apt-get source linux-image-$(uname -r) in /usr/src in case you are going to run your kernel
sudo apt-get build-dep linux-image-$(uname -r)
sudo apt-get install kernel-package

The below stuff did not work, so don't try it. sudo apt-get install linux-image-rpi-rpfv linux-headers-rpi-rpfv

use rpi-update (do update it)
$ sudo rpi-update
It should give you the latest kernel and then reboot.

After that, Get rpi-source
$ sudo wget https://raw.githubusercontent.com/notro/rpi-source/master/rpi-source -O /usr/bin/rpi-source
$ sudo chmod +x /usr/bin/rpi-source
$ /usr/bin/rpi-source -q --tag-update
$ rpi-source

http://www.howtogeek.com/howto/ubuntu/how-to-customize-your-ubuntu-kernel/

make menuconfig - arrow keys were not working. the issue was with bash. to make it work, issue sh command and then make menuconfig should work.

sudo apt-get install libqt4-dev
#cd linux-xxx/
#cp /boot/config-uname -r .config
#make xconfig
# make-kpkg clean
$ fakeroot make-kpkg --initrd --append-to-version=-custom kernel_image kernel_headers

two .deb files are generated. one is linux image and other is linux headers.
install both .deb files. those are located in parent dir.
dpkg -i linux.deb and then reboot.
check uname -r after reboot.

Aug 27 01:19:03 ami-desktop kernel: [ 0.000000] Hello to ami's kernel log file to be checked for boot logs: /var/log/kern.log

1. locate 2.6.28.9-custom
2. delete the files manually and then sudo update-grub2

To uninstall custom kernel, make sure you are not using that kernel currently.

dpkg --list | grep kernel-image
sudo apt-get remove kernel-image-your-kernel-image
To see all the kernels list in grub bootloader screen, press SHIFT key.

insmod hello.ko --> insert the module
lsmode -> list all the loaded modules
rmmod hello -> remove the loaded module if present

modinfo hello.ko -> gives info abt that module

dmesg | tail -f -> to check the printk() output

1. how to login as root in ubuntu first change the password of root (if u r doing it for first time) sudo passwd root
   //change the password
   //to login into root, do
   su root

All compiled modules are in /lib/modules/uname -r/kernel/drivers/

best one: http://www.tldp.org/LDP/lkmpg/2.6/html/x569.html#AEN687

1. http://lwn.net/Kernel/LDD3/
2. https://github.com/martinezjavier/ldd3/
3. http://lwn.net/Articles/2.6-kernel-api/
4. http://opensourceforu.efytimes.com/2015/05/writing-a-basic-framebuffer-driver/
5. https://sysplay.in/ -> interesting way
6. http://www.tutorialsdaddy.com/2015/05/writing-character-device-driver/
7. https://appusajeev.wordpress.com/2011/06/18/writing-a-linux-character-device-driver/
8. http://derekmolloy.ie/writing-a-linux-kernel-module-part-1-introduction/
9. https://fabiobaltieri.com/2011/09/21/linux-led-subsystem/
10. https://0xax.gitbooks.io/linux-insides/content/ --> best one
11. http://linux-sunxi.org/SPIdev
12. nice doc on writing spi driver - http://invo-tronics.com/spi-driver-for-linux-based-embedded-system/

http://linux.die.net/lkmpg/x892.html https://fabiobaltieri.com/2012/05/20/linux-kernel-device-drivers-for-avr-v-usb-devices/

modinfo module.ko or objdump hello-1.ko --full-contents --section=.modinfo

sudo apt-get install mutt

mutt -H 001....path
OR

sudo apt-get install git-email

git format-patch HEAD^
git send-email --to <email address> --cc gregkh@linuxfoundation.org --cc linux-gpio@vger.kernel.org --cc linux-kernel@vger.kernel.org 001....patch

nice ascii flow diagram: http://asciiflow.com/ useful while sending RFCs
Reference: https://burzalodowa.wordpress.com/2013/10/05/how-to-send-patches-with-git-send-email/

make htmldocs

1. kernel module signature loading failed: Add
   CONFIG_MODULE_SIG=n
   in your module Makefile

1. http://www.slideshare.net/kerneltlv/linux-interrupts-63978201?qid=aba0244c-f180-42f6-a9ad-e5791dda14db&v=&b=&from_search=5

• https://events.linuxfoundation.org/sites/events/files/slides/petazzoni-device-tree-dummies.pdf
• install sudo apt install device-tree-compiler @ dtc

cd linux-stable

cp /boot/config-uname -r .config

yes '' | make oldconfig

make menuconfig
make clean

make -j getconf _NPROCESSORS_ONLN deb-pkg LOCALVERSION=-custom

You’ll find your new kernel packages one directory up. They’ll be easily identifiable by their version number

cd ..
sudo dpkg -i linux-firmware-image-4.11.1-custom_4.11.1-custom-1_amd64.deb
sudo dpkg -i linux-libc-dev_4.11.1-custom-1_amd64.deb
sudo dpkg -i linux-headers-4.11.1-custom_4.11.1-custom-1_amd64.deb
sudo dpkg -i linux-image-4.11.1-custom-dbg_4.11.1-custom-1_amd64.deb
sudo dpkg -i linux-image-4.11.1-custom_4.11.1-custom-1_amd64.deb

then reboot

cd linux-src
zcat /proc/config.gz > .config
yes '' | make oldconfig
make menuconfig
make clean
make -j getconf _NPROCESSORS_ONLN LOCALVERSION=-custom
make modules_install

make modules_install

Copy the kernel to /boot directory
cp -v arch/x86_64/boot/bzImage /boot/vmlinuz-linux414

Make initial RAM disk
cp /etc/mkinitcpio.d/linux.preset /etc/mkinitcpio.d/linux414.preset sudo vim /etc/mkinitcpio.d/linux414.preset

... ALL_kver="/boot/vmlinuz-linux48"
...
default_image="/boot/initramfs-linux48.img"
...
fallback_image="/boot/initramfs-linux48-fallback.img"

Finally, generate the initramfs images for the custom kernel in the same way as for an official kernel:
mkinitcpio -p linux414

Copy System.map

The System.map file is not required for booting Linux. It is a type of "phone directory" list of functions in a particular build of a kernel. The System.map contains a list of kernel symbols (i.e function names, variable names etc) and their corresponding addresses. This "symbol-name to address mapping" is used by:

cp System.map /boot/System.map-YourKernelName ln -sf /boot/System.map-YourKernelName /boot/System.map

After completing all steps above, you should have the following 3 files and 1 soft symlink in your /boot directory along with any other previously existing files:

Kernel: vmlinuz-YourKernelName
Initramfs: Initramfs-YourKernelName.img
System Map: System.map-YourKernelName
System Map kernel symlink

grub-mkconfig -o /boot/grub/grub.cfg

and then reboot

• pacman -S linux-headers
  choose 14) linux-raspberry-headers