#### Kernel UPDATE for SH1106 OLED display
# references:
# https://wiki.zerophone.org/index.php/Framebuffer_driver_for_SH1106
# https://github.com/notro/fbtft/wiki/Development
# https://www.reddit.com/r/raspberry_pi/comments/4cnc12/sending_console_to_spi_displays/

    ## NOTE Kernel versions are different for Stretch - note changes below

    # Needed for make menuconfig
    sudo apt-get update
    sudo apt-get dist-upgrade
    sudo apt-get -y install libncurses5-dev

    # this should already be done with norns install i think
    sudo apt-get install git bc raspberrypi-kernel-headers
    git clone --depth=1 https://github.com/raspberrypi/linux

    cd ~/linux

    # Driver file appears to already be there - but the set_gamma looks like it needs to be patched
    sed 's/u32 \*curves/unsigned long *curves/' drivers/staging/fbtft/fb_sh1106.c

    ## Preparing the kernel module compilation
    # check with linux kernel you have with (adjust version# path below if needed)
    uname -r

    cp /usr/src/linux-headers-4.14.34-v7+/Module.symvers .
    cp /usr/src/linux-headers-4.14.34-v7+/.config .

    make modules_prepare
    # this needs to generate some scripts for later

    make menuconfig
        Device Drivers  ---> Staging Drivers ---> Support for small TFT LCD display modules  --->
        <M>   SH1106 driver
    
    # Save, Exit and then 
    make prepare

    make -C ~/linux SUBDIRS=drivers/staging/fbtft modules

    ## move the drivers    
    sudo cp -v ~/linux/drivers/staging/fbtft/*.ko /lib/modules/$(uname -r)/kernel/drivers/staging/fbtft/

    sudo depmod -a

    # change the gpios below to what you have wired for your display
    sudo modprobe fbtft_device custom name=fb_sh1106 debug=1 speed=2000000 gpios=reset:25,dc:24
    # check dmesg
    dmesg
    # test with (will show login prompt)
    con2fbmap 1 1
 
        #Modprobe example commands:
        #sudo modprobe fbtft_device name=adafruit13m debug=1 speed=2000000 gpios=reset:25,dc:23
        #sudo modprobe fbtft_device custom name=fb_sh1106 gpios=reset:5,dc:6 speed=32000000

        sudo modprobe fbtft_device custom name=fb_sh1106 debug=1 speed=2000000 gpios=reset:25,dc:24
        sudo modprobe fbtft_device name=adafruit22 debug=1 speed=2000000 gpios=reset:25,dc:24
        
# get this command to load at startup        
sudo nano /etc/rc.local

#Add the modprobe command here

# By default this script does nothing.
sudo modprobe fbtft_device custom name=fb_sh1106 debug=1 speed=2000000 gpios=reset:25,dc:24


# EDIT NORNS SOURCE FOR SCREEN

# edit norns/matron/src/hardware/screen.c
sudo nano ~/norns/matron/src/hardware/screen.c

# change line 138:
# surfacefb = cairo_linuxfb_surface_create("/dev/fb0");
# to
# surfacefb = cairo_linuxfb_surface_create("/dev/fb1");
# save

# and then rebuild norns
./waf configure
./waf