summaryrefslogtreecommitdiffstats
path: root/drivers/phy/phy-core-mipi-dphy.c
blob: 14e0551cd3190f71aeb85f0318c3d71c455836de (plain) (blame)
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
/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Copyright (C) 2013 NVIDIA Corporation
 * Copyright (C) 2018 Cadence Design Systems Inc.
 */

#include <linux/errno.h>
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/time64.h>

#include <linux/phy/phy.h>
#include <linux/phy/phy-mipi-dphy.h>

#define PSEC_PER_SEC	1000000000000LL

/*
 * Minimum D-PHY timings based on MIPI D-PHY specification. Derived
 * from the valid ranges specified in Section 6.9, Table 14, Page 41
 * of the D-PHY specification (v2.1).
 */
int phy_mipi_dphy_get_default_config(unsigned long pixel_clock,
				     unsigned int bpp,
				     unsigned int lanes,
				     struct phy_configure_opts_mipi_dphy *cfg)
{
	unsigned long long hs_clk_rate;
	unsigned long long ui;

	if (!cfg)
		return -EINVAL;

	hs_clk_rate = pixel_clock * bpp;
	do_div(hs_clk_rate, lanes);

	ui = ALIGN(PSEC_PER_SEC, hs_clk_rate);
	do_div(ui, hs_clk_rate);

	cfg->clk_miss = 0;
	cfg->clk_post = 60000 + 52 * ui;
	cfg->clk_pre = 8000;
	cfg->clk_prepare = 38000;
	cfg->clk_settle = 95000;
	cfg->clk_term_en = 0;
	cfg->clk_trail = 60000;
	cfg->clk_zero = 262000;
	cfg->d_term_en = 0;
	cfg->eot = 0;
	cfg->hs_exit = 100000;
	cfg->hs_prepare = 40000 + 4 * ui;
	cfg->hs_zero = 105000 + 6 * ui;
	cfg->hs_settle = 85000 + 6 * ui;
	cfg->hs_skip = 40000;

	/*
	 * The MIPI D-PHY specification (Section 6.9, v1.2, Table 14, Page 40)
	 * contains this formula as:
	 *
	 *     T_HS-TRAIL = max(n * 8 * ui, 60 + n * 4 * ui)
	 *
	 * where n = 1 for forward-direction HS mode and n = 4 for reverse-
	 * direction HS mode. There's only one setting and this function does
	 * not parameterize on anything other that ui, so this code will
	 * assumes that reverse-direction HS mode is supported and uses n = 4.
	 */
	cfg->hs_trail = max(4 * 8 * ui, 60000 + 4 * 4 * ui);

	cfg->init = 100;
	cfg->lpx = 60000;
	cfg->ta_get = 5 * cfg->lpx;
	cfg->ta_go = 4 * cfg->lpx;
	cfg->ta_sure = 2 * cfg->lpx;
	cfg->wakeup = 1000;

	cfg->hs_clk_rate = hs_clk_rate;
	cfg->lanes = lanes;

	return 0;
}
EXPORT_SYMBOL(phy_mipi_dphy_get_default_config);

/*
 * Validate D-PHY configuration according to MIPI D-PHY specification
 * (v1.2, Section Section 6.9 "Global Operation Timing Parameters").
 */
int phy_mipi_dphy_config_validate(struct phy_configure_opts_mipi_dphy *cfg)
{
	unsigned long long ui;

	if (!cfg)
		return -EINVAL;

	ui = ALIGN(PSEC_PER_SEC, cfg->hs_clk_rate);
	do_div(ui, cfg->hs_clk_rate);

	if (cfg->clk_miss > 60000)
		return -EINVAL;

	if (cfg->clk_post < (60000 + 52 * ui))
		return -EINVAL;

	if (cfg->clk_pre < 8000)
		return -EINVAL;

	if (cfg->clk_prepare < 38000 || cfg->clk_prepare > 95000)
		return -EINVAL;

	if (cfg->clk_settle < 95000 || cfg->clk_settle > 300000)
		return -EINVAL;

	if (cfg->clk_term_en > 38000)
		return -EINVAL;

	if (cfg->clk_trail < 60000)
		return -EINVAL;

	if ((cfg->clk_prepare + cfg->clk_zero) < 300000)
		return -EINVAL;

	if (cfg->d_term_en > (35000 + 4 * ui))
		return -EINVAL;

	if (cfg->eot > (105000 + 12 * ui))
		return -EINVAL;

	if (cfg->hs_exit < 100000)
		return -EINVAL;

	if (cfg->hs_prepare < (40000 + 4 * ui) ||
	    cfg->hs_prepare > (85000 + 6 * ui))
		return -EINVAL;

	if ((cfg->hs_prepare + cfg->hs_zero) < (145000 + 10 * ui))
		return -EINVAL;

	if ((cfg->hs_settle < (85000 + 6 * ui)) ||
	    (cfg->hs_settle > (145000 + 10 * ui)))
		return -EINVAL;

	if (cfg->hs_skip < 40000 || cfg->hs_skip > (55000 + 4 * ui))
		return -EINVAL;

	if (cfg->hs_trail < max(8 * ui, 60000 + 4 * ui))
		return -EINVAL;

	if (cfg->init < 100)
		return -EINVAL;

	if (cfg->lpx < 50000)
		return -EINVAL;

	if (cfg->ta_get != (5 * cfg->lpx))
		return -EINVAL;

	if (cfg->ta_go != (4 * cfg->lpx))
		return -EINVAL;

	if (cfg->ta_sure < cfg->lpx || cfg->ta_sure > (2 * cfg->lpx))
		return -EINVAL;

	if (cfg->wakeup < 1000)
		return -EINVAL;

	return 0;
}
EXPORT_SYMBOL(phy_mipi_dphy_config_validate);