/** @file | |
I2C Host Protocol as defined in the PI 1.3 specification. | |
This protocol provides callers with the ability to do I/O transactions | |
to all of the devices on 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_HOST_H__ | |
#define __I2C_HOST_H__ | |
#include <Pi/PiI2c.h> | |
#define EFI_I2C_HOST_PROTOCOL_GUID { 0xa5aab9e3, 0xc727, 0x48cd, { 0x8b, 0xbf, 0x42, 0x72, 0x33, 0x85, 0x49, 0x48 }} | |
/// | |
/// I2C Host Protocol | |
/// | |
/// The I2C bus driver uses the services of the EFI_I2C_HOST_PROTOCOL | |
/// to produce an instance of the EFI_I2C_IO_PROTOCOL for each I2C | |
/// device on an I2C bus. | |
/// | |
/// The EFI_I2C_HOST_PROTOCOL exposes an asynchronous interface to | |
/// callers to perform transactions to any device on the I2C bus. | |
/// Internally, the I2C host protocol manages the flow of the I2C | |
/// transactions to the host controller, keeping them in FIFO order. | |
/// Prior to each transaction, the I2C host protocol ensures that the | |
/// switches and multiplexers are properly configured. The I2C host | |
/// protocol then starts the transaction on the host controller using | |
/// the EFI_I2C_MASTER_PROTOCOL. | |
/// | |
typedef struct _EFI_I2C_HOST_PROTOCOL EFI_I2C_HOST_PROTOCOL; | |
/** | |
Queue an I2C transaction for execution on the I2C controller. | |
This routine must be called at or below TPL_NOTIFY. For | |
synchronous requests this routine must be called at or below | |
TPL_CALLBACK. | |
The I2C host protocol uses the concept of I2C bus configurations | |
to describe the I2C bus. An I2C bus configuration is defined as | |
a unique setting of the multiplexers and switches in the I2C bus | |
which enable access to one or more I2C devices. When using a | |
switch to divide a bus, due to bus frequency differences, the | |
I2C bus configuration management protocol defines an I2C bus | |
configuration for the I2C devices on each side of the switch. | |
When using a multiplexer, the I2C bus configuration management | |
defines an I2C bus configuration for each of the selector values | |
required to control the multiplexer. See Figure 1 in the I2C -bus | |
specification and user manual for a complex I2C bus configuration. | |
The I2C host protocol processes all transactions in FIFO order. | |
Prior to performing the transaction, the I2C host protocol calls | |
EnableI2cBusConfiguration to reconfigure the switches and | |
multiplexers in the I2C bus enabling access to the specified I2C | |
device. The EnableI2cBusConfiguration also selects the I2C bus | |
frequency for the I2C device. After the I2C bus is configured, | |
the I2C host protocol calls the I2C master protocol to start the | |
I2C transaction. | |
If the I2C host protocol has pending I2C transactions queued when | |
the driver binding Stop() routine is called then the I2C host | |
protocol completes all of the pending I2C transactions by returning | |
EFI_ABORTED status. This notifies the upper layers allowing them | |
to take corrective action or prepare to stop. | |
When Event is NULL, QueueRequest() operates synchronously and | |
returns the I2C completion status as its return value. | |
When Event is not NULL, QueueRequest() synchronously returns | |
EFI_SUCCESS indicating that the asynchronously I2C transaction was | |
queued. The values above are returned in the buffer pointed to by | |
I2cStatus upon the completion of the I2C transaction when I2cStatus | |
is not NULL. | |
@param[in] This Pointer to an EFI_I2C_HOST_PROTOCOL structure. | |
@param[in] I2cBusConfiguration I2C bus configuration to access the I2C | |
device | |
@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] Event Event to signal for asynchronous transactions, | |
NULL for synchronous transactions | |
@param[in] RequestPacket Pointer to an EFI_I2C_REQUEST_PACKET structure | |
describing the I2C transaction | |
@param[out] I2cStatus Optional buffer to receive the I2C transaction | |
completion status | |
@retval EFI_SUCCESS The asynchronous transaction was successfully | |
queued when Event is not NULL. | |
@retval EFI_SUCCESS The transaction completed successfully when | |
Event is NULL. | |
@retval EFI_ABORTED The request did not complete because the | |
driver binding Stop() routine was called. | |
@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_MAPPING Invalid I2cBusConfiguration value | |
@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_HOST_PROTOCOL_QUEUE_REQUEST) ( | |
IN CONST EFI_I2C_HOST_PROTOCOL *This, | |
IN UINTN I2cBusConfiguration, | |
IN UINTN SlaveAddress, | |
IN EFI_EVENT Event OPTIONAL, | |
IN EFI_I2C_REQUEST_PACKET *RequestPacket, | |
OUT EFI_STATUS *I2cStatus OPTIONAL | |
); | |
/// | |
/// I2C Host Protocol | |
/// | |
struct _EFI_I2C_HOST_PROTOCOL { | |
/// | |
/// Queue an I2C transaction for execution on the I2C bus | |
/// | |
EFI_I2C_HOST_PROTOCOL_QUEUE_REQUEST QueueRequest; | |
/// | |
/// Pointer to an EFI_I2C_CONTROLLER_CAPABILITIES data structure | |
/// containing the capabilities of the I2C host controller. | |
/// | |
CONST EFI_I2C_CONTROLLER_CAPABILITIES *I2cControllerCapabilities; | |
}; | |
/// | |
/// Reference to variable defined in the .DEC file | |
/// | |
extern EFI_GUID gEfiI2cHostProtocolGuid; | |
#endif // __I2C_HOST_H__ |