Re: [PATCH v3 2/2] hwmon: (fs1603) Add driver for TDK FS160x and FS1006 uPOL converters

[Guenter Roeck <linux@roeck-us.net>]

On Fri, Oct 30, 2026 at 08:35:38PM +0000, Kevin Jia wrote:
> The TDK FS1603, FS1604, FS1606 and FS1006 are uPOL DC-DC converters with
> an integrated inductor. They report input voltage, output voltage, output
> current and temperature, plus over-voltage, over-current and
> over-temperature status, over a proprietary I2C register map. They are
> not PMBus devices, and their register numbers collide with PMBus command
> codes: 0x21 is a status byte here where PMBus defines VOUT_COMMAND.
> 
> The parts have no ID register, and the FS1606-0600 and FS1606-2500
> presets change how telemetry is encoded: the -2500 uses the 20mV steps
> of the higher voltage parts, and the -0600 needs a current correction
> derived from the IOUT_GAIN register and the output voltage. The model is
> therefore taken from the device name or compatible.
> 
> The over-voltage and over-temperature protection thresholds are
> reported as in1_crit and temp1_crit. The over-voltage threshold is a
> percentage of the VOUT_SET target, so the driver reads VOUT_SET but
> never writes it: VOUT_SET is a two-byte pair, and a partial write leaves
> the part silently ignoring all register writes until its input power is
> cycled. The driver is read-only.
> 
> Power good is not exposed. It also deasserts while the output is
> disabled or soft-starting, so it would report a deliberately disabled
> output as a fault.
> 
> On boards that raise the rail with a feedback divider, VOUT_SET holds
> the feedback-pin target while the output voltage telemetry reports the
> rail. The driver measures the divider ratio at probe from the output
> voltage and the Fb register and scales the over-voltage threshold by
> it, so in1_crit is in the same domain as in1_input. A part whose Fb
> reads within four steps of the output keeps a ratio of one.
> 
> Co-developed-by: Abdurrahman Hussain <abdurrahman@nexthop.ai>
> Signed-off-by: Abdurrahman Hussain <abdurrahman@nexthop.ai>
> Signed-off-by: Kevin Jia <kjia@nexthop.ai>

Applied.

Thanks,
Guenter