mirror of https://github.com/acidanthera/audk.git
448 lines
9.1 KiB
C
448 lines
9.1 KiB
C
/** @file
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I2C Bus Libary implementation upon CirrusLogic.
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Copyright (c) 2008, Intel Corporation
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All rights reserved. This program and the accompanying materials
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are licensed and made available under the terms and conditions of the BSD License
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which accompanies this distribution. The full text of the license may be found at
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http://opensource.org/licenses/bsd-license.php
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THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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**/
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#include <PiDxe.h>
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#include <Library/DxeI2cLib.h>
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#include <Library/TimerLib.h>
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#include <Library/DebugLib.h>
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#define SEQ_ADDRESS_REGISTER 0x3c4
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#define SEQ_DATA_REGISTER 0x3c5
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#define I2C_CONTROL 0x08
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#define I2CDAT_IN 7
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#define I2CCLK_IN 2
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#define I2CDAT_OUT 1
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#define I2CCLK_OUT 0
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#define I2C_BUS_SPEED 100 //100kbps
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/**
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PCI I/O byte write function.
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@param PciIo The pointer to PCI_IO_PROTOCOL.
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@param Address The bit map of I2C Data or I2C Clock pins.
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@param Data The date to write.
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**/
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STATIC
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VOID
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outb (
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EFI_PCI_IO_PROTOCOL *PciIo,
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UINTN Address,
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UINT8 Data
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)
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{
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PciIo->Io.Write (
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PciIo,
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EfiPciIoWidthUint8,
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EFI_PCI_IO_PASS_THROUGH_BAR,
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Address,
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1,
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&Data
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);
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}
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/**
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PCI I/O byte read function.
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@param PciIo The pointer to PCI_IO_PROTOCOL.
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@param Address The bit map of I2C Data or I2C Clock pins.
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return byte value read from PCI I/O space.
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**/
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STATIC
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UINT8
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inb (
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EFI_PCI_IO_PROTOCOL *PciIo,
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UINTN Address
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)
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{
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UINT8 Data;
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PciIo->Io.Read (
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PciIo,
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EfiPciIoWidthUint8,
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EFI_PCI_IO_PASS_THROUGH_BAR,
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Address,
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1,
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&Data
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);
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return Data;
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}
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/**
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Read status of I2C Data and I2C Clock Pins.
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@param PciIo The pointer to PCI_IO_PROTOCOL.
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@param Blt The bit map of I2C Data or I2C Clock pins.
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@retval 0 Low on I2C Data or I2C Clock Pin.
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@retval 1 High on I2C Data or I2C Clock Pin.
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**/
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STATIC
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UINT8
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I2cPinRead (
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EFI_PCI_IO_PROTOCOL *PciIo,
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UINT8 Bit
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)
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{
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outb (PciIo, SEQ_ADDRESS_REGISTER, I2C_CONTROL);
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return (UINT8) ((inb (PciIo, SEQ_DATA_REGISTER) >> Bit ) & 0xfe);
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}
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/**
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Set/Clear I2C Data and I2C Clock Pins.
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@param PciIo The pointer to PCI_IO_PROTOCOL.
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@param Blt The bit map to controller I2C Data or I2C Clock pins.
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@param Value 1 or 0 stands for Set or Clear I2C Data and I2C Clock Pins.
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**/
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STATIC
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VOID
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I2cPinWrite (
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EFI_PCI_IO_PROTOCOL *PciIo,
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UINT8 Bit,
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UINT8 Value
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)
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{
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UINT8 Byte;
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outb (PciIo, SEQ_ADDRESS_REGISTER, I2C_CONTROL);
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Byte = (UINT8) (inb (PciIo, SEQ_DATA_REGISTER) & (UINT8) ~(1 << Bit)) ;
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Byte = (UINT8) (Byte | ((Value & 0x01) << Bit));
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outb (PciIo, SEQ_DATA_REGISTER, (UINT8) (Byte | 0x40));
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return;
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}
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/**
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Read/write delay acoording to I2C Bus Speed.
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**/
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STATIC
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VOID
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I2cDelay (
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VOID
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)
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{
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MicroSecondDelay (1000 / I2C_BUS_SPEED);
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}
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/**
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Write a 8-bit data onto I2C Data Pin.
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@param PciIo The pointer to PCI_IO_PROTOCOL.
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@param Data The byte data to write.
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**/
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STATIC
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VOID
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I2cSendByte (
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EFI_PCI_IO_PROTOCOL *PciIo,
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UINT8 Data
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)
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{
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UINTN Index;
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//
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// Send byte data onto I2C Bus
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//
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for (Index = 0; Index < 8; Index --) {
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I2cPinWrite (PciIo, I2CDAT_OUT, (UINT8) (Data >> (7 - Index)));
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I2cPinWrite (PciIo, I2CCLK_OUT, 1);
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I2cDelay ();
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I2cPinWrite (PciIo, I2CCLK_OUT, 0);
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}
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}
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/**
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Read a 8-bit data from I2C Data Pin.
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@param PciIo The pointer to PCI_IO_PROTOCOL.
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Return the byte data read from I2C Data Pin.
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**/
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STATIC
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UINT8
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I2cReceiveByte (
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EFI_PCI_IO_PROTOCOL *PciIo
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)
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{
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UINT8 Data;
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UINTN Index;
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Data = 0;
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//
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// Read byte data from I2C Bus
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//
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for (Index = 0; Index < 8; Index --) {
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I2cPinWrite (PciIo, I2CCLK_OUT, 1);
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I2cDelay ();
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Data = (UINT8) (Data << 1);
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Data = (UINT8) (Data | I2cPinRead (PciIo, I2CDAT_IN));
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I2cPinWrite (PciIo, I2CCLK_OUT, 0);
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}
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return Data;
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}
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/**
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Receive an ACK signal from I2C Bus.
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@param PciIo The pointer to PCI_IO_PROTOCOL.
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**/
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STATIC
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BOOLEAN
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I2cWaitAck (
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EFI_PCI_IO_PROTOCOL *PciIo
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)
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{
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//
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// Wait for ACK signal
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//
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I2cPinWrite (PciIo, I2CDAT_OUT, 1);
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I2cPinWrite (PciIo, I2CCLK_OUT, 1);
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I2cDelay ();
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if (I2cPinRead (PciIo, I2CDAT_IN) == 0) {
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I2cPinWrite (PciIo, I2CDAT_OUT, 1);
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return TRUE;
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} else {
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return FALSE;
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}
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}
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/**
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Send an ACK signal onto I2C Bus.
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@param PciIo The pointer to PCI_IO_PROTOCOL.
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**/
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STATIC
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VOID
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I2cSendAck (
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EFI_PCI_IO_PROTOCOL *PciIo
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)
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{
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I2cPinWrite (PciIo, I2CCLK_OUT, 1);
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I2cPinWrite (PciIo, I2CDAT_OUT, 1);
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I2cPinWrite (PciIo, I2CDAT_OUT, 0);
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I2cPinWrite (PciIo, I2CCLK_OUT, 0);
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}
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/**
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Start a I2C transfer on I2C Bus.
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@param PciIo The pointer to PCI_IO_PROTOCOL.
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**/
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STATIC
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VOID
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I2cStart (
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EFI_PCI_IO_PROTOCOL *PciIo
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)
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{
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//
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// Init CLK and DAT pins
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//
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I2cPinWrite (PciIo, I2CCLK_OUT, 1);
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I2cPinWrite (PciIo, I2CDAT_OUT, 1);
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//
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// Start a I2C transfer, set SDA low from high, when SCL is high
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//
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I2cPinWrite (PciIo, I2CDAT_OUT, 0);
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I2cPinWrite (PciIo, I2CCLK_OUT, 0);
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}
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/**
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Stop a I2C transfer on I2C Bus.
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@param PciIo The pointer to PCI_IO_PROTOCOL.
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**/
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STATIC
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VOID
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I2cStop (
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EFI_PCI_IO_PROTOCOL *PciIo
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)
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{
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//
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// Stop a I2C transfer, set SDA high from low, when SCL is high
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//
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I2cPinWrite (PciIo, I2CDAT_OUT, 0);
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I2cPinWrite (PciIo, I2CCLK_OUT, 1);
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I2cPinWrite (PciIo, I2CDAT_OUT, 1);
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}
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/**
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Read one byte data on I2C Bus.
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Read one byte data from the slave device connectet to I2C Bus.
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If Data is NULL, then ASSERT().
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@param PciIo The pointer to PCI_IO_PROTOCOL.
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@param DeviceAddress Slave device's address.
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@param RegisterAddress The register address on slave device.
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@param Data The pointer to returned data if EFI_SUCCESS returned.
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@retval EFI_DEVICE_ERROR
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@retval EFI_SUCCESS
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**/
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EFI_STATUS
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EFIAPI
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I2cReadByte (
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EFI_PCI_IO_PROTOCOL *PciIo,
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UINT8 DeviceAddress,
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UINT8 RegisterAddress,
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UINT8 *Data
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)
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{
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ASSERT (Data != NULL);
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//
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// Start I2C transfer
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//
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I2cStart (PciIo);
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//
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// Send slave address with enabling write flag
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//
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I2cSendByte (PciIo, (UINT8) (DeviceAddress & 0xfe));
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//
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// Wait for ACK signal
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//
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if (I2cWaitAck (PciIo) == FALSE) {
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return EFI_DEVICE_ERROR;
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}
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//
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// Send register address
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//
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I2cSendByte (PciIo, RegisterAddress);
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//
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// Wait for ACK signal
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//
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if (I2cWaitAck (PciIo) == FALSE) {
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return EFI_DEVICE_ERROR;
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}
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//
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// Send slave address with enabling read flag
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//
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I2cSendByte (PciIo, (UINT8) (DeviceAddress | 0x01));
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//
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// Wait for ACK signal
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//
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if (I2cWaitAck (PciIo) == FALSE) {
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return EFI_DEVICE_ERROR;
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}
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//
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// Read byte data from I2C Bus
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//
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*Data = I2cReceiveByte (PciIo);
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//
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// Send ACK signal onto I2C Bus
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//
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I2cSendAck (PciIo);
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//
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// Stop a I2C transfer
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//
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I2cStop (PciIo);
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return EFI_SUCCESS;
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}
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/**
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Write one byte data onto I2C Bus.
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Write one byte data to the slave device connectet to I2C Bus.
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If Data is NULL, then ASSERT().
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@param PciIo The pointer to PCI_IO_PROTOCOL.
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@param DeviceAddress Slave device's address.
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@param RegisterAddress The register address on slave device.
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@param Data The pointer to write data.
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@retval EFI_DEVICE_ERROR
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@retval EFI_SUCCESS
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**/
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EFI_STATUS
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EFIAPI
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I2cWriteByte (
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EFI_PCI_IO_PROTOCOL *PciIo,
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UINT8 DeviceAddress,
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UINT8 RegisterAddress,
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UINT8 *Data
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)
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{
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ASSERT (Data != NULL);
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I2cStart (PciIo);
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//
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// Send slave address with enabling write flag
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//
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I2cSendByte (PciIo, (UINT8) (DeviceAddress & 0xfe));
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//
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// Wait for ACK signal
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//
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if (I2cWaitAck (PciIo) == FALSE) {
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return EFI_DEVICE_ERROR;
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}
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//
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// Send register address
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//
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I2cSendByte (PciIo, RegisterAddress);
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//
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// Wait for ACK signal
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//
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if (I2cWaitAck (PciIo) == FALSE) {
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return EFI_DEVICE_ERROR;
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}
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//
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// Send byte data onto I2C Bus
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//
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I2cSendByte (PciIo, *Data);
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//
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// Wait for ACK signal
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//
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if (I2cWaitAck (PciIo) == FALSE) {
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return EFI_DEVICE_ERROR;
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}
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//
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// Stop a I2C transfer
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//
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I2cStop (PciIo);
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return EFI_SUCCESS;
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}
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