[coreboot-gerrit] Change in coreboot[master]: asus/f2a85-m: Enable automatic fan control

[Tobias Diedrich (Code Review)]

Tobias Diedrich has uploaded a new patch set (#2). ( https://review.coreboot.org/19293 )

Change subject: asus/f2a85-m: Enable automatic fan control
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asus/f2a85-m: Enable automatic fan control

This adds fancontrol registers for the IT8728F and enables automatic
fancontrol for the F2A85-M and F2A85-M LE with the ASUS 'normal'
register settings.

Only the main CPU fan can be speed controlled on this board.

The three asus presets only differ in the start and full speed
temperatures (in degrees celsius):
normal: start @20, full @70
silent: start @30, full @70
turbo:  start @10, full @60

Before this change the fan speed is stuck at a default value of 50%
PWM duty cycle.

In particular the following fan control registers are involved:

reg 0x0b (0x40, default 0x00)
Fan PWM Smoothing Step Frequency Selection Register
bits 7-6 control sampling rate, this changes the sampling rate from 1Hz (Default) to 16Hz (ASUS).

reg 0x15 (0x80, default 0x00)
FAN_CTL1 PWM Control Register
bit7 enables automatic control

reg 0x60 (0x80, default 0x7f)
FAN_CTL1 SmartGuardian Automatic Mode Temperature Limit of OFF Register
With the default value of 0x7f the fan is never turned on in auto mode, with 0x80 (-128) it is never turned off.

reg 0x61 (0x14, default 0x7f)
FAN_CTL1 SmartGuardian Automatic Mode Temperature Limit of Fan Start Register
Minimum PWM reached at 20 degrees (vs default of 127 degrees)

reg 0x62 (0x46, default 0x7f)
FAN_CTL1 SmartGuardian Automatic Mode Temperature Limit of Full Speed Register
100% threshold at 70 degress (vs default of 127 degrees)

reg 0x64 (0xa0, default 0x00)
FAN_CTL1 SmartGuardian Automatic Mode Control Register
bit7 enables data smoothing
bit6-0 set the slope of the control curve (32)

reg 0x65 (0x40, default 0x00)
FAN_CTL1 SmartGuardian Automatic Mode △-Temperature Registers
bit6 enable full duty cycle if any thermal limit is reached

Change-Id: Idf0c8908ba5ad6ff552b8302bffc638aa9052941
Signed-off-by: Tobias Diedrich <ranma+coreboot at tdiedrich.de>
---
M src/mainboard/asus/f2a85-m/devicetree_f2a85-m.cb
M src/mainboard/asus/f2a85-m/devicetree_f2a85-m_le.cb
M src/superio/ite/it8728f/chip.h
M src/superio/ite/it8728f/it8728f_hwm.c
4 files changed, 86 insertions(+), 4 deletions(-)


  git pull ssh://review.coreboot.org:29418/coreboot refs/changes/93/19293/2
-- 
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Gerrit-MessageType: newpatchset
Gerrit-Change-Id: Idf0c8908ba5ad6ff552b8302bffc638aa9052941
Gerrit-PatchSet: 2
Gerrit-Project: coreboot
Gerrit-Branch: master
Gerrit-Owner: Tobias Diedrich <ranma+coreboot at tdiedrich.de>