[mirror_edk2.git] / OptionRomPkg / CirrusLogic5430Dxe / CirrusLogic5430I2c.c

/** @file\r
  I2C Bus implementation upon CirrusLogic.\r
\r
  Copyright (c) 2008 - 2009, Intel Corporation. All rights reserved.<BR>\r
  SPDX-License-Identifier: BSD-2-Clause-Patent\r
\r
**/\r
\r
#include "CirrusLogic5430.h"\r
#include "CirrusLogic5430I2c.h"\r
\r
#define SEQ_ADDRESS_REGISTER    0x3c4\r
#define SEQ_DATA_REGISTER       0x3c5\r
\r
#define I2C_CONTROL             0x08\r
#define I2CDAT_IN               7\r
#define I2CCLK_IN               2\r
#define I2CDAT_OUT              1\r
#define I2CCLK_OUT              0\r
\r
#define I2C_BUS_SPEED           100  //100kbps\r
\r
/**\r
  PCI I/O byte write function.\r
\r
  @param  PciIo        The pointer to PCI_IO_PROTOCOL.\r
  @param  Address      The bit map of I2C Data or I2C Clock pins.\r
  @param  Data         The date to write.\r
\r
**/\r
VOID\r
I2cOutb (\r
  EFI_PCI_IO_PROTOCOL    *PciIo,\r
  UINTN                  Address,\r
  UINT8                  Data\r
  )\r
{\r
  PciIo->Io.Write (\r
             PciIo,\r
             EfiPciIoWidthUint8,\r
             EFI_PCI_IO_PASS_THROUGH_BAR,\r
             Address,\r
             1,\r
             &Data\r
             );\r
}\r
/**\r
  PCI I/O byte read function.\r
\r
  @param  PciIo        The pointer to PCI_IO_PROTOCOL.\r
  @param  Address      The bit map of I2C Data or I2C Clock pins.\r
\r
  return byte value read from PCI I/O space.\r
\r
**/\r
UINT8\r
I2cInb (\r
  EFI_PCI_IO_PROTOCOL    *PciIo,\r
  UINTN                  Address\r
  )\r
{\r
  UINT8 Data;\r
\r
  PciIo->Io.Read (\r
             PciIo,\r
             EfiPciIoWidthUint8,\r
             EFI_PCI_IO_PASS_THROUGH_BAR,\r
             Address,\r
             1,\r
             &Data\r
             );\r
  return Data;\r
}\r
\r
/**\r
  Read status of I2C Data and I2C Clock Pins.\r
\r
  @param  PciIo        The pointer to PCI_IO_PROTOCOL.\r
  @param  Blt          The bit map of I2C Data or I2C Clock pins.\r
\r
  @retval 0            Low on I2C Data or I2C Clock Pin.\r
  @retval 1            High on I2C Data or I2C Clock Pin.\r
\r
**/\r
UINT8\r
I2cPinRead (\r
  EFI_PCI_IO_PROTOCOL    *PciIo,\r
  UINT8                  Bit\r
  )\r
{\r
  I2cOutb (PciIo, SEQ_ADDRESS_REGISTER, I2C_CONTROL);\r
  return (UINT8) ((I2cInb (PciIo, SEQ_DATA_REGISTER) >> Bit ) & 0xfe);\r
}\r
\r
\r
/**\r
  Set/Clear I2C Data and I2C Clock Pins.\r
\r
  @param  PciIo              The pointer to PCI_IO_PROTOCOL.\r
  @param  Blt                The bit map to controller I2C Data or I2C Clock pins.\r
  @param  Value              1 or 0 stands for Set or Clear I2C Data and I2C Clock Pins.\r
\r
**/\r
VOID\r
I2cPinWrite (\r
  EFI_PCI_IO_PROTOCOL    *PciIo,\r
  UINT8                  Bit,\r
  UINT8                  Value\r
  )\r
{\r
  UINT8        Byte;\r
  I2cOutb (PciIo, SEQ_ADDRESS_REGISTER, I2C_CONTROL);\r
  Byte = (UINT8) (I2cInb (PciIo, SEQ_DATA_REGISTER) & (UINT8) ~(1 << Bit)) ;\r
  Byte = (UINT8) (Byte | ((Value & 0x01) << Bit));\r
  I2cOutb (PciIo, SEQ_DATA_REGISTER, (UINT8) (Byte | 0x40));\r
  return;\r
}\r
\r
/**\r
  Read/write delay acoording to I2C Bus Speed.\r
\r
**/\r
VOID\r
I2cDelay (\r
  VOID\r
  )\r
{\r
  MicroSecondDelay (1000 / I2C_BUS_SPEED);\r
}\r
\r
/**\r
  Write a 8-bit data onto I2C Data Pin.\r
\r
  @param  PciIo              The pointer to PCI_IO_PROTOCOL.\r
  @param  Data               The byte data to write.\r
\r
**/\r
VOID\r
I2cSendByte (\r
  EFI_PCI_IO_PROTOCOL    *PciIo,\r
  UINT8                  Data\r
  )\r
{\r
  UINTN                  Index;\r
  //\r
  // Send byte data onto I2C Bus\r
  //\r
  for (Index = 0; Index < 8; Index --) {\r
    I2cPinWrite (PciIo, I2CDAT_OUT, (UINT8) (Data >> (7 - Index)));\r
    I2cPinWrite (PciIo, I2CCLK_OUT, 1);\r
    I2cDelay ();\r
    I2cPinWrite (PciIo, I2CCLK_OUT, 0);\r
  }\r
}\r
\r
/**\r
  Read a 8-bit data from I2C Data Pin.\r
\r
  @param  PciIo              The pointer to PCI_IO_PROTOCOL.\r
\r
  Return the byte data read from I2C Data Pin.\r
**/\r
UINT8\r
I2cReceiveByte (\r
  EFI_PCI_IO_PROTOCOL    *PciIo\r
  )\r
{\r
  UINT8          Data;\r
  UINTN          Index;\r
\r
  Data = 0;\r
  //\r
  // Read byte data from I2C Bus\r
  //\r
  for (Index = 0; Index < 8; Index --) {\r
    I2cPinWrite (PciIo, I2CCLK_OUT, 1);\r
    I2cDelay ();\r
    Data = (UINT8) (Data << 1);\r
    Data = (UINT8) (Data | I2cPinRead (PciIo, I2CDAT_IN));\r
    I2cPinWrite (PciIo, I2CCLK_OUT, 0);\r
  }\r
\r
  return Data;\r
}\r
\r
/**\r
  Receive an ACK signal from I2C Bus.\r
\r
  @param  PciIo              The pointer to PCI_IO_PROTOCOL.\r
\r
**/\r
BOOLEAN\r
I2cWaitAck (\r
  EFI_PCI_IO_PROTOCOL    *PciIo\r
  )\r
{\r
  //\r
  // Wait for ACK signal\r
  //\r
  I2cPinWrite (PciIo, I2CDAT_OUT, 1);\r
  I2cPinWrite (PciIo, I2CCLK_OUT, 1);\r
  I2cDelay ();\r
  if (I2cPinRead (PciIo, I2CDAT_IN) == 0) {\r
    I2cPinWrite (PciIo, I2CDAT_OUT, 1);\r
    return TRUE;\r
  } else {\r
    return FALSE;\r
  }\r
}\r
\r
/**\r
  Send an ACK signal onto I2C Bus.\r
\r
  @param  PciIo              The pointer to PCI_IO_PROTOCOL.\r
\r
**/\r
VOID\r
I2cSendAck (\r
  EFI_PCI_IO_PROTOCOL    *PciIo\r
  )\r
{\r
  I2cPinWrite (PciIo, I2CCLK_OUT, 1);\r
  I2cPinWrite (PciIo, I2CDAT_OUT, 1);\r
  I2cPinWrite (PciIo, I2CDAT_OUT, 0);\r
  I2cPinWrite (PciIo, I2CCLK_OUT, 0);\r
}\r
\r
/**\r
  Start a I2C transfer on I2C Bus.\r
\r
  @param  PciIo              The pointer to PCI_IO_PROTOCOL.\r
\r
**/\r
VOID\r
I2cStart (\r
  EFI_PCI_IO_PROTOCOL    *PciIo\r
  )\r
{\r
  //\r
  // Init CLK and DAT pins\r
  //\r
  I2cPinWrite (PciIo, I2CCLK_OUT, 1);\r
  I2cPinWrite (PciIo, I2CDAT_OUT, 1);\r
  //\r
  // Start a I2C transfer, set SDA low from high, when SCL is high\r
  //\r
  I2cPinWrite (PciIo, I2CDAT_OUT, 0);\r
  I2cPinWrite (PciIo, I2CCLK_OUT, 0);\r
}\r
\r
/**\r
  Stop a I2C transfer on I2C Bus.\r
\r
  @param  PciIo              The pointer to PCI_IO_PROTOCOL.\r
\r
**/\r
VOID\r
I2cStop (\r
  EFI_PCI_IO_PROTOCOL    *PciIo\r
  )\r
{\r
  //\r
  // Stop a I2C transfer, set SDA high from low, when SCL is high\r
  //\r
  I2cPinWrite (PciIo, I2CDAT_OUT, 0);\r
  I2cPinWrite (PciIo, I2CCLK_OUT, 1);\r
  I2cPinWrite (PciIo, I2CDAT_OUT, 1);\r
}\r
\r
/**\r
  Read one byte data on I2C Bus.\r
\r
  Read one byte data from the slave device connectet to I2C Bus.\r
  If Data is NULL, then ASSERT().\r
\r
  @param  PciIo              The pointer to PCI_IO_PROTOCOL.\r
  @param  DeviceAddress      Slave device's address.\r
  @param  RegisterAddress    The register address on slave device.\r
  @param  Data               The pointer to returned data if EFI_SUCCESS returned.\r
\r
  @retval EFI_DEVICE_ERROR\r
  @retval EFI_SUCCESS\r
\r
**/\r
EFI_STATUS\r
EFIAPI\r
I2cReadByte (\r
  EFI_PCI_IO_PROTOCOL    *PciIo,\r
  UINT8                  DeviceAddress,\r
  UINT8                  RegisterAddress,\r
  UINT8                  *Data\r
  )\r
{\r
  ASSERT (Data != NULL);\r
\r
  //\r
  // Start I2C transfer\r
  //\r
  I2cStart (PciIo);\r
\r
  //\r
  // Send slave address with enabling write flag\r
  //\r
  I2cSendByte (PciIo, (UINT8) (DeviceAddress & 0xfe));\r
\r
  //\r
  // Wait for ACK signal\r
  //\r
  if (I2cWaitAck (PciIo) == FALSE) {\r
    return EFI_DEVICE_ERROR;\r
  }\r
\r
  //\r
  // Send register address\r
  //\r
  I2cSendByte (PciIo, RegisterAddress);\r
\r
  //\r
  // Wait for ACK signal\r
  //\r
  if (I2cWaitAck (PciIo) == FALSE) {\r
    return EFI_DEVICE_ERROR;\r
  }\r
\r
  //\r
  // Send slave address with enabling read flag\r
  //\r
  I2cSendByte (PciIo, (UINT8) (DeviceAddress | 0x01));\r
\r
  //\r
  // Wait for ACK signal\r
  //\r
  if (I2cWaitAck (PciIo) == FALSE) {\r
    return EFI_DEVICE_ERROR;\r
  }\r
\r
  //\r
  // Read byte data from I2C Bus\r
  //\r
  *Data = I2cReceiveByte (PciIo);\r
\r
  //\r
  // Send ACK signal onto I2C Bus\r
  //\r
  I2cSendAck (PciIo);\r
\r
  //\r
  // Stop a I2C transfer\r
  //\r
  I2cStop (PciIo);\r
\r
  return EFI_SUCCESS;\r
}\r
\r
/**\r
  Write one byte data onto I2C Bus.\r
\r
  Write one byte data to the slave device connectet to I2C Bus.\r
  If Data is NULL, then ASSERT().\r
\r
  @param  PciIo              The pointer to PCI_IO_PROTOCOL.\r
  @param  DeviceAddress      Slave device's address.\r
  @param  RegisterAddress    The register address on slave device.\r
  @param  Data               The pointer to write data.\r
\r
  @retval EFI_DEVICE_ERROR\r
  @retval EFI_SUCCESS\r
\r
**/\r
EFI_STATUS\r
EFIAPI\r
I2cWriteByte (\r
  EFI_PCI_IO_PROTOCOL    *PciIo,\r
  UINT8                  DeviceAddress,\r
  UINT8                  RegisterAddress,\r
  UINT8                  *Data\r
  )\r
{\r
  ASSERT (Data != NULL);\r
\r
  I2cStart (PciIo);\r
  //\r
  // Send slave address with enabling write flag\r
  //\r
  I2cSendByte (PciIo, (UINT8) (DeviceAddress & 0xfe));\r
\r
  //\r
  // Wait for ACK signal\r
  //\r
  if (I2cWaitAck (PciIo) == FALSE) {\r
    return EFI_DEVICE_ERROR;\r
  }\r
\r
  //\r
  // Send register address\r
  //\r
  I2cSendByte (PciIo, RegisterAddress);\r
\r
  //\r
  // Wait for ACK signal\r
  //\r
  if (I2cWaitAck (PciIo) == FALSE) {\r
    return EFI_DEVICE_ERROR;\r
  }\r
\r
  //\r
  // Send byte data onto I2C Bus\r
  //\r
  I2cSendByte (PciIo, *Data);\r
\r
  //\r
  // Wait for ACK signal\r
  //\r
  if (I2cWaitAck (PciIo) == FALSE) {\r
    return EFI_DEVICE_ERROR;\r
  }\r
\r
  //\r
  // Stop a I2C transfer\r
  //\r
  I2cStop (PciIo);\r
\r
  return EFI_SUCCESS;\r
}\r
\r
\r
\r
Commit	Line	Data
9f354310	1	/** @file\r
	2	I2C Bus implementation upon CirrusLogic.\r
	3	\r
ac1ca104	4	Copyright (c) 2008 - 2009, Intel Corporation. All rights reserved.<BR>\r
96ae5934	5	SPDX-License-Identifier: BSD-2-Clause-Patent\r
9f354310	6	\r
	7	**/\r
	8	\r
	9	#include "CirrusLogic5430.h"\r
	10	#include "CirrusLogic5430I2c.h"\r
	11	\r
	12	#define SEQ_ADDRESS_REGISTER 0x3c4\r
	13	#define SEQ_DATA_REGISTER 0x3c5\r
	14	\r
	15	#define I2C_CONTROL 0x08\r
	16	#define I2CDAT_IN 7\r
	17	#define I2CCLK_IN 2\r
	18	#define I2CDAT_OUT 1\r
	19	#define I2CCLK_OUT 0\r
	20	\r
	21	#define I2C_BUS_SPEED 100 //100kbps\r
	22	\r
	23	/**\r
	24	PCI I/O byte write function.\r
	25	\r
	26	@param PciIo The pointer to PCI_IO_PROTOCOL.\r
	27	@param Address The bit map of I2C Data or I2C Clock pins.\r
	28	@param Data The date to write.\r
	29	\r
	30	**/\r
	31	VOID\r
	32	I2cOutb (\r
	33	EFI_PCI_IO_PROTOCOL *PciIo,\r
	34	UINTN Address,\r
	35	UINT8 Data\r
	36	)\r
	37	{\r
	38	PciIo->Io.Write (\r
	39	PciIo,\r
	40	EfiPciIoWidthUint8,\r
	41	EFI_PCI_IO_PASS_THROUGH_BAR,\r
	42	Address,\r
	43	1,\r
	44	&Data\r
	45	);\r
	46	}\r
	47	/**\r
	48	PCI I/O byte read function.\r
	49	\r
	50	@param PciIo The pointer to PCI_IO_PROTOCOL.\r
	51	@param Address The bit map of I2C Data or I2C Clock pins.\r
	52	\r
	53	return byte value read from PCI I/O space.\r
	54	\r
	55	**/\r
	56	UINT8\r
	57	I2cInb (\r
	58	EFI_PCI_IO_PROTOCOL *PciIo,\r
	59	UINTN Address\r
	60	)\r
	61	{\r
	62	UINT8 Data;\r
	63	\r
	64	PciIo->Io.Read (\r
	65	PciIo,\r
	66	EfiPciIoWidthUint8,\r
	67	EFI_PCI_IO_PASS_THROUGH_BAR,\r
	68	Address,\r
	69	1,\r
70	&Data\r
71	);\r
72	return Data;\r
73	}\r
74	\r
75	/**\r
76	Read status of I2C Data and I2C Clock Pins.\r
77	\r
78	@param PciIo The pointer to PCI_IO_PROTOCOL.\r
79	@param Blt The bit map of I2C Data or I2C Clock pins.\r
80	\r
81	@retval 0 Low on I2C Data or I2C Clock Pin.\r
82	@retval 1 High on I2C Data or I2C Clock Pin.\r
83	\r
84	**/\r
85	UINT8\r
86	I2cPinRead (\r
87	EFI_PCI_IO_PROTOCOL *PciIo,\r
88	UINT8 Bit\r
89	)\r
90	{\r
91	I2cOutb (PciIo, SEQ_ADDRESS_REGISTER, I2C_CONTROL);\r
92	return (UINT8) ((I2cInb (PciIo, SEQ_DATA_REGISTER) >> Bit ) & 0xfe);\r
93	}\r
94	\r
95	\r
96	/**\r
97	Set/Clear I2C Data and I2C Clock Pins.\r
98	\r
99	@param PciIo The pointer to PCI_IO_PROTOCOL.\r
100	@param Blt The bit map to controller I2C Data or I2C Clock pins.\r
101	@param Value 1 or 0 stands for Set or Clear I2C Data and I2C Clock Pins.\r
102	\r
103	**/\r
104	VOID\r
105	I2cPinWrite (\r
106	EFI_PCI_IO_PROTOCOL *PciIo,\r
107	UINT8 Bit,\r
108	UINT8 Value\r
109	)\r
110	{\r
111	UINT8 Byte;\r
112	I2cOutb (PciIo, SEQ_ADDRESS_REGISTER, I2C_CONTROL);\r
113	Byte = (UINT8) (I2cInb (PciIo, SEQ_DATA_REGISTER) & (UINT8) ~(1 << Bit)) ;\r
114	Byte = (UINT8) (Byte \| ((Value & 0x01) << Bit));\r
115	I2cOutb (PciIo, SEQ_DATA_REGISTER, (UINT8) (Byte \| 0x40));\r
116	return;\r
117	}\r
118	\r
119	/**\r
120	Read/write delay acoording to I2C Bus Speed.\r
121	\r
122	**/\r
123	VOID\r
124	I2cDelay (\r
125	VOID\r
126	)\r
127	{\r
128	MicroSecondDelay (1000 / I2C_BUS_SPEED);\r
129	}\r
130	\r
131	/**\r
132	Write a 8-bit data onto I2C Data Pin.\r
133	\r
134	@param PciIo The pointer to PCI_IO_PROTOCOL.\r
135	@param Data The byte data to write.\r
136	\r
137	**/\r
138	VOID\r
139	I2cSendByte (\r
140	EFI_PCI_IO_PROTOCOL *PciIo,\r
141	UINT8 Data\r
142	)\r
143	{\r
144	UINTN Index;\r
145	//\r
146	// Send byte data onto I2C Bus\r
147	//\r
148	for (Index = 0; Index < 8; Index --) {\r
149	I2cPinWrite (PciIo, I2CDAT_OUT, (UINT8) (Data >> (7 - Index)));\r
150	I2cPinWrite (PciIo, I2CCLK_OUT, 1);\r
151	I2cDelay ();\r
152	I2cPinWrite (PciIo, I2CCLK_OUT, 0);\r
153	}\r
154	}\r
155	\r
156	/**\r
157	Read a 8-bit data from I2C Data Pin.\r
158	\r
159	@param PciIo The pointer to PCI_IO_PROTOCOL.\r
160	\r
161	Return the byte data read from I2C Data Pin.\r
162	**/\r
163	UINT8\r
164	I2cReceiveByte (\r
165	EFI_PCI_IO_PROTOCOL *PciIo\r
166	)\r
167	{\r
168	UINT8 Data;\r
169	UINTN Index;\r
170	\r
171	Data = 0;\r
172	//\r
173	// Read byte data from I2C Bus\r
174	//\r
175	for (Index = 0; Index < 8; Index --) {\r
176	I2cPinWrite (PciIo, I2CCLK_OUT, 1);\r
177	I2cDelay ();\r
178	Data = (UINT8) (Data << 1);\r
179	Data = (UINT8) (Data \| I2cPinRead (PciIo, I2CDAT_IN));\r
180	I2cPinWrite (PciIo, I2CCLK_OUT, 0);\r
181	}\r
182	\r
183	return Data;\r
184	}\r
185	\r
186	/**\r
187	Receive an ACK signal from I2C Bus.\r
188	\r
189	@param PciIo The pointer to PCI_IO_PROTOCOL.\r
190	\r
191	**/\r
192	BOOLEAN\r
193	I2cWaitAck (\r
194	EFI_PCI_IO_PROTOCOL *PciIo\r
195	)\r
196	{\r
197	//\r
198	// Wait for ACK signal\r
199	//\r
200	I2cPinWrite (PciIo, I2CDAT_OUT, 1);\r
201	I2cPinWrite (PciIo, I2CCLK_OUT, 1);\r
202	I2cDelay ();\r
203	if (I2cPinRead (PciIo, I2CDAT_IN) == 0) {\r
204	I2cPinWrite (PciIo, I2CDAT_OUT, 1);\r
205	return TRUE;\r
206	} else {\r
207	return FALSE;\r
208	}\r
209	}\r
210	\r
211	/**\r
212	Send an ACK signal onto I2C Bus.\r
213	\r
214	@param PciIo The pointer to PCI_IO_PROTOCOL.\r
215	\r
216	**/\r
217	VOID\r
218	I2cSendAck (\r
219	EFI_PCI_IO_PROTOCOL *PciIo\r
220	)\r
221	{\r
222	I2cPinWrite (PciIo, I2CCLK_OUT, 1);\r
223	I2cPinWrite (PciIo, I2CDAT_OUT, 1);\r
224	I2cPinWrite (PciIo, I2CDAT_OUT, 0);\r
225	I2cPinWrite (PciIo, I2CCLK_OUT, 0);\r
226	}\r
227	\r
228	/**\r
229	Start a I2C transfer on I2C Bus.\r
230	\r
231	@param PciIo The pointer to PCI_IO_PROTOCOL.\r
232	\r
233	**/\r
234	VOID\r
235	I2cStart (\r
236	EFI_PCI_IO_PROTOCOL *PciIo\r
237	)\r
238	{\r
239	//\r
240	// Init CLK and DAT pins\r
241	//\r
242	I2cPinWrite (PciIo, I2CCLK_OUT, 1);\r
243	I2cPinWrite (PciIo, I2CDAT_OUT, 1);\r
244	//\r
245	// Start a I2C transfer, set SDA low from high, when SCL is high\r
246	//\r
247	I2cPinWrite (PciIo, I2CDAT_OUT, 0);\r
248	I2cPinWrite (PciIo, I2CCLK_OUT, 0);\r
249	}\r
250	\r
251	/**\r
252	Stop a I2C transfer on I2C Bus.\r
253	\r
254	@param PciIo The pointer to PCI_IO_PROTOCOL.\r
255	\r
256	**/\r
257	VOID\r
258	I2cStop (\r
259	EFI_PCI_IO_PROTOCOL *PciIo\r
260	)\r
261	{\r
262	//\r
263	// Stop a I2C transfer, set SDA high from low, when SCL is high\r
264	//\r
265	I2cPinWrite (PciIo, I2CDAT_OUT, 0);\r
266	I2cPinWrite (PciIo, I2CCLK_OUT, 1);\r
267	I2cPinWrite (PciIo, I2CDAT_OUT, 1);\r
268	}\r
269	\r
270	/**\r
271	Read one byte data on I2C Bus.\r
272	\r
273	Read one byte data from the slave device connectet to I2C Bus.\r
274	If Data is NULL, then ASSERT().\r
275	\r
276	@param PciIo The pointer to PCI_IO_PROTOCOL.\r
277	@param DeviceAddress Slave device's address.\r
278	@param RegisterAddress The register address on slave device.\r
279	@param Data The pointer to returned data if EFI_SUCCESS returned.\r
280	\r
281	@retval EFI_DEVICE_ERROR\r
282	@retval EFI_SUCCESS\r
283	\r
284	**/\r
285	EFI_STATUS\r
286	EFIAPI\r
287	I2cReadByte (\r
288	EFI_PCI_IO_PROTOCOL *PciIo,\r
289	UINT8 DeviceAddress,\r
290	UINT8 RegisterAddress,\r
291	UINT8 *Data\r
292	)\r
293	{\r
294	ASSERT (Data != NULL);\r
295	\r
296	//\r
297	// Start I2C transfer\r
298	//\r
299	I2cStart (PciIo);\r
300	\r
301	//\r
302	// Send slave address with enabling write flag\r
303	//\r
304	I2cSendByte (PciIo, (UINT8) (DeviceAddress & 0xfe));\r
305	\r
306	//\r
307	// Wait for ACK signal\r
308	//\r
309	if (I2cWaitAck (PciIo) == FALSE) {\r
310	return EFI_DEVICE_ERROR;\r
311	}\r
312	\r
313	//\r
314	// Send register address\r
315	//\r
316	I2cSendByte (PciIo, RegisterAddress);\r
317	\r
318	//\r
319	// Wait for ACK signal\r
320	//\r
321	if (I2cWaitAck (PciIo) == FALSE) {\r
322	return EFI_DEVICE_ERROR;\r
323	}\r
324	\r
325	//\r
326	// Send slave address with enabling read flag\r
327	//\r
328	I2cSendByte (PciIo, (UINT8) (DeviceAddress \| 0x01));\r
329	\r
330	//\r
331	// Wait for ACK signal\r
332	//\r
333	if (I2cWaitAck (PciIo) == FALSE) {\r
334	return EFI_DEVICE_ERROR;\r
335	}\r
336	\r
337	//\r
338	// Read byte data from I2C Bus\r
339	//\r
340	*Data = I2cReceiveByte (PciIo);\r
341	\r
342	//\r
343	// Send ACK signal onto I2C Bus\r
344	//\r
345	I2cSendAck (PciIo);\r
346	\r
347	//\r
348	// Stop a I2C transfer\r
349	//\r
350	I2cStop (PciIo);\r
351	\r
352	return EFI_SUCCESS;\r
353	}\r
354	\r
355	/**\r
356	Write one byte data onto I2C Bus.\r
357	\r
358	Write one byte data to the slave device connectet to I2C Bus.\r
359	If Data is NULL, then ASSERT().\r
360	\r
361	@param PciIo The pointer to PCI_IO_PROTOCOL.\r
362	@param DeviceAddress Slave device's address.\r
363	@param RegisterAddress The register address on slave device.\r
364	@param Data The pointer to write data.\r
365	\r
366	@retval EFI_DEVICE_ERROR\r
367	@retval EFI_SUCCESS\r
368	\r
369	**/\r
370	EFI_STATUS\r
371	EFIAPI\r
372	I2cWriteByte (\r
373	EFI_PCI_IO_PROTOCOL *PciIo,\r
374	UINT8 DeviceAddress,\r
375	UINT8 RegisterAddress,\r
376	UINT8 *Data\r
377	)\r
378	{\r
379	ASSERT (Data != NULL);\r
380	\r
381	I2cStart (PciIo);\r
382	//\r
383	// Send slave address with enabling write flag\r
384	//\r
385	I2cSendByte (PciIo, (UINT8) (DeviceAddress & 0xfe));\r
386	\r
387	//\r
388	// Wait for ACK signal\r
389	//\r
390	if (I2cWaitAck (PciIo) == FALSE) {\r
391	return EFI_DEVICE_ERROR;\r
392	}\r
393	\r
394	//\r
395	// Send register address\r
396	//\r
397	I2cSendByte (PciIo, RegisterAddress);\r
398	\r
399	//\r
400	// Wait for ACK signal\r
401	//\r
402	if (I2cWaitAck (PciIo) == FALSE) {\r
403	return EFI_DEVICE_ERROR;\r
404	}\r
405	\r
406	//\r
407	// Send byte data onto I2C Bus\r
408	//\r
409	I2cSendByte (PciIo, *Data);\r
410	\r
411	//\r
412	// Wait for ACK signal\r
413	//\r
414	if (I2cWaitAck (PciIo) == FALSE) {\r
415	return EFI_DEVICE_ERROR;\r
416	}\r
417	\r
418	//\r
419	// Stop a I2C transfer\r
420	//\r
421	I2cStop (PciIo);\r
422	\r
423	return EFI_SUCCESS;\r
424	}\r
425	\r
426	\r
427	\r