osd-contiki/cpu/cc2538/dev/i2c.c
2015-04-29 11:07:59 +02:00

255 lines
8.3 KiB
C

/*
* Copyright (c) 2015, Mehdi Migault
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. Neither the name of the copyright holder nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* \addtogroup cc2538-i2c cc2538 I2C Control
* @{
*
* \file
* Implementation file of the I2C Control module
*
* \author
* Mehdi Migault
*/
#include "i2c.h"
#include <stdint.h>
#include "clock.h"
/*---------------------------------------------------------------------------*/
/* Additional functions */
static uint32_t
get_sys_clock(void)
{
/* Get the clock status diviser */
return SYS_CTRL_32MHZ /
(1 << (REG(SYS_CTRL_CLOCK_STA) & SYS_CTRL_CLOCK_STA_SYS_DIV));
}
/*---------------------------------------------------------------------------*/
void
i2c_init(uint8_t port_sda, uint8_t pin_sda, uint8_t port_scl, uint8_t pin_scl,
uint32_t bus_speed)
{
/* Enable I2C clock in different modes */
REG(SYS_CTRL_RCGCI2C) |= 1; /* Run mode */
/* Reset I2C peripheral */
REG(SYS_CTRL_SRI2C) |= 1; /* Reset position */
/* Delay for a little bit */
clock_delay_usec(50);
REG(SYS_CTRL_SRI2C) &= ~1; /* Normal position */
/* Set pins in input */
GPIO_SET_INPUT(GPIO_PORT_TO_BASE(port_sda), GPIO_PIN_MASK(pin_sda));
GPIO_SET_INPUT(GPIO_PORT_TO_BASE(port_scl), GPIO_PIN_MASK(pin_scl));
/* Set peripheral control for the pins */
GPIO_PERIPHERAL_CONTROL(GPIO_PORT_TO_BASE(port_sda), GPIO_PIN_MASK(pin_sda));
GPIO_PERIPHERAL_CONTROL(GPIO_PORT_TO_BASE(port_scl), GPIO_PIN_MASK(pin_scl));
/* Set the pad to no drive type */
ioc_set_over(port_sda, pin_sda, IOC_OVERRIDE_DIS);
ioc_set_over(port_scl, pin_scl, IOC_OVERRIDE_DIS);
/* Set pins as peripheral inputs */
REG(IOC_I2CMSSDA) = ioc_input_sel(port_sda, pin_sda);
REG(IOC_I2CMSSCL) = ioc_input_sel(port_scl, pin_scl);
/* Set pins as peripheral outputs */
ioc_set_sel(port_sda, pin_sda, IOC_PXX_SEL_I2C_CMSSDA);
ioc_set_sel(port_scl, pin_scl, IOC_PXX_SEL_I2C_CMSSCL);
/* Enable the I2C master module */
i2c_master_enable();
/* t the master clock frequency */
i2c_set_frequency(bus_speed);
}
/*---------------------------------------------------------------------------*/
void
i2c_master_enable(void)
{
REG(I2CM_CR) |= 0x10; /* Set MFE bit */
}
/*---------------------------------------------------------------------------*/
void
i2c_master_disable(void)
{
REG(I2CM_CR) &= ~0x10; /* Reset MFE bit */
}
/*---------------------------------------------------------------------------*/
void
i2c_set_frequency(uint32_t freq)
{
/* Peripheral clock setting, using the system clock */
REG(I2CM_TPR) = ((get_sys_clock() + (2 * 10 * freq) - 1) /
(2 * 10 * freq)) - 1;
}
/*---------------------------------------------------------------------------*/
void
i2c_master_set_slave_address(uint8_t slave_addr, uint8_t access_mode)
{
if(access_mode) {
REG(I2CM_SA) = ((slave_addr << 1) | 1);
} else {
REG(I2CM_SA) = (slave_addr << 1);
}
}
/*---------------------------------------------------------------------------*/
void
i2c_master_data_put(uint8_t data)
{
REG(I2CM_DR) = data;
}
/*---------------------------------------------------------------------------*/
uint8_t
i2c_master_data_get(void)
{
return REG(I2CM_DR);
}
/*---------------------------------------------------------------------------*/
void
i2c_master_command(uint8_t cmd)
{
REG(I2CM_CTRL) = cmd;
/* Here we need a delay, otherwise the I2C module keep the receiver mode */
clock_delay_usec(1);
}
/*---------------------------------------------------------------------------*/
uint8_t
i2c_master_busy(void)
{
return REG(I2CM_STAT) & I2CM_STAT_BUSY;
}
/*---------------------------------------------------------------------------*/
uint8_t
i2c_master_error(void)
{
uint8_t temp = REG(I2CM_STAT); /* Get all status */
if(temp & I2CM_STAT_BUSY) { /* No valid if BUSY bit is set */
return I2C_MASTER_ERR_NONE;
} else if(temp & (I2CM_STAT_ERROR | I2CM_STAT_ARBLST)) {
return temp; /* Compare later */
}
return I2C_MASTER_ERR_NONE;
}
/*---------------------------------------------------------------------------*/
uint8_t
i2c_single_send(uint8_t slave_addr, uint8_t data)
{
i2c_master_set_slave_address(slave_addr, I2C_SEND);
i2c_master_data_put(data);
i2c_master_command(I2C_MASTER_CMD_SINGLE_SEND);
while(i2c_master_busy());
/* Return the STAT register of I2C module if error occured, I2C_MASTER_ERR_NONE otherwise */
return i2c_master_error();
}
/*---------------------------------------------------------------------------*/
uint8_t
i2c_single_receive(uint8_t slave_addr, uint8_t *data)
{
uint32_t temp;
i2c_master_set_slave_address(slave_addr, I2C_RECEIVE);
i2c_master_command(I2C_MASTER_CMD_SINGLE_RECEIVE);
while(i2c_master_busy());
temp = i2c_master_error();
if(temp == I2C_MASTER_ERR_NONE) {
*data = i2c_master_data_get();
}
return temp;
}
/*---------------------------------------------------------------------------*/
uint8_t
i2c_burst_send(uint8_t slave_addr, uint8_t *data, uint8_t len)
{
uint8_t sent;
if((len == 0) || (data == NULL)) {
return I2CM_STAT_INVALID;
}
if(len == 1) {
return i2c_single_send(slave_addr, data[0]);
}
i2c_master_set_slave_address(slave_addr, I2C_SEND);
i2c_master_data_put(data[0]);
i2c_master_command(I2C_MASTER_CMD_BURST_SEND_START);
while(i2c_master_busy());
if(i2c_master_error() == I2C_MASTER_ERR_NONE) {
for(sent = 1; sent <= (len - 2); sent++) {
i2c_master_data_put(data[sent]);
i2c_master_command(I2C_MASTER_CMD_BURST_SEND_CONT);
while(i2c_master_busy());
}
/* This should be the last byte, stop sending */
i2c_master_data_put(data[len - 1]);
i2c_master_command(I2C_MASTER_CMD_BURST_SEND_FINISH);
while(i2c_master_busy());
}
/* Return the STAT register of I2C module if error occurred, I2C_MASTER_ERR_NONE otherwise */
return i2c_master_error();
}
/*---------------------------------------------------------------------------*/
uint8_t
i2c_burst_receive(uint8_t slave_addr, uint8_t *data, uint8_t len)
{
uint8_t recv = 0;
if((len == 0) || data == NULL) {
return I2CM_STAT_INVALID;
}
if(len == 1) {
return i2c_single_receive(slave_addr, &data[0]);
}
i2c_master_set_slave_address(slave_addr, I2C_RECEIVE);
i2c_master_command(I2C_MASTER_CMD_BURST_RECEIVE_START);
while(i2c_master_busy());
if(i2c_master_error() == I2C_MASTER_ERR_NONE) {
data[0] = i2c_master_data_get();
/* If we got 2 or more bytes pending to be received, keep going*/
for(recv = 1; recv <= (len - 2); recv++) {
i2c_master_command(I2C_MASTER_CMD_BURST_RECEIVE_CONT);
while(i2c_master_busy());
data[recv] = i2c_master_data_get();
}
/* This should be the last byte, stop receiving */
i2c_master_command(I2C_MASTER_CMD_BURST_RECEIVE_FINISH);
while(i2c_master_busy());
data[len - 1] = i2c_master_data_get();
}
return i2c_master_error();
}
/*---------------------------------------------------------------------------*/
/** @} */