summaryrefslogtreecommitdiff
path: root/drivers/gpu/drm/tegra/mipi-phy.c
blob: e2c4aedaee7887b876db279e3c83888ea98f153a (plain)
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
/*
 * Copyright (C) 2013 NVIDIA Corporation
 *
 * Permission to use, copy, modify, distribute, and sell this software and its
 * documentation for any purpose is hereby granted without fee, provided that
 * the above copyright notice appear in all copies and that both that copyright
 * notice and this permission notice appear in supporting documentation, and
 * that the name of the copyright holders not be used in advertising or
 * publicity pertaining to distribution of the software without specific,
 * written prior permission.  The copyright holders make no representations
 * about the suitability of this software for any purpose.  It is provided "as
 * is" without express or implied warranty.
 *
 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
 * OF THIS SOFTWARE.
 */

#include <linux/errno.h>
#include <linux/kernel.h>

#include "mipi-phy.h"

/*
 * Default D-PHY timings based on MIPI D-PHY specification. Derived from
 * the valid ranges specified in Section 5.9 of the D-PHY specification
 * with minor adjustments.
 */
int mipi_dphy_timing_get_default(struct mipi_dphy_timing *timing,
				 unsigned long period)
{
	timing->clkmiss = 0;
	timing->clkpost = 70 + 52 * period;
	timing->clkpre = 8;
	timing->clkprepare = 65;
	timing->clksettle = 95;
	timing->clktermen = 0;
	timing->clktrail = 80;
	timing->clkzero = 260;
	timing->dtermen = 0;
	timing->eot = 0;
	timing->hsexit = 120;
	timing->hsprepare = 65 + 5 * period;
	timing->hszero = 145 + 5 * period;
	timing->hssettle = 85 + 6 * period;
	timing->hsskip = 40;
	timing->hstrail = max(8 * period, 60 + 4 * period);
	timing->init = 100000;
	timing->lpx = 60;
	timing->taget = 5 * timing->lpx;
	timing->tago = 4 * timing->lpx;
	timing->tasure = 2 * timing->lpx;
	timing->wakeup = 1000000;

	return 0;
}

/*
 * Validate D-PHY timing according to MIPI Alliance Specification for D-PHY,
 * Section 5.9 "Global Operation Timing Parameters".
 */
int mipi_dphy_timing_validate(struct mipi_dphy_timing *timing,
			      unsigned long period)
{
	if (timing->clkmiss > 60)
		return -EINVAL;

	if (timing->clkpost < (60 + 52 * period))
		return -EINVAL;

	if (timing->clkpre < 8)
		return -EINVAL;

	if (timing->clkprepare < 38 || timing->clkprepare > 95)
		return -EINVAL;

	if (timing->clksettle < 95 || timing->clksettle > 300)
		return -EINVAL;

	if (timing->clktermen > 38)
		return -EINVAL;

	if (timing->clktrail < 60)
		return -EINVAL;

	if (timing->clkprepare + timing->clkzero < 300)
		return -EINVAL;

	if (timing->dtermen > 35 + 4 * period)
		return -EINVAL;

	if (timing->eot > 105 + 12 * period)
		return -EINVAL;

	if (timing->hsexit < 100)
		return -EINVAL;

	if (timing->hsprepare < 40 + 4 * period ||
	    timing->hsprepare > 85 + 6 * period)
		return -EINVAL;

	if (timing->hsprepare + timing->hszero < 145 + 10 * period)
		return -EINVAL;

	if ((timing->hssettle < 85 + 6 * period) ||
	    (timing->hssettle > 145 + 10 * period))
		return -EINVAL;

	if (timing->hsskip < 40 || timing->hsskip > 55 + 4 * period)
		return -EINVAL;

	if (timing->hstrail < max(8 * period, 60 + 4 * period))
		return -EINVAL;

	if (timing->init < 100000)
		return -EINVAL;

	if (timing->lpx < 50)
		return -EINVAL;

	if (timing->taget != 5 * timing->lpx)
		return -EINVAL;

	if (timing->tago != 4 * timing->lpx)
		return -EINVAL;

	if (timing->tasure < timing->lpx || timing->tasure > 2 * timing->lpx)
		return -EINVAL;

	if (timing->wakeup < 1000000)
		return -EINVAL;

	return 0;
}