[How about kpatch for kernel hot upgrade without reboot]

From linux kernel 4.x, using patch to upgrade without reboot.

This is source: https://github.com/dynup/kpatch

Who had use it in arm, or have a tutorial?

[Using pwm without rebuilding kernel]

You can modify /boo/dtb/*Banana*.dtb

use tool dtc extract *dtb to dos : sudo dtc -I dtb -O dts your_board.dtb -o your_borad.dts

open dos, and find 'pwm@'

 

like this 

                pwm@01c20e00 {
                        compatible = "allwinner,sun7i-a20-pwm";
                        reg = <0x1c20e00 0xc>;
                        clocks = <0xb>;
                        #pwm-cells = <0x3>;
                        status = "okay";
                        pinctrl-names = "default";
                        pinctrl-0 = <0x35 0x36>;
                };

 

 

 

[Armbian 4.83 SPI driver]

I'm glad that it finally worked.

 

udev, I guess? (based on comments in spidev.c and kernel spidev documentation)

dev = device_create(spidev_class, &spi->dev, spidev->devt,
   spidev, "spidev%d.%d",   spi->master->bus_num, spi->chip_select);

bus_num: 32766

chip_select: 0