Re: [PATCH] hwmon: Add driver for MSI Mystic Light controller voltage sensors

[Tomasz Bojanowski]

On 11/7/26 06:57, Guenter Roeck wrote:
> I have the ones mentioned above, so I could test there if you want to
> add support for it.

Thanks for the offer. I looked at how the vendor software handles
these boards. There, the controller has its own USB ID (1462:7c94,
1462:7d75, 1462:7d76), and report 0xF0 is never used, which matches
the empty response you saw. Instead, about once a second, it writes
a 64-byte output report

  FA A0 00 00 00 00 00 00 00 01 FC 00 ... 00

and reads input reports until byte 2 is 0x01. The values are
little-endian u16 in mV:

  MS-7D75, MS-7D76: VDD MISC (bytes 11-12), CPU 1P8 (13-14),
                    CHIP Core (15-16)
  MS-7C94:          CPU VDDP (11-12), PROM Core (13-14)

This is from static analysis only.

Note that output report 0x01 with byte 1 set to 0xA0 switches the
controller to its bootloader (0416:3f00). It differs from the sensor
request only in the report ID, so the driver would only ever send
this one fixed request.

As a first step, could you send me the USB and HID report descriptors
of the three controllers? After that, I can send a small test program
for hidraw. Support for these boards would be a separate patch on top
of this driver.

Thanks,
Tomasz