| IIC(9) | Kernel Developer's Manual | IIC(9) | 
iic_acquire_bus,
  iic_release_bus, iic_exec,
  iic_smbus_write_byte,
  iic_smbus_read_byte,
  iic_smbus_receive_byte —
#include <dev/i2c/i2cvar.h>
int
  
  iic_acquire_bus(i2c_tag_t ic,
    int flags);
void
  
  iic_release_bus(i2c_tag_t ic,
    int flags);
int
  
  iic_exec(i2c_tag_t ic,
    i2c_op_t op, i2c_addr_t addr,
    const void *cmdbuf, size_t
    cmdlen, void *buf, size_t
    buflen, int flags);
int
  
  iic_smbus_write_byte(i2c_tag_t
    ic, i2c_addr_t addr, uint8_t
    cmd, uint8_t data, int
    flags);
int
  
  iic_smbus_read_byte(i2c_tag_t
    ic, i2c_addr_t addr, uint8_t
    cmd, uint8_t *datap, int
    flags);
int
  
  iic_smbus_receive_byte(i2c_tag_t
    ic, i2c_addr_t addr, uint8_t
    *datap, int flags);
iic interface
  provides a means of communicating with I2C-connected devices. The System
  Management Bus, or SMBus, is a variant of the I2C bus with a simplified
  command protocol and some electrical differences.
struct i2c_attach_args {
	i2c_tag_t ia_tag;	/* controller */
	i2c_addr_t ia_addr;	/* address of device */
	int ia_size;		/* size (for EEPROMs) */
};
    
    iic_acquire_bus(ic,
    flags)I2C_F_POLL flag
      indicates to iic_acquire_bus() that sleeping is
      not permitted.iic_release_bus(ic,
    flags)I2C_F_POLL flag was passed to
      iic_acquire_bus(), it must also be passed to
      iic_release_bus().iic_exec(ic,
    op, addr,
    cmdbuf, cmdlen,
    buf, buflen,
    flags)iic_exec() initiates the operation by sending a
      START condition on the I2C bus and then transmitting the address of the
      target device along with the transaction type. If
      cmdlen is non-zero, the command pointed to by
      cmdbuf is then sent to the device. If
      buflen is non-zero,
      iic_exec() will then transmit or receive the data,
      as indicated by op. If op
      indicates a read operation, iic_exec() will send a
      REPEATED START before transferring the data. If op
      so indicates, a STOP condition will be sent on the I2C bus at the
      conclusion of the operation. Passing the
      I2C_F_POLL flag indicates to
      iic_exec() that sleeping is not permitted.iic_smbus_write_byte(ic,
    addr, cmd,
    data, flags)iic_smbus_read_byte(ic,
    addr, cmd,
    datap, flags)iic_smbus_receive_byte(ic,
    addr, datap,
    flags)
struct i2c_controller {
	void	*ic_cookie;	/* controller private */
	int	(*ic_acquire_bus)(void *, int);
	void	(*ic_release_bus)(void *, int);
	int	(*ic_exec)(void *, i2c_op_t, i2c_addr_t,
		   const void *, size_t, void *, size_t, int);
	int	(*ic_send_start)(void *, int);
	int	(*ic_send_stop)(void *, int);
	int	(*ic_initiate_xfer)(void *, i2c_addr_t, int);
	int	(*ic_read_byte)(void *, uint8_t *, int);
	int	(*ic_write_byte)(void *, uint8_t, int);
};
The (*ic_acquire_bus)() and
    (*ic_release_bus)() functions must always be
    provided.
The controller driver may elect to provide an
    (*ic_exec)() function. This function is intended for
    use by automated controllers that do not provide manual control over I2C bus
    conditions such as START and STOP.
If the (*ic_exec)() function is not
    provided, the following 5 functions will be used by
    iic_exec() in order to execute the I2C bus
    operation:
(*ic_send_start)(cookie,
    flags)I2C_F_POLL flag indicates that sleeping is not
      permitted.(*ic_send_stop)(cookie,
    flags)I2C_F_POLL flag indicates that sleeping is not
      permitted.(*ic_initiate_xfer)(cookie,
    addr, flags)I2C_F_READ flag indicates a read transfer; the
      lack of this flag indicates a write transfer. The
      I2C_F_POLL flag indicates that sleeping is not
      permitted. The error code ETIMEDOUT should be
      returned if a timeout that would indicate that the device is not present
      occurs.(*ic_read_byte)(cookie,
    datap, flags)I2C_F_LAST flag
      indicates that this is the final byte of the transfer, and that a NACK
      condition should be sent on the I2C bus following the transfer of the
      byte. The I2C_F_STOP flag indicates that a STOP
      condition should be sent on the I2C bus following the transfer of the
      byte. The I2C_F_POLL flag indicates that sleeping
      is not permitted.(*ic_write_byte)(cookie,
    data, flags)I2C_F_STOP flag indicates that a STOP condition
      should be sent on the I2C bus following the transfer of the byte. The
      I2C_F_POLL flag indicates that sleeping is not
      permitted.NXP Semiconductors, I2C-bus Specification and User Manual, Revision 03, http://www.ics.nxp.com/support/documents/i2c/pdf/i2c.bus.specification.pdf, June 19, 2007.
Duracell Inc. et. al., System Management Bus (SMBus) Specification, Version 2.0, http://smbus.org/specs/smbus20.pdf, August 3, 2000.
iic API first appeared in NetBSD
  2.0. OpenBSD support was added in
  OpenBSD 3.6.
iic API was written by Steve C. Woodford and Jason
  R. Thorpe for NetBSD and then ported to
  OpenBSD by Alexander Yurchenko
  <grange@openbsd.org>.
| October 15, 2011 | NetBSD 9.3 |