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notro edited this page Jul 11, 2015 · 159 revisions

Linux Framebuffer drivers for small TFT LCD display modules.

<img src="http://www.adafruit.com/images/ID797.jpg" title="Video: Raspberry Pi boots with Adafruit 2.2" LCD display" border="10" />

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FBTFT development has moved
The FBTFT drivers are now in the Linux kernel: drivers/staging/fbtft (details).

Install

The FBTFT drivers are now included in the Raspberry Pi Foundation kernel and can be installed with plain rpi-update.
There is one piece missing and that is a DMA capable SPI controller driver to get max performance. So for fbcp and showing movies, the FBTFT kernel still has to be used.

See /boot/overlays/README and FBTFT RPI overlays for information about Device Tree overlays.

To use fbtft_device instead of a DT overlay, add to /boot/config.txt:

dtparam=spi=on

FBTFT kernel with SPI DMA

sudo REPO_URI=https://github.com/notro/rpi-firmware rpi-update

2015-07-11

2015-03-27

  • FBTFT support is now in raspberrypi/linux. This release only adds SPI DMA support on top of that.

  • pitft overlay changed name to pitft28-resistive

  • These modules are no longer present:

    • gpio_keys_device - DT overlay example
    • ads7846_device - Use ads7846 DT overlay instead. See /boot/overlays/README
    • gpio_mouse_device
    • stmpe_device
    • gpio_backlight_device
    • rpi_power_switch
    • spi-config

  • Builtin console fonts are not enabled (fbcon=font:XX).

  • Other kconfig options no longer enabled:

    • MOUSE_GPIO
    • GPIO_MCP23S08
    • DYNAMIC_DEBUG

  • 2015-02-07

    • Add Raspberry Pi 2 support

  • Changelog

Missing kernel modules?

Use rpi-source to get the matching kernel source, making it easy to build modules.
Run like this:
REPO_URI=https://github.com/notro/rpi-firmware rpi-source
Examples on how to build various modules

Step-by-step using FBTFT

Using the Adafruit 2.2" display as an example

Enable driver

Register device (the driver will load automatically)
sudo modprobe fbtft_device name=adafruit22

dmesg will show the default pin assignements, and that the driver is loaded.

   fbtft_device:  SPI devices registered:
   fbtft_device:      spidev spi0.0 500kHz 8 bits mode=0x00
   fbtft_device:      spidev spi0.1 500kHz 8 bits mode=0x00
   fbtft_device:  'fb' Platform devices registered:
   fbtft_device:      bcm2708_fb id=-1 pdata? no
   fbtft_device: Deleting spi0.0
   fbtft_device:  GPIOS used by 'adafruit22':
   fbtft_device:    'reset' = GPIO25
   fbtft_device:    'led' = GPIO23
   fbtft_device:  SPI devices registered:
   fbtft_device:      spidev spi0.1 500kHz 8 bits mode=0x00
   fbtft_device:      fb_hx8340bn spi0.0 32000kHz 8 bits mode=0x00
   graphics fb1: fb_hx8340bn frame buffer, 176x220, 75 KiB video memory, 16 KiB buffer memory, fps=20, spi0.0 at 32 MHz

Test

X Windows
FRAMEBUFFER=/dev/fb1 startx

Note: You might need to move an xorg config out of the way if X doesn't start:

sudo mv /usr/share/X11/xorg.conf.d/99-fbturbo.conf ~
Console
con2fbmap 1 1

Make it permanent (Debian)

Driver

Add to file /etc/modules

fbtft_device name=adafruit22 verbose=0
Auto login and startx

Auto login: modify file /etc/inittab


#1:2345:respawn:/sbin/getty --noclear 38400 tty1
1:2345:respawn:/bin/login -f pi tty1 </dev/tty1 >/dev/tty1 2>&1

Auto startx: modify file /etc/rc.local

su -l pi -c "env FRAMEBUFFER=/dev/fb1 startx &"

Ref: http://elinux.org/RPi_Debian_Auto_Login

Console at boot

Add kernel argument to file /boot/cmdline.txt

fbcon=map:10

For more: Boot console

Make it permanent (Arch Linux)

Add to file /etc/modules-load.d/raspberrypi.conf

spi_bcm2708
fbtft_device

Add to file /etc/modprobe.d/fbtft.conf

options fbtft_device name=adafruit22

If you find bugs or have problems, please submit an issue.

Thanks

Without the help from other people, this project would not exist

  • Matt Porter wrote st7735fb which FBTFT grew from
  • Texy has provided much input and testing that have helped move this project forward
  • Derek Campbell did the work to implement DMA
  • Several people have provided drivers and improvements
  • Donations have helped me buy displays and accessories

Also thanks to people that help answering questions about FBTFT.

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