Lines Matching +full:w1 +full:- +full:gpio

2 Introduction to the 1-wire (w1) subsystem
5 The 1-wire bus is a simple master-slave bus that communicates via a single
11 The w1 subsystem provides the framework for managing w1 masters and
14 All w1 slave devices must be connected to a w1 bus master device.
16 Example w1 master devices:
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
24 What does the w1 subsystem do?
25 ------------------------------
27 When a w1 master driver registers with the w1 subsystem, the following occurs:
29  - sysfs entries for that w1 master are created
30  - the w1 bus is periodically searched for new slave devices
32 When a device is found on the bus, w1 core tries to load the driver for its family
36 in nature, which can contain several (two or one) low-level operations.
44 It is possible that between 1. and 2. w1 master thread will reset bus for searching
49 W1 device families
50 ------------------
52 Slave devices are handled by a driver written for a family of w1 devices.
55 registers with the w1 subsystem.
60   - (ds18?20 thermal sensor family driver)
61     provides temperature reading function which is bound to ->rbin() method
65   - driver for simple 64bit memory cell provides ID reading method.
70 What does a w1 master driver need to implement?
71 -----------------------------------------------
73 The driver for w1 bus master must provide at minimum two functions.
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.
82 See struct w1_bus_master definition in w1.h for details.
85 w1 master sysfs interface
86 -------------------------
89 <xx-xxxxxxxxxxxx>         A directory for a found device. The format is
90                           family-serial
91 bus                       (standard) symlink to the w1 bus
92 driver                    (standard) symlink to the w1 driver
100                           -1=continual (default)
107 If you have a w1 bus that never changes (you don't add or remove devices),
118 w1_master_search remains greater than 0 or is -1.  Each search attempt
122 w1 slave sysfs interface
123 ------------------------
126 bus                 (standard) symlink to the w1 bus
127 driver              (standard) symlink to the w1 driver