i2c_tca9548.cc

// Copyright 2023-2024 The Aerospace Corporation.
// This file is a part of SatCat5, licensed under CERN-OHL-W v2 or later.
 
#include <hal_devices/i2c_tca9548.h>
 
using satcat5::cfg::I2cGeneric;
using satcat5::cfg::I2cEventListener;
using satcat5::device::i2c::Tca9548;
using satcat5::util::I2cAddr;
using satcat5::util::modulo_add_uns;
 
Tca9548::Tca9548(I2cGeneric* i2c, const I2cAddr& devaddr)
    : m_parent(i2c)
    , m_devaddr(devaddr)
    , m_cb_count(0)
    , m_cb_rdidx(0)
{
    // Nothing else to initialize.
}
 
bool Tca9548::select_mask(u8 mask)
{
    // Issue the "select" command only if bus is idle.
    if (m_cb_count > 0) return false;
    return m_parent->write(m_devaddr, 0, 0, 1, &mask);
}
 
bool Tca9548::busy()
{
    return (m_cb_count > 0) || m_parent->busy();
}
 
bool Tca9548::read(const I2cAddr& devaddr,
    u8 regbytes, u32 regaddr, u8 nread,
    I2cEventListener* callback)
{
    // Reject command if our callback queue is full.
    if (m_cb_count >= SATCAT5_I2C_MAXCMD) return false;
 
    // Otherwise, store the pointer and call parent.
    m_cb_queue[cb_wridx()] = callback;
    bool ok = m_parent->read(devaddr, regbytes, regaddr, nread, this);
 
    // If the parent succeeds, increment the queue count.
    if (ok) ++m_cb_count;
    return ok;
}
 
bool Tca9548::write(const I2cAddr& devaddr,
    u8 regbytes, u32 regaddr, u8 nwrite, const u8* data,
    I2cEventListener* callback)
{
    // Reject command if our callback queue is full.
    if (m_cb_count >= SATCAT5_I2C_MAXCMD) return false;
 
    // Otherwise, store the pointer and call parent.
    m_cb_queue[cb_wridx()] = callback;
    bool ok = m_parent->write(devaddr, regbytes, regaddr, nwrite, data, this);
 
    // If the parent succeeds, increment the queue count.
    if (ok) ++m_cb_count;
    return ok;
}
 
void Tca9548::i2c_done(
    bool noack, const I2cAddr& devaddr,
    u32 regaddr, unsigned nread, const u8* rdata)
{
    // Pop callback off the circular buffer.
    I2cEventListener* cb = m_cb_queue[m_cb_rdidx];
    m_cb_rdidx = modulo_add_uns(m_cb_rdidx + 1, SATCAT5_I2C_MAXCMD);
    --m_cb_count;
 
    // Forward the callback event if applicable.
    if (cb) cb->i2c_done(noack, devaddr, regaddr, nread, rdata);
}