hello,
I want to set the P9_21(gpio3) pin of Beaglebone Green to the output pin
using Device Tree at startup, and set it to low level.
So, I wrote the following pinctrl-test.dts and created
pinctrl-test-00A0.dtbo.
/dts-v1/;
/plugin/;
/ {
compatible = "ti,beaglebone", "ti,beaglebone-black",
"ti,beaglebone-green";
/* identification */
part-number = "pinctrl-test";
version = "00A0";
/*
* Free up the pins used by the cape from the pinmux helpers.
*/
fragment@0 {
target = <&ocp>;
__overlay__ {
P9_21_pinmux { status = "disabled"; }; /* uart2_txd
*/
P9_22_pinmux { status = "disabled"; }; /* uart2_rxd
*/
};
};
fragment@1 {
target = <&am33xx_pinmux>;
__overlay__ {
pinctrl_test: pinctrl_test_pins {
pinctrl-single,pins = <
0x154 0x07 /* P9_21 OUTPUT | MODE7
*/
0x150 0x3f /* P9_22 INPUT | MODE7 */
>;
};
};
};
fragment@2 {
target = <&ocp>;
__overlay__ {
test_helper: helper {
compatible = "bone-pinmux-helper";
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_test>;
status = "okay";
};
};
};
};
And the created pinctrl-test-00A0.dtbo is described in the /boot/uEnv.txt
file as follows.
(omission)
###Additional custom capes
uboot_overlay_addr4=/lib/firmware/pinctrl-test-00A0.dtbo
#uboot_overlay_addr5=/lib/firmware/<file5>.dtbo
#uboot_overlay_addr6=/lib/firmware/<file6>.dtbo
#uboot_overlay_addr7=/lib/firmware/<file7>.dtbo
(omission)
The mode of P9_21 pin is changed to 0x07 as follows, but the direction of
/sys/class/gpio/gpio3 is still input.
root@beaglebone:/sys/kernel/debug/pinctrl/44e10800.pinmux-pinctrl-single#
cat pins | grep 954
pin 85 (PIN85) 44e10954 00000007 pinctrl-single
root@beaglebone:/sys/kernel/debug/pinctrl/44e10800.pinmux-pinctrl-single#
root@beaglebone:/sys/class/gpio/gpio3# cat direction
in
root@beaglebone:/sys/class/gpio/gpio3#
Is the GPIO pin mode setting not reflected in the direction of
/sys/class/gpio/gpio3 ?
How can I set /sys/class/gpio/gpio3 as an output pin to low level by using
device tree at startup ?
The environment used is as follows.
root@beaglebone:~# /opt/scripts/tools/version.sh
git:/opt/scripts/:[b39ec679648a6be8f25f48bd1c9784c1fc5a0c46]
eeprom:[A335BNLTBBG1BBG219036584]
model:[TI_AM335x_BeagleBone_Green]
dogtag:[BeagleBoard.org Debian Buster IoT Image 2020-04-06]
bootloader:[microSD-(push-button)]:[/dev/mmcblk0]:[U-Boot
2019.04-00002-g07d5700e21]:[location: dd MBR]
bootloader:[eMMC-(default)]:[/dev/mmcblk1]:[U-Boot
2019.04-00002-g07d5700e21]:[location: dd MBR]
UBOOT: Booted Device-Tree:[am335x-boneblack-uboot-univ.dts]
UBOOT: Loaded Overlay:[AM335X-PRU-RPROC-4-19-TI-00A0]
UBOOT: Loaded Overlay:[BB-ADC-00A0]
UBOOT: Loaded Overlay:[BB-BONE-eMMC1-01-00A0]
UBOOT: Loaded Overlay:[M-BB-BBG-00A0]
kernel:[4.19.94-ti-r42]
nodejs:[v10.15.2]
/boot/uEnv.txt Settings:
uboot_overlay_options:[enable_uboot_overlays=1]
uboot_overlay_options:[uboot_overlay_addr4=/lib/firmware/pinctrl-test-00A0.dtbo]
uboot_overlay_options:[uboot_overlay_pru=/lib/firmware/AM335X-PRU-RPROC-4-19-TI-00A0.dtbo]
uboot_overlay_options:[enable_uboot_cape_universal=1]
pkg check: to individually upgrade run: [sudo apt install --only-upgrade
<pkg>]
pkg:[bb-cape-overlays]:[4.14.20200430.0-0~buster+20200430]
pkg:[bb-wl18xx-firmware]:[1.20200420.1-0~buster+20200424]
pkg:[kmod]:[26-1]
pkg:[librobotcontrol]:[1.0.4-git20190227.1-0rcnee0~buster+20190327]
pkg:[firmware-ti-connectivity]:[20190717-2rcnee1~buster+20200305]
groups:[debian : debian adm kmem dialout cdrom floppy audio dip video
plugdev users systemd-journal bluetooth netdev i2c gpio pwm eqep remoteproc
admin spi iio docker tisdk weston-launch xenomai cloud9ide]
cmdline:[console=ttyO0,115200n8 bone_capemgr.uboot_capemgr_enabled=1
root=/dev/mmcblk0p1 ro rootfstype=ext4 rootwait coherent_pool=1M
net.ifnames=0 lpj=1990656 rng_core.default_quality=100 quiet]
dmesg | grep remote
[ 61.814804] remoteproc remoteproc0: wkup_m3 is available
[ 61.923073] remoteproc remoteproc0: powering up wkup_m3
[ 61.923101] remoteproc remoteproc0: Booting fw image
am335x-pm-firmware.elf, size 217168
[ 61.923354] remoteproc remoteproc0: remote processor wkup_m3 is now up
[ 63.522883] remoteproc remoteproc1: 4a334000.pru is available
[ 63.525211] remoteproc remoteproc2: 4a338000.pru is available
dmesg | grep pru
[ 63.522883] remoteproc remoteproc1: 4a334000.pru is available
[ 63.523050] pru-rproc 4a334000.pru: PRU rproc node pru@4a334000 probed
successfully
[ 63.525211] remoteproc remoteproc2: 4a338000.pru is available
[ 63.525386] pru-rproc 4a338000.pru: PRU rproc node pru@4a338000 probed
successfully
dmesg | grep pinctrl-single
[ 0.949822] pinctrl-single 44e10800.pinmux: 142 pins, size 568
dmesg | grep gpio-of-helper
[ 0.963207] gpio-of-helper ocp:cape-universal: ready
lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
END
root@beaglebone:~#
Regards,
--
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