1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * Copyright (C) 2013 NVIDIA Corporation
4 * Copyright (C) 2018 Cadence Design Systems Inc.
5 */
6
7 #include <linux/errno.h>
8 #include <linux/export.h>
9 #include <linux/kernel.h>
10 #include <linux/time64.h>
11
12 #include <linux/phy/phy.h>
13 #include <linux/phy/phy-mipi-dphy.h>
14
15 /*
16 * Minimum D-PHY timings based on MIPI D-PHY specification. Derived
17 * from the valid ranges specified in Section 6.9, Table 14, Page 41
18 * of the D-PHY specification (v1.2).
19 */
phy_mipi_dphy_calc_config(unsigned long pixel_clock,unsigned int bpp,unsigned int lanes,unsigned long long hs_clk_rate,struct phy_configure_opts_mipi_dphy * cfg)20 static int phy_mipi_dphy_calc_config(unsigned long pixel_clock,
21 unsigned int bpp,
22 unsigned int lanes,
23 unsigned long long hs_clk_rate,
24 struct phy_configure_opts_mipi_dphy *cfg)
25 {
26 unsigned long long ui;
27
28 if (!cfg)
29 return -EINVAL;
30
31 if (!hs_clk_rate) {
32 hs_clk_rate = pixel_clock * bpp;
33 do_div(hs_clk_rate, lanes);
34 }
35
36 ui = ALIGN(PSEC_PER_SEC, hs_clk_rate);
37 do_div(ui, hs_clk_rate);
38
39 cfg->clk_miss = 0;
40 cfg->clk_post = 60000 + 52 * ui;
41 cfg->clk_pre = 8;
42 cfg->clk_prepare = 38000;
43 cfg->clk_settle = 95000;
44 cfg->clk_term_en = 0;
45 cfg->clk_trail = 60000;
46 cfg->clk_zero = 262000;
47 cfg->d_term_en = 0;
48 cfg->eot = 0;
49 cfg->hs_exit = 100000;
50 cfg->hs_prepare = 40000 + 4 * ui;
51 cfg->hs_zero = 105000 + 6 * ui;
52 cfg->hs_settle = 85000 + 6 * ui;
53 cfg->hs_skip = 40000;
54
55 /*
56 * The MIPI D-PHY specification (Section 6.9, v1.2, Table 14, Page 40)
57 * contains this formula as:
58 *
59 * T_HS-TRAIL = max(n * 8 * ui, 60 + n * 4 * ui)
60 *
61 * where n = 1 for forward-direction HS mode and n = 4 for reverse-
62 * direction HS mode. There's only one setting and this function does
63 * not parameterize on anything other that ui, so this code will
64 * assumes that reverse-direction HS mode is supported and uses n = 4.
65 */
66 cfg->hs_trail = max(4 * 8 * ui, 60000 + 4 * 4 * ui);
67
68 cfg->init = 100;
69 cfg->lpx = 50000;
70 cfg->ta_get = 5 * cfg->lpx;
71 cfg->ta_go = 4 * cfg->lpx;
72 cfg->ta_sure = cfg->lpx;
73 cfg->wakeup = 1000;
74
75 cfg->hs_clk_rate = hs_clk_rate;
76 cfg->lanes = lanes;
77
78 return 0;
79 }
80
phy_mipi_dphy_get_default_config(unsigned long pixel_clock,unsigned int bpp,unsigned int lanes,struct phy_configure_opts_mipi_dphy * cfg)81 int phy_mipi_dphy_get_default_config(unsigned long pixel_clock,
82 unsigned int bpp,
83 unsigned int lanes,
84 struct phy_configure_opts_mipi_dphy *cfg)
85 {
86 return phy_mipi_dphy_calc_config(pixel_clock, bpp, lanes, 0, cfg);
87
88 }
89 EXPORT_SYMBOL(phy_mipi_dphy_get_default_config);
90
phy_mipi_dphy_get_default_config_for_hsclk(unsigned long long hs_clk_rate,unsigned int lanes,struct phy_configure_opts_mipi_dphy * cfg)91 int phy_mipi_dphy_get_default_config_for_hsclk(unsigned long long hs_clk_rate,
92 unsigned int lanes,
93 struct phy_configure_opts_mipi_dphy *cfg)
94 {
95 if (!hs_clk_rate)
96 return -EINVAL;
97
98 return phy_mipi_dphy_calc_config(0, 0, lanes, hs_clk_rate, cfg);
99
100 }
101 EXPORT_SYMBOL(phy_mipi_dphy_get_default_config_for_hsclk);
102
103 /*
104 * Validate D-PHY configuration according to MIPI D-PHY specification
105 * (v1.2, Section Section 6.9 "Global Operation Timing Parameters").
106 */
phy_mipi_dphy_config_validate(struct phy_configure_opts_mipi_dphy * cfg)107 int phy_mipi_dphy_config_validate(struct phy_configure_opts_mipi_dphy *cfg)
108 {
109 unsigned long long ui;
110
111 if (!cfg)
112 return -EINVAL;
113
114 ui = ALIGN(PSEC_PER_SEC, cfg->hs_clk_rate);
115 do_div(ui, cfg->hs_clk_rate);
116
117 if (cfg->clk_miss > 60000)
118 return -EINVAL;
119
120 if (cfg->clk_post < (60000 + 52 * ui))
121 return -EINVAL;
122
123 if (cfg->clk_pre < 8)
124 return -EINVAL;
125
126 if (cfg->clk_prepare < 38000 || cfg->clk_prepare > 95000)
127 return -EINVAL;
128
129 if (cfg->clk_settle < 95000 || cfg->clk_settle > 300000)
130 return -EINVAL;
131
132 if (cfg->clk_term_en > 38000)
133 return -EINVAL;
134
135 if (cfg->clk_trail < 60000)
136 return -EINVAL;
137
138 if ((cfg->clk_prepare + cfg->clk_zero) < 300000)
139 return -EINVAL;
140
141 if (cfg->d_term_en > (35000 + 4 * ui))
142 return -EINVAL;
143
144 if (cfg->eot > (105000 + 12 * ui))
145 return -EINVAL;
146
147 if (cfg->hs_exit < 100000)
148 return -EINVAL;
149
150 if (cfg->hs_prepare < (40000 + 4 * ui) ||
151 cfg->hs_prepare > (85000 + 6 * ui))
152 return -EINVAL;
153
154 if ((cfg->hs_prepare + cfg->hs_zero) < (145000 + 10 * ui))
155 return -EINVAL;
156
157 if ((cfg->hs_settle < (85000 + 6 * ui)) ||
158 (cfg->hs_settle > (145000 + 10 * ui)))
159 return -EINVAL;
160
161 if (cfg->hs_skip < 40000 || cfg->hs_skip > (55000 + 4 * ui))
162 return -EINVAL;
163
164 if (cfg->hs_trail < max(8 * ui, 60000 + 4 * ui))
165 return -EINVAL;
166
167 if (cfg->init < 100)
168 return -EINVAL;
169
170 if (cfg->lpx < 50000)
171 return -EINVAL;
172
173 if (cfg->ta_get != (5 * cfg->lpx))
174 return -EINVAL;
175
176 if (cfg->ta_go != (4 * cfg->lpx))
177 return -EINVAL;
178
179 if (cfg->ta_sure < cfg->lpx || cfg->ta_sure > (2 * cfg->lpx))
180 return -EINVAL;
181
182 if (cfg->wakeup < 1000)
183 return -EINVAL;
184
185 return 0;
186 }
187 EXPORT_SYMBOL(phy_mipi_dphy_config_validate);
188