NAME

gpio_set_ctl − set control lines on GPIO card

SYNOPSIS

int gpio_set_ctl (eid, value)
int eid, value;

DESCRIPTION

Gpio_set_ctl enables you to set the control register of a GPIO interface.  Eid is an entity identifier of an open GPIO device file obtained from an open(2), dup(2), fcntl(2), or creat(2) call.  Value is the value to be written into the control register of the GPIO interface associated with eid.

Value is mapped onto the control lines on the interface card, with the least significant bit mapped to CTL0.  Only the x least significant bits are used, where x is the number of control lines available on the hardware interface being used. 

DEPENDENCIES

Series 300
Eid is an integer file descriptor (fildes) that identifies an open device special file.  For the current GPIO card, x is 2. 

RETURNS

Gpio_set_ctl returns 0 if successful, and −1 if an error was encountered. 

ERRORS

Gpio_set_ctl fails under the following circumstances and sets errno (see errno(2)) to the value in square brackets:

eid does not refer to an open file [EBADF];

eid does not refer to a GPIO device file [ENOTTY]. 

Hewlett-Packard Company  —  May 11, 2021