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_bridge.h>
21 #include <drm/drm_dp_helper.h>
22 #include <drm/drm_mipi_dsi.h>
23 #include <drm/drm_of.h>
24 #include <drm/drm_panel.h>
25 #include <drm/drm_print.h>
26 #include <drm/drm_probe_helper.h>
27 
28 #define SN_DEVICE_REV_REG			0x08
29 #define SN_DPPLL_SRC_REG			0x0A
30 #define  DPPLL_CLK_SRC_DSICLK			BIT(0)
31 #define  REFCLK_FREQ_MASK			GENMASK(3, 1)
32 #define  REFCLK_FREQ(x)				((x) << 1)
33 #define  DPPLL_SRC_DP_PLL_LOCK			BIT(7)
34 #define SN_PLL_ENABLE_REG			0x0D
35 #define SN_DSI_LANES_REG			0x10
36 #define  CHA_DSI_LANES_MASK			GENMASK(4, 3)
37 #define  CHA_DSI_LANES(x)			((x) << 3)
38 #define SN_DSIA_CLK_FREQ_REG			0x12
39 #define SN_CHA_ACTIVE_LINE_LENGTH_LOW_REG	0x20
40 #define SN_CHA_VERTICAL_DISPLAY_SIZE_LOW_REG	0x24
41 #define SN_CHA_HSYNC_PULSE_WIDTH_LOW_REG	0x2C
42 #define SN_CHA_HSYNC_PULSE_WIDTH_HIGH_REG	0x2D
43 #define  CHA_HSYNC_POLARITY			BIT(7)
44 #define SN_CHA_VSYNC_PULSE_WIDTH_LOW_REG	0x30
45 #define SN_CHA_VSYNC_PULSE_WIDTH_HIGH_REG	0x31
46 #define  CHA_VSYNC_POLARITY			BIT(7)
47 #define SN_CHA_HORIZONTAL_BACK_PORCH_REG	0x34
48 #define SN_CHA_VERTICAL_BACK_PORCH_REG		0x36
49 #define SN_CHA_HORIZONTAL_FRONT_PORCH_REG	0x38
50 #define SN_CHA_VERTICAL_FRONT_PORCH_REG		0x3A
51 #define SN_ENH_FRAME_REG			0x5A
52 #define  VSTREAM_ENABLE				BIT(3)
53 #define SN_DATA_FORMAT_REG			0x5B
54 #define SN_HPD_DISABLE_REG			0x5C
55 #define  HPD_DISABLE				BIT(0)
56 #define SN_AUX_WDATA_REG(x)			(0x64 + (x))
57 #define SN_AUX_ADDR_19_16_REG			0x74
58 #define SN_AUX_ADDR_15_8_REG			0x75
59 #define SN_AUX_ADDR_7_0_REG			0x76
60 #define SN_AUX_LENGTH_REG			0x77
61 #define SN_AUX_CMD_REG				0x78
62 #define  AUX_CMD_SEND				BIT(0)
63 #define  AUX_CMD_REQ(x)				((x) << 4)
64 #define SN_AUX_RDATA_REG(x)			(0x79 + (x))
65 #define SN_SSC_CONFIG_REG			0x93
66 #define  DP_NUM_LANES_MASK			GENMASK(5, 4)
67 #define  DP_NUM_LANES(x)			((x) << 4)
68 #define SN_DATARATE_CONFIG_REG			0x94
69 #define  DP_DATARATE_MASK			GENMASK(7, 5)
70 #define  DP_DATARATE(x)				((x) << 5)
71 #define SN_ML_TX_MODE_REG			0x96
72 #define  ML_TX_MAIN_LINK_OFF			0
73 #define  ML_TX_NORMAL_MODE			BIT(0)
74 #define SN_AUX_CMD_STATUS_REG			0xF4
75 #define  AUX_IRQ_STATUS_AUX_RPLY_TOUT		BIT(3)
76 #define  AUX_IRQ_STATUS_AUX_SHORT		BIT(5)
77 #define  AUX_IRQ_STATUS_NAT_I2C_FAIL		BIT(6)
78 
79 #define MIN_DSI_CLK_FREQ_MHZ	40
80 
81 /* fudge factor required to account for 8b/10b encoding */
82 #define DP_CLK_FUDGE_NUM	10
83 #define DP_CLK_FUDGE_DEN	8
84 
85 /* Matches DP_AUX_MAX_PAYLOAD_BYTES (for now) */
86 #define SN_AUX_MAX_PAYLOAD_BYTES	16
87 
88 #define SN_REGULATOR_SUPPLY_NUM		4
89 
90 struct ti_sn_bridge {
91 	struct device			*dev;
92 	struct regmap			*regmap;
93 	struct drm_dp_aux		aux;
94 	struct drm_bridge		bridge;
95 	struct drm_connector		connector;
96 	struct dentry			*debugfs;
97 	struct device_node		*host_node;
98 	struct mipi_dsi_device		*dsi;
99 	struct clk			*refclk;
100 	struct drm_panel		*panel;
101 	struct gpio_desc		*enable_gpio;
102 	struct regulator_bulk_data	supplies[SN_REGULATOR_SUPPLY_NUM];
103 };
104 
105 static const struct regmap_range ti_sn_bridge_volatile_ranges[] = {
106 	{ .range_min = 0, .range_max = 0xFF },
107 };
108 
109 static const struct regmap_access_table ti_sn_bridge_volatile_table = {
110 	.yes_ranges = ti_sn_bridge_volatile_ranges,
111 	.n_yes_ranges = ARRAY_SIZE(ti_sn_bridge_volatile_ranges),
112 };
113 
114 static const struct regmap_config ti_sn_bridge_regmap_config = {
115 	.reg_bits = 8,
116 	.val_bits = 8,
117 	.volatile_table = &ti_sn_bridge_volatile_table,
118 	.cache_type = REGCACHE_NONE,
119 };
120 
121 static void ti_sn_bridge_write_u16(struct ti_sn_bridge *pdata,
122 				   unsigned int reg, u16 val)
123 {
124 	regmap_write(pdata->regmap, reg, val & 0xFF);
125 	regmap_write(pdata->regmap, reg + 1, val >> 8);
126 }
127 
128 static int __maybe_unused ti_sn_bridge_resume(struct device *dev)
129 {
130 	struct ti_sn_bridge *pdata = dev_get_drvdata(dev);
131 	int ret;
132 
133 	ret = regulator_bulk_enable(SN_REGULATOR_SUPPLY_NUM, pdata->supplies);
134 	if (ret) {
135 		DRM_ERROR("failed to enable supplies %d\n", ret);
136 		return ret;
137 	}
138 
139 	gpiod_set_value(pdata->enable_gpio, 1);
140 
141 	return ret;
142 }
143 
144 static int __maybe_unused ti_sn_bridge_suspend(struct device *dev)
145 {
146 	struct ti_sn_bridge *pdata = dev_get_drvdata(dev);
147 	int ret;
148 
149 	gpiod_set_value(pdata->enable_gpio, 0);
150 
151 	ret = regulator_bulk_disable(SN_REGULATOR_SUPPLY_NUM, pdata->supplies);
152 	if (ret)
153 		DRM_ERROR("failed to disable supplies %d\n", ret);
154 
155 	return ret;
156 }
157 
158 static const struct dev_pm_ops ti_sn_bridge_pm_ops = {
159 	SET_RUNTIME_PM_OPS(ti_sn_bridge_suspend, ti_sn_bridge_resume, NULL)
160 };
161 
162 static int status_show(struct seq_file *s, void *data)
163 {
164 	struct ti_sn_bridge *pdata = s->private;
165 	unsigned int reg, val;
166 
167 	seq_puts(s, "STATUS REGISTERS:\n");
168 
169 	pm_runtime_get_sync(pdata->dev);
170 
171 	/* IRQ Status Registers, see Table 31 in datasheet */
172 	for (reg = 0xf0; reg <= 0xf8; reg++) {
173 		regmap_read(pdata->regmap, reg, &val);
174 		seq_printf(s, "[0x%02x] = 0x%08x\n", reg, val);
175 	}
176 
177 	pm_runtime_put(pdata->dev);
178 
179 	return 0;
180 }
181 
182 DEFINE_SHOW_ATTRIBUTE(status);
183 
184 static void ti_sn_debugfs_init(struct ti_sn_bridge *pdata)
185 {
186 	pdata->debugfs = debugfs_create_dir(dev_name(pdata->dev), NULL);
187 
188 	debugfs_create_file("status", 0600, pdata->debugfs, pdata,
189 			&status_fops);
190 }
191 
192 static void ti_sn_debugfs_remove(struct ti_sn_bridge *pdata)
193 {
194 	debugfs_remove_recursive(pdata->debugfs);
195 	pdata->debugfs = NULL;
196 }
197 
198 /* Connector funcs */
199 static struct ti_sn_bridge *
200 connector_to_ti_sn_bridge(struct drm_connector *connector)
201 {
202 	return container_of(connector, struct ti_sn_bridge, connector);
203 }
204 
205 static int ti_sn_bridge_connector_get_modes(struct drm_connector *connector)
206 {
207 	struct ti_sn_bridge *pdata = connector_to_ti_sn_bridge(connector);
208 
209 	return drm_panel_get_modes(pdata->panel, connector);
210 }
211 
212 static enum drm_mode_status
213 ti_sn_bridge_connector_mode_valid(struct drm_connector *connector,
214 				  struct drm_display_mode *mode)
215 {
216 	/* maximum supported resolution is 4K at 60 fps */
217 	if (mode->clock > 594000)
218 		return MODE_CLOCK_HIGH;
219 
220 	return MODE_OK;
221 }
222 
223 static struct drm_connector_helper_funcs ti_sn_bridge_connector_helper_funcs = {
224 	.get_modes = ti_sn_bridge_connector_get_modes,
225 	.mode_valid = ti_sn_bridge_connector_mode_valid,
226 };
227 
228 static enum drm_connector_status
229 ti_sn_bridge_connector_detect(struct drm_connector *connector, bool force)
230 {
231 	/**
232 	 * TODO: Currently if drm_panel is present, then always
233 	 * return the status as connected. Need to add support to detect
234 	 * device state for hot pluggable scenarios.
235 	 */
236 	return connector_status_connected;
237 }
238 
239 static const struct drm_connector_funcs ti_sn_bridge_connector_funcs = {
240 	.fill_modes = drm_helper_probe_single_connector_modes,
241 	.detect = ti_sn_bridge_connector_detect,
242 	.destroy = drm_connector_cleanup,
243 	.reset = drm_atomic_helper_connector_reset,
244 	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
245 	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
246 };
247 
248 static struct ti_sn_bridge *bridge_to_ti_sn_bridge(struct drm_bridge *bridge)
249 {
250 	return container_of(bridge, struct ti_sn_bridge, bridge);
251 }
252 
253 static int ti_sn_bridge_parse_regulators(struct ti_sn_bridge *pdata)
254 {
255 	unsigned int i;
256 	const char * const ti_sn_bridge_supply_names[] = {
257 		"vcca", "vcc", "vccio", "vpll",
258 	};
259 
260 	for (i = 0; i < SN_REGULATOR_SUPPLY_NUM; i++)
261 		pdata->supplies[i].supply = ti_sn_bridge_supply_names[i];
262 
263 	return devm_regulator_bulk_get(pdata->dev, SN_REGULATOR_SUPPLY_NUM,
264 				       pdata->supplies);
265 }
266 
267 static int ti_sn_bridge_attach(struct drm_bridge *bridge)
268 {
269 	int ret, val;
270 	struct ti_sn_bridge *pdata = bridge_to_ti_sn_bridge(bridge);
271 	struct mipi_dsi_host *host;
272 	struct mipi_dsi_device *dsi;
273 	const struct mipi_dsi_device_info info = { .type = "ti_sn_bridge",
274 						   .channel = 0,
275 						   .node = NULL,
276 						 };
277 
278 	ret = drm_connector_init(bridge->dev, &pdata->connector,
279 				 &ti_sn_bridge_connector_funcs,
280 				 DRM_MODE_CONNECTOR_eDP);
281 	if (ret) {
282 		DRM_ERROR("Failed to initialize connector with drm\n");
283 		return ret;
284 	}
285 
286 	drm_connector_helper_add(&pdata->connector,
287 				 &ti_sn_bridge_connector_helper_funcs);
288 	drm_connector_attach_encoder(&pdata->connector, bridge->encoder);
289 
290 	/*
291 	 * TODO: ideally finding host resource and dsi dev registration needs
292 	 * to be done in bridge probe. But some existing DSI host drivers will
293 	 * wait for any of the drm_bridge/drm_panel to get added to the global
294 	 * bridge/panel list, before completing their probe. So if we do the
295 	 * dsi dev registration part in bridge probe, before populating in
296 	 * the global bridge list, then it will cause deadlock as dsi host probe
297 	 * will never complete, neither our bridge probe. So keeping it here
298 	 * will satisfy most of the existing host drivers. Once the host driver
299 	 * is fixed we can move the below code to bridge probe safely.
300 	 */
301 	host = of_find_mipi_dsi_host_by_node(pdata->host_node);
302 	if (!host) {
303 		DRM_ERROR("failed to find dsi host\n");
304 		ret = -ENODEV;
305 		goto err_dsi_host;
306 	}
307 
308 	dsi = mipi_dsi_device_register_full(host, &info);
309 	if (IS_ERR(dsi)) {
310 		DRM_ERROR("failed to create dsi device\n");
311 		ret = PTR_ERR(dsi);
312 		goto err_dsi_host;
313 	}
314 
315 	/* TODO: setting to 4 lanes always for now */
316 	dsi->lanes = 4;
317 	dsi->format = MIPI_DSI_FMT_RGB888;
318 	dsi->mode_flags = MIPI_DSI_MODE_VIDEO;
319 
320 	/* check if continuous dsi clock is required or not */
321 	pm_runtime_get_sync(pdata->dev);
322 	regmap_read(pdata->regmap, SN_DPPLL_SRC_REG, &val);
323 	pm_runtime_put(pdata->dev);
324 	if (!(val & DPPLL_CLK_SRC_DSICLK))
325 		dsi->mode_flags |= MIPI_DSI_CLOCK_NON_CONTINUOUS;
326 
327 	ret = mipi_dsi_attach(dsi);
328 	if (ret < 0) {
329 		DRM_ERROR("failed to attach dsi to host\n");
330 		goto err_dsi_attach;
331 	}
332 	pdata->dsi = dsi;
333 
334 	/* attach panel to bridge */
335 	drm_panel_attach(pdata->panel, &pdata->connector);
336 
337 	return 0;
338 
339 err_dsi_attach:
340 	mipi_dsi_device_unregister(dsi);
341 err_dsi_host:
342 	drm_connector_cleanup(&pdata->connector);
343 	return ret;
344 }
345 
346 static void ti_sn_bridge_disable(struct drm_bridge *bridge)
347 {
348 	struct ti_sn_bridge *pdata = bridge_to_ti_sn_bridge(bridge);
349 
350 	drm_panel_disable(pdata->panel);
351 
352 	/* disable video stream */
353 	regmap_update_bits(pdata->regmap, SN_ENH_FRAME_REG, VSTREAM_ENABLE, 0);
354 	/* semi auto link training mode OFF */
355 	regmap_write(pdata->regmap, SN_ML_TX_MODE_REG, 0);
356 	/* disable DP PLL */
357 	regmap_write(pdata->regmap, SN_PLL_ENABLE_REG, 0);
358 
359 	drm_panel_unprepare(pdata->panel);
360 }
361 
362 static u32 ti_sn_bridge_get_dsi_freq(struct ti_sn_bridge *pdata)
363 {
364 	u32 bit_rate_khz, clk_freq_khz;
365 	struct drm_display_mode *mode =
366 		&pdata->bridge.encoder->crtc->state->adjusted_mode;
367 
368 	bit_rate_khz = mode->clock *
369 			mipi_dsi_pixel_format_to_bpp(pdata->dsi->format);
370 	clk_freq_khz = bit_rate_khz / (pdata->dsi->lanes * 2);
371 
372 	return clk_freq_khz;
373 }
374 
375 /* clk frequencies supported by bridge in Hz in case derived from REFCLK pin */
376 static const u32 ti_sn_bridge_refclk_lut[] = {
377 	12000000,
378 	19200000,
379 	26000000,
380 	27000000,
381 	38400000,
382 };
383 
384 /* clk frequencies supported by bridge in Hz in case derived from DACP/N pin */
385 static const u32 ti_sn_bridge_dsiclk_lut[] = {
386 	468000000,
387 	384000000,
388 	416000000,
389 	486000000,
390 	460800000,
391 };
392 
393 static void ti_sn_bridge_set_refclk_freq(struct ti_sn_bridge *pdata)
394 {
395 	int i;
396 	u32 refclk_rate;
397 	const u32 *refclk_lut;
398 	size_t refclk_lut_size;
399 
400 	if (pdata->refclk) {
401 		refclk_rate = clk_get_rate(pdata->refclk);
402 		refclk_lut = ti_sn_bridge_refclk_lut;
403 		refclk_lut_size = ARRAY_SIZE(ti_sn_bridge_refclk_lut);
404 		clk_prepare_enable(pdata->refclk);
405 	} else {
406 		refclk_rate = ti_sn_bridge_get_dsi_freq(pdata) * 1000;
407 		refclk_lut = ti_sn_bridge_dsiclk_lut;
408 		refclk_lut_size = ARRAY_SIZE(ti_sn_bridge_dsiclk_lut);
409 	}
410 
411 	/* for i equals to refclk_lut_size means default frequency */
412 	for (i = 0; i < refclk_lut_size; i++)
413 		if (refclk_lut[i] == refclk_rate)
414 			break;
415 
416 	regmap_update_bits(pdata->regmap, SN_DPPLL_SRC_REG, REFCLK_FREQ_MASK,
417 			   REFCLK_FREQ(i));
418 }
419 
420 /**
421  * LUT index corresponds to register value and
422  * LUT values corresponds to dp data rate supported
423  * by the bridge in Mbps unit.
424  */
425 static const unsigned int ti_sn_bridge_dp_rate_lut[] = {
426 	0, 1620, 2160, 2430, 2700, 3240, 4320, 5400
427 };
428 
429 static void ti_sn_bridge_set_dsi_dp_rate(struct ti_sn_bridge *pdata)
430 {
431 	unsigned int bit_rate_mhz, clk_freq_mhz, dp_rate_mhz;
432 	unsigned int val, i;
433 	struct drm_display_mode *mode =
434 		&pdata->bridge.encoder->crtc->state->adjusted_mode;
435 
436 	/* set DSIA clk frequency */
437 	bit_rate_mhz = (mode->clock / 1000) *
438 			mipi_dsi_pixel_format_to_bpp(pdata->dsi->format);
439 	clk_freq_mhz = bit_rate_mhz / (pdata->dsi->lanes * 2);
440 
441 	/* for each increment in val, frequency increases by 5MHz */
442 	val = (MIN_DSI_CLK_FREQ_MHZ / 5) +
443 		(((clk_freq_mhz - MIN_DSI_CLK_FREQ_MHZ) / 5) & 0xFF);
444 	regmap_write(pdata->regmap, SN_DSIA_CLK_FREQ_REG, val);
445 
446 	/* set DP data rate */
447 	dp_rate_mhz = ((bit_rate_mhz / pdata->dsi->lanes) * DP_CLK_FUDGE_NUM) /
448 							DP_CLK_FUDGE_DEN;
449 	for (i = 0; i < ARRAY_SIZE(ti_sn_bridge_dp_rate_lut) - 1; i++)
450 		if (ti_sn_bridge_dp_rate_lut[i] > dp_rate_mhz)
451 			break;
452 
453 	regmap_update_bits(pdata->regmap, SN_DATARATE_CONFIG_REG,
454 			   DP_DATARATE_MASK, DP_DATARATE(i));
455 }
456 
457 static void ti_sn_bridge_set_video_timings(struct ti_sn_bridge *pdata)
458 {
459 	struct drm_display_mode *mode =
460 		&pdata->bridge.encoder->crtc->state->adjusted_mode;
461 	u8 hsync_polarity = 0, vsync_polarity = 0;
462 
463 	if (mode->flags & DRM_MODE_FLAG_PHSYNC)
464 		hsync_polarity = CHA_HSYNC_POLARITY;
465 	if (mode->flags & DRM_MODE_FLAG_PVSYNC)
466 		vsync_polarity = CHA_VSYNC_POLARITY;
467 
468 	ti_sn_bridge_write_u16(pdata, SN_CHA_ACTIVE_LINE_LENGTH_LOW_REG,
469 			       mode->hdisplay);
470 	ti_sn_bridge_write_u16(pdata, SN_CHA_VERTICAL_DISPLAY_SIZE_LOW_REG,
471 			       mode->vdisplay);
472 	regmap_write(pdata->regmap, SN_CHA_HSYNC_PULSE_WIDTH_LOW_REG,
473 		     (mode->hsync_end - mode->hsync_start) & 0xFF);
474 	regmap_write(pdata->regmap, SN_CHA_HSYNC_PULSE_WIDTH_HIGH_REG,
475 		     (((mode->hsync_end - mode->hsync_start) >> 8) & 0x7F) |
476 		     hsync_polarity);
477 	regmap_write(pdata->regmap, SN_CHA_VSYNC_PULSE_WIDTH_LOW_REG,
478 		     (mode->vsync_end - mode->vsync_start) & 0xFF);
479 	regmap_write(pdata->regmap, SN_CHA_VSYNC_PULSE_WIDTH_HIGH_REG,
480 		     (((mode->vsync_end - mode->vsync_start) >> 8) & 0x7F) |
481 		     vsync_polarity);
482 
483 	regmap_write(pdata->regmap, SN_CHA_HORIZONTAL_BACK_PORCH_REG,
484 		     (mode->htotal - mode->hsync_end) & 0xFF);
485 	regmap_write(pdata->regmap, SN_CHA_VERTICAL_BACK_PORCH_REG,
486 		     (mode->vtotal - mode->vsync_end) & 0xFF);
487 
488 	regmap_write(pdata->regmap, SN_CHA_HORIZONTAL_FRONT_PORCH_REG,
489 		     (mode->hsync_start - mode->hdisplay) & 0xFF);
490 	regmap_write(pdata->regmap, SN_CHA_VERTICAL_FRONT_PORCH_REG,
491 		     (mode->vsync_start - mode->vdisplay) & 0xFF);
492 
493 	usleep_range(10000, 10500); /* 10ms delay recommended by spec */
494 }
495 
496 static void ti_sn_bridge_enable(struct drm_bridge *bridge)
497 {
498 	struct ti_sn_bridge *pdata = bridge_to_ti_sn_bridge(bridge);
499 	unsigned int val;
500 	int ret;
501 
502 	/* DSI_A lane config */
503 	val = CHA_DSI_LANES(4 - pdata->dsi->lanes);
504 	regmap_update_bits(pdata->regmap, SN_DSI_LANES_REG,
505 			   CHA_DSI_LANES_MASK, val);
506 
507 	/* DP lane config */
508 	val = DP_NUM_LANES(pdata->dsi->lanes - 1);
509 	regmap_update_bits(pdata->regmap, SN_SSC_CONFIG_REG, DP_NUM_LANES_MASK,
510 			   val);
511 
512 	/* set dsi/dp clk frequency value */
513 	ti_sn_bridge_set_dsi_dp_rate(pdata);
514 
515 	/* enable DP PLL */
516 	regmap_write(pdata->regmap, SN_PLL_ENABLE_REG, 1);
517 
518 	ret = regmap_read_poll_timeout(pdata->regmap, SN_DPPLL_SRC_REG, val,
519 				       val & DPPLL_SRC_DP_PLL_LOCK, 1000,
520 				       50 * 1000);
521 	if (ret) {
522 		DRM_ERROR("DP_PLL_LOCK polling failed (%d)\n", ret);
523 		return;
524 	}
525 
526 	/**
527 	 * The SN65DSI86 only supports ASSR Display Authentication method and
528 	 * this method is enabled by default. An eDP panel must support this
529 	 * authentication method. We need to enable this method in the eDP panel
530 	 * at DisplayPort address 0x0010A prior to link training.
531 	 */
532 	drm_dp_dpcd_writeb(&pdata->aux, DP_EDP_CONFIGURATION_SET,
533 			   DP_ALTERNATE_SCRAMBLER_RESET_ENABLE);
534 
535 	/* Semi auto link training mode */
536 	regmap_write(pdata->regmap, SN_ML_TX_MODE_REG, 0x0A);
537 	ret = regmap_read_poll_timeout(pdata->regmap, SN_ML_TX_MODE_REG, val,
538 				       val == ML_TX_MAIN_LINK_OFF ||
539 				       val == ML_TX_NORMAL_MODE, 1000,
540 				       500 * 1000);
541 	if (ret) {
542 		DRM_ERROR("Training complete polling failed (%d)\n", ret);
543 		return;
544 	} else if (val == ML_TX_MAIN_LINK_OFF) {
545 		DRM_ERROR("Link training failed, link is off\n");
546 		return;
547 	}
548 
549 	/* config video parameters */
550 	ti_sn_bridge_set_video_timings(pdata);
551 
552 	/* enable video stream */
553 	regmap_update_bits(pdata->regmap, SN_ENH_FRAME_REG, VSTREAM_ENABLE,
554 			   VSTREAM_ENABLE);
555 
556 	drm_panel_enable(pdata->panel);
557 }
558 
559 static void ti_sn_bridge_pre_enable(struct drm_bridge *bridge)
560 {
561 	struct ti_sn_bridge *pdata = bridge_to_ti_sn_bridge(bridge);
562 
563 	pm_runtime_get_sync(pdata->dev);
564 
565 	/* configure bridge ref_clk */
566 	ti_sn_bridge_set_refclk_freq(pdata);
567 
568 	/*
569 	 * HPD on this bridge chip is a bit useless.  This is an eDP bridge
570 	 * so the HPD is an internal signal that's only there to signal that
571 	 * the panel is done powering up.  ...but the bridge chip debounces
572 	 * this signal by between 100 ms and 400 ms (depending on process,
573 	 * voltage, and temperate--I measured it at about 200 ms).  One
574 	 * particular panel asserted HPD 84 ms after it was powered on meaning
575 	 * that we saw HPD 284 ms after power on.  ...but the same panel said
576 	 * that instead of looking at HPD you could just hardcode a delay of
577 	 * 200 ms.  We'll assume that the panel driver will have the hardcoded
578 	 * delay in its prepare and always disable HPD.
579 	 *
580 	 * If HPD somehow makes sense on some future panel we'll have to
581 	 * change this to be conditional on someone specifying that HPD should
582 	 * be used.
583 	 */
584 	regmap_update_bits(pdata->regmap, SN_HPD_DISABLE_REG, HPD_DISABLE,
585 			   HPD_DISABLE);
586 
587 	drm_panel_prepare(pdata->panel);
588 }
589 
590 static void ti_sn_bridge_post_disable(struct drm_bridge *bridge)
591 {
592 	struct ti_sn_bridge *pdata = bridge_to_ti_sn_bridge(bridge);
593 
594 	if (pdata->refclk)
595 		clk_disable_unprepare(pdata->refclk);
596 
597 	pm_runtime_put_sync(pdata->dev);
598 }
599 
600 static const struct drm_bridge_funcs ti_sn_bridge_funcs = {
601 	.attach = ti_sn_bridge_attach,
602 	.pre_enable = ti_sn_bridge_pre_enable,
603 	.enable = ti_sn_bridge_enable,
604 	.disable = ti_sn_bridge_disable,
605 	.post_disable = ti_sn_bridge_post_disable,
606 };
607 
608 static struct ti_sn_bridge *aux_to_ti_sn_bridge(struct drm_dp_aux *aux)
609 {
610 	return container_of(aux, struct ti_sn_bridge, aux);
611 }
612 
613 static ssize_t ti_sn_aux_transfer(struct drm_dp_aux *aux,
614 				  struct drm_dp_aux_msg *msg)
615 {
616 	struct ti_sn_bridge *pdata = aux_to_ti_sn_bridge(aux);
617 	u32 request = msg->request & ~DP_AUX_I2C_MOT;
618 	u32 request_val = AUX_CMD_REQ(msg->request);
619 	u8 *buf = (u8 *)msg->buffer;
620 	unsigned int val;
621 	int ret, i;
622 
623 	if (msg->size > SN_AUX_MAX_PAYLOAD_BYTES)
624 		return -EINVAL;
625 
626 	switch (request) {
627 	case DP_AUX_NATIVE_WRITE:
628 	case DP_AUX_I2C_WRITE:
629 	case DP_AUX_NATIVE_READ:
630 	case DP_AUX_I2C_READ:
631 		regmap_write(pdata->regmap, SN_AUX_CMD_REG, request_val);
632 		break;
633 	default:
634 		return -EINVAL;
635 	}
636 
637 	regmap_write(pdata->regmap, SN_AUX_ADDR_19_16_REG,
638 		     (msg->address >> 16) & 0xF);
639 	regmap_write(pdata->regmap, SN_AUX_ADDR_15_8_REG,
640 		     (msg->address >> 8) & 0xFF);
641 	regmap_write(pdata->regmap, SN_AUX_ADDR_7_0_REG, msg->address & 0xFF);
642 
643 	regmap_write(pdata->regmap, SN_AUX_LENGTH_REG, msg->size);
644 
645 	if (request == DP_AUX_NATIVE_WRITE || request == DP_AUX_I2C_WRITE) {
646 		for (i = 0; i < msg->size; i++)
647 			regmap_write(pdata->regmap, SN_AUX_WDATA_REG(i),
648 				     buf[i]);
649 	}
650 
651 	regmap_write(pdata->regmap, SN_AUX_CMD_REG, request_val | AUX_CMD_SEND);
652 
653 	ret = regmap_read_poll_timeout(pdata->regmap, SN_AUX_CMD_REG, val,
654 				       !(val & AUX_CMD_SEND), 200,
655 				       50 * 1000);
656 	if (ret)
657 		return ret;
658 
659 	ret = regmap_read(pdata->regmap, SN_AUX_CMD_STATUS_REG, &val);
660 	if (ret)
661 		return ret;
662 	else if ((val & AUX_IRQ_STATUS_NAT_I2C_FAIL)
663 		 || (val & AUX_IRQ_STATUS_AUX_RPLY_TOUT)
664 		 || (val & AUX_IRQ_STATUS_AUX_SHORT))
665 		return -ENXIO;
666 
667 	if (request == DP_AUX_NATIVE_WRITE || request == DP_AUX_I2C_WRITE)
668 		return msg->size;
669 
670 	for (i = 0; i < msg->size; i++) {
671 		unsigned int val;
672 		ret = regmap_read(pdata->regmap, SN_AUX_RDATA_REG(i),
673 				  &val);
674 		if (ret)
675 			return ret;
676 
677 		WARN_ON(val & ~0xFF);
678 		buf[i] = (u8)(val & 0xFF);
679 	}
680 
681 	return msg->size;
682 }
683 
684 static int ti_sn_bridge_parse_dsi_host(struct ti_sn_bridge *pdata)
685 {
686 	struct device_node *np = pdata->dev->of_node;
687 
688 	pdata->host_node = of_graph_get_remote_node(np, 0, 0);
689 
690 	if (!pdata->host_node) {
691 		DRM_ERROR("remote dsi host node not found\n");
692 		return -ENODEV;
693 	}
694 
695 	return 0;
696 }
697 
698 static int ti_sn_bridge_probe(struct i2c_client *client,
699 			      const struct i2c_device_id *id)
700 {
701 	struct ti_sn_bridge *pdata;
702 	int ret;
703 
704 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
705 		DRM_ERROR("device doesn't support I2C\n");
706 		return -ENODEV;
707 	}
708 
709 	pdata = devm_kzalloc(&client->dev, sizeof(struct ti_sn_bridge),
710 			     GFP_KERNEL);
711 	if (!pdata)
712 		return -ENOMEM;
713 
714 	pdata->regmap = devm_regmap_init_i2c(client,
715 					     &ti_sn_bridge_regmap_config);
716 	if (IS_ERR(pdata->regmap)) {
717 		DRM_ERROR("regmap i2c init failed\n");
718 		return PTR_ERR(pdata->regmap);
719 	}
720 
721 	pdata->dev = &client->dev;
722 
723 	ret = drm_of_find_panel_or_bridge(pdata->dev->of_node, 1, 0,
724 					  &pdata->panel, NULL);
725 	if (ret) {
726 		DRM_ERROR("could not find any panel node\n");
727 		return ret;
728 	}
729 
730 	dev_set_drvdata(&client->dev, pdata);
731 
732 	pdata->enable_gpio = devm_gpiod_get(pdata->dev, "enable",
733 					    GPIOD_OUT_LOW);
734 	if (IS_ERR(pdata->enable_gpio)) {
735 		DRM_ERROR("failed to get enable gpio from DT\n");
736 		ret = PTR_ERR(pdata->enable_gpio);
737 		return ret;
738 	}
739 
740 	ret = ti_sn_bridge_parse_regulators(pdata);
741 	if (ret) {
742 		DRM_ERROR("failed to parse regulators\n");
743 		return ret;
744 	}
745 
746 	pdata->refclk = devm_clk_get(pdata->dev, "refclk");
747 	if (IS_ERR(pdata->refclk)) {
748 		ret = PTR_ERR(pdata->refclk);
749 		if (ret == -EPROBE_DEFER)
750 			return ret;
751 		DRM_DEBUG_KMS("refclk not found\n");
752 		pdata->refclk = NULL;
753 	}
754 
755 	ret = ti_sn_bridge_parse_dsi_host(pdata);
756 	if (ret)
757 		return ret;
758 
759 	pm_runtime_enable(pdata->dev);
760 
761 	i2c_set_clientdata(client, pdata);
762 
763 	pdata->aux.name = "ti-sn65dsi86-aux";
764 	pdata->aux.dev = pdata->dev;
765 	pdata->aux.transfer = ti_sn_aux_transfer;
766 	drm_dp_aux_register(&pdata->aux);
767 
768 	pdata->bridge.funcs = &ti_sn_bridge_funcs;
769 	pdata->bridge.of_node = client->dev.of_node;
770 
771 	drm_bridge_add(&pdata->bridge);
772 
773 	ti_sn_debugfs_init(pdata);
774 
775 	return 0;
776 }
777 
778 static int ti_sn_bridge_remove(struct i2c_client *client)
779 {
780 	struct ti_sn_bridge *pdata = i2c_get_clientdata(client);
781 
782 	if (!pdata)
783 		return -EINVAL;
784 
785 	ti_sn_debugfs_remove(pdata);
786 
787 	of_node_put(pdata->host_node);
788 
789 	pm_runtime_disable(pdata->dev);
790 
791 	if (pdata->dsi) {
792 		mipi_dsi_detach(pdata->dsi);
793 		mipi_dsi_device_unregister(pdata->dsi);
794 	}
795 
796 	drm_bridge_remove(&pdata->bridge);
797 
798 	return 0;
799 }
800 
801 static struct i2c_device_id ti_sn_bridge_id[] = {
802 	{ "ti,sn65dsi86", 0},
803 	{},
804 };
805 MODULE_DEVICE_TABLE(i2c, ti_sn_bridge_id);
806 
807 static const struct of_device_id ti_sn_bridge_match_table[] = {
808 	{.compatible = "ti,sn65dsi86"},
809 	{},
810 };
811 MODULE_DEVICE_TABLE(of, ti_sn_bridge_match_table);
812 
813 static struct i2c_driver ti_sn_bridge_driver = {
814 	.driver = {
815 		.name = "ti_sn65dsi86",
816 		.of_match_table = ti_sn_bridge_match_table,
817 		.pm = &ti_sn_bridge_pm_ops,
818 	},
819 	.probe = ti_sn_bridge_probe,
820 	.remove = ti_sn_bridge_remove,
821 	.id_table = ti_sn_bridge_id,
822 };
823 module_i2c_driver(ti_sn_bridge_driver);
824 
825 MODULE_AUTHOR("Sandeep Panda <spanda@codeaurora.org>");
826 MODULE_DESCRIPTION("sn65dsi86 DSI to eDP bridge driver");
827 MODULE_LICENSE("GPL v2");
828