diff options
Diffstat (limited to 'Documentation/w1')
| -rw-r--r-- | Documentation/w1/slaves/w1_therm | 11 | ||||
| -rw-r--r-- | Documentation/w1/w1.generic | 30 |
2 files changed, 29 insertions, 12 deletions
diff --git a/Documentation/w1/slaves/w1_therm b/Documentation/w1/slaves/w1_therm index cc62a95e4..13411fe52 100644 --- a/Documentation/w1/slaves/w1_therm +++ b/Documentation/w1/slaves/w1_therm @@ -11,12 +11,14 @@ Author: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Description ----------- -w1_therm provides basic temperature conversion for ds18*20 devices. +w1_therm provides basic temperature conversion for ds18*20 devices, and the +ds28ea00 device. supported family codes: W1_THERM_DS18S20 0x10 W1_THERM_DS1822 0x22 W1_THERM_DS18B20 0x28 W1_THERM_DS1825 0x3B +W1_THERM_DS28EA00 0x42 Support is provided through the sysfs w1_slave file. Each open and read sequence will initiate a temperature conversion then provide two @@ -48,3 +50,10 @@ resistor). The DS18b20 temperature sensor specification lists a maximum current draw of 1.5mA and that a 5k pullup resistor is not sufficient. The strong pullup is designed to provide the additional current required. + +The DS28EA00 provides an additional two pins for implementing a sequence +detection algorithm. This feature allows you to determine the physical +location of the chip in the 1-wire bus without needing pre-existing +knowledge of the bus ordering. Support is provided through the sysfs +w1_seq file. The file will contain a single line with an integer value +representing the device index in the bus starting at 0. diff --git a/Documentation/w1/w1.generic b/Documentation/w1/w1.generic index b2033c64c..b3ffaf8cf 100644 --- a/Documentation/w1/w1.generic +++ b/Documentation/w1/w1.generic @@ -76,21 +76,24 @@ See struct w1_bus_master definition in w1.h for details. w1 master sysfs interface ------------------------------------------------------------------ -<xx-xxxxxxxxxxxxx> - a directory for a found device. The format is family-serial +<xx-xxxxxxxxxxxxx> - A directory for a found device. The format is family-serial bus - (standard) symlink to the w1 bus driver - (standard) symlink to the w1 driver -w1_master_add - Manually register a slave device -w1_master_attempts - the number of times a search was attempted +w1_master_add - (rw) manually register a slave device +w1_master_attempts - (ro) the number of times a search was attempted w1_master_max_slave_count - - maximum number of slaves to search for at a time -w1_master_name - the name of the device (w1_bus_masterX) -w1_master_pullup - 5V strong pullup 0 enabled, 1 disabled -w1_master_remove - Manually remove a slave device -w1_master_search - the number of searches left to do, -1=continual (default) + - (rw) maximum number of slaves to search for at a time +w1_master_name - (ro) the name of the device (w1_bus_masterX) +w1_master_pullup - (rw) 5V strong pullup 0 enabled, 1 disabled +w1_master_remove - (rw) manually remove a slave device +w1_master_search - (rw) the number of searches left to do, + -1=continual (default) w1_master_slave_count - - the number of slaves found -w1_master_slaves - the names of the slaves, one per line -w1_master_timeout - the delay in seconds between searches + - (ro) the number of slaves found +w1_master_slaves - (ro) the names of the slaves, one per line +w1_master_timeout - (ro) the delay in seconds between searches +w1_master_timeout_us + - (ro) the delay in microseconds beetwen searches If you have a w1 bus that never changes (you don't add or remove devices), you can set the module parameter search_count to a small positive number @@ -101,6 +104,11 @@ generally only make sense when searching is disabled, as a search will redetect manually removed devices that are present and timeout manually added devices that aren't on the bus. +Bus searches occur at an interval, specified as a summ of timeout and +timeout_us module parameters (either of which may be 0) for as long as +w1_master_search remains greater than 0 or is -1. Each search attempt +decrements w1_master_search by 1 (down to 0) and increments +w1_master_attempts by 1. w1 slave sysfs interface ------------------------------------------------------------------ |