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/*++
Module Name:
I2C.h
Abstract:
This file contains the declarations for I2C functions and callbacks.
Environment:
Kernel-mode Driver Framework
--*/
#pragma once
// Number of platform-level device resets to attempt.
#define MAX_DEVICE_RESET_ATTEMPTS 3
// Transfers required for an I2C read or write operation.
// The first transfer in the sequence writes a one-byte register address to the device.
// The second transfer reads from or writes to the selected register.
#define I2C_TRANSFER_COUNT 2
#define REGISTER_ADDR_SIZE 1
// Timeout in milliseconds for synchronous I2C reads/writes.
// The I2C specification does not specify a timeout. 300 ms was chosen arbitrarily.
#define I2C_SYNCHRONOUS_TIMEOUT 300
// Size used to initialize the I2C read and write buffers.
#define I2C_BUFFER_SIZE 50
typedef struct _DEVICE_CONTEXT DEVICE_CONTEXT, *PDEVICE_CONTEXT;
enum I2C_REQUEST_SOURCE;
typedef struct _REGISTER_ITEM
{
UINT8 RegisterAddress;
_Out_writes_bytes_(Length) PVOID Data;
ULONG Length;
} REGISTER_ITEM, *PREGISTER_ITEM;
// Helper macro to generate an array item.
#define GEN_REGISTER_ITEM(RegisterAddress, Variable) \
{ (RegisterAddress), &(Variable), sizeof((Variable)) }
#ifndef _countof
#define _countof(_Array) (sizeof(_Array) / sizeof(_Array[0]))
#endif
EXTERN_C_START
NTSTATUS
I2CInitialize(
_In_ PDEVICE_CONTEXT DeviceContext,
_In_ WDFCMRESLIST ResourcesRaw,
_In_ WDFCMRESLIST ResourcesTranslated
);
NTSTATUS
I2COpen(
_In_ PDEVICE_CONTEXT DeviceContext
);
void
I2CClose(
_In_ PDEVICE_CONTEXT DeviceContext
);
NTSTATUS
I2CWriteAsynchronously(
_In_ PDEVICE_CONTEXT DeviceContext,
_In_ UINT8 RegisterAddress,
_In_reads_bytes_(Length) PVOID Data,
_In_ ULONG Length
);
NTSTATUS
I2CReadAsynchronously(
_In_ PDEVICE_CONTEXT DeviceContext,
_In_ UINT8 RegisterAddress,
_In_ ULONG Length
);
NTSTATUS
I2CReadSynchronously(
_In_ PDEVICE_CONTEXT DeviceContext,
_In_ I2C_REQUEST_SOURCE requestSource,
_In_ UINT8 RegisterAddress,
_Out_writes_bytes_(Length) PVOID Data,
_In_ ULONG Length
);
NTSTATUS
I2CWriteSynchronously(
_In_ PDEVICE_CONTEXT DeviceContext,
_In_ I2C_REQUEST_SOURCE requestSource,
_In_ UINT8 RegisterAddress,
_In_reads_(Length) PVOID Data,
_In_ ULONG Length
);
NTSTATUS
I2CReadSynchronouslyMultiple(
_In_ PDEVICE_CONTEXT DeviceContext,
_In_ I2C_REQUEST_SOURCE requestSource,
_Inout_updates_(Count) REGISTER_ITEM* Items,
_In_ ULONG Count
);
EVT_WDF_REQUEST_COMPLETION_ROUTINE
I2COnReadCompletion;
EVT_WDF_REQUEST_COMPLETION_ROUTINE
I2COnWriteCompletion;
void
I2CPerformDeviceReset(
_In_ PDEVICE_CONTEXT DeviceContext
);
EXTERN_C_END
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