[BeagleBone Black] How to set gpio pin when booting

Embedded Linux Discussions
14

Robert,
I added my question to this topic instead of creating a new topic. I also want to configure gpio pins in the device tree (DT).
I studied the above BB-P9_27-LED-00A0.dts example. I understand what fragment0, 1 and 2 are doing but I won’t need those fragments because my DT does not include P9_27_pinmux helper.
If I understand correctly, fragment3 uses gpio-leds. I don’t have a ‘led’ node in my DT. The only lines that have meaning to me are

label = "P9_27";
gpios = <&gpio3 19 GPIO_ACTIVE_HIGH>;
default-state = "off";

I am using an OSD3358 on a custom board. I have a working DT but my input lines (gpio1_12, 13 14 and 15) are inverted and all my outputs (gpio1_23, 24, 25) are OFF. (Note I have removed the LED related code so that I can use 23 and 24 for my own purpose)

I have read the gpio dt-bindings.
I understand to configure an input line ACTIVE_LOW that I need to insert something like this…
enable-gpios = <&gpio1 12 GPIO_ACTIVE_LOW>
or
data-gpios = <&gpio1 12 GPIO_ACTIVE_LOW>

I understand to configure an output line’s default value that I need to insert something like this…
default_state = OFF

I also want to change gpio1_12 input line name from ‘GPMC_AD12’ to ‘SW_0_IN’.
I also want to change gpio1_23 output line name from ‘GPMC_A7’ to ‘LED_G_OUT’.

Here is snippet from my DT

/ {
	compatible = "ti,am33xx";
	interrupt-parent = <&intc>;
	#address-cells = <1>;
	#size-cells = <1>;
	chosen { };

[...]
	ocp: ocp {
		compatible = "simple-bus";
		#address-cells = <1>;
		#size-cells = <1>;
		ranges;
		ti,hwmods = "l3_main";
[...]
		gpio1: gpio@4804c000 {
			compatible = "ti,omap4-gpio";
			ti,hwmods = "gpio2";
			gpio-controller;
			#gpio-cells = <2>;
			interrupt-controller;
			#interrupt-cells = <2>;
			reg = <0x4804c000 0x1000>;
			interrupts = <98>;
			gpio-line-names =
				"GPMC_AD0",	// 0
				"GPMC_AD1",	// 1
				"GPMC_AD2",	// 2
				"GPMC_AD3",	// 3
				"GPMC_AD4",	// 4
				"GPMC_AD5",	// 5
				"GPMC_AD6",	// 6
				"GPMC_AD7",	// 7
				"UART0_CTSN",	// 8
				"UART0_RTSN",	// 9
				"UART0_RXD",	// 10
				"UART0_TXD",	// 11
				"GPMC_AD12",	// 12
				"GPMC_AD13",	// 13
				"GPMC_AD14",	// 14
				"GPMC_AD15",	// 15
				"GPMC_A0",	// 16
				"GPMC_A1",	// 17
				"GPMC_A2",	// 18
				"GPMC_A3",	// 19
				"GPMC_A4",	// 20
				"GPMC_A5",	// 21
				"GPMC_A6",	// 22
				"GPMC_A7",	// 23
				"GPMC_A8",	// 24
				"GPMC_A9",	// 25
				"GPMC_A10",	// 26
				"GPMC_A11",	// 27
				"GPMC_BE1N",	// 28
				"GPMC_CSN0",	// 29
				"GPMC_CSN1",	// 30
				"GPMC_CSN2";	// 31
		}; // end of gpio1: gpio@4804c000
[...]
	}; // end of ocp: ocp
[...]
}; // end of '/'

&am33xx_pinmux {
	pinctrl-names = "default"";
	pinctrl-0 = <&gpio1_pins_default>;
[...]
	gpio1_pins_default: pinmux_gpio1_pins {
		pinctrl-single,pins = <
			AM33XX_IOPAD(0x830, PIN_INPUT_PULLUP | MUX_MODE7)
			AM33XX_IOPAD(0x834, PIN_INPUT_PULLUP | MUX_MODE7)
			AM33XX_IOPAD(0x838, PIN_INPUT_PULLUP | MUX_MODE7)
			AM33XX_IOPAD(0x83c, PIN_INPUT_PULLUP | MUX_MODE7)
			AM33XX_IOPAD(0x844, PIN_INPUT_PULLUP | MUX_MODE7)
			AM33XX_IOPAD(0x848, PIN_INPUT_PULLUP | MUX_MODE7)
			AM33XX_IOPAD(0x84c, PIN_INPUT_PULLUP | MUX_MODE7)
			AM33XX_IOPAD(0x858, PIN_INPUT_PULLUP | MUX_MODE7)
			AM33XX_IOPAD(0x85c, PIN_OUTPUT_PULLUP | MUX_MODE7)
			AM33XX_IOPAD(0x860, PIN_OUTPUT_PULLUP | MUX_MODE7)
			AM33XX_IOPAD(0x864, PIN_OUTPUT_PULLUP | MUX_MODE7)
		>;
	};
[...]
}; // end of &am33xx_pinmux

Q. What is the difference between ‘enable-gpios’ and ‘data-gpios’?
Q. What is the correct syntax for the above changes?
Q. Where is the code inserted?

Thank you,