Some stuff from playing with the stupidly named CHIP .
There is a script shipped with the CHIP images that will dump some information from the battery controller. Which is sort of useful I guess.
[chip@chip] $ sudo battery.sh BAT_STATUS=0 CHARG_IND=1 BAT_EXIST=1 CHARGE_CTL=0xc9 CHARGE_CTL2=0x45 Battery voltage = 3930.3mV Battery discharge current = 0mA Battery charge current = 882.5mA Internal temperature = 51.9c
There are two leds on board, a pink one that is directly wired into power and a
status led connected over i2c. The led can be control directly over i2c with
[chip@chip] $ sudo i2cset -f -y 0 0x34 0x93 0x0 #turn off [chip@chip] $ sudo i2cset -f -y 0 0x34 0x93 0x1 #turn on
On my CHIP image the led is showing some sort of heartbeat that isn't stopped
when I manually intervene. On their forums the
method is reccomended
to control the led, but the heartbeat made this impossible.
After a ton of poking and searching, trying to see if you can get
log processes that access a path (doesn't look like you can) I came across
ledtrig-cpu in the dmesg
[ 2.315000] ledtrig-cpu: registered to indicate activity on CPUs
is a kernel module for showing event status on built in leds,
some inscruitable BBB
documentation that somewhat shows how to
there is an entry for each on the leds on board, listed with
their colour. We can have a play with the led by looking at the following:
[root@chip] # cd /sys/class/leds/chip:white:status [root@chip] # ls brightness device max_brightness power subsystem trigger uevent [root@chip] # cat brightness 0 [root@chip] # cat max_brightness 255 [root@chip] # echo 24 > brightness [root@chip] # echo 10 > brightness [root@chip] # echo 255 > brightness [root@chip] # echo 0 > brightness
Changing the value in
didn't dim the STAT led at all, I can only
set it on or off.
[root@chip] # cat trigger [none] kbd-scrollock kbd-numlock kbd-capslock kbd-kanalock kbd-shiftlock kbd-altgrlock kbd-ctrllock kbd-altlock kbd-shiftllock kbd-shiftrlock kbd-ctrlllock kbd-ctrlrlock nand-disk usb-gadget usb-host axp20x-usb-online timer oneshot heartbeat backlight gpio cpu0 default-on transient flash torch mmc0 rfkill0 rfkill1 rfkill2 rfkill3
The trigger functionality was much more fun. Trigger modes can be changed by writing their name to the file
[root@chip] # echo backlight > trigger [root@chip] # echo transient > trigger [root@chip] # echo torch > trigger [root@chip] # echo mmc0 > trigger [root@chip] # echo timer > trigger
Setting the trigger mode to
added two more files the
[root@chip] # ls brightness delay_off delay_on device max_brightness power subsystem trigger uevent [root@chip] # cat delay_on 500 [root@chip] # cat delay_off 500 [root@chip] # echo 2000 > delay_off
We can restore the trigger to the
[root@chip] # echo heartbeat > trigger
Reading: Babylon's Ashes, Diamond Age