STMicroelectronics' implementation of an I2S driver, also including DMA support.

Dependents:   temp X_NUCLEO_CCA01M1 X_NUCLEO_CCA01M1 X_NUCLEO_CCA02M1

Platform compatibility

This driver has been designed to support a wide range of the Nucleo F4 Family of platforms and MCUs, but not all members of this family support I2S and/or some of the members might require slight modifications to the sources of this driver in order to make it work on those.

This driver has for now been tested only with the following platforms:

drivers/I2S.cpp

Committer:
Wolfgang Betz
Date:
2017-07-12
Revision:
31:bb4bac0874da
Parent:
25:bc19a42307ae

File content as of revision 31:bb4bac0874da:

#include "drivers/I2S.h"
#include "platform/mbed_critical.h"
#include "platform/mbed_assert.h"

#if DEVICE_I2S

I2S* I2S::_owner = NULL;
SingletonPtr<PlatformMutex> I2S::_mutex; // intentional class level lock!

events::EventQueue I2S::i2s_bh_queue;

void I2S::lock() {
#if defined(NDEBUG) || !defined(MBED_CONF_RTOS_PRESENT)
    _mutex->lock(); // intentional class level lock!
#else
    osStatus ret = _mutex->lock(); // intentional class level lock!
    MBED_ASSERT(ret == osOK);
#endif
}

void I2S::unlock() {
#if defined(NDEBUG) || !defined(MBED_CONF_RTOS_PRESENT)
    _mutex->unlock(); // intentional class level lock!
#else
    osStatus ret = _mutex->unlock(); // intentional class level lock!
    MBED_ASSERT(ret == osOK);
#endif
}

I2S::I2S(PinName dpin, PinName clk, PinName wsel, PinName fdpin, PinName mck) :
    _i2s(),
    _irq_tx(this), _irq_rx(this),
    _priority(MEDIUM),
    _dbits(16),
    _fbits(16),
    _polarity(0),
    _protocol(PHILIPS),
    _mode(MASTER_TX),
    _circular(false),
    _hz(44100) {
    lock();
    /* Init instance */
    i2s_init(&_i2s, dpin, clk, wsel, fdpin, mck, _mode);
    acquire();
    unlock();
}

int I2S::format(int dbits, int fbits, int polarity) {
    lock();
    if (i2s_active(&_i2s)) {
	unlock();
	return -1;
    }
    _dbits = dbits;
    _fbits = fbits;
    _polarity = polarity;
    I2S::_owner = NULL; // Not that elegant, but works. rmeyer
    acquire();
    unlock();
    return 0;
}

int I2S::audio_frequency(unsigned int hz) {
    lock();
    if (i2s_active(&_i2s)) {
	unlock();
	return -1;
    }
    _hz = hz;
    I2S::_owner = NULL; // Not that elegant, but works. rmeyer
    acquire();
    unlock();
    return 0;
}

int I2S::protocol(i2s_bitorder_t protocol) {
    lock();
    if (i2s_active(&_i2s)) {
	unlock();
	return -1;
    }
    _protocol = protocol;
    I2S::_owner = NULL; // Not that elegant, but works. rmeyer
    acquire();
    unlock();
    return 0;
}

int I2S::mode(i2s_mode_t mode, bool circular) {
    lock();
    if (i2s_active(&_i2s)) {
	unlock();
	return -1;
    }
    _mode = mode;
    _circular = circular;
    I2S::_owner = NULL; // Not that elegant, but works. rmeyer
    acquire();
    unlock();
    return 0;
}

int I2S::harmonize(I2S &dev_i2s_1, I2S &dev_i2s_2) {
    dev_i2s_1.lock();
    if (i2s_active(&dev_i2s_1._i2s)) {
	dev_i2s_1.unlock();
	return -1;
    }

    dev_i2s_2.lock();
    if (i2s_active(&dev_i2s_2._i2s)) {
	dev_i2s_2.unlock();
	dev_i2s_1.unlock();
	return -1;
    }

    uint32_t hz1 = dev_i2s_1._hz;
    uint32_t hz2 = dev_i2s_2._hz;
    int8_t ret = i2s_harmonize(&dev_i2s_1._i2s, &hz1, &dev_i2s_2._i2s, &hz2);

    if(ret == 0) {
	dev_i2s_1.audio_frequency(hz1);
	dev_i2s_2.audio_frequency(hz2);
    }

    dev_i2s_2.unlock();
    dev_i2s_1.unlock();

    return ret;
}

void I2S::abort_transfer()
{
    lock();
    i2s_abort_asynch(&_i2s);
#if TRANSACTION_QUEUE_SIZE_I2S
    dequeue_transaction();
#endif
    unlock();
}


void I2S::clear_transfer_buffer()
{
#if TRANSACTION_QUEUE_SIZE_I2S
    lock();
    _transaction_buffer.reset();
    unlock();
#endif
}

void I2S::abort_all_transfers()
{
    lock();
    clear_transfer_buffer();
    abort_transfer();
    unlock();
}

int I2S::get_transfer_status()
{
    lock();
    if (i2s_active(&_i2s)) {
	unlock();
	return -1;
    }
    unlock();
    return  0;
}

unsigned int I2S::get_module()
{
    return i2s_get_module(&_i2s);
}

int I2S::dma_priority(i2s_dma_prio_t prio)
{
    lock();
    if (i2s_active(&_i2s)) {
	unlock();
	return -1;
    }
    _priority = prio;
    unlock();
    return  0;
}

int I2S::queue_transfer(const void *tx_buffer, int tx_length, void *rx_buffer, int rx_length, const mbed::event_callback_t& callback, int event)
{ // NOTE: MUST be called with lock held!
#if TRANSACTION_QUEUE_SIZE_I2S
    mbed::transaction_t t;

    t.tx_buffer = const_cast<void *>(tx_buffer);
    t.tx_length = tx_length;
    t.rx_buffer = rx_buffer;
    t.rx_length = rx_length;
    t.event = event;
    t.callback = callback;
    t.width = 16;
    mbed::Transaction<I2S> transaction(this, t);
    core_util_critical_section_enter();
    if (_transaction_buffer.full()) {
	core_util_critical_section_enter();
	return -1; // the buffer is full
    } else {
	_transaction_buffer.push(transaction);
	core_util_critical_section_exit();
	return 0;
    }
#else
    return -1;
#endif
}


// ignore the fact that there are multiple physical i2s's, and always update if it wasn't us last
void I2S::acquire() { // NOTE: MUST be called with lock held!
    if (_owner != this) {
	i2s_format(&_i2s, _dbits, _fbits, _polarity);
	i2s_audio_frequency(&_i2s, _hz);
	i2s_set_protocol(&_i2s, _protocol);
	i2s_set_mode(&_i2s, _mode);
	_owner = this;
    }
}

void I2S::start_transfer(const void *tx_buffer, int tx_length, void *rx_buffer, int rx_length, 
			 const mbed::event_callback_t& callback, int event)
{ // NOTE: MUST be called with lock held!
    acquire();
    _callback = callback;
    _irq_tx.callback(&I2S::irq_handler_asynch_tx);
    _irq_rx.callback(&I2S::irq_handler_asynch_rx);
    i2s_transfer(&_i2s,
		 const_cast<void *>(tx_buffer), tx_length, rx_buffer, rx_length,
		 _circular, _priority,
		 _irq_tx.entry(), _irq_rx.entry(),
		 event);
}

#if TRANSACTION_QUEUE_SIZE_I2S

void I2S::start_transaction(mbed::transaction_t *data)
{ // NOTE: MUST be called with lock held!
    start_transfer(data->tx_buffer, data->tx_length, data->rx_buffer, data->rx_length, data->callback, data->event);
}

void I2S::dequeue_transaction()
{
    lock();
    if (!i2s_active(&_i2s)) {
	mbed::Transaction<I2S> t;
	if (_transaction_buffer.pop(t)) {
	    I2S* obj = t.get_object();
	    mbed::transaction_t* data = t.get_transaction();
	    MBED_ASSERT(obj == this);
	    obj->start_transaction(data);
	}
    }
    unlock();
}

#endif

void I2S::irq_handler_asynch_rx(void)
{
    int event = i2s_irq_handler_asynch(&_i2s, I2S_RX_EVENT);
    if (_callback && (event & I2S_EVENT_ALL)) {
	I2sBhHandler::i2s_defer_function(_callback, event & I2S_EVENT_ALL);
    }
#if TRANSACTION_QUEUE_SIZE_I2S
    if (event & I2S_EVENT_INTERNAL_TRANSFER_COMPLETE) {
	I2sBhHandler::i2s_defer_function(mbed::Callback<void()>(this, &I2S::dequeue_transaction));
    }
#endif
}

void I2S::irq_handler_asynch_tx(void)
{
    int event = i2s_irq_handler_asynch(&_i2s, I2S_TX_EVENT);
    if (_callback && (event & I2S_EVENT_ALL)) {
	I2sBhHandler::i2s_defer_function(_callback, event & I2S_EVENT_ALL);
    }
#if TRANSACTION_QUEUE_SIZE_I2S
    if (event & I2S_EVENT_INTERNAL_TRANSFER_COMPLETE) {
	I2sBhHandler::i2s_defer_function(mbed::Callback<void()>(this, &I2S::dequeue_transaction));
    }
#endif
}

#endif // DEVICE_I2S