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/bits.h>
8 #include <linux/clk.h>
9 #include <linux/debugfs.h>
10 #include <linux/gpio/consumer.h>
11 #include <linux/gpio/driver.h>
12 #include <linux/i2c.h>
13 #include <linux/iopoll.h>
14 #include <linux/module.h>
15 #include <linux/of_graph.h>
16 #include <linux/pm_runtime.h>
17 #include <linux/regmap.h>
18 #include <linux/regulator/consumer.h>
19 
20 #include <drm/drm_atomic.h>
21 #include <drm/drm_atomic_helper.h>
22 #include <drm/drm_bridge.h>
23 #include <drm/drm_dp_helper.h>
24 #include <drm/drm_mipi_dsi.h>
25 #include <drm/drm_of.h>
26 #include <drm/drm_panel.h>
27 #include <drm/drm_print.h>
28 #include <drm/drm_probe_helper.h>
29 
30 #define SN_DEVICE_REV_REG			0x08
31 #define SN_DPPLL_SRC_REG			0x0A
32 #define  DPPLL_CLK_SRC_DSICLK			BIT(0)
33 #define  REFCLK_FREQ_MASK			GENMASK(3, 1)
34 #define  REFCLK_FREQ(x)				((x) << 1)
35 #define  DPPLL_SRC_DP_PLL_LOCK			BIT(7)
36 #define SN_PLL_ENABLE_REG			0x0D
37 #define SN_DSI_LANES_REG			0x10
38 #define  CHA_DSI_LANES_MASK			GENMASK(4, 3)
39 #define  CHA_DSI_LANES(x)			((x) << 3)
40 #define SN_DSIA_CLK_FREQ_REG			0x12
41 #define SN_CHA_ACTIVE_LINE_LENGTH_LOW_REG	0x20
42 #define SN_CHA_VERTICAL_DISPLAY_SIZE_LOW_REG	0x24
43 #define SN_CHA_HSYNC_PULSE_WIDTH_LOW_REG	0x2C
44 #define SN_CHA_HSYNC_PULSE_WIDTH_HIGH_REG	0x2D
45 #define  CHA_HSYNC_POLARITY			BIT(7)
46 #define SN_CHA_VSYNC_PULSE_WIDTH_LOW_REG	0x30
47 #define SN_CHA_VSYNC_PULSE_WIDTH_HIGH_REG	0x31
48 #define  CHA_VSYNC_POLARITY			BIT(7)
49 #define SN_CHA_HORIZONTAL_BACK_PORCH_REG	0x34
50 #define SN_CHA_VERTICAL_BACK_PORCH_REG		0x36
51 #define SN_CHA_HORIZONTAL_FRONT_PORCH_REG	0x38
52 #define SN_CHA_VERTICAL_FRONT_PORCH_REG		0x3A
53 #define SN_LN_ASSIGN_REG			0x59
54 #define  LN_ASSIGN_WIDTH			2
55 #define SN_ENH_FRAME_REG			0x5A
56 #define  VSTREAM_ENABLE				BIT(3)
57 #define  LN_POLRS_OFFSET			4
58 #define  LN_POLRS_MASK				0xf0
59 #define SN_DATA_FORMAT_REG			0x5B
60 #define  BPP_18_RGB				BIT(0)
61 #define SN_HPD_DISABLE_REG			0x5C
62 #define  HPD_DISABLE				BIT(0)
63 #define SN_GPIO_IO_REG				0x5E
64 #define  SN_GPIO_INPUT_SHIFT			4
65 #define  SN_GPIO_OUTPUT_SHIFT			0
66 #define SN_GPIO_CTRL_REG			0x5F
67 #define  SN_GPIO_MUX_INPUT			0
68 #define  SN_GPIO_MUX_OUTPUT			1
69 #define  SN_GPIO_MUX_SPECIAL			2
70 #define  SN_GPIO_MUX_MASK			0x3
71 #define SN_AUX_WDATA_REG(x)			(0x64 + (x))
72 #define SN_AUX_ADDR_19_16_REG			0x74
73 #define SN_AUX_ADDR_15_8_REG			0x75
74 #define SN_AUX_ADDR_7_0_REG			0x76
75 #define SN_AUX_LENGTH_REG			0x77
76 #define SN_AUX_CMD_REG				0x78
77 #define  AUX_CMD_SEND				BIT(0)
78 #define  AUX_CMD_REQ(x)				((x) << 4)
79 #define SN_AUX_RDATA_REG(x)			(0x79 + (x))
80 #define SN_SSC_CONFIG_REG			0x93
81 #define  DP_NUM_LANES_MASK			GENMASK(5, 4)
82 #define  DP_NUM_LANES(x)			((x) << 4)
83 #define SN_DATARATE_CONFIG_REG			0x94
84 #define  DP_DATARATE_MASK			GENMASK(7, 5)
85 #define  DP_DATARATE(x)				((x) << 5)
86 #define SN_ML_TX_MODE_REG			0x96
87 #define  ML_TX_MAIN_LINK_OFF			0
88 #define  ML_TX_NORMAL_MODE			BIT(0)
89 #define SN_AUX_CMD_STATUS_REG			0xF4
90 #define  AUX_IRQ_STATUS_AUX_RPLY_TOUT		BIT(3)
91 #define  AUX_IRQ_STATUS_AUX_SHORT		BIT(5)
92 #define  AUX_IRQ_STATUS_NAT_I2C_FAIL		BIT(6)
93 
94 #define MIN_DSI_CLK_FREQ_MHZ	40
95 
96 /* fudge factor required to account for 8b/10b encoding */
97 #define DP_CLK_FUDGE_NUM	10
98 #define DP_CLK_FUDGE_DEN	8
99 
100 /* Matches DP_AUX_MAX_PAYLOAD_BYTES (for now) */
101 #define SN_AUX_MAX_PAYLOAD_BYTES	16
102 
103 #define SN_REGULATOR_SUPPLY_NUM		4
104 
105 #define SN_MAX_DP_LANES			4
106 #define SN_NUM_GPIOS			4
107 #define SN_GPIO_PHYSICAL_OFFSET		1
108 
109 #define SN_LINK_TRAINING_TRIES		10
110 
111 /**
112  * struct ti_sn_bridge - Platform data for ti-sn65dsi86 driver.
113  * @dev:          Pointer to our device.
114  * @regmap:       Regmap for accessing i2c.
115  * @aux:          Our aux channel.
116  * @bridge:       Our bridge.
117  * @connector:    Our connector.
118  * @debugfs:      Used for managing our debugfs.
119  * @host_node:    Remote DSI node.
120  * @dsi:          Our MIPI DSI source.
121  * @refclk:       Our reference clock.
122  * @panel:        Our panel.
123  * @enable_gpio:  The GPIO we toggle to enable the bridge.
124  * @supplies:     Data for bulk enabling/disabling our regulators.
125  * @dp_lanes:     Count of dp_lanes we're using.
126  * @ln_assign:    Value to program to the LN_ASSIGN register.
127  * @ln_polrs:     Value for the 4-bit LN_POLRS field of SN_ENH_FRAME_REG.
128  *
129  * @gchip:        If we expose our GPIOs, this is used.
130  * @gchip_output: A cache of whether we've set GPIOs to output.  This
131  *                serves double-duty of keeping track of the direction and
132  *                also keeping track of whether we've incremented the
133  *                pm_runtime reference count for this pin, which we do
134  *                whenever a pin is configured as an output.  This is a
135  *                bitmap so we can do atomic ops on it without an extra
136  *                lock so concurrent users of our 4 GPIOs don't stomp on
137  *                each other's read-modify-write.
138  */
139 struct ti_sn_bridge {
140 	struct device			*dev;
141 	struct regmap			*regmap;
142 	struct drm_dp_aux		aux;
143 	struct drm_bridge		bridge;
144 	struct drm_connector		connector;
145 	struct dentry			*debugfs;
146 	struct device_node		*host_node;
147 	struct mipi_dsi_device		*dsi;
148 	struct clk			*refclk;
149 	struct drm_panel		*panel;
150 	struct gpio_desc		*enable_gpio;
151 	struct regulator_bulk_data	supplies[SN_REGULATOR_SUPPLY_NUM];
152 	int				dp_lanes;
153 	u8				ln_assign;
154 	u8				ln_polrs;
155 
156 #if defined(CONFIG_OF_GPIO)
157 	struct gpio_chip		gchip;
158 	DECLARE_BITMAP(gchip_output, SN_NUM_GPIOS);
159 #endif
160 };
161 
162 static const struct regmap_range ti_sn_bridge_volatile_ranges[] = {
163 	{ .range_min = 0, .range_max = 0xFF },
164 };
165 
166 static const struct regmap_access_table ti_sn_bridge_volatile_table = {
167 	.yes_ranges = ti_sn_bridge_volatile_ranges,
168 	.n_yes_ranges = ARRAY_SIZE(ti_sn_bridge_volatile_ranges),
169 };
170 
171 static const struct regmap_config ti_sn_bridge_regmap_config = {
172 	.reg_bits = 8,
173 	.val_bits = 8,
174 	.volatile_table = &ti_sn_bridge_volatile_table,
175 	.cache_type = REGCACHE_NONE,
176 };
177 
178 static void ti_sn_bridge_write_u16(struct ti_sn_bridge *pdata,
179 				   unsigned int reg, u16 val)
180 {
181 	regmap_write(pdata->regmap, reg, val & 0xFF);
182 	regmap_write(pdata->regmap, reg + 1, val >> 8);
183 }
184 
185 static int __maybe_unused ti_sn_bridge_resume(struct device *dev)
186 {
187 	struct ti_sn_bridge *pdata = dev_get_drvdata(dev);
188 	int ret;
189 
190 	ret = regulator_bulk_enable(SN_REGULATOR_SUPPLY_NUM, pdata->supplies);
191 	if (ret) {
192 		DRM_ERROR("failed to enable supplies %d\n", ret);
193 		return ret;
194 	}
195 
196 	gpiod_set_value(pdata->enable_gpio, 1);
197 
198 	return ret;
199 }
200 
201 static int __maybe_unused ti_sn_bridge_suspend(struct device *dev)
202 {
203 	struct ti_sn_bridge *pdata = dev_get_drvdata(dev);
204 	int ret;
205 
206 	gpiod_set_value(pdata->enable_gpio, 0);
207 
208 	ret = regulator_bulk_disable(SN_REGULATOR_SUPPLY_NUM, pdata->supplies);
209 	if (ret)
210 		DRM_ERROR("failed to disable supplies %d\n", ret);
211 
212 	return ret;
213 }
214 
215 static const struct dev_pm_ops ti_sn_bridge_pm_ops = {
216 	SET_RUNTIME_PM_OPS(ti_sn_bridge_suspend, ti_sn_bridge_resume, NULL)
217 	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
218 				pm_runtime_force_resume)
219 };
220 
221 static int status_show(struct seq_file *s, void *data)
222 {
223 	struct ti_sn_bridge *pdata = s->private;
224 	unsigned int reg, val;
225 
226 	seq_puts(s, "STATUS REGISTERS:\n");
227 
228 	pm_runtime_get_sync(pdata->dev);
229 
230 	/* IRQ Status Registers, see Table 31 in datasheet */
231 	for (reg = 0xf0; reg <= 0xf8; reg++) {
232 		regmap_read(pdata->regmap, reg, &val);
233 		seq_printf(s, "[0x%02x] = 0x%08x\n", reg, val);
234 	}
235 
236 	pm_runtime_put(pdata->dev);
237 
238 	return 0;
239 }
240 
241 DEFINE_SHOW_ATTRIBUTE(status);
242 
243 static void ti_sn_debugfs_init(struct ti_sn_bridge *pdata)
244 {
245 	pdata->debugfs = debugfs_create_dir(dev_name(pdata->dev), NULL);
246 
247 	debugfs_create_file("status", 0600, pdata->debugfs, pdata,
248 			&status_fops);
249 }
250 
251 static void ti_sn_debugfs_remove(struct ti_sn_bridge *pdata)
252 {
253 	debugfs_remove_recursive(pdata->debugfs);
254 	pdata->debugfs = NULL;
255 }
256 
257 /* Connector funcs */
258 static struct ti_sn_bridge *
259 connector_to_ti_sn_bridge(struct drm_connector *connector)
260 {
261 	return container_of(connector, struct ti_sn_bridge, connector);
262 }
263 
264 static int ti_sn_bridge_connector_get_modes(struct drm_connector *connector)
265 {
266 	struct ti_sn_bridge *pdata = connector_to_ti_sn_bridge(connector);
267 
268 	return drm_panel_get_modes(pdata->panel, connector);
269 }
270 
271 static enum drm_mode_status
272 ti_sn_bridge_connector_mode_valid(struct drm_connector *connector,
273 				  struct drm_display_mode *mode)
274 {
275 	/* maximum supported resolution is 4K at 60 fps */
276 	if (mode->clock > 594000)
277 		return MODE_CLOCK_HIGH;
278 
279 	return MODE_OK;
280 }
281 
282 static struct drm_connector_helper_funcs ti_sn_bridge_connector_helper_funcs = {
283 	.get_modes = ti_sn_bridge_connector_get_modes,
284 	.mode_valid = ti_sn_bridge_connector_mode_valid,
285 };
286 
287 static enum drm_connector_status
288 ti_sn_bridge_connector_detect(struct drm_connector *connector, bool force)
289 {
290 	/**
291 	 * TODO: Currently if drm_panel is present, then always
292 	 * return the status as connected. Need to add support to detect
293 	 * device state for hot pluggable scenarios.
294 	 */
295 	return connector_status_connected;
296 }
297 
298 static const struct drm_connector_funcs ti_sn_bridge_connector_funcs = {
299 	.fill_modes = drm_helper_probe_single_connector_modes,
300 	.detect = ti_sn_bridge_connector_detect,
301 	.destroy = drm_connector_cleanup,
302 	.reset = drm_atomic_helper_connector_reset,
303 	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
304 	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
305 };
306 
307 static struct ti_sn_bridge *bridge_to_ti_sn_bridge(struct drm_bridge *bridge)
308 {
309 	return container_of(bridge, struct ti_sn_bridge, bridge);
310 }
311 
312 static int ti_sn_bridge_parse_regulators(struct ti_sn_bridge *pdata)
313 {
314 	unsigned int i;
315 	const char * const ti_sn_bridge_supply_names[] = {
316 		"vcca", "vcc", "vccio", "vpll",
317 	};
318 
319 	for (i = 0; i < SN_REGULATOR_SUPPLY_NUM; i++)
320 		pdata->supplies[i].supply = ti_sn_bridge_supply_names[i];
321 
322 	return devm_regulator_bulk_get(pdata->dev, SN_REGULATOR_SUPPLY_NUM,
323 				       pdata->supplies);
324 }
325 
326 static int ti_sn_bridge_attach(struct drm_bridge *bridge,
327 			       enum drm_bridge_attach_flags flags)
328 {
329 	int ret, val;
330 	struct ti_sn_bridge *pdata = bridge_to_ti_sn_bridge(bridge);
331 	struct mipi_dsi_host *host;
332 	struct mipi_dsi_device *dsi;
333 	const struct mipi_dsi_device_info info = { .type = "ti_sn_bridge",
334 						   .channel = 0,
335 						   .node = NULL,
336 						 };
337 
338 	if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) {
339 		DRM_ERROR("Fix bridge driver to make connector optional!");
340 		return -EINVAL;
341 	}
342 
343 	ret = drm_connector_init(bridge->dev, &pdata->connector,
344 				 &ti_sn_bridge_connector_funcs,
345 				 DRM_MODE_CONNECTOR_eDP);
346 	if (ret) {
347 		DRM_ERROR("Failed to initialize connector with drm\n");
348 		return ret;
349 	}
350 
351 	drm_connector_helper_add(&pdata->connector,
352 				 &ti_sn_bridge_connector_helper_funcs);
353 	drm_connector_attach_encoder(&pdata->connector, bridge->encoder);
354 
355 	/*
356 	 * TODO: ideally finding host resource and dsi dev registration needs
357 	 * to be done in bridge probe. But some existing DSI host drivers will
358 	 * wait for any of the drm_bridge/drm_panel to get added to the global
359 	 * bridge/panel list, before completing their probe. So if we do the
360 	 * dsi dev registration part in bridge probe, before populating in
361 	 * the global bridge list, then it will cause deadlock as dsi host probe
362 	 * will never complete, neither our bridge probe. So keeping it here
363 	 * will satisfy most of the existing host drivers. Once the host driver
364 	 * is fixed we can move the below code to bridge probe safely.
365 	 */
366 	host = of_find_mipi_dsi_host_by_node(pdata->host_node);
367 	if (!host) {
368 		DRM_ERROR("failed to find dsi host\n");
369 		ret = -ENODEV;
370 		goto err_dsi_host;
371 	}
372 
373 	dsi = mipi_dsi_device_register_full(host, &info);
374 	if (IS_ERR(dsi)) {
375 		DRM_ERROR("failed to create dsi device\n");
376 		ret = PTR_ERR(dsi);
377 		goto err_dsi_host;
378 	}
379 
380 	/* TODO: setting to 4 MIPI lanes always for now */
381 	dsi->lanes = 4;
382 	dsi->format = MIPI_DSI_FMT_RGB888;
383 	dsi->mode_flags = MIPI_DSI_MODE_VIDEO;
384 
385 	/* check if continuous dsi clock is required or not */
386 	pm_runtime_get_sync(pdata->dev);
387 	regmap_read(pdata->regmap, SN_DPPLL_SRC_REG, &val);
388 	pm_runtime_put(pdata->dev);
389 	if (!(val & DPPLL_CLK_SRC_DSICLK))
390 		dsi->mode_flags |= MIPI_DSI_CLOCK_NON_CONTINUOUS;
391 
392 	ret = mipi_dsi_attach(dsi);
393 	if (ret < 0) {
394 		DRM_ERROR("failed to attach dsi to host\n");
395 		goto err_dsi_attach;
396 	}
397 	pdata->dsi = dsi;
398 
399 	return 0;
400 
401 err_dsi_attach:
402 	mipi_dsi_device_unregister(dsi);
403 err_dsi_host:
404 	drm_connector_cleanup(&pdata->connector);
405 	return ret;
406 }
407 
408 static void ti_sn_bridge_disable(struct drm_bridge *bridge)
409 {
410 	struct ti_sn_bridge *pdata = bridge_to_ti_sn_bridge(bridge);
411 
412 	drm_panel_disable(pdata->panel);
413 
414 	/* disable video stream */
415 	regmap_update_bits(pdata->regmap, SN_ENH_FRAME_REG, VSTREAM_ENABLE, 0);
416 	/* semi auto link training mode OFF */
417 	regmap_write(pdata->regmap, SN_ML_TX_MODE_REG, 0);
418 	/* disable DP PLL */
419 	regmap_write(pdata->regmap, SN_PLL_ENABLE_REG, 0);
420 
421 	drm_panel_unprepare(pdata->panel);
422 }
423 
424 static u32 ti_sn_bridge_get_dsi_freq(struct ti_sn_bridge *pdata)
425 {
426 	u32 bit_rate_khz, clk_freq_khz;
427 	struct drm_display_mode *mode =
428 		&pdata->bridge.encoder->crtc->state->adjusted_mode;
429 
430 	bit_rate_khz = mode->clock *
431 			mipi_dsi_pixel_format_to_bpp(pdata->dsi->format);
432 	clk_freq_khz = bit_rate_khz / (pdata->dsi->lanes * 2);
433 
434 	return clk_freq_khz;
435 }
436 
437 /* clk frequencies supported by bridge in Hz in case derived from REFCLK pin */
438 static const u32 ti_sn_bridge_refclk_lut[] = {
439 	12000000,
440 	19200000,
441 	26000000,
442 	27000000,
443 	38400000,
444 };
445 
446 /* clk frequencies supported by bridge in Hz in case derived from DACP/N pin */
447 static const u32 ti_sn_bridge_dsiclk_lut[] = {
448 	468000000,
449 	384000000,
450 	416000000,
451 	486000000,
452 	460800000,
453 };
454 
455 static void ti_sn_bridge_set_refclk_freq(struct ti_sn_bridge *pdata)
456 {
457 	int i;
458 	u32 refclk_rate;
459 	const u32 *refclk_lut;
460 	size_t refclk_lut_size;
461 
462 	if (pdata->refclk) {
463 		refclk_rate = clk_get_rate(pdata->refclk);
464 		refclk_lut = ti_sn_bridge_refclk_lut;
465 		refclk_lut_size = ARRAY_SIZE(ti_sn_bridge_refclk_lut);
466 		clk_prepare_enable(pdata->refclk);
467 	} else {
468 		refclk_rate = ti_sn_bridge_get_dsi_freq(pdata) * 1000;
469 		refclk_lut = ti_sn_bridge_dsiclk_lut;
470 		refclk_lut_size = ARRAY_SIZE(ti_sn_bridge_dsiclk_lut);
471 	}
472 
473 	/* for i equals to refclk_lut_size means default frequency */
474 	for (i = 0; i < refclk_lut_size; i++)
475 		if (refclk_lut[i] == refclk_rate)
476 			break;
477 
478 	regmap_update_bits(pdata->regmap, SN_DPPLL_SRC_REG, REFCLK_FREQ_MASK,
479 			   REFCLK_FREQ(i));
480 }
481 
482 static void ti_sn_bridge_set_dsi_rate(struct ti_sn_bridge *pdata)
483 {
484 	unsigned int bit_rate_mhz, clk_freq_mhz;
485 	unsigned int val;
486 	struct drm_display_mode *mode =
487 		&pdata->bridge.encoder->crtc->state->adjusted_mode;
488 
489 	/* set DSIA clk frequency */
490 	bit_rate_mhz = (mode->clock / 1000) *
491 			mipi_dsi_pixel_format_to_bpp(pdata->dsi->format);
492 	clk_freq_mhz = bit_rate_mhz / (pdata->dsi->lanes * 2);
493 
494 	/* for each increment in val, frequency increases by 5MHz */
495 	val = (MIN_DSI_CLK_FREQ_MHZ / 5) +
496 		(((clk_freq_mhz - MIN_DSI_CLK_FREQ_MHZ) / 5) & 0xFF);
497 	regmap_write(pdata->regmap, SN_DSIA_CLK_FREQ_REG, val);
498 }
499 
500 static unsigned int ti_sn_bridge_get_bpp(struct ti_sn_bridge *pdata)
501 {
502 	if (pdata->connector.display_info.bpc <= 6)
503 		return 18;
504 	else
505 		return 24;
506 }
507 
508 /*
509  * LUT index corresponds to register value and
510  * LUT values corresponds to dp data rate supported
511  * by the bridge in Mbps unit.
512  */
513 static const unsigned int ti_sn_bridge_dp_rate_lut[] = {
514 	0, 1620, 2160, 2430, 2700, 3240, 4320, 5400
515 };
516 
517 static int ti_sn_bridge_calc_min_dp_rate_idx(struct ti_sn_bridge *pdata)
518 {
519 	unsigned int bit_rate_khz, dp_rate_mhz;
520 	unsigned int i;
521 	struct drm_display_mode *mode =
522 		&pdata->bridge.encoder->crtc->state->adjusted_mode;
523 
524 	/* Calculate minimum bit rate based on our pixel clock. */
525 	bit_rate_khz = mode->clock * ti_sn_bridge_get_bpp(pdata);
526 
527 	/* Calculate minimum DP data rate, taking 80% as per DP spec */
528 	dp_rate_mhz = DIV_ROUND_UP(bit_rate_khz * DP_CLK_FUDGE_NUM,
529 				   1000 * pdata->dp_lanes * DP_CLK_FUDGE_DEN);
530 
531 	for (i = 1; i < ARRAY_SIZE(ti_sn_bridge_dp_rate_lut) - 1; i++)
532 		if (ti_sn_bridge_dp_rate_lut[i] >= dp_rate_mhz)
533 			break;
534 
535 	return i;
536 }
537 
538 static void ti_sn_bridge_read_valid_rates(struct ti_sn_bridge *pdata,
539 					  bool rate_valid[])
540 {
541 	unsigned int rate_per_200khz;
542 	unsigned int rate_mhz;
543 	u8 dpcd_val;
544 	int ret;
545 	int i, j;
546 
547 	ret = drm_dp_dpcd_readb(&pdata->aux, DP_EDP_DPCD_REV, &dpcd_val);
548 	if (ret != 1) {
549 		DRM_DEV_ERROR(pdata->dev,
550 			      "Can't read eDP rev (%d), assuming 1.1\n", ret);
551 		dpcd_val = DP_EDP_11;
552 	}
553 
554 	if (dpcd_val >= DP_EDP_14) {
555 		/* eDP 1.4 devices must provide a custom table */
556 		__le16 sink_rates[DP_MAX_SUPPORTED_RATES];
557 
558 		ret = drm_dp_dpcd_read(&pdata->aux, DP_SUPPORTED_LINK_RATES,
559 				       sink_rates, sizeof(sink_rates));
560 
561 		if (ret != sizeof(sink_rates)) {
562 			DRM_DEV_ERROR(pdata->dev,
563 				"Can't read supported rate table (%d)\n", ret);
564 
565 			/* By zeroing we'll fall back to DP_MAX_LINK_RATE. */
566 			memset(sink_rates, 0, sizeof(sink_rates));
567 		}
568 
569 		for (i = 0; i < ARRAY_SIZE(sink_rates); i++) {
570 			rate_per_200khz = le16_to_cpu(sink_rates[i]);
571 
572 			if (!rate_per_200khz)
573 				break;
574 
575 			rate_mhz = rate_per_200khz * 200 / 1000;
576 			for (j = 0;
577 			     j < ARRAY_SIZE(ti_sn_bridge_dp_rate_lut);
578 			     j++) {
579 				if (ti_sn_bridge_dp_rate_lut[j] == rate_mhz)
580 					rate_valid[j] = true;
581 			}
582 		}
583 
584 		for (i = 0; i < ARRAY_SIZE(ti_sn_bridge_dp_rate_lut); i++) {
585 			if (rate_valid[i])
586 				return;
587 		}
588 		DRM_DEV_ERROR(pdata->dev,
589 			      "No matching eDP rates in table; falling back\n");
590 	}
591 
592 	/* On older versions best we can do is use DP_MAX_LINK_RATE */
593 	ret = drm_dp_dpcd_readb(&pdata->aux, DP_MAX_LINK_RATE, &dpcd_val);
594 	if (ret != 1) {
595 		DRM_DEV_ERROR(pdata->dev,
596 			      "Can't read max rate (%d); assuming 5.4 GHz\n",
597 			      ret);
598 		dpcd_val = DP_LINK_BW_5_4;
599 	}
600 
601 	switch (dpcd_val) {
602 	default:
603 		DRM_DEV_ERROR(pdata->dev,
604 			      "Unexpected max rate (%#x); assuming 5.4 GHz\n",
605 			      (int)dpcd_val);
606 		fallthrough;
607 	case DP_LINK_BW_5_4:
608 		rate_valid[7] = 1;
609 		fallthrough;
610 	case DP_LINK_BW_2_7:
611 		rate_valid[4] = 1;
612 		fallthrough;
613 	case DP_LINK_BW_1_62:
614 		rate_valid[1] = 1;
615 		break;
616 	}
617 }
618 
619 static void ti_sn_bridge_set_video_timings(struct ti_sn_bridge *pdata)
620 {
621 	struct drm_display_mode *mode =
622 		&pdata->bridge.encoder->crtc->state->adjusted_mode;
623 	u8 hsync_polarity = 0, vsync_polarity = 0;
624 
625 	if (mode->flags & DRM_MODE_FLAG_PHSYNC)
626 		hsync_polarity = CHA_HSYNC_POLARITY;
627 	if (mode->flags & DRM_MODE_FLAG_PVSYNC)
628 		vsync_polarity = CHA_VSYNC_POLARITY;
629 
630 	ti_sn_bridge_write_u16(pdata, SN_CHA_ACTIVE_LINE_LENGTH_LOW_REG,
631 			       mode->hdisplay);
632 	ti_sn_bridge_write_u16(pdata, SN_CHA_VERTICAL_DISPLAY_SIZE_LOW_REG,
633 			       mode->vdisplay);
634 	regmap_write(pdata->regmap, SN_CHA_HSYNC_PULSE_WIDTH_LOW_REG,
635 		     (mode->hsync_end - mode->hsync_start) & 0xFF);
636 	regmap_write(pdata->regmap, SN_CHA_HSYNC_PULSE_WIDTH_HIGH_REG,
637 		     (((mode->hsync_end - mode->hsync_start) >> 8) & 0x7F) |
638 		     hsync_polarity);
639 	regmap_write(pdata->regmap, SN_CHA_VSYNC_PULSE_WIDTH_LOW_REG,
640 		     (mode->vsync_end - mode->vsync_start) & 0xFF);
641 	regmap_write(pdata->regmap, SN_CHA_VSYNC_PULSE_WIDTH_HIGH_REG,
642 		     (((mode->vsync_end - mode->vsync_start) >> 8) & 0x7F) |
643 		     vsync_polarity);
644 
645 	regmap_write(pdata->regmap, SN_CHA_HORIZONTAL_BACK_PORCH_REG,
646 		     (mode->htotal - mode->hsync_end) & 0xFF);
647 	regmap_write(pdata->regmap, SN_CHA_VERTICAL_BACK_PORCH_REG,
648 		     (mode->vtotal - mode->vsync_end) & 0xFF);
649 
650 	regmap_write(pdata->regmap, SN_CHA_HORIZONTAL_FRONT_PORCH_REG,
651 		     (mode->hsync_start - mode->hdisplay) & 0xFF);
652 	regmap_write(pdata->regmap, SN_CHA_VERTICAL_FRONT_PORCH_REG,
653 		     (mode->vsync_start - mode->vdisplay) & 0xFF);
654 
655 	usleep_range(10000, 10500); /* 10ms delay recommended by spec */
656 }
657 
658 static unsigned int ti_sn_get_max_lanes(struct ti_sn_bridge *pdata)
659 {
660 	u8 data;
661 	int ret;
662 
663 	ret = drm_dp_dpcd_readb(&pdata->aux, DP_MAX_LANE_COUNT, &data);
664 	if (ret != 1) {
665 		DRM_DEV_ERROR(pdata->dev,
666 			      "Can't read lane count (%d); assuming 4\n", ret);
667 		return 4;
668 	}
669 
670 	return data & DP_LANE_COUNT_MASK;
671 }
672 
673 static int ti_sn_link_training(struct ti_sn_bridge *pdata, int dp_rate_idx,
674 			       const char **last_err_str)
675 {
676 	unsigned int val;
677 	int ret;
678 	int i;
679 
680 	/* set dp clk frequency value */
681 	regmap_update_bits(pdata->regmap, SN_DATARATE_CONFIG_REG,
682 			   DP_DATARATE_MASK, DP_DATARATE(dp_rate_idx));
683 
684 	/* enable DP PLL */
685 	regmap_write(pdata->regmap, SN_PLL_ENABLE_REG, 1);
686 
687 	ret = regmap_read_poll_timeout(pdata->regmap, SN_DPPLL_SRC_REG, val,
688 				       val & DPPLL_SRC_DP_PLL_LOCK, 1000,
689 				       50 * 1000);
690 	if (ret) {
691 		*last_err_str = "DP_PLL_LOCK polling failed";
692 		goto exit;
693 	}
694 
695 	/*
696 	 * We'll try to link train several times.  As part of link training
697 	 * the bridge chip will write DP_SET_POWER_D0 to DP_SET_POWER.  If
698 	 * the panel isn't ready quite it might respond NAK here which means
699 	 * we need to try again.
700 	 */
701 	for (i = 0; i < SN_LINK_TRAINING_TRIES; i++) {
702 		/* Semi auto link training mode */
703 		regmap_write(pdata->regmap, SN_ML_TX_MODE_REG, 0x0A);
704 		ret = regmap_read_poll_timeout(pdata->regmap, SN_ML_TX_MODE_REG, val,
705 					       val == ML_TX_MAIN_LINK_OFF ||
706 					       val == ML_TX_NORMAL_MODE, 1000,
707 					       500 * 1000);
708 		if (ret) {
709 			*last_err_str = "Training complete polling failed";
710 		} else if (val == ML_TX_MAIN_LINK_OFF) {
711 			*last_err_str = "Link training failed, link is off";
712 			ret = -EIO;
713 			continue;
714 		}
715 
716 		break;
717 	}
718 
719 	/* If we saw quite a few retries, add a note about it */
720 	if (!ret && i > SN_LINK_TRAINING_TRIES / 2)
721 		DRM_DEV_INFO(pdata->dev, "Link training needed %d retries\n", i);
722 
723 exit:
724 	/* Disable the PLL if we failed */
725 	if (ret)
726 		regmap_write(pdata->regmap, SN_PLL_ENABLE_REG, 0);
727 
728 	return ret;
729 }
730 
731 static void ti_sn_bridge_enable(struct drm_bridge *bridge)
732 {
733 	struct ti_sn_bridge *pdata = bridge_to_ti_sn_bridge(bridge);
734 	bool rate_valid[ARRAY_SIZE(ti_sn_bridge_dp_rate_lut)] = { };
735 	const char *last_err_str = "No supported DP rate";
736 	int dp_rate_idx;
737 	unsigned int val;
738 	int ret = -EINVAL;
739 	int max_dp_lanes;
740 
741 	max_dp_lanes = ti_sn_get_max_lanes(pdata);
742 	pdata->dp_lanes = min(pdata->dp_lanes, max_dp_lanes);
743 
744 	/* DSI_A lane config */
745 	val = CHA_DSI_LANES(SN_MAX_DP_LANES - pdata->dsi->lanes);
746 	regmap_update_bits(pdata->regmap, SN_DSI_LANES_REG,
747 			   CHA_DSI_LANES_MASK, val);
748 
749 	regmap_write(pdata->regmap, SN_LN_ASSIGN_REG, pdata->ln_assign);
750 	regmap_update_bits(pdata->regmap, SN_ENH_FRAME_REG, LN_POLRS_MASK,
751 			   pdata->ln_polrs << LN_POLRS_OFFSET);
752 
753 	/* set dsi clk frequency value */
754 	ti_sn_bridge_set_dsi_rate(pdata);
755 
756 	/**
757 	 * The SN65DSI86 only supports ASSR Display Authentication method and
758 	 * this method is enabled by default. An eDP panel must support this
759 	 * authentication method. We need to enable this method in the eDP panel
760 	 * at DisplayPort address 0x0010A prior to link training.
761 	 */
762 	drm_dp_dpcd_writeb(&pdata->aux, DP_EDP_CONFIGURATION_SET,
763 			   DP_ALTERNATE_SCRAMBLER_RESET_ENABLE);
764 
765 	/* Set the DP output format (18 bpp or 24 bpp) */
766 	val = (ti_sn_bridge_get_bpp(pdata) == 18) ? BPP_18_RGB : 0;
767 	regmap_update_bits(pdata->regmap, SN_DATA_FORMAT_REG, BPP_18_RGB, val);
768 
769 	/* DP lane config */
770 	val = DP_NUM_LANES(min(pdata->dp_lanes, 3));
771 	regmap_update_bits(pdata->regmap, SN_SSC_CONFIG_REG, DP_NUM_LANES_MASK,
772 			   val);
773 
774 	ti_sn_bridge_read_valid_rates(pdata, rate_valid);
775 
776 	/* Train until we run out of rates */
777 	for (dp_rate_idx = ti_sn_bridge_calc_min_dp_rate_idx(pdata);
778 	     dp_rate_idx < ARRAY_SIZE(ti_sn_bridge_dp_rate_lut);
779 	     dp_rate_idx++) {
780 		if (!rate_valid[dp_rate_idx])
781 			continue;
782 
783 		ret = ti_sn_link_training(pdata, dp_rate_idx, &last_err_str);
784 		if (!ret)
785 			break;
786 	}
787 	if (ret) {
788 		DRM_DEV_ERROR(pdata->dev, "%s (%d)\n", last_err_str, ret);
789 		return;
790 	}
791 
792 	/* config video parameters */
793 	ti_sn_bridge_set_video_timings(pdata);
794 
795 	/* enable video stream */
796 	regmap_update_bits(pdata->regmap, SN_ENH_FRAME_REG, VSTREAM_ENABLE,
797 			   VSTREAM_ENABLE);
798 
799 	drm_panel_enable(pdata->panel);
800 }
801 
802 static void ti_sn_bridge_pre_enable(struct drm_bridge *bridge)
803 {
804 	struct ti_sn_bridge *pdata = bridge_to_ti_sn_bridge(bridge);
805 
806 	pm_runtime_get_sync(pdata->dev);
807 
808 	/* configure bridge ref_clk */
809 	ti_sn_bridge_set_refclk_freq(pdata);
810 
811 	/*
812 	 * HPD on this bridge chip is a bit useless.  This is an eDP bridge
813 	 * so the HPD is an internal signal that's only there to signal that
814 	 * the panel is done powering up.  ...but the bridge chip debounces
815 	 * this signal by between 100 ms and 400 ms (depending on process,
816 	 * voltage, and temperate--I measured it at about 200 ms).  One
817 	 * particular panel asserted HPD 84 ms after it was powered on meaning
818 	 * that we saw HPD 284 ms after power on.  ...but the same panel said
819 	 * that instead of looking at HPD you could just hardcode a delay of
820 	 * 200 ms.  We'll assume that the panel driver will have the hardcoded
821 	 * delay in its prepare and always disable HPD.
822 	 *
823 	 * If HPD somehow makes sense on some future panel we'll have to
824 	 * change this to be conditional on someone specifying that HPD should
825 	 * be used.
826 	 */
827 	regmap_update_bits(pdata->regmap, SN_HPD_DISABLE_REG, HPD_DISABLE,
828 			   HPD_DISABLE);
829 
830 	drm_panel_prepare(pdata->panel);
831 }
832 
833 static void ti_sn_bridge_post_disable(struct drm_bridge *bridge)
834 {
835 	struct ti_sn_bridge *pdata = bridge_to_ti_sn_bridge(bridge);
836 
837 	clk_disable_unprepare(pdata->refclk);
838 
839 	pm_runtime_put_sync(pdata->dev);
840 }
841 
842 static const struct drm_bridge_funcs ti_sn_bridge_funcs = {
843 	.attach = ti_sn_bridge_attach,
844 	.pre_enable = ti_sn_bridge_pre_enable,
845 	.enable = ti_sn_bridge_enable,
846 	.disable = ti_sn_bridge_disable,
847 	.post_disable = ti_sn_bridge_post_disable,
848 };
849 
850 static struct ti_sn_bridge *aux_to_ti_sn_bridge(struct drm_dp_aux *aux)
851 {
852 	return container_of(aux, struct ti_sn_bridge, aux);
853 }
854 
855 static ssize_t ti_sn_aux_transfer(struct drm_dp_aux *aux,
856 				  struct drm_dp_aux_msg *msg)
857 {
858 	struct ti_sn_bridge *pdata = aux_to_ti_sn_bridge(aux);
859 	u32 request = msg->request & ~DP_AUX_I2C_MOT;
860 	u32 request_val = AUX_CMD_REQ(msg->request);
861 	u8 *buf = (u8 *)msg->buffer;
862 	unsigned int val;
863 	int ret, i;
864 
865 	if (msg->size > SN_AUX_MAX_PAYLOAD_BYTES)
866 		return -EINVAL;
867 
868 	switch (request) {
869 	case DP_AUX_NATIVE_WRITE:
870 	case DP_AUX_I2C_WRITE:
871 	case DP_AUX_NATIVE_READ:
872 	case DP_AUX_I2C_READ:
873 		regmap_write(pdata->regmap, SN_AUX_CMD_REG, request_val);
874 		break;
875 	default:
876 		return -EINVAL;
877 	}
878 
879 	regmap_write(pdata->regmap, SN_AUX_ADDR_19_16_REG,
880 		     (msg->address >> 16) & 0xF);
881 	regmap_write(pdata->regmap, SN_AUX_ADDR_15_8_REG,
882 		     (msg->address >> 8) & 0xFF);
883 	regmap_write(pdata->regmap, SN_AUX_ADDR_7_0_REG, msg->address & 0xFF);
884 
885 	regmap_write(pdata->regmap, SN_AUX_LENGTH_REG, msg->size);
886 
887 	if (request == DP_AUX_NATIVE_WRITE || request == DP_AUX_I2C_WRITE) {
888 		for (i = 0; i < msg->size; i++)
889 			regmap_write(pdata->regmap, SN_AUX_WDATA_REG(i),
890 				     buf[i]);
891 	}
892 
893 	/* Clear old status bits before start so we don't get confused */
894 	regmap_write(pdata->regmap, SN_AUX_CMD_STATUS_REG,
895 		     AUX_IRQ_STATUS_NAT_I2C_FAIL |
896 		     AUX_IRQ_STATUS_AUX_RPLY_TOUT |
897 		     AUX_IRQ_STATUS_AUX_SHORT);
898 
899 	regmap_write(pdata->regmap, SN_AUX_CMD_REG, request_val | AUX_CMD_SEND);
900 
901 	ret = regmap_read_poll_timeout(pdata->regmap, SN_AUX_CMD_REG, val,
902 				       !(val & AUX_CMD_SEND), 200,
903 				       50 * 1000);
904 	if (ret)
905 		return ret;
906 
907 	ret = regmap_read(pdata->regmap, SN_AUX_CMD_STATUS_REG, &val);
908 	if (ret)
909 		return ret;
910 	else if ((val & AUX_IRQ_STATUS_NAT_I2C_FAIL)
911 		 || (val & AUX_IRQ_STATUS_AUX_RPLY_TOUT)
912 		 || (val & AUX_IRQ_STATUS_AUX_SHORT))
913 		return -ENXIO;
914 
915 	if (request == DP_AUX_NATIVE_WRITE || request == DP_AUX_I2C_WRITE)
916 		return msg->size;
917 
918 	for (i = 0; i < msg->size; i++) {
919 		unsigned int val;
920 		ret = regmap_read(pdata->regmap, SN_AUX_RDATA_REG(i),
921 				  &val);
922 		if (ret)
923 			return ret;
924 
925 		WARN_ON(val & ~0xFF);
926 		buf[i] = (u8)(val & 0xFF);
927 	}
928 
929 	return msg->size;
930 }
931 
932 static int ti_sn_bridge_parse_dsi_host(struct ti_sn_bridge *pdata)
933 {
934 	struct device_node *np = pdata->dev->of_node;
935 
936 	pdata->host_node = of_graph_get_remote_node(np, 0, 0);
937 
938 	if (!pdata->host_node) {
939 		DRM_ERROR("remote dsi host node not found\n");
940 		return -ENODEV;
941 	}
942 
943 	return 0;
944 }
945 
946 #if defined(CONFIG_OF_GPIO)
947 
948 static int tn_sn_bridge_of_xlate(struct gpio_chip *chip,
949 				 const struct of_phandle_args *gpiospec,
950 				 u32 *flags)
951 {
952 	if (WARN_ON(gpiospec->args_count < chip->of_gpio_n_cells))
953 		return -EINVAL;
954 
955 	if (gpiospec->args[0] > chip->ngpio || gpiospec->args[0] < 1)
956 		return -EINVAL;
957 
958 	if (flags)
959 		*flags = gpiospec->args[1];
960 
961 	return gpiospec->args[0] - SN_GPIO_PHYSICAL_OFFSET;
962 }
963 
964 static int ti_sn_bridge_gpio_get_direction(struct gpio_chip *chip,
965 					   unsigned int offset)
966 {
967 	struct ti_sn_bridge *pdata = gpiochip_get_data(chip);
968 
969 	/*
970 	 * We already have to keep track of the direction because we use
971 	 * that to figure out whether we've powered the device.  We can
972 	 * just return that rather than (maybe) powering up the device
973 	 * to ask its direction.
974 	 */
975 	return test_bit(offset, pdata->gchip_output) ?
976 		GPIO_LINE_DIRECTION_OUT : GPIO_LINE_DIRECTION_IN;
977 }
978 
979 static int ti_sn_bridge_gpio_get(struct gpio_chip *chip, unsigned int offset)
980 {
981 	struct ti_sn_bridge *pdata = gpiochip_get_data(chip);
982 	unsigned int val;
983 	int ret;
984 
985 	/*
986 	 * When the pin is an input we don't forcibly keep the bridge
987 	 * powered--we just power it on to read the pin.  NOTE: part of
988 	 * the reason this works is that the bridge defaults (when
989 	 * powered back on) to all 4 GPIOs being configured as GPIO input.
990 	 * Also note that if something else is keeping the chip powered the
991 	 * pm_runtime functions are lightweight increments of a refcount.
992 	 */
993 	pm_runtime_get_sync(pdata->dev);
994 	ret = regmap_read(pdata->regmap, SN_GPIO_IO_REG, &val);
995 	pm_runtime_put(pdata->dev);
996 
997 	if (ret)
998 		return ret;
999 
1000 	return !!(val & BIT(SN_GPIO_INPUT_SHIFT + offset));
1001 }
1002 
1003 static void ti_sn_bridge_gpio_set(struct gpio_chip *chip, unsigned int offset,
1004 				  int val)
1005 {
1006 	struct ti_sn_bridge *pdata = gpiochip_get_data(chip);
1007 	int ret;
1008 
1009 	if (!test_bit(offset, pdata->gchip_output)) {
1010 		dev_err(pdata->dev, "Ignoring GPIO set while input\n");
1011 		return;
1012 	}
1013 
1014 	val &= 1;
1015 	ret = regmap_update_bits(pdata->regmap, SN_GPIO_IO_REG,
1016 				 BIT(SN_GPIO_OUTPUT_SHIFT + offset),
1017 				 val << (SN_GPIO_OUTPUT_SHIFT + offset));
1018 	if (ret)
1019 		dev_warn(pdata->dev,
1020 			 "Failed to set bridge GPIO %u: %d\n", offset, ret);
1021 }
1022 
1023 static int ti_sn_bridge_gpio_direction_input(struct gpio_chip *chip,
1024 					     unsigned int offset)
1025 {
1026 	struct ti_sn_bridge *pdata = gpiochip_get_data(chip);
1027 	int shift = offset * 2;
1028 	int ret;
1029 
1030 	if (!test_and_clear_bit(offset, pdata->gchip_output))
1031 		return 0;
1032 
1033 	ret = regmap_update_bits(pdata->regmap, SN_GPIO_CTRL_REG,
1034 				 SN_GPIO_MUX_MASK << shift,
1035 				 SN_GPIO_MUX_INPUT << shift);
1036 	if (ret) {
1037 		set_bit(offset, pdata->gchip_output);
1038 		return ret;
1039 	}
1040 
1041 	/*
1042 	 * NOTE: if nobody else is powering the device this may fully power
1043 	 * it off and when it comes back it will have lost all state, but
1044 	 * that's OK because the default is input and we're now an input.
1045 	 */
1046 	pm_runtime_put(pdata->dev);
1047 
1048 	return 0;
1049 }
1050 
1051 static int ti_sn_bridge_gpio_direction_output(struct gpio_chip *chip,
1052 					      unsigned int offset, int val)
1053 {
1054 	struct ti_sn_bridge *pdata = gpiochip_get_data(chip);
1055 	int shift = offset * 2;
1056 	int ret;
1057 
1058 	if (test_and_set_bit(offset, pdata->gchip_output))
1059 		return 0;
1060 
1061 	pm_runtime_get_sync(pdata->dev);
1062 
1063 	/* Set value first to avoid glitching */
1064 	ti_sn_bridge_gpio_set(chip, offset, val);
1065 
1066 	/* Set direction */
1067 	ret = regmap_update_bits(pdata->regmap, SN_GPIO_CTRL_REG,
1068 				 SN_GPIO_MUX_MASK << shift,
1069 				 SN_GPIO_MUX_OUTPUT << shift);
1070 	if (ret) {
1071 		clear_bit(offset, pdata->gchip_output);
1072 		pm_runtime_put(pdata->dev);
1073 	}
1074 
1075 	return ret;
1076 }
1077 
1078 static void ti_sn_bridge_gpio_free(struct gpio_chip *chip, unsigned int offset)
1079 {
1080 	/* We won't keep pm_runtime if we're input, so switch there on free */
1081 	ti_sn_bridge_gpio_direction_input(chip, offset);
1082 }
1083 
1084 static const char * const ti_sn_bridge_gpio_names[SN_NUM_GPIOS] = {
1085 	"GPIO1", "GPIO2", "GPIO3", "GPIO4"
1086 };
1087 
1088 static int ti_sn_setup_gpio_controller(struct ti_sn_bridge *pdata)
1089 {
1090 	int ret;
1091 
1092 	/* Only init if someone is going to use us as a GPIO controller */
1093 	if (!of_property_read_bool(pdata->dev->of_node, "gpio-controller"))
1094 		return 0;
1095 
1096 	pdata->gchip.label = dev_name(pdata->dev);
1097 	pdata->gchip.parent = pdata->dev;
1098 	pdata->gchip.owner = THIS_MODULE;
1099 	pdata->gchip.of_xlate = tn_sn_bridge_of_xlate;
1100 	pdata->gchip.of_gpio_n_cells = 2;
1101 	pdata->gchip.free = ti_sn_bridge_gpio_free;
1102 	pdata->gchip.get_direction = ti_sn_bridge_gpio_get_direction;
1103 	pdata->gchip.direction_input = ti_sn_bridge_gpio_direction_input;
1104 	pdata->gchip.direction_output = ti_sn_bridge_gpio_direction_output;
1105 	pdata->gchip.get = ti_sn_bridge_gpio_get;
1106 	pdata->gchip.set = ti_sn_bridge_gpio_set;
1107 	pdata->gchip.can_sleep = true;
1108 	pdata->gchip.names = ti_sn_bridge_gpio_names;
1109 	pdata->gchip.ngpio = SN_NUM_GPIOS;
1110 	pdata->gchip.base = -1;
1111 	ret = devm_gpiochip_add_data(pdata->dev, &pdata->gchip, pdata);
1112 	if (ret)
1113 		dev_err(pdata->dev, "can't add gpio chip\n");
1114 
1115 	return ret;
1116 }
1117 
1118 #else
1119 
1120 static inline int ti_sn_setup_gpio_controller(struct ti_sn_bridge *pdata)
1121 {
1122 	return 0;
1123 }
1124 
1125 #endif
1126 
1127 static void ti_sn_bridge_parse_lanes(struct ti_sn_bridge *pdata,
1128 				     struct device_node *np)
1129 {
1130 	u32 lane_assignments[SN_MAX_DP_LANES] = { 0, 1, 2, 3 };
1131 	u32 lane_polarities[SN_MAX_DP_LANES] = { };
1132 	struct device_node *endpoint;
1133 	u8 ln_assign = 0;
1134 	u8 ln_polrs = 0;
1135 	int dp_lanes;
1136 	int i;
1137 
1138 	/*
1139 	 * Read config from the device tree about lane remapping and lane
1140 	 * polarities.  These are optional and we assume identity map and
1141 	 * normal polarity if nothing is specified.  It's OK to specify just
1142 	 * data-lanes but not lane-polarities but not vice versa.
1143 	 *
1144 	 * Error checking is light (we just make sure we don't crash or
1145 	 * buffer overrun) and we assume dts is well formed and specifying
1146 	 * mappings that the hardware supports.
1147 	 */
1148 	endpoint = of_graph_get_endpoint_by_regs(np, 1, -1);
1149 	dp_lanes = of_property_count_u32_elems(endpoint, "data-lanes");
1150 	if (dp_lanes > 0 && dp_lanes <= SN_MAX_DP_LANES) {
1151 		of_property_read_u32_array(endpoint, "data-lanes",
1152 					   lane_assignments, dp_lanes);
1153 		of_property_read_u32_array(endpoint, "lane-polarities",
1154 					   lane_polarities, dp_lanes);
1155 	} else {
1156 		dp_lanes = SN_MAX_DP_LANES;
1157 	}
1158 	of_node_put(endpoint);
1159 
1160 	/*
1161 	 * Convert into register format.  Loop over all lanes even if
1162 	 * data-lanes had fewer elements so that we nicely initialize
1163 	 * the LN_ASSIGN register.
1164 	 */
1165 	for (i = SN_MAX_DP_LANES - 1; i >= 0; i--) {
1166 		ln_assign = ln_assign << LN_ASSIGN_WIDTH | lane_assignments[i];
1167 		ln_polrs = ln_polrs << 1 | lane_polarities[i];
1168 	}
1169 
1170 	/* Stash in our struct for when we power on */
1171 	pdata->dp_lanes = dp_lanes;
1172 	pdata->ln_assign = ln_assign;
1173 	pdata->ln_polrs = ln_polrs;
1174 }
1175 
1176 static int ti_sn_bridge_probe(struct i2c_client *client,
1177 			      const struct i2c_device_id *id)
1178 {
1179 	struct ti_sn_bridge *pdata;
1180 	int ret;
1181 
1182 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
1183 		DRM_ERROR("device doesn't support I2C\n");
1184 		return -ENODEV;
1185 	}
1186 
1187 	pdata = devm_kzalloc(&client->dev, sizeof(struct ti_sn_bridge),
1188 			     GFP_KERNEL);
1189 	if (!pdata)
1190 		return -ENOMEM;
1191 
1192 	pdata->regmap = devm_regmap_init_i2c(client,
1193 					     &ti_sn_bridge_regmap_config);
1194 	if (IS_ERR(pdata->regmap)) {
1195 		DRM_ERROR("regmap i2c init failed\n");
1196 		return PTR_ERR(pdata->regmap);
1197 	}
1198 
1199 	pdata->dev = &client->dev;
1200 
1201 	ret = drm_of_find_panel_or_bridge(pdata->dev->of_node, 1, 0,
1202 					  &pdata->panel, NULL);
1203 	if (ret) {
1204 		DRM_ERROR("could not find any panel node\n");
1205 		return ret;
1206 	}
1207 
1208 	dev_set_drvdata(&client->dev, pdata);
1209 
1210 	pdata->enable_gpio = devm_gpiod_get(pdata->dev, "enable",
1211 					    GPIOD_OUT_LOW);
1212 	if (IS_ERR(pdata->enable_gpio)) {
1213 		DRM_ERROR("failed to get enable gpio from DT\n");
1214 		ret = PTR_ERR(pdata->enable_gpio);
1215 		return ret;
1216 	}
1217 
1218 	ti_sn_bridge_parse_lanes(pdata, client->dev.of_node);
1219 
1220 	ret = ti_sn_bridge_parse_regulators(pdata);
1221 	if (ret) {
1222 		DRM_ERROR("failed to parse regulators\n");
1223 		return ret;
1224 	}
1225 
1226 	pdata->refclk = devm_clk_get(pdata->dev, "refclk");
1227 	if (IS_ERR(pdata->refclk)) {
1228 		ret = PTR_ERR(pdata->refclk);
1229 		if (ret == -EPROBE_DEFER)
1230 			return ret;
1231 		DRM_DEBUG_KMS("refclk not found\n");
1232 		pdata->refclk = NULL;
1233 	}
1234 
1235 	ret = ti_sn_bridge_parse_dsi_host(pdata);
1236 	if (ret)
1237 		return ret;
1238 
1239 	pm_runtime_enable(pdata->dev);
1240 
1241 	ret = ti_sn_setup_gpio_controller(pdata);
1242 	if (ret) {
1243 		pm_runtime_disable(pdata->dev);
1244 		return ret;
1245 	}
1246 
1247 	i2c_set_clientdata(client, pdata);
1248 
1249 	pdata->aux.name = "ti-sn65dsi86-aux";
1250 	pdata->aux.dev = pdata->dev;
1251 	pdata->aux.transfer = ti_sn_aux_transfer;
1252 	drm_dp_aux_register(&pdata->aux);
1253 
1254 	pdata->bridge.funcs = &ti_sn_bridge_funcs;
1255 	pdata->bridge.of_node = client->dev.of_node;
1256 
1257 	drm_bridge_add(&pdata->bridge);
1258 
1259 	ti_sn_debugfs_init(pdata);
1260 
1261 	return 0;
1262 }
1263 
1264 static int ti_sn_bridge_remove(struct i2c_client *client)
1265 {
1266 	struct ti_sn_bridge *pdata = i2c_get_clientdata(client);
1267 
1268 	if (!pdata)
1269 		return -EINVAL;
1270 
1271 	ti_sn_debugfs_remove(pdata);
1272 
1273 	of_node_put(pdata->host_node);
1274 
1275 	pm_runtime_disable(pdata->dev);
1276 
1277 	if (pdata->dsi) {
1278 		mipi_dsi_detach(pdata->dsi);
1279 		mipi_dsi_device_unregister(pdata->dsi);
1280 	}
1281 
1282 	drm_bridge_remove(&pdata->bridge);
1283 
1284 	return 0;
1285 }
1286 
1287 static struct i2c_device_id ti_sn_bridge_id[] = {
1288 	{ "ti,sn65dsi86", 0},
1289 	{},
1290 };
1291 MODULE_DEVICE_TABLE(i2c, ti_sn_bridge_id);
1292 
1293 static const struct of_device_id ti_sn_bridge_match_table[] = {
1294 	{.compatible = "ti,sn65dsi86"},
1295 	{},
1296 };
1297 MODULE_DEVICE_TABLE(of, ti_sn_bridge_match_table);
1298 
1299 static struct i2c_driver ti_sn_bridge_driver = {
1300 	.driver = {
1301 		.name = "ti_sn65dsi86",
1302 		.of_match_table = ti_sn_bridge_match_table,
1303 		.pm = &ti_sn_bridge_pm_ops,
1304 	},
1305 	.probe = ti_sn_bridge_probe,
1306 	.remove = ti_sn_bridge_remove,
1307 	.id_table = ti_sn_bridge_id,
1308 };
1309 module_i2c_driver(ti_sn_bridge_driver);
1310 
1311 MODULE_AUTHOR("Sandeep Panda <spanda@codeaurora.org>");
1312 MODULE_DESCRIPTION("sn65dsi86 DSI to eDP bridge driver");
1313 MODULE_LICENSE("GPL v2");
1314