2006-06-11 02:57:00 +02:00
|
|
|
#ifndef _GPXE_I2C_H
|
|
|
|
#define _GPXE_I2C_H
|
|
|
|
|
|
|
|
/** @file
|
|
|
|
*
|
|
|
|
* I2C interface
|
|
|
|
*
|
|
|
|
*/
|
|
|
|
|
|
|
|
#include <stdint.h>
|
2008-10-01 20:15:07 +02:00
|
|
|
#include <gpxe/bitbash.h>
|
2006-06-11 02:57:00 +02:00
|
|
|
|
|
|
|
/** An I2C device
|
|
|
|
*
|
|
|
|
* An I2C device represents a specific slave device on an I2C bus. It
|
|
|
|
* is accessed via an I2C interface.
|
|
|
|
*/
|
|
|
|
struct i2c_device {
|
2008-10-01 20:15:07 +02:00
|
|
|
/** Address of this device
|
|
|
|
*
|
|
|
|
* The actual address sent on the bus will look like
|
|
|
|
*
|
|
|
|
* <start> <device address> <word address overflow> <r/w>
|
|
|
|
*
|
|
|
|
* The "word address overflow" is any excess bits from the
|
|
|
|
* word address, i.e. any portion that does not fit within the
|
|
|
|
* defined word address length.
|
|
|
|
*/
|
|
|
|
unsigned int dev_addr;
|
|
|
|
/** Device address length, in bytes
|
|
|
|
*
|
|
|
|
* This is the number of bytes that comprise the device
|
|
|
|
* address, defined to be the portion that terminates with the
|
|
|
|
* read/write bit.
|
|
|
|
*/
|
|
|
|
unsigned int dev_addr_len;
|
|
|
|
/** Word adddress length, in bytes
|
|
|
|
*
|
|
|
|
* This is the number of bytes that comprise the word address,
|
|
|
|
* defined to be the portion that starts after the read/write
|
|
|
|
* bit and ends before the first data byte.
|
|
|
|
*
|
|
|
|
* For some devices, this length will be zero (i.e. the word
|
|
|
|
* address is contained entirely within the "word address
|
|
|
|
* overflow").
|
|
|
|
*/
|
|
|
|
unsigned int word_addr_len;
|
2006-06-11 02:57:00 +02:00
|
|
|
};
|
|
|
|
|
|
|
|
/** An I2C interface
|
|
|
|
*
|
|
|
|
* An I2C interface provides access to an I2C bus, via which I2C
|
|
|
|
* devices may be reached.
|
|
|
|
*/
|
|
|
|
struct i2c_interface {
|
|
|
|
/**
|
|
|
|
* Read data from I2C device
|
|
|
|
*
|
|
|
|
* @v i2c I2C interface
|
|
|
|
* @v i2cdev I2C device
|
|
|
|
* @v offset Starting offset within the device
|
|
|
|
* @v data Data buffer
|
|
|
|
* @v len Length of data buffer
|
|
|
|
* @ret rc Return status code
|
|
|
|
*/
|
|
|
|
int ( * read ) ( struct i2c_interface *i2c, struct i2c_device *i2cdev,
|
|
|
|
unsigned int offset, uint8_t *data,
|
|
|
|
unsigned int len );
|
|
|
|
/**
|
|
|
|
* Write data to I2C device
|
|
|
|
*
|
|
|
|
* @v i2c I2C interface
|
|
|
|
* @v i2cdev I2C device
|
|
|
|
* @v offset Starting offset within the device
|
|
|
|
* @v data Data buffer
|
|
|
|
* @v len Length of data buffer
|
|
|
|
* @ret rc Return status code
|
|
|
|
*/
|
|
|
|
int ( * write ) ( struct i2c_interface *i2c, struct i2c_device *i2cdev,
|
|
|
|
unsigned int offset, const uint8_t *data,
|
|
|
|
unsigned int len );
|
|
|
|
};
|
|
|
|
|
|
|
|
/** A bit-bashing I2C interface
|
|
|
|
*
|
|
|
|
* This provides a standardised way to construct I2C buses via a
|
|
|
|
* bit-bashing interface.
|
|
|
|
*/
|
|
|
|
struct i2c_bit_basher {
|
|
|
|
/** I2C interface */
|
|
|
|
struct i2c_interface i2c;
|
|
|
|
/** Bit-bashing interface */
|
|
|
|
struct bit_basher basher;
|
|
|
|
};
|
|
|
|
|
|
|
|
/** Ten-bit address marker
|
|
|
|
*
|
|
|
|
* This value is ORed with the I2C device address to indicate a
|
|
|
|
* ten-bit address format on the bus.
|
|
|
|
*/
|
|
|
|
#define I2C_TENBIT_ADDRESS 0x7800
|
|
|
|
|
|
|
|
/** An I2C write command */
|
|
|
|
#define I2C_WRITE 0
|
|
|
|
|
|
|
|
/** An I2C read command */
|
|
|
|
#define I2C_READ 1
|
|
|
|
|
|
|
|
/** Bit indices used for I2C bit-bashing interface */
|
|
|
|
enum {
|
2006-06-12 21:29:50 +02:00
|
|
|
/** Serial clock */
|
2006-06-11 02:57:00 +02:00
|
|
|
I2C_BIT_SCL = 0,
|
2006-06-12 21:29:50 +02:00
|
|
|
/** Serial data */
|
2006-06-11 02:57:00 +02:00
|
|
|
I2C_BIT_SDA,
|
|
|
|
};
|
|
|
|
|
|
|
|
/** Delay required for bit-bashing operation */
|
|
|
|
#define I2C_UDELAY 5
|
|
|
|
|
2008-10-01 20:15:07 +02:00
|
|
|
/** Maximum number of cycles to use when attempting a bus reset */
|
|
|
|
#define I2C_RESET_MAX_CYCLES 32
|
|
|
|
|
2006-06-11 02:57:00 +02:00
|
|
|
/**
|
|
|
|
* Check presence of I2C device
|
|
|
|
*
|
|
|
|
* @v i2c I2C interface
|
|
|
|
* @v i2cdev I2C device
|
|
|
|
* @ret rc Return status code
|
|
|
|
*
|
|
|
|
* Checks for the presence of the device on the I2C bus by attempting
|
|
|
|
* a zero-length write.
|
|
|
|
*/
|
|
|
|
static inline int i2c_check_presence ( struct i2c_interface *i2c,
|
|
|
|
struct i2c_device *i2cdev ) {
|
|
|
|
return i2c->write ( i2c, i2cdev, 0, NULL, 0 );
|
|
|
|
}
|
|
|
|
|
2008-10-01 20:15:07 +02:00
|
|
|
extern int init_i2c_bit_basher ( struct i2c_bit_basher *i2cbit,
|
|
|
|
struct bit_basher_operations *bash_op );
|
|
|
|
|
|
|
|
/**
|
|
|
|
* Initialise generic I2C EEPROM device
|
|
|
|
*
|
|
|
|
* @v i2cdev I2C device
|
|
|
|
*/
|
|
|
|
static inline __always_inline void
|
|
|
|
init_i2c_eeprom ( struct i2c_device *i2cdev, unsigned int dev_addr ) {
|
|
|
|
i2cdev->dev_addr = dev_addr;
|
|
|
|
i2cdev->dev_addr_len = 1;
|
|
|
|
i2cdev->word_addr_len = 1;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* Initialise Atmel AT24C11
|
|
|
|
*
|
|
|
|
* @v i2cdev I2C device
|
|
|
|
*/
|
|
|
|
static inline __always_inline void
|
|
|
|
init_at24c11 ( struct i2c_device *i2cdev ) {
|
|
|
|
/* This chip has no device address; it must be the only chip
|
|
|
|
* on the bus. The word address is contained entirely within
|
|
|
|
* the device address field.
|
|
|
|
*/
|
|
|
|
i2cdev->dev_addr = 0;
|
|
|
|
i2cdev->dev_addr_len = 1;
|
|
|
|
i2cdev->word_addr_len = 0;
|
|
|
|
}
|
2006-06-11 02:57:00 +02:00
|
|
|
|
|
|
|
#endif /* _GPXE_I2C_H */
|