Hello,
I add into the file am335x-boneblack-uboot.dts located at
/opt/source/dtb-4.14-ti/src/arm, right at the very end as follow:
I
&gpio0 {
adc_reset_pin {
gpio-hog;
gpios = <30 GPIO_ACTIVE_HIGH>;
output-low;
line-name = "ADC_RESET_PIN_POWER_ON";
};
};
then I followed the commands sequence:
make
sudo make install
sudo reboot
After reboot I checked if the file am335x-boneblack-uboot.dtb located at
/boot/dtbs/4.14.71-bone-rt-17 hat the gpio-hog inside.
And Yes it is there under the controller:
gpio@44e07000 {
compatible = "ti,omap4-gpio";
ti,hwmods = "gpio1";
gpio-controller;
#gpio-cells = <0x2>;
interrupt-controller;
#interrupt-cells = <0x2>;
reg = <0x44e07000 0x1000>;
interrupts = <0x60>;
gpio-line-names = "MDIO_DATA", "MDIO_CLK", "SPI0_SCLK", "SPI0_D0",
"SPI0_D1", "SPI0_CS0", "SPI0_CS1", "ECAP0_IN_PWM0_OUT", "LCD_DATA12",
"LCD_DATA13", "LCD_DATA14", "LCD_DATA15", "UART1_CTSN", "UART1_RTSN",
"UART1_RXD", "UART1_TXD", "GMII1_TXD3", "GMII1_TXD2", "USB0_DRVVBUS",
"XDMA_EVENT_INTR0", "XDMA_EVENT_INTR1", "GMII1_TXD1", "GPMC_AD8",
"GPMC_AD9", "NC", "NC", "GPMC_AD10", "GPMC_AD11", "GMII1_TXD0",
"RMII1_REFCLK", "GPMC_WAIT0", "GPMC_WPN";
linux,phandle = <0x35>;
phandle = <0x35>;
adc_reset_pin {
gpio-hog;
gpios = <0x1e 0x0>;
output-low;
line-name = "ADC_RESET_PIN_POWER_ON";
};
};
On Monday I will test the it.
Thank you so much for your help and for supporting my request till here.
Have a nice WE.
Il giorno giovedì 27 febbraio 2020 16:14:17 UTC+1, Faby ha scritto:
>
> 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.
>
> Please help.
>
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