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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 | // SPDX-License-Identifier: GPL-2.0-only /* * Copyright (C) 2013 NVIDIA Corporation */ #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 6.9, Table 14, Page 40 of the D-PHY * specification (v1.2) 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; /* * The MIPI D-PHY specification (Section 6.9, v1.2, Table 14, Page 40) * contains this formula as: * * T_HS-TRAIL = max(n * 8 * period, 60 + n * 4 * period) * * 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 period, so this code will * assumes that reverse-direction HS mode is supported and uses n = 4. */ timing->hstrail = max(4 * 8 * period, 60 + 4 * 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 D-PHY specification (v1.2, Section * Section 6.9 "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; } |