Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  1) Kernel driver pc87427
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  2) =====================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  3) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  4) Supported chips:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  5) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  6)   * National Semiconductor PC87427
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  7) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  8)     Prefix: 'pc87427'
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  9) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10)     Addresses scanned: none, address read from Super I/O config space
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12)     Datasheet: No longer available
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) Author: Jean Delvare <jdelvare@suse.de>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) Thanks to Amir Habibi at Candelis for setting up a test system, and to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) Michael Kress for testing several iterations of this driver.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) Description
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) -----------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) The National Semiconductor Super I/O chip includes complete hardware
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) monitoring capabilities. It can monitor up to 18 voltages, 8 fans and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) 6 temperature sensors. Only the fans and temperatures are supported at
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) the moment, voltages aren't.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) This chip also has fan controlling features (up to 4 PWM outputs),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) which are partly supported by this driver.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) The driver assumes that no more than one chip is present, which seems
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) reasonable.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) Fan Monitoring
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) --------------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) Fan rotation speeds are reported as 14-bit values from a gated clock
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) signal. Speeds down to 83 RPM can be measured.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) An alarm is triggered if the rotation speed drops below a programmable
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) limit. Another alarm is triggered if the speed is too low to be measured
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) (including stalled or missing fan).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) Fan Speed Control
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) -----------------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) Fan speed can be controlled by PWM outputs. There are 4 possible modes:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) always off, always on, manual and automatic. The latter isn't supported
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) by the driver: you can only return to that mode if it was the original
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) setting, and the configuration interface is missing.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) Temperature Monitoring
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) ----------------------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) The PC87427 relies on external sensors (following the SensorPath
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) standard), so the resolution and range depend on the type of sensor
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) connected. The integer part can be 8-bit or 9-bit, and can be signed or
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) not. I couldn't find a way to figure out the external sensor data
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) temperature format, so user-space adjustment (typically by a factor 2)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) may be required.