Hello,
this morning I tried to see if the pin9_11 on power-up remain to logic
level 0 but it continues to go up immediately after power up and it never
changes its state.
Il giorno venerdì 28 febbraio 2020 23:39:02 UTC+1, Fabrizio Borrello ha
scritto:
>
> 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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