fbtft TFT driver

[jgrulich]

I'm trying to bring working the 3.5' TFT Touchscreen. It's using the fbtft module with the following setup:

Code: (bash) [Select]

flexfb  width=320  height=480  regwidth=16 init=-1,0xb0,0x0,-1,0x11,-2,250,-1,0x3A,0x55,-1,0xC2,0x44,-1,0xC5,0x00,0x00,0x00,0x00,-1,0xE0,0x0F,0x1F,0x1C,0x0C,0x0F,0x08,0x48,0x98,0x37,0x0A,0x13,0x04,0x11,0x0D,0x00,-1,0xE1,0x0F,0x32,0x2E,0x0B,0x0D,0x05,0x47,0x75,0x37,0x06,0x10,0x03,0x24,0x20,0x00,-1,0xE2,0x0F,0x32,0x2E,0x0B,0x0D,0x05,0x47,0x75,0x37,0x06,0x10,0x03,0x24,0x20,0x00,-1,0x36,0x28,-1,0x11,-1,0x29,-3
fbtft_device debug=3 rotate=90 name=flexfb speed=16000000 gpios=reset:25,dc:24

I have the kernel modules for flexfb, it's in the staging directory. But it gives error message "Unknown parameter".

Has anybody experience with this driver, or any idea what to modify to bring this module working?

[jgrulich]

I've found that the LCD is supported by the generic tinylcd35 overlay. Unfortunately there are still some errors when loaded:

Code: (bash) [Select]

[    8.847700] fbtft: module is from the staging directory, the quality is unknown, you have been warned.
[    8.848245] fbtft: Unknown symbol fb_sys_write (err 0)
[    8.848278] fbtft: Unknown symbol sys_imageblit (err 0)
[    8.848316] fbtft: Unknown symbol sys_fillrect (err 0)
[    8.848588] fbtft: Unknown symbol sys_copyarea (err 0)
[    8.848701] fbtft: Unknown symbol fb_sys_read (err 0)
[    8.907968] ads7846: Unknown symbol hwmon_device_unregister (err 0)
[    8.908017] ads7846: Unknown symbol hwmon_device_register_with_groups (err 0)

Any idea what's wrong?

[bmarkus]

Jan

which piCore version and which kernel are you using?

[jgrulich]

piCore-7.0alpha2, kernel 4.1.6. Tested on Rasbian with the same kernel and it works.
I'd like to test on the latest TC version, but I don't have the kernel source files to make the modules.

[bmarkus]

Please update to the latest alpha release with 4.1.7 kernel. You can download all kernel modules from

http://tinycorelinux.net/7.x/armv6/releases/RPi/src/kernel/
http://tinycorelinux.net/7.x/armv7/releases/RPi2/src/kernel/

[jgrulich]

Hi Béla,

still the same error message:

Code: (bash) [Select]

modprobe: can't load module fbtft (kernel/drivers/staging/fbtft/fbtft.ko): unknown symbol in module, or unknown parameter

The same for the touchscreen controller:

Code: (bash) [Select]

modprobe: can't load module ads7846 (kernel/drivers/input/touchscreen/ads7846.ko): unknown symbol in module, or unknown parameter


[jgrulich]

This is the dmesg:

Code: (bash) [Select]

[    4.930700] fbtft: module is from the staging directory, the quality is unknown, you have been warned.
[    4.931069] fbtft: Unknown symbol fb_sys_write (err 0)
[    4.931091] fbtft: Unknown symbol sys_imageblit (err 0)
[    4.931112] fbtft: Unknown symbol sys_fillrect (err 0)
[    4.931223] fbtft: Unknown symbol sys_copyarea (err 0)
[    4.931300] fbtft: Unknown symbol fb_sys_read (err 0)

[   21.831099] ads7846: Unknown symbol hwmon_device_unregister (err 0)
[   21.831135] ads7846: Unknown symbol hwmon_device_register_with_groups (err 0)


[bmarkus]

Check module dependencies with modinfo, probably you must load additional modules.

[jgrulich]

Yes, you're right. It needs the video driver loaded first.
To switch to TFT I need con2fbmap. Please add to the repo.

[bmarkus]

Yes, you're right. It needs the video driver loaded first.
To switch to TFT I need con2fbmap. Please add to the repo.

Do not find con2fbmap source code.

[Rich]

Hi bmarkus
Is this of any use:
http://www.linuxquestions.org/questions/slackware-installation-40/how-to-get-displaylink-usb-to-show-text-console-4175527644/#post5290289

[jgrulich]

Good link. I'm using similar way now, two boot options of cmdline.txt. One with fbcon=map:10 and other without.
But this is not smart way to do so, if I need to switch it very often.
May be that there is some other way how to switch between fb0 and fb1 device output.

[Rich]

Hi jgrulich
Actually I posted the link because it listed where to find the source for con2fbmap.

[jgrulich]

Hi Rich,

I've tried several tricks in this link and several other, but still no lucky. I've tried to use this link:

Code: (bash) [Select]

https://github.com/notro/fbtft/wiki/Framebuffer-use

and tried to make the mirroring:

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sudo apt-get install cmake
git clone https://github.com/tasanakorn/rpi-fbcp
cd rpi-fbcp/
mkdir build
cd build/
cmake ..
make
sudo install fbcp /usr/local/bin/fbcp

Cmake works well, but make gives error that bcm_host.h can't be found and stops working.
I've tried to locate this file in the Rasbian source, but still no lucky.
Please help with compilation to bring the mirroring  working.

[Rich]

Hi jgrulich
I'm not running a Raspberry Pi myself, but this doesn't look right:

Code: [Select]

sudo apt-get install cmakePi has a complete tool set for building called  compile-essentials.tcz,  and  cmake.tcz  is in the repository. You might also
need one of the Linux headers extensions installed.