1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (c) 2018, The Linux Foundation. All rights reserved.
4  * datasheet: http://www.ti.com/lit/ds/symlink/sn65dsi86.pdf
5  */
6 
7 #include <linux/clk.h>
8 #include <linux/debugfs.h>
9 #include <linux/gpio/consumer.h>
10 #include <linux/i2c.h>
11 #include <linux/iopoll.h>
12 #include <linux/module.h>
13 #include <linux/of_graph.h>
14 #include <linux/pm_runtime.h>
15 #include <linux/regmap.h>
16 #include <linux/regulator/consumer.h>
17 
18 #include <drm/drm_atomic.h>
19 #include <drm/drm_atomic_helper.h>
20 #include <drm/drm_dp_helper.h>
21 #include <drm/drm_mipi_dsi.h>
22 #include <drm/drm_of.h>
23 #include <drm/drm_panel.h>
24 #include <drm/drm_print.h>
25 #include <drm/drm_probe_helper.h>
26 
27 #define SN_DEVICE_REV_REG			0x08
28 #define SN_DPPLL_SRC_REG			0x0A
29 #define  DPPLL_CLK_SRC_DSICLK			BIT(0)
30 #define  REFCLK_FREQ_MASK			GENMASK(3, 1)
31 #define  REFCLK_FREQ(x)				((x) << 1)
32 #define  DPPLL_SRC_DP_PLL_LOCK			BIT(7)
33 #define SN_PLL_ENABLE_REG			0x0D
34 #define SN_DSI_LANES_REG			0x10
35 #define  CHA_DSI_LANES_MASK			GENMASK(4, 3)
36 #define  CHA_DSI_LANES(x)			((x) << 3)
37 #define SN_DSIA_CLK_FREQ_REG			0x12
38 #define SN_CHA_ACTIVE_LINE_LENGTH_LOW_REG	0x20
39 #define SN_CHA_VERTICAL_DISPLAY_SIZE_LOW_REG	0x24
40 #define SN_CHA_HSYNC_PULSE_WIDTH_LOW_REG	0x2C
41 #define SN_CHA_HSYNC_PULSE_WIDTH_HIGH_REG	0x2D
42 #define  CHA_HSYNC_POLARITY			BIT(7)
43 #define SN_CHA_VSYNC_PULSE_WIDTH_LOW_REG	0x30
44 #define SN_CHA_VSYNC_PULSE_WIDTH_HIGH_REG	0x31
45 #define  CHA_VSYNC_POLARITY			BIT(7)
46 #define SN_CHA_HORIZONTAL_BACK_PORCH_REG	0x34
47 #define SN_CHA_VERTICAL_BACK_PORCH_REG		0x36
48 #define SN_CHA_HORIZONTAL_FRONT_PORCH_REG	0x38
49 #define SN_CHA_VERTICAL_FRONT_PORCH_REG		0x3A
50 #define SN_ENH_FRAME_REG			0x5A
51 #define  VSTREAM_ENABLE				BIT(3)
52 #define SN_DATA_FORMAT_REG			0x5B
53 #define SN_HPD_DISABLE_REG			0x5C
54 #define  HPD_DISABLE				BIT(0)
55 #define SN_AUX_WDATA_REG(x)			(0x64 + (x))
56 #define SN_AUX_ADDR_19_16_REG			0x74
57 #define SN_AUX_ADDR_15_8_REG			0x75
58 #define SN_AUX_ADDR_7_0_REG			0x76
59 #define SN_AUX_LENGTH_REG			0x77
60 #define SN_AUX_CMD_REG				0x78
61 #define  AUX_CMD_SEND				BIT(0)
62 #define  AUX_CMD_REQ(x)				((x) << 4)
63 #define SN_AUX_RDATA_REG(x)			(0x79 + (x))
64 #define SN_SSC_CONFIG_REG			0x93
65 #define  DP_NUM_LANES_MASK			GENMASK(5, 4)
66 #define  DP_NUM_LANES(x)			((x) << 4)
67 #define SN_DATARATE_CONFIG_REG			0x94
68 #define  DP_DATARATE_MASK			GENMASK(7, 5)
69 #define  DP_DATARATE(x)				((x) << 5)
70 #define SN_ML_TX_MODE_REG			0x96
71 #define  ML_TX_MAIN_LINK_OFF			0
72 #define  ML_TX_NORMAL_MODE			BIT(0)
73 #define SN_AUX_CMD_STATUS_REG			0xF4
74 #define  AUX_IRQ_STATUS_AUX_RPLY_TOUT		BIT(3)
75 #define  AUX_IRQ_STATUS_AUX_SHORT		BIT(5)
76 #define  AUX_IRQ_STATUS_NAT_I2C_FAIL		BIT(6)
77 
78 #define MIN_DSI_CLK_FREQ_MHZ	40
79 
80 /* fudge factor required to account for 8b/10b encoding */
81 #define DP_CLK_FUDGE_NUM	10
82 #define DP_CLK_FUDGE_DEN	8
83 
84 /* Matches DP_AUX_MAX_PAYLOAD_BYTES (for now) */
85 #define SN_AUX_MAX_PAYLOAD_BYTES	16
86 
87 #define SN_REGULATOR_SUPPLY_NUM		4
88 
89 struct ti_sn_bridge {
90 	struct device			*dev;
91 	struct regmap			*regmap;
92 	struct drm_dp_aux		aux;
93 	struct drm_bridge		bridge;
94 	struct drm_connector		connector;
95 	struct dentry			*debugfs;
96 	struct device_node		*host_node;
97 	struct mipi_dsi_device		*dsi;
98 	struct clk			*refclk;
99 	struct drm_panel		*panel;
100 	struct gpio_desc		*enable_gpio;
101 	struct regulator_bulk_data	supplies[SN_REGULATOR_SUPPLY_NUM];
102 };
103 
104 static const struct regmap_range ti_sn_bridge_volatile_ranges[] = {
105 	{ .range_min = 0, .range_max = 0xFF },
106 };
107 
108 static const struct regmap_access_table ti_sn_bridge_volatile_table = {
109 	.yes_ranges = ti_sn_bridge_volatile_ranges,
110 	.n_yes_ranges = ARRAY_SIZE(ti_sn_bridge_volatile_ranges),
111 };
112 
113 static const struct regmap_config ti_sn_bridge_regmap_config = {
114 	.reg_bits = 8,
115 	.val_bits = 8,
116 	.volatile_table = &ti_sn_bridge_volatile_table,
117 	.cache_type = REGCACHE_NONE,
118 };
119 
120 static void ti_sn_bridge_write_u16(struct ti_sn_bridge *pdata,
121 				   unsigned int reg, u16 val)
122 {
123 	regmap_write(pdata->regmap, reg, val & 0xFF);
124 	regmap_write(pdata->regmap, reg + 1, val >> 8);
125 }
126 
127 static int __maybe_unused ti_sn_bridge_resume(struct device *dev)
128 {
129 	struct ti_sn_bridge *pdata = dev_get_drvdata(dev);
130 	int ret;
131 
132 	ret = regulator_bulk_enable(SN_REGULATOR_SUPPLY_NUM, pdata->supplies);
133 	if (ret) {
134 		DRM_ERROR("failed to enable supplies %d\n", ret);
135 		return ret;
136 	}
137 
138 	gpiod_set_value(pdata->enable_gpio, 1);
139 
140 	return ret;
141 }
142 
143 static int __maybe_unused ti_sn_bridge_suspend(struct device *dev)
144 {
145 	struct ti_sn_bridge *pdata = dev_get_drvdata(dev);
146 	int ret;
147 
148 	gpiod_set_value(pdata->enable_gpio, 0);
149 
150 	ret = regulator_bulk_disable(SN_REGULATOR_SUPPLY_NUM, pdata->supplies);
151 	if (ret)
152 		DRM_ERROR("failed to disable supplies %d\n", ret);
153 
154 	return ret;
155 }
156 
157 static const struct dev_pm_ops ti_sn_bridge_pm_ops = {
158 	SET_RUNTIME_PM_OPS(ti_sn_bridge_suspend, ti_sn_bridge_resume, NULL)
159 };
160 
161 static int status_show(struct seq_file *s, void *data)
162 {
163 	struct ti_sn_bridge *pdata = s->private;
164 	unsigned int reg, val;
165 
166 	seq_puts(s, "STATUS REGISTERS:\n");
167 
168 	pm_runtime_get_sync(pdata->dev);
169 
170 	/* IRQ Status Registers, see Table 31 in datasheet */
171 	for (reg = 0xf0; reg <= 0xf8; reg++) {
172 		regmap_read(pdata->regmap, reg, &val);
173 		seq_printf(s, "[0x%02x] = 0x%08x\n", reg, val);
174 	}
175 
176 	pm_runtime_put(pdata->dev);
177 
178 	return 0;
179 }
180 
181 DEFINE_SHOW_ATTRIBUTE(status);
182 
183 static void ti_sn_debugfs_init(struct ti_sn_bridge *pdata)
184 {
185 	pdata->debugfs = debugfs_create_dir(dev_name(pdata->dev), NULL);
186 
187 	debugfs_create_file("status", 0600, pdata->debugfs, pdata,
188 			&status_fops);
189 }
190 
191 static void ti_sn_debugfs_remove(struct ti_sn_bridge *pdata)
192 {
193 	debugfs_remove_recursive(pdata->debugfs);
194 	pdata->debugfs = NULL;
195 }
196 
197 /* Connector funcs */
198 static struct ti_sn_bridge *
199 connector_to_ti_sn_bridge(struct drm_connector *connector)
200 {
201 	return container_of(connector, struct ti_sn_bridge, connector);
202 }
203 
204 static int ti_sn_bridge_connector_get_modes(struct drm_connector *connector)
205 {
206 	struct ti_sn_bridge *pdata = connector_to_ti_sn_bridge(connector);
207 
208 	return drm_panel_get_modes(pdata->panel);
209 }
210 
211 static enum drm_mode_status
212 ti_sn_bridge_connector_mode_valid(struct drm_connector *connector,
213 				  struct drm_display_mode *mode)
214 {
215 	/* maximum supported resolution is 4K at 60 fps */
216 	if (mode->clock > 594000)
217 		return MODE_CLOCK_HIGH;
218 
219 	return MODE_OK;
220 }
221 
222 static struct drm_connector_helper_funcs ti_sn_bridge_connector_helper_funcs = {
223 	.get_modes = ti_sn_bridge_connector_get_modes,
224 	.mode_valid = ti_sn_bridge_connector_mode_valid,
225 };
226 
227 static enum drm_connector_status
228 ti_sn_bridge_connector_detect(struct drm_connector *connector, bool force)
229 {
230 	/**
231 	 * TODO: Currently if drm_panel is present, then always
232 	 * return the status as connected. Need to add support to detect
233 	 * device state for hot pluggable scenarios.
234 	 */
235 	return connector_status_connected;
236 }
237 
238 static const struct drm_connector_funcs ti_sn_bridge_connector_funcs = {
239 	.fill_modes = drm_helper_probe_single_connector_modes,
240 	.detect = ti_sn_bridge_connector_detect,
241 	.destroy = drm_connector_cleanup,
242 	.reset = drm_atomic_helper_connector_reset,
243 	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
244 	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
245 };
246 
247 static struct ti_sn_bridge *bridge_to_ti_sn_bridge(struct drm_bridge *bridge)
248 {
249 	return container_of(bridge, struct ti_sn_bridge, bridge);
250 }
251 
252 static int ti_sn_bridge_parse_regulators(struct ti_sn_bridge *pdata)
253 {
254 	unsigned int i;
255 	const char * const ti_sn_bridge_supply_names[] = {
256 		"vcca", "vcc", "vccio", "vpll",
257 	};
258 
259 	for (i = 0; i < SN_REGULATOR_SUPPLY_NUM; i++)
260 		pdata->supplies[i].supply = ti_sn_bridge_supply_names[i];
261 
262 	return devm_regulator_bulk_get(pdata->dev, SN_REGULATOR_SUPPLY_NUM,
263 				       pdata->supplies);
264 }
265 
266 static int ti_sn_bridge_attach(struct drm_bridge *bridge)
267 {
268 	int ret, val;
269 	struct ti_sn_bridge *pdata = bridge_to_ti_sn_bridge(bridge);
270 	struct mipi_dsi_host *host;
271 	struct mipi_dsi_device *dsi;
272 	const struct mipi_dsi_device_info info = { .type = "ti_sn_bridge",
273 						   .channel = 0,
274 						   .node = NULL,
275 						 };
276 
277 	ret = drm_connector_init(bridge->dev, &pdata->connector,
278 				 &ti_sn_bridge_connector_funcs,
279 				 DRM_MODE_CONNECTOR_eDP);
280 	if (ret) {
281 		DRM_ERROR("Failed to initialize connector with drm\n");
282 		return ret;
283 	}
284 
285 	drm_connector_helper_add(&pdata->connector,
286 				 &ti_sn_bridge_connector_helper_funcs);
287 	drm_connector_attach_encoder(&pdata->connector, bridge->encoder);
288 
289 	/*
290 	 * TODO: ideally finding host resource and dsi dev registration needs
291 	 * to be done in bridge probe. But some existing DSI host drivers will
292 	 * wait for any of the drm_bridge/drm_panel to get added to the global
293 	 * bridge/panel list, before completing their probe. So if we do the
294 	 * dsi dev registration part in bridge probe, before populating in
295 	 * the global bridge list, then it will cause deadlock as dsi host probe
296 	 * will never complete, neither our bridge probe. So keeping it here
297 	 * will satisfy most of the existing host drivers. Once the host driver
298 	 * is fixed we can move the below code to bridge probe safely.
299 	 */
300 	host = of_find_mipi_dsi_host_by_node(pdata->host_node);
301 	if (!host) {
302 		DRM_ERROR("failed to find dsi host\n");
303 		ret = -ENODEV;
304 		goto err_dsi_host;
305 	}
306 
307 	dsi = mipi_dsi_device_register_full(host, &info);
308 	if (IS_ERR(dsi)) {
309 		DRM_ERROR("failed to create dsi device\n");
310 		ret = PTR_ERR(dsi);
311 		goto err_dsi_host;
312 	}
313 
314 	/* TODO: setting to 4 lanes always for now */
315 	dsi->lanes = 4;
316 	dsi->format = MIPI_DSI_FMT_RGB888;
317 	dsi->mode_flags = MIPI_DSI_MODE_VIDEO;
318 
319 	/* check if continuous dsi clock is required or not */
320 	pm_runtime_get_sync(pdata->dev);
321 	regmap_read(pdata->regmap, SN_DPPLL_SRC_REG, &val);
322 	pm_runtime_put(pdata->dev);
323 	if (!(val & DPPLL_CLK_SRC_DSICLK))
324 		dsi->mode_flags |= MIPI_DSI_CLOCK_NON_CONTINUOUS;
325 
326 	ret = mipi_dsi_attach(dsi);
327 	if (ret < 0) {
328 		DRM_ERROR("failed to attach dsi to host\n");
329 		goto err_dsi_attach;
330 	}
331 	pdata->dsi = dsi;
332 
333 	/* attach panel to bridge */
334 	drm_panel_attach(pdata->panel, &pdata->connector);
335 
336 	return 0;
337 
338 err_dsi_attach:
339 	mipi_dsi_device_unregister(dsi);
340 err_dsi_host:
341 	drm_connector_cleanup(&pdata->connector);
342 	return ret;
343 }
344 
345 static void ti_sn_bridge_disable(struct drm_bridge *bridge)
346 {
347 	struct ti_sn_bridge *pdata = bridge_to_ti_sn_bridge(bridge);
348 
349 	drm_panel_disable(pdata->panel);
350 
351 	/* disable video stream */
352 	regmap_update_bits(pdata->regmap, SN_ENH_FRAME_REG, VSTREAM_ENABLE, 0);
353 	/* semi auto link training mode OFF */
354 	regmap_write(pdata->regmap, SN_ML_TX_MODE_REG, 0);
355 	/* disable DP PLL */
356 	regmap_write(pdata->regmap, SN_PLL_ENABLE_REG, 0);
357 
358 	drm_panel_unprepare(pdata->panel);
359 }
360 
361 static u32 ti_sn_bridge_get_dsi_freq(struct ti_sn_bridge *pdata)
362 {
363 	u32 bit_rate_khz, clk_freq_khz;
364 	struct drm_display_mode *mode =
365 		&pdata->bridge.encoder->crtc->state->adjusted_mode;
366 
367 	bit_rate_khz = mode->clock *
368 			mipi_dsi_pixel_format_to_bpp(pdata->dsi->format);
369 	clk_freq_khz = bit_rate_khz / (pdata->dsi->lanes * 2);
370 
371 	return clk_freq_khz;
372 }
373 
374 /* clk frequencies supported by bridge in Hz in case derived from REFCLK pin */
375 static const u32 ti_sn_bridge_refclk_lut[] = {
376 	12000000,
377 	19200000,
378 	26000000,
379 	27000000,
380 	38400000,
381 };
382 
383 /* clk frequencies supported by bridge in Hz in case derived from DACP/N pin */
384 static const u32 ti_sn_bridge_dsiclk_lut[] = {
385 	468000000,
386 	384000000,
387 	416000000,
388 	486000000,
389 	460800000,
390 };
391 
392 static void ti_sn_bridge_set_refclk_freq(struct ti_sn_bridge *pdata)
393 {
394 	int i;
395 	u32 refclk_rate;
396 	const u32 *refclk_lut;
397 	size_t refclk_lut_size;
398 
399 	if (pdata->refclk) {
400 		refclk_rate = clk_get_rate(pdata->refclk);
401 		refclk_lut = ti_sn_bridge_refclk_lut;
402 		refclk_lut_size = ARRAY_SIZE(ti_sn_bridge_refclk_lut);
403 		clk_prepare_enable(pdata->refclk);
404 	} else {
405 		refclk_rate = ti_sn_bridge_get_dsi_freq(pdata) * 1000;
406 		refclk_lut = ti_sn_bridge_dsiclk_lut;
407 		refclk_lut_size = ARRAY_SIZE(ti_sn_bridge_dsiclk_lut);
408 	}
409 
410 	/* for i equals to refclk_lut_size means default frequency */
411 	for (i = 0; i < refclk_lut_size; i++)
412 		if (refclk_lut[i] == refclk_rate)
413 			break;
414 
415 	regmap_update_bits(pdata->regmap, SN_DPPLL_SRC_REG, REFCLK_FREQ_MASK,
416 			   REFCLK_FREQ(i));
417 }
418 
419 /**
420  * LUT index corresponds to register value and
421  * LUT values corresponds to dp data rate supported
422  * by the bridge in Mbps unit.
423  */
424 static const unsigned int ti_sn_bridge_dp_rate_lut[] = {
425 	0, 1620, 2160, 2430, 2700, 3240, 4320, 5400
426 };
427 
428 static void ti_sn_bridge_set_dsi_dp_rate(struct ti_sn_bridge *pdata)
429 {
430 	unsigned int bit_rate_mhz, clk_freq_mhz, dp_rate_mhz;
431 	unsigned int val, i;
432 	struct drm_display_mode *mode =
433 		&pdata->bridge.encoder->crtc->state->adjusted_mode;
434 
435 	/* set DSIA clk frequency */
436 	bit_rate_mhz = (mode->clock / 1000) *
437 			mipi_dsi_pixel_format_to_bpp(pdata->dsi->format);
438 	clk_freq_mhz = bit_rate_mhz / (pdata->dsi->lanes * 2);
439 
440 	/* for each increment in val, frequency increases by 5MHz */
441 	val = (MIN_DSI_CLK_FREQ_MHZ / 5) +
442 		(((clk_freq_mhz - MIN_DSI_CLK_FREQ_MHZ) / 5) & 0xFF);
443 	regmap_write(pdata->regmap, SN_DSIA_CLK_FREQ_REG, val);
444 
445 	/* set DP data rate */
446 	dp_rate_mhz = ((bit_rate_mhz / pdata->dsi->lanes) * DP_CLK_FUDGE_NUM) /
447 							DP_CLK_FUDGE_DEN;
448 	for (i = 0; i < ARRAY_SIZE(ti_sn_bridge_dp_rate_lut) - 1; i++)
449 		if (ti_sn_bridge_dp_rate_lut[i] > dp_rate_mhz)
450 			break;
451 
452 	regmap_update_bits(pdata->regmap, SN_DATARATE_CONFIG_REG,
453 			   DP_DATARATE_MASK, DP_DATARATE(i));
454 }
455 
456 static void ti_sn_bridge_set_video_timings(struct ti_sn_bridge *pdata)
457 {
458 	struct drm_display_mode *mode =
459 		&pdata->bridge.encoder->crtc->state->adjusted_mode;
460 	u8 hsync_polarity = 0, vsync_polarity = 0;
461 
462 	if (mode->flags & DRM_MODE_FLAG_PHSYNC)
463 		hsync_polarity = CHA_HSYNC_POLARITY;
464 	if (mode->flags & DRM_MODE_FLAG_PVSYNC)
465 		vsync_polarity = CHA_VSYNC_POLARITY;
466 
467 	ti_sn_bridge_write_u16(pdata, SN_CHA_ACTIVE_LINE_LENGTH_LOW_REG,
468 			       mode->hdisplay);
469 	ti_sn_bridge_write_u16(pdata, SN_CHA_VERTICAL_DISPLAY_SIZE_LOW_REG,
470 			       mode->vdisplay);
471 	regmap_write(pdata->regmap, SN_CHA_HSYNC_PULSE_WIDTH_LOW_REG,
472 		     (mode->hsync_end - mode->hsync_start) & 0xFF);
473 	regmap_write(pdata->regmap, SN_CHA_HSYNC_PULSE_WIDTH_HIGH_REG,
474 		     (((mode->hsync_end - mode->hsync_start) >> 8) & 0x7F) |
475 		     hsync_polarity);
476 	regmap_write(pdata->regmap, SN_CHA_VSYNC_PULSE_WIDTH_LOW_REG,
477 		     (mode->vsync_end - mode->vsync_start) & 0xFF);
478 	regmap_write(pdata->regmap, SN_CHA_VSYNC_PULSE_WIDTH_HIGH_REG,
479 		     (((mode->vsync_end - mode->vsync_start) >> 8) & 0x7F) |
480 		     vsync_polarity);
481 
482 	regmap_write(pdata->regmap, SN_CHA_HORIZONTAL_BACK_PORCH_REG,
483 		     (mode->htotal - mode->hsync_end) & 0xFF);
484 	regmap_write(pdata->regmap, SN_CHA_VERTICAL_BACK_PORCH_REG,
485 		     (mode->vtotal - mode->vsync_end) & 0xFF);
486 
487 	regmap_write(pdata->regmap, SN_CHA_HORIZONTAL_FRONT_PORCH_REG,
488 		     (mode->hsync_start - mode->hdisplay) & 0xFF);
489 	regmap_write(pdata->regmap, SN_CHA_VERTICAL_FRONT_PORCH_REG,
490 		     (mode->vsync_start - mode->vdisplay) & 0xFF);
491 
492 	usleep_range(10000, 10500); /* 10ms delay recommended by spec */
493 }
494 
495 static void ti_sn_bridge_enable(struct drm_bridge *bridge)
496 {
497 	struct ti_sn_bridge *pdata = bridge_to_ti_sn_bridge(bridge);
498 	unsigned int val;
499 	int ret;
500 
501 	/* DSI_A lane config */
502 	val = CHA_DSI_LANES(4 - pdata->dsi->lanes);
503 	regmap_update_bits(pdata->regmap, SN_DSI_LANES_REG,
504 			   CHA_DSI_LANES_MASK, val);
505 
506 	/* DP lane config */
507 	val = DP_NUM_LANES(pdata->dsi->lanes - 1);
508 	regmap_update_bits(pdata->regmap, SN_SSC_CONFIG_REG, DP_NUM_LANES_MASK,
509 			   val);
510 
511 	/* set dsi/dp clk frequency value */
512 	ti_sn_bridge_set_dsi_dp_rate(pdata);
513 
514 	/* enable DP PLL */
515 	regmap_write(pdata->regmap, SN_PLL_ENABLE_REG, 1);
516 
517 	ret = regmap_read_poll_timeout(pdata->regmap, SN_DPPLL_SRC_REG, val,
518 				       val & DPPLL_SRC_DP_PLL_LOCK, 1000,
519 				       50 * 1000);
520 	if (ret) {
521 		DRM_ERROR("DP_PLL_LOCK polling failed (%d)\n", ret);
522 		return;
523 	}
524 
525 	/**
526 	 * The SN65DSI86 only supports ASSR Display Authentication method and
527 	 * this method is enabled by default. An eDP panel must support this
528 	 * authentication method. We need to enable this method in the eDP panel
529 	 * at DisplayPort address 0x0010A prior to link training.
530 	 */
531 	drm_dp_dpcd_writeb(&pdata->aux, DP_EDP_CONFIGURATION_SET,
532 			   DP_ALTERNATE_SCRAMBLER_RESET_ENABLE);
533 
534 	/* Semi auto link training mode */
535 	regmap_write(pdata->regmap, SN_ML_TX_MODE_REG, 0x0A);
536 	ret = regmap_read_poll_timeout(pdata->regmap, SN_ML_TX_MODE_REG, val,
537 				       val == ML_TX_MAIN_LINK_OFF ||
538 				       val == ML_TX_NORMAL_MODE, 1000,
539 				       500 * 1000);
540 	if (ret) {
541 		DRM_ERROR("Training complete polling failed (%d)\n", ret);
542 		return;
543 	} else if (val == ML_TX_MAIN_LINK_OFF) {
544 		DRM_ERROR("Link training failed, link is off\n");
545 		return;
546 	}
547 
548 	/* config video parameters */
549 	ti_sn_bridge_set_video_timings(pdata);
550 
551 	/* enable video stream */
552 	regmap_update_bits(pdata->regmap, SN_ENH_FRAME_REG, VSTREAM_ENABLE,
553 			   VSTREAM_ENABLE);
554 
555 	drm_panel_enable(pdata->panel);
556 }
557 
558 static void ti_sn_bridge_pre_enable(struct drm_bridge *bridge)
559 {
560 	struct ti_sn_bridge *pdata = bridge_to_ti_sn_bridge(bridge);
561 
562 	pm_runtime_get_sync(pdata->dev);
563 
564 	/* configure bridge ref_clk */
565 	ti_sn_bridge_set_refclk_freq(pdata);
566 
567 	/*
568 	 * HPD on this bridge chip is a bit useless.  This is an eDP bridge
569 	 * so the HPD is an internal signal that's only there to signal that
570 	 * the panel is done powering up.  ...but the bridge chip debounces
571 	 * this signal by between 100 ms and 400 ms (depending on process,
572 	 * voltage, and temperate--I measured it at about 200 ms).  One
573 	 * particular panel asserted HPD 84 ms after it was powered on meaning
574 	 * that we saw HPD 284 ms after power on.  ...but the same panel said
575 	 * that instead of looking at HPD you could just hardcode a delay of
576 	 * 200 ms.  We'll assume that the panel driver will have the hardcoded
577 	 * delay in its prepare and always disable HPD.
578 	 *
579 	 * If HPD somehow makes sense on some future panel we'll have to
580 	 * change this to be conditional on someone specifying that HPD should
581 	 * be used.
582 	 */
583 	regmap_update_bits(pdata->regmap, SN_HPD_DISABLE_REG, HPD_DISABLE,
584 			   HPD_DISABLE);
585 
586 	drm_panel_prepare(pdata->panel);
587 }
588 
589 static void ti_sn_bridge_post_disable(struct drm_bridge *bridge)
590 {
591 	struct ti_sn_bridge *pdata = bridge_to_ti_sn_bridge(bridge);
592 
593 	if (pdata->refclk)
594 		clk_disable_unprepare(pdata->refclk);
595 
596 	pm_runtime_put_sync(pdata->dev);
597 }
598 
599 static const struct drm_bridge_funcs ti_sn_bridge_funcs = {
600 	.attach = ti_sn_bridge_attach,
601 	.pre_enable = ti_sn_bridge_pre_enable,
602 	.enable = ti_sn_bridge_enable,
603 	.disable = ti_sn_bridge_disable,
604 	.post_disable = ti_sn_bridge_post_disable,
605 };
606 
607 static struct ti_sn_bridge *aux_to_ti_sn_bridge(struct drm_dp_aux *aux)
608 {
609 	return container_of(aux, struct ti_sn_bridge, aux);
610 }
611 
612 static ssize_t ti_sn_aux_transfer(struct drm_dp_aux *aux,
613 				  struct drm_dp_aux_msg *msg)
614 {
615 	struct ti_sn_bridge *pdata = aux_to_ti_sn_bridge(aux);
616 	u32 request = msg->request & ~DP_AUX_I2C_MOT;
617 	u32 request_val = AUX_CMD_REQ(msg->request);
618 	u8 *buf = (u8 *)msg->buffer;
619 	unsigned int val;
620 	int ret, i;
621 
622 	if (msg->size > SN_AUX_MAX_PAYLOAD_BYTES)
623 		return -EINVAL;
624 
625 	switch (request) {
626 	case DP_AUX_NATIVE_WRITE:
627 	case DP_AUX_I2C_WRITE:
628 	case DP_AUX_NATIVE_READ:
629 	case DP_AUX_I2C_READ:
630 		regmap_write(pdata->regmap, SN_AUX_CMD_REG, request_val);
631 		break;
632 	default:
633 		return -EINVAL;
634 	}
635 
636 	regmap_write(pdata->regmap, SN_AUX_ADDR_19_16_REG,
637 		     (msg->address >> 16) & 0xF);
638 	regmap_write(pdata->regmap, SN_AUX_ADDR_15_8_REG,
639 		     (msg->address >> 8) & 0xFF);
640 	regmap_write(pdata->regmap, SN_AUX_ADDR_7_0_REG, msg->address & 0xFF);
641 
642 	regmap_write(pdata->regmap, SN_AUX_LENGTH_REG, msg->size);
643 
644 	if (request == DP_AUX_NATIVE_WRITE || request == DP_AUX_I2C_WRITE) {
645 		for (i = 0; i < msg->size; i++)
646 			regmap_write(pdata->regmap, SN_AUX_WDATA_REG(i),
647 				     buf[i]);
648 	}
649 
650 	regmap_write(pdata->regmap, SN_AUX_CMD_REG, request_val | AUX_CMD_SEND);
651 
652 	ret = regmap_read_poll_timeout(pdata->regmap, SN_AUX_CMD_REG, val,
653 				       !(val & AUX_CMD_SEND), 200,
654 				       50 * 1000);
655 	if (ret)
656 		return ret;
657 
658 	ret = regmap_read(pdata->regmap, SN_AUX_CMD_STATUS_REG, &val);
659 	if (ret)
660 		return ret;
661 	else if ((val & AUX_IRQ_STATUS_NAT_I2C_FAIL)
662 		 || (val & AUX_IRQ_STATUS_AUX_RPLY_TOUT)
663 		 || (val & AUX_IRQ_STATUS_AUX_SHORT))
664 		return -ENXIO;
665 
666 	if (request == DP_AUX_NATIVE_WRITE || request == DP_AUX_I2C_WRITE)
667 		return msg->size;
668 
669 	for (i = 0; i < msg->size; i++) {
670 		unsigned int val;
671 		ret = regmap_read(pdata->regmap, SN_AUX_RDATA_REG(i),
672 				  &val);
673 		if (ret)
674 			return ret;
675 
676 		WARN_ON(val & ~0xFF);
677 		buf[i] = (u8)(val & 0xFF);
678 	}
679 
680 	return msg->size;
681 }
682 
683 static int ti_sn_bridge_parse_dsi_host(struct ti_sn_bridge *pdata)
684 {
685 	struct device_node *np = pdata->dev->of_node;
686 
687 	pdata->host_node = of_graph_get_remote_node(np, 0, 0);
688 
689 	if (!pdata->host_node) {
690 		DRM_ERROR("remote dsi host node not found\n");
691 		return -ENODEV;
692 	}
693 
694 	return 0;
695 }
696 
697 static int ti_sn_bridge_probe(struct i2c_client *client,
698 			      const struct i2c_device_id *id)
699 {
700 	struct ti_sn_bridge *pdata;
701 	int ret;
702 
703 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
704 		DRM_ERROR("device doesn't support I2C\n");
705 		return -ENODEV;
706 	}
707 
708 	pdata = devm_kzalloc(&client->dev, sizeof(struct ti_sn_bridge),
709 			     GFP_KERNEL);
710 	if (!pdata)
711 		return -ENOMEM;
712 
713 	pdata->regmap = devm_regmap_init_i2c(client,
714 					     &ti_sn_bridge_regmap_config);
715 	if (IS_ERR(pdata->regmap)) {
716 		DRM_ERROR("regmap i2c init failed\n");
717 		return PTR_ERR(pdata->regmap);
718 	}
719 
720 	pdata->dev = &client->dev;
721 
722 	ret = drm_of_find_panel_or_bridge(pdata->dev->of_node, 1, 0,
723 					  &pdata->panel, NULL);
724 	if (ret) {
725 		DRM_ERROR("could not find any panel node\n");
726 		return ret;
727 	}
728 
729 	dev_set_drvdata(&client->dev, pdata);
730 
731 	pdata->enable_gpio = devm_gpiod_get(pdata->dev, "enable",
732 					    GPIOD_OUT_LOW);
733 	if (IS_ERR(pdata->enable_gpio)) {
734 		DRM_ERROR("failed to get enable gpio from DT\n");
735 		ret = PTR_ERR(pdata->enable_gpio);
736 		return ret;
737 	}
738 
739 	ret = ti_sn_bridge_parse_regulators(pdata);
740 	if (ret) {
741 		DRM_ERROR("failed to parse regulators\n");
742 		return ret;
743 	}
744 
745 	pdata->refclk = devm_clk_get(pdata->dev, "refclk");
746 	if (IS_ERR(pdata->refclk)) {
747 		ret = PTR_ERR(pdata->refclk);
748 		if (ret == -EPROBE_DEFER)
749 			return ret;
750 		DRM_DEBUG_KMS("refclk not found\n");
751 		pdata->refclk = NULL;
752 	}
753 
754 	ret = ti_sn_bridge_parse_dsi_host(pdata);
755 	if (ret)
756 		return ret;
757 
758 	pm_runtime_enable(pdata->dev);
759 
760 	i2c_set_clientdata(client, pdata);
761 
762 	pdata->aux.name = "ti-sn65dsi86-aux";
763 	pdata->aux.dev = pdata->dev;
764 	pdata->aux.transfer = ti_sn_aux_transfer;
765 	drm_dp_aux_register(&pdata->aux);
766 
767 	pdata->bridge.funcs = &ti_sn_bridge_funcs;
768 	pdata->bridge.of_node = client->dev.of_node;
769 
770 	drm_bridge_add(&pdata->bridge);
771 
772 	ti_sn_debugfs_init(pdata);
773 
774 	return 0;
775 }
776 
777 static int ti_sn_bridge_remove(struct i2c_client *client)
778 {
779 	struct ti_sn_bridge *pdata = i2c_get_clientdata(client);
780 
781 	if (!pdata)
782 		return -EINVAL;
783 
784 	ti_sn_debugfs_remove(pdata);
785 
786 	of_node_put(pdata->host_node);
787 
788 	pm_runtime_disable(pdata->dev);
789 
790 	if (pdata->dsi) {
791 		mipi_dsi_detach(pdata->dsi);
792 		mipi_dsi_device_unregister(pdata->dsi);
793 	}
794 
795 	drm_bridge_remove(&pdata->bridge);
796 
797 	return 0;
798 }
799 
800 static struct i2c_device_id ti_sn_bridge_id[] = {
801 	{ "ti,sn65dsi86", 0},
802 	{},
803 };
804 MODULE_DEVICE_TABLE(i2c, ti_sn_bridge_id);
805 
806 static const struct of_device_id ti_sn_bridge_match_table[] = {
807 	{.compatible = "ti,sn65dsi86"},
808 	{},
809 };
810 MODULE_DEVICE_TABLE(of, ti_sn_bridge_match_table);
811 
812 static struct i2c_driver ti_sn_bridge_driver = {
813 	.driver = {
814 		.name = "ti_sn65dsi86",
815 		.of_match_table = ti_sn_bridge_match_table,
816 		.pm = &ti_sn_bridge_pm_ops,
817 	},
818 	.probe = ti_sn_bridge_probe,
819 	.remove = ti_sn_bridge_remove,
820 	.id_table = ti_sn_bridge_id,
821 };
822 module_i2c_driver(ti_sn_bridge_driver);
823 
824 MODULE_AUTHOR("Sandeep Panda <spanda@codeaurora.org>");
825 MODULE_DESCRIPTION("sn65dsi86 DSI to eDP bridge driver");
826 MODULE_LICENSE("GPL v2");
827