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C

#ifndef _LINUX_ETRAXI2C_H
#define _LINUX_ETRAXI2C_H
/* etraxi2c _IOC_TYPE, bits 8 to 15 in ioctl cmd */
#define ETRAXI2C_IOCTYPE 44
/* supported ioctl _IOC_NR's */
/* in write operations, the argument contains both i2c
* slave, register and value.
*/
#define I2C_WRITEARG(slave, reg, value) (((slave) << 16) | ((reg) << 8) | (value))
#define I2C_READARG(slave, reg) (((slave) << 16) | ((reg) << 8))
#define I2C_ARGSLAVE(arg) ((arg) >> 16)
#define I2C_ARGREG(arg) (((arg) >> 8) & 0xff)
#define I2C_ARGVALUE(arg) ((arg) & 0xff)
#define I2C_WRITEREG 0x1 /* write to an I2C register */
#define I2C_READREG 0x2 /* read from an I2C register */
/*
EXAMPLE usage:
i2c_arg = I2C_WRITEARG(STA013_WRITE_ADDR, reg, val);
ioctl(fd, _IO(ETRAXI2C_IOCTYPE, I2C_WRITEREG), i2c_arg);
i2c_arg = I2C_READARG(STA013_READ_ADDR, reg);
val = ioctl(fd, _IO(ETRAXI2C_IOCTYPE, I2C_READREG), i2c_arg);
*/
/* Extended part */
#define I2C_READ 0x4 /* reads from I2C device */
#define I2C_WRITE 0x3 /* writes to I2C device */
#define I2C_WRITEREAD 0x5 /* writes to I2C device where to start reading */
typedef struct _I2C_DATA
{
unsigned char slave; /* I2C address (8-bit representation) of slave device */
unsigned char wbuf[256]; /* Write buffer (length = 256 bytes) */
unsigned int wlen; /* Number of bytes to write from wbuf[] */
unsigned char rbuf[256]; /* Read buffer (length = 256 bytes) */
unsigned int rlen; /* Number of bytes to read into rbuf[] */
} I2C_DATA;
#endif