'\" t
.\"     Title: struct i2c_adapter_quirks
.\"    Author: [FIXME: author] [see http://docbook.sf.net/el/author]
.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
.\"      Date: January 2017
.\"    Manual: I2C and SMBus Subsystem
.\"    Source: Kernel Hackers Manual 4.8.15
.\"  Language: English
.\"
.TH "STRUCT I2C_ADAPTER_Q" "9" "January 2017" "Kernel Hackers Manual 4\&.8\&." "I2C and SMBus Subsystem"
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.SH "NAME"
struct_i2c_adapter_quirks \- describe flaws of an i2c adapter
.SH "SYNOPSIS"
.sp
.nf
struct i2c_adapter_quirks {
  u64 flags;
  int max_num_msgs;
  u16 max_write_len;
  u16 max_read_len;
  u16 max_comb_1st_msg_len;
  u16 max_comb_2nd_msg_len;
};  
.fi
.SH "MEMBERS"
.PP
flags
.RS 4
see I2C_AQ_* for possible flags and read below
.RE
.PP
max_num_msgs
.RS 4
maximum number of messages per transfer
.RE
.PP
max_write_len
.RS 4
maximum length of a write message
.RE
.PP
max_read_len
.RS 4
maximum length of a read message
.RE
.PP
max_comb_1st_msg_len
.RS 4
maximum length of the first msg in a combined message
.RE
.PP
max_comb_2nd_msg_len
.RS 4
maximum length of the second msg in a combined message
.RE
.SH "DESCRIPTION"
.PP
Note about combined messages: Some I2C controllers can only send one message per transfer, plus something called combined message or write\-then\-read\&. This is (usually) a small write message followed by a read message and barely enough to access register based devices like EEPROMs\&. There is a flag to support this mode\&. It implies max_num_msg = 2 and does the length checks with max_comb_*_len because combined message mode usually has its own limitations\&. Because of HW implementations, some controllers can actually do write\-then\-anything or other variants\&. To support that, write\-then\-read has been broken out into smaller bits like write\-first and read\-second which can be combined as needed\&.
.SH "COPYRIGHT"
.br