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Diffstat (limited to 'MdePkg/Include/Protocol/I2cBusConfigurationManagement.h')
-rw-r--r-- | MdePkg/Include/Protocol/I2cBusConfigurationManagement.h | 171 |
1 files changed, 171 insertions, 0 deletions
diff --git a/MdePkg/Include/Protocol/I2cBusConfigurationManagement.h b/MdePkg/Include/Protocol/I2cBusConfigurationManagement.h new file mode 100644 index 0000000000..68000cf476 --- /dev/null +++ b/MdePkg/Include/Protocol/I2cBusConfigurationManagement.h @@ -0,0 +1,171 @@ +/** @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, 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_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__
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