List of onboard Peripherals and associated Drivers

32MB Flash

Memory Technology Device (MTD)

• drivers/mtd

8Kbits Serial EEPROM

I2C EEPROMs from most vendors

• drivers/misc/eeprom/at24.c

2 Port 10/100/100 Ethernet Switch

Cavium CNS3xxx Ethernet support

• drivers/net/cns3xxx_eth.c

RTC

Dallas/Maxim? DS1672

• drivers/rtc/rtc-ds1672.c

HWMON

Gateworks System Peripheral

• drivers/hwmon/gsp.c

USB

Cavium CNS3XXX EHCI Module

• drivers/usb/host/ehci-cns3xxx.c
  
• drivers/usb/host/ohci-cns3xxx.c
  

Cavium CNS3XXX OTG Module

• drivers/usb/otg

GPS

• Uses a builtin serial port

GPIO

Emulates a TI 16-bit i2c Digital-IO: ​pca9555:

J9.1 - gpio108
J9.3 - gpio109
J9.5 - gpio110
J9.7 - gpio111
J9.9 - gpio112

Modern kernels use gpiolib to access gpio from userspace. By default these are not exported in the OpenWrt kernels, but you can do so in userspace such as:

echo 108 > /sys/class/gpio/export 
echo 109 > /sys/class/gpio/export 
echo 110 > /sys/class/gpio/export 
echo 111 > /sys/class/gpio/export 
echo 112 > /sys/class/gpio/export 
echo in > /sys/class/gpio/gpio108/direction
echo in > /sys/class/gpio/gpio109/direction
echo in > /sys/class/gpio/gpio110/direction
echo in > /sys/class/gpio/gpio111/direction
echo in > /sys/class/gpio/gpio112/direction

to see the value of an input/output:

cat /sys/class/gpio/gpio112/value

to set the value of an output

echo out > /sys/class/gpio/gpio122/direction  ;# set as output
echo 1 >/sys/class/gpio/gpio112/value ;# set hi
echo 0 >/sys/class/gpio/gpio112/value ;# set low

to see all gpio status (assuming you have debugfs mounted):

cat /sys/kernel/debug/gpio
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