include/grlib/canbtrs.h

0001 /* SPDX-License-Identifier: BSD-2-Clause */
0002
0003 /**
0004  * @file
0005  * @ingroup can
0006  * @brief Common CAN baud-rate routines for OCCAN/GRCAN/GRCANFD controllers
0007  */
0008
0009 /*
0010  * Copyright (C) 2019, 2020 Cobham Gaisler AB
0011  *
0012  * Redistribution and use in source and binary forms, with or without
0013  * modification, are permitted provided that the following conditions
0014  * are met:
0015  * 1. Redistributions of source code must retain the above copyright
0016  *    notice, this list of conditions and the following disclaimer.
0017  * 2. Redistributions in binary form must reproduce the above copyright
0018  *    notice, this list of conditions and the following disclaimer in the
0019  *    documentation and/or other materials provided with the distribution.
0020  *
0021  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
0022  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
0023  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
0024  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
0025  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
0026  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
0027  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
0028  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
0029  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
0030  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
0031  * POSSIBILITY OF SUCH DAMAGE.
0032  */
0033
0034 #ifndef __GRLIB_CANBTRS_H__
0035 #define __GRLIB_CANBTRS_H__
0036
0037 /**
0038  * @defgroup can CAN
0039  *
0040  * @ingroup RTEMSBSPsSharedGRLIB
0041  *
0042  * @brief CAN routines shared between OCCAN, GRCAN and GRCANFD controllers
0043  *
0044  * @{
0045  */
0046
0047 #ifdef __cplusplus
0048 extern "C" {
0049 #endif
0050
0051 /* CAN Baud-rate parameters, range of valid parameter values */
0052 struct grlib_canbtrs_ranges {
0053     unsigned int max_scaler;
0054     char has_bpr;
0055     unsigned char divfactor;
0056     unsigned char min_tseg1;
0057     unsigned char max_tseg1;
0058     unsigned char min_tseg2;
0059     unsigned char max_tseg2;
0060 };
0061
0062 struct grlib_canbtrs_timing {
0063     unsigned char scaler;
0064     unsigned char ps1;
0065     unsigned char ps2;
0066     unsigned char rsj;
0067     unsigned char bpr;
0068 };
0069
0070 /* @brief Calculate CAN baud-rate generation parameters from requested baud-rate
0071  *
0072  * @param baud            The CAN baud rate requested
0073  * @param core_hz         Input clock [Hz] to CAN core
0074  * @param sampl_pt        CAN sample point in %, 80 means 80%
0075  * @param br              CAN Baud-rate parameters limitations
0076  * @param[out] timing     result is placed here
0077  *
0078  * @retval 0 Baud-rate parameters sucessfully calculated
0079  * @retval negative Failure to generate parameters with less than 5% error
0080  *   margin from requested baud-rate
0081  */
0082 int grlib_canbtrs_calc_timing(
0083     unsigned int baud,
0084     unsigned int core_hz,
0085     unsigned int sampl_pt,
0086     struct grlib_canbtrs_ranges *br,
0087     struct grlib_canbtrs_timing *timing
0088     );
0089
0090 #ifdef __cplusplus
0091 }
0092 #endif
0093
0094 #endif