1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2017 Ian Lepore <ian@freebsd.org> 5 * 6 * Development sponsored by Microsemi, Inc. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 /* 31 * Helper code to recover a hung i2c bus by bit-banging a recovery sequence. 32 */ 33 34 #ifndef _IICBUS_IIC_RECOVER_BUS_H_ 35 #define _IICBUS_IIC_RECOVER_BUS_H_ 36 37 struct iicrb_pin_access { 38 void *ctx; 39 int (*getsda)(void *ctx); 40 void (*setsda)(void *ctx, int value); 41 int (*getscl)(void *ctx); 42 void (*setscl)(void *ctx, int value); 43 }; 44 45 /* 46 * Drive the bus-recovery logic by manipulating the line states using the 47 * caller-provided functions. This does not block or sleep or acquire any locks 48 * (unless the provided pin access functions do so). It uses DELAY() to pace 49 * bits on the bus. 50 * 51 * Returns 0 if the bus is functioning properly or IIC_EBUSERR if the recovery 52 * attempt failed and some slave device is still driving the bus. 53 */ 54 int iic_recover_bus(struct iicrb_pin_access *pins); 55 56 #endif 57