Thanks for your answer Andrew but I need that the board setup correctly the
pin at boot time (to avoid any trouble in the time elapsed between the DTB
is load and the kernel is ready).
I'm actually facing a strange thing, 1st the number I used to set gpio3_21
was wrong : gpio = <107 0>; This call require the GPIO number on the bank
and not the PIN number. So using : gpio = <21 0>; I end up with that result
:
root@arm:~# cat /sys/kernel/debug/gpio
GPIOs 0-31, platform/44e07000.gpio, gpio:
gpio-6 (cd ) in hi IRQ
GPIOs 32-63, platform/4804c000.gpio, gpio:
gpio-53 (? ) out lo
gpio-54 (? ) out lo
gpio-55 (? ) out hi
gpio-56 (? ) out lo
GPIOs 64-95, platform/481ac000.gpio, gpio:
GPIOs 96-127, platform/481ae000.gpio, gpio:
gpio-117 (TOR input ) out lo
root@arm:~# cat /sys/kernel/debug/gpio
GPIOs 0-31, platform/44e07000.gpio, gpio:
gpio-6 (cd ) in hi IRQ
GPIOs 32-63, platform/4804c000.gpio, gpio:
gpio-53 (? ) out hi
gpio-54 (? ) out lo
gpio-55 (? ) out hi
gpio-56 (? ) out lo
GPIOs 64-95, platform/481ac000.gpio, gpio:
GPIOs 96-127, platform/481ae000.gpio, gpio:
gpio-117 (TOR input ) out lo
So this is nice because that's means my DTB is correctly loaded, but the
pinmux register didn't change :
root@arm:~# cat /sys/kernel/debug/pinctrl/44e10800.pinmux/pins|grep 9ac
pin 107 (44e109ac.0) 00000027 pinctrl-single
0x27 means the register is set to INPUT | MODE7 ... Why ???? The gpio setup
and his register differ ... Can this cause me any trouble ? Or should I
ignore it ? Is it a problem from my pinctrl,pin setup in the DTB ?
Le mercredi 19 août 2015 06:35:25 UTC+2, AndrewTaneGlen a écrit :
>
> I had trouble (viz. gave up) working with input pins with the device tree.
> I ended up doing all the init at run time (once I'd made sure nothing else
> was using the same pins in the device tree).
> Check that you have removed any reference to the HDMI in your
> 'am335x-bone-common-no-capemgr.dtsi' file. I had to remove a 'status =
> "okay"' from the standard ''am335x-bone-common.dtsi', not sure if this is
> the same in the 'no cape' variant.
>
> For BBB expansion header P9, pin 23 (GPIO 1_17), AKA pin 49, I do the
> following to intialise an input for use as a switch:
>
> echo "49" > /sys/class/gpio/export
> echo in > /sys/class/gpio/gpio49/direction
> echo 1 > /sys/class/gpio/gpio49/active_low
>
> To read in the state I then use:
> head -1 /sys/class/gpio/gpio49/value
>
> e.g., in a script, use:
>
> SWITCH=$(head -1 /sys/class/gpio/gpio49/value)
>
> if [ ${SWITCH} = "1" ]; then
> ...
> fi
>
> For outputs I use the 'standard' led interface, as already used in the BBB
> device tree for the heartbeat/mmc leds.
> e.g., with the pnmux as you have done, add something like the following to
> the 'leds' section in the common dtsi file:
>
> led@6 {
> label = "my_led";
> gpios <&gpio1 16 GPIO_ACTIVE_HIGH>;
> linux,default-trigger = "none";
> default-state = "off";
> };
>
> Then set the output state as follows:
>
> echo 1 > /sys/devices/leds.4/leds/my_led/value
>
> Hope that helps.
> Andrew.
>
> On Wednesday, 19 August 2015 01:16:30 UTC+12, Paco Dupont wrote:
>>
>> I've replace the last part I added (&ocp...) by Nelson's advice on this
>> post :
>> https://groups.google.com/d/msg/beagleboard/iW4i-xy9zJw/JFrr5M9_IwAJ
>> &gpio3 {
>> torout0 {
>> gpio-hog;
>> gpios = <107 0>;
>> output-low;
>> line-name = "TOR input";
>> };
>> };
>>
>> Just trying for 1 pin but still the same output no change ...
>>
>
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