1-Wire Driver - Raspberry Pi Hardware Reference - page 164

Table 11-1. 1-Wire Slave Driver Support

Device Module Description

DS18S20 w1_therm.c Precision digital thermometer

DS18B20 Programmable resolution thermometer

DS1822 Econo digital thermometer

DS28EA00 9- to 12-bit digital thermometer with PIO

bq27000 w1_bq27000.c Highly accurate battery monitor

DS2408 w1_ds2408.c Eight-channel addressable switch

DS2423 w1_ds2423.c 4 KB RAM with counter

DS2431 w1_ds2431.c 1 KB EEPROM

DS2433 w1_ds2433.c 4 KB EEPROM

DS2760 w1_ds2760.c Precision Li+ battery monitor

DS2780 w1_ds2780.c Stand-alone fuel gauge

Reading Temperature
The support for the usual temperature sensors is found in the kernel module w1_therm .
When you first boot your Raspbian Linux, that module may not be loaded. You can check
for it with the lsmod command:

$ lsmod
Module Size Used by
snd_bcm2835 12808 1
snd_pcm 74834 1 snd_bcm2835
snd_seq 52536 0
snd_timer 19698 2 snd_seq, snd_pcm
snd_seq_device 6300 1 snd_seq
snd 52489 7 snd_seq_device , snd_timer ,
snd_seq , snd_pcm, snd_bcm2835
snd_page_alloc 4951 1 snd_pcm

The module w1_therm is not loaded according to the example. This module also
depends on the driver module wire . Another thing you can check is the pseudo file
system:

$ ls -l /sys/bus/w1
ls: cannot access /sys/bus/w1 : No such file or directory