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/*
ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
2011,2012 Giovanni Di Sirio.
This file is part of ChibiOS/RT.
ChibiOS/RT is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
ChibiOS/RT is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
---
A special exception to the GPL can be applied should you wish to distribute
a combined work that includes ChibiOS/RT, without being obliged to provide
the source code for any proprietary components. See the file exception.txt
for full details of how and when the exception can be applied.
*/
/*
Concepts and parts of this file have been contributed by Uladzimir Pylinsky
aka barthess.
*/
/**
* @file i2c.c
* @brief I2C Driver code.
*
* @addtogroup I2C
* @{
*/
#include "ch.h"
#include "hal.h"
#if HAL_USE_I2C || defined(__DOXYGEN__)
/*===========================================================================*/
/* Driver local definitions. */
/*===========================================================================*/
/*===========================================================================*/
/* Driver exported variables. */
/*===========================================================================*/
/*===========================================================================*/
/* Driver local variables. */
/*===========================================================================*/
/*===========================================================================*/
/* Driver local functions. */
/*===========================================================================*/
/*===========================================================================*/
/* Driver exported functions. */
/*===========================================================================*/
/**
* @brief I2C Driver initialization.
* @note This function is implicitly invoked by @p halInit(), there is
* no need to explicitly initialize the driver.
*
* @init
*/
void i2cInit(void) {
i2c_lld_init();
}
/**
* @brief Initializes the standard part of a @p I2CDriver structure.
*
* @param[out] i2cp pointer to the @p I2CDriver object
*
* @init
*/
void i2cObjectInit(I2CDriver *i2cp) {
i2cp->state = I2C_STOP;
i2cp->config = NULL;
#if I2C_USE_MUTUAL_EXCLUSION
#if CH_USE_MUTEXES
chMtxInit(&i2cp->mutex);
#else
chSemInit(&i2cp->semaphore, 1);
#endif /* CH_USE_MUTEXES */
#endif /* I2C_USE_MUTUAL_EXCLUSION */
#if defined(I2C_DRIVER_EXT_INIT_HOOK)
I2C_DRIVER_EXT_INIT_HOOK(i2cp);
#endif
}
/**
* @brief Configures and activates the I2C peripheral.
*
* @param[in] i2cp pointer to the @p I2CDriver object
* @param[in] config pointer to the @p I2CConfig object
*
* @api
*/
void i2cStart(I2CDriver *i2cp, const I2CConfig *config) {
chDbgCheck((i2cp != NULL) && (config != NULL), "i2cStart");
chDbgAssert((i2cp->state == I2C_STOP) || (i2cp->state == I2C_READY) ||
(i2cp->state == I2C_LOCKED),
"i2cStart(), #1",
"invalid state");
chSysLock();
i2cp->config = config;
i2c_lld_start(i2cp);
i2cp->state = I2C_READY;
chSysUnlock();
}
/**
* @brief Deactivates the I2C peripheral.
*
* @param[in] i2cp pointer to the @p I2CDriver object
*
* @api
*/
void i2cStop(I2CDriver *i2cp) {
chDbgCheck(i2cp != NULL, "i2cStop");
chDbgAssert((i2cp->state == I2C_STOP) || (i2cp->state == I2C_READY) ||
(i2cp->state == I2C_LOCKED),
"i2cStop(), #1",
"invalid state");
chSysLock();
i2c_lld_stop(i2cp);
i2cp->state = I2C_STOP;
chSysUnlock();
}
/**
* @brief Returns the errors mask associated to the previous operation.
*
* @param[in] i2cp pointer to the @p I2CDriver object
* @return The errors mask.
*
* @api
*/
i2cflags_t i2cGetErrors(I2CDriver *i2cp) {
chDbgCheck(i2cp != NULL, "i2cGetErrors");
return i2c_lld_get_errors(i2cp);
}
/**
* @brief Sends data via the I2C bus.
* @details Function designed to realize "read-through-write" transfer
* paradigm. If you want transmit data without any further read,
* than set @b rxbytes field to 0.
*
* @param[in] i2cp pointer to the @p I2CDriver object
* @param[in] addr slave device address (7 bits) without R/W bit
* @param[in] txbuf pointer to transmit buffer
* @param[in] txbytes number of bytes to be transmitted
* @param[out] rxbuf pointer to receive buffer
* @param[in] rxbytes number of bytes to be received, set it to 0 if
* you want transmit only
* @param[in] timeout the number of ticks before the operation timeouts,
* the following special values are allowed:
* - @a TIME_INFINITE no timeout.
* .
*
* @return The operation status.
* @retval RDY_OK if the function succeeded.
* @retval RDY_RESET if one or more I2C errors occurred, the errors can
* be retrieved using @p i2cGetErrors().
* @retval RDY_TIMEOUT if a timeout occurred before operation end.
*
* @api
*/
msg_t i2cMasterTransmitTimeout(I2CDriver *i2cp,
i2caddr_t addr,
const uint8_t *txbuf,
size_t txbytes,
uint8_t *rxbuf,
size_t rxbytes,
systime_t timeout) {
msg_t rdymsg;
chDbgCheck((i2cp != NULL) && (addr != 0) &&
(txbytes > 0) && (txbuf != NULL) &&
((rxbytes == 0) || ((rxbytes > 0) && (rxbuf != NULL))) &&
(timeout != TIME_IMMEDIATE),
"i2cMasterTransmitTimeout");
chDbgAssert(i2cp->state == I2C_READY,
"i2cMasterTransmitTimeout(), #1", "not ready");
chSysLock();
i2cp->errors = I2CD_NO_ERROR;
i2cp->state = I2C_ACTIVE_TX;
rdymsg = i2c_lld_master_transmit_timeout(i2cp, addr, txbuf, txbytes,
rxbuf, rxbytes, timeout);
if (rdymsg == RDY_TIMEOUT)
i2cp->state = I2C_LOCKED;
else
i2cp->state = I2C_READY;
chSysUnlock();
return rdymsg;
}
/**
* @brief Receives data from the I2C bus.
*
* @param[in] i2cp pointer to the @p I2CDriver object
* @param[in] addr slave device address (7 bits) without R/W bit
* @param[out] rxbuf pointer to receive buffer
* @param[in] rxbytes number of bytes to be received
* @param[in] timeout the number of ticks before the operation timeouts,
* the following special values are allowed:
* - @a TIME_INFINITE no timeout.
* .
*
* @return The operation status.
* @retval RDY_OK if the function succeeded.
* @retval RDY_RESET if one or more I2C errors occurred, the errors can
* be retrieved using @p i2cGetErrors().
* @retval RDY_TIMEOUT if a timeout occurred before operation end.
*
* @api
*/
msg_t i2cMasterReceiveTimeout(I2CDriver *i2cp,
i2caddr_t addr,
uint8_t *rxbuf,
size_t rxbytes,
systime_t timeout){
msg_t rdymsg;
chDbgCheck((i2cp != NULL) && (addr != 0) &&
(rxbytes > 0) && (rxbuf != NULL) &&
(timeout != TIME_IMMEDIATE),
"i2cMasterReceiveTimeout");
chDbgAssert(i2cp->state == I2C_READY,
"i2cMasterReceive(), #1", "not ready");
chSysLock();
i2cp->errors = I2CD_NO_ERROR;
i2cp->state = I2C_ACTIVE_RX;
rdymsg = i2c_lld_master_receive_timeout(i2cp, addr, rxbuf, rxbytes, timeout);
if (rdymsg == RDY_TIMEOUT)
i2cp->state = I2C_LOCKED;
else
i2cp->state = I2C_READY;
chSysUnlock();
return rdymsg;
}
#if I2C_USE_MUTUAL_EXCLUSION || defined(__DOXYGEN__)
/**
* @brief Gains exclusive access to the I2C bus.
* @details This function tries to gain ownership to the SPI bus, if the bus
* is already being used then the invoking thread is queued.
* @pre In order to use this function the option @p I2C_USE_MUTUAL_EXCLUSION
* must be enabled.
*
* @param[in] i2cp pointer to the @p I2CDriver object
*
* @api
*/
void i2cAcquireBus(I2CDriver *i2cp) {
chDbgCheck(i2cp != NULL, "i2cAcquireBus");
#if CH_USE_MUTEXES
chMtxLock(&i2cp->mutex);
#elif CH_USE_SEMAPHORES
chSemWait(&i2cp->semaphore);
#endif
}
/**
* @brief Releases exclusive access to the I2C bus.
* @pre In order to use this function the option @p I2C_USE_MUTUAL_EXCLUSION
* must be enabled.
*
* @param[in] i2cp pointer to the @p I2CDriver object
*
* @api
*/
void i2cReleaseBus(I2CDriver *i2cp) {
chDbgCheck(i2cp != NULL, "i2cReleaseBus");
#if CH_USE_MUTEXES
chMtxUnlock();
#elif CH_USE_SEMAPHORES
chSemSignal(&i2cp->semaphore);
#endif
}
#endif /* I2C_USE_MUTUAL_EXCLUSION */
#endif /* HAL_USE_I2C */
/** @} */
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