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