linux/Documentation/hwmon/fsp-3y.rst
Václav Kubernát 1734b4135a hwmon: Add driver for fsp-3y PSUs and PDUs
This patch adds support for these devices:
- YH-5151E - the PDU
- YM-2151E - the PSU

The device datasheet says that the devices support PMBus 1.2, but in my
testing, a lot of the commands aren't supported and if they are, they
sometimes behave strangely or inconsistently. For example, writes to the
PAGE command requires using PEC, otherwise the write won't work and the
page won't switch, even though, the standard says that PEC is optional.
On the other hand, writes to SMBALERT don't require PEC. Because of
this, the driver is mostly reverse engineered with the help of a tool
called pmbus_peek written by David Brownell (and later adopted by my
colleague Jan Kundrát).

The device also has some sort of a timing issue when switching pages,
which is explained further in the code.

Because of this, the driver support is limited. It exposes only the
values that have been tested to work correctly.

Signed-off-by: Václav Kubernát <kubernat@cesnet.cz>
Link: https://lore.kernel.org/r/20210414080019.3530794-1-kubernat@cesnet.cz
[groeck: Fixed up "missing braces around initializer" from 0-day]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2021-04-20 06:50:14 -07:00

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.. SPDX-License-Identifier: GPL-2.0
Kernel driver fsp3y
======================
Supported devices:
* 3Y POWER YH-5151E
* 3Y POWER YM-2151E
Author: Václav Kubernát <kubernat@cesnet.cz>
Description
-----------
This driver implements limited support for two 3Y POWER devices.
Sysfs entries
-------------
* in1_input input voltage
* in2_input 12V output voltage
* in3_input 5V output voltage
* curr1_input input current
* curr2_input 12V output current
* curr3_input 5V output current
* fan1_input fan rpm
* temp1_input temperature 1
* temp2_input temperature 2
* temp3_input temperature 3
* power1_input input power
* power2_input output power