Documentation/w1/w1-generic.rst

2 Introduction to the 1-wire (w1) subsystem
5 The 1-wire bus is a simple master-slave bus that communicates via a single
6 signal wire (plus ground, so two wires).
9 drain output and by sampling the logic level of the signal line.
18     - DS9490 usb device
19     - W1-over-GPIO
20     - DS2482 (i2c to w1 bridge)
21     - Emulated devices, such as a RS232 converter, parallel port adapter, etc
25 ------------------------------
29  - sysfs entries for that w1 master are created
30  - the w1 bus is periodically searched for new slave devices
35 almost any kind of operations. Each logical operation is a transaction
36 in nature, which can contain several (two or one) low-level operations.
50 ------------------
52 Slave devices are handled by a driver written for a family of w1 devices.
60   - (ds18?20 thermal sensor family driver)
61     provides temperature reading function which is bound to ->rbin() method
62     of the above w1_family_ops structure.
65   - driver for simple 64bit memory cell provides ID reading method.
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78 Devices that support the 1-wire natively must provide the ability to write and
81 Most hardware provides higher-level functions that offload w1 handling.
86 -------------------------
89 <xx-xxxxxxxxxxxx>         A directory for a found device. The format is
90                           family-serial
94 w1_master_attempts        (ro) the number of times a search was attempted
95 w1_master_max_slave_count (rw) maximum number of slaves to search for at a time
96 w1_master_name            (ro) the name of the device (w1_bus_masterX)
99 w1_master_search          (rw) the number of searches left to do,
100                           -1=continual (default)
101 w1_master_slave_count     (ro) the number of slaves found
102 w1_master_slaves          (ro) the names of the slaves, one per line
108 you can set the module parameter search_count to a small positive number
109 for an initially small number of bus searches.  Alternatively it could be
116 Bus searches occur at an interval, specified as a sum of timeout and
117 timeout_us module parameters (either of which may be 0) for as long as
118 w1_master_search remains greater than 0 or is -1.  Each search attempt
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