[v3,0/3] hwmon: (pmbus/ltc2978) Set voltage resolution

Message

Mårten Lindahl June 14, 2022, 9:51 a.m. UTC

Hi!

When checking if a regulator supports a voltage range, the regulator
needs to have support for listing the range or else -EINVAL will be
returned.

This support does not exist for the LTC2977 regulator, so this change
adds support for list voltage to the pmbus regulators by adding
regulator_list_voltage_linear to the pmbus_regulator_ops. It also
defines the voltage resolution for regulators LTC2972/LTC2974/LTC2975/
LTC2977/LTC2978/LTC2979/LTC2980/LTM2987 based on that they all have the
same stepwise 122.07uV resolution, and scales the resolution to a 1mV
resolution which is easier to handle.

These patches have been tested on an ARTPEC-8 developer board with a group
of LTC2977 power regulators.

Kind regards
Mårten Lindahl

Changes in v3:
 - Move read of low/high margins into local functions
 - Add check for invalid selector value
 - Introduce new macro PMBUS_REGULATOR_STEP(_name, _id, _voltages, _step)

Changes in v2:
 - Correct #define format
 - Change dev_err to dev_warn
 - Add new pmbus_regulator_list_voltage function
 - Cache low/high vout margins

Mårten Lindahl (3):
  hwmon: (pmbus) Introduce and use cached vout margins
  hwmon: (pmbus) Add list_voltage to pmbus ops
  hwmon: (pmbus/ltc2978) Set voltage resolution

 drivers/hwmon/pmbus/ltc2978.c    |  44 +++++++++++--
 drivers/hwmon/pmbus/pmbus.h      |   8 ++-
 drivers/hwmon/pmbus/pmbus_core.c | 108 ++++++++++++++++++++++++++-----
 3 files changed, 137 insertions(+), 23 deletions(-)