Vlv2TbltDevicePkg/Include/Protocol/I2cBus.h

   1 /*++
   2
   3   Copyright (c) 2004  - 2014, Intel Corporation. All rights reserved.<BR>
   4
   5   This program and the accompanying materials are licensed and made available under
   6   the terms and conditions of the BSD License that accompanies this distribution.
   7   The full text of the license may be found at
   8   http://opensource.org/licenses/bsd-license.php.
   9
  10   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13
  14 **/
  15
  16 #ifndef __I2C_BUS_H__
  17 #define __I2C_BUS_H__
  18
  19 #include <Protocol/I2cHostMcg.h>
  20
  21 //
  22 // I2C bus protocol
  23 //
  24 typedef struct _EFI_I2C_BUS_PROTOCOL  EFI_I2C_BUS_PROTOCOL;
  25
  26
  27 /**
  28   Perform an I2C operation on the device
  29
  30   This routine must be called at or below TPL_NOTIFY.  For synchronous
  31   requests this routine must be called at or below TPL_CALLBACK.
  32
  33   N.B. The typical consumers of this API are the third party I2C
  34   drivers.  Extreme care must be taken by other consumers of this
  35   API to prevent confusing the third party I2C drivers due to a
  36   state change at the I2C device which the third party I2C drivers
  37   did not initiate.  I2C platform drivers may use this API within
  38   these guidelines.
  39
  40   This routine queues an operation to the I2C controller for execution
  41   on the I2C bus.
  42
  43   As an upper layer driver writer, the following need to be provided
  44   to the platform vendor:
  45
  46   1.  ACPI CID value or string - this is used to connect the upper layer
  47       driver to the device.
  48   2.  Slave address array guidance when the I2C device uses more than one
  49       slave address.  This is used to access the blocks of hardware within
  50       the I2C device.
  51
  52   @param[in] This               Address of an EFI_I2C_BUS_PROTOCOL
  53                                 structure
  54   @param[in] SlaveAddressIndex  Index into an array of slave addresses for
  55                                 the I2C device.  The values in the array are
  56                                 specified by the board designer, with the
  57                                 I2C device driver writer providing the slave
  58                                 address order.
  59
  60                                 For devices that have a single slave address,
  61                                 this value must be zero.  If the I2C device
  62                                 uses more than one slave address then the third
  63                                 party (upper level) I2C driver writer needs to
  64                                 specify the order of entries in the slave address
  65                                 array.
  66
  67                                 \ref ThirdPartyI2cDrivers "Third Party I2C Drivers"
  68                                 section in I2cMaster.h.
  69   @param[in] Event              Event to set for asynchronous operations,
  70                                 NULL for synchronous operations
  71   @param[in] RequestPacket      Address of an EFI_I2C_REQUEST_PACKET
  72                                 structure describing the I2C operation
  73   @param[out] I2cStatus         Optional buffer to receive the I2C operation
  74                                 completion status
  75
  76   @retval EFI_SUCCESS           The operation completed successfully.
  77   @retval EFI_ABORTED           The request did not complete because the driver
  78                                 was shutdown.
  79   @retval EFI_ACCESS_DENIED     Invalid SlaveAddressIndex value
  80   @retval EFI_BAD_BUFFER_SIZE   The WriteBytes or ReadBytes buffer size is too large.
  81   @retval EFI_DEVICE_ERROR      There was an I2C error (NACK) during the operation.
  82                                 This could indicate the slave device is not present.
  83   @retval EFI_INVALID_PARAMETER RequestPacket is NULL
  84   @retval EFI_INVALID_PARAMETER TPL is too high
  85   @retval EFI_NO_RESPONSE       The I2C device is not responding to the
  86                                 slave address.  EFI_DEVICE_ERROR may also be
  87                                 returned if the controller can not distinguish
  88                                 when the NACK occurred.
  89   @retval EFI_NOT_FOUND         I2C slave address exceeds maximum address
  90   @retval EFI_NOT_READY         I2C bus is busy or operation pending, wait for
  91                                 the event and then read status pointed to by
  92                                 the request packet.
  93   @retval EFI_OUT_OF_RESOURCES  Insufficient memory for I2C operation
  94   @retval EFI_TIMEOUT           The transaction did not complete within an internally
  95                                 specified timeout period.
  96
  97 **/
  98 typedef
  99 EFI_STATUS
 100 (EFIAPI *EFI_I2C_BUS_START_REQUEST) (
 101   IN CONST EFI_I2C_BUS_PROTOCOL *This,
 102   IN UINTN SlaveAddressIndex,
 103   IN EFI_EVENT Event OPTIONAL,
 104   IN CONST EFI_I2C_REQUEST_PACKET *RequestPacket,
 105   OUT EFI_STATUS *I2cStatus OPTIONAL
 106   );
 107
 108 //
 109 // The I2C bus protocol enables access to a specific device on the I2C bus.
 110 //
 111 // Each I2C device is described as an ACPI node (HID, UID and CID) within the
 112 // platform layer.  The I2C bus protocol enumerates the I2C devices in the
 113 // platform and creates a unique handle and device path for each I2C device.
 114 //
 115 // I2C slave addressing is abstracted to validate addresses and limit operation
 116 // to the specified I2C device.  The third party providing the I2C device support
 117 // provides an ordered list of slave addresses for the I2C device to the team
 118 // building the platform layer.  The platform team must preserve the order of the
 119 // supplied list.  SlaveAddressCount is the number of entries in this list or
 120 // array within the platform layer.  The third party device support references
 121 // a slave address using an index into the list or array in the range of zero
 122 // to SlaveAddressCount - 1.
 123 //
 124 struct _EFI_I2C_BUS_PROTOCOL {
 125   //
 126   // Start an I2C operation on the bus
 127   //
 128   EFI_I2C_BUS_START_REQUEST StartRequest;
 129
 130   //
 131   // The maximum number of slave addresses for the I2C device.  The caller may
 132   // validate this value as a check on the platform layer's configuration.  Slave
 133   // address selection uses an index value in the range of zero to SlaveAddressCount - 1.
 134   //
 135   UINTN SlaveAddressCount;
 136
 137   //
 138   // Hardware revision - Matches the ACPI _HRV value
 139   //
 140   // The HardwareRevision value allows a single driver to support multiple hardware
 141   // revisions and implement the necessary workarounds for limitations within the
 142   // hardware.
 143   //
 144   UINT32 HardwareRevision;
 145
 146   //
 147   // The maximum number of bytes the I2C host controller
 148   // is able to receive from the I2C bus.
 149   //
 150   UINT32 MaximumReceiveBytes;
 151
 152   //
 153   // The maximum number of bytes the I2C host controller
 154   // is able to send on the I2C bus.
 155   //
 156   UINT32 MaximumTransmitBytes;
 157
 158   //
 159   // The maximum number of bytes in the I2C bus transaction.
 160   //
 161   UINT32 MaximumTotalBytes;
 162 };
 163
 164 //
 165 // GUID for the I2C bus protocol
 166 //
 167 extern EFI_GUID gEfiI2cBusProtocolGuid;
 168
 169 #endif  //  __I2C_BUS_H__