Enable Power-off pin

[Prototyx]

Hi,

Is there anyway to enable a power off pin ?

My BPI M2 Zero is on a carrierboard and it would be nice to be able to configure a pin which go to low level when the BPI is shuted down. So the power supply can be switched off also.

Is there any way to activate this feature ?

Thanks

PLMR

[avafinger]

Is there anyway to enable a power off pin ?

AFAIK BPI M2 zero (and possibly all other H2+/H3 like OPI,NANOPI,etc...) never turn off the power. I think the AR100 embedded controller is responsible for this. I think the newer u-boot has some support for AR100, not really sure.

But if you want a pin to go low when the kernel is in power off, yes it is possible but you have to add this to the kernel. You can use this kernel here: https://github.com/avafinger/linux-5.6.y or a newer one, support for H2+ and/or H3 is almost complete.

[Prototyx]

Hi, thanks for your reply.

My carrier board will take care of switching off the power for the BPI M2 Zero, So it's not a problem if the M2 never turn off the power.

I am sorry I am not experienced with kernel modification for now I have the 5.3.4 kernel. Do I have to decompile the .dtb file, modify it and recompile it ? My goal is to have the pin 37 (PA17) which goes low when BPI is shutted down. How can I add this feature in the kernel ? Is there a guide somewhere ?

Last thing, Is it a must to use a 5.6.y kernel for this ? Or can I modify my 5.3.4 kernel ?

Thanks for your help

[avafinger]

I am sorry I am not experienced with kernel modification for now I have the 5.3.4 kernel. Do I have to decompile the .dtb file, modify it and recompile it ? My goal is to have the pin 37 (PA17) which goes low when BPI is shutted down. How can I add this feature in the kernel ? Is there a guide somewhere ?

Last thing, Is it a must to use a 5.6.y kernel for this ? Or can I modify my 5.3.4 kernel ?

PS: Any kernel version will do and no need to edit dt. No guide, only kernel docs or some kernel book. There are many ways to do it, I don't know which way would work best. Maybe the best place to turn the pin low would be in u-boot if the kernel returns control to u-boot after Power down. I don't know anyone who has done it.

In kernel you should look for:

/**
 *  kernel_power_off - power_off the system
 *
 *  Shutdown everything and perform a clean system power_off.
 */
void kernel_power_off(void)

You also may post this question on linux-sunxi@googlegroups.com (there are kernel developers there).

[Prototyx]

Hi,

Ok I think I got the thing. But Before to power off the system I need to shut down. And I just discoverd that power button doesn't shutdown the board with the kernel 5.3.4.

In the device tree there is this part linked to the push button PWR:

    r_gpio_keys {
        compatible = "gpio-keys";
        pinctrl-names = "default";
        pinctrl-0 = <0x3c>;

        k1 {
            label = "shutdown";
            linux,code = <0x74>;
            gpios = <0xe 0x0 0x3 0x1>;          
        };
    };

It is written compatible ="gpio-keys" This is corresponding to the driver gpio_keys.c But I think this driver has not been compiled in the kernel

Here is the output of : ls /lib/modules/5.3.4/kernel/input/keyboard -->sun4i-lradc-keys.ko

Does it mean that I need to recompile the kernel by integrating the gpio-keys driver ?

Thanks

[avafinger]

Does it mean that I need to recompile the kernel by integrating the gpio-keys driver ?

Nope. It's built in: CONFIG_KEYBOARD_GPIO=y

Search: dmesg|grep input

I just can't remember if the gpios is the correct one for the BPI-M2Z. You need to lookup up the schematic.

[Prototyx]

Hi,

I checked the schematic and it looks correct :

Power key is wired on PL3

and the device tree looks ok also :

    pinctrl@1f02c00 {
        compatible = "allwinner,sun8i-h3-r-pinctrl";
        reg = <0x1f02c00 0x400>;
        interrupts = <0x0 0x2d 0x4>;
        clocks = <0x2f 0x3 0xf 0x10>;
        clock-names = "apb", "hosc", "losc";
        gpio-controller;
        #gpio-cells = <0x3>;
        interrupt-controller;
        #interrupt-cells = <0x3>;
        phandle = <0xe>;

        ...

        key_pins@0 {
            pins = "PL3";
            function = "gpio_in";
            phandle = <0x3c>;
        };

        ...

    };

    ...

    r_gpio_keys {
        compatible = "gpio-keys";
        pinctrl-names = "default";
        pinctrl-0 = <0x3c>;

        k1 {
            label = "shutdown";
            linux,code = <0x74>;
            gpios = <0xe 0x0 0x3 0x1>;          
        };
    };

What Can I miss ?

Thanks,

PLMR

[avafinger]

dmesg|grep input

[Prototyx]

Hi,

Here is the output of dmesg | grep input

[ 6.713937] input: sunxi-ir as /devices/platform/soc/1f02000.ir/rc/rc0/input0

Any thoughts ?

PLMR

[Prototyx]

Hi again,

I checked in your source code of linux-5.6-y kernel.

In the file \arch\arm\configs\m2z_defconfig : Line 2226: # CONFIG_KEYBOARD_GPIO is not set

So I think that's why it doesn't work. It should be the same for 5.3.4.

I will try to compile a new kernel with this flag activated. What do you use for cross compilation ? Is it possible to compile it on BPI M2Z ?

[avafinger]

Interesting, it should have been set.

I will try to compile a new kernel with this flag activated. What do you use for cross compilation ?

arm-linux-gnueabihf

Is it possible to compile it on BPI M2Z ?

Yes. You can follow these instructions here: https://github.com/avafinger/nanopi-m4-ubuntu-base-minimal#mainline-kernel-510 Don't forget to install the necessary dependencies to build a kernel. zImage is the kernel and study the /boot partitions.

[Prototyx]

Hi,

Where can I find the source code of your kernel 5.3.4 ? Because when I download the source code of your release 5.3.4 it's not the source code of the kernel

And your repository of linux 5.3.y is empty.

Thanks for your help

[Prototyx]

Hi again,

I compiled a kernel from you repository 5.6.y, but unfortunately the board doesn't start after installing the kernel. I am using your image of ubuntu 16.04

Here is what I did for building :

make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- m2z_defconfig
make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- oldconfig
make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- INSTALL_MOD_PATH=output zImage 
make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- INSTALL_MOD_PATH=output dtbs
make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- INSTALL_MOD_PATH=output modules
make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- INSTALL_MOD_PATH=output modules_install
export KV=$(strings ./arch/arm/boot/Image |grep "Linux version"|awk '{print $3}')
make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- INSTALL_HDR_PATH=output/usr/src/linux-headers-${KV} headers_install

Then I copied via SSH the content of output directory in my home directory of BPI M2Z, the Zimage and the dtb file.

And then for installing

sudo cp -vfr ./output/* /
sync
sudo cp -fv ./zImage_v5.6.0 /boot
sync
sudo cp -fv ./bpi-m2-zero.dtb_v5.6.0 /boot
sync

And make it current kernel

cd /boot
sudo ln -sf zImage_v5.6.0 zImage
sudo ln -sf bpi-m2-zero.dtb_v5.6.0 bpi-m2-zero.dtb
cd ~
sync

And unfortunately if I do sudo reboot then the board doesn't start anymore

Did I make something wrong ?

Sorry for all these questions ...

[avafinger]

Please, restore the previous links in order to boot the older kernel. And what is the output of: export KV=$(strings ./arch/arm/boot/Image |grep "Linux version"|awk '{print $3}') echo $KV

[avafinger]

it should be something like:

sudo cp -fv ./arch/arm/boot/zImage /boot/zImage${KV} sudo cp -vf ./arch/arm/boot/dts/bpi-m2-zero-v4.dtb /boot/bpi-m2-zero-v4.dtb${KV} sudo cp -vfr ./output/usr/ /usr/ sudo cp -vfr ./output/lib/ /usr/lib/ sync cd /boot
sudo ln -sf zImage${KV} zImage sudo ln -sf bpi-m2-zero-v4.dtb${KV} bpi-m2-zero.dtb

check if you have: /lib/modules/ or /usr/lib/modules/

[Prototyx]

Hi;

echo $KV
5.6.0-rc7+

Thanks for your support, it's a first time for me with a kernel building ...

[Prototyx]

Hi,

So now the board is able to boot with the new kernel but I lost at least HDMI and Wifi. But I can see the heartbeat and now the stop button is working.

What could cause the HDMI and Wifi issue ?

[avafinger]

ls /usr/lib ls /lib

[Prototyx]

ls /usr/lib/modules 5.6.0-rc7+

ls /lib/modules 4.17.4-m2z 4.18.4-m2z 4.4.0-204-generic 5.3.4

I don't know why but in /lib/modules it seems that 5.6.0-rc7+ is missing

[avafinger]

fix with: *sudo cp -vfr ./output/lib/ //lib/**

[Prototyx]

Hi,

Wifi is back but not HDMI. I don't know if it's because I mess up with the kernel installation. I will try again by doing right the first time.

Thanks for your help.

[Prototyx]

Hi,

Ok so now everything is working with the new kernel by doing the installation right. I added also the flag in the config file CONFIG_POWER_RESET=y By enabling this, there is the gpio-poweroff driver.

I modified my device tree by adding :

/dts-v1/;

/ {

 ...

pinctrl@1c20800 {
            reg = <0x1c20800 0x400>;
            interrupts = <0x0 0xb 0x4 0x0 0x11 0x4>;
            clocks = <0x3 0x36 0x10 0x11 0x0>;
            clock-names = "apb", "hosc", "losc";
            gpio-controller;
            #gpio-cells = <0x3>;
            interrupt-controller;
            #interrupt-cells = <0x3>;
            compatible = "allwinner,sun8i-h3-pinctrl";
            phandle = <0xc>;
...

                       poweroff_pins@0 {             /* This line has been added */
                           pins = "PA17";            /* This line has been added */
                           function = "gpio_out";   /* This line has been added */
               };                                             /* This line has been added */
          };

...

gpio_power_off {                            /* This line has been added */
        compatible = "gpio-poweroff";          /* This line has been added */
        gpios = <0xc 0x0 0x11 0x1>;             /* This line has been added */
    };                                                      /* This line has been added */
};

then

sudo dtc -I dts -O dtb -o bpi-m2-zero-v4.dtb_5.6.0-rc7+ m2z.dts
sync && sudo reboot

But nothing happens on this pin PA17 when I shut down the system Anybody has experience with gpio-poweroff driver ?

Thanks

[Prototyx]

Hi,

Finally it works, it was a mistake in the .config file. I missed something in menuconfig for building kernel. Just check in the .config file that both following flags are set :

CONFIG_POWER_RESET=y
CONFIG_POWER_RESET_GPIO=y

Thank you very much avafinger for you support !