2 * SPDX-License-Identifier: BSD-2-Clause
4 * Copyright (c) 2017 Ian Lepore <ian@freebsd.org>
6 * Development sponsored by Microsemi, Inc.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
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.
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
33 * Helper code to recover a hung i2c bus by bit-banging a recovery sequence.
36 #ifndef _IICBUS_IIC_RECOVER_BUS_H_
37 #define _IICBUS_IIC_RECOVER_BUS_H_
39 struct iicrb_pin_access {
41 int (*getsda)(void *ctx);
42 void (*setsda)(void *ctx, int value);
43 int (*getscl)(void *ctx);
44 void (*setscl)(void *ctx, int value);
48 * Drive the bus-recovery logic by manipulating the line states using the
49 * caller-provided functions. This does not block or sleep or acquire any locks
50 * (unless the provided pin access functions do so). It uses DELAY() to pace
53 * Returns 0 if the bus is functioning properly or IIC_EBUSERR if the recovery
54 * attempt failed and some slave device is still driving the bus.
56 int iic_recover_bus(struct iicrb_pin_access *pins);