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SMB(4)		       FreeBSD Kernel Interfaces Manual			SMB(4)

NAME
     smb -- SMB	generic	I/O device driver

SYNOPSIS
     device smb

DESCRIPTION
     The smb character device driver provides generic i/o to any smbus(4)
     instance.	In order to control SMB	devices, use /dev/smb? with the	ioctls
     described below.  Any of these ioctl commands takes a pointer to struct
     smbcmd as its argument.

     #include <sys/types.h>

     struct smbcmd {
	     char cmd;
	     int count;
	     u_char slave;
	     union {
		     char byte;
		     short word;

		     char *byte_ptr;
		     short *word_ptr;

		     struct {
			     short sdata;
			     short *rdata;
		     } process;
	     } data;
     };

     The slave field is	always used, and provides the address of the SMBus
     slave device to talk to.  The slave address is specified in the seven
     most significant bits (i.e. ``left-justified'').  The least significant
     bit of the	slave address must be zero.

     Ioctl		Description

     SMB_QUICK_WRITE	The QuickWrite command just issues the device address
			with write intent to the bus, without transferring any
			data.
     SMB_QUICK_READ	The QuickRead command just issues the device address
			with read intent to the	bus, without transferring any
			data.
     SMB_SENDB		The SendByte command sends the byte provided in	the
			cmd field to the device.
     SMB_RECVB		The ReceiveByte	command	reads a	single byte from the
			device which will be returned in the cmd field.
     SMB_WRITEB		The WriteByte command first sends the byte from	the
			cmd field to the device, followed by the byte given in
			data.byte.
     SMB_WRITEW		The WriteWord command first sends the byte from	the
			cmd field to the device, followed by the word given in
			data.word.  Note that the SMBus	byte-order is little-
			endian by definition.
     SMB_READB		The ReadByte command first sends the byte from the cmd
			field to the device, and then reads one	byte of	data
			from the device.  The returned data will be stored in
			the location pointed to	by data.byte_ptr.
     SMB_READW		The ReadWord command first sends the byte from the cmd
			field to the device, and then reads one	word of	data
			from the device.  The returned data will be stored in
			the location pointed to	by data.word_ptr.
     SMB_PCALL		The ProcedureCall command first	sends the byte from
			the cmd	field to the device, followed by the word pro-
			vided in data.process.sdata.  It then reads one	word
			of data	from the device, and returns it	in the loca-
			tion pointed to	by data.process.rdata.
     SMB_BWRITE		The BlockWrite command first sends the byte from the
			cmd field to the device, followed by count bytes of
			data that are taken from the buffer pointed to by
			data.byte_ptr.	The SMBus specification	mandates that
			no more	than 32	bytes of data can be transferred in a
			single block read or write command.  This value	is
			available in the constant SMB_MAXBLOCKSIZE.
     SMB_BREAD		The BlockRead command first sends the byte from	the
			cmd field to the device, and then reads	count bytes of
			data that from the device.  These data will be
			returned in the	buffer pointed to by data.byte_ptr.

     The read(2) and write(2) system calls are not implemented by this driver.

ERRORS
     The ioctl(2) commands can cause the following driver-specific errors:

     [ENXIO]		Device did not respond to selection.

     [EBUSY]		Device still in	use.

     [ENODEV]		Operation not supported	by device (not supposed	to
			happen).

     [EINVAL]		General	argument error.

     [EWOULDBLOCK]	SMBus transaction timed	out.

SEE ALSO
     ioctl(2), smbus(4)

HISTORY
     The smb manual page first appeared	in FreeBSD 3.0.

AUTHORS
     This manual page was written by Nicolas Souchu.

FreeBSD	10.1		       February	6, 2009			  FreeBSD 10.1

NAME | SYNOPSIS | DESCRIPTION | ERRORS | SEE ALSO | HISTORY | AUTHORS

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=smb&sektion=4&manpath=FreeBSD+10.1-RELEASE>

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