Hi Robert, thank you for the fast reply.
I hade :
P9_11 {
gpio-name = "P9_11";
gpio = <0x35 0x1e 0x0>;
output;
dir-changeable;
}
Following your directions I modify the initial code as follow:
P9_11 {
gpio-hog;
gpios = <11 GPIO_ACTIVE_HIGH>;
output-low;
gpio-name = "P9_11";
gpio = <0x35 0x1e 0x0>;
dir-changeable;
};
Is now correct?
Il giorno giovedì 27 febbraio 2020 16:16:07 UTC+1, RobertCNelson ha scritto:
>
> On Thu, Feb 27, 2020 at 9:14 AM Faby <[email protected] <javascript:>>
> wrote:
> >
> > Hi,
> > I would like to set low the logic level on the P9_11 during the power
> on, so before the linux kernel has bees loaded.
> > I do not have experince with tree device and boot loader so I am here to
> ask your help.
> >>>
> >>> For what I was able to discover and collecting fragmentated
> informations, I have to modify the file
> "/boot/dtbs/4.14.71-bone-rt-r17/am335x-boneblack-uboot.dtb".
> >
> > This file should be responsable for give the earlier informations during
> the power on start up of the system.
> > I have decompiled this file and added:
> >
> > pinmux_P9_11_gpio_pd_pin {
> > pinctrl-single,pins = <0x70 0x27>;
> > phandle = <0x180>;
> > };
> > P9_11_pinmux {
> > compatible = "bone-pinmux-helper";
> > status = "okay";
> > pinctrl-names = "default", "gpio", "gpio_pu", "gpio_pd", "gpio_input",
> "uart";
> > pinctrl-0 = <0x17d>;
> > pinctrl-1 = <0x17e>;
> > pinctrl-2 = <0x17f>;
> > pinctrl-3 = <0x180>;
> > pinctrl-4 = <0x181>;
> > pinctrl-5 = <0x182>;
> > };
> > P9_11 {
> > gpio-name = "P9_11";
> > gpio = <0x35 0x1e 0x0>;
> > output;
> > dir-changeable;
> > };
> >
> > So, I guess, the system in power up will be able to set up and drive
> this PIN.
> >
> > Due to the lack of specific knowledge in this area now I am stuck, I
> don't know how to precede.
>
> Use gpio-hog:
>
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm/boot/dts/am335x-bonegreen-wireless.dts?h=v5.6-rc3#n121
>
>
> Regards,
>
> --
> Robert Nelson
> https://rcn-ee.com/
>
--
For more options, visit http://beagleboard.org/discuss
---
You received this message because you are subscribed to the Google Groups
"BeagleBoard" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To view this discussion on the web visit
https://groups.google.com/d/msgid/beagleboard/3ee03dd1-c7cd-400c-94e5-074f3cd38f20%40googlegroups.com.
