4d42e3685c
The new driver provides several new features: - asynchronous transfer - transactions (several transfers executed at once) - queueing The style still provides the legacy interface. Change-Id: I6d8ecc89d1f7057847c9b2dc69b76cd45c9c8407
104 lines
4.1 KiB
C
104 lines
4.1 KiB
C
/***************************************************************************
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* __________ __ ___.
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* Open \______ \ ____ ____ | | _\_ |__ _______ ___
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* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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* $Id$
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*
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* Copyright (C) 2011 by Amaury Pouly
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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****************************************************************************/
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#ifndef __I2C_IMX233_H__
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#define __I2C_IMX233_H__
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#include "cpu.h"
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#include "system.h"
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#include "system-target.h"
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enum imx233_i2c_error_t
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{
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I2C_SUCCESS = 0,
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I2C_ERROR = -1,
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I2C_TIMEOUT = -2,
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I2C_MASTER_LOSS = -3,
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I2C_NO_SLAVE_ACK = -4,
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I2C_SLAVE_NAK = -5,
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I2C_BUFFER_FULL = -6,
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I2C_SKIP = -7, /* transfer skipped before of previous error in transaction */
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};
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/** Important notes on the driver.
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*
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* The driver supports both synchronous and asynchronous transfers. Asynchronous
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* transfer functions can safely be called from IRQ context. Beware that the completion
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* callback of asynchronous transfers may be called from IRQ context.
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*
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* The driver supports queuing so it is safe to call several transfer functions
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* concurrently.
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*/
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void imx233_i2c_init(void);
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/** legacy API:
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* read/write functions return 0 on success */
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int i2c_write(int device, const unsigned char* buf, int count);
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int i2c_read(int device, unsigned char* buf, int count);
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int i2c_readmem(int device, int address, unsigned char* buf, int count);
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int i2c_writemem(int device, int address, const unsigned char* buf, int count);
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/** Advanced API */
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struct imx233_i2c_xfer_t;
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typedef void (*imx233_i2c_cb_t)(struct imx233_i2c_xfer_t *xfer, enum imx233_i2c_error_t status);
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/** Transfer mode. There are currently two types of transfers, to make
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* programming simpler:
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* - write: write count[0] bytes from data[0], and then count[1] bytes from data[1]
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* (if count[1] > 0). The second stage is useful to avoid allocating a single
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* buffer to hold address + data for example.
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* - read: write count[0] bytes from data[0], and then read count[1] bytes from data[1].
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* If count[0] = 0 then the write stage is ignored.
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*/
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enum imx233_i2x_xfer_mode_t
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{
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I2C_WRITE,
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I2C_READ,
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};
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/** This data structure represents one transfer. The exact shape of the transfer
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* depends on the mode.
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* NOTE a single transfer is limited to 512 bytes of data (RX + TX)
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* A transaction is made up of several transfers, chained together.
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*/
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struct imx233_i2c_xfer_t
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{
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struct imx233_i2c_xfer_t *next; /* next transfer, or NULL */
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imx233_i2c_cb_t callback; /* NULL for no callack */
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int dev_addr; /* device address */
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bool fast_mode; /* 400 kHz 'fast' mode or 100 kHz 'normal' mode */
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enum imx233_i2x_xfer_mode_t mode; /* transfer mode */
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int count[2]; /* count: depends on mode */
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void *data[2]; /* data: depends on mode */
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unsigned tmo_ms; /* timeout in milliseconds (0 means infinite) */
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/* internal */
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struct imx233_i2c_xfer_t *last; /* last in transaction */
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};
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/* Queue one or more tranfer. If several transfer are queued (transaction)
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* they are guaranteed to be executed "as one" (ie without interleaving). Furthermore,
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* if a transfer of the transfaction fails, the remaining transfers of the transactions
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* will NOT be executed (and their callback will be called with SKIP status).
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* Return 0 if queueing was successful. Note that the transfer may still fail,
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* in which case the callback will have a nonzero status code. */
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void imx233_i2c_transfer(struct imx233_i2c_xfer_t *xfer);
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#endif // __I2C_IMX233_H__
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