The Sun V210 and V240 have environmental monitoring devices, as the ALOM is able to view this information. However, the firmware doesn't contain any sensors, which we can see from the boot information (re-ordered to be in ascending address order) or from the firmware tree. Running i2cscan shows more devices (27):

Address Name Compatible OFW Notes
0x0a - - no unknown device
0x0b i2c-bridge SUNW,i2c-imax yes unknown device
0x0c i2c-bridge SUNW,i2c-imax yes unknown device
0x11 - - no unknown device
0x22 gpio i2c-pca9555 yes 16-bit I/O - pin connections not known
0x23 gpio i2c-pca9555 yes 16-bit I/O - pin connections not known
0x25 gpio i2c-pca9555 yes 16-bit I/O - pin connections not known
0x2e - - no unknown device
0x30 - - no unknown device
0x34 gpio i2c-pca9555 yes 16-bit I/O - pin connections not known
0x38 gpio i2c-pca9555 yes 16-bit I/O - pin connections not known
0x44 gpio i2c-pca9555 yes 16-bit I/O - pin connections not known
0x4e - - no unknown device
0x51 motherboard-fru-prom i2c-at24c64 yes 8K EEPROM
0x52 power-supply-fru-prom i2c-at24c64 yes 8K EEPROM
0x54 chassis-fru-prom i2c-at24c64 yes 8K EEPROM
0x57 - - no unknown device
0x58 power-supply-fru-prom i2c-at24c64 yes 8K EEPROM
0x5b dimm-spd i2c-at34c02 yes SPD memory
0x5c dimm-spd i2c-at34c02 yes SPD memory
0x5d dimm-spd i2c-at34c02 yes SPD memory
0x5e dimm-spd i2c-at34c02 yes SPD memory
0x63 dimm-spd i2c-at34c02 yes SPD memory
0x64 dimm-spd i2c-at34c02 yes SPD memory
0x65 dimm-spd i2c-at34c02 yes SPD memory
0x66 dimm-spd i2c-at34c02 yes SPD memory
0x68 rscrtc i2c-ds1307 yes Clock chip
0x69 - - no unknown device

The GPIO's pins are likely to be attached to things like the keyswitch position, system LED's, disk LED's, power supply LED's and status, and the current sensor.

There a 7 fans, 3 temperatures and 9 voltages to monitor, so it's possible that there are one or two hardware monitoring chips present. The most likely seems to be a chips at addresss 0x2e and/or 0x4e, as most sensors have those addresses.

Whilst using i2cscan, I noticed that pcfiic had a bug causing it to return a match on every address with i2cscan's quick write. This turned out to be a simple fix.

Next steps are to attach the GPIO's, attempt to find which pins are connected to which sensors, and attempt to find the other chips that are at the addresses not shown by the firmware - the device at address 0x57 is likely to be an EEPROM of some sort. One possibility is to port OpenBSD's sensor scanning code.


Sun V240 ALOM output

sc> showenvironment


=============== Environmental Status ===============


--------------------------------------------------------------------------------
System Temperatures (Temperatures in Celsius):
--------------------------------------------------------------------------------
Sensor         Status    Temp LowHard LowSoft LowWarn HighWarn HighSoft HighHard
--------------------------------------------------------------------------------
MB.P0.T_CORE    OK         51     --      --      --      84       89       96
MB.P1.T_CORE    OK         43     --      --      --      84       89       96
MB.T_ENC        OK         15     -6      -3       5      40       48       51

--------------------------------------
Front Status Panel:
--------------------------------------
Keyswitch position: NORMAL

--------------------------------------------------------
System Indicator Status:
--------------------------------------------------------
MB.LOCATE            MB.SERVICE           MB.ACT              
--------------------------------------------------------
OFF                  ON                   OFF                 

--------------------------------------------
System Disks:
--------------------------------------------
Disk   Status            Service  OK2RM
--------------------------------------------
HDD0   OK                OFF      OFF
HDD1   NOT PRESENT       OFF      OFF
HDD2   NOT PRESENT       OFF      OFF
HDD3   NOT PRESENT       OFF      OFF

----------------------------------------------------------
Fans (Speeds Revolution Per Minute):
----------------------------------------------------------
Sensor           Status           Speed   Warn    Low
----------------------------------------------------------
F0.RS            OK                5720     --   1000
F1.RS            OK                5720     --   1000
F2.RS            OK                5869     --   1000
MB.P0.F0.RS      OK               16071   2000   2000
MB.P0.F1.RS      OK               16071   2000   2000
MB.P1.F0.RS      OK               17763   2000   2000
MB.P1.F1.RS      OK               16071   2000   2000

--------------------------------------------------------------------------------
Voltage sensors (in Volts):
--------------------------------------------------------------------------------
Sensor         Status       Voltage LowSoft LowWarn HighWarn HighSoft
--------------------------------------------------------------------------------
MB.P0.V_CORE   OK             1.48      --    1.26    1.54       --
MB.P1.V_CORE   OK             1.48      --    1.26    1.54       --
MB.V_VTT       OK             1.24      --    1.17    1.43       --
MB.V_GBE_+2V5  OK             2.50      --    2.25    2.75       --
MB.V_GBE_CORE  OK             1.20      --    1.08    1.32       --
MB.V_VCCTM     OK             2.54      --    2.25    2.75       --
MB.V_+2V5      OK             2.49      --    2.34    2.86       --
MB.V_+1V5      OK             1.51      --    1.35    1.65       --
MB.BAT.V_BAT   OK             2.92      --    2.70      --       --

--------------------------------------------
Power Supply Indicators: 
--------------------------------------------
Supply    Active  Service  OK-to-Remove
--------------------------------------------
PS0       ON      OFF      OFF
PS1       OFF     OFF      OFF

------------------------------------------------------------------------------
Power Supplies:
------------------------------------------------------------------------------
Supply  Status          Underspeed  Overtemp  Overvolt  Undervolt  Overcurrent
------------------------------------------------------------------------------
PS0     OK              OFF         OFF       OFF       OFF        OFF
PS1     No Input Power  OFF         OFF       OFF       OFF        OFF

----------------------
Current sensors: 
----------------------
Sensor          Status
----------------------
MB.FF_SCSI       OK

Sun V240 dmesg output

pcfiic0 at ebus0 addr 320-321 ipl 2e
iic0 at pcfiic0: I2C bus
i2c-bridge at iic0 addr 0x0b not configured
i2c-bridge at iic0 addr 0x0c not configured
gpio at iic0 addr 0x22 not configured
gpio at iic0 addr 0x23 not configured
gpio at iic0 addr 0x25 not configured
seeprom4 at iic0 addr 0x28: nvram: size 8192
gpio at iic0 addr 0x34 not configured
gpio at iic0 addr 0x38 not configured
gpio at iic0 addr 0x44 not configured
seeprom0 at iic0 addr 0x51: motherboard-fru-prom: size 8192
seeprom3 at iic0 addr 0x52: power-supply-fru-prom: size 8192
seeprom1 at iic0 addr 0x54: chassis-fru-prom: size 8192
seeprom2 at iic0 addr 0x58: power-supply-fru-prom: size 8192
spdmem0 at iic0 addr 0x5b
spdmem0: DDR SDRAM (registered), data ECC, 1GB, 333MHz (PC-2700)
spdmem1 at iic0 addr 0x5c
spdmem1: DDR SDRAM (registered), data ECC, 1GB, 333MHz (PC-2700)
spdmem2 at iic0 addr 0x5d
spdmem2: DDR SDRAM (registered), data ECC, 1GB, 333MHz (PC-2700)
spdmem3 at iic0 addr 0x5e
spdmem3: DDR SDRAM (registered), data ECC, 1GB, 333MHz (PC-2700)
spdmem4 at iic0 addr 0x63
spdmem4: DDR SDRAM (registered), data ECC, 1GB, 333MHz (PC-2700)
spdmem5 at iic0 addr 0x64
spdmem5: DDR SDRAM (registered), data ECC, 1GB, 333MHz (PC-2700)
spdmem6 at iic0 addr 0x65
spdmem6: DDR SDRAM (registered), data ECC, 1GB, 333MHz (PC-2700)
spdmem7 at iic0 addr 0x66
spdmem7: DDR SDRAM (registered), data ECC, 1GB, 333MHz (PC-2700)
rscrtc at iic0 addr 0x68 not configured

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