STRUCT W1_BUS_MASTER(9)           W1 API internal to the kernel           STRUCT W1_BUS_MASTER(9)



NAME
       struct_w1_bus_master - operations available on a bus master

SYNOPSIS
       struct w1_bus_master {
         void * data;
         u8 (* read_bit) (void *);
         void (* write_bit) (void *, u8);
         u8 (* touch_bit) (void *, u8);
         u8 (* read_byte) (void *);
         void (* write_byte) (void *, u8);
         u8 (* read_block) (void *, u8 *, int);
         void (* write_block) (void *, const u8 *, int);
         u8 (* triplet) (void *, u8);
         u8 (* reset_bus) (void *);
         u8 (* set_pullup) (void *, int);
         void (* search) (void *, struct w1_master *,u8, w1_slave_found_callback);
       };

MEMBERS
       data
           the first parameter in all the functions below

       read_bit
           Sample the line level return the level read (0 or 1)

       write_bit
           Sets the line level

       touch_bit
           the lowest-level function for devices that really support the 1-wire protocol.
           touch_bit(0) = write-0 cycle touch_bit(1) = write-1 / read cycle return the bit read
           (0 or 1)

       read_byte
           Reads a bytes. Same as 8 touch_bit(1) calls.  return the byte read

       write_byte
           Writes a byte. Same as 8 touch_bit(x) calls.

       read_block
           Same as a series of read_byte calls return the number of bytes read

       write_block
           Same as a series of write_byte calls

       triplet
           Combines two reads and a smart write for ROM searches return bit0=Id bit1=comp_id
           bit2=dir_taken

       reset_bus
           long write-0 with a read for the presence pulse detection return -1=Error, 0=Device
           present, 1=No device present

       set_pullup
           Put out a strong pull-up pulse of the specified duration.  return -1=Error,
           0=completed

       search
           Really nice hardware can handles the different types of ROM search w1_master* is
           passed to the slave found callback. u8 is search_type, W1_SEARCH or W1_ALARM_SEARCH

NOTE
       read_bit and write_bit are very low level functions and should only be used with hardware
       that doesn't really support 1-wire operations, like a parallel/serial port. Either define
       read_bit and write_bit OR define, at minimum, touch_bit and reset_bus.

AUTHOR
       David Fries <David AT Fries.net>
           Author.

COPYRIGHT
Kernel Hackers Manual 4.8.                 January 2017                   STRUCT W1_BUS_MASTER(9)