mirror of
https://github.com/CloverHackyColor/CloverBootloader.git
synced 2024-12-22 16:08:07 +01:00
166 lines
8.1 KiB
C
166 lines
8.1 KiB
C
/** @file
|
|
I2C Bus Configuration Management Protocol as defined in the PI 1.3 specification.
|
|
|
|
The EFI I2C bus configuration management protocol provides platform specific
|
|
services that allow the I2C host protocol to reconfigure the switches and multiplexers
|
|
and set the clock frequency for the I2C bus. This protocol also enables the I2C host protocol
|
|
to reset an I2C device which may be locking up the I2C bus by holding the clock or data line low.
|
|
|
|
Copyright (c) 2013 - 2018, Intel Corporation. All rights reserved.<BR>
|
|
SPDX-License-Identifier: BSD-2-Clause-Patent
|
|
|
|
@par Revision Reference:
|
|
This protocol is from PI Version 1.3.
|
|
|
|
**/
|
|
|
|
#ifndef __I2C_BUS_CONFIGURATION_MANAGEMENT_H__
|
|
#define __I2C_BUS_CONFIGURATION_MANAGEMENT_H__
|
|
|
|
#define EFI_I2C_BUS_CONFIGURATION_MANAGEMENT_PROTOCOL_GUID \
|
|
{ 0x55b71fb5, 0x17c6, 0x410e, { 0xb5, 0xbd, 0x5f, 0xa2, 0xe3, 0xd4, 0x46, 0x6b }}
|
|
|
|
///
|
|
/// I2C bus configuration management protocol
|
|
///
|
|
/// The EFI I2C bus configuration management protocol provides platform
|
|
/// specific services that allow the I2C host protocol to reconfigure the
|
|
/// switches and multiplexers and set the clock frequency for the I2C bus.
|
|
/// This protocol also enables the I2C host protocol to reset an I2C device
|
|
/// which may be locking up the I2C bus by holding the clock or data line
|
|
/// low.
|
|
///
|
|
/// The I2C protocol stack uses the concept of an I2C bus configuration as
|
|
/// a way to describe a particular state of the switches and multiplexers
|
|
/// in the I2C bus.
|
|
///
|
|
/// A simple I2C bus does not have any multiplexers or switches is described
|
|
/// to the I2C protocol stack with a single I2C bus configuration which
|
|
/// specifies the I2C bus frequency.
|
|
///
|
|
/// An I2C bus with switches and multiplexers use an I2C bus configuration
|
|
/// to describe each of the unique settings for the switches and multiplexers
|
|
/// and the I2C bus frequency. However the I2C bus configuration management
|
|
/// protocol only needs to define the I2C bus configurations that the software
|
|
/// uses, which may be a subset of the total.
|
|
///
|
|
/// The I2C bus configuration description includes a list of I2C devices
|
|
/// which may be accessed when this I2C bus configuration is enabled. I2C
|
|
/// devices before a switch or multiplexer must be included in one I2C bus
|
|
/// configuration while I2C devices after a switch or multiplexer are on
|
|
/// another I2C bus configuration.
|
|
///
|
|
/// The I2C bus configuration management protocol is an optional protocol.
|
|
/// When the I2C bus configuration protocol is not defined the I2C host
|
|
/// protocol does not start and the I2C master protocol may be used for
|
|
/// other purposes such as SMBus traffic. When the I2C bus configuration
|
|
/// protocol is available, the I2C host protocol uses the I2C bus
|
|
/// configuration protocol to call into the platform specific code to set
|
|
/// the switches and multiplexers and set the maximum I2C bus frequency.
|
|
///
|
|
/// The platform designers determine the maximum I2C bus frequency by
|
|
/// selecting a frequency which supports all of the I2C devices on the
|
|
/// I2C bus for the setting of switches and multiplexers. The platform
|
|
/// designers must validate this against the I2C device data sheets and
|
|
/// any limits of the I2C controller or bus length.
|
|
///
|
|
/// During I2C device enumeration, the I2C bus driver retrieves the I2C
|
|
/// bus configuration that must be used to perform I2C transactions to
|
|
/// each I2C device. This I2C bus configuration value is passed into
|
|
/// the I2C host protocol to identify the I2C bus configuration required
|
|
/// to access a specific I2C device. The I2C host protocol calls
|
|
/// EnableBusConfiguration() to set the switches and multiplexers in the
|
|
/// I2C bus and the I2C clock frequency. The I2C host protocol may
|
|
/// optimize calls to EnableBusConfiguration() by only making the call
|
|
/// when the I2C bus configuration value changes between I2C requests.
|
|
///
|
|
/// When I2C transactions are required on the same I2C bus to change the
|
|
/// state of multiplexers or switches, the I2C master protocol must be
|
|
/// used to perform the necessary I2C transactions.
|
|
///
|
|
/// It is up to the platform specific code to choose the proper I2C bus
|
|
/// configuration when ExitBootServices() is called. Some operating systems
|
|
/// are not able to manage the I2C bus configurations and must use the I2C
|
|
/// bus configuration that is established by the platform firmware before
|
|
/// ExitBootServices() returns.
|
|
///
|
|
typedef struct _EFI_I2C_BUS_CONFIGURATION_MANAGEMENT_PROTOCOL EFI_I2C_BUS_CONFIGURATION_MANAGEMENT_PROTOCOL;
|
|
|
|
|
|
/**
|
|
Enable access to an I2C bus configuration.
|
|
|
|
This routine must be called at or below TPL_NOTIFY. For synchronous
|
|
requests this routine must be called at or below TPL_CALLBACK.
|
|
|
|
Reconfigure the switches and multiplexers in the I2C bus to enable
|
|
access to a specific I2C bus configuration. Also select the maximum
|
|
clock frequency for this I2C bus configuration.
|
|
|
|
This routine uses the I2C Master protocol to perform I2C transactions
|
|
on the local bus. This eliminates any recursion in the I2C stack for
|
|
configuration transactions on the same I2C bus. This works because the
|
|
local I2C bus is idle while the I2C bus configuration is being enabled.
|
|
|
|
If I2C transactions must be performed on other I2C busses, then the
|
|
EFI_I2C_HOST_PROTOCOL, the EFI_I2C_IO_PROTCOL, or a third party I2C
|
|
driver interface for a specific device must be used. This requirement
|
|
is because the I2C host protocol controls the flow of requests to the
|
|
I2C controller. Use the EFI_I2C_HOST_PROTOCOL when the I2C device is
|
|
not enumerated by the EFI_I2C_ENUMERATE_PROTOCOL. Use a protocol
|
|
produced by a third party driver when it is available or the
|
|
EFI_I2C_IO_PROTOCOL when the third party driver is not available but
|
|
the device is enumerated with the EFI_I2C_ENUMERATE_PROTOCOL.
|
|
|
|
When Event is NULL, EnableI2cBusConfiguration operates synchronously
|
|
and returns the I2C completion status as its return value.
|
|
|
|
@param[in] This Pointer to an EFI_I2C_BUS_CONFIGURATION_MANAGEMENT_PROTOCOL
|
|
structure.
|
|
@param[in] I2cBusConfiguration Index of an I2C bus configuration. All
|
|
values in the range of zero to N-1 are
|
|
valid where N is the total number of I2C
|
|
bus configurations for an I2C bus.
|
|
@param[in] Event Event to signal when the transaction is complete
|
|
@param[out] I2cStatus Buffer to receive the transaction status.
|
|
|
|
@return When Event is NULL, EnableI2cBusConfiguration operates synchrouously
|
|
and returns the I2C completion status as its return value. In this case it is
|
|
recommended to use NULL for I2cStatus. The values returned from
|
|
EnableI2cBusConfiguration are:
|
|
|
|
@retval EFI_SUCCESS The asynchronous bus configuration request
|
|
was successfully started when Event is not
|
|
NULL.
|
|
@retval EFI_SUCCESS The bus configuration request completed
|
|
successfully when Event is NULL.
|
|
@retval EFI_DEVICE_ERROR The bus configuration failed.
|
|
@retval EFI_NO_MAPPING Invalid I2cBusConfiguration value
|
|
|
|
**/
|
|
typedef
|
|
EFI_STATUS
|
|
(EFIAPI *EFI_I2C_BUS_CONFIGURATION_MANAGEMENT_PROTOCOL_ENABLE_I2C_BUS_CONFIGURATION) (
|
|
IN CONST EFI_I2C_BUS_CONFIGURATION_MANAGEMENT_PROTOCOL *This,
|
|
IN UINTN I2cBusConfiguration,
|
|
IN EFI_EVENT Event OPTIONAL,
|
|
IN EFI_STATUS *I2cStatus OPTIONAL
|
|
);
|
|
|
|
///
|
|
/// I2C bus configuration management protocol
|
|
///
|
|
struct _EFI_I2C_BUS_CONFIGURATION_MANAGEMENT_PROTOCOL {
|
|
///
|
|
/// Enable an I2C bus configuration for use.
|
|
///
|
|
EFI_I2C_BUS_CONFIGURATION_MANAGEMENT_PROTOCOL_ENABLE_I2C_BUS_CONFIGURATION EnableI2cBusConfiguration;
|
|
};
|
|
|
|
///
|
|
/// Reference to variable defined in the .DEC file
|
|
///
|
|
extern EFI_GUID gEfiI2cBusConfigurationManagementProtocolGuid;
|
|
|
|
#endif // __I2C_BUS_CONFIGURATION_MANAGEMENT_H__
|