iPXE
i2c.h
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1 #ifndef _IPXE_I2C_H
2 #define _IPXE_I2C_H
3 
4 /** @file
5  *
6  * I2C interface
7  *
8  */
9 
10 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
11 
12 #include <stdint.h>
13 #include <ipxe/bitbash.h>
14 
15 /** An I2C device
16  *
17  * An I2C device represents a specific slave device on an I2C bus. It
18  * is accessed via an I2C interface.
19  */
20 struct i2c_device {
21  /** Address of this device
22  *
23  * The actual address sent on the bus will look like
24  *
25  * <start> <device address> <word address overflow> <r/w>
26  *
27  * The "word address overflow" is any excess bits from the
28  * word address, i.e. any portion that does not fit within the
29  * defined word address length.
30  */
31  unsigned int dev_addr;
32  /** Device address length, in bytes
33  *
34  * This is the number of bytes that comprise the device
35  * address, defined to be the portion that terminates with the
36  * read/write bit.
37  */
38  unsigned int dev_addr_len;
39  /** Word adddress length, in bytes
40  *
41  * This is the number of bytes that comprise the word address,
42  * defined to be the portion that starts after the read/write
43  * bit and ends before the first data byte.
44  *
45  * For some devices, this length will be zero (i.e. the word
46  * address is contained entirely within the "word address
47  * overflow").
48  */
49  unsigned int word_addr_len;
50 };
51 
52 /** An I2C interface
53  *
54  * An I2C interface provides access to an I2C bus, via which I2C
55  * devices may be reached.
56  */
57 struct i2c_interface {
58  /**
59  * Read data from I2C device
60  *
61  * @v i2c I2C interface
62  * @v i2cdev I2C device
63  * @v offset Starting offset within the device
64  * @v data Data buffer
65  * @v len Length of data buffer
66  * @ret rc Return status code
67  */
68  int ( * read ) ( struct i2c_interface *i2c, struct i2c_device *i2cdev,
69  unsigned int offset, uint8_t *data,
70  unsigned int len );
71  /**
72  * Write data to I2C device
73  *
74  * @v i2c I2C interface
75  * @v i2cdev I2C device
76  * @v offset Starting offset within the device
77  * @v data Data buffer
78  * @v len Length of data buffer
79  * @ret rc Return status code
80  */
81  int ( * write ) ( struct i2c_interface *i2c, struct i2c_device *i2cdev,
82  unsigned int offset, const uint8_t *data,
83  unsigned int len );
84 };
85 
86 /** A bit-bashing I2C interface
87  *
88  * This provides a standardised way to construct I2C buses via a
89  * bit-bashing interface.
90  */
92  /** I2C interface */
94  /** Bit-bashing interface */
96 };
97 
98 /** Ten-bit address marker
99  *
100  * This value is ORed with the I2C device address to indicate a
101  * ten-bit address format on the bus.
102  */
103 #define I2C_TENBIT_ADDRESS 0x7800
104 
105 /** An I2C write command */
106 #define I2C_WRITE 0
107 
108 /** An I2C read command */
109 #define I2C_READ 1
110 
111 /** Bit indices used for I2C bit-bashing interface */
112 enum {
113  /** Serial clock */
115  /** Serial data */
117 };
118 
119 /** Delay required for bit-bashing operation */
120 #define I2C_UDELAY 5
121 
122 /** Maximum number of cycles to use when attempting a bus reset */
123 #define I2C_RESET_MAX_CYCLES 32
124 
125 /**
126  * Check presence of I2C device
127  *
128  * @v i2c I2C interface
129  * @v i2cdev I2C device
130  * @ret rc Return status code
131  *
132  * Checks for the presence of the device on the I2C bus by attempting
133  * a zero-length write.
134  */
135 static inline int i2c_check_presence ( struct i2c_interface *i2c,
136  struct i2c_device *i2cdev ) {
137  return i2c->write ( i2c, i2cdev, 0, NULL, 0 );
138 }
139 
140 extern int init_i2c_bit_basher ( struct i2c_bit_basher *i2cbit,
141  struct bit_basher_operations *bash_op );
142 
143 /**
144  * Initialise generic I2C EEPROM device
145  *
146  * @v i2cdev I2C device
147  */
148 static inline __always_inline void
149 init_i2c_eeprom ( struct i2c_device *i2cdev, unsigned int dev_addr ) {
150  i2cdev->dev_addr = dev_addr;
151  i2cdev->dev_addr_len = 1;
152  i2cdev->word_addr_len = 1;
153 }
154 
155 /**
156  * Initialise Atmel AT24C11
157  *
158  * @v i2cdev I2C device
159  */
160 static inline __always_inline void
161 init_at24c11 ( struct i2c_device *i2cdev ) {
162  /* This chip has no device address; it must be the only chip
163  * on the bus. The word address is contained entirely within
164  * the device address field.
165  */
166  i2cdev->dev_addr = 0;
167  i2cdev->dev_addr_len = 1;
168  i2cdev->word_addr_len = 0;
169 }
170 
171 #endif /* _IPXE_I2C_H */
int(* write)(struct i2c_interface *i2c, struct i2c_device *i2cdev, unsigned int offset, const uint8_t *data, unsigned int len)
Write data to I2C device.
Definition: i2c.h:81
Serial clock.
Definition: i2c.h:114
Bit-bashing operations.
Definition: bitbash.h:15
static int i2c_check_presence(struct i2c_interface *i2c, struct i2c_device *i2cdev)
Check presence of I2C device.
Definition: i2c.h:135
A bit-bashing I2C interface.
Definition: i2c.h:91
An I2C interface.
Definition: i2c.h:57
unsigned int dev_addr
Address of this device.
Definition: i2c.h:31
Serial data.
Definition: i2c.h:116
static __always_inline void init_i2c_eeprom(struct i2c_device *i2cdev, unsigned int dev_addr)
Initialise generic I2C EEPROM device.
Definition: i2c.h:149
int init_i2c_bit_basher(struct i2c_bit_basher *i2cbit, struct bit_basher_operations *bash_op)
Initialise I2C bit-bashing interface.
Definition: i2c_bit.c:387
struct i2c_interface i2c
I2C interface.
Definition: i2c.h:93
Bit-bashing interfaces.
static userptr_t size_t offset
Offset of the first segment within the content.
Definition: deflate.h:259
struct bit_basher basher
Bit-bashing interface.
Definition: i2c.h:95
A bit-bashing interface.
Definition: bitbash.h:55
#define __always_inline
Declare a function to be always inline.
Definition: compiler.h:611
unsigned char uint8_t
Definition: stdint.h:10
static __always_inline void init_at24c11(struct i2c_device *i2cdev)
Initialise Atmel AT24C11.
Definition: i2c.h:161
int(* read)(struct i2c_interface *i2c, struct i2c_device *i2cdev, unsigned int offset, uint8_t *data, unsigned int len)
Read data from I2C device.
Definition: i2c.h:68
unsigned int word_addr_len
Word adddress length, in bytes.
Definition: i2c.h:49
uint32_t len
Length.
Definition: ena.h:14
struct arbelprm_port_state_change_st data
Message.
Definition: arbel.h:12
unsigned int dev_addr_len
Device address length, in bytes.
Definition: i2c.h:38
#define NULL
NULL pointer (VOID *)
Definition: Base.h:362
An I2C device.
Definition: i2c.h:20
FILE_LICENCE(GPL2_OR_LATER_OR_UBDL)