Re: [PATCH v2 1/2] hwmon:(pmbus/tda38740a) TDA38740A Voltage Regulator Driver
From: Guenter Roeck
Date: Sun Feb 01 2026 - 19:29:47 EST
On 1/22/26 03:42, ashish yadav wrote:
Hi Guenter,
Please find my response inline.
Thanks & Regards
Ashish Yadav
On Tue, Jan 13, 2026 at 8:40 PM Guenter Roeck <linux@xxxxxxxxxxxx> wrote:
The chip telemetry would still show Vout as 0.7V as it does not know
On 1/12/26 23:24, ashish yadav wrote:
The need for this, especially why it would only be needed for PMBUS_READ_VOUT
but not for any other VOUT related commands, is still insufficiently explained
(and I failed to understand the rationale provided earlier).
It is specifically needed for READ_VOUT as it is being used by
external controller to monitor the rail health.
Other Vout related parameters are used internally in the IC to for
output voltage related protections and does not impact any external
decision making.
Sorry, that doesn't really make sense. How would the chip know to match
VOUT with its VOUT limits if both don't use the same scale ?
about the external feedback resistors.
Hence, no need to scale internal Vout related parameters.
This scale is only for external vendor use to tweak their telemetry
output voltage reading.
You fail to explain why VOUT_SCALE_LOOP - which is supposed to handle such
situations - can not be used, and why it would be acceptable for other VOUT
related attributes such as VOUT_MIN, VOUT_MAX, VOUT_MARGIN_LOW, VOUT_MARGIN_HIGH,
and the various VOUT fault limits to show the wrong values.
For reference:
VOUT_SCALE_LOOP:
"Used to account for any external attenuation network on VOUT sense
feedback and provide correct VOUT reporting."
Guenter