drivers/i2c/nct7802y: Configure remote diodes and local sensor

The patch allows to configure sensors with a remote diode connected
and a on-chip local temperature sensor from the devicetree for the
board that uses this HWM. According to the documentation [1], this is
done by setting the corresponding bits in the Mode Selection Register
(22h). It is necessary for some Intel processors (Apollo Lake SoC)
that do not support PECI and the CPU temperature is taken from the

TEST = After loading the nct7802 module on the Kontron mAL-10 [2] with
       Linux OS, we can see configuration of the HWM with one sensor in
       the thermistor mode:

user@user-apl:~$ sensors
Adapter: ISA adapter
Package id 0:  +41.0°C  (high = +110.0°C, crit = +110.0°C)
Core 0:        +40.0°C  (high = +110.0°C, crit = +110.0°C)
Core 1:        +40.0°C  (high = +110.0°C, crit = +110.0°C)
Core 2:        +41.0°C  (high = +110.0°C, crit = +110.0°C)
Core 3:        +41.0°C  (high = +110.0°C, crit = +110.0°C)

Adapter: SMBus CMI adapter cmi
in0:          +3.35 V  (min =  +0.00 V, max =  +4.09 V)
in1:          +1.92 V
in3:          +1.21 V  (min =  +0.00 V, max =  +2.05 V)
in4:          +1.68 V  (min =  +0.00 V, max =  +2.05 V)
fan1:           0 RPM  (min =    0 RPM)
fan2:         868 RPM  (min =    0 RPM)
fan3:           0 RPM  (min =    0 RPM)
temp1:        +42.5°C  (low  =  +0.0°C, high = +85.0°C)
                       (crit = +100.0°C)  sensor = thermistor
temp4:        +44.0°C  (low  =  +0.0°C, high = +85.0°C)
                       (crit = +100.0°C)
temp6:         +0.0°C

[1] page 30, section 7.2.32, Nuvoton Hardware Monitoring IC NCT7802Y
    with PECI 3.0 interface, datasheet, revision 1.2, february 2012

Change-Id: I28cc4e5cae76cf0bcdad26a50ee6cd43a201d31e
Signed-off-by: Maxim Polyakov <>
Reviewed-by: Werner Zeh <>
Tested-by: build bot (Jenkins) <>
3 files changed
tree: 920a25c9a393444ea132b4279f2d74cc96b350d1
  1. 3rdparty/
  2. configs/
  3. Documentation/
  5. payloads/
  6. src/
  7. tests/
  8. util/
  9. .checkpatch.conf
  10. .clang-format
  11. .editorconfig
  12. .gitignore
  13. .gitmodules
  14. .gitreview
  17. gnat.adc
  19. Makefile

coreboot README

coreboot is a Free Software project aimed at replacing the proprietary BIOS (firmware) found in most computers. coreboot performs a little bit of hardware initialization and then executes additional boot logic, called a payload.

With the separation of hardware initialization and later boot logic, coreboot can scale from specialized applications that run directly firmware, run operating systems in flash, load custom bootloaders, or implement firmware standards, like PC BIOS services or UEFI. This allows for systems to only include the features necessary in the target application, reducing the amount of code and flash space required.

coreboot was formerly known as LinuxBIOS.


After the basic initialization of the hardware has been performed, any desired "payload" can be started by coreboot.

See for a list of supported payloads.

Supported Hardware

coreboot supports a wide range of chipsets, devices, and mainboards.

For details please consult:

Build Requirements

  • make
  • gcc / g++ Because Linux distribution compilers tend to use lots of patches. coreboot does lots of "unusual" things in its build system, some of which break due to those patches, sometimes by gcc aborting, sometimes - and that's worse - by generating broken object code. Two options: use our toolchain (eg. make crosstools-i386) or enable the ANY_TOOLCHAIN Kconfig option if you're feeling lucky (no support in this case).
  • iasl (for targets with ACPI support)
  • pkg-config
  • libssl-dev (openssl)


  • doxygen (for generating/viewing documentation)
  • gdb (for better debugging facilities on some targets)
  • ncurses (for make menuconfig and make nconfig)
  • flex and bison (for regenerating parsers)

Building coreboot

Please consult for details.

Testing coreboot Without Modifying Your Hardware

If you want to test coreboot without any risks before you really decide to use it on your hardware, you can use the QEMU system emulator to run coreboot virtually in QEMU.

Please see for details.

Website and Mailing List

Further details on the project, a FAQ, many HOWTOs, news, development guidelines and more can be found on the coreboot website:

You can contact us directly on the coreboot mailing list:

Copyright and License

The copyright on coreboot is owned by quite a large number of individual developers and companies. Please check the individual source files for details.

coreboot is licensed under the terms of the GNU General Public License (GPL). Some files are licensed under the "GPL (version 2, or any later version)", and some files are licensed under the "GPL, version 2". For some parts, which were derived from other projects, other (GPL-compatible) licenses may apply. Please check the individual source files for details.

This makes the resulting coreboot images licensed under the GPL, version 2.