Dears,
I have a generic requirement, I need to set some gpio pins let it default pull up, and user space could use the sys gpio command to change the status
, but I can't implement on SDK8.0, my follow as below.
1. I select gpio 1_14、gpio1_17、gpio3_19 of BBB and set the DTS file
gpio1_pins_default: gpio1_pins_default {
pinctrl-single,pins = <
0x38 ( PIN_OUTPUT_PULLUP | MUX_MODE7 ) /* (V13) gpmc_ad14.gpio1[14] */
0x44 ( PIN_OUTPUT_PULLUP | MUX_MODE7 ) /* (V14) gpmc_a1.gpio1[17] */
>;
};
gpio3_pins_default: gpio3_pins_default {
pinctrl-single,pins = <
0x1a4 ( PIN_OUTPUT_PULLUP | MUX_MODE7 ) /* (C13) mcasp0_fsr.gpio3[19] */
>;
};
&gpio1 {
pinctrl-names = "default";
pinctrl-0 = <&gpio1_pins_default>;
status = "okay";
};
&gpio3 {
pinctrl-names = "default";
pinctrl-0 = <&gpio3_pins_default>;
status = "okay";
};
2. when system into the kernel mode, those gpio status are pull up, but those still are the same pull up when I use the sys command to change the status to be pull down
echo 46 > /sys/class/gpio/export
echo 49 > /sys/class/gpio/export
echo 115 > /sys/class/gpio/export
echo out > /sys/class/gpio/gpio46/direction
echo out > /sys/class/gpio/gpio49/direction
echo out > /sys/class/gpio/gpio115/direction
echo 0 > /sys/class/gpio/gpio46/value
echo 0 > /sys/class/gpio/gpio49/value
echo 0 > /sys/class/gpio/gpio115/value
please give me a suggestion about the question, thanks.
B.R.
Joe
