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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 provided in data.process.sdata.  It then
                            reads one word of data from the device, and
                            returns it in the location 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 11.0-PRERELEASE        February 6, 2009        FreeBSD 11.0-PRERELEASE

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&manpath=FreeBSD+10.3-RELEASE+and+Ports>

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