diff options
Diffstat (limited to 'Documentation/w1')
| -rw-r--r-- | Documentation/w1/w1.generic | 18 |
1 files changed, 15 insertions, 3 deletions
diff --git a/Documentation/w1/w1.generic b/Documentation/w1/w1.generic index f937fbe1cacb..4c6509dd4789 100644 --- a/Documentation/w1/w1.generic +++ b/Documentation/w1/w1.generic @@ -27,8 +27,19 @@ When a w1 master driver registers with the w1 subsystem, the following occurs: When a device is found on the bus, w1 core checks if driver for it's family is loaded. If so, the family driver is attached to the slave. -If there is no driver for the family, a simple sysfs entry is created -for the slave device. +If there is no driver for the family, default one is assigned, which allows to perform +almost any kind of operations. Each logical operation is a transaction +in nature, which can contain several (two or one) low-level operations. +Let's see how one can read EEPROM context: +1. one must write control buffer, i.e. buffer containing command byte +and two byte address. At this step bus is reset and appropriate device +is selected using either W1_SKIP_ROM or W1_MATCH_ROM command. +Then provided control buffer is being written to the wire. +2. reading. This will issue reading eeprom response. + +It is possible that between 1. and 2. w1 master thread will reset bus for searching +and slave device will be even removed, but in this case 0xff will +be read, since no device was selected. W1 device families @@ -89,4 +100,5 @@ driver - (standard) symlink to the w1 driver name - the device name, usually the same as the directory name w1_slave - (optional) a binary file whose meaning depends on the family driver - +rw - (optional) created for slave devices which do not have + appropriate family driver. Allows to read/write binary data. |