diff options
Diffstat (limited to 'Documentation/w1/slaves')
| -rw-r--r-- | Documentation/w1/slaves/00-INDEX | 2 | ||||
| -rw-r--r-- | Documentation/w1/slaves/w1_ds28e04 | 36 | ||||
| -rw-r--r-- | Documentation/w1/slaves/w1_therm | 15 |
3 files changed, 50 insertions, 3 deletions
diff --git a/Documentation/w1/slaves/00-INDEX b/Documentation/w1/slaves/00-INDEX index 75613c9ac4d..6e18c70c347 100644 --- a/Documentation/w1/slaves/00-INDEX +++ b/Documentation/w1/slaves/00-INDEX @@ -4,3 +4,5 @@ w1_therm - The Maxim/Dallas Semiconductor ds18*20 temperature sensor. w1_ds2423 - The Maxim/Dallas Semiconductor ds2423 counter device. +w1_ds28e04 + - The Maxim/Dallas Semiconductor ds28e04 eeprom. diff --git a/Documentation/w1/slaves/w1_ds28e04 b/Documentation/w1/slaves/w1_ds28e04 new file mode 100644 index 00000000000..7819b65cfa4 --- /dev/null +++ b/Documentation/w1/slaves/w1_ds28e04 @@ -0,0 +1,36 @@ +Kernel driver w1_ds28e04 +======================== + +Supported chips: + * Maxim DS28E04-100 4096-Bit Addressable 1-Wire EEPROM with PIO + +supported family codes: + W1_FAMILY_DS28E04 0x1C + +Author: Markus Franke, <franke.m@sebakmt.com> <franm@hrz.tu-chemnitz.de> + +Description +----------- + +Support is provided through the sysfs files "eeprom" and "pio". CRC checking +during memory accesses can optionally be enabled/disabled via the device +attribute "crccheck". The strong pull-up can optionally be enabled/disabled +via the module parameter "w1_strong_pullup". + +Memory Access + + A read operation on the "eeprom" file reads the given amount of bytes + from the EEPROM of the DS28E04. + + A write operation on the "eeprom" file writes the given byte sequence + to the EEPROM of the DS28E04. If CRC checking mode is enabled only + fully aligned blocks of 32 bytes with valid CRC16 values (in bytes 30 + and 31) are allowed to be written. + +PIO Access + + The 2 PIOs of the DS28E04-100 are accessible via the "pio" sysfs file. + + The current status of the PIO's is returned as an 8 bit value. Bit 0/1 + represent the state of PIO_0/PIO_1. Bits 2..7 do not care. The PIO's are + driven low-active, i.e. the driver delivers/expects low-active values. diff --git a/Documentation/w1/slaves/w1_therm b/Documentation/w1/slaves/w1_therm index 0403aaaba87..cc62a95e477 100644 --- a/Documentation/w1/slaves/w1_therm +++ b/Documentation/w1/slaves/w1_therm @@ -3,6 +3,7 @@ Kernel driver w1_therm Supported chips: * Maxim ds18*20 based temperature sensors. + * Maxim ds1825 based temperature sensors. Author: Evgeniy Polyakov <johnpol@2ka.mipt.ru> @@ -15,6 +16,7 @@ supported family codes: W1_THERM_DS18S20 0x10 W1_THERM_DS1822 0x22 W1_THERM_DS18B20 0x28 +W1_THERM_DS1825 0x3B Support is provided through the sysfs w1_slave file. Each open and read sequence will initiate a temperature conversion then provide two @@ -32,9 +34,16 @@ currently supported. The driver also doesn't support reduced precision (which would also reduce the conversion time). The module parameter strong_pullup can be set to 0 to disable the -strong pullup or 1 to enable. If enabled the 5V strong pullup will be -enabled when the conversion is taking place provided the master driver -must support the strong pullup (or it falls back to a pullup +strong pullup, 1 to enable autodetection or 2 to force strong pullup. +In case of autodetection, the driver will use the "READ POWER SUPPLY" +command to check if there are pariste powered devices on the bus. +If so, it will activate the master's strong pullup. +In case the detection of parasite devices using this command fails +(seems to be the case with some DS18S20) the strong pullup can +be force-enabled. +If the strong pullup is enabled, the master's strong pullup will be +driven when the conversion is taking place, provided the master driver +does support the strong pullup (or it falls back to a pullup 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 |