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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Copyright (C) 2013 NVIDIA Corporation4 */5 6#include <linux/errno.h>7#include <linux/kernel.h>8 9#include "mipi-phy.h"10 11/*12 * Default D-PHY timings based on MIPI D-PHY specification. Derived from the13 * valid ranges specified in Section 6.9, Table 14, Page 40 of the D-PHY14 * specification (v1.2) with minor adjustments.15 */16int mipi_dphy_timing_get_default(struct mipi_dphy_timing *timing,17 unsigned long period)18{19 timing->clkmiss = 0;20 timing->clkpost = 70 + 52 * period;21 timing->clkpre = 8;22 timing->clkprepare = 65;23 timing->clksettle = 95;24 timing->clktermen = 0;25 timing->clktrail = 80;26 timing->clkzero = 260;27 timing->dtermen = 0;28 timing->eot = 0;29 timing->hsexit = 120;30 timing->hsprepare = 65 + 5 * period;31 timing->hszero = 145 + 5 * period;32 timing->hssettle = 85 + 6 * period;33 timing->hsskip = 40;34 35 /*36 * The MIPI D-PHY specification (Section 6.9, v1.2, Table 14, Page 40)37 * contains this formula as:38 *39 * T_HS-TRAIL = max(n * 8 * period, 60 + n * 4 * period)40 *41 * where n = 1 for forward-direction HS mode and n = 4 for reverse-42 * direction HS mode. There's only one setting and this function does43 * not parameterize on anything other that period, so this code will44 * assumes that reverse-direction HS mode is supported and uses n = 4.45 */46 timing->hstrail = max(4 * 8 * period, 60 + 4 * 4 * period);47 48 timing->init = 100000;49 timing->lpx = 60;50 timing->taget = 5 * timing->lpx;51 timing->tago = 4 * timing->lpx;52 timing->tasure = 2 * timing->lpx;53 timing->wakeup = 1000000;54 55 return 0;56}57 58/*59 * Validate D-PHY timing according to MIPI D-PHY specification (v1.2, Section60 * Section 6.9 "Global Operation Timing Parameters").61 */62int mipi_dphy_timing_validate(struct mipi_dphy_timing *timing,63 unsigned long period)64{65 if (timing->clkmiss > 60)66 return -EINVAL;67 68 if (timing->clkpost < (60 + 52 * period))69 return -EINVAL;70 71 if (timing->clkpre < 8)72 return -EINVAL;73 74 if (timing->clkprepare < 38 || timing->clkprepare > 95)75 return -EINVAL;76 77 if (timing->clksettle < 95 || timing->clksettle > 300)78 return -EINVAL;79 80 if (timing->clktermen > 38)81 return -EINVAL;82 83 if (timing->clktrail < 60)84 return -EINVAL;85 86 if (timing->clkprepare + timing->clkzero < 300)87 return -EINVAL;88 89 if (timing->dtermen > 35 + 4 * period)90 return -EINVAL;91 92 if (timing->eot > 105 + 12 * period)93 return -EINVAL;94 95 if (timing->hsexit < 100)96 return -EINVAL;97 98 if (timing->hsprepare < 40 + 4 * period ||99 timing->hsprepare > 85 + 6 * period)100 return -EINVAL;101 102 if (timing->hsprepare + timing->hszero < 145 + 10 * period)103 return -EINVAL;104 105 if ((timing->hssettle < 85 + 6 * period) ||106 (timing->hssettle > 145 + 10 * period))107 return -EINVAL;108 109 if (timing->hsskip < 40 || timing->hsskip > 55 + 4 * period)110 return -EINVAL;111 112 if (timing->hstrail < max(8 * period, 60 + 4 * period))113 return -EINVAL;114 115 if (timing->init < 100000)116 return -EINVAL;117 118 if (timing->lpx < 50)119 return -EINVAL;120 121 if (timing->taget != 5 * timing->lpx)122 return -EINVAL;123 124 if (timing->tago != 4 * timing->lpx)125 return -EINVAL;126 127 if (timing->tasure < timing->lpx || timing->tasure > 2 * timing->lpx)128 return -EINVAL;129 130 if (timing->wakeup < 1000000)131 return -EINVAL;132 133 return 0;134}135