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33 .Nd SMB generic I/O device driver
39 character device driver provides generic i/o to any
42 In order to control SMB devices, use
44 with the ioctls described below.
45 Any of these ioctl commands takes a pointer to
50 #include <sys/types.h>
73 field is always used, and provides the address of the
74 SMBus slave device to talk to.
75 The slave address is specified in the seven most significant bits
76 .Pq i.e. Dq "left-justified" .
77 The least significant bit of the slave address must be zero.
79 .Bl -column ".Dv SMB_QUICK_WRITE" -compact
80 .It Em Ioctl Ta Em Description
82 .It Dv SMB_QUICK_WRITE Ta
85 command just issues the device address with write intent
86 to the bus, without transferring any data.
87 .It Dv SMB_QUICK_READ Ta
90 command just issues the device address with read intent
91 to the bus, without transferring any data.
95 command sends the byte provided in the
101 command reads a single byte from the device which will
108 command first sends the byte from the
110 field to the device, followed by the byte given in
115 command first sends the byte from the
117 field to the device, followed by the word given in
119 Note that the SMBus byte-order is little-endian by definition.
123 command first sends the byte from the
125 field to the device, and then reads one byte of data from
127 The returned data will be stored in the location pointed to by
132 command first sends the byte from the
134 field to the device, and then reads one word of data from
136 The returned data will be stored in the location pointed to by
141 command first sends the byte from the
143 field to the device, followed by the word provided in
144 .Fa data.process.sdata .
145 It then reads one word of data from the device, and returns it
146 in the location pointed to by
147 .Fa data.process.rdata .
151 command first sends the byte from the
153 field to the device, followed by
155 bytes of data that are taken from the buffer pointed to by
157 The SMBus specification mandates that no more than 32 bytes of
158 data can be transferred in a single block read or write command.
159 This value is available in the constant
160 .Dv SMB_MAXBLOCKSIZE .
164 command first sends the byte from the
166 field to the device, and then reads
168 bytes of data that from the device.
169 These data will be returned in the buffer pointed to by
177 system calls are not implemented by this driver.
181 commands can cause the following driver-specific errors:
184 Device did not respond to selection.
188 Operation not supported by device (not supposed to happen).
190 General argument error.
191 .It Bq Er EWOULDBLOCK
192 SMBus transaction timed out.
200 manual page first appeared in
204 manual page was written by