# GENERIC GPIO(8)

## NAME

generic_gpio - Driver for GPIO connected UPSes

## SYNOPSIS

generic_gpio -h

generic_gpio -a gpiochip0 [OPTIONS]

Note | This man page only documents the specific features of the generic_gpio driver. For information about the core driver, see nutupsdrv(8).

## SUPPORTED HARDWARE

This is the driver for GPIO attached UPS devices.

The driver has been tested against CyberPower CyberShield CSN27U12V attached to Orange Pi Zero GPIO.

More information about this UPS can be found here:

  https://www.cyberpowersystems.com/resources/csn27u12v-um/

## EXTRA ARGUMENTS

This driver supports the following optional settings in the ups.conf(5) file:

### Driver control:

rules=value

  A string consisting of sub-strings. Each sub-string describes GPIO line states conversion formula to specific NUT state, like

      nut_state=[^]line_num[logical_operation[^]line_num]...;

  The logical "Not" (`^`), "And" (`&`), and "Or" (`|`) operations are supported for now.

  The `nut_state` should correspond to NUT state, and `line_num` to the GPIO line number connected to UPS open collector pin.

  CyberShield CSN27U12V describes pins as:

  Battery state | State details | GPIO line
  ON BATTERY | Low when operating from utility line Open when operating from battery | 0
  REPLACE BATTERY | Low when battery is charged Open when battery fails the Self Test | 1
  BATTERY MISSING | Low when battery is present Open when battery is missing | 6
  LOW BATTERY | Low when battery is near full charge capacity Open when operating from a battery with < 20% capacity | 3

and then the rules value might be defined as

+

    rules = "OL=^0;OB=0;LB=3;RB=1;DISCHRG=0&^6;BYPASS=6;"

+ assuming battery pin connection to GPIO lines as listed in table.

+ Expecting simple formula to be used for each state, extra may increase state reliability and may need to be checked on each specific UPS.

### Battery Charge:

default.battery.charge.low=value

  An integer specifying the battery charge level reported in LB case.

## CONFIGURATION

Here is an example of GPIO driver configuration in ups.conf file:

    [CyberPower12v]
      driver = GENERIC_GPIO
      port = gpiochip0
      desc = "Modem and DNS server UPS"
      mfr = CyberPower
      model = "CyberShield CSN27U12V"
      rules = "OL=^0;OB=0;LB=3;RB=1;DISCHRG=0&^6;BYPASS=6;"
      default.battery.charge.low = 20

## SHUTDOWN COMMAND

This driver does not support shutdown command.

## INSTALLATION

This driver may be not built by default. You can build it by installing libgpiod and running `configure --with-gpio=yes`.

You also need to give proper permissions on the local serial device file (`/dev/gpiochip0` for example) to allow the run-time NUT driver user account to access it, like by adding the following rule to Linux `rules.d` directory:

    SUBSYSTEM=="gpio*", PROGRAM="/bin/sh -c '\
    chown -R nut:nut /dev/gpiochip0 && chmod -R 700 /dev/gpiochip0'

## AUTHOR

Modris Berzonis <modrisb@apollo.lv>

## SEE ALSO

### The core driver:

nutupsdrv(8), ups.conf(5)

### Internet resources:

- The NUT (Network UPS Tools) home page: https://www.networkupstools.org/historic/v2.8.5/

- libgpiod home page: https://git.kernel.org/pub/scm/libs/libgpiod/libgpiod.git/