| 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 |