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 */ 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 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 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 */ 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