File content as of revision 592:a274ee790e56:

#ifndef I2C_SLAVE_H_INCLUDED
#define I2C_SLAVE_H_INCLUDED

#include "i2c_common.h"
#include <sercom.h>
#include <pinmux.h>

#if I2C_SLAVE_CALLBACK_MODE == true
#  include <sercom_interrupt.h>
#endif

#ifndef PINMUX_DEFAULT
#  define PINMUX_DEFAULT 0
#endif

#ifdef __cplusplus
extern "C" {
#endif

/**
 * \addtogroup asfdoc_sam0_sercom_i2c_group
 *
 * @{
 *
 */

/**
 * \name I2C Slave Status Flags
 *
 * I<SUP>2</SUP>C slave status flags, returned by \ref i2c_slave_get_status() and cleared
 * by \ref i2c_slave_clear_status().
 * @{
 */

/** Address Match.
 * \note Should only be cleared internally by driver.
 */
#define I2C_SLAVE_STATUS_ADDRESS_MATCH     (1UL << 0)
/** Data Ready. */
#define I2C_SLAVE_STATUS_DATA_READY        (1UL << 1)
/** Stop Received. */
#define I2C_SLAVE_STATUS_STOP_RECEIVED     (1UL << 2)
/** Clock Hold.
 * \note Cannot be cleared, only valid when I2C_SLAVE_STATUS_ADDRESS_MATCH is
 * set.
 */
#define I2C_SLAVE_STATUS_CLOCK_HOLD        (1UL << 3)
/** SCL Low Timeout. */
#define I2C_SLAVE_STATUS_SCL_LOW_TIMEOUT   (1UL << 4)
/** Repeated Start.
 * \note Cannot be cleared, only valid when I2C_SLAVE_STATUS_ADDRESS_MATCH is
 * set.
 */
#define I2C_SLAVE_STATUS_REPEATED_START    (1UL << 5)
/** Received not acknowledge.
 * \note Cannot be cleared.
 */
#define I2C_SLAVE_STATUS_RECEIVED_NACK     (1UL << 6)
/** Transmit Collision. */
#define I2C_SLAVE_STATUS_COLLISION         (1UL << 7)
/** Bus error. */
#define I2C_SLAVE_STATUS_BUS_ERROR         (1UL << 8)

/** @} */

/**
 * \brief I<SUP>2</SUP>C slave packet for read/write
 *
 * Structure to be used when transferring I<SUP>2</SUP>C slave packets.
 */
struct i2c_slave_packet {
    /** Length of data array. */
    uint16_t data_length;
    /** Data array containing all data to be transferred. */
    uint8_t *data;
};

#if I2C_SLAVE_CALLBACK_MODE == true
/**
* \brief Callback types
*
* The available callback types for the I<SUP>2</SUP>C slave.
*/
enum i2c_slave_callback {
    /** Callback for packet write complete. */
    I2C_SLAVE_CALLBACK_WRITE_COMPLETE,
    /** Callback for packet read complete. */
    I2C_SLAVE_CALLBACK_READ_COMPLETE,
    /**
     * Callback for read request from master - can be used to
     * issue a write.
     */
    I2C_SLAVE_CALLBACK_READ_REQUEST,
    /**
     * Callback for write request from master - can be used to issue a read.
     */
    I2C_SLAVE_CALLBACK_WRITE_REQUEST,
    /** Callback for error. */
    I2C_SLAVE_CALLBACK_ERROR,
    /**
     * Callback for error in last transfer. Discovered on a new address
     * interrupt.
     */
    I2C_SLAVE_CALLBACK_ERROR_LAST_TRANSFER,
#  if !defined(__DOXYGEN__)
    /** Total number of callbacks. */
    _I2C_SLAVE_CALLBACK_N,
#  endif
};

#  if !defined(__DOXYGEN__)
/** Software module prototype. */
struct i2c_slave_module;

/** Callback type. */
typedef void (*i2c_slave_callback_t)(
    struct i2c_slave_module *const module);
#  endif
#endif

/**
 * \brief Enum for the possible SDA hold times with respect to the negative
 * edge of SCL
 *
 * Enum for the possible SDA hold times with respect to the negative edge
 * of SCL.
 */
enum i2c_slave_sda_hold_time {
    /** SDA hold time disabled. */
    I2C_SLAVE_SDA_HOLD_TIME_DISABLED =
        ((SERCOM_I2CS_CTRLA_SDAHOLD_Msk & ((0) << SERCOM_I2CS_CTRLA_SDAHOLD_Pos))),
    /** SDA hold time 50ns - 100ns. */
    I2C_SLAVE_SDA_HOLD_TIME_50NS_100NS =
        ((SERCOM_I2CS_CTRLA_SDAHOLD_Msk & ((1) << SERCOM_I2CS_CTRLA_SDAHOLD_Pos))),
    /** SDA hold time 300ns - 600ns. */
    I2C_SLAVE_SDA_HOLD_TIME_300NS_600NS =
        ((SERCOM_I2CS_CTRLA_SDAHOLD_Msk & ((2) << SERCOM_I2CS_CTRLA_SDAHOLD_Pos))),
    /** SDA hold time 400ns - 800ns. */
    I2C_SLAVE_SDA_HOLD_TIME_400NS_800NS =
        ((SERCOM_I2CS_CTRLA_SDAHOLD_Msk & ((3) << SERCOM_I2CS_CTRLA_SDAHOLD_Pos))),
};

/**
 * \brief Enum for the possible address modes
 *
 * Enum for the possible address modes.
 */
enum i2c_slave_address_mode {
    /** Address match on address_mask used as a mask to address. */
    I2C_SLAVE_ADDRESS_MODE_MASK = SERCOM_I2CS_CTRLB_AMODE(0),
    /** Address math on both address and address_mask. */
    I2C_SLAVE_ADDRESS_MODE_TWO_ADDRESSES = SERCOM_I2CS_CTRLB_AMODE(1),
    /**
     * Address match on range of addresses between and including address and
     * address_mask.
     */
    I2C_SLAVE_ADDRESS_MODE_RANGE = SERCOM_I2CS_CTRLB_AMODE(2),
};

/**
 * \brief Enum for the direction of a request
 *
 * Enum for the direction of a request.
 */
enum i2c_slave_direction {
    /** Read. */
    I2C_SLAVE_DIRECTION_READ,
    /** Write. */
    I2C_SLAVE_DIRECTION_WRITE,
    /** No direction. */
    I2C_SLAVE_DIRECTION_NONE,
};

#ifdef FEATURE_I2C_FAST_MODE_PLUS_AND_HIGH_SPEED
/**
 * \brief Enum for the transfer speed
 *
 * Enum for the transfer speed.
 */
enum i2c_slave_transfer_speed {
    /** Standard-mode (Sm) up to 100KHz and Fast-mode (Fm) up to 400KHz. */
    I2C_SLAVE_SPEED_STANDARD_AND_FAST = SERCOM_I2CS_CTRLA_SPEED(0),
    /** Fast-mode Plus (Fm+) up to 1MHz. */
    I2C_SLAVE_SPEED_FAST_MODE_PLUS = SERCOM_I2CS_CTRLA_SPEED(1),
    /** High-speed mode (Hs-mode) up to 3.4MHz. */
    I2C_SLAVE_SPEED_HIGH_SPEED = SERCOM_I2CS_CTRLA_SPEED(2),
};
#endif

/**
 * \brief SERCOM I<SUP>2</SUP>C Slave driver software device instance structure.
 *
 * SERCOM I<SUP>2</SUP>C Slave driver software instance structure, used to
 * retain software state information of an associated hardware module instance.
 *
 * \note The fields of this structure should not be altered by the user
 *       application; they are reserved for module-internal use only.
 */
struct i2c_slave_module {
#if !defined(__DOXYGEN__)
    /** Hardware instance initialized for the struct. */
    Sercom *hw;
    /** Module lock. */
    volatile bool locked;
    /** Timeout value for polled functions. */
    uint16_t buffer_timeout;
#  ifdef FEATURE_I2C_10_BIT_ADDRESS
    /** Using 10-bit addressing for the slave. */
    bool ten_bit_address;
#  endif
#  if I2C_SLAVE_CALLBACK_MODE == true
    /** Nack on address match. */
    bool nack_on_address;
    /** Pointers to callback functions. */
    volatile i2c_slave_callback_t callbacks[_I2C_SLAVE_CALLBACK_N];
    /** Mask for registered callbacks. */
    volatile uint8_t registered_callback;
    /** Mask for enabled callbacks. */
    volatile uint8_t enabled_callback;
    /** The total number of bytes to transfer. */
    volatile uint16_t buffer_length;
    /**
     * Counter used for bytes left to send in write and to count number of
     * obtained bytes in read.
     */
    uint16_t buffer_remaining;
    /** Data buffer for packet write and read. */
    volatile uint8_t *buffer;
    /** Save direction of request from master. 1 = read, 0 = write. */
    volatile enum i2c_transfer_direction transfer_direction;
    /** Status for status read back in error callback. */
    volatile enum status_code status;
#  endif
#endif
};

/**
 * \brief Configuration structure for the I<SUP>2</SUP>C Slave device
 *
 * This is the configuration structure for the I<SUP>2</SUP>C Slave device. It is used
 * as an argument for \ref i2c_slave_init to provide the desired
 * configurations for the module. The structure should be initialized using the
 * \ref i2c_slave_get_config_defaults.
 */
struct i2c_slave_config {
    /** Set to enable the SCL low timeout. */
    bool enable_scl_low_timeout;
    /** SDA hold time with respect to the negative edge of SCL. */
    enum i2c_slave_sda_hold_time sda_hold_time;
    /** Timeout to wait for master in polled functions. */
    uint16_t buffer_timeout;
    /** Addressing mode. */
    enum i2c_slave_address_mode address_mode;
    /** Address or upper limit of address range. */
    uint16_t address;
    /** Address mask, second address or lower limit of address range. */
    uint16_t address_mask;
#ifdef FEATURE_I2C_10_BIT_ADDRESS
    /** Enable 10-bit addressing. */
    bool ten_bit_address;
#endif
    /**
     * Enable general call address recognition (general call address
     * is defined as 0000000 with direction bit 0).
     */
    bool enable_general_call_address;

#ifdef FEATURE_I2C_FAST_MODE_PLUS_AND_HIGH_SPEED
    /** Transfer speed mode. */
    enum i2c_slave_transfer_speed transfer_speed;
#endif

#if I2C_SLAVE_CALLBACK_MODE == true
    /**
     * Enable NACK on address match (this can be changed after initialization
     * via the \ref i2c_slave_enable_nack_on_address and
     * \ref i2c_slave_disable_nack_on_address functions).
     */
    bool enable_nack_on_address;
#endif
    /** GCLK generator to use as clock source. */
    enum gclk_generator generator_source;
    /** Set to keep module active in sleep modes. */
    bool run_in_standby;
    /** PAD0 (SDA) pinmux. */
    uint32_t pinmux_pad0;
    /** PAD1 (SCL) pinmux. */
    uint32_t pinmux_pad1;
    /** Set to enable SCL low time-out. */
    bool scl_low_timeout;
#ifdef FEATURE_I2C_SCL_STRETCH_MODE
    /** Set to enable SCL stretch only after ACK bit (required for high speed). */
    bool scl_stretch_only_after_ack_bit;
#endif
#ifdef FEATURE_I2C_SCL_EXTEND_TIMEOUT
    /** Set to enable slave SCL low extend time-out. */
    bool slave_scl_low_extend_timeout;
#endif
};


/**
 * \name Lock/Unlock
 * @{
 */

/**
 * \brief Attempt to get lock on driver instance
 *
 * This function checks the instance's lock, which indicates whether or not it
 * is currently in use, and sets the lock if it was not already set.
 *
 * The purpose of this is to enable exclusive access to driver instances, so
 * that, e.g., transactions by different services will not interfere with each
 * other.
 *
 * \param[in,out] module Pointer to the driver instance to lock
 *
 * \retval STATUS_OK If the module was locked
 * \retval STATUS_BUSY If the module was already locked
 */
static inline enum status_code i2c_slave_lock(
    struct i2c_slave_module *const module)
{
    enum status_code status;

    system_interrupt_enter_critical_section();

    if (module->locked) {
        status = STATUS_BUSY;
    } else {
        module->locked = true;
        status = STATUS_OK;
    }

    system_interrupt_leave_critical_section();

    return status;
}

/**
 * \brief Unlock driver instance
 *
 * This function clears the instance lock, indicating that it is available for
 * use.
 *
 * \param[in,out] module Pointer to the driver instance to lock
 *
 * \retval STATUS_OK If the module was locked
 * \retval STATUS_BUSY If the module was already locked
 */
static inline void i2c_slave_unlock(struct i2c_slave_module *const module)
{
    module->locked = false;
}

/** @} */

/**
 * \name Configuration and Initialization
 * @{
 */

/**
 * \brief Returns the synchronization status of the module
 *
 * Returns the synchronization status of the module.
 *
 * \param[out] module  Pointer to software module structure
 *
 * \return Status of the synchronization.
 * \retval true   Module is busy synchronizing
 * \retval false  Module is not synchronizing
 */
static inline bool i2c_slave_is_syncing(
    const struct i2c_slave_module *const module)
{
    /* Sanity check */
    Assert(module);
    Assert(module->hw);

    SercomI2cs *const i2c_hw = &(module->hw->I2CS);

    /* Return sync status */
#if defined(FEATURE_SERCOM_SYNCBUSY_SCHEME_VERSION_1)
    return (i2c_hw->STATUS.reg & SERCOM_I2CS_STATUS_SYNCBUSY);
#elif defined(FEATURE_SERCOM_SYNCBUSY_SCHEME_VERSION_2)
    return (i2c_hw->SYNCBUSY.reg & SERCOM_I2CS_SYNCBUSY_MASK);
#else
#  error Unknown SERCOM SYNCBUSY scheme!
#endif
}

#if !defined(__DOXYGEN__)
/**
 * \internal Wait for hardware module to sync
 *
 * \param[in]  module  Pointer to software module structure
 */
static void _i2c_slave_wait_for_sync(
    const struct i2c_slave_module *const module)
{
    /* Sanity check. */
    Assert(module);

    while (i2c_slave_is_syncing(module)) {
        /* Wait for I2C module to sync */
    }
}
#endif

/**
 * \brief Gets the I<SUP>2</SUP>C slave default configurations
 *
 * This will initialize the configuration structure to known default values.
 *
 * The default configuration is as follows:
 * - Disable SCL low timeout
 * - 300ns - 600ns SDA hold time
 * - Buffer timeout = 65535
 * - Address with mask
 * - Address = 0
 * - Address mask = 0 (one single address)
 * - General call address disabled
 * - Address nack disabled if the interrupt driver is used
 * - GCLK generator 0
 * - Do not run in standby
 * - PINMUX_DEFAULT for SERCOM pads
 *
 * Those default configuration only availale if the device supports it:
 * - Not using 10-bit addressing
 * - Standard-mode and Fast-mode transfer speed
 * - SCL stretch disabled
 * - slave SCL low extend time-out disabled
 *
 * \param[out] config  Pointer to configuration structure to be initialized
 */
static inline void i2c_slave_get_config_defaults(
    struct i2c_slave_config *const config)
{
    /*Sanity check argument. */
    Assert(config);
    config->enable_scl_low_timeout = false;
    config->sda_hold_time = I2C_SLAVE_SDA_HOLD_TIME_300NS_600NS;
    config->buffer_timeout = 65535;
    config->address_mode = I2C_SLAVE_ADDRESS_MODE_MASK;
    config->address = 0;
    config->address_mask = 0;
#ifdef FEATURE_I2C_10_BIT_ADDRESS
    config->ten_bit_address = false;
#endif
    config->enable_general_call_address = false;
#ifdef FEATURE_I2C_FAST_MODE_PLUS_AND_HIGH_SPEED
    config->transfer_speed = I2C_SLAVE_SPEED_STANDARD_AND_FAST;
#endif
#if I2C_SLAVE_CALLBACK_MODE == true
    config->enable_nack_on_address = false;
#endif
    config->generator_source = GCLK_GENERATOR_0;
    config->run_in_standby = false;
    config->pinmux_pad0 = PINMUX_DEFAULT;
    config->pinmux_pad1 = PINMUX_DEFAULT;
    config->scl_low_timeout  = false;
#ifdef FEATURE_I2C_SCL_STRETCH_MODE
    config->scl_stretch_only_after_ack_bit = false;
#endif
#ifdef FEATURE_I2C_SCL_EXTEND_TIMEOUT
    config->slave_scl_low_extend_timeout   = false;
#endif
}

enum status_code i2c_slave_init(struct i2c_slave_module *const module,
                                Sercom *const hw,
                                const struct i2c_slave_config *const config);

/**
 * \brief Enables the I<SUP>2</SUP>C module
 *
 * This will enable the requested I<SUP>2</SUP>C module.
 *
 * \param[in]  module Pointer to the software module struct
 */
static inline void i2c_slave_enable(
    const struct i2c_slave_module *const module)
{
    /* Sanity check of arguments. */
    Assert(module);
    Assert(module->hw);

    SercomI2cs *const i2c_hw = &(module->hw->I2CS);

#if I2C_SLAVE_CALLBACK_MODE == true
    /* Enable global interrupt for module */
    system_interrupt_enable(_sercom_get_interrupt_vector(module->hw));
#endif

    /* Wait for module to sync */
    _i2c_slave_wait_for_sync(module);

    /* Enable module */
    i2c_hw->CTRLA.reg |= SERCOM_I2CS_CTRLA_ENABLE;
}


/**
 * \brief Disables the I<SUP>2</SUP>C module
 *
 * This will disable the I<SUP>2</SUP>C module specified in the provided software module
 * structure.
 *
 * \param[in]  module  Pointer to the software module struct
 */
static inline void i2c_slave_disable(
    const struct i2c_slave_module *const module)
{
    /* Sanity check of arguments. */
    Assert(module);
    Assert(module->hw);

    SercomI2cs *const i2c_hw = &(module->hw->I2CS);

#if I2C_SLAVE_CALLBACK_MODE == true
    /* Disable interrupts */
    i2c_hw->INTENCLR.reg = SERCOM_I2CS_INTENSET_PREC |
                           SERCOM_I2CS_INTENSET_AMATCH | SERCOM_I2CS_INTENSET_DRDY;

    /* Clear interrupt flags */
    i2c_hw->INTFLAG.reg = SERCOM_I2CS_INTFLAG_PREC | SERCOM_I2CS_INTFLAG_AMATCH |
                          SERCOM_I2CS_INTFLAG_DRDY;

    /* Disable global interrupt for module */
    system_interrupt_disable(_sercom_get_interrupt_vector(module->hw));
#endif

    /* Wait for module to sync */
    _i2c_slave_wait_for_sync(module);

    /* Disable module */
    i2c_hw->CTRLA.reg &= ~SERCOM_I2CS_CTRLA_ENABLE;
}

void i2c_slave_reset(
    struct i2c_slave_module *const module);

/** @} */

/**
 * \name Read and Write
 * @{
 */

enum status_code i2c_slave_write_packet_wait(
    struct i2c_slave_module *const module,
    struct i2c_slave_packet *const packet);
enum status_code i2c_slave_read_packet_wait(
    struct i2c_slave_module *const module,
    struct i2c_slave_packet *const packet);
enum i2c_slave_direction i2c_slave_get_direction_wait(
    struct i2c_slave_module *const module);

/** @} */

/**
 * \name Status Management
 * @{
 */
uint32_t i2c_slave_get_status(
    struct i2c_slave_module *const module);
void i2c_slave_clear_status(
    struct i2c_slave_module *const module,
    uint32_t status_flags);
/** @} */

#ifdef FEATURE_I2C_DMA_SUPPORT
/**
 * \name SERCOM I2C Slave with DMA Interfaces
 * @{
 */

/**
 * \brief Read SERCOM I<SUP>2</SUP>C interrupt status.
 *
 * Read I<SUP>2</SUP>C interrupt status for DMA transfer.
 *
 * \param[in,out] module Pointer to the driver instance to lock
 *
 */
static inline uint8_t i2c_slave_dma_read_interrupt_status(struct i2c_slave_module *const module)
{
    return (uint8_t)module->hw->I2CS.INTFLAG.reg;
}

/**
 * \brief Write SERCOM I<SUP>2</SUP>C interrupt status.
 *
 * Write I<SUP>2</SUP>C interrupt status for DMA transfer.
 *
 * \param[in,out] module Pointer to the driver instance to lock
 * \param[in] flag Interrupt flag status
 *
 */
static inline void i2c_slave_dma_write_interrupt_status(struct i2c_slave_module *const module,
        uint8_t flag)
{
    module->hw->I2CS.INTFLAG.reg = flag;
}

/** @} */
#endif

/** @} */

#ifdef __cplusplus
}
#endif

#endif /* I2C_SLAVE_H_INCLUDED */