LPI2C_EDMA: EDMA based LPI2C Driver

Read Guidance

The LPI2C_EDMA module provide a method for LPI2C transfer operation based on EDMA.

Data Structures
struct	lpi2c_master_edma_transfer_handle_t
	Driver handle for master DMA APIs. More...

Typedefs
typedef void(*	lpi2c_master_edma_transfer_callback_t )(lpi2c_master_edma_transfer_handle_t *psHandle)
	Master DMA completion callback function pointer type. More...

Master DMA
void	LPI2C_MasterCreateEDMAHandle (LPI2C_Type *base, lpi2c_master_edma_transfer_handle_t *psHandle, lpi2c_master_edma_transfer_callback_t pfcallback, void *pUserData, DMA_Type *edmaBase, edma_channel_t eEdmaTxChannel, edma_channel_t eEdmaRxChannel)
	Create a new handle for the LPI2C master DMA APIs. More...
status_t	LPI2C_MasterTransferEDMA (lpi2c_master_edma_transfer_handle_t *psHandle, lpi2c_master_transfer_t *psTransfer)
	Performs a non-blocking DMA-based transaction on the I2C bus. More...
status_t	LPI2C_MasterTransferGetCountEDMA (lpi2c_master_edma_transfer_handle_t *psHandle, uint16_t *pu16Count)
	Returns number of bytes transferred so far. More...
status_t	LPI2C_MasterTransferAbortEDMA (lpi2c_master_edma_transfer_handle_t *psHandle)
	Terminates a non-blocking LPI2C master transmission early. More...

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Data Structure Documentation

struct _lpi2c_master_edma_transfer_handle

Note

The contents of this structure are private and subject to change.

Data Fields
LPI2C_Type *	base
	LPI2C base pointer. More...
bool	bIsBusy
	Transfer state machine current state. More...
uint8_t	u8Nbytes
	eDMA minor byte transfer count initially configured. More...
uint16_t	u16CommandBuffer [7]
	LPI2C command sequence. More...
lpi2c_master_transfer_t	sTransfer
	Copy of the current transfer info. More...
lpi2c_master_edma_transfer_callback_t	pfCallback
	Callback function pointer. More...
status_t	completionStatus
	Either #kStatus_Success or an error code describing how the transfer completed. More...
void *	pUserData
	Application data passed to callback. More...
edma_handle_t	sRxDmaHandle
	Handle for receive DMA channel. More...
edma_handle_t	sTxDmaHandle
	Handle for transmit DMA channel. More...

Field Documentation

LPI2C_Type* lpi2c_master_edma_transfer_handle_t::base

bool lpi2c_master_edma_transfer_handle_t::bIsBusy

uint8_t lpi2c_master_edma_transfer_handle_t::u8Nbytes

uint16_t lpi2c_master_edma_transfer_handle_t::u16CommandBuffer[7]

lpi2c_master_transfer_t lpi2c_master_edma_transfer_handle_t::sTransfer

lpi2c_master_edma_transfer_callback_t lpi2c_master_edma_transfer_handle_t::pfCallback

status_t lpi2c_master_edma_transfer_handle_t::completionStatus

void* lpi2c_master_edma_transfer_handle_t::pUserData

edma_handle_t lpi2c_master_edma_transfer_handle_t::sRxDmaHandle

edma_handle_t lpi2c_master_edma_transfer_handle_t::sTxDmaHandle

Typedef Documentation

typedef void(* lpi2c_master_edma_transfer_callback_t)(lpi2c_master_edma_transfer_handle_t *psHandle)

This callback is used only for the non-blocking master transfer API. Specify the callback you wish to use in the call to LPI2C_MasterCreateEDMAHandle().

Parameters

psHandle

Handle associated with the completed transfer.

Function Documentation

void LPI2C_MasterCreateEDMAHandle	(	LPI2C_Type *	base,
		lpi2c_master_edma_transfer_handle_t *	psHandle,
		lpi2c_master_edma_transfer_callback_t	pfcallback,
		void *	pUserData,
		DMA_Type *	edmaBase,
		edma_channel_t	eEdmaTxChannel,
		edma_channel_t	eEdmaRxChannel
	)

The creation of a handle is for use with the DMA APIs. Once a handle is created, there is not a corresponding destroy handle. If the user wants to terminate a transfer, the LPI2C_MasterTransferAbortEDMA() API shall be called.

For devices where the LPI2C send and receive DMA requests are OR'd together, the txDmaHandle parameter is ignored and may be set to NULL.

Parameters

base	The LPI2C peripheral base address.
psHandle	Pointer to the LPI2C master driver handle.
pfcallback	User provided pointer to the asynchronous callback function.
pUserData	User provided pointer to the application callback data.
edmaBase	Edma base address.
eEdmaTxChannel	eDMA channel for master transfer Tx request.
eEdmaTxChannel	eDMA channel for master transfer Rx request.

status_t LPI2C_MasterTransferEDMA	(	lpi2c_master_edma_transfer_handle_t *	psHandle,
		lpi2c_master_transfer_t *	psTransfer
	)

The callback specified when the handle was created is invoked when the transaction has completed.

Parameters

psHandle	Pointer to the LPI2C master driver handle.
psTransfer	The pointer to the transfer descriptor.

Return values

#kStatus_Success	The transaction was started successfully.
kStatus_LPI2C_Busy	Either another master is currently utilizing the bus, or another DMA transaction is already in progress.

status_t LPI2C_MasterTransferGetCountEDMA	(	lpi2c_master_edma_transfer_handle_t *	psHandle,
		uint16_t *	pu16Count
	)

Parameters

psHandle	Pointer to the LPI2C master driver handle.
pu16Count	Number of bytes transferred so far by the non-blocking transaction.

Return values

#kStatus_Success
#kStatus_NoTransferInProgress	There is not a DMA transaction currently in progress.

status_t LPI2C_MasterTransferAbortEDMA

(

lpi2c_master_edma_transfer_handle_t *

psHandle

)

Note

It is not safe to call this function from an IRQ handler that has a higher priority than the eDMA peripheral's IRQ priority.

Parameters

psHandle

Pointer to the LPI2C master driver handle.

Return values

#kStatus_Success	A transaction was successfully aborted.
kStatus_LPI2C_Idle	There is not a DMA transaction currently in progress.