Am 31.12.2017 um 12:17 schrieb Alexander Graf:
Am 30.12.2017 um 23:26 schrieb Frank Kunz <[email protected]>:
I try to control a few gpio pins via bash script. Board and OS version is:
cat /proc/device-tree/compatible
olimex,a13-olinuxinoallwinner,sun5i-a13
cat /etc/os-release
NAME="openSUSE Leap"
VERSION="42.3"
ID=opensuse
ID_LIKE="suse"
VERSION_ID="42.3"
PRETTY_NAME="openSUSE Leap 42.3"
ANSI_COLOR="0;32"
CPE_NAME="cpe:/o:opensuse:leap:42.3"
BUG_REPORT_URL="https://bugs.opensuse.org";
HOME_URL="https://www.opensuse.org/";
In /sys/class/gpio I do:
echo 3 > export
ls
export gpio3 gpiochip0 unexport
ls gpio3/
active_low device/ direction power/ subsystem/ uevent value
cat gpio3/direction
in
So when I want to change the pin direction:
echo out > gpio3/direction
bash: echo: write error: Unknown error 517
That is EPROBE_DEFER. The kernel signals that the requested device might be
probed later, ...or never. I guess that there might be some device tree item
missing, but from the kernel documentation I haven't found a solution for that.
Does anybody have an idea how to get that working?
Usually changing gpio direction is the responsibility of the pinmux driver. Can
you check if you have one loaded?
Thanks, that was the right hint. I analyzed it deeper and by using the
correct pin (35 instead of 3) it works. This sysfs entry has the pin
mapping:
/sys/kernel/debug/pinctrl/1c20800.pinctrl/pinmux-pins
Pinmux settings per pin
Format: pin (name): mux_owner gpio_owner hog?
pin 35 (PB3): (MUX UNCLAIMED) 1c20800.pinctrl:35
Br,
Frank
--
To unsubscribe, e-mail: [email protected]
To contact the owner, e-mail: [email protected]
