Re: [PATCH v3 3/3] hwmon: (pmbus/tda38640) Add workaround for bug in SVID mode

From: Guenter Roeck
Date: Sat Aug 12 2023 - 08:33:16 EST


On 8/2/23 12:31, Naresh Solanki wrote:
From: Patrick Rudolph <patrick.rudolph@xxxxxxxxxxxxx>

TDA38640 can operate in either PMBus mode or SVID mode.
In SVID mode, by design ENABLE pin is the only option for controlling
the output rail.

In scenarios that utilizes the chip in SVID mode with ENABLE pin either
grounded or tied to logic high & software control is desired then use
dt property 'infineon,en-svid-control' to enable the below workaround.

The workaround utilizes ENABLE pin polarity flipping to control
output rail.

If property 'infineon,en-svid-control' is specified then
determine if chip is in SVID mode by checking BIT15 of MTP memory offset
0x44 as described in the datasheet.

If chip is in SVID mode then apply the workaround by
1. Determine EN pin level
2. Maps BIT7 of OPERATION(01h) to EN_PIN_POLARITY(BIT1) of
PB_ON_OFF_CONFIG.

Signed-off-by: Patrick Rudolph <patrick.rudolph@xxxxxxxxxxxxx>
Signed-off-by: Naresh Solanki <Naresh.Solanki@xxxxxxxxxxxxx>

For my reference:

Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>

We still have to wait for dt patch approval.

Guenter