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//
// Copyright 2011-2012,2014 Ettus Research LLC
// Copyright 2018 Ettus Research, a National Instruments Company
//
// SPDX-License-Identifier: GPL-3.0-or-later
//
#include <uhd/exception.hpp>
#include <uhd/utils/log.hpp>
#include <uhdlib/usrp/cores/i2c_core_200.hpp>
#include <chrono>
#include <mutex>
#include <thread>
#define REG_I2C_WR_PRESCALER_LO (1 << 3) | 0
#define REG_I2C_WR_PRESCALER_HI (1 << 3) | 1
#define REG_I2C_WR_CTRL (1 << 3) | 2
#define REG_I2C_WR_DATA (1 << 3) | 3
#define REG_I2C_WR_CMD (1 << 3) | 4
#define REG_I2C_RD_DATA (0 << 3) | 3
#define REG_I2C_RD_ST (0 << 3) | 4
//
// STA, STO, RD, WR, and IACK bits are cleared automatically
//
#define I2C_CTRL_EN (1 << 7) // core enable
#define I2C_CTRL_IE (1 << 6) // interrupt enable
#define I2C_CMD_START (1 << 7) // generate (repeated) start condition
#define I2C_CMD_STOP (1 << 6) // generate stop condition
#define I2C_CMD_RD (1 << 5) // read from slave
#define I2C_CMD_WR (1 << 4) // write to slave
#define I2C_CMD_NACK (1 << 3) // when a rcvr, send ACK (ACK=0) or NACK (ACK=1)
#define I2C_CMD_RSVD_2 (1 << 2) // reserved
#define I2C_CMD_RSVD_1 (1 << 1) // reserved
#define I2C_CMD_IACK (1 << 0) // set to clear pending interrupt
#define I2C_ST_RXACK (1 << 7) // Received acknowledgement from slave (1 = NAK, 0 = ACK)
#define I2C_ST_BUSY \
(1 << 6) // 1 after START signal detected; 0 after STOP signal detected
#define I2C_ST_AL (1 << 5) // Arbitration lost. 1 when core lost arbitration
#define I2C_ST_RSVD_4 (1 << 4) // reserved
#define I2C_ST_RSVD_3 (1 << 3) // reserved
#define I2C_ST_RSVD_2 (1 << 2) // reserved
#define I2C_ST_TIP (1 << 1) // Transfer-in-progress
#define I2C_ST_IP (1 << 0) // Interrupt pending
using namespace uhd;
i2c_core_200::~i2c_core_200(void)
{
/* NOP */
}
class i2c_core_200_impl : public i2c_core_200
{
public:
i2c_core_200_impl(wb_iface::sptr iface, const size_t base, const size_t readback)
: _iface(iface), _base(base), _readback(readback)
{
// init I2C FPGA interface.
this->poke(REG_I2C_WR_CTRL, 0x0000);
// set prescalers to operate at 400kHz: WB_CLK is 64MHz...
static const uint32_t i2c_datarate = 400000;
static const uint32_t wishbone_clk = 64000000; // FIXME should go somewhere else
uint16_t prescaler = wishbone_clk / (i2c_datarate * 5) - 1;
this->poke(REG_I2C_WR_PRESCALER_LO, prescaler & 0xFF);
this->poke(REG_I2C_WR_PRESCALER_HI, (prescaler >> 8) & 0xFF);
this->poke(REG_I2C_WR_CTRL, I2C_CTRL_EN); // enable I2C core
}
void write_i2c(uint16_t addr, const byte_vector_t& bytes) override
{
this->poke(REG_I2C_WR_DATA, (addr << 1) | 0); // addr and read bit (0)
this->poke(REG_I2C_WR_CMD,
I2C_CMD_WR | I2C_CMD_START | (bytes.empty() ? I2C_CMD_STOP : 0));
// wait for previous transfer to complete
if (not wait_chk_ack()) {
this->poke(REG_I2C_WR_CMD, I2C_CMD_STOP);
return;
}
for (size_t i = 0; i < bytes.size(); i++) {
this->poke(REG_I2C_WR_DATA, bytes[i]);
this->poke(REG_I2C_WR_CMD,
I2C_CMD_WR | ((i == (bytes.size() - 1)) ? I2C_CMD_STOP : 0));
if (!wait_chk_ack()) {
this->poke(REG_I2C_WR_CMD, I2C_CMD_STOP);
return;
}
}
}
byte_vector_t read_i2c(uint16_t addr, size_t num_bytes) override
{
byte_vector_t bytes;
if (num_bytes == 0)
return bytes;
while (this->peek(REG_I2C_RD_ST) & I2C_ST_BUSY) {
/* NOP */
}
this->poke(REG_I2C_WR_DATA, (addr << 1) | 1); // addr and read bit (1)
this->poke(REG_I2C_WR_CMD, I2C_CMD_WR | I2C_CMD_START);
// wait for previous transfer to complete
if (not wait_chk_ack()) {
this->poke(REG_I2C_WR_CMD, I2C_CMD_STOP);
}
for (size_t i = 0; i < num_bytes; i++) {
this->poke(REG_I2C_WR_CMD,
I2C_CMD_RD | ((num_bytes == i + 1) ? (I2C_CMD_STOP | I2C_CMD_NACK) : 0));
i2c_wait();
bytes.push_back(this->peek(REG_I2C_RD_DATA));
}
return bytes;
}
private:
void i2c_wait(void)
{
for (size_t i = 0; i < 100; i++) {
if ((this->peek(REG_I2C_RD_ST) & I2C_ST_TIP) == 0)
return;
std::this_thread::sleep_for(std::chrono::milliseconds(1));
}
UHD_LOGGER_ERROR("CORES") << "i2c_core_200: i2c_wait timeout";
}
bool wait_chk_ack(void)
{
i2c_wait();
return (this->peek(REG_I2C_RD_ST) & I2C_ST_RXACK) == 0;
}
void poke(const size_t what, const uint8_t cmd)
{
std::lock_guard<std::mutex> lock(_mutex);
_iface->poke32(_base, (what << 8) | cmd);
}
uint8_t peek(const size_t what)
{
std::lock_guard<std::mutex> lock(_mutex);
_iface->poke32(_base, what << 8);
return uint8_t(_iface->peek32(_readback));
}
wb_iface::sptr _iface;
const size_t _base;
const size_t _readback;
std::mutex _mutex;
};
i2c_core_200::sptr i2c_core_200::make(
wb_iface::sptr iface, const size_t base, const size_t readback)
{
return sptr(new i2c_core_200_impl(iface, base, readback));
}
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