_to_ti_sn65dsi86(bridge)->aux);
767 }
768 
769 static void ti_sn_bridge_disable(struct drm_bridge *bridge)
770 {
771 	struct ti_sn65dsi86 *pdata = bridge_to_ti_sn65dsi86(bridge);
772 
773 	/* disable video stream */
774 	regmap_update_bits(pdata->regmap, SN_ENH_FRAME_REG, VSTREAM_ENABLE, 0);
775 }
776 
777 static void ti_sn_bridge_set_dsi_rate(struct ti_sn65dsi86 *pdata)
778 {
779 	unsigned int bit_rate_mhz, clk_freq_mhz;
780 	unsigned int val;
781 	struct drm_display_mode *mode =
782 		&pdata->bridge.encoder->crtc->state->adjusted_mode;
783 
784 	/* set DSIA clk frequency */
785 	bit_rate_mhz = (mode->clock / 1000) *
786 			mipi_dsi_pixel_format_to_bpp(pdata->dsi->format);
787 	clk_freq_mhz = bit_rate_mhz / (pdata->dsi->lanes * 2);
788 
789 	/* for each increment in val, frequency increases by 5MHz */
790 	val = (MIN_DSI_CLK_FREQ_MHZ / 5) +
791 		(((clk_freq_mhz - MIN_DSI_CLK_FREQ_MHZ) / 5) & 0xFF);
792 	regmap_write(pdata->regmap, SN_DSIA_CLK_FREQ_REG, val);
793 }
794 
795 static unsigned int ti_sn_bridge_get_bpp(struct ti_sn65dsi86 *pdata)
796 {
797 	if (pdata->connector.display_info.bpc <= 6)
798 		return 18;
799 	else
800 		return 24;
801 }
802 
803 /*
804  * LUT index corresponds to register value and
805  * LUT values corresponds to dp data rate supported
806  * by the bridge in Mbps unit.
807  */
808 static const unsigned int ti_sn_bridge_dp_rate_lut[] = {
809 	0, 1620, 2160, 2430, 2700, 3240, 4320, 5400
810 };
811 
812 static int ti_sn_bridge_calc_min_dp_rate_idx(struct ti_sn65dsi86 *pdata)
813 {
814 	unsigned int bit_rate_khz, dp_rate_mhz;
815 	unsigned int i;
816 	struct drm_display_mode *mode =
817 		&pdata->bridge.encoder->crtc->state->adjusted_mode;
818 
819 	/* Calculate minimum bit rate based on our pixel clock. */
820 	bit_rate_khz = mode->clock * ti_sn_bridge_get_bpp(pdata);
821 
822 	/* Calculate minimum DP data rate, taking 80% as per DP spec */
823 	dp_rate_mhz = DIV_ROUND_UP(bit_rate_khz * DP_CLK_FUDGE_NUM,
824 				   1000 * pdata->dp_lanes * DP_CLK_FUDGE_DEN);
825 
826 	for (i = 1; i < ARRAY_SIZE(ti_sn_bridge_dp_rate_lut) - 1; i++)
827 		if (ti_sn_bridge_dp_rate_lut[i] >= dp_rate_mhz)
828 			break;
829 
830 	return i;
831 }
832 
833 static unsigned int ti_sn_bridge_read_valid_rates(struct ti_sn65dsi86 *pdata)
834 {
835 	unsigned int valid_rates = 0;
836 	unsigned int rate_per_200khz;
837 	unsigned int rate_mhz;
838 	u8 dpcd_val;
839 	int ret;
840 	int i, j;
841 
842 	ret = drm_dp_dpcd_readb(&pdata->aux, DP_EDP_DPCD_REV, &dpcd_val);
843 	if (ret != 1) {
844 		DRM_DEV_ERROR(pdata->dev,
845 			      "Can't read eDP rev (%d), assuming 1.1\n", ret);
846 		dpcd_val = DP_EDP_11;
847 	}
848 
849 	if (dpcd_val >= DP_EDP_14) {
850 		/* eDP 1.4 devices must provide a custom table */
851 		__le16 sink_rates[DP_MAX_SUPPORTED_RATES];
852 
853 		ret = drm_dp_dpcd_read(&pdata->aux, DP_SUPPORTED_LINK_RATES,
854 				       sink_rates, sizeof(sink_rates));
855 
856 		if (ret != sizeof(sink_rates)) {
857 			DRM_DEV_ERROR(pdata->dev,
858 				"Can't read supported rate table (%d)\n", ret);
859 
860 			/* By zeroing we'll fall back to DP_MAX_LINK_RATE. */
861 			memset(sink_rates, 0, sizeof(sink_rates));
862 		}
863 
864 		for (i = 0; i < ARRAY_SIZE(sink_rates); i++) {
865 			rate_per_200khz = le16_to_cpu(sink_rates[i]);
866 
867 			if (!rate_per_200khz)
868 				break;
869 
870 			rate_mhz = rate_per_200khz * 200 / 1000;
871 			for (j = 0;
872 			     j < ARRAY_SIZE(ti_sn_bridge_dp_rate_lut);
873 			     j++) {
874 				if (ti_sn_bridge_dp_rate_lut[j] == rate_mhz)
875 					valid_rates |= BIT(j);
876 			}
877 		}
878 
879 		for (i = 0; i < ARRAY_SIZE(ti_sn_bridge_dp_rate_lut); i++) {
880 			if (valid_rates & BIT(i))
881 				return valid_rates;
882 		}
883 		DRM_DEV_ERROR(pdata->dev,
884 			      "No matching eDP rates in table; falling back\n");
885 	}
886 
887 	/* On older versions best we can do is use DP_MAX_LINK_RATE */
888 	ret = drm_dp_dpcd_readb(&pdata->aux, DP_MAX_LINK_RATE, &dpcd_val);
889 	if (ret != 1) {
890 		DRM_DEV_ERROR(pdata->dev,
891 			      "Can't read max rate (%d); assuming 5.4 GHz\n",
892 			      ret);
893 		dpcd_val = DP_LINK_BW_5_4;
894 	}
895 
896 	switch (dpcd_val) {
897 	default:
898 		DRM_DEV_ERROR(pdata->dev,
899 			      "Unexpected max rate (%#x); assuming 5.4 GHz\n",
900 			      (int)dpcd_val);
901 		fallthrough;
902 	case DP_LINK_BW_5_4:
903 		valid_rates |= BIT(7);
904 		fallthrough;
905 	case DP_LINK_BW_2_7:
906 		valid_rates |= BIT(4);
907 		fallthrough;
908 	case DP_LINK_BW_1_62:
909 		valid_rates |= BIT(1);
910 		break;
911 	}
912 
913 	return valid_rates;
914 }
915 
916 static void ti_sn_bridge_set_video_timings(struct ti_sn65dsi86 *pdata)
917 {
918 	struct drm_display_mode *mode =
919 		&pdata->bridge.encoder->crtc->state->adjusted_mode;
920 	u8 hsync_polarity = 0, vsync_polarity = 0;
921 
922 	if (mode->flags & DRM_MODE_FLAG_PHSYNC)
923 		hsync_polarity = CHA_HSYNC_POLARITY;
924 	if (mode->flags & DRM_MODE_FLAG_PVSYNC)
925 		vsync_polarity = CHA_VSYNC_POLARITY;
926 
927 	ti_sn65dsi86_write_u16(pdata, SN_CHA_ACTIVE_LINE_LENGTH_LOW_REG,
928 			       mode->hdisplay);
929 	ti_sn65dsi86_write_u16(pdata, SN_CHA_VERTICAL_DISPLAY_SIZE_LOW_REG,
930 			       mode->vdisplay);
931 	regmap_write(pdata->regmap, SN_CHA_HSYNC_PULSE_WIDTH_LOW_REG,
932 		     (mode->hsync_end - mode->hsync_start) & 0xFF);
933 	regmap_write(pdata->regmap, SN_CHA_HSYNC_PULSE_WIDTH_HIGH_REG,
934 		     (((mode->hsync_end - mode->hsync_start) >> 8) & 0x7F) |
935 		     hsync_polarity);
936 	regmap_write(pdata->regmap, SN_CHA_VSYNC_PULSE_WIDTH_LOW_REG,
937 		     (mode->vsync_end - mode->vsync_start) & 0xFF);
938 	regmap_write(pdata->regmap, SN_CHA_VSYNC_PULSE_WIDTH_HIGH_REG,
939 		     (((mode->vsync_end - mode->vsync_start) >> 8) & 0x7F) |
940 		     vsync_polarity);
941 
942 	regmap_write(pdata->regmap, SN_CHA_HORIZONTAL_BACK_PORCH_REG,
943 		     (mode->htotal - mode->hsync_end) & 0xFF);
944 	regmap_write(pdata->regmap, SN_CHA_VERTICAL_BACK_PORCH_REG,
945 		     (mode->vtotal - mode->vsync_end) & 0xFF);
946 
947 	regmap_write(pdata->regmap, SN_CHA_HORIZONTAL_FRONT_PORCH_REG,
948 		     (mode->hsync_start - mode->hdisplay) & 0xFF);
949 	regmap_write(pdata->regmap, SN_CHA_VERTICAL_FRONT_PORCH_REG,
950 		     (mode->vsync_start - mode->vdisplay) & 0xFF);
951 
952 	usleep_range(10000, 10500); /* 10ms delay recommended by spec */
953 }
954 
955 static unsigned int ti_sn_get_max_lanes(struct ti_sn65dsi86 *pdata)
956 {
957 	u8 data;
958 	int ret;
959 
960 	ret = drm_dp_dpcd_readb(&pdata->aux, DP_MAX_LANE_COUNT, &data);
961 	if (ret != 1) {
962 		DRM_DEV_ERROR(pdata->dev,
963 			      "Can't read lane count (%d); assuming 4\n", ret);
964 		return 4;
965 	}
966 
967 	return data & DP_LANE_COUNT_MASK;
968 }
969 
970 static int ti_sn_link_training(struct ti_sn65dsi86 *pdata, int dp_rate_idx,
971 			       const char **last_err_str)
972 {
973 	unsigned int val;
974 	int ret;
975 	int i;
976 
977 	/* set dp clk frequency value */
978 	regmap_update_bits(pdata->regmap, SN_DATARATE_CONFIG_REG,
979 			   DP_DATARATE_MASK, DP_DATARATE(dp_rate_idx));
980 
981 	/* enable DP PLL */
982 	regmap_write(pdata->regmap, SN_PLL_ENABLE_REG, 1);
983 
984 	ret = regmap_read_poll_timeout(pdata->regmap, SN_DPPLL_SRC_REG, val,
985 				       val & DPPLL_SRC_DP_PLL_LOCK, 1000,
986 				       50 * 1000);
987 	if (ret) {
988 		*last_err_str = "DP_PLL_LOCK polling failed";
989 		goto exit;
990 	}
991 
992 	/*
993 	 * We'll try to link train several times.  As part of link training
994 	 * the bridge chip will write DP_SET_POWER_D0 to DP_SET_POWER.  If
995 	 * the panel isn't ready quite it might respond NAK here which means
996 	 * we need to try again.
997 	 */
998 	for (i = 0; i < SN_LINK_TRAINING_TRIES; i++) {
999 		/* Semi auto link training mode */
1000 		regmap_write(pdata->regmap, SN_ML_TX_MODE_REG, 0x0A);
1001 		ret = regmap_read_poll_timeout(pdata->regmap, SN_ML_TX_MODE_REG, val,
1002 					       val == ML_TX_MAIN_LINK_OFF ||
1003 					       val == ML_TX_NORMAL_MODE, 1000,
1004 					       500 * 1000);
1005 		if (ret) {
1006 			*last_err_str = "Training complete polling failed";
1007 		} else if (val == ML_TX_MAIN_LINK_OFF) {
1008 			*last_err_str = "Link training failed, link is off";
1009 			ret = -EIO;
1010 			continue;
1011 		}
1012 
1013 		break;
1014 	}
1015 
1016 	/* If we saw quite a few retries, add a note about it */
1017 	if (!ret && i > SN_LINK_TRAINING_TRIES / 2)
1018 		DRM_DEV_INFO(pdata->dev, "Link training needed %d retries\n", i);
1019 
1020 exit:
1021 	/* Disable the PLL if we failed */
1022 	if (ret)
1023 		regmap_write(pdata->regmap, SN_PLL_ENABLE_REG, 0);
1024 
1025 	return ret;
1026 }
1027 
1028 static void ti_sn_bridge_enable(struct drm_bridge *bridge)
1029 {
1030 	struct ti_sn65dsi86 *pdata = bridge_to_ti_sn65dsi86(bridge);
1031 	const char *last_err_str = "No supported DP rate";
1032 	unsigned int valid_rates;
1033 	int dp_rate_idx;
1034 	unsigned int val;
1035 	int ret = -EINVAL;
1036 	int max_dp_lanes;
1037 
1038 	max_dp_lanes = ti_sn_get_max_lanes(pdata);
1039 	pdata->dp_lanes = min(pdata->dp_lanes, max_dp_lanes);
1040 
1041 	/* DSI_A lane config */
1042 	val = CHA_DSI_LANES(SN_MAX_DP_LANES - pdata->dsi->lanes);
1043 	regmap_update_bits(pdata->regmap, SN_DSI_LANES_REG,
1044 			   CHA_DSI_LANES_MASK, val);
1045 
1046 	regmap_write(pdata->regmap, SN_LN_ASSIGN_REG, pdata->ln_assign);
1047 	regmap_update_bits(pdata->regmap, SN_ENH_FRAME_REG, LN_POLRS_MASK,
1048 			   pdata->ln_polrs << LN_POLRS_OFFSET);
1049 
1050 	/* set dsi clk frequency value */
1051 	ti_sn_bridge_set_dsi_rate(pdata);
1052 
1053 	/*
1054 	 * The SN65DSI86 only supports ASSR Display Authentication method and
1055 	 * this method is enabled by default. An eDP panel must support this
1056 	 * authentication method. We need to enable this method in the eDP panel
1057 	 * at DisplayPort address 0x0010A prior to link training.
1058 	 */
1059 	drm_dp_dpcd_writeb(&pdata->aux, DP_EDP_CONFIGURATION_SET,
1060 			   DP_ALTERNATE_SCRAMBLER_RESET_ENABLE);
1061 
1062 	/* Set the DP output format (18 bpp or 24 bpp) */
1063 	val = (ti_sn_bridge_get_bpp(pdata) == 18) ? BPP_18_RGB : 0;
1064 	regmap_update_bits(pdata->regmap, SN_DATA_FORMAT_REG, BPP_18_RGB, val);
1065 
1066 	/* DP lane config */
1067 	val = DP_NUM_LANES(min(pdata->dp_lanes, 3));
1068 	regmap_update_bits(pdata->regmap, SN_SSC_CONFIG_REG, DP_NUM_LANES_MASK,
1069 			   val);
1070 
1071 	valid_rates = ti_sn_bridge_read_valid_rates(pdata);
1072 
1073 	/* Train until we run out of rates */
1074 	for (dp_rate_idx = ti_sn_bridge_calc_min_dp_rate_idx(pdata);
1075 	     dp_rate_idx < ARRAY_SIZE(ti_sn_bridge_dp_rate_lut);
1076 	     dp_rate_idx++) {
1077 		if (!(valid_rates & BIT(dp_rate_idx)))
1078 			continue;
1079 
1080 		ret = ti_sn_link_training(pdata, dp_rate_idx, &last_err_str);
1081 		if (!ret)
1082 			break;
1083 	}
1084 	if (ret) {
1085 		DRM_DEV_ERROR(pdata->dev, "%s (%d)\n", last_err_str, ret);
1086 		return;
1087 	}
1088 
1089 	/* config video parameters */
1090 	ti_sn_bridge_set_video_timings(pdata);
1091 
1092 	/* enable video stream */
1093 	regmap_update_bits(pdata->regmap, SN_ENH_FRAME_REG, VSTREAM_ENABLE,
1094 			   VSTREAM_ENABLE);
1095 }
1096 
1097 static void ti_sn_bridge_pre_enable(struct drm_bridge *bridge)
1098 {
1099 	struct ti_sn65dsi86 *pdata = bridge_to_ti_sn65dsi86(bridge);
1100 
1101 	pm_runtime_get_sync(pdata->dev);
1102 
1103 	if (!pdata->refclk)
1104 		ti_sn65dsi86_enable_comms(pdata);
1105 
1106 	/* td7: min 100 us after enable before DSI data */
1107 	usleep_range(100, 110);
1108 }
1109 
1110 static void ti_sn_bridge_post_disable(struct drm_bridge *bridge)
1111 {
1112 	struct ti_sn65dsi86 *pdata = bridge_to_ti_sn65dsi86(bridge);
1113 
1114 	/* semi auto link training mode OFF */
1115 	regmap_write(pdata->regmap, SN_ML_TX_MODE_REG, 0);
1116 	/* Num lanes to 0 as per power sequencing in data sheet */
1117 	regmap_update_bits(pdata->regmap, SN_SSC_CONFIG_REG, DP_NUM_LANES_MASK, 0);
1118 	/* disable DP PLL */
1119 	regmap_write(pdata->regmap, SN_PLL_ENABLE_REG, 0);
1120 
1121 	if (!pdata->refclk)
1122 		ti_sn65dsi86_disable_comms(pdata);
1123 
1124 	pm_runtime_put_sync(pdata->dev);
1125 }
1126 
1127 static const struct drm_bridge_funcs ti_sn_bridge_funcs = {
1128 	.attach = ti_sn_bridge_attach,
1129 	.detach = ti_sn_bridge_detach,
1130 	.pre_enable = ti_sn_bridge_pre_enable,
1131 	.enable = ti_sn_bridge_enable,
1132 	.disable = ti_sn_bridge_disable,
1133 	.post_disable = ti_sn_bridge_post_disable,
1134 };
1135 
1136 static void ti_sn_bridge_parse_lanes(struct ti_sn65dsi86 *pdata,
1137 				     struct device_node *np)
1138 {
1139 	u32 lane_assignments[SN_MAX_DP_LANES] = { 0, 1, 2, 3 };
1140 	u32 lane_polarities[SN_MAX_DP_LANES] = { };
1141 	struct device_node *endpoint;
1142 	u8 ln_assign = 0;
1143 	u8 ln_polrs = 0;
1144 	int dp_lanes;
1145 	int i;
1146 
1147 	/*
1148 	 * Read config from the device tree about lane remapping and lane
1149 	 * polarities.  These are optional and we assume identity map and
1150 	 * normal polarity if nothing is specified.  It's OK to specify just
1151 	 * data-lanes but not lane-polarities but not vice versa.
1152 	 *
1153 	 * Error checking is light (we just make sure we don't crash or
1154 	 * buffer overrun) and we assume dts is well formed and specifying
1155 	 * mappings that the hardware supports.
1156 	 */
1157 	endpoint = of_graph_get_endpoint_by_regs(np, 1, -1);
1158 	dp_lanes = of_property_count_u32_elems(endpoint, "data-lanes");
1159 	if (dp_lanes > 0 && dp_lanes <= SN_MAX_DP_LANES) {
1160 		of_property_read_u32_array(endpoint, "data-lanes",
1161 					   lane_assignments, dp_lanes);
1162 		of_property_read_u32_array(endpoint, "lane-polarities",
1163 					   lane_polarities, dp_lanes);
1164 	} else {
1165 		dp_lanes = SN_MAX_DP_LANES;
1166 	}
1167 	of_node_put(endpoint);
1168 
1169 	/*
1170 	 * Convert into register format.  Loop over all lanes even if
1171 	 * data-lanes had fewer elements so that we nicely initialize
1172 	 * the LN_ASSIGN register.
1173 	 */
1174 	for (i = SN_MAX_DP_LANES - 1; i >= 0; i--) {
1175 		ln_assign = ln_assign << LN_ASSIGN_WIDTH | lane_assignments[i];
1176 		ln_polrs = ln_polrs << 1 | lane_polarities[i];
1177 	}
1178 
1179 	/* Stash in our struct for when we power on */
1180 	pdata->dp_lanes = dp_lanes;
1181 	pdata->ln_assign = ln_assign;
1182 	pdata->ln_polrs = ln_polrs;
1183 }
1184 
1185 static int ti_sn_bridge_parse_dsi_host(struct ti_sn65dsi86 *pdata)
1186 {
1187 	struct device_node *np = pdata->dev->of_node;
1188 
1189 	pdata->host_node = of_graph_get_remote_node(np, 0, 0);
1190 
1191 	if (!pdata->host_node) {
1192 		DRM_ERROR("remote dsi host node not found\n");
1193 		return -ENODEV;
1194 	}
1195 
1196 	return 0;
1197 }
1198 
1199 static int ti_sn_bridge_probe(struct auxiliary_device *adev,
1200 			      const struct auxiliary_device_id *id)
1201 {
1202 	struct ti_sn65dsi86 *pdata = dev_get_drvdata(adev->dev.parent);
1203 	struct device_node *np = pdata->dev->of_node;
1204 	struct drm_panel *panel;
1205 	int ret;
1206 
1207 	ret = drm_of_find_panel_or_bridge(np, 1, 0, &panel, NULL);
1208 	if (ret)
1209 		return dev_err_probe(&adev->dev, ret,
1210 				     "could not find any panel node\n");
1211 
1212 	pdata->next_bridge = devm_drm_panel_bridge_add(pdata->dev, panel);
1213 	if (IS_ERR(pdata->next_bridge)) {
1214 		DRM_ERROR("failed to create panel bridge\n");
1215 		return PTR_ERR(pdata->next_bridge);
1216 	}
1217 
1218 	ti_sn_bridge_parse_lanes(pdata, np);
1219 
1220 	ret = ti_sn_bridge_parse_dsi_host(pdata);
1221 	if (ret)
1222 		return ret;
1223 
1224 	pdata->bridge.funcs = &ti_sn_bridge_funcs;
1225 	pdata->bridge.of_node = np;
1226 
1227 	drm_bridge_add(&pdata->bridge);
1228 
1229 	return 0;
1230 }
1231 
1232 static void ti_sn_bridge_remove(struct auxiliary_device *adev)
1233 {
1234 	struct ti_sn65dsi86 *pdata = dev_get_drvdata(adev->dev.parent);
1235 
1236 	if (!pdata)
1237 		return;
1238 
1239 	if (pdata->dsi) {
1240 		mipi_dsi_detach(pdata->dsi);
1241 		mipi_dsi_device_unregister(pdata->dsi);
1242 	}
1243 
1244 	drm_bridge_remove(&pdata->bridge);
1245 
1246 	of_node_put(pdata->host_node);
1247 }
1248 
1249 static const struct auxiliary_device_id ti_sn_bridge_id_table[] = {
1250 	{ .name = "ti_sn65dsi86.bridge", },
1251 	{},
1252 };
1253 
1254 static struct auxiliary_driver ti_sn_bridge_driver = {
1255 	.name = "bridge",
1256 	.probe = ti_sn_bridge_probe,
1257 	.remove = ti_sn_bridge_remove,
1258 	.id_table = ti_sn_bridge_id_table,
1259 };
1260 
1261 /* -----------------------------------------------------------------------------
1262  * GPIO Controller
1263  */
1264 
1265 #if defined(CONFIG_OF_GPIO)
1266 
1267 static int tn_sn_bridge_of_xlate(struct gpio_chip *chip,
1268 				 const struct of_phandle_args *gpiospec,
1269 				 u32 *flags)
1270 {
1271 	if (WARN_ON(gpiospec->args_count < chip->of_gpio_n_cells))
1272 		return -EINVAL;
1273 
1274 	if (gpiospec->args[0] > chip->ngpio || gpiospec->args[0] < 1)
1275 		return -EINVAL;
1276 
1277 	if (flags)
1278 		*flags = gpiospec->args[1];
1279 
1280 	return gpiospec->args[0] - SN_GPIO_PHYSICAL_OFFSET;
1281 }
1282 
1283 static int ti_sn_bridge_gpio_get_direction(struct gpio_chip *chip,
1284 					   unsigned int offset)
1285 {
1286 	struct ti_sn65dsi86 *pdata = gpiochip_get_data(chip);
1287 
1288 	/*
1289 	 * We already have to keep track of the direction because we use
1290 	 * that to figure out whether we've powered the device.  We can
1291 	 * just return that rather than (maybe) powering up the device
1292 	 * to ask its direction.
1293 	 */
1294 	return test_bit(offset, pdata->gchip_output) ?
1295 		GPIO_LINE_DIRECTION_OUT : GPIO_LINE_DIRECTION_IN;
1296 }
1297 
1298 static int ti_sn_bridge_gpio_get(struct gpio_chip *chip, unsigned int offset)
1299 {
1300 	struct ti_sn65dsi86 *pdata = gpiochip_get_data(chip);
1301 	unsigned int val;
1302 	int ret;
1303 
1304 	/*
1305 	 * When the pin is an input we don't forcibly keep the bridge
1306 	 * powered--we just power it on to read the pin.  NOTE: part of
1307 	 * the reason this works is that the bridge defaults (when
1308 	 * powered back on) to all 4 GPIOs being configured as GPIO input.
1309 	 * Also note that if something else is keeping the chip powered the
1310 	 * pm_runtime functions are lightweight increments of a refcount.
1311 	 */
1312 	pm_runtime_get_sync(pdata->dev);
1313 	ret = regmap_read(pdata->regmap, SN_GPIO_IO_REG, &val);
1314 	pm_runtime_put_autosuspend(pdata->dev);
1315 
1316 	if (ret)
1317 		return ret;
1318 
1319 	return !!(val & BIT(SN_GPIO_INPUT_SHIFT + offset));
1320 }
1321 
1322 static void ti_sn_bridge_gpio_set(struct gpio_chip *chip, unsigned int offset,
1323 				  int val)
1324 {
1325 	struct ti_sn65dsi86 *pdata = gpiochip_get_data(chip);
1326 	int ret;
1327 
1328 	if (!test_bit(offset, pdata->gchip_output)) {
1329 		dev_err(pdata->dev, "Ignoring GPIO set while input\n");
1330 		return;
1331 	}
1332 
1333 	val &= 1;
1334 	ret = regmap_update_bits(pdata->regmap, SN_GPIO_IO_REG,
1335 				 BIT(SN_GPIO_OUTPUT_SHIFT + offset),
1336 				 val << (SN_GPIO_OUTPUT_SHIFT + offset));
1337 	if (ret)
1338 		dev_warn(pdata->dev,
1339 			 "Failed to set bridge GPIO %u: %d\n", offset, ret);
1340 }
1341 
1342 static int ti_sn_bridge_gpio_direction_input(struct gpio_chip *chip,
1343 					     unsigned int offset)
1344 {
1345 	struct ti_sn65dsi86 *pdata = gpiochip_get_data(chip);
1346 	int shift = offset * 2;
1347 	int ret;
1348 
1349 	if (!test_and_clear_bit(offset, pdata->gchip_output))
1350 		return 0;
1351 
1352 	ret = regmap_update_bits(pdata->regmap, SN_GPIO_CTRL_REG,
1353 				 SN_GPIO_MUX_MASK << shift,
1354 				 SN_GPIO_MUX_INPUT << shift);
1355 	if (ret) {
1356 		set_bit(offset, pdata->gchip_output);
1357 		return ret;
1358 	}
1359 
1360 	/*
1361 	 * NOTE: if nobody else is powering the device this may fully power
1362 	 * it off and when it comes back it will have lost all state, but
1363 	 * that's OK because the default is input and we're now an input.
1364 	 */
1365 	pm_runtime_put_autosuspend(pdata->dev);
1366 
1367 	return 0;
1368 }
1369 
1370 static int ti_sn_bridge_gpio_direction_output(struct gpio_chip *chip,
1371 					      unsigned int offset, int val)
1372 {
1373 	struct ti_sn65dsi86 *pdata = gpiochip_get_data(chip);
1374 	int shift = offset * 2;
1375 	int ret;
1376 
1377 	if (test_and_set_bit(offset, pdata->gchip_output))
1378 		return 0;
1379 
1380 	pm_runtime_get_sync(pdata->dev);
1381 
1382 	/* Set value first to avoid glitching */
1383 	ti_sn_bridge_gpio_set(chip, offset, val);
1384 
1385 	/* Set direction */
1386 	ret = regmap_update_bits(pdata->regmap, SN_GPIO_CTRL_REG,
1387 				 SN_GPIO_MUX_MASK << shift,
1388 				 SN_GPIO_MUX_OUTPUT << shift);
1389 	if (ret) {
1390 		clear_bit(offset, pdata->gchip_output);
1391 		pm_runtime_put_autosuspend(pdata->dev);
1392 	}
1393 
1394 	return ret;
1395 }
1396 
1397 static void ti_sn_bridge_gpio_free(struct gpio_chip *chip, unsigned int offset)
1398 {
1399 	/* We won't keep pm_runtime if we're input, so switch there on free */
1400 	ti_sn_bridge_gpio_direction_input(chip, offset);
1401 }
1402 
1403 static const char * const ti_sn_bridge_gpio_names[SN_NUM_GPIOS] = {
1404 	"GPIO1", "GPIO2", "GPIO3", "GPIO4"
1405 };
1406 
1407 static int ti_sn_gpio_probe(struct auxiliary_device *adev,
1408 			    const struct auxiliary_device_id *id)
1409 {
1410 	struct ti_sn65dsi86 *pdata = dev_get_drvdata(adev->dev.parent);
1411 	int ret;
1412 
1413 	/* Only init if someone is going to use us as a GPIO controller */
1414 	if (!of_property_read_bool(pdata->dev->of_node, "gpio-controller"))
1415 		return 0;
1416 
1417 	pdata->gchip.label = dev_name(pdata->dev);
1418 	pdata->gchip.parent = pdata->dev;
1419 	pdata->gchip.owner = THIS_MODULE;
1420 	pdata->gchip.of_xlate = tn_sn_bridge_of_xlate;
1421 	pdata->gchip.of_gpio_n_cells = 2;
1422 	pdata->gchip.free = ti_sn_bridge_gpio_free;
1423 	pdata->gchip.get_direction = ti_sn_bridge_gpio_get_direction;
1424 	pdata->gchip.direction_input = ti_sn_bridge_gpio_direction_input;
1425 	pdata->gchip.direction_output = ti_sn_bridge_gpio_direction_output;
1426 	pdata->gchip.get = ti_sn_bridge_gpio_get;
1427 	pdata->gchip.set = ti_sn_bridge_gpio_set;
1428 	pdata->gchip.can_sleep = true;
1429 	pdata->gchip.names = ti_sn_bridge_gpio_names;
1430 	pdata->gchip.ngpio = SN_NUM_GPIOS;
1431 	pdata->gchip.base = -1;
1432 	ret = devm_gpiochip_add_data(&adev->dev, &pdata->gchip, pdata);
1433 	if (ret)
1434 		dev_err(pdata->dev, "can't add gpio chip\n");
1435 
1436 	return ret;
1437 }
1438 
1439 static const struct auxiliary_device_id ti_sn_gpio_id_table[] = {
1440 	{ .name = "ti_sn65dsi86.gpio", },
1441 	{},
1442 };
1443 
1444 MODULE_DEVICE_TABLE(auxiliary, ti_sn_gpio_id_table);
1445 
1446 static struct auxiliary_driver ti_sn_gpio_driver = {
1447 	.name = "gpio",
1448 	.probe = ti_sn_gpio_probe,
1449 	.id_table = ti_sn_gpio_id_table,
1450 };
1451 
1452 static int __init ti_sn_gpio_register(void)
1453 {
1454 	return auxiliary_driver_register(&ti_sn_gpio_driver);
1455 }
1456 
1457 static void ti_sn_gpio_unregister(void)
1458 {
1459 	auxiliary_driver_unregister(&ti_sn_gpio_driver);
1460 }
1461 
1462 #else
1463 
1464 static inline int ti_sn_gpio_register(void) { return 0; }
1465 static inline void ti_sn_gpio_unregister(void) {}
1466 
1467 #endif
1468 
1469 /* -----------------------------------------------------------------------------
1470  * Probe & Remove
1471  */
1472 
1473 static void ti_sn65dsi86_runtime_disable(void *data)
1474 {
1475 	pm_runtime_disable(data);
1476 }
1477 
1478 static int ti_sn65dsi86_parse_regulators(struct ti_sn65dsi86 *pdata)
1479 {
1480 	unsigned int i;
1481 	const char * const ti_sn_bridge_supply_names[] = {
1482 		"vcca", "vcc", "vccio", "vpll",
1483 	};
1484 
1485 	for (i = 0; i < SN_REGULATOR_SUPPLY_NUM; i++)
1486 		pdata->supplies[i].supply = ti_sn_bridge_supply_names[i];
1487 
1488 	return devm_regulator_bulk_get(pdata->dev, SN_REGULATOR_SUPPLY_NUM,
1489 				       pdata->supplies);
1490 }
1491 
1492 static int ti_sn65dsi86_probe(struct i2c_client *client,
1493 			      const struct i2c_device_id *id)
1494 {
1495 	struct device *dev = &client->dev;
1496 	struct ti_sn65dsi86 *pdata;
1497 	int ret;
1498 
1499 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
1500 		DRM_ERROR("device doesn't support I2C\n");
1501 		return -ENODEV;
1502 	}
1503 
1504 	pdata = devm_kzalloc(dev, sizeof(struct ti_sn65dsi86), GFP_KERNEL);
1505 	if (!pdata)
1506 		return -ENOMEM;
1507 	dev_set_drvdata(dev, pdata);
1508 	pdata->dev = dev;
1509 
1510 	mutex_init(&pdata->comms_mutex);
1511 
1512 	pdata->regmap = devm_regmap_init_i2c(client,
1513 					     &ti_sn65dsi86_regmap_config);
1514 	if (IS_ERR(pdata->regmap))
1515 		return dev_err_probe(dev, PTR_ERR(pdata->regmap),
1516 				     "regmap i2c init failed\n");
1517 
1518 	pdata->enable_gpio = devm_gpiod_get_optional(dev, "enable",
1519 						     GPIOD_OUT_LOW);
1520 	if (IS_ERR(pdata->enable_gpio))
1521 		return dev_err_probe(dev, PTR_ERR(pdata->enable_gpio),
1522 				     "failed to get enable gpio from DT\n");
1523 
1524 	ret = ti_sn65dsi86_parse_regulators(pdata);
1525 	if (ret)
1526 		return dev_err_probe(dev, ret, "failed to parse regulators\n");
1527 
1528 	pdata->refclk = devm_clk_get_optional(dev, "refclk");
1529 	if (IS_ERR(pdata->refclk))
1530 		return dev_err_probe(dev, PTR_ERR(pdata->refclk),
1531 				     "failed to get reference clock\n");
1532 
1533 	pm_runtime_enable(dev);
1534 	ret = devm_add_action_or_reset(dev, ti_sn65dsi86_runtime_disable, dev);
1535 	if (ret)
1536 		return ret;
1537 	pm_runtime_set_autosuspend_delay(pdata->dev, 500);
1538 	pm_runtime_use_autosuspend(pdata->dev);
1539 
1540 	ti_sn65dsi86_debugfs_init(pdata);
1541 
1542 	/*
1543 	 * Break ourselves up into a collection of aux devices. The only real
1544 	 * motiviation here is to solve the chicken-and-egg problem of probe
1545 	 * ordering. The bridge wants the panel to be there when it probes.
1546 	 * The panel wants its HPD GPIO (provided by sn65dsi86 on some boards)
1547 	 * when it probes. The panel and maybe backlight might want the DDC
1548 	 * bus. Soon the PWM provided by the bridge chip will have the same
1549 	 * problem. Having sub-devices allows the some sub devices to finish
1550 	 * probing even if others return -EPROBE_DEFER and gets us around the
1551 	 * problems.
1552 	 */
1553 
1554 	if (IS_ENABLED(CONFIG_OF_GPIO)) {
1555 		ret = ti_sn65dsi86_add_aux_device(pdata, &pdata->gpio_aux, "gpio");
1556 		if (ret)
1557 			return ret;
1558 	}
1559 
1560 	/*
1561 	 * NOTE: At the end of the AUX channel probe we'll add the aux device
1562 	 * for the bridge. This is because the bridge can't be used until the
1563 	 * AUX channel is there and this is a very simple solution to the
1564 	 * dependency problem.
1565 	 */
1566 	return ti_sn65dsi86_add_aux_device(pdata, &pdata->aux_aux, "aux");
1567 }
1568 
1569 static struct i2c_device_id ti_sn65dsi86_id[] = {
1570 	{ "ti,sn65dsi86", 0},
1571 	{},
1572 };
1573 MODULE_DEVICE_TABLE(i2c, ti_sn65dsi86_id);
1574 
1575 static const struct of_device_id ti_sn65dsi86_match_table[] = {
1576 	{.compatible = "ti,sn65dsi86"},
1577 	{},
1578 };
1579 MODULE_DEVICE_TABLE(of, ti_sn65dsi86_match_table);
1580 
1581 static struct i2c_driver ti_sn65dsi86_driver = {
1582 	.driver = {
1583 		.name = "ti_sn65dsi86",
1584 		.of_match_table = ti_sn65dsi86_match_table,
1585 		.pm = &ti_sn65dsi86_pm_ops,
1586 	},
1587 	.probe = ti_sn65dsi86_probe,
1588 	.id_table = ti_sn65dsi86_id,
1589 };
1590 
1591 static int __init ti_sn65dsi86_init(void)
1592 {
1593 	int ret;
1594 
1595 	ret = i2c_add_driver(&ti_sn65dsi86_driver);
1596 	if (ret)
1597 		return ret;
1598 
1599 	ret = ti_sn_gpio_register();
1600 	if (ret)
1601 		goto err_main_was_registered;
1602 
1603 	ret = auxiliary_driver_register(&ti_sn_aux_driver);
1604 	if (ret)
1605 		goto err_gpio_was_registered;
1606 
1607 	ret = auxiliary_driver_register(&ti_sn_bridge_driver);
1608 	if (ret)
1609 		goto err_aux_was_registered;
1610 
1611 	return 0;
1612 
1613 err_aux_was_registered:
1614 	auxiliary_driver_unregister(&ti_sn_aux_driver);
1615 err_gpio_was_registered:
1616 	ti_sn_gpio_unregister();
1617 err_main_was_registered:
1618 	i2c_del_driver(&ti_sn65dsi86_driver);
1619 
1620 	return ret;
1621 }
1622 module_init(ti_sn65dsi86_init);
1623 
1624 static void __exit ti_sn65dsi86_exit(void)
1625 {
1626 	auxiliary_driver_unregister(&ti_sn_bridge_driver);
1627 	auxiliary_driver_unregister(&ti_sn_aux_driver);
1628 	ti_sn_gpio_unregister();
1629 	i2c_del_driver(&ti_sn65dsi86_driver);
1630 }
1631 module_exit(ti_sn65dsi86_exit);
1632 
1633 MODULE_AUTHOR("Sandeep Panda <spanda@codeaurora.org>");
1634 MODULE_DESCRIPTION("sn65dsi86 DSI to eDP bridge driver");
1635 MODULE_LICENSE("GPL v2");
1636