Vlv2DeviceRefCodePkg/ValleyView2Soc/SouthCluster/Include/Protocol/I2cBus.h

   1 /** @file
   2   I2C bus interface
   3
   4   This layer provides I/O access to an I2C device.
   5
   6   Copyright (c) 2012, Intel Corporation. All rights reserved.
   7   SPDX-License-Identifier: BSD-2-Clause-Patent
   8
   9 **/
  10
  11 #ifndef __I2C_BUS_H__
  12 #define __I2C_BUS_H__
  13
  14 #include <Protocol/I2cHostMcg.h>
  15
  16 ///
  17 /// I2C bus protocol
  18 ///
  19 typedef struct _EFI_I2C_BUS_PROTOCOL  EFI_I2C_BUS_PROTOCOL;
  20
  21
  22 /**
  23   Perform an I2C operation on the device
  24
  25   This routine must be called at or below TPL_NOTIFY.  For synchronous
  26   requests this routine must be called at or below TPL_CALLBACK.
  27
  28   N.B. The typical consumers of this API are the third party I2C
  29   drivers.  Extreme care must be taken by other consumers of this
  30   API to prevent confusing the third party I2C drivers due to a
  31   state change at the I2C device which the third party I2C drivers
  32   did not initiate.  I2C platform drivers may use this API within
  33   these guidelines.
  34
  35   This routine queues an operation to the I2C controller for execution
  36   on the I2C bus.
  37
  38   As an upper layer driver writer, the following need to be provided
  39   to the platform vendor:
  40
  41   1.  ACPI CID value or string - this is used to connect the upper layer
  42       driver to the device.
  43   2.  Slave address array guidance when the I2C device uses more than one
  44       slave address.  This is used to access the blocks of hardware within
  45       the I2C device.
  46
  47   @param[in] This               Address of an EFI_I2C_BUS_PROTOCOL
  48                                 structure
  49   @param[in] SlaveAddressIndex  Index into an array of slave addresses for
  50                                 the I2C device.  The values in the array are
  51                                 specified by the board designer, with the
  52                                 I2C device driver writer providing the slave
  53                                 address order.
  54
  55                                 For devices that have a single slave address,
  56                                 this value must be zero.  If the I2C device
  57                                 uses more than one slave address then the third
  58                                 party (upper level) I2C driver writer needs to
  59                                 specify the order of entries in the slave address
  60                                 array.
  61
  62                                 \ref ThirdPartyI2cDrivers "Third Party I2C Drivers"
  63                                 section in I2cMaster.h.
  64   @param[in] Event              Event to set for asynchronous operations,
  65                                 NULL for synchronous operations
  66   @param[in] RequestPacket      Address of an EFI_I2C_REQUEST_PACKET
  67                                 structure describing the I2C operation
  68   @param[out] I2cStatus         Optional buffer to receive the I2C operation
  69                                 completion status
  70
  71   @retval EFI_SUCCESS           The operation completed successfully.
  72   @retval EFI_ABORTED           The request did not complete because the driver
  73                                 was shutdown.
  74   @retval EFI_ACCESS_DENIED     Invalid SlaveAddressIndex value
  75   @retval EFI_BAD_BUFFER_SIZE   The WriteBytes or ReadBytes buffer size is too large.
  76   @retval EFI_DEVICE_ERROR      There was an I2C error (NACK) during the operation.
  77                                 This could indicate the slave device is not present.
  78   @retval EFI_INVALID_PARAMETER RequestPacket is NULL
  79   @retval EFI_INVALID_PARAMETER TPL is too high
  80   @retval EFI_NO_RESPONSE       The I2C device is not responding to the
  81                                 slave address.  EFI_DEVICE_ERROR may also be
  82                                 returned if the controller can not distinguish
  83                                 when the NACK occurred.
  84   @retval EFI_NOT_FOUND         I2C slave address exceeds maximum address
  85   @retval EFI_NOT_READY         I2C bus is busy or operation pending, wait for
  86                                 the event and then read status pointed to by
  87                                 the request packet.
  88   @retval EFI_OUT_OF_RESOURCES  Insufficient memory for I2C operation
  89   @retval EFI_TIMEOUT           The transaction did not complete within an internally
  90                                 specified timeout period.
  91
  92 **/
  93 typedef
  94 EFI_STATUS
  95 (EFIAPI *EFI_I2C_BUS_START_REQUEST) (
  96   IN CONST EFI_I2C_BUS_PROTOCOL *This,
  97   IN UINTN SlaveAddressIndex,
  98   IN EFI_EVENT Event OPTIONAL,
  99   IN CONST EFI_I2C_REQUEST_PACKET *RequestPacket,
 100   OUT EFI_STATUS *I2cStatus OPTIONAL
 101   );
 102
 103 ///
 104 /// The I2C bus protocol enables access to a specific device on the I2C bus.
 105 ///
 106 /// Each I2C device is described as an ACPI node (HID, UID and CID) within the
 107 /// platform layer.  The I2C bus protocol enumerates the I2C devices in the
 108 /// platform and creates a unique handle and device path for each I2C device.
 109 ///
 110 /// I2C slave addressing is abstracted to validate addresses and limit operation
 111 /// to the specified I2C device.  The third party providing the I2C device support
 112 /// provides an ordered list of slave addresses for the I2C device to the team
 113 /// building the platform layer.  The platform team must preserve the order of the
 114 /// supplied list.  SlaveAddressCount is the number of entries in this list or
 115 /// array within the platform layer.  The third party device support references
 116 /// a slave address using an index into the list or array in the range of zero
 117 /// to SlaveAddressCount - 1.
 118 ///
 119 struct _EFI_I2C_BUS_PROTOCOL {
 120   ///
 121   /// Start an I2C operation on the bus
 122   ///
 123   EFI_I2C_BUS_START_REQUEST StartRequest;
 124
 125   ///
 126   /// The maximum number of slave addresses for the I2C device.  The caller may
 127   /// validate this value as a check on the platform layer's configuration.  Slave
 128   /// address selection uses an index value in the range of zero to SlaveAddressCount - 1.
 129   ///
 130   UINTN SlaveAddressCount;
 131
 132   ///
 133   /// Hardware revision - Matches the ACPI _HRV value
 134   ///
 135   /// The HardwareRevision value allows a single driver to support multiple hardware
 136   /// revisions and implement the necessary workarounds for limitations within the
 137   /// hardware.
 138   ///
 139   UINT32 HardwareRevision;
 140
 141   ///
 142   /// The maximum number of bytes the I2C host controller
 143   /// is able to receive from the I2C bus.
 144   ///
 145   UINT32 MaximumReceiveBytes;
 146
 147   ///
 148   /// The maximum number of bytes the I2C host controller
 149   /// is able to send on the I2C bus.
 150   ///
 151   UINT32 MaximumTransmitBytes;
 152
 153   ///
 154   /// The maximum number of bytes in the I2C bus transaction.
 155   ///
 156   UINT32 MaximumTotalBytes;
 157 };
 158
 159 ///
 160 /// GUID for the I2C bus protocol
 161 ///
 162 extern EFI_GUID gEfiI2cBusProtocolGuid;
 163
 164 #endif  //  __I2C_BUS_H__