b897b02c6c
Errors are communicated between the i2c controller layer and upper layers (iicbus and slave device drivers) using a set of IIC_Exxxxxx constants which effectively define a private number space separate from (and having values that conflict with) the system errno number space. Sometimes it is necessary to report a plain old system error (especially EINTR) from the controller or bus layer and have that value make it back across the syscall interface intact. I initially considered replicating a few "crucial" errno values with similar names and new numbers, e.g., IIC_EINTR, IIC_ERESTART, etc. It seemed like that had the potential to grow over time until many of the errno names were duplicated into the IIC_Exxxxx space. So instead, this defines a mechanism to "encode" an errno into the IIC_Exxxx space by setting the high bit and putting the errno into the lower-order bits; a new errno2iic() function does this. The existing iic2errno() recognizes the encoded values and extracts the original errno out of the encoded value. An interesting wrinkle occurs with the pseudo-error values such as ERESTART -- they aleady have the high bit set, and turning it off would be the wrong thing to do. Instead, iic2errno() recognizes that lots of high bits are on (i.e., it's a negative number near to zero) and just returns that value as-is. Thus, existing drivers continue to work without needing any changes, and there is now a way to return errno values from the lower layers. The first use of that is in iicbus_poll() which does mtx_sleep() with the PCATCH flag, and needs to return the errno from that up the call chain. Differential Revision: https://reviews.freebsd.org/D20975
165 lines
5.5 KiB
C
165 lines
5.5 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (c) 1998, 2001 Nicolas Souchu
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#ifndef __IICONF_H
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#define __IICONF_H
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#include <sys/queue.h>
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#include <dev/iicbus/iic.h>
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#define IICPRI (PZERO+8) /* XXX sleep/wakeup queue priority */
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#define LSB 0x1
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/*
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* Options affecting iicbus_request_bus()
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*/
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#define IIC_DONTWAIT 0
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#define IIC_NOINTR 0
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#define IIC_WAIT 0x1
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#define IIC_INTR 0x2
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#define IIC_INTRWAIT (IIC_INTR | IIC_WAIT)
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#define IIC_RECURSIVE 0x4
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/*
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* i2c modes
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*/
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#define IIC_MASTER 0x1
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#define IIC_SLAVE 0x2
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#define IIC_POLLED 0x4
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/*
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* i2c speed
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*/
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#define IIC_UNKNOWN 0x0
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#define IIC_SLOW 0x1
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#define IIC_FAST 0x2
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#define IIC_FASTEST 0x3
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#define IIC_LAST_READ 0x1
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/*
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* callback index
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*/
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#define IIC_REQUEST_BUS 0x1
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#define IIC_RELEASE_BUS 0x2
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/*
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* interrupt events
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*/
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#define INTR_GENERAL 0x1 /* general call received */
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#define INTR_START 0x2 /* the I2C interface is addressed */
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#define INTR_STOP 0x3 /* stop condition received */
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#define INTR_RECEIVE 0x4 /* character received */
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#define INTR_TRANSMIT 0x5 /* character to transmit */
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#define INTR_ERROR 0x6 /* error */
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#define INTR_NOACK 0x7 /* no ack from master receiver */
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/*
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* adapter layer errors
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*/
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#define IIC_NOERR 0x0 /* no error occurred */
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#define IIC_EBUSERR 0x1 /* bus error (hardware not in expected state) */
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#define IIC_ENOACK 0x2 /* ack not received until timeout */
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#define IIC_ETIMEOUT 0x3 /* timeout */
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#define IIC_EBUSBSY 0x4 /* bus busy (reserved by another client) */
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#define IIC_ESTATUS 0x5 /* status error */
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#define IIC_EUNDERFLOW 0x6 /* slave ready for more data */
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#define IIC_EOVERFLOW 0x7 /* too much data */
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#define IIC_ENOTSUPP 0x8 /* request not supported */
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#define IIC_ENOADDR 0x9 /* no address assigned to the interface */
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#define IIC_ERESOURCE 0xa /* resources (memory, whatever) unavailable */
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#define IIC_ERRNO __INT_MIN /* marker bit: errno is in low-order bits */
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/*
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* Note that all iicbus functions return IIC_Exxxxx status values,
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* except iic2errno() (obviously) and iicbus_started() (returns bool).
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*/
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extern int iic2errno(int);
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extern int errno2iic(int);
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extern int iicbus_request_bus(device_t, device_t, int);
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extern int iicbus_release_bus(device_t, device_t);
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extern device_t iicbus_alloc_bus(device_t);
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extern void iicbus_intr(device_t, int, char *);
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extern int iicbus_null_repeated_start(device_t, u_char);
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extern int iicbus_null_callback(device_t, int, caddr_t);
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#define iicbus_reset(bus,speed,addr,oldaddr) \
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(IICBUS_RESET(device_get_parent(bus), speed, addr, oldaddr))
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/* basic I2C operations */
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extern int iicbus_started(device_t);
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extern int iicbus_start(device_t, u_char, int);
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extern int iicbus_stop(device_t);
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extern int iicbus_repeated_start(device_t, u_char, int);
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extern int iicbus_write(device_t, const char *, int, int *, int);
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extern int iicbus_read(device_t, char *, int, int *, int, int);
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/* single byte read/write functions, start/stop not managed */
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extern int iicbus_write_byte(device_t, char, int);
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extern int iicbus_read_byte(device_t, char *, int);
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/* Read/write operations with start/stop conditions managed */
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extern int iicbus_block_write(device_t, u_char, char *, int, int *);
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extern int iicbus_block_read(device_t, u_char, char *, int, int *);
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/* vectors of iic operations to pass to bridge */
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int iicbus_transfer(device_t bus, struct iic_msg *msgs, uint32_t nmsgs);
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int iicbus_transfer_excl(device_t bus, struct iic_msg *msgs, uint32_t nmsgs,
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int how);
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int iicbus_transfer_gen(device_t bus, struct iic_msg *msgs, uint32_t nmsgs);
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/*
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* Simple register read/write routines, but the "register" can be any size.
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* The transfers are done with iicbus_transfer_excl(). Reads use a repeat-start
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* between sending the address and reading; writes use a single start/stop.
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*/
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int iicdev_readfrom(device_t _slavedev, uint8_t _regaddr, void *_buffer,
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uint16_t _buflen, int _waithow);
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int iicdev_writeto(device_t _slavedev, uint8_t _regaddr, void *_buffer,
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uint16_t _buflen, int _waithow);
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#define IICBUS_MODVER 1
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#define IICBUS_MINVER 1
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#define IICBUS_MAXVER 1
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#define IICBUS_PREFVER IICBUS_MODVER
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extern driver_t iicbb_driver;
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extern devclass_t iicbb_devclass;
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#define IICBB_MODVER 1
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#define IICBB_MINVER 1
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#define IICBB_MAXVER 1
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#define IICBB_PREFVER IICBB_MODVER
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#endif
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