From: dimitry@cos.flag.org
To: linux-kernel <linux-kernel@vger.kernel.org>
Cc: dimitry <dimitry@cos.flag.org>
Subject: gpiolib: GPIO_GET_LINEHANDLE_IOCTL and GPIO_GET_LINEEVENT_IOCTL at the same time
Date: Tue, 28 Aug 2018 09:33:11 -0400 (EDT) [thread overview]
Message-ID: <314029050.47161.1535463191699.JavaMail.zimbra@cos.flag.org> (raw)
It seems gpiolib only allows user to request either the line handle descriptor or the line event descriptor, but not both at the same time.
gpiohandle_request hr;
gpioevent_request er;
...
ioctl(fd, GPIO_GET_LINEHANDLE_IOCTL, &hr); // so far so good
ioctl(fd, GPIO_GET_LINEEVENT_IOCTL, &er); // resource busy
I have a situation where I am trying to have 1 thread monitor an open drain/source line for events, while another thread writes to it. Not entirely unlike i2c pulse stretching. Is this not possible with the current gpiolib design? Or am I doing something wrong? If not possible, is my only choice to run an endless loop checking for line state?
NB: I am not subscribed to the list. Please CC me directly in your replies.
Thank you,
Dimitry
reply other threads:[~2018-08-28 13:33 UTC|newest]
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