Training courses

Kernel and Embedded Linux

Bootlin training courses

Embedded Linux, kernel,
Yocto Project, Buildroot, real-time,
graphics, boot time, debugging...

Bootlin logo

Elixir Cross Referencer

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
/*
 * Copyright © 2014 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 *
 * Author: Shobhit Kumar <shobhit.kumar@intel.com>
 *
 */

#include <drm/drmP.h>
#include <drm/drm_crtc.h>
#include <drm/drm_edid.h>
#include <drm/i915_drm.h>
#include <drm/drm_panel.h>
#include <linux/slab.h>
#include <video/mipi_display.h>
#include <asm/intel-mid.h>
#include <video/mipi_display.h>
#include "i915_drv.h"
#include "intel_drv.h"
#include "intel_dsi.h"

struct vbt_panel {
	struct drm_panel panel;
	struct intel_dsi *intel_dsi;
};

static inline struct vbt_panel *to_vbt_panel(struct drm_panel *panel)
{
	return container_of(panel, struct vbt_panel, panel);
}

#define MIPI_TRANSFER_MODE_SHIFT	0
#define MIPI_VIRTUAL_CHANNEL_SHIFT	1
#define MIPI_PORT_SHIFT			3

#define PREPARE_CNT_MAX		0x3F
#define EXIT_ZERO_CNT_MAX	0x3F
#define CLK_ZERO_CNT_MAX	0xFF
#define TRAIL_CNT_MAX		0x1F

#define NS_KHZ_RATIO 1000000

/* base offsets for gpio pads */
#define VLV_GPIO_NC_0_HV_DDI0_HPD	0x4130
#define VLV_GPIO_NC_1_HV_DDI0_DDC_SDA	0x4120
#define VLV_GPIO_NC_2_HV_DDI0_DDC_SCL	0x4110
#define VLV_GPIO_NC_3_PANEL0_VDDEN	0x4140
#define VLV_GPIO_NC_4_PANEL0_BKLTEN	0x4150
#define VLV_GPIO_NC_5_PANEL0_BKLTCTL	0x4160
#define VLV_GPIO_NC_6_HV_DDI1_HPD	0x4180
#define VLV_GPIO_NC_7_HV_DDI1_DDC_SDA	0x4190
#define VLV_GPIO_NC_8_HV_DDI1_DDC_SCL	0x4170
#define VLV_GPIO_NC_9_PANEL1_VDDEN	0x4100
#define VLV_GPIO_NC_10_PANEL1_BKLTEN	0x40E0
#define VLV_GPIO_NC_11_PANEL1_BKLTCTL	0x40F0

#define VLV_GPIO_PCONF0(base_offset)	(base_offset)
#define VLV_GPIO_PAD_VAL(base_offset)	((base_offset) + 8)

struct gpio_map {
	u16 base_offset;
	bool init;
};

static struct gpio_map vlv_gpio_table[] = {
	{ VLV_GPIO_NC_0_HV_DDI0_HPD },
	{ VLV_GPIO_NC_1_HV_DDI0_DDC_SDA },
	{ VLV_GPIO_NC_2_HV_DDI0_DDC_SCL },
	{ VLV_GPIO_NC_3_PANEL0_VDDEN },
	{ VLV_GPIO_NC_4_PANEL0_BKLTEN },
	{ VLV_GPIO_NC_5_PANEL0_BKLTCTL },
	{ VLV_GPIO_NC_6_HV_DDI1_HPD },
	{ VLV_GPIO_NC_7_HV_DDI1_DDC_SDA },
	{ VLV_GPIO_NC_8_HV_DDI1_DDC_SCL },
	{ VLV_GPIO_NC_9_PANEL1_VDDEN },
	{ VLV_GPIO_NC_10_PANEL1_BKLTEN },
	{ VLV_GPIO_NC_11_PANEL1_BKLTCTL },
};

#define CHV_GPIO_IDX_START_N		0
#define CHV_GPIO_IDX_START_E		73
#define CHV_GPIO_IDX_START_SW		100
#define CHV_GPIO_IDX_START_SE		198

#define CHV_VBT_MAX_PINS_PER_FMLY	15

#define CHV_GPIO_PAD_CFG0(f, i)		(0x4400 + (f) * 0x400 + (i) * 8)
#define  CHV_GPIO_GPIOEN		(1 << 15)
#define  CHV_GPIO_GPIOCFG_GPIO		(0 << 8)
#define  CHV_GPIO_GPIOCFG_GPO		(1 << 8)
#define  CHV_GPIO_GPIOCFG_GPI		(2 << 8)
#define  CHV_GPIO_GPIOCFG_HIZ		(3 << 8)
#define  CHV_GPIO_GPIOTXSTATE(state)	((!!(state)) << 1)

#define CHV_GPIO_PAD_CFG1(f, i)		(0x4400 + (f) * 0x400 + (i) * 8 + 4)
#define  CHV_GPIO_CFGLOCK		(1 << 31)

static inline enum port intel_dsi_seq_port_to_port(u8 port)
{
	return port ? PORT_C : PORT_A;
}

static const u8 *mipi_exec_send_packet(struct intel_dsi *intel_dsi,
				       const u8 *data)
{
	struct mipi_dsi_device *dsi_device;
	u8 type, flags, seq_port;
	u16 len;
	enum port port;

	DRM_DEBUG_KMS("\n");

	flags = *data++;
	type = *data++;

	len = *((u16 *) data);
	data += 2;

	seq_port = (flags >> MIPI_PORT_SHIFT) & 3;

	/* For DSI single link on Port A & C, the seq_port value which is
	 * parsed from Sequence Block#53 of VBT has been set to 0
	 * Now, read/write of packets for the DSI single link on Port A and
	 * Port C will based on the DVO port from VBT block 2.
	 */
	if (intel_dsi->ports == (1 << PORT_C))
		port = PORT_C;
	else
		port = intel_dsi_seq_port_to_port(seq_port);

	dsi_device = intel_dsi->dsi_hosts[port]->device;
	if (!dsi_device) {
		DRM_DEBUG_KMS("no dsi device for port %c\n", port_name(port));
		goto out;
	}

	if ((flags >> MIPI_TRANSFER_MODE_SHIFT) & 1)
		dsi_device->mode_flags &= ~MIPI_DSI_MODE_LPM;
	else
		dsi_device->mode_flags |= MIPI_DSI_MODE_LPM;

	dsi_device->channel = (flags >> MIPI_VIRTUAL_CHANNEL_SHIFT) & 3;

	switch (type) {
	case MIPI_DSI_GENERIC_SHORT_WRITE_0_PARAM:
		mipi_dsi_generic_write(dsi_device, NULL, 0);
		break;
	case MIPI_DSI_GENERIC_SHORT_WRITE_1_PARAM:
		mipi_dsi_generic_write(dsi_device, data, 1);
		break;
	case MIPI_DSI_GENERIC_SHORT_WRITE_2_PARAM:
		mipi_dsi_generic_write(dsi_device, data, 2);
		break;
	case MIPI_DSI_GENERIC_READ_REQUEST_0_PARAM:
	case MIPI_DSI_GENERIC_READ_REQUEST_1_PARAM:
	case MIPI_DSI_GENERIC_READ_REQUEST_2_PARAM:
		DRM_DEBUG_DRIVER("Generic Read not yet implemented or used\n");
		break;
	case MIPI_DSI_GENERIC_LONG_WRITE:
		mipi_dsi_generic_write(dsi_device, data, len);
		break;
	case MIPI_DSI_DCS_SHORT_WRITE:
		mipi_dsi_dcs_write_buffer(dsi_device, data, 1);
		break;
	case MIPI_DSI_DCS_SHORT_WRITE_PARAM:
		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);
		break;
	case MIPI_DSI_DCS_READ:
		DRM_DEBUG_DRIVER("DCS Read not yet implemented or used\n");
		break;
	case MIPI_DSI_DCS_LONG_WRITE:
		mipi_dsi_dcs_write_buffer(dsi_device, data, len);
		break;
	}

out:
	data += len;

	return data;
}

static const u8 *mipi_exec_delay(struct intel_dsi *intel_dsi, const u8 *data)
{
	u32 delay = *((const u32 *) data);

	DRM_DEBUG_KMS("\n");

	usleep_range(delay, delay + 10);
	data += 4;

	return data;
}

static void vlv_exec_gpio(struct drm_i915_private *dev_priv,
			  u8 gpio_source, u8 gpio_index, bool value)
{
	struct gpio_map *map;
	u16 pconf0, padval;
	u32 tmp;
	u8 port;

	if (gpio_index >= ARRAY_SIZE(vlv_gpio_table)) {
		DRM_DEBUG_KMS("unknown gpio index %u\n", gpio_index);
		return;
	}

	map = &vlv_gpio_table[gpio_index];

	if (dev_priv->vbt.dsi.seq_version >= 3) {
		/* XXX: this assumes vlv_gpio_table only has NC GPIOs. */
		port = IOSF_PORT_GPIO_NC;
	} else {
		if (gpio_source == 0) {
			port = IOSF_PORT_GPIO_NC;
		} else if (gpio_source == 1) {
			DRM_DEBUG_KMS("SC gpio not supported\n");
			return;
		} else {
			DRM_DEBUG_KMS("unknown gpio source %u\n", gpio_source);
			return;
		}
	}

	pconf0 = VLV_GPIO_PCONF0(map->base_offset);
	padval = VLV_GPIO_PAD_VAL(map->base_offset);

	mutex_lock(&dev_priv->sb_lock);
	if (!map->init) {
		/* FIXME: remove constant below */
		vlv_iosf_sb_write(dev_priv, port, pconf0, 0x2000CC00);
		map->init = true;
	}

	tmp = 0x4 | value;
	vlv_iosf_sb_write(dev_priv, port, padval, tmp);
	mutex_unlock(&dev_priv->sb_lock);
}

static void chv_exec_gpio(struct drm_i915_private *dev_priv,
			  u8 gpio_source, u8 gpio_index, bool value)
{
	u16 cfg0, cfg1;
	u16 family_num;
	u8 port;

	if (dev_priv->vbt.dsi.seq_version >= 3) {
		if (gpio_index >= CHV_GPIO_IDX_START_SE) {
			/* XXX: it's unclear whether 255->57 is part of SE. */
			gpio_index -= CHV_GPIO_IDX_START_SE;
			port = CHV_IOSF_PORT_GPIO_SE;
		} else if (gpio_index >= CHV_GPIO_IDX_START_SW) {
			gpio_index -= CHV_GPIO_IDX_START_SW;
			port = CHV_IOSF_PORT_GPIO_SW;
		} else if (gpio_index >= CHV_GPIO_IDX_START_E) {
			gpio_index -= CHV_GPIO_IDX_START_E;
			port = CHV_IOSF_PORT_GPIO_E;
		} else {
			port = CHV_IOSF_PORT_GPIO_N;
		}
	} else {
		/* XXX: The spec is unclear about CHV GPIO on seq v2 */
		if (gpio_source != 0) {
			DRM_DEBUG_KMS("unknown gpio source %u\n", gpio_source);
			return;
		}

		if (gpio_index >= CHV_GPIO_IDX_START_E) {
			DRM_DEBUG_KMS("invalid gpio index %u for GPIO N\n",
				      gpio_index);
			return;
		}

		port = CHV_IOSF_PORT_GPIO_N;
	}

	family_num = gpio_index / CHV_VBT_MAX_PINS_PER_FMLY;
	gpio_index = gpio_index % CHV_VBT_MAX_PINS_PER_FMLY;

	cfg0 = CHV_GPIO_PAD_CFG0(family_num, gpio_index);
	cfg1 = CHV_GPIO_PAD_CFG1(family_num, gpio_index);

	mutex_lock(&dev_priv->sb_lock);
	vlv_iosf_sb_write(dev_priv, port, cfg1, 0);
	vlv_iosf_sb_write(dev_priv, port, cfg0,
			  CHV_GPIO_GPIOEN | CHV_GPIO_GPIOCFG_GPO |
			  CHV_GPIO_GPIOTXSTATE(value));
	mutex_unlock(&dev_priv->sb_lock);
}

static const u8 *mipi_exec_gpio(struct intel_dsi *intel_dsi, const u8 *data)
{
	struct drm_device *dev = intel_dsi->base.base.dev;
	struct drm_i915_private *dev_priv = to_i915(dev);
	u8 gpio_source, gpio_index;
	bool value;

	DRM_DEBUG_KMS("\n");

	if (dev_priv->vbt.dsi.seq_version >= 3)
		data++;

	gpio_index = *data++;

	/* gpio source in sequence v2 only */
	if (dev_priv->vbt.dsi.seq_version == 2)
		gpio_source = (*data >> 1) & 3;
	else
		gpio_source = 0;

	/* pull up/down */
	value = *data++ & 1;

	if (IS_VALLEYVIEW(dev_priv))
		vlv_exec_gpio(dev_priv, gpio_source, gpio_index, value);
	else if (IS_CHERRYVIEW(dev_priv))
		chv_exec_gpio(dev_priv, gpio_source, gpio_index, value);
	else
		DRM_DEBUG_KMS("GPIO element not supported on this platform\n");

	return data;
}

static const u8 *mipi_exec_i2c(struct intel_dsi *intel_dsi, const u8 *data)
{
	DRM_DEBUG_KMS("Skipping I2C element execution\n");

	return data + *(data + 6) + 7;
}

static const u8 *mipi_exec_spi(struct intel_dsi *intel_dsi, const u8 *data)
{
	DRM_DEBUG_KMS("Skipping SPI element execution\n");

	return data + *(data + 5) + 6;
}

static const u8 *mipi_exec_pmic(struct intel_dsi *intel_dsi, const u8 *data)
{
	DRM_DEBUG_KMS("Skipping PMIC element execution\n");

	return data + 15;
}

typedef const u8 * (*fn_mipi_elem_exec)(struct intel_dsi *intel_dsi,
					const u8 *data);
static const fn_mipi_elem_exec exec_elem[] = {
	[MIPI_SEQ_ELEM_SEND_PKT] = mipi_exec_send_packet,
	[MIPI_SEQ_ELEM_DELAY] = mipi_exec_delay,
	[MIPI_SEQ_ELEM_GPIO] = mipi_exec_gpio,
	[MIPI_SEQ_ELEM_I2C] = mipi_exec_i2c,
	[MIPI_SEQ_ELEM_SPI] = mipi_exec_spi,
	[MIPI_SEQ_ELEM_PMIC] = mipi_exec_pmic,
};

/*
 * MIPI Sequence from VBT #53 parsing logic
 * We have already separated each seqence during bios parsing
 * Following is generic execution function for any sequence
 */

static const char * const seq_name[] = {
	[MIPI_SEQ_DEASSERT_RESET] = "MIPI_SEQ_DEASSERT_RESET",
	[MIPI_SEQ_INIT_OTP] = "MIPI_SEQ_INIT_OTP",
	[MIPI_SEQ_DISPLAY_ON] = "MIPI_SEQ_DISPLAY_ON",
	[MIPI_SEQ_DISPLAY_OFF]  = "MIPI_SEQ_DISPLAY_OFF",
	[MIPI_SEQ_ASSERT_RESET] = "MIPI_SEQ_ASSERT_RESET",
	[MIPI_SEQ_BACKLIGHT_ON] = "MIPI_SEQ_BACKLIGHT_ON",
	[MIPI_SEQ_BACKLIGHT_OFF] = "MIPI_SEQ_BACKLIGHT_OFF",
	[MIPI_SEQ_TEAR_ON] = "MIPI_SEQ_TEAR_ON",
	[MIPI_SEQ_TEAR_OFF] = "MIPI_SEQ_TEAR_OFF",
	[MIPI_SEQ_POWER_ON] = "MIPI_SEQ_POWER_ON",
	[MIPI_SEQ_POWER_OFF] = "MIPI_SEQ_POWER_OFF",
};

static const char *sequence_name(enum mipi_seq seq_id)
{
	if (seq_id < ARRAY_SIZE(seq_name) && seq_name[seq_id])
		return seq_name[seq_id];
	else
		return "(unknown)";
}

static void generic_exec_sequence(struct drm_panel *panel, enum mipi_seq seq_id)
{
	struct vbt_panel *vbt_panel = to_vbt_panel(panel);
	struct intel_dsi *intel_dsi = vbt_panel->intel_dsi;
	struct drm_i915_private *dev_priv = to_i915(intel_dsi->base.base.dev);
	const u8 *data;
	fn_mipi_elem_exec mipi_elem_exec;

	if (WARN_ON(seq_id >= ARRAY_SIZE(dev_priv->vbt.dsi.sequence)))
		return;

	data = dev_priv->vbt.dsi.sequence[seq_id];
	if (!data)
		return;

	WARN_ON(*data != seq_id);

	DRM_DEBUG_KMS("Starting MIPI sequence %d - %s\n",
		      seq_id, sequence_name(seq_id));

	/* Skip Sequence Byte. */
	data++;

	/* Skip Size of Sequence. */
	if (dev_priv->vbt.dsi.seq_version >= 3)
		data += 4;

	while (1) {
		u8 operation_byte = *data++;
		u8 operation_size = 0;

		if (operation_byte == MIPI_SEQ_ELEM_END)
			break;

		if (operation_byte < ARRAY_SIZE(exec_elem))
			mipi_elem_exec = exec_elem[operation_byte];
		else
			mipi_elem_exec = NULL;

		/* Size of Operation. */
		if (dev_priv->vbt.dsi.seq_version >= 3)
			operation_size = *data++;

		if (mipi_elem_exec) {
			const u8 *next = data + operation_size;

			data = mipi_elem_exec(intel_dsi, data);

			/* Consistency check if we have size. */
			if (operation_size && data != next) {
				DRM_ERROR("Inconsistent operation size\n");
				return;
			}
		} else if (operation_size) {
			/* We have size, skip. */
			DRM_DEBUG_KMS("Unsupported MIPI operation byte %u\n",
				      operation_byte);
			data += operation_size;
		} else {
			/* No size, can't skip without parsing. */
			DRM_ERROR("Unsupported MIPI operation byte %u\n",
				  operation_byte);
			return;
		}
	}
}

static int vbt_panel_prepare(struct drm_panel *panel)
{
	generic_exec_sequence(panel, MIPI_SEQ_ASSERT_RESET);
	generic_exec_sequence(panel, MIPI_SEQ_POWER_ON);
	generic_exec_sequence(panel, MIPI_SEQ_DEASSERT_RESET);
	generic_exec_sequence(panel, MIPI_SEQ_INIT_OTP);

	return 0;
}

static int vbt_panel_unprepare(struct drm_panel *panel)
{
	generic_exec_sequence(panel, MIPI_SEQ_ASSERT_RESET);
	generic_exec_sequence(panel, MIPI_SEQ_POWER_OFF);

	return 0;
}

static int vbt_panel_enable(struct drm_panel *panel)
{
	generic_exec_sequence(panel, MIPI_SEQ_DISPLAY_ON);
	generic_exec_sequence(panel, MIPI_SEQ_BACKLIGHT_ON);

	return 0;
}

static int vbt_panel_disable(struct drm_panel *panel)
{
	generic_exec_sequence(panel, MIPI_SEQ_BACKLIGHT_OFF);
	generic_exec_sequence(panel, MIPI_SEQ_DISPLAY_OFF);

	return 0;
}

static int vbt_panel_get_modes(struct drm_panel *panel)
{
	struct vbt_panel *vbt_panel = to_vbt_panel(panel);
	struct intel_dsi *intel_dsi = vbt_panel->intel_dsi;
	struct drm_device *dev = intel_dsi->base.base.dev;
	struct drm_i915_private *dev_priv = to_i915(dev);
	struct drm_display_mode *mode;

	if (!panel->connector)
		return 0;

	mode = drm_mode_duplicate(dev, dev_priv->vbt.lfp_lvds_vbt_mode);
	if (!mode)
		return 0;

	mode->type |= DRM_MODE_TYPE_PREFERRED;

	drm_mode_probed_add(panel->connector, mode);

	return 1;
}

static const struct drm_panel_funcs vbt_panel_funcs = {
	.disable = vbt_panel_disable,
	.unprepare = vbt_panel_unprepare,
	.prepare = vbt_panel_prepare,
	.enable = vbt_panel_enable,
	.get_modes = vbt_panel_get_modes,
};

struct drm_panel *vbt_panel_init(struct intel_dsi *intel_dsi, u16 panel_id)
{
	struct drm_device *dev = intel_dsi->base.base.dev;
	struct drm_i915_private *dev_priv = to_i915(dev);
	struct mipi_config *mipi_config = dev_priv->vbt.dsi.config;
	struct mipi_pps_data *pps = dev_priv->vbt.dsi.pps;
	struct drm_display_mode *mode = dev_priv->vbt.lfp_lvds_vbt_mode;
	struct vbt_panel *vbt_panel;
	u32 bpp;
	u32 tlpx_ns, extra_byte_count, bitrate, tlpx_ui;
	u32 ui_num, ui_den;
	u32 prepare_cnt, exit_zero_cnt, clk_zero_cnt, trail_cnt;
	u32 ths_prepare_ns, tclk_trail_ns;
	u32 tclk_prepare_clkzero, ths_prepare_hszero;
	u32 lp_to_hs_switch, hs_to_lp_switch;
	u32 pclk, computed_ddr;
	u16 burst_mode_ratio;
	enum port port;

	DRM_DEBUG_KMS("\n");

	intel_dsi->eotp_pkt = mipi_config->eot_pkt_disabled ? 0 : 1;
	intel_dsi->clock_stop = mipi_config->enable_clk_stop ? 1 : 0;
	intel_dsi->lane_count = mipi_config->lane_cnt + 1;
	intel_dsi->pixel_format =
			pixel_format_from_register_bits(
				mipi_config->videomode_color_format << 7);
	bpp = mipi_dsi_pixel_format_to_bpp(intel_dsi->pixel_format);

	intel_dsi->dual_link = mipi_config->dual_link;
	intel_dsi->pixel_overlap = mipi_config->pixel_overlap;
	intel_dsi->operation_mode = mipi_config->is_cmd_mode;
	intel_dsi->video_mode_format = mipi_config->video_transfer_mode;
	intel_dsi->escape_clk_div = mipi_config->byte_clk_sel;
	intel_dsi->lp_rx_timeout = mipi_config->lp_rx_timeout;
	intel_dsi->turn_arnd_val = mipi_config->turn_around_timeout;
	intel_dsi->rst_timer_val = mipi_config->device_reset_timer;
	intel_dsi->init_count = mipi_config->master_init_timer;
	intel_dsi->bw_timer = mipi_config->dbi_bw_timer;
	intel_dsi->video_frmt_cfg_bits =
		mipi_config->bta_enabled ? DISABLE_VIDEO_BTA : 0;

	pclk = mode->clock;

	/* In dual link mode each port needs half of pixel clock */
	if (intel_dsi->dual_link) {
		pclk = pclk / 2;

		/* we can enable pixel_overlap if needed by panel. In this
		 * case we need to increase the pixelclock for extra pixels
		 */
		if (intel_dsi->dual_link == DSI_DUAL_LINK_FRONT_BACK) {
			pclk += DIV_ROUND_UP(mode->vtotal *
						intel_dsi->pixel_overlap *
						60, 1000);
		}
	}

	/* Burst Mode Ratio
	 * Target ddr frequency from VBT / non burst ddr freq
	 * multiply by 100 to preserve remainder
	 */
	if (intel_dsi->video_mode_format == VIDEO_MODE_BURST) {
		if (mipi_config->target_burst_mode_freq) {
			computed_ddr = (pclk * bpp) / intel_dsi->lane_count;

			if (mipi_config->target_burst_mode_freq <
								computed_ddr) {
				DRM_ERROR("Burst mode freq is less than computed\n");
				return NULL;
			}

			burst_mode_ratio = DIV_ROUND_UP(
				mipi_config->target_burst_mode_freq * 100,
				computed_ddr);

			pclk = DIV_ROUND_UP(pclk * burst_mode_ratio, 100);
		} else {
			DRM_ERROR("Burst mode target is not set\n");
			return NULL;
		}
	} else
		burst_mode_ratio = 100;

	intel_dsi->burst_mode_ratio = burst_mode_ratio;
	intel_dsi->pclk = pclk;

	bitrate = (pclk * bpp) / intel_dsi->lane_count;

	switch (intel_dsi->escape_clk_div) {
	case 0:
		tlpx_ns = 50;
		break;
	case 1:
		tlpx_ns = 100;
		break;

	case 2:
		tlpx_ns = 200;
		break;
	default:
		tlpx_ns = 50;
		break;
	}

	switch (intel_dsi->lane_count) {
	case 1:
	case 2:
		extra_byte_count = 2;
		break;
	case 3:
		extra_byte_count = 4;
		break;
	case 4:
	default:
		extra_byte_count = 3;
		break;
	}

	/*
	 * ui(s) = 1/f [f in hz]
	 * ui(ns) = 10^9 / (f*10^6) [f in Mhz] -> 10^3/f(Mhz)
	 */

	/* in Kbps */
	ui_num = NS_KHZ_RATIO;
	ui_den = bitrate;

	tclk_prepare_clkzero = mipi_config->tclk_prepare_clkzero;
	ths_prepare_hszero = mipi_config->ths_prepare_hszero;

	/*
	 * B060
	 * LP byte clock = TLPX/ (8UI)
	 */
	intel_dsi->lp_byte_clk = DIV_ROUND_UP(tlpx_ns * ui_den, 8 * ui_num);

	/* count values in UI = (ns value) * (bitrate / (2 * 10^6))
	 *
	 * Since txddrclkhs_i is 2xUI, all the count values programmed in
	 * DPHY param register are divided by 2
	 *
	 * prepare count
	 */
	ths_prepare_ns = max(mipi_config->ths_prepare,
			     mipi_config->tclk_prepare);
	prepare_cnt = DIV_ROUND_UP(ths_prepare_ns * ui_den, ui_num * 2);

	/* exit zero count */
	exit_zero_cnt = DIV_ROUND_UP(
				(ths_prepare_hszero - ths_prepare_ns) * ui_den,
				ui_num * 2
				);

	/*
	 * Exit zero is unified val ths_zero and ths_exit
	 * minimum value for ths_exit = 110ns
	 * min (exit_zero_cnt * 2) = 110/UI
	 * exit_zero_cnt = 55/UI
	 */
	if (exit_zero_cnt < (55 * ui_den / ui_num) && (55 * ui_den) % ui_num)
		exit_zero_cnt += 1;

	/* clk zero count */
	clk_zero_cnt = DIV_ROUND_UP(
			(tclk_prepare_clkzero -	ths_prepare_ns)
			* ui_den, 2 * ui_num);

	/* trail count */
	tclk_trail_ns = max(mipi_config->tclk_trail, mipi_config->ths_trail);
	trail_cnt = DIV_ROUND_UP(tclk_trail_ns * ui_den, 2 * ui_num);

	if (prepare_cnt > PREPARE_CNT_MAX ||
		exit_zero_cnt > EXIT_ZERO_CNT_MAX ||
		clk_zero_cnt > CLK_ZERO_CNT_MAX ||
		trail_cnt > TRAIL_CNT_MAX)
		DRM_DEBUG_DRIVER("Values crossing maximum limits, restricting to max values\n");

	if (prepare_cnt > PREPARE_CNT_MAX)
		prepare_cnt = PREPARE_CNT_MAX;

	if (exit_zero_cnt > EXIT_ZERO_CNT_MAX)
		exit_zero_cnt = EXIT_ZERO_CNT_MAX;

	if (clk_zero_cnt > CLK_ZERO_CNT_MAX)
		clk_zero_cnt = CLK_ZERO_CNT_MAX;

	if (trail_cnt > TRAIL_CNT_MAX)
		trail_cnt = TRAIL_CNT_MAX;

	/* B080 */
	intel_dsi->dphy_reg = exit_zero_cnt << 24 | trail_cnt << 16 |
						clk_zero_cnt << 8 | prepare_cnt;

	/*
	 * LP to HS switch count = 4TLPX + PREP_COUNT * 2 + EXIT_ZERO_COUNT * 2
	 *					+ 10UI + Extra Byte Count
	 *
	 * HS to LP switch count = THS-TRAIL + 2TLPX + Extra Byte Count
	 * Extra Byte Count is calculated according to number of lanes.
	 * High Low Switch Count is the Max of LP to HS and
	 * HS to LP switch count
	 *
	 */
	tlpx_ui = DIV_ROUND_UP(tlpx_ns * ui_den, ui_num);

	/* B044 */
	/* FIXME:
	 * The comment above does not match with the code */
	lp_to_hs_switch = DIV_ROUND_UP(4 * tlpx_ui + prepare_cnt * 2 +
						exit_zero_cnt * 2 + 10, 8);

	hs_to_lp_switch = DIV_ROUND_UP(mipi_config->ths_trail + 2 * tlpx_ui, 8);

	intel_dsi->hs_to_lp_count = max(lp_to_hs_switch, hs_to_lp_switch);
	intel_dsi->hs_to_lp_count += extra_byte_count;

	/* B088 */
	/* LP -> HS for clock lanes
	 * LP clk sync + LP11 + LP01 + tclk_prepare + tclk_zero +
	 *						extra byte count
	 * 2TPLX + 1TLPX + 1 TPLX(in ns) + prepare_cnt * 2 + clk_zero_cnt *
	 *					2(in UI) + extra byte count
	 * In byteclks = (4TLPX + prepare_cnt * 2 + clk_zero_cnt *2 (in UI)) /
	 *					8 + extra byte count
	 */
	intel_dsi->clk_lp_to_hs_count =
		DIV_ROUND_UP(
			4 * tlpx_ui + prepare_cnt * 2 +
			clk_zero_cnt * 2,
			8);

	intel_dsi->clk_lp_to_hs_count += extra_byte_count;

	/* HS->LP for Clock Lanes
	 * Low Power clock synchronisations + 1Tx byteclk + tclk_trail +
	 *						Extra byte count
	 * 2TLPX + 8UI + (trail_count*2)(in UI) + Extra byte count
	 * In byteclks = (2*TLpx(in UI) + trail_count*2 +8)(in UI)/8 +
	 *						Extra byte count
	 */
	intel_dsi->clk_hs_to_lp_count =
		DIV_ROUND_UP(2 * tlpx_ui + trail_cnt * 2 + 8,
			8);
	intel_dsi->clk_hs_to_lp_count += extra_byte_count;

	DRM_DEBUG_KMS("Eot %s\n", enableddisabled(intel_dsi->eotp_pkt));
	DRM_DEBUG_KMS("Clockstop %s\n", enableddisabled(!intel_dsi->clock_stop));
	DRM_DEBUG_KMS("Mode %s\n", intel_dsi->operation_mode ? "command" : "video");
	if (intel_dsi->dual_link == DSI_DUAL_LINK_FRONT_BACK)
		DRM_DEBUG_KMS("Dual link: DSI_DUAL_LINK_FRONT_BACK\n");
	else if (intel_dsi->dual_link == DSI_DUAL_LINK_PIXEL_ALT)
		DRM_DEBUG_KMS("Dual link: DSI_DUAL_LINK_PIXEL_ALT\n");
	else
		DRM_DEBUG_KMS("Dual link: NONE\n");
	DRM_DEBUG_KMS("Pixel Format %d\n", intel_dsi->pixel_format);
	DRM_DEBUG_KMS("TLPX %d\n", intel_dsi->escape_clk_div);
	DRM_DEBUG_KMS("LP RX Timeout 0x%x\n", intel_dsi->lp_rx_timeout);
	DRM_DEBUG_KMS("Turnaround Timeout 0x%x\n", intel_dsi->turn_arnd_val);
	DRM_DEBUG_KMS("Init Count 0x%x\n", intel_dsi->init_count);
	DRM_DEBUG_KMS("HS to LP Count 0x%x\n", intel_dsi->hs_to_lp_count);
	DRM_DEBUG_KMS("LP Byte Clock %d\n", intel_dsi->lp_byte_clk);
	DRM_DEBUG_KMS("DBI BW Timer 0x%x\n", intel_dsi->bw_timer);
	DRM_DEBUG_KMS("LP to HS Clock Count 0x%x\n", intel_dsi->clk_lp_to_hs_count);
	DRM_DEBUG_KMS("HS to LP Clock Count 0x%x\n", intel_dsi->clk_hs_to_lp_count);
	DRM_DEBUG_KMS("BTA %s\n",
			enableddisabled(!(intel_dsi->video_frmt_cfg_bits & DISABLE_VIDEO_BTA)));

	/* delays in VBT are in unit of 100us, so need to convert
	 * here in ms
	 * Delay (100us) * 100 /1000 = Delay / 10 (ms) */
	intel_dsi->backlight_off_delay = pps->bl_disable_delay / 10;
	intel_dsi->backlight_on_delay = pps->bl_enable_delay / 10;
	intel_dsi->panel_on_delay = pps->panel_on_delay / 10;
	intel_dsi->panel_off_delay = pps->panel_off_delay / 10;
	intel_dsi->panel_pwr_cycle_delay = pps->panel_power_cycle_delay / 10;

	/* This is cheating a bit with the cleanup. */
	vbt_panel = devm_kzalloc(dev->dev, sizeof(*vbt_panel), GFP_KERNEL);
	if (!vbt_panel)
		return NULL;

	vbt_panel->intel_dsi = intel_dsi;
	drm_panel_init(&vbt_panel->panel);
	vbt_panel->panel.funcs = &vbt_panel_funcs;
	drm_panel_add(&vbt_panel->panel);

	/* a regular driver would get the device in probe */
	for_each_dsi_port(port, intel_dsi->ports) {
		mipi_dsi_attach(intel_dsi->dsi_hosts[port]->device);
	}

	return &vbt_panel->panel;
}