[PATCH 0/2] hwmon: (asus_rog_ryujin) Ryujin III pump control source

[Zac Lanzon <lanzonza@gmail.com>]

The RYUJIN III pump either runs at the duty set over USB or is handed
to its internal controller, which follows the PWM of the motherboard
header its 4-pin cable is plugged into. Byte 2 of the set cooler duty
command selects which. The driver sends 1 there with every duty write,
so a pwm2 write takes the pump away from its internal controller, and
after power-on a pwm1 write of the reported 40% leaves the pump at full
speed. Patch 1 fixes both. Patch 2 adds pwm1_enable to switch between
the two and to report which one is in control.

Patch 1 fixes a user-visible bug and applies to v7.3-rc4 as well as to
hwmon-next. On v7.3-rc4 the driver does not bind the base RYUJIN III
360, whose ID is only in hwmon-next, so there patch 1 changes behavior
for the EXTREME, EVA and WHITE EDITION, none of which I could test.
Edward Blair's analysis of the WHITE EDITION firmware shows the same
pump control source. Patch 2 is a new feature for hwmon-next.

Tested on a RYUJIN III 360, firmware AURJ2-S750-0108, with out-of-tree
builds of drivers/hwmon/asus_rog_ryujin.c on 7.0.0-34-generic:
hwmon-next 9edd5ab2656 as is, with patch 1, and with both patches. The
pump cable is on AIO_PUMP (nct6799 pwm7, set by hand for the tests); it
was on CPU_FAN at the time of the first comments in the linked issue.
Pump rpm at header 50% / 80%, then the reported source:

                                  before       patch 1      patches 1-2
a  on header, pwm2 = 40%          1710/1710 1  2100/3060 0  2145/3090 0
b  on header, pwm1 = 40%          1725/1740 1  1740/1740 1  1740/1740 1
c  pwm1 = 60%, then 40%           2460, 1740   2460, 1740   2475, 1740
d  then pwm2 = 40%                1740/1740 1  1740/1740 1  1740/1740 1
e1 reload with the pump on USB    1740/1740 1  1740/1740 1  1740/1740 1
   then pwm2, pwm1 = 40%          1740, 1740   1755, 1740   1740, 1755
e2 reload with the pump on header 2160/3090 0  2160/3090 0  2160/3105 0
   then pwm2 = 40%                1740/1740 1  2130/3090 0  2130/3090 0
   then pwm1 = 60%                2475 1       2460 1       2475 1
f  pwm1_enable = 2                                          2130/3090 0
   pwm1_enable = 1                                          1740/1740 1
   pwm1_enable = 0, 3                                       -EINVAL

"On header" is the state after EC 1A 00 28 1E, which leaves the pump on
its internal controller. The internal fan followed pwm2 in every column
(40%: 1545 to 1590 rpm).

Written back to back, 2 runs each, final state:

  pwm1 = 60%, pwm2 = 40% (patch 1)    source 1, pump 60%, fan 40%
  pwm1 = 40%, pwm1 = 60% (patch 1)    source 1, pump 60%
  pwm1_enable = 2, pwm1 = 60%         source 1, pump 60%
  pwm1_enable = 1, 2, 1               source 1
  pwm1 = 60%, pwm1_enable = 2         source 0

The failure in the linked issue needs the power-on state, which a USB
reset does not bring back, so it was measured from power-on (PSU
switched off), once per column, with the header at 100%. Source,
byte 9 of the status report (the duty the pump runs at) and pump rpm:

                           before         patch 1        patches 1-2
  no write yet             0  100  3570   0  100  3570   0  100  3570
  pwm2 = 40%               1  100  3570   0  100  3570   0  100  3570
  pwm1 = 40% (reported)    1  100  3570   1   40  1710   1   40  1710
  pwm1 = 60%               1   60  2430
  pwm1 = 40%               1   40  1725
  pwm1_enable = 2                                        0  100  3585

The two writes that patch 1 sends for a pwm1 write of the reported duty
reached the requested duty in all 19 trials, 9 with raw commands and 10
through the driver.

The commit in the Fixes: tag, cd258aca0dc4, first appeared in v7.3-rc1.

Zac Lanzon (2):
  hwmon: (asus_rog_ryujin) Fix pump control source on the Ryujin III
  hwmon: (asus_rog_ryujin) Add pwm1_enable for the Ryujin III pump

 Documentation/hwmon/asus_rog_ryujin.rst |  10 ++
 drivers/hwmon/asus_rog_ryujin.c         | 164 +++++++++++++++++++++++-
 2 files changed, 171 insertions(+), 3 deletions(-)


base-commit: 9edd5ab2656f040d726b5388f49ceac10bb2944f
-- 
2.53.0