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/****************************************************************************
*
* Copyright (C) 2012 PX4 Development Team. 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 PX4 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 OWNER 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.
*
****************************************************************************/
/**
* @file i2c.c
*
* I2C communication for the PX4IO module.
*/
#include <stdint.h>
#include <nuttx/arch.h>
#include <arch/board/board.h>
#include <stm32_i2c.h>
#define DEBUG
#include "px4io.h"
/*
* I2C register definitions.
*/
#define I2C_BASE STM32_I2C1_BASE
#define REG(_reg) (*(volatile uint32_t *)(I2C_BASE + _reg))
#define rCR1 REG(STM32_I2C_CR1_OFFSET)
#define rCR2 REG(STM32_I2C_CR2_OFFSET)
#define rOAR1 REG(STM32_I2C_OAR1_OFFSET)
#define rOAR2 REG(STM32_I2C_OAR2_OFFSET)
#define rDR REG(STM32_I2C_DR_OFFSET)
#define rSR1 REG(STM32_I2C_SR1_OFFSET)
#define rSR2 REG(STM32_I2C_SR2_OFFSET)
#define rCCR REG(STM32_I2C_CCR_OFFSET)
#define rTRISE REG(STM32_I2C_TRISE_OFFSET)
static int i2c_interrupt(int irq, void *context);
static void i2c_dump(void);
void
i2c_init(void)
{
// enable the i2c block clock and reset it
modifyreg32(STM32_RCC_APB1ENR, 0, RCC_APB1ENR_I2C1EN);
modifyreg32(STM32_RCC_APB1RSTR, 0, RCC_APB1RSTR_I2C1RST);
modifyreg32(STM32_RCC_APB1RSTR, RCC_APB1RSTR_I2C1RST, 0);
// configure the i2c GPIOs
stm32_configgpio(GPIO_I2C1_SCL);
stm32_configgpio(GPIO_I2C1_SDA);
// soft-reset the block
rCR1 |= I2C_CR1_SWRST;
rCR1 = 0;
// set the frequency value in CR2
rCR2 &= ~I2C_CR2_FREQ_MASK;
rCR2 |= STM32_PCLK1_FREQUENCY / 1000000;
// set divisor and risetime for fast mode
uint16_t result = STM32_PCLK1_FREQUENCY / (400000 * 25);
if (result < 1)
result = 1;
result = 3;
rCCR &= ~I2C_CCR_CCR_MASK;
rCCR |= I2C_CCR_DUTY | I2C_CCR_FS | result;
rTRISE = (uint16_t)((((STM32_PCLK1_FREQUENCY / 1000000) * 300) / 1000) + 1);
// set our device address
rOAR1 = 0x1a << 1;
// enable event interrupts
irq_attach(STM32_IRQ_I2C1EV, i2c_interrupt);
up_enable_irq(STM32_IRQ_I2C1EV);
rCR2 |= I2C_CR2_ITEVFEN;
// and enable the I2C port
rCR1 |= I2C_CR1_ACK | I2C_CR1_PE;
i2c_dump();
}
static int
i2c_interrupt(int irq, FAR void *context)
{
uint16_t sr1 = rSR1;
// XXX not sure what else we need to do here...
if (sr1 & I2C_SR1_ERRORMASK) {
//debug("errors 0x%04x", sr1 & I2C_SR1_ERRORMASK);
//i2c_dump();
rSR1 = 0;
}
if (sr1 & I2C_SR1_ADDR) {
/* XXX we have been addressed, set up to receive */
/* clear ADDR */
(void)rSR2;
debug("addr");
}
if (sr1 & I2C_SR1_RXNE) {
debug("data 0x%02x", rDR);
}
if (sr1 & I2C_SR1_STOPF) {
/* write to CR1 to clear STOPF */
rCR1 |= I2C_CR1_PE;
debug("stop");
/* XXX handle txn */
}
return 0;
}
static void
i2c_dump(void)
{
debug("CR1 0x%08x CR2 0x%08x", rCR1, rCR2);
debug("OAR1 0x%08x OAR2 0x%08x", rOAR1, rOAR2);
debug("CCR 0x%08x TRISE 0x%08x", rCCR, rTRISE);
debug("SR1 0x%08x SR2 0x%08x", rSR1, rSR2);
}
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