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/** @file
I2C Master Protocol as defined in the PI 1.3 specification.
This protocol manipulates the I2C host controller to perform transactions as a master
on the I2C bus using the current state of any switches or multiplexers in the I2C bus.
Copyright (c) 2013, Intel Corporation. All rights reserved.<BR>
This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution. The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
@par Revision Reference:
This protocol is from PI Version 1.3.
**/
#ifndef __I2C_MASTER_H__
#define __I2C_MASTER_H__
#include <Pi/PiI2c.h>
#define EFI_I2C_MASTER_PROTOCOL_GUID { 0xcd72881f, 0x45b5, 0x4feb, { 0x98, 0xc8, 0x31, 0x3d, 0xa8, 0x11, 0x74, 0x62 }}
typedef struct _EFI_I2C_MASTER_PROTOCOL EFI_I2C_MASTER_PROTOCOL;
/**
Set the frequency for the I2C clock line.
This routine must be called at or below TPL_NOTIFY.
The software and controller do a best case effort of using the specified
frequency for the I2C bus. If the frequency does not match exactly then
the I2C master protocol selects the next lower frequency to avoid
exceeding the operating conditions for any of the I2C devices on the bus.
For example if 400 KHz was specified and the controller's divide network
only supports 402 KHz or 398 KHz then the I2C master protocol selects 398
KHz. If there are not lower frequencies available, then return
EFI_UNSUPPORTED.
@param[in] This Pointer to an EFI_I2C_MASTER_PROTOCOL structure
@param[in] BusClockHertz Pointer to the requested I2C bus clock frequency
in Hertz. Upon return this value contains the
actual frequency in use by the I2C controller.
@retval EFI_SUCCESS The bus frequency was set successfully.
@retval EFI_ALREADY_STARTED The controller is busy with another transaction.
@retval EFI_INVALID_PARAMETER BusClockHertz is NULL
@retval EFI_UNSUPPORTED The controller does not support this frequency.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_I2C_MASTER_PROTOCOL_SET_BUS_FREQUENCY) (
IN CONST EFI_I2C_MASTER_PROTOCOL *This,
IN OUT UINTN *BusClockHertz
);
/**
Reset the I2C controller and configure it for use
This routine must be called at or below TPL_NOTIFY.
The I2C controller is reset. The caller must call SetBusFrequench() after
calling Reset().
@param[in] This Pointer to an EFI_I2C_MASTER_PROTOCOL structure.
@retval EFI_SUCCESS The reset completed successfully.
@retval EFI_ALREADY_STARTED The controller is busy with another transaction.
@retval EFI_DEVICE_ERROR The reset operation failed.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_I2C_MASTER_PROTOCOL_RESET) (
IN CONST EFI_I2C_MASTER_PROTOCOL *This
);
/**
Start an I2C transaction on the host controller.
This routine must be called at or below TPL_NOTIFY. For synchronous
requests this routine must be called at or below TPL_CALLBACK.
This function initiates an I2C transaction on the controller. To
enable proper error handling by the I2C protocol stack, the I2C
master protocol does not support queuing but instead only manages
one I2C transaction at a time. This API requires that the I2C bus
is in the correct configuration for the I2C transaction.
The transaction is performed by sending a start-bit and selecting the
I2C device with the specified I2C slave address and then performing
the specified I2C operations. When multiple operations are requested
they are separated with a repeated start bit and the slave address.
The transaction is terminated with a stop bit.
When Event is NULL, StartRequest operates synchronously and returns
the I2C completion status as its return value.
When Event is not NULL, StartRequest synchronously returns EFI_SUCCESS
indicating that the I2C transaction was started asynchronously. The
transaction status value is returned in the buffer pointed to by
I2cStatus upon the completion of the I2C transaction when I2cStatus
is not NULL. After the transaction status is returned the Event is
signaled.
Note: The typical consumer of this API is the I2C host protocol.
Extreme care must be taken by other consumers of this API to prevent
confusing the third party I2C drivers due to a state change at the
I2C device which the third party I2C drivers did not initiate. I2C
platform specific code may use this API within these guidelines.
@param[in] This Pointer to an EFI_I2C_MASTER_PROTOCOL structure.
@param[in] SlaveAddress Address of the device on the I2C bus. Set the
I2C_ADDRESSING_10_BIT when using 10-bit addresses,
clear this bit for 7-bit addressing. Bits 0-6
are used for 7-bit I2C slave addresses and bits
0-9 are used for 10-bit I2C slave addresses.
@param[in] RequestPacket Pointer to an EFI_I2C_REQUEST_PACKET
structure describing the I2C transaction.
@param[in] Event Event to signal for asynchronous transactions,
NULL for asynchronous transactions
@param[out] I2cStatus Optional buffer to receive the I2C transaction
completion status
@retval EFI_SUCCESS The asynchronous transaction was successfully
started when Event is not NULL.
@retval EFI_SUCCESS The transaction completed successfully when
Event is NULL.
@retval EFI_ALREADY_STARTED The controller is busy with another transaction.
@retval EFI_BAD_BUFFER_SIZE The RequestPacket->LengthInBytes value is too
large.
@retval EFI_DEVICE_ERROR There was an I2C error (NACK) during the
transaction.
@retval EFI_INVALID_PARAMETER RequestPacket is NULL
@retval EFI_NOT_FOUND Reserved bit set in the SlaveAddress parameter
@retval EFI_NO_RESPONSE The I2C device is not responding to the slave
address. EFI_DEVICE_ERROR will be returned if
the controller cannot distinguish when the NACK
occurred.
@retval EFI_OUT_OF_RESOURCES Insufficient memory for I2C transaction
@retval EFI_UNSUPPORTED The controller does not support the requested
transaction.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_I2C_MASTER_PROTOCOL_START_REQUEST) (
IN CONST EFI_I2C_MASTER_PROTOCOL *This,
IN UINTN SlaveAddress,
IN EFI_I2C_REQUEST_PACKET *RequestPacket,
IN EFI_EVENT Event OPTIONAL,
OUT EFI_STATUS *I2cStatus OPTIONAL
);
///
/// I2C master mode protocol
///
/// This protocol manipulates the I2C host controller to perform transactions as a
/// master on the I2C bus using the current state of any switches or multiplexers
/// in the I2C bus.
///
struct _EFI_I2C_MASTER_PROTOCOL {
///
/// Set the clock frequency for the I2C bus.
///
EFI_I2C_MASTER_PROTOCOL_SET_BUS_FREQUENCY SetBusFrequency;
///
/// Reset the I2C host controller.
///
EFI_I2C_MASTER_PROTOCOL_RESET Reset;
///
/// Start an I2C transaction in master mode on the host controller.
///
EFI_I2C_MASTER_PROTOCOL_START_REQUEST StartRequest;
///
/// Pointer to an EFI_I2C_CONTROLLER_CAPABILITIES data structure containing
/// the capabilities of the I2C host controller.
///
CONST EFI_I2C_CONTROLLER_CAPABILITIES *I2cControllerCapabilities;
};
extern EFI_GUID gEfiI2cMasterProtocolGuid;
#endif // __I2C_MASTER_H__
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