After testing new YH-5151E devices, we found out that not all YH-5151E
work the same. The newly tested devices actually report vout correctly
in linear16 (even though they're still YH-5151E). We suspect that it is
because these new devices have a different firmware version, but that is
unconfirmed. The version cannot be queried through PMBus.
The compliant versions of YH-5151E report VOUT_MODE normally, so we turn
on the linear11 workaround only if VOUT_MODE doesn't report anything.
Signed-off-by: Václav Kubernát <kubernat@cesnet.cz>
Link: https://lore.kernel.org/r/20210513201110.313523-1-kubernat@cesnet.cz
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
I didn't properly test the driver for YH-5151E, so it was completely
broken. Firstly, the log/real mapping was incorrect in one case.
Secondly, PMBus specifies that output voltages should be in the linear16
encoding. However, the YH-5151E is non-compliant and uses linear11.
YM-2151E isn't affected by this. Fix this by converting the values
inside the read functions. linear16 gets the exponent from the VOUT_MODE
command. The device doesn't support it, so I have to manually supply the
value for it.
Both supported devices have now been tested to report correct vout
values.
Fixes: 1734b4135a ("hwmon: Add driver for fsp-3y PSUs and PDUs")
Signed-off-by: Václav Kubernát <kubernat@cesnet.cz>
Link: https://lore.kernel.org/r/20210429075337.110502-1-kubernat@cesnet.cz
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Exported pmbus symbols are only supposed to be used from PMBus code.
Introduce PMBUS symbol namespace to prevent misuse from other code.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
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>
Václav Kubernát