1 /*- 2 * Copyright (c) 2017 Ian Lepore <ian@freebsd.org> 3 * All rights reserved. 4 * 5 * Development sponsored by Microsemi, Inc. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 * 28 * $FreeBSD$ 29 */ 30 31 /* 32 * Helper code to recover a hung i2c bus by bit-banging a recovery sequence. 33 */ 34 35 #ifndef _IICBUS_IIC_RECOVER_BUS_H_ 36 #define _IICBUS_IIC_RECOVER_BUS_H_ 37 38 struct iicrb_pin_access { 39 void *ctx; 40 int (*getsda)(void *ctx); 41 void (*setsda)(void *ctx, int value); 42 int (*getscl)(void *ctx); 43 void (*setscl)(void *ctx, int value); 44 }; 45 46 /* 47 * Drive the bus-recovery logic by manipulating the line states using the 48 * caller-provided functions. This does not block or sleep or acquire any locks 49 * (unless the provided pin access functions do so). It uses DELAY() to pace 50 * bits on the bus. 51 * 52 * Returns 0 if the bus is functioning properly or IIC_EBUSERR if the recovery 53 * attempt failed and some slave device is still driving the bus. 54 */ 55 int iic_recover_bus(struct iicrb_pin_access *pins); 56 57 #endif 58